Supramolecular parallel beta-sheet and amyloid-like fibril forming peptides using delta-aminovaleric acid residue

Four terminally blocked tripeptides containing delta-aminovaleric acid residue self-assemble to form supramolecular beta-sheet structures as are revealed from their FT-IR data. Single crystal X-ray diffraction studies of two representative peptides also show that they form parallel beta-sheet structures. Self-aggregation of these beta-sheet forming peptides leads to the formation of fibrillar structures, as is evident from scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images. These peptide fibrils bind to a physiological dye, Congo red and exhibit a typical green-gold birefringence under polarized light, showing close resemblance to neurodegenerative disease causing amyloid fibrils. (c) 2005 Elsevier Ltd. All rights reserved.

Morphology of polymer networks formed in the chiral and non chiral phases of an anti-ferroelectric liquid crystal

We introduced photo-polymer networks into the various liquid crystalline phases of the antiferroelectric liquid crystal AS612 and studied the effects of these networks by measuring the temperature dependence of the Bragg wavelengths selectively reflected. After polymerization, the decrease in Bragg wavelengths with respect to the original values is consistent with a shorter helical pitch due to polymer network shrinkage. Also, by removing the liquid crystalline material, we are able to image the residual polymer network using scanning electron microscopy and polarized light microscopy. The polymer strands are a few microns thick and the networks show both chiral and non-chiral features.

Cloud information content analysis of multi-angular measurements in the oxygen A-band: application to 3MI and MSPI

The vertical distribution of cloud cover has a significant impact on a large number of meteorological and climatic processes. Cloud top altitude and cloud geometrical thickness are then essential. Previous studies established the possibility of retrieving those parameters from multi-angular oxygen A-band measurements. Here we perform a study and comparison of the performances of future instruments. The 3MI (Multi-angle, Multi-channel and Multi-polarization Imager) instrument developed by EUMETSAT, which is an extension of the POLDER/PARASOL instrument, and MSPI (Multi-angles Spectro-Polarimetric Imager) develoloped by NASA's Jet Propulsion Laboratory will measure total and polarized light reflected by the Earth's atmosphere–surface system in several spectral bands (from UV to SWIR) and several viewing geometries. Those instruments should provide opportunities to observe the links between the cloud structures and the anisotropy of the reflected solar radiation into space. Specific algorithms will need be developed in order to take advantage of the new capabilities of this instrument. However, prior to this effort, we need to understand, through a theoretical Shannon information content analysis, the limits and advantages of these new instruments for retrieving liquid and ice cloud properties, and especially, in this study, the amount of information coming from the A-Band channel on the cloud top altitude (CTOP) and geometrical thickness (CGT). We compare the information content of 3MI A-Band in two configurations and that of MSPI. Quantitative information content estimates show that the retrieval of CTOP with a high accuracy is possible in almost all cases investigated. The retrieval of CGT seems less easy but possible for optically thick clouds above a black surface, at least when CGT > 1–2 km.

Using coordinated observations in polarized white light and Faraday rotation to probe the spatial position and magnetic field of an interplanetary sheath

Coronal mass ejections (CMEs) can be continuously tracked through a large portion of the inner heliosphere by direct imaging in visible and radio wavebands. White light (WL) signatures of solar wind transients, such as CMEs, result from Thomson scattering of sunlight by free electrons and therefore depend on both viewing geometry and electron density. The Faraday rotation (FR) of radio waves from extragalactic pulsars and quasars, which arises due to the presence of such solar wind features, depends on the line-of-sight magnetic field component B ∥ and the electron density. To understand coordinated WL and FR observations of CMEs, we perform forward magnetohydrodynamic modeling of an Earth-directed shock and synthesize the signatures that would be remotely sensed at a number of widely distributed vantage points in the inner heliosphere. Removal of the background solar wind contribution reveals the shock-associated enhancements in WL and FR. While the efficiency of Thomson scattering depends on scattering angle, WL radiance I decreases with heliocentric distance r roughly according to the expression Ir –3. The sheath region downstream of the Earth-directed shock is well viewed from the L4 and L5 Lagrangian points, demonstrating the benefits of these points in terms of space weather forecasting. The spatial position of the main scattering site r sheath and the mass of plasma at that position M sheath can be inferred from the polarization of the shock-associated enhancement in WL radiance. From the FR measurements, the local B ∥sheath at r sheath can then be estimated. Simultaneous observations in polarized WL and FR can not only be used to detect CMEs, but also to diagnose their plasma and magnetic field properties.

Molecular modelling studies of binding of DACD derivatives into G-Quadruplex DNA: comparison of force field and quantum polarized ligand docking methods

The DNA G-qadruplexes are one of the targets being actively explored for anti-cancer therapy by inhibiting them through small molecules. This computational study was conducted to predict the binding strengths and orientations of a set of novel dimethyl-amino-ethyl-acridine (DACA) analogues that are designed and synthesized in our laboratory, but did not diffract in Synchrotron light.Thecrystal structure of DNA G-Quadruplex(TGGGGT)4(PDB: 1O0K) was used as target for their binding properties in our studies.We used both the force field (FF) and QM/MM derived atomic charge schemes simultaneously for comparing the predictions of drug binding modes and their energetics. This study evaluates the comparative performance of fixed point charge based Glide XP docking and the quantum polarized ligand docking schemes. These results will provide insights on the effects of including or ignoring the drug-receptor interfacial polarization events in molecular docking simulations, which in turn, will aid the rational selection of computational methods at different levels of theory in future drug design programs. Plenty of molecular modelling tools and methods currently exist for modelling drug-receptor or protein-protein, or DNA-protein interactionssat different levels of complexities.Yet, the capasity of such tools to describevarious physico-chemical propertiesmore accuratelyis the next step ahead in currentresearch.Especially, the usage of most accurate methods in quantum mechanics(QM) is severely restricted by theirtedious nature. Though the usage of massively parallel super computing environments resulted in a tremendous improvement in molecular mechanics (MM) calculations like molecular dynamics,they are still capable of dealing with only a couple of tens to hundreds of atoms for QM methods. One such efficient strategy that utilizes thepowers of both MM and QM are the QM/MM hybrid methods. Lately, attempts have been directed towards the goal of deploying several different QM methods for betterment of force field based simulations, but with practical restrictions in place. One of such methods utilizes the inclusion of charge polarization events at the drug-receptor interface, that is not explicitly present in the MM FF.

Polarized hadro- and photoproduction of heavy quarks in NLO QCD

We present the first calculation of the complete NLO QCD corrections to the production of heavy flavors with longitudinally polarized hadrons. This reaction can be used at RHIC to extract the gluon helicity density and may shed light on the "heavy quark enigma". The theoretical uncertainties are briefly discussed.

Displacement of Zn through acidic light-textured soils

In order to gain understanding of the movement of pollutant metals in soil. the chemical mechanisms involved in the transport of zinc were studied. The displacement of zinc through mixtures of sand and cation exchange resin was measured to validate the methods used for soil. With cation exchange capacities of 2.5 and 5.0 cmol(c) kg(-1). 5.6 and 8.4 pore volumes of 10 mM CaCl2, respectively, were required to displace a pulse of ZnCl2. A simple Burns-type model (Wineglass) using an adsorption coefficient (K-d) determined by fitting a straight line relationship to an adsorption isotherm gave a good fit to the data (K-d=0.73 and 1.29 ml g(-1), respectively). Surface and subsurface samples of an acidic sandy loam (organic matter 4.7 and 1.0%. cation exchange capacity (CEC) 11.8 and 6.1 cmol(c) kg(-1) respectively) were leached with 10 mM calcium chloride. nitrate and perchlorate. With chloride. the zinc pulse was displaced after 25 and 5 pore volumes, respectively. The Kd values were 6.1 and 2.0 ml g(-1). but are based on linear relationships fitted to isotherms which are both curved and show hysteresis. Thus. a simple model has limited value although it does give a general indication of rate of displacement. Leaching with chloride and perchlorate gave similar displacement and Kd values, but slower movement occurred with nitrate in both soil samples (35 and 7 pore volumes, respectively) which reflected higher Kd values when the isotherms were measured using this anion (7.7 and 2.8 ml g(-1) respectively). Although pH values were a little hi-her with nitrate in the leachates, the differences were insufficient to suggest that this increased the CEC enough to cause the delay. No increases in pH occurred with nitrate in the isotherm experiments. Geochem was used to calculate the proportions of Zn complexed with the three anions and with fulvic acid determined from measurements of dissolved organic matter. In all cases, more than 91% of the Zn was present as Zn2+ and there were only minor differences between the anions. Thus, there is an unexplained factor associated with the greater adsorption of Zn in the presence of nitrate. Because as little as five pore volumes of solution displaced Zn through the subsurface soil, contamination of ground waters may be a hazard where Zn is entering a light-textured soil, particularly where soil salinity is increased. Reductions in organic matter content due to cultivation will increase the hazard. (C) 2004 Elsevier B.V. All rights reserved.

Rethinking the powers of truth commissions in light of the ICC statute

The Rome Statute of the International Criminal Court (ICC) is silent on the issue of national truth commissions. How the ICC might treat these bodies and the information they may hold is uncertain. The overlapping nature of the investigations likely to be carried out by the ICC and future truth-seeking bodies may, however, give rise to areas of tension, particularly where truth commissions hold confidential or self-incriminating information. This article questions whether the traditional truth-seeking powers to grant confidentiality and compel the provision of self-incriminating statements are compatible with the prosecutorial framework of the ICC. It considers how such information is likely to be dealt with by the ICC and analyses whether effective truth seeking can be carried out in the absence of such powers.

Solar change and climate: an update in the light of the current exceptional solar minimum

Solar outputs during the current solar minimum are setting record low values for the space age. Evidence is here reviewed that this is part of a decline in solar activity from a grand solar maximum and that the Sun has returned to a state that last prevailed in 1924. Recent research into what this means, and does not mean, for climate change is reviewed.

Stray light analysis of SALEX instrument

Discrepancies between recent global earth albedo anomaly data obtained from the climate models, space and ground observations call for a new and better earth reflectance measurement technique. The SALEX (Space Ashen Light Explorer) instrument is a space-based visible and IR instrument for precise estimation of the global earth albedo by measuring the ashen light reflected off the shadowy side of the Moon from the low earth orbit. The instrument consists of a conventional 2-mirror telescope, a pair of a 3-mirror visible imager and an IR bolometer. The performance of this unique multi-channel optical system is sensitive to the stray light contamination due to the complex optical train incorporating several reflecting and refracting elements, associated mounts and the payload mechanical enclosure. This could be further aggravated by the very bright and extended observation target (i.e. the Moon). In this paper, we report the details of extensive stray light analysis including ghosts and cross-talks, leading to the optimum set of stray light precautions for the highest signal-to-noise ratio attainable.

The colour, light and contrast manual - designing and managing inclusive built environments

Endorsed by the Society of Light and Lighting, this practical book offers comprehensive guidance on how colour, light and contrast can be incorporated within buildings to enhance their usability. The book provides state-of-the-art, clear guidance as well as a valuable information source for busy professionals involved in the design or management of new and existing environments. The ways colour, light and contrast are used within built environments are critical in determining how people interact with the space, and how confident, safe, and secure they will feel when doing so. They also have a major influence on a person’s sense of well-being and their ability to use the environment independently and without undue effort. Understanding how to use colour and contrast and how they are influenced by both natural and artificial lighting is vital for all those involved in the design and management of the environments and spaces we all use. In recent years there has been a considerable amount of work undertaken to further our understanding of how colour, light and contrast affect emotion and sensory abilities, and how they can assist or hinder people in their everyday lives. Other publications consider these issues individually but The Colour, Light and Contrast Manual: designing and managing inclusive built environments draws knowledge and information together to produce a unique, comprehensive and informative guide to how the three elements can work together to improve the design and management of environments for us all.

Forward modelling to determine the observational signatures of white-light imaging and interplanetary scintillation for the propagation of an interplanetary shock in the ecliptic plane

Recent coordinated observations of interplanetary scintillation (IPS) from the EISCAT, MERLIN, and STELab, and stereoscopic white-light imaging from the two heliospheric imagers (HIs) onboard the twin STEREO spacecraft are significant to continuously track the propagation and evolution of solar eruptions throughout interplanetary space. In order to obtain a better understanding of the observational signatures in these two remote-sensing techniques, the magnetohydrodynamics of the macro-scale interplanetary disturbance and the radio-wave scattering of the micro-scale electron-density fluctuation are coupled and investigated using a newly constructed multi-scale numerical model. This model is then applied to a case of an interplanetary shock propagation within the ecliptic plane. The shock could be nearly invisible to an HI, once entering the Thomson-scattering sphere of the HI. The asymmetry in the optical images between the western and eastern HIs suggests the shock propagation off the Sun–Earth line. Meanwhile, an IPS signal, strongly dependent on the local electron density, is insensitive to the density cavity far downstream of the shock front. When this cavity (or the shock nose) is cut through by an IPS ray-path, a single speed component at the flank (or the nose) of the shock can be recorded; when an IPS ray-path penetrates the sheath between the shock nose and this cavity, two speed components at the sheath and flank can be detected. Moreover, once a shock front touches an IPS ray-path, the derived position and speed at the irregularity source of this IPS signal, together with an assumption of a radial and constant propagation of the shock, can be used to estimate the later appearance of the shock front in the elongation of the HI field of view. The results of synthetic measurements from forward modelling are helpful in inferring the in-situ properties of coronal mass ejection from real observational data via an inverse approach.

Changes in light intensity during the rearing period can influence egg production in domestic fowl

1. A total of 240 Shaver White and 240 ISA Brown pullets that had been reared in multi-bird cages on a 10-h photoperiod, and maintained at a light intensity of 3 or 25 lux, or changed from 3 to 25 lux or from 25 to 3 lux at 9 or 16 weeks of age, were moved into individual-bird cages at 20 weeks and transferred to 15-h photoperiods at 25 lux. 2. In both breeds, birds transferred from 3 to 25 lux at 16 or 20 weeks laid significantly more eggs than birds maintained on the brighter intensity from one day or increased to it at 9 weeks. 3. Mean egg weight, shell deformation, albumen height, feed intake and body weight gain in lay were not significantly affected by the light intensity treatments during the rearing period. There was, however, a small, but significant, negative correlation of egg numbers with mean egg weight, although this only partially explained the difference in egg numbers. The differences in egg production were unrelated to rate of sexual maturation.