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WASHINGTON, June 6 (Xinhua) -- Women who have higher levels of the appetite-controlling hormone leptin have fewer symptoms of depression, and this apparent inverse relationship is not related to body mass index (BMI), a new study finds. The results were presented Monday at The Endocrine Society's 93rd Annual Meeting in Boston, the United States."Animal data suggest that leptin may reduce anxiety and improve depression. Our study in women suggests that leptin may indeed have antidepressant qualities," said the study's lead author, Elizabeth Lawson, of Massachusetts General Hospital and Harvard Medical School in Boston.Leptin, the product of fat cells, signals satiety, or fullness. It is low in thin women and high in obese women, according to Lawson. She also said there is an increased prevalence of anxiety and depression in certain conditions in which leptin levels are typically low. These include the eating disorder anorexia nervosa, in which there is abnormally low weight and body fat, and functional hypothalamic amenorrhea, in which women have stopped menstruating despite having normal weight."It is unknown whether low leptin levels contribute to the development of mood disorders in these women," Lawson said.She and her co-workers studied the relationship between leptin levels and symptoms of anxiety and depression in 64 women. Fifteen of the women had anorexia nervosa, 12 were normal weight with hypothalamic amenorrhea, 20 were normal weight and in good health, and 17 were overweight or obese but still healthy.All subjects were asked questions to assess symptoms of depression and anxiety, with high scores indicating more symptoms. Besides measuring leptin levels in the blood, the researchers assessed the women's BMI, a measure of weight for height.The relationship between leptin and depression symptoms was independent of BMI. This finding indicates that leptin may mediate symptoms of depression and that this effect is not a function of low weight, Lawson said."Further research administering leptin to humans will be important in understanding whether this hormone has a potential role in the treatment of depression," she said.

SAN FRANCISCO, July 6 (Xinhua) -- Facebook on Wednesday introduced a new video calling feature powered by Skype and some improvements to the chat designs on the social networking site.According to Facebook, users can reach video calling from a new "Call" button on a friend's profile or from the chat panel after downloading a Skype application. A recipient will receive an alert that they are being called and can then accept or decline.At the press event held at Facebook headquarters in Palo Alto, California, CEO Mark Zuckerberg said the feature will begin with one-on-one video chat. Skype CEO Tony Bates, whose company has been acquired by Microsoft, said Skype is considering having its paid product within the Facebook product.The social networking company also introduced "Ad Hoc Group Chat", which enables users to start a group chat instantly without creating a group with those multiple friends at first. The new group chat feature is also available for Facebook's mobile interfaces.Facebook also introduces a sidebar that lists the people a user messages most, enabling users to chat with close friends, professional contacts or co-workers without being interrupted. The sidebar can adjust with the size of users' browser window and automatically appears when the window is wide enough.In the opening remarks at the press event, Zuckerberg confirmed that Facebook had surpassed 750 million monthly active users. He said the company had declined to announce the number earlier because it has become focused on other metrics, like how actively users are sharing information.The CEO said users are now sharing 4 billion "things" on Facebook every day, which grew at an exponential rate compared to the amount users share a year ago."Social networking is at an inflection point," said Zuckerberg, adding that he believes social networking now is more about the strength of connecting people rather than the quantity of users or ubiquity of the technology.Zuckerberg presented a graph to show how Facebook product launches have helped drive the growth of sharing. He said the social network expects more innovations from other companies involved in everything from music to communication to help drive the growth.

WASHINGTON, Sept. 14 (Xinhua) -- Controlling diabetes may someday involve mining stem cells from the lining of the uterus, Yale School of Medicine researchers report in a new study published Wednesday in the journal Molecular Therapy. The team treated diabetes in mice by converting cells from the uterine lining into insulin-producing cells.The endometrium or uterine lining, is a source of adult stem cells. These cells generate uterine tissue each month as part of the menstrual cycle. Like other stem cells, however, they can divide to form other kinds of cells.Led by Yale Professor Hugh Taylor, the researchers bathed endometrial stem cells in cultures containing special nutrients and growth factors. Responding to these substances, the endometrial stem cells adopted the characteristics of beta cells in the pancreas that produce insulin. Over the course of a three- week incubation process, the endometrial stem cells took on the shape of beta cells and began to make proteins typically made by beta cells. Some of these cells also produced insulin.After a meal, the body breaks food down into components like the sugar glucose, which then circulates in the blood. In response, beta cells release insulin, which allows the body's cells to take in the circulating glucose. In this study, Taylor and his team exposed the mature stem cells to glucose and found that, like typical beta cells, the cultured cells responded by producing insulin. The team then injected diabetic mice with the mature, insulin-making stem cells. The mice had few working beta cells and very high levels of blood glucose.Mice that did not receive the stem cell therapy continued having high blood sugar levels, developed cataracts and were lethargic. In contrast, mice that received the cell therapy were active and did not develop cataracts, but the animals' blood sugar levels remained higher than normal.The Yale team's findings suggest that endometrial stem cells could be used to develop insulin-producing islet cells, which are found in the pancreas. These islet cells could then be used to advance the study of islet cell transplantation to treat people with diabetes.Taylor said in a statement that the next step in the research will be to verify how long this treatment remains effective.

WASHINGTON, June 2 (Xinhua) -- When humans see red, their reactions become both faster and more forceful, according to a new study published this week in the U.S. bimonthly journal Emotion.The findings may have applications for sporting and other activities in which a brief burst of strength and speed is needed, such as weightlifting. But the authors caution that the color energy boost is likely short-lived.The study measured the reactions of students in two experiments. In the first, 30 fourth-through-10th graders pinched and held open a metal clasp. Right before doing so, they read aloud their participant number written in either red or gray crayon. In the second experiment, 46 undergraduates squeezed a handgrip with their dominant hand as hard as possible when they read the word "squeeze" on a computer monitor. The word appeared on a red, blue, or gray background.In both scenarios, red significantly increased the force exerted, with participants in the red condition squeezing with greater maximum force than those in the gray or blue conditions. In the handgrip experiment, not only the amount of force, but also the immediacy of the reaction increased when red was present.The colors in the study were precisely equated in hue, brightness, and chroma (intensity) to insure that reactions were not attributable to these other qualities of color."Red enhances our physical reactions because it is seen as a danger cue," explains coauthor Andrew Elliot, professor of psychology at the University of Rochester and a lead researcher in the field of color psychology. "Humans flush when they are angry or preparing for attack," he explains. "People are acutely aware of such reddening in others and it's implications."But threat is a double-edged sword, argue Elliot and coauthor Henk Aarts, professor of psychology at Utrecht University, in the Netherlands. Along with mobilizing extra energy, "threat also evokes worry, task distraction, and self-preoccupation, all of which have been shown to tax mental resources," they write in the paper.In earlier color research, exposure to red has proven counterproductive for skilled motor and mental tasks: athletes competing against an opponent wearing red are more likely to lose and students exposed to red before a test perform worse.

SAN FRANCISCO, June 20 (Xinhua) -- Google and the British Library announced Monday that the Internet search giant will digitize 250,000 out-of-copyright books from the library's collections, making up to 40 million pages from 1700 to 1870 available to the public online.In a joint statement, the British Library and Google said they will work in partnership over the coming years to deliver the content free through Google Books and the library's website, and full text search, download and reading will be available. Google will cover all digitization costs.The project is going to cover a huge range of printed books, pamphlets and periodicals dated 1700 to 1870, a period of political and technological turmoil, from the Industrial Revolution to the French Revolution, from the introduction of the income tax in Britain and the invention of the telegraph and railway.It will include material in a variety of major European languages and will focus on books that are not yet freely available in digital form online, said the statement.Since December 2004, Google has announced partnership with some 40 high-profile university and public libraries, planning to digitize and make available some 15 million volumes within a decade through Google Books service.The project has triggered controversy as publisher and author associations oppose the plan to put copyrighted titles online in a class action lawsuit.

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