Temperature Dependent Current-voltage Characteristics of P-type Crystalline Silicon Solar Cells Fabricated Using Screen-printing Process

We have fabricated p-type crystalline silicon (Si) solar cells using screen-printing process and investigated their electrical properties. Ph screen printing process led to the uniform formation of n+ emitter. As a result of interaction between Ph-dopant paste and Si substrate, a phosphosilicate glass layer was formed on n+ emitter surface. The current-voltage characteristics were carried out in the temperature range of 175 – 450 K in steps of 25 K. The variation in current level at a particular voltage strongly depended on temperature, indicating that the current transport across the junction was a temperature activated process. The reverse leakage current gradually increased with increasing measurement temperature up to 350 K, above which it rapidly increased. Arrhenius plot of the leakage current revealed that reverse leakage current in low and high temperature regions were dominated by the tunneling mechanism, and generation and recombination mechanism, respectively. Keywords: P-type Si solar cell, screen-printing, I-V, tunneling, generation and recombination, reverse leakage curren

Increased expression of cysteine cathepsins in ovarian tissue from chickens with ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Cysteine cathepsins (CTSs) are involved in the degradation and remodeling of the extracellular matrix and are associated with cell transformation, differentiation, motility, and adhesion. These functions are also related to cancer cell invasion and metastasis. Chickens spontaneously develop epithelial ovarian cancer and are therefore a good animal model for human ovarian cancer. However, no studies have investigated the expression of CTSs in chickens with ovarian cancer.</p> <p>Methods</p> <p>Cancerous (n = 5) and normal (n = 3) ovaries were collected from 2-to 3-year-old hens, and ovarian tissue samples were collected for study. Ovarian cancers were evaluated with hematoxylin and eosin staining. Reverse transcriptase and quantitative PCR analyses, in situ hybridization analysis were performed to examine the mRNA expression pattern of three CTSs in detail, and protein expression of CTSB was evaluated.</p> <p>Results</p> <p>The CTSB, CTSC, and CTSS genes were highly expressed in cancerous chicken ovaries. Messenger RNAs for the three CTSs were localized to a nodule area, a major characteristic of cancerous ovaries, but the three CTSs showed no specific localization in normal ovaries. Immunoreactive CTSB protein was present in the nodule area of cancerous ovaries.</p> <p>Conclusion</p> <p>Our results suggest that CTSB, CTSC, and CTSS have important functions in the development of epithelial ovarian cancer.</p

The involvement of AMPK/GSK3-beta signals in the control of metastasis and proliferation in hepato-carcinoma cells treated with anthocyanins extracted from Korea wild berry Meoru

BACKGROUND: Activation of the Wnt pathway is known to promote tumorigenesis and tumor metastasis, and targeting Wnt pathway inhibition has emerged as an attractive approach for controlling tumor invasion and metastasis. The major pathway for inhibiting Wnt is through the degradation of β-catenin by the GSK3-beta/CK1/Axin/APC complex. It was found that Hep3B hepato-carcinoma cells respond to anthocyanins through GSK3-beta-induced suppression of beta-catenin; however, they cannot dephosphorylate GSK3-beta without AMPK activation. METHODS: We tested the effects of anthocyanins on proliferation and apoptosis by MTT and Annexin V-PI staining in vitro. Mouse xenograft models of hepato-carcinomas were established by inoculation with Hep3B cells, and mice were injected with 50 mg/kg/ml of anthocyanins. In addition, protein levels of p-GSK3-beta, beta-catenin, p-AMPK, MMP-9, VEGF, and Ang-1 were also analyzed using western blot. RESULTS: Anthocyanins decrease phospho-GSK3-beta and beta-catenin expression in an in vivo tumor xenograft model, increase AMPK activity in this model, and inhibit cell migration and invasion, possibly by inhibiting MMP-2 (in vitro) and the panendothelial marker, CD31 (in vivo). To elucidate the role of the GSK3-beta/beta-catenin pathway in cancer control, we conditionally inactivated this pathway, using activated AMPK for inhibition. Further, we showed that AMPK siRNA treatment abrogated the ability of anthocyanins to control cell proliferation and metastatic potential, and Compound C, an AMPK inhibitor, could not restore GSK3-beta regulation, as exhibited by anthocyanins in Hep3B cells. CONCLUSION: These observations imply that the AMPK-mediated GSK3-beta/beta-catenin circuit plays crucial roles in inhibiting cancer cell proliferation and metastasis in anthocyanin-treated hepato-carcinoma cells of Meoru origin

Prevalence of Enterobius vermicularis among Preschool Children in Gimhae-si, Gyeongsangnam-do, Korea

The present study was performed to determine the prevalence of Enterobius vermicularis among preschool children in Gimhae-si, Korea. A total of 6,921 preschool children in 76 kindergartens were examined using the cellotape perianal swab method. The overall egg positive rate (EPR) was 10.5%. The EPR in boys was higher than that in girls (adjusted odds ratio [AOR]: 1.5, P<0.001), and it was higher in rural than in urban children (AOR: 1.2, P=0.022). The present study confirmed that the prevalence of E. vermicularis infection is fairly high among preschool children in Gimhae-si. Therefore, systematic control and preventive measures should be adopted to reduce morbidity associated with this nematode infection

Treatment of Spontaneous Cervical Spinal Subdural Hematoma with Methylprednisolone Pulse Therapy

We report herein a case of hyperacute onset of spontaneous cervical spinal subdural hematoma treated with methylprednisolone pulse therapy that showed good results. A 57-year-old man was admitted for posterior neck pain and paraparesis which occurred an hour ago. MRI revealed a ventral subdural hematoma distributed from the level of C1 down to T3, compressing the spinal cord. Conservative management with methylprednisolone pulse therapy was administered considering the patient's poor general condition. Although emergent surgical decompression is necessary in most cases of spinal subdural hematoma, conservative management with steroid therapy could be effective