326 research outputs found

    Challenges Experienced by Korean Medical Students and Tutors During Problem-Based Learning: A Cultural Perspective

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    How people learn is influenced by the cultural contexts in which their learning occurs. This qualitative case study explored challenges Korean medical students and tutors experienced during their PBL sessions from a cultural perspective using Hofstede’s cultural dimensions. Twelve preclinical medical students and nine tutors from a large Korean medical school participated in interviews. The interview data were analyzed using the constant comparative method and classified according to Hofstede’s cultural dimensions. Twenty-two themes emerged within the following overarching categories: large power distance (6 themes), high uncertainty avoidance (6), individualism (3), collectivism (4), and masculinity/short-term orientation (3). This article discusses culturally responsive solutions with regard to each cultural dimension, which would help overcome these challenges and enhance the experiences of students and tutors with PBL

    Hu.4-1BB-Fc fusion protein inhibits allergic inflammation and airway hyperresponsiveness in a murine model of asthma

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    Purpose4-1BB (CD 137) is a costimulatory molecule expressed on activated T-cells. Repression by 4-1BB is thought to attenuate Th2-mediated allergic reactions. The aim of this study was to investigate the effect of 4-1BB on allergic airway inflammation in a murine asthma model.MethodsBALB/c mice were sensitized to and challenged with ovalbumin (OVA). Hu.4-1BB-Fc was administered 1 day before the first OVA sensitization or 1 day after the second OVA sensitization. Following antigen challenge, airway responsiveness to methacholine was assessed and bronchoalveolar lavage (BAL) fluid was analyzed. Total immunoglobulin (Ig) E, OVA-specific IgE, IgG1, and IgG2a levels in sera were measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated.ResultsIn mice treated with Hu.4-1BB-Fc before the first OVA sensitization, there was a marked decrease in airway hyperresponsiveness, total cell count, and eosinophil count in the BAL fluid. In addition, Hu.4-1BB-Fc treatment decreased serum OVA-specific IgG1 levels and increased serum IgG2a level significantly compared with the corresponding levels in mice sensitized to and challenged with OVA. Hu.4-1BB-Fc-treated mice also showed suppressed peribronchial and perivascular inflammatory cell infiltration. In contrast, treatment with Hu.4-1BB-Fc 1 day after sensitization had no effect on airway hyperresponsiveness and showed less suppression of inflammation in lung tissue.ConclusionAdministration of Hu.4-1BB-Fc can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. In addition, administration before sensitization may be more effective. These findings suggest that 4-1BB may be a useful therapeutic molecule against asthma

    Nonlinear Optical Properties Of GeSbS Chalcogenide Waveguides

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    We characterize the nonlinear optical properties of GeSbS chalcogenide glasses with fiber-based experiments. A waveguide nonlinear parameter of 7 W-1/m and nonlinear refractive index of 3.71 x 10-18 m2/W are estimated by self-phase modulation. A GeSbS waveguide could also generate a supercontinuum from 1280 to 2120 nm at the -30 dB level for maximum coupled power of 340 W, showing a 14-fold spectral broadening of the input spectrum explained by cascaded stimulated Raman scattering

    Nonlinear characterization of GeSbS chalcogenide glass waveguides

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    GeSbS ridge waveguides have recently been demonstrated as a promising mid – infrared platform for integrated waveguide – based chemical sensing and photodetection. To date, their nonlinear optical properties remain relatively unexplored. In this paper, we characterize the nonlinear optical properties of GeSbS glasses, and show negligible nonlinear losses at 1.55 μm. Using self – phase modulation experiments, we characterize a waveguide nonlinear parameter of 7 W[subscript −1]/m and nonlinear refractive index of 3.71 × 10[superscript −18] m[superscript 2]/W. GeSbS waveguides are used to generate supercontinuum from 1280 nm to 2120 nm at the −30 dB level. The spectrum expands along the red shifted side of the spectrum faster than on the blue shifted side, facilitated by cascaded stimulated Raman scattering arising from the large Raman gain of chalcogenides. Fourier transform infrared spectroscopic measurements show that these glasses are optically transparent up to 25 μm, making them useful for short – wave to long – wave infrared applications in both linear and nonlinear optics.SUTD-MIT International Design Centre (IDC

    Chemo-resistant choriocarcinoma metastatic to colon cured by low-anterior resection

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    The role of surgery in the treatment of patients with metastatic choriocarcinoma has diminished. We present a case of chemo-resistant metastatic choriocarcinoma salvaged by surgery. A 48-year-old patient presented with uterine perforation and severe intractable hemorrhage, and histological examination revealed a choriocarcinoma. After 6 years of disease-free state, recurrence occurred in the rectosigmoid colon. Seven cycles of EMACO chemotherapy was administered, and the human chorionic gonadotropin level was normalized. Three months after the chemotherapy, the rectosigmoid colon metastasis progressed. Low anterior resection with lymphadenectomy up to the level of the inferior mesenteric artery was conducted. After the operation, the human chorionic gonadotropin level decreased to within the normal range. There has been no evidence of disease for 13 months since the operation. Local resection of metastases seems to play a significant role in curing the disease in a small subset of patients

    OCT for non-destructive examination of the internal biological structures of mosquito specimen

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    The Study of mosquitoes and their behavioral analysis are of crucial importance to control the alarmingly increasing mosquito-borne diseases. Conventional imaging techniques use either dissection, exogenous contrast agents. Non-destructive imaging techniques, like x-ray and microcomputed tomography uses ionizing radiations. Hence, a non-destructive and real-time imaging technique which can obtain high resolution images to study the anatomical features of mosquito specimen can greatly aid researchers for mosquito studies. In this study, the three-dimensional imaging capabilities of optical coherence tomography (OCT) for structural analysis of Anopheles sinensis mosquitoes has been demonstrated. The anatomical features of An. sinensis head, thorax, and abdomen regions along with internal morphological structures like foregut, midgut, and hindgut were studied using OCT imaging. Two-dimensional (2D) and three-dimensional (3D) OCT images along with histology images were helpful for the anatomical analysis of the mosquito specimens. From the concurred results and by exhibiting this as an initial study, the applicability of OCT in future entomological researches related to mosquitoes and changes in its anatomical structure is demonstrated
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