Promoting effect of super absorbent polymer on hydrate formation

小学上册英语第三单元期中试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.I enjoy exploring the wonders of ________ (宇宙) and learning about space.2.The ________ (花卉) market has many types of flowers.3.Which element is essential for breathing?A. HeliumB. OxygenC. HydrogenD. CarbonB4.Which of these is a sea creature?A. EagleB. SharkC. TigerD. ElephantB5. A _______ is a piece of land surrounded by water on three sides.6.The __________ Ocean is located between Africa and Australia.7. A __________ is a beautiful coastal region.8.Planting flowers can enhance your garden's aesthetic ______. (种植花卉可以提升你花园的美观性。

)9.How many words are in a sentence?A. 1B. 5C. 10D. VariesD10.Which planet is known as the Blue Planet?A. MarsB. EarthC. VenusD. JupiterB11.What do we call a person who studies the effects of globalization?A. Global SociologistB. AnthropologistC. Political ScientistD. HistorianA12.I write with a _____ (pen/pencil).13.The squirrel's sharp claws help it climb ______ (树木).14.We can _______ a kite in the wind.15.The _______ (The Enlightenment) paved the way for modern democracies.16.My name is . (我叫)17.The chemical formula for chloric acid is ______.18. A covalent bond involves the sharing of ______.19.What do we call the device we use to call people?A. TelephoneB. RadioC. TelevisionD. ComputerA20.My dog's fur is ______ (黑色) and shiny.21.I like to keep a journal where I write my ______ (梦想) and aspirations. It motivates me to work hard.22.We should _______ our dreams and goals.23.Abraham Lincoln was the _____ (president) during the Civil War.24. A zebra has black and ______ stripes.25. A _____ (74) is a large flat area of grassland.26.__________ (环境保护) often involves understanding chemical interactions in nature.27.What is the freezing point of water?A. 0°CB. 50°CC. 100°CD. 25°CA28.My sister, ______ (我妹妹), loves to play with dolls.29.My friend is a _____ (医生) in a hospital.30.Pine trees stay _______ all year round.31.The __________ was a significant period of cultural change in the 1960s. (反文化运动)32.We are going to the ___. (park)33.My sister loves to care for her ______ (小猫).34.Rainforests are known for their rich ______.35.The _____ (zookeeper) cares for the animals.36.The ________ (湖) is full of fish.37.What do you call an animal that eats both plants and meat?A. HerbivoreB. CarnivoreC. OmnivoreD. InsectivoreC38.What do we call the study of plants?A. ZoologyB. BotanyC. EcologyD. BiologyB39.What is the name of the famous superhero who wears a cape?A. BatmanB. SupermanC. Iron ManD. Captain AmericaB40.How many stars are estimated to be in the Milky Way galaxy?A. 100 millionB. 200 billionC. 400 billionD. 1 trillion41. A comet's tail always points away from the ______.42.小貂) is playful and curious. The ___43.What is the capital of Switzerland?A. ZurichB. GenevaC. BernD. BaselC44. A parakeet can learn to ______ (说话).45.I enjoy ______ with my family. (traveling)46. A __________ is an area of land dedicated to wildlife.47.What is the name of the famous clock tower in London?A. Big BenB. Eiffel TowerC. Statue of LibertyD. Colosseum48.What do you call a large body of saltwater?A. RiverB. LakeC. OceanD. PondC49.The ________ (植物导向) can shape landscapes.50. A rabbit has long _____ ears.51.My sister is a ______. She enjoys doing crafts.52.Genghis Khan founded the ________ Empire.53.What is the main purpose of a teacher?A. To entertainB. To educateC. To superviseD. To judgeB To educate54.We will go to the _____ (zoo/museum) on Saturday.55.My ________ (玩具名称) is soft and cuddly.56.What do we call the process of breathing in?A. InhaleB. ExhaleC. BreatheD. Respire57.The chipmunk stores nuts in its ______.58.I like to play ______ (video games) on weekends.59.What do we call a young chicken?A. DucklingB. CalfC. ChickD. Foal60.She has a _____ (funny) joke.61.My favorite color is ________ (绿色) because it's fresh.62.The North Star is also called ______.63.What do bees make?A. MilkB. HoneyC. SugarD. JamB64.Martin Luther King Jr. fought for _____ rights.65.What do we call a person who studies the effect of diet on health?A. NutritionistB. DietitianC. BiologistD. PhysicianA66.What do we call the food we eat in the morning?A. DinnerB. LunchC. BreakfastD. Snack67.I have a toy _______ that can change shapes and forms for fun.68.My cousin is an excellent __________ (演说家).69.I love to watch _____ (小动物) explore their surroundings.70.My favorite dish is ______ (饺子).71.What is the name of the famous rock formation in Australia?A. Ayers Rock (Uluru)B. Great Barrier ReefC. Sydney Opera HouseD. The Twelve ApostlesA72.My sister has a collection of ____ (postcards).73.What is the name of the famous cat in the children's book series by Dr. Seuss?A. GarfieldB. Puss in BootsC. The Cat in the HatD. Tom CatC74.The _____ (绿意盎然) scenery is refreshing.75.What do we call the distance around a circle?A. DiameterB. RadiusC. CircumferenceD. AreaC76.Which animal is known for its ability to change color?A. ChameleonB. ElephantC. DogD. CatA77.The turtle is very ___ (slow).78.The kangaroo hops and carries its baby in its _________. (育儿袋)79.The children are ________ in the playground.80.My brother is a ______. He enjoys participating in sports.81.The ______ is the outer layer of a tree.82. A _______ is a special type of mixture with tiny particles that never settle.83.What do you call someone who studies the stars?A. GeologistB. BiologistC. AstronomerD. MeteorologistC84.What do you call a person who plays chess?A. Chess playerB. GambitC. StrategistD. PlayerA85.My sister has a lovely _______ (我妹妹有一个可爱的_______).86.Nebulas are giant clouds of ______.87.Which color is a banana?A. RedB. YellowC. BlueD. GreenB88.The __________ (世界大战) changed the course of history.89.I like to _______ (分享) my ideas.90.The _______ (青蛙) is green.91.I found a ________ in the leaves.92.She is ___ (running/jumping) in the field.93. A __________ (化学网络) connects researchers and promotes innovation.94.My birthday is in ___. (July, cold, happy)95.The Voyager spacecraft have traveled beyond the _______ of our solar system.96.I have a toy ______ (汽车). It goes very ______ (快).97.What do you call the animal that is known for its stripes?A. LeopardB. TigerC. ZebraD. Cheetah98.The chemical formula for sodium acetate is _______.99.Asteroids are smaller than _______ but larger than meteoroids.100.Which animal is often kept as a pet and barks?A. CatB. BirdC. DogD. FishC。

Atherosclerosis152(2000)433–440Probucol promotes reverse cholesterol transport in heterozygous familial hypercholesterolemia.Effects on apolipoproteinAI-containing lipoprotein particlesAhmed Adlouni a,*,Mariame El Messal b,Rachid Saı¨le a,Henri-Joseph Parra c,Jean-Charles Fruchart d,Noredine Ghalim ea Laboratoire de Recherche sur les Lipoprote´ines,Faculte´des Sciences Ben Msik,Sidi Othman,7955,Casablanca,Moroccob Laboratoire de Biochimie et Biologie Cellulaire et Mole´culaire,Faculte´des Sciences Aı¨n Chock,Casablanca,Moroccoc Ser6ice d’Expertises Pharmacologiques,Institut Pasteur de Lille,Lille,Franced U325,INSERM,Institut Pasteur de Lille,Francee Laboratoire de Biochimie,Institut Pasteur du Maroc,Casablanca,MoroccoReceived5July1999;received in revised form8November1999;accepted9December1999AbstractIn order to investigate the effect of Probucol therapy on reverse cholesterol transport,apo AI-containing lipoprotein particles were isolated and characterized,and their cholesterol effluxing capacity and LCAT activity were assayed in four familial hypercholesterolemia patients before and after12weeks of Probucol therapy.Four major subpopulations of apo A-containing lipoprotein particles are separated before and after drug treatment;LpAI,LpAI:AII,LpAIV,LpAI:AIV:AII.Probucol reduces both total plasma and LDL-cholesterol(−17and−14%,respectively).Apo B decreases slightly(−7.6%).Plasma HDL-choles-terol and apo AI decrease by36.6and34.7%.LpA-I showed a marked decrease(−46%).Moreover,plasma LCAT and CETP activities were markedly increased under Probucol treatment.Analysis of lipoprotein particles showed that Probucol induces a decrease of protein content and an increase of cholesterol and triglycerides contents.Interestingly,Probucol induces an enhancement of LCAT activity in LpAI(4.5-fold).This drug induces a trend toward greater cholesterol efflux from cholesterol-preloaded adipose cells promoted by Lp AI and Lp AIV but not by Lp AI:AII.This study confirms the hypothesis,in addition to the lowering LDL-cholesterol levels and antioxidant effects of Probucol,that HDL reduction was not an atherogenic change in HDL system but may cause an antiatherogenic action by accelerating cholesterol transport through HDL system,promoting reverse cholesterol transport from peripheral tissues.©2000Elsevier Science Ireland Ltd.All rights reserved.Keywords:Probucol;Familial hypercholesterolemia;Lipoprotein particle composition;CETP activity;LCAT activity;Cholesterol efflux/locate/atherosclerosis1.IntroductionMany epidemiological studies have indicated that the plasma level of high-density lipoprotein(HDL)is in-versely correlated with the risk for coronary artery disease[1,2].It has been established that HDL exerts its protective effect by the‘reverse’transport of excess cholesterol from peripheral tissues to the liver[3,4]. Probucol,4,4%-(isopropylidene-dithio)-bis-(2,6-di-tert-butylphenol)was introduced in the early1970s as a cholesterol-lowering drug[5],and has been the focus of many clinical investigations because it is an antioxidant that also reduces plasma cholesterol concentration in patients with hypercholesterolemia and reduces tendon xanthoma in man[6,7].This raises a problem in at-tempting tofind out the effects of Probucol as an antioxidant from its effects as cholesterol-lowering agent.Probucol is a unique antiatherogenic drug,pro-ducing its effect by antioxidant action rather than hypolipidaemic effect.However,the exact mechanism of its antiatherogenic effect is unclear.This drug is known to reduce not only the total plasma cholesterol and low-density lipoprotein(LDL)-cholesterol but also HDL cholesterol[7].The reduction of HDL cholesterol*Corresponding author.Tel.:+212-2-704671;fax:+212-2-704675.E-mail address:aadlouni@(A.Adlouni).0021-9150/00/$-see front matter©2000Elsevier Science Ireland Ltd.All rights reserved. PII:S0021-9150(99)00493-1A.Adlouni et al./Atherosclerosis152(2000)433–440 434by Probucol is contradictory to the clinical results, which demonstrated that HDL has a protective role in coronary disease.Moreover,a close correlation be-tween the extent of xanthoma regression and HDL reduction under Probucol treatment has been reported [8].Protein particles isolated on the basis of apolipo-protein composition may have particular physiopatho-logical properties[3,9,10].HDL comprises two main subclasses:those containing,as the main protein com-ponents,apo A-I and apo A-II,designated Lp AI:AII; and those containing apo A-I but not apo A-II,desig-nated Lp AI.It has been well established that lower HDL concentration in coronary artery disease is linked with lower Lp AI levels,while Lp AI:AII levels are unaffected[11].This observation led to the hypothesis that Lp AI may represent the antiatherogenic lipo-protein particle.This is confirmed by‘in vitro’studies showing that cholesterol efflux from cells is mediated by Lp AI but not by LpAI:AII[3,12].Apo A-IV-contain-ing particles isolated from plasma comprise two main subpopulations:those containing,as the main protein components,apo A-IV and apo A-I,designated Lp AI:AIV:AII and those that contain apo A-IV but not apo A-I,designated Lp AIV.Both subpopulations of lipoprotein containing apo A-IV express LCAT and CETP activities and promote cholesterol efflux from adipose cells[13].To assess the effect of Probucol drug on reverse cholesterol transport,we characterized the major sub-classes of HDL lipoproteins isolated on the basis of apolipoprotein composition from plasma of patients with heterozygous familial hypercholesterolemia and analyzed their ability to promote cholesterol efflux from adipose cells,before and after12weeks of Probucol treatment.2.Materials and methods2.1.Subjects and protocolFour patients with heterozygous familial hyperc-holesterolemia(FH)with mean age of43years(range 30–59)were selected for this study.All patients were classified as familial hypercholesterolemic on the basis of the presence of tendon xanthomas and appropriate family history,and had apo E(3/3)and apo AIV(1/1) phenotypes[14,15].No subject took vitamin E or beta-carotene,or any drug known to affect lipid metabolism. All patients were informed of the purpose of the study, which was approved by an institutional ethics review board.The patients have been treated with Probucol (1000mg daily)for12weeks.Venous blood samples were obtained after an overnight fast.Blood was promptly centrifuged at4°C for15min at3000×g to separate cells from plasma.Samples of plasma were used for analysis of lipids,apolipoproteins and isolation of lipoprotein particles.2.2.Lipoprotein particles isolationHDL particles were purified from total plasma from patients before and12weeks after Probucol therapy,by sequential immunoaffinity chromatography using anti-bodies against apolipoproteins,apo B,apo E,apo AI, apo AII and apo AIV,as previously described[13,16]. This resulted in the isolation of four types of lipo-protein particles:Lp AI,Lp AI:AII,Lp AIV and Lp AI:AIV:AII.To avoid interactions with apo E and apo B/E receptors,apo B-and apo E-containing particles were removed from plasma.As shown in Fig.1,plasma samples were applied consecutively to immunosorbents at theflow rate of10ml/h in Tris buffer.In each case, the immunosorbent was washed with Tris buffer con-taining0.5M NaCl at aflow rate of60ml/h to elute non-specifically bound particles.The retained fraction was eluted with3M sodium thiocyanate(NaSCN)at a flow rate of60ml/h.The eluate was immediately filtered through a column packed with Sephadex G25 to remove the NaSCN from the retained fraction.This procedure minimized the inactivation of LCAT.Fi-nally,all particles were dialyzed against Tris buffer and werefiltered using a0.22-m m Milliporefilter.Fig. 1.Flow diagram of the various stages of sequential im-munoaffinity chromotography resulting in the isolation of the four types of HDL particles named according to their composition in the main apolipoproteins(Apo,apolipoprotein;Lp,lipoprotein;RF, retained fraction;NRF,non-retained fraction).A.Adlouni et al./Atherosclerosis152(2000)433–440435The following lipoprotein particles werefinally ob-tained,Lp AI,Lp AI:AII,Lp AIV and Lp AI:AIV:AII.2.3.Lipids,apolipoproteins and lipoprotein particles analysisTotal cholesterol,triglycerides and phospholipids were determined enzymatically,using kits from Boehringer-Manheim(Germany).The HDL-cholesterol level was determined enzymatically after isolation of HDL by the phosphotungstic acid–magnesium chloride method[17].The LDL cholesterol level was determined using kit a from Biome´rieux(France).Proteins were determined by the method of Lowry [18].Apolipoproteins were measured by specific im-munoassays,using a standard type Elisa as previously described[19].Lp AI was quantified using a differential electroimmunoassay[20].The quantitative determina-tion of Lp AI:AII was performed by enzyme-linked differential antibody immunosorbent assay as described [21].2.4.LCAT and CETP acti6itiesThe LCAT activity of samples of plasma and lipo-protein particles,purified from total plasma from pa-tients before and12weeks after Probucol therapy were measured using the method of Chen and Albers[22]. Proteoliposome substrate containing apo AI,lecithin and[14C]cholesterol-labeled lipoproteins complexes were incubated with20–60m g particle protein in a shaking water bath for5h at37°C.The reaction was stopped by placing samples on ice.Lipids were ex-tracted using CHCl3/CH3OH(2:1,v/v).Esterified[14C] cholesterol and excess labeled substrate were separated by thin-layer chromatography using petroleum benzine/ diethyl ether/acetic acid,and the radioactivity of the bonds was counted.LCAT activity was expressed as a percentage of cholesterol esterified per100m g of protein particle per5h of incubation.Cholesterol ester transfer protein(CETP)activity of the plasma samples from patients before and12weeks after Probucol therapy was measured using the method of Albers et al.[23].CETP activity was evaluated by measuring the transfer of radiolabeled cholesteryl esters from labeled donor to unlabeled acceptor lipoprotein substrates.Briefly,a mixture of20m l of plasma with0.1 mg of a[14C]cholesteryl ester-HDL3donor and0.1mg of an LDL acceptor were incubated at37°C in a shaking water bath for5h.The reactions were stopped by chilling the tubes on ice.Donor and acceptor lipo-proteins were separated by the dextran sulfate-magne-sium chloride precipitation procedure.CETP activity was expressed as percentage of[14C]cholesteryl ester-HDL3transferred per20m l of plasma sample per5h of incubation.2.5.Cellular cholesterol efflux studiesTo promote cholesterol efflux,differentiated cells Ob1771[3]werefirst maintained for48h in lipoprotein-deficient bovine serum at37°C and then exposed to[3H]-cholesteryl linoleate-enriched LDL for48h(150 m g of cholesterol per ml)in the same medium.Subse-quently,cells were washed in0.1M phosphate bufferedsaline(PBS)and maintained in serum-free mediumsupplemented with particles purified from total plasmafrom patients before and12weeks after Probucol ther-apy for various times(50m g of protein particles/ml oronly50m g of dimyristoyl-phosphatidyl choline(DMPC)per ml as a control).Cells were then washedwith PBS at4°C and solubilized in0.1N NaOH.Theremaining cellular cholesterol was then determined byradioactivity counting.The radioactivity appearing inthe medium was a percentage of the initial cell-associ-ated[3H]-cholesterol.2.6.Statistical analysisStatistical analysis was performed using the MannWhitney U-test to evaluate the data.3.Results3.1.Lipid,apolipoprotein and lipoprotein particleconcentrations in plasmaThe results of Table1indicate plasma lipid,apolipo-protein and lipoprotein particle profiles of the patientsbefore and12weeks after Probucol therapy.As alreadyreported[24–28],the actual concentration of lipids,apolipoproteins and lipoprotein particles of this groupshowed a decrease after12weeks of treatment exceptedfor apo AIV and apo E.Total plasma cholesterol andLDL-cholesterol levels decreased by17and14%,re-spectively,while plasma apo B concentrations and theLDL-cholesterol/apo B ratio decreased slightly(7.6and5.8%respectively).Triglycerides were modestly affected(−5.5%).Probucol caused consistent reduction in theHDL-cholesterol levels(−36%).The decline in HDL-cholesterol resulted probably from reductions in apo AI(−34%)and still more in Lp AI(−45%).Lp AI:AIIlevel decreases by20%.Apo E levels increased by68%while that of apo CIII decreased by25%after Probucoltreatment.3.2.Protein,lipid and apolipoprotein compositions ofisolated particlesSequential immunoaffinity chromatography was usedto isolate four subclasses from plasma according totheir major apolipoprotein contents:Lp AI,Lp AI:AII,A .Adlouni et al ./Atherosclerosis 152(2000)433–440436Table 1Plasma concentration of lipids,apolipoproteins and lipoprotein particles before and after Probucol treatment aAfter Probucol treatment P -Value*Before Probucol treatment250926Total cholesterol 0.001300919Triglycerides 144970136973NS 250937NS Phosholipids 2759302692.04191.9B 0.001HDL cholesterol 197925LDL cholesterol B 0.012289246095.09296.0B 0.001Apo AI 2892.0Apo AII 2792.0NS 991.0890.6NS Apo AIV 130913Apo B 120924NS 2.890.6B 0.02Apo CIII 3.790.7 2.790.21.690.9B 0.001Apo E 2294.0B 0.001Lp AI 4199.04096.0B 0.025098.0Lp AI:AIIaValues are expressed in mg /dl and are the mean 9S.D.*Significantly different from before Probucol treatment,P B 0.05.NS,no significant.Table 2Protein and lipid composition (mass %)and apolipoprotein composition (mass %)of isolated lipoprotein particles aLipids ApolipoproteinsProteinTotalTriglyceridePhospholipidAIAIIAIVCIIIcholesterolLp AIBefore Probucol 72.096.8 4.190.3 2.090.622.091.798.090.8Undetectable 1.490.90.390.29.892.1 6.191.8After Probucol 20.092.064.195.698.091.7Undetectable 1.691.30.490.3Lp AI :AII10.093.2 5.791.520.596.265.891.9Before Probucol 32.191.463.896.2 1.891.30.490.111.992.312.294.418.394.961.491.757.593.138.191.7After Probucol 0.2790.10.290.1Lp AIV0.990.3 4.390.8 4.491.3Undetectable 90.093.018.495.4Before Probucol 81.095.30.590.181.294.4After Probucol 3.990.78.090.97.091.5Undetectable 8.893.190.798.10.390.1Lp AI :AIV :AII 4.491.3 4.491.39.390.978.993.781.692.89.894.4Before Probucol 10.695.40.690.17.591.012.495.817.491.3After Probucol58.090.665.694.615.593.126.093.10.690.1aThe protein and lipid composition are given as %mass.The apolipoprotein composition is given by taking as 100%the total apolipoproteins determined by immunoassays.The values are mean 9S.D.of four preparations of each lipoprotein particle.Lp AIV and Lp AI:AIV:AII.Apo E-and Apo B-con-taining particles were first removed,their absence was confirmed by ELISA.Isolated particles were analyzed for their lipid and apolipoprotein composition (Table 2).It appears that protein mass of lipoprotein particles were decreased after Probucol treatment.The repartition in percentage became 64.1,57.5,81.2and 65.6%for Lp AI,Lp AI:AII,Lp AIV and Lp AI:AIV:AII,respectively.These values were approximately similar to those ob-tained in normolipemic subjects [13].The percentage of total cholesterol in Lp AI,Lp AIV and Lp AI:AIV:AII was higher after Probucol treatment.The percentage of triglycerides in isolated particles showed a marked in-crease after Probucol treatment.Apolipoprotein com-positions in Lp AI were unchanged by Probucol therapy.Lp AI contains mainly a single apolipoprotein,as in normolipemic subjects,in which apo AI represents 98%of total mass of apolipoproteins [3,13].Lp AI:AIV:AII was enriched in apo AIV after treatment,while Lp AIV contained less of apo AII.3.3.LCAT and CETP acti 6itiesPlasma LCAT activity was significantly (P B 0.001)increased from 0.7990.2to 3.2890.7%of esterifed cholesterol /15m l of plasma per 30min of incubation after Probucol treatment.A.Adlouni et al./Atherosclerosis152(2000)433–440437Before Probucol treatment,LCAT activity in Lp AI:AII was higher than in Lp AI.The LCAT activity in Lp AI markedly(P B0.001)increased from4.892.0to 2293.0%of esterified cholesterol per100m g protein per5h of incubation after Probucol treatment(Table 3).LCAT activity in Lp AIV was also increased after Probucol treatment but less than in Lp AI(from1.59 0.5to 1.990.6%).However,Probucol treatment in-duces no changes in LCAT activity in Lp AI:AIV:AII. Plasma CETP activity before Probucol treatment, using[14C]cholesteryl ester-HDL3donor and LDL acceptor induced a transfer of7.492.1%of[14C] cholesteryl ester/20m l of plasma per5h of incubation. After Probucol treatment,activity of plasma CETP induced a transfer of21.593.2%of[14C]cholesteryl ester/20m l of plasma per5h of incubation.3.4.Cholesterol efflux from cholesterol preloaded Ob 1771adipose cellsFollowing[3H]cholesterol preloading of adipose cells by means of[3H]cholesteryl linoleate-enriched LDL, the four types of lipoprotein particles isolated before and after Probucol treatment were assayed for their ability to promote cholesterol efflux,as a function of time,at37°C(Table4).Probucol therapy enhances Lp AI and Lp AIV more than Lp AI:AIV:AII to promote cholesterol efflux from adipose cells.In contrast,no efflux from was promoted by Lp AI:AII and the con-trol DMPC liposomes after Probucol treatment.Table 4showed a trend toward greater cholesterol efflux promoting by Lp AI and Lp AIV particles isolated after Probucol treatment.Table3The LCAT activity in isolated lipoprotein particles aBefore Probucol treatment P-Value*After Probucol treatment4.892.0Lp AI2293.0B0.0019.392.1Lp AI:AII B0.0016.392.11.590.5Lp AIV 1.990.60.002NS1.190.6 1.190.4Lp AI:AIV:AIIa Values are in a percentage of cholesterol esterified/m g of protein particles per5h of incubation.Values are the mean9S.D.*Significantly different from before Probucol treatment,P B0.05.Table4Cholesterol efflux from[3H]-Cholesterol-preloaded Ob1771cells before and after12weeks of Probucol treatment a[3H]-cholesterol efflux(percent of initial cell-associated cholesterol)Incubation time(min)After Probucol treatmentBefore Probucol treatment P-Value* Lp AI302694.23594.6B0.0013094.6904094.8B0.001 1804395.04494.9NSLp AI:AII3.090.2NS2.090.3302.090.2 1.090.190NS2.090.2 2.090.2180NSLp AIV2896.1303496.50.002 903697.34097.0B0.054696.84696.7180NS LpAI:AIV:AII2595.1302796.6NS 903495.8NS3695.31804096.04196.2NS Dimyristoyl phosphatidylcholineNS30 3.090.22.090.12.090.1 1.090.190NS2.090.1 2.090.1180NSa The radioactivity appearing in the medium was as a percentage of the initial cell-associated[3H]-cholesterol.Values are mean9S.D.*Significantly different from before Probucol treatment,P B0.05.A.Adlouni et al./Atherosclerosis152(2000)433–440 4384.DiscussionProbucol,the only drug shown to induce xanthoma regression in FH,is a potent antioxidant,but it also lowers HDL-cholesterol levels,causing some concern [24,25].Probucol therapy consistently reduce total and LDL cholesterol levels[6,26–30].The antiatherogenic mechanism of this drug relate to its antioxidant action, preventing the oxidative modification of LDL,which may play a role in the alteration of arterial wall elastic properties[31–33].It has been reported that Probucol is located in apo B and apo A families lipoprotein particles,with a preferential association with apo B-containing lipoprotein particles[34].Recent studies on its distribution have shown that serum concentrations of Probucol are reduced during LDL-apheresis and it is mainly due to reductions in the LDL fraction[35]. The object of this study was the evaluation of Probu-col therapy effect on HDL metabolism based upon their subclasses analysis according to their apolipo-protein composition.We isolated from the plasma the major apo A-containing particles Lp AI,Lp AI:AII,Lp AIV and Lp AI:AIV:AII and analyzed their lipid and apolipoprotein contents,their LCAT and CETP activi-ties and their abilities to promote cholesterol efflux from cholesterol-preloaded adipose Ob17cells.The changes in levels of plasma lipids and apolipo-proteins noted in these patients following Probucol treatment were similar to those previously reported [26–30,36].The greater decrease in both total(17%) and LDL-cholesterol(14%)with a slightly decrease in plasma triglycerides and apo B could be documented in the present study,which is in agreement with previous data[26–30].The nature of the changes in HDL-cholesterol may result in a decrease of apo A-I and Lp AI.In addition,plasma apo E concentration was in-creased after Probucol treatment that is of interest according to the evidence that apo E-HDL interact with the hepatic apo E receptor[37].Our results indicate remarkably that Probucol ther-apy not only reduces plasma LDL and HDL-choles-terol but also induces a marked decrease of plasma Lp AI concentration.The effect on plasma HDL apolipo-protein concentrations was primarily on apo AI(34%), consistent with the dramatic reduction of Lp AI(46%). These results were in agreement with previous reported data[28,38].This observation is of interest considering the lipid-lowering therapeutic effect of Probucol in decreasing plasma HDL2levels[25,29,30].Probucol stimulated CETP activity after12weeks treatment as previously reported[28,30,39].Moreover, the increase of CETP activity was accompanied by a greater decrease of plasma Lp AI level that became large in size and content,and triglyceride-rich particles. It is known that CETP activity is particularly associ-ated with the large Lp AI fraction in normolipemic subjects[40].Thus,the effect of Probucol on CETP activity may occur through alteration of CETP catabolism,or stimulation of CETP synthesis,or with both mechanisms.In normolipemic subjects,plasma LCAT activity was associated primarily with Lp AI(72%),particularly with the large Lp AI fraction that retained54%of the LCAT activity[40].Our study showed an increase of plasma LCAT activity after Probucol treatment and indicated that the low HDL-cholesterol levels associ-ated with Probucol treatment are not a priori evidence of atherosclerosis progression.Isolated particles before Probucol treatment showed a relatively high protein content of total weight as compared to lipoprotein particles isolated from nor-molipemic subjects[13].This shift to smaller,protein-rich lipoprotein particles in our patients is in agreement with the study reported by Cheung et al.[41],in which patients suffering from cardiovascular diseases with elevated plasma cholesterol have protein-rich Lp AI and Lp AI:AII particles.Thus,after Probucol treat-ment protein content of lipoprotein particles reached the values of normolipemic subjects.Previous results indicate that after18months of Probucol treatment, the HDL protein content decreased by56%[42].Saku et al.[43]have reported that the small Lp AI have a higher fractional catabolic rate than the large Lp A-I. So we suggest that the decrease of the Lp AI level following Probucol treatment may be the result of the decrease of small Lp AI by an enhancement of its fractional catabolic rate and increase of large Lp AI. This change in lipoprotein particle size observed after Probucol treatment may be more active functionally in reverse cholesterol transport.Thus,we suggest that the HDL cholesterol levels following Probucol treatment may reflect increased reverse cholesterol transport. With respect to lipid composition,our results show that lipoprotein particles have indeed more lipid con-tent after the treatment than before.The isolated Lp AI after Probucol treatment was characterized by higher cholesterol content than the one isolated before Probu-col treatment.This result is in agreement with the results reported by Franceschini et al.[30],in which a 44%increase of cholesterol in HDL2after Probucol treatment has been found.Interestingly enough and most remarkably,Probucol treatment induces an en-hancement of LCAT activity in Lp AI(4.5-fold).In normolipemic subjects LCAT activity in plasma was particularly associated with the large Lp AI fraction [40].Before Probucol treatment,LCAT activity in Lp AI was lower than in Lp AI:AII.It was shown that in normolipemic subjects,LCAT activity in Lp AI:AII was higher than in small Lp AI[40].After removing free cholesterol by apo AI-containing lipoprotein particles,it may be esterified by LCAT and the esterified cholesterol is rapidly exchanged by triglyc-A.Adlouni et al./Atherosclerosis152(2000)433–440439erides.So,isolated particles after Probucol treatment contained more triglycerides than those isolated before the treatment.The initial step of reverse cholesterol transport con-sists of cholesterol transfer from the cell surface to accepting particles.The cell-derived cholesterol is rapidly transferred to small HDL particle,pre-beta-1 [44].It has been suggested that this particle initially accepts peripheral cell free cholesterol and subsequently transports it to larger HDL that contain LCAT where it can be esterified and transfered to LDL[45]. Isolated particles of Lp AI:AIV:AII after Probucol treatment showed a slight cholesterol effluxing capacity. However,isolated particles Lp AI and Lp AIV after Probucol treatment showed a trend toward greater cholesterol efflux than isolated particles before Probu-col treatment.No efflux was promoted by Lp AI:AII before and after Probucol treatment.This is of with reference to the previous studies that have demon-strated a close correlation between the extent of xan-thoma regression and HDL reduction[8,46].In addition,Goldberg and Mendez[47]observed an en-hancement of the HDL-mediated cholesterol efflux from cultured human skinfibroblasts incubated with Probucol.Based on the results of lipoprotein particle character-ization,LCAT and CETP activities and cholesterol efflux from cholesterol-preloaded Ob1771adipose cells, we confirm the hypothesis that,in addition to an antioxidant effect of Probucol,the decrease in HDL-cholesterol may not be an atherogenic change,but in contrast may reflect a favorable change for HDL metabolism.This change caused by Probucol acceler-ate,cholesterol transport through HDL system,pro-moting reverse cholesterol transport from peripheral tissues.Probucol has been reported to regress atherosclerosis in animal models and to diminish tendinous xanthomas in man.The presentfindings suggest that lowering LDL-cholesterol levels,activation of reverse cholesterol transport process,and antioxidant effects of Probucol may cause an antiatherogenic action.References[1]Miller GJ,Miller NE.Plasma high-density lipoprotein concen-tration and development of ischemic heart ncet 1975;i:16–9.[2]Gordon T,Castelli WP,Hjortland MC,Kannel WB,DawberTR.High density lipoprotein as protective factor against coro-nary heart disease:the Framingham study.Am J Med 1977;62:707–14.[3]Barkia A,Puchois P,Ghalim N,Torpier G,Barbaras R,Ail-haud G,Fruchart JC.Differential role of apolipoprotein AI-con-taining particles in cholesterol efflux from adipose cells.Atherosclerosis1991;87:135–46.[4]Barter P.High-density lipoprotein and reverse cholesterol trans-port.Curr Opin Lipidol1993;4:210–7.[5]Barnhart JW,Sefranka JA,Mc Intosh DD.Hypocholesterolemiceffect of4,4%-(isopropylidenedithio)bis(2,6-di-t-bytylphenol) (Probucol).Am J Clin Nutr1970;23:1229–33.[6]Zimetbaum P,Eder H,Frishman WJ.Probucol:pharmacologyand clinical application.Clin Pharmacol1990;30:3–9.[7]Kuzuya M,Kuzuya F.Probucol as an antioxidant and an-tiatherogenic drug.Free Radic Biol Med1993;14:67–77.[8]Matsuzawa Y,Yamashita S,Funahashi T,Yamamoto A,TuruiS.Selective reduction of cholesterol in HDL2fraction by Probu-col in familial hypercholesterolemia and hyper HDL2choles-terolemia with abnormal cholesteryl ester transfer.Am J Cardiol 1988;62:66–72.[9]Rader DJ,Castro G,Zech LA,Fruchart JC,Brewer HB Jr.Invivo metabolism of apolipoprotein A-I on high density lipo-protein particles Lp(AI)and Lp(AI–AII).J Lipid Res 1991;32:1849–59.[10]Ohta T,Nakamura R,Ikeda Y,Shinohara M,Miyazaki A,Horiuchi S,Matsude I.Differential effect of subspecies of lipo-protein containing apolipoprotein A-I on cholesterol efflux from cholesterol-loaded macrophages:functional correlation with lecithin cholesterol acyltransferase.Biochim Biophys Acta 1992;1165:119–28.[11]Puchois P,Kandoussi A,Fievet P,Fournier JL,Bertrand M,Koren M,Fruchart JC.Apolipoprotein AI containing lipo-proteins in coronary artery disease.Atherosclerosis1987;68:35–40.[12]Fielding CJ,Fielding PE.Evidence for a lipoprotein carrier inhuman plasma catalyzing cholesterol efflux from culturedfibrob-lasts and its relationship to lecithin:cholesterol acyl transferase.Proc Natl Acad Sci USA1981;77:3911–4.[13]Duverger N,Ghalim N,The´ret N,Fruchart JC,Gastro G.Lipoproteins containing apolipoprotein AIV:composition and relation to cholesterol esterification.Biochim Biophys Acta 1994;1211:23–8.[14]Sing CF,Davignon J.Role of the apolipoprotein E polymor-phism in determining normal plasma lipid and lipoprotein varia-tion.Am J Hum Genet1985;37:268–85.[15]Menzel HJ,Kovary PM,Assman G.Apo AIV polymorphism inman.Hum Genet1982;62:349–52.[16]Ghalim N,Adlouni A,Saı¨le R,Parra HJ,Benslimane A,BardJM,Fruchart JC.Apolipoprotein AIV of human interstitialfluid is associated to apo AI-containing lipoprotein particles but not to apo AII-containing particles.Int J Clin Lab Res1996;26:224–8.[17]Assman G,Schriewer H,Schmitz G,Hogle EO.Quantificationof high-density lipoprotein cholesterol by precipitation with phosphotungstic acid/MgCl2.Clin Chem1983;29:2026–30. [18]Lowry OH,Rosebrough NJ,Farr AL,Randall RJ.Proteinmeasurement with the folin phenol reagent.J Biol Chem 1951;193:265–70.[19]Fruchart JC,Fievet C,Puchois P.Apolipoproteins.In:Bergneyer HU,editor.Methods of Enzymatic Analysis,vol.III.New York:Academic Press,1985:126–35.[20]Parra HJ,Mezdour H,Ghalim N,Bard JM,Fruchart JC.Differential electroimmunoassay of human Lp AI lipoprotein particles on ready-to-use plates.Clin Chem1990;36(8):1431–5.[21]Koren E,Puchois P,Alaupovic P,Fesmire FM,Kandoussi A,Fruchart JC.Quantitative determination of two different types of apo AI-containing lipoprotein particles in human plasma by enzyme-linked differential antibody immunosorbent assay.Clin Chem1987;33:38–43.[22]Chen C,Albers JJ.Characterization of proteoliposomes contain-ing apolipoprotein AI:a new substrate of the measurement of lecithin:cholesterol acyltransferase activity.J Lipid Res 1982;23:680–91.。

小学上册英语第一单元测验试卷英语试题一、综合题(本题有50小题，每小题1分，共100分.每小题不选、错误，均不给分)1 ssance artist Michelangelo is famous for painting the _____. The Rena2 My sister is a ______. She enjoys baking cookies.3 The candy is _____ (sweet/sour).4 The _____ (狐狸) is a master of stealth.5 What is the capital of Somalia?a. Mogadishub. Hargeisac. Kismayod. Baidoa答案:a6 What do you call a baby elephant?A. CalfB. CubC. KidD. Foal7 My favorite color is ________ because it makes me happy.8 Kittens are baby _________ (猫).9 The _____ (花环) made of fresh flowers is beautiful.10 What is the name of the largest ocean on Earth?A. Atlantic OceanB. Indian OceanC. Arctic OceanD. Pacific Ocean答案: D. Pacific Ocean11 I often share my toy experiences with my ________ (名词) to inspire them.12 An earthquake's effects can be measured using a ______ scale.13 The __________ is where most plant and animal life exists.14 A lizard can lose its ______ (尾巴) to escape.15 What is the main color of a polar bear?A. BrownB. WhiteC. BlackD. Gray答案:B16 I like to listen to ________ (流行歌曲) on the radio.17 What is 14 7?a. 5b. 6c. 7d. 8答案:b18 My dad is a __________ (医疗工作者).19 What do we wear on our feet?A. HatB. SocksC. GlovesD. Scarf答案:B20 What is the largest planet in our solar system?A. EarthB. MarsC. JupiterD. Saturn答案:C21 The _____ (植物群落) can vary greatly from one region to another.22 The sky is ________ (晴朗) today, let's go outside!23 What is the name of the national flower of Japan?A. RoseB. Cherry BlossomC. LotusD. Sunflower答案:B24 The garden is alive with colorful _______ and buzzing insects.25 The _______ of a solution is how concentrated it is.26 We will _____ (play/study) after school.27 I enjoy drawing and coloring pictures of my ________ (梦想) and interests.28 She is wearing a lovely ___. (dress)29 The dog fetches the _______ (狗捡回_______).30 The unit of measurement for temperature is __________.31 The ______ (植物的生长环境) affects their characteristics.32 ts are known for their ______, which can be used in crafts. (某些植物因其纤维而闻名，可以用于手工艺。

小学上册英语第四单元真题(含答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What do you call the main character in a story?A. AntagonistB. ProtagonistC. Supporting CharacterD. Narrator答案: B2.The ______ (生态) plays a role in the survival of many species.3.I enjoy crafting gifts for my friends and family, such as __________.4.My favorite color is ______ (蓝色). It reminds me of the clear ______ (天空).5.The ______ is a measure of how much matter is in an object.6.Which season is known for blooming flowers?A. WinterB. SpringC. SummerD. Autumn答案: B7.We can find many ________ (植物) in the rainforest.8.The doctor, ______ (医生), gives advice on staying healthy.9.小猴子) eats bananas all day. The ___10.__________ are used to represent elements in the periodic table.11.I call my neighbor ______ when I see him. (我见到我的邻居时称他为)12.What is the capital of the United States?A. New YorkB. Washington, D.C. C. Los AngelesD. Chicago答案:b13.The capital of Barbados is __________.14.n Tea Party was a protest against _____. The Bost15. A gazelle is known for its speed and ______ (优雅).16.What is the name of the famous river that runs through Egypt?A. AmazonB. MississippiC. NileD. Yangtze答案: C. Nile17.The __________ (历史的教训) is invaluable.18.The Earth's magnetic field protects us from ______.19.The sky is _______ (非常晴朗).20.The __________ is a famous city known for its historic buildings. (伊斯坦布尔)21.The _____ (ancient) Romans built roads that connected their empire.22.My sister is a ______. She enjoys singing.23.What is the process of taking in oxygen called?A. InhalationB. ExhalationC. RespirationD. Digestion答案: A24.The puppy is very ________.25.Listen and number.(听录音标号.)26.Enzymes are biological ______ that speed up reactions.27.The __________ is famous for its cherry blossoms.28.The dog is ______ with a ball. (playing)29.What do you call a place where animals are kept for public display?A. FarmB. ZooC. ParkD. Aquarium答案: B30.The __________ is a region known for its deserts.31.We will go ______ for a picnic tomorrow. (outside)32.We like to listen to ___. (music)33.I enjoy painting ________ (水彩画) in art class.34.What do we call the act of keeping something safe from harm?A. ProtectionB. PreservationC. ConservationD. Safeguarding答案: A35.The chemical symbol for neon is _______.36.I like to ________ my friends.37.My sister is _______ (在画画).38.We have English class _____ (on/in) Tuesday.39.The _____ (狐狸) is clever and quick on its feet.40.Elements are organized in the periodic ______.41.The rabbit’s ears help it hear _______ (声音).42.My favorite dish is ______ (意大利面).43.Fish come in many _________. (颜色)44. A __________ is a mixture that can be separated by centrifugation.45.在历史上，________ (battles) 常常改变了国家的命运。

高分子吸水树脂（Superabsorbent polymer）Super absorbent polymers because it has a large amount of water, many properties, water retention ability and the polymer such as mechanical properties, plasticity, easy processing and convenient use, development in recent twenty years, and is widely used in disposable sanitary products, agricultural areas, photoelectric cable industry and waterproofing industry.Disposable hygiene products are super absorbent polymers is also more mature applications, accounting for the total amount of super absorbent polymer, 70%-80%, is the main infant health care products, health care supplies and adult incontinence women health supplies. Because the product is not a simple solution, it contains a mixture of salt, minerals, and blood. Therefore, we use physiological saline and artificial blood plasma to test the high polymer water absorbent resin and diaper pants, which is more in line with the actual conditions.Urine pants technical requirementsDiaper is an absorbent core made of wood pulp and macromolecule absorbent resin, and it is composed of no cloth, paper towel, elastic band and adhesive. The demand for diaper pants is that the baby wears no leakage, water absorption and water retention, and makes the baby's skin dry and comfortable. The performance requirements of diaper pants manufacturer mainly include water retention, penetration rate, liquid diffusion and leak proof. The raw materials for each diaper diaper on the performance of the contribution is different, such as the surface layer of fine cloth to wear diversion infiltration velocity, the liquiddiffusion range of relatively large impact, and super absorbent polymer, urine trousers to rewet performance have a relatively large impact, about 70% of the contribution from the absorption resin.Properties of high polymer water absorbent resinThe emergence of super absorbent polymers led to diaper use and production of the revolution, due to its high water absorption and good water retention properties of the modern disposable diaper convenient but also to bring the baby dry and comfortable for the mother widow.As a raw material of urine trousers, macromolecule water absorbent resin has many characteristics, such as absorption rate, absorption capacity, absorption under pressure and water holding capacity.Absorption rate: it shows the maximum absorption capacity of high polymer water absorbent resin at a certain period of time. The general data is the physiological salt which can be absorbed by 1g macromolecule absorbent resin at the beginning of 30s, 60s or 180s.Absorption capacity: it shows the maximum amount of physiological salt absorbed by 1g macromolecule absorbent resin.Absorption capacity under pressure (0.70pa): it shows the maximum absorption capacity of 1G superabsorbent resin under the condition of 0.7pa pressure. This is because babies aresitting or lying in many situations, when urine is often absorbed under the pressure of the human body. This test is designed to simulate and understand the absorption of an absorbing resin under pressure.Water retention: it shows that the maximum amount of normal saline can be maintained by the 1400 centrifugal treatment after the absorption of the largest amount of normal saline in the 1g macromolecule absorbent resin. It indicates that the high absorption resin can really keep up with a fixed amount of normal saline.Specific gravity and particle distribution: it shows the specific gravity, particle size and distribution of high polymer water absorbent resin.There are different characteristics on the performance contribution of these pants, so we do not believe that a high data is certainly a good product, but relatively speaking, the amount of water retention and absorption under pressure is more important.Effect on diaper performance:With regard to the requirements of diaper pants and the role of polymeric absorbent resins in urine pants, the water absorption and the amount of absorption under pressure are important. Followed by water absorption rate and water absorption. Now the diaper industry, whether manufacturers or diaper pants are very concerned about the distribution of water absorption rate, that diaper absorbent fast pants is good,especially the diaper manufacturers will be water absorption rate as the only standard of water absorbent resin quality, the diaper development produced a misleading, so our pants can not keep up with the world advanced diaper development trends timely. Our analysis of urine pants chip, we can find that there are two kinds of raw materials: high polymer water absorbent resin and wood pulp.A tree with high absorbent polymer water absorption and high water absorption quantity characteristics, water absorption and water retention and it is dozens of pulp and wood pulp, together with good dispersion effect of capillary, guide high water absorption rate, which is about 5-6 of polymer water absorbent resin. Therefore, the performance of both of them is complementary, and the appropriate ratio and mixture of urine trousers chip can achieve the best absorption rate and water retention effect. If our greatest concern is the rate, then the wood pulp will be the best raw material for trouser chips. While we use the diaper and focus on the promotion of publicity is to keep the baby buttocks skin dry, high water absorbent polymer resin with water retention and to ensure the characteristics of industrialization, it is a water absorbent resin can become the main reason for the new generation of diaper material.In order to understand the relationship between the polymer water absorbent resin and water absorption rate, we use the test method of column shaped water absorbent polymer water absorbent resin of different tested, we found that the initial absorption rate of super absorbent polymers rapidly after a very short time, it has no absorption of growth, which is to produce Polymer Gelling vaginal septum problems. Macromolecule water absorbentresin is a kind of macromolecule polymer whose surface is cross-linked to some extent. When it absorbs the liquid particles and the rapid expansion of the decline in mechanical strength, and surface adhesive paste produced, if the surface adhesion is serious with each other will have to stop liquids have absorbed and expanded particle gap, the absorption rate tends to stagnate, long-term absorption ability of the polymer water absorbent resin and multiple absorption ability will have a big problem. Mainly in the diaper it second times and third times of infiltration will be relatively high, the first time it can only absorb the baby's urine, after 2-3H baby again after urination will because cementing vaginal septum of the absorption is not smooth, so we can not guarantee the diaper baby's skin dry and lose its true synergistic effect. So, we can not pay too much attention to the absorption rate in the choice of super absorbent polymers, the absorption rate is not higher on the diaper is better, but compared to the diaper market segment to choose a different polymer water absorbent resin suction water retention and under pressure, the design requirements and achieve the diaper in reasonable with pulp and surface layer and other raw materials under.。

作者简介:姚新建(1965-),男,河南省扶沟县人,副教授,硕士,从事高分子化学教学与研究,E -mail :yaoxinjian @sohu 1com收稿日期:2008207230淀粉制取高吸水树脂的研究姚新建,张保东,陈　康,霍俊杰(周口师范学院化学系,河南周口　466000) 摘　要:利用淀粉为原料,与丙烯酸接枝共聚制备了高吸水性树脂,考察了糊化温度、聚合反应时间、丙烯酸单体中和度等因素对接枝产物吸水性能的影响,并比较了吸自来水、蒸馏水及盐水情况。

关键词:淀粉;丙烯酸;接枝共聚;吸水性树脂 中图分类号:TQ 32214 文献标识码:A 文章编号:167129905(2008)1220012203 吸水树脂是一种含有羧基、羟基等强亲水基团并且呈三维交联网状结构的功能性高分子聚电解质材料[1]。

它具有吸收比自身重几百到几千倍水的高吸水功能,且保水性能优良,而在周围环境缺水的条件下,又可将水缓慢释放出来,因此在农业、园林、医药、卫生、沙漠治理、通信电缆、建筑等领域具有广泛的用途[2]。

淀粉系列的高吸水树脂是研究开发最早的,由于原料来源广泛,价格低廉,在自然界中可生物降解,对环境友好,成为吸水树脂领域的研究重点。

本文利用淀粉为原料,与丙烯酸接枝共聚制备了高吸水性树脂。

1　实验部分111　试剂与仪器淀粉(化学纯)、丙烯酸(分析纯,经减压蒸馏处理)、过硫酸钾(分析纯,经重结晶提纯)、氢氧化钠(分析纯)、N ,N 2亚甲基双丙烯酰胺(化学纯)、甲醇(分析纯)。

电热恒温水浴锅、电热鼓风干燥箱、JJ -2增力电动搅拌器。

112　吸水树脂的制备在装有恒速搅拌器装置、冷凝管、温度计的三颈瓶中,加入适量淀粉和一定量的水,在一定温度下糊化,降至室温。

用一烧杯称取适量丙烯酸,用氢氧化钠溶液中和至设定中和度,冷却后加入到三颈瓶中,加入引发剂,搅拌、升温、反应,将反应产物冷却、洗涤、抽滤、真空干燥,得产品。

113　吸水倍率的测定称取干燥后的吸水树脂,放入过量的去离子水中,充分溶胀吸水后,称重量。

Effect of supercritical CO 2on phase structure of PEO/PVAc blendsevaluated from SAXS absolute intensity measurementYeong-Tarng Shieh a,*,Yen-Gu Lin a ,Hsin-Lung Chen baDepartment of Chemical Engineering,National Yunlin University of Science and Technology,123University Road,Section 3,Touliu,Yunlin 640,Taiwan,ROCbDepartment of Chemical Engineering,National Tsing Hua University,Hsin-Chu 300,Taiwan,ROCReceived 11December 2001;received in revised form 25February 2002;accepted 27February 2002AbstractThe effect of supercritical CO 2on the morphological structure of crystalline/amorphous PEO/PVAc blends was investigated by means of SAXS with the measurement of absolute scattering intensity.The morphological structure of PEO/PVAc exhibited a considerable change upon CO 2treatment as demonstrated by the drastic increase of scattering intensity,or the enhancement of electron density contrast between the crystalline and amorphous layers in the lamellar stacks,resulting from the swelling of amorphous PEO via the incorporation of CO 2into the interlamellar (IL)regions and/or the expulsion of PVAc from the IL regions.Upon CO 2treatment,the crystal and amorphous layer thickness (l c and l a ,respectively)were both pared with the increase of l a ,the increase of l c was relatively signi®cant and was attributed to the occurrence of melting and recrystallization during CO 2treatment leading to thicker PEO crystals via a depression of equilibrium melting temperature and/or an increase of crystal fold surface free energy.The measured electron density contrast revealed that the distance of segregation in PEO/PVAc blends involved the extralamellar segregation before CO 2treatments and the swelling of inter-lamellar region dominated the drastic increase of scattering intensity after CO 2treatments.The ®nding of extralamellar morphology was consistent with the magnitude of volume fraction of lamellar stacks in the blends.The lamellar size distribution appeared to be broader and the lamellar stacks more disorganized for the blends after CO 2treatments according to SAXS one-dimensional correlation function pro®les.q 2002Elsevier Science Ltd.All rights reserved.Keywords :Crystallization;Phase segregation;Lamellar1.IntroductionCrystallization of a melt-miscible crystalline/amorphous blend involves the segregation of amorphous diluent.Depending upon the distance of segregation,various types of morphology may be created.These segregation types include (1)interlamellar (IL)segregation,where segrega-tion of the diluent occurs at lamellar level,so that the diluent is located in the IL regions;(2)inter®brillar (IF)segrega-tion,where the diluent is segregated by a larger distance to the regions between the lamellar bundles in spherulites;and (3)interspherulitic (IS)segregation,where the diluent is segregated by the largest distance to the regions between spherulites [1,2].The latter two types characterized by the longer segregation distance are also termed as `extralamel-lar segregations'.These morphological patterns represent the diluent dispersion from nanoscopic scale for IL segrega-tion to micrometer scale for IS segregation.Different scales of segregation may lead to different properties.A blend system does not necessarily exhibit only one type of morphology.Different types of morphology may coexist leading to multiple locations for the amorphous diluent [3±7].Keith and Padden [8]suggested that the distance over which uncrystallizable diluent may be segregated is determined by the interplay between the diffusion coef®-cient (D )of impurity molecules and the crystal growth rate (G ).If the diffusion of diluent is relatively slow compared to the crystal growth,the diluent molecules may be trapped inside the IL regions.If diluent diffusion is faster,on the other hand,extralamellar segregation is generated.The interplay between D and G is de®ned by the parameter,d D =G :d has the unit of length and thus provides a quali-tative measure of segregation distance.d may depend on the composition,temperature,molecular weight,and polymer±polymer interaction of the blend.Poly(ethylene oxide)(PEO)/poly(vinyl acetate)(PVAc)Polymer 43(2002)3691±36980032-3861/02/$-see front matter q 2002Elsevier Science Ltd.All rights reserved.PII:S0032-3861(02)00190-8/locate/polymer*Corresponding author.Tel.:1886-5-534-2601;fax:1886-5-531-2071.E-mail address:shiehy@.tw (Y.-T.Shieh).crystalline/amorphous blends have been known to be compatible by both theoretical prediction and experimental results[9±16].Segregation morphology of PEO/PVAc blends has been studied.Martuscelli and Silvestre and coworkers[11,12]examined the segregation morphology by small angle X-ray scattering(SAXS)and found that PVAc was incorporated into the IL regions of PEO crystals. Segregation of the amorphous diluent was found to strongly depend on T g and molecular weight[17].Runt and co-workers[18]found that segregation of the weakly interact-ing polymer pairs(e.g.PEO/poly(methyl methacrylate) (PMMA)and PEO/PVAc)was largely dependent on glass transition temperatures(T g)of the amorphous diluent.The high-T g diluent(e.g.PMMA)was found to reside exclusively in IL regions whereas the low-T g diluent(e.g. PVAc)was excluded at least partially into IF regions.The introduction of strong intermolecular interactions between the crystallizable and amorphous components resulted in signi®cantly reduced crystal growth rates and promoted diluent segregation over greater length scales,regardless of diluent mobility at the crystallization temperature. Although diluent mobility contributed to diluent segrega-tion,the growth of the PEO crystals,and the factors that in¯uenced the growth rate,dominated the length scale of diluent segregation.SAXS has been a powerful tool for probing the detailed microstructure of crystalline/amorphous blends in our previous reports[19±24].The morphological parameters in the lamellar level such as the long period(L),crystal layer thickness(l c),and amorphous layer thickness(l a)can be deduced from the one-dimensional correlation function or the interphase distribution function.Close examination on the composition variation of l a may reveal the existence of IL segregation[25±27].The volume fraction of lamellar stacks(f s)given by the ratio of volume fraction of bulk crystallinity(f c)to the volume fractional crystallinity within the lamellar stacks(f cs),i.e.f s f c=f cs;could serve as a measure for the extent of IL segregation[24]. When the absolute scattering intensity is available,the perturbation of intensity upon blending or treatment may be connected with the change of phase structure of crystal-line/amorphous blends.Supercritical CO2¯uids or compressed CO2gases or liquids have recently drawn much attention because the environmentally friendly CO2(especially the supercritical state CO2)is a potential candidate to be an alternative to substitute for organic chemicals used in modi®cation and processing of polymers,such as being used as a foaming agent to prepare microcellular foams[28±31],a processing aid to reduce melt viscosity in injection molding[32±35],a nucleating agent to induce crystallization[36±38].Upon treatment of the supercritical¯uids,the phase structure of polymers may be perturbed and hence the properties could be modi®ed accordingly;it is thus important to reveal the effect of supercritical CO2on the phase structure of a polymer before the supercritical CO2can be practically used in applications of the polymer.In the present study, we probe the morphological structure of crystalline/amor-phous PEO/PVAc blends treated by supercritical CO2by means of SAXS.It will be seen that the morphological structure of PEO/PVAc exhibits a signi®cant change upon CO2treatment as demonstrated from the drastic perturbation of scattering intensity.In addition,with the absolute inten-sity,the electron density contrast between the crystalline and amorphous layers in the lamellar stacks can be evalu-ated very conveniently from the simple geometric analysis of the correlation function proposed by Strobl and Schneider [39].The measured electron density contrast will be used to investigate the effect of supercritical CO2on the phase structure of crystalline/amorphous PEO/PVAc blends.2.Experimental section2.1.Materials and sample preparationsPEO with M v 900;000was acquired from Aldrich Chemical Company(Milwaukee,WI)and PVAc with M w 104;000and M w=M n 2:0was obtained from Chang Chun Plastics Corporation(Taipei,Taiwan). Uniform®lm samples of neat PEO or its blends with PVAc were prepared by dissolving0.2g neat PEO or the blends in15ml chloroform,followed by casting and drying at room temperature for2days.Specimens for CO2 treatments were ca.0.3mm thick.2.2.CO2TreatmentsThe CO2treatments were performed in a supercritical extractor supplied by ISCO(Lincoln,Nebraska)with a model SFX2±10which was equipped with a syringe pump with a model260D.The polymer®lms for the CO2 treatments were put in a10cm3cell located inside the extractor pressurized by the equipped syringe-type pump at5000psi and controlled at328C.The treatment time was1h.A preliminary test showed that1h of treatment time was able to reach the equilibrium solubility of CO2 in the®lm sample.After the treatment,the cell was depres-surized to ambient pressure in less than20s.The sample after the CO2treatment showed a negligible weight change, indicating that neither CO2resided inside the®lm sample nor any part of the sample was dissolved away.The uniform PEO and PEO/PVAc®lms looked translucent and colorless before CO2treatments but turned into an opaque,milk white,collapsed®lm upon CO2treatments.The change in ®lm appearance indicated that the melting and recrystalliza-tion of PEO had occurred upon CO2treatments.2.3.Bulk crystallinity measurementsVolume fraction of bulk crystallinities(f c)of semicrys-talline PEO/PVAc were calculated from mass fraction of bulk crystallinity(v c)which was determined by dividingY.-T.Shieh et al./Polymer43(2002)3691±3698 3692the heat of fusion of a sample by the heat of fusion of perfectly crystalline PEO.The heat of fusion in J/g of a sample was measured by a differential scanning calorimeter (DSC 2010)of TA Instruments (New Castle,DE).The heat of fusion of perfectly crystalline PEO is 205J/g [40].2.4.SAXS measurementsAll SAXS measurements were performed at room temperature.The X-ray source was operated at 200mA and 40kV and was generated by a 18kW rotating anode X-ray generator (Rigaku)with a rotating anode Cu target.The incident X-ray beam was monochromated by pyrolytic graphite and a set of three pinhole inherent collimators was used so that the smearing effects inherent in slit-collimated small-angle X-ray cameras can be avoided.The sizes of the ®rst and second pinhole are 1.5and 1.0mm,respectively,and the size of the guard pinhole before the sample is 2.0mm.The scattered intensity was detected by a two-dimensional position sensitive detector (Ordela Model 2201X,Oak Ridge Detector Laboratory Inc.)with 256£256channels (active area 20£20cm 2with ,1mm resolution).The sample to detector distance is 4000mm long.The beam stop is around lead disk of 18mm in diameter.All data were corrected by the background (dark current and empty beam scattering)and the sensitivity of each pixel of the area detector.The area scattering pattern has been radially averaged to increase the ef®ciency of data collection compared with one-dimensional linear detector.Data were acquired and processed on an IBM-compatible personal computer.3.Results and discussionFrom DSC measurements for T g of the PEO/PVAc blends prepared by solution casting from chloroform,a single composition-dependent T g is identi®ed over the entire composition range,indicating that PEO is miscible with PVAc in the amorphous region.The T g of the blend is between those of pure PEO and PVAc being 265and 328C,respectively,and increases with increasing PVAc content.The composition variation of T g of the PEO/PVAc blends suggests that the amorphous regions of the blends are rubbery at the 328C of CO 2treatment tempera-ture in this study.Fig.1shows the Lorentz-corrected SAXS pro®les of neat PEO and its blends with PVAc prior to supercritical CO 2treatments.The scattering intensity decreases with increas-ing incorporation of PVAc due to decreasing electron density contrast D h h c 2h a between the crystalline and amorphous layers.The electron densities of crystalline PEO,amorphous PEO,and PVAc calculated from their mass densities (1.24,1.12,and 1.19g/cm 3,respectively)are 0.676,0.612,and 0.636mol/cm 3,respectively.The scattering intensity contrast decreases with increasing PVAc content,suggesting that the electron density of theIL regions is increased due to incorporation of PVAc into IL regions,as this would decrease the electron density contrast between the crystalline and amorphous layers.A second-order peak near q 0.32nm 21can be roughly identi®ed,indicating that a fairly well lamellar stacking in the samples.Fig.2compares the Lorentz-corrected SAXS pro®les of the samples between before and after supercritical CO 2treatments.Neat PEO and the blends after CO 2treatmentsY.-T.Shieh et al./Polymer 43(2002)3691±36983693Fig.1.Lorentz-corrected SAXS pro®les of neat PEO and its blends with various amount of PVAc before CO 2treatments.Fig.2.Lorentz-corrected SAXS pro®les of PEO/PVAc 100/0,90/10,80/20,and 70/30.In each graph,rectangular and triangular symbols stand for samples for before and after CO 2treatments,respectively.apparently show much stronger scattering intensity than those before CO 2treatments due to an increased electron density contrast between the crystalline and amorphous layers caused by the supercritical CO 2.For neat PEO the scattering intensity is increased upon CO 2treatment suggesting that the electron density of amorphous PEO in the IL regions is decreased due to decreasing mass density through the swelling by CO 2,as this would increase the electron density contrast between the crystalline and amor-phous layers.This suggestion is based on the observation of appearance of the sample changing from a uniform,trans-lucent,and colorless ®lm to a collapsed,opaque,and milk white ®lm upon CO 2treatments due to the presence of voids in the CO 2treated sample.These voids include big and small ones.Big voids existing outside the lamellar stacks are apparently responsible for the milk white appearance for samples whereas small voids existing in the IL regions are responsible for the drastic increase of SAXS intensity and would disorganize the lamellar stacks as will be demon-strated later by the one-dimensional correlation function pro®les in Fig.7.For the blends upon CO 2treatment,the enhanced scattering intensity may be somewhat due to the expulsion of PVAc from the IL regions in addition to the swelling effect as described earlier,since the electron density of PVAc is higher than that of amorphous PEO and hence the expulsion of PVAc from IL regions would increase the electron density contrast between the crystalline and amorphous layers of the lamellar stacks.The inference of the expulsion of PVAc from IL regions is based on infrared spectroscopy evidence that the carbonyl groups in PVAc exhibit speci®c interactions with CO 2of Lewis acid-base nature [41].These interactions might give rise to the expul-sion of PVAc from IL regions during depressurizing of CO 2.The weight-average long period associated with the lamellar stacks can be calculated from the peak maximum of the Lorentz-corrected SAXS pro®les using the Bragg's equation,L 2p =q max :Fig.3shows the composition variation of long period for the blends before and after CO 2treatments.The long periods of neat PEO and theblends before CO 2treatments exhibit a roughly constant value at near 39nm with an insigni®cant composition dependence.The long periods for samples after CO 2treat-ments exhibit a signi®cantly increased long period falling in the range 56±62nm depending on the blend composition.In the lamellar stack model with sharp phase boundary,the long period represents the sum of the crystal thickness (l c )and the amorphous layer thickness (l a ).Rise in long period may thus stem from the thickening of crystal layer or the swelling of amorphous layer.Two approaches may be utilized to determine the average thickness of the two layers,namely,the one-dimensional correlation function and the interphase distribution function.The one-dimensional correlation function was utilized to deconvolute long period into the thickness of these two types of layers.The correla-tion function,K z ;de®ned by Strobl and Schneider,adopts the following form [39]:K z 12p 2 10I q q 2cos qz d q 1 where I q is the absolute scattering intensity obtained from the SAXS measurement,q 4p =l sin u =2 (u scattering angle),and z is the direction along which the electron density is measured.K z is different from the correlation function,g z ;de®ned by Vonk,where normalization by the invariant was introduced for g z [42,43].Since the experimentally accessible q range is ®nite,extrapolation of intensity to both low and high q is necessary for the integrations.Extrapolation to zero q was accom-plished by the Debye±Bueche model [44,45],I q A11a 2c q2ÀÁ22where A is a constant and a c is the correlation length.A anda c can be determined from the plot of I q 21=2vs.q 2using the intensity data at low q region.Extension to large q can be performed using the Porod±Ruland model [46],I q K p exp 2d 2q 2q 41I fl3where K p is the Porod constant,d is a parameter related to the thickness of crystal/amorphous interphase,and I ¯is the background intensity arising from thermal density ¯uctua-tion.The values of K p ,d ,and I ¯were obtained by curve ®tting the intensity pro®le at high q region.Fig.4shows the representative plot of K z :Assuming the corresponding two-phase model,l c and l a can be estimated via simple geometric analysis of K z :The thickness of the thinner layers (l 1)is given by the intersection between the straight line extended from the self-correlation triangle and the baseline given by 2A .The average thickness of the thicker layer is then given by l 2 L 2l 1:The assignment of l 1and l 2is governed by the magnitude of the linear crys-tallinity within the lamellar stacks (f cs ),where f cs l c = l c 1l a :When f cs ,0.5,the crystals contribute to theY.-T.Shieh et al./Polymer 43(2002)3691±3698position variation of long period of semicrystalline PEO/PVAc.Filled circle (X )and ®lled square (B )stand for samples for before and after CO 2treatments,respectively.smaller thickness,thus l 1 l c and l 2 l a :The inverse is true for f cs .0.5.f cs is related to the volume fraction of bulk crystallinity,f c ,byf c f s f cs 4where f s is the volume fraction of lamellar stacks in the sample.Since f s #1,Eq.(4)prescribes that f c cannot be higher than f cs .As a result,the assignment of l 1and l 2would be rather straightforward for f c .0.5,because l 1in this case must correspond to l a and l 2to l c .From the DSC measurements,f c of neat PEO and the blends containing 10and 20%PVAc lie above 0.5(Table 1),l 1and l 2were thus assigned to l a and l c ,respectively.l a and l c of these three samples before CO 2treatment are thus near 7and 32nm,respectively,from the corresponding one-dimensional correlation function pro®les (Fig.5).Although f c of the blend containing 30%PVAc is below 0.5,l 1can still be reasonably assigned to l a and l 2to l c for this blend because a big difference between l a and l c is present for neat PEO and the blends containing 10and 20%PVAc.This big difference between l a and l c is not likely to lead to an opposite assign-ment for l a and l c for the blend with f c below 0.5.Fig.6shows plots of l c and l a as a function of the weight fraction of PVAc (W PVAc ).Like the long period,l c and l a of samples before CO 2treatments are insigni®cantly varied with W PVAc .The thickness of crystal layer (l c )being weakY.-T.Shieh et al./Polymer 43(2002)3691±36983695Table 1The heats of fusion (D H ,J/g),melting temperatures (T m ,8C),volume frac-tional bulk crystallinities (f c ),and crystal layer thickness (l C ,nm)of PEO/PVAc blends for before and after CO 2treatments PEO/PVAcBefore CO 2treatment After CO 2treatmentD H 1T m1f C1l C1D H 2T m2f C2l C2100/0151.259.90.6831.8152.363.10.6943.590/10128.760.60.5831.6132.062.50.5943.580/20113.860.60.5131.8121.362.30.5443.770/3094.460.80.4231.884.461.50.3749.1Fig.5.One-dimensional correlation function of (a)neat PEO,(b)PEO/PVAc 90/10,(c)PEO/PVAc 80/20,(d)PEO/PVAc 70/30before CO 2treatments.Fig.4.Schematic plot of Strobl-Schneider's one-dimensional correlation function pro®le.Determinations of the lamellar layer thickness and the invariant assuming the corresponding two-phase model are demonstrated in the®gure.position variations of l c and l a of PEO/PVAc for (a)before,and (b)after CO 2treatments.functions of W PVAc can be associated with the assumption of corresponding two-phase model in deriving l c and l a from K z ;where the thickness of the crystal±amorphous inter-phase (l i )is `included'into the values of l c and l a .The interphase thickness can be estimated from the deviation from the self-correlation triangle near z 0(Figs.4,5and 7).The values of l i thus obtained are tabulated in Table 2.The interphase thickness for samples for both before and after CO 2treatment appears to be ,1nm,which is much smaller than l c or l a .These small l i values may be responsible for the observed weak functions of W PVAc for l c of samples before CO 2treatment.The thickness of amorphous layer (l a )being weak functions of W PVAc before CO 2treatment indi-cates that increasing PVAc does not swell the IL regions.This suggests that the increased PVAc content forms an extralamellar morphology.This result is not similar to what was obtained in Martuscelli and coworkers'work [11]having a ®nding of only IL morphology for the PEO/PVAc blends due to different sample preparations and/or molecular weight of PEO used between the previous work and this work.Samples used in the earlier work were subjected to heating and cooling treatments whereas samples studied in this work were prepared by solvent cast-ing without being subjected to heating and cooling treat-ments.Moreover,according to Runt and coworkers'work [18],factors that would reduce crystal growth rates could promote diluent segregation over greater length scales regardless of the diluent mobility at the crystallization temperature.PEO used in this work has a very high mole-cular weight that might have a reduced crystal growth rate.It is thus not unreasonable that the extralamellar morphol-ogy is obtained in this work.Since the purpose of this work is to investigate the effect of CO 2treatments on the phase structure of the blends,the disparity on the segregation morphology of the blends between the previous work and this work is not examined further here.Variation of l a and l c with PVAc composition for samples after CO 2treatment is also displayed in Fig.6.l a and l c of samples exhibit signi®cant increases upon CO 2treatment.After CO 2treatment,the amorphous and crystal layer thick-ness of neat PEO is raised by about 6and 12.6nm,respec-tively,which are much larger than the magnitude of l i .The swelling of l a is attributed to the incorporation of CO 2into the IL regions and thus the mass density is decreased,which is consistent with the enhancement of scattering intensity after CO 2treatment observed in Fig.2.The increased amor-phous layer thickness upon CO 2treatment exhibits an insig-ni®cant dependence on composition suggesting that the swelling of amorphous PEO in IL regions dominates the increase of the amorphous layer thickness.The signi®cant increase in l c of neat PEO upon CO 2treat-ment is associated with the occurrence of melting and recrystallization during CO 2treatment that leads to thicker PEO crystals via a depression of equilibrium melting temperature and/or an increase of crystal fold surface free energy.It has been reported that the crystal fold surface free energy can be increased by CO 2treatments for PET and sPS [47].According to the secondary nucleation theory,the initial crystal thickness is given by [48,49]l p g2s e T 0m 0f0m c ÀÁ1d l 5where s e is the fold surface free energy and D h 0f is the bulk enthalpy of melting per unit volume.At low to moderateY.-T.Shieh et al./Polymer 43(2002)3691±36983696Fig.7.One-dimensional correlation function of (a)neat PEO,(b)PEO/PVAc 90/10,(c)PEO/PVAc 80/20,(d)PEO/PVAc 70/30after CO 2treatments.Table 2Thickness of crystal-amorphous interphase (l i )estimated from K z of PEO/PVAc blends for before and after CO 2treatments PEO/PVAc Before CO 2treatment l i (nm)After CO 2treatment l i (nm)100/00.730.9890/100.730.9880/200.910.9870/300.910.98degree of supercooling,d l is small.Eq.(5)thus reduces to l p gù2s e T 0m D h 0fT 0m 2T c ÀÁ 6The ®nal crystal thickness,according to the notation of Hoffman and Weeks [48,49],is g times the initial thickness,i.e.l c g l p g7where g is the so-called lamellar thickness factor.Eq.(6)prescribes that the initial crystal thickness is inversely proportional to the degree of supercooling.Thus,a depres-sion of T 0m upon CO 2treatment that would lower the degree of supercooling at a given T C can lead to the formation of thicker crystals.As can be also known from Eq.(6),an increased crystal fold surface free energy during CO 2treat-ment can also give rise to the increase of l c .From Fig.6(b),l c increases with increasing W PVAc due to the depression of equilibrium melting temperature of PEO upon blending with PVAc [11].It is noted that the values of l a and l c determined from K z could face a large uncertainty because the broad lamellar size distribution could shift the position of the baseline (2A )[39].On the other hand,the electron density contrast,D h ,can be determined from K z with better con®dence in that D h is much less sensitive to the perturbation of baseline position for the samples with intermediate crystallinity 0:3,f cs ,0:7 :As shown in Fig.4,the invariant (Q )of the corresponding two-phase model for a sample (as in Figs.5and 7)is obtained by extrapolation from the self-correlation triangle to z 0[39].The invariant is related to the electron density contrast by [39]Q f s f cs 12f cs D h 28where f cs is the crystallinity within the lamellar stacks given byf csQ A 1Q9and f s is given by f c /f cs from Eq.(4).f c ,as tabulated in Table 1,is volume fraction of bulk crystallinity and is calcu-lated from weight fraction of crystallinity (v c )measured by DSC according to Eq.(10).f c v cr cv c r c 1 12v c r a v c v c 1r c r a 12v c 10 The weight fraction of crystallinity (v c )is determined by dividing the heat of fusion,D H ,in J/g of a sample by D H 0,which is 205J/g for perfectly crystalline PEO [40].r c (1.24g/cm 3)and r a (ca 1.12g/cm 3)are mass densities of crystal and amorphous component,respectively.D h can be calculated by Eq.(8)with the knowledge of Q ,f cs ,and f c .Table 3tabulated the D h values obtained from the measuredinvariant as a function of W PVAc for both before and after CO 2treatments.D h msd.1and D h msd.2are used to denote those measured D h values for before and after CO 2treatments,respectively.The plots of D h msd.1and D h msd.2as a function of W PVAc are shown in Fig.8.As can be seen in Table 3and Fig.8,the D h msd.1is insigni®cantly varied with W PVAc suggesting that the amount of incorporation of PVAc into IL regions does not increase with increasing W PVAc and thus the distance of segregation in PEO/PVAc blends involves the extralamellar paring between D h msd.1and D h msd.2for neat PEO,the CO 2treatment can cause an enhancement in elec-tron density contrast resulting from the swelling of IL regions by CO 2.This enhancement decreases with increas-ing W PVAc up to 0.2,indicating that below 0.2W PVAc the swelling of the IL regions by CO 2decreases with increasing W PVAc .The measured electron density contrast for the blend containing 30%PVAc is higher than that containing 20%PVAc,indicating that the expulsion of PVAc from IL regions has occurred upon CO 2treatment.These results are supported by the observation of the composition variation of appearance of ®lm samples after CO 2treatments.The presence of extralamellar morphology in the prepared blends can be demonstrated by the measured f s values of less than unity.Fig.9shows these measured f s values (f s1and f s2for before and after CO 2treatments,respectively)plotting as a function of W PVAc .As can be seen in Fig.9,for neat PEO,the f s1is less than unity,suggesting that the extralamellar segregation of PEO forms before blending with PVAc.The f s1decreases with increasing W PVAc ,suggesting that the segregation distance increases with increasing W PVAc .Upon CO 2treatment,theY.-T.Shieh et al./Polymer 43(2002)3691±36983697Table 3The measured D h ( h c 2h a )values of PEO/PVAc blends for before (D h msd.1)and after (D h msd.2)CO 2treatments PEO/PVAc D h msd.1D h msd.2100/00.0710.11290/100.0700.08680/200.0690.06970/300.0680.075parison between composition variation of the measured D h values for before (D h msd.1)and after (D h msd.2)CO 2treatments.。

江福林，卢云浩，何强. 茶多酚对植物乳杆菌、金黄色葡萄球菌和大肠杆菌生长的双向调节作用[J]. 食品工业科技，2023，44（22）：152−159. doi: 10.13386/j.issn1002-0306.2023040081JIANG Fulin, LU Yunhao, HE Qiang. Dual-directional Regulation of Tea Polyphenols on the Growth of Lactobacillus plantarum ,Staphylococcus aureus , and Escherichia coli [J]. Science and Technology of Food Industry, 2023, 44(22): 152−159. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2023040081· 生物工程 ·茶多酚对植物乳杆菌、金黄色葡萄球菌和大肠杆菌生长的双向调节作用江福林1，卢云浩2，何　强1,*（1.四川大学轻工科学与工程学院，四川成都 610065；2.成都大学食品与生物工程学院，四川成都 610106）摘　要：增强益生菌产品中益生菌的活力，同时抑制食源性致病菌及腐败菌的生长能够提升产品品质稳定性。

在单培养及共培养条件下，采用传统计数法和高通量测序比较研究了不同浓度的茶多酚对益生菌植物乳杆菌、致病菌金黄色葡萄球菌和大肠杆菌生长的影响。

单培养结果显示，随着茶多酚浓度增加，植物乳杆菌活菌数先增加后降低，在浓度为2.0 mg/mL 时活菌数最多，而两株致病菌的存活率不断降低，其中金黄色葡萄球菌更为明显。

在共培养体系中（金黄色葡萄球菌/大肠杆菌-植物乳杆菌），随着培养时间延长，植物乳杆菌的生物量不断增加，而致病菌数量和培养基pH 不断降低。

The 3rd ACF International Conference-ACF/VCA 2008 A.32COMBINED EFFECT OF SHRINKAGE REDUCING AND EXPANSIVE AGENTS ON AUTOGENOUS DEFORMATIONS OF HIGH-PERFORMANCE CONCRETEM.S. Meddah1-Postdoctoral Researcher; M. Szuki2- Consulting Engineer; R. Sato1- Professor1 2Dept. of Social and Environmental Eng, Graduate School of Engineering, Hiroshima University, Japan P.S.Mitsubishi Construction Co.,Ltd.ABSTRACT:Nowadays, high-performance concrete (HPC) has become widely used throughout the world in different construction filed. However, this type of concrete with low water-binder ratio (w/b) and ultrafine cementitious materials is known by high sensitivity to early-age cracking which is strongly related to a large amount of autogenous shrinkage. This paper investigates the reducing effect of autogenous shrinkage provided by the incorporation of a combination of shrinkage reducing agent (SRA) and expansive additive (EXA). The early-age development of both autogenous shrinkage and the induced stress of silica fume HPC mixtures made with three different w/b and using a combination of (SRA + EXA) were examined. The results have shown that for the control mixes, up to 90% of the ultimate autogenous shrinkage strains was exhibited during the first 24 hours. However, adding a combination of (SRA + EXA) results in a significant reduce of both autogenous shrinkage and the induced stresses. Furthermore, the use of such a combination has resulted in a very low shrinkage even non shrink HPC with a gradually internal stress development compared to the reference concrete.KEYWORDS:autogenous deformations, internal capillary stress, shrinkage reducing agent, expansive additive, anti-shrinkage agents, silica fume.1. INTRODUCTION High-performance concretes made with low w/b and ultrafine cementitious materials are known by high magnitude of autogenous shrinkage especially, at early-age. Autogenous shrinkage is considered as the main mechanism induced internal capillary tension that might result in earlyage cracking which is still the major problem relating to the use of HPC in reinforced concrete structure. Over the last decades, several techniques have been suggested to reduce autogenous shrinkage and consequently, the internal capillary stress that might increase the high sensitivity to early-age cracking. High belite or low heat Portland cement [1,2], super-absorbent polymer particles inclusions [3] as well as expansive additives (EXA) based on calcium sulfoaluminate or free lime [1,2] and shrinkage reducing admixtures [2,4,5] have been successfully and extensively used in inhibiting shrinkage. Even recently the internal water curing provided by the incorporation of pre-saturated lightweight aggregate (LWA) has revealed a high efficiency for autogenous shrinkage reducing and consequently, the induced capillary stresses [6,7,8,9], still the antishrinkage agents widely used to mitigate both autogenous and drying shrinkage of concrete.339The 3rd ACF International Conference-ACF/VCA 2008 The magnitude of autogenous shrinkage and consequently, the capillary tension within the solid hydrating cement paste corresponds to the surface tension induced by the formation of the menisci at the interfaces between the water-filled and empty pores. Therefore, reducing such type of shrinkage required reduces of surface tension into capillary pores. It is well known that SRA is designated to reduce the surface tension of water into pore solution of cement paste, whereas EXA are assigned to increase the volume of concrete by the transformation of a mixture of monosulfo-aluminate (C4A3 S ), lime (C) and anhydrite (C S ) into ettringite (C3A. 3C S H32); or the transformation of lime into calcium hydroxide (CH) [10]. Since the internal stresses in the pore solution are directly proportional to its surface tension, shrinkage reducing agent (SRA) which lowers this surface tension could also be used to mitigate autogenous shrinkage and early-age cracking in low w/b concretes. Therefore, the main functions of anti-shrinkage admixtures is to reduce capillary tension in pore solution that develops within concrete as it dries by both internal water consumption or due to external evaporation. The results of Hori et al. [1] indicate that the use of EXA reduces autogenous shrinkage, while calcium sulfoaluminate with high amount of free lime is more efficient than conventional calcium sulfoaluminate. Meanwhile, several authors have reported that the use of combination of SRA and EXA is more advantageous and reliable in shrinkage reducing than the mono-incorporation of either SRA or EXA separately [11] as well as using ternary system blended with low-heat cement and (SRA + EXA) [12]. Furthermore, results have shown that neither expansive agent nor SRA when used separately can definitely avoid the risk of cracking induced by shrinkage [10]. However, the use of combination of SRA and CaO-based expansive agent enable a synergistic effect in terms of more efficiency regarding the reduction of shrinkage. The objective of the present study is to elucidate the synergistic effect of such a combination (SRA + EXA) on both autogenous strains and stresses development for silica fume HPC. 2. EXPERIMENTAL INVESTIGATION 2.1. Materials and mixes composition A binary binder premixed low heat high belite cement (LHSF) containing 10% of SF as partial replacement of high belite cement was used for both reference and anti-shrinkage concrete mixtures. Crushed diabase with a maximum nominal size of 15 mm and crushed sandstone with a maximum size of 5 mm were used as coarse and fine aggregate, respectively, in saturated surface-dry conditions (SSD). Two types of anti-shrinkage agents were used to minimize the amount of autogenous shrinkage. Expansive additive (EXA) was used in combination with shrinkage reducing agent (SRA) based on lower-alcohol alkyleneoxide adduct having a specific gravity of 1.0. The content of EXA added was considered as part of the total content of cement, whereas, the amount of SRA incorporated was considered as part of the mixing water content. Therefore, for the treated concretes, the w/b is equivalent to (W+SRA)/(LHSF+EXA). To obtain the targeted slump flow, a Polycarboxylate superplasticizer (SP) having a specific gravity of 1.05 was used in all concrete mixtures. The mix proportions of the SF-HPC mixtures investigated in this study is presented in Table 1. Three different low w/b of 0.15, 0.23 and 0.30 have been adopted in order to perform the present study under somewhat severe conditions. The concrete was prepared in a laboratory pan mixer having as maximum capacity of 0.50 m3. The cement, SF and EXA, and fine aggregate were mixed first, followed by the addition of water and superplasticizer, and SRA in case. After the cement paste was reached the adequate consistent, coarse aggregate was lastly added and mixed together. Immediately after the end of the mixing 340The 3rd ACF International Conference-ACF/VCA 2008 sequence, slump follow, air content and temperature of concrete were determined. For the same type of concrete, all specimens were prepared from the same concrete batch and covered with plastic sheet. All the concrete specimens (prisms and cylinders) were sealed with aluminum waterproofing tape immediately after demoulding at 1 day in order to prevent any moisture loss during the whole testing period. Concrete mixtures were properly labeled using the notations indicated in this section. For concrete mixtures without anti-shrinkage agents, the alphabetical part designated the type of cement followed by number indicated the w/b of concrete. As all the concrete mixtures containing anti-shrinkage agents were made with the same binder type (LHSF) and the same content of SRA, and for simplification, they were designated using only the last part which indicated the content of EXA for expansive agent and R for the shrinkage reducing agent followed by the number indicated the w/b of the mix. Table 1- Mix proportions and fresh properties of the HPC mixtures investigatedConstituents kg/m3 LHSF EXA Water Gravel Sand SP SRA Slump flow, mm Air, % Mix designationLHSF-15 LHSF-23 LHSF-30 EX15-15 EX20-15 EX25-15 EX20-23 EX20-301033 155 944 445 25.8 600 1.8674 155 944 741 8.76 575 1.5517 155 944 875 4.65 190 1.81018 15 149 944 445 25.8 6 530 1.61013 20 149 944 445 23.3 6 685 1.91008 25 149 944 445 25.8 6 595 1.3654 20 149 944 741 8.76 6 580 1.0497 20 149 944 875 4.97 6 175 1.82.2. Testing methodology HPC mixtures investigated in the current study were subjected to two types of tests: mechanical tests, and strains and stresses development. Throughout the whole measurement period, the specimens were kept sealed under the same conditions (20 ± 1 °C and 60 ± 2 % of RH). In this study, measurement of both autogenous deformations and stresses were performed on two specimens and the mean value was reported. In the other hand, and for each concrete type, three cylinder specimens measuring 100 × 200 mm and 150 × 200 mm were used for compressive and splitting tensile strengths testing respectively, at the age of 1, 3 and 7 days of sealed curing according to JSI standard test. 2.2.1. Strains measurement The measurements of autogenous strains was performed on 100 × 100 × 400 mm specimens using a strain transducer of 100 mm gauge length embedded horizontally in the centre of the prism. Its low elastic modulus 400 kgf/cm2 allows measurement of strains that may occur during the very earliest stages of hydration reaction process. In addition to the strains measurements, this type of gauge is able to measure also temperature variation during cement hydration reaction. Prisms were recorded to a data logger system which is connected to a computer-controlled to collect data. Measurement starts immediately after concrete placement in the moulds and readings were taken every 10 min for 7 days. 2.2.2. Stresses measurement The proposed testing procedure used for stress measurements induced by shrinkage development was designed to offer partial restraint to the concrete specimen in order to simulate restrained 341The 3rd ACF International Conference-ACF/VCA 2008 conditions similar to those might found in real reinforced concrete structures. The loading system uses a preset degree of restraint by transferring the axial force to the concrete specimen through continuous embedded reinforcing bars. A specimen size of 100 × 100 ×1400 mm with reinforcing bar (D16) embedded in the centre of the concrete specimen was used for stress measurement. The axial force was measured with TML strain gauge placed longitudinally at the centre of the reinforcing bar. On each specimen, the concrete temperature variation was measured at the centre of the prism using embedded thermocouples (TC). The restrained stress development in concrete at the centre of the concrete specimen due to the restraint of reinforcement was determined using the equation (1). This equation is derived from the equilibrium of the force among concrete and reinforcement as well as Navier’s assumption, in which the stress is positive in tension and negative in compression. P σc = − s and Ps = As E s ε s (1) Ac where, Ps = the axial force in reinforcement, Es = Young’s modulus of reinforcement, = = stress on measurement strains in reinforcement, As = cross-section area of reinforcement, the extreme bottom fiber, = cross-section area of concrete. 3. RESULTS AND ANALYSIS 3.1. Mechanical properties In RC structure element, tensile and compressive strengths are the two major mechanical properties required for structural design purpose. The inclusion of anti-shrinkage agents in concrete mixtures may have an affect on both the compressive and tensile strengths development over time. Obviously, both the highest compressive and tensile strengths were achieved by the mix made with the lower w/b (LHSF-15) and the lowest strengths were obtained by the mix LHSF-30. Figs.1 and 2 provide the average value of the compressive and splitting tensile strength results up to 7 days for both the references and the treated concrete mixtures investigated. It can be observed that for the three w/b mixtures investigated herein, both early-age and 7 day-strength have shown a slight decrease of the compressive and tensile strengths with the incorporation of a combination of SRA and EXA at different proportions compared to the control mixes. In fact, as it can be seen in Fig. 1, the inclusion of EXA and SRA has rather a controversial effect. In one hand, for the three w/b mixtures, the inclusion of (EXA + SRA) results in a slight decrease of the compressive strength compared with the reference mix, and in another hand, for the same mixture with a w/b of 0.15, higher the content of EXA, lower the decrease of the compressive strength induced. It can be expected that the high content of EXA result in an important increase of the volume of concrete via the secondary ettringite formed, this could fulfill the empty space and coarser capillary pores which leads to a denser and strengthens cement paste. However, the small drop of the concrete strength may due to the microcraking that appear in the contact surface between the hardening cement paste and the secondary ettringite formed by the transformation of monosulfo-aluminate into ettringite as described above. Meanwhile, it should be noted as pointed out, that the SRA acts as a surface tension reducing within the pore solution which, basically, cannot significantly affect the strength of concrete. Therefore, such a decrease/increase of concrete’s strength is mainly related to the effect of EXA and the transformation process of monosulfo-aluminate into ettringite.342The 3rd ACF International Conference-ACF/VCA 2008120EX15- R- 15 EX20- R- 15 EX20- R- 23 EX20- R- 30LHSF- 15 LHSF- 23 LHSF- 30 EX- 25Splitting tensile strength (MPa)LHSF-15 EX20-23 LHSF-23 6 5 4 3 2 1 0 0 1 2 3 4 Time (days)EX15-15 EX20-30 LHSF-30Compressive strength (MPa)9060300 0 1 2 3 4 5 6 7567Time (days)Fig.1- Compressive strength developmentFig.2- Splitting tensile strength development3.2. Autogenous deformations development Autogenous strains of the HPC mixtures with and without anti-shrinkage agents were continuously measured on sealed specimens and the results obtained are plotted in Figs. 3 to 6. It can be seen that the w/b of concrete and the anti-shrinkage agents substantially affect both the ultimate magnitude and the development of autogenous strains. Results have shown that for the control mixtures without anti-shrinkage agents, decreasing the w/b of concrete leads to an increase of the magnitude of autogenous shrinkage. Lower the w/b is, greater the magnitude of autogenous shrinkage will be. In fact, lowering the w/b of concrete by 0.15 results in a significant increase in the autogenous shrinkage magnitude as shown in Fig. 3. The ultimate amount of autogenous shrinkage for the 0.15 concrete is estimated as the double of that of 0.30 concrete. As expected, the autogenous deformation behavior of concrete mixtures containing antishrinkage agents was clearly different than that of the control mixtures. For the same w/b of 0.15 and with the same content of SRA, increasing the content of EXA leads to a slight decrease of the magnitude of autogenous shrinkage as illustrated in Fig. 4. Obviously, the mix design and especially, the w/b of concrete is the major factor affecting autogenous strains development. In fact, while the 0.30 concrete has exhibited relatively an important expansion of around 80 µε, the 0.23 concrete has shown an initial shrinkage up to 12 hours which turned into an important expansion until 1 day. Beyond 1 day, the volumetric change behavior of both 0.30 and 0.23 concretes tends to stabilize and no significant deformations were recorded (Fig. 5). In addition, concrete mixtures with the same content of EXA (20 kg/m3) and made using different w/b have exhibited different volumetric contractions behavior as shown in Fig. 6. A quite similar expansion followed by stabilization after a short and pronounced shrinkage period was also recorded with the 0.15 concrete containing the same dosage of EXA+SRA as it can be seen in Fig.4 and 6. In fact, during the first hours, the hydration reaction results in a formation of hydrate products and pore network. SRA acts as a surface tension reducing within the pore solution however, EXA starts to react once the initial monosulfo-aluminate formed. The transformation of monosulfo-aluminate into ettringite leads to an increase of the volume of concrete which explain the expansion observed for the mixtures containing EXA. Meanwhile, the results have shown that while the combination of (SRA + EXA) could significantly reduce the magnitude of autogenous shrinkage, the completely elimination of such 343The 3rd ACF International Conference-ACF/VCA 2008 type of shrinkage is mainly related to the w/b of concrete. This combination was very efficient with 0.30 concrete and more or less with the 0.23 concrete; however even a significant reduces was observed with a very low w/b of 0.15, still less effectiveness was noted.100 LHSF100 Time (days) w/b = 0.15Autogenous shrinkage (µ ε)0 0 -100 -200 -300 -400 -500 1 2Autogenous shrinkage (µ ε)Time (days)3 4 5 6 70 0 -100 -200 -300 -400 LHSF -500 EX25-R EX20-R EX15-R 1 2 3 4 5 6 70.30 0.23 200 µε 0.15Fig. 3- Effect of w/b on autogenous shrinkage development of the control mixes100 Expansio n EX20-R-30Fig. 4- Effect of EXA content on autogenous shrinkage development for the 0.15 concrete0 200 1 2 3 4 5 6 7Autogenous strains (µ ε)50 0 -50 -100 -150 -200 -250 -300ShrinkageExpansio nAutogenous strains (µ ε)Time (days)0 1 2 3 4 5 6 7 EX20-R-23Time (days)EX20-R-30100 0 -100 -200 -300 -400ShrinkageEX20-R-23LHSF-30 LHSF-23EX20-R-15Fig. 5- Comparison of autogenous strains development for treated and non-treated concreteFig. 6- Effect of w/b on autogenous shrinkage development of treated concrete3.3. Internal stress development As it is well recognized, internal stress is the results of self-desiccation phenomena induced during cement hydration reaction progress. The total magnitude and the development of internal tensile stress are intimately related to the autogenous strains evolution. Figs. 7 and 8 present the induced stress development for the concrete mixtures investigated measured under sealed conditions during the first 7 days. The internal stress intensity exhibited by the various concrete mixtures investigated has shown to be strongly related to the w/b of concrete. While the inclusion of EXA and SRA has greatly contributed to reduce the internal stress level by approximately 0.68 MPa for the two treated concretes (EX15-R-15 and EX15-R-15) compared to the control mixture, still this type of concrete with very low w/b of 0.15 exhibits a high internal stress especially, at very early-age. It should be noted that for the 0.15 concrete, except a slight difference in the very early-age induced stress (until 1 day), no a significant difference has been observed when the content of EXA was increased from 15 to 20 kg/m3 as it can be seen in Fig. 7. Moreover, the 0.30 and 0.23 concretes have shown a relatively lower tensile stress of 0.23 and 0.31 MPa, 344The 3rd ACF International Conference-ACF/VCA 2008 respectively compared to the 0.15 concrete. However, adding the same content of EXA (20 kg/m3) and SRA (6 kg/m3) has completely eliminate the tensile stress for both concrete types and has induced a compression stresses. This compressive stress in the concrete specimen appears as a tensile stress in the reinforcement bar which is the result of the restrained expansion produced by the transformation of monosulfo-aluminate into ettringite as illustrated in Fig. 8.1.50.4TensionLHSF-23 LHSF-30Induced stress (MPa)Induced stress (MPa)1.2 0.9 0.6 0.3 0.0 -0.3 0EX15- R- 15 EX20- R- 15 LHSF- 15 1 2 3 4 5 6 7Time (days)Fig. 7- Internal stress development of 0.15 concrete mixtures with and without treatment.4. CONCLUSIONS Based on the experimental results of the present study, the following conclusions can be listed: 1. The inclusion of a combination of (SRA and EXA) has induced a slight decrease of both the compressive and tensile strengths of HPC. 2. Significant reduction of autogenous shrinkage and the induced stress of up to 50% was obtained using a combination of SRA and EXA for 0.15 concrete, while increasing the w/b of concrete up to 0.23 and 0.30 with the use of the same combination of (SRA+EXA) results in a drastically reduce even a completely elimination of both autogenous shrinkage and the internal stress induced. 3. The reduction of shrinkage amount and stress level seems to be pronounced with concrete having a w/b higher than 0.23. More than 80% of the ultimate magnitude of both autogenous shrinkage and stresses has been developed during the first 24 hours and no a significant increase was observed beyond this age. This may clearly illustrates the high sensitivity of HPC to earl-age cracking induced by autogenous shrinkage and the importance of a proper curing during this critical initial hydration phase. 4. The present study has resulted in a HPC with a very low shrinkage (EX20-R-23), even non shrink HPC (EX20-R-30), resulting in low crack sensitivity at early-ages and a durable HPC. 5. It can be confirmed that the combination of (SRA + EXA) with an appropriate content is very efficient to mitigate autogenous shrinkage strains and the stresses induced for HPC with w/b over than 0.23. 6. Finally, the results obtained have proven that the use of a hybrid system (SRA + EXA) can substantially improve serviceability, aesthetics and mainly durability of concrete structure by assisting in the reduction of early-age shrinkage and the induced tensile stress. 345aPM 86.0noisneT0.20.0EX20-R-23 EX20-R-30 Compression 0 1 2- 0.2- 0.4Time (days)34567Fig. 8 Effect of w/b on the internal stress development of treated and non-treated concrete.The 3rd ACF International Conference-ACF/VCA 2008 ACKNOWLEDGEMENTS Part of the research reported in this paper is supported by the Japan Society for the Promotion of Science (JSPS). The first author is gratefully acknowledges this financial support.REFERENCES 1. Hori, A. Marioka., M. Sakai, E., and Daimon, M. (1999), Influence of Expansive Additives on Autogenous Shrinkage. in Autogenous Shrinkage of Concrete, Edited by TAZAWA., E, E & FN Spon, London, pp. 93-104. 2. Ito, H. Maruyama, I. Tanimura, M., and Sato, R. (2004), Early Age Deformation and Resultant Induced Stress in Expensive High Strength Concrete. Journal of Advanced Concrete Technology, V. 2 (2), pp. 155-174. 3. Jensen, O.M., and Hansen, P.F. (2001), Water-Entrained Cement-Based Materials: I. Principle and Theoretical Background. Cement and Concrete Research, V. 31, N° 4, pp. 647-654. 4. JCI Committee Report. (1998), Technical committee on Autogenous Shrinkage of Concrete. Proceeding of International Workshop on Autogenous Shrinkage of Concrete. Hiroshima: Japan Concrete Institute, pp. 5-64. 5. Tazawa, E.I., and Miyazawa, S. (1997), Influence of Constituent and Composition on Autogenous Shrinkage of Cementitous Materials. Magazine of Concrete Research, V. 49, N° 178, pp. 15-22. 6. Philleo, R.E. (1991), Concrete Science and Reality. in Materials Science of Concrete II, J. Skalny, and S. Mindess, eds., American Ceramic Society, Westerville, OH, pp. 1-8. 7. Weber, S., and Reinhardt, H.W. (1997), A New Generation of High Performance Concrete: Concrete with Autogenous Curing. Advanced Cement Based Materials, V. 6, N° 2, pp. 59– 68. 8. Suzuki M., Meddah, M.S., and Sato, R., (2008), Use of Waste Porous Ceramic Aggregate for Internal Curing of High-Performance Concrete. Submitted to Cement & Concrete Research. 9. Meddah, M.S., and Sato, R., (2008), Early-Age Behavior of Low-Autogenous Shrinkage High-Performance Concrete. Submitted to ACI Materials Journal. 10. Collipardi, M. Borsoi, A. Collipardi, S. Ogoumah Olagot, J.J., and Troli, R. (2005), Effects of shrinkage Reducing Admixture in Shrinkage Compensating Concrete under non-wet Curing conditions. Cement and Concrete Research, V. 27, N° 6, pp. 704-708. 11. Tanimura, M. Hiramatsu, Y. Hyodo, H., and Sato, R. (2002), Flexural Performance of RC Memebers made of low Shrinkage High Performance Concrete. 6th International Symposium on Utilization of High Strength/High Performance Concrete, V. 2, Leipzig, Germany, pp. 1437-1452. 12. Sato, R., Tanaka, S., Hayakawa, T., and Tanimura, M. (1999), Experimental Studies on Reduction of Autogenous Shrinkage and its Induced Stress in High-Strength Concrete. in Autogenous Shrinkage of Concrete, Edited by Tazawa, E., E & FN Spon, London, pp. 163-171.346。

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