Antioxidant defenses influence HIV-1 replication and associated cytopathic effects

HIV-infected cells often exhibit reduced levels of antioxidant enzymes and thiols. To investigate the role of cellular antioxidant defenses in the progression of an acutely spreading HIV-1 infection, human Sup-T1 T cells were engineered to overexpress the selenium-dependent glutathione peroxidase, GSHPx-1. This enzyme represents a major cellular defense mechanism against toxicity associated with reactive oxygen species (ROS). T cells engineered to produce elevated GSHPx-1 activity displayed accelerated viral replication and associated cytopathic effects compared to control cells. Conversely, the inhibition of the synthesis of glutathione with buthione sulfoximine (BSO) resulted in the attenuation of viral replication in Sup-T1 cells. Similarly, exposure of human peripheral blood lymphocytes (PBLs) to low, nontoxic levels of BSO resulted in an approximately 80% decline in HIV-1 replication as indicated by Western blot analysis of viral proteins.     

Asymmetric waveguide devices with buried AlO/sub x/ cladding layers

We demonstrate a highly asymmetric waveguide filter for wavelength division multiplexing applications using wet oxidation of AlAs to form low-index cladding layers. The dual waveguide structure consists of a low-index polymer waveguide coupled to a lossy high-index AlGaAs waveguide. The high asymmetry between the polymer and AlGaAs yields high resolution at small device lengths. The light is coupled in and out of the polymer guide and exhibits Fabry-Perot-like resonances as the light couples to different modes of the AlGaAs. With a device length of 400 /spl mu/m, we observe resonances with a width of about 1 nm at 800 nm, agreeing with theoretical expectations. In addition to the simple filter demonstrated here, such a structure could be used to form active light emitting or detector devices.     

Decline in the prevalence of HIV-1 infection in young women in the Kagera region of Tanzania

Illness representations were assessed in 63 adults with rheumatoid arthritis (RA) and 66 with multiple sclerosis (MS). The relationship of illness representations to concurrent and later mood was explored. MS patients' beliefs in symptom variability were associated with higher depressed mood 4 months later, over and above initial levels of depression. RA patients who saw RA as curable or who saw themselves as responsible for the illness reported significant increases in depression over time. Belief in the serious consequences of RA interacted with later illness severity to predict change in depression. When belief in the serious consequences of RA was high, less severe illness status was associated with less depression and more severe illness status was associated with more depression. When RA was initially viewed as only moderately serious, less severe illness was associated with somewhat higher levels of depression.     

Performance of diffractive optical elements for homogenizing partially coherent light

The effectiveness of different types of diffractive optical element (DOE) for homogenizing partially coherent beams is analyzed, both analytically and numerically. The effectiveness is described by the homogenizing parameter, defined as the inverse of the normalized variance of the dose distribution. For an important class of DOEs designed with common discrete-Fourier-transform methods, it is found that the homogenizing parameter is only of the order of the number of coherence cells in the illuminating beam. However, for a different type of DOE that produces distinct beams under coherent illumination, the homogenizing parameter can be an order of magnitude higher. The inherent dehomogenizing effect caused by the limited temporal duration of the beam, a phenomenon sometimes referred to as dynamic speckle, is also considered.     

MODELING THE PHYSICS OF METAL CUTTING IN HIGH-SPEED MACHINING

ABSTRACT

Physical modeling of metal cutting was carried out to provide an understanding and prediction of machining process details. The models are based on finite element analysis (FEA), using a Lagrangian formulation with explicit dynamics. Requirements for material constitutive models are discussed in the context of high-speed machining. Model results address metal cutting characteristics such as segmented chip formation, dynamic cutting forces, unconstrained plastic flow of material during chip formation, and thermomechanical environments of the work-piece and the cutting tool. Examples are presented for aerospace aluminum and titanium alloys. The results are suited for analysis of key process issues of cutting tool performance, including tool geometry, tool sharpness, workpiece material buildup, and tool wear.     

Discharge destination and motor function outcome in severe stroke as measured by the functional independence measure/function-related group classification system

OBJECTIVES: Function-related groups based on the Functional Independence Measure have been proposed as a model for a prospective payment system for medical rehabilitation. This study describes discharge destination and motor function outcomes in a sample of patients with stroke from the FIM-FRG STR1 classification. STUDY DESIGN: A retrospective review of 293 cases of stroke from the years 1993 to 1995. The demographic and outcome characteristics of this sample were described. RESULTS/CONCLUSIONS: Forty-five percent of the patients were discharged to home after a mean length of stay of 23.8 days in acute medical rehabilitation. Patients who were discharged home had higher admission and discharge motor FIM scores than those discharged to a subacute facility or long-term care facility, although the correlation between motor FIM score and discharge destination was low to moderate. Median discharge motor FIM scores indicate considerable residual disability in this classification after rehabilitation. Research problems that address methods to improve the usefulness of the FIM-FRG system in a prospective payment system are discussed.     

Reactivation treatment prevents the memory-impairing effects of scopolamine in preweanling rats.

The authors report that the expression of a conditioned odor aversion is impaired in preweanling rats when they are conditioned on Postnatal Day 12 and tested under the influence of scopolamine hydrobromide (0.2 or 0.5 mg/kg, intraperitoneal) after a 48-hr, but not after a 2-hr, retention interval (Experiment 1). This effect of scopolamine is not dependent on maturation of the cholinergic system between Days 12 and 14 (Experiment 2), nor is it due to peripheral mechanisms (Experiment 3). When pups are reexposed to the unconditioned stimulus (footshock) before drug administration, performance on the 48-hr retention test is not impaired by scopolamine (Experiment 4). These findings demonstrate that the cholinergic system may be critical for the retrieval and expression of long-term or weak memories in young rats. However, the expression of active memories (recent or recently reactivated) may not be dependent on the cholinergic system to the same extent as is the expression of inactive memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shape memory materials and hybrid composites for smart systems: Part II Shape-memory hybrid composites

By hybridizing or incorporating shape-memory materials with other functional materials or structural materials, smart composites can be fabricated which may utilize the unique functions or properties of the individual bulk materials to achieve multiple responses and optimal properties, or, to tune their properties to adapt to environmental changes. A variety of shape-memory hybrid composites have been designed and manufactured, with shape-memory elements being either the matrix or the reinforcement. The hybrid composites provide tremendous potential for creating new paradigms for material–structural interactions and demonstrate varying success in many engineering applications. This review, from the standpoint of materials science, will give a state-of-the-art survey on the various shape-memory hybrid smart composites developed during the last decade. Emphasis is placed on the design, fabrication, characterization and performance of fibre-reinforced, particle-reinforced and multi-layered thin-film shape-memory composites.     

ABL and BAM Friction Analysis Comparison

The Integrated Data Collection Analysis (IDCA) program has conducted a proficiency study for Small‐Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here is a comparison of the Alleghany Ballistic Laboratory (ABL) friction data and Bundesanstalt für Materialforschung und ‐prüfung (BAM) friction data for 19 HME and military standard explosives. Two methods were employed to reduce the data – modified Bruceton analysis (F₅₀) and the threshold initiation level analysis (TIL). The study provides a full list of friction sensitivity data for the 19 materials by both ABL and BAM friction testing equipment. Specific results highlight the differences more than the similarities of the two methods. PETN and KClO₃/sugar mixtures exhibit the most sensitivity of the materials studied by both testing methods. On the other hand, H₂O₂/fuel mixtures exhibit no sensitivity in ABL testing, but exhibit some sensitivity in BAM testing. For the UNi mixtures, the behavior was the opposite, no sensitivity in BAM but some sensitivity in ABL. KClO₄/Al mixtures exhibit high sensitivity in the ABL method, but only moderate sensitivity in the BAM method. Other differences are seen in the relative sensitivities underscoring the differences in the mechanisms of how each test method operates. In some cases, data could not be attained because of the physical nature of the material. Comparison between the two friction methods on a material‐by‐material basis using absolute values not surprisingly yielded essentially no systematic correlations. Even the relative order showed little correlation between the two methods. The Department of Homeland Security (DHS) funded this effort. Each participating testing laboratory uses identical test materials and preparation methods. However, the test procedures differ among the laboratories. The testing performers involved are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Naval Surface Warfare Center, Indian Head Division Explosive Ordnance Disposal Technology (NSWC IHEODTD), Sandia National Laboratories (SNL), and Air Force Research Laboratory (AFRL/RXQL).