Thermal annealing of InGaN/GaN strained-layer quantum well

Quantum well (QW) material engineering has attracted a considerable amount of interest from many people because of its ability to produce a number of optoelectronic devices. QW composition intermixing is a thermal induced interdiffusion of the constituent atoms through the hetero-interface. The intermixing process is an attractive way to achieve the modification of the QW band structure. It is known that the band structure is a fundamental determinant for such electronic and optical properties of materials as the optical gain, the refractive index and the absorption. During the process, the as-grown square-QW compositional profile is modified to a graded profile, thereby altering the confinement profile and the subband structure in the QW. The blue-shifting of the wavelength in the intermixed QW structure is found in this process. In recent years, III-nitride semiconductors have attracted much attention. This is mainly due to their large bandgap range from 1.89eV (wurtzite InN) to 3.44eV (wurtzite GaN). InGaN/GaN quantum well structures have been used to achieve high lumens blue and green light emitting diodes. Such structures also facilitate the production of full colour LED displays by complementing the colour spectrum of available LEDs. In this paper, the effects of thermal annealing on the strained-layer InGaN/GaN QW will be presented. The effects of intermixing on the confinement potential of InGaN/GaN QWs have been theoretically analysed, with sublattices interdiffusion as the basis. This process is described by Fick's law, with constant diffusion coefficients in both the well and the barrier layers. The diffusion coefficients depend on the annealing temperature, time and the activation energy of constituent atoms. The optical properties of intermixed InGaN/GaN QW structure of different interdiffusion rates have been theoretically analyzed for applications of novel optical devices. The photoluminescence studies and the intermixed QW modeling have been used to understand the effects of intermixing.published_or_final_versio

High-resolution Raman microscopy of curled carbon nanotubes

The use of confocal Raman imaging spectroscopy and atomic force microscopy for identifying conditions of carbon nanotubes with bent nanotube bundles in the bent state was described. It was found that the tangential G mode on Raman spectra systemically shifts downward upon nanotube bending. The frequency shifts observed in the nanotubes were due to tensile strain of the bending nanotube arrays, which resulted in the loosening of C-C bonds in the outer walls. It was speculated that the frequency shift in Raman spectra was used for fast monitoring of the bending state of the standing carbon nanotube in gas and fluid flow nanosensors.open282

Correlation of PD-L1 Expression of Tumor Cells with Survival Outcomes after Radical Intensity-Modulated Radiation Therapy for Non-Metastatic Nasopharyngeal Carcinoma

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Experiential learning of HIV self-test among student nurses: A qualitative study

Background: There is increasing demand for HIV self-tests, and nurses play an important role in counselling and assisting in the testing process. Traditional lecture-based nursing education has not typically focused on self-testing procedures, and there is little understanding of clients' experiences of self-testing. Objectives: To understand the experiential learning (EL)of student nurses during the process of self-testing for HIV. Design: This study used a qualitative design. Settings: A college in northern Taiwan. Participants: We recruited a purposive sample of 30 nursing students. Methods: The OraQuick self-test was used as the self-testing tool in this study. After participants used the OraQuick self-test, they underwent a semi-structured interview during the post-test counselling period. All interview data were subjected to line-by-line content analysis. Results: We extracted nine themes of nursing students' experiences during experiential learning of HIV self-test. In the pre-test stage, they recalled possible risk behaviors for HIV infection, decided to complete the self-test alone or asked for significant others to accompany them, and endured emotional fluctuations immediately prior to the test. When waiting for the test results, they felt isolated from the outside world. Some participants also began questioning the accuracy and safety of the test, and either viewed the results immediately or later on. In the post-test stage, some participants reported being uncertain about the results. Participants reported a greater understanding of the personal impact of testing and revealed their needs for support. Some identified a sense of loss and linked this to the rapid and direct delivery of test results. Conclusions: Our results can be used to guide HIV-related education courses and prevention programs. Experiential learning has the potential to improve HIV pre and post-test counselling, as nurses develop both clinical knowledge and personal insight of the testing process

Capsular synovial metaplasia mimicking silicone leak of a breast prosthesis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Synovial metaplasia around a prosthesis and in particular around silicone breast implants has been noted by various investigators, but has unknown clinical significance. We report on a patient where a large amount of synovial fluid mimicked rupture of an implant. We believe this to be an unusual clinical presentation of this phenomenon. Review of the English language literature failed to identify a comparable case.</p> <p>Case presentation</p> <p>A 25-year-old woman had undergone bilateral breast augmentation for cosmetic reasons. One implant was subsequently subjected to two attempts at expansion to correct asymmetry. The patient was later found to have a large quantity of viscous fluid around the port of that same prosthesis. Histological assessment of the implant had consequently confirmed capsular synovial metaplasia. This had initially caused the suspicion of a silicone 'bleed' from the implant and had resulted in an unnecessary explantation.</p> <p>Conclusion</p> <p>Capsular synovial metaplasia should be ruled out before the removal of breast implants where a leak is suspected. Manipulation and expansion of an implant may be risk factors for the development of synovial metaplasia.</p

New plasma surface-treated memory alloys: Towards a new generation of "smart" orthopaedic materials

This paper describes the corrosion resistance, surface mechanical properties, cyto-compatibility, and in-vivo performance of plasma-treated and untreated NiTi samples. Nickel-titanium discs containing 50.8% Ni were treated by nitrogen and carbon plasma immersion ion implantation (PIII). After nitrogen plasma treatment, a layer of stable titanium nitride is formed on the NiTi surface. Titanium carbide is also found at the surface after carbon plasma implantation. Compared to the untreated samples, the corrosion resistances of the plasma PIII samples are better by a factor of five and the surface hardness and elastic modulus are better by a factor of two. The concentration of Ni leached into the simulated body fluids from the untreated samples is 30 ppm, whereas that from the plasma-treated PIII are undetectable. Although there is no significant difference in the ability of cells to grow on either surface, bone formation is found to be better on the nitrogen and carbon PIII sample surfaces at post-operation 2 weeks. All these improvements can be attributed to the formation of titanium nitride and titanium carbide on the surface. © 2007 Elsevier B.V. All rights reserved.postprin

Prognostication of serial post-intensity-modulated radiation therapy undetectable plasma EBV DNA for nasopharyngeal carcinoma

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Computable analysis of linear rearrangement optimization

Optimization problems over rearrangement classes arise in various areas such as mathematics, fluid mechanics, biology, and finance. When the generator of the rearrangement class is two-valued, they reduce to shape optimization and free boundary problems which can exhibit intriguing symmetry breaking phenomena. A robust framework is required for computable analysis of these problems. In this paper, as a first step towards such a robust framework, we provide oracle Turing machines that compute the distribution function, decreasing rearrangement, and linear rearrangement optimizers, with respect to functions that are continuous and have no significant flat zones. This assumption on the reference function is necessary, as otherwise, the aforementioned operations may not be computable. We prove that the results can be computed to within any degree of accuracy, conforming to the framework of Type-II Theory of Effectivity

Dkk4 and Eda Regulate Distinctive Developmental Mechanisms for Subtypes of Mouse Hair

The mouse hair coat comprises protective “primary” and thermo-regulatory “secondary” hairs. Primary hair formation is ectodysplasin (Eda) dependent, but it has been puzzling that Tabby (Eda-/y) mice still make secondary hair. We report that Dickkopf 4 (Dkk4), a Wnt antagonist, affects an auxiliary pathway for Eda-independent development of secondary hair. A Dkk4 transgene in wild-type mice had no effect on primary hair, but secondary hairs were severely malformed. Dkk4 action on secondary hair was further demonstrated when the transgene was introduced into Tabby mice: the usual secondary follicle induction was completely blocked. The Dkk4-regulated secondary hair pathway, like the Eda-dependent primary hair pathway, is further mediated by selective activation of Shh. The results thus reveal two complex molecular pathways that distinctly regulate subtype-based morphogenesis of hair follicles, and provide a resolution for the longstanding puzzle of hair formation in Tabby mice lacking Eda