Screening and characterization of microorganisms with glutaryl-7ADCA acylase activity

A screening of microorganisms producing glutaryl-7ADCA acylase, an enzyme able to hydrolyse glutaric acid selectively from glutaryl-3-deacetoxy-7-aminocephalosporanic acid (glutaryl-7ADCA), has been carried out in soil samples. Five microorganisms expressing acylase activity were isolated and classified as Bacillus cereus, Achromobacter xylosooxidans, Bacillus sp., Pseudomonas sp. and Pseudomonas paucimobilis. The screening was carried out by preparing enrichment cultures containing glutaryl-7-ADCA or cephalosporin C as the selective carbon source. Four model compounds (adipoyl-, glutamyl- and glutaryl-p-nitroanilide and glutarylcoumarin), mimicking the glutaryl-7ADCA beta-lactam moiety, were synthesized as substrates suitable for the rapid screening of the microorganisms (2500) isolated from the enrichment cultures. A total of 300 strains were active on the model substrates and only 5 displayed acylase activity on glutaryl-7ADCA. The fermentation parameters, such as pH and inducer concentration, for the optimal acylase expression and acylase specificity towards the model substrates were different for each strain.     

Native valve infective endocarditis in elderly and younger adult patients: comparison of clinical features and outcomes with use of the Duke criteria and the Duke Endocarditis Database

The effect of age on the presentation and outcome of infective endocarditis (IE) is unclear. Many of the available data are based on analyses of mixed populations of patients including intravenous drug users or those with prosthetic valve endocarditis or native valve IE. We used the Duke criteria to compare the characteristics of 44 episodes of definite native valve IE in elderly patients (> 64 years old) with the characteristics of 64 similarly defined episodes of native valve IE in younger, nonintravenous-drug-using adult patients (> 29 years and < 60 years old). Our data suggest that the clinical presentation, characteristics, and outcome of native valve IE are similar for elderly patients and younger adult patients, although elderly patients were hospitalized an average of 12 days longer. Although we found that the occurrence of renal failure and cerebral embolism during an episode of IE was associated with higher rates of death (odds ratios, 4.8 and 4.0, respectively), age was not a significant contributor to mortality.     

Structure,stoichiometry and phase purity of strontium-doped lanthanum manganite powders

Strontium-doped lanthanum manganite La_{1, x} Sr _x MnO₃ (LSM) is characterized by hexagonal-rhombohedral distorted perovskite-type structure, deriving from the ideal cubic symmetry through rotation of the [MnO₆] octahedra around the ternary axis. The extent of distortion and unit cell volume depend on Sr content. The linear variation of the unit cell volume, observed in the compositional range 0.1 x 0.5, can be effectively used for determining the stoichiometry of LSM. A procedure for the quantitative analysis of segregated impurities (La₂O₃ and Mn₃O₄) based on X-ray powder diffraction analysis, has also been developed.     

A Comparison of Short-Term Water Demand Forecasting Models

Water Resources Management - This paper presents a comparison of different short-term water demand forecasting models. The comparison regards six models that differ in terms of: forecasting...     

Tryptophan and tonic immobility in chickens: Effects of dietary and systemic manipulations.

Consistent with a serotonergic-midbrain raphe model of tonic immobility, 4 experiments designed to evoke changes in serum tryptophan produced reliable effects on the duration of the response in a total of 114 Production Red chickens. Systemic injections of tryptophan, the dietary precursor of serotonin, led to a dose-dependent increase in immobility, with optimal effects observed within 30 min after injection. Dietary depletion of endogenous tryptophan attenuated the duration of immobility, and a diet completely free of tryptophan, but supplemented with niacin, practically abolished the reaction. Dietary replacement of tryptophan reinstated the response. In a 5th experiment with 20 Ss, tryptamine, an alternative metabolic by-product of tryptophan, had no effect on immobility. Data are discussed in light of evidence showing serotonergic involvement in tonic immobility. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quasiparticle correction for electronic transport in molecular wires

In this paper we present calculations of ballistic transport in molecular wires. The calculations are performed using an approximated version of the GW correction in the plasmon-pole framework, which is used to improve the starting Density Functional Theory energy spectrum of the molecule between metallic leads. We show that this correction reduces the error of the correlation part for the electron energy. Finally a model with complex bands is implemented in order to get the damping regime for long polymers.     

Effect of PLL frequency synthesizer in FSK frequency-hoppedcommunications

Synthesizer transient and spur effects in an frequency-shift-keying frequency-hopped system are investigated. Models for transient analysis are developed, and resulting degradations to performance are computed. Compensation methods, such as ping-ponging multiple synthesizers and gating symbol detectors, are considered. A spur analysis is presented, and the overall output effects on hopping spectrum and demodulation are shown. Methods to bound degradation in terms of number and strength of spur lines are presented     

The effect of radiopacifiers agents on pH,calcium release,radiopacity, and antimicrobial properties of different calcium hydroxide dressings

The aim of this study was to evaluate the antimicrobial activity, pH level, calcium ion release, and radiopacity of calcium hydroxide pastes associated with three radiopacifying agents (iodoform, zinc oxide, and barium sulfate). For the pH and calcium release tests, 45 acrylic teeth were utilized and immersed in ultrapure water. After 24 h, 72 h, and 7 days the solution was analyzed by using a pH meter and an atomic absorption spectrophotometer. Polyethylene tubes filled with the pastes were used to perform the radiopacity test. For the antimicrobial test, 25 dentin specimens were infected intraorally in order to induce the biofilm colonization and treated with the pastes for 7 days. The Live/Dead technique and a confocal microscope were used to obtain the ratio of live cells. Parametric and nonparametric statistical tests were performed to show differences among the groups (P < 0.05). The pH analysis at 7 days showed significant differences (P < 0.05) among the groups. No differences among the pastes were found in the calcium release test on the 7th day (P > 0.05). The calcium hydroxide/iodoform samples had the highest radiopacity and antimicrobial activity against the biofilm‐infected dentin in comparison to the other pastes (P < 0.05). Calcium hydroxide mixed with 17% iodoform and 35% propylene glycol into a paste had the highest pH, calcium ion release, radiopacity, and the greatest antimicrobial action versus similar samples mixed with BaSO4 or ZnO. Microsc. Res. Tech. 78:620–625, 2015. © 2015 Wiley Periodicals, Inc.