Deliberately Losing Control of C−H Activation Processes in the Design of Small-Molecule-Fragment Arrays Targeting Peroxisomal Metabolism

Combined photochemical arylation, “nuisance effect” (S_NAr) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein–ligand structure determination. Reactions were deliberately allowed to run “out of control” in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with S_NAr processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified.     

Multiplex PCR system to track authorized and unauthorized genetically modified soybean events in food and feed

A diverse range of genetic elements has been used to develop genetically modified organisms (GMOs) over the last 18 years. Screening methods that target few elements, such as the Cauliflower Mosaic Virus 35S promoter (P-35S) and Agrobacterium tumefaciens nopaline terminator (T-nos), are not sufficient to screen GMOs. In the present study, a multiplex PCR system for all globally commercialized GM soybean events was developed to easily trace the events. For this purpose, screening elements of 24 GM soybean events were investigated and 9 screening targets were selected and divided into three individual triplex PCR systems: P-35S, ribulose-1,5-bisphosphate carboxylase small subunit promoter of Arabidopsis thaliana, T-nos, T-35S, pea E9 terminator, open reading frame 23 terminator of A. tumefaciens, proteinase inhibitor II terminator of potato, acetohydroxy acid synthase large subunit terminator of A. thaliana, and the revealed 3′ flanking sequences of DP-305423-1. The specificity of the assays was confirmed using thirteen GM soybean events as the respective positive/negative controls. The limit of detection of each multiplex set, as determined using certified reference materials of specific GM events, ranged from 0.03 to 0.5%, depending upon target. Furthermore, 26 food samples that contained soybean ingredients, which were purchased from the USA, China, Japan, and Korea, were analyzed, 17 of which contained one or more GM soybean events. These results suggest that the developed screening method can be used to efficiently track and identify 24 GM soybean events in food and feed.     

Experimental evidence of a relationship between monomer plasma residence time and carboxyl group retention in acrylic acid plasma polymers

Decreasing carboxyl retention in deposits from the glow region of an acrylic acid plasma was measured by X-ray photoelectron spectroscopy and chemical derivatisation as the collection distance from the monomer vapour inlet was increased. Volatilisation of plasma polymerised acrylic acid was detected after trifluoroethanol derivatisation; this is correlated with evaporation of low molecular weight components observed previously.     

Specification,Verification and Prototyping of an Optimized Compiler

This paper generalizes an algebraic method for the design of a correct compiler to tackle specification and verification of an optimized compiler. The main optimization issues of concern here include the use of existing contents of registers where possible and the identification of common expressions. A register table is introduced in the compiling specification predicates to map each register to an expression whose value is held by it. We define different kinds of predicates to specify compilation of programs, expressions and Boolean tests. A set of theorems relating to these predicates, acting as a correct compiling specification, are presented and an example proof within the refinement algebra of the programming language is given. Based on these theorems, a prototype compiler in Prolog is produced.     

Free-Edge and Ply Cracking Effect in Angle-Ply Laminated Composites Subjected to In-Plane Loads

This paper presents a semianalytical method for the prediction of interlaminar stresses and displacements near the free edges and ply cracks in general angle-ply laminates subjected to biaxial extensions and/or in plane shear deformation. The method is based on a state space representation of the three-dimensional equations of elasticity. Numerical solutions are obtained by using layer refinement in the through thickness direction and Fourier series expansion in the other directions. By this approach, an angle-ply laminate may be composed of an arbitrary number of monoclinic layers and each layer may have different material property and thickness. This method guarantees continuous fields of all interlaminar stresses across interfaces between material layers. Numerical results are compared with those obtained from other methods. It is found that the theory provides a satisfactory approximation to the stress singularities near the free edges and ply cracks. Numerical solutions for antisymmetric laminates under extension and general laminates under shearing are new in the literature and can be used as benchmarks for validating new models.     

Recovering spectral data from natural scenes with an RGB digital camera and colored filters

Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007     

Normal form approach to compiler design

This paper demonstrates how reduction to normal form can help in the design of a correct compiler for Dijkstra's guarded command language. The compilation strategy is to transform a source program, by a series of algebraic manipulations, into a normal form that describes the behaviour of a stored-program computer. Each transformation eliminates high-level language constructs in favour of lower-level constructs. The correctness of the compiler follows from the correctness of each of the algebraic transformations.     

Eddy current measurements of electrical conductivity and magnetic permeability of porous metals

This paper presents a method, which simultaneously estimates the electrical conductivity and magnetic permeability of porous metals. Porous Cu and Fe manufactured by the lost carbonate sintering process have been tested. An air-cored solenoid coil was designed for the measurements of rod-shaped samples when inserted coaxially with the coil. It was theoretically found that the phase-frequency response of the normalised eddy current signal of the coil is virtually independent of the radius, electrical conductivity and magnetic permeability of the test samples. For non-magnetic, conductive porous Cu, the electrical conductivity was measured with a calibration curve of the coil relating the impedance change and the electrical conductivity of the sample. For magnetic porous Fe, the imaginary part of the signal at the lowest frequencies can be used to estimate the permeability. The measured conductivity values of the porous Cu are shown in the paper in comparison with that of bulk materials with known conductivity. The measured permeability values of the porous Fe are given and the sample-length effect on the measurements is also discussed.     

Static and dynamic studies of phase composition in a polydisperse system

We have conducted a study of the phase compositions of a ternary solution containing dextran/polyethylene glycol (PEG)/water using UV-visible spectrometry to study the equilibrium behaviour and confocal microscopy to study the dynamic behaviour observed when the system undergoes phase separation driven by the loss of water. Such a study of phase compositions using confocal microscopy is a new development of the technique. In the static experiments, we find a cloud curve, which lies above the coexistence curve on the PEG rich side of the phase diagram, this is found to be in qualitative agreement with calculations of the phase behaviour for a model polydisperse system. In the dynamic experiments, we are able to measure the phase composition using confocal microscopy in the late stages of separation. Here, the compositions lie well inside the coexistence curve at lower drying rates but converge with it at higher drying rates. This is linked to a change in phase morphology: at low rates, a droplet morphology is observed throughout the process whilst at high drying rates a gross phase separation into two layers is observed to occur even at the earliest times probed by the experiment.