Vitamin deficiency anemia

Vitamin deficiency anemia is a lack of healthy red blood cells caused by lower than normal amounts of certain vitamins. Vitamins linked to vitamin deficiency anemia include folate, vitamin B-12 and vitamin C.

Vitamin deficiency anemia can occur if you don't eat enough folate, vitamin B-12 or vitamin C. Or vitamin deficiency anemia can occur if your body has trouble absorbing or processing these vitamins.

Not all anemias are caused by a vitamin deficiency. Other causes include iron deficiency and certain blood diseases. That's why it's important to have your doctor diagnose and treat your anemia. Vitamin deficiency anemia can usually be corrected with vitamin supplements and changes to your diet.

Signs and symptoms of vitamin deficiency anemia include:

• Fatigue
• Shortness of breath
• Dizziness
• Pale or yellowish skin
• Irregular heartbeats
• Weight loss
• Numbness or tingling in your hands and feet
• Muscle weakness
• Personality changes
• Unsteady movements
• Mental confusion or forgetfulness

Vitamin deficiencies usually develop slowly over several months to years. Vitamin deficiency symptoms may be subtle at first, but they increase as the deficiency worsens.

 

Causes

Vitamin deficiency anemia occurs when your body doesn't have enough of the vitamins needed to produce adequate numbers of healthy red blood cells. Red blood cells carry oxygen from your lungs throughout your body. If your diet is lacking in certain vitamins, vitamin deficiency anemia can develop. Or vitamin deficiency anemia may develop because your body can't properly absorb the nutrients from the foods you eat.

Causes of vitamin deficiency anemias, also known as megaloblastic anemias, include:

• Folate deficiency anemia. Folate, also known as vitamin B-9, is a nutrient found mainly in fruits and leafy green vegetables. A diet consistently lacking in these foods can lead to a deficiency.

  An inability to absorb folate from food can also lead to a deficiency. Most nutrients from food are absorbed in your small intestine. People with diseases of the small intestine, such celiac disease, or those who have had a large part of the small intestine surgically removed or bypassed may have difficulty absorbing folate or its synthetic form, folic acid. Alcohol decreases absorption of folate, so drinking alcohol to excess may lead to a deficiency. Certain prescription drugs, such as some anti-seizure medications, can interfere with absorption of this nutrient.

  Pregnant women and women who are breast-feeding have an increased demand for folate, as do people undergoing hemodialysis for kidney disease. Failure to meet this increased demand can result in a deficiency.

• Vitamin B-12 deficiency anemia (pernicious anemia). Vitamin B-12 deficiency can result from a diet lacking in vitamin B-12, which is found mainly in meat, eggs and milk. Vitamin B-12 deficiency anemia can also occur if your small intestine can't absorb vitamin B-12. This may be due to surgery to your stomach or small intestine (such as gastric bypass surgery), abnormal bacterial growth in your small intestine, or an intestinal disease, such as Crohn's disease or celiac disease, that interferes with absorption of the vitamin. Vitamin B-12 deficiency can also be caused by a tapeworm ingested from contaminated fish because the tapeworm saps nutrients from your body. However, a vitamin B-12 deficiency is most often due to a lack of a substance called intrinsic factor.

  Intrinsic factor is a protein secreted by the stomach that joins vitamin B-12 in the stomach and escorts it through the small intestine to be absorbed by your bloodstream. Without intrinsic factor, vitamin B-12 can't be absorbed and leaves your body as waste. Lack of intrinsic factor may be due to an autoimmune reaction in which your immune system mistakenly attacks the stomach cells that produce it. Vitamin B-12 deficiency anemia caused by a lack of intrinsic factor is called pernicious anemia.

• Vitamin C deficiency anemia. Vitamin C deficiency can develop if you don't get enough vitamin C from the foods you eat. Vitamin C deficiency is also possible if something impairs your ability to absorb vitamin C from food. For instance, smoking impairs your body's ability to absorb vitamin C.

 

Risk factors for vitamin deficiency anemia vary by type of vitamin deficiency.

Folate deficiency anemia

Your risk of folate deficiency anemia may be increased if:

• You're pregnant, and you aren't taking a multivitamin containing folic acid.
• You have intestinal problems that interfere with absorption of folate.
• You abuse alcohol because alcohol interferes with the absorption of folate.
• You take certain prescription medications, such as some anti-seizure drugs, that can block absorption of folate.
• You're undergoing hemodialysis for kidney failure. Ask your doctor whether you need supplemental folic acid to prevent a deficiency.
• You're undergoing cancer treatment. Some drugs used to treat cancer can interfere with the metabolism of folate.
• You don't eat many fruits and vegetables. If your diet is greatly lacking in fresh fruits and vegetables, or you consistently overcook your food, you may be at risk of folate deficiency anemia.

Vitamin B-12 deficiency anemia (pernicious anemia)

Your risk of vitamin B-12 deficiency anemia may be increased if:

• You don't eat meat and dairy products, foods that contain a lot of vitamin B-12. Vegetarians who don't eat dairy products and vegans, who don't eat any foods from animals, may fall into this category.
• You have an intestinal disease or abnormal bacterial growth in your stomach or have had surgery to your intestines or stomach that interferes with the absorption of vitamin B-12.
• You lack intrinsic factor. Most people with a vitamin B-12 deficiency anemia lack intrinsic factor — a protein secreted by the stomach that is necessary for absorption of vitamin B-12. Lack of intrinsic factor may be due to an autoimmune reaction, or it may be inherited.
• You take certain medications. Antacids and some drugs used to treat type 2 diabetes may interfere with B-12 absorption.
• You have another autoimmune disorder. People with endocrine-related autoimmune disorders, such as diabetes or thyroid disease, may have an increased risk of developing a specific type of vitamin B-12 deficiency anemia called pernicious anemia.

Vitamin C deficiency anemia

Your risk of vitamin C deficiency anemia may be increased if:

• You're malnourished and you're not getting the nutrients and vitamins you need.
• You smoke. Smoking can lead to vitamin C deficiency because it decreases the absorption of this vitamin.
• You abuse alcohol. People who drink heavily don't absorb vitamin C as effectively, putting them at risk of vitamin C deficiency anemia.
• You have a chronic illness. Certain chronic illnesses, such as cancer or chronic kidney disease, increase your risk of vitamin D deficiency anemia by affecting the absorption of vitamin C.

   

  Complications

  Being deficient in vitamins increases your risk of many health problems:

  • Pregnancy complications. Pregnant women with folate deficiency may be more likely to experience complications, such as premature birth. A developing fetus that doesn't get enough folate from its mother can develop birth defects of the brain and spinal cord. If you're thinking of becoming pregnant, ask your doctor whether you should consider taking folic acid supplements so that your body's stores of folate will be enough to support your baby.
  • Nervous system disorders. While vitamin B-12 is important for the production of red blood cells, it's also important for a healthy nervous system. Untreated, vitamin B-12 deficiency can lead to neurological problems, such as persistent tingling in your hands and feet or problems with balance. It can lead to mental confusion and forgetfulness because vitamin B-12 is necessary for healthy brain function. Without treatment for vitamin B-12 deficiency, neurological complications can become permanent. Vitamin B-12 deficiency can cause these and other health problems before it leads to anemia.
  • Scurvy. Vitamin C deficiency can lead to scurvy. Signs and symptoms of this rare disease include bleeding under the skin and around the gums.

New definition of kidney disease for clinical trials could lead to new treatments

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A new study led by researchers at the Johns Hopkins Bloomberg School of Public Health suggests that new therapies for kidney disease could be developed more quickly by revising the definition of kidney disease progression used during clinical trials. If adopted, the new definition could shorten the length of some clinical trials and also potentially encourage more clinical trials in kidney disease. The findings will be published in the June 3, 2014 online edition of the Journal of the American Medical Association.

Chronic kidney disease (CKD) is a worldwide public health problem that affects 26 million people in the U.S., with 600,000 requiring dialysis or kidney transplantation. Despite its prevalence, there are fewer clinical trials for kidney disease than any other common disease. In December 2012, the National Kidney Foundation (NKF) and the Food and Drug Administration (FDA), challenged the research community to evaluate the current definition of kidney disease progression and examine whether improvements were possible. At that time, NFK and FDA officials viewed favorably emerging evidence that a decline in estimated kidney function was promising as a reliable indicator of kidney disease progression. This research grew directly out of the NFK-FDA challenge.

For the study, a global Chronic Kidney Disease Prognosis Consortium led by Josef Coresh, MD, PhD, MHS, a professor at the Bloomberg School, analyzed data from 1.7 million participants recruited into 35 cohorts in dozens of countries from 1975-2011 and followed for an average of 5 years. The researchers' points of comparison were the FDA's current definition of CKD disease onset for clinical trials -- a doubling of serum creatinine, a blood marker that assesses kidney function -- and the emerging evidence on a decline in estimated kidney function.

Researchers first analyzed kidney disease progression among all participants during a baseline period of two years. They then examined how this progression predicted subsequent disease progression to the observed 12,344 cases of end-stage renal diseases (ESRD) and 223,944 deaths. The study found that the current serum-creatinine standard used in clinical trials which is associated with a 57% reduction in kidney function carried very high risk -- a 32-fold increased risk of ESRD and 3.7-fold increased risk of mortality but only occurred in less than 1% of participants in the two-year baseline period.

In contrast, a 30% decline in kidney function, also measured by serum creatinine levels, occurred in 7% of participants in the two-year baseline period. This was associated with a 5-fold higher risk of end-stage renal disease (ESRD) and 1.8-fold higher risk of mortality. This level of risk is high and yet common and early enough to facilitate testing if new therapies are working.

"Chronic kidney disease is often asymptomatic until it's too late," notes Dr. Coresh. "This new definition will help standardize following patients to determine when their disease progresses significantly enough to elevate risk. This will assist in patient care, research studies and development of new therapies."

E-cigarettes may help smokers quit, but research is insufficient

 

June 4, 2014

Deutsches Aerzteblatt International

E-cigarettes are a potential smoking cessation aid and they may also be able to lower the risk of nicotine dependency in high-risk groups. The available scientific evidence, however, remains insufficient. According to an international survey e-cigarettes were used by younger people, those with higher incomes, and heavier smokers in particular. Among e-cigarette users, 85% reported that they used them to stop smoking.

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E-cigarettes are a potential smoking cessation aid and they may also be able to lower the risk of nicotine dependency in high-risk groups. The available scientific evidence, however, remains insufficient. This is the conclusion reached by Dennis Nowak et al. from Munich in this issue of Deutsches Ärzteblatt International.

The authors performed a systematic literature search for data on e-cigarettes’ mechanism of action, their emissions, how they are seen by groups of potential users, their efficacy in smoking cessation, and their addiction potential. According to an international survey e-cigarettes were used by younger people, those with higher incomes, and heavier smokers in particular. Among e-cigarette users, 85% reported that they used them to stop smoking. According to repeat surveys in the U.K., the number of people who were aware of e-cigarettes doubled between 2010 and 2012, and the number of users increased four-fold. An online survey of e-cigarette users found that 74% of those asked had not smoked tobacco for at least several weeks since using e-cigarettes, and 70% reported reduced cigarette cravings. However, there is evidence that people who have never previously smoked also use e-cigarettes. The rates among Polish and US students, for example, were 3% and 9% respectively.

Only two controlled trials show e-cigarettes as having similar effects to nicotine replacement therapies as smoking cessation aids; these effects were almost independent of nicotine content. The authors call for more randomized trials to be conducted.

Tips To Boost Energy And Stop Feeling Tired

 

Every day millions of people complain about being tired, and it is really no wonder, what with the amount of things that we all need to get done in a day. There are so many things to do and so little time to get it done in, and we all wish that there were 25 hours in a day. Most people want to find a way to get more energy and not feel so tired, but are not sure of what they can do about it.

There are actually many simple things that you can do which will help boost your energy and stamina and not only get you going more in the morning but make you feel more energized throughout the day as well.

 

Change Your Diet

One of the first and most important things that you can do if you want to increase your energy is by changing your diet a little bit. You may think that you are eating healthily but when you take a step back and understand more about nutrition you may be pretty surprised at what you find out. White bread for instance, is bad for you and will leave you feeling bloated and sluggish. You should go for the wholemeal version as they are full of fibers. You also want to avoid fatty and sugary foods, especially since they will give you a sugar rush and make you feel more enthused to begin with but then your energy level will drop dramatically.

Perhaps more important than anything is that you make time to have breakfast every morning, as the saying that breakfast is the most important meal of the day is definitely true. By eating breakfast you will basically be giving your body a jumpstart and helping it to feel energized throughout the day. Even if you do not feel hungry you want to eat something for breakfast, even if that just means an egg or a piece of fruit.

 

Eat More Often

Rather than stuffing three large meals down every day, you should try to eat smaller meals but more frequently. You should be snacking healthily throughout each day, so that you keep your metabolism up as fast as possible and keep your body full of sustenance. Eating every two to three hours is the best idea, and this will keep your blood sugar and energy levels stable all day long. Supersized meals demand more energy to digest and in turn this may leave you feeling lethargic.

 

Fill Up On Fiber

Few people get as much fiber in their diet as they should, and fiber is actually one of the most important things to include in any diet. Fiber helps in many ways, namely by flushing toxins and wastes out of your body. These toxins and wastes, if left in your body, would cause you to feel incredibly sluggish and even possibly cause health problems and conditions to develop, such as colon cancer.

 

Use Caffeine to Your Advantage

Although too much caffeine can definitely be unhealthy, if you drink caffeinated beverages in moderation then you can really benefit from it. A cup of coffee in the morning can help make you feel more energized and is always delicious with a good hearty breakfast. Just make sure that you watch your caffeine intake during the later part of the day and into the night, because this can actually result in making you feel more tired. Especially if you are up drinking coffee most of the night you will most likely not be able to sleep and in turn will feel incredibly tired the next day.

 

Don’t Stress Out

Of course these days it seems as though there are a million things to worry about, especially if you have children, but it is important that you do not get stressed out and worry too much. Stressing out causes your brain to overload and as a result you will end up feeling tired and exhausted. Not only can stress make you tired but it can compromise your health and relationships, and so you should definitely try to stay as calm and positive as possible, even during the tougher times.

There are a few things that you can do on the day to day to keep yourself from getting overly stressed and worked up, including learning how to stop talking yourself into being upset and depressed, and how to enjoy the small things in life more. You should also learn how to stop expecting your partner to make you happy and start taking responsibility for your own happiness, as this is one of the biggest downfalls in relationships. Even chores around the house can be turned into something fun rather than something to dread, so just keep your mood light and your spirits up.

Feeling tired is never good especially if you have serious fatigue throughout the day and it is having a negative effect on your life. Just remember that there are many things you can do to get yourself feeling more energized, namely maintaining a proper and healthy diet and exercise regime.

Are your pets disturbing your sleep? You’re not alone

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Rest assured, there may be a good reason you're dog-tired.

While countless pet owners peacefully sleep with a warm pet nearby, a new Mayo Clinic study, presented this week at the 29th Annual Meeting of the Associated Professional Sleep Societies, finds an increase in the number of people experiencing sleep disturbances because of their pets.

A previous Mayo Clinic study published in 2002 reported that of patients who visited the clinic's sleep center and owned pets, only one percent reported any inconvenience from their pets at night. The new study shows a larger number of patients -- 10 percent in 2013 -- reported annoyance that their pets sometimes disturbed their sleep.

"The study determined that while the majority of patients did not view their pets intolerably disturbing their sleep, a higher percentage of patients experienced irritation -- this may be related to the larger number of households with multiple pets," says Lois Krahn, M.D., Mayo Clinic psychiatrist and author of the study. "When people have these kinds of sleep problems, sleep specialists should ask about companion animals and help patients think about ways to optimize their sleep."

Between August and December 2013, 110 consecutive patients at the Mayo Clinic Center for Sleep Medicine in Arizona provided information about pets at night as part of a comprehensive sleep questionnaire. Questions covered the type and number of pets, where the animals slept, any notable behaviors and whether the patient was disturbed. The survey showed that 46 percent of the patients had pets and 42 percent of those had more than one pet. The most popular pets were dogs, cats and birds.

The disturbances by pets that patients reported included snoring, whimpering, wandering, the need to "go outside" and medical needs.

"One patient owned a parrot who consistently squawked at 6 a.m.," Dr. Krahn says. "He must have thought he was a rooster."

Courts face challenges when linking genetics to criminal behavior

 

June 4, 2014

Cell Press

Some people may be at increased risk of criminal behavior due to their genes, some say. Such research holds potential for helping judges and juries with some of the difficult decisions they must make, but it also brings a substantial risk of misinterpretation and misuse within the legal system. Experts suggest that addressing these issues will be of critical importance for upholding principles of justice and fairness.

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Studies suggest that some people may be at increased risk of criminal behavior due to their genes. Such research holds potential for helping judges and juries with some of the difficult decisions they must make, but it also brings a substantial risk of misinterpretation and misuse within the legal system. Addressing these issues will be of critical importance for upholding principles of justice and fairness, according to an essay being published in the June 4 issue of the Cell Press journal Neuron.

"Genetic evidence, properly used, could assist with judgments regarding appropriate criminal punishments, causes of injury or disability, and other questions before the courts," says author Dr. Paul Appelbaum, who directs Columbia University's Center for Research on Ethical, Legal & Social Implications of Psychiatric, Neurologic & Behavioral Genetics.

Genetic evidence is being offered in criminal trials to suggest that defendants have diminished understanding of or control over their behavior, most often in arguments for mitigating sentences -- especially for defendants facing the death penalty. Genetic evidence may also play an increasing role in civil trials regarding issues such as causation of injury. For example, employers contesting work-related mental disability claims might want claimants to undergo genetic testing to prove that an underlying disorder was not responsible for their impairment.

"The complexity of genetic information and our incomplete understanding of the roots of behavior raise the possibility that genetic evidence will be misused or misunderstood. Hence, care is needed in evaluating the extent to which genetic evidence may have something to add to legal proceedings in a given case," says Dr. Appelbaum.

Moving forward, a number of questions must be addressed. For example, to what extent do specific genetic variants make it more difficult to understand or control one's behavior and what are the biological mechanisms involved? Also, how can we respond to individuals with genetic predispositions to criminal behavior to diminish the risk of recidivism?

Dr. Appelbaum notes that it will be an ongoing challenge for both legal and genetic experts to monitor the use of genetic data in the courts to ensure that the conclusions that are drawn validly reflect the science. Without such efforts, judges and juries may overestimate or underestimate the conclusions that can be drawn from genetic evidence, thus unfairly distorting the legal process.

Moving toward quality patient-centered care at cancer hospital

 

June 4, 2014

George Washington University

Patient navigation and survivorship programs were the focus of a new survey, and the challenges many of these programs face. Results indicate that nearly half of respondents had both a navigation and survivorship program at their institution. Full-time navigators had an average patient load of 100-400 patients, in various phases of the cancer continuum of screening, diagnosis, treatment, and posttreatment.

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In order to meet new cancer program accreditation standards, institutions have placed new focus on patient navigation, psychosocial distress screening, and survivorship care plans. Recently published research by the George Washington University (GW) Cancer Institute found these new programs are experiencing "growing pains." The results of a nationwide survey conducted by the GW Cancer Institute and reviewed in the Journal of Oncology Navigation and Survivorship, found that health care professionals could most benefit from greater evaluation of their program's impact.

"This national study from GW Cancer Institute's Center for the Advancement of Cancer Survivorship, Navigation and Policy provides insights into current approaches and barriers for patient-centered care in practice," said Mandi Pratt-Chapman, M.A., director of the GW Cancer Institute. "These findings will help us focus our collective efforts to address identified gaps such as navigation role delineation and how to measure value of these programs."

The survey, completed by 100 healthcare providers -- many of them patient navigators and nurses -- found that nearly half of respondents had both a navigation and survivorship program at their institution. Full-time navigators had an average patient load of 100-400 patients, in various phases of the cancer continuum of screening, diagnosis, treatment, and posttreatment. Respondents identified a wide range of measurements and tracking tools, with a heavy reliance on low-tech options. The greatest challenge area identified was a lack of funding. While demonstrating value was seen as a way to sustain navigation programs, nearly 60 percent of respondents were not tracking value at all. Additionally, role clarity was cited as an important challenge.

The research found that patient navigators assisting patients during screening may be able to navigate a significantly greater number of patients annually than navigators assisting patients after diagnosis; and navigators supporting patients in treatment may need a smaller caseload than navigators supporting patients in other points of the continuum. The results also indicated a need to identify financially sustainable models for patient navigation and clinical survivorship programs, as well as a consensus on core measures.

"Our results provide critical insight into implementation practices as it relates to navigation and survivorship programs from institutions around the country," said Anne Willis, M.A., director of the division of cancer survivorship at the GW Cancer Institute. "These findings will help health care professionals who are working to create and improve programs, where little guidance is available."

Discovery of compound may open new road to diabetes treatment

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Dr. Markus Seeliger and MD/PhD student Zach Foda determined the 3-D structure of an inhibitor compound and how it is bound to the Insulin Degrading Enzyme (IDE). The inhibitor is depicted in orange and white spheres. The IDE is depicted as the blue and green surface, and the gray ribbons.

The discovery of an inhibitor of the Insulin Degrading Enzyme (IDE), a protein responsible for the susceptibility of diabetes because it destroys insulin in the body, may lead to new treatment approaches for diabetes. In collaboration with the discoverers of the inhibitor, David Liu and Alan Saghatelian, Stony Brook Medicine scientist Markus Seeliger, PhD, and colleagues nationally, demonstrated the efficacy of the compound in a research paper in the early online edition of Nature.

More than 20 million people live with type II diabetes in the United States, a disease in which the body cannot make sufficient amounts of the hormone insulin. IDE removes insulin from the blood. To date, diabetes treatment strategies are based on patients either injecting insulin, taking medicine to make their body more sensitive to insulin, or taking other drugs to stimulate insulin secretion. In the paper, "Anti-diabetic action of insulin-degrading enzyme inhibitors mediated by multiple hormones," the authors reveal results that point to a potential new approach -- regulating the degradation of insulin in the blood.

"A strategy to protect the remaining amounts of insulin produced by diabetics in response to blood sugar levels is an attractive treatment alternative, particularly in the early stages of type II diabetes," said Dr. Seeliger, Assistant Professor in the Department of Pharmacological Sciences at Stony Brook University School of Medicine. "The research results gives proof of concept that targeting this protein is extremely promising. The inhibitor we discovered successfully relieved the symptoms of type II diabetes in obese mice and not only elevated their insulin levels but promoted healthy insulin signaling within the blood."

Using a robotic structural biology facility at Stony Brook and resources at Brookhaven National Laboratory, Dr. Seeliger and Zach Foda, an MD/PhD candidate and student in Dr. Seeliger's laboratory, determined the three-dimensional structure of the inhibitor compound and how it is bound to the IDE. The research team used this 3-D structure to help further evaluate the compound's properties and characteristics.

Dr. Seeliger said that the research findings are important initial steps to developing a drug that diabetics can use to regulate the depletion of insulin in their blood. A realistic initial treatment approach, he added, may be to use the compound to help the body retain insulin levels and thus delay the use of insulin for type II diabetes.

Quantum criticality observed in new class of materials

 

Quantum criticality occurs in only a few composite crystalline materials and happens at absolute zero -- the lowest possible temperature in the universe. The paucity of experimental observations of quantum criticality has left theorists wanting in their quest for evidence of possible causes.

The new finding of "quantum critical points" is in a class of iron superconductors known as "oxypnictides" (pronounced OXEE-nick-tydes). The research by physicists at Rice University, Princeton University, China's Zhejiang University and Hangzhou Normal University, France's École Polytechnique and Sweden's Linköping University appears in the journal Nature Materials.

"One of the challenges of studying quantum criticality is trying to completely classify the quantum critical points that have been observed so far," said Rice physicist Qimiao Si, a co-author of the new study. "There are indications that there's more than one type, but do we stop at two? As theorists, we are not yet at the point where we can enumerate all of the possibilities.

"Another challenge is that there are still very few materials where we can say, with certainty, that a quantum critical point exists," Si said. "There's a very strong need, on these general grounds, for extending the materials basis of quantum criticality."

In 2001, Si and colleagues advanced a theory to explain how quantum critical points could give seemingly conventional metals unconventional properties. High-temperature superconductors are one such material, and another is "heavy fermion" metals, so-called because the electrons inside them can appear to be thousands of times more massive than normal.

Heavy fermion metals are prototype systems for quantum criticality. When these metals reach their quantum critical point, the electrons within them act in unison and the effects of even one electron moving through the system have widespread results throughout. This is very different from the electron interactions in a common wiring material like copper. It is these collective effects that have increasingly convinced physicists of a possible link between superconductivity and quantum criticality.

"The quantum critical point is the point at which a material undergoes a transition from one phase to another at absolute zero," said Si, Rice's Harry C. and Olga K. Wiess Professor of Physics and Astronomy. "Unlike the classical phase transition of ice melting into water, which occurs when heat is provided to the system, the quantum phase transition results from quantum-mechanical forces. The effects are so powerful that they can be detected throughout the space inside the system and over a long time."

To observe quantum critical points in the lab, physicists cool their samples -- be they heavy fermion metals or high-temperature superconductors -- to extremely cold temperatures. Though it is impossible to chill anything to absolute zero, physicists can drive the phase transition temperatures to attainable low temperatures by applying pressure, magnetic fields or by "doping" the samples to slightly alter the spacing between atoms.

Si and colleagues have been at the forefront of studying quantum critical points for more than a decade. In 2003, they developed the first thermodynamic method for systematically measuring and classifying quantum critical points. In 2004 and again in 2007, they used tests on heavy fermion metals to show how the quantum critical phenomena violated the standard theory of metals -- Landau's Fermi-liquid theory.

In 2008, following the groundbreaking discovery of iron-based pnictide superconductors in Japan and China, Si and colleagues advanced the first theory that explained how superconductivity develops out of a bad-metal normal state in terms of magnetic quantum fluctuations. Also that year, Si co-founded the International Collaborative Center on Quantum Matter (ICC-QM), a joint effort by Rice, Zhejiang University, the London Centre for Nanotechnology and the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany.

In 2009, Si and co-authors offered a theoretical framework to predict how the pnictides would behave at or near a quantum critical point. Several of these predictions were borne out in a series of studies the following year.

In the current Nature Materials study, Si and ICC-QM colleagues Zhu'an Xu, an experimentalist at Zhejiang, and Jianhui Dai, a theorist at Hangzhou, worked with Antoine Georges of École Polytechnique, Nai Phuan Ong of Princeton and others to look for evidence of quantum critical points in an iron-based heavy fermion metallic compound made of cerium, nickel, arsenic and oxygen. The material is related to the family of iron-based pnictide superconductors.

"Heavy fermions are the canonical system for the in-depth study of quantum criticality," Si said. "We have considered heavy fermion physics in the iron pnictides before, but in those compounds the electrons of the iron elements are ordered in such a way that it makes it more difficult to precisely study quantum criticality.

"The compound that we studied here is the first one among the pnictide family that turned out to feature clear-cut heavy fermion physics. That was a pleasant surprise for me," Si said.

Through measurements of electrical transport properties in the presence of a magnetic field, the study provided evidence that the quantum critical point belongs to an unconventional type proposed in the 2001 work of Si and colleagues.

"Our work in this new heavy fermion pnictide suggests that the type of quantum critical point that has been theoretically advanced is robust," Si said. "This bodes well with the notion that quantum criticality can eventually be classified."

He said it is important to note that other homologues -- similar iron-based materials -- may now be studied to look for quantum critical points.

"Our results imply that the enormous materials basis for the oxypnictides, which has been so crucial to the search for high-temperature superconductivity, will also play a vital role in the effort to establish the universality classes of quantum criticality," Si said.

Additional co-authors include Yongkang Lou, Yuke Li, Chunmu Feng and Guanghan Cao, all of Zhejiang University; Leonid Pourovskii of both École Polytechnique and Linköping University; and S.E. Rowley of Princeton University.

The research was supported by the National Basic Research Program of China, the National Science Foundation of China, the NSF of Zhejiang Province, the Fundamental Research Funds for the Central Universities of China, the National Science Foundation, the Nano Electronics Research Corporation, the Robert A. Welch Foundation, the China Scholarship Council and the Swedish National Infrastructure for Computing.

Emotion drives customers to use smartphones with bigger screen

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Bigger smartphone screen size may be better for more than just practical reasons, according to researchers. Participants in a study on smartphones indicated that emotional reasons might influence their decision to buy smartphones with bigger screens even more than practical ones, said S. Shyam Sundar, Distinguished Professor of Communications and co-director of the Media Effects Research Laboratory, Penn State.

"There are basically two different reasons that 'bigger is better' for screen size: utilitarian reasons and affective, or emotional, reasons," said Sundar. "There are so many things on smartphones that we can use, but an even more powerful factor of the larger screen is its hedonic aspect -- how attractive and pleasing it is to users."

People may find bigger screens more emotionally satisfying because they are using smartphones for entertainment, as well as for communication purposes.

"The screen size has increased the bandwidth of user interactions on smartphones, making it more than a talking-texting device," said Sundar. "With high definition screens, people now can watch television and movies, as well as multi-task, something that wasn't possible in earlier smartphone versions."

The desire for larger screens that drives purchases of other entertainment devices may be part of the impulse to buy smartphones with larger screens, said Ki Joon Kim, adjunct professor in the department of interaction science, Sungkyunkwan University, Korea, who worked with Sundar on the study.

"Large-screen TVs and monitors are known to have positive effects on user experience," said Kim. "Our study found that the same applies to the mobile context as well."

Smartphone engineers cannot increase the size of the screen continually or the mobile device will become inconvenient to carry.

"We have not reached the point where the screen is too big yet, and I believe there may be some room for expansion of the screen size," said Sundar. "Finding the idea size is something that I'm sure industry engineers and designers are working to find." Kim said that this appeal to both practical and emotional needs of users may indicate that smartphones can handle the merging of various forms of media.

"Smartphones serve both utilitarian and hedonic purposes," Kim said. "They are convergent media." The researchers randomly assigned smartphones with two different screen sizes to 130 university students. One of the phones had a 3.7-inch screen and the other had a 5.3-inch screen size. They then asked the participants to visit a mobile website and find the departure time for a shuttle bus.

Participants were then asked to fill out a questionnaire on their experience using the smartphone. The questions included ones on how they used the device, such as whether or not the smartphone helped them locate the bus schedule, and on how they felt about using the phone, such as whether or not they felt excited about using it.