Synthesis,Biological Evaluation and 2D-QSAR Study of Halophenyl Bis-Hydrazones as Antimicrobial and Antitubercular Agents

In continuation of our endeavor towards the development of potent and effective antimicrobial agents, three series of halophenyl bis-hydrazones (14a–n, 16a–d, 17a and 17b) were synthesized and evaluated for their potential antibacterial, antifungal and antimycobacterial activities. These efforts led to the identification of five molecules 14c, 14g, 16b, 17a and 17b (MIC range from 0.12 to 7.81 μg/mL) with broad antimicrobial activity against Mycobacterium tuberculosis; Aspergillus fumigates; Gram positive bacteria, Staphylococcus aureus, Streptococcus pneumonia, and Bacillis subtilis; and Gram negative bacteria, Salmonella typhimurium, Klebsiella pneumonia, and Escherichia coli. Three of the most active compounds, 16b, 17a and 17b, were also devoid of apparent cytotoxicity to lung cancer cell line A549. Amphotericin B and ciprofloxacin were used as references for antifungal and antibacterial screening, while isoniazid and pyrazinamide were used as references for antimycobacterial activity. Furthermore, three Quantitative Structure Activity Relationship (QSAR) models were built to explore the structural requirements controlling the different activities of the prepared bis-hydrazones.     

New Approach to Compare Glare and Light Characteristics of Conventional and Balloon Lighting Systems

With the increasing needs to adopt nighttime construction strategies in order to avoid disruption of traffic flow, state agencies are currently experimenting with a new class of light towers known as balloon lights. Compared to regular lighting tower, balloon lights have been reported to reduce glare significantly and to provide more uniform lighting conditions at the site. The objective of this study was to measure light and glare characteristics of two balloon lighting systems in the field. Glare and lighting characteristics of this new class of light towers were compared to a conventional lighting system. For this purpose, field measurements were made of the pavement luminance and the horizontal and vertical illuminances on a predefined experimental grid. Results of this study indicated that while being comparable in terms of wattage and luminous flux, the tested balloon light systems differed in terms of light and glare characteristics. In addition, while conventional light tower provided greater illuminance at the light source than balloon lights, the disability glare was greater for conventional light tower than balloon lights when mounted at the same height. Results of this study revealed that optimum conditions should be sought in the work zone, through which adequate lighting conditions are provided for workers while disability glare is kept below a safe threshold for drive-by motorists. Plotting the maximum veiling luminance ratio (disability glare) against the workable distance provides a simple approach to consider the two factors concurrently in the design of work zone lighting.     

Poly(vinyl alcohol)‐Based Film Potentially Suitable for Antimicrobial Packaging Applications

This work aimed at developing a thin and water‐resistant food‐grade poly(vinyl alcohol) (PVOH)‐based matrix able to swell when in contact with high moisture content food products without rupturing to release antimicrobial agents onto the food surface. This film was prepared by blending PVOH and 7.20% (wt/wt of PVOH) of poly(ethylene glycol) (PEG) with citric acid as crosslinking agent. The film‐forming solution was then casted onto a flat surface and the obtained film was 60 μm in thickness and showed a good transparency (close to T = 100%) in the visible region (400 to 700 nm). After immersion in water for 72 h at room temperature, the crosslinked matrix loses only 19.2% of its original weight (the percentage includes the amount of unreacted crosslinking agent, antimicrobial in itself). Water content, degree of swelling, and crosslinking density of the film prove that the presence of PEG diminishes the hydrophilic behavior of the material. Also the mechanical properties of the wet and dry film were assessed. Alongside this, 2.5% (wt/wt of dry film) of grapefruit seed extract (GSE), an antimicrobial agent, was added to the film‐forming solution just before casting and the ability of the plastic matrix to release the additive was then evaluated in vitro against 2 GSE‐susceptible microorganisms, Salmonella enteritidis and Listeria innocua. The results indicate that the developed matrix may be a promising food‐grade material for the incorporation of active substances.     

Finger management schemes for RAKE receivers with a minimum call drop criterion

We propose and analyze in this letter new finger management techniques which are applicable for RAKE receivers operating in the soft handover region. These schemes employ ?distributed? types of generalized selection combining (GSC) and minimum selection GSC schemes in order to minimize the impact of sudden connection loss of one of the active base stations. By accurately quantifying the average error rate, we show through numerical examples that our newly proposed distributed schemes offer a clear advantage in comparison with their conventional counterparts.     

The role of squalene synthetase in the inhibition of tetrahymanol biosynthesis by cholesterol inTetrahymena pyriformis

The biosynthesis of the triterpenoid alcohol tetrahymanol byTetrahymena pyriformis is rapidly inhibited by the addition of cholesterol to the growth medium. The primary site of this inhibition by cholesterol has been established to be at the level of the enzyme squalene synthetase. The protein synthesis inhibitor cycloheximide produces an identical decline in squalene synthetase activity to that of cholesterol and the half-life of the enzyme is about 50 minutes. No direct inhibition of the enzyme is observed and suggests that cholesterol inhibits the actual synthesis of the enzyme squalene synthetase. Farnesol is accumulated during in vitro incubations derived from cells grown in the presence of cholesterol or cycloheximide.