Buffy coat platelets stored in apyrase, aprotinin, and ascorbic acid in a suspended bag: combined strategies for reducing platelet activation during storage

The aim of the study was to compare the masticatory pattern and the activity of the masticatory muscles of a group of myotonic dystrophy patients with those of a group of healthy individuals. The electromyographic (EMG) activity of the temporal and the masseter muscles was measured in the resting position, during maximal clenching, and while the patient was chewing five peanuts until swallowing. It was found that the patients had approximately 3 times less EMG activity in the masticatory muscles during maximal clenching. During chewing the patients had approximately half the activity in the anterior temporal and the masseter muscles, while the activity of the posterior temporal muscle did not differ significantly from that in healthy individuals. No differences were found in the muscle activity in the resting position or in the speed of chewing between the groups. The patients needed more time and more chewing cycles to bring the five peanuts to the swallowing threshold, but possibly this was an effect of the lower number of antagonizing teeth. Myotonic dystrophy thus influences the masticatory muscles, reducing their activity both at a maximal and a functional level.     

Effect of seleno-organic compounds on leukotriene B4 biosynthesis

Leukotrienes (LTs) are a group of metabolites of arachidonic acid through the 5-lipoxygenase pathway. Among these metabolites, LTB4 is an important mediator of inflammatory disease. Recently, it has been shown that seleno-organic compounds are very biologically active. One of them, Ebselen [2-phenyl-1,2-benzoisoselenazol-3 (2H) one] is a new seleno-organic compound with very low toxicity while exhibits anti-inflammatory activity. Attempt to search for seleno-organic compounds as anti-inflammatory drugs and establish structure-activity relationships, ten ebselen derivatives with modifications in the 2-phenyl moiety were studied with respect to their effects on LTB4 biosynthesis. p-substituted compounds were shown to have stronger inhibitory activity on LTB4 biosynthesis than o-substituted compounds and ebselen itself. Among the p-substituted compounds, polar-inducing group-substituted compounds showed stronger activity than compounds substituted with polar-conjugated groups. Among the compounds substituted with polar-inducing groups, strongpolar groups exhibited stronger activity than weakpolar groups.     

On the nature of the martensitic transformation

A novel conceptual approach to martensitic transformation is presented. The current concepts are discussed briefly, and a more general qualitative approach to this type of phase change is proposed. It is suggested that the transformation originates in lattice vibration modes, and that once initiated it proceeds adiabatically with no discernible division into nucleation and growth. The transformation does not occur through a dislocation mechanism, and the high dislocation densities observed as associated with martensite formation consist of immobile dislocations. These form to accommodate the transformation strains which are highly localized, but are also self-accommodating and on completion of the transformation are macroscopically nondirectional. All of the anomalies in the mechanical properties reported in the past are ascribed to the effects of an applied stress on the transformation. It is suggested that investigations of such effects on transformation, particularly in single crystal material, should be most fruitful in providing new fundamental insight into the mechanism of the transformation.     

Multicolor voltage-tunable quantum-well infrared photodetector

A novel concept for a quantum-well infrared photodetector (QWIP) with a spectral response peak tunable by an external voltage is described and tested experimentally. This multicolor detector structure is made by stacking conventional (one-color) QWIPs, separated by thin, heavily doped layers (≈90 nm in the test structure). The most important feature is that externally applied DC voltage is distributed among the different one-color QWIPs according to their DC resistances. Each one-color QWIP therefore turns on sequentially in the order determined by its resistance     

Fatty acid composition of breast adipose tissue in breast cancer patients and in patients with benign breast disease

In this study, we report on the cell adhesion properties of marrow stromal cells to extracellular matrix components such as collagen and noncollagenous proteins. The osteoblastic cells and their non-osteoblastic counter-parts (MBA series) from the marrow stroma differentially recognized a spectrum of extracellular matrix proteins. The osteoblastic cells, MBA-15, preferentially attached to bone matrix proteins, whereas fibroendothelial MBA-2.1 and adipocytic 14F1.1 cells did not. The MBA-15 cells demonstrated a preference in their attachment to fibronectin > mixture of collagens > bone matrix extracts > collagen type I > noncollagenous proteins. Clonal subpopulations derived from the MBA-15 cell line representing various stages along the osteogenic lineage expressed differential attachment preference. MBA-15.4, a less differentiated clonal line, was compared to MBA-15.6, a mature cell line.     

Intracavity Beam Behavior in Hybrid Resonator Planar-Waveguide CO(2) Lasers

We describe a combined computer simulation and experimental investigation of the intracavity spatial beam profile characteristics of a planar-waveguide rf-excited CO(2) laser that incorporates a hybrid waveguide confocal unstable negative-branch resonator. The study includes results for the intracavity lateral beam intensity profile and output power of the laser as a function of resonator mirror misalignment. In addition, the behavior of the unstable resonator, observed experimentally and predicted by the simulation, in generating localized high intensity hot-spots when it is subjected to relatively large misalignment angles is reported.     

Solid-State AC Drives: New Reliability for Packaging Equipment

Today's low cost variable frequency inverter drives combined with standard three-phase ac motors, eliminate downtime and maintenance of mechanical speed changers, dc motor armatures, and brushes. Advances in power semi-conductor technology makes the ac drive cost competitive with traditional variable speed drives.