Exploring Customers’ Preferences for Online Games

Online content providers who use the Internet to distribute content experience an extremely competitive business environment. To survive in this environment, they have started charging a fee for the content that they provide. However, there have been very few success stories in commercializing online content. Although one of few success stories is the online game, it still has customers’ psychological resistance against paying a high fee for playing games. To pay back their high R&D or development costs quickly, many online game producers have a tendency to assign high prices to their online games. Without examining customers’ perceived prices for online games, many online game producers have tended to decide prices from their perspectives. Although many online game-related research works have focused on psychological and technical aspects, very few works have examined online gamers’ preferences carefully. This study aims at exploring online gamers’ preference by measuring their WTP (Willingness To Pay) for online games

Evaluation of reference genes in mouse preimplantation embryos for gene expression studies using real-time quantitative RT-PCR (RT-qPCR)

BACKGROUND: Real-time quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) is the most sensitive, and valuable technique for rare mRNA detection. However, the expression profiles of reference genes under different experimental conditions, such as different mouse strains, developmental stage, and culture conditions have been poorly studied. RESULTS: mRNA stability of the actb, gapdh, sdha, ablim, ywhaz, sptbn, h2afz, tgfb1, 18 s and wrnip genes was analyzed. Using the NormFinder program, the most stable genes are as follows: h2afz for the B6D2F-1 and C57BL/6 strains; sptbn for ICR; h2afz for KOSOM and CZB cultures of B6D2F-1 and C57BL/6 strain-derived embryos; wrnip for M16 culture of B6D2F-1 and C57BL/6 strain-derived embryos; ywhaz, tgfb1, 18 s, 18 s, ywhaz, and h2afz for zygote, 2-cell, 4-cell, 8-cell, molular, and blastocyst embryonic stages cultured in KSOM medium, respectively; h2afz, wrnip, wrnip, h2afz, ywhaz, and ablim for zygote, 2-cell, 4-cell, 8-cell, molular, and blastocyst stage embryos cultured in CZB medium, respectively; 18 s, h2afz, h2afz, actb, h2afz, and wrnip for zygote, 2-cell, 4-cell, 8-cell, molular, and blastocyst stage embryos cultured in M16 medium, respectively. CONCLUSIONS: These results demonstrated that candidate reference genes for normalization of target gene expression using RT-qPCR should be selected according to mouse strains, developmental stage, and culture conditions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1756-0500-7-675) contains supplementary material, which is available to authorized users

Tidal Effects on Intermediate Waters: A Case Study in the East/Japan Sea

Although tides are believed to be the most important source for diapycnal mixing in the ocean, few studies have directly simulated open-ocean circulation including tides. Because the East/Japan Sea (EJS) has been considered to be a “miniature ocean,” tidal effects on the intermediate water of the EJS are investigated by using an eddy-resolving ocean general circulation model that can take account of M2 and K1 tides as well as oceanic flows. The simulated temperature and salinity in the intermediate layer are significantly improved by including tides. The improvement results from the combined effect of two internal tides. The M2 internal tide, propagating into the interior of the EJS, enhances vertical mixing and brings watermass characteristics closer to those observed. The K1 internal tide, trapped along the coast, induces southwestward flow along the Russian coast in the upper layer and thereby enhances the so-called Liman Current, which transports fresh waters with density conducive to the ventilation of intermediate waters in the EJS

Salinomycin enhances doxorubicin-induced cytotoxicity in multidrug resistant MCF-7/MDR human breast cancer cells via decreased efflux of doxorubicin

Salinomycin is a monocarboxylic polyether antibiotic, which is widely used as an anticoccidial agent. The anticancer property of salinomycin has been recognized and is based on its ability to induce apoptosis in human multidrug resistance (MDR). The present study investigated whether salinomycin reverses MDR towards chemotherapeutic agents in doxorubicin-resistant MCF-7/MDR human breast cancer cells. The results demonstrated that doxorubicin-mediated cytotoxicity was significantly enhanced by salinomycin in the MCF-7/MDR cells, and this occurred in a dose-dependent manner. This finding was consistent with subsequent observations made under a confocal microscope, in which the doxorubicin fluorescence signals of the salinomycin-treated cells were higher compared with the cells treated with doxorubicin alone. In addition, flow cytometric analysis revealed that salinomycin significantly increased the net cellular uptake and decreased the efflux of doxorubicin. The expression levels of MDR-1 and MRP-1 were not altered at either the mRNA or protein levels in the cells treated with salinomycin. These results indicated that salinomycin was mediated by its ability to increase the uptake and decrease the efflux of doxorubicin in MCF-7/MDR cells. Salinomycin reversed the resistance of doxorubicin, suggesting that chemotherapy in combination with salinomycin may benefit MDR cancer therapyopen

Effect of analgesia nociception index monitor-based nociception control on perioperative stress responses during laparoscopic surgery in Trendelenburg position: a randomized controlled trial

IntroductionThe analgesia nociception index (ANI) monitor is a nociception monitoring device based on heart rate variability. We aimed to determine the effect of ANI monitor-based intraoperative nociception control on the perioperative stress response during laparoscopic surgery in the Trendelenburg position.MethodsAltogether, 72 female patients who underwent total laparoscopic hysterectomy were randomized to either the control or ANI group. Intraoperative nociception was controlled by remifentanil administration in a conventional manner (based on blood pressure and heart rate) in the control group and by ANI monitoring in the ANI group. Perioperative stress responses were estimated by measuring the levels of serum catecholamines and catabolic stress hormones at three timepoints: after loss of consciousness, at the end of surgery, and 1 h after the end of surgery.ResultsThe serum cortisol level at the end of surgery was significantly higher in the ANI group than in the control group (p < 0.001), although more remifentanil was administered in the ANI group than in the control group (p < 0.001). Changes in the other estimators’ levels were comparable between groups during the perioperative period. The hemodynamic profiles during surgery were also significantly different between the two groups. Phenylephrine use to treat hypotension was more common in the ANI group than in the control group (p = 0.005). However, postoperative clinical outcomes such as pain and nausea/vomiting did not differ between groups.ConclusionANI monitor-based nociception control in laparoscopic surgery in the Trendelenburg position did not improve perioperative stress responses, intraoperative opioid consumption, or postoperative clinical outcomes.Clinical trial registration:ClinicalTrials.gov (NCT04343638)

Association Between Impairment of DNA Double Strand Break Repair and Decreased Ovarian Reserve in Patients With Endometriosis

Background: Repair of DNA double strand break (DSB) is an important mechanism for maintaining genetic stability during a DNA damage event. Although, a growing body of recent evidence suggests that DNA DSBs and related repair mechanisms may be important in ovarian aging and in various cancers, there are few reports in endometriosis. We, therefore, examined expression levels of genes pertaining to DNA DSB repair in patients with endometriosis to assess the potential effects on ovarian reserves.Materials and methods: A total of 69 women undergoing laparoscopic surgery for endometriosis and other benign conditions was included; endometriosis group (n = 38) vs. controls (n = 31). DNA DSBs in endometrial and ovarian tissues of both groups were compared via immunohistochemistry, aimed at γ-H2AX expression. To gauge genotoxin-induced DNA DSBs in endometrial stromal cells, γ-H2AX expression was determined by western blot after H2O2 treatment of cultured endometrial stromal cells (endometriosis group and controls) and Ishikawa cell-line cultures. Endometrial and ovarian tissue levels of BRCA1, BRCA2, Rad51, and ATM (ataxia-telangiectasia mutated) mRNA expression were also compared. Correlations between expression levels of genes of interest and serum anti-müllerian hormone (AMH) levels were assessed as well.Results: Expression of γ-H2AX in immunostained endometrial and ovarian tissue preparations was greater in the endometriosis group, compared with controls. After H2O2 treatment, γ-H2AX expression levels were also significantly greater in cultured stromal cells of the endometriosis group and in the Ishikawa cell line than in controls. Endometrial expression of BRCA1 and Rad51 mRNA proved significantly lower in the endometriosis group (vs. controls), as did ovarian expression of BRCA1 and BRCA2 mRNA. Serum AMH concentration showed a significant correlation with ovarian BRCA1 mRNA expression in women with endometriosis (p = 0.03).Conclusions: In women with endometriosis, expression levels of various genes implicated in DSB repair are decreased and ovarian BRCA1 expression correlates wit

Genetic Traceability of Black Pig Meats Using Microsatellite Markers

Pork from Jeju black pig (population J) and Berkshire (population B) has a unique market share in Korea because of their high meat quality. Due to the high demand of this pork, traceability of the pork to its origin is becoming an important part of the consumer demand. To examine the feasibility of such a system, we aim to provide basic genetic information of the two black pig populations and assess the possibility of genetically distinguishing between the two breeds. Muscle samples were collected from slaughter houses in Jeju Island and Namwon, Chonbuk province, Korea, for populations J and B, respectively. In total 800 Jeju black pigs and 351 Berkshires were genotyped at thirteen microsatellite (MS) markers. Analyses on the genetic diversity of the two populations were carried out in the programs MS toolkit and FSTAT. The population structure of the two breeds was determined by a Bayesian clustering method implemented in structure and by a phylogenetic analysis in Phylip. Population J exhibited higher mean number of alleles, expected heterozygosity and observed heterozygosity value, and polymorphism information content, compared to population B. The FIS values of population J and population B were 0.03 and −0.005, respectively, indicating that little or no inbreeding has occurred. In addition, genetic structure analysis revealed the possibility of gene flow from population B to population J. The expected probability of identify value of the 13 MS markers was 9.87×10−14 in population J, 3.17×10−9 in population B, and 1.03×10−12 in the two populations. The results of this study are useful in distinguishing between the two black pig breeds and can be used as a foundation for further development of DNA markers

Exploring evidence of positive selection reveals genetic basis of meat quality traits in Berkshire pigs through whole genome sequencing

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Natural and artificial selection following domestication has led to the existence of more than a hundred pig breeds, as well as incredible variation in phenotypic traits. Berkshire pigs are regarded as having superior meat quality compared to other breeds. As the meat production industry seeks selective breeding approaches to improve profitable traits such as meat quality, information about genetic determinants of these traits is in high demand. However, most of the studies have been performed using trained sensory panel analysis without investigating the underlying genetic factors. Here we investigate the relationship between genomic composition and this phenotypic trait by scanning for signatures of positive selection in whole-genome sequencing data. Results We generated genomes of 10 Berkshire pigs at a total of 100.6 coverage depth, using the Illumina Hiseq2000 platform. Along with the genomes of 11 Landrace and 13 Yorkshire pigs, we identified genomic variants of 18.9 million SNVs and 3.4 million Indels in the mapped regions. We identified several associated genes related to lipid metabolism, intramuscular fatty acid deposition, and muscle fiber type which attribute to pork quality (TG, FABP1, AKIRIN2, GLP2R, TGFBR3, JPH3, ICAM2, and ERN1) by applying between population statistical tests (XP-EHH and XP-CLR). A statistical enrichment test was also conducted to detect breed specific genetic variation. In addition, de novo short sequence read assembly strategy identified several candidate genes (SLC25A14, IGF1, PI4KA, CACNA1A) as also contributing to lipid metabolism. Conclusions Results revealed several candidate genes involved in Berkshire meat quality; most of these genes are involved in lipid metabolism and intramuscular fat deposition. These results can provide a basis for future research on the genomic characteristics of Berkshire pigs

Characteristics of pediatric rhabdomyolysis and the associated risk factors for acute kidney injury: a retrospective multicenter study in Korea

Background The clinical features of pediatric rhabdomyolysis differ from those of the adults with rhabdomyolysis; however, multicenter studies are lacking. This study aimed to investigate the characteristics of pediatric rhabdomyolysis and reveal the risk factors for acute kidney injury (AKI) in such cases. Methods This retrospective study analyzed the medical records of children and adolescents diagnosed with rhabdomyolysis at 23 hospitals in South Korea between January 2007 and December 2016. Results Among 880 patients, those aged 3 to 5 years old composed the largest subgroup (19.4%), and all age subgroups were predominantly male. The incidence of AKI was 11.3%. Neurological disorders (53.6%) and infection (39.0%) were the most common underlying disorder and cause of rhabdomyolysis, respectively. The median age at diagnosis in the AKI subgroup was older than that in the non-AKI subgroup (12.2 years vs. 8.0 years). There were no significant differences in body mass index, myalgia, dark-colored urine, or the number of causal factors between the two AKI-status subgroups. The multivariate logistic regression model indicated that the following factors were independently associated with AKI: multiorgan failure, presence of an underlying disorder, strong positive urine occult blood, increased aspartate aminotransferase and uric acid levels, and reduced calcium levels. Conclusions Our study revealed characteristic clinical and laboratory features of rhabdomyolysis in a Korean pediatric population and highlighted the risk factors for AKI in these cases. Our findings will contribute to a greater understanding of pediatric rhabdomyolysis and may enable early intervention against rhabdomyolysis-induced AKI

Space Target Classification Improvement by Generating Micro-Doppler Signatures Considering Incident Angle

Classifying space targets from debris is critical for radar resource management as well as rapid response during the mid-course phase of space target flight. Due to advances in deep learning techniques, various approaches have been studied to classify space targets by using micro-Doppler signatures. Previous studies have only used micro-Doppler signatures such as spectrogram and cadence velocity diagram (CVD), but in this paper, we propose a method to generate micro-Doppler signatures taking into account the relative incident angle that a radar can obtain during the target tracking process. The AlexNet and ResNet-18 networks, which are representative convolutional neural network architectures, are transfer-learned using two types of datasets constructed using the proposed and conventional signatures to classify six classes of space targets and a debris–cone, rounded cone, cone with empennages, cylinder, curved plate, and square plate. Among the proposed signatures, the spectrogram had lower classification accuracy than the conventional spectrogram, but the classification accuracy increased from 88.97% to 92.11% for CVD. Furthermore, when recalculated not with six classes but simply with only two classes of precessing space targets and tumbling debris, the proposed spectrogram and CVD show the classification accuracy of over 99.82% for both AlexNet and ResNet-18. Specially, for two classes, CVD provided results with higher accuracy than the spectrogram