The phase problem remains a major barrier to overcome in protein structure solution by X-ray crystallography. In recent years, new molecular-replacement approaches using ab initio models and ideal secondary-structure components have greatly contributed to the solution of novel structures in the absence of clear homologues in the PDB or experimental phasing information. This has been particularly successful for highly α-helical structures, and especially coiled-coils, in which the relatively rigid α-helices provide very useful molecular-replacement fragments. This has been seen within the program AMPLE, which uses clustered and truncated ensembles of numerous ab initio models in structure solution, and is already accomplished for α-helical and coiled-coil structures. Here, an expansion in the scope of coiled-coil structure solution by AMPLE is reported, which has been achieved through general improvements in the pipeline, the removal of tNCS correction in molecular replacement and two improved methods for ab initio modelling. Of the latter improvements, enforcing the modelling of elongated helices overcame the bias towards globular folds and provided a rapid method (equivalent to the time requirements of the existing modelling procedures in AMPLE) for enhanced solution. Further, the modelling of two-, three- and four-helical oligomeric coiled-coils, and the use of full/partial oligomers in molecular replacement, provided additional success in difficult and lower resolution cases. Together, these approaches have enabled the solution of a number of parallel/antiparallel dimeric, trimeric and tetrameric coiled-coils at resolutions as low as 3.3 Å, and have thus overcome previous limitations in AMPLE and provided a new functionality in coiled-coil structure solution at lower resolutions. These new approaches have been incorporated into a new release of AMPLE in which automated elongated monomer and oligomer modelling may be activated by selecting `coiled-coil' mode.

Grazing-incidence small-angle X-ray scattering (GISAXS) coupled with computed tomography (CT) has enabled the visualization of the spatial distribution of nanostructures in thin films. 2D GISAXS images are obtained by scanning along the direction perpendicular to the X-ray beam at each rotation angle. Because the intensities at the q positions contain nanostructural information, the reconstructed CT images individually represent the spatial distributions of this information (e.g. size, shape, surface, characteristic length). These images are reconstructed from the intensities acquired at angular intervals over 180°, but the total measurement time is prolonged. This increase in the radiation dosage can cause damage to the sample. One way to reduce the overall measurement time is to perform a scanning GISAXS measurement along the direction perpendicular to the X-ray beam with a limited interval angle. Using filtered back-projection (FBP), CT images are reconstructed from sinograms with limited interval angles from 3 to 48° (FBP-CT images). However, these images are blurred and have a low image quality. In this study, to optimize the CT image quality, total variation (TV) regularization is introduced to minimize sinogram image noise and artifacts. It is proposed that the TV method can be applied to downsampling of sinograms in order to improve the CT images in comparison with the FBP-CT images.

Single-crystalline-like thin films composed of crystallographically aligned grains are a new prototype of 2D materials developed recently for low-cost and high-performance flexible electronics as well as second-generation high-temperature superconductors. In this work, significant texture improvement in single-crystalline-like materials is achieved through growth of a 330 nm-thick silver layer.

Single-wavelength X-ray anomalous diffraction (SAD) is a frequently employed technique to solve the phase problem in X-ray crystallography. The precision and accuracy of recovered anomalous differences are crucial for determining the correct phases. Continuous rotation (CR) and inverse-beam geometry (IBG) anomalous data collection methods have been performed on tetragonal lysozyme and monoclinic survivin crystals and analysis carried out of how correlated the pairs of Friedel's reflections are after scaling. A multivariate Bayesian model for estimating anomalous differences was tested, which takes into account the correlation between pairs of intensity observations and incorporates the a priori knowledge about the positivity of intensity. The CR and IBG data collection methods resulted in positive correlation between I(+) and I(−) observations, indicating that the anomalous difference dominates between these observations, rather than different levels of radiation damage. An alternative pairing method based on near simultaneously observed Bijvoet's pairs displayed lower correlation and it was unsuccessful for recovering useful anomalous differences when using the multivariate Bayesian model. In contrast, multivariate Bayesian treatment of Friedel's pairs improved the initial phasing of the two tested crystal systems and the two data collection methods.

As the host of PBS’s “Scientific American Frontiers,” Alan Alda has interviewed scientists, physicists, neuroscientists, and academics. Forging a connection with these guests through freewheeling […]

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In 1909, naturalist Dr. Edgar A. Mearns joined Theodore Roosevelt and scientists from the Smithsonian and New York’s American Museum of Natural History on an […]

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The same artificial intelligence technique typically used in facial recognition systems could help improve prediction of hailstorms and their severity, according to a new, National Science Foundation-funded study. Instead of zeroing in on the features of an individual face, scientists trained a deep learning model called a convolutional neural network to recognize features of individual storms that affect the formation of hail and how large the hailstones will be, both of which are notoriously difficult to predict. The promising results highlight the importance of taking into account a storm's entire structure, something that's been challenging to do with existing hail-forecasting techniques.

Image credit: Carlye Calvin

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Machine learning algorithms can sometimes do a great job with a little help from human expertise, at least in the field of materials science. In many specialized areas of science, engineering and medicine, researchers are turning to machine learning algorithms to analyze data sets that have grown too large for humans to understand. In materials science, success with this effort could accelerate the design of next-generation advanced functional materials, where development now usually depends on old-fashioned trial and error. By themselves, however, data analytics techniques borrowed from other research areas often fail to provide the insights needed to help materials scientists and engineers choose which of many variables to adjust -- and the techniques can't account for dramatic changes such as the introduction of a new chemical compound into the process. In a new study, researchers explain a technique known as dimensional stacking, which shows that human experience still has a role to play in the age of machine intelligence. The machines gain an edge at solving a challenge when the data to be analyzed are intelligently organized based on human knowledge of what factors are likely to be important and related. "When your machine accepts strings of data, it really does matter how you are putting those strings together," said Nazanin Bassiri-Gharb, the paper's corresponding author and a scientist at the Georgia Institute of Technology. "We must be mindful that the organization of data before it goes to the algorithm makes a difference. If you don't plug the information in correctly, you will get a result that isn't necessarily correlated with the reality of the physics and chemistry that govern the materials."

Image credit: Rob Felt/Georgia Tech

Widespread reforms are needed to ensure that all children are equipped with the skills and instruction they need to learn to read, according to a new report from a committee of the National Research Council.

Increased research is the key to developing more widely applicable detection systems to find pipe bombs before they explode and to help catch the perpetrators when a bomb has gone off, says a new report from a committee of the National Research Council.

The nations health care industry has foundered in its ability to provide safe, high-quality care consistently to all Americans, says a new report from the Institute of Medicine of the National Academies. Reorganization and reform are urgently needed to fix what is now a disjointed and inefficient system.

Recent strides in biotechnology offer the promise of new and innovative applications -- from edible vaccines to protein-based electronics components.

Welcome to the public release of the latest Institute of Medicine report on the quality of health care in America.

To significantly reduce the tens of thousands of deaths and injuries caused by medical errors every year, health care organizations must adopt information technology systems that are capable of collecting and sharing essential health information on patients and their care, says a new report by the Institute of Medicine of the National Academies.

Nearly half of all American adults – 90 million people – have difficulty understanding and using health information, and there is a higher rate of hospitalization and use of emergency services among patients with limited health literacy, says a new report from the Institute of Medicine of the National Academies.

To enhance the vitality and overall operation of the nations patent system, federal officials should take decisive steps to increase the systems flexibility, openness, and reliability, says a new report from the National Academies National Research Council.

Long-term population trends for some North American pollinators -- bees, birds, bats, and other animals and insects that spread pollen so plant fertilization can occur -- are demonstrably downward, says a new report from the National Research Council.

Despite being used for several decades, test-based incentives have not consistently generated positive effects on student achievement, says a new report from the National Research Council.

Americas health care system has become too complex and costly to continue business as usual, says a new report from the Institute of Medicine

The Institute of Medicine today presented the 2012 Gustav O. Lienhard Award to Donald M. Berwick, a physician whose work has catalyzed a national movement to improve health care quality and safety.

Insufficient sleep can decrease a commercial motor vehicle (CMV) driver’s level of alertness, which may increase the risk of a crash, yet little is known about effective ways to minimize that risk, says a new report from the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine identifies six promising practices to improve health care for individuals with social risk factors for poor health care outcomes, such as people who are in a low socio-economic position, reside in disadvantaged neighborhoods, identify as a racial or ethnic minority, or possess limited health literacy.

The 2011 Fukushima Daiichi nuclear accident should serve as a wake-up call to nuclear plant operators and regulators on the critical importance of measuring, maintaining, and restoring cooling in spent fuel pools during severe accidents and terrorist attacks, says a new report from the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine says that Medicare’s value-based payment programs could take into account social risk factors – such as low socio-economic position, residence in disadvantaged neighborhoods, or race and ethnicity – but any proposal to do so will entail both advantages and disadvantages that need to be carefully considered.

A new report from the National Academies of Sciences, Engineering, and Medicine offers a road map and recommendations to help U.S. cities work toward sustainability, measurably improving their residents’ economic, social, and environmental well-being.

Several strong earthquakes around the world have resulted in a phenomenon called soil liquefaction, the seismic generation of excess porewater pressures and softening of granular soils, often to the point that they may not be able to support the foundations of buildings and other infrastructure.

Although individual anglers – people who fish recreationally – generally take small numbers of fish, collectively, a large number of them can have a substantial impact on the overall stock.

As the nation discusses repealing and replacing the Affordable Care Act, the National Academy of Medicine today released a publication on crosscutting priorities that provides a succinct blueprint to address challenges to Americans’ health and health care that span beyond debates over insurance coverage.

Mobilization of a rapid and robust clinical research program that explores whether investigational therapeutics and vaccines are safe and effective to combat the next infectious disease epidemic will depend on strengthening capacity in low-income countries for response and research, engaging people living in affected communities, and conducting safety trials before an epidemic hits, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Policymakers, employers, and educational institutions should take steps to strengthen the nation’s skilled technical workforce, says a new report from the National Academies of Sciences, Engineering, and Medicine.

While the Federal Motor Carrier Safety Administration’s (FMCSA) Safety Measurement System (SMS) used to identify commercial motor vehicle carriers at high risk for future crashes is conceptually sound, several features of its implementation need improvement, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

Nearly half of the nation’s spending on health care is driven by 5 percent of patients, and improving health outcomes and curbing spending in health care will require identifying who these high-needs patients are and providing coordinated services through successful care models that link medical, behavioral, and community resources, says a new National Academy of Medicine special publication.

Our ability to observe and predict severe weather events and other disasters has improved markedly over recent decades, yet this progress does not always translate into similar advances in the systems used in such circumstances to protect lives.

Policymakers’ efforts to reduce threats from improvised explosive devices (IEDs) should include greater oversight of precursor chemicals sold at the retail level – especially over the Internet – that terrorists, violent extremists, or criminals use to make homemade explosives, says a new report from the National Academies of Sciences, Engineering, and Medicine.

NASA, the National Oceanic and Atmospheric Administration (NOAA), and the United States Geological Survey (USGS) should implement a coordinated approach for their space-based environmental observations to further advance Earth science and applications for the next decade, says a new report by the National Academies of Sciences, Engineering, and Medicine.

The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine today announced grant awards for seven new projects totaling $5.3 million.

The U.S. Census Bureau should develop a detailed concept and implementation plan for an Annual Business Survey System (ABSS) to replace the current suite of largely separate annual economic surveys, says a new report by the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine recommends substantial changes to U.S. graduate education in science, technology, engineering, and mathematics (STEM) in order to meet the evolving needs of students, the scientific enterprise, and the nation.

The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine is collaborating with the Sea Grant Oil Spill Science Outreach Program to convene a series of workshops aimed at improving community preparedness for future oil spills.

A new report from the National Academies of Sciences, Engineering, and Medicine examines evidence on whether providing permanent supportive housing (PSH) – a combination of stable housing and supportive services -- to individuals who are experiencing homelessness improves their health.

The National Academy of Medicine today announced Kenneth Wells is the recipient of the 2018 Rhoda and Bernard Sarnat International Prize in Mental Health, for his work developing quality and outcomes approaches to psychiatry and mental health, fostering a generation of clinical investigators and mental health system leaders, and championing partnered, participatory research to advance equity for under-resourced populations.

A shift is needed in how science, technology, engineering, and mathematics (STEM) subjects are taught to students in grades K-12 who are learning English, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Centering science instruction around investigation and design can improve learning in middle and high schools and help students make sense of phenomena in the world around them.

While computational reproducibility in scientific research is generally expected when the original data and code are available, lack of ability to replicate a previous study -- or obtain consistent results looking at the same scientific question but with different data -- is more nuanced and occasionally can aid in the process of scientific discovery, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

The lack of supportive policies for families in the United States, such as paid parental leave, has serious implications for health equity, as it affects families’ overall health and financial stability, says a new report from the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine calls for a comprehensive national agenda to improve mental, emotional, and behavioral (MEB) health in children and youth. Despite advances in research, rates of depression, suicide and self-harm among young people have been increasing.

Whether a patient has a safe place to live or healthy food to eat has an important influence on their health, but such nonmedical social needs have not traditionally been addressed in routine health care visits.

U.S. colleges and universities should take a more intentional, inclusive, and evidence-based approach to mentoring students in STEMM (science, technology, engineering, mathematics, and medicine) – a shift that could engage and help retain a broader group of students in these fields, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Medicine regulatory authorities — including the U.S. Food and Drug Administration (FDA) — should strengthen cooperation with other countries’ regulators to ensure the quality, safety, and efficacy of medicines, says a new report from the National Academies of Sciences, Engineering, and Medicine.