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协同系统发生的研究方法王智【摘要】协同系统发生研究生态上相关群体的系统发生间的关系,其研究方法主要分为两类:基于事件法和整体拟合法.基于事件法包括布鲁克斯简约分析、组分分析、协调树分析等,此类方法考虑进化情境,逻辑性强,但分析结果过多,较难选择;整体拟合法考虑了系统发生的误差,提供较好的关系一致性,但缺乏联系进化情境.本文详细比较了两类方法下各种分析软件的优劣,提出了整合两类方法的可能性,以便更好地理解协同系统发生.【期刊名称】《生物信息学》【年(卷),期】2014(012)001【总页数】5页(P33-37)【关键词】协同系统发生;基于事件法;整体拟合法;布鲁克斯简约分析【作者】王智【作者单位】陕西学前师范学院生物科学与技术系,陕西西安710100【正文语种】中文【中图分类】Q71 协同系统发生的概念协同系统发生(Cophylogeny，orparallel cladogenesis or co-cladogenesis)是研究生态上相关群体(如类群、地理区域，基因等)系统发生间的关系，在此，“主”(如有机体、寄生物的宿主或一个地区)系统发生是独立的，而“辅”(如基因、寄生物或有机体)系统发生在某种程度依赖于“主”系统发生［1］。
两个物种的协同进化是协同系统发生研究的主要领域之一。
使用协同进化这个术语时要区别协同趋异(Codivergence)和协同成种(Cospeciation)。
协同进化(Coevolution)指的是两个物种内或相互作用的种群内彼此进化变化的一般过程。
协同趋异指平行分支的进化过程(当一个物种分支为两个或多个物种时)或者说一个生物体实体的成种导致与此相关的其它生物体实体的成种［2］。
协同趋异与协同成种常常交替使用，一些学者认为协同趋异是相关类群分成截然不同的群体的过程，注重过程;而协同成种指的是它们已经独立进化为不同的物种，注重结果［3］。
协同趋异或协同成种可以说是协同进化的一部分。
第42卷第1期中国高原医学与生物学杂志Vol. 42No. 1 2021 年 C H IN E S E HIGH A LT IT U D E M E D IC IN E A N D B IO L O G Y2021多房棘球蚴影响PPARp、7表达并调控巨噬细胞极化％胡旺1•，张占红U2,冯浩杰h2,崔钰1'杜秋沛U2,于文昊]，樊海宁(1.青海大学附属医院肝胆胰外科，青海西宁810001;2.青海省包虫病研究重点实验室，青海西宁810001)摘要日的本研究旨在探讨多房棘球场影响过氧化物酶体增殖激活受体(3和7( Peroxisome proliferation-activated 表达并调控巨嗔细胞极化的状态。
方法在体外将RAW264. 7巨噬细胞与原头蚴共培养，用qR T-P C R和Western b o h法检测PPARp、7在 RA W264.7中的表达水平；用qR T-PC R法检测M l和M2相关标记物表达水平来研究PPAKp、7 对巨噬细胞极化的影响。
另外，再通过收集25例多房棘球蚴患者手术切除样本，用免疫荧光法检测M1/M2巨噬细胞在正常肝组织和边缘带的面密度值，以及PPAR(3、7在M1/M2巨噬细胞中表达的阳性强度，来进一步验证体外实验结果。
结果在巨噬细胞与原头蚴共培养中，巨噬细胞极化标记物的M l型巨噬细胞标记物呈先上升后下降的趋势，而M2型巨噬细胞标记物整体呈上升的趋势。
PPAR|3、7的表达分别与M1/M2标记物的变化趋势一致。
同时，临床样本分析显示PPAR(3、7 的表达分别与M l和M2极化的趋势一致。
结论提示PPARp、？在多房棘球蚴病中分别参与M1、M2极化调控。
关键词：过氧化物酶体增殖激活受体；巨噬细胞;极化；多房棘球蚴病中图分类号：R535 文献标识码：AD0I： 10. 13452/j. cnki. jqmc. 2021.01. 001Echinococcus Multilocularis Affects PPARp,7Expression and Regulates Macrophage Polarization*HU Wang1'2*,ZHANG Zhanhong1'2 ,FENG Haojie1'2,CUI Yu1'2,DU Qiupei''2,YU Wenhao',FAN Haining1'2*(1. Department of Hepatobiliary and Pancreatic Surgery, Qinghai University Affiliated Hospital,Xining,Qinghai Province,810001 ,China；2. Qinghai Provincial Key Laboratory of Hydatid Disease Research ,Xining,Qinghai Province 810001 China)Abstract Objective The purpose of this study was to investigate the expression of Peroxisome proliferation-activated receptorsp&"y( PPARp ,^) to regulate macrophage polarization in alveolar echinococcosis ( AE ) .Methods The expression levels of PPARp，7in RAW264. 7 macrophages were detected by qRT-PCR and Western Bolt in vitro co-culture. The expression levels of Ml and M2-related markers were detected by qRT-PCR to investigate the effects of PPARp, -y on the polarization of macrophages. In addition, 25 patients with multilocular echinococcsis※：国家重点研发计划“精准医学研究”重点专项（2017YFC0909900)，青海省包虫病研究重点实验室项目（2020-Z J-Y01)，青海大学附属 医齒中W年科娇S金项目（201^-Q Y Y-8) ;#:通讯作者，教授，博士生辱ffi，E-mail:fanhaining@ medmail. com. cn胡旺（1992~ )，男，汉族，湖南籍，在读研究生were collected and the surface density of M1/M2 macrophages in normal liver tissues and liver lesion ranging was detected by immunofluorescence as well as the positive intensity of PPARp,"y expression in M1/M2 macrophages to further verify the results of the in vitro experiment. Results Ml macrophage polarization markers increased first and then decreased, while M2 markers showed an increasing trend in the co-culture. Simultaneously, the expressions of PPARp，7were consistent with the variation of Ml and M2 markers. Meanwhile,the analysis of the clinical samples revealed that the expression of PPARp，7were in agreement with the trend of Ml and M2 polarization respectively. Conclusions It is showed that PPARp,7may regulate Ml and M2 polarization respectively in AE.Keywords ： PPAR(3, y； Macrophage ； Polarization ； Alveolar echinococcosisIntroductionAlveolar echinococcosis( AE) is a zoonotic parasitic disease caused by the infection of echinococcus mul- tilocularis larvae in the middle taenia stage1. Transmitted by ingesting the parasite eggs,AE is excreted in the feces of the definitive host and then infected by oral ingestion of parasite eggs in ungulates and humans (intermediate hosts) ~.It is mainly prevalent in animal husbandry areas and is globally distributed, principally in Asia, Africa, South America, the Middle East, Central Europe, North America, Alaska, Hokkaido, Japan and western China 34. In 98% of the cases, the liver and lungs are the main infected organs presenting with tumor - like invasive and metastatic growth. Approximately 90% of the patients die within 10 to 15 years without treatment^5. It is estimated that there are more than 18,000 new AE cases worldwide each year with China accounting for 91 %[6•Owing to the risk of the disease, AE has been listed by the World Health Organization ( WHO) as one of the 20 neglected tropical diseases. AE is a food borne parasite that ranks third in the global impact among the 24 parasitic diseases^4.Macrophages are highly plastic which can respond to the microenvironmental signals by changing their phenotypes to obtain corresponding functions. There are two major subpopulations of macrophages with different functions, including classically activated macrophage (Ml )and alternatively activated macrophage ( M2) 17. Ml and M2 phenotypes are the two extremes of macrophage polarization which jointly regulate the homeostasis of its internal environment. The two phenotypes are reversible and interconvertible. Ml has proinflammato- ry, antigen -presenting, host immune clearance of pathogens and tumor cells,while M2 mainly inhibits in- 2flammation and promotes tumor growth，invasion and metastasis18,9.Peroxisome proliferation -activated receptors (PPARs) are a family of adopted orphan nuclear receptors involved in lipid metabolism and inflammation, including PPARa, PPAR(3/8, and PPAR^. Each of species has distinct ligands, target genes and biological functions 10. PPARs are involved in the metabolism and homeostasis of fat and carbonate in the organism as well as cell proliferation and differentiation, vascular biology, inflammation and carcinoma 13. PPARs are mainly expressed in the kidney, liver, small intestine, heart and other tissues to activate fatty acid catabolism14. PPARs play an important role in regulating immune response which affect mononuclear cells, macrophages, neutrophils, peripheral blood lymphocytes, dendritic cells,T cells,NK cells and eosinophils 15,16. Besides,it is found in these studies that PPAR (3,7are also involved in the process of macrophage polarization in metabolic and infectious diseases 7. Since the effect of PPAR p, 7on macrophage polarization in AE has not been reported yet, the purpose of this study was to analyze the effect of PPAR on macrophage polarization in AE.1. Material and Methods1.1 Collection of echinococcus multilocularis proto-scolex( PSC)PSC was extracted from the infected gerbils in the laboratory, while PSC in gerbils was inoculated from the naturally infected wild voles at Guoluo of Qinghai province in China. The gerbils were sacrificed by cervical dislocation. Then, they were placed in the cell plates on the benchtop to open the abdominal cavity and the lesions were separates and removed. Next, the lesionswere cut into a paste with scissors,and the funnel was placed at the mouth of a 50 mL centrifuge tube for filtration with an 80 - molybdenum cell screen. PSC was allowed to sediment for 15 mins in the 50 mL centrifuge tube. After PSC settled at the bottom, the supernatant was sucked out with a straw and normal saline was added to the centrifuge tube. The above was repeated 3-5 times. Finally，a little PSC was stained with Trypan blue to observe the activity and count of the nodes. PSC was incubated in RPMI 1640 ( Gibco) culture medium containing 100 U/mL penicillin，100 jxg/mL streptomycin ,20% heat -inactivated fetal bovine serum (FBS) ,0. 45% yeast extract and 0. 4% glucose in a 5% C02 atmosphere at 37 for 10 h. Then,PSC was used in the subsequent experiment.1.2 Co-culture experiment of RAW264. 7 macrophages with PSCRAW264. 7 macrophages ( Procell Life Science & Technology Co,. Ltd ) were cultured in Dulbecco's modified eagle media( DMEM) solution containing 10% FBS, 100 U/mL penicillin and 100 |xg/mL streptomycin in a 5% C02atmosphere at 37 T i. All the experimental interventions were carried out on the third pas- sage of cells. The cell suspension was dropped onto the cell count plate and counted under the light microscope. The cells were placed in the plates of DMEM solution containing 10% FBS. The non - adherent cells were removed after incubation for 4 h, and the adherent RAW264. 7 macrophages were added into 1mL DMEM containing 1000 viable PSC for co-culture. The cells were collected for total RNA and protein extraction on days 1,3,5 and 7 after co-culture.1.3 Total RNA isolation and real-tim e polymerase chain reaction(PCR)Total RNA was extracted using RNA Simple Total RNA Kit(TIAN GEN®),and the purity of RNA was de- termined by calculating the absorbance ratio at 260 nm and 280 nm. It was showed that the ratio of 1. 8〜2. 0 was suitable for cDNA synthesis. cDNA was synthesized by reverse transcription of 1jxg of total RNA using the PrimeScript RT Reagent kit ( TaKaRa ). For real - time polymerase chain reaction(PCR) ,80 ng cDNA was added in a 15 |xL reaction system containing each primer and TB Green PreMix (TaKaRa ). The reaction conditions were 95 °C for 30 s, followed by 40 cycles of 95 X l for 5 s,60 T! for 30 s and the melting curve analysis at 63 Tl 〜95 Tl. 18S rRNA was used as a housekeeping gene.Relative mRNA amounts were quantified by the 2 A A<丨method. The mice gene primers ( provided by Sangon Biotech)were as follows (Table 1).i 1Mice primersT N F-aG M-C S F M-C S FI F N-7RI Arg-1T G F-pP P A R pP P A R7 18S r R N A C A G C C G A T G G G T T G T A C C T TT C G T C T C T A A C G A G T T C T C C T T C AC C C A A C G A G T C A G C A A C T C AT G T A G C C T C A C C G C C T A T C A CA C A C G G C A G T G G C T T T A A C C TC A A C A A T T C C T G G C G T T A C C T TG G A C C A G A A C A C A C G C T T C C T TG T A C T G T C G G T T T C A G A A G T G C CG T A A C C C G T T G A A C C C C A T TG T G T G G G T G A G G A G C A C G T AC C C G T A G A C C C T G C T C G A AC A G C A C A A T G C C C C A A G A GT T G T T G T T T G G G A G A G A T T C C AG G T A G T C A G T C C C T G G C T T A T G GG A C G T C A A A A G A C A G C C A C T C AC C G A C A T T C C A T G T T G A G G C T GA T C T C C G C C A A C A G C T T C T C C TC C A T C C A A T C G G T A G T A G C GPrimer Forward( 5,-3,)Reverse( 5,-3,)1.4 Western blot analysisThe levels of PPAR(3N7and ACTIN protein expression were measured by the Western blot analysis. The whole protein extracted from RAW264. 7 macrophage was separated by 10% SDS polyacrylamide gel electrophoresis ( SDS - PAGE ) . The protein samples were transferred to polyvinylidene difluoride membranes and incubated with PPARp ( 1：1000, Abeam) ,PPAR 7(1： 800, Cell Signaling Technology), and ACTIN ( 1：8000, protein tech® ) antibody over-3night at 4 . Next,the membranes were washed thrice using a mixture of tris-buffered saline and polysorbate 20and incubated with horseradish peroxidase-conjugated secondary antibody( 1：10000, Abeam) at room temperature for 1h before signal detection by the chemiluminescent substrate.1.5 Liver histology and immunofluorescence analysisFor confirming the normal liver tissue and liver lesions ranging, the liver tissue samples were fixed to 10% formalin, paraffin-embedded , hematoxylin and eo- sin. Immunofluorescence was performed to detect the area density of M1/M2 polarization and the positive intensity of PPA Rp,^ in macrophages about the normal liver and liver lesions ranging which were obtained from clinically resected specimens of patients ( Table2 ) with hepatic alveolar echinococcosis ( HAE ). The nucleus turned blue by labeling with DAPI. In immunofluorescence mono - staining, Ml marker CD86 ( Servicebio ) and M2 marker CD206( Servicebio) turned red by labeling with CY3 ( Servicebio).In immunofluorescence double staining, M1/M2 markers were all green - labeled with FITC ( Servicebio) ,and P P A R p^were red-labeled with CY3. Expression quantification of markers was performed with the Image-Pro plus 6. 0 open-sources developed at Media Cybernetics in USA.Table 2 General clinical data of the patients (n = 25)Basic information Cases Percentage Sex Male1352. 0%Female1248. 0% Ag e彡401664. 0%<40936. 0% Infection Stage Middle stage1040. 0%Late stage1560. 0%1.6 Statistical analysis interferon -"y receptor 1 (INF-"y R1) peaked on the thirdData were represented as mean ± standard error day after treatment, showing a trend of rising first andof the mean( SEM ) using Student^s t-test. For experiments of more than three groups, statistical analyses were performed with analysis of variance followed by the post hoc Tukey pairwise comparisons. It is considered to be dramatically changed when the P —val- ue<5%. The specified p-values were showed in the figures as follow: * P<0.05;**P<0.01;** * P<0. 005；* * * * P<0. 001.2. Results2. 1RAW264. 7 macrophage mainly polarized toward Ml in the early stage and M2in the late stage after in vitro PSC stimulationTo further understanding the polarization of RAW264. 7 macrophages during co-culture with PSC, the polarization trend of macrophages was observed by detecting M l/M l polarization markers through real -then decreasing ( Figure 1A 〜B ). As shown in Figure 1C，the mRNA level of granular macrophage - colony stimulating factor( GM-CSF) increased significantly on the third day until it reached a peak on clay 5 and then began to decline. Figure ID demonstrates that the changes in Ml markers (T N F-a, I NF-^y Kl,and GM- CSF )increased first and then decreased after RAW264. 7 co-cultured with PSC. Compared with the controls,the increased mHNA levels of Arg-1 transforming growth factor-p(TGF-(3) and GM-CSF were increasing significantly on day 3 after treatment and then gradually reached peaking on day 7 ( Figure 2A 〜C). It was showed in Figure 2D that the change of M2 markers illustrated an overall upward trend after RAW264. 7 co-cultured with PSC. The above results suggested that macrophage co-culture with PSC is mainly polarizedtime PCR. In comparison with the control group, the toward Ml in the early-stage and M2 in the late stage. mRNA levels of tumor necrosis factor-a( TN F-a ) andIF N - y R1★ ★★HControl *Co-Cultrue(Day) D1D3D 5D73~I■TNF- a-IFN- y RT N F -a GM-i(Day) D1 D3 D5 D7A 〜C :T h e m R N A expression of M l markers genes( T N F 一〇d ，I F N - 7 R 1，and G M -C S F ) in R A W 264. 7 macrophage are measured by q R T -P C R. D ：T he overall variation of m R N A expression of T N F -a ,I F N 一y R1 and G M -C S F genes at different time points. * P<0. 05； * * P<0. 01 ； * * *P <0. 005； * * * *P <0. 001 vs. control.Figure 1 the mRNA expressions and trend of Ml markers detected by qRT-PCRBTGF-/3Arg-1Control Co-CultrueControl Co-Cultrue(Day)D5 D7-CSFControl Co-CultrueArg-1TGF-P M-CSFA ~C ：T he m R N A expression of M 2 markers genes( Arg-1 ,T G F -p ,a n d M -C S F )i n R A W 264. 7 macrophage are measured by q R T -P C R. I)：The overall variation trend of m R N A expression of Arg-1 ,T G F -p ,a n d M -C S F ' genes at different time points. * P<0. 05； * * P <0.01; * * *P <0.005; * * * *P <0. 001 vs. control.Figure 2 the mRNA expressions and trend of M2 markers detected by qRT-PCR/§a7§Q C E e /v /;e /eQ CA VN t rE e >!i B I 9a:a -LL z lc<z cr E <v >c s o a :LL s o l s o5Control D1Control D3Control D5Control D7P P A R p P P A R7 ACTIN 53k D a 53k D a 43k D aA〜B:m R N A expression of P P A R p，7 genes in R A W264. 7 macrophages i s measured by q R T-P C R. C:Overall variation of m R N A expression of P P A R p，7 genes at different time points. D: Level of P P A R p，7 protein expression in R A W264.7 macrophages measured by Western blot analysis. A C T I N is used as a loading control. * P<0.05； * * P<0. 01 ； * * * ^<0. 005； * * * * P<〇.001 vs. control.Figure 3 the expressions of PPARp,^ detected by qRT-PCR and WB in RAW264. 7 macrophages of each group2. 3 The macrophages in liver lesions ranging were mainly M2 polarization in patients with HAEMacrophage polarization was verified with clinical samples to determine its tendency in HAE. The progression of HAE is slow with no obvious clinical symp- 6toms. The herdsmen in western China are primarily in the middle and late stages after being diagnosed with the disease. Therefore, all the clinical surgical samples were collected from patients with advanced stage.First, hematoxylin and eosin ( HE ) staining were2. 2PPA Rp,^ play an important role in the polarization of macrophages co-cultured with PSCFor a better understanding of the effect of PPARp，7on macrophage polarization in AE, the expression of PPA Rp,^ macrophages after co-culture with PSC was detected by real-time PCR and Western blot analysis. Figure 3A reveals that the expression of PPARp mRNA reached its peak on day 3 after RAW264. 7 co 一cultured with PSC and then began to decline. However, Figure 3B showed that PPAR7mRNA expression of macrophages was significantly lower than the control at one day of co-culture with PSC and significantly increased after five days of co - culture. The overall change in the trend of PPAR(3, y in RAW264. 7 co - cultured with PSC was that PPARp first increased and then decreased, while PPAR7continued to increase ( Figure 3C). Moreover, the protein expression level of PPARp in the macrophages c〇-cul- tured with PSC also showed a trend of increase, followed by the decrease. The level of the protein was the highest on day 3. The expression level of PPAR7 showed an overall upward trend with the highest expression on day 7 ( Figure 3D). Based on the results mentioned above, it was found that the expression of PPARp in RAW264. 7 co-cultured with PSC was consistent with the changing of Ml polarization marker, and that of PPAR7was consistent with the changing of M2 polarization marker. Therefore, it was considered that PPARp mainly regulated the polarization of Ml macrophages in the early stage of infection in AE disease, while PPAR7mainly regulated the polarization of M2 macrophages in the late stage,cP P A R P ControlCo-Cultrue P P A R y ControlCo-Cultrue+P P A Rpperformed on all samples before immunofluorescence detection for confirming the normal liver tissue and liver lesions ranging. The liver lesions ranging was defined as the peripheral inflammatory infiltration zone that a- way from the central necrotic tissue 0. 5 〜1 cm ( Figure 4A). As shown in Figure 4B, there are prominent hepatic lobules in the normal liver tissues with extensive infiltration of granulocytes and lymphocytes in liver lesions ranging. Immunofluorescence staining was performed on the markers of M1/M2 in the normal liverand liver lesions ranging( Figure 5A 〜B ). The results showed that M2 ( CD206 ) polarization macrophages were significantly increased in the liver lesions ranging, while Ml ( CD 86) polarization macrophages were significantly decreased compared with the normal liver (Figure 5C 〜D ). These data demonstrate that macrophage polarization in the middle and late stages of HAE was mainly M2 polarization in the liver lesions ranging, which also verified the results of the in vitro experiment of macrophage polarization toward M2 in the late stage.Ax 10°Liver lesion rangingx400x200 x400Hematoxylin and eosin ( H E ) staining was performed on all clinical samples before immunofluorescence detection to confirm the normal liver tissue and liver lesion rangingFigure 4 HE staining of clinical samples7A~B:Immuno f l u o r e s c e n c e staining of M l(C D86)and M2(C D206)markers in the normal liver and liver lesion ranging. C〜I): Areal density values of M1(C D86)/M2(C D206)markers in the normal liver and liver lesion ranging are analyzed. Data represented m e a n土standard error of the m e a n(S E M)，n =25 clinical samples, * P<0. 05 vs. controlFigure 5 Immunofluorescence staining of clinical samples with M1/M2 makers2.4 PPA Rp,^ are involved in the regulation of macrophage polarization in HAEIn the in vitro experiments, PPARp, 7were considered to regulate the polarization of macrophages M1 and M2 respectively. For further verification of this result, the expression of PPA Rp,^ in macrophages was detected by immunofluorescence double staining. As shown in Figure 6A 〜B，the M1，M2 macrophages and PPARp in the nomial liver and liver lesions ranging were simultaneously stained by immunofluorescence. By analyzing the average intensity of PPARp t'xpression in Ml and M2 macrophages, it was found that the PPARp expression in I V11macrophages was significantly decreased compared with that in normal liver,and the expression of PPAF^p in M2 macrophages was not signifi- cantly different from that in normal liver( Figure 6C 〜I)). Meanwhile, immunofluorescence staining and analysis of PPAR7in Ml and M2 macrophages showed that the expression of PPAR7in M2was significantly increased compared with the control. However, theex-0 001...1 ----,~I — 0.00-1-1 ~I I~A 〜B:Immunofluorescence staining of P P A R p in M l (Cl)86) and M 2(C D 206) macrophages in the normal liver and liver lesionranging. C 〜D : Average intensity analysis of P P A R (3 expression in M 1 ( C D 86)and M 2( C D 206) macrophages. Data represented m e a n ±standard error of the m e a n (S F.M ) ,n = 25 clinical samples, * P <0. 05 vs. controlFigure 6 Double immunofluorescence staining of clinical samples with PPARB and M1/M2 makerspression of PPAR 7 in Ml was not significantly different compared with that in the normal liver ( Figure 7A 〜 D). It is showed in the experimental detection of clinical samples that the expression trends of PPARp, 7 inNormal liverMl and M2 macrophages were consistent with those in vitro experiments. Therefore, it can be concluded that PPAR(3 mainly regulates Ml polarization, while PPAR0/ mainly regulates M2 polarization in HAE.Liver lesion rangingNormal liver Liver lesion rangingCDThe expression of P PA Rpin M1(CD86) macrophagesThe expression of PPAR p in M2(CD206) macrophages〇 Normal liver〇 Normal liverA ,864 20.0.0.0 0.0.0.0.^/s c ec / e o )5e >.<o «a a :<ca .Q .86 4 20 0.00 0.0.0.0. ^_-m c s £&s a >a9A〜B: Immunofluorescence staining of P P A R*y in M l (C D86)and M2(C D206)macrophages in the normal liver and liver lesion ranging. C〜D: Average intensity analysis of P P A R^y expression in M l(C D86)and M2(C D206)macrophages. Data represented m e a n ± standard error of the m e a n(S E M),n=25 clinical samples, * 尸<0. 05 vs. controlFigure 7 Double immunofluorescence staining of clinical samples with PPAR7 and M1/M2 makers3. DiscussionsIt is observed in this study that the macrophage polarization could be induced during the co-culture of PSC and macrophages, and the increased expression of PPARp,^y in macrophages was related to the polarization of Ml and Ml macrophages respectively. The data also confirmed that the infection of larval echinococcus multilocularis leads to the polarization of macrophages. This co-culture model has its limitations as it is not a 10primary infection owing to the ingestion of oncospheres, nor is it a non-natural host. Most importantly, this study suggests that the regulation of macrophage polarization may l)e a potential target for AE therapy. The findings provide new clues to the basic pathogenesis and progression of AE so as to greatly advance our understanding of AE. Thus, it is significantly advancing our understanding of AE.AE is an alarming clinical zoonotic parasiticdisease with the chronic progressive liver damage caused by the continuous proliferation of multilocular echinococcosis in the larval stage as its main characteris- tic….Additionally，immune tolerance and/or immune downregulation is a remarkable feature that is increasingly observed as AE disease progresses to the chronic stage of infection 18. Studies have revealed that the pathological changes of AE are related to the infiltration of macrophages at specific stages of various functional types[丨9].Macrophages are a critical component of the innate immune system and a key regulator of normal homeostasis and patholog) -0-1They not only mediate the innate and specific immune responses of the body but also participate in the process of immune tolerance 22 . Macrophages have different functions owing to their different subtypes. Ml macrophages mainly have the function of proinflammatory, antigen presentation, host immune clearance of pathogens and tumor cells,while M2 macrophages have the function of anti-inflammatory, promoting wound healing, fibrosis, tissue repair, promoting tumor growth and infiltration. Through the co-culture of macrophages with PSC,it is observed that the macrophages were primarily Ml polarization before day 3,followed by M2 polarization. Therefore, it is speculated that the Ml polarization macrophages in the early stage of larval multilocular echinococcus infection were mainly responsible for the clearance of pathogens in the body. Other studies have indicated that the macrophages from mice infected with larval multilocular echinococcosis exhibited a lower ability to present an antigen to specific T lymphocytes compared with that in mice without infection 3.It was found in this study that PSC could induce the polarization of macrophages. However, macrophages are mainly polarized toward M2 with the progression of the disease, which is more conducive to the growth and infiltration of the pathogen, leading to the aggravation of the disease. Thus, macrophage polarization, mainly toward M2, may be an important mechanism for immune tolerance to pathogens in the late stage of HAE.Currently, it is critical to explore the molecular mechanism of macrophage polarization in AE disease. Several other studies revealed that PPARs play an important role in the regulation of macrophage polarization in the signal pathway. The expression of PPAR(3/8 in macrophages can be increased by activation of STAT6, thereby inhibiting the activation of JNK to regulate the transformation between Ml and M2[24. Additionally, STAT6/PPAR7pathway regulates the generation of many M2-type markers 25. Also, some cytokines ( such as T N F-a, IL-12, IL-23 , IL-27 , and IFN-7) activate PPARs,which will inhibit the production of proinflammatory cytokines. They are and are essential for the formation ,activation, and maintenance of M2 macrophage ~6. It is hypothesized that PPAR(3,7might mediate the regulation of Ml and M2 macrophages polari- zation in AE respectively. It is observed that the expression trend of PPARp,^ in Ml and M2 was consistent with the expression trend of M1/M2 polarization markers in both the in vitro and clinical sample experiments.The survival mechanism of echinococcus multiloc- ularis larvae is to protect itself from the body’s immune response. The pathology of AE is characterized by intense infiltration of the immune cells 27. After natural infection in the intermediate host, the immune system should encounter different stages of parasite development 17. When the parasite is not effectively suppressed by the surrounding protective immune response ,it eventually becomes a fully mature metaces- tode that will continue to grow until the host dies 28. This study suggests that PPAR(3,7are involved in the regulation of macrophage polarization in HAE. Therefore, it is considered that the direction of M1/M2 polarization could be regulated by regulating the signaling pathways of PPAR(3 and PPAR7in macrophage polarization. In the complete process of disease infection, more induction of macrophage polarization toward Ml and reduction of M2 polarization may slow the progression of the disease.In conclusion, we have demonstrated the role of PPAR(3,7on macrophage polarization in AE. The results of this study are important implications for further understanding of the AE pathogenesis, providing a potential target for AE treatment.Disclosure of conflict of interestThe authors declare no competing conflicts of interest.。
biological invasionˌ[ˌbaɪəˈlɑdʒɪkəl ɪnˈveʒən] 生物入侵Global Aquaculture Education全球水产养殖教育aquaculture水产养殖Cage culture[kedʒˈkʌltʃɚ]网箱养鱼Lobster[ˈlɑbstɚ] 龙虾Life History生活史Blue Crab [blu kræb] 三疣梭子蟹；蓝蟹；青蟹channel catfish斑点叉尾鮰biodiversity[ˌbaɪodɪˈvɚrsɪti]生物多样shrimp [ʃrɪmp] 虾；小虾shellfish贝类algae[ˈældʒi] 藻类aquatic plant[əˈkwætɪk plænt] 水生植物freshwater淡水pond池塘pearl珍珠mortality[mɔrˈtælɪti] 死亡率reproduction繁殖mollusc[ˈmɑləsk] 软体动物crustacean [krʌˈsteʃən] 两栖动物clam[klæm] 蛤oyster[ˈɔɪstɚ] 牡蛎abalone[ˌæbəˈloni] 鲍鱼scallop[ˈskɑləp] 扇贝amphibian[æmˈfɪbiən]两栖动物crayfish [ˈkreˌfɪʃ] 小龙虾reptile [ˈrɛptɪl, -ˌtaɪl] 爬行动物breeding繁殖；饲养seafood海鲜catfish鲶鱼trout [traʊt] 鳟鱼，鲑鱼dissolved oxygen溶解氧Spawn[spɔn]产卵Mate配对Sponge [spʌndʒ] 海绵molt[molt]脱皮predator['prɛdətɚ] 捕食者Distribution分布Mature成熟的embryo['ɛmbrɪo]胚胎Animal protein['protin]动物蛋白Fishmeal鱼粉Capture fisherie捕捞渔业Fisheries resources渔业资源starfish海星packets of sperm[spɝm] 数包精子planktonic[,plæŋk'tɔnik]浮游生物Hatchling['hætʃlɪŋ] 人工孵化King Crab, Red King Crab皇帝蟹Fishery渔业Enhancement[in'hænsmənt]增加Symposium[sɪm'pozɪəm]讨论会Workshop车间forum['fɔrəm]论坛small scale/large scale experiment小范围/大型实验broodstock cultivation 亲鱼培育Air stone气泡石Flow through溢流道Larval/larve['lɑrvəl]幼虫Artemia卤虫Larval diet幼虫饮食Hatchery['hætʃəri]孵化器larve/fry/fingerling/ Juvenile['dʒʊvənaɪl]幼虫（体）diatom['daɪətəm]硅藻nutrition enrichment[njuˈtrɪʃn]营养强化survial生存dry weight干重duration[du'reʃən] of experiment实验持续时间Vibrio ['vɪbrɪ,o] bacteria 弧菌fatty acid /protein['protin]/amino acid[ə,mi:nəu 'æsid] 脂肪酸/蛋白质/氨基酸Pond culture池塘养殖Aquaculture modes水产养殖模式“Eight Words”Water,Seeds, Feeds, Density，Polyculture混养, Rotation[ro'teʃən] 轮流, Disease[dɪ'ziz]疾病Management，paddy ['pædɪ]cuture稻田养殖Silver carp 鲢鱼Bighead carp 鳙鱼Grass carp草鱼Black carp青鱼Common carp鲤鱼Crucian carp鲫鱼Blunt snout bream武昌鱼（团头鲂）Mud [mʌd]carp鲮鱼Mandarin['mændərɪn] fish鳜鱼Japanese eel日本鳗鲡River crab河蟹；大闸蟹Chinese mitten['mɪtn] crab中华绒蝥蟹Japanese prawn[prɔn]日本对虾Tilapia[tə'lɑpiə] 罗非鱼Rainbow trout[traʊt]虹鳟Largemouth bass['lɑ:dʒmauθbes]大嘴鲈鱼 Giant tiger prawn 草虾giant river prawn 罗氏沼虾 Penaeus monodon Giant tiger prawn 斑节对虾Kelp海带White leg shrimp白对虾Litopenaeus vannamei凡纳滨对虾Litopenaeus vannamei Boone 对虾Big yellow croaker['krokɚ]大黄鱼Perch[pɝtʃ] 鲈鱼turbot['tɝbət]大比目鱼Intensive [ɪn'tɛnsɪv] culture集约化养殖Extensive [ɪk'stɛnsɪv] culture粗养formulate['fɔrmjə'let] feed配合饲料water quality ['kwɑləti] management水质管理optimal['ɑptəml] temperature最适温度Sexual maturity['sɛʃʊəl mə'tʃʊrəti]性成熟Food Habits食性Spawning time['spɔ:niŋ] 产卵期powdered feed粉状饲料pelleted ['pɛlɪtɪd]feed颗粒饲料Stocking density放养密度Raft筏Loach[lotʃ]泥鳅Tuna['tunə]金枪鱼Seed collector集卵器Shell[ʃɛl]贝壳Water temperature['tɛmprətʃɚ]水温Yellow tail[tel]黄尾袋鼠Experimental station试验站Suitable feed合适的饲料Man-made shelter['ʃɛltɚ]人工海礁In diameter[daɪ'æmɪtɚ]/width/depth直径/宽度/深度Salmon['sæmən]大马哈鱼Conserve/conservation保存/保护Young fish幼鱼Artificial fertilize[,ɑrtɪ'fɪʃl 'fɝtəlaɪz]人工受精Life cycle生命周期species物种Basic research基础研究Hatch/hatching孵化Migratory ['maɪɡrətɔri]fish 洄游鱼类Coastal ['kostl] waters沿海水域Large scale大规模的Penaeus monodon斑节对虾Giant tiger prawn草虾grass prawn草虾Mangrove['mæŋɡrov]红树林omnivorous [ɑm'nɪvərəs]杂食的 herbivory [hə:'bivəri]草食性carnivorous[kɑrˈnɪvərəs]肉食性的Fertilization[,fɝtlə'zeʃən]受精nauplius['nɔpliəs]无节幼体Protozoea[ˌproʊtə'zəʊə]蚤状幼体mysis['maisis]糠虾；糠虾幼体；糠虾期metamorphose[,mɛtə'mɔrfoz] 变态salinity[sə'lɪnəti]盐度milkfish虱目鱼Eel鳗鱼Estuary['ɛstʃʊ'ɛri]河口Anguilla anguilla[æŋ'ɡwilə]欧洲鳗鲡anguilla japonica[dʒə'pɑnɪkə]日本鳗鲡Glass eel 玻璃鳗Yellow eel黄鳗silver eel银鳗Recirculating Aquaculture System再循环水产养殖系统recirculating/recirculation system再循环/再循环系统progeny['prɑdʒəni] 后代Secondary['sɛkəndɛri]次要的Grow-out养殖出来Fingerling['f ɪŋgɚ,lɪŋ]小鱼Selective [sɪ'lɛktɪv]harvest选择性收获Secondary species/Main species主要/次要物种的物种Organic fertilizer[ɔr'gænɪk 'fɝtəlaɪzɚ]有机肥料Marketable size市场规格Culture period培养期Fertility生育能力Water body水体Stocking size放养规格Murray cod['mʌri;]虫纹石斑鱼golden perch[pɝtʃ]黄金鲈silver perch银鲈offspring ['ɔfsprɪŋ]子代survival rate[ret]存活率scale规模handling处理capture捕获oxygenation[,ɑksədʒə'neʃən]氧化作用parasite['pærəsaɪt]寄生虫formalin['fɔrməlɪn] 福尔马林antibiotics[,æntɪbaɪ'ɑtɪks]抗生素methylene ['mɛθɪlɪn]blue美蓝malachite green['mæləkaɪt]孔雀石绿fungal['fʌŋɡl] 真菌heal治愈yolk sac[sæk]卵黄囊Mm(millimeter)毫米Cm(centimeter)厘米µm(micrometer)测微计Aquatic Diseases水生疾病Stress压力Chemical Stressor['strɛsɚ]化学压力源Biological stressor生物压力源Microorganism微生物Population[,pɑpju'leʃən] density种群密度Physical stressor物理压力Procedural stressor 程序上的压力Pathogen['pæθədʒən]病原体；病菌immunity[ɪ'mjʊnəti] 免疫力Mucus['mjukəs]粘液Inflammation['ɪnflə'meʃən]炎症Antibody['æntɪ'bɑdi]抗体sodium['sodɪəm] 钠potassium[pə'tæsɪəm]钾chloride['klɔraɪd]氯dehydration[,dihaɪ'dreʃən] 脱水Sanitation[,sænɪ'teʃən] 环境卫生Nitrogenous [naɪ'trɑdʒənəs]含氮的organic debris[də'bri] 有机残骸Disinfect['dɪsɪn'fɛkt]消毒Infectious 传染性Parasitic[,pærə'sɪtɪk]/parasite寄生/寄生虫Protozoa[,protə'zoə] 原生动物Proteins['protiɪn]蛋白质Lipids['lipidz]脂类Carbohydrate[,kɑrbo'haɪdret]碳水化合物Vitamins维生素Minerals['mɪnərəl]矿物质Attractants[ə'træktənt]引诱剂plant protein植物蛋白animal protein动物蛋白crude protein粗蛋白Essential[ɪ'sɛnʃl] amino[ə'mino] acids['æsɪd]必需氨基酸Methionine[mɛ'θaɪənin]蛋氨酸lysine['laɪsɪn] 赖氨酸Essential fatty acids必需脂肪酸chloroform['klɔrəfɔrm]/methanol['mɛθənɔl] 氯仿/甲醇high unsaturated[ʌn'sætʃə'retɪd] fatty acids (HUFA)高不饱和脂肪酸Energy代谢能Digestible[daɪ'dʒstəbl] Energy可消化能Feed Conversion[kən'vɝʒn] Ratio[reʃɪo](FCR)饲料转化率Polyculture of bighead carp in ponds and pensIn China, bighead carps are usually cultured as secondary species together with other carp species. The grow-out stocking density is 750-1500/ha of 13-15 cm fingerlings. If selective harvesting is to be practiced, a certain proportion of larger sized fish (up to 250 g) is also stocked. There is no special feeding/fertilization required for bighead when herbivorous and omnivorous fish are cultured as the main species. However,organic fertilizer is usually applied to raise natural food if bighead and silver carp are cultured as major species. The fish can reach marketable size (750-1500 g) within 8-10 months in China. The culture period may be much shorter in tropical and subtropical areas. The yield of bighead carp is usually 500-1000 kg/ha, which accounts for 10-15% of the total production.In Vietnam, bighead grow-out is conducted through polyculture with other species, such as grass carp, silver carp, rohu, mrigala, common carp and tilapia. Bighead carp is stocked as a minor species in the ponds, usually accounting for 3-5% of the total. However, bighead carp usually account for 5-7% of the total production. No special feeding for bighead carp is practised. The market size of bighead carp is 2.5-3 kg. Extensive culture in small lakes and reservoirsIn this system, bighead carp are usually stocked as the major species, with a stocking density of 150-750/ha, depending on the size and fertility of the water body. This level represents about 40-50% of the total number of fish stocked. The stocking size is usually 13-15 cm. A small percentage of large fingerlings (up to 250 g) is also stocked for selective harvesting to fully utilize the water and the available natural food. Neither feed nor fertilizer is used in this form of rearing. The production of bighead can reach 150-400 kg/ha, which accounts for 40-60% of total production.池塘和网拦鳙鱼的混养在中国，鳙鱼与其他鲤科鱼类通常作为次要种类。
malaria的英语作文Malaria, a life-threatening disease caused by parasites transmitted through the bites of infected mosquitoes, haslong been a scourge in many parts of the world, particularlyin sub-Saharan Africa, South Asia, and parts of South America. This essay aims to explore the nature of malaria, its impacton global health, and the ongoing efforts to combat this deadly disease.Understanding MalariaMalaria is a complex disease with several species of the Plasmodium parasite responsible for infecting humans. Themost severe form of the disease is caused by Plasmodium falciparum, which can lead to severe anemia, organ failure, and even death if not treated promptly. The transmission ofthe disease is highly dependent on the presence of the Anopheles mosquito, which thrives in warm, humid climates.The Global ImpactThe World Health Organization (WHO) estimates that there were 229 million cases of malaria worldwide in 2019, resulting in over 409,000 deaths. The majority of these fatalities were among African children under the age of five, highlightingthe devastating impact of malaria on vulnerable populations. Economically, malaria imposes a significant burden, not only through direct healthcare costs but also through lostproductivity and impeded socio-economic development.Strategies for Combating MalariaThe fight against malaria involves a multifaceted approach that includes prevention, treatment, and research into new solutions. Key strategies include:1. Vector Control: The use of insecticide-treated bed nets and indoor residual spraying to reduce the mosquito population and limit the transmission of the disease.2. Diagnosis and Treatment: Rapid diagnostic tests and effective treatment with artemisinin-based combination therapies (ACTs) are crucial to reducing the mortality rate from malaria.3. Vaccination: The development of a malaria vaccine has beena significant milestone. The RTS,S/AS01 (RTS,S) vaccine, also known as Mosquirix, is the first vaccine to demonstrate a protective effect against malaria in young children.4. Research and Development: Continued investment in research is essential for developing new drugs, diagnostics, and vaccines to combat drug-resistant strains of malaria.5. Community Education: Educating communities about the risks of malaria and how to prevent it is vital in reducing transmission rates.Challenges and the Road AheadDespite significant progress, challenges remain. Climate change, insecticide resistance, and funding constraints are just a few of the hurdles that the global health community must overcome. The COVID-19 pandemic has also disrupted malaria prevention and treatment services, leading to concerns about a potential resurgence in cases.ConclusionMalaria remains a significant threat to global health, but through concerted efforts and innovative strategies, the tide is slowly turning. The goal of a world free from malaria is ambitious but achievable. It will require sustained commitment, collaboration across borders, and a continued focus on research and community engagement. As we continue to battle this ancient foe, the lessons learned and the progress made in the fight against malaria will undoubtedly contribute to the broader fight for global health equity.。
关于疟疾的介绍英语作文Malaria, a disease caused by Plasmodium parasites transmitted through the bite of infected female Anopheles mosquitoes, remains a significant global health challenge. Here's an introduction to malaria:Introduction:Malaria, a mosquito-borne infectious disease, poses a significant threat to public health, particularly in tropical and subtropical regions. Despite substantial progress in controlling malaria over the years, it continues to be a major cause of morbidity and mortality worldwide.Cause:The causative agents of malaria are Plasmodium parasites, with five species known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae, andP. knowlesi. Among these, P. falciparum and P. vivax are the most common and virulent species.Transmission:Malaria is primarily transmitted through the bite of female Anopheles mosquitoes. When an infected mosquitobites a human host, it injects sporozoites, the infectious form of the parasite, into the bloodstream. These sporozoites then travel to the liver, where they multiply and mature into merozoites, leading to the onset of symptoms.Symptoms:The clinical manifestations of malaria vary depending on the species of Plasmodium involved and the individual's immunity. Common symptoms include fever, chills, headache, muscle aches, and fatigue. In severe cases, malaria can progress rapidly to complications such as cerebral malaria, severe anemia, respiratory distress, and organ failure, posing a grave threat to life.Diagnosis:Diagnosing malaria typically involves examining blood samples under a microscope to detect the presence of Plasmodium parasites. Rapid diagnostic tests (RDTs) arealso available, providing quick and accurate results, particularly in resource-limited settings where microscopy may not be readily accessible.Treatment:The treatment of malaria depends on factors such as the species of Plasmodium involved, the severity of the disease, and the individual's age and medical history. Artemisinin-based combination therapies (ACTs) are currently thefrontline treatment for uncomplicated P. falciparum malaria, while other antimalarial drugs such as chloroquine and primaquine are used for other species and in certainregions where drug resistance is not prevalent.Prevention:Preventing malaria relies on a multifaceted approach, including vector control measures such as insecticide-treated bed nets, indoor residual spraying, and environmental management to reduce mosquito breeding sites. Additionally, chemoprophylaxis with antimalarial drugs may be recommended for travelers visiting endemic areas, along with personal protective measures such as wearing long-sleeved clothing and using insect repellents.Challenges:Despite concerted efforts to control malaria, several challenges persist, including the emergence and spread of drug-resistant parasites, insecticide resistance in mosquitoes, limited access to healthcare services in remote areas, and inadequate funding for malaria control programs. Addressing these challenges requires sustained political commitment, innovative research, and collaboration among various stakeholders at the global, national, and local levels.Conclusion:In conclusion, malaria remains a significant global health burden, affecting millions of people worldwide and posing challenges to disease control efforts. While progress has been made in reducing malaria-related morbidity and mortality, concerted efforts are needed to achieve the goal of malaria elimination and eventual eradication. By investing in research, strengthening healthcare systems, and implementing comprehensive prevention and control strategies, we can mitigate the impact of malaria and improve the health and well-being of vulnerable populations.。
青蒿素的发现对人类社会的重大意义英语作文全文共3篇示例，供读者参考篇1The Discovery of Artemisinin: A Therapeutic Breakthrough Against MalariaMalaria has been one of the most devastating diseases to afflict humankind throughout history. This deadlymosquito-borne illness has claimed countless lives, impeded economic progress, and perpetuated cycles of poverty in many regions of the world. However, a groundbreaking discovery in the late 20th century offered a glimmer of hope in the seemingly endless battle against this formidable foe – the isolation of artemisinin, a potent antimalarial compound derived from the sweet wormwood plant (Artemisia annua).The journey toward this remarkable achievement began in the 1960s when the Vietnamese leader Ho Chi Minh urged scientists to find an effective cure for malaria, which was ravaging his nation's troops during the war. In response, a secret military project code-named "Project 523" was launched, mobilizing hundreds of researchers to scour traditional Chinesemedical texts and investigate thousands of potential antimalarial drug candidates from herbs and plants.After years of painstaking research, a breakthrough came in 1972 when researchers from the project, led by Tu Youyou, successfully extracted and purified artemisinin from the sweet wormwood plant. This compound exhibited remarkable efficacy against the malaria parasite, rapidly reducing parasite levels in the bloodstream and offering a much-needed alternative to the failing chloroquine and quinine treatments.The significance of this discovery cannot be overstated. Malaria, a disease caused by the Plasmodium parasite, had long been a scourge upon humanity, particularly in tropical and subtropical regions. According to the World Health Organization (WHO), malaria caused an estimated 627,000 deaths worldwide in 2020, with Africa bearing a disproportionate burden, accounting for over 90% of these fatalities.Prior to the discovery of artemisinin, the available antimalarial drugs were losing their potency due to the rapid emergence of drug-resistant strains of the Plasmodium parasite. Chloroquine, once hailed as a miracle cure, had become increasingly ineffective in many parts of the world, leaving healthcare professionals scrambling for alternative treatments.Artemisinin offered a much-needed solution to this growing crisis. Unlike many other antimalarial drugs, artemisinin and its derivatives exhibited a novel mechanism of action, rapidly reducing parasite levels in the bloodstream and preventing the transmission of the disease. Moreover, artemisinin-based combination therapies (ACTs), which combine artemisinin derivatives with other antimalarial drugs, have proven to be highly effective in combating drug-resistant strains of the parasite.The impact of artemisinin on global health has been profound. Since its introduction, ACTs have become the gold standard for treating uncomplicated malaria cases worldwide, saving millions of lives and significantly reducing the disease burden, particularly in sub-Saharan Africa. The WHO has consistently recommended the use of ACTs as the first-line treatment for malaria, recognizing their superior efficacy and ability to delay the emergence of drug resistance.Beyond its therapeutic applications, the discovery of artemisinin has also catalyzed scientific progress and fostered international collaboration. Extensive research has been conducted to optimize the production, formulation, and delivery of artemisinin-based drugs, leading to advancements in fieldssuch as synthetic biology, process chemistry, and drug delivery systems.Furthermore, the story of artemisinin's discovery has inspired researchers around the globe to explore traditional medicine systems for potential therapeutic leads. This has opened up new avenues for drug discovery and highlighted the importance of preserving and studying indigenous knowledge systems, which have often been overlooked or undervalued in modern scientific research.However, despite the remarkable achievements facilitated by artemisinin, the battle against malaria is far from over. Drug resistance remains a constant threat, with the first signs of partial resistance to artemisinin derivatives emerging in certain regions of Southeast Asia. Additionally, factors such as climate change, urbanization, and human migration patterns continue to influence the global malaria burden, necessitating sustained efforts in prevention, surveillance, and treatment strategies.Moreover, the availability and accessibility ofartemisinin-based therapies remain a challenge in many resource-limited settings, where malaria exacts its heaviest toll. Factors such as inadequate healthcare infrastructure, supplychain issues, and financial barriers often impede the widespread distribution and utilization of these life-saving treatments.Addressing these challenges will require a concerted global effort involving governments, healthcare organizations, research institutions, and the private sector. Continued investment in research and development is crucial to stay ahead of emerging drug resistance and to develop more affordable and accessible antimalarial therapies. Additionally, strengthening healthcare systems, improving disease surveillance, and implementing effective vector control measures are essential components of a comprehensive malaria elimination strategy.As we reflect on the impact of artemisinin, we are reminded of the power of scientific inquiry, perseverance, andcross-cultural collaboration in addressing humanity's greatest challenges. The discovery of this remarkable compound has not only saved millions of lives but has also ignited hope for a future where malaria is no longer a threat to global health and development.In conclusion, the isolation of artemisinin from the sweet wormwood plant stands as a testament to the transformative potential of scientific breakthroughs. Its discovery has forever changed the landscape of malaria treatment, offering a lifeline tocountless individuals and communities afflicted by this devastating disease. While challenges remain, the story of artemisinin serves as a beacon of hope, reminding us of the remarkable progress that can be achieved through unwavering commitment, international collaboration, and a deep respect for traditional knowledge systems.篇2The Discovery of Artemisinin: A Monumental Breakthrough for Global HealthAs students, many of us may take modern medicine for granted, never truly appreciating the remarkable scientific discoveries that have saved millions of lives worldwide. One such groundbreaking achievement is the isolation of artemisinin, a compound derived from sweet wormwood (Artemisia annua) that has proven to be a potent weapon against malaria – a deadly parasitic disease that has plagued humanity for centuries. The story behind artemisinin's discovery is a testament to human ingenuity, perseverance, and the relentless pursuit of knowledge for the betterment of society.Malaria, a mosquito-borne illness caused by the Plasmodium parasite, has been a scourge upon humankind since ancienttimes. Throughout history, this insidious disease has claimed countless lives, impeded economic development, and perpetuated cycles of poverty in endemic regions. Despite decades of research and numerous attempts to develop effective treatments, the battle against malaria remained an uphill struggle until a remarkable breakthrough occurred in the 1970s.It was during this time that a team of Chinese scientists, led by Tu Youyou, undertook a top-secret project to find a cure for malaria. Inspired by traditional Chinese herbal medicine practices, Tu and her colleagues meticulously screened thousands of ancient texts and folk remedies, seeking any potential leads. Their perseverance paid off when they stumbled upon a reference to the use of sweet wormwood (qinghao) for treating fever – a telltale symptom of malaria.Undeterred by initial setbacks and skepticism, Tu and her team persisted, refining their extraction methods and experimenting with various solvents. Finally, in 1972, they succeeded in isolating the active compound responsible for the plant's anti-malarial properties – a molecule they named "artemisinin" (qinghaosu).The significance of this discovery cannot be overstated. Artemisinin-based combination therapies (ACTs) quickly becamethe gold standard for treating malaria, offering a highly effective and well-tolerated treatment option. Unlike many conventional antimalarial drugs, artemisinin and its derivatives rapidly reduced the parasite load in the body, alleviating symptoms and preventing the progression of the disease to its most severe and life-threatening stages.The impact of artemisinin on global health has been profound. According to the World Health Organization (WHO), the widespread adoption of ACTs has played a pivotal role in reducing malaria mortality rates by over 60% since 2000. This remarkable achievement has saved millions of lives, predominantly in sub-Saharan Africa and other regions where malaria remains endemic.Moreover, the discovery of artemisinin has catalyzed a renewed interest in exploring traditional medicine practices and natural products as potential sources of new drug leads. This interdisciplinary approach, combining ancient knowledge with modern scientific techniques, has opened up new avenues for drug discovery and highlighted the invaluable contributions of diverse cultural traditions to the advancement of human health.Beyond its direct impact on malaria treatment, the story of artemisinin's discovery serves as an inspiration to scientists,researchers, and students alike. It exemplifies the power of perseverance, open-mindedness, and the willingness to explore unconventional paths in the pursuit of knowledge. Tu Youyou's unwavering determination, combined with her team's meticulous research and innovative thinking, serves as a shining example of how scientific breakthroughs can emerge from unexpected sources.Furthermore, the recognition of Tu Youyou's achievements through the Nobel Prize in Physiology or Medicine in 2015 has shed light on the significant contributions of women in science, particularly in developing nations. Her success has paved the way for greater representation and recognition of female scientists, inspiring generations of young women to pursue careers in scientific fields and make their mark on the world.As students, we can draw valuable lessons from the discovery of artemisinin. It teaches us the importance of perseverance, open-mindedness, and the willingness to explore unconventional paths in the pursuit of knowledge. It reminds us that scientific progress is often the result of collaborative efforts, drawing upon diverse perspectives and cultural traditions. And perhaps most importantly, it instills in us a sense of hope – a belief that even the most daunting challenges can be overcomethrough unwavering determination and the relentless pursuit of knowledge for the betterment of humanity.In conclusion, the discovery of artemisinin stands as a monumental triumph of human ingenuity and scientific endeavor. Its impact on global health has been nothing short of transformative, saving millions of lives and paving the way for further advancements in the fight against malaria. As students, we can draw inspiration from this remarkable story, recognizing the power of perseverance, open-mindedness, and the pursuit of knowledge to create a better world for all.篇3The Momentous Discovery of Artemisinin and Its Profound Impact on HumanityEver since the dawn of human civilization, diseases have posed a formidable challenge to our species' survival and progress. Throughout history, epidemics and pandemics have wreaked havoc, claiming countless lives and impeding societal development. However, in the annals of medical breakthroughs, few discoveries have been as pivotal as the isolation of artemisinin, a potent antimalarial compound derived from the sweet wormwood plant. This revolutionary finding has not onlypaved the way for more effective treatments against the deadly scourge of malaria but has also catalyzed broader advancements in global health and socioeconomic welfare.Malaria, a mosquito-borne parasitic disease, has been a relentless foe for humanity, particularly in tropical and subtropical regions. Its devastating impact has been felt across generations, with millions succumbing to its ravages annually. Children, in particular, have borne the brunt of this disease, as their underdeveloped immune systems render them especially vulnerable. Entire communities have been trapped in cycles of poverty and underdevelopment, their economic and social progress stunted by the constant threat of malaria.Against this grim backdrop, the discovery of artemisinin by Chinese scientist Tu Youyou in the 1970s marked a turning point in the fight against this ancient scourge. Through her unwavering dedication and innovative approach, which involved revisiting ancient Chinese medical texts, Tu Youyou and her team unlocked the potential of the sweet wormwood plant, Artemisia annua, as a potent antimalarial treatment.The impact of this discovery cannot be overstated. Artemisinin-based combination therapies (ACTs) have proven to be highly effective in treating malaria, even in regions where thedisease has developed resistance to other antimalarial drugs. By rapidly reducing the parasite load in the body, ACTs have saved millions of lives, particularly those of vulnerable children and pregnant women.Beyond its direct impact on malaria treatment, the discovery of artemisinin has had far-reaching implications for global health initiatives. It has reinvigorated the quest for novel therapeutic agents derived from natural sources, inspiring researchers worldwide to delve into the vast repository of traditional medicinal knowledge. The success of artemisinin has underscored the importance of preserving and studying indigenous practices, recognizing the invaluable wisdom embedded within diverse cultural traditions.Moreover, the adoption of ACTs as the front。
小学上册英语第四单元期中试卷考试时间：80分钟（总分:100）B卷考试人：_________题号一二三四五总分得分一、综合题(共计100题共100分)1. 填空题：I have a _____ (滑梯) in my backyard. I love to slide down it!我在后院有一个滑梯。
我喜欢从上面滑下来！2. 填空题：The lynx has tufted ________________ (耳朵).3. 选择题：What is the name of the region in space where most comets originate?A. Oort CloudB. Kuiper BeltC. Asteroid BeltD. Heliosphere4. 选择题：What is the name of the famous ship that carried the Pilgrims to America?A. MayflowerB. Santa MariaC. TitanicD. Pinta5. 填空题：My dad enjoys __________ (写作).6. 听力题：The flowers are ___ (growing) taller.7. 听力题：The chemical symbol for cobalt is _______.8. n rainforest is rich in ______ (生物多样性). 填空题：The AmerI can ______ (定期) reflect on my progress.10. 选择题：What is the capital of the Comoros?a. Moronib. Moutsamoudouc. Mitsamioulid. Domoni答案:a11. 填空题：I love _______ (参加)运动会.12. 选择题：What is the main purpose of a school?A. ShoppingB. LearningC. PlayingD. Eating13. 听力题：I like to ______ new games with my friends. (try)14. 选择题：What do you call a baby lion?A. CubB. KittenC. PupD. Calf15. 选择题：What is the capital of South Africa?a. Johannesburgb. Pretoriac. Cape Townd. Durban答案:b16. 填空题：The __________ (历史的传递) conveys lessons.17. 听力题：We need to ________ the house.The _______ of a wave can be calculated using its frequency.19. 填空题：在中国，古代的________ (ceremonies) 反映了人们的信仰与文化。
2020-2021学年郑州市第三十六中学高三英语模拟试卷及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AHottest Travel DestinationsSometimes figuring out the best place to go can be difficult. Here are some hottest travel destinations that offer some of the most beautiful, artistic, and fashionable places on the globe.Ibiza, SpainWhile Ibiza is knownas a party city, there is far more to do in this historic town than simply drink and dance under the stars. Built mainly in the second century, it’s a world heritage site with architecture dating back to as early as the 7th century. Don’t miss Charo Ruiz, Ibiza’s most famous fashion brand. Plus, the Ibiza Fashion Festival takes place every June.Tangier, MoroccoKnown as the “door to Africa”, Tangier has a rich and complex history dating back thirty centuries. It has all the beauty of the natural world. After spending a morning sunbathing by the Mediterranean Sea, get in some amazing shopping and discover great deals on everything. Before you head home, stop off in Marakesh to visit some of the top Moroccan designers.Havana, CubaStepping onto the streets of Havana feels like stepping back in time. For a day of sightseeing, check out the remaining architecture of Old Havana, which was built ten centuries ago. You can easily do it with one of the area’s many walking tours. Or visit the Museum of Rum for a taste of the island’s most popular wine. You might come across a clothing shop offering some classic finds!Melbourne AustraliaBuilt largely during the 1850s gold rush, Melbourne remains as alive as ever. Make sure to check out the hottest Australian brands. Moreover, visit the Block Arcade in Collins Street to see some of the 19th century architectural details the world has to offer. And, if you want to catch the largest consumer fashion festival in the world, grab tickets for the yearly Virgin Australia Melbourne Fashion Festival.1.What can visitors do in both Ibiza and Havana?A.Taste local wine.B.Visit modern Museums.C.Appreciate ancient buildings.D.Enjoy parties under the stars.2.To attend the globally largest consumer fashion festival, you have to go to ________.A.SpainB.MoroccoC.Havana.D.Australia3.Which of the following cities is the oldest?A.Ibiza.B.Tangier.C.Havana.D.Melbourne.BCuckoos don’t bother building their own nests—they just lay eggs that perfectly imitate those of other birds and take over their nests. But other birds are wishing up, evolving some seriously impressive tricks to spot the cuckoo eggs.Cuckoos are often know asparasites, meaning that they hide their eggs in the nest of other species. To avoid detection, the cuckoos have evolved so that eggs seem reproduction of those of their preferred targets. If the host bird doesn’t notice the strange egg in its nest, the little cuckoo will actually take the entire nest for itself after it comes out, taking the other eggs on its back and dropping them out of the nest.To avoid this unpleasant fate for their young, the other birds have evolved a few smart ways to spot the fakes, which we’re only now beginning to fully understand. One of the most amazing finds is that birds have an extra colour-sensitive cell in their eyes, which makes them far more sensitive to ultraviolet wavelengths and allows them to see a far greater range of colours than humans can. This allows cautious birds to detect a fake egg which might be exactly the same to our eyes.Fascinatingly, we’re actually able to observe different bird species at very different points in their evolutionary war with the cuckoos. For instance, some cuckoos lay their eggs in the nests of the redstarts. The blue eggs these cuckoos lay are practically alike to those of the redstarts, and yet they are still sometimes rejected. Compare that with cuckoos who target dunnocks. While those birds lay perfectly blue eggs, their cuckoo invaders just lay white eggs with brown irregular shaped spots. And yet dunnocks barely ever seem to notice the obvious trick.Biologists suspect these more easily fooled species like the dunnocks are on the same evolutionary path as the redstarts, but they have a long way to go until they evolve the same levels of suspicion. What’s remarkable is that the dunnocks fakes are so bad and the redstart ones so good, and yet cuckoos are still more successful with the former than the latter.It speaks to just how thoroughly a species’ behavior can be changed by the pressures of natural selection, or it might just be a bit of strategic cooperation on the part of the dunnocks. Biologists have suggested that these birds are willing to tolerate a parasite every so often because they don’t want to risk accidentally getting rid of one of their own eggs.4. This passage can be most likely found in a ________.A. science surveyB. nature magazineC. zoo advertisementD. travel journal5. What does the underlined word “parasite” in paragraph 2 most probably refer to?A. Animals that work together to raise young.B Small harmful animals such as worms or mice.C. Animals that can adapt to changing environments.D. Animals which live on or inside other host animals.6. Which of the following is TRUE about the dunnock according to the passage?A. It is colour-blind and therefore cannot identify foreign eggs in the nest.B. It can easily remove cuckoo eggs from the nest because fakes are so bad.C. It is a host bird that is more likely to raise a cuckoo chick than the redstart.D. It is unable to evolve and hence accepts cuckoo eggs that appear in the nest.7. Which of the following can be inferred from the passage?A. Dunnocks may eventually learn to recognise foreign eggs.B. Redstarts seem to be less suspicious compared to dunnocks.C. Cuckoo birds are good at taking responsibility for their own young.D. It is very easy for cuckoos to imitate the colouring of the dunnock’s egg.COne billion people in the world are short of water. How can this problem be solved. Some suggestions have been to desalinate ocean water or to build enormous water pipelines from areas where water is abundant. (Suggestions such as these prove extremely expensive when they are actually used.) One possibility that scientists are considering is pulling icebergs from either the North Pole or the South Pole to parts of the world with a water shortage. Although many questions must be answered before such a project could be tried, moving icebergs seems a reasonable possibility in the future.Engineers, mathematicians, and glaciologists from a dozen countries have been considering the iceberg as afuture source of water. Saudi Arabia is particularly interested in this project because it has a great water shortage. Scientists estimate that it would take 128 days to transport a large iceberg (about 1/2 square mile) to Saudi Arabia. Yet the iceberg would be completely melted by the 104th day. Therefore, insulation would be essential, but how to insulate the iceberg remains an unsolved problem.The problems in transporting an iceberg are numerous. The first problem is choosing the iceberg to pull. The icebergs that form in the North Pole are quite difficult to handle because of their shape. Only a small portion extends above the water — most of the iceberg is below the surface, which would make it difficult to pull. South Pole icebergs, on the other hand, are flat and float like table tops. Thus they would be much easier to move.How can a 200-million-ton iceberg be moved. No ship is strong enough to pull such enormous weight through the water. Perhaps several ships could be used. Attaching ropes to an iceberg this size is also an enormous problem. Engineers think that large nails or long metal rods could be driven into the ice. What would happen if the iceberg splits into several pieces during the pulling. Even if an iceberg with very few cracks were chosen, how could it be pulled through stormy waters. Furthermore, once the iceberg reached its destination, very few ports would be deep enough to store it.All of these problems must be solved before icebergs can become a reasonable source of water. Yet scientists estimate that it will be possible to transport them in the near future. Each year, enough icebergs form to supply the whole world with fresh water for a full year. In addition, icebergs are free and nonpolluting. As a solution to the world’s water problems, icebergs may be a workable possibility.8. What is a problem in transporting iceberg?A. The size of the iceberg.B. The colour of the iceberg.C. The salt in the iceberg.D. The movement of air and water.9. What is the author’ attitude towards transporting iceberg?A. Pessimistic.B. Objective.C. Optimistic.D. Unconcerned.10. What does the last paragraph mainly tell us?A. It is hard to use iceberg.B. Iceberg are a good choice.C. There are problems with iceberg.D. Man finds no other ways to solve water shortage.11. What can be a suitable title for the text?A. Shortage of water.B. Icebergs for water.C. Scientists and icebergs.D. Iceberg—scientists headache.DThursday, two Russian submarines(潜艇) dived down 2.5 miles into the Arctic Ocean and planted a national flag onto a piece of continental shelf known as the Lomonosov Ridge. Rising from the center of the Arctic Basin, the flag sent a clear message to the surrounding nations: Russia had just laid claim(权利) to the vast oil and gas reserves contained in this underwater area.AfterRussia, theUnited States,Norway,SwedenandFinlandare all trying to gain profit. Projections show that the area of land and sea that falls within theArctic Circleis home to an estimated 90 billion barrels of oil, an incredible 13% of Earth’s reserves. It’s also estimated to contain almost a quarter of untapped global gas resources. But long before this oil race began, how did theArcticbecome so rich in energy?“The first thing you realize is that theArctic—unlike the Antarctic—is an ocean surrounded by continents”, Alastair Fraser, a geoscientist from Imperial College London, said. Firstly, this means there’s a huge quantity of organic material available, in the form of dead sea creatures such as plankton and algae, which form the basis of what will ultimately become oil and gas. Secondly, the surrounding ring of continents means that the Arctic Basin contains a high proportion of continental crust(大陆地壳), which makes up about 50% of its oceanic area. That’s significant because continental crust typically contains deep depressions called basins, into which organic matter sinks.Here, it gets inserted in rock and preserved in anoxic(缺氧) waters, meaning they contain little oxygen. “Normally, in a shallow sea with lots of oxygen, it would not be preserved. But if the sea is deep enough, the oxygenated waters at the top will be separated from the anoxic conditions at the base,” Fraser explained. Conserved within these oxygen-free basins, the matter maintains compounds that finally make it useful as an energy source for millions of years in the future.12. Why didRussiaplant a national flag onto the Lomonosov Ridge?A. To tell surrounding countries its armed forces.B. To show its advanced technology of submarines.C. To show abundant natural resources in theArcticBasin.D. To claim its privilege to explore for oil and gas in the area.13. What’s the function of the last sentence in paragraph 2?A. Making a comparison.B. Serving as a connecting link.C. Analyzing the cause and effect.D. Drawing the conclusion of the text.14. What can we know from the last paragraph?A. Oxygen only exists in the top part of the ocean.B. Organic materials mostly exist in the basins with oxygen.C. Water containing oxygen turns organic materials into oil and gas.D. Oxygen-free environment counts in the formation of the arctic’s rich energy.15. What can be a suitable title for the text?A. What makes theArcticattractive?B. Why do many nations focus on theArctic?C. Why is there so much oil in theArctic?D. How does theArcticBasincome into being?第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。
Design of the Temperature Control System Based on AT89S51ABSTRACTThe principle and functions of the temperature control system based on microcontroller AT89S51 a re studied, and the temperature measurement unit consists of the 1-Wire bus digital temperature sensor DS18B20. The system can be expected to detect the preset te mperature, display time and save monitoring data. An alarm will be given by system if the temperat ure exceeds the upper and lower limit value of the temperature which can be set discretionarily and then automatic control is achieved, thus the temperature is achieved monitoring intelligently within a certain range. Basing on principle of the system, it is easy to make a variety of other non-linear control systems so long as the software design is reasonably changed. The system has bee n proved to be accurate, reliable and satisfied through field practice.KEYWORDS: AT89S51; microcontroller; DS18B20; temperatureI. INTRODUCTIONTemperature is a very important parameter in human life. In the modern society, temperature contr ol (TC) is not only used in industrial production, but also widely used in other fields. With the impro vement of the life quality, we can find the TC appliance in hotels, factories and home as well. And t he trend that TC will better serve the whole society, so it is of great significance to measure and co ntrol the temperature.Based on the AT89S51 and temperature sensor DS18B20, this system controls the condition temp erature intelligently. The temperature can be set discretionarily within a certain range. The system can show the time on LCD, and save monitoring data; and automatically control the temperature w hen the condition temperature exceeds the upper and lower limit value. By doing so it is to keep th e temperature unchanged. The system is of high anti-jamming, high control precision and flexible design; it also fits the rugged environment. It is mainly used in people's life to improve the quality of the work and life. It is also versatile, so that it can be convenient to extend the use of the system. So the design is of profound importance. The general design, hardware design and software design of the system are covered.II. SYSTEM GENERAL DESIGNThe hardware block diagram of the TC is shown in Fig. 1. The system hardware includes the micro controller, temperature detection circuit, keyboard control circuit, clock circuit, Display, alarm, drive circuit and external RAM. Based on the AT89S51, the DS18B20 will transfer the temperature signa l detected to digital signal. And the signal is sent to the microcontroller for processing. At last the te mperature value is showed on the LCD 12232F. These steps are used to achieve the temperature detection. Using the keyboard interface chip HD7279 to set the temperature value, using the micro controller to keep a certain temperature, and using the LCD to show the preset value for controlling the temperature. In addition, the clock chip DS1302 is used to show time and the externalRAM 62 64 is used to save the monitoring data. An alarm will be given by buzzer in time if the temperature exceeds the upper and lower limit value of the temperature. III. HARDWARE DESIGN A. Microc ontrollerThe AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S51 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. Minimum system of the microcontroller is shown in Fig. 2. In order to save monitoring data, the 6264 is used as an external RAM. It is a stati c RAM chip, low-power with 8K bytes memory. B. Temperature Detection CircuitThe temperature sensor is the key part in the system. The Dallas DS18B20 is used, which support s the 1-Wire bus interface, and the ON-BOARD Patented is used internally. All the sensor parts and the converting circuit are integrated in integrated circuit like a transistor [1]. Its measure range is -55℃ ~125 ℃, and the precision between -10℃ ~85 ℃ is ±0.5℃ [2 ,3]. The temperature collected by the DS18B20 is transmitted in the 1-Wire bus way, and this highly raises the system anti-jamming and makes it fit in situ temperature measurement of the rugged environment [4].There are two power supply ways for the DS18B20. The first is external power supply: the first pin of the DS18B20 is connected to the ground; the second pin serves as signal wire and the third is c onnected to the power. The second way is parasite power supply [5]. As the parasite power supply will lead to the complexity of the hardware circuit, the difficulty of the software control and the perfo rmance degradation of the chip, etc. But the DS18B20(s) can be connected to the I/O port of the mi crocontroller in the external power supply way and it is more popular. Therefore the external power su pply is used and the second pin is connected to the pin P1.3 of the AT89S51. Actually, if there are multipoint to be detected, the DS18B20(s) can be connected to the 1-Wire bus. But when the number is over 8, there is a concern to the driving and the more complex s oftware design as well as the length of the 1-Wire bus. Normally it is no more than 50m. To achieve distant control, the system can be designed in to a wireless one to break the length limit of the 1-Wire bus [6]. C. LCD CircuitThe LCD 12232F is used, which can be used to show characters, temperature value and time, and supply a friendly display interface. The 12232F is a LCD with 8192 128×32 pixels Chinese charact er database and 128 16×8 pixels ASCII character set graphics. It mainly consists of row drive/colu mn drive and 128×32 full lattice LCD with the function of displaying graphics as well as 7.5×2 Chin ese characters. It is in a parallel or serial mode to connect to external CPU [7]. In order to economi ze the hardware resource, the 12232F should be connected to the AT89S51 in serial mode with on ly 4 output ports used.The LCD grayscale can be changed by adjusting the variable resistor connected the pin Vlcd of the LCD. CLK is used to transmit serial communication clock. SID is used to transmit serial data. CS i s used to enable control the LCD. L+ is used to control the LCD backlight power. D. Clock Circuit The Dallas DS1302 is used, which is a high performance, low-power and real-time clock chip with RAM. The DS1302 serves in the system with calendar clock and is used to mo nitor the time. The time data is read and processed by the AT89S51 and then displayed by the LC D. Also the time can be adjusted by the keyboard.The DS1302 crystal oscillator is set at 32768Hz, and the recommended compensation capacitance is 6pF. The oscillator frequency is lower, so it might be possible not to connect the capacitor, and t his would not make a big difference to the time precision. The backup power supply can be connec ted to a 3.6V rechargeable battery. E. Keyboard Control CircuitThe keyboard interface in the system is driven by the HD7279A which has a +5V single power sup ply and which is connected to the keyboard and display without using any active-device. According to the basic requirements and functions of the system, only 6 buttons are neede d. The system's functions are set by the AT89S51 receiving the entered data. In order to save the external resistor, the 1×6 keyboard is used, and the keyboard codes are defined as: 07H, 0FH, 17 H, 1FH, 27H, 2FH. The order can be read out by reading the code instruction. HD7279A is connec ted to the AT89S51 in serial mode and only 4 ports are need. As shown in Fig. 6, DIG0~DIG5 and DP are respectively the column lines and row line ports of the six keys which achieve keyboard monitoring, decoding and key codes identification. F. Alarm CircuitIn order to simplify the circuit and convenient debugging, a 5V automatic buzzer is used in the alar m circuit [8]. And this make the software programming simplified. As shown in Fig. 7, it is controlled by the PNP transistor 9012 whose base is connected to the pin P2.5 of the AT89S51. When the te mperature exceeds the upper and lower limit value, the P2.5 output low level which makes the tra nsistor be on and then an alarm is given by the buzzer.G. Drive CircuitA step motor is used as the drive device to control the temperature. The four-phase and eight-beat pulse distribution mode is used to drive motor and the simple delay program is used to handle the time interval between the pulses to obtain different rotational speed. There are two output stat es for the step motor. One: when the temperature is over the upper value, the motor rotates revers ely (to low the temperature), while when lower than the lower limit value, the motor rotates normally (to raise the temperature); besides not equals the preset value. Two: when the temperature is at s omewhere between the two ends and equals the preset value, the motor stops. These steps are u sed to achieve the temperature control. In addition, the motor speed can also be adjusted by relative buttons. As shown in Fig. 8, the code data is input through ports A11~A8 (be P2.3~P2.0) of the A T89S51 and inverted output by the inverter 74LS04. Finally it is amplified by thepower amplifier 2803A to power the motor.IV. SOFTWARE DESIGNAccording to the general design requirement and hardware circuit principle of the system, as well a s the improvement of the program readability, transferability and the convenient debugging, the sof tware design is modularized. The system flow mainly includes the following 8 steps: POST (Power-on self-test), system initiation, temperature detection, alarm handling, temperature control, clock chip DS1 302 operation, LCD and keyboard operation. The main program flow is shown in Fig. 9. Give a little analysis to the above 8 tasks, it is easy to find out that the last five tasks require the real time ope ration. But to the temperature detection it can be achieved with timer0 timing 1 second, that is to sa y temperature detection occurs per second. The system initiation includes global variable definition , RAM initiation, special function register initiation and peripheral equipment initiation. Global variab le definition mainly finishes the interface definition of external interface chip connected to the AT89 S51, and special definition of some memory units. RAM initiation mainly refers to RAM processing. For example when the system is electrified the time code will be stored in the internal unit address or the scintillation flag will be cleared. The special function register initiation includes loading the ini tial value of timer and opening the interrupt. For example, when the system is electrified the timer i s initialized. The peripheral equipment initiation refers to set the initial value of peripheral equipmen t. For example, when the system is electrified, the LCD should be initialized, the start-up display should be called, the temperature conversion command should be issued firstly and the clock chip DS1302 should also be initialized. The alarm handling is mainly the lowering and the rai sing of temperature to make the temperatureremain with the preset range. When the temperature is between the upper and the lower limit value , it goes to temperature control handling, that is to say the temperature need to be raised or lowere d according to the preset value. By doing so make the condition temperature equal to the preset va lue and hence to reach the temperature target.V. CONCLUSIONThe temperature control system has the advantages of friendly human-computer interaction interface, simple hardware, low cost, high temperature control precision (error in the range of ±1 ℃), convenience and versatility, etc. It can be widely used in the occasions with -55℃ to 125℃ range, and there is a certain practical value.。
青蒿素英语作文简单Title: The Miracle of Artemisinin: A Breakthrough in Global Health.Artemisinin, a derivative of the sweet wormwood plant (Artemisia annua), has revolutionized the treatment of malaria, a deadly disease that has plagued humanity for centuries. Discovered and developed by Chinese scientists, artemisinin has saved millions of lives worldwide, particularly in malaria-endemic regions where access to effective healthcare is limited.Malaria is caused by parasites transmitted through the bites of infected mosquitoes. These parasites invade red blood cells, multiplying rapidly and causing symptoms such as fever, chills, and fatigue. Left untreated, malaria can lead to severe health complications and even death.Before the advent of artemisinin, the treatment options for malaria were limited and often ineffective. Traditionalantimalarial drugs, such as chloroquine and sulfadoxine-pyrimethamine, had become increasingly ineffective due to the development of parasite resistance. This resistance was a major challenge, as it rendered these drugs unable to eliminate the parasites, allowing the disease to persist and even worsen.The discovery of artemisinin marked a turning point in the fight against malaria. Derived from the Chinese medicinal herb Artemisia annua, artemisinin and its derivatives exhibit remarkable antimalarial activity, targeting the parasite's lifecycle and preventing its multiplication within red blood cells. This unique mechanism of action has made artemisinin an effective treatment even against drug-resistant strains of malaria.The development of artemisinin was a remarkable feat of scientific research. Chinese scientists, led by Tu Youyou, conducted extensive research on traditional Chinese medicinal herbs in search of new antimalarial agents. Through meticulous experiments and clinical trials, they isolated and purified artemisinin from Artemisia annua,demonstrating its remarkable efficacy against malaria.The global impact of artemisinin has been profound. It has become a key component of combination therapies for malaria, significantly improving patient outcomes and reducing the mortality rate from the disease. In areas where malaria is endemic, artemisinin-based combination therapies (ACTs) have been widely adopted as the first-line treatment for malaria, due to their high cure rates and low risk of resistance development.The success of artemisinin has also had a significant economic impact. Malaria-endemic regions often face a沉重的经济负担 due to the disease's impact on workforce productivity, healthcare costs, and lost economic opportunities. The widespread use of ACTs has helped to reduce this burden, improving the economic well-being of communities and nations.Moreover, the development of artemisinin has provided a powerful example of the potential of traditional medicine. By harnessing the knowledge and resources of traditionalmedicine systems, scientists have been able to identify and develop new and effective treatments for modern-day health challenges. This approach offers a promising avenue for future drug discovery, particularly in areas where access to modern healthcare is limited.In conclusion, artemisinin has emerged as a powerful weapon in the fight against malaria. Its remarkable antimalarial activity, unique mechanism of action, and broad spectrum of activity against drug-resistant parasites have transformed the treatment of this deadly disease. The global impact of artemisinin has been profound, saving millions of lives and improving the economic well-being of communities worldwide. As we look to the future, the continued research and development of new antimalarial agents, drawing inspiration from traditional medicine systems, holds the promise of further reducing the burden of malaria and promoting global health and well-being.。
