BASIC Sepsis (August 2006)

拉扎特斯basic id中的s代表来访者认知评估在斯坦福大学的调查中，拉扎特斯basic id中的s代表来访者认知评估。

认知评估的要素包括：事件的顺序性、预期性、执行计划时可信赖的程度、行动与思维之间的关系、活动或情境的一致性等等。

4.1.s 表示评估对象具有与生俱来的适应倾向，他们比不具有该倾向的人更易受到环境因素的影响，更多地依赖他人来帮助自己处理问题，更多地依靠外部的标准和内部的稳定性作出决策。

也就是说，相对于其他人群，具有s基因的人群更可能产生行为退缩的心理。

s基因是人类的基本遗传密码。

4.1.s表示评估对象具有与生俱来的适应倾向，他们比不具有该倾向的人更易受到环境因素的影响，更多地依赖他人来帮助自己处理问题，更多地依靠外部的标准和内部的稳定性作出决策。

也就是说，相对于其他人群，具有s基因的人群更可能产生行为退缩的心理。

s基因是人类的基本遗传密码。

s基因在染色体上存在两个拷贝，它们遵循完全相同的规律，即每隔27-31个核苷酸重复一次。

遗传学研究发现，具有同源的s基因序列的人具有共同的遗传特征，如高度的直觉、机敏、善良等等。

心理学家认为s基因属于纯生物学特征，具有心理学特征的人的基因结构较为简单，而具有心理学特征的人则是生物学特征与心理学特征的“杂交”产品。

一个人的s基因密码是否简单，主要取决于遗传方式。

具有纯生物学特征的人的基因序列很简单，而具有心理学特征的人的基因序列则比较复杂。

这种解释能说明一些实际问题，但仍然有很多疑点。

首先，拉扎特斯调查使用的是被试者的基因序列数据，但并没有区分纯生物学特征和心理学特征，如果我们把s基因的表现作为判断的标准，似乎并不科学。

其次，我们无法证明s基因简单的人更可能产生行为退缩。

美国著名心理学家塞利格曼（ seligman）认为，行为的适应性决定于三种基本的刺激加工过程，即感觉输入、过滤加工和储存加工。

其中，储存加工可以保持信息不随时间流失，从而决定了记忆是否可以长久地保存。

Digest Of The. Economist. 2006(4-5)Hot to trotA new serv ice hop es to do for texting what Skype did for voice callsTALK is cheap—particularly since the appearance of voice-over-internet se rvices such as Skype. Such services, which make possible very cheap (or even free) calls by rou ting part or all of each call over the interne t, have forced traditional telecoms firms to cut their prices. And now the same thing could be about to happen to mobilephone text mess ages, following the launch this week of Hotxt, a Britis h start-up.Users download the Hotxt software to their handsets, just as they would a game or a ringtone. They choose a user name, and can then exchange as many messages as they like with other Hotxt users for £1 ($1.75) per week. The messages are sent as data packe ts across the internet, rather than being rou ted through operators' textmessaging infras tructu re. As a resul t, users pay only a tiny data-transport charge, typically of a penny or so per mess age. Since text messages typically cost 10p, this is a big saving—particula rly for the cost-conscious teenagers at whom the service is aimed.Most teenagers in Britain, and elsewhere in Europe, pay for their mobile phones on a “pre-paid” basis, rather than having a monthly contract with a regular bill. Pre-paid tariffs are far more expensive: bu ndles of free texts and other special deals, which can reduce the cost of text messaging, are generally not available. For a teenager who sends seven messages a day, Hotxt can cut the cost of texting by 75%, saving £210 per year, sa ys Doug Richard, the firm's co-fou nder. For really intensi ve text-messagers, the savings could be even bigger: Josh Dhaliwal of mobileYouth, a market-research firm, says that some teenagers—chiefly boys aged 15-16 and girls aged 14-15— are “supertexters” who send as many as 50 mess ages per day.While this sounds like good news for users, it could prove painful for mobile operators. Text-mess aging accou nts for around 20% of a typical operator's revenues. With margi ns on text messages in excess of 90%, texting also accou nts for nearly half of an operator's profits. Mr Ri chard is confident that there is no legal way that operators can block his service; they could raisedata-transport costs, but that w ould undermine their own efforts to pus h new services. Hotxt plans to launch in other cou ntries soon.“The challenge is getting that initial momentu m,” says Mr Dhaliwal. Hotxt needs to persuade people to sign up, so that they will persuade their friends to sign up, and so on. Unlike Skype, Hotxt is not free, so users may be less inclined to give it a try. Bu t as Skype has also shown, once a disru ptive, low-cost communications service starts to spread, it can quickly become very big indeed. And that in turn can lead to lower prices, not jus t for its users, bu t for everyone.A discerning viewA new way of processing X-rays gives much clear er imagesX-RAYS are the mysterious phenomenon for which Wilhelm Röntge n was awarded the first Nobel prize in physics, in 1901. Since then, they have shed their mystery and found widespread use in medici ne and industry, where they are used to revealthe inner properties of solid b odies.Some properties, however, are more easily discerned than others. Conventional Xray imagi ng relies on the fact that different materials abs orb the radia tion to different deg rees. In a medical context, for example, bones absorb X-rays readily, and so show up white on an X-radiograph, which is a photog raphic neg ative. But Xrays are less g ood at discriminating between different forms of soft tissue, such as muscles, tend ons, fat and blood vessels. That, however, could soon change. For Franz Pfeiffer of the Paul Scherrer Institu te in Villigen, Switzerland, and his colleagues report, in the April edition of N ature Physics, that they have manipulated s tandard X-ray imagi ng techniques to show many more details of the inner body.The trick needed to discern this fine detail, according to Dr Pfeiffer, is a simple one. The researchers took advantage not only of how tissues absorb X-rays bu t also of how much they slow their passage. This slowing can be seen as changes in the phase of the radiation that emerges—in other words of the relative posi tions of the peaks and troughs of the waves of which X-rays are composed.Subtle changes in phase are easil y picked up, so doctors can de tect even small variations in the composi tion of the tissue under investigation, such as might be caused by the early stages of breast cancer. Indeed, this trick—known as phase-contras t imaging—is already used rou tinely in optical microscopy and transmission electron microscopy. Until now, however, no one had thou ght to use it for medical X-radiography.To perform their trick, the researchers used a series of three devices called transmission gratings. They placed one between the source of the X-rays and the body u nder examination, and two be tween the body and the X-ray detector that forms the image. The first grating gathers information on the phases of the X-rays passing through it. The second and third work together to produce thedetailed phase-contrasted image. The approach generates two separate images—the classic X-ray image and the phase-contras ted image—which can then be combined to produce a hig h-resolu tion picture.The researchers tested their technique on a C ardinal tetra, a tiny iridesc ent fish commonly fou nd in fish tanks and aquariums. The conventional X-ray image showed the bones and the gu t of the fish, w hile the phase-contrasted image showed details of the fins, the ear and the eye.Dr Pfeiffer's technique would thus appear to offer a way to get much greater de tail for the same amount of radiation exposure. Moreover, since it uses standard hospital equipment, it should be easy to introduce into medical practice. X-rays may no long er b e the s tuff of Nob el prizes, but their usefulness may just have increased sig nificantly.Here be dragonsWith luck, you may soon be able to buy a mythological petPAOLO FRIL, chairman and chief scientific officer of GeneDu pe, based in San Melito, California, is a man with a dream. That dream is a d ragon in every home.GeneDu pe's business is biotech pets. Not for Dr Fril, though, the mundane cloning of dead moggies and pooches. He plans a range of entirely new animals—or, rather, of really qui te old animals, with the twist that even when they did exis t, it was only in the imagination.Making a mythical creature real is not easy. Bu t GeneDu pe's team of bi ologis ts and compu ter scientists reckon they are equal to the task. Their secret is a new field, which they call “virtual cell biology”.Biology and computing have a lot in common, si nce both are about processing information—in one case electronic; in the other, bi ochemical. Virtual cell biology as pires to make a software model of a cell that is accurate in every biochemical detail. That is possible because all animal cells use the same parts lis t—mitochondria for energ y processing, the end oplasmic reticulu m for making proteins, Golgi body for protein asse mbly, and so on.Armed with their virtu al cell, GeneDupe's scientis ts can customise the result so that it belongs to a particular species, byloadi ng it with a virtual copy of that animal's genome. Then, if the cell is also loaded with the rig ht virtual molecules, it will behave like a fertilised egg, and start dividi ng and developing—first into an embryo, and ultimately into an adult.Because this “growth” is going on in a compu ter, it happens fast. Passi ng from egg to adult in one of GeneDu pe's enormous Mythmaker computers takes less than a minu te. And it is here that Charles Darwin gets a look in. With such a short generation time, GeneDu pe's scientis ts can add a little evolu tion to their products.Each compu ter starts with a search image (dragon, unicorn, gryphon, etc), and the genome of the real animal most closely resembling it (a lizard for the dragon, a horse for the unicorn and, most taxingly, the spliced genomes of a lion and an eag le for the gryphon). The virtual genomes of these real animals are then tweaked b y random electronic mu tations. When they have matu red, the virtual adults most closely resembling the targets are picked and cross-bred, while the others are cull ed.Using this rapid evolu tionary process, GeneDu pe's scientis ts have arrived at genomes for a range of mythological creatures—in a computer, at least. The next stage, on w hich they are jus t embarking, is to do it for real.This involves synthesising, wi th actual DNA, the genetic material that the compu ter mod els predict will produce the mythical creatures. The synthetic DNA is then inserted into a cell that has had its natural nu cleus removed. The resul t, Dr Fril and his commercial backers hope, will be a real live dragon, unicorn or w hat have you.T ales of the unexpectedWhy a drug trial went so badly wrongIN ANY sort of test, not least a drugs trial, one should expect the u nexpected. Even so, on March 13th, si x volunteers taking part in a small clinical trial of a treatment known as TGN1412 got far more than they bargained for. All end ed up seriousl y ill, with multiple organ failure, soon after being injected with the drug at a special testing unit at Northwick Park Hospital in London, run by a company called Parexel. One man remains ill in hospital.Small, preliminary trials of this sort are intended to find ou t whether a drug is toxic. Nevertheless, the mishap was so serious that Britain's Medicines and Healthcare products Regulatory Agency (MHRA), a government body, swiftly launched a fu ll inquiry. On April 5th it announced its preliminary findings. These were that the trial was run correctly, doses of the drug were given as they were supposed to have been, and there was no contamination during manufacturing. In other words, it seems that despite extensive tests on animals and hu man-cell cultures, and des pite the fact that the doses in the hu man trial were only a five-hundredth of those given to the animals, TGN1412 is toxic in people in a way that simply had not shown up.This is a difficult resul t for the drug business because it raises questions ab ou t the right way of testing medicines of this kind. TGN1412 is u nusual in that it is an antib ody. Most drugs are w hat are known as “small molecules”. Antib odies are big, powerful proteins tha t are the workhorses of the immune system. A mere 20 of them have been approved for hu man therapy, or are in latestage clinical trails, in America and Europe, bu t hundreds are in pre-clinical development, and will soon need to be tried out on people.Most antibody d rugs are desig ned to work in one of three ways: b y recruiting parts of the immune system to kill cancer cells; by delivering a small-molecul e drug or a radi oactive atom specifically to a cancer; or by blocking unwanted immune responses. In that sense, TGN1412 was u nusual because it worked in a fourth way. It is what is called a “superag onis tic” antib ody, desi gned to increase the numbers of a type of immune cell know n as regulatory T-cells.Reduced numbers, or impaired function, of regulatory T-cells has been implicated in a nu mber of illnesses, such as type 1 diabetes, multiple sclerosis and rheumatoid arthritis. Boosting the pool of these antib odies seemed li ke a g ood treatment strateg y. Unfortu nately, that strategy fell disastrousl y to pieces and it will take a little longer to find ou t why.The resul t highlights concerns raised in a paper jus t published by the Academy of Medical Sciences, a g rou p of experts b ased in Lond on. It says there are special ris ks associated with novel antib ody therapies. For example, their chemical specificity means that the y might not bind to their targets in hu mans as they do in other species.Accidence and substanceT wo possib le exp lanations for the bulk of realityTHE unknown pervades the universe. That which people can see, with the aid of various s orts of teles cope, accounts for just 4% of the total mass. The rest, however, mus t exis t. Withou t it, galaxies would not survive and the universe would not be gently expanding, as witnessed by as tronomers. What exactly constitutes this dark matter and dark energy remains mysterious, but physicists have recently u ncovered some more clues, ab out the former, at least.One possible explanation for dark matter is a group of subatomic particles called neutrinos. These objects are so difficult to catch that a screen made of lead a light-year thick would stop only half the neu trinos beamed at it from getting through. Yetneu trinos are thoug ht to be the most abundant particles in the universe. Some ten thousand trillion trillion—most of them produced by nuclear reactions in the sun—reach Earth every second. All bu t a handful pass straight through the planet as if it wasn't there.According to the Standard Model, the most successful description of particle physi cs to date, neutrinos come in three varieties, called “flavours”. These are know n as electron neu trinos, tau neu trinos and muon neu trinos. Ag ain, according to the StandardMod el, they are point-like, electrically neu tral and massless. Bu t in recent years, this view has been challenged, as physicists realis ed that neu trinos might have mass.The first strong evidence came in 1998, when researchers at an experiment called SuperKamiokande, based at Kamioka, in Japan, showed that muon neu trinos produced by cosmic rays hitting the upper atmosphere had g one missing by the time they should have reached an underground detector. SuperKamiokande's operators suspect that the missing muon neu trinos had changed flavour, becoming electron neutrinos or—more likely—tau neutrinos. Theory suggests that this process, called oscillation, can happen only if neu trinos have mass.Since then, there have been other reports of oscillation. Results from the Sudbury Neutrino Obse rvatory in Canada suggest that electron neutrinos produced b y nuclear reactions in the sun change into either muon or tau neu trinos on their jou rney to Earth. Tw o other Japanese experiments, one conducted at Kamioka and one involving the KEK particle-accelerator lab oratory in Tsukuba, near Tokyo, also hint at oscillation.Last week, researchers working on the MINOS experiment at Fermilab, near C hicago, confirmed these resul ts. Over the coming months and years, they hope to produce the most accurate measurements yet. The researchers created a beam of muonneu trinos b y firing an intense stream of protons into a bl ock of carbon. On the other side of the target sat a particle detector that monitored the number of muon neutrinos leaving the Fermilab si te. The neu trinos then traveled 750km (450 miles) through the Earth to a detector in a former iron mine in Soudan, Mi nnesota.Myths and migrationDo immigrants really hurt A merican wor kers' wages?EVERY now and again America, a nation largely made up of immigrants and their descendants, is gripped by a furious political row over whether and how it should stem the flood of people wanting to enter the country. It is in the mids t of just such a quarrel now. C ongress is contemplating the erection of a wall along stretches of the Mexican border and a crackdown on illegalworkers, as well as softer policies such as a guest-w orker programme for illegal immigrants. Some of the arguments are plain silly. Immig ration's defenders claim tha t foreigners come to do jobs tha t Americans won't—as if ci ties with few immigrants had no gardeners. Its opponents say that immigrants steal American jobs—succu mbing to the fallacy that there are only a fixed number of jobs to g o around.One common argu ment, though not silly, is often overstated: that immigration pushes down American workers' wages, especially among high-school dropouts. It isn't hard to see why this might be. Over the past 25 years American incomes have become less equally dis tribu ted, typical wages have grown surprisingly sl owly for such a healthy economy and the real wages of the least skilled have actua lly fallen. It is plausible that immigration is at least partly to blame, especially be cause recent arrivals have disproportionately poor skills. In the 2000 census immigrants made up 13% of A merica's pool of workers, but 28% of those withou t a high-school education and over half of those with eig ht years' schooling or less.In fac t, the relationship be tween immigration and wages is not clear-cut, even in theory. That is because wages depend on the supply of capi tal as well as lab our. Alone, an influx of immigrants raises the supply of workers and hence reduces wages. But cheaper labour increases the potential retu rn to employers of building new factories or opening new valet-parking companies. In so doing, they create extra demand for workers. Once capital has fully adjusted, the final impact on overall wages should be a wash, as long as the immigrants have not changed the productivity of the workforce as a whole.However, even if wages do not change on average, immigration can s till shift the relative pay of workers of di fferent types. A large inflow of low-skilled people could pus h down the relative wages of low-skilled natives, assuming that they compete for the same jobs. On the other hand, if the immigrants had compleme ntary skills, natives would be relatively be tter off. To gauge the full effect of immigration on wages, therefore, you need to know how quickly capital adjusts and how far the newcomers are substitutes for local workers.Roaming holidayT he EU hopes to slash the price of cross-border mobile calls“TODAY it is only when usi ng your mobile phone abroad that you realis e there are still borders in Europe,” lamented Viviane Reding, the European commissioner responsible for telecoms and media regulation, as she annou nced plans to slash the cost of mobile roaming last month. It is a laudable aim: Eu ropean consumers typically pay €1.25 ($1.50) per minute to call home from another European country, and €1 per minute to receive calls from home while abroad. With roa ming margi ns ab ove 90%, European mobile operators make profits of arou nd €10 billi on a year from the trade, the commission estimates.Ms Reding's plan, unveiled on March 28th and up for discussion until May 12th, is to impose a “home pricing” scheme. Even while roaming, callers would be charged whatever they would normally pay to use their phones in their home cou ntries; charges for incoming calls while roaming would be abolished. That may sou nd good. But, as the industry is understandabl y at pains to point out, it could have some curious knock-on effects.In particular, consumers could sign up with operators in foreign countries to take advantage of lower prices. Everyone w ould take out subscriptions to the cheapest supplier and bring them back home, says John Tysoe of the Mobile World, a consultancy. “You'd end up with a complete muddle. An operator mig ht have a netw ork, but no customers, because they'v e all migrated.”Another problem with Ms Reding's plan, he says, is that operators would compensate for the loss of roaming fees— thou ght to account for arou nd 3% of their revenues and 5% of profits—by raising prices elsewhere. This would have the perverse effect of lowering prices for international business travellers, a big chunk of roaming traffic, while raising prices for most consumers.The commission's proposals are “economically incoherent”, says Richard Feasey of Vodafone, which operates mobile networks in many European countries. Imposi ng price caps on roaming is legally questionable, he says, and Vodafone has, in any case, been steadil y reducing its roaming charges. (European regulators prevented it from doing so for three years on antitrust grounds after its takeover of Mannesmann in 2000.) Orange, another multinational operator, says it is planning to make price cu ts, too. “Of course, now everybody's got price cuts,” says Stefano Nicoletti of Ovu m, a consultancy.But perhaps Ms Reding's unspoken plan is to use the threat of regulation as a way to prompt action. Operators are rig ht that her proposals make no sense, but they are charging too much all the sa me. So expect them to lobb y hard against the proposals over the next cou ple of years, while quietly cutting their prices—an outcome tha t would, of course, allow both sid es to claim victory.Dev ices and their desiresE ngineers and chemists get togetherTHERE used to be a world of difference between treating a patient with a de vice—such as a fake hip or a pacemaker—and using biolog y and biochemistry. Different ailments required wholly di fferent treatments, often with little in common. Bu t that is changing as medical advances—such as those being trumpeted at the biotechnolog y industry's annual gathering this week in Chicago—foster combinations of su rgical implants and other hardware with support from medicines. Drug-releasi ng stents were one of the first fruits of this trend, which increasingly requires vastly different sorts of health-care firms to mesh their research efforts.That will be a challenge. While pharmaceu tical and biotech firms are always in search of the next big thing, devicemakers prefer g radual progress. Instead of hanging ou t with b reathless entrepreneu rs near America's east and west coasts, where most drug and biotechnology firms are bas ed, many of the device-makers huddle in midwestern cities such as Minneapolis, Indianapolis and Kalamazoo. And u nlike Big Pharma, which uses marketing bli tzes to tell ailing consu mers ab ou t its new drugs, medical-device sales teams ac t more as instructors, showing doctors how to install their latest creations.Several companies, however, are now trying to bring these two busi ness cultu res together. Earlier this year, for example,Angi otech Pharmaceuticals, a C anadian firm, bought American Medical Instruments (AMI). Angiotech's managers reckon their company has devised a good way to apply d rug coatings to all sorts of medical paraphernalia, from su tures and syringes to catheters, in ord er to reduce the shock to the body. AMI makes just the sorts of medical supplies to which Angiotech hopes to apply its techniques.One of America's biggest makers of medical devices, Medtronic, has been doing joint research with Genzyme, a biotechnology company that is also keen on broade r approaches to health care. Genzyme sa ys that it was looking for better ways to treat ailments, such as coronary and kidney diseas e, and realised that it needed to u nderstand better how electro-mechanical devices and information technology work. Bu t combining its efforts with those of Medtronic “on a cultural level is very hard”, the company says. Biotechnology firms are used to much more risky projects and far longer de velopment cycles.Another difference is that device-makers know that if a problem emerges with their hardware, the engineers will tinker around and try to resolve the glitch. Biotech and pharmaceu tical firms have no such option. If a difficul ty emerges after years of developing and testing a new pill, as with Merck's Vioxx, there may be little they can d o abou t it. “You can't fu tz with a molecul e”, says Debbie Wang, a health-care indus try analyst.Strangely, says Ms Wang, some of the most promising engineering ou tfits were once divisi ons of pharmaceu tical andhealth-care companies, which got rid of them precisely because they did not appear to offer the rapid growth that managers saw in prescription drugs. Guidant, a maker of various cardiovascular devices, was spun off by Eli Lilly in 1994 and a decade later became the prize in a bidding war between Johnson & Johnson and Boston Scientific, which Boston won earlier this year.Pfizer sold How medica, which makes joint replacements and prosthetics, to Kalamazoo-based S tryker in 1998. Anotherjoint-replacement maker, Zimmer, was spun off from B ristol-Myers Squibb in 2001. N ow both those companies are looking for ways to add “anti-interactive coatings”—ie, d rugs—to their business. One of the most troublesome complications in joint replacement is infection.The big drug companies might be tempted to reacquire the firms that they let go. Bu t, given the potential for cultural and strategic clashes, it may make more sense for a few big and broad medical-device makers, such as Med tronic, Boston Scientific and St Jude Medical, to continue consolidating their own industry while co-operating, along the lines of the Med tronic-Genzyme venture, with biotech and pharmaceu tical firms as they see fit. There would still be irritation; bu t probabl y less risk of wholesale rejec tion.E at less, liv e moreHow to liv e longer—maybeDIETING, accordi ng to an old joke, may not actu ally make you li ve longer, but it sure feels that way. Nevertheless, evidence has been accumulating since the 1930s that calorie res triction—reducing an animal's energy intake below its energ y expenditure—extends lifespan and delays the onset of age-related diseases in rats, d ogs, fish and monkeys. Such resul ts have inspired thousands of people to put up with constant hunger in the hope of living longer, healthier lives. They have also led to a search for drugs that mimic the effects of calorie restriction withou t the pain of going on an actu al diet.Amid the hype, it is easy to forget that no one has until now show n that calorie restriction works in humans. That omission, however, changed this month, wi th the publication of the initial results of the first systematic investigation into the matter. Thisstudy, known as C ALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy), was sponsored by America's National Institu tes of Health. It took 48 men and women aged between 25 and 50 and assigned them randomly to either a control group or a calorie-res triction regi me. Those in the second group were required to cu t their calorie intake for six months to 75% of that needed to maintain their weight.The CALERIE study is a landmark in the history of the field, be cause its subjects were either of normal weight or only sli ghtly overweig ht. Previous projects have used individuals who were clinically obese, thus confusi ng the unquestionable benefits to health of reducing obesity with the possible advantages of calorie res triction to the otherwise healthy.At a molecular level, CALERIE suggests these advantages are real. For example, those on restricted diets had lower insulin resistance (hig h resistance is a ris k factor for type 2 diabetes) and lower levels of low-densi ty lipoprotein cholesterol (high levels are a risk factor for heart disease). They showed drops in bod y temperature and blood-insulin levels—both phenomena that have been seen in long-lived, calorie-restricted animals. They also suffered less oxidative damage to their DNA.Eric Ravussin, of Louisiana State Universi ty in Baton Rouge, who is one of the s tudy's authors, says that such results provide support for the theory that calorie restriction produces a metab olic adaptation over and above that which would be expected from weight loss alone. (He also points ou t tha t it will be a long time before such work reveals whether calorie res triction actu ally extends life.) Nevertheless, such metabolic adaptation could be the reas on why calorie res triction is associated with longer lifespans in other animals—and that is certainly the hope of those who, for the past 15 years, have been searching for ways of triggering that metabolic adaptation by means other than semi-starvation.The search for a d rug tha t will stave off old ag e is itself as old as the hills—as is the wis hful thinking of the suckers who finance such efforts. Those who hope to find it by mimicking the effect of calorie restriction are not, however, complete snake-oil salesmen, for there is know n to be a family of enzymes called sirtui ns, which act both as sensors of nu trient availability and as regulators of metabolic rate. These might provide the necessary biochemical link between starving and living longer.Univ ersal serv ice?Proponents of “softwar e as a service” say it w ill wipe out traditional softwareSOMETHING momentous is happening in the software business. Bill Gates of Microsoft calls it “the next sea change”. Analysts call it a “tectonic shift” in the industry. Trade publications hail it as “the next big thing”. It is software-as-a-service (SaaS)—the delivery of software as an internet-bas ed service via a web browser, rather than as a product that mus t be purchased, installed and maintained. The appeal is ob vious: SaaS is quicker, easier and cheaper to deploy than tradi tional software, which means technology budgets can be focused on providing competitive advantage, rather than maintenance.This has prompted an outb reak of iconoclasm. “Traditional s oftware is dead,” says Jas on Maynard, an analyst at Credi t Suisse. Just as most firms do not ow n generators, bu t buy electricity from the grid, so in fu ture they will buy software on the hoof, he says. “It's the end of software as we know it. All software is becoming a service,” declares Marc B enioff of , thebest-known proponent of the idea. But while S aaS is growing fast, it still represents only a tiny fraction of the overall software industry—a mere $3.35 billi on last year, estimates Mr Maynard. Most observers expect it to be worth around $12 billi on by 2010—bu t even that is equal only to Microsoft's quarterly sales today. There is no denying that SaaS is coming. Bu t there is much debate, even among its ad vocates, about how quickly it will g row, and how widely it will be adopted.At the moment, small and medium-sized businesses are the most enthusias tic adopters of SaaS, since it is cheaper and simpler than maintaining rooms of server computers and employing staff to keep them running. Unlike the market for desktop software, which is dominated b y Microsoft, or for high-end enterprise software, which is dominated by SAP and Oracle, the middle grou nd is still hig hly fragmented, which presents an opportunity. “This is the last great software market left—the las t unconsolidated market,” says Zach Nelson of NetSuite, which provides a suite of software services including accou nting, sales-force automation and customer service. His firm is targeting small and mediu m-si zed businesses by providing “verticalised” services—that is, versions of its software adapted to particular types of company, such as professional-service firms, wholesale dis tributors and software firms.Larg e companies, says Mr Nels on, have already made big investments in traditional software. “The y'v e alread y been through the pain,” he says. So they will not be in a hu rry to ditch their exis ting investments in traditional software from the likes of SAP and Oracle. “I have no fantasy of replacing those guys,” says Mr Nelson. Bu t Mr Benioff of disagrees. His firm provides customer-relationship management (CR M) software as a service, which is already used by many big firms including Cisco, Sprint and Merrill Lynch. “The world's larges t companies are now using s for the world's larges t CR M implementations,” he says. “It's the fu ture of our industry that everything will be a service.”Even so, Mr Maynard reckons it will be some time before large companies fully embrace the service mod el. H owever,。

·专家论坛·—休克治疗的困惑液体复苏与肺水肿——杨毅邱海波休克是外科患者常见的临床综合征，早期积极干预治疗有利于改善患者预后。

有效循环血量减少是休克的核心病理生理过程，恢复有效循环血量是治疗休克的首要任务，液体复苏在休克治疗中具有重要作用。

但是外科患者由于手术、创伤以及休克的打击，毛细血管通透性明显增加，液体复苏在恢复有效循环血量、改善器官灌注的同时，也可能导致组织水肿。

临床上经常遇到这样的休克患者，经过积极液体复苏后循环维持，但患者出现肺水肿或呼吸衰竭，严重时导致多器官功能衰竭。

因此，外科休克的液体复苏是一把“双刃剑”，也是困惑临床医生的难题。

临床医生必须在液体复苏维持有效循环血量的同时避免肺水肿，力求在两者之间寻找平衡。

一、早期充分液体复苏在休克治疗中的重要地位充分液体复苏是逆转休克患者有效循环血量不足，防治多器官功能障碍综合征（MODS）的重要和必要手段[1]。

液体复苏的初期目标是保证足够的组织灌注，一旦临床诊断休克，应尽快积极液体复苏。

在感染性休克患者早期目标导向性治疗（early goal-directed therapy,EGDT）的研究中，以早期充分液体复苏为基本手段，如能在严重感染发生6h内实现复苏目标，其28d病死率降低约16%，60d病死率降低约13%[2]。

这一研究确定了感染性休克早期充分液体复苏的重要作用，同时也为早期液体复苏提出了具体的目标，成为国际休克治疗指南的重要组成部分。

通过积极液体复苏，力争休克患者6h内达到复苏目标，包括维持：CVP8～12mm Hg；平均动脉压＞65mm Hg；尿量＞0.5ml·kg-1·h-1；中心静脉血氧饱和度（ScvO2）或混合静脉血氧饱和度（SvO2）＞70%。

若液体复苏后CVP达8～2mm Hg，而ScvO2或SvO2仍未达到70%，需输注浓缩红细胞使血细胞压积达到30%以上，或输注多巴酚丁胺。

Cluster Computing 9,19–27,2006C 2006Springer Science +Business Media,Inc.Manufactured in The UnitedStates.SESAME:Scalable,Environment Sensitive Access Management EngineGUANGSEN ZHANG and MANISH PARASHARThe Applied Software Systems Laboratory (TASSL),Dept.of Electrical and Computer Engineering,Rutgers University,94Brett Road,Piscataway,NJ 08854Abstract.As computing technology becomes more pervasive and mobile services are deployed,applications will need flexible access controlmechanisms.Although lots of researches have been done on access control,these efforts focus on relatively static scenarios where access depends on identity of the subject.They do not address access control issues for pervasive applications where the access privileges of a subject not only depend on its identity but also on its current context and state.In this paper,we present the SESAME dynamic context-aware access control mechanism for pervasive applications.SESAME complements current authorization mechanisms to dynamically grant and adapt permissions to users based on their current context.The underlying dynamic role based access control (DRBAC)model extends the classic role based access control (RBAC).We also present a prototype implementation of SESAME and DRBAC with the Discover computational collaboratory and an experimental evaluation of its overheads.Keywords:security,access control,context-aware,pervasive computing,role based1.IntroductionPervasive computing and communication technologies are rapidly weaving themselves into the fabrics of everyday life and have the potential for fundamentally redefining the way we interact with information,each other,and the world around us.The proliferation of smart gadgets,mobile devices,PDAs and sensors has enabled the construction of pervasive comput-ing environments,transforming regular physical spaces into intelligent spaces [7].Such intelligent spaces provide services and resources that users can access and interact with via per-sonal portable devices such as a PDA using short-range wire-less communications such as Bluetooth or IEEE 802.11.The resulting anytime-anywhere access infrastructures is enabling a new generation of applications that can leverage this per-vasive information Grid to continuously manage,adapt and optimize.One example of such an application is the Aware Home project at Georgia Institute of Technology [10].Sen-sors in the home can capture,process and store a variety of information about its residents and their activities,enabling the Aware Home application to detect and respond to events in the room.Another application is the Intelligent Room project at MIT.In this application,computers are embedded in a room so that people can interact with computers the way they do with other people,using speech,gesture,movement and con-text [14].Other applications are described in [4,9].Such pervasive applications are characterized by continuous perva-sive access to information,resources and services and ad hoc,dynamic interactions between participating entities,and lead to significant research challenges.One key challenge in pervasive applications is managing security and access control.Access Control List (ACL)is a very commonly used access control mechanism.In this ap-proach,permission to access resources or services is moder-ated by checking for membership in the access control list associated with each object.However,this strategy is inade-quate for pervasive applications as it does not consider con-text information.In a pervasive environment,users are mobile and typically access resources (information,services,sensors,etc.)using mobile devices.As a result the context of a user (i.e.location,time,system resources,network state,network security configuration,etc.)is highly dynamic,and granting a user access without taking the user’s current context into account can compromise security as the user’s access privi-leges not only depend on “who the user is”but also on “where the user is”and “what is the user’s state and the state of the user’s environment”.As a result,even an authorized user can damage the system as the system may have different secu-rity requirement within different contexts.Traditional access control mechanisms such as access control list break down in such an environments and a fine-grained access control mech-anism that changes the privilege of a user dynamically based on context information is required.Although a lot of work has been done in the area of ac-cess control,most of this work is user-centric,where only credentials of the user are considered when granting access permission.Relatively little research has been done to com-bine context information with credentials while making ac-cess control decisions.The existing research however does not address pervasive applications where context is dynamic and a user’s privileges must continuously adapt based on the context.This paper presents a dynamic context-aware access con-trol mechanism that dynamically grants and adapts permis-sions to users according to current context.The proposed mechanism extends the role based access control (RBAC)model [3],while retaining its advantages (i.e.ability to define and manage complex security policies).The model dynami-cally adjusts Role Assignments and Permission Assignments based on context information.In our approach,each user is assigned a role subset (by the authority service)from the en-tire role set.Similarly the resource has permission subsets for20ZHANG AND PARASHAR each role that will access the resource.During a secure in-teraction,state machines are maintained by delegated accesscontrol agents at the subject(Role State Machine)to navigatethe role subset,and the object(Permission State Machine)tonavigate the permission subset for each active role.The statemachine consists of state variables(role,permission),whichencode its state,and commands,which transform its state.These state machines define the currently active role and itsassigned permissions and navigate the role/permission subsetsto react to changes in the context.The rest of this paper is organized as follows:Section2presents background and related work.Section3outlines amotivating application.Section4presents the proposed dy-namic context-aware access control model.Section6presentsa short discussion about the model and its implementation.Section7concludes the paper.2.Background and related workRole based access control(RBAC)[3,16]is an alternative totraditional discretionary(DAC)and mandatory access control(MAC).In RBAC,users are assigned roles and roles are as-signed permissions.A principle motivation behind RBAC isthe ability to specify and enforce enterprise specific securitypolicies in a way that maps naturally to an organization’s struc-ture.As user/role associations change more frequently thenrole/permission associations,in most organizations,RBACresults in reduced administrative costs as compared to asso-ciating users directly with permissions.It can be shown thatthe cost of administrating RBAC is proportional to U+Pwhile the cost of associating users directly with permissionsis proportional to U∗P,where U is the number of individualsin a role and P is the number of permissions required by therole.Sandhu et al.[3,16]define a comprehensive frameworkfor RBAC models which are characterized as follows:r RBAC:the basic model with users associated with rolesand roles associated with permissions.r RBAC1:RBAC0with role hierarchies.r RBAC2:RBAC1with constraints on user/role,role/role, and/or role/permission associations.Recently RBAC was found to be the most attractive so-lution for providing security features in different distributed computing infrastructure[16].Although the RBAC models vary from very simple to pretty complex,they all share the same basic structure of subject,role and privilege.Other fac-tors such as relationship,time and location,which may be part of an access decision,are not considered in making ac-cess control decision in these models.In this paper,we extend RBAC0to provide context-aware access control mechanisms for pervasive applications.Giuri and Iglio[5]have proposed a role-based access con-trol model that provides special mechanisms for the definition of content-based access control policies.By extending the no-tion of permission,they have allowed for the specification of security policies in which the permission of an object may depend on the content of the object itself.For example,in a health-care organization,the physician is only allowed to access and modify patient records related to his or her patient.Woo and Lam[19]designed a distributed authorization service using their Generalized Access Control Language (GACL).In their design,they use the notion of system load as the determining factor in certain access control decisions, so that,for example,certain programs can only be executed when there is enough system capacity available.Finally,Michael J.Covington et al.[10,11]have proposed the Generalized Role Based Access Control(GRBAC)model. In this model,they extend the traditional RBAC by applying the roles to all the entities in a system.(In RBAC,the role concept is only used for subjects).By defining three types of roles,i.e.,Subject roles,Environment roles,and Object roles, GRBAC uses context-information as a factor in making access decisions.All of the research efforts described above take additional factors into consideration when make access control decision. However,both Giuri,Iglio and Woo,Lam don’t consider con-text information as a key factor in their access control mech-anism.In GRBAC,the definition of environment roles allows the model to partially address problem we described,but it may not be feasible in practice because the potential large amount of environment roles make the system hard to main-tain.Also,by defining too many roles in the system,it loses the advantage that RBAC provides.3.Access control challenges for pervasive applications To illustrate the motivation of our research,let us discuss an ex-ample application that will be enabled by a pervasive comput-ing infrastructure in a smart building of a university,as illus-trated infigure1.The building has many rooms including fac-ulty offices,administration offices,conference rooms,class-rooms and laboratories.Sensors in the building can capture, process and store a variety of information about the building, the users and their activities.Pervasive applications in such an environment allow faculty,staff,students andadministratorsFigure1.Smart building application.SCALABLE,ENVIRONMENT SENSITIVE ACCESS MANAGEMENT ENGINE21to access resources/information from any locations at anytime while inside this building using mobile devices(PDAs)and wireless networks.While user credentials are still the basis for all the access control decisions,user’s context information and application state should also be considered.For exam-ple,a student can only control the audio/video equipment in a classroom if she/he is scheduled to present in that class at that time by the faculty in charge.Similarly the payroll server should not be allowed to access if its load is above80%or if the access is over an insecure link.In such applications,privileges assigned to the user will change as context changes.If the user is accessing the resource while the user’s context information is changing(say the moves from a secure network link to an insecure link),specific access control mechanisms are needed to ensure that system/application security and consistency are maintained without decreasingflexibility.The examples above embody many of the key ideas of the research presented in this paper.To maintain system security for such a pervasive application,we have to dynamically adapt access permissions granted to users as context information for the session changes.Context information here includes envi-ronment of the user such as location,time that the user access the resource and system information such as CPU usage and network bandwidth.The traditional RBAC models[3]do not directly address the requirements of such an application.In the RBAC model,the user is assigned a subset of roles when the user begins a session.This subset of roles are then used to access resources.During a session,although roles can be activated or deactivated based on constraints such as role con-flict or prerequisite roles,the user’s access privilege is not changed based on context information.Recently,Michael J. Covington et al.,have proposed the GRBAC model[11]that used context to provide access control for Aware Home ap-plications.However,the definition of environment role is not feasible for pervasive applications as described in the previous section.4.Dynamic role based access control modelDynamic Role Based Access Control model(DRBAC)ad-dresses the dynamic access control requirement of applica-tions in pervasive environments.It extends the traditional Role Base Access Control(RBAC)model to use dynamic context information while making access control decision.Specifi-cally,DRBAC addresses two key requirements motivated by the application in Section3:(1)A user’s access privileges must change when the user’s context changes.(2)A resource must adjust its access permission when its system informa-tion(e.g.,network bandwidth,CPU usage,memory usage) changes.In this section,wefirst formally define DRBAC and then describe its operation.4.1.DRBAC DefinitionThe DRBAC definition is based on the RBAC formalism pre-sented in[8].DRBAC has the following components:r USERS.A user is an entity whose access is being ERS represents a set of users.r ROLES.A role is a job function within the context of an organization with some associated semantics regarding the authority and responsibility conferred on the user assigned to the role.ROLES represents a set of roles.r PERMS.A permission is an approval to access one or more RBAC protected resources.PERMS represents a set of permissions.r ENVS.ENVS represent the set of context information in the system.We use an authorized“Context Agent”to collect context information in our system.r SESSIONS.A session is a set of interactions between sub-jects and objects.A user is assigned a set of roles during each session.The active role will be changed dynamically among the assigned roles for each interaction.SESSIONS represents a set of sessions.r UA.UA is the mapping that assigns a role to a user.In the session,each user is assigned a set of roles,the context information is used to decide which role is active.The user will access the resource with the active role.r PA.PA is the mapping that assign permissions to a role.Every role that has privilege to access the resource is as-signed a set of permissions,and the context information is used to decide which permission is active for that role.The model is illustrated infigure2.In the approach,a Central Authority(CA)maintains the overall role hierarchy. When the user logs on the system,based on the user’s capa-bility,a subset of the role hierarchy is assigned to the user for each session.Then the CA sets up an agent for that user and delegates the user’s right to that agent.The agent will monitor the environment status of the user and dynamically change the active role of the user.Every resource maintains a set of permission hierarchies for each potential role that will access the resource.The resource maintains its environment and dynamically adjusts the permissions for each role.We summarize the above discussions below:DRBAC Definition:–USERS,ROLES,PERMS,ENVS and SESSIONS(users, roles,permissions,environments and sessions,respec-tively).Figure2.Dynamic access control model.22ZHANG AND PARASHAR –ACT RO L E and ACT P E RM I SSI O N(active roleand active permission respectively).–UA⊆USERS×ROLES,a many-to-many mapping user-to-role assignment relation.–PA⊆PERMS×ROLES,a many-to-many mappingpermission-to-role assignment relation.–Assigned roles(u:USERS,e:ENVS)→2ROLES,the map-ping of user u onto a set of roles.–Assigned permissions(r:ROLES,e:ENVS)→2PERMS,themapping of role r onto a set of permissions.–User sessions(u:USERS)→2SESSIONS,the mapping ofuser u onto a set of sessions.–Session roles(s:SESSIONS)→2ROLESS,the mapping ofsession s onto a set of roles.Formally:session roles(s i)⊆{r∈ROLES|(session roles(s i),r)∈UA}–RH⊆ROLES×ROLES is a partial order on ROLES calledthe inheritance relation,written as≥,where r1≥r2onlyif all PERMS of r2are also PERMS of r1,and all users ofr1are also users of r2.–PH⊆PERMS×PERMS is a partial order on PERMScalled the inheritance relation,written as≥,where p1≥p2only if all permissions of p2are also permissions of p1,and all roles of p1are also roles of p2.4.2.DRBAC explainedIn DRBAC,each user is assigned a role subset from the en-tire role set.Similarly,each resource will assign a permissionsubset from the entire permission set to each role which has aprivilege to access the resource.Figure3illustrates the rela-tionship between the role hierarchy maintained at the CentralAuthority(CA)and the role hierarchy assigned to a particularuser.It can be seen that the role hierarchy a user is a subset ofthe overall role hierarchy.State machines maintain the role subset for each user andthe permission subset for each role.A state machine consistsof state variables,which encode its state,and events,whichtransform its state.In DRBAC,there is a Role State Machinefor each user,and a Permission State Machine for each role.The role and permission are used as state variables respec-tively.The Context Agent collects context information andgenerates pre-defined events to trigger transitions in thestateFigure3.Role hierarchy statemachine.Figure4.Permission hierarchy state machine.machines.A permission state machine is illustrated infig-ure4.A null permission implies no permission.A transition isdefined as T(Initial State,Destination State).So T(P1,P2)represents the transition from P1to P2and T(P2,P1)rep-resents the transition from P2to P1.The Role State Machineis similar to the Permission State Machine.4.3.DRBAC operationThe operation of DRBAC is illustrated using the example pre-sented in Section3.In this example,when Professor B logson the system in her office with a PDA,the central authorityassigns her a subset of roles,for example,Professor,Lec-turer and Faculty,based on her credentials.Then the centralauthority also sets up an access control agent on her PDA,which maintains the role state machine.Events issued by thecontext agent will trigger transitions between the roles in therole state machine.Now,consider a security policy that de-fines B’s active role as Professor when she is in the office(seefigure5,where the dashed circle is the active role),and de-fines the transition as:Change role from Professor to Facultywhen professor B leaves her office.When professor B accesses the resource in her office,theactive role Professor is used.The resource maintains the per-mission state machines as shown infigure 6.Thefigureshows that each of the roles,Professor,Faculty and Lecturer,have their own permission state machines.The dashed circlerepresents the current active permission for each role.Thenull means the role does not have permission to access theresource.Similar to the role state machine,the context agentat the resource will trigger transitions in the permission statemachine.In this example,we assume that the activepermis-Figure5.Role hierarchy for the smart building.SCALABLE,ENVIRONMENT SENSITIVE ACCESS MANAGEMENT ENGINE23Figure6.Permission hierarchy for the resource.sion of the role professor is P1while the system load of the resource is low.P1means both read and write privilege.The security policy for the resource may define a permission tran-sition for role professor as:Transit permission from P1to P2 when the system load is high.The permission P2means only read privilege.Based on the situations defined above,we can describe some scenarios to illustrate dynamic access control.r When professor B moves out of her office,the context agent will send an event to the access control agent on her PDA.This event will trigger a transition in the role state machine,changing her active role to Faculty.As a result, professor B will not be able to write to resource once she leaves her office as role Faculty only has the permission P2or null.r When professor B accesses the resource in her office,her active role is professor,which has both read and write privilege on the resource as long as the system load of the resource is low.If the system load becomes critically high,the resource permission state machine will change the active permission for professor B’s role professor to P2and she will lose the privilege to write the resource.From the scenarios described above,we see that DRBAC can enhance the security of the pervasive applications.The DRBAC mechanism implemented in this application guaran-tees that professor B’s privilege to access the resource will be changed dynamically when the context ing context information to change the user’s privileges prevents resources from being incorrectly used.5.SESAME/DRBAC prototype implementationA prototype of SESAME and the DRBAC model has been implemented as part of the Discover[2,18]computational collaboratory.Discover is a Grid-based computational col-laboratory that enables geographically distributed scientists and engineers to collaboratively access,monitor,and control distributed applications,services,resources and data on the Grid using pervasive portal.Key components of the Discover collaboratory include:r Discover Collaborative Portals[18]that provide users with pervasive and collaborative access to Grid applica-tions,services and ing these portals,usersFigure7.Dynamic access control in discover.can discover and allocate resources,configure and launch applications and services,and monitor,interact with,and steer their execution.r Discover Middleware Substrate[2,12]that enables global collaborative access to multiple,geographically dis-tributed instances of the Discover computational collab-oratory,and provides interoperability between Discover and external Grid services such as those provided by Globus[15].r DIOS Interactive Object Framework(DIOS)[13]that en-ables the runtime monitoring,interaction and computa-tional steering of Grid applications and services.DIOS enables application objects to be enhanced with sensors and actuators so that they can be interrogated and con-trolled.An overview of the integration of SESAME and DR-BAC with Discover is presented infigure7.SESAME ensures the users can access,monitor and steer Grid re-sources/applications/services only if they have appropriate privileges and capabilities.As Discover portals are perva-sive and the Grid environment is dynamic,this requires dy-namic context aware access management.Note that authen-tication services are provided by GSI[6]in our prototype implementation.In our implementation,users entering the Discover collaboratory using the portal are assigned a set of roles when they log in.A Role State Machine is then locally set up for each user,which dynamically adjusts the active role based on events from the local context agent.Similarly,the Permission State Machines are set up at the application(or ser-vice/resource)for each role that will access it.The Permission State Machines similarly adjust the active permissions based on events from the local context agent.The context agents are authorized by the central authority using GSI delegation mechanisms.The access control policy is stored in the policy repository,which is maintained by an Authentication&Au-thorization Service within Discover Middleware Substrate. Polices are specified in XML and define role/permission assignments and transitions as illustrated infigure8.24ZHANG ANDPARASHARFigure8.Sample RoleTransition policy in XML. Policies defined for our implementation include UserPolicy, RoleHierarchyPolicy,RoleAssignmentPolicy,Permission-AssignmentPolicy,EventPolicy,RoleTransitionPolicy and PermissionTransitionPolicy.In our prototype implementation,we assume that a secu-rity administrator will guarantee the correctness of a policy for a object or subject—i.e.SESAME sets up the Role State Machines and Permission State Machines without considering checking them for errors or conflicts.There are no inherent constraints on the number of roles and permissions,or on the relationships betweens the roles or permissions.To illus-trate our implementation,consider a simple example with a single user with three roles and a Grid resource with three permissions,as shown in Table1and2respectively.The role and permission hierarchies for this example are shown in figure9.We consider two types of context information in our im-plementation:(1)Object context such as a user’s location, time,local resource state and link state,and(2)Subject con-text,such as the current load,availability,connectivity for a resource.Context agents build on existing Grid middleware services.For example object context can be collected using the Context Toolkit[1]and subject context can be obtained using NWS[17].Table1Permission assignments for the example.Role Permissions Super user P1,P2,P3 Basic user P2,P3 Guest P3Table2Permission definition for the example.Permission PrivilegesP1Steer Object,View Object,Basic P2View Object,BasicP3BasicFigure9.Role and permission hierarchies for the example.5.1.SESAME/DRBAC operationThe operation of the prototype is illustrated using a set of simple scenarios.These scenarios,although somewhat con-trived,demonstrate the effectiveness and utility of the DRBAC model for Grid applications.For each of these scenarios,con-sider a user(say N)equipped with a mobile devices such as a PDA,and involved in collaboration scientific investigation using Discover.Assume that the user’s environment is part of the pervasive Grid environment with appropriate middleware services.Assume that user N logs into the system using her PDA. Based on her credentials,the Authentication&Authorization service assigns her a set of roles.The Authority Service also sets up an access control agent on her PDA,which main-tains the role state machine.A DRBAC policy defined to select an appropriate role based on the level of security of her wireless connection,i.e.her active role is Super User while the network is secure(e.g.in her laboratory or of-fice)and is Basic User if it is insecure.The correspond-ing EventPolicy and RoleTransitionPolicy may be defined as follow:–EventPolicy—Generate event insecure when N’s link has no encryption.–RoleTransitionPolicy—Transit role from Super User to Basic User when event insecure is generated.A corresponding permission state machine is maintained on the application side as shown infigure10.As seen in thefigure each role has its own permission state machine.The dashed circle represents the current active permission for each role.A DRBAC policy is defined so that the active permission of the role Super User is P1while load is low and P2when the system load increases above some threshold,as there is a possibility that the application may get corrupted.The cor-responding EventPolicy and PermissionTransitionPolicy may be defined as follow:–EventPolicy—Generate event highload when load in-creases above Threshold.–PermissionTransitionPolicy—Transit permission from P1 to P2when event highload is generated.。

ʌ文章编号ɔ1006-6233(2024)04-0609-05血清白介素-6降钙素原及C反应蛋白水平与新生儿败血症预后的关系许爱华,㊀顾㊀涛,㊀李㊀云,㊀方㊀飞,㊀王㊀静(安徽省滁州市第一人民医院新生儿科,㊀安徽㊀滁州㊀239000)ʌ摘㊀要ɔ目的:分析白介素-6(Interleukin,IL-6)㊁降钙素原(Procalcitonim,PCT)及C反应蛋白(C -Reactive protein,CRP)与新生儿败血症预后的关系㊂方法:选取2020年8月至2023年3月我院收治的新生儿败血症患儿86例为研究对象㊂分析治愈/好转组与死亡组的一般资料,对比两组患儿不同时期血清IL-6㊁PCT㊁CRP水平,分析影响新生儿败血症患儿预后的相关因素㊂结果:86例新生儿败血症患儿中,治愈/好转组有77例患儿,死亡组有9例患儿(死亡组患儿在12h内死亡4例,2d死亡2例,3d 死亡2例,5d死亡1例)㊂在发病12h㊁12~36h内以及7d内,死亡组IL-6>7pg/mL比例㊁PCT>0.5ng/ mL比例㊁CRP>10mg/mL比例均高于治愈/好转组,差异有统计学意义(P<0.05);两组性别㊁是否胎膜早破㊁是否为早产儿㊁有无黄疸㊁以及分娩方式等指标比较,差异无统计学意义(P>0.05);两组胎龄㊁出生时体重㊁0~6岁小儿神经心理发育检查表比较,差异有统计学意义(P<0.05);经过多因素Logistic回归分析显示,0~6岁小儿神经心理发育检查表㊁IL-6㊁PCT㊁CRP是影响新生儿败血症预后的独立危险因素(P<0.001)㊂结论:血清IL-6㊁PCT㊁CRP水平是影响新生儿败血症患儿预后的相关因素,监测血清IL-6㊁PCT㊁CRP水平,或可为临床调整新生儿败血症治疗策略提供可靠参考资料㊂ʌ关键词ɔ㊀白介素-6;㊀降钙素原;㊀C反应蛋白;㊀新生儿败血症;㊀预㊀后ʌ文献标识码ɔ㊀A㊀㊀㊀㊀㊀ʌdoiɔ10.3969/j.issn.1006-6233.2024.04.015Relationship between Serum IL-6PCT and CRP Levelsand Prognosis of Neonatal SepsisXU Aihua,GU Tao,LI Yun,et al(The First People's Hospital of Chuzhou City,Anhui Chuzhou239000,China)ʌAbstractɔObjective:To investigate the relationship between serum interleukin-6(IL-6),procalcito-nin(PCT),and C-reactive protein(CRP)levels and the prognosis of neonatal sepsis.Methods:A total of 86neonates with sepsis admitted to our hospital from August2020to March2023were enrolled as the study subjects.The general data of the cured/improved group and the death group were analyzed.The serum IL-6, PCT,and CRP levels of the neonates in the two groups at different time points were compared,and the factors affecting the prognosis of neonates with sepsis were analyzed.Results:Among the86neonates with sepsis, there were77neonates in the cured/improved group and9neonates in the death group(4neonates died within 12hours,2died within2days,2died within3days,and1died within5days).The percentages of IL-6> 7pg/mL,PCT>0.5ng/mL,and CRP>10mg/mL in the death group were higher than those in the cured/ improved group at12hours,12-36hours,and7days after onset(P<0.05).There were no statistically sig-nificant differences in gender,premature rupture of membranes,preterm birth,jaundice,and delivery method between the two groups(P>0.05).The gestational age,birth weight,and Ages&Stages Questionnaires (ASQ)at0-6years old were significantly different between the two groups(P<0.05).Multivariate logistic regression analysis showed that ASQ at0-6years old,IL-6,PCT,and CRP were independent risk factors for the prognosis of neonatal sepsis(P<0.001).Conclusion:Serum IL-6,PCT,and CRP levels are related factors affecting the prognosis of neonates with sepsis.Monitoring serum IL-6,PCT,and CRP levels may pro-vide reliable references for clinical adjustment of treatment strategies for neonatal sepsis.ʌ基金项目ɔ2021年度安徽省卫生健康委科研项目,(编号:AHWJ2021b005)㊃906㊃ʌKey wordsɔ㊀IL-6;㊀PCT;㊀CRP;㊀Neonatal sepsis;㊀Prognosis㊀㊀败血症是指细菌在新生儿期侵入其血液中,同时可通过血液循环通路及病毒复制方式造成新生儿出现全身性感染,其具有病程多变性㊁病情隐匿㊁发病快且急以及病死率高等特征[1]㊂在临床研究中发现,败血病多发生于新生儿,这是由于新生儿器官及免疫系统均未完全发育,这将严重威胁到新生儿的健康安全,甚至死亡[2]㊂经过大量研究发现,早期诊断新生儿败血症㊁及时评估该疾病的严重程度及预后,并对其进行干预,可有效降低患儿病死率[3]㊂因此,早期对新生儿败血症的诊断以及及时进行有效的治疗至关重要㊂相关研究指出,C反应蛋白(C-Reactive protein,CRP)在诊断新生儿败血症方面的特异性较高,但其灵敏度较低;白介素-6(Interleukin,IL-6)水平可在新生儿败血症早期迅速升高,对早期诊断新生儿败血症具有重要价值;降钙素原(Procalcitonim,PCT)水平则在新生儿败血症急性期显著升高,且不受其他因素影响,而当患儿病情得以好转后就会逐渐恢复至正常水平[4]㊂本文旨在分析IL-6㊁PCT及CRP与新生儿败血症预后的关系㊂1㊀资料与方法1.1㊀一般资料:选取2020年8月至2023年3月我院收治的新生儿败血症患儿86例为研究对象,其中男60例,女26例;胎龄36~41周,平均胎龄(38.62ʃ0.71)周;自然分娩47例,剖宫产39例;出生时体重2. 08~3.92kg,出生时平均体重(2.68ʃ0.62)kg㊂纳入标准:①观察组患儿均符合新生儿败血症的诊断标准(血培养或无菌体腔内培养出致病菌)[5];②临床资料完整;③均为单胎妊娠;④新生儿年龄均<28d㊂排除标准:①具有家族遗传性疾病者;②肝肾功能严重障碍者;③新生儿合并患有自身免疫性疾病者或先天性疾病者㊂1.2㊀方法:IL-6㊁PCT㊁CRP检测:抽取所有患儿外周空腹静脉血5mL,使用离心半径为5cm的血型血清学离心机HT12MM,离心(3000r/min,10min,8cm),分离血清㊂采用电化学发光法检测血清IL-6(试剂由罗氏(Roche)公司提供)㊁PCT(试剂由罗氏(Roche)公司提供),采用免疫比浊法检测CRP(试剂由深圳锦瑞生物科技有限公司提供)㊂严格按照说明书进行操作㊂临床转归情况:根据临床转归情况将所有患儿分为治愈/好转组与死亡组,转归观察终点为患者死亡或出院,好转指经过临床治疗后病情处于稳定状态,临床症状好转,感染得到有效控制㊂0~6岁小儿神经心理发育检查表:包括适应能力㊁精细运动㊁大运动㊁语言以及社交行为5个项目,发育商共90分,分数越高,预后情况越好㊂1.3㊀统计学方法:采用SPSS21.0统计软件进行统计分析,计量资料采用( xʃs)表示,两组间比较采用独立样本t检验;计数资料通过n(%)表示,两组间比较采用χ2检验;采用多因素Logistic回归分析影响新生儿败血症患儿预后的相关因素;以P<0.05为差异具有统计学意义㊂2㊀结㊀果2.1㊀预后情况:86例新生儿败血症患儿中,治愈/好转组有77例患儿,死亡组有9例患儿(死亡组患儿在12h内死亡4例,2d死亡2例,3d死亡2例,5d死亡1例)㊂2.2㊀对比两组患儿不同时期的血清IL-6㊁PCT㊁CRP 水平:在发病12h㊁12~36h内以及7d内,死亡组IL-6> 7pg/mL比例㊁PCT>0.5ng/mL比例㊁CRP>10mg/mL比例均高于治愈/好转组,差异有统计学意义(P<0.05)㊂见表1~3㊂表1㊀两组12h内血清IL-6PCT CRP比较n(%)组别例数IL-6>7pg/mL PCT>0.5ng/mL CRP>10mg/mL治愈/好转组7732(41.55)31(40.26)40(51.94)死亡组97(77.78)7(77.78)8(88.89)χ2 4.265 4.599 4.459 P0.0390.0320.035㊃016㊃表2㊀两组12~36h血清IL-6PCT CRP比较n(%)组别例数IL-6>7pg/mL PCT>0.5ng/mL CRP>10mg/mL治愈/好转组7724(31.17)26(33.77)42(54.55)死亡组94(80.00)4(80.00)5(100.00)χ2 4.978 4.326 3.965 P0.0260.0370.046表3㊀两组7d内血清IL-6PCT CRP比较n(%)组别例数IL-6>7pg/mL PCT>0.5ng/mL CRP>10mg/mL 治愈/好转组7741(53.25)33(42.86)42(54.55)死亡组98(88.89)7(77.78)8(88.89)χ2 4.176 3.949 3.905 P0.0410.0470.0482.3㊀治愈/好转组与死亡组临床资料对比:两组性别㊁是否胎膜早破㊁是否为早产儿㊁有无黄疸㊁以及分娩方式等指标比较,差异无统计学意义(P>0.05);两组胎龄㊁出生时体重㊁0~6岁小儿神经心理发育检查表比较,差异有统计学意义(P<0.05)㊂见表4㊂表4㊀治愈/好转组与死亡组的临床资料对比[n(%), xʃs]因素治愈/好转组(n=77)死亡组(n=9)χ2/t P 胎龄(周)37.54ʃ0.6736.79ʃ0.75 3.1400.002性别男53(68.83)7(77.78)0.3060.580女24(31.17)2(22.22)胎膜早破有8(10.39)2(22.22) 1.0980.295无69(89.61)7(77.78)早产儿是32(41.56)6(66.67) 2.1450.143否45(58.44)3(33.33)黄疸有35(45.45)6(66.67)0.5720.449无42(54.55)3(33.33)分娩方式自然分娩49(63.64)5(55.56)0.2250.635剖宫产28(36.36)4(44.44)出生时体重(g)2038.36ʃ755.342635.21ʃ864.92 2.2160.029 0~6岁小儿神经心理发育检查表得分(分)74.52ʃ4.3862.81ʃ3.327.747<0.001㊃116㊃2.4㊀影响新生儿败血症预后的相关因素:以新生儿败血症预后为因变量将差异具有统计学意义的数据,见表5,经过多因素Logistic回归分析显示,0~6岁小儿神经心理发育检查表得分㊁IL-6㊁PCT㊁CRP是影响新生儿败血症预后的独立危险因素(P<0.001),见表6㊂表5㊀变量赋值因素变量赋值X10~6岁小儿神经心理发育检查表得分实测值X2IL-60=ɤ7pg/mL;1=>7pg/mL X3PCT0=ɤ0.5ng/mL;1=>0.5ng/mL X4CRP0=ɤ10mg/mL;1=>10mg/mL表6㊀影响新生儿败血症预后的危险因素分析相关因素β标准误Waldχ2OR(95%CI)P 0~6岁小儿神经心理发育检查表得分0.3540.1279.670 1.424(1.110~1.827)<0.001 IL-6 1.024 1.0670.852 2.784(0.34~22.54)<0.001 PCT0.4250.0859.624 1.529(1.294~1.806)<0.001 CRP0.6720.307 5.137 1.958(1.072~3.574)<0.0013㊀讨㊀论新生儿败血症是一种严重的新生儿感染性疾病,一旦发生新生儿败血症,感染极易扩散,这会增加新生儿出现预后不良的概率㊂大量研究指出,新生儿败血症患儿的死亡率为30%~50%,早期诊断出新生儿败血症并给予其有效的治疗可提高其治愈率以及改善其预后[6]㊂实际上,新生儿败血症的早期症状不明显,若仅通过临床表现进行诊断,易出现漏诊与误诊㊂临床用于确诊新生儿败血症的标准为血培养,但其存在操作技术等不足之处,因此,需找寻其他有效的实验室指标辅助诊断新生儿败血症㊂IL-6是由B细胞与T细胞等合成的一种炎性因子,当机体出现创伤㊁感染以及应激反应等急性炎症反应时会迅速分泌IL-6,具有致炎作用㊂有报道指出,新生儿败血症患儿的机体内会出现炎症,刺激B㊁T㊁单核细胞等大量分泌IL-6,致使外周血中IL-6水平大幅度升高;当患儿出现临床症状的前2d,IL-6浓度显著升高,因此IL-6被认为是早期诊断新生儿败血症重要的指标之一[7]㊂PCT通常具有较强的稳定性,但其一旦被炎症反应刺激,肝组织内的细胞可通过炎性因子对PCT进行降解,从而血液中的PCT浓度显著升高[8]㊂以往有研究称,当全身感染出现3~4h时就可检测出PCT水平,且其在14h时达峰值,24h内其水平持续上升,可作为监测早期细菌感染的特异性指标[9]㊂鲁静[10]学者发现,当发生新生儿败血症时,细胞将会产生大量内毒素,同时会刺激巨噬细胞㊁单核细胞等释放大量PCT,但内毒素会使患儿的脏器造成损伤,因此内毒素分泌越多,PCT浓度则越高,患儿预后则越差㊂CRP则是当机体受到创伤或发生炎症反应时大量产生,CRP在介导炎症反应造成组织损伤的同时还可募集㊁诱导单核细胞㊁浆细胞以及中性粒细胞浸润,致使炎症反应的级联放大,可作为非特异性细菌感染指标[11]㊂申存存[12]学者发现,CRP水平在急性组织损伤以及炎症后的4~6h内迅速升高,36~50h可达峰值,其水平与感染的严重程度呈正相关㊂本次研究发现,在发病12h㊁12~36h内以及7d内,死亡组IL-6> 7pg/mL比例㊁PCT>0.5ng/mL比例㊁CRP>10mg/mL 比例均高于治愈/好转组,提示病情严重的患儿炎症反应更重,与申存存研究结果相似,后进一步经过Logis-tic多因素分析显示,0~6岁小儿神经心理发育检查表㊁IL-6㊁PCT㊁CRP是影响新生儿败血症预后的独立㊃216㊃危险因素(P<0.001),提示临床需重视新生儿败血症IL -6㊁PCT ㊁CRP 水平的监测㊂综上所述,血清IL -6㊁PCT ㊁CRP 水平是影响新生儿败血症患儿预后的相关因素,监测血清IL -6㊁PCT ㊁CRP 水平,或可为临床调整新生儿败血症治疗策略提供可靠参考资料㊂ʌ参考文献ɔ[1]㊀池秀芳,陈佳.新生儿败血症病原学及耐药性分析[J ].广东医学,2022,43(1):36-39.[2]㊀张江玲.个性化干预模式对新生儿败血症的影响[J ].中国妇幼保健,2023,38(6):1129-1132.[3]㊀庞玮,刘静,侍海棠.新生儿败血症核因子-κB 和中性粒细胞CD11b ㊁CD64表达及与病情严重程度的关系[J ].中华医院感染学杂志,2022,32(6):902-905.[4]㊀刘启星,王斌.IL -6㊁TNF -α和CRP 联合检测在新生儿败血症诊断中的临床意义[J ].检验医学与临床,2021,18(15):2272-2274.[5]㊀姜毅.新生儿败血症诊疗进展[J ].中国新生儿科杂志,2010,25(2):69-72.[6]㊀Deng Xiaoyao ,Tian Zhiliang.Research progress of erythro-cyte volume distribution width in neonatal sepsis [J ].Chi-nese Journal of Medical Education ,2022,45(3):285-288.[7]㊀郭景瑞,高奶荣,祝颖,等.新生儿败血症T 淋巴细胞亚群㊁PCT ㊁CRP ㊁Lac 及炎症因子的检测及其临床意义[J ].海南医学,2020,31(20):2620-2622.[8]㊀Liu Qian ,Liu Xue -Qin ,Yuan Li ,et al.Application of pe-ripheral blood T lymphocyte subsets and PCT in diagnosis and prognosis evaluation of neonatal sepsis [J ].Chinese Journal of nosocomiolog ,2021,31(12):1786-1790.[9]㊀潘晓浩,郝建石,黄建芳,等.降钙素原及血清淀粉样蛋白A 在诊断新生儿败血症中的临床应用价值[J ].中国卫生检验杂志,2022,32(12):1478-1481.[10]㊀鲁静.血清降钙素原在新生儿败血症病情和预后评估中的应用价值[J ].新乡医学院学报,2021,38(12):1171-1174.[11]㊀王晓蔚,何米兰,夏泳波,等.Hs -CRP ㊁CD64㊁sTREM -1水平联合检测在新生儿败血症诊断中的应用[J ].基因组学与应用生物学,2020,39(2):969-974.[12]㊀申存存,赵春慧,邱净净,等.降钙素原㊁C 反应蛋白及白细胞参数对新生儿败血症病情诊断的临床意义[J ].临床血液学杂志,2022,35(4):256-259.临床研究ʌ文章编号ɔ1006-6233(2024)04-0613-06急性脑梗死患者急诊介入溶栓治疗后早期神经功能恶化影响因素分析张㊀峰,㊀季㊀流,㊀葛春阳,㊀李海山(安徽省合肥市第二人民医院急诊科,㊀安徽㊀合肥㊀230011)ʌ摘㊀要ɔ目的:探讨急性脑梗死患者急诊介入溶栓治疗早期神经功能恶化(END )影响因素㊂方法:选择我院于2020年3月至2023年3月行急诊介入溶栓治疗的急性脑梗死患者105例,按照溶栓内24h 是否发生END ,分为END 组34例与非END 组71例㊂采用单因素分析影响END 的相关因素;多因素Logistic 回归分析影响END 独立危险因素㊂结果:经单因素分析计数资料显示,END 组和非END 组性别㊁年龄㊁BMI ㊁吸烟史㊁饮酒史㊁高血压史㊁糖尿病史㊁冠心病史和责任大血管分布差异无统计学意义(P >0.05);END 组和非END 组责任大血管狭窄程度比较差异具有统计学意义(P <0.05)㊂经单因素分析计量资料显示,END 组与非END 组入院时NIHSS 评分㊁溶栓时间㊁白细胞计数㊁中性粒细胞计数㊁Lp -PLA2水平和脂蛋白a 水平比较差异具有统计学意义(P <0.05);而END 组与非END 组发病至溶栓时间㊁D -二聚体和Hcy 水平比较差异无统计学意义(P >0.05)㊂多因素Logistic 回归分析的结果显示,责任大血管狭窄程度㊁入院时NIHSS 评分㊁溶栓时间㊁白细胞计数㊁中性粒细胞计数㊁Lp -PLA2和脂蛋白a 为影响END 独立危险因素㊂结论:急性脑梗死患者急诊介入溶栓治疗后END 发生率较高,且受多因素影响,其中责任大血管狭窄程度㊁入院时NIHSS 评分㊁溶栓时间㊁白细胞计数㊁中性粒细胞计数㊁Lp -㊃316㊃ʌ基金项目ɔ2020年度安徽省自然科学基金项目,(编号:2008085QH353)ʌ通讯作者ɔ李海山。

萨丕尔－沃尔夫假设主要内容美国人萨丕尔及其弟子沃尔夫提出的有关语言与思维关系的假设是这个领域里至今为止最具争议的理论。

沃尔夫首先提出，所有高层次的思维都倚赖于语言。

说得更明白一些，就是语言决定思维，这就是语言决定论这一强假设。

由于语言在很多方面都有不同，沃尔夫还认为，使用不同语言的人对世界的感受和体验也不同，也就是说与他们的语言背景有关，这就是语言相对论。

Linguistic relativity stems from a question about the relationship between language and thought, about whether one's language determines the way one thinks. This question has given birth to a wide array of research within a variety of different disciplines, especially anthropology, cognitive science, linguistics, and philosophy. Among the most popular and controversial theories in this area of scholarly work is the theory of linguistic relativity(also known as the Sapir–Whorf hypothesis). An often cited "strong version" of the claim, first given by Lenneberg in 1953 proposes that the structure of our language in some way determines the way we perceive the world. A weaker version of this claim posits that language structure influences the world view adopted by the speakers of a given language, but does not determine it.[1]由萨丕尔－沃尔夫假设的这种强假设可以得出这样的结论：根本没有真正的翻译，学习者也不可能学会另一种文化区的语言，除非他抛弃了他自己的思维模式，并习得说目的语的本族语者的思维模式。

欧洲面临的另一个危机经济衰退使欧洲短暂的生育高潮骤然停止Jun30th2012|VIENNA|from the print edition欧洲所面临的危机其实质远比看起来要糟糕。

好像是混乱的金融市场与衰退的经济给这个大陆带来的负担还不够重似的，欧洲生育率在走了长达十年（几乎被忽视）的上坡路后又骤然停止了。

到目前为止，今年已提交数据的15个国家中有11个国家2011年的人口出生率下降（生育率指一个妇女一生中的平均生育子女数）。

生育率跌幅最大国家中有一些就是受欧元危机打击最严重的国家。

西班牙的生育率从2008年的1.46下降到了2011年的1.38。

拉脱维亚的生育率则从1.44降到了1.20以下。

维也纳人口统计学协会的托马斯•索博特卡指出，这些国家前十年的生育率上升被三年的下降抵消。

一些北欧国家虽然并未出现激增的失业率，也未大幅削减政府开支，但生育率跌幅仍然很大。

2010年至2011年间，挪威的生育率从1.95下降到了1.88，丹麦则从1.88下降到了1.76。

但是，无论是像英国那样有着高生育率的国家还是如匈牙利一般生育率低下的国家，这些国家的生育率所呈现的趋势如出一辙：受经济危机影响，生育率在上升了十年之后，于2008年前后停止上升，并从2011年起下滑（见图1）。

从市场角度看，三年是一段很长的时间；从人口统计学角度看，三年不过是一眨眼的功夫。

一件事的发生对人们的影响和造成的改变至少需要九个月的时间（怀胎期）才能体现在出生率上。

在人口统计上也是如此，影响会滞后一年左右才体现出来。

在经济衰退开始之后如此短暂的时间里能看到出生率的变化趋势是很惊人的。

但是，尽管经济萧条与家庭组成存在联系，但这种联系的本质存在争议。

亚当•斯密认为经济的不确定性对生育率的提升有着消极的影响。

但也有人认为经济衰退会降低生育孩子的机会成本，鼓励妇女在失业期间生育本来就打算要的孩子，从而提高出生率。

欧洲最近的经历印证了亚当•斯密的观点。

A high-performance ground-based prototype of horn-typesequential vegetable production facility for life support system in spaceYuming Fu a ,1,Hui Liu a ,1,Lingzhi Shao a ,1,Minjuan Wang a ,Yu A.Berkovich b ,A.N.Erokhin b ,Hong Liu a ,⇑aLaboratory of Environmental Biology and Life Support Technology,School of Biologic a l Science and Medical Engineerin g ,Beihang University,Beijing 100191,ChinabState Scientific Center of the Russian Federation,Institute for Biomedica l Problems,Moscow 123007,RussiaReceived 28 November 2012;received in revised form 4February 2013;accepted 14 March 2013AbstractVegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight.Here we developed a ground-based prototype of horn-type sequential vegetable production facility,named Horn-type Producer (HTP),which was capable of simulating the microgravity effect and the continuous cultivation of leaf–vegetables on root modules.The growth chamber of the facility had a volume of 0.12 m 3,characterized by a three-stage space expansion with plant growth.The planting surface of 0.154 m 2was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate.Root modules were fastened to a central porous tube supplying water,and moved forward with plant growth.The total illuminated crop area of 0.567 m 2was provided by a combination of red and white light emitting diodes on the internal surfaces.In tests with a 24-h photoperiod,the productivity of the HTP at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week.Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent.Furthermore,the efficiency of the HTP,based on the Q-criterion,was 7Â10À4g 2m À3J À1.These results show that the HTP exhibited high productivity,stable quality,and good efficiency in the process of planting lettuce,indicative of an interesting design for space vegetable production.Ó2013COSPAR.Published by Elsevier Ltd.All rights reserved.Keywords:Ground-ba s ed prototy p e;Horn-type ;Vegetable sequential production;Life support system1.Intr o ductionVegetabl e cultivat i on plays an essent i al role for the life suppo r t system.In the control l ed ecologi c al life supp o rt system (CE LSS)requ i red by long-du r ation future habita -tion of space involving great dist a nces from Ear t h and/or large crew sizes (e.g.,lun a r outpost ,Mars base),vegeta b les as a part of autotr o phic creat u res can regen e rate oxygen and foo d ,whi l e removin g carbon dioxide and purifying waste wat e r for human life (Mitc h ell,1994;Tong et al.,2011a;Wh e eler,2006 ).In the physica l /chemi c al life sup -port syst e m of the inter n ationa l space station (ISS)an d on Marti a n spacecr a ft,vegeta b les are mainly used to enhance the diet divers i ty of crew and sati s fy needs with fresh vita m ins and rough dieta r y fibers (Berk o vich et al.,2009;Kliss et al.,2000 ).Meanw h ile,feedi n g vegeta b les of antiox i dant-ri c h ha s been prop o sed a potenti a l coun t er- measur e of mit i gating deleterious effects produ c ed by space radiation on crew (Lev i ne and Pare,2009;Smit h an d Zwart,2008 ).Except for diet signi ficance,cultivation veg- etable was also regarde d as an attr a ctive alte r native to impro v e livin g environm e nt conditio n s onboa r d and pro- vide a psychologi c al be n efit for crew (Kim et al.,2004a ).The idea of onboa r d cultivat i on of salad- t ype ve g etables for crew consumpt i on was prop o sed as a first step of CE LSS applie d to space enc l osed environm e nt (Kliss0273-1177 /$36.00 Ó2013 COSPAR.Published by Elsevier Ltd.All rights reserved./10.10 16/j.asr.2013 .03.020⇑Corresp o nding author.Tel.:+86 10 8233983 7;fax:+86 10 8233928 3.E-mail address:LH64@bu a (H.Liu).1These authors contributed equally to this work.www.elsevie r .com/loca t e/asrAdvance s in Space Research xxx (2013)xxx–xxxet al.,2000;Wheeler ,2009 ).Over the past few decad e s,many resear c hers have pursued developm e nt of salad-type vegeta b le produ c tion facility onboa r d (Ber k ovich et al.,2004b;Morrow et al.,2005 ).A small salad machi n e named Lada ,was success f ully install e d in IS S to pro v ide an oc c a- sional vegetab l e food and a source of recrea t ion (Sychev et al.,2007 ).How e ver,the vegeta b le produ c tion facility providi n g an d maint a ining a large con t inuous fres h pro- duce to meet the daily vegeta b le ne e ds of multi-crew ,has not been establis h ed due to resourc e limitation.In the developm e nt of vegeta b le prod u ction facility in space,increa s ing prod u ction efficiency per unit of consumabl e resourc e s (power,volume ,crew labor,etc.)is one of the most critical issues.The purpo s e of this work was to de s ign a new protot y pe of vegeta b le producti o n facility with enhan c ed efficiency,and to esti m ate its vegeta b le product quality unde r long-t e rm operati o n.Here,we de v eloped a horn-t y pe sequ e ntial vegeta b le produ c tion facility with high-e fficiency,named Ho r n-type Prod u cer (HTP).The faci l ity shows promi s e for the devel- opment of ve g etable cultivat i on facility simila r to the HTP as an effective option for providi n g co n tinuous vege t able produ c t to futur e space mis s ion.2.Cons t ruction and operat i on of the HT P 2.1.Configurations of the HTPThe HT P compri s es four major compon e nts:(1)growth chamber,(2)root modules ,(3)light subsystem,and (4)Berkovich et al.,2004a ).Therefor e ,the plantgrow t h cham- ber and planti n g surface were designe d with tw o co a xial cylinders in the HTP.The diame t er,lengt h and volume of plant growth chamber wer e 61 cm,42 cm and 0.12 m 3,respectivel y .The cylin d rical plan t ing surface (0.154m 2)was comp r ised of six identi c al ring-shaped root modules fastened to a centra l por o us tub e supp l ying water.The planting cyli n der with centra l porous tube had outer diam- eter of 15 cm,an d could rotate aroun d a horizont a l axis apart from grow t h ch a mber.The ring-shap e d root module was mad e of tw o identical semicirc u lar parts,with each con t aining an upper lid an d a bottom br a cket of stai n less steel (Fig.2).A gap in width of Fig.1.General view of the HTP:(A)closed,(B)opened.Table 1Techni c al specifications for the HTP.Paramete r s ValueDiamet e r of the growth chamber (cm)61 Length of the growth chamber (cm)42 Planting area (m 2)0.154 Total illuminated crop area (m 2)0.567 Volum e of growth chamber (m 3)0.12 Numbe r of root module 6Characte r istics of light source Red LED (660nm),White LED (2700K)Numbe r of LED (pcs)Red:872 White:694 Average PAR(l mol m À2s À1)350 ±50 Numbe r of fans8Total power demand (KW)0.308 Power demand without rotation (KW)0.2832Y.Fu et al./Advances in Space Research xxx (2013)xxx–xxxities of delivering nut r ients,water and ox y gen into plan t roots under micro g ravity during long-term plant growth (E rokh i n et al.,2006 ).The lighting subsyst e m for growing plan t s ne e ds to be lightw e ight,reliable and durable.Light- e mittin g diodes (LE Ds)meet these charact e ristic s.The combination of red (600–700nm)and blue (400–500nm )LEDs was proven to be an effective light resourc e for many crops in con- trolled en v ironm e nt (Goins et al.,1997;Kim et al., 2004b;Yori o et al.,2001 ).How e ver,other spectr a l bands such as green,far- r ed and UV lights ha v e a positive influ- ence on plant biomas s by triggeri n g physiol o gical reaction s to control their grow t h and developm e nt (Br i ggs et al., 2001;Br i ggs and Olney,2001 ;Kim et al.,2004a ).White LE D has a co n tinuous spec t rum,includi n g all spectra l band s ne e ded in the grow t h and developm e nt of plant. Hence,we ch o se a combinat i on of red (660nm)and whi t e (2700K)LE D s as light source in the HTP.Consideri n g light atte n uation from the light sou r ce to the crop canop y, the light i ng subsyst e m set up on the inter n al surfa c e of grow t h chamber was designe d to form a hor n with three stage s co m posi n g of cone–cylinder,ba s ed on the S-shaped grow t h model of cylind e r–truncated crops (Fig.3A).In the first stage ,10 rectangu l ar pan e ls with 200 red 2and 150 white LE Ds were mounted to form a smal l cylind e r with diame t er of 32 cm and height of 13.5 cm.The third stage was a big cyli n der with 60 cm diame t er and 7cm height , which was made up of 10 recta n gular panels with 192 red and 144 white LE D s.A truncated con e with height of 20 cm consisted of ten trapez o id pa n els with 480 red and 400 white LE D s was between the first an d third stage s. The total illumina t ed crop area in the lighting subsystem was 0.567 m2.The corres p ondin g average light intensit i es at a dist a nce of 5cm below the LED lights from the first stage to the third stage wer e200,350 and 500 l mol mÀ2-sÀ1,respect i vely (Fig 3B).This sett i ng of light intens i ties was suited to vegeta b le growth of the seed l ing period,rapid growth period and harvested period for saving energy and impro v ing lettuce qua l ity (Aver c heva et al.,2009;Mccall and Willumse n,19 99).The water supp l y sub s ystem of the HTP employ e d a porous tube water and nutri e nt deliv e ry with the E bb and Flow stra t egy descri b ed in previous studies (Ber k ovich et al.,2005;Berk o vich et al.,20 02 ),whi c h was proven to be a good way to maint a in reli a ble de l ivery of wat e r an d nutrien t s to the plant root zone in space.The centra l por- ous titanic tube coati n g a water-sw e lling material was embedded in stain l ess steel tube with gaps (Fig.4).The contact betw e en wat e r-swelli n g mate r ials of the cen t ral porous tube and the roo t modu l es made success f ul delivery of wat e r and nutri e nt between them.For grou n d-based vegeta b le planti n g tests,the water and nutri e nt were deliv- ered to root modules unde r a negative pressur e of À0.5–À0.2 kPa insi d e the poro u s tube.In ad d ition to subsyst e ms men t ioned above,the HT P had an elect r ic motor drivi n g rotation of the stai n less steel tube through a chain wheel to coun t eract gravi t ational effects on the vegeta b les grown on the roo t mod u les.Eight fans pro v ided air venti l ation for the grow t h chamber (Fig.1).In ad d ition,the faci l ity requ i red 0.3 kW power to maint a in HTP ope r ation .2.2.Operati o n of the HTPThe step-1 root module with seed s was assem b led on ini- tial posit i on of central stai n less steel tube under the first stage of light subsyst e m.After a time inter v al of 5–7da y s, the vegeta b le seeds deve l oped into seedli n gs,the root mod- ule wi t h seedli n gs was moved forward to the next step along the central stainles s steel tube.At this time,theRoot module of the HTP:(A)upper lid of the semicircular part;(B)bottom bracket of the semicircu l ar part;(C)a assembly of two semicircular parts;(D)a root module with harvestable lettuce.2For interpretatio n of color in Fig.3,the reader is referred to the webversion of this article.step-2 root mod u le with seeds was assem b led on the initial posit i on.After 5repetitio n s of the planting and steppi n g (i.e.,25–35days),the step- 1root mod u le with harvestable biomas s arrived at the end posit i on of centra l stain l ess steel tube unde r the third stage of light subsyst e m as shown in Fig.3A.Then,the plants grow n on step-1 root module har- veste d after furth e r growth of 5–7days and the vacan t roo t module was replanted using new BION A-V3 artificial soil . To simulat e micr o gravity effect and get morpholog i cal l y normal plants in the grow t h chamber,the root modu l es assem b led on stainles s steel tube wer e rotat e d with rotation veloci t y of 12 rotations per hour.In this way,the HT P was able to continuou s ly pro d uce harvest a ble vegeta b le crops with each step at 5–7day interv a ls.3.Planti n g exper i m ent s3.1.Mater i als an d met h ods3.1.1.Let t uce cultivat i on,harves t and pretreatm e ntLettuce (Lactuca sativa L.va r.dasusheng)was selected as the plant mate r ial in this study.The plant de n sity of let- tuce was eight plan t s pe r module.The tim e interval of plantin g every roo t module was 7days,resul t ing in a42- day grow t h durati o n of lettuce in the HT P.The HTP was con t inuous l y ope r ated for 105 da y s,an d thegrown on ten roo t mo d ules were ha r vested at 7-day inter- val one another.Environme n tal parame t ers for the specie included 24 h lighting per day,air tempe r ature 23 ±relative humidi t y from 30 to 35%,and ambien ($350 ppm).The 1/2 con c entra t ion Hoaglan d(pH6.5)was used .At harvest of every root modufresh weigh t of edible biomas s was measur e d,divided into two pa r ts for different ana l yses.Onewas dried at 105 °C for 1h and at 60 °C for 8h,anused for mois t ure content and crude fiber analys i s.half was imm e diately lyophil i zed with liqui d nitr ostored at À80°C for nutri e nt content (vitamins and miner- als)and nitrate level detection .As a compari s on,the same lettuce cultivar purch a sed from a local grocery store was also analyze d.3.1.2.Assessm e nt of lettuce quali t y(1)Crude fiber determinat i onNeutr a l deterg e nt reagen t method was used to analyze crude fiber content of lettu c es.Briefly,1g dry sampl e was added into 100 ml of cold laurel sodium sulfate,mixe d at pH 7.0.Then 2ml of decahyd r onaphthal e ne and 0.5 g of sodium sulfite wer e ad d ed.The hom o genate was ke p t at 110°C for 60 min,filtered and was h ed with hot water and then acetone.The sample was finally dried on afilter paper at 100 °C for 80 min (Guevar a and Yahia,2003 ).(1)Vi t amin and mineral content de t erminat i onAscor b ic acid (vitamin C)co n tent was determ i ned using 2,6-dichlor o indop h enol dy e(AOAC,2000 ).The oth e r vita- mins such as b-carotene (provitamin A),thiamin (vitamin B1),riboflavin(vitamin B2),niacin (vitamin B3),panto- thenic acid (vitamin B5)and folat e(B9)were investiga t edLight subsystem of the HTP:(A)three-stag e design of light subsystem for the HTP;(B)3D mapping of the HTP photosynt h etic photon flux Measurem e nts recorded at a distance of 5cm below the LED lights.Fig.4.Structure of central tube for water supply of the HTP.by Chi n ese standar d methods as de s cribed in a previou s study (Tong et al.,2011b ).The co n tents of minerals involv -ing potass i um,sodium ,phosph o rus,calci u m,magn e sium copp e r,iron,magnes i um and zinc wer e determined acco r d- ing to AO A C method (AO A C,2000 )using an atomic absorpt i on spectro p hotomet e r (1100B,Perkin- E lmer ,Germ a ny).(1)Nitrat e level determ i nationLettuce sampl e s were freeze-dri e d and pulveriz e d with a mort a r.0.2 g of the pulverized mate r ial,which could passed throu g h a 60-m e sh sieve ,was trans m itted to a ce n - trifugal tube with 10 ml of distilled wat e r.The nitrate was extra c ted afte r incu b ation of the material for 30 min at 100°C.The extra c tion supernat a nt in the centri f ugal tube was filtered using a 0.45-mm membr a ne filter.The nitrate level analys i s was carri e d out using an Ion Chrom a togra p h (ICS 90,DIO N E X,US).3.2.Statisti c al analys i sSPSS 20.0 soft w are for Window s was used for stat i stical analys i s.Aver a ge values with standar d deviation of three repeat s were an a lyzed in this study.One- w ay analys i s of varia n ce (ANOVA)followe d by a Duncan ’s test was pe r - form e d to analyze the significant difference (p <0.05)in the measu r able parame t ers of lett u ces.3.3.Result s and analyse s3.3.1.Lettuce product i on grown in the HTP In gen e ral,the lettuces grow n on the root mod u les were morpho l ogically nor m al as shown in Fig.5.The average edible fresh biomas s harvest e d on a root module was 253.4 g,wi t h a range of 202.2–316.5 g (Tabl e S1 ).The cor- respond i ng average edible fres h biomas s per plant was 31.7 g,an d moisture con t ent was between 92%There was no significant difference betwe e n lettuce grow n on root modules andthat from the grocery store (Fig.6).The fact showe configuration s of the HT P wer e of normal plant gro w th.Furtherm o re,the HT P the average salad produ c tivity of 36.2 g maxi m um pro d uctivity of 45.2 g per day at 0.3 consu m ption.Previous studies showe d the maxi produ c tivity of fresh biomas s during co n tinuous in the hermetical l y sealed chamber (Wh e eler et in the Space plant grow t h ch a mber “vitacycle ”(et al.,2004b )was about 150–160g per da y ously,the maxi m al salad pro d appro x imatel y the lower bound of this level.3.3.2.Crude fiber,vitami n ,and mineral co n lettuces grown in the HTP Green leaf y vegeta b vitamins ,miner a ls and fibres (Alfaw a z,2006 ),a crit i cal healt h be n efits to astro n auts (Berk o vich et al.,2009;Lane and Feeback,2002 ).We next exami n ed whether the qua l ity of the lettuce changes unde r long-t e rm ope r at- ing co n ditions of the HT P .The quality of the lettu c es ha r - vested at the first,fifth and tenth root modu l e,was determined .Fig.7A suggest e d that the crude fiber contentwas at the same level (125–153 g kg À1dry wei g ht)for all lettuces from different modules .This was significantlylower than that (164–198 g kg À1dry weight)of lettuce from the local store .This difference in crud e fiber content of lettuces grown in the HTP an d pur c hased from the local store may be due to the vegeta b le maturit y an d cultural practices.Genera l ly speaking ,high-fiber contai n ing vegeta- bles do not have app e aling tast e propert i es (Hounsome et al.,2008 ).Ther e fore,we belie v e that the lettuces har- vested in the HTP have not only more tender and soft plant tissues,but also bette r tast e than that from the store.Ther e was also no significant difference in the content s of vita m ins and minerals of lettuces grown on different root modules Tabl e s 2and 3).Meanw h ile,a comp a rison of lettuces harvest e d in the HTP with pur c hased one s showe d a strong consis t ency in any of the vitamins analyze d .The mineral co n tents of lettuces ha r vested in the HT P ,with the excepti o n of calci u m and iron,wer e sim i lar to those found in the lett u ces from the store.These resul t s illus- trated that long-term operati o n of the HTP did not alter vegeta b le nutri t ion composi t ion to any great extent ,further validati n g suit a bility of the con figurations of the HTP .The observed varia t ions in calcium and iron are most likely due to different gro w th and manag e ment co n ditions.In fact,climate,nutri e nt solut i on compo s ition,and colle c tion time are all factors that might be responsi b le for the varia t ion of mineral content of vegetab l es (Laz i c et al.,2002;Zia-ur -Rehm a n et al.,2003 ).3.3.3.Nitrat e content of lettucesFig.5.View of lettuces after 40 days of cultivatio n in the HTP.Y.Fu et al./Advances in Space Research xxx (2013)xxx–xxx 5well as that from the store.As sho w n in Fig.7B,the aver- age nitr a te content of lett u ces grow n on different root mod -ules was 684 mg kg À1fres h weigh t,whic h was sli g htly lower than that of lettuces from the store (742mg kg À1 fresh weight),an d far less than the lim i t set of nitrate con -tent for lett u ces by Chin a(3000mg kg À1Fr e sh wei g ht, GB18406.1/2001)an d E uro p ean Union (2500mg kg À1 Fresh weight,E C1881 /2006).Thi s result indicated food per week at 0.3 kW.Long- t erm ope r ation of the HTP did not alter vegeta b le nutri t ion composi t ion to any great extent.Moreov e r,the crude fiber and nitrate of the lettuces grown in the HTP were lower than that of lettu c es from the local grocery store .The efficiency of the HTP,based on the Q-criterion,was 7Â10À4g2mÀ3JÀ1,whi c h was be t ter than sim i lar faci l ities designe d previous l y.In summ a ry, the HTP sho w ed high producti v ity,stabl e qua l ity an d go o d efficiency in the proce s s of nor m ally growing lettuces,sug- gesting that the HTP con figurations ap p ear to be an inter-pariso n of biomass (A)and moisture content (B)of lettuces grown in the HTP and purchas e d from the store.fw,fresh wight;RM, lettuce sample from root modules of the HTP;LS,lettuce sample from local grocery store..parison of crude fiber content (A)and nitrate content (B)in lettuces grown in the HTP and purchas e d from the store 1th,5th,10 th: lettuce samples from the first,fifth and tenth modules of the HTP.LS, lettuce sample from local grocery store.Table 2Vitamins content of lettuces grown in the HTP.Sample resource b-carotene (provitA)mg/100 gfw ±sd (1)Ascorbic acid (C)mg/100 g fw ±sdThiamin (B1)l g/100 gfw ±sdRiboflavin(B2)l g/100 gfw ±sdNiacin (B3)mg/100 gfw ±sdPantothenic acid(B5)mg/100 gfw ±sdFolate (B9)l g/100 gfw ±sdFirstmodule4.58 ±0.48 a(2)16.47 ±3.15 a30.27 ±8.89 a57.88 ±2.42 a0.38 ±0.02 a0.14 ±0.01 a33.76 ±3.41 a Fifthmodule4.27 ±0.32 a18.93 ±3.19 a44.00 ±7.55 a71.13 ±14.77 a0.37 ±0.04 a0.14 ±0.01 a35.16 ±5.26 a Tenthmodule4.87 ±0.71 a16.87 ±5.91 a33.33 ±6.65 a70.13 ±14.2 a0.35 ±0.05 a0.15 ±0.02 a33.73 ±4.16 a Localgrocerystore4.48 ±0.55 a18.80 ±2.33 a38.33 ±11.06 a69.82 ±5.46 a0.35 ±0.02 a0.15 ±0.01 a37.93.±1.87a(1)fw =fresh weight,sd =standard deviation.(2)Same letter indicates no significant difference(P>0.05).esting design for space vegeta b le pro d uction.How e ver,many issue s in the HT P are worthy of studi e s yet,such as the furt h er impro v ement of produ c tion efficiency,plant diseas e control under the long-t e rm operation ,an d the cul- tivation techni q ues for other plan t specie s .Ackno w ledgm e ntThis work was supp o rted by Grant s from Ministry of Science and Techn o logy of China (2012DFR30570 ).Appen d ix A.Supplem e ntar y dataSupplement a ry data associ a ted with this article can be found ,in the online versi o n,at /10.1 016/ j.asr.2 013.03 .020 .Refer ence sAlfawaz,M.A.Chemical composition of hummayd (Rumex vesicarius )grown in Saudi Arabia.J.Food Compos.Anal.19,552–555,2006 .AOAC.,2000.Official methods of analysis of AOAC (Association of Official Analytical Chemists)International,17th ed.OAC Interna- tional,Gaithersburg ,MD,2000.Avercheva,O.V.,Berkovich,Yu A.,E rokhin,A.N.,Zhigalova ,T.V.,Pogosyan,S.I.,Smolyanina ,S.O.Growth and photosyn t hesis of Chinese cabbage plants grown under light-emi t ting diode-based light source.Russ.J.Plant Physiol.56,14–21,2009 .Bekovich,Yu A.Evaluation of planting surfaces for crop production in micrograv i ty.Adv.Space Res.26,271–279,2000 .Berkovich,Yu A.,Krivobo k ,N.M.,Smolianina,S.O.,Erokhin,A.N.,2005.Developmen t and operation of a space-oriente d salad machine phytoco n veyer.SA E Technical Paper #2005-01- 2842.Berkovich,Yu A.,Tynes,G.,Levine,H.,2002.Evaluation of an ebb and flow nutrient delivery technique applicable to growing plants in micrograv i ty.SAE Technical Paper #2002-1-238 3.Berkovich,Yu A.,Chetirkin,P.V.,Wheeler,R.M.,Sager,J.C.Evaluating and optimizing horticultural regimes in space plant growth facilities.Adv.Space Res.34,1612–1618,2004a .Berkovich,Yu.A.,Krivobok,N.M.,Sinyak,Y.Y.,Smolyani n a,S.O.,Grigor i ev,Yu.I.,Romanov,S.Yu.,Guissenber g ,A.S.Develop i ng a vitamin greenhouse for the life support system of the internat i onal space station and for future interplanet a ry missions.Adv.Space Res.34,1552–1557,2004b .Berkovich,Yu A.,Smolyan i na,S.O.,Krivobok,N.M.,Erokhin,A.N.,Agureev,A.N.,Shanturin,N.A.Vegetable production facility as a part of a closed life support system in a Russian Martian space flight scenario.Adv.Space Res.44,170–176,2009 .Briggs,W.R.,Beck,C.F.,Cashmore ,A.R.,et al.The phototropin family of photore c eptors.Plant Cell 13,993–997,2001 .Briggs,W.R.,Olney,M.A.Photoreceptors in plant photom o rphogenesis to date.Five phytoch r omes,two crypto c hromes,one phototrop i n,and one superch r ome.Plant Physiol.125,85–88,2001 .Erokhin,A.N.,Berkovich ,Yu.A.,Smollanina,S.O.,Krivobok,N.M.,Agureev,A.N.,Kalandarov,S.K.A cylindrica l salad growth facility with a light-emi t ting diodes unit as a component for biological life support system for space crews.Adv.Space Res.38,1240–1247,2006 .Goins,G.D.,Yorio,N.C.,Sanwo,M.M.,Brown,C.S.Photomor p hogen- esis,photosyn t hesis,and seed yield of wheat plants grown under red light-emi t ting diodes (LE Ds)with and without supplement a l blue lighting.J.Exp.Bot.48,1407–1413,1997 .Guevara,J.C.,Yahia,E.M.,Brito de la Fuente,E.,Biserka,S.P.Effects of elevate d concentratio n s of CO 2in modified atmosphere packaging on the quality of prickly pear cactus stems (Opuntia spp.).Postharve s t Biol.Technol.29,167–176,2003 .Hounsom e ,N.,Hounsom e , B.,Tomos, D.,Edwards-J o nes,G.Plant metabolite s and nutritional quality of vegetables .J.Food Sci.73,R48–R65,2008 .Kim,H.H.,Goins,G.D.,Wheeler,R.M.,Sager,J.C.Green-ligh t supplem e ntation for enhanced lettuce growth under red- and blue- light-emi t ting diodes.HortScienc e 39,1617–1622,2004a .Table 3Minerals content of lettuces grown in the HTP.Sample resource Macroe l ements (mg/100g fw ±sd(1))Micronutrie n ts (mg/100g fw ±sd)Potassium (K)Sodium (Na)Calcium (Ca)Phosphorus(P)Magnesium (Mg)Iron (Fe)Mangan e se (Mn)Copper (Cu)Zinc (Zn)First module 226.1 ±19.5a (2)13.0 ±2.2a88.5 ±6.7a23.8 ±3.0a32.0 ±1.4 a1.54 ±0.2a0.32 ±0.03a0.031 ±0.004a0.28 ±0.01aFifth module 227.6 ±10.6a15.4 ±3.6a88.2 ±1.1a26.1 ±2.2a32.7 ±3.4a1.95 ±0.3ab0.34 ±0.00a0.030 ±0.002a0.27 ±0.03aTenth module 210.5 ±27.8a14.3 ±2.1a80.2 ±6.1a23.5 ±1.5a31.7 ±3.7a2.09 ±0.6ab0.31 ±0.02a0.032 ±0.003a0.28 ±0.02aLocal grocery store218.5 ±23.0a15.6 ±2.7a58.6 ±2.7b25.6 ±2.4a32.0 ±5.4a5.28 ±0.4b0.34 ±0.02a0.046 ±0.004b0.28 ±0.03a(1)fw =fresh weight,sd =standard deviation.(2)Different letters indicate a significant difference at P <0.05.Table 4Efficiency comparison of different space vegetable production facilities based on Q-criterio n .Name Paramete r s Q-criterion (g 2m À3J À1)Ref.Chamb e r volume (m 3)Consumed power (W)Maximal salad produc t ivity (g/day)Vitacycle 0.75 1000 150 3.5 Â10À4(Berkovi c h et al.,2004b )Salad machine 1.31300865.1 Â10À5Berkovich et al.,2004b )Horn-typeProducer0.12 300 45.27.0 Â10À4In present studyY.Fu et al./Advances in Space Research xxx (2013)xxx–xxx7Kim,H.H.,Goins,G.D.,Wheeler,R.M.,Sager,J.C.Stomatal conduc-tance of lettuce grown under or exposed to different light qualities.Ann.Bot.94,691–697,2004b .Kliss,M.,Heyenga,A.G.,Hoehn ,A.,Stodieck,L.S.Recent advances in technologie s required for a “Salad Machine ”.Adv.Space Res.26,263–269,2000 .Lane,H.W.,Feeback,D.L.History of nutrition in space flight:Overview .Nutrition 18,797–804,2002 .Lazic,B.,Lazic,S.,Sekulic ,P.Effect of species and variety of the content of macroelem e nts and micronut r ients in lettuce.Acta Hortic.579,609–613,2002 .Levine,L.,Pare,P.W.Antioxidan t capacity reduced in scallions grown under elevated CO 2independent of assayed light intensity.Adv.Space Res.44,887–894,2009 .Mccall,D.,Willumsen,J.Effects of nitrogen availabi l ity and supplemen- tary light on the nitrate content of soil-grown lettuce.J.Hortic.Sci.Biotechno l .74,458–463,1999 .McKeehen,J.D.,Smart,D.J.,Mackow i ak,C.L.,Wheeler,R.M.,Nielsen,S.S.Effect of CO 2levels on nutrient content of lettuce and radish.Nat.Artif.18,85–92,1996 .Mitchell,C.Bioregene r ative life-suppo r t systems.Am.J.Clin.Nutr.60,820S–824S,1994 .Morrow,R.,Remiker,R.,Mischnick,M.,Tuominen,L.,Lee,M.,Crabb,T.,2005.a low equivalent system mass plant growth unit for space exploratio n .SAE Technical Paper #2005-01-28 43.Smith,S.M.,Zwart,S.R.Nutritional biochemistry of spaceflight.Adv.Clin.Chem.46,87–130,2008 .Sychev,V.N.,Levinsk i kh,M.A.,Gostimsky ,S.A.,Bingham,G.E.,Podolsky,I.G.Spaceflight effects on consecutive generation s of peas grown onboard the Russian segment of the internat i onal space station.Acta Astrona u t.60,426–432,2007 .Tong,L.,Hu,D.,Liu,H.,Fu,Y.,Li,M.,Du,F.,Hu,E.Gas exchange between humans and multibiologic a l life support system.E col.E ng.37,2025–2034,2011a .Tong,L.,Yu,X.,Liu,H.Insect food for astronauts:gas exchange in silkworms fed on mulberry and lettuce and the nutritional value of these insects for human consumptio n during deep space flights.Bull.Entomol.Res.101,613–622,2011b .Wheeler,R.M.Potato and human exploratio n of space:some observa- tions from NASA-spo n sored controlled environment studies.Potato Res.49,67–90,2006 .Wheeler,R.M.,2009.Roadmaps and strategies for crop research for bioregenerative life support systems a compilation of findings from NASA’s Advanced life support meetings.NASA/TM -2009-2147 68.Wheeler,R.M.,Mackowiak ,C.L.,Sager,J.C.,Yorio,N.C.,Knott,W.M.,Berry,W.L.Growth and gas exchang e by lettuce stands in a closed,controlled environment.J.Am.Soc.Hortic.Sci.119,610–615,1994 .Yorio,N.C.,Goins,G.D.,Kagie,H.R.,Wheeler,R.M.,Sager,J.C.Improving spinach,radish,and lettuce growth under red light-emi t ting diodes (LEDs)with blue light supplemen t ation.HortScienc e 36,380–383,2001 .Zia-ur-Reh m an,Z.,Islam,M.,Shah,W.H.E ffect of microwave and conventional cooking on insoluble dietary fibre components of vegetables.Food Chem.80,237–240,2003 .8Y.Fu et al./Advances in Space Research xxx (2013)xxx–xxx。