2013年4月22日星期一

Protein Quality Evaluation of Animal Food Proteins by In-Vitro Methodologies




Meat is a valuable food for human.It provides us complete protein, vitamin and all kinds of other nutrition.It also provides us some nutrition which is rare in vegetarian diet,such as zinc, vitamin B12, Calcium, iron.Besides,the meat quality is important.There is a research evaluat the protein quality of some animal food sources:
In this study, the protein quality evaluation of these animal food sources, highly produced and consumed in Sonora, is proposed, using in-vitro methodologies. Four different species, from each aquatic and terrestrial origin, were selected. Samples of lean muscle were used in all cases. Various in-vitro methodologies for protein quality evaluation were selected, alternatives to the animal bioassays: % digestibility, Total amino acid analyses (HPLC), PDCAAS, computerized PER calculations (C-PER and DC-PER) and total collagen contents. % in-vitro digestibility presented significant differences among samples from terrestrial species, but muscle from aquatic species did not showed significant differences. All sources of proteins, both aquatic and terrestrial proved to be rich sources of essential amino acids. PDCAAS was unable to establish significant differences in protein quality among sources of protein from different origin. Both methods C-PER and DC-PER were more exact in their results and were able to detect significant differences among samples of different origin. An important finding was the great difference in the total collagen content between aquatic and terrestrial sources of proteins, where terrestrial muscle proteins had almost 10-time more collagen than aquatic protein sources. However, these collagen contents did not seem to have a significant influence in the protein quality of these animal proteins. These muscle proteins, from both aquatic and terrestrial species, confirmed to have a high protein quality and some of the in-vitro methodologies used in this study represent a valuable alternative to the animal bioassays.








2013年4月21日星期日

Will human continue to live longer in future?



Recent discoveries show steady improvements in life expectancy during modern decades.Yes,better food supply and nutrition, better hygiene,the popularization of health knowledge does make me enjoy a longer life.According to Wikipedia,a French has ever lived for 122 years,a Japanese is 116 years old so far still alive.Will human continue to live longer in future?A research named < Predicting human lifespan limits>published in Nature Science takes industrialized countries as an example,and analyses the limits that will affect our “longevity”.You can read this research for more detail.



2013年4月18日星期四

Which city planning makes for reducing bicycle crash



Compared with cars,bike seems to have some advantages that cars can’t instead.Such as: environmental protection, save money , no traffic jams and good for health.Thus,some people prefers bikes.But there lies a big problem for riders: safety.A research from Scientific Research Publishing analyses 5 years of bicycle crash data from the city of San Francisco and make recommendations on how planners and design professionals can keep bicyclist safety considerations in mind.You can learn more by reading the full article.





Ricin, The Poison Mailed To President Obama



Ricin is one of the most poisonous substances on Earth, it's scarily easy to make, and somebody is mailing it to the President and at least one U.S. senator. What it is, how it works?

How poisonous is it?
Oh, man. Very. It's dangerous in just about any way it gets into your system, though ingesting (eating) it is about the least dangerous way. Injecting or inhaling requires about a thousand times less ricin to kill a human than ingesting, and that's a very small amount indeed. An average adult needs only 1.78mg of ricin injected or inhaled to die; that's about the size of a few grains of table salt--which ricin resembles visually.

How does it work?
Ricin, a toxic protein, infects cells, blocking their ability to synthesize their own protein. Without cells making protein, key functions in the body shut down; even in survivors, permanent organ damage is often the result of ricin poisoning. It's a highly unpleasant way to be poisoned: within six hours, according to the Center for Disease Control, victims who have ingested ricin will feel gastrointestinal effects like severe vomiting and diarrhea, which can lead to serious dehydration. Then the ricin infects the cells of the vital gastrointestinal organs as they pass through the body, leading to the failure of the kidneys, liver, and pancreas.
Inhalation of ricin has a different effect, since the ricin proteins aren't interacting with the same parts of the body. Instead of gastrointestinal problems, you'll develop a vicious, bloody cough, your lungs will fill with fluid, and eventually you'll lose your ability to breathe, causing death. Injection, too, is different, depending on where you've been injected, but will generally result in vomiting and flu-like symptoms, swelling around the place of injection, and eventually organ failure as your circulatory system passes the protein around the body. Death from inhalation or injection usually occurs about three to five miserable, agonizing days after contact.
Interestingly, there aren't any immediate symptoms, and indeed there can be a significant delay before symptoms show themselves, up to a day or two.
Exposure on the skin is generally not fatal, though it may cause a reaction that can range from irritation to blistering.

How does it stack up against other poisons?
Well, that depends on what your aim is. Ricin is much easier to produce than other popular biological weapons like botulinum, sarin, and anthrax, but it is not as potent as any of those, which limits its effectiveness as a weapon. It also is not very long-lived; the protein can age and become inactive fairly quickly compared to, say, anthrax, which can remain dangerous for decades. There were experiments back around World War I attempting to make wide-scale ricin weapons, packaging it into bombs and coating bullets in it, but these proved not particularly effective and also violate the Hague Convention's agreements on war crimes, so the US discarded ricin.
It's much more effective, weapon-wise, as a close-contact, small-target weapon--by injecting, as with Georgi Markov, or by putting small particles into an aerosol spray and blasting a target. It's also not contagious, which limits its effectiveness as a tool of biological warfare. But it's considered highly dangerous partly because it's still outrageously toxic and partly because it takes no great skill to produce.

So it's not hard to make?
Well...no. Like, not at all. It's made from the byproduct of the castor oil manufacturing process. You take the "mash" of the castor oil seeds, which contain around 5-10 percent ricin, and perform a process called chromatography. Chromatography is a blanket term for a set of techniques used to separate mixtures, usually by dissolving in liquid or gas. The US government has done its best to eradicate recipes for ricin from the internet, sort of; a patent was filed back in 1962 for ricin extraction, and the Patent Office took it off the publicly available server in 2004 for safety reasons. That said, the recipe is super easy to find; here at the PopSci offices, I'm blocked from listening to Rdio on my work computer, but I found a recipe to make an outrageously deadly poison in about a minute.
The techniques involved are undergraduate-level chemistry, creating a slurry with the castor bean mash and filtering with water and then a few easily-found substances like hydrochloric acid.

It comes from castor beans?
Ricin is a highly toxic protein that's extracted from the seed of the castor plant, often called a "castor bean" or "castor oil bean," despite not technically being a bean. The castor plant is extremely common; it's used as an ornamental plant throughout the western world, prized for its ability to grow basically anywhere as well as its pretty, spiky leaves and weird spiny fruits. It's also an important crop; the seeds are full of oil, and castor oil is used for lots of legitimate purposes. It's a common laxative, for one thing, and since it's more resistant to high temperatures than other kinds of vegetable oils, it's a nice alternative to petroleum oil in engines.

Wait, but you can eat it? So how is this a poison?
Ah, yes. Castor oil is perfectly safe, according to the FDA and your grandma, but ricin is not castor oil. Castor seeds are still poisonous; a study says that a lethal dose of castor seeds for adults is about four to eight seeds. But the oil itself does not contain ricin; the ricin protein is left behind in the "castor bean mash" after the oil is extracted from the seed. Poisoning from eating the seed itself is rare.

Have there been cases of ricin poisoning in the past?
You mean, beyond the several times it's been featured as a major plot point in Breaking Bad? Sure! The most famous is probably the assassination of Georgi Markov in 1978. Markov was a Bulgarian novelist, playwright, journalist, and dissident, and was murdered by the Bulgarian secret service, with assistance from the KGB, by ricin injection. He was crossing a bridge when he was jabbed in the leg with an umbrella, which delivered a ricin pellet into his bloodstream. He died three days later of ricin poisoning.
There are plenty of incidents of people arrested for attempting (or, more often, succeeding) to make ricin; it's a pretty easy poison to make. In fact, there was even another ricin-in-the-envelope attempt made back in 2003--a person identifying as "Fallen Angel" sent letters filled with ricin to the White House, apparently as a result of some new trucking regulations (seriously). "Fallen Angel" was never found, but the letters were intercepted and did not cause any injury.

How dangerous are these envelopes filled with ricin?
The envelope strategy has more to do with potential ease of getting the poison close to targets than its strength as a delivery system. If you're targeting the President of the United States, it's easier and more anonymous to mail a letter than to try to get close to him with an umbrella modified for ricin-stabbing. But it's not a great way to poison someone with ricin. Assuming the letter actually got into the target's hands, of the three ways ricin can get into a person's system (inhalation, injection, ingestion), only one--inhalation--is really possible, and it's not that likely.
Inhalation as a weapon is best accomplished through a mist, ideally delivered through an aerosol. But that's not possible in a letter full of powder. It's possible that small granules of ricin could be released into the air and inhaled when handling the letter, but it is not an effective way to poison someone. And whoever's sending these letters evidently doesn't know that the government set up an elaborate mail-screening system after the 2001 Anthrax scare.

(source:popsci)

2013年4月17日星期三

History, Present and Expected Future of Forests in Slovakia



Tree forests cover approximately 9.4 percent of the Earth's surface (or 30 percent of total land area), though they once covered much more (about 50 percent of total land area). They function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the biosphere.But it has been significantly harmed by human for all purposes.What the future forests will be like? Researchers from Forest Ressearch Institute of Zvolen made a guess in the paper published in American Journal of Plant Sciences:

In this paper, we briefly summarize the problems that have been affecting Slovakian forestry in the past, in the present and are expected in the future. In the past, the forests in Central Europe were significantly harmed by the development of mining, metallurgy, wood processing industry, agriculture and grazing of sheep and cattle. Many areas have been completely deforested. Fundamental change occurred in the 18th Century, when the regulations about forest management, declared by Empress of the Austro-Hungarian monarchy Maria Therese, came into force. With the changing level of forest cover, there have been changing as well the problems in the forestry. Forests in Slovakia are nowadays dealing with the climate change, which is causing extreme weather fluctuations. It is connected with the emergence of abiotic disturbances after which usually occurs activation of biotic harmful agents. We expect that the most serious problem of forests in the future will be their state of health. We expect an increase representation of thermophilic tree species (beech and oak) at the expense of upland trees such as spruce. An important role will be played by the invasive species of plants, fungi and animals that can compete with native species and their habitats or in the situation of the absence of their reducents these can cause serious economic and environmental damage.

(source:SCIRP/ Plant Sciences)

2013年4月16日星期二

How much does the Boston Marathon explosion affects global economy?



On 15 April afternoon ,US time,an explosion attacks Boston marathon.It is the largest terrorist attack after 911 in USA.This terrorist event occurs around 3 PM, local time,one hour before New York stock market close.
Affected by this, Europe and America financial market are hard hitted. U.S. stocks closed sharply lower on Monday, 3 major indexes fell more than 1.7%. The VIX index sharply rose 40%. Commodities such as gold and silver are bear raid. Gold prices steep falls 9.3% on Monday,which is the one-day drop in 30 years.
The United States as the world’s only economic, political and military superpower, U.S. stocks’s cold must cause turmoil in the world. Asian stock markets fell in early trading on the 16th. The 2 cities of Shanghai and Shenzhen in China are both low on April 17, 2013. The intraday market rebound, the two markets both meteoric rise, At the close, the stock index reported 2194.85 points, up 0.59%, Shenzhen Component Index closed at 8852.42 points, up 1.36%.

“9.11” terrorist attack has ever destroyed the economy all over the world
“9.11” terrorist attack is undoubtedly the biggest terrorist attack which affects global economy. It made the US stock market stopped 4 days which has never happened before. US President Barack Obama has ever said in the 9.11 memorial concert:” More than a decade ago, the United States has experienced the darkest day in the history.”
Stock market is a barometer of a country's national economy.9.11 terrorist attacks not only caused a huge blow to America's economy, it also caused serious influence on the rest of the world economy. Spooked investors Sell all kinds of stock, fear that there is so much pain in global stock markets.In fact, after 9.11 events, fall of stock markets in Europe, Japan, and South America is more larger than Wall Street stock market.
The United Nations has issued a report says:”3.11 terrorist attacks will make this year's world economic growth rate reduced by one percent,with a  loss of $350 billion.”


Boston Marathon explode:has lead at least three people death and 130 injured







Police have confirmed two explosions at the Boston Marathon. The Boston Police are reporting at least three people are dead. More than 130 others are injured.

The dead included an 8-year-old boy, according to two law enforcement sources, the Boston Globe is reporting.

Boston police say no suspect has been taken into custody in connection with the explosions near the finish line of the Boston Marathon, despite reports from the New York Post of a 20-year-old suspect under guard at an undisclosed Boston hospital.

Police Commissioner Edward Davis also says the fire at a library a few kilometres away and more than an hour later doesn’t appear to be related to the explosions at the race on Monday. He says the fire may have been caused by an incendiary device.

A searchable list of Canadians in the race is at the bottom of this story.

Police say it’s too early to get into specifics about the nature of devices or whether shrapnel was involved.

Bloody spectators near the finish line of the Boston Marathon were being carried to the medical tent that had been set up to care for fatigued runners. Police wove through competitors as they ran back toward the course. Many of the injured suffered devastating injuries.

“These runners just finished and they don’t have legs now,” Roupen Bastajian, 35, a Rhode Island state trooper and former Marine, told the New York Times. “So many of them. There are so many people without legs. It’s all blood. There’s blood everywhere. You got bones, fragments. It’s disgusting.”

“There are a lot of people down,” said one man, whose bib No. 17528 identified him as Frank Deruyter of North Carolina.

He was not injured, but marathon workers were carrying one woman, who did not appear to be a runner, to the medical area as blood gushed from her leg. A Boston police officer was wheeled from the course with a leg injury that was bleeding.

An image of a fireball and smoke were shared on Twitter as well as what appears to be blood on the ground at the site of the reported explosion.

“There are people who are really, really bloody,” said Laura McLean, a runner from Toronto, who was in the medical tent being treated for dehydration when she was pulled out to make room for victims of the explosions. “They were pulling them into the medical tent.”