27 research outputs found

    What Should Streamers Communicate in Livestream E-Commerce? The Effects of Social Interactions on Live Streaming Performance

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    Compared with traditional e-commerce, livestreaming e-commerce is characterized by direct and intimate communication between streamers and consumers that stimulates instant social interactions. This study focuses on streamers’ three types of information exchange (i.e., product information, social conversation, and social solicitation) and examines their roles in driving both short-term and long-term livestreaming performance (i.e., sales and customer base growth). We find that the informational role of product information (nonpromotional and promotional) is beneficial not only to sales performance, but also to the growth of the customer base. We also find that social conversation has a relationship-building effect that positively impacts both sales and customer base growth, whereas social solicitation has both a relationship-building and a relationship-straining effect that positively affects customer base growth but can hurt sales. Furthermore, our results show that streamers’ social interactions with consumers can stimulate consumer engagement in different ways, leading to different effects on livestreaming performance

    Mutations in TUBB8 and Human Oocyte Meiotic Arrest

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    BACKGROUND Human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. METHODS We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, early embryos, sperm cells, and several somatic tissues by means of a quantitative reverse- transcriptase–polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. RESULTS We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. CONCLUSIONS TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility. (Funded by the National Basic Research Program of China and others.

    Lack of cyclical fluctuations of endometrial GLUT4 expression in women with polycystic ovary syndrome: Evidence for direct regulation of GLUT4 by steroid hormones

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    Background Determination of the role of steroid hormones in expression and regulation of endometrial glucose transport 4 (GLUT4) in humans is important for understanding endometrial disorders such as polycystic ovary syndrome (PCOS), a common hormone-imbalance disease. Methods Endometrial biopsy samples were collected from non-PCOS patients with regular menstrual cycles or with hyperplasia and from PCOS patients with or without hyperplasia. In addition, endometrial tissues from postmenopausal women were incubated with human chorionic gonadotropin (hCG, 10 IU/ml), 17β-estradiol (E2, 10 nM), progesterone (P4, 100 nM), or a combination of E2 and P4 for 24 h. The expression of GLUT4 was measured at the mRNA level using quantitative real-time polymerase chain reaction (qRT-PCR) and at the protein level using Western blot analysis and immunohistochemistry. Results A cyclical change in GLUT4 expression pattern was observed in non-PCOS patients, and a high level of GLUT4 expression was seen in the proliferative phase compared to the secretory phase. Low levels of GLUT4 expression were found in PCOS patients compared to menstrual cycle phase-matched non-PCOS patients, and there was no significant change in GLUT4 expression in PCOS patients during the menstrual cycle. GLUT4 was localized in both epithelial and stromal cells, with notable changes in epithelial cells. We postulate that decreased GLUT4 expression might be regulated by steroid hormones. In support of this, we showed that in cultured endometrial tissues hCG and E2 alone had no effect on GLUT4 expression. However, P4 alone and P4 in combination with E2 decreased GLUT4 expression. Compared with non-PCOS controls, PCOS patients with endometrial hyperplasia exhibited decreased GLUT4 expression in particular in the epithelial cells. Conclusion We conclude that P4 can induce changes in endometrial GLUT4 expression during the menstrual cycle and that abnormal hormonal conditions such as PCOS disrupt normal patterns of GLUT4 expression in endometrial cells

    Comparison of the diagnostic values of circulating steroid hormones, VEGF-A, PIGF, and ADAM12 in women with ectopic pregnancy

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    <p>Abstract</p> <p>Background</p> <p>Several peripheral proteins that might be useful for detecting the presence of ectopic pregnancy (EP) have been evaluated, but none have been proven entirely useful in the clinic. We investigated the presence and the possible changes in circulating molecules that distinguish between normal intrauterine pregnancy (IUP) and tubal ectopic pregnancy.</p> <p>Methods</p> <p>Non-pregnant women during the menstrual cycle, women with IUP, and women with tubal EP after informed consent. Serum levels of 17β-estradiol (E2), progesterone (P4), testosterone (T), beta-human chorionic gonadotropin (β-hCG), vascular endothelial growth factor-A (VEGF-A), placental growth factor (PIGF), and a distintegrin and metalloprotease protein 12 (ADAM12) were analyzed. Receiver operating characteristic analysis was used to assess the diagnostic discrimination of EP and gestational age-matched IUP.</p> <p>Results</p> <p>E2, P4, PIGF, and ADAM12 levels increased and β-hCG decreased throughout IUP. E2 and VEGF-A levels were significantly different between women with tubal EP and IUP. However, using a serum β-hCG cut-off of less than 1000 mIU/mL, P4 was significantly lower in women with tubal EP compared to IUP. Although E2 was inversely correlated with VEGF-A in women in the early stages of IUP, E2 was not correlated with VEGF-A in women with EP prior to tubal surgery. There were no significant differences in either PIGF or ADAM12 alone between women with tubal EP or IUP. Although no significant correlations were seen between E2 and PIGF or P4 and ADAM12 in women in the early stages of IUP, E2 was positively correlated with PIGF and P4 was positively correlated with ADAM12 in women with EP prior to tubal surgery. Our studies defined associations but not causality.</p> <p>Conclusions</p> <p>Individual measurements of serum E2 or VEGF-A levels are strongly related to early pregnancy outcomes for women with IUP and EP, and pregnancy-associated E2 and VEGF-A levels provide diagnostic accuracy for the presence of tubal EP. This study demonstrates that correlation analysis of E2/VEGF-A and E2/PIGF serum levels may be able to distinguish a tubal EP from a normal IUP.</p

    Regional aerosol forecasts based on deep learning and numerical weather prediction

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    Abstract Atmospheric chemistry transport models have been extensively applied in aerosol forecasts over recent decades, whereas they are facing challenges from uncertainties in emission rates, meteorological data, and over-simplified chemical parameterizations. Here, we developed a spatial-temporal deep learning framework, named PPN (Pollution-Predicting Net for PM2.5), to accurately and efficiently predict regional PM2.5 concentrations. It has an encoder-decoder architecture and combines the preceding PM2.5 observations and numerical weather prediction. Besides, the model proposes a weighted loss function to promote the forecasting performance in extreme events. We applied the proposed model to forecast 3-day PM2.5 concentrations over the Beijing-Tianjin-Hebei region in China on a three-hour-by-three-hour basis. Overall, the model showed good performance with R 2 and RMSE values of 0.7 and 17.7 μg m−3, respectively. It could capture the high PM2.5 concentration in the south and relatively low concentration in the north and exhibit better performance within the next 24 h. The use of the weighted loss function decreased the level of “high values underestimation, low values overestimation”, while incorporating the preceding PM2.5 observations into the encoder phase improved the predictive accuracy within 24 h. We also compared the model result with that from a state-of-the-art numerical model (WRF-Chem with pollutant data assimilation). The temporal R 2 and RMSE from the WRF-Chem were 0.30−0.77 and 19−45 μg m−3 while those from the PPN model were 0.42−0.84 and 15−42 μg m−3. The proposed model shows powerful capacity in aerosol forecasts and provides an efficient and accurate tool for early warning and management of regional pollution events

    Metabolic Biomarkers of Mediterranean Diet in Pregnant Women

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    Objectives: Using an untargeted approach to identify plasma metabolomics signature of the Mediterranean diet, a healthful dietary pattern related to both maternal and fetal outcomes, in pregnancy. Methods: This study included 193 pregnant women from the NICHD Fetal Growth Studies-Singletons (FGS) cohort who had habitual dietary intake in the past three months measured at 8–13 gestational weeks (GW) by the semi-quantified food frequency questionnaire. Fasting plasma metabolomics profiles at 15–26 GW were measured by the high-throughput liquid chromatography quadrupole time of-flight mass spectrometry (LC-QTOF MS/MS). Metabolites were re-scaled to a median of 1 for each batch and log transformed. Alternate Mediterranean Diet (aMED) score was calculated by eight food and nutrient components (i.e., fruits, vegetables, whole grains, nuts, fish, legumes, red and processed meats, and monounsaturated-to-saturated fat ratio), with a higher score indicating a better adherence. Prospective associations of aMED score in peri-conception and early pregnancy with individual metabolites at 15–26 GW were estimated using the linear regression adjusting for potential confounders and multiple testing. LASSO (Least Absolute Shrinkage and Selection Operator) regression with 10-fold cross-validation was performed to select metabolites that were jointly associated with high aMED score (defined as the top tertile). All statistical analyses were weighted to represent the entire FGS cohort. Results: A total of 460 known metabolites were profiled and annotated. Six metabolites were selected as the biomarkers of high aMED score by the LASSO regression (i.e., with no-zero coefficients). Among them, glutamic acid and 3-hydroxybutyric acid were negatively whereas PC (40:7), CE (20:5), TG (49:1), and TG (58:4) were positively associated with aMED score. The six biomarkers were also confirmed by the linear regression with false discovery rates < 0.1. Conclusions: Our study is the first one conducted in pregnant women using the untargeted metabolomics approach and we newly identified several biomarkers of Mediterranean diet in pregnant women. Results from this study warrant the replication by future studies
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