Why breastfed babies are so smart: Moms who breastfeed are often responsive and read to their babies

Loads of studies over the years have shown that children who were breastfed score higher on IQ tests and perform better in school, but the reason why remained unclear.Is it the mother-baby bonding time, something in the milk itself or some unseen attribute of mothers who breastfeed their babies?Now a new study by sociologists at Brigham Young University pinpoints two parenting skills as the real source of this cognitive boost: Responding to children’s emotional cues and reading to children starting at 9 months of age. Breastfeeding mothers tend to do both of those things, said lead study author Ben Gibbs.”It’s really the parenting that makes the difference,” said Gibbs. “Breastfeeding matters in others ways, but this actually gives us a better mechanism and can shape our confidence about interventions that promote school readiness.”Gibbs authored the study with fellow BYU professor Renata Forste for the March issue of The Journal of Pediatrics. According to their analysis, improvements in sensitivity to emotional cues and time reading to children could yield 2-3 months’ worth of brain development by age 4 (as measured by math and reading readiness assessments).”Because these are four-year-olds, a month or two represents a non-trivial chunk of time,” Gibbs said. “And if a child is on the edge of needing special education, even a small boost across some eligibility line could shape a child’s educational trajectory.”The BYU scholars utilized a national data set that followed 7,500 mothers and their children from birth to five years of age. The data set is rich with information on the home environment, including how early and how often parents read to their kids. Additionally, each of the mothers in the study also participated in video-taped activities with their children. As the child tried to complete a challenging task, the mother’s supportiveness and sensitivity to their child’s emotional cues were measured.The study gained editorial praise from child development expert Sandra Jacobson of Wayne State University School of Medicine. She noted that children in the study who were breastfed for 6 months or longer performed the best on reading assessments because they also “experienced the most optimal parenting practices.”Gibbs and Forste found that reading to an infant every day as early as age 9 months and sensitivity to the child’s cues during social interactions, rather than breastfeeding per se, were significant predictors of reading readiness at age 4 years,” wrote Jacobson.The BYU researchers note that the most at-risk children are also the least likely to receive the optimal parenting in early childhood. Single moms in the labor force, for example, don’t have the same luxuries when it comes to breastfeeding and quality time with the children. …

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Cavities are contagious, research shows

Dental caries, commonly known as tooth decay, is the single most common chronic childhood disease. In fact, it is an infectious disease. Mothers with cavities can transmit caries-producing oral bacteria to their babies when they clean pacifiers by sticking them in their own mouths or by sharing spoons.According to Liliana Rozo, D.D.S., assistant profesor, University of Louisville School of Dentistry, tooth decay can have a detrimental effect on a child’s quality of life, performance in school and success in life. The disease can cause pain, inability to chew food well, embarrassment about discolored or damaged teeth, and distraction from play and learning.The American Academy of Pediatric Dentistry (AAPD) encourages parents to find a dental home for their baby as soon as the child’s first tooth erupts. Regular visits to a pediatric dentist will help parents become familiar with their child’s dental and oral health milestones. They’ll inform parents about teething, proper oral hygiene habits, normal tooth development, and trauma prevention. Nutritional counseling also will be a part of the discussion.Often, Rozo said, parents do not make the connection between oral health and overall health, but they are related. The mouth is an open door for many microbial infections to enter the bloodstream. Poor oral health may be a risk factor for systemic disease. Oral health manifestations, such as bleeding or dry mouth can indicate the presence of a systemic disease or exacerbate the effects of an existing disease such as diabetes and heart disease.So parents, too, should make their own oral health care a priority in order to help their children stay healthy, said Rozo, an AAPD board certified pediatric dentist.Story Source:The above story is based on materials provided by University of Louisville. …

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New RNA interference technique finds seven genes for head and neck cancer

In the hunt for genetic mutations that cause cancer, there is a lot of white noise. So although genetic sequencing has identified hundreds of genetic alterations linked to tumors, it’s still an enormous challenge to figure out which ones are actually responsible for the growth and metastasis of cancer. Scientists in Rockefeller’s Laboratory of Mammalian Cell Biology and Development have created a new technique that can weed out that noise — eliminating the random bystander genes and identifying the ones that are critical for cancer. Applying their technique to head and neck cancers, they’ve discovered seven new tumor-suppressor genes whose role in cancer was previously unknown.The new technique, which the lab recently applied to a screen for skin tumor genes, is particularly useful because it takes a fraction of the resources and much less time than the traditional method for determining gene function — breeding genetically modified animals to study the impact of missing genes.”Using knockout mice, which are model organisms bred to have a particular gene missing, is not feasible when there are 800 potential head and neck cancer genes to sort through,” says Daniel Schramek, a postdoctoral fellow in the lab, which is headed by Rebecca C. Lancefield Professor Elaine Fuchs. “It can take about two years per gene. Our method can assess about 300 genes in a single mouse, in as little as five weeks.”The researchers made use of RNA interference, a natural process whereby RNA molecules inhibit gene expression. They took short pieces of RNA which are able to turn off the function of specific genes, attached them to highly concentrated viruses, and then, using ultrasound to guide the needle without damaging surrounding tissue, they injected the viruses into the sacs of mouse embryos.”The virus is absorbed and integrated into the chromosomes of the single layer of surface cells that cover the tiny embryo,” explains Fuchs. “As the embryo develops, this layer of cells becomes the skin, mammary glands and oral tissue, enabling us to efficiently, selectively and quickly eliminate the expression of any desired gene in these tissues. The non-invasive method avoids triggering a wound or inflammatory response that is typically associated with conventional methods to knockdown a gene in cultured cells and then engraft the cells onto a mouse.”When the mice grew, the researchers determined which genes, when turned off, were promoting tumor growth, and what they found was surprising.”Among the seven novel tumor suppressor genes we found, our strongest hit was Myh9, which codes for the protein myosin IIa, a motor protein with well-known function in cell structure and cell migration,” says Schramek. …

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Helping preserve independent living for seniors

Single seniors lead a risky life: after a fall, they often lie on the floor several hours before their awkward predicament is discovered. A sensor system detects these emergency situations automatically and sends an emergency signal.Mr. S. is visually impaired and dependent on a cane since suffering a stroke. Nevertheless, as a 70-yr old living alone, he would rather not move into a care home. Most older people harbor this wish. They want to stay in their own familiar surroundings and continue to live independently for as long as possible. According to data from the German Federal Statistical Office, this applies to 70 percent of seniors. Against better judgment, they are putting their health at risk, for not only does the risk of cardiovascular problems increase with age, but the risk of falling increases also. According to estimates, about 30 percent of those over 65 years of age living at home experience a fall at least once a year. …

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Breakthrough in rechargeable batteries: New twist to sodium-ion battery technology

A Kansas State University engineer has made a breakthrough in rechargeable battery applications.Gurpreet Singh, assistant professor of mechanical and nuclear engineering, and his student researchers are the first to demonstrate that a composite paper — made of interleaved molybdenum disulfide and graphene nanosheets — can be both an active material to efficiently store sodium atoms and a flexible current collector. The newly developed composite paper can be used as a negative electrode in sodium-ion batteries.”Most negative electrodes for sodium-ion batteries use materials that undergo an ‘alloying’ reaction with sodium,” Singh said. “These materials can swell as much as 400 to 500 percent as the battery is charged and discharged, which may result in mechanical damage and loss of electrical contact with the current collector.””Molybdenum disulfide, the major constituent of the paper electrode, offers a new kind of chemistry with sodium ions, which is a combination of intercalation and a conversion-type reaction,” Singh said. “The paper electrode offers stable charge capacity of 230 mAh.g-1, with respect to total electrode weight. Further, the interleaved and porous structure of the paper electrode offers smooth channels for sodium to diffuse in and out as the cell is charged and discharged quickly. This design also eliminates the polymeric binders and copper current collector foil used in a traditional battery electrode.”The research appears in the latest issue of the journal ACS Nanoin the article “MoS2/graphene composite paper for sodium-ion battery electrodes.”For the last two years the researchers have been developing new methods for quick and cost-effective synthesis of atomically thin two-dimensional materials — graphene, molybdenum and tungsten disulfide — in gram quantities, particularly for rechargeable battery applications.For the latest research, the engineers created a large-area composite paper that consisted of acid-treated layered molybdenum disulfide and chemically modified graphene in an interleaved structured. The research marks the first time that such a flexible paper electrode was used in a sodium-ion battery as an anode that operates at room temperature. Most commercial sodium-sulfur batteries operate close to 300 degrees Celsius, Singh said.Singh said the research is important for two reasons:1. Synthesis of large quantities of single or few-layer-thick 2-D materials is crucial to understanding the true commercial potential of materials such as transition metal dichalcogenides, or TMD, and graphene.2. Fundamental understanding of how sodium is stored in a layered material through mechanisms other than the conventional intercalation and alloying reaction. …

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Your eyes may hold clues to stroke risk

Aug. 12, 2013 — Photographing the retina may help detect which high blood pressure patients are more likely to have a stroke. Retinal imaging may be an inexpensive and non-invasive way to assess risk.Your eyes may be a window to your stroke risk.In a study reported in the American Heart Association journal Hypertension, researchers said retinal imaging may someday help assess if you’re more likely to develop a stroke — the nation’s No. 4 killer and a leading cause of disability.”The retina provides information on the status of blood vessels in the brain,” said Mohammad Kamran Ikram, M.D., Ph.D., lead author of the study and assistant professor in the Singapore Eye Research Institute, the Department of Ophthalmology and Memory Aging & Cognition Centre, at the National University of Singapore. “Retinal imaging is a non-invasive and cheap way of examining the blood vessels of the retina.”Worldwide, high blood pressure is the single most important risk factor for stroke. However, it’s still not possible to predict which high blood pressure patients are most likely to develop a stroke.Researchers tracked stroke occurrence for an average 13 years in 2,907 patients with high blood pressure who had not previously experienced a stroke. At baseline, each had photographs taken of the retina, the light-sensitive layer of cells at the back of the eyeball. Damage to the retinal blood vessels attributed to hypertension — called hypertensive retinopathy — evident on the photographs was scored as none, mild or moderate/severe.During the follow-up, 146 participants experienced a stroke caused by a blood clot and 15 by bleeding in the brain.Researchers adjusted for several stroke risk factors such as age, sex, race, cholesterol levels, blood sugar, body mass index, smoking and blood pressure readings. They found the risk of stroke was 35 percent higher in those with mild hypertensive retinopathy and 137 percent higher in those with moderate or severe hypertensive retinopathy.Even in patients on medication and achieving good blood pressure control, the risk of a blood clot was 96 percent higher in those with mild hypertensive retinopathy and 198 percent higher in those with moderate or severe hypertensive retinopathy.”It is too early to recommend changes in clinical practice,” Ikram said. “Other studies need to confirm our findings and examine whether retinal imaging can be useful in providing additional information about stroke risk in people with high blood pressure.”

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Children and magnets have a dangerous attraction, end up in the ER

Aug. 7, 2013 — Cases involving children ingesting magnets quintupled between 2002 and 2011, with ingestion of multiple magnets generally resulting in more serious outcomes, including emergency surgery. The results of a study documenting a rapid rise in pediatric injuries was published online yesterday in Annals of Emergency Medicine.”It is common for children to put things in their mouth and nose, but the risk of intestinal damage increases dramatically when multiple magnets are swallowed,” said lead study author Jonathan Silverman, MD, of the Department of Pediatrics at the University of Washington in Seattle, Wash. “The ingestion of multiple magnets can severely damage intestinal walls to the point that some kids need surgery. The magnets in question were typically those found in kitchen gadgets or desk toys marketed to adults but irresistible to children.”Over a 10-year period, 22,581 magnetic foreign body injuries were reported among children. Between 2002 and 2003, incidence of injury was 0.57 cases per 100,000 children; between 2010 and 2011, that jumped to 3.06 cases per year out of 100,000 children. The majority of the cases occurred in 2007 or later.In cases where children ingested multiple magnets, 15.7 percent were admitted to the hospital (versus 2.3 percent of single magnet ingestions). Nearly three-quarters (74 percent) of magnets were swallowed; twenty-one percent were ingested through the nose. Nearly one-quarter (23.4 percent) of the case reports described the magnets as “tiny,” or other variants on the word “small.””The injuries were not restricted to small children either,” said Dr. Silverman. …

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Often misidentified, multiracial people value accurate perceptions

Aug. 4, 2013 — Multiracial people may be misidentified more often as being white than black and may value being accurately identified more so than single-race individuals, according to research presented at APA’s 121st Annual Convention.”Today, the distinctions among white, black, Latino and Asian people are becoming blurred by the increasing frequency and prominence of multiracial people,” said Jacqueline M. Chen, PhD, of the University of California, Davis. “Still, average Americans have difficulty identifying multiracial people who don’t conform to the traditional single-race categories that society has used all their lives.”Chen discussed six experiments in which participants were consistently less likely to identify people as multiracial than single-race and took longer to identify someone as multiracial compared to how easily they identified black, white and Asian people. When they made incorrect identifications, they were consistently more likely to categorize a multiracial person as white than black, the study found. Time pressure, distractions and thinking of race in either-or terms made observers significantly less likely to identify someone as multiracial. The study was conducted at the University of California, Santa Barbara and involved 435 ethnically diverse undergraduate students.Participants identified the race of black, white, Asian or multiracial individuals in photos and researchers recorded each participant’s accuracy and time to respond. Researchers used a memorization task and a time limit in two experiments to determine if either would affect a participant’s accuracy. In another experiment, participants were told the study was about reading comprehension and attention. They then read news articles about scientists claiming to find a genetic basis for race and were asked to view several photographs of faces and identify them by race.Scientists agree that the racial categories we use today are not based on biological differences but are social constructions that can change over time, Chen said, noting that until the mid-20th century, the Anglo-Saxon majority in the United States viewed Irish and Italian immigrants as different races. …

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Two dimensions of value: Dopamine neurons represent reward but not aversiveness

Aug. 1, 2013 — To make decisions, we need to estimate the value of sensory stimuli and motor actions, their “goodness” and “badness.” We can imagine that good and bad are two ends of a single continuum, or dimension, of value. This would be analogous to the single dimension of light intensity, which ranges from dark on one end to bright light on the other, with many shades of gray in between.Share This:Past models of behavior and learning have been based on a single continuum of value, and it has been proposed that a particular group of neurons (brain cells) that use dopamine as a neurotransmitter (chemical messenger) represent the single dimension of value, signaling both good and bad.The experiments reported here show that dopamine neurons are sensitive to the value of reward but not punishment (like the aversiveness of a bitter taste). This demonstrates that reward and aversiveness are represented as two discrete dimensions (or categories) in the brain. “Reward” refers to the category of good things (food, water, sex, money, etc.), and “punishment” to the category of bad things (stimuli associated with harm to the body and that cause pain or other unpleasant sensations or emotions).Rather than having one neurotransmitter (dopamine) to represent a single dimension of value, the present results imply the existence of four neurotransmitters to represent two dimensions of value. Dopamine signals evidence for reward (“gains”) and some other neurotransmitter presumably signals evidence against reward (“losses”). Likewise, there should be a neurotransmitter for evidence of danger and another for evidence of safety. It is interesting that there are three other neurotransmitters that are analogous to dopamine in many respects (serotonin, norepinephrine, and acetylcholine), and it is possible that they could represent the other three value signals.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by The Korea Advanced Institute of Science and Technology (KAIST), via EurekAlert!, a service of AAAS. Note: Materials may be edited for content and length. For further information, please contact the source cited above. …

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‘Cowcatcher’ enzyme fixes single-strand DNA

July 29, 2013 — Every time one of your cells divides, it exposes its most essential component to great danger: its genome, the sum total of all its genetic information, embodied in the double-stranded helix of DNA. Prior to cell division, this DNA splits into two single strands, each bearing sequences of biochemical bases that form templates for the genomes of the daughter cells. These single strands are particularly vulnerable to assaults by reactive oxygen species — toxic byproducts of respiration — that could cause changes in the genetic information they contain.Left unchecked, such mutations would quickly add up, producing cells riddled with genetic errors — a recipe for DNA-damage linked disorders such as cancer, aging and neurodegenerative diseases. However, through evolution, mammalian cells have developed a way to repair damaged bases in the single-stranded genome. Now University of Texas Medical Branch at Galveston researchers have figured out how this process works, publishing their results this week in the Proceedings of the National Academy of Sciences.To understand the UTMB researchers’ work, it helps to picture DNA strand separation during replication as analogous to the opening of a zipper. As the “zipper” opens, it exposes strings of four uniformly spaced bases attached to each single strand of DNA. Not far behind, each of these strands is straddled by an advancing “replication complex” of proteins busily copying the single strand back into double strand. The single-strand repair problem is located between these new double strands and the opening zipper, where the DNA is most susceptible to damage and removal of a damaged base would cause the strand to break.The UTMB scientists’ work centers on an enzyme called NEIL1, which scientists knew recognized single-stranded DNA and also knew was associated with the replication complex. In a series of in vitro experiments, the researchers determined that NEIL1 actually rides in front of the replication complex, scouting for single-strand DNA damage.”As soon as it encounters the base damage, NEIL1 binds to the damage site and flags it, and replication cannot continue,” said UTMB assistant professor Muralidhar Hegde, the lead author on the paper. “The replication machinery stalls and then regresses, and the two strands come back together which allows repair of the damaged base in duplex DNA, replacing the damaged base with the appropriate normal base.”Then the “DNA zipper” begins opening again.”The replication machinery comes back and it continues,” Hegde said. …

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Neural simulations hint at the origin of brain waves

July 24, 2013 — For almost a century, scientists have been studying brain waves to learn about mental health and the way we think. Yet the way billions of interconnected neurons work together to produce brain waves remains unknown. Now, scientists from EPFL’s Blue Brain Project in Switzerland, at the core of the European Human Brain Project, and the Allen Institute for Brain Science in the United States, show in the July 24th edition of the journal Neuron how a complex computer model is providing a new tool to solve the mystery.The brain is composed of many different types of neurons, each of which carry electrical signals. Electrodes placed on the head or directly in brain tissue allow scientists to monitor the cumulative effect of this electrical activity, called electroencephalography (EEG) signals. But what is it about the structure and function of each and every neuron, and the way they network together, that give rise to these electrical signals measured in a mammalian brain?Modeling Brain CircuitryThe Blue Brain Project is working to model a complete human brain. For the moment, Blue Brain scientists study rodent brain tissue and characterize different types of neurons to excruciating detail, recording their electrical properties, shapes, sizes, and how they connect.To answer the question of brain-wave origin, researchers at EPFL’s Blue Brain Project and the Allen Institute joined forces with the help of the Blue Brain modeling facilities. Their work is based on a computer model of a neural circuit the likes of which have never been seen before, encompassing an unprecedented amount of detail and simulating 12,000 neurons.”It is the first time that a model of this complexity has been used to study the underlying properties of brain waves,” says EPFL scientist Sean Hill.In observing their model, the researchers noticed that the electrical activity swirling through the entire system was reminiscent of brain waves measured in rodents. Because the computer model uses an overwhelming amount of physical, chemical and biological data, the supercomputer simulation allows scientists to analyze brain waves at a level of detail simply unattainable with traditional monitoring of live brain tissue.”We need a computer model because it is impossible to relate the electrical activity of potentially billions of individual neurons and the resulting brain waves at the same time,” says Hill. “Through this view, we’re able to provide an interpretation, at the single-neuron level, of brain waves that are measured when tissue is actually probed in the lab.”Finding brain wave analogsNeurons are somewhat like tiny batteries, needing to be charged in order to fire off an electrical impulse known as a “spike.” It is through these “spikes” that neurons communicate with each other to produce thought and perception. To “recharge” a neuron, charged particles called ions must travel through miniscule ionic channels. …

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Vaccinating boys plays key role in HPV prevention

July 22, 2013 — Improving vaccination rates against the human papillomavirus (HPV) in boys aged 11 to 21 is key to protecting both men and women, says new research from University of Toronto Professor Peter A. Newman from the Factor-Inwentash Faculty of Social Work.HPV has been linked to anal, penile and certain types of throat cancers in men. Since the virus is also responsible for various cancers in women, vaccinating boys will play a crucial role in reducing cancer rates across the sexes.”HPV is the single most common sexually transmitted infection,” says Newman, Canada Research Chair in Health and Social Justice. “But now a vaccine is available that can change that and help to prevent the cancers that sometimes result.”Newman’s research grouped data from 16 separate studies involving more than 5,000 people to analyze rates of HPV vaccine acceptability and examined what factors play a role when determining if young men receive the vaccine.Vaccinations, particularly new ones, can have difficulty gaining traction among the citizens they were developed to help. This problem can be compounded by a lack of information, misinformation and even conspiracy theories about the efficacy and safety of vaccines. Unfortunately, says Newman, misinformation and unfounded vaccine fears can result in cancer deaths that could have been avoided with a simple vaccination.Logistical barriers can also stifle the spread and acceptance of new vaccines. Basic impediments like out-of-pocket cost, transportation to a clinic and wait times for the vaccine can contribute to overall low vaccination rates.The biggest factor affecting male HPV vaccination rates is the lack of a well-established connection linking HPV in men to a life-threatening illness. The correlation between HPV and cervical cancer in women is responsible for popularizing the vaccine among young women. Unfortunately, a similar connection that would motivate males to get the vaccine has not yet been established. That needs to change, says Newman.”The idea of an HPV vaccine for boys is new in Canada and so far it has had a low adoption rate,” says Newman. …

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Single dose of ADHD drug can reduce fall risk in older adults, study suggests

July 17, 2013 — Ben-Gurion University of the Negev (BGU) researchers have discovered that a single dose of methylphenidate (MPH), used to treat Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy, helps to improve balance control during walking, hence reducing the risk of falls among elderly adults.Falls in older adults are the leading cause of hip fractures and other injury-related visits to emergency rooms and of accidental death. Age-related deterioration in gait and balance is a major contributor to falls in older adults.According to a study published in The Journals of Gerontology, the BGU researchers found that a single dose of MPH improves walking by reducing the number of step errors and the step error rate in both single and dual tasks.”Our results add to a growing body of evidence showing that MPH may have a role as a therapeutic option for improving gait and reducing fall risk in older adults,” said Itshak Melzer of BGU’s Schwartz Movement Analysis and Rehabilitation Laboratory, Department of Physical Therapy, Faculty of Health Sciences.”This is especially true in real-life situations, where the requirement to walk commonly occurs under more complicated, ‘dual task’ circumstances with cognitive attention focused elsewhere (e.g., watching traffic, talking) and not on performing a specific motor task.”The study participants were 30 healthy older adults who were at least 70 years-old and had the ability to walk 70 feet (20 meters) without personal assistance or an assistive device. The participants were given a single dose (10 mg.) of MPH and were assessed under four task conditions of single and combined motor and cognitive tasks.”The enhanced attention that comes about as a result of MPH may lead to improved balance control during walking, especially in dual task conditions,” Meltzer explains.”Our findings that MPH improves gait can be explained not just by its effect of attentional improvements, but also by indications that it has a direct influence on areas of the brain that deal with motor and balance control.”

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Exercise rescues mutated neural stem cells

July 5, 2013 — CHARGE syndrome* is a severe developmental disorder affecting multiple organs. It affects 1 in 8500 newborns worldwide. The majority of patients carry a mutation in a gene called CHD7. How this single mutation leads to the broad spectrum of characteristic CHARGE symptoms has been a mystery.CHD7 encodes a so-called chromatin remodeler, an important class of epigenetic regulators. DNA is wound around bead-like nucleosomes consisting of histone proteins. The string of beads is then twisted into a structure called chromatin. The more nucleosomes that occupy a gene, the less active it is. Chromatin remodelers like CHD7 are essential for the regulation of gene activity because they create nucleosome-free regions in the regulatory sequences of genes. Thus, a mutation in a gene coding for a chromatin remodeler may lead to a wide pattern of misregulated genes.Dr. Haikun Liu’s lab at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) is interested in the regulation of adult neural stem cells. …

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Genomes of cholera bacteria from Haiti confirm epidemic originated from single source

July 2, 2013 — The strain of cholera that has sickened thousands in Haiti came from a single source and was not repeatedly introduced to the island over the past three years as some have thought, according to a new study published in mBio®, the online open-access journal of the American Society for Microbiology.The results of this latest study are consistent with earlier findings that indicate Vibrio cholerae bacteria were introduced to Haiti by United nations soldiers between July and October 2010, when Nepalese soldiers arrived to assist recovery efforts after the January 2010 earthquake in that country. The genome sequences of V. cholerae strains from Haiti reveal they have not gained any new genetic material since their introduction and that they have a limited ability to acquire genes from other organisms through a process called transformation.This new information may help public health authorities understand future cholera outbreaks in Haiti and elsewhere, according to the authors. “The use of high resolution sequence data that is amenable to evolutionary analysis will greatly enhance our ability to discern transmission pathways of virulent clones such as the one implicated in this epidemic,” write the authors.The earthquake in January 2010 killed tens of thousands of Haitians, and it was followed several months later by an outbreak of cholera, a disease that had never before been documented in Haiti. Studies of the outbreak indicate that poor sanitation at a United Nations camp resulted in sewage contamination of local water supplies, and phylogenetic analysis of the Haiti V. cholerae strains and strains from around the globe indicate the strain was most likely accidentally brought to the camp by U.N. troops from Nepal.Earlier “fingerprinting” of Haiti’s V. cholerae isolates using pulse-field gel electrophoresis (PFGE) has shown the bacterium has changed somewhat since the epidemic began in October 2010, but because of the nature of PFGE, the significance of those changes was not known. Were the changes meaningful? Were the bacteria gaining or losing genes that could impact the course of disease? …

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Higher education may be protective against multiple sclerosis-associated cognitive deficits

July 2, 2013 — Multiple sclerosis (MS) can lead to severe cognitive impairment as the disease progresses. Researchers in Italy have found that patients with high educational levels show less impairment on a neuropsychological evaluation compared with those with low educational levels.Their results are published in Restorative Neurology and Neuroscience.MS is a progressive immunologic brain disorder with neuropsychological deficits including selective attention, working memory, executive functioning, information processing speed, and long term memory. These deficits often impact daily life (ability to do household tasks, interpersonal relationships, employment, and overall quality of life).In this study, investigators first assessed the role of cognitive reserve, the brain’s active attempt to focus on how tasks are processed, in compensating for the challenge represented by brain damage. Earlier studies had reported that higher cognitive reserve protects MS subjects from disease-related cognitive inefficiency but in these studies cognitive reserve was mainly estimated through a vocabulary test. Here, investigators considered educational level and occupational attainment instead of vocabulary. They also evaluated both educational and occupational experience, hypothesizing that an individual’s lifetime occupational attainment could also be considered a good proxy of CR, similar to the way in which higher occupational attainment reduces the risk of Alzheimer’s disease.The second aim of the study was to investigate the possible role of perceived fatigue. Fatigue can have a great negative influence on daily life, so that higher perceived fatigue might result in lower cognitive performance.Fifty consecutive clinically diagnosed MS patients took part in the study. A control group included 157 clinically healthy subjects, with no psychiatric or neurological diagnosis. Individuals in both groups were, on average, of the same age, education level and gender. The mean age was 40.41 (± 9.67) years, with 12.37 (± 4.42) years of education.Cognitive performance was evaluated using the Paced Auditory Serial Addition Test (PASAT), in which a series of single digit numbers are presented and the two most recent digits must be summed. …

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The Facebook effect: Social media dramatically boosts organ donor registration

June 18, 2013 — A social media push boosted the number of people who registered themselves as organ donors 21-fold in a single day, Johns Hopkins researchers found, suggesting social media might be an effective tool to address the stubborn organ shortage in the United States.The gains were made in May 2012 when the social-networking giant Facebook created a way for users to share their organ donor status with friends and provided easy links to make their status official on state department of motor vehicle websites. The findings are being published in the American Journal of Transplantation.”The short-term response was incredibly dramatic, unlike anything we had ever seen before in campaigns to increase the organ donation rate. And at the end of two weeks, the number of new organ donors was still climbing at twice the normal rate,” says study leader Andrew M. Cameron, M.D., Ph.D., an associate professor of surgery at the Johns Hopkins University School of Medicine. “If we can harness that excitement in the long term, then we can really start to move the needle on the big picture. The need for donor organs vastly outpaces the available supply and this could be a way to change that equation.”Over the last 20 years, despite many efforts, the number of donors has remained relatively static, while the number of people waiting for transplants has increased 10-fold. There are more than 118,000 people currently on waiting lists in the United States for kidneys, livers and other organs and thousands of these patients will die before they receive transplants. It’s estimated that between 5,000 and 10,000 people die every year whose organs would be suitable for transplant, but because they had not consented to be donors, their organs go unused. In the United States, organs may not be removed from a deceased donor without permission from either the individual prior to death or the family at the time of a relative’s death. It is believed that over time, roughly 100 million Americans have registered to donate.By looking at data from Facebook and online motor vehicle registration websites, the researchers found that on May 1, 2012, the day the initiative began, 57,451 Facebook users updated their profiles to share their organ donor status. …

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Particle accelerator that can fit on a tabletop opens new chapter for science research

June 20, 2013 — Physicists at The University of Texas at Austin have built a tabletop particle accelerator that can generate energies and speeds previously reached only by major facilities that are hundreds of meters long and cost hundreds of millions of dollars to build.”We have accelerated about half a billion electrons to 2 gigaelectronvolts over a distance of about 1 inch,” said Mike Downer, professor of physics in the College of Natural Sciences. “Until now that degree of energy and focus has required a conventional accelerator that stretches more than the length of two football fields. It’s a downsizing of a factor of approximately 10,000.”The results, which were published this week in Nature Communications, mark a major milestone in the advance toward the day when multi-gigaelectronvolt (GeV) laser plasma accelerators are standard equipment in research laboratories around the world.Downer said he expects 10 GeV accelerators of a few inches in length to be developed within the next few years, and he believes 20 GeV accelerators of similar size could be developed within a decade.Downer said that the electrons from the current 2 GeV accelerator can be converted into “hard” X-rays as bright as those from large-scale facilities. He believes that with further refinement they could even drive an X-ray free electron laser, the brightest X-ray source currently available to science.A tabletop X-ray laser would be transformative for chemists and biologists, who could use the bright X-rays to study the molecular basis of matter and life with atomic precision, and femtosecond time resolution, without traveling to a large national facility.”The X-rays we’ll be able to produce are of femtosecond duration, which is the time scale on which molecules vibrate and the fastest chemical reactions take place,” said Downer. “They will have the energy and brightness to enable us to see, for example, the atomic structure of single protein molecules in a living sample.”To generate the energetic electrons capable of producing these X-rays, Downer and his colleagues employed an acceleration method known as laser-plasma acceleration. It involves firing a brief but intensely powerful laser pulse into a puff of gas.”To a layman it looks like low technology,” said Downer. “All you do is make a little puff of gas with the right density and profile. The laser pulse comes in. It ionizes that gas and makes the plasma, but it also imprints structure in it. It separates electrons from the ion background and creates these enormous internal space-charge fields. …

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Scientists date prehistoric bacterial invasion still present in today’s plant and animal cells

June 19, 2013 — Long before Earth became lush, when life consisted of single-celled organisms afloat in a planet-wide sea, bacteria invaded the ancient ancestors of plants and animals and took up permanent residence. One bacterium eventually became the mitochondria that today power all plant and animal cells; another became the chloroplast that turns sunlight into energy in green plants.A new analysis by two University of California, Berkeley, graduate students more precisely pinpoints when these life-changing invasions occurred, placing the origin of photosynthesis in plants hundreds of millions of years earlier than once thought.”When you are talking about these really ancient events, scientists have estimated numbers that are all over the board,” said coauthor Patrick Shih. Estimates of the age of eukaryotes — cells with a nucleus that evolved into all of today’s plants and animals — range from 800 million years ago to 3 billion years ago.”We came up with a novel way of decreasing the uncertainty and increasing our confidence in dating these events,” he said. The two researchers believe that their approach can help answer similar questions about the origins of ancient microscopic fossils.Shih and colleague Nicholas Matzke, who will earn their Ph.Ds this summer in plant and microbial biology and integrative biology, respectively, employed fossil and genetic evidence to estimate the dates when bacteria set up shop as symbiotic organisms in the earliest one-celled eukaryotes. They concluded that a proteobacterium invaded eurkaryotes about 1.2 billion years ago, in line withearlier estimates.They found that a cyanobacterium — which had already developed photosynthesis — invaded eukaryotes 900 million years ago, much later than some estimates, which are as high as 2 billion years ago.Previous estimates used hard-to-identify microbial fossilsor ambiguous chemical markers in fossils to estimate the time when bacteria entered ancestral eurkaryotic cells, probably first as parasites and then as symbionts. Shih and Matzke realized that they could get better precision by studying today’s mitochondria and chloroplasts, which from their free-living days still retain genes that are evolutionarily related to genes currently present in plant and animal DNA.”These genes, such as ATP synthase — a gene critical to the synthesis of the energy molecule ATP — were present in our single-celled ancestors and present now, and are really, really conserved,” Matzke said. “These go back to the last common ancestor of all living things, so it helps us constrain the tree of life.”Since mitochrondrial, chloroplast and nuclear genes do not evolve at exactly the same rate, the researchers used Bayesian statistics to estimate the rate variation as well as how long ago the bacteria joined forces with eukaryotes. They improved their precision by focusing on plant and animal fossils that have more certain dates and identities than microbial fossils.The paper appeared online on June 17 in advance of publication in the journal Proceedings of the National Academy of Sciences. Matzke also is a member of UC Berkeley’s Center for Theoretical Evolutionary Genomics.

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2-D electronics take a step forward: Semiconducting films for atom-thick circuits

June 10, 2013 — Scientists at Rice University and Oak Ridge National Laboratory (ORNL) have advanced on the goal of two-dimensional electronics with a method to control the growth of uniform atomic layers of molybdenum disulfide (MDS).MDS, a semiconductor, is one of a trilogy of materials needed to make functioning 2-D electronic components. They may someday be the basis for the manufacture of devices so small they would be invisible to the naked eye.The work appears online this week in Nature Materials.The Rice labs of lead investigator Jun Lou, Pulickel Ajayan and Boris Yakobson, all professors in the university’s Mechanical Engineering and Materials Science Department, collaborated with Wigner Fellow Wu Zhou and staff scientist Juan-Carlos Idrobo at ORNL in an unusual initiative that incorporated experimental and theoretical work.The goals were to see if large, high-quality, atomically thin MDS sheets could be grown in a chemical vapor deposition (CVD) furnace and to analyze their characteristics. The hope is that MDS could be joined with graphene, which has no band gap, and hexagonal boron nitride (hBN), an insulator, to form field-effect transistors, integrated logic circuits, photodetectors and flexible optoelectronics.”For truly atomic circuitry, this is important,” Lou said. “If we get this material to work, then we will have a set of materials to play with for complete, complicated devices.”Last year, Lou and Ajayan revealed their success at making intricate patterns of intertwining graphene and hBN, among them the image of Rice’s owl mascot. But there was still a piece missing for the materials to be full partners in advanced electronic applications. By then, the researchers were already well into their study of MDS as a semiconducting solution.”Two-dimensional materials have taken off,” Ajayan said. “The study of graphene prompted research into a lot of 2-D materials; molybdenum disulfide is just one of them. Essentially, we are trying to span the whole range of band gaps between graphene, which is a semimetal, and the boron nitride insulator.”MDS is distinct from graphene and hBN because it isn’t exactly flat. Graphene and hBN are flat, with arrays of hexagons formed by their constituent atoms. But while MDS looks hexagonal when viewed from above, it is actually a stack, with a layer of molybdenum atoms between two layers of sulfur atoms.Co-author Zheng Liu, a joint research scientist in Lou’s and Ajayan’s labs, noted the Yakobson group predicted that MDS and carbon atoms would bind. …

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