323 research outputs found

    Psychological Contract Breach and Customer Satisfaction: A Study of Online Shopping

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    Online shopping is becoming increasingly popular among customers in recent years. It offers customers numerous advantages and benefits, such as convenience in terms of time and place, better prices, and a variety of options. However, the number of customers who complain about online shopping is also increasing. Therefore, it is important for online retailers to better understand how customers respond to failures in customers’ online shopping. Prior research on service failures and customer complaints has largely used expectation-dissatisfaction model to explain the phenomenon (e.g., McCollough, Berry, and Yadav 2000) and suggests approaches to address customer complaints (e.g., Hess, Ganesan, and Klein 2003). The current study takes a psychological contracts perspective and investigates its role in customers’ reactions to service failures. We propose that psychological contracts are held by customers, representing customers’ beliefs about obligations between them and the company. In two experiments, we find that when customers encounter a service failure, they will perceive that there is a breach in the psychological contract, which leads to negative reactions. In addition, the findings from Experiment 1 show that customers’ attribution of breach to intentional rather than misunderstanding will accentuate the relationship between the perceived breach and customers’ negative reactions. Further, we show in Experiment 2 that customers will react less negatively to service failures when they are notified on how the company will handle the service failures than why the failures occurred. The current research will make several theoretical and practical contributions. It examines psychological contract breach as the underlying mechanism for why customers are dissatisfied with online service failures. Two moderators are identified to influence the strength of the relationship to address the inconsistent findings in previous research. Based on above findings, we proposed approaches for companies to communicate more effectively to customers to mitigate customers’ negative reactions to service failures

    From Customizing Products to Possessive Bonds: The Role of Consumer Involvement and Consumer Privacy Concern

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    Despite the prevalence of customized products and service in the marketplace, little research has examined the impact of customization on consumers. The current research investigates the role of brand customization on consumers’ brand relationship and brand attitude. The findings from two experiments demonstrate that consumers with high involvement (vs. low) will have more positive brand relationship and brand attitude. In addition, consumer’s privacy concern moderates this relationship such that the identified positive effect exists only for those with a low privacy concern

    Human beta defensin 2 selectively inhibits HIV-1 in highly permissive CCR6+CD4+ T cells

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    Chemokine receptor type 6 (CCR6)+CD4+ T cells are preferentially infected and depleted during HIV disease progression, but are preserved in non-progressors. CCR6 is expressed on a heterogeneous population of memory CD4+ T cells that are critical to mucosal immunity. Preferential infection of these cells is associated, in part, with high surface expression of CCR5, CXCR4, and α4β7. In addition, CCR6+CD4+ T cells harbor elevated levels of integrated viral DNA and high levels of proliferation markers. We have previously shown that the CCR6 ligands MIP-3α and human beta defensins inhibit HIV replication. The inhibition required CCR6 and the induction of APOBEC3G. Here, we further characterize the induction of apolipoprotein B mRNA editing enzyme (APOBEC3G) by human beta defensin 2. Human beta defensin 2 rapidly induces transcriptional induction of APOBEC3G that involves extracellular signal-regulated kinases 1/2 (ERK1/2) activation and the transcription factors NFATc2, NFATc1, and IRF4. We demonstrate that human beta defensin 2 selectively protects primary CCR6+CD4+ T cells infected with HIV-1. The selective protection of CCR6+CD4+ T cell subsets may be critical in maintaining mucosal immune function and preventing disease progression

    ZSTAD: Zero-Shot Temporal Activity Detection

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    An integral part of video analysis and surveillance is temporal activity detection, which means to simultaneously recognize and localize activities in long untrimmed videos. Currently, the most effective methods of temporal activity detection are based on deep learning, and they typically perform very well with large scale annotated videos for training. However, these methods are limited in real applications due to the unavailable videos about certain activity classes and the time-consuming data annotation. To solve this challenging problem, we propose a novel task setting called zero-shot temporal activity detection (ZSTAD), where activities that have never been seen in training can still be detected. We design an end-to-end deep network based on R-C3D as the architecture for this solution. The proposed network is optimized with an innovative loss function that considers the embeddings of activity labels and their super-classes while learning the common semantics of seen and unseen activities. Experiments on both the THUMOS14 and the Charades datasets show promising performance in terms of detecting unseen activities

    Study of Histopathological and Molecular Changes of Rat Kidney under Simulated Weightlessness and Resistance Training Protective Effect

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    To explore the effects of long-term weightlessness on the renal tissue, we used the two months tail suspension model to simulate microgravity and investigated the simulated microgravity on the renal morphological damages and related molecular mechanisms. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of renal tissue morphology. The immunohistochemistry, real-time PCR and Western blot were performed to explore the molecular mechanisms associated the observations. Hematoxylin and eosin (HE) staining showed severe pathological kidney lesions including glomerular atrophy, degeneration and necrosis of renal tubular epithelial cells in two months tail-suspended rats. Ultrastructural studies of the renal tubular epithelial cells demonstrated that basal laminas of renal tubules were rough and incrassate with mitochondria swelling and vacuolation. Cell apoptosis in kidney monitored by the expression of Bax/Bcl-2 and caspase-3 accompanied these pathological damages caused by long-term microgravity. Analysis of the HSP70 protein expression illustrated that overexpression of HSP70 might play a crucial role in inducing those pathological damages. Glucose regulated protein 78 (GRP78), one of the endoplasmic reticulum (ER) chaperones, was up-regulated significantly in the kidney of tail suspension rat, which implied that ER-stress was associated with apoptosis. Furthermore, CHOP and caspase-12 pathways were activated in ER-stress induced apoptosis. Resistance training not only reduced kidney cell apoptosis and expression of HSP70 protein, it also can attenuate the kidney impairment imposed by weightlessness. The appropriate optimization might be needed for the long term application for space exploration

    A novel liposomal S-propargyl-cysteine: a sustained release of hydrogen sulfide reducing myocardial fibrosis via TGF-β1/Smad pathway

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    Purpose: S-propargyl-cysteine (SPRC; alternatively known as ZYZ-802) is a novel modulator of endogenous tissue H2S concentrations with known cardioprotective and anti-inflammatory effects. However, its rapid metabolism and excretion have limited its clinical application. To overcome these issues, we have developed some novel liposomal carriers to deliver ZYZ-802 to cells and tissues and have characterized their physicochemical, morphological and pharmacological properties. Methods :Two liposomal formulations of ZYZ-802 were prepared by thin-layer hydration and the morphological characteristics of each liposome system were assessed using a laser particle size analyzer and transmission electron microscopy. The entrapment efficiency and ZYZ-802 release profiles were determined following ultrafiltration centrifugation, dialysis tube and HPLC measurements. LC-MS/MS was used to evaluate the pharmacokinetic parameters and tissue distribution profiles of each formulation via the measurements of plasma and tissues ZYZ-802 and H2S concentrations. Using an in vivo model of heart failure (HF), the cardio-protective effects of liposomal carrier were determined by echocardiography, histopathology, western blot and the assessment of antioxidant and myocardial fibrosis markers.Results: Both liposomal formulations improved ZYZ-802 pharmacokinetics and optimized H2S concentrations in plasma and tissues. Liposomal ZYZ-802 showed enhanced cardioprotective effects in vivo. Importantly, liposomal ZYZ-802 could inhibit myocardial fibrosis via the inhibition of the TGF-β1/Smad signaling pathway. Conclusion: The liposomal formulations of ZYZ-802 have enhanced pharmacokinetic and pharmacological properties in vivo. This work is the first report to describe the development of liposomal formulations to improve the sustained release of H2S within tissues.Key word: Liposome; S-Propargyl-cysteine (SPRC, ZYZ-802); Hydrogen sulfide; Heart failure; Myocardial fibrosis; TGF-β1/Smad pathwa

    Drought stress tolerance and metabolomics of Medicago sativa induced by Bacillus amyloliquefaciens DGL1

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    IntroductionThis study used Bacillus amyloliquefaciens DGL1 isolated from the arid sandy land of the Qinghai–Tibetan Plateau as the research strain and investigated the effects of DGL1 on the biomass, physiology, and metabolites of Medicago sativa under different intensities of drought stress to provide a high-quality bacterial source and a theoretical basis for the research and development of biological fertilizer suitable for arid areas.MethodsThe exopolysaccharides (EPS), 1-Aminocyclopropane-1-carboxylate deaminase (ACC), and phosphorus solubilizing capacity of DGL1 were determined. The effects of a DGL1 suspension on alfalfa biomass, physiological indexes, degree of peroxidation of cell membranes, and activity of antioxidant enzymes were determined after irrigating roots under drought stress. The effects on soil physicochemical properties were also evaluated, and metabolomics analysis was performed to explore the effect of DGL1 on the metabolites of alfalfa under drought stress.ResultsStrain DGL1 produced extracellular polysaccharide EPS and ACC deaminase and was capable of phosphorus solubilization. Treatment with DGL1 increased the biomass of alfalfa under different degrees of drought stress, significantly increased the activities of alfalfa antioxidant enzymes Super Oxide Dismutase (SOD), Peroxidase (POD), and catalase (CAT), reduced the content of MDA and H2O2, and increased the content of quick-acting phosphorus, quick-acting potassium, ammonium nitrogen, and nitrate nitrogen in the soil, thus improving soil fertility. Through metabolomics analysis, DGL1 was shown to affect amino acid metabolic pathways, such as arginine, leucine, glutamate, and tyrosine, as well as the levels of energy-providing polysaccharides and lipids, in alfalfa under 15% PEG-6000 drought stress, enhancing alfalfa’s capacity to resist drought stress.DiscussionStrain DGL1 enhances the drought suitability of alfalfa and has the potential for dryland development as a biological agent

    Decreased Functional Connectivity in Insular Subregions in Depressive Episodes of Bipolar Disorder and Major Depressive Disorder

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    Objective: Clinically, it is very difficult to distinguish between major depressive disorder (MDD) and bipolar disorder (BD) in the period of depression. Increasing evidence shows that the insula plays an important role in depression. We aimed to compare the resting-state functional connectivity (rsFC) of insular subregions in patients with MDD and BD in depressive episodes (BDD), who had never experienced manic or hypomanic episodes when they were scanned to identify biomarkers for the identification of two diseases.Methods: We recruited 21 BDD patients, 40 MDD patients and 70 healthy controls (HC). Resting-state functional magnetic resonance imaging (rs-fMRI) was performed. BDD patients had never had manic or hypomanic episodes when they were scanned, and the diagnoses were determined by follow-up. We divided the insula into three parts including the ventral anterior insular cortex (v-AIN), dorsal anterior insular cortex (d-AIN), and posterior insula (PI). The insular-based rsFC was compared among the three groups, and an analysis of the correlation between the rsFC value and Hamilton depression and anxiety scales was carried out.Results: BDD and MDD patients demonstrated decreased rsFC from the v-AIN to the left superior/middle frontal gyrus compared with the HC group. Versus MDD and HC groups, BDD patients exhibited decreased rsFC from the v-AIN to the area in the left orbital frontal gyrus and left superior temporal gyrus (included temporal pole), from the PI to the right lateral postcentral gyrus and from all three insular subregions to the somatosensory and motor cortex. Meanwhile, a correlation between the rsFC value of the PI-right lateral postcentral gyrus and anxiety score was observed in patients.Conclusion: Our findings show BDD and MDD patients have similar decreases in insular connectivity in the dorsal lateral frontal regions, and BDD patients have specific decreased insular connectivity, especially in the somatosensory and motor cortex, which may be used as imaging evidence for clinical identification
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