Online Content Consumption: Social Endorsements, Observational Learning and Word-of-Mouth

The consumption of online content can occur through observational learning (OL) whereby consumers follow previous consumers’ choices or social endorsement (SE) wherein consumers receive content sharing from their social ties. As users consume content, they also generate post-consumption word-of-mouth (WOM) signals. OL, SE and WOM together shape the diffusion of the content. This study examines the drivers of SE and the effect of SE on content consumption and post-consumption WOM. In particular, we compare SE with OL. Using a random sample of 8,945 new videos posted on YouTube, we collected a multi-platform dataset consisting of data on video consumption and WOM from YouTube and data on tweet sharing of the video from Twitter. Applying a panel vector autoregression (PVAR) model, we find that OL increases consumption significantly more than SE in the short run. However, SE has a stronger effect on content consumption in the long run. This can be attributed to the impact of SE on WOM signals, which also increase content consumption. While OL and SE leads to similar amount of positive WOM, SE generates significantly more negative WOM than OL. Our results also show that SE is driven by WOM (i.e., likes and dislikes) but not content popularity. We further confirm the effects of OL vs. SE on content consumption and WOM using a randomized experiment at the individual consumer level. Implications for content providers and social media platforms are derived accordingly

High channel count and high precision channel spacing multi-wavelength laser array for future PICs

Multi-wavelength semiconductor laser arrays (MLAs) have wide applications in wavelength multiplexing division (WDM) networks. In spite of their tremendous potential, adoption of the MLA has been hampered by a number of issues, particularly wavelength precision and fabrication cost. In this paper, we report high channel count MLAs in which the wavelengths of each channel can be determined precisely through low-cost standard μm-level photolithography/holographic lithography and the reconstruction-equivalent-chirp (REC) technique. 60-wavelength MLAs with good wavelength spacing uniformity have been demonstrated experimentally, in which nearly 83% lasers are within a wavelength deviation of ±0.20 nm, corresponding to a tolerance of ±0.032 nm in the period pitch. As a result of employing the equivalent phase shift technique, the single longitudinal mode (SLM) yield is nearly 100%, while the theoretical yield of standard DFB lasers is only around 33.3%

Orexin-A protects against oxygen-glucose deprivation/reoxygenation-induced cell damage by inhibiting endoplasmic reticulum stress-mediated apoptosis via the Gi and PI3K signaling pathways

The neuropeptide orexin-A (OXA) has a neuroprotective effect, acting as an anti-apoptotic factor in response to multiple stimuli. Apoptosis induced by endoplasmic reticulum stress (ERS) underlies oxygen-glucose deprivation and reoxygenation (OGD/R)-induced cell damage, an in vitro model of ischemia/reperfusion injury. However, that OXA inhibits ERS-induced apoptosis in the OGD/R model has not been reported. In the present study, we investigated the neuroprotective effect of OXA (0.1 μM) on OGD/R-induced damage in the human neuroblastoma cell line SH-SY5Y. After OXA treatment following 4 h oxygen-glucose deprivation (OGD) and then 4 h reoxygenation (R), cell morphology, viability, and apoptosis were analyzed by histology, Cell Counting Kit-8 assay, and flow cytometry, respectively. Western blotting was used to measure expression levels of ERS- and apoptosis-related proteins. To determine signaling pathways involved in OXA-mediated neuroprotection, the Gi pathway inhibitor pertussis toxin (PTX; 100 ng/mL) and PI3K inhibitor LY294002 (LY; 10 μM) were added. In addition, in order to prove the specificity of these characteristics, the OXA antagonist Suvorexant (DORA; Ki of 0.55 nM and 0.35 nM for OX1R and OX2R) was used for intervention. Our results showed that OGD/R induced cell damage, manifested as morphological changes and a significant decrease in viability. Furthermore, Western blotting detected an increase in ERS-related proteins GRP78, p-IRE1α, p-JNK, and Cleaved caspase-12, as well as apoptosis-related proteins Cleaved caspase-3 and Bax, and a decrease in the anti-apoptosis factor Bcl-2. OXA intervention alleviated the degree of cellular damage, and protein expression was also reversed. In addition, the protective effect of OXA was reduced by adding PTX and LY. Meanwhile, after the use of DORA, changes in the expression of related proteins were detected, and it was found that the protective effect of OXA was weakened. Collectively, our results indicate that OXA has a neuroprotective effect on OGD/R-induced cell damage by inhibiting ERS-induced apoptosis through the combined action of Gi and PI3K signaling pathways. These findings help to clarify the mechanism underlying the neuroprotective action of OXA, which should aid the development of further candidate drugs, and provide a new therapeutic direction for the treatment of ischemic stroke

Heightened expression of MICA enhances the cytotoxicity of NK cells or CD8+T cells to human corneal epithelium in vitro

BACKGROUND: Major-histocompatibility-complex class I-related chain A (MICA) antigens are the ligands of NKG2D, which is an activating or coactivating receptor expressed on human NK cells and CD8(+)T cells. We sought to determine whether MICA expression in human corneal epithelium (HCE) could affect the cytotoxicity mediated by NK cells or CD8(+)T cells. METHODS: Cell cultures of HCE were harvested from human donor eyes. Flow cytometric analysis and ELISA was performed to determine the levels of MICA expression on HCE. Then, HCE was transfected with a lentivirus vector expressing MICA and GFP. Flow cytometric analysis, RT-PCR, western blot and ELISA were performed to check the levels of MICA expression. For cytotoxicity testing, allogeneic NK cells and CD8(+)T cells were isolated from peripheral blood mononuclear cells of healthy volunteers by magnetic cell sorting. The cytolytic activity of NK cells and CD8(+)T cells was assessed against MICA-transfected HCE (NK cells: E:T ratio = 3:1; CD8(+)T cells: E:T ratio = 10:1) using the nonradioactive cytotoxicity detection kit lactate deshydrogenase. RESULTS: Surface expression of MICA on corneal epithelium was identified at a low level. A cell line of stable human MICA-transfected corneal epithelium was successfully established. Heightened expression of MICA on HCE was found to promote the cytotoxicity mediated by NK cells or CD8(+)T cells, which could be blocked by an anti-MICA antibody. CONCLUSION: MICA molecules may contribute to cytotoxic responses mediated by activated immune effector cells in corneal epithelium immunity

Sigma metrics for assessing the analytical quality of clinical chemistry assays: a comparison of two approaches

Introduction: Two approaches were compared for the calculation of coefficient of variation (CV) and bias, and their effect on sigma calculation, when different allowable total error (TEa) values were used to determine the optimal method for Six Sigma quality management in the clinical laboratory. Materials and methods: Sigma metrics for routine clinical chemistry tests using three systems (Beckman AU5800, Roche C8000, Siemens Dimension) were determined in June 2017 in the laboratory of Peking Union Medical College Hospital. Imprecision (CV%) and bias (bias%) were calculated for ten routine clinical chemistry tests using a proficiency testing (PT)- or an internal quality control (IQC)-based approach. Allowable total error from the Clinical Laboratory Improvement Amendments of 1988 and the Chinese Ministry of Health Clinical Laboratory Center Industry Standard (WS/ T403-2012) were used with the formula: Sigma = (TEa − bias) / CV to calculate the Sigma metrics (σCLIA, σWS/T) for each assay for comparative analysis. Results: For the PT-based approach, eight assays on the Beckman AU5800 system, seven assays on the Roche C8000 system and six assays on the Siemens Dimension system showed σCLIA > 3. For the IQC-based approach, ten, nine and seven assays, respectively, showed σCLIA > 3. Some differences in σ were therefore observed between the two calculation methods and the different TEa values. Conclusions: Both methods of calculating σ can be used for Six Sigma quality management. In practice, laboratories should evaluate Sigma multiple times when optimizing a quality control schedule

A novel long non-coding RNA, AC012456.4, as a valuable and independent prognostic biomarker of survival in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a major malignant cancer of the head and neck. Long non-coding RNAs (lncRNAs) have emerged as critical regulators during the development and progression of cancers. This study aimed to identify a lncRNA-related signature with prognostic value for evaluating survival outcomes and to explore the underlying molecular mechanisms of OSCC. Associations between overall survival (OS), disease-free survival (DFS) and candidate lncRNAs were evaluated by Kaplan–Meier survival analysis and univariate and multivariate Cox proportional hazards regression analyses. The robustness of the prognostic significance was shown via the Gene Expression Omnibus (GEO) database. A total of 2,493 lncRNAs were differentially expressed between OSCC and control samples (fold change >2, p < 0.05). We used Kaplan–Meier survival analysis to identify 21 lncRNAs for which the expression levels were associated with OS and DFS of OSCC patients (p < 0.05) and found that down-expression of lncRNA AC012456.4 especially contributed to poor DFS (p = 0.00828) and OS (p = 0.00987). Furthermore, decreased expression of AC012456.4 was identified as an independent prognostic risk factor through multivariate Cox proportional hazards regression analyses (DFS: p = 0.004, hazard ratio (HR) = 0.600, 95% confidence interval(CI) [0.423–0.851]; OS: p = 0.002, HR = 0.672, 95% CI [0.523–0.863). Gene Set Enrichment Analysis (GSEA) indicated that lncRNA AC012456.4 were significantly enriched in critical biological functions and pathways and was correlated with tumorigenesis, such as regulation of cell activation, and the JAK-STAT and MAPK signal pathway. Overall, these findings were the first to evidence that AC012456.4 may be an important novel molecular target with great clinical value as a diagnostic, therapeutic and prognostic biomarker for OSCC patients

Stability of novel urinary biomarkers used for lupus nephritis

BackgroundThe Renal Activity Index for Lupus (RAIL) is a composite score of six urinary biomarkers (neutrophil gelatinase–associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), kidney injury molecule-1 (KIM-1), ceruloplasmin, adiponectin, and hemopexin) used to monitor lupus nephritis activity in children. We tested stability of RAIL biomarkers prior to meaningful clinical use.MethodsUrine samples were tested by ELISA under shipping conditions, freeze/thaw, ambient and longer-term storage. Statistical analysis was performed via Deming Regression, Bland-Altman and Spearman Correlation Coefficient.ResultsBiomarker concentration were comparable to freshly collected urine following storage at −80 °C for up to 3 months, and at 4 or 25 °C up to 48 h followed by −80 °C. Neither shipping on dry or wet ice exposure nor addition of two freeze-thaw cycles led to loss of signal, with excellent Spearman Correlation coefficients under all conditions.ConclusionsRAIL biomarkers are stable following short-term storage at clinically relevant conditions