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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.chb.2010.06.003 Byline: Gyudong Lee, Won Jun Lee Keywords: Helping in organizations; Knowledge management; Knowledge sharing; Information providing Abstract: Helping is more likely to occur when potential helpers can clearly understand the help-seeker's needs and when they can freely choose whether to help or not. Information systems such as electronic bulletin boards, web communities, and knowledge management systems all satisfy these conditions. In order to explain helping behaviors in the workplace, we employ the personality traits of altruism and job autonomy, as well as the characteristics of the information systems used by employees in organizations. In this study, we conducted a survey of business persons who use information systems in the workplace. The results of our study indicate that altruism and job autonomy have both the main and interaction effects on the willingness to help others through information systems. With regard to the effects of the characteristics of information systems, the media richness of information systems exerts a positive impact on willingness to help. On the contrary, the size of the user group affects the willingness to help negatively, which reflects the bystander effect in the offline world. Implications for both researchers and practitioners are discussed. Author Affiliation: SKKU Business School, Sungkyunkwan University, Seoul, South Korea

Nanocomposites are critically influenced by interfacial interactions between the reinforcement and matrix. Polyvinyl alcohol (PVOH) of varying molecular weights were prepared and grafted-to single-walled carbon nanotubes (SWCNTs), to improve the interfacial interaction with a homopolymer PVOH matrix. Nanocomposite fibers were coagulation spun across a broad range of loading fractions, controlled by the spinning dope composition. An intermediate grafted-PVOH molecular weight (10 kDa) maximized grafting ratio, and the final composite mechanical performance; the positive effects were attributed to the increased degree of dispersion of the SWCNTs in the dope, as well as the favorable interface. The PVOH grafting increased the stability of the SWCNT loading fractions (up to 45 wt.%), offering increased strength (up to 1100 MPa) and stiffness (up to 38.5 GPa); at the same time, strain-to-failures remained high (up to 23.3%), resulting in high toughness (up to 125 J g−1). Image 1 [ABSTRACT FROM AUTHOR]

Due to limitations of estrogen replacement therapy, life style interventions have received a growing attention. This study aimed to determine whether Pueraria-Rehmannia (PR) and/or aerobic exercise (Ex) could reduce cardiometabolic dysfunction in an ovariectomized/high-fat diet rat model. PR ameliorated circulating levels of total cholesterol, LDL/HDL ratio, and leptin. It reduced fat mass, fat size, leptin gene expression, and macrophage infiltration in adipocytes. PR maintained leptin receptor gene expression in muscle tissues. It stimulated insulin-mediated GLUT4 translocation in muscle and adipose tissues. PR plus Ex resulted in further improvement in glucose homeostasis by stimulating Akt-mediated insulin receptor expression in the liver. Moreover, PR and/or Ex reduced vascular wall thickness and intracellular cell adhesion molecule-1 production without causing uterotrophic effect. These results suggest that PR and Ex may exert synergistic effects in modifying metabolic dysfunctions and insulin resistance, thus suppressing cardiovascular risks in postmenopausal women through restoring insulin sensitivity and attenuating inflammation. [ABSTRACT FROM AUTHOR]

Studies on the effects of postprocessing conditions on the physical properties, degree of conversion (DC), and biocompatibility of denture bases produced by digital light processing are lacking. The purpose of this in vitro study was to evaluate the effects of the atmosphere during postpolymerization and of postpolymerization time on the flexural strength, Vickers hardness, DC, cytotoxicity, and residual monomer content of denture bases. Six different groups of bar- and disk-shaped specimens from the denture base resin were produced, considering 2 different atmospheres (air and nitrogen) and 3 different postpolymerization times (5, 10, and 20 minutes). To determine the physical properties, the flexural strength and Vickers hardness were measured. Fourier transform infrared spectrometry was used to calculate DC. Cytotoxicity was assessed from the effect on human gingival fibroblasts. The residual monomer content was determined by using high-performance liquid chromatography. Based on the normality test by the Shapiro-Wilk method, a nonparametric factorial analysis of variances was conducted (α=.05). A significant interaction was detected between the atmosphere and postpolymerization time for hardness (P <.001) but no interaction for strength, DC, or cytotoxicity (P =.826, P =.786, and P =.563, respectively). Hardness was significantly affected by the postpolymerization time in the groups with the nitrogen atmosphere (P <.001). DC was significantly affected by the atmosphere (P =.012), whereas strength and cytotoxicity were not (P =.500 and P =.299, respectively). Cytotoxicity was significantly affected by the postpolymerization time (P <.001), but strength and DC were not (P =.482 and P =.167, respectively). Residual monomers were not detected after ≥10-minute postpolymerization time. The atmosphere significantly affected hardness and DC, whereas the postpolymerization time significantly affected hardness, DC, cytotoxicity, and residual monomer content. Denture bases produced in a nitrogen atmosphere and with the 10-minute postpolymerization time showed sufficient hardness, DC, and no cytotoxicity. [ABSTRACT FROM AUTHOR]

A broadband radar absorbing structure (RAS) covering both X and Ku bands (8.2–18.0 GHz) was designed by integrating an inductive frequency-selective carbon fiber fabric composite (FSFC) and multiwalled carbon nanotube (MWCNT)-loaded glass fabrics which can modulate EMI characteristics of the FSFC. All the layers of the structure consisted of fiber-reinforced fabrics, and thus general composite fabrication processes can be easily applied. An existing scaling law based on the percolation theory was modified to replicate permittivity of the MWCNT-loaded fabrics. Coefficients and exponents of the power law were expressed by frequency and MWCNT concentration. The modified model provides a good description of the dielectric property of MWCNT fabric composites, and thus paves the way for parametric evaluation of reflection loss of the FSFC-embedded double-layered RAS regarding the permittivity of the lossy dielectric composites, as well as thickness of each layer and the total thickness of the RAS. The reflection loss of the RAS, drawn from the parametric study, can cover 10 dB in the whole X and Ku bands with two separated absorption peaks, while its thickness was 3.63 mm only. [ABSTRACT FROM AUTHOR]

Purpose The appropriate mode of exercise training for cancer cachexia is not well-established. Using the colon-26 (C26) mouse model of cancer cachexia, we defined and compared the skeletal muscle responses to aerobic and resistance training. Methods Twelve-month old Balb/c mice were initially assigned to control, aerobic training (AT; wheel running), or resistance training (RT; ladder climbing) (n = 16–17/group). After 8 weeks of training, half of each group was injected with C26 tumor cells, followed by 3 additional weeks of training. Body composition and neuromuscular function was evaluated pre- and post-training. Muscles were collected post-training and analyzed for fiber cross-sectional area (CSA), Akt–mTOR signaling, and expression of insulin-like growth factor-I (IGF-I) and myogenic regulatory factors. Results Total body mass decreased (p < 0.05) in C26 (− 8%), AT + C26 (− 18%), and RT + C26 (− 15%) but not control. Sensorimotor function declined (p < 0.05) in control (− 16%), C26 (− 13%), and RT + C26 (− 23%) but not AT + C26. Similarly, strength/body weight decreased (p < 0.05) in control (− 7%), C26 (− 21%), and RT + C26 (− 10%) but not AT + C26. Gastrocnemius mass/body weight tended to be greater in AT + C26 vs. C26 (+ 6%, p = 0.09). Enlargement of the spleen was partially corrected in AT + C26 (− 27% vs. C26, p < 0.05). Fiber CSA was lower in all C26 groups vs. control (− 32% to 46%, p < 0.05); however, the effect size calculated from C26 and AT + C26 was large (+ 24%, d = 1.04). Phosphorylated levels of mTOR in AT + C26 exceeded C26 (+ 32%, p < 0.05). RT + C26 showed greater mRNA expression (p < 0.05) of IGF-IEa (+ 79%) and myogenin (+ 126%) with a strong tendency for greater IGF-IEb (+ 127%, p = 0.069) vs. control. Conclusions Aerobic or resistance training was unable to prevent tumor-induced body weight loss. However, aerobic training may have preserved function, reduced the inflammatory response of the spleen, and marginally rescued muscle mass possibly through activation of mTOR. Aerobic training may therefore have therapeutic value for patients with cancer cachexia. In contrast, resistance training induced the expression of genes associated with muscle damage and repair. This gene response may be supportive of excessive stress generated by high resistance loading in a tumor-bearing state. [ABSTRACT FROM AUTHOR]

The metabolic activities of a given gut bacterium or gut commensal community fluctuate in a manner largely depending on the physicochemical parameters within the gut niche. Recognition of the bacterial metabolic status in situ , by a sensing of the gut metabolites as a signature of a specific bacterial metabolic activity, has been suggested to be a highly beneficial means for the host to maintain gut–microbe homeostasis. Recently, analysis of Drosophila gut immunity revealed that bacterial-derived uracil and uracil-modulated intestinal reactive oxygen species (ROS) generation play a pivotal role in diverse aspects of host–microbe interactions, such as pathogen clearance, commensal protection, intestinal cell regeneration, colitogenesis, and possibly also interorgan immunological communication. A deeper understanding of the role of uracil in Drosophila immunity will provide additional insight into the molecular mechanisms underlying host–microbe symbiosis and dysbiosis. [ABSTRACT FROM AUTHOR]

Periodic patterned surfaces can provide effective dielectric constants to the microwave absorbing honeycomb partition wall depending on the size of the pattern. A characteristic study was conducted for a honeycomb-shaped absorber based on the geometric configurations and material properties. The range of the relative permittivity for increasing the absorption bandwidth of the absorber was determined through a parametric study. The imaginary term of the relative permittivity and depth of the wave propagation direction had a significant impact on the bandwidth of the absorber. Moreover, the materials patterned with carbon black- and graphite-based conductive inks using the screen-printing method were bonded to each other at intervals and stacked to form a honeycomb shape. Several absorber specimens were fabricated, and their absorption capabilities were measured using a free-space measurement system. Based on the results, the utility of a film-based honeycomb absorber that can continuously maintain broadband absorptivity was verified. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To investigate the efficacy and underlying mechanisms of β-hydroxy-β-methylbutyrate (HMB) on body composition, muscle mass and physical performance under catabolic versus normal training conditions. Materials/Methods: Mice were divided into four groups (n=10/group): 1) ALT=ad libitum+trained (1h/d for 3d/wk); 2) ALTH=ALT+HMB (0.5g/kg BW/d); 3) C=calorie restricted (−30%)+trained (6h/d, 6d/wk); and 4) CH=C+HMB. Repeated in vivo assessments included body composition, grip strength and sensorimotor coordination before and after the experimental protocol, while in vitro analyses included muscle wet weights, expression of selected genes and proteins regulating muscle mass, and myofiber cross-sectional area. ANOVAs were used with significance set at p<0.05. Results: ALTH had greater lean mass than ALT and sensorimotor function increased in ALTH, but decreased in ALT under normal training conditions. Grip strength decreased only in C, but was maintained in CH. Gastrocnemius mass and myofiber CSA were greater in CH than C following catabolic conditions. Gastrocnemius atrogin-1 mRNA expression was elevated in C but not in CH compared to all other groups whereas atrogin-1 protein levels showed no significant changes. Conclusion: HMB improves body composition and sensorimotor function during normal training and attenuates muscle mass and strength loss during catabolic conditions. [Copyright &y& Elsevier]