Comparison of four serological tests to determine the CagA or VacA status of Helicobacter pylori strains

We compared four tests for antibodies to CagA or VacA, HelicoBlot 2. 0, RIDA Blot Helicobacter, CHIRON RIBA H. pylori SIA, and an enzyme-linked immunosorbent assay using recombinant CagA. Immunoblot assays were accurate for determining Helicobacter pylori status but poor for determining CagA or VacA status (accuracy, 66 to 80% for CagA status and 34 to 67% for VacA status). None can be recommended for determining CagA or VacA status.     

Generalized honeycomb torus is Hamiltonian

Generalized honeycomb torus is a candidate for interconnection network architectures, which includes honeycomb torus, honeycomb rectangular torus, and honeycomb parallelogramic torus as special cases. Existence of Hamiltonian cycle is a basic requirement for interconnection networks since it helps map a “token ring” parallel algorithm onto the associated network in an efficient way. Cho and Hsu [Inform. Process. Lett. 86 (4) (2003) 185-190] speculated that every generalized honeycomb torus is Hamiltonian. In this paper, we have proved this conjecture.     

Copper-binding compounds from Methylosinus trichosporium OB3b

Two copper-binding compounds/cofactors (CBCs) were isolated from the spent media of both the wild type and a constitutive soluble methane monooxygenase (sMMOC) mutant, PP319 (P. A. Phelps et al., Appl. Environ. Microbiol. 58:3701-3708, 1992), of Methylosinus trichosporium OB3b. Both CBCs are small polypeptides with molecular masses of 1,218 and 779 Da for CBC-L1 and CBC-L2, respectively. The amino acid sequence of CBC-L1 is S?MYPGS?M, and that of CBC-L2 is SPMP?S. Copper-free CBCs showed absorption maxima at 204, 275, 333, and 356 with shoulders at 222 and 400 nm. Copper-containing CBCs showed a broad absorption maximum at 245 nm. The low-temperature electron paramagnetic resonance (EPR) spectra of copper-containing CBC-L1 showed the presence of a copper center with an EPR splitting constant between those of type 1 and type 2 copper centers (g = 2.087, g = 2.42 G, A = 128 G). The EPR spectrum of CBC-L2 was more complex and showed two spectrally distinct copper centers. One signal can be attributed to a type 2 Cu2+ center (g = 2.073, g = 2.324 G, A = 144 G) which could be saturated at higher powers, while the second shows a broad, nearly isotropic signal near g = 2.063. In wild-type strains, the concentrations of CBCs in the spent media were highest in cells expressing the pMMO and stressed for copper. In contrast to wild-type strains, high concentrations of CBCs were observed in the extracellular fraction of the sMMOC mutants PP319 and PP359 regardless of the copper concentration in the culture medium.     

Real-time camera tracking using sports pitch markings

When broadcasting sports events such as football, it is useful to be able to place virtual annotations on the pitch, to indicate things such as distances between players and the goal, or whether a player is offside. This requires the camera position, orientation, and focal length to be estimated in real time, so that the graphics can be rendered to match the camera view. Whilst this can be achieved by using sensors on the camera mount and lens, they can be impractical or expensive to install, and often the broadcaster only has access to the video feed itself. This paper presents a method for computing the position, orientation and focal length of a camera in real time, using image analysis. The method uses markings on the pitch, such as arcs and lines, to compute the camera pose. A novel feature of the method is the use of multiple images to improve the accuracy of the camera position estimate. A means of automatically initialising the tracking process is also presented, which makes use of a modified form of Hough transform. The paper shows how a carefully chosen set of algorithms can provide fast, robust and accurate tracking for this real-world application.     

Influence of the Silicon Substrate on Defect Formation in MCT Grown on II-VI Buffered Si Using a Combined Molecular Beam Epitaxy/Metal Organic Vapor Phase Epitaxy Technique

II-VI buffer layers grown by molecular beam epitaxy (MBE) onto silicon exhibit a uniform, slightly faceted surface morphology. However, a number of surface defects are apparent and these are amplified by the subsequent growth of mercury cadmium telluride (MCT) by metal organic vapor phase epitaxy. Some of these defects have been traced to polishing damage present within the silicon substrate. A range of analytical techniques, including x-ray topography, have been used to track the defects from the substrate through to the buffer layer and into the MCT. Defects of this type will cause dead elements in the infrared focal plane arrays and will be a major cause of low operabilities.     

Extraction and analysis of forensic document examiner features used for writer identification

In this paper we present a study of structural features of handwriting extracted from three characters “d”, “y”, and “f” and grapheme “th”. The features used are based on the standard features used by forensic document examiners. The process of feature extraction is presented along with the results. Analysis of the usefulness of features was conducted via searching the optimal feature sets using the wrapper method. A neural network was used as a classifier and a genetic algorithm was used to search for optimal feature sets. It is shown that most of the structural micro features studied, do possess discriminative power, which justifies their use in forensic analysis of handwriting. The results also show that the grapheme possessed significantly higher discriminating power than any of the three single characters studied, which supports the opinion that a character form is affected by its adjacent characters.     

Anti-symmetric motion of a pre-stressed incompressible elastic layer near shear resonance

A two-dimensional model is derived for anti-symmetric motion in the vicinity of the shear resonance frequencies in a pre-stressed incompressible elastic plate. The method of asymptotic integration is used and a second-order solution, for infinitesimal displacement components and incremental pressure, is obtained in terms of the long-wave amplitude. The leading-order hyperbolic governing equation for the long-wave amplitude is observed to be not wave-like for certain pre-stressed states, with time and one of the in-plane spatial variables swapping roles. This phenomenon is shown to be intimately related to the possible existence of negative group velocity at low wave number, i.e. in the vicinity of shear resonance frequencies.     

Quantitative characterization of three-dimensional damage evolution in a wrought Al-alloy under tension and compression

Three-dimensional (3-D) microstructural damage due to cracking of Fe-rich intermetallic particles is quantitatively characterized as a function of strain under compression and tension in an Al-Mg-Si base wrought alloy. The 3-D number fraction of damaged (cracked) particles, their average volume, average surface area, and shape factor are estimated at different strain levels for deformation under uniaxial tension and compression. It is shown that, depending on the type of loading, loading direction, particle shape, and microstructural anisotropy, the two-dimensional (2-D) number fraction of the damaged particles can be smaller or larger than the corresponding true 3-D number fraction. Under uniaxial tension, the average volume and surface area of cracked particles decrease with the strain. However, the average volume and surface area of the cracked particles increase with the increase in the compressive strain, implying that more and more larger elongated particles crack at higher and higher stress levels, which is contrary to the predictions of the existing particle cracking theories. In this alloy, the damage development due to particle cracking is intimately coupled with the particle rotations. The differences in the damage evolution under tension and compression are explained on the basis of the differences in the particle rotation tendencies under these two loading conditions.     

Sources and timing of anthropogenic pollution in the Ensenada de San Simon (inner Ria de Vigo), Galicia, NW Spain: an application of mixture-modelling and nonlinear optimization to recent sedimentation

The Ensenada de San Simon is the inner part of the Ria de Vigo, one of the major mesotidal rias of the Galician coast, NW Spain. The geochemistry of its bottom sediments can be accounted for in terms of both natural and anthropogenic sources. Mixture-modelling enables much of the Cr, Ni, V, Cu, Pb and Zn concentrations of the bottom and subaqueous sediments to be explained by sediment input from the river systems and faecal matter from manmade mussel rafts. The compositions and relative contributions of additional, unknown, sources of anomalous heavy-metal concentrations are quantified using constrained nonlinear optimization. The pattern of metal enrichment is attributed to: material carried in solution and suspension in marine water entering the Ensenada from the polluted industrial areas of the adjacent Ria de Vigo; wind-borne urban dusts and/or vehicular emissions from the surrounding network of roads and a motorway road-bridge over the Estrecho de Rande; industrial and agricultural pollution from the R. Redondela; and waste from a former ceramics factory near the mouth of the combined R. Oitaben and R. Verdugo. Using (137)Cs dating, it is suggested that heavy metal build-up in the sediments since the late 1970s followed development of inshore fisheries and introduction of the mussel rafts (ca. 1960) and increasing industrialisation.     

Influence of autochthonous dissolved organic carbon and nutrient limitation on alachlor biotransformation in aerobic aquatic systems

Much work has suggested that the rate of attenuation of water-soluble organic contaminants in aerobic aquatic systems is dependent on the level of secondary nutrients in the water column. For example, the decay rate of alachlor, a common herbicide, was over 10 times higher under hypereutrophic compared with oligotrophic water conditions. It has been presumed that higher water column nutrient levels produce larger microbial communities, resulting in higher rates of alachlor cometabolism. However, most earlier field studies only assessed alachlor fate in systems with full light exposure (FLE). Therefore, new experiments were performed to assess how variations in light level affect alachlor cometabolism in such systems. Twelve tank mesocosms were maintained using identical nitrogen (N) and phosphorus (P) supply conditions: four units with full light exposure (100% FLE), four with partial shading (19.3% FLE), and four with near complete shading (0.5% FLE). Alachlor half-lives were found to vary broadly, from 50 to 60 days in higher light units to > 180 days in the 0.5% FLE units. Nutrient analysis indicated that the low light units were severely carbon (C)-limited for microbial decomposition, whereas the other units had excess C relative to N and P. Apparently, reduced light levels cause decreased production of bioavailable C for decomposition, which significantly reduces alachlor cometabolism. The data suggest that water column nutrient levels only correlate with the alachlor decay rate when light levels are high, and that the biodegradable carbon supply must be considered when the fate of water-soluble contaminants in aerobic aquatic systems is assessed.