Ultraviolet absorption spectra: Some substituted coumarins

The u.v. absorption spectra of forty-one substituted coumarins have been studied in methanol and aqueous methanol over a pH range. The effect of the nature and position of the substituent in the coumarin nucleus is discussed.     

A CMOS RF front-end for a multistandard WLAN receiver

This letter describes the design and performance of a dual band tri-mode receiver front-end compliant with the IEEE 802.11a, b, and g standards. The receiver front-end was built in a 0.18-/spl mu/m CMOS process and achieves a noise figure of 4.7 dB/5.1 dB for the 2.4-GHz/5-GHz bands, respectively. The receiver front-end provides a dual gain mode of 5 dB/30 dB with an IIP3 of -1dBm for the low gain mode. The front-end draws 25 mA/27 mA from a 1.8-V supply for the 2.4-GHz/5-GHz bands, respectively.     

Strength differential in Al---Li alloy 8090

Cyclic strength differential (SD) data have been derived from the variation of the tensile and the compressive stress amplitude with elapsed cycles during low cycle fatigue (LCF) for the quaternary Al---Li alloy 8090 in the T8E51 condition. LCF test specimens were machined out of the rolled plate such that the direction of stressing was along the longitudinal (L), L+45° and long transverse (LT) directions. The analysis of cyclic stress amplitude data corresponding to the half-life revealed an SD effect at all strain levels in the L+45° and LT directions. In the case of the L direction, at strain levels below 8.5 × 10⁻³, the SD is more than compensated by the Bauschinger effect resulting from the prestretch. The alloy exhibits a similar SD behaviour under monotonic loading conditions. The magnitude of cyclic SD at intermediate strain amplitudes in all the three test directions decreases upon cycling, which behaviour can be attributed to the relaxation of prestretch-related residual stresses leading to a decrease in σ_T only in the L direction and σ_C only in the L+45° and LT directions. As microstructural features vary in the differently heat-treated conditions, a comparison has been made of the monotonic SD data in the stretched and aged (T8E51) condition with those in the solution-treated, in the peak-aged (T6) and in the overaged (T7) conditions.     

Implementation of the national cervical cancer screening in general practice and feasibility of a general practice-based call system: the GP''s opinion

A male fetus is described with multiple congenital abnormalities including craniosynostosis and bilateral radial aplasia. There are many similarities to the case recently reported by Imaizumi and Kuroki (Am J Med Genet 41: 162-163). These cases may represent a new syndrome with overlapping features of the Baller-Gerold and Roberts syndromes.     

Laryngeal reinnervation: transposition of neuromuscular pedicles

Following Tucker's technique, a muscle-nerve pedicle implantation in the denervated posterior cricoarytenoid muscle was performed in five dogs. Results were evaluated after six months by videolaryngoscopy, evoked muscle action potentials and histomorphometric studies. Partial motion recovery of the reinnervated side was observed endoscopically in three dogs. Histomorphometric evaluation showed evidence of muscle reinnervation in all of the five dogs. However, no muscle action potentials were obtained in the posterior cricoarytenoid muscles after stimulation of the ansa hypoglossi branch. These data suggest that the ansa hypoglossi neuromuscular pedicle does not result in reinnervation, and that reinnervation of the posterior cricoarytenoid muscle may occur via other neuromuscular pathways.     

Association of the antibody response to hemocyanin with behavior in mice bred for or low antibody responsiveness.

Researchers attempted to find a genetic correlation between the antibody response and some behaviors by comparing the behavioral profile of good antibody-producing mice (Biozzi's H mice) with that of bad antibody producers (Biozzi's L mice). The behavioral tests used were 2 open fields, a light–darkness test, and reaction to capture; the antigen was keyhole limpet hemocyanin, and blood levels of immunoglobulin (Classes IgM and IgG) antibodies to hemocyanin were measured by diffusion-in-gel-enzyme-linked immunosorbent assay. H and L mice differed in the magnitude of the antibody response (H?>?L), in reaction to capture (L?>?H), and in rearing in 1 of the open fields (L?>?H). Yet the level of IgM or IgG antibodies was uncorrelated with those behaviors in the (H?×?L) F, hybrids and in outbred CDI mice. Thus, the behavioral differences between H and L mice are not due to the antibody response genes but to other genes fixed during selection for antibody responsiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Platon: a university local area network

Platon is a local area network set up in the Department of Electrical Engineering, University of Ottawa, operating at 1 Mbit/s and interconnecting departmental computers, terminals, peripherals, various instruments and the university mainframe. The primary objective of Platon is to facilitate network evolution and provide resource sharing by supporting various application protocols such as database access and file transfer. In addition, Platon is intended to serve as a research vehicle for distributed systems studies. To this end, a packet-voice system and a packet-radio gateway are concurrently being developed. Platon has adopted the bus architecture, using a coaxial cable with CSMA/CD as its access protocol. Retransmissions of collided packets are scheduled using a linear incremental backoff (LIB) algorithm.     

Heat transfer characteristics of a two dimensional laminar wall jet with non-isothermal surface conditions

An analysis is presented to investigate the steady state heat transfer characteristics of a laminar, incompressible, two dimensional wall jet with a step discontinuity in surface temperature. The non-similar thermal boundary layer problem is solved by a series solution method. Analytical expressions are obtained for the temperature field and the surface heat flux with Prandtl number as a parameter.     

Transient response behavior of an axisymmetric stagnation flow on a circular cylinder due to time dependent free stream velocity

An analysis is presented to investigate the unsteady response behavior of an axisymmetric stagnation flow on a circular cylinder due to transient free stream velocity. The governing boundary layer equations are integrated by the steepest descent method. Numerical results have been presented for the unsteady wall stress by assuming explicit time dependent forms for the free stream velocity.