166 research outputs found
Anti-tuberculosis host response modulation through immune cell targeting
Master'sMASTER OF SCIENC
Advances of endoscopic and surgical management in gastrointestinal stromal tumors
As one of the most common mesenchymal malignancies in the digestive system, gastrointestinal stromal tumors (GISTs) occur throughout the alimentary tract with diversified oncological characteristics. With the advent of the tyrosine kinase inhibitor era, the treatment regimens of patients with GISTs have been revolutionized and GISTs have become the paradigm of multidisciplinary therapy. However, surgery resection remains recognized as the potentially curative management for the radical resection and provided with favorable oncological outcomes. The existing available surgery algorithms in clinical practice primarily incorporate open procedure, and endoscopic and laparoscopic surgery together with combined operation techniques. The performance of various surgery methods often refers to the consideration of risk evaluation of recurrence and metastases; the degree of disease progression; size, location, and growth pattern of tumor; general conditions of selected patients; and indications and safety profile of various techniques. In the present review, we summarize the fundamental principle of surgery of GISTs based on risk assessment as well as tumor size, location, and degree of progress with an emphasis on the indications, strengths, and limitations of current surgery techniques
Genetic and environmental influence on foliar carbon isotope composition, nitrogen availability and fruit yield of 5-year-old mango plantation in tropical Australia
The aim of this study was to quantify the effect of different varieties, planting densities, tree training systems and canopy aspect (north and south) on tree water use efficiency and nitrogen (N) availability in relation to mango fruit yield and fruit size as well as soil fertility (particularly total carbon (C) and total N as well as C and N isotope compositions) in a 5-year-old mango plantation of tropical Australia
Issue of spatial coherence in MQW based micro-LED simulation
In existing flip-chip LED simulations, the light extraction efficiency is related to the multiple quantum well (MQW) to metal reflector distance because of optical interference. We calculate the contrast using several typical light intensity distributions among the several QWs in MQW. The coherence is obtained analytically. When the luminosity of each QW is equal, the contrast is ∼0, meaning the light is incoherent, contrary to traditional studies. The spatial coherence is important only when the light emission comes from just one QW. As the MQW has a not negligible thickness, the traditional single-dipole model is no longer accurate
GaN LEDs with in situ synthesized transparent graphene heat-spreading electrodes fabricated by PECVD and penetration etching
Currently, applying graphene on GaN based electronic devices requires the troublesome, manual, lengthy, and irreproducible graphene transfer procedures, making it infeasible for real applications. Here, a semiconductor industry compatible technique for the in situ growth of patterned graphene directly onto GaN LED epiwafers for transparent heat-spreading electrode application is introduced. Pre-patterned sacrificial Co acts as both an etching mask for the GaN mesa and a catalyst for graphene growth. The Co helps in catalyzing the hydrocarbon decomposition and the subsequent graphitization, and is removed by wet etching afterwards. The use of plasma enhancement in the graphene chemical vapor deposition reduces the growth temperature to as low as 600 °C and improves the graphene quality, where highly crystalline graphene can be obtained in just 2 min of deposition. This method reduces the exposure of the GaN epilayers to high temperature to its limit, avoiding the well-known GaN decomposition and In segregation problems. Importantly, it can directly pattern the graphene without using additional lithographic steps and in doing so avoids any unintentional deleterious doping and damage of graphene from contact with the photoresist. The approach simplifies the fabrication and enables mass production by eliminating the bottlenecks of graphene transfer and patterning procedures. By comparing the GaN LEDs with and without graphene, we find that graphene greatly improves the device optical, electrical and thermal performances, due to the high optical transparency (91.74%) and high heat spreading capability of the graphene electrode. Unlike transferred graphene, this method is intrinsically scalable, reproducible, and compatible with the planar process, and is beneficial to the industrialization of GaN-graphene optoelectronic devices, where the integrated graphene serves as a superior sustainable and functional substitute to other transparent conducting materials such as ITO.<br/
Simultaneous removal of Cr(VI) and 4-chlorophenol through photocatalysis by a novel anatase/titanate nanosheet composite: Synergetic promotion effect and autosynchronous doping
Clean-up of wastewaters with coexisting heavy metals and organic contaminants is a huge issue worldwide. In this study, a novel anatase/titanate nanosheet composite material (labeled as TNS) synthesized through a one-step hydrothermal reaction was demonstrated to achieve the goal of simultaneous removal of Cr(VI) and 4-cholophenol (4-CP) from water. TEM and XRD analyses indicated the TNS was a nano-composite of anatase and titanate, with anatase acting as the primary photocatalysis center and titanate as the main adsorption site. Enhanced photocatalytic removal of co-existent Cr(VI) and 4-CP was observed in binary systems, with apparent rate constants (k(1)) for photocatalytic reactions of Cr(VI) and 4-CP about 3.1 and 2.6 times of that for single systems. In addition, over 99% of Cr(VI) and 4-CP was removed within 120 min through photocatalysis by TNS at pH 7 in the binary system. Mechanisms for enhanced photocatalytic efficiency in the binary system are identified as: (1) a synergetic effect on the photo-reduction of Cr(VI) and photo-oxidation of 4-CP due to efficient separation of electron-hole pairs, and (2) autosynchronous doping because of reduced Cr(III) adsorption onto TNS. Furthermore, TNS could be efficiently reused after a simple acid-base treatment. (C) 2016 Elsevier B.V. All rights reserved.National Natural Science Foundation of China [51508006]; Natural Science Foundation of the Colleges and Universities in Jiangsu Province [15KJB610011]SCI(E)[email protected]; [email protected]
Transfer-free, lithography-free and fast growth of patterned CVD graphene directly on insulators by using sacrificial metal catalyst
Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts
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