Social Group Buying as a Marketing Strategy

Social group buying (SGB) is a novel form of group buying that encourages customers to purchase deeply discounted products together with friends. Over the past few years, SGB has become a popular marketing strategy for online sellers to acquire new customers. Using a dataset from an e-commerce platform, we investigate whether and how SGB affects the sales of sellers. We find that enrolling a few products into SGB has a positive spillover effect on the sales of the sellers’ other products, and the effect varies substantially across different types of sellers. Specifically, the positive spillover effect is larger for smaller sellers and more diversified sellers. Moreover, we find that the spillover effect exhibits similar heterogeneity at the brand level, except that it can be negative for large brands and non-diversified brands. This finding suggests that sellers may gain from SGB at the expense of large or non-diversified brands

Hemodynamic Regulation of Inflammation at the Endothelial-Neutrophil Interface

Arterial shear stress can regulate endothelial phenotype. The potential for anti-inflammatory effects of shear stress on TNFα-activated endothelium was tested in assays of cytokine expression and neutrophil adhesion. In cultured human aortic endothelial cells (HAEC), arterial shear stress of 10 dyne/cm2 blocked by \u3e 80% the induction by 5 ng/ml TNFα of interleukin-8 (IL-8) and IL-6 secretion (50% and 90% reduction, respectively, in the presence of nitric oxide synthase antagonism with 200 μM nitro-L-arginine methylester, L-NAME). Exposure of TNFα-stimulated HAEC to arterial shear stress for 5 hr also reduced by 60% (P &#; 0.001) the conversion of neutrophil rolling to firm arrest in a venous flow assay conducted at 1 dyne/cm2. Also, neutrophil rolling lengths at 1 dyne/cm2 were longer when TNFα-stimulated HAEC were presheared for 5 hr at arterial stresses. In experiments with a synthetic promoter that provides luciferase induction to detect cis interactions of glucocorticoid receptor (GR) and NFκB, shear stress caused a marked 40-fold induction of luciferase in TNFα-treated cells, suggesting a role for GR pathways in the anti-inflammatory actions of fluid shear stress. Hemodynamic force exerts anti-inflammatory effects on cytokine activated endothelium by attenuation of cytokine expression and neutrophil firm arrest

Systems Biology of Coagulation Initiation: Kinetics of Thrombin Generation in Resting and Activated Human Blood

Blood function defines bleeding and clotting risks and dictates approaches for clinical intervention. Independent of adding exogenous tissue factor (TF), human blood treated in vitro with corn trypsin inhibitor (CTI, to block Factor XIIa) will generate thrombin after an initiation time (Ti) of 1 to 2 hours (depending on donor), while activation of platelets with the GPVI-activator convulxin reduces Ti to ∼20 minutes. Since current kinetic models fail to generate thrombin in the absence of added TF, we implemented a Platelet-Plasma ODE model accounting for: the Hockin-Mann protease reaction network, thrombin-dependent display of platelet phosphatidylserine, VIIa function on activated platelets, XIIa and XIa generation and function, competitive thrombin substrates (fluorogenic detector and fibrinogen), and thrombin consumption during fibrin polymerization. The kinetic model consisting of 76 ordinary differential equations (76 species, 57 reactions, 105 kinetic parameters) predicted the clotting of resting and convulxin-activated human blood as well as predicted Ti of human blood under 50 different initial conditions that titrated increasing levels of TF, Xa, Va, XIa, IXa, and VIIa. Experiments with combined anti-XI and anti-XII antibodies prevented thrombin production, demonstrating that a leak of XIIa past saturating amounts of CTI (and not “blood-borne TF” alone) was responsible for in vitro initiation without added TF. Clotting was not blocked by antibodies used individually against TF, VII/VIIa, P-selectin, GPIb, protein disulfide isomerase, cathepsin G, nor blocked by the ribosome inhibitor puromycin, the Clk1 kinase inhibitor Tg003, or inhibited VIIa (VIIai). This is the first model to predict the observed behavior of CTI-treated human blood, either resting or stimulated with platelet activators. CTI-treated human blood will clot in vitro due to the combined activity of XIIa and XIa, a process enhanced by platelet activators and which proceeds in the absence of any evidence for kinetically significant blood borne tissue factor

Enhanced Bio-Barcode Immunoassay Using Droplet Digital PCR for Multiplex Detection of Organophosphate Pesticides

A bio-barcode immunoassay based on droplet digital polymerase chain reaction (ddPCR) was developed to simultaneously quantify triazophos, parathion, and chlorpyrifos in apple, cucumber, cabbage, and pear. Three gold nanoparticle (AuNP) probes and magnetic nanoparticle (MNP) probes were prepared, binding through their antibodies with the three pesticides in the same tube. Three groups of primers, probes, templates, and three antibodies were designed to ensure the specificity of the method. Under the optimal conditions, the detection limits (expressed as IC10) of triazophos, parathion, and chlorpyrifos were 0.22, 0.45, and 4.49 ng mL–1, respectively. The linear ranges were 0.01–20, 0.1–100, and 0.1–500 ng mL–1, and the correlation coefficients (R2) were 0.9661, 0.9834, and 0.9612, respectively. The recoveries and relative standard deviations (RSDs) were in the ranges of 75.5–98.9 and 8.3–16.7%. This study provides the first insights into the ddPCR for the determination of organophosphate pesticides. It also laid the foundation for high-throughput detection of other small molecules.This study was financially supported by the National Key Research Program of China (No. 2019YFC1604503), the NIEHS Superfund Research Program (No. P42 ES04699), the Central Public-interest Scientific Institution Basal Research Fund for the Chinese Academy of Agricultural Sciences (No. Y2021PT05), and the Ningbo Innovation Project for Agro-Products Quality and Safety (No. 2019CXGC007).Peer reviewe

A highly sensitive bio-barcode immunoassay for multi-residue detection of organophosphate pesticides based on fluorescence anti-quenching

Balancing the risks and benefits of organophosphate pesticides (OPs) on human and environmental health relies partly on their accurate measurement. A highly sensitive fluorescence anti-quenching multi-residue bio-barcode immunoassay was developed to detect OPs (triazophos, parathion, and chlorpyrifos) in apples, turnips, cabbages, and rice. Gold nanoparticles were functionalized with monoclonal antibodies against the tested OPs. DNA oligonucleotides were complementarily hybridized with an RNA fluorescent label for signal amplification. The detection signals were generated by DNA-RNA hybridization and ribonuclease H dissociation of the fluorophore. The resulting fluorescence signal enables multiplexed quantification of triazophos, parathion, and chlorpyrifos residues over the concentration range of 0.01–25, 0.01–50, and 0.1–50 ng/mL with limits of detection of 0.014, 0.011, and 0.126 ng/mL, respectively. The mean recovery ranged between 80.3% and 110.8% with relative standard deviations of 7.3%–17.6%, which correlate well with results obtained by LC-MS/MS. The proposed bio-barcode immunoassay is stable, reproducible and reliable, and is able to detect low residual levels of multi-residue OPs in agricultural products.This work was supported by the Central Public Interest Scientific Institution Basal Research Fund for the Chinese Academy of Agricultural Sciences (Grant No.: Y2021PT05), National Institute of Environmental Health Science Superfund Research Program (Grant No.: P42 ES004699), National Academy of Sciences (Subaward No.: 2000009144), and Ningbo Innovation Project for Agro-Products Quality and Safety (Grant No.: 2019CXGC007).Peer reviewe

Anticipation of negative pictures enhances the P2 and P3 in their later recognition

Anticipation of emotional pictures has been found to be relevant to the encoding of the pictures as well as their later recognition performance. However, it is as yet unknown whether anticipation modulates neural activity in the later recognition of emotional pictures. To address this issue, participants in the present study were asked to view emotional (negative or neutral) pictures. The picture was preceded by a cue which indicated the emotional content of the picture in half of the trials (the anticipated condition) and without any cues in the other half (the unanticipated condition). Subsequently, participants had to perform an unexpected old/new recognition task in which old and novel pictures were presented without any preceding cues. Electroencephalography (EEG) data was recorded during the recognition phase. Event-related potential (ERP) results showed that for negative pictures, P2 and P3 amplitudes were larger in the anticipated as compared to the unanticipated condition; whereas this anticipation effect was not shown for neutral pictures. The present findings suggest that anticipation of negative pictures may enhance neural activity in their later recognition

Experimental Research on the Influence of Short-Term Noise Exposure on Miners’ Physiology

Coal mine noise affects human physiology, psychology, and behavior. It causes errors at work and increases accidents. In this study, we built a coal mine noise simulation experiment system. The system not only included an experimental environment simulation system and a physiological indicator test system, but it also added a miners’ working simulation system. This paper aimed to study the effect of different short-term (25 min) noise levels (60 dB, 70 dB, 80 dB, 90 dB, and 100 dB) on human physiology (skin conductivity and heart rate). Critical analysis showed that the stronger the noise intensity is, the shorter the contact time it takes for physiological indicators to present significant changes, and by setting different noises and measuring the skin conductivity and heart rate of human body, it was concluded that the noise level should be reduced to 90 dB to reduce accidents of miners

Experimental Research on the Influence of Short-Term Noise Exposure on Miners’ Physiology

Coal mine noise affects human physiology, psychology, and behavior. It causes errors at work and increases accidents. In this study, we built a coal mine noise simulation experiment system. The system not only included an experimental environment simulation system and a physiological indicator test system, but it also added a miners’ working simulation system. This paper aimed to study the effect of different short-term (25 min) noise levels (60 dB, 70 dB, 80 dB, 90 dB, and 100 dB) on human physiology (skin conductivity and heart rate). Critical analysis showed that the stronger the noise intensity is, the shorter the contact time it takes for physiological indicators to present significant changes, and by setting different noises and measuring the skin conductivity and heart rate of human body, it was concluded that the noise level should be reduced to 90 dB to reduce accidents of miners