INVESTGATING THE INTENTION OF PURCHASING DIGITAL ITEMS IN VIRTUAL COMMUNITIES

Most virtual community (VC) providers lack profitable business models. The challenge for VC providers is to generate and increase revenue from sources other than advertising. The sale of digital items (e.g., avatar) to VC members is a recent revenue generation method. This study examines how VC members decide to purchase digital items from the customer value perspective. Based on customer value theory, this study identifies six factors over three dimensions of customer value and examines their effects on VC members’ intention of purchasing digital items. Our finding suggests that the effect of value on members’ purchase intentions is significant in the functional (i.e., quality of digital items), social (i.e., social self-image), and emotional (i.e., playfulness) value dimensions. This study provides important implications for practitioners to understand how they can foster an ideal environment for customers to perceive more value in their digital items so that it would be more compelling to make purchases in a VC

Topological Structure of Dense Hadronic Matter

We present a summary of work done on dense hadronic matter, based on the Skyrme model, which provides a unified approach to high density, valid in the large $N_c$ limit. In our picture, dense hadronic matter is described by the {\em classical} soliton configuration with minimum energy for the given baryon number density. By incorporating the meson fluctuations on such ground state we obtain an effective Lagrangian for meson dynamics in a dense medium. Our starting point has been the Skyrme model defined in terms of pions, thereafter we have extended and improved the model by incorporating other degrees of freedom such as dilaton, kaons and vector mesons.Comment: 13 pages, 8 figures, Talk given at the KIAS-APCTP Symposium in Astro-Hadron Physics "Compact Stars: Quest for New States of Dense Matter", November 10-14, 2003, Seoul, Korea, published by World Scientific. Based on talk by B.-Y. Par

17β-estradiol reduces inflammation and modulates antioxidant enzymes in colonic epithelial cells

Background/Aims: Estrogen is known to have protective effect in colorectal cancer development. The aims of this study are to investigate whether estradiol treatment reduces inflammation in CCD841CoN, a female human colonic epithelial cell line and to uncover underlying mechanisms of estradiol effects. Methods: 17 beta-Estradiol (E2) effect was measured by Western blot after inducing inflammation of CCD841CoN by tumor necrosis factor alpha (TNF-alpha). Expression levels of estrogen receptor alpha (ER alpha) and beta (ER beta), cyclooxygenase-2 (COX-2), nuclear factor-kappa B (NF-kappa B), heme oxygenase-1 (HO-1), and NAD(P)H-quinone oxidoreductase-1 (NQO-1) were also evaluated. Results: E2 treatment induced expression of ERO but did not increase that of ER alpha. E2 treatment for 48 hours significantly elevated the expression of anti-oxidant enzymes, HO-1 and NQO-1. TNF-alpha treatment significantly increased the level of activated NF-kappa B (p < 0.05), and this increase was significantly suppressed by treatment of to nM of E2 (p < 0.05). E2 treatment ameliorated TNF-alpha-induced COX-2 expression and decrease of HO-1 expression. 4-(2-phenyl-5,7-bis(trifluoromethyl) pyrazolo(1,5-a)pyrimidin-3-yl)phenol (PHTPP), antagonist of ER beta, removed the inhibitory effect of E2 in the TNF-alpha-induced COX-2 expression (p = 0.05). Conclusions: Estrogen seems to inhibit inflammation in female human colonic epithelial cell lines, through down-regulation of NF-kappa B and COX-2 expression and induction of anti-oxidant enzymes such as HO-1 and NQO-1.

Nuclear transfer in ruminants

Ruminants were the first mammalian species to be cloned successfully by nuclear transplantation. Those experiments were designed to multiply high merit animals (Willadsen, Nature 320(6057):63–65, 1986; Prather et al., Biol Reprod 37(4):859–866, 1987; Wilmut et al., Nature 385(6619):810–813, 1997). Since then, cloning has provided us with a vast amount of knowledge and information on the reprogramming ability of somatic cells to different cell types which became an important basis for stem cell research and human medicine. Nowadays, the goals of most nuclear transfer work vary widely but in most cases the micromanipulation procedures remain the same. However, differences between species require different technical considerations. In this chapter, we describe in detail somatic cell nuclear transfer which is the foremost method for cloning ruminants with specific reference to sheep and cattle

Molecular cloning and expression of a novel human cDNA related to the diazepam binding inhibitor

AbstractIn order to isolate the unidentified autoantigens in autoimmune diabetes, a human pancreatic islet cDNA library was constructed and screened with the sera from the diabetic patients. From the library screening, one clone (DRS-1) that strongly reacted with the sera was isolated. Subsequent sequence analysis revealed that the clone was a novel cDNA related to the diazepam binding inhibitor. DRS-1 was expressed in most tissues including liver, lung, tonsil, and thymus, in addition to pancreatic islets. DRS-1 was in vitro translated and the recombinant DRS-1 protein was expressed in Escherichia coli and purified. The size of the in vitro translated or bacterially expressed DRS-1 protein was in agreement with the conceptually translated polypeptide of DRS-1 cDNA. Further studies are required to test whether or not DRS-1 is a new autoantigen in autoimmune diabetes

17β-Estradiol supplementation changes gut microbiota diversity in intact and colorectal cancer-induced ICR male mice

The composition of the gut microbiota is influenced by sex hormones and colorectal cancer (CRC). Previously, we reported that 17 beta -estradiol (E2) inhibits azoxymethane/dextran sulfate sodium (AOM/DSS)-induced tumorigenesis in male mice. Here, we investigated whether the composition of the gut microbiota is different between male and female, and is regulated by estrogen as a secondary outcome of previous studies. We established four groups of mice based on the sex and estrogen status [ovariectomized (OVX) female and E2-treated male]. Additionally, three groups of males were established by treating them with AOM/DSS, and E2, after subjecting them to AOM/DSS treatment. The mice were sacrificed at 21 weeks old. The composition of the gut microbiota was analyzed using 16S rRNA metagenomics sequencing. We observed a significant increase in the microbial diversity (Chao1 index) in females, males supplemented with E2, and males treated with AOM/DSS/E2 compared with normal males. In normal physiological condition, sex difference and E2 treatment did not affect the ratio of Firmicutes/Bacteroidetes (F/B). However, in AOM/DSS-treated male mice, E2 supplementation showed significantly lower level of the F/B ratio. The ratio of commensal bacteria to opportunistic pathogens was higher in females and E2-treated males compared to normal males and females subjected to OVX. Unexpectedly, this ratio was higher in the AOM/DSS group than that determined in other males and the AOM/DSS/E2 group. Our findings suggest that estrogen alters the gut microbiota in ICR (CrljOri:CD1) mice, particularly AOM/DSS-treated males, by decreasing the F/B ratio and changing Shannon and Simpson index by supply of estrogen. This highlights another possibility that estrogen could cause changes in the gut microbiota, thereby reducing the risk of developing CRC.

Actin depolymerization is associated with meiotic acceleration in cycloheximide-treated ovine oocytes

Oocytes treated with the protein synthesis inhibitor cycloheximide (CHX) arrest at the germinal vesicle (GV) stage and undergo accelerated GV breakdown (GVBD) after CHX is removed. However, little is known about the underlying mechanism of accelerated meiotic maturation. Here, we investigated this mechanism and found that oocytes released from CHX arrest have higher amounts of cyclin B1 (CCNB1) and phosphorylated mitogen-activated protein kinase (pMAPK) proteins. Increased levels of these factors were not associated with mRNA polyadenylation or increased transcription rates of CCNB1 and MOS (Moloney murine sarcoma viral oncogene homolog) during CHX arrest. We found that treatment of CHX-arrested oocytes with the actin filament-stabilizing agent Jasplakinolide (Jasp) delayed GVBD following release from CHX arrest and that this was correlated with reduced maturation-promoting factor (MPF) activity. These results suggest that CCNB1 mRNAs released from actin filaments during CHX arrest increase CCNB1 transcripts available for translation after release from CHX arrest, leading to the precocious activation of MPF and accelerated meiotic progression

2D perovskite stabilized phase-pure formamidinium perovskite solar cells.

Compositional engineering has been used to overcome difficulties in fabricating high-quality phase-pure formamidinium perovskite films together with its ambient instability. However, this comes alongside an undesirable increase in bandgap that sacrifices the device photocurrent. Here we report the fabrication of phase-pure formamidinium-lead tri-iodide perovskite films with excellent optoelectronic quality and stability. Incorporation of 1.67 mol% of 2D phenylethylammonium lead iodide into the precursor solution enables the formation of phase-pure formamidinium perovskite with an order of magnitude enhanced photoluminescence lifetime. The 2D perovskite spontaneously forms at grain boundaries to protect the formamidinium perovskite from moisture and suppress ion migration. A stabilized power conversion efficiency (PCE) of 20.64% (certified stabilized PCE of 19.77%) is achieved with a short-circuit current density exceeding 24 mA cm-2 and an open-circuit voltage of 1.130 V, corresponding to a loss-in-potential of 0.35 V, and significantly enhanced operational stability