Fundamental Matter-Antimatter Symmetry Confirmed

Artist's rendering of an antiproton (black sphere) trapped inside a helium atom being probed by two laser beams. (Credit: Image courtesy of Max Planck Institute of Quantum Optics)

Science Daily — An international collaboration including Max Planck Institute of Quantum Optics scientists has set a new value for the antiproton mass relative to the electron with unprecedented precision.

Now the independent research group “Antimatter Spectroscopy” of Dr. Masaki Hori, which is associated with the Laser Spectroscopy Division of Prof. Theodor W. Hänsch at the Max Planck Institute of Quantum Optics, has measured the mass of the antiproton relative to the electron with a precision of 1.3 parts per billion (Nature, 28 July 2011). For this they used a new method of laser spectroscopy on a half-antimatter, half-matter atom called antiprotonic helium. The result agreed with the proton mass measured to a similar level of precision, confirming the symmetry between matter and antimatter. The experiment was carried out at the European Laboratory for Particle Physics (CERN) in Geneva (Switzerland) in a project led by scientists from the Max Planck Institute of Quantum Optics and Tokyo University (Japan), and including the University of Brescia (Italy), the Stefan Meyer Institute (Vienna, Austria), and the KFKI Research Institute (Budapest, Hungary).According to modern cosmology, matter and antimatter were created in equal amounts in the Big Bang at the beginning of the universe. Physicists are developing concepts to explain why the visible universe now seems to be made entirely out of matter. On the other hand, experimental groups are producing antimatter atoms artificially to explore the fundamental symmetries between matter and antimatter, which according to the present theories of particle physics should have exactly the same properties, except for the opposite electrical charge).

Physicists believe that the laws of nature obey a fundamental symmetry called “CPT” (this stands for charge conjugation, parity, and time reversal), which postulates that if all the matter in the universe were replaced with antimatter, left and right inverted as if looking into a mirror, and the flow of time reversed, this “anti-world” would be indistinguishable from our real matter world. Antimatter atoms should weigh exactly the same as their matter counterparts. If scientists were to experimentally detect any deviation, however small, it would indicate that this fundamental symmetry is broken. “Small” is the keyword here – it is essential to use the most precise methods and instruments available to make this comparison with the highest possible precision.

Antimatter is extraordinarily difficult to handle in the laboratory, because upon coming into contact with ordinary matter (even the air molecules in a room), it immediately annihilates, converting into energy and new particles. In 1997, researchers from the Max Planck Institute of Quantum Optics in cooperation with other European, Japanese, and American groups began construction of a facility called the Antiproton Decelerator (AD) at CERN. Here antiprotons produced in high-energy collisions are collected and stored in a vacuum pipe arranged in a 190-m-long racetrack shape. The antiprotons are gradually slowed down, before being transported to several experiments. The so-called ASACUSA¹ (Atomic Spectroscopy and Collisions using Slow Antiprotons, named after a district in Tokyo) collaboration, of which Dr. Hori is one of the project leaders, sends the antiprotons into a helium target to create and study antiprotonic helium atoms.

Normal helium atoms consist of a nucleus with two electrons orbiting around it. In antiprotonic helium, one of these electrons is replaced by an antiproton, which finds itself in an excited orbit some 100 picometres (10^-10 m) from the nucleus. Scientists fire a laser beam onto the atom, and carefully tune its frequency until the antiproton makes a quantum jump from one orbit to another. By comparing this frequency with theoretical calculations, the mass of the antiproton can be determined relative to the electron.

An important source of imprecision arises because the antiprotonic atoms jiggle around randomly according to their thermal energy, so that atoms moving towards the laser beam experience a different frequency compared to those moving away. This is similar to the effect that causes the siren of an approaching ambulance to change pitch as it passes you by. In their previous experiments of 2006, the MPQ / ASACUSA scientists used one laser beam, and this effect limited the precision of their measurement.

This time to go beyond this limit, a technique called “two-photon laser spectroscopy” was used. The atoms were struck by two laser beams travelling in opposite directions, with the result that the effect was partially cancelled, leading to a four to six times higher precision. The first laser caused the antiproton to make a quantum jump to a virtual energy level normally not allowed by quantum mechanics, so that the second laser could actually bring the antiproton up to the closest allowed state. Such a two-photon jump is normally difficult to achieve because the antiproton is heavy, but MPQ scientists accomplished it by building two ultra-sharp lasers and carefully choosing a special combination of laser frequencies. To do this, an optical frequency comb – a special device invented 10 years ago by the group of Prof. Theodor W. Hänsch to measure the frequency of light – was used.

The new measurements showed that the antiproton is 1836.1526736(23) times heavier than the electron, the parenthesis showing the 1-standard deviation imprecision. “We have measured the mass of the antiproton relative to the electron with a precision of 10 digits, and have found it exactly the same as the proton value known with a similar precision”, Masaki Hori explains. “This can be regarded as a confirmation of the CPT theorem. Furthermore, we learned that antiprotons obey the same laws of nonlinear quantum optics like normal particles, and we can use lasers to manipulate them. The two-photon technique would allow much higher precisions to be achieved in the future, so that ultimately the antiproton mass may be better known than the proton one.”

The Committee on Data for Science and Technology (CODATA) uses the results of this experiment as one of several input data to determine the proton-to-electron mass ratio, which in turn influences the values of many other fundamental constants. Olivia Meyer-Streng

¹ASACUSA is one of several experiments studying antimatter at CERN. ATRAP and ALPHA investigate antihydrogen atoms, AeGIS studies how antihydrogen falls under gravity, and ACE studies the possible use of antiprotons for cancer therapy.

World Population to Surpass 7 Billion in 2011; Explosive Population Growth Means Challenges for Developing Nations

In 2011, global population is expected to hit 7 billion. (Credit: © Feng Yu / Fotolia) Science Daily  — Global population is expected to hit 7 billion later this year, up from 6 billion in 1999. Between now and 2050, an estimated 2.3 billion more people will be added -- nearly as many as inhabited the planet as recently as 1950. New estimates from the Population Division of the Department of Economic and Social Affairs of the United Nations also project that the population will reach 10.1 billion in 2100. These sizable increases represent an unprecedented global demographic upheaval, according to David Bloom, Clarence James Gamble Professor of Economics and Demography at the Harvard School of Public Health, in a review article published July 29, 2011 in Science. Over the next forty years, nearly all (97%) of the 2.3 billion projected increase will be in the less developed regions, with nearly half (49%) in Africa. By contrast, the populations of more developed countries will remain flat, but will age, with fewer working-age adults to support retirees living on social pensions. "Although the issues immediately confronting developing countries are different from those facing the rich countries, in a globalized world demographic challenges anywhere are demographic challenges everywhere," said Bloom. The world's population has grown slowly for most of human history. It took until 1800 for the population to hit 1 billion. However, in the past half-century, population jumped from 3 to 7 million. In 2011, approximately 135 million people will be born and 57 million will die, a net increase of 78 million people. Considerable uncertainty about these projections remains, Bloom writes. Depending on whether the number of births per woman continues to decline, the ranges for 2050 vary from 8.1 to 10.6 billion, and the 2100 projections vary from 6.2 to 15.8 billion. Population trends indicate a shift in the "demographic center of gravity" from more to less developed regions, Bloom writes. Already strained, many developing countries will likely face tremendous difficulties in supplying food, water, housing, and energy to their growing populations, with repercussions for health, security, and economic growth. "The demographic picture is indeed complex, and poses some formidable challenges," Bloom said. "Those challenges are not insurmountable, but we cannot deal with them by sticking our heads in the sand. We have to tackle some tough issues ranging from the unmet need for contraception among hundreds of millions of women and the huge knowledge-action gaps we see in the area of child survival, to the reform of retirement policy and the development of global immigration policy. It's just plain irresponsible to sit by idly while humankind experiences full force the perils of demographic change."

Programmed cell death in plants revealed

LA TROBE UNIVERSITY

Arabidopsis plant used for genetic research Image: dra_schwartz/iStockphoto Research at La Trobe University has provided new insight into how programmed cell death may be controlled in plants. The work, led by plant biologist Professor Roger Parish, is reported in the latest issue of the international scientific journal, The Plant Cell, published by the American Society of Plant Biologists. As the world’s population rises and demand for food and bio-fuel increases, it has important implications for improving agricultural crop production. Key to the La Trobe study is the discovery of an enzyme, aspartic protease, called ‘UNDEAD’ With its Zombie connotation, the enzyme helps decide such things as when cells in the tapetal layer – which provides building blocks for the pollen – live or die. ‘One of the big issues in plants, just as in animals and humans, is programmed cell death,’ explains Professor Parish. ‘To date nobody has really known how it works in plants. There have been lots of theories. ‘It’s very important for plant development that certain cells die at the right time so that the plant can develop and reproduce – so this new work is a real breakthrough,’ he says. Other members of the La Trobe research team are Dr Huy Anh Phan, Dr Sylvana Iacuone, and Dr Song F Li. The new discovery follows previous studies by Professor Parish’s research group on male sterility and anther development in plants. This has already led to new technology for hybrid seed production. The researchers are also working on ways to help protect plants against cold and dehydration. A few years ago the La Trobe group discovered a ‘Godfather’ gene (AtMYB80) which acts as a master ‘switch’ for pollen production.  When researchers ‘knocked out’ this gene, plants became male sterile. When they reversed the process, re-inserting the gene with some modification, plants again began to produce pollen. It is this system that is now used to produce seeds with ‘hybrid vigour’, a trait which leads to increased yields. Key to producing hybrid seeds is the ability to stop plants from self pollinating. This system can also be used to contain genetically engineered plants, and stop seeds from setting so plants can direct extra energy into making more leaves. The latest La Trobe research also provides insights into the role of a host of other biochemical players involved in the process of cell death that is triggered by the master gene. The researchers identified more than 400 genes controlled by the master gene. They isolated and identified various suspects and tracked down one that ‘codes’ for an aspartic protease enzyme called UNDEAD that digests, or breaks down, other proteins. ‘This gene, along with AtMYB80, appears to regulate the timing of programmed cell death in the tapetum,’ says Professor Parish. The La Trobe research was carried out on Arabidopsis thaliana, or thale cress. The same genes are found in wheat, barley, canola, cotton, broccoli, rice, cabbage – and even poplar trees. So the work can be applied to improve plants for a wide range of agricultural industries. Professor Parish’s lab also specialises in the mechanisms of seed mucilage production and seed coat development. It is funded by the Grains Research and Development Council, the Australian Research Council and the company Pacific Seeds.

Tiny shocks help schizophrenics

NEUROSCIENCE RESEARCH AUSTRALIA

Brain function in people with schizophrenia improves after 20 minutes of being subjected to very mild, painless electrical current to the brain through electrodes on the scalp, a study found. Image: cosmin4000/iStockphoto In a recent study using a technique called transcranial Direct Current Stimulation (tDCS), scientists from Neuroscience Research Australia (NeuRA) have shown that brain function in people with schizophrenia can improve after applying the stimulation for just 20 minutes. “We found that this type of brain stimulation boosted learning from feedback which is important in everyday life, for example, in learning to act on cues from other people in social situations,” says lead researcher Dr Tom Weickert. “There are very few new treatment options for people with schizophrenia, so finding a different treatment that is promising and has little in the way of side effects is very exciting,” he says. tDCS transmits a very mild electrical current to the brain through electrodes on the scalp. This technique has previously been shown to improve brain function in healthy people and people with depression. The study applied tDCS to a region of the brain called the pre-frontal cortex of people with schizophrenia for 20 minutes. One of the characteristics of schizophrenia is reduced brain activity in the pre-frontal cortex, an area at the front of the brain used for thinking, motivation and learning. During the application, participants were asked to complete a computer task designed to measure improvements in a type of learning called ‘implicit learning’, in this case learning to predict the weather (rain or shine) using tarot cards. The team found that tDCS improved learning abilities in those people who already showed some potential to learn during an initial testing session without brain stimulation. “The brain stimulation may encourage other nerve cells close by to become active and improve learning,” says Dr Weickert. The next step in the research is to determine whether the brain stimulation technique has a lasting effect on learning abilities. The study, in which participants will receive 20 minutes of tDCS five days a week for four weeks, is already underway. The research was published in the journal Schizophrenia Research.

Growing ‘Epidemic’ of Heart Attacks, Strokes, Cancer, Diabetes Threatens China’s Economic and Social Well-Being

Addressing non-communicable diseases could let China set an example for the world

BEIJING July 26, 2011 – Non-communicable diseases (NCD)[1] such as cancer, diabetes, cardiovascular diseases and chronic respiratory illnesses are China’s number one health threat, accounting for over 80 percent of annual deaths and contributing to 68.6 percent of the country’s total disease burden, says a World Bank report released today.

While this rising ‘epidemic’ has serious implications for the country’s future prosperity, the report suggests that China can seize the opportunity to respond effectively, providing a powerful example for other countries worldwide where an increase in these diseases is becoming a major challenge. 

The report Toward a Healthy and Harmonious Life in China: Stemming the Rising Tide of Non-Communicable Diseases was prepared in coordination with the Chinese Ministry of Health and the World Health Organization, based on assessments conducted by the World Bank in 2008-2010. It presents evidence on the economic and social consequences of explosive increases in NCDs in China and proposes a range of policies and strategies to confront and prevent them.

According to the report, the number of cases of cardiovascular diseases, chronic obstructive pulmonary diseases, diabetes and lung cancer among Chinese people over 40 will double or even triple over the next two decades if effective prevention and control strategies are not implemented. This trend is rooted in the social, economic, and environmental changes the country has experienced in recent decades, in particular, the rapid aging of the population and exposure to health risk factors such as high smoking rates among males, growing obesity due to increased consumption of fast foods rich in fat and salt, sugar-rich soft drinks and decreased physical activity in cities.

 “First and foremost, it is the human toll that should concern policy-makers when addressing NCDs. Mounting medical costs have a severe impact on individual and families when NCD occurs, and loss of loved ones causes immense grief that could have been avoided with the right policies in place”, said Klaus Rohland, World Bank Country Director for China. “But there is substantial economic cost associated with NCDs as well.”

For example, estimates for China presented in this report indicate that the economic benefit of reducing cardiovascular diseases by one percent per year over a 30-year period (2010–2040) could generate an economic value equivalent to 68 percent of China’s real GDP in 2010, more than US$10.7 trillion.

If an effective response is not mounted, warns the report, the disease burden will aggravate the economic and social impact of the expected population increase of older citizens and a smaller workforce in China.  The report notes that a less healthy workforce and an elderly population that is chronically ill will increase the odds of a future economic slowdown and pose significant social challenges in China.

The report identifies the coming ten years as a critical time for China to prevent and control the ‘epidemic’, stressing that much of the country’s NCD burden can be avoided or managed by adopting good practices that have been proven effective internationally, tailored to local conditions.

“Cost-effective policy options exist for adopting a comprehensive multisectoral response to deal with NCDs in China,” said Shiyong Wang, a World Bank Senior Health Specialist and the lead author of the report. “With more healthy behavior, improved socioeconomic environments conducive to health, and expanded access to quality health services, not only do people live longer, but their quality of life is also improved by the reduction of sickness and disability.” 

Data from successful efforts in developed countries reveal that health improvements occur in a shorter time frame than commonly believed – within a year or a few years rather than decades – after the reduction and elimination of the exposure to major health risk factors.

According to Patricio Marquez, a World Bank Lead Health Specialist, as co-author of the report: “this can be accomplished through higher excise taxes on tobacco and alcohol products, regulatory measures to curtail advertisement and restrict smoking in public places, information, education and communication activities to educate the population about these risks, as well as a redesigned health system that gives people timely access to quality medical care, particularly to well organized and funded primary health care services.”

The report concludes that a healthier and more productive population is critical to ensuring sustainable economic growth and harmonious social development in China over the medium and longer term.

[1] NCDs are a set of chronic diseases, including cardiovascular disease, cancers, chronic respiratory diseases, and diabetes, characterized by a long latency period, prolonged clinical course and debilitating manifestations.

Research discovers genetic link to Barrett's esophagus, esophageal cancer

by Biomechanics 

                5-year study identifies genes that predispose for BE/EAC.  

Researchers have identified genetic mutations in patients with Barrett's esophagus (BE) and/or the cancer esophageal adenocarcinoma (EAC). None of these mutations were found in patients not affected by BE/EAC, suggesting a previously unknown heritable cause. Identifying genetic markers will allow risk assessment, early detection, improved disease management, and ultimately increased survival. 

BE is estimated to occur in up to 10 percent of the population, and its incidence has increased more than three-fold since 1970. Related to gastroesophageal reflux disease (GERD), BE is believed to be a precursor to EAC. EAC is typically not diagnosed until its advanced stages, when chances of survival are poor. 

This study, published in the July 27, 2011 issue of the Journal of the American Medical Association and led by Charis Eng, M.D., Ph.D., Chair and Founding Director of the Genomic Medicine Institute of Lerner Research Institute at Cleveland Clinic, was conducted from 2005 to 2010 at 16 different institutions across the United States and involved 298 participants with BE, EAC, or both. To identify genes linked specifically to BE/EAC, the group used the latest in genomics approaches and state-of-the art technology, along with functional genomic validation, to identify MSR1, ASCC1, and CTHRC1 as three genes mutated in 11 percent of the BE/EAC patients studied, indicative of a significant genetic predisposition. Mutations in MSR1 were the most common, affecting seven percent of the patients studied. 

Identifying BE/EAC predisposition genes also gives valuable insight to how the disease occurs. Preliminary evidence from this study suggests a role for specific molecular pathways, including inflammation, in the development of BE/EAC, as well as a potential link of the mutated genes to additional cancers as well. 

"We are absolutely thrilled to now know three distinct genes that link to BE/EAC," said Dr. Eng. "This is essential for improving risk assessment, disease management, and saving lives."

How the modular structure of proteins permits evolution to move forward

Posted by Biomechanism 

The development of identical egg laying organs of two nematode species is regulated by different signaling pathways.

Changes in a short protein domain can alter a whole signaling network involved in organ development– this is the key result of a comparative study of the development of the egg laying organ in two species of nematodes. However, the outward appearance of the organ remains the same in both species. The study provides support for the theory of developmental systems drift – a theory maintaining that, over the course of evolution, analogous organs of different species can retain the same shape and function while the regulative mechanisms underlying their development can change considerably.

The new results, published July 26 in the online, open-access journal PLoS Biology, raise the question of whether the modular structure of proteins creates space for evolutionary development, even in otherwise highly conserved structures of organs and signaling pathways.

A nematode with the scientific name of Caenorhabditis elegans is commonly used in life science studies. This organism has a transparent body measuring about 1 mm. Photo: Riken Research

The nematode Caenorhabditis elegans (C. elegans) is a model organism of genetics. The worm is only about one millimeter long, and its genome has been completely sequenced, so scientists can trace the fate of every one of its 959 cells. In research lasting more than a decade, Ralf Sommer, Director of the Department for Evolutionary Biology at the Max Planck Institute for Developmental Biology in Tübingen, Germany, has established as a comparative model organism, a second nematode, Pristionchus pacificus (P. pacificus).

At first sight, this species resembles C. elegans, but it belongs to another family. The last common ancestor of the two species lived 250 to 420 million years ago, well before the zenith of the dinosaurs. “For [this sort of] comparison, the organisms should not be too closely related, since very small differences in the genome cannot be easily assigned to single events in the evolution,” explains Xiaoyue Wang, first author of the study. “The two worms are ideal and a wide variety of genetic and molecular tools is available.” The scientists studied the development of the worms’ egg laying organ, the vulva, which looks identical in both species and is induced to develop from six precursor cells by signals emanating from surrounding tissues

To more thoroughly test the validity of the theory of developmental systems drift, Xiaoyue Wang analyzed the induction of vulva development from a signaling center in the posterior part of P. pacificus using genetic and molecular methods. The system was used because while similar signaling pathways are involved in vulva development of both species, they appear to exert their molecular activities in different ways: “I have found a single mutation in a stop element of the DNA, where in C. elegans the production of a protein ends, but in P. pacificus the protein is extended by 17 amino acids,” Wang says. The protein, which functions as a receptor, obtains an additional binding site through the extension that enables it to interact with another signaling pathway.

Evolution seems to use the existing signaling pathways almost like a modular construction system: In P. pacificus, a novel binding site connects a different signaling pathway which is then used in a novel context.

Wang continues, “I don’t believe that what we have discovered in our study of nematodes is an unusual exception. Similar processes are known to lead to cancer development in humans. But likewise, they can initiate changes that can become subject to natural selection and eventually be propagated in the course of evolution.” The observation that changes in the regulatory mechanisms do not lead to changes in the organ could be due to redundancy.

In the development of the vulva of the nematodes, for example, several mechanisms acting in parallel have already been described. The modular design of proteins makes it possible to conserve important parts of the molecule over the long time of evolution, while creating opportunities for short protein domains to change. The overall impact of these mechanisms in evolution remains to be investigated.

______________________

Funding: This work was funded by the Max-Planck Society. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Citation: Wang X, Sommer RJ (2011) Antagonism of LIN-17/Frizzled and LIN-18/Ryk in Nematode Vulva Induction Reveals Evolutionary Alterations in Core Developmental Pathways. PLoS Biol 9(7): e1001110. doi:10.1371/journal.pbio.1001110