Search

Firms using e-commerce as platforms need to develop effective mechanisms to govern seller opportunism. This paper attempts to explore the effect of seller community engagement, as an informal mechanism of network governance, on seller opportunistic behaviors. In particular, we identify two types of the seller community established by the e-commerce platforms, which offers infrastructures supporting tightly and loosely coupled relationships among members, respectively. We find that engaging in both types of communities reduces seller opportunistic behaviors. We also show that the intensity of competition positively moderates the relationship between engagement in the communities with tight infrastructure and sellers’ opportunistic behaviors, while deterrence perception exerts a negative moderating effect on the relationship. In contrast, the intensity of competition negatively moderates the relationship between engagement in communities with loose infrastructure and opportunistic behaviors. The findings provide theoretical and managerial implications for opportunism governance in electronic markets.

Purpose: To evaluate the inter- and intra-observer reliability of anterior chamber (AC) angle measurements obtained by swept-source optical coherence tomography (SS-OCT).Methods: Forty-eight consecutive patients diagnosed with primary angle closure suspect (PACS) were included. Three masked observers at different training levels (one glaucoma specialist, one ophthalmology resident, and one pre-medical college student) measured 192 SS-OCT images of the PACS patients. One observer (the glaucoma specialist) repeated measurements 1week later. SS-OCT parameters included: Anterior segment volume, including corneal, AC, and iris volume; anterior segment dimensions, including AC depth and width (ACD, ACW), and lens vault (LV); and angle parameters, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and the trabecular iris angle (TIA). Intraclass correlation coefficients (ICCs) were used to measure reliability.Results: For inter-observer reproducibility, ICCs of corneal, AC, and iris volumes were 0.952 to 0.998. ICCs of ACD at all axes were above 0.989. ICCs of ACW and LV were smallest in the 90°-270° axis (0.751 and 0.768) but not significantly different from other axes. ARA, TISA, and TIA at all angles had significantly smallest ICCs 250µm from the scleral spur compared with 500µm and 750µm. The ICCs comparing observers with different training levels had similar ranges and followed similar trends. For intra-observer repeatability, the smallest ICC was 0.843. Decreasing AC depth correlated with increased inter-observer reproducibility.Conclusions: We found excellent intra-observer repeatability for all SS-OCT parameters. Angle measurements have more variation among the observers when taken 250µm from the scleral spur. Shallow AC might lead to more variability for angle parameters. Non-expert observers may be recruited for high-quality image grading with standard training.

Glaucoma is a heterogeneous group of progressive optic neurodegenerative. Although most patients with primary open angle glaucoma (POAG) are stable for many years, certain subgroups of POAG patients could progress over time even with treatment. This study is to identify aqueous humor (AH) biomarkers that may be associated with disease progression in POAG patients. Gene differential expression study of prospectively collected AH from patients with stable or progressive POAG. Metagenomic deep sequencing (MDS) was performed on the aqueous fluid of 20 patients with stable POAG and 20 patients with progressive POAG. Differential gene expression analysis was performed to identify host transcriptome signatures. A total of 21 transcripts were differentially expressed between groups. Differential transcripts identified by MDS. Twenty transcripts were up-regulated and 1 transcript was down-regulated in progressive POAG patients compared to stable patients. Of those, 11 transcripts were eye-related, and 5 transcripts were related to glaucomatous phenotypes (Fibronectin type III domain containing 3B (FNDC3B), Clusterin (CLU), Proprotein convertase subtilisin/kexin type 6 (PCSK6), Cadherin EGF LAG seven-pass G-type receptor 1 (Celsr1), and Rho guanine nucleotide exchange factor 4 (ARHGEF4)). Biomarkers associated with POAG progression can be identified from aqueous fluid. Identification of the biomarkers may improve glaucoma surveillance for progressive POAG.

Compared with normal subjects with similar shallow anterior chamber depth (ACD), patients with primary angle closure disease (PACD) had narrower angle structures measured by swept-source optical coherence tomography (SS-OCT) at 250 μm from scleral spur (very root of iris), especially along oblique and vertical axis.To examine anterior segment structures in normal subjects whose ACD was shallow on slit-lamp examination but did not meet the diagnostic criteria of PACD, and to compare them with PACD patients with similar ACD.Patients were recruited from glaucoma clinic at Zhongshan Ophthalmic Center. A total of 40 eyes from 29 PACD patients and 40 eyes from 34 normal subjects received full ophthalmic examination and CASIA SS-1000 OCT tests. PACD eyes and control eyes were 1:1 matched for ACD at 0 degree of scan. Generalized linear model that accounted for inter-eye correlation was used to compare differences between the 2 groups for intraocular pressure and SS-OCT parameters. P-values were adjusted for multiple comparisons using the Bonferroni method.The PACD and control groups had similar age, but the PACD group had a significantly higher intraocular pressure (18.4 vs. 14.0 mm Hg, P=0.005). Angle parameters, representative of angle area, such as angle recess area and trabecular iris space area measured at 250 μm along axes of 90, 135, 225, and 315 degrees were significantly smaller in PACD group than those of control group (adjusted P0.05), while most of angle parameters at 500 and 750 μm, volume parameters, and anterior chamber parameters, were similar (adjusted P0.05).In PACD patients compared with normal subjects with similar anterior chamber shallowing, OCT findings measured at the iris root 250 μm from the scleral spur, especially in the oblique and vertical axes, including angle recess area and trabecular iris space area, may match gonioscopic findings more closely and provide further insight into mechanisms of PACD.

The purpose of the study is to assess the prevalence of visual impairment (PVI) among rural residents aged 50 years and above in Yugan county, China. Researchers analyzed risk factors and obtained scientific baseline information for blindness prevention and control.Stratified cluster random sampling was used in randomly selecting 5540 rural residents aged ≥50 in Yugan county. Eligible residents were invited to receive visual acuity measurement via ophthalmic examinations. Multivariable logistic regression was performed to analyze any risk factors.A total of 5119 rural residents participated the ophthalmic examination and investigation. The PVI was 19.2%. The prevalence of moderate and severe visual impairment (≥20/400 and20/60) was 16.9%, and blindness (20/400) was 2.27%. Multivariable logistic regression showed that age, gender, education, occupation, marital status, drinking attitude, dietary habits, amount of sleep, and daily fruit intake were the main factors that were most predictive of the PVI.The PVI among rural residents aged 50 years and above in Yugan county was higher than many other districts. Preventive work in Yuan and other local regions should be focused on older, separated/divorced, or widowed individuals, and those with a lower level of education. Strengthening public awareness consists of educating the public about visual health promotion and blindness intervention, including healthy diet and healthy habits, which will help to reduce visual impairment of the population.

The objectives of this study were to examine the association between PM2.5-associated polycyclic aromatic hydrocarbons (PAHs) and their meteorological factors, and the relationship between PM2.5-associated PAH concentrations and temperature, air pressure and air humidity. Data collected by Center for Disease Control (CDC) in Nanchang urban areas during the fall and winter seasons of 2014–2015 were analyzed by using high performance liquid chromatography (HPLC). Our study showed that the PM2.5 mass concentration had a mean of 0.088 µg m–3. Our results showed that the total concentration of PAHs in Nanchang was 22.54 ng m–3 (RSD: 8.50) and 15 different types of PAHs examined in this study all exceeded the China national standard. Multiple regression analysis revealed that the daily average concentration of total PAH was significantly associated with the temperature and daily minimum humidity (p < 0.05), but not daily wind speed and rainfall. Principal component analysis and characteristic ratio study indicated that the source of PAHs in PM2.5 were mainly from vehicle exhaust and coal and gas combustion in Nanchang.