Lessons to learn about postmortem metabolism using the AMPKγ3(R200Q) mutation in the pig

The development of pork quality attributes - including color, water holding capacity, and texture - are controlled largely by the rate and extent of postmortem pH decline. In turn, pH decline is thought to follow the anaerobic degradation of glycogen to "lactic acid". The "Hampshire effect" or Rendement Napole (RN(-)) pig, which has elevated muscle glycogen, propagated the widespread use of "glycolytic potential" to describe muscle's capacity for postmortem glycolysis. Since the evolution of glycolytic potential, there have been great strides in molecular and technical capabilities. Hence, it must be appreciated that the RN(-) pig possesses a mutation in the gene encoding the AMP-activated protein kinase (AMPK) γ3 subunit, which results in a non-conservative amino acid substitution (R200Q). AMPK, a major energy sensor in skeletal muscle, influences enzyme activity, gene and protein expression, fiber type, and mitochondrial biogenesis. The utility of glycolytic potential as indicator of ultimate pH should be reevaluated in the context of the metabolic differences between AMPKγ3 mutated and normal muscle. Understanding the metabolism and energetics in AMPKγ3 mutated muscle may provide insight into the mechanisms influencing the rate and extent of postmortem metabolism.     

Self-assembled DNA-based fluorescence waveguide with selectable output

Using the principle of self-assembly, a fluorescence-based photonic network is constructed with one input and two spatially and spectrally distinct outputs. A hexagonal DNA nanoassembly is used as a scaffold to host both the input and output dyes. The use of DNA to host functional groups enables spatial resolution on the level of single base pairs, well below the wavelength of light. Communication between the input and output dyes is achieved through excitation energy transfer. Output selection is achieved by the addition of a mediator dye intercalating between the DNA base pairs transferring the excitation energy from input to output through energy hopping. This creates a tool for selective excitation energy transfer on the nanometer scale with spectral and spatial control. The ability to direct excitation energy in a controlled way on the nanometer scale is important for the incorporation of photochemical processes in nanotechnology.     

Method of isolation, rate of postmortem metabolism, and myosin heavy chain isoform composition influence ATPase activity of isolated porcine myofibrils

The objective of this study was to determine the influence of myofibril isolation procedures and myosin heavy chain (MyHC) isoform composition on myofibrillar ATPase activity as related to postmortem muscle metabolism. Myofibrils from the red (RST) and white (WST) portions of semitendinosus muscles were isolated using two different methods (A and B) at 3 min and 24 h postmortem in control (NS) and electrically stimulated (ES) pork carcasses. Comparison of the relative MyHC isoform profiles between the two different myofibril isolation methods and myosin extracts from the RST and WST at 3 min showed that method B myofibrils were more similar to the myosin extract than method A. Myofibrillar ATPase activity remained constant or increased (P<0.01) from 3 min to 24 h postmortem in NS carcasses and decreased (P<0.0001) in ES carcasses. From the RST, method A myofibrils had higher (P<0.0001) ATPase activity compared to method B across sampling time and carcass treatment. In the WST, method A myofibrils had lower (P<0.01) activity at 3 min, were not different at 24 h in NS carcasses, but had higher (P<0.05) activity at 24 h in ES carcasses versus method B myofibrils. Compared to method B, isolation method A biased the isoform profile of myofibril samples more towards faster MyHC (2A and 2X) in the RST and towards MyHC 2X in the WST. Results suggest that the ATPase activity and MyHC isoform profile of isolated myofibril samples are influenced by method of myofibril isolation, postmortem sampling time, and the rate of postmortem metabolism. Thus, differences in MyHC isoform profile and method of myofibril isolation must be taken into account to determine accurately the relationship between myofibrillar ATPase activity and rate of postmortem metabolism.     

Myosin heavy chain isoforms account for variation in pork quality

The objective of this study was to determine the impact of myosin heavy chain (MyHC) isoforms (I, IIB, IIA and IIX) on pork quality traits of halothane (HAL)-negative (NN) and halothane-carrier (Nn) pigs. Gilts (n=32) were assigned to a 2×2 factorial of genetic population (GP) and slaughter weight (WT; 120 and 135 kg). Classical meat quality characteristics were collected and MyHC content was determined on muscle samples. Regression equations for pork quality and carcass composition traits were determined. Only I/IIB accounted for variation in drip loss of NN gilts (R(2)=0.18), while GP related to drip loss in Nn gilts (R(2)=0.70). Type I MyHC content explained variation in ultimate (24 h) muscle pH of NN gilts (R(2)=0.09), while I/IIB, I/IIX and IIB/IIX were significant for Nn gilts (R(2)=0.99). I/IIA, I/IIX, IIB/IIX and GP accounted for variation in Hunter Color a (redness) values of NN gilts (R(2)=0.69), while IIB, IIA, IIB/IIA and GP were significant for Nn gilts (R(2)=0.97). Overall, fiber type composition accounts for a larger proportion of variation in the quality traits of Nn compared to NN gilts.     

Meta-analysis of the relationship between risk perception and health behavior: The example of vaccination.

Background: Risk perceptions are central to many health behavior theories. However, the relationship between risk perceptions and behavior, muddied by instances of inappropriate assessment and analysis, often looks weak. Method: A meta-analysis of eligible studies assessing the bivariate association between adult vaccination and perceived likelihood, susceptibility, or severity was conducted. Results: Thirty-four studies met inclusion criteria (N = 15,988). Risk likelihood (pooled r = .26), susceptibility (pooled r = .24), and severity (pooled r = .16) significantly predicted vaccination behavior. The risk perception-behavior relationship was larger for studies that were prospective, had higher quality risk measures, or had unskewed risk or behavior measures. Conclusions: The consistent relationships between risk perceptions and behavior, larger than suggested by prior meta-analyses, suggest that risk perceptions are rightly placed as core concepts in theories of health behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of family and peers in the development of prototypes associated with substance use.

Prior research and theory suggest that adolescents often experiment with substances to acquire desired social images. However, little research has addressed the developmental precursors leading to favorable evaluation of substance users. This study tested a model of parental and peer influence on adolescent prototypes using a longitudinal data set of 463 rural adolescents. For both drinking and smoking, positive prototypes of substance users were best predicted by peer affiliations. Adolescents who affiliated with peers who practiced and encouraged substance use developed more positive prototypes of people who drink and smoke. These social images, in turn, predicted subsequent use of alcohol and cigarettes. In contrast to peers, parents had little direct influence on prototypes but did indirectly affect images through the adolescents' choice of peers. Unexpectedly, there was evidence of a negative modeling effect of parental substance use, such that parental smoking predicted more negative prototypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of comb-type copolymers to sustain the surface bactericidal effect of highly water-soluble cationic biocides

Summaries  A series of free radical comb-type acrylic copolymers was prepared in a solution incorporating charged and/or neutral stabilising species on the backbone. The polymer solutions were formulated with cationic biocides to give physically stable formulations with a long shelf life. Furthermore, through the control of polymer architecture of both the side-chain and the backbone, hydrophobicity, a controlled release of a biocide could be achieved. This technology has resulted in the design of temporary coatings demonstrating a sustained surface disinfecting effect. In laboratory trials, coated surfaces with polymeric/biocidal formulations continued to show a disinfection effect after several washes.

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Kammartige Kopolymere helfen, die antibakterielle Wirkung von stark wasserl?slichen kationischen Bioziden an der Oberfl?che zu erhalten

Zusammenfassung  Eine Serie von kammartigen, frei-radikalen Akryl-Kopolymeren wurde in einer L?sung mit geladenen und/oder neutralen Stabilisatoren im Rückgrat hergestellt. Die Polymerl?sungen wurden mit kationischen Bioziden hergestellt, die sie lange haltbar machten. Die Hydrophobit?t sowohl des Polymer-Rückgrades als auch der Nebenketten wurde genau kontolliert, damit das Biozid zielgerecht freigesetzt werden konnte. Diese Technologie hat es uns erlaubt, den Testanstrichen eine nachhaltige Oberfl?chendisinfektionswirkung zu verleihen. Laborversuche zeigten da? die antimikrobielle Wirkung trotz mehrerer Waschvorg?nge verblieb.

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L’usage des copolymères en peigne pour préserver les effets bactéricides surfaciques des biocides cationiques très hydrosolubles

Résumé  Une série de copolymères acryliques en peigne à radical libre a été préparée dans une solution qui incorporait sur la cha?ne principale des espèces stabilisantes chargées et/ou neutres. Les solutions polymériques étaient formulées en utilisant des biocides cationiques pour donner des formulations qui étaient physiquement stables et qui jouissaient d’une longue durée de conservation avant vente. D’ailleurs, grace au contr?le de l’architecture polymérique et de la cha?ne latérale et de la cha?ne principale on pouvait atteindre l’hydrophobicité, une libération contr?lée d’un biocide. Cette technologie a abouti à la conception de revêtements temporaires qui font preuve d’un effet soutenu en ce qui concerne la désinfection de surfaces. Au cours des essais de laboratoire, des surfaces revêtues de formulations polymériques/biocides ont continué à faire preuve d’un effet désinfectant même après plusieurs lavages.

     

Self-esteem and the relation between risk behavior and perceptions of vulnerability to unplanned pregnancy in college women.

This article reports 2 studies testing the hypothesis that individuals with high self-esteem are more likely than those with low self-esteem to interpret information about their personal vulnerability to health risks in a self-serving manner. Study 1 used an experimental paradigm to demonstrate that self-esteem moderates the influence of review of sexual and contraceptive behavior on college women's perceptions of vulnerability to unplanned pregnancy (N?=?125). Study 2 used a longitudinal design to demonstrate that self-esteem also moderates the relation between naturally occurring changes in college women's sexual behavior and changes in their risk perception (N?=?273). Together, these studies provide evidence that people with high self-esteem use self-serving cognitive strategies to maintain their risk perceptions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability of the insecticide cypermethrin during tomato processing and implications for endocrine activity

The thermal and pH stabilities of cypermethrin during food processing were investigated using tomato as a model food system and high-performance liquid chromatography as the analytical method. Cypermethrin was thermally unstable in aqueous conditions, where the hydrolysis of the pesticide was accelerated by heat. The mean proportion remaining after heating cypermethrin in water for 10 min was 66%, falling to 27% after 1 h. Similarly, thermal processing of canned tomatoes caused cypermethrin to degrade, with remaining levels in the final product ranging from 30 to 60% of the original. Cypermethrin was unstable at extreme pHs, with acid hydrolysis occurring faster than alkaline hydrolysis in phosphate buffers. The acidity of tomato paste (pH 4.3) caused cypermethrin levels to decrease by 30% within 12 days at 5°C. The studies indicate that cypermethrin residues are likely to degrade by hydrolysis during food processing, thus reducing the exposure of consumers to cypermethrin. 3-Phenoxybenzaldehyde, a hydrolysis breakdown product of cypermethrin, was detected in the tomato paste and from the heating of cypermethrin in water at 100°C. There is concern that the risk of breakdown products in terms of endocrine activity is unknown since in vitro studies reported that cypermethrin breakdown products display endocrine activity.