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The generation and evolution of defects in 4H-SiC p-n junctions due to carrier injection under forward bias have been investigated by synchrotron white beam x-ray topography, electroluminescence imaging, and KOH etching. The defects are Shockley stacking faults with rhombic or triangular shapes bound by partial dislocation loops with dislocation lines along Peierls valleys (〈11-20&〉) or along the intersection of the basal plane containing the fault and diode surface. The Burgers vector of all bounding partials was of 1/3〈10-10〉-type. Among six possible types of partial dislocations with these properties, only two were observed in the volume of the epitaxial structure. One was tentatively identified as 30° carbon-core [C(g)30°] and second as 30° silicon-core [ Si(g) 30°] partial dislocation. Only one of them [proposed to be the Si(g) 30° partial] have been observed to move and emit light under forward bias. The other type of bounding dislocation [C(g) 30°] remained stationary during current injection. Low angle grain boundaries have been observed to act as one of a number of possible nucleation sites of stacking faults. [ABSTRACT FROM AUTHOR]

The structural defects in sublimation-grown silicon carbide layers have been investigated by transmission electron microscopy, atomic force microscopy, x-ray topography, and KOH etching. Nucleation of two-dimensional islands on damage free surfaces of high quality Lely seeds led to formation of stacking faults at the initial stages of growth. The location and number of stacking faults correlates with threading dislocation density. Also, the growth rate is shown to have a pronounced effect on the threading dislocation densities. Elementary screw dislocation density has been observed to increase from 20 cm[sup -2] to 4×10[sup 3] cm[sup -2] for growth rates increasing from 0.02 to 1.5 mm/h. Growth on seeds miscut 5° off the c axis resulted in screw dislocation densities almost two orders of magnitude lower than on axis growth. The results are interpreted as due to SiC stacking disorder at the initial stages of growth. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In sheet metal processing and manufacturing, there are a lot of small- and medium-sized job shops. These small- and medium-sized manufacturing companies have been facing keen competitive pressure in the market. This pressure has forced these companies to make every effort to shorten product development lead-time, improve production efficiency, approach high-quality standards, but at the same time cut down the costs. To meet the needs of these companies, this paper presents a compound cutting and punching production method supported by an integrated CAD/CAPP/CAM system in sheet metal manufacturing. Many existing commercial CAD/CAM systems are not suitable for this manufacturing method, especially under concurrent and global design and manufacturing environments. Some problems have to be solved before these CAD/CAM systems can be employed and integrated for this compound manufacturing method. This paper deals mainly with the solutions to solve some of these problems. The solutions include an integrated data integration platform based on Pro/INTRALINK and STEP, and a knowledge-based real time CAPP (RTCAPP) system for compound sheet metal cutting and punching. Within the presented CAD/CAPP/CAM system, some key modules have been developed. They are the automatic tool selection and manufacturing sequencing module, a shortest tool path optimization module, a cost estimation module and an automatic insertion of auxiliary path module based on knowledge bases. These modules will be addressed here. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To study the effect of RBMS3 on nucleus pulposus cells and its effect on the Wnt/ß-catenin signaling pathway. PATIENTS AND METHODS: We measured the expression of RBMS3 in human nucleus pulposus tissues with different degrees of degeneration. Recombinant human IL-1ß is used to stimulate the degeneration of human nucleus pulposus cells. We used Wnt/ß-catenin signaling pathway inhibitors and cell transfection to study the effect of RBMS3 on nucleus pulposus cells and its mechanism. RESULTS: RBMS3 was less expressed in the nucleus pulposus tissue of people with higher degeneration degree. IL-1ß reduced the expression of RBMS3 in nucleus pulposus cells. Overexpression of RBMS3 can promote the proliferation of nucleus pulposus cells and reduce the apoptosis and inflammation of cells. In addition, RBMS3 can reduce the expression of ß-catenin and c-myc in nucleus pulposus cells, and inhibit the activity of the Wnt/ß-catenin signaling pathway. CONCLUSIONS: RBMS3 inhibits the Wnt/ß-catenin signaling pathway, improves the proliferation ability of nucleus pulposus cells, inhibits their apoptosis and inflammation, and thus delays the degeneration of the intervertebral disc. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Multiple sclerosis (MS) has affected over 2 million people worldwide and it is thought to be initiated by the activated central nervous system (CNS). Reactive CD4+ T cells (TH1, TH17, and Treg phenotypes) are crucial to MS. The TH1 phenotype can promote major histocompatibility complex-II expression and TH17 can induce inflammatory gene expression. Curcumin, a yellow pigment, is found in turmeric rhizomes and has been reported to have various activities, such as anti-proliferative and anti-inflammatory activity. Curcumin has great potential in MS treatment. Little is known about the effect of curcumin on MS. Therefore, we investigated the effect of curcumin on MS, especially on CD4+ T cells. MATERIALS AND METHODS: CD4+ T cells (TH1, TH17, and Treg cells) were cultured in Iscove's Modified Dulbecco's Medium (IMDM) medium. Cell proliferation was evaluated by MTT assay. The ability of individual CD4+ T cells to aggregate into viable colony clusters was assessed by clonogenic survival assay. Apoptosis of CD4+ T cells was determined by flow cytometry. The expression of Bcl-2, Bax, and active caspase-3 was detected by Western blotting. The effect of curcumin on the activation molecule was also evaluated by flow cytometry. RESULTS: M TT a ssay s howed t hat c urcumin significantly inhibited CD4+ T cell viability. Furthermore, TH1, TH17, and Treg all showed a dose-dependent but not time-dependent. The results of clonogenic survival assay revealed that curcumin markedly decreased the colony formation ability of CD4+ T cells. Flow cytometry results indicated that curcumin-induced remarkable apoptosis in TH1, TH17, and Treg cells. After treatment with curcumin, the expression of Bcl-2 was decreased and that of Bax and active caspase-3 was increased. Western blotting results also showed that curcumin-induced apoptosis in CD4+ T cells. Hence, our results demonstrated that curcumin inhibited CD4+ T cell proliferation via inducing apoptosis in CD4+ T cells. Meanwhile, flow cytometry results also showed that curcumin directly inhibited CD4+ T cell activation. CONCLUSIONS: Curcumin could inhibit CD4+ T cell proliferation and effector cell activation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the relationship between the expression of sodium/ iodide transporter (NIS) and thyroid stimulating hormone receptor (TSHR) and iodine nutritional status in patients with thyroid carcinoma. PATIENTS AND METHODS: 146 cases of thyroid cancer in Shanghai Gongli Hospital, the Second Military Medical University between February and December 2014 were selected as thyroid cancer group, 120 cases of normal thyroid morphology examined by thyroid ultrasound at the same period were selected as normal group. General information and thyroid function of two groups were recorded and analyzed. H&E staining was used to perform histopathological study on both normal group and thyroid cancer group, and immunohistochemistry was used to detect NIS and TSHR protein expression and position. Reverse transcriptase polymerase chain reaction (RT-PCR) was used for quantitative detection of NIS and TSHR mRNA in the two groups, and the relationship between iodine nutrition and NIS and TSHR expression in thyroid cancer patients was studied. The expression of NIS and TSHR in each group was detected by Western blotting, and the difference in NIS and TSHR expression was analyzed by SPSS 17.0 statistical software. RESULTS: The difference of serum total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH) levels between the normal group and the thyroid cancer group was statistically significant (p < 0.05). H&E staining showed that the histopathology of the thyroid cancer group was significantly different from that of the normal group. Immunohistochemistry showed the positive expression of NIS and TSHR in thyroid cancer group. The expression of NIS and TSHR mRNA and protein in thyroid cancer patients was significantly lower than that in normal group detected by RTPCR and Western blotting. Analysis of variance showed that the difference of NIS and TSHR expression between the two groups was statistically significant (p < 0.05). CONCLUSIONS: These findings indicated that the expression of NIS and TSHR in thyroid cancer is closely related to iodine nutritional status, which has important research value. [ABSTRACT FROM AUTHOR]