Recent Surge in Homicides Involving Young Black Males and Guns: Time To Reinvest in Prevention and Crime Control

This review of recent U.S. homicide trends by race of offenders and victims, as well as weapons used, shows a surge in homicides that involve young Black males and guns

Hot corrosion of ceramic engine materials

A number of commercially available SiC and Si3N4 materials were exposed to 1000 C in a high velocity, pressurized burner rig as a simulation of a turbine engine environment. Sodium impurities added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si4N4 and formation of substantial Na2O-x(SiO2) corrosion product. Room temperature strength of the materials decreased. This was a result of the formation of corrosion pits in SiC, and grain boundary dissolution and pitting in Si3N4. Corrosion regimes for such Si-based ceramics have been predicted using thermodynamics and verified in rig tests of SiO2 coupons. Protective mullite coatings are being investigated as a solution to the corrosion problem for SiC and Si3N4. Limited corrosion occurred to cordierite (Mg2Al4Si5O18) but some cracking of the substrate occurred

Molten salt corrosion of SiC and Si3N4

Industrial systems such as heat engines and heat exchangers involve harsh environments. The structural materials are subjected to high temperatures as well as corrosive gases and condensed phases. Past experience with metal alloys has shown that these condensed phases can be particularly corrosive and are often the limiting factor in the operation of these systems. In a heat engine the most common condensed corrodent is Na2SO4 whereas in a heat exchanger an oxide slag may be present. The primary emphasis is on Na2SO4 induced corrosion, however, similarities and differences to oxide slag are also discussed. The extensive research on corrosion of metal alloys has led to understanding and controlling corrosion for these materials. Currently silicon based ceramics are prime candidates for the applications discussed. Therefore it is important to understand the effects of condensed phase deposits on this emerging class of high temperature materials. Both the thermodynamic and strength of the ceramic is also examined. Finally some control strategies for corrosion of silicon based ceramics are explored

Symptoms of Plant Malnutrition--Silicon, an Agronomically Essential Nutrient for Sugarcane

Deficiences of silicon in a Si-deficient soil (a Gibbsihumox) causing a "leaf freckle" disorder are illustrated with photos of sugarcane leaves from plants grown with or without an application of calcium silicate slag. Effects of diminished leaf growth caused by silicon deficiency on presence of weeds under the canopy are also shown

Methamphetamine and Inflammatory Cytokines Increase Neuronal Na+/K+-ATPase Isoform 3: Relevance for HIV Associated Neurocognitive Disorders

Methamphetamine (METH) abuse in conjunction with human immunodeficiency virus (HIV) exacerbates neuropathogenesis and accelerates neurocognitive impairments in the central nervous system (CNS), collectively termed HIV Associated Neurocognitive Disorders (HAND). Since both HIV and METH have been implicated in altering the synaptic architecture, this study focused on investigating alterations in synaptic proteins. Employing a quantitative proteomics approach on synaptosomes isolated from the caudate nucleus from two groups of rhesus monkeys chronically infected with simian immunodeficiency virus (SIV) differing by one regimen, METH treatment, we identified the neuron specific Na+/K+-ATPase alpha 1 isoform 3 (ATP1A3) to be up regulated after METH treatment, and validated its up regulation by METH in vitro. Further studies on signaling mechanisms revealed that the activation of ATP1A3 involves the extracellular regulated kinase (ERK) pathway. Given its function in maintaining ionic gradients and emerging role as a signaling molecule, changes in ATP1A3 yields insights into the mechanisms associated with HAND and interactions with drugs of abuse

Surface analysis of environmentally exposed painted composites manufactured from Quickstep and autoclave processes

The surface finishes of laminates produced by Quickstep&trade; and autoclave processes for use in automotive outer skin panels were compared. Automotive quality, painted carbon fibre samples, manufactured via both processes, were exposed to typical exposure environments including combinations of temperature (70, 120, 170&deg;C), UV-B, humidity (95% RH) and immersion in water.The microscopy and surface roughness results demonstrated that the surfaces produced by the Quickstep process were less susceptible to damage in the aging environments than the surfaces of the autoclaved samples. Quickstep samples displayed surface bubbling of only 5 &mu;m, compared to the autoclaved surface bubbles which reached a diameter of 30 mm before bursting, with complete delamination occurring between the paint and the composite. The surface roughness measurements revealed the autoclave samples (Ra = 0.72 &mu;m) were up to three times the roughness of the Quickstep samples (Ra = 0.23 &mu;m).<br /

Microfiltration in oceanographic research II. Retention of colloidal micelles by adsorptive filters and by filter-feeding invertebrates; proportions of dispersed organic to dispersed inorganic matter and to organic solutes

To adsorb and retain quantitatively the minute colloidal micelles held in dilute suspensions, fine inert inorganic powders (such as MgO and refined diatomaceous earth) or finely porous cellulose membranes may be employed. Minute micelles, such as molecular hemoglobin, are retained also by setous or ciliary-mucous filterfeeders...