A gene for autosomal recessive limb-girdle muscular dystrophy maps to chromosome 2p

The limb-girdle muscular dystrophies are a clinically and genetically heterogeneous group of disorders. We have studied two large inbred families of different ethnic origin and excluded linkage to LGMD2 on chromosome 15q and SCARMD on chromosome 13. Proceeding to a genomic linkage search, we have now identified linkage to markers D2S134 and D2S136 on chromosome 2p (maximum lod score 3.57 at zero recombination). The phenotype in the two families was similar, with onset in the pelvic girdle musculature in the late teens and usually relatively slow progression. This work identifies a second locus for autosomal recessive limb-girdle muscular dystrophy.     

Elimination of the sidewall defects in selective epitaxial growth(SEG) of silicon for a dielectric isolation technology

Selective epitaxial growth (SEG) of silicon has not had widespread use as a dielectric isolation technology due to the near sidewall defects at the SiO₂/Si interface. These defects are located in the first 1-2 μm of the SEG/sidewall SiO₂ interface. Diode junctions intersecting the sidewall and 5 μm removed from the sidewall were fabricated in SEG material using thermally grown silicon dioxide (OX) and thermally nitrided thermal silicon dioxide (NOX) as the field insulating mask. Averaged over 16 devices of each type, diodes fabricated with NOX had much better low current I-V characteristics and minimum ideality factors (1.03) than diodes fabricated with OX field oxides (1.23). Junctions intersecting the NOX field insulator had nearly identical characteristics to bulk SEG     

The Management and Processing of Network Performance Information

The performance of communications networks can be monitored intrusively by transmitting test packets on the network links being tested. The delays experienced by these test packets and the number of test packets lost or duplicated may provide an indication of the performance of the links being monitored. Intrusive network monitoring, even at modest sampling rates, generates a significantly large amount of primitive data. This data needs to be summarised appropriately to address the required network performance analysis operations. These operations are generally iterative in nature, where the results of initial processing and analysis generate requirements for further processing and analysis. This paper describes the architecture of a database that can assist in efficient analysis of network performance by reusing the information derived at various stages.     

A simple process to produce a high quality silicon surface prior toselective epitaxial growth

A simple and low-cost process was devised to eliminate etch damage resulting from oxide etching on the seed-hole surface prior to selective epitaxial growth (SEG) of silicon. The process consists of a low power C ₂F₆ RIE step which was performed right after the oxide etch step in the same etch reactor. The use of this step excluded the need of a conventional sacrificial oxide to remove damaged silicon regions and residual polymers. The n-p diodes resulting from n-type SEG grown on p-type substrate were used to evaluate the quality of the silicon surface prior to SEG     

Low cycle fatigue of as-HIP and HIP+forged rené 95

The continuous cycling and hold time low cycle fatigue properties of the Ni base superalloy René 95 were studied at 649°C using powder products (−60 mesh) in the as-HIP and HIP + forged conditions. It was shown that cracks were initiated by pores, by ceramic particles and by a classical stage I mechanism for both materials and for both cycle characters. For the continuously cycled as-HIP material, deformation was restricted to well defined bands at low strains and became homogeneous as the strain level increased. The total energy to fracture increased abruptly in the low strain regime and this was also reflected by a break in the Coffin-Manson plot. In all cases cracks initiated at pores. The hold time specimens exhibited an extremely high dislocation density and surface connected initiation yet without a significant life reduction. The observations were essentially similar for the HIP + forged material except that deformation tended to be confined to well defined slip bands even at high strains and to some extent even for the hold time tests. This behavior was attributed to the fact that theγ′ were smaller, more coherent and more readily sheared by dislocations which were strongly paired. There was a marked tendency for crack propagation to change from transgranular to intergranular (also observed for the as-HIP material) at a unique combination of crack length and plastic strain. The transition occurred at shorter crack lengths for the HIP + forged material except when crack initiation was subsurface. In this case the transition was delayed and the life was greatly enhanced, indicating that the environment plays a major role in determining the fatigue life. PHILIPPE TAUPIN formerly Research Associate, Department of Materials Science, University of Cincinnati.     

Rare causes of occult small intestinal bleeding, including aortoenteric fistulas, small bowel tumors, and small bowel ulcers

The most common cause for gastrointestinal bleeding of small bowel origin is angiodysplasia, followed by tumors of the small intestine, and various other causes, including small bowel ulcers and aortienteric fistulas. With the advent of improved diagnostic tests, including push and sonde enteroscopy, timely endoscopic diagnosis of these rare small bowel lesions has become possible, enabling the clinician to make better therapeutic decisions. This article focuses on the rare small bowel sources of intermittent and chronic gastrointestinal blood loss.     

Polyacrylonitrile–poly(1-vinyl pyrrolidone-co-vinyl acetate) blend based gel polymer electrolytes incorporated with sodium iodide salt for dye-sensitized solar cell applications

New gel polymer electrolytes (GPEs) were prepared via the blending of a polyacrylonitrile polymer and a poly(1-vinyl pyrrolidone-co-vinyl acetate) copolymer. The sodium iodide (NaI) salt concentration was varied for each GPE sample. From ionic conductivity (σ) studies, we observed that the sample with a 40 wt % NaI salt content (N40) showed the highest σ of 3.54 × 10⁻³ ± 0.05 S/cm at room temperature, and all of the GPE samples obeyed Arrhenius behavior. The dielectric properties of the GPE samples were also analyzed to study the electrical polarization of the materials. The developed GPE samples were also characterized with X-ray diffraction and Fourier transform infrared spectroscopy. We also then used the developed GPE samples for the fabrication of dye-sensitized solar cells by sandwiching them between a photoanode and Pt counter electrode for photovoltaic studies. The highest photovoltaic performance was achieved by N40, with an efficiency of 3.04%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47810.     

In vitro model improves the prediction of soil arsenic bioavailability: worst-case scenario

There is a strong interest in developing an in vitro arsenic (As) model that satisfactorily estimates the variability in in vivo relative oral bioavailability (RBA) measurements. Several in vitro tests have been developed, but none is universally accepted due to their limited success in predicting soil As RBA. A suite of amorphous and crystalline solid As phases were chosen, utilizing a worst-case scenario (WCS) that simulated fasting children's gastric solution chemistry. The objectives of this study were to (i) determine the effects of residence time, pH, and solid-to-solution ratio on As bioaccessibility and speciation in the in vitro gastric test; (ii) provide the fundamental basis for an optimized in vitro model constrained by the WCS; and (iii) validate the optimized in vitro test with the in vivo RBA obtained with BALB/c mice. The gastric pH was the only significant (p < 0.05) factor influencing solid As bioaccessibility. Bioaccessible As retained the oxidation state after its release from the solid into the gastric solution. The optimized in vitro model adequately predicted RBA values for a suite of solid As phases typically encountered in soils, with the exception of aluminum-based solids. This study is an excellent starting point for developing an in vitro test applicable to different As-contaminated soils.