On the effect of artificial-viscosity methods in calculating shocks

Summary Two representative difference-methods of first and second order accuracy are investigated as to their effect in computing shocks. It is shown that the effect of diffusing the shocks is caused entirely by the truncation-error. This opens the possibility of influencing the computed shock-thickness by suitably choosing the parameters in the difference-equations.     

A new rigid gas-permeable semi-scleral contact lens for treatment of corneal surface disorders.

Some extreme corneal irregularities cannot be treated adequately with corneal contact lenses. For such cases a rigid semi-scleral lens can be prescribed. We evaluated the use of a highly gas permeable rigid semi scleral lens in patients with diseased corneas for whom conventional contact lens strategies had failed. Twenty two patients (29 eyes) were successfully fitted with individually manufactured semiscleral lenses. Corneal hypoxia, which has previously limited the use of polymethylmethacrylate (PMMA) scleral contact lenses, did not occur. The semi scleral lenses were well tolerated. Two cases were selected to illustrate the fitting of these lenses.     

Effects of Perinatal Exposure to PCBs on Neuropsychological Functions in the Rotterdam Cohort at 9 Years of Age.

PCBs are known for their neurotoxic properties, especially on the developing brain. To increase insight into the neurotoxic effects of PCB exposure, the authors studied the effects of perinatal exposure to environmental levels of these compounds on different neuropsychological domains. In 9-year-old children of the Rotterdam PCB--dioxin cohort, higher prenatal PCB levels were associated with longer response times (RTs), more variation in RTs, and lower scores on the Tower of London (TOL; Shallice, 1982). A longer breast-feeding duration was associated with lower TOL scores and with better spatial organizational skills. There was some evidence of negative effects of lactational exposure to PCBs on scores on the TOL. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular cloning and characterization of an invertebrate homologue of a neuropeptide Y receptor

Neuropeptide Y is an abundant and physiologically important peptide in vertebrates having effects on food intake, sexual behaviour, blood pressure and circadian rhythms. Neuropeptide Y homologues have been found in invertebrates, where they are very likely to play similar, important roles. Although five neuropeptide Y-receptor subtypes have been identified in mammals, none has been reported from invertebrates. Here we describe the cloning of a neuropeptide Y-receptor from the brain of the snail Lymnaea stagnalis. The identity of the receptor was deduced by expressing the neuropeptide Y-receptor-encoding cDNA in Chinese Hamster Ovary cells, which were subsequently challenged with size-fractionated Lymnaea brain extracts. An active peptide, selected on the basis of its ability to induce changes in cAMP levels, was purified to homogeneity, analysed by mass spectrometry and amino acid sequence determination, and turned out to be a Lymnaea homologue of neuropeptide Y.     

Downregulation of BDNF mRNA and protein in the rat hippocampus by corticosterone

Previously, we showed that corticosterone regulates BDNF mRNA levels in the hippocampus. In the present study, we have investigated the time course and dose-dependency of this effect at both the mRNA and the protein level. Corticosterone was administered in doses of 30 and 1000 microgram/kg b.w. subcutaneously to adrenalectomized animals. At 3, 6, 12 and 24 h after administration BDNF and trkB mRNA levels in hippocampal subfields were measured by in situ hybridization. Our results show a dose-dependent decrease in BDNF mRNA in dentate gyrus and CA1 at 3 h. After the high dose, this decrease was 70% and 40% respectively. In addition, ELISA was performed to study if this downregulation is also detectable at the protein level. Hippocampal tissue was used from adrenalectomized animals which had received 1000 microgram/kg b.w. corticosterone 4 and 6 h before decapitation. At both time points, a decrease in BDNF protein was observed; 17% at 4 h and 14% at 6 h after corticosterone, as compared to the vehicle injected controls. TrkB mRNA levels were not affected by corticosterone. However, between 6 and 24 h after treatment, increases in trkB mRNA were observed. In conclusion, we have found a transient, dose-dependent decrease in BDNF mRNA and protein in the hippocampus, which may underly changes in neuronal plasticity in the hippocampus after short-term changes in corticosterone concentrations.     

Chemistry of long-chain peroxy acids under laundry conditions

Peroxycarboxylic acids are increasingly used as bleaching agents for the laundering process. These peroxy acids can be added as such to the wash liquor or may be generated in situ by reaction of a precursor component with hydrogen peroxide. Bleaching effectiveness appears to be determined by a delicate balance of chemical reactions of peroxy acid with the staining dyes and the rate of peroxy acid decomposition under the prevailing conditions. To improve our understanding of the chemistry involved we have carried out a systematic study using a range of aromatic and aliphatic mono- and diperoxycarboxylic acids with various carbon chain lengths and degrees of branching. We investigated peroxy acid decomposition, bleaching of stained fabric and bleaching of a water-soluble dye, and showed that the alkyl chain length of the peroxy acids, the presence of detergent components and the pH of the medium are important factors. Combination of the kinetic data for decomposition and bleaching reactions allows the selection of structures and conditions for optimum performance. Presented at the AOCS meeting in New Orleans in May 1987.     

Identification of clay pans from AMSR-E passive microwave observations

A new methodology to derive the spatial distribution of clay pans from satellite microwave data is presented. Soil moisture has a different temporal signature in clay pans compared with other soils, which is directly reflected in the satellite-observed brightness temperatures. Three years of Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E) 6.9 GHz microwave observations were compiled and analysed over continental Australia to identify clay pans. This led to the development of a brightness temperature variance index (BTVI), which shows a strong spatial correspondence to an existing soil texture map and the ability to map clay pans for semi-arid regions. This simple method emphasizes the potential use of passive microwave remote sensing for soil type mapping.     

Efficacy of itraconazole in the prevention of fungal infections among neutropenic patients with hematologic malignancies and intensive chemotherapy. A double blind, placebo controlled study

We studied the efficacy and safety of itraconazole for the prevention of fungal infection in neutropenic patients given cytotoxic chemotherapy for hematologic malignancies. Patients were randomly allocated to receive either itraconazole (200 mg bd) or placebo in addition to oral amphotericin B until the patient either developed fungal infection or had completed antileukemic treatment. Forty six patients (83 neutropenic episodes) treated with itraconazole and 46 placebo treated patients (84 neutropenic episodes) were evaluable. No specific toxicity was noted. Nine fungal infections developed in the itraconazole group, of which four were histologically or microbiologically proven and 15 in the patients given placebo (eight proven) (p < 0.12). All these patients received IV amphotericin B. The incidence of Candida albicans infections tended to be lower in the itraconazole group, but overall, there was no measurable improvement in the prevention of fungal infections and mortality by itraconazole.     

Cold storage sensitizes hepatocytes to oxidative stress injury

Radiology administrators nationwide were surveyed to determine current drug administration practices in their imaging departments. The survey also obtained information about the educational backgrounds of radiologic technologists administering pharmaceuticals and the documentation procedures used by imaging departments. Survey results showed that 86% of responding institutions allow radiologic technologists to administer pharmaceuticals. However, the amount and type of education technologists received regarding drug administration was limited. In addition, the type of legal documentation regarding the administration of contrast media varied considerably among the responding institutions.