Growth of enterotoxigenic Bacillus cereus on salmon (Oncorhynchus nerka)

We previously demonstrated the widespread presence of enterotoxigenic Bacillus cereus in marine foods. In view of the widespread consumption of raw fish, we sought to determine the ability of this organism to grow on the surface of wild Alaskan salmon at abusive temperatures (12, 16, and 20°C), using an isolate able to produce elevated levels of hemolysin BL enterotoxin and nonhemolytic enterotoxin. An incubation temperature of 37°C for colony formation was found to be selective for B. cereus grown on salmon held for up to 24 h at each temperature. A fivefold increase in log CFU per gram was observed after 26 and 22 h at 16 and 20°C, respectively, while a >4-log CFU/g increase occurred on salmon held at 12°C for 48 h. Generation times of 169.7, 53.5, and 45.6 min were observed at 12, 16, and 20°C. Nonhemolytic enterotoxin was detected when levels of B. cereus were in excess of 10(8) CFU/g. Nisin, at concentrations of 1 and 15 m g/g of salmon, reduced levels of B. cereus 2.5- and 25-fold, respectively. Our results indicate that fresh salmon can serve as an excellent substrate for enterotoxigenic B. cereus and that this organism can reach levels associated with foodborne illness following moderate temperature abuse.     

In situ Dynamic Rheological Study of Polyacrylamide during Gelation Coupled with Mathematical Models of Viscosity Advancement

Acrylamide dynamic viscosity has been measured in aqueous solutions. Separate rheological measurements were performed on neat resins devoid of the curing agent over a range of shear rates to yield the initial resin viscosity. The gels were also characterized by sub‐ambient DSC to determine the phase structure as a function of formulation. The dynamic viscosity shows a marked sigmoidal behavior with a plateau viscosity. Mathematical interpretations of the gel time both by sigmoidal and power law models were comparable. The power law model allowed a direct determination of the gel time while the sigmoidal model yielded parameters associated with the initial viscosity, one associated with the plateau viscosity of the gel, and two time constants controlling the sharpness of the transition.

     

Late morbidity after esophagectomy for cancer: is partial esophagectomy preferred?

BACKGROUND: Several studies have highlighted the problem of back pain among helicopter pilots, but few have controlled for potential confounding factors in their analyses, or sought to examine the effects of back pain on operational readiness and flying performance. There have been no previous studies of the prevalence of back pain among Australian military pilots. METHODS: The prevalence, risk factors, and consequences of low back pain were assessed in a cross-sectional survey of 200 Australian military helicopter pilots by self-completion questionnaire. RESULTS: Responses were received from 131 (66%) of available pilots. The overall prevalence of reported back pain was 64% (95% CI 56%-72%), with a further 28% of pilots describing back discomfort while flying. More than half the pilots (55%) indicated that back pain had interfered with their concentration while flying, with 16% reporting that they had hurried flying missions because of pain. A minority of pilots (7%) had refused to fly because of back problems. After adjusting for age, education, BMI, posture and numbers of hours flown, multiple logistic regression modelling indicated that a prior history of back injury was the most significant predictor of back pain among rotary wing pilots (OR 2.63, 95% CI 1.11-6.23). CONCLUSIONS: We conclude that the prevalence of back pain in Australian military helicopter pilots is unacceptably high and may be limiting operational readiness, pilot performance, flying safety, and pilot health. Urgent attention needs to be given to improved ergonomic design in aircraft, and both back pain prevention and back injury rehabilitation programs.     

Mutagenesis and modeling of the neurotensin receptor NTR1. Identification of residues that are critical for binding SR 48692, a nonpeptide neurotensin antagonist

The two neurotensin receptor subtypes known to date, NTR1 and NTR2, belong to the family of G-protein-coupled receptors with seven putative transmembrane domains (TM). SR 48692, a nonpeptide neurotensin antagonist, is selective for the NTR1. In the present study we attempted, through mutagenesis and computer-assisted modeling, to identify residues in the rat NTR1 that are involved in antagonist binding and to provide a tentative molecular model of the SR 48692 binding site. The seven putative TMs of the NTR1 were defined by sequence comparison and alignment of bovine rhodopsin and G-protein-coupled receptors. Thirty-five amino acid residues within or flanking the TMs were mutated to alanine. Additional mutations were performed for basic residues. The wild type and mutant receptors were expressed in COS M6 cells and tested for their ability to bind 125I-NT and [3H]SR 48692. A tridimensional model of the SR 48692 binding site was constructed using frog rhodopsin as a template. SR 48692 was docked into the receptor, taking into account the mutagenesis data for orienting the antagonist. The model shows that the antagonist binding pocket lies near the extracellular side of the transmembrane helices within the first two helical turns. The data identify one residue in TM 4, three in TM 6, and four in TM 7 that are involved in SR 48692 binding. Two of these residues, Arg327 in TM 6 and Tyr351 in TM 7, play a key role in antagonist/receptor interactions. The former appears to form an ionic link with the carboxylic group of SR 48692, as further supported by structure-activity studies using SR 48692 analogs. The data also show that the agonist and antagonist binding sites in the rNTR1 are different and help formulate hypotheses as to the structural basis for the selectivity of SR 48692 toward the NTR1 and NTR2.     

Low temperature perception in plants: effects of cold on protein phosphorylation in cell-free extracts

Activities of prevalent protein phosphatases decreased by nearly 95% and those of individual protein kinases were differentially reduced at low temperature. Inhibition of phosphatase activity at temperatures below 12 degrees C resulted in marked hyperphosphorylation of a 58-kDa protein (PP58). The temperature threshold for hyperphosphorylation of PP58 coincided with the known threshold for cold-induced calcium influx. Since calcium influx is triggered by several environmental stresses, we propose that the observed direct effects of cold on the phosphorylation of specific proteins enable cells to couple a shared calcium signal to a cold-specific transduction pathway.     

Study of the cardiorespiratory response and chronotropic function after correction of tetralogy of Fallot. Important role of residual pulmonary regurgitation

The pathogenic O1 Amazonia variant of Vibrio cholerae has been shown previously to have a cytotoxin acting on cultured Vero and Y-1 cells, and to lack important virulence factors such as the cholera toxin (Coelho et al. 1995a). This study extends the molecular analysis of the Amazonia strains, detecting the presence of the toxR gene, with a very similar sequence to that of the E1 Tor and classical biotypes. The outer membrane proteins are analyzed, detecting a variation among the group of Amazonia strains, with three different patterns found. As a by-product of this work a polymerase chain reaction fragment was sequenced, reading part of the sequence of the Lon protease of the Amazonia strains. This gene was not previously described in V. cholerae, but its sequence is present in the TIGR database specific for this species.     

Propagating systems of dense linear integer constraints

In interval propagation approaches to solving nonlinear constraints over reals it is common to build stronger propagators from systems of linear equations. This, as far as we are aware, is not pursued for integer finite domain propagation. In this paper we show how we use interval Gauss–Jordan elimination to build stronger propagators for an integer propagation solver. In a similar fashion we present an interval Fourier elimination preconditioning technique to generate redundant linear constraints from a system of linear inequalities. We show how to convert the resulting interval propagators into integer propagators. This allows us to use existing integer solvers. We give experiments that show how these preconditioning techniques can improve propagation performance on dense systems.     

Six Decades of Research on Human Fetal Gonadal Steroids

Human fetal gonads acquire endocrine steroidogenic capabilities early during their differentiation. Genetic studies show that this endocrine function plays a central role in the sexually dimorphic development of the external genitalia during fetal development. When this endocrine function is dysregulated, congenital malformations and pathologies are the result. In this review, we explain how the current knowledge of steroidogenesis in human fetal gonads has benefited from both the technological advances in steroid measurements and the assembly of detailed knowledge of steroidogenesis machinery and its expression in human fetal gonads. We summarise how the conversion of radiolabelled steroid precursors, antibody-based assays, mass spectrometry, ultrastructural studies, and the in situ labelling of proteins and mRNA have all provided complementary information. In this review, our discussion goes beyond the debate on recommendations concerning the best choice between the different available technologies, and their degrees of reproducibility and sensitivity. The available technologies and techniques can be used for different purposes and, as long as all quality controls are rigorously employed, the question is how to maximise the generation of robust, reproducible data on steroid hormones and their crucial roles in human fetal development and subsequent functions.     

Chiral Phosphoric Acid‐Catalyzed Enantioselective Aza‐Friedel–Crafts Alkylation of Indoles with γ‐Hydroxy‐γ‐lactams

An enantioselective aza‐Friedel–Crafts reaction of indoles with γ‐hydroxy‐γ‐lactams using a chiral phosphoric acid catalyst is reported. The approach described herein provides an efficient access to 5‐indolylpyrrolidinones in good to quantitative yields and excellent enantioselectivities (up to >99% ee). The results suggest that the reaction may proceed via N‐acyliminium intermediates associated with the chiral phosphoric acid anion.     

Extended equivalent linear model (X-ELM) to assess liquefaction triggering: Application to the City of Urayasu during the 2011 Tohoku earthquake

This paper proposes a hybrid iterative approach to evaluating the liquefaction potential and settlements when liquefaction is not triggered for a saturated sand deposit subjected to seismic motion. The proposed method is a combination of an equivalent linear dynamic analysis and an empirical pore pressure build-up model. The two concepts are combined to account for the increase of pore-water pressure in the dynamic response. This extended equivalent linear model, or X-ELM, introduces a parameter $\chi$ identified by means of an extensive set of computations and observations. The approach has been validated in the case of Urayasu City during the 2011 Great East Japan Earthquake. The X-ELM enables the assessment of the triggering of the soil liquefaction of 12 representative soil profiles, namely, four profiles representing non-liquefied grounds in the old town of Urayasu and eight profiles representing the liquefaction-prone grounds in the reclaimed area of the city. The X-ELM computed areas of triggered liquefaction or non-liquefaction are found to be in good agreement with qualitative observations and in-situ measured responses.