Structural biology: a century-long journey into an unseen world

© Institute of Materials, Minerals and Mining 2015.When the first atomic structures of salt crystals were determined by the Braggs in 1912–1913, the analytical power of X-ray crystallography was immediately evident. Within a few decades the technique was being applied to the more complex molecules of chemistry and biology and is rightly regarded as the foundation stone of structural biology, a field that emerged in the 1950s when X-ray diffraction analysis revealed the atomic architecture of DNA and protein molecules. Since then the toolbox of structural biology has been augmented by other physical techniques, including nuclear magnetic resonance spectroscopy, electron microscopy, and solution scattering of X-rays and neutrons. Together these have transformed our understanding of the molecular basis of life. Here I review the major and most recent developments in structural biology that have brought us to the threshold of a landscape of astonishing molecular complexity

Open access: brave new world requires bravery

The year 2012 heralded significant developments in open access (OA) that impacted the relationships between the major stakeholders in scholarly publishing: researchers, funders, publishers and governments. In the UK, the clear preference for a gold OA policy enunciated by the government-backed Finch Report is now being implemented by the research councils. Although the policy has been modified to include green routes to OA publishing, arguments continue about the optimal route to a system of open access that can work on a global scale. Resolution of these disputes will require courage and imagination

Measuring Symbol and Icon Characteristics: Norms for Concreteness, Complexity, Meaningfulness, Familiarity, and Semantic Distance for 239 Symbols

This paper provides rating norms for a set of symbols and icons selected from a wide variety of sources. These ratings enable the effects of symbol characteristics on user performance to be systematically investigated. The symbol characteristics that have been quantified are considered to be of central relevance to symbol usability research and include concreteness, complexity, meaningfulness, familiarity, and semantic distance. The interrelationships between each of these dimensions is examined and the importance of using normative ratings for experimental research is discussed

THREATS TO GOLDEN-FLOWERED CAMELLIAS ALONG HON GIAO PASS

The identification, documentation, and discussion of the main threats affecting the golden-flowered Camellia species endemic to Hon Giao Pass are discussed. Observations, published literature, and collations of data accumulated from field trips throughout Vietnam since 1999 are analyzed and researched for the preparation of the article. The major anthropogenic risk factors affecting the golden-flowered Camellia species and their habitats on the Dalat Plateau and along the Hon Giao Pass are named and reviewed. These risk factors include habitat loss due to population growth, logging, habitat fragmentation and degradation, poaching, collection of wild plant species, fire, and the construction of dams and their associated water impoundments

Surface heat flux determination: An analytical and experimental study using a single embedded thermocouple

A numerical method by which data from a single embedded thermocouple can be used to predict the transient thermal environment for both high- and low-conductivity materials is described. The results of an investigation performed to verify the method clearly demonstrate that accurate, transient, surface heating conditions can be obtained from a thermocouple l.016 centimeters from the heating surface in a low-conductivity material. Space shuttle orbiter thermal protection system materials having temperature- and pressure-dependent properties, and typical orbiter entry heating conditions were used to verify the accuracy of the analytical procedure. Analytically generated, as well as experimental, data were used to compare predicted and measured surface temperatures

An efficiency study on obtaining the minimum weight of a thermal protection system

Three minimizing techniques are evaluated to determine the most efficient method for minimizing the weight of a thermal protection system and for reducing computer usage time. The methods used (numerical optimization and nonlinear least squares) for solving the minimum-weight problem involving more than one material and more than one constraint are discussed. In addition, the one material and one constraint problem is discussed

The estimation of pointing angle and normalized surface scattering cross section from GEOS-3 radar altimeter measurements

The statistical error of the pointing angle estimation technique is determined as a function of the effective receiver signal to noise ratio. Other sources of error are addressed and evaluated with inadequate calibration being of major concern. The impact of pointing error on the computation of normalized surface scattering cross section (sigma) from radar and the waveform attitude induced altitude bias is considered and quantitative results are presented. Pointing angle and sigma processing algorithms are presented along with some initial data. The intensive mode clean vs. clutter AGC calibration problem is analytically resolved. The use clutter AGC data in the intensive mode is confirmed as the correct calibration set for the sigma computations

Crystal structure of the 3C protease from South African Territories type 2 foot-and-mouth disease virus

The replication of foot-and-mouth disease virus (FMDV) is dependent on the virus-encoded 3C protease (3Cpro). As in other picornaviruses, 3Cpro performs most of the proteolytic processing of the polyprotein expressed from the single open reading frame in the RNA genome of the virus. Previous work revealed that the 3Cpro from serotype A – one of the seven serotypes of FMDV – adopts a trypsin-like fold. Phylogenetically the FMDV serotypes are grouped into two clusters, with O, A, C, and Asia 1 in one, and the three South African Territories serotypes, (SAT-1, SAT-2 and SAT-3) in another. We report here the cloning, expression and purification of 3C proteases from four SAT serotype viruses (SAT2/GHA/8/91, SAT1/NIG/5/81, SAT1/UGA/1/97, and SAT2/ZIM/7/83) and the crystal structure at 3.2 Å resolution of 3Cpro from SAT2/GHA/8/91)

Effective thermal conductivity determination for low-density insulating materials

That nonlinear least squares can be used to determine effective thermal conductivity was demonstrated, and a method for assessing the relative error associated with these predicted values was provided. The differences between dynamic and static determination of effective thermal conductivity of low-density materials that transfer heat by a combination of conduction, convection, and radiation were discussed