Homeless youth and their exposure to and involvement in violence while living on the streets

Sick building syndrome is the term given to a heterogeneous constellation of symptoms that affects workers in modern mechanically ventilated office buildings. Although the cause is unknown, there is evidence that the local environment of the work station is an important determinant of symptoms. In this study, investigators examined the effect of a new, individually controlled ventilation system on workers' symptoms. Investigators studied two groups of workers in one mechanically ventilated office building: (1) a control group at whose worksite no intervention was made and (2) an intervention group. The intervention consisted of installation of a device that allowed each worker control over the ventilation supplied to his or her worksite. Just before, and 4 and 16 mo after installation of this device, workers completed self-administered questionnaires regarding occurrence of symptoms. The new ventilation system resulted in higher air velocities, more variable temperatures, and higher concentrations of airborne dust and fungal spores. Four months after installation, workers with the new ventilation system reported fewer symptoms that were (a) work-related (p < .05) and that were work-related and frequent (p < .05); in addition, they reported fewer symptoms that reduced their capacity to work (p < .01). Sixteen months after installation, workers with the new device reported fewer symptoms than at baseline (although not as significantly), and they indicated that the indoor air quality improved their productivity by 11%, compared with a 4% reduction of productivity among the control group of workers (p < .001). Investigators concluded that the new ventilation system, which provided the workers with individual control over ventilation, was associated with important and sustained reduction in symptoms.     

Sites of alcohol and volatile anaesthetic action on GABA(A) and glycine receptors

Volatile anaesthetics have historically been considered to act in a nonspecific manner on the central nervous system. More recent studies, however, have revealed that the receptors for inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine are sensitive to clinically relevant concentrations of inhaled anaesthetics. The function of GABA(A) and glycine receptors is enhanced by a number of anaesthetics and alcohols, whereas activity of the related GABA rho1 receptor is reduced. We have used this difference in pharmacology to investigate the molecular basis for modulation of these receptors by anaesthetics and alcohols. By using chimaeric receptor constructs, we have identified a region of 45 amino-acid residues that is both necessary and sufficient for the enhancement of receptor function. Within this region, two specific amino-acid residues in transmembrane domains 2 and 3 are critical for allosteric modulation of both GABA(A) and glycine receptors by alcohols and two volatile anaesthetics. These observations support the idea that anaesthetics exert a specific effect on these ion-channel proteins, and allow for the future testing of specific hypotheses of the action of anaesthetics.     

Flexible and Conductive 3D Printable Polyvinylidene Fluoride and Poly(N,N‐dimethylacrylamide) Based Gel Polymer Electrolytes

In this work, 3D printable gel polymer electrolytes (GPEs) based on N,N‐dimethylacrylamide (DMAAm) and polyvinylidene fluoride (PVDF) in lithium chloride containing ethylene glycol solution are synthesized and their physicochemical properties are investigated. 3D printing is carried out with a customized stereolithography type 3D gel printer named “Soft and Wet Intelligent Matter‐Easy Realizer” and free forming GPE samples having variable shapes and sizes are obtained. Printed PVDF/PDMAAm‐based GPEs exhibit tunable mechanical properties and favorable thermal stability. Electrochemical proprieties of the printed GPEs are carried out via impedance spectroscopy in the temperature range of 25–90 °C by varying PVDF content. Ionic conductivity as high as 6.5 × 10^?4 S cm^?1 is achieved at room temperature for GPE containing low PVDF content (5 wt%) and conductivity of the GPEs is increased as temperature rises.     

Ta–Rh binary alloys as a potential diffusion barrier between Cu and Si: Stability and failure mechanism of the Ta–Rh amorphous structures

Thermodynamic calculations were carried out to derive the Gibbs free energy diagram for the amorphous and crystalline phases in the Ta–Rh system. These calculations predicted that the compositional range for the amorphous Ta–Rh phase was within 37–66 at.% Ta, which was validated by X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HRTEM) observations and resistivity measurements of as-deposited films. The thermodynamic modeling provided a valuable guide for selecting an amorphous composition suitable for diffusion barrier applications. The stability and metallurgical failure mechanism for TaRh_x diffusion barriers in contact with Cu and/or Si were investigated by resistivity measurements, XRD analysis and detailed electron microscopy on samples annealed in 5% H₂/95% N₂ gas for 30 min at various temperatures. Amorphous TaRh_x in contact with the Si substrate was stable up to 700 °C, whereupon TaRh_x decomposed and reacted to form TaSi₂ and RhSi. Si/amorphousTaRh_x (13 nm)/Cu stacks, on the other hand, were stable only up to 550 °C. Failure occurred by reaction of Rh with the Si substrate to form RhSi at the interface. The large density of defects formed in the barrier layer as a result of outward diffusion of Rh facilitated diffusion of Cu to the Si/TaRh_x interface to form Cu₃Si particles. The formation of Cu₃Si was observed to trigger further silicidation of the barrier to form a discontinuous TaSi₂ layer.     

End-of-life decision-making in the hospital: current practice and future prospects

The contributions of the various ulnar-innervated muscles of the hand to the hypothenar compound muscle action potential (CMAP) were estimated by directly stimulating individual muscles and by analyzing CMAP shape changes resulting from manipulations that changed individual muscle lengths. The results show that the first peak of the negative phase of the hypothenar CMAP comes from the hypothenar muscles, but that the second peak is due to a large volume-conducted potential from the interosseous muscles. The interosseous contribution affects both the amplitude and the area of the CMAP, and makes these parameters sensitive to changes in the configuration of the fingers and the temperature gradient in the hand. To reduce the interosseous contribution, a "balanced reference" consisting of two reference electrodes, one over each tendon, is proposed.     

Pathogenic mechanisms in the rheumatoid nodule: comparison of proinflammatory cytokine production and cell adhesion molecule expression in rheumatoid nodules and synovial membranes from the same patient

OBJECTIVE: To investigate the production of proinflammatory cytokines and expression of cell adhesion molecules in the rheumatoid nodule. METHODS: Cytokine content (tumor necrosis factor alpha [TNFalpha], interleukin-1beta [IL-1beta], and IL-1 receptor antagonist [IL-1Ra]), at the messenger RNA (mRNA) and protein levels, and cell adhesion molecule expression were studied in 16 rheumatoid nodules and 6 synovial membranes. RESULTS: Macrophages in the rheumatoid nodules contained TNFalpha, IL-1beta, and IL-1Ra mRNA and protein, particularly in perivascular cells of the stroma and in the palisading layer. All cell adhesion molecules studied were expressed in both the rheumatoid nodules and synovial membranes, with increased expression of E-selectin in the rheumatoid nodule compared with the synovial membrane, and with the absence of vascular cell adhesion molecule 1 expression on cells of the palisading layer in the rheumatoid nodule. CONCLUSION: The presence of similar proinflammatory cytokines and cell adhesion molecules in the rheumatoid nodule and synovial membrane suggests that similar pathogenic processes result in the chronic inflammation and tissue destruction in these lesions.