Use of green fluorescent protein expressing Salmonella Stanley to investigate survival, spatial location, and control on alfalfa sprouts.

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 10(7) CFU/ml) for 5 min at 22 degrees C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12 microm within intact sprout tissue. An initial population of ca. 10(4) CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22 degrees C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4 degrees C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 10(5) CFU/g Salmonella Stanley to the noncontaminated sprouts.     

Impaired or accelerated aggregation of proteins in sterilised milk by adding surfactants

The effect of small-molecule surfactants on the stability of sterilised milk (with added sterol esters) was determined by measurement of the sensitivity towards renneting, and of particle size upon freeze-thaw treatment. Water-soluble surfactants like diacetyl tartaric esters of monoglycerides and sodium stearoyl lactylates reduced freeze-thaw stability and the rate of renneting. Oil-soluble surfactants, like monoglycerides and citric acid esters of monoglycerides had an opposite effect. Water-soluble surfactants could coat the proteins and render casein micelles more dense; hence they could reduce age gelation through reduced access by enzymes. The same surfactants, however, also coated the outside of the micelles and rendered them more hydrophobic, which resulted in reduced colloidal stability. The oil-soluble surfactants had an opposite effect: they accelerated renneting, and improved colloidal stability. Because of the latter they are alternatives to polyphosphates or carrageenan. We also found indications that polyphosphates increased protein-enzyme repulsion.     

Hydrogenation of HgCdTe epilayers on Si substrates using glow discharge plasma

Preliminary results of a study of the hydrogenation of HgCdTe epilayers grown by molecular beam epitaxy on Si substrates using a glow-discharge plasma are presented. The aim of the program is to employ H to passivate the detrimental opto-electronic effects of threading dislocations present in the HgCdTe epilayers. Secondary ion mass spectroscopy depth profiling has been performed to characterize ¹H and ²H incorporation. It has been found that H can be controllably incorporated in HgCdTe epilayers to levels in the 10¹⁴ cm⁻³ to 10¹⁸ cm⁻³ range while maintaining the sample at temperatures lower than 60°C. Profiles indicate that H accumulates in regions of known high defect density or in highly strained regions. Analysis of the H depth profile data indicates that the current density-time product is a good figure of merit to predict the H levels in the HgCdTe epilayer. There are progressive differences in the ¹H and ²H uptake efficiencies as a function of depth. Magneto-Hall measurements show consistently higher mobilities at low temperatures for majority carriers in hydrogenated samples.     

Silk Hydrogel Microfibers for Biomimetic Fibrous Material Design

Fiber units are conserved design motifs that bestow intrinsic stiffness to biological tissues. Collagen fibrils are the fundamental unit of fibrous tissues with controlled assembly and multiscale structure‐function properties. Characteristic non‐linear tissue response is afforded through energy dissipation at the stiff‐soft interfaces of fibril collagen and extrafibrillar matrix components. The goal of this research is to develop a 3D silk hydrogel microfiber platform with bioinspired toughening mechanisms. Batch fabrication and post‐processing renders fibers that can be handled and with tunable features, as well as loading of components to improve material responses. Matrix loading of a glycoprotein, bovine serum albumin (BSA), adds a primary defense mechanism to material failure in the form of sacrificial bonds. This enables nano‐ to micro‐scale rearrangement with strain and improved fiber toughness compared to silk‐only fibers. Further biomimicry is added via matrix loading of a biosilica precursor peptide, R5, enabling biomineralization in the form of silicification. Inorganic mineral deposition of Silk‐BSA‐R5 hydrogel microfibers provides a fibrous scaffold for applications that require fibril‐mineral interfaces for load transduction. This microfiber platform introduces a methodology for meticulous fibrous scaffold design with biomimetic fibril hierarchy, toughening mechanisms, and loading capabilities for systematic tissue engineering applications.     

Compact all-solid-state high repetition rate tunable ultraviolet source for airborne atmospheric gas sensing

Abstract

A diode-pumped, all-solid-state, high pulse repetition rate, tunable source of UV radiation is presented. The system is compact, has low power requirements and is suitable for the in situ monitoring of important atmospheric species from an airborne platform. At 3 kHz pulse repetition rate, up to 0.42 ± 0.02 mW of UV radiation was generated and the tuning range extended from ～282 nm to 292 nm. The bandwidth was ≤0.6nm and each pulse had a FWHM duration of 16.0 ± 1.4 ns. The stability of the output was 13% pulse-to-pulse and 4% for an average power measurement. The performance of the system is compared to theoretical expectations.     

Frequency and predictors of relationship dissolution in a community sample in England.

The frequency and predictors of separation were examined in a large community sample in the United Kingdom. Over an approximately 2-year time span, from pregnancy to 21 months postnatal, the rates of change varied greatly among different family types, from 5% in families with 2 biological parents and no stepchildren to 38% in complex stepfamilies and 43% in stepmother families. Multivariate logistic regression analyses indicated that separation in 2-parent families was predicted by a complex combination of individual and life-course history variables, including number of previous relationships, cohabiting status, poor relationship quality, low socioeconomic status and younger age. The findings are discussed in the context of previous psychological and sociological studies, and the substantial overlap among identified risk factors is highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of hearsay witness age in a child sexual assault trial.

This study investigated the effect of a hearsay witness on perceptions of an alleged victim in a sexual assault trial. Male and female participants read a fictional criminal court case summary involving a sexual assault, in which a 7-, 16-, or 25-year-old hearsay witness testified on behalf of a 6- or 15-year-old alleged victim. The prosecution case included the testimony of 1 primary witness: the alleged child victim, a hearsay witness, or a clinical psychologist. A post hoc control group had no primary witness. The hearsay witness led to as much support of the alleged victim as the child and the expert witness and more support than the control group. Women were consistently more supportive of the alleged victim than men. A 3-way interaction of age of hearsay witness, age of alleged victim, and sex of participant was discussed in terms of the effect of these factors on how mock jurors use hearsay testimony in a child sexual assault trial. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Parametric Study of the Synthesis of 4,4′,5,5′,7,7′-Hexanitro-1,1′-Binaphthyl

Conditions for the synthesis of 4,4′,5,5′,7,7′-hexanitrobinaphthyl( I ) from 1,1′-binaphthyl have been investigated. It has been found that( I ) can be prepared in 50% yield in a two-stage nitration process.     

Studies on 2,4,6-Trinitrophenyl Substituted Naphthalenes. Part II. Synthesis of nitro- and polynitro-1-(2,4,6-trinitrophenyl)naphthalenes

Mononitro-, dinitro-, trinitro- and tetranitro-derivatives of 1-(2,4,6-trinitrophenyl)naphthalene have been synthesised using a variety of nitration procedures. The mononitro- and dinitro-derivatives have also been synthesised from 1-bromonaphthalene and 1-nitronaphthalene via a combination of bromination, nitration and Ullmann reactions.     

Structure and stability of heat-treated concentrated dairy-protein-stabilised oil-in-water emulsions: A stability map characterisation approach

Emulsion instabilities such as depletion flocculation, coalescence, aggregation and heat-induced protein aggregation may be detrimental to the production of sterilised food emulsions. The type and the amount of protein present in the continuous phase and at the oil–water interface are crucial in the design of emulsions with appropriate stability. In this study, four oil-in-water model emulsion systems (pH 6.8–7.0) were formulated, characterised and categorised according to the potential interactions between protein-coated or surfactant-coated emulsion droplets and non-adsorbed proteins present in the continuous phase. The heat stability, the creaming behaviour and the flow behaviour of the model emulsions were influenced by both the emulsifier type and the type of protein in the continuous phase. The results suggest that this stability map approach of predicting droplet–droplet, droplet–protein and protein–protein interactions will be useful for the future design of heat-stable emulsion-based beverages with good creaming stability at high protein concentrations.