Structural and optical properties of ZnS thin films deposited by RF magnetron sputtering

Zinc sulfide [ZnS] thin films were deposited on glass substrates using radio frequency magnetron sputtering. The substrate temperature was varied in the range of 100°C to 400°C. The structural and optical properties of ZnS thin films were characterized with X-ray diffraction [XRD], field emission scanning electron microscopy [FESEM], energy dispersive analysis of X-rays and UV-visible transmission spectra. The XRD analyses indicate that ZnS films have zinc blende structures with (111) preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM data also reveal that the films have nano-size grains with a grain size of approximately 69 nm. The films grown at 350°C exhibit a relatively high transmittance of 80% in the visible region, with an energy band gap of 3.79 eV. These results show that ZnS films are suitable for use as the buffer layer of the Cu(In, Ga)Se2 solar cells

Who Initiates Layoffs and Affects Firm Performance? Conflict of Interests between Active Foreign Institutional Investors and Outside Directors

Expanding upon the existing literature on agency theory, which often overlooks potential conflicting interests among monitoring mechanisms, this study investigates the divergent effects of active foreign institutional investors and outside directors on firm strategy and performance. Specifically, in light of inconclusive findings on the relationship between layoffs and performance, this study examines the initiators of layoffs and their impact on firm performance, comparing the roles of active foreign institutional investors and outside directors. Through panel data analysis of 2,516 firm-year observations from South Korea spanning 2010 to 2014, the findings reveal that firms with active foreign institutional investors are more inclined to implement large-scale layoffs, which positively moderate the relationship between active foreign institutional investors and firm performance metrics such as return on assets (ROA) and market returns. However, the relationships between active foreign institutional investors, layoffs, and performance are contingent upon the presence of outside directors on the board. Outside directors are not actively involved in initiating layoffs but tend to approve them in the context of operational performance, such as ROA, while showing less interest in layoffs as a means of external evaluation, such as market returns. These findings highlight the heterogeneous characteristics of outside directors and active foreign institutional investors with regard to layoffs and performance, and subsequently propose theoretical and managerial implications for the design of corporate governance

Toxicological Study on MUNOPHIL, Water Extract of Panax ginseng and Hericium erinaceum in Rats

AbstractObjectiveAs data on the safety profile of Panax ginseng and Hericium erinaceum is lacking, the safety of these two compounds was examined in a series of toxicological studies.Materials and MethodsMUNOPHIL, the water extract mixture of Panax ginseng and Hericium erinaceum was tested in an oral subchronic 28-day toxicity study in rats at doses of 1250, 2500 and 5000 mg/kg/day.ResultsIn repeated dose toxicity studies, no mortality was observed when varying doses of the extracts were administered once daily for a period of 28 days. There were no significant differences in body weight, absolute and relative organ weights between controls and treated rats of both sexes. Hematological analysis showed no differences in most parameters examined. In the biochemistry parameter analysis, no significant change occurred. Pathologically, neither gross abnormalities nor his-topathological changes were observed. Therefore, MUNOPHIL appears to be safe and non-toxic in these studies and a no-observed adverse effect level in rats was established at 5000 mg/kg/day.ConclusionThe data could provide satisfactory preclinical evidence of safety to launch clinical trials on standardized formulation of plant extracts

Transmission of Seasonal Outbreak of Childhood Enteroviral Aseptic Meningitis and Hand-foot-mouth Disease

This study was conducted to evaluate the modes of transmission of aseptic meningitis (AM) and hand-foot-mouth disease (HFMD) using a case-control and a case-crossover design. We recruited 205 childhood AM and 116 HFMD cases and 170 non-enteroviral disease controls from three general hospitals in Gyeongju, Pohang, and Seoul between May and August in both 2002 and 2003. For the case-crossover design, we established the hazard and non-hazard periods as week one and week four before admission, respectively. In the case-control design, drinking water that had not been boiled, not using a water purifier, changes in water quality, and contact with AM patients were significantly associated with the risk of AM (odds ratio [OR]=2.8, 2.9, 4.6, and 10.9, respectively), while drinking water that had not been boiled, having a non-water closet toilet, changes in water quality, and contact with HFMD patients were associated with risk of HFMD (OR=3.3, 2.8, 6.9, and 5.0, respectively). In the case-crossover design, many life-style variables such as contact with AM or HFMD patients, visiting a hospital, changes in water quality, presence of a skin wound, eating out, and going shopping were significantly associated with the risk of AM (OR=18.0, 7.0, 8.0, 2.2, 22.3, and 3.0, respectively) and HFMD (OR=9.0, 37.0, 11.0, 12.0, 37.0, and 5.0, respectively). Our findings suggest that person-to-person contact and contaminated water could be the principal modes of transmission of AM and HFMD

Reproductive and Hormonal Factors Associated with Fatty or Dense Breast Patterns among Korean Women

PURPOSE: Dense breasts have been suggested as a risk factor for breast cancer, but controversy still remains. This study evaluates the association of reproductive and hormonal factors with dense breasts among Korean women. MATERIALS AND METHODS: Using a cross-sectional design, 516 women were recruited and classified for breast density patterns as being either fatty or dense, using the Breast Imaging Reporting and Data System (BI-RADS) of the American College of Radiology. Univariate and multivariate logistic regression models were used for statistical analysis. RESULTS: In univariate logistic regression, older age, higher body mass index, older age at menarche, and oral contraceptive use were associated with more fatty breasts. On the contrary, longer duration of education, alcohol consumption, lower parity, menopause and use of hormone replacement therapy were associated with dense breasts. After adjustment, age and body mass index were inversely associated with breast density (p-value for trend <0.01, respectively), whereas nulliparous and premenopausal status were positively associated. Compared to women who had ≥2 children, nulliparous women had an 11.8-fold increase of dense breasts (p-value for trend <0.01). Compared to postmenopausal women, premenopausal women had 2.4-fold increase of dense breasts (odds ratio, 2.42; 95% confidence interval, 1.36 to 4.32). CONCLUSION: Young age, lower body mass index, lower parity, and premenopausal status were significantly associated with dense breasts in Koreaope

Intramural gallbladder hematoma mimicking gallbladder neoplasm in a 55-year-old male patient

Hemorrhage in the gallbladder (GB) is usually associated with cholecystitis, GB neoplasm, trauma, hemobilia, and cystic artery aneurysm. Our patient had not experienced any previous abdominal trauma, and GB hemorrhage was unlikely to result from cholecystitis or bleeding diathesis. A 55-year-old male was admitted because of right upper quadrant pain. Both prothrombin time and partial thromboplastin time were normal. Abdominal computed tomography, endoscopic ultrasound and magnetic resonance cholangiopancreatography were performed. Image studies revealed GB wall thickening and an intraluminal mass. Laparoscopic cholecystectomy was performed. Upon opening the GB postoperatively, a large amount of fresh blood and old blood clot was noted. The incidence of GB hematoma is very rare. GB hematoma should always be considered in the differential diagnosis of GB tumor. In such a situation, surgical intervention is needed for further patient evaluation and management. We present a rare case of intramural GB hematoma, of which we were unable to make a definitive diagnosis preoperatively