Psychological correlates of cancer.

Administered the Recent Life Changes Questionnaire and the Tennessee Self-Concept Scale to 30 male lung cancer patients, 30 male emphysema patients, and 30 male well controls. Data suggest that there are definite indications of distinctive personality characteristics possessed by people who have cancer, which may have been characteristic of those people before their illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of acid dextrinisation on enzyme-resistant starch content in extruded maize starch

The enzyme-resistant starch (ERS) content in processed high amylose and regular maize starches has been studied, with and without acid dextrinisation. The physicochemical and structural characteristics of the starches were analysed using a variety of techniques. The increase in ERS in high amylose maize starch with dextrinisation was related to the formation of a critical molecular weight fraction (MW ∼ 20,000) that could rearrange structurally. Further dextrinisation reduced the processed starch MW to below where it could still form ERS. Regular maize starch containing less than 30% amylose did not increase its resistance to amylase digestibility with acid dextrinisation, probably due to impairment of amylose rearrangement by the numerous branched amylopectin chains. The ERS, which is likely to form during the enzyme-digestion process, is a linear molecule with a maximum degree of polymerisation (DP) of 30, irrespective of the starch source, processing conditions applied or type and amount of acid used.     

Impact of bacterial stress and biofilm-forming ability on transfer of surface-dried Listeria monocytogenes during slicing of delicatessen meats

Listeria monocytogenes contamination of delicatessen slicer blades can lead to cross-contamination of luncheon meats. A cocktail of 3 strong or 3 weak biofilm-forming strains of L. monocytogenes suspended in turkey slurry was used to inoculate stainless steel delicatessen slicer blades at a level of 6 log CFU/blade. The cocktails were used with or without injury (cold-shocked at 4 degrees C for 2 h, or chlorine-injured at 100 ppm for 1 min). Inoculated blades were held at 22 degrees C/78+/-2% relative humidity for 6 and 24 h, before being used to generate 30 slices from chubs of roast turkey breast or Genoa salami. Slices (25 g) were diluted 1:5 in University of Vermont Medium, homogenized by stomaching and then pour-plated using tryptose phosphate agar supplemented with esculin and ferric ammonium citrate. Greater cumulative transfer to the 30 slices was seen for the strong (3.62 log CFU) as opposed to weak biofilm-forming cocktails (3.12 log CFU) with transfer also significantly greater to turkey (3.61 log CFU) than to salami (3.12 log CFU). Among the three treatments, cold-shock significantly increased subsequent L. monocytogenes transfer (3.69 log CFU) compared to the uninjured control (3.30 log CFU) and chlorine-injury (3.12 log CFU). Significantly greater transfer was also seen for blades used after 6 as opposed to 24 h of incubation. Differences in product composition and survival of L. monocytogenes, as seen via viability staining, are likely reasons for these observed differences in transfer.     

Altered hydrophobicity and membrane composition in stress-adapted Listeria innocua

Exposure of Listeria innocua to acid and starvation stress decreases sensitivity to the quaternary ammonium compound cetrimide, whereas exposure to cold and heat stress increases sensitivity to this compound. Changes in membrane lipids occur in response to certain types of stress, and these changes likely impact cell sensitivity to chemical sanitizers. The present study included an assessment of the effects of acid, starvation, cold, and heat stress on net cell hydrophobicity and fatty acid composition in L. innocua. Net cell hydrophobicity was determined by measuring absorbance of stress-adapted cell suspensions after partitioning with the nonpolar solvent n-hexadecane. Free fatty acids extracted from stress-adapted suspensions were analyzed by gas chromatography. Adaptation to acid and starvation increased net cell hydrophobicity and decreased membrane fluidity, which was correlated with reductions in anteiso fatty acids and in ratios of anteiso to iso fatty acids. Conversely, cold-stressed populations exhibited decreased net cell hydrophobicity and increased membrane fluidity with a corresponding increase in C15:C17 and anteiso:iso ratios and in C18 unsaturated fatty acids. No significant changes in net cell hydrophobicity or membrane fluidity were observed in heat-stressed cells, which exhibited increased sensitivity to cetrimide, suggesting another mechanism for altered cell sensitivity. These findings indicate that the efficacy of cetrimide against Listeria is partially dependent on the physiological state of the organism following exposure to various environmental stresses.     

Survey of vomitoxin contamination of the 1980 white winter wheat crop in ontario,canada

During the summer of 1980, there was a great deal of rainfall and high humidity in southwestern Ontario. Sprouting of the kernels on plants in the field and pink discoloration down-graded the white winter wheat crop. Samples were submitted to Agriculture Canada from elevators and boats loading wheat for export. Chemical analyses indicated low levels of vomitoxin, with some analytical results as high as 8.5 ppm. A series of feeding trials was initiated with contaminated wheat (1.0 ppm vomitoxin) to determine effects on swine and poultry. Swine diets containing 0.3 and 0.7 ppm vomitoxin resulted in decreased feed consumption and weight gains. Poultry were fed similar levels of vomitoxin without any serious effects. Gross examination of internal organs at the termination of the subacute studies revealed no apparent toxic effects. Several farmers reported feed refusal, vomiting and death in their livestock. Chemical analyses, in general, revealed relatively low levels of vomitoxin. In one case, the level of vomitoxin (0.95 ppm) in the feed was high enough to be a possible contributing factor in the observed ill effects.     

Morphology and crack resistance behavior of binary block copolymer blends

Fracture behavior of binary blends comprising of styrene-butadiene block copolymers having star and triblock architectures was studied via instrumented Charpy impact test. The toughness of the ductile blends was characterized by dynamic crack resistance curves (R-curves).This study represents a systematic investigation of crack resistance behavior of nanometer structured binary block copolymer blends and the development of a new material with a combination of high toughness and transparency, usually not observed in incompatible polymer blends. While the lamellar star block copolymer shows an elastic behavior (small-scale yielding and unstable crack growth), adding of 20 wt% of the triblock copolymer leads to a stable crack growth and at 60 wt% of the triblock copolymer the strong increase of toughness values indicate a tough/high-impact transition, demonstrating the existence of novel toughening concepts for polymers based on nanometer structured materials.     

Development of high-repetition-rate laser pump/x-ray probe methodologies for synchrotron facilities

We describe our implementation of a high repetition rate (54 kHz-6.5 MHz), high power (>10 W), laser system at the 7ID beamline at the Advanced Photon Source for laser pump/x-ray probe studies of optically driven molecular processes. Laser pulses at 1.06 μm wavelength and variable duration (10 or 130 ps) are synchronized to the storage ring rf signal to a precision of ~250 fs rms. Frequency doubling and tripling of the laser radiation using nonlinear optical techniques have been applied to generate 532 and 355 nm light. We demonstrate that by combining a microfocused x-ray probe with focused optical laser radiation the requisite fluence (with <10 μJ/pulse) for efficient optical excitation can be readily achieved with a compact and commercial laser system at megahertz repetition rates. We present results showing the time-evolution of near-edge x-ray spectra of a well-studied, laser-excited metalloporphyrin, Ni(II)-tetramesitylporphyrin. The use of high repetition rate, short pulse lasers as pump sources will dramatically enhance the duty cycle and efficiency in data acquisition and hence capabilities for laser-pump/x-ray probe studies of ultrafast structural dynamics at synchrotron sources.     

Engineered Biomolecular Recognition of RDX by Using a Thermostable Alcohol Dehydrogenase as a Protein Scaffold

There are many biotechnology applications that would benefit from simple, stable proteins with engineered biomolecular recognition. Here, we explored the hypothesis that a thermostable alcohol dehydrogenase (AdhD from Pyrococcus furiosus) could be engineered to bind a small molecule instead of a cofactor or molecules involved in the catalytic transition state. We chose the explosive molecule 1,3,5‐trinitro‐1,3,5‐triazine (royal demolition explosive, RDX) as a proof‐of‐concept. Its low solubility in water was exploited for immobilization for biopanning by using ribosome display. Docking simulations were used to identify two potential binding sites in AdhD, and a randomized library focused on tyrosine or serine mutations was used to determine that RDX was binding in the substrate binding pocket of the enzyme. A fully randomized binding pocket library was selected, and affinity maturation by error‐prone PCR led to the identification of a mutant (EP‐16) that gained the ability to bind RDX with an affinity of (73±11) μm . These results underscore the way in which thermostable enzymes can be useful scaffolds for expanding the biomolecular recognition toolbox.     

Senftleben-Beenakker thermal conductivity effect apparatus

An apparatus for measuring the influence of magnetic fields on the thermal conductivity of gases, the Senftleben-Beenakker effect, is described. Conventional 'cold finger type' cooling with appropriate cryogenic fluids is utilized with a helium exchange gas chamber to establish the general temperature level of the cell holder. Automatic temperature control of the trim heater maintains the desired temperature to +/-10(-3) degrees C in the 77-300 K range. A concentric cylinder cell adaptable for use with either conventional electromagnet or superconducting solenoid is described. The use of thin Mylar polyester film end seals minimizes cell 'end effect' corrections and provides a resolution of 5x10(-6) in gas thermal conductivity.