sábado, 20 de setembro de 2014

Should Our Kids Consume Dairy?

 

dairy.jpg - Michael Wildsmith/Photographer's Choice/Getty Images

Michael Wildsmith/Photographer's Choice/Getty Images

 

Snap 2014-09-20 at 18.24.05 

Updated September 16, 2014.

We are mammals.  Baby mammals survive on dairy, or they don’t survive at all. And, of course, it’s not just any dairy.  It’s the particular version of dairy unique to their own species: Mother’s milk.

So the first answer to the question posed in the title above is not only “yes,” but a yes derived directly from imperatives of evolutionary biology.

Our tendency to question the appropriateness of breast milk for newborn Homo sapiens over recent decades is testimony to a form of benighted arrogance our species seems to have invented.  Had natural selection not worked out the formula for feeding newborns for us over the eons, we wouldn’t be here to debate it.  Yet, we debated it just the same.

Thankfully, that debate seems to have reached appropriate closure.  Absent some contraindication, such as a transmissible infection, or a mother’s inability to provide the milk- breast milk is the overwhelmingly recommended first food for our children, as it should have been all along.  In the particular context of childhood obesity, the evidence for breast feeding as an important, early defense is quite strong.

So yes, our babies, like all other baby mammals, should start out consuming dairy.  That’s the easy answer.

Things get a bit more complicated after that, as we shift from the rather blatant answers of biology to the choices imparted by culture.  Should our children transition from the dairy derived from our own species, to that of another?

Personally, living in the U.S., I think so.  The evidence in support of health benefits from dairy consumption in childhood here is strong and consistent.  There is a particular benefit related to weight control and the prevention of obesity, just as there is for breast feeding.

But, it’s important to note, as I did in a recent column that explores these matters at greater length, that the benefits of dairy for Homo sapiens after weaning are legitimately debatable.

For one thing, there are other ways to get those benefits, and there is no clear case that the offspring of vegans would benefit from the addition of dairy to their diets.  There are Blue Zone populations that raise their children with no recourse to dairy after breast feeding, and the result is- well- Blue Zones.  There are also Blue Zone populations in the Mediterranean region for which dairy is a staple, albeit one of lesser apparent importance than some of the other features of the native diet. Blue Zone populations live longer and better than the rest of us, so whatever they do- works.  They illustrate well both the theme of healthful eating, and the opportunity select a favored variant on that theme.

For another, the benefits of dairy are a matter of context; of what is added to the diet, and what is removed.  If our children drink milk (of whatever kind) instead of soda, they are certainly trading up.  If they drink sweetened milk concoctions in lieu of water, they might well be trading down.  That is likely one of the reasons for the fairly strong, consistent association between dairy intake and weight control in the U.S.  Kids who drink a lot of soda tend to consume less dairy, and vice versa.

Ultimately, questions about dairy in the diets of our children become questions about dairy in our own diets, since we are far more likely to maintain dietary patterns when we live it together, rather than diet alone.  There are arguments both for and against habitual dairy intake by adults, encompassing the kind of dairy; dietary context; environmental impact; the treatment of animals; and our own genetic polymorphisms.

But in this one short column on a potentially complex topic, let’s stay focused and keep things simple.  Our own baby mammals should begin life, whenever possible, nourished by their mother’s milk.  In the U.S., where the prevailing alternatives are rather dubious, the inclusion of dairy in the diets of our children is associated with health benefit.  Those already committed to healthful diets that exclude dairy, however, should feel no pressure.  Those work, too.

Snap 2014-09-20 at 18.21.11

Tea May Help Prevent Diabetes And Cataracts

 


Add another line to the list of benefits from drinking tea: New research in animals suggests that tea may be a simple, inexpensive means of preventing diabetes and its ensuing complications, including cataracts. The report, scheduled to appear in the May 4 print issue of the American Chemical Society's Journal of Agricultural and Food Chemistry, was published March 31 on the journal's Web site. ACS is the world's largest scientific society.

Researchers fed green and black tea to diabetic rats for three months and then monitored the chemical composition of the rats' blood and eye lenses. At levels that would be equivalent to less than five cups of tea per day for a human, both teas significantly inhibited cataract formation relative to a control group which did not get tea, they say. The researchers found that both teas decreased glucose levels, which in turn affects other biochemical pathways that accelerate diabetic complications such as cataracts.

"Most people, scientists included, believe that green tea has more health benefits than black tea," says Joe Vinson, Ph.D., a chemist at the University of Scranton (Penn.) and lead author of the paper. In combination with Vinson's earlier research showing that green tea and black tea equally inhibit atherosclerosis -- a major risk factor for heart disease -- the findings suggest that both drinks could play a part in curbing two of the most widespread maladies in the United States today.

The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with a multidisciplinary membership of more than 158,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.


Story Source:

The above story is based on materials provided by American Chemical Society. Note: Materials may be edited for content and length.

The effects of soy and whey protein supplementation on acute hormonal reponses to resistance exercise in men

 


With protein supplement use by athletes on the rise, a group of researchers expanded upon prior research examining the effects of soy and whey protein supplementation on testosterone, sex hormone binding globulin (SHBG), and cortisol responses to an acute bout of resistance exercise. Their study, "The Effects of Soy and Whey Protein Supplementation on Acute Hormonal Reponses to Resistance Exercise in Men" is the 2014 Ragus Award Winner as Best Article from the Journal of the American College of Nutrition, the official publication of the American College of Nutrition.

For many resistance-trained men concerns exist regarding the production of estrogen with the consumption of soy protein when training for muscle strength and size. Thus, the purpose of this investigation was to examine the effects of soy and whey protein supplementation on sex hormones following an acute bout of heavy resistance exercise in resistance-trained men.

10 resistance-trained men in their early 20s were divided into 3 supplementation treatment groups: (1) whey protein isolate, (2) soy protein isolate, or (3) a maltrodextrin placebo control. No other supplements were allowed. Vegetarians, vegans, or subjects who consumed high-protein diets were excluded from the study. For 14 days, participants would ingest 20g of their assigned supplement at the same time each morning. The participants would then perform 6 sets of heavy resistance squats at 10 reps each using 80 percent of their maximum lifting weight.

"Our main findings demonstrate that 14 days of supplementation with soy protein does appear to partially blunt serum testosterone. In addition, whey influences the response of cortisol following an acute bout of resistance exercise by blunting its increase during recovery. Protein supplementation alters the physiological responses to a commonly used exercise modality with some differences due to the type of protein utilized," wrote the researchers.


Story Source:

The above story is based on materials provided by Taylor & Francis. Note: Materials may be edited for content and length.


Journal Reference:

  1. William J. Kraemer, Glenn Solomon-Hill, Brittanie M. Volk, Brian R. Kupchak, David P. Looney, Courtenay Dunn-Lewis, Brett A. Comstock, Tunde K. Szivak, David R. Hooper, Shawn D. Flanagan, Carl M. Maresh, Jeff S. Volek. The Effects of Soy and Whey Protein Supplementation on Acute Hormonal Responses to Resistance Exercise in Men. Journal of the American College of Nutrition, 2013; 32 (1): 66 DOI: 10.1080/07315724.2013.770648

Graphene sensor tracks down cancer biomarkers

 

September 19, 2014

Institute of Physics

An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer. The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients.


This is an illustration of an epitaxial graphene channel biosensor for detection of targeted 8-hydroxydeoxyguanosine (8-OHdG) biomarker. (A) Schematic of MLEG device (B) Thin film of covalently attached nitro phenyl (PhNO2) groups on the MLEG channel. (C) Attachment of the 'bioreceptor' antibody anti-8-OHdG to the amine terminated MLEG channel and subsequent detection of 8-OHdG.

An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer.

The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients.

The biosensor has been presented today, 19 September, in IOP Publishing's journal 2D Materials.

To develop a viable bionsensor, the researchers, from the University of Swansea, had to create patterned graphene devices using a large substrate area, which was not possible using the traditional exfoliation technique where layers of graphene are stripped from graphite.

Instead, they grew graphene onto a silicon carbide substrate under extremely high temperatures and low pressure to form the basis of the biosensor. The researchers then patterned graphene devices, using semiconductor processing techniques, before attaching a number of bioreceptor molecules to the graphene devices. These receptors were able to bind to, or target, a specific molecule present in blood, saliva or urine.

The molecule, 8-hydroxydeoxyguanosine (8-OHdG), is produced when DNA is damaged and, in elevated levels, has been linked to an increased risk of developing several cancers. However, 8-OHdG is typically present at very low concentrations in urine, so is very difficult to detect using conventional detection assays, known as enzyme-linked immunobsorbant assays (ELISAs).

In their study, the researchers used x-ray photoelectron spectroscopy and Raman spectroscopy to confirm that the bioreceptor molecules had attached to the graphene biosensor once fabricated, and then exposed the biosensor to a range of concentrations of 8-OHdG.

When 8-OHdG attached to the bioreceptor molecules on the sensor, there was a notable difference in the graphene channel resistance, which the researchers were able to record.

Results showed that the graphene sensor was capable of detecting 8-OHdG concentrations as low as 0.1 ng mL-1, which is almost five times more sensitive compared with ELISAs. The graphene biosensor was also considerably faster at detecting the target molecules, completing the analysis in a matter of minutes.

Moving forward, the researchers highlight the potential of the biosensor to diagnose and monitor a whole range of diseases as it is quite simple to substitute the specific receptor molecules on the graphene surface.

Co-author of the study Dr Owen Guy said: "Graphene has superb electronic transport properties and has an intrinsically high surface-to-volume ratio, which make it an ideal material for fabricating biosensors.

Now that we've created the first proof-of-concept biosensor using epitaxial graphene, we will look to investigate a range of different biomarkers associated with different diseases and conditions, as well as detecting a number of different biomarkers on the same chip."


Story Source:

The above story is based on materials provided by Institute of Physics. Note: Materials may be edited for content and length.


Journal Reference:

  1. Z Tehrani, G Burwell, M A Mohd Azmi, A Castaing, R Rickman, J Almarashi, P Dunstan, A Miran Beigi, S H Doak, O J Guy. Generic epitaxial graphene biosensors for ultrasensitive detection of cancer risk biomarker. 2D Materials, 2014; 1 (2): 025004 DOI: 10.1088/2053-1583/1/2/025004

Simple test can help detect Alzheimer's before dementia signs show, study shows

 

September 19, 2014

York University

A simple test that combines thinking and movement can help to detect heightened risk for developing Alzheimer's disease in a person, even before there are any telltale behavioural signs of dementia, researchers report, adding that the findings don't predict who will develop Alzheimer's disease, but they do show there is something different in the brains of those who go on to be diagnosed with Alzheimer's.


York University researchers say a simple test that combines thinking and movement can help to detect heightened risk for developing Alzheimer's disease in a person, even before there are any telltale behavioural signs of dementia.

Faculty of Health Professor Lauren Sergio and PhD candidate Kara Hawkins who led the study asked the participants to complete four increasingly demanding visual-spatial and cognitive-motor tasks, on dual screen laptop computers. The test aimed at detecting the tendency for Alzheimer's in those who were having cognitive difficulty even though they were not showing outward signs of the disease.

"We included a task which involved moving a computer mouse in the opposite direction of a visual target on the screen, requiring the person's brain to think before and during their hand movements," says Sergio in the School of Kinesiology & Health Science. "This is where we found the most pronounced difference between those with mild cognitive impairment (MCI) and family history group and the two control groups."

Hawkins adds, "We know that really well-learned, stereotyped motor behaviours are preserved until very late in Alzheimer's disease." These include routine movements, such as walking. The disruption in communication will be evident when movements require the person to think about what it is they are trying to do.

For the test, the participants were divided into three groups -- those diagnosed with MCI or had a family history of Alzheimer's disease, and two control groups, young adults and older adults, without a family history of the disease.

The study, Visuomotor Impairments in Older Adults at Increased Alzheimer's Disease Risk, published in the Journal of Alzheimer's Disease, found that 81.8 per cent of the participants that had a family history of Alzheimer's disease and those with MCI displayed difficulties on the most cognitively demanding visual motor task.

"The brain's ability to take in visual and sensory information and transform that into physical movements requires communication between the parietal area at the back of the brain and the frontal regions," explains Sergio. "The impairments observed in the participants at increased risk of Alzheimer's disease may reflect inherent brain alteration or early neuropathology, which is disrupting reciprocal brain communication between hippocampal, parietal and frontal brain regions."

"In terms of being able to categorize the low Alzheimer's disease risk and the high Alzheimer's disease risk, we were able to do that quite well using these kinematic measures," says Hawkins. "This group had slower reaction time and movement time, as well as less accuracy and precision in their movements."

Hawkins says the findings don't predict who will develop Alzheimer's disease, but they do show there is something different in the brains of most of the participants diagnosed with MCI or who had a family history of the disease.


Story Source:

The above story is based on materials provided by York University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lauren Sergio et al. Visuomotor Impairments in Older Adults at Increased Alzheimer’s Disease Risk. Journal of Alzheimer's Disease, September 2014 DOI: 10.3233/JAD-140051

Knowledge or entertainment: Which would you pay for?

 

From firewalls to metered access, news organisations have invented many ways to make readers pay for their content online. But the vital question of which readers are more willing to pay than others has been largely neglected -- until now.

Over 500 American adults were asked what factors affect their willingness to pay in a study by Manuel Goyanes, from the Universidad Carlos III de Madrid. Before revealing his results in the current issue of Journalism Practice, Goyanes explains just what the paid online news model is up against, stating that "[This] study shows that online users were more likely to pay for those digital products whose main value proposition consists of providing entertainment (music) and solutions (software and apps), but less likely to pay for those providing knowledge (such as an online newspaper)."

Ultimately, Goyanes found that younger and wealthier users were more likely to be willing to pay for online news, as were moderate users of Twitter; heavy Twitter users were more likely to buy into the "culture of free." People who've bought software programmes, online movies, apps or ebooks are also more likely to pay for online news; in other words, users who pay for entertainment on their devices are more likely to pay for information as well.

But for ailing newspapers, identifying and understanding the needs of which users are more likely to pay is only half the problem. What to offer them based on this knowledge is the other, and Goyanes makes a startling recommendation: "It is now time for online news organisations to develop new partnerships or strategic alliances with entertainment companies with the aim of creating and sharing new (complementary) services based on leisure, culture, entertainment, etc." To survive, "online news organisations need to go a step beyond the classical production of information when implementing paid content strategies."

Goyanes' research shows that younger readers should be foremost in these strategies: "Despite the constant decline of young readers in the traditional newspaper industry, the internet presents a great opportunity for media managers to attract and convince them, since it is the market segment that is more likely to pay for information."

This article is essential reading for anyone involved in either online or traditional news media, as it illustrates the on-going effects of the digital revolution on the creation, distribution and consumption of news.

Gene responsible for traits involved in diabetes discovered

 


A collaborative research team led by Medical College of Wisconsin (MCW) scientists has identified a new gene associated with fasting glucose and insulin levels in rats, mice and in humans. The findings are published in the September issue of Genetics.

Leah Solberg Woods, Ph.D., associate professor of pediatrics at MCW and a researcher in the Children's Hospital of Wisconsin Research Institute, led the study and is the corresponding author of the paper.

The authors of the paper identified a gene called Tpcn2 in which a variant was associated with fasting glucose levels in a rat model. Studies in Tpcn2 knockout mice also demonstrated the difference in fasting glucose levels as well as insulin response between the knockout animals and regular mice. Finally, Dr. Woods' team identified variants within Tpcn2 associated with fasting insulin in humans. Tpcn2 is a lysosomal calcium channel that likely plays a role in insulin signaling. Glucose tolerance, insulin resistance and beta cell dysfunction are key underlying causes of type 2 diabetes.

"Genome-wide association studies in humans have identified 60+ genes linked to type 2 diabetes; however, these genes explain only a small portion of heritability in diabetes studies. As we continue to identify genes and variants of interest, we will evaluate them in multiple models to understand the mechanism of disease," said Dr. Solberg Woods.

According to the American Diabetes Association, 29 million Americans have diabetes -- more than nine percent of the total population. It is the 7th leading cause of death, and experts estimate diabetes is an underreported cause of death because of the comorbidities and complications associated with the disease.


Story Source:

The above story is based on materials provided by Medical College of Wisconsin. Note: Materials may be edited for content and length.


Journal Reference:

  1. S.-W. Tsaih, K. Holl, S. Jia, M. Kaldunski, M. Tschannen, H. He, J. W. Andrae, S.-H. Li, A. Stoddard, A. Wiederhold, J. Parrington, M. Ruas da Silva, A. Galione, J. Meigs, R. G. Hoffmann, P. Simpson, H. Jacob, M. Hessner, L. C. Solberg Woods. Identification of a Novel Gene for Diabetic Traits in Rats, Mice, and Humans. Genetics, 2014; 198 (1): 17 DOI: 10.1534/genetics.114.162982

Psychosocial Development in Infancy and Early Childhood

 

By Kendra Cherry

Erik Erikson proposed a theory of psychosocial development that looked at development through the whole lifespan.

What is Psychosocial Development?

Erik Erikson's theory of psychosocial development is one of the best-known theories of personality in psychology. Much like Sigmund Freud, Erikson believed that personality develops in a series of stages. Unlike Freud's theory of psychosexual stages, Erikson's theory describes the impact of social experience across the whole lifespan.

One of the main elements of Erikson's psychosocial stage theory is the development of ego identity. Ego identity is the conscious sense of self that we develop through social interaction. According to Erikson, our ego identity is constantly changing due to new experiences and information we acquire in our daily interactions with others.

When psychologists talk about identity, they are referring to all of the beliefs, ideals, and values that help shape and guide a person's behavior. The formation of identity is something that begins in childhood and becomes particularly important during adolescence, but it is a process that continues throughout life.Our personal identity gives each of us an integrated and cohesive sense of self that endures and continues to grow as we age.

In addition to ego identity, Erikson also believed that a sense of competence motivates behaviors and actions. Each stage in Erikson's theory is concerned with becoming competent in an area of life. If the stage is handled well, the person will feel a sense of mastery, which is sometimes referred to as ego strength or ego quality. If the stage is managed poorly, the person will emerge with a sense of inadequacy.

In each stage, Erikson believed people experience a conflict that serves as a turning point in development. In Erikson's view, these conflicts are centered on either developing a psychological quality or failing to develop that quality.During these times, the potential for personal growth is high, but so is the potential for failure.

Psychosocial Stage 1 - Trust vs. Mistrust
  • The first stage of Erikson's theory of psychosocial development occurs between birth and one year of age and is the most fundamental stage in life.
  • Because an infant is utterly dependent, the development of trust is based on the dependability and quality of the child's caregivers.
  • If a child successfully develops trust, he or she will feel safe and secure in the world. Caregivers who are inconsistent, emotionally unavailable, or rejecting contribute to feelings of mistrust in the children they care for. Failure to develop trust will result in fear and a belief that the world is inconsistent and unpredictable.
  • Of course, no child is going to develop a sense of 100 percent trust or 100 percent doubt. Erikson believed that successful development was all about striking a balance between the two opposing sides. When this happens, children acquire hope, which Erikson described as an openness to experience tempered by some wariness that danger may be present.
Psychosocial Stage 2 - Autonomy vs. Shame and Doubt
  • The second stage of Erikson's theory of psychosocial development takes place during early childhood and is focused on children developing a greater sense of personal control.2
  • Like Freud, Erikson believed that toilet training was a vital part of this process. However, Erikson's reasoning was quite different then that of Freud's. Erikson believe that learning to control one's bodily functions leads to a feeling of control and a sense of independence.
  • Other important events include gaining more control over food choices, toy preferences, and clothing selection.
  • Children who successfully complete this stage feel secure and confident, while those who do not are left with a sense of inadequacy and self-doubt.
  • Erikson believed that achieving a balance between autonomy and shame and doubt would lead to will, which is the belief that children can act with intention, within reason and limits.

Psychosocial Stage 3 – Initiative vs Guilty

During the preschool years, children begin to assert their power and control over the world through directing play and other social interactions.

  • Children who are successful at this stage feel capable and able to lead others.Those who fail to acquire these skills are left with a sense of guilt, self-doubt, and lack of initiative.
  • When an ideal balance of individual initiative and a willingness to work with others is achieved, the ego quality known as purpose emerges.
Psychosocial Stage 4 - Industry vs. Inferiority
  • This stage covers the early school years from approximately age 5 to 11.
  • Through social interactions, children begin to develop a sense of pride in their accomplishments and abilities.
  • Children who are encouraged and commended by parents and teachers develop a feeling of competence and belief in their skills. Those who receive little or no encouragement from parents, teachers, or peers will doubt their abilities to be successful.
  • Successfully finding a balance at this stage of psychosocial development leads to the strength known as competence or a belief our own abilities to handle the tasks set before us.
Psychosocial Stage 5 - Identity vs. Confusion
  • During adolescence, children explore their independence and develop a sense of self.
  • Those who receive proper encouragement and reinforcement through personal exploration will emerge from this stage with a strong sense of self and a feeling of independence and control. Those who remain unsure of their beliefs and desires will feel insecure and confused about themselves and the future.
  • Completing this stage successfully leads to fidelity, which Erikson described as an ability to live by society's standards and expectations.

Psychosocial Stage 6 – Intimatcy vc Isolation

  • This stage covers the period of early adulthood when people are exploring personal relationships.
  • Erikson believed it was vital that people develop close, committed relationships with other people. Those who are successful at this step will form relationships that are committed and secure.
  • Remember that each step builds on skills learned in previous steps. Erikson believed that a strong sense of personal identity was important for developing intimate relationships. Studies have demonstrated that those with a poor sense of self tend to have less committed relationships and are more likely to suffer emotional isolation, loneliness , and depression.
  • Successful resolution of this stage results in the virtue known as love. It is marked by the ability to form lasting, meaningful relationships with other people.
Psychosocial Stage 7 - Generativity vs. Stagnation
  • During adulthood, we continue to build our lives, focusing on our career and family.
  • Those who are successful during this phase will feel that they are contributing to the world by being active in their home and community.Those who fail to attain this skill will feel unproductive and uninvolved in the world.
  • Care is the virtue achieved when this stage is handled successfully. Being proud of your accomplishments, watching your children grow into adults, and developing a sense of unity with your life partner are important accomplishments of this stage.
Psychosocial Stage 8 - Integrity vs. Despair
  • This phase occurs during old age and is focused on reflecting back on life.
  • Those who are unsuccessful during this stage will feel that their life has been wasted and will experience many regrets. The individual will be left with feelings of bitterness and despair.
  • Those who feel proud of their accomplishments will feel a sense of integrity.Successfully completing this phase means looking back with few regrets and a general feeling of satisfaction. These individuals will attain wisdom, even when confronting death.
More About Erikson and Psychosocial Stages
The Strengths of Erikson's Theory

One of the strengths of psychosocial theory is that it provides a broad framework from which to view development throughout the entire lifespan. It also allows us to emphasize the social nature of human beings and the important influence that social relationships have on development. Researchers have found evidence supporting Erikson's ideas about identity and have further identified different sub-stages of identity formation. Some research also suggests that people who form strong personal identities during adolescence are better capable of forming intimate relationships during early adulthood.

Limitations of Psychosocial Theory

What kinds of experiences are necessary to successfully complete each stage?How does a person move from one stage to the next? One major weakness of psychosocial theory is that the exact mechanisms for resolving conflicts and moving from one stage to the next are not well described or developed. The theory fails to detail exactly what type of experiences are necessary at each stage in order to successfully resolve the conflicts and move to the next stage.

Pathway that contributes to Alzheimer's disease revealed by research

 


Loss of LRP6 in neurons leads to enhanced buildup of amyloid protein, a pathological hallmark of Alzheimer's disease.

Researchers at Jacksonville's campus of Mayo Clinic have discovered a defect in a key cell-signaling pathway they say contributes to both overproduction of toxic protein in the brains of Alzheimer's disease patients as well as loss of communication between neurons -- both significant contributors to this type of dementia.

Their study, in the online issue of Neuron, offers the potential that targeting this specific defect with drugs "may rejuvenate or rescue this pathway," says the study's lead investigator, Guojun Bu, Ph.D., a neuroscientist at Mayo Clinic, Jacksonville, Fla.

"This defect is likely not the sole contributor to development of Alzheimer's disease, but our findings suggest it is very important, and could be therapeutically targeted to possibly prevent Alzheimer's or treat early disease," he says.

The pathway, Wnt signaling, is known to play a critical role in cell survival, embryonic development and synaptic activity -- the electrical and chemical signals necessary for learning and memory. Any imbalance in this pathway (too much or too little activity) leads to disease -- the overgrowth of cells in cancer is one example of overactivation of this pathway.

While much research on Wnt has focused on diseases involved in overactive Wnt signaling, Dr. Bu's team is one of the first to demonstrate the link between suppressed Wnt signaling and Alzheimer's disease.

"Our finding makes sense, because researchers have long known that patients with cancer are at reduced risk of developing Alzheimer's disease, and vice versa," Dr. Bu says. "What wasn't known is that Wnt signaling was involved in that dichotomy."

Using a new mouse model, the investigators discovered the key defect that leads to suppressed Wnt signaling in Alzheimer's. They found that the low-density lipoprotein receptor-related protein 6 (LRP6) is deficient, and that LRP6 regulates both production of amyloid beta, the protein that builds up in the brains of AD patients, and communication between neurons. That means lower than normal levels of LRP6 leads to a toxic buildup of amyloid and impairs the ability of neurons to talk to each other.

Mice without LRP6 had impaired Wnt signaling, cognitive impairment, neuroinflammation and excess amyloid.

The researchers validated their findings by examining postmortem brain tissue from Alzheimer's patients -- they found that LRP6 levels were deficient and Wnt signaling was severely compromised in the human brain they examined.

The good news is that specific inhibitors of this pathway are already being tested for cancer treatment. "Of course, we don't want to inhibit Wnt in people with Alzheimer's or at risk for the disease, but it may be possible to use the science invested in inhibiting Wnt to figure out how to boost activity in the pathway," Dr. Bu says.

"Identifying small molecule compounds to restore LRP6 and the Wnt pathway, without inducing side effects, may help prevent or treat Alzheimer's disease," he says. "This is a really exciting new strategy -- a new and fresh approach."


Story Source:

The above story is based on materials provided by Mayo Clinic. The original article was written by Kevin Punsky. Note: Materials may be edited for content and length.


Journal Reference:

  1. Chia-Chen Liu, Chih-Wei Tsai, Ferenc Deak, Justin Rogers, Michael Penuliar, You Me Sung, James N. Maher, Yuan Fu, Xia Li, Huaxi Xu, Steven Estus, Hyang-Sook Hoe, John D. Fryer, Takahisa Kanekiyo, Guojun Bu. Deficiency in LRP6-Mediated Wnt Signaling Contributes to Synaptic Abnormalities and Amyloid Pathology in Alzheimer’s Disease. Neuron, 2014; DOI: 10.1016/j.neuron.2014.08.048

Possible 6,800 new Ebola cases this month, research predicts

 


New research published today in the online journal PLoS Outbreaks predicts new Ebola cases could reach 6,800 in West Africa by the end of the month if new control measures are not enacted.

Arizona State University and Harvard University researchers also discovered through modelling analysis that the rate of rise in cases significantly increased in August in Liberia and Guinea, around the time that a mass quarantine was put in place, indicating that the mass quarantine efforts may have made the outbreak worse than it would have been otherwise. Deteriorating living and hygiene conditions in some of the quarantined areas sparked riots last month. Sierra Leone began a three day country-wide quarantine today, where all citizens have been asked to stay at home, said Sherry Towers, research professor for the ASU Simon A. Levin Mathematical, Computational and Modelling Sciences Center (MCMSC).

"There may be other reasons for the worsening of the outbreak spread, including the possibility that the virus has become more transmissible, but it's also possible that the quarantine control efforts actually made the outbreak spread more quickly by crowding people together in unsanitary conditions," Towers said.

The study, "Temporal variations in the effective reproduction number of the 2014 West Africa Ebola outbreak," is authored by Towers, Oscar Patterson-Lomba of the Harvard School of Public Health and Carlos Castillo-Chavez, ASU Regent's professor and MCMSC executive director.

Researchers assessed whether or not attempted control efforts are effective in curbing the ongoing West African Ebola outbreak that has spread over a large geographic area, causing thousands of infections and deaths. Because the outbreak has spread to densely populated areas, the risk of international spread is increased. Also compounding the problem is a lack of resources for effective quarantine and isolation in the under-developed countries that have been affected, and the high mobility of the population in a region with porous borders, according to the study.

"No licensed vaccine or specific treatment for the disease is currently available. This leaves improved hygiene, quarantine, isolation and social distancing as the only potential interventions," Castillo-Chavez said. "Improved control measures must be put into place." On Tuesday, President Obama announced that 3,000 US troops and medical personnel would be sent to the region to help control the outbreak, he added.

Researchers examined the current outbreak data for Guinea, Sierra Leone and Liberia through statistical research methods up until Sept. 8, 2014, as estimated by the World Health Organization. The analysis examines the local rates of exponential rise to estimate how the reproduction number of cases appears to be changing over time. Calculations showed a range of 6,800 predicted new cases at the upper end of the spectrum and 4,400 on average. The study was funded by the National Institute of General Medical Sciences at the National Institutes of Health.

Further information can be found at: http://currents.plos.org/outbreaks/article/temporal-variations-in-the-effective-reproduction-number-of-the-2014-west-africa-ebola-outbreak/


Story Source:

The above story is based on materials provided by Arizona State University. Note: Materials may be edited for content and length.

Solar-cell efficiency improved with new polymer devices

 

September 19, 2014

University of Chicago

New light has been shed on solar power generation using devices made with polymers. Researchers identified a new polymer -- a type of large molecule that forms plastics and other familiar materials -- which improved the efficiency of solar cells. The group also determined the method by which the polymer improved the cells' efficiency. The polymer allowed electrical charges to move more easily throughout the cell, boosting the production of electricity -- a mechanism never before demonstrated in such devices.


This polymer solar cell consists of a new polymer, called PID2, which was developed in the laboratory of Luping Yu, professor in chemistry at the University of Chicago. The new polymer improves the efficiency of electrical power generation by 15 percent when added to a standard polymer-fullerene mixture.

New light has been shed on solar power generation using devices made with polymers, thanks to a collaboration between scientists in the University of Chicago's chemistry department, the Institute for Molecular Engineering, and Argonne National Laboratory.

Researchers identified a new polymer -- a type of large molecule that forms plastics and other familiar materials -- which improved the efficiency of solar cells. The group also determined the method by which the polymer improved the cells' efficiency. The polymer allowed electrical charges to move more easily throughout the cell, boosting the production of electricity -- a mechanism never before demonstrated in such devices.

"Polymer solar cells have great potential to provide low-cost, lightweight and flexible electronic devices to harvest solar energy," said Luyao Lu, graduate student in chemistry and lead author of a paper describing the result, published online last month in the journal Nature Photonics.

Solar cells made from polymers are a popular topic of research due to their appealing properties. But researchers are still struggling to efficiently generate electrical power with these materials.

"The field is rather immature -- it's in the infancy stage," said Luping Yu, professor in chemistry, fellow in the Institute for Molecular Engineering, who led the UChicago group carrying out the research.

The active regions of such solar cells are composed of a mixture of polymers that give and receive electrons to generate electrical current when exposed to light. The new polymer developed by Yu's group, called PID2, improves the efficiency of electrical power generation by 15 percent when added to a standard polymer-fullerene mixture.

"Fullerene, a small carbon molecule, is one of the standard materials used in polymer solar cells," Lu said. "Basically, in polymer solar cells we have a polymer as electron donor and fullerene as electron acceptor to allow charge separation." In their work, the UChicago-Argonne researchers added another polymer into the device, resulting in solar cells with two polymers and one fullerene.

8.2 percent efficiency

The group achieved an efficiency of 8.2 percent when an optimal amount of PID2 was added -- the highest ever for solar cells made up of two types of polymers with fullerene -- and the result implies that even higher efficiencies could be possible with further work. The group is now working to push efficiencies toward 10 percent, a benchmark necessary for polymer solar cells to be viable for commercial application.

The result was remarkable not only because of the advance in technical capabilities, Yu noted, but also because PID2 enhanced the efficiency via a new method. The standard mechanism for improving efficiency with a third polymer is by increasing the absorption of light in the device. But in addition to that effect, the team found that when PID2 was added, charges were transported more easily between polymers and throughout the cell.

In order for a current to be generated by the solar cell, electrons must be transferred from polymer to fullerene within the device. But the difference between electron energy levels for the standard polymer-fullerene is large enough that electron transfer between them is difficult. PID2 has energy levels in between the other two, and acts as an intermediary in the process.

"It's like a step," Yu said. "When it's too high, it's hard to climb up, but if you put in the middle another step then you can easily walk up."

Thanks to a collaboration with Argonne, Yu and his group were also able to study the changes in structure of the polymer blend when PID2 was added, and show that these changes likewise improved the ability of charges to move throughout the cell, further improving the efficiency. The addition of PID2 caused the polymer blend to form fibers, which improve the mobility of electrons throughout the material. The fibers serve as a pathway to allow electrons to travel to the electrodes on the sides of the solar cell.

"It's like you're generating a street and somebody that's traveling along the street can find a way to go from this end to another," Yu said.

To reveal this structure, Wei Chen of the Materials Science Division at Argonne National Laboratory and the Institute for Molecular Engineering performed X-ray scattering studies using the Advanced Photon Source at Argonne and the Advanced Light Source at Lawrence Berkeley.

"Without that it's hard to get insight about the structure," Yu said, calling the collaboration with Argonne "crucial" to the work. "That benefits us tremendously," he said.

Chen noted that "Working together, these groups represent a confluence of the best materials and the best expertise and tools to study them to achieve progress beyond what could be achieved with independent efforts.

"This knowledge will serve as a foundation from which to develop high-efficiency organic photovoltaic devices to meet the nation's future energy needs," Chen said. -- By Emily Conover


Story Source:

The above story is based on materials provided by University of Chicago. Note: Materials may be edited for content and length.


Journal Reference:

  1. Luyao Lu, Tao Xu, Wei Chen, Erik S. Landry, Luping Yu. Ternary blend polymer solar cells with enhanced power conversion efficiency. Nature Photonics, 2014; 8 (9): 716 DOI: 10.1038/nphoton.2014.172

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