Properties of the Molecular Cores of Low Luminosity Objects

We present a survey toward 16 Low Luminosity Objects (LLOs with an internal luminosity, Lint, lower than 0.2 Lsun) with N2H+ (1-0), N2H+ (3-2), N2D+ (3-2), HCO+ (3-2) and HCN (3-2) using the Arizona Radio Observatory Kitt Peak 12m Telescope and Submillimeter Telescope. Our goal is to probe the nature of these faint protostars which are believed to be either very low mass or extremely young protostars. We find that the N2D+/N2H+ column density ratios of LLOs are similar to those of typical starless cores and Class 0 objects. The N2D+/N2H+ column density ratios are relatively high (> 0.05) for LLOs with kinetic temperatures less than 10 K in our sample. The distribution of N2H+ (1-0) line widths spreads between that of starless cores and young Class 0 objects. If we use the line width as a dynamic evolutionary indicator, LLOs are likely young Class 0 protostellar sources. We further use the optically thick tracers, HCO+ (3-2) and HCN (3-2), to probe the infall signatures of our targets. We derive the asymmetry parameters from both lines and estimate the infall velocities by fitting the HCO+ (3-2) spectra with two-layer models. As a result, we identify eight infall candidates based on the infall velocities and seven candidates have infall signatures supported by asymmetry parameters from at least one of HCO+ (3-2) and HCN (3-2).Comment: 15 pages, 8 figures, accepted to Ap

Understanding the Intention of Giving Information in Virtual Communities

The major activity in a virtual community is information exchange among members. However, even in busy virtual communities, usually only a small fraction of members post information actively. Our interest in this study was seeking a better understanding of the psychological determinants that drive people to give information actively and voluntarily. An empirical study was conducted and 273 responses that have experiences in virtual communities were collected. The research model was mainly evaluated and validated with Structural Equation Modeling (SEM)-LISREL. The results suggest that members’ perceived self-efficacy, perceived soft rewards, trust to other members, social identity, and positive anticipated emotions have positively effects on intention of giving information through the mediation of desire

Use of dietary supplements by breast cancer patients undergoing conventional cancer treatment

<b>Background</b> Many breast cancer patients use some form of dietary supplement (DS) to complement their conventional cancer treatment, in the hope that they might lessen the side effects of treatment, improve quality of life, give a greater sense of control, and reduce stress. This pilot study assessed the level of DS usage by breast cancer patients undergoing conventional cancer treatment, and their concerns about the use of DS. <p></p> <b>Method</b> A cross-sectional descriptive survey in three breast cancer centers in Hong Kong using face-to-face interviewing was performed. <p></p> <b>Results</b> Of 82 female Chinese breast cancer patients who completed the survey, 99% reported that they had been using DS since their cancer was diagnosed. The most frequently used DS were Chinese herbal medicines, and patients spent about US$258 on DS every month. The reason given for using DS was to enhance their recovery from cancer, but at the same time the patients had safety concerns. However, most patients did not feel able to discuss these concerns with health professionals. <p></p> <b>Conclusion</b> The majority of the patients had some safety concerns, and said that they would welcome detailed and reliable information on DS. The lack of reliable information on the potential risks and benefits of using such supplements as an adjuvant to conventional treatment and the reluctance of patients to discuss their use of DS with health professionals is a major area of concern that warrants further attention

Production of a diacylglycerol-enriched palm olein using lipase-catalyzed partial hydrolysis : optimization using response surface methodology

Partial hydrolysis using Lipozyme RMIM lipase in a solvent-free system was used to produce a diacylglycerol (DAG)-enriched palm olein. Response surface methodology (RSM) was applied to model and optimize the reaction conditions namely water content (30– 70 wt% of enzyme mass), enzyme load (5–15 wt% of oil mass), reaction temperature (45–85 C) and reaction time (6–16 h). Well fitting models were successfully established for both DAG yield (R2 = 0.8788) and unhydrolysed triacylglycerol (TAG) (R2 = 0.8653) through multiple linear regressions with backward elimination. Chi-square test indicated that there were no significant (P > 0.05) differences between the observed and predicted values for both models. All reaction conditions had positive effects on DAG yield and negative effects on unhydrolysed TAG. Optimal reaction conditions were: 50 wt% water content, 10 wt% enzyme load, 65C of reaction temperature and 12 h of reaction time. The process was further up-scaled to a 9 kg production in a continuous packed bed bioreactor. Results indicated that upscaling was possible with a similar DAG yield (32 wt%) as in lab scale. Purification of the DAG oil using short path distillation yielded a DAG-enriched palm olein with 60 wt% DAG and 40 wt% TAG which is suitable for margarine, spread or shortening applications

The Evolution of Density Structure of Starless and Protostellar Cores

We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless to Class I. Our results show that the density structure of all but one observed cores can be modeled with a single power law rho \propto r^p between ~ 0.2R-R of the cores. The starless cores in our sample show two different types of density structures, one follows p ~ -1.0 and the other follows p ~ -2.5, while the protostellar cores all have p ~ -2.5. The similarity between the prestellar cores with p ~ -2.5 and protostellar cores implies that those prestellar cores could be evolving towards the protostellar stage. The slope of p ~ -2.5 is steeper than that of an singular isothermal sphere, which may be interpreted with the evolutionary model of cores with finite mass.Comment: 19 pages, 3 figures, accepted for publication in the Astrophysical Journa

Anti–hypercholesterolemic effect of kenaf (Hibiscus cannabinus L.) seed on high–fat diet Sprague dawley rats

AbstractObjectiveTo determine the antihypercholesterolemic effects of kenaf seed samples and compare with the commercial hypocholesterolemic drug on serum lipids profiles and malondialdehyde (MDA) level in the rat.MethodsKenaf seed oil (KSO), microencapsulated kenaf seed oil (MKSO), kenaf seed extract (KSE) and defatted kenaf seed meal (DKSM) were prepared and phytochemicals screening on these samples were done prior in vivo study. Phenolic compounds in KSE were quantified using high performance liquid chromatography. There were 40 (divided in eight diet groups of 5) male Sprague dawley rats adapted to normal standard diet or hypercholesterolemic diet (HD) with or without the treatment of these kenaf samples for 32 days.ResultsAll the kenaf samples exhibited to contain most of the major phytochemicals. KSE possessed gallic acid, tannic acid, catechin, benzaldehyde, benzoic acid, syringic acid, sinapic acid, ferulic acid, naringin acid, and protocatechuic acid. The significant higher (P<0.05) serum total cholesterol, low density lipoprotein cholesterol and MDA levels in HD group without treatment than the normal control group suggested the hypercholesterolemia was induced by the incorporation of cholesterol into diet. KSE exhibited higher cholesterol–lowering properties due to the significant lower (P<0.05) in serum triglycerides, total cholesterol and MDA levels. KSE showed the highest efficiency of cholesterol–lowering activity, followed by KSO, MKSO and DKSM.ConclusionsDKSM, MKSO, KSO and KSE appeared to have comparable anti–hypercholesterolemic effect with the commercial hypocholesterolemic drug. Hence, kenaf seed could be used as an alternative natural source to replace the synthetic hypocholesterolemic drugs