High Performance CMOS Analog Arithmetic Circuits

Unique designs for CMOS analog arithmetic circuits are presented which perform addition (V₁ + V₂), subtraction (V₂ – V₁), add/invert –(V₁ + V₂), and multiply (V₁ × V₂). The circuit operation is based on the inherent square law of MOS transistor drain current when operating in the saturation region. Key features include: good linearity and accuracy, single ended voltage inputs and output, wide input and output range and no input bias voltages. The circuits can be directly coupled (no buffer) and serve as basic building blocks for analog signal processing implementations such as analog filters and adaptive equalizers. All circuits were implemented in 1.2 m CMOS technology.     

Determination of K Id at or below NDTT using instrumented drop-weight testing

Two kinds of surface cracked specimens are numerically analyzed by the three dimensional elastic-plastic FEM. Near tip regions are divided into fine elements, and the stress and displacement fields at the crack tip are compared with HRR solutions.At first, surface cracked specimens subjected to bending are analyzed by changing the aspect ratio and depth/thickness ratio. The effect of the loading condition, crack shape and the crack depth on the stress and displacement fields are discussed. Then the pipe with surface crack subjected to bending is analyzed and the availability of the J-integral concept to the LBB analysis is discussed.In every specimen, it is shown that in the regions very near to the crack tip, the displacement field is similar to HRR solutions of plane strain. In the outer regions, however, the stress and displacement fields depend strongly on the shape, thickness, and loading conditions.     

Grain size estimation in anisotropic materials

The need for an efficient sampling technique for estimation of grain size in anisotropic materials is addressed through statistical analysis of quantitative metallographic data on a series of iron specimens cold rolled to different extents. The data are utilized to arrive at the most efficient procedure for measuring grain size in anisotropic materials. The analysis reveals that, for cold-rolled materials, design-based intersection counting on a single longitudinal metallographic plane is sufficient to reliably and efficiently estimate the average grain size.     

Specific binding of L-triiodothyronine modulates Na(+)-K(+)-ATPase activity in adult rat cerebrocortical synaptosomes

Interactions of L-triiodothyronine (T3) in adult rat cerebrocortical synaptosomes were studied in vitro. Scatchard plot analysis revealed two sets of T3 binding sites. The degree of saturation of T3 binding sites (putative receptor) correlated well with the dose-dependent inhibition of Na(+)-K(+)-ATPase activity in synaptosomes. The relative binding affinities and relative inhibition of enzyme activities for different TH analogues were L-T3 > T3-amine > TRIAC = L-T4 > r-T3 > T2 and L-T3 > T3-amine > TRIAC > L-T4 > r-T3 > T2, respectively. The present study demonstrates the nature of inhibition of synaptosomal Na(+)-K(+)-ATPase activity may be as a function of T3 occupancy of synaptosomal receptor sites in adult mammalian brain.     

Increased incidence of congenital malformations in children with transient thyroid-stimulating hormone elevation on neonatal screening

Huntington's disease is an autosomal-dominant inherited progressive neurodegenerative disease associated with an expanded trinucleotide repeat (CAG) sequence on the short arm of chromosome 4. The disease is considered rare in Africans. We report five black South African families of different ethnic origin with proven expansions typical of Huntington's disease and discuss the possible origins of the disease in Africa.     

X.25 protocols in the airline industry

The requirements of a highly reliable data transport mechanism are outlined, and a practical implementation of the CCITT/ISO standards within the airline is demonstrated. An understanding of the ISO Open Systems Interconnection architecture, as well as CCITT recommendations such as X.25 and X.75, is assumed. The selection of various X.25 subsets and how they meet the data communications needs of a variety of interconnection structures are then described. Finally, the paper reviews the current work being undertaken with respect to the higher layers of the ISO OSI architecture.     

Twin similarity in cardiovascular stress response.

Measured blood pressure and heart rate in 12 pairs of identical and 21 pairs of fraternal male twins (aged 54–64 yrs) during a mental arithmetic task and during submersion of the S's left hand in 4°C water for 60 sec. The results suggest that certain measures of cardiovascular reactivity to laboratory stressors may be heritable for both physical and psychological stressors. The possible role of this genetic component in the etiology and course of coronary heart disease is discussed. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intracerebral haemorrhage in a young adult: consider amphetamine abuse

We present the case of a young female who suffered a massive intracerebral bleed following the ingestion of a small quantity of amphetamine (speed). Physicians should be aware that amphetamine abuse can lead to cerebrovascular events in young adults.