Inhibition Studies of Mycobacterium tuberculosis Salicylate Synthase (MbtI)

Mycobacterium tuberculosis salicylate synthase (MbtI), a member of the chorismate‐utilizing enzyme family, catalyses the first committed step in the biosynthesis of the siderophore mycobactin T. This complex secondary metabolite is essential for both virulence and survival of M. tuberculosis, the etiological agent of tuberculosis (TB). It is therefore anticipated that inhibitors of this enzyme may serve as TB therapies with a novel mode of action. Herein we describe the first inhibition study of M. tuberculosis MbtI using a library of functionalized benzoate‐based inhibitors designed to mimic the substrate (chorismate) and intermediate (isochorismate) of the MbtI‐catalyzed reaction. The most potent inhibitors prepared were those designed to mimic the enzyme intermediate, isochorismate. These compounds, based on a 2,3‐dihydroxybenzoate scaffold, proved to be low‐micromolar inhibitors of MbtI. The most potent inhibitors in this series possessed hydrophobic enol ether side chains at C3 in place of the enol‐pyruvyl side chain found in chorismate and isochorismate.     

Assessment of biogas potential hazards

Biogas produced from anaerobic fermentation of organic substances represents an alternative renewable energy source. Its utilization would contribute to substantial reduction of the solid waste volume in land-filling and incineration. Biogas so produced could be utilized on site or it could be injected into the natural gas distribution network. Microbiological and chemical compositions of different biogas types were determined in order to conduct qualitative and quantitative risk assessments of the potential health hazards associated with biogas use for cooking. Biogas types that could be allowed for injection in the natural gas pipelines were listed with recommendations, while outlining the European biogas injection policy. Results indicated that the injection of the processed biogas in the distribution network did not present any additional chemical or microbiological risk to consumers when compared to natural gas, provided that the biogas resulted from the fermentation of non-dangerous waste. However, since this study did not examine the microbiological and chemical composition of biogas originating from wastewater sludges and/or industrial wastes, the injection of this type of biogas into the gas distribution network should not be allowed unless a similar risk evaluation study is conducted for each case.     

Psychosocial predictors of employment status among men living with spinal cord injury.

Objective: To explore the relationship between employment status and community access, perceived community discrimination, social support from significant others, depressive symptoms, and gender-related variables for 83 men living with spinal cord injury. Study Design: Correlational research. Setting: Internet-based investigation employing spinal cord injury listservs. Main Outcome Measure: Participant employment status. Results: A forced-entry hierarchical logistic regression indicated that means of injury, community access and perceived community discrimination, social support from significant others, depressive symptoms, and men’s adherence to masculine norms for primacy of work, self-reliance, and emotional control significantly predicted employment status. Conclusions: Psychosocial variables such as community access, perceived discrimination, social support from significant others, depressive symptoms, and gender identity represent important and understudied predictors of employment status among men living with spinal cord injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alumina–Aluminide Alloys (3A) Technology: I, Model Development

The general reaction behavior of the 3A process under the thermal explosion mode of synthesis has been investigated via a continuum model. The continuum model uses mass and energy balances to predict temperature difference ( T _s,avg− T _f) curves, as well as profile curves of the reactant conversions and sample temperature. In particular, the effect of the dimensionless parameters associated with the rate of local heat generation (β, the thermicity factor), the activation energy (γ, the Arrhenius number), the rate of heat redistribution (α, the modified thermal diffusivity), the rate of heat transfer by convection (Bi, the Biot number or convective heat transfer parameter), and the rate of heat transfer by radiation (Ω, the radiative heat transfer parameter) were investigated. Conditions to control the reaction process, which should produce high-density final products, were determined. It was found that the overall maximum temperature may be reduced for high γ, low β, high α, and high Bi and Ω. In terms of processing conditions, this may be obtained by reducing the initial reactant concentrations, optimizing the particle size, using small sample sizes and high compaction pressure, and increasing the heat loss by using a high thermal conductivity inert gas.     

Lower region: A new cue for figure-ground assignment.

Figure-ground assignment is an important visual process; humans recognize, attend to, and act on figures, not backgrounds. There are many visual cues for figure-ground assignment. A new cue to figure-ground assignment, called lower region, is presented: Regions in the lower portion of a stimulus array appear more figurelike than regions in the upper portion of the display. This phenomenon was explored, and it was demonstrated that the lower-region preference is not influenced by contrast, eye movements, or voluntary spatial attention. It was found that the lower region is defined relative to the stimulus display, linking the lower-region preference to pictorial depth perception cues. The results are discussed in terms of the environmental regularities that this new figure-ground cue may reflect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analytik von Phosphorsäurepartialestern

Analytic of Phosphoric Acid Partial Esters Phosphoric acid partial esters are best synthesized by reaction of fatty alcohol with P₂O₅. The chosen mol ratio of fatty alcohol and P₂O₅ determines the amounts of mono-, di- and trialkylester, of oligomeric esters, of free fatty alcohol and of phosphoric acid. Several methods are used for the characterisation and determination of the individual components, the potentiometric titration, the ³¹P-nuclear magnetic resonance, the gel permeation chromatography, the ion chromatography and the supercritical fluid chromatography. The combination of all the results of the applied methods provides the key to the composition of the phosphoric acid ester. The results of the analysis are checked by a phosphorus calculation. This analytical procedure can be applied to phosphoric acid partial esters in the acid and salt form. The analysis of alkylethoxyphosphoric esters is done with the exclusion of the chromatographic methods.     

Grouped arrays versus object-based representations: Reply to Kramer et al. (1997).

An important issue in attention research concerns the representational format from which attention selects. S. P. Vecera and M. J. Farah (see record 1994-32352-001) presented results that they argued demonstrated attentional selection from a spatially invariant object representation. In their comment, A. F. Kramer, T. A. Weber, and S. E. Watson (see record 84-18014) questioned the interpretation of these results, and they presented evidence consistent with selection from a grouped location-based representation. In this reply, the author argues that although an absence of spatial, or distance, effects may be ambiguous as to whether attention is selecting from an object-based representation or from a location-based representation, there are computational considerations that favor object-based selection in certain tasks. The author concludes with a discussion of how object-based and location-based representations might interact with one another, thereby providing a possible explanation of Kramer et al.'s results. Such an account may lead to an understanding of how multiple forms of attentional selection may coexist in the visual system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention does not require preattentive grouping.

Does spatial attention follow a full preattentive analysis of the visual field, or can attention select from ungrouped regions of the visual field? We addressed this question by testing an apperceptive agnosic patient, J. W., in tasks involving both spatial selection and preattentive grouping. Results suggest that J. W. had intact spatial attention: He was faster to detect targets appearing at cued locations relative to targets appearing at uncued locations. However, his preattentive processes were severely disrupted. Gestalt grouping and symmetry perception, both thought to involve preattentive processes, were impaired in J. W. Also, he could not use gestalt grouping cues to guide spatial attention. These results suggest that spatial attention is not completely dependent on preattentive grouping processes. We argue that preattentive grouping processes and spatial attention may mutually constrain one another in guiding the attentional selection of visual stimuli but that these 2 processes are isolated from one another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)