30 research outputs found

    The reliability inference for multicomponent stress–strength model under the Burr X distribution

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    DATA AVAILABILITY STATEMENT: Complete monthly water capacity data for the Shasta Reservoir from 1981 to 1985 are given in Appendix G. Section 6 includes the observed complete strength and stress data sets.The reliability of the multicomponent stress–strength system was investigated under the two-parameter Burr X distribution model. Based on the structure of the system, the type II censored sample of strength and random sample of stress were obtained for the study. The maximum likelihood estimators were established by utilizing the type II censored Burr X distributed strength and complete random stress data sets collected from the multicomponent system. Two related approximate confidence intervals were achieved by utilizing the delta method under the asymptotic normal distribution theory and parametric bootstrap procedure. Meanwhile, point and confidence interval estimators based on alternative generalized pivotal quantities were derived. Furthermore, a likelihood ratio test to infer the equality of both scalar parameters is provided. Finally, a practical example is provided for illustration.The National Science and Technology Council, the National Natural Science Foundation of China, the Yunnan Fundamental Research Projects, the Yunnan Key Laboratory of Modern Analytical Mathematics and Applications, the South Africa National Research Foundation and South Africa Medical Research Council.https://www.mdpi.com/journal/appliedmathStatisticsSDG-04:Quality EducationSDG-09: Industry, innovation and infrastructur

    Media 1: Candlelight LEDs fabricated by using composite silica photonic crystals

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    Originally published in Optical Materials Express on 01 February 2015 (ome-5-2-307

    Highly Reliable and Low-Cost Fabrication of Warm-White LEDs Using Composite Silica Photonic Crystals

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    We demonstrated a technique requiring little phosphor that used white light-emitting diodes (WLEDs) containing composite silica colloidal photonic crystals (c-SCPhCs) for developing the warm-WLEDs (w-WLEDs). WLEDs containing c-SCPhCs enhanced luminous efficacy 5.6% more than commercial w-WLEDs did. We used a UV adhesive curing method to improve the adhesion properties of the c-SCPhCs. A reliability analysis (RA) test was performed on the WLEDs containing c-SCPhCs, applying a high temperature and high relative humidity (85°C/85 RH) during WLEDs operation at 120 mA. During a RA test of 2500 h, no visible degradation in optical performance was observed. We implemented a novel, inexpensive technique for producing high luminous flux w-WLEDs that can be used in residential light

    The relationships between the medical learners’ motivations and strategies to learning medicine and learning outcomes

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    Background: One of the strongly theorized areas of research associated with learning outcomes has been the approaches to learning. Few studies have been focused on examining the relationship between the approaches to learning medicine (ALM) and learning outcomes. Objectives: The objectives were: (1) to conduct psychometric testing of the ALM questionnaire; and (2) to examine the association between medical learners’ ALM and learning outcomes. Design: We developed the ALM questionnaire which was a modification of the Revised Learning Process questionnaire. We defined the learning outcome of each house officer as the class rank in his/her graduating class. Exploratory factor analysis was used to examine the factor structure of the ALM questionnaire. We conducted Pearson’s and Spearman’s Rank correlation coefficients for examining the linear relationships between two continuous variables, and between a continuous variable and a categorical variable, respectively. Stepwise multivariate linear regression analysis with backward elimination was undertaken to examine the correlation between the ALM and the learning outcome. Results: A house officer with deep strategies (relating multiple ideas and truly understanding the course content) or surface motivations (aim for qualification) was more likely to have a better learning outcome as indicated by a better class rank based on his/her academic performance. Furthermore, a house officer with surface learning strategies (minimizing the study scope to merely passing the examination) to learning medicine was more likely to have an unfavorable class rank. Conclusions: This study represents the first report of the correlation between house officers’ ALM and learning outcomes. House officers with deep strategies were more likely to have better learning outcomes. In particular, house officers with a surface motive to learning medicine, i.e., aiming for qualification, were surprisingly correlated with better learning outcomes

    InGaN-based Light-Emitting Diodes with a Sawtooth-shaped Sidewall on Sapphire Substrate

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    An InGaN light emitting diode (LED) with a cone-shaped GaN structure and a sawtooth-shaped sapphire sidewall structure was fabricated through a laser-drilling process. The fabricated procedures consisted of a laser scribing/drilling process, a wet etching process, and a chip cleaving process. In the treated LED structure with the laser-drilling sawtooth-shaped sidewall, the light output power had a 16% enhancement compared to a conventional LED structure with a laser-scribing sidewall. A periodic high light emission intensity, with a 2.6ÎĽm-width spaced at regular intervals of 3.8ÎĽm, was observed on the treated LED sidewall structure corresponding to the laser-drilling patterns. The LED structure consists of a laser-drilling sidewall and a cone-shaped GaN structure that increases the light extraction efficiency for high efficiency InGaN LED applications

    GaN/AlGaN ultraviolet light-emitting diode with an embedded porous-AlGaN distributed Bragg reflector

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    A GaN/AlGaN-based ultraviolet light-emitting diode (LED) structure with an embedded porous-AlGaN reflector was fabricated by a doping-selective electrochemical (EC) wet-etching process. The n+-AlGaN/undoped-AlGaN (u-AlGaN) stack structures with different Al contents were transformed into porous-AlGaN/u-AlGaN stack structures that acted as the embedded distributed Bragg reflectors (DBRs). The porosity of the EC-treated AlGaN layer was increased by decreasing the Al content in the n+-AlGaN layer. The reflectivity of the porous-AlGaN DBR structure was measured to be 90% at 379.3 nm with a 37.2 nm stopband width. The photoluminescence emission intensity of the DBR-LED was enhanced by forming the embedded porous-AlGaN DBR structure

    Nanoparticulated Honokiol Mitigates Cisplatin-Induced Chronic Kidney Injury by Maintaining Mitochondria Antioxidant Capacity and Reducing Caspase 3-Associated Cellular Apoptosis

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    Cisplatin is a potent anti-cancer drug, however, its accompanied organ-toxicity hampers its clinical applications. Cisplatin-associated kidney injury is known to result from its accumulation in the renal tubule with excessive generation of reactive oxygen species. In this study, we encapsulated honokiol, a natural lipophilic polyphenol constituent extracted from Magnolia officinalis into nano-sized liposomes (nanosome honokiol) and examined the in vivo countering effects on cisplatin-induced renal injury. We observed that 5 mg/kg body weight. nanosome honokiol was the lowest effective dosage to efficiently restore renal functions of cisplatin-treated animals. The improvement is likely due the maintenance of cellular localization of cytochrome c and thus preserves mitochondria integrity and their redox activity, which as a consequence, reduced cellular oxidative stress and caspase 3-associated apoptosis. These improvements at the cellular level are later reflected on the observed reduction of kidney inflammation and fibrosis. In agreement with our earlier in vitro study showing protective effects of honokiol on kidney cell lines, we demonstrated further in the current study, that nanosuspension-formulated honokiol provides protective effects against cisplatin-induced chronic kidney damages in vivo. Our findings not only benefit cisplatin-receiving patients with reduced renal side effects, but also provide potential alternative and synergic solutions to improve clinical safety and efficacy of cisplatin treatment on cancer patients

    EGCG Inhibits Transforming Growth Factor-β-Mediated Epithelial-to-Mesenchymal Transition via the Inhibition of Smad2 and Erk1/2 Signaling Pathways in Nonsmall Cell Lung Cancer Cells

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    Transforming growth factor-β (TGF-β)-mediated epithelial mesenchymal transition (EMT) of human lung cancer cells may contribute to lung cancer metastasis. It has been reported that EGCG can inhibit tumorigenesis and cancer cell growth in lung cancer; however, the effect of EGCG on EMT in nonsmall cell lung cancer (NSCLC) cells has not been investigated. In this study, we found that NSCLC cells A549 and H1299 were converted to the fibroblastic phenotype in response to TGF-β. Epithelial marker E-cadherin was down-regulated, and mesenchymal marker vimentin was up-regulated simultaneously. Our results illustrated that TGF-β was able to induce EMT in NSCLC cells, and EGCG would reverse TGF-β-induced morphological changes, up-regulate the expression of E-cadherin, and down-regulate the expression of vimentin. Immunofluorescent staining also demonstrated that E-cadherin was up-regulated and that vimentin was down-regulated by EGCG pretreatment. Moreover, wound-healing and the in vitro invasion assay showed that EGCG could inhibit TGF-β-induced migration and invasion of NSCLC cells. By using the dual-luciferase reporter assay, we demonstrated that EGCG inhibited TGF-β-induced EMT at the transcriptional level. EGCG decreased the phosphorylation of Smad2 and Erk1/2, inhibited the nuclear translocation of Smad2, and repressed the expression of transcription factors ZEB1, Snail, Slug, and Twist, and up-regulated the expression of E-cadherin. In summary, our results suggest that EGCG can inhibit TGF-β-induced EMT via down-regulation of phosphorylated Smad2 and Erk1/2 in NSCLC cells
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