Extensive restriction site polymorphism at the human phenylalanine hydroxylase locus and application in prenatal diagnosis of phenylketonuria

A total of 10 restriction site polymorphisms have been identified at the human phenylalanine hydroxylase locus using a full-length human phenylalanine hydroxylase cDNA clone as a hybridization probe to analyze human genomic DNA. These polymorphic patterns segregate in a Mendelian fashion and concordantly with the disease state in various PKU kindreds. The frequencies of the restriction site polymorphisms at the human phenylalanine hydroxylase locus among Caucasians are such that the observed heterozygosity in the population is 87.5%. Thus, most families with a history of classical phenylketonuria can take advantage of the genetic analysis for prenatal diagnosis and carrier detection of the hereditary disorder.     

The effect of an infusion of low molecular weight dextran on peripheral resistance in patients with arteriosclerosis

Low molecular weight dextran is frequently given to improve the flow of blood to the periphery, but its mode of action is uncertain. We measured the effect of an infusion of 500 ml of Dextran 40 on the peripheral resistance in 12 patients undergoing reconstructive surgery for atherosclerotic occlusion of the superficial femoral artery. After the infusion, values of packed cell volume and blood viscosity indicated haemodilution. There was a consistent increase in mean flow and a fall in peripheral resistance. There was no correlation between change in viscosity and change in peripheral resistance, but there was a good correlation between the percentage change in resistance and the initial resistance. This suggests that the increase in flow of blood was due to reflex vasodilatation rather than to any reduction in viscosity.     

Measurement of neutron fluence spectra up to 150 MeV using a stacked scintillator neutron spectrometer

A stacked scintillator neutron spectrometer (S3N) consisting of three slabs of liquid organic scintillator is described. A pulsed beam providing a broad spectrum of neutron energies is used to determine the detection efficiency of the spectrometer as a function of incident neutron energy and to measure the pulse height response matrix of the system. Neutron spectra can then be determined for beams with any kind of time structure by unfolding pulse height spectra measured by the S3N. Examples of fluence spectrum measurements in the energy range 20-150 MeV are presented.     

A Compact Model for Valence-Band Electron Tunneling Current in Partially Depleted SOI MOSFETs

The valence-band electron (EVB) tunneling current in partially depleted silicon-on-insulator (SOI) MOSFETs increases as the gate oxide gets thinner and affects the dynamic behavior of devices and circuits. We present an engineering model of EVB tunneling current based on the surface-potential formulation. The new model is implemented in a SOI MOSFET compact model and is used to study the impact of EVB tunneling on circuit performance. Simulations of stacked logic gates show that the EVB tunneling current not only boosts circuit switching speed but also mitigates the history dependence of propagation delays     

Self-switching in Mach-Zehnder interferometers with SOA phase shifters

A self-switching mechanism in Mach-Zehnder interferometers (MZIs) is described. The input light signal is distributed unequally over the interferometer arms using an multimode interference (MMI) coupler. In the arms, semiconductor optical amplifiers are placed as nonlinear phase shifters. Unequal intensities yield a nonlinear phase shift. The signals from the two arms are then recombined in an output MMI coupler. If an obtained nonlinear phase shift in the arms can compensate the coupler-induced phase difference between the arms, the signals are in phase at the output port. Choosing an appropriate output coupler, 2/spl times/1 and 2/spl times/2 devices can be obtained. The 2/spl times/2 and 2/spl times/1 MZIs can be used as pattern effect compensators and 2R-regenerators or low-loss combiner circuits, respectively. An active-passive integration technique is applied in order to realize the interferometric structures. Fabrication, simulation, and characterization of these devices are presented in this letter.     

An in vitro tissue culture bilayer model to examine early events in Mycobacterium tuberculosis infection

A tissue culture bilayer system that mimics some aspects of early alveolar infection by Mycobacterium tuberculosis was developed. This model incorporates human lung epithelial type II pneumocyte (A549) (upper chamber) and endothelial cell (lower chamber) layers separated by a microporous membrane. This construction makes it possible to observe and quantify the passage of bacteria through the two layers, to observe the interaction of the bacteria with the various cell types, and to examine the basic mechanisms of immune cell recruitment to the site of infection. After 10(7) organisms were added to the upper chamber we microscopically observed large numbers of bacteria attached to and within the pneumocytes and we determined by viable-cell counting that a small percentage of the inoculum (0.02 to 0.43%) passed through the bilayer into the lower chamber. When peripheral blood mononuclear cells were added to the lower chamber, microscopic examination indicated a migration of the mononuclear cells through the bilayer to the apical surface, where they were seen associated with the mycobacteria on the pneumocytes. The added complexity of the bilayer system offers an opportunity to define more precisely the roles of the various lung cell types in the pathogenesis of early tuberculosis.     

Study of electrocatalysts for oxygen reduction based on electroconducting polymer and nickel

The properties and electrocatalytic activity were studied of composite carbon‐supported materials based on heterocyclic polymer and nickel, in particular carbon/polyaniline/nickel, carbon/polypyrrole/nickel, carbon/poly(3‐methylthiophene)/nickel, as well as their precursors, carbon/polyaniline, carbon/polypyrrole, and carbon/poly(3‐methylthiophene). The materials were characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDAX, and electrochemical methods, such as cyclic voltammetry and linear voltammetry using RDE. SEM show porous materials, with a particle size of around 0.3 μm. It was found that in nickel‐modified catalysts between 5 and 6 wt % of nickel is obtained. TGA and FTIR show that the modification with nickel alters the polymer bonds. Curves from cyclic voltammetry show cathodic peaks corresponding to the oxygen reduction reaction (ORR) in all materials, occurring at relatively low potentials. Based on the potential range for ORR as well as kinetic parameters obtained from linear voltammetry using RDE, it was concluded that C‐Ppy‐Ni shows the best performance for ORR in acidic medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Randomized trial of internet-delivered self-help with telephone support for pathological gamblers.

Although effective therapies for pathological gambling exist, their uptake is limited to 10% of the target population. To lower the barriers for help seeking, the authors tested an online alternative in a randomized trial (N = 66). The participants were pathological gamblers not presenting with severe comorbid depression. A wait-list control was compared with an 8-week Internet-based cognitive behavior therapy program with minimal therapist contact via e-mail and weekly telephone calls of less than 15 min. Average time spent on each participant, including phone conversations, e-mail, and administration, was 4 hr. The Internet-based intervention resulted in favorable changes in pathological gambling, anxiety, depression, and quality of life. Composite between-group effect size (Cohen's d) at posttreatment was 0.83. Follow-ups carried out in the treatment group at 6, 18, and 36 months indicated that treatment effects were sustained (ds = 2.58, 1.96, and 1.98). This evidence is in support of Internet-delivered treatment for pathological gamblers. However, it is not clear how effective the treatment is for more severely depressed individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prism-coupling of light into narrow planar optical waveguides

The efficiency and selectivity of the prism-coupler for exciting single modes in narrow planar optical waveguides is investigated both theoretically and experimentally. A previously published calculation of the coupling efficiency between a plane input wave with finite cross section and a number of waveguide modes, as a function of both the incidence angle and the skew angle, is extended to include the effects of diffraction, which are shown to play a dominant role for small focal widths of the input beam. The theoretical predictions are compared with experimental results obtained at 633 nm on an embedded ridge-type waveguide structure. A number of mechanisms reducing coupling selectivity and stability are discussed, and some practical rules are given for obtaining good stability and selectivity