On Students' Strategy-Preferences for Managing Difficult Course Work

Course work plagiarism among university students is often attributed to ignorance about plagiarism or an assignment's level of difficulty. Students submit other people's work when they are unable to solve an assignment themselves. This study, based on 233 student responses from four cultural regions, investigates three aspects of academic dishonesty. First, the study identifies students' preferred strategies for managing perceptually too difficult course work. Second, students' preferences for responding to help from fellow students are investigated. Finally, the study measures students' preferences for choosing side in ethical conflicts. Seven strategies for managing difficult course work, six strategies for responding to requests for help, and five key parties in ethical conflicts are studied using a pair-wise comparison method. The results show that students prefer to collaborate and use the Internet. The impact of the teacher is smaller than expected. Factors including cultural origin, gender, level of study, and field of study have limited impact.     

Examination of the frequency modulation and lifting techniques for the generalized power factor correction switched‐capacitor resonant converter

A generalized method for switched‐capacitor resonant converter for use in power factor correction is proposed. Using the techniques, the voltage conversion can be generated into step‐up, step‐down and inverting. The requirement of the inductance in the circuit is minimal. The quality of the power factor improvement is substantial. The method used in the converter includes the frequency modulation and lifting techniques. The power factor improvement is significant and the circuit concept is simple. Mathematical analysis and experimental confirmation have been presented to demonstrate the novel idea. Copyright © 2007 John Wiley & Sons, Ltd.     

Dichloroacetate Radiosensitizes Hypoxic Breast Cancer Cells

Mitochondrial metabolism is an attractive target for cancer therapy. Reprogramming metabolic pathways can potentially sensitize tumors with limited treatment options, such as triple-negative breast cancer (TNBC), to chemo- and/or radiotherapy. Dichloroacetate (DCA) is a specific inhibitor of the pyruvate dehydrogenase kinase (PDK), which leads to enhanced reactive oxygen species (ROS) production. ROS are the primary effector molecules of radiation and an increase hereof will enhance the radioresponse. In this study, we evaluated the effects of DCA and radiotherapy on two TNBC cell lines, namely EMT6 and 4T1, under aerobic and hypoxic conditions. As expected, DCA treatment decreased phosphorylated pyruvate dehydrogenase (PDH) and lowered both extracellular acidification rate (ECAR) and lactate production. Remarkably, DCA treatment led to a significant increase in ROS production (up to 15-fold) in hypoxic cancer cells but not in aerobic cells. Consistently, DCA radiosensitized hypoxic tumor cells and 3D spheroids while leaving the intrinsic radiosensitivity of the tumor cells unchanged. Our results suggest that although described as an oxidative phosphorylation (OXPHOS)-promoting drug, DCA can also increase hypoxic radioresponses. This study therefore paves the way for the targeting of mitochondrial metabolism of hypoxic cancer cells, in particular to combat radioresistance.     

The investigation of the crystalline phases development in Macor® glass-ceramic

The commercially available, machinable, fluormica glass-ceramic, Macor^®, was remelted to produce a glass. This glass was then characterized by differential scanning calorimetry (DSC), combined differential thermal analysis/thermal gravimetric analysis (DTA/TGA), X-ray powder diffraction (XRD) and ¹⁹F magic angle spinning ?nuclear magnetic resonance (MAS-NMR). The Macor^® glass was shown to crystallize to chondrodite (Mg₅F₂(SiO₄)₂), followed by the conversion of chondrodite to norbergite (Mg₃SiO₄F₂) and the conversion of norbegite to a potassium fluorphlogopite phase (KMg₃AlSi₃O₁₀F₂). The glass exhibited an optimum nucleation temperature just above its glass transition temperature, which is indicative of a nucleation route involving amorphous phase separation. The ¹⁹F MAS-NMR spectra showed the fluorine environments being present as F-Mg(3) in the original glass, the chondrodite, norbergite and fluorphlogopite phases, indicating that the fluorine structure is conserved throughout the crystallization process. The activation energies for crystallization were found to be 215, 431 and 251 kJ mol^?1 for chondrodite, norbergite and fluorphlogopite, respectively.     

Crystallization behavior of polylactide matrix under the influence of nano‐magnetite

Iron oxide nanoparticle (Fe₃O₄) has gained remarkable research interest for various applications, from environmental to biological, because of its superparamagnetic properties and good biocompatibility. In this work, the nucleation effect of Fe₃O₄ in a polylactide (PLA) matrix under an influence of an alternating magnetic field was studied. The nanocomposite films that is, containing different concentrations of Fe₃O₄ (~8 nm) which were uniformly dispersed in the PLA matrix, were prepared via a solution casting method. The amplitude and frequency of the magnetic field impose great effects on the morphology and nucleation rate of PLA crystallization. Thermogravimetric analysis was used to study the thermal stability of Fe₃O₄/PLA and it showed that the thermal stability of Fe₃O₄/PLA was affected by the Fe₃O₄ content. Fourier transform infrared spectroscopy and X‐ray diffractometry indicated that Fe₃O₄ shows impeding effect to the crystallization of PLA. Based on the differential scanning calorimetry results, composite with 1% of Fe₃O₄ content could promote the crystallization of PLA but it would become an obstacle when 3% of Fe₃O₄ was added. The result of polarized optical microscopy also showed a good agreement that the incorporation of Fe₃O₄ could act as an effective nucleation regent to the composite film. POLYM. ENG. SCI., 59:608–615, 2019. © 2018 Society of Plastics Engineers     

Betacyanins extraction from Hylocereus polyrhizus using alcohol/salt-based liquid biphasic partitioning system and antioxidant activity evaluation

Betacyanins have gained increasing interest as natural food dye because of their health-promoting effects. This study investigated the betacyanins extraction from peel and flesh of red–purple pitaya using ethanol/K₂HPO₄-based liquid biphasic partitioning system (LBPS) by optimised concentrations of ethanol, K₂HPO₄, NaCl and crude. Overall, the highest values of betacyanins concentration in alcohol-rich top phase (C_t), phase volume ratio (V_r) and partition coefficient (K) of betacyanins that represented an optimum betacyanins extraction from the peel (98.080%, 1.667 and 51.097, respectively) and flesh (96.256%, 2.167 and 25.764, respectively) were achieved. Lastly, conventional solvent extractions, colour characterisation and antioxidant activity evaluation were conducted.     

房产交易与信息发布系统的开发及实现

综合考虑了一般房产管理的运行模式和现有的网络地理信息系统实现方法,在探索一个性能价格比高的房产交易与信息发布系统的实现方法的基础上,提出了一种基于Internet或Intranet上的房产交易管理信息系统模型模式;采用网络的主流技术ASP,同时结合ESRI公司的ArcIMS用SQLSERVER2000数据库实现房产交易管理和房产信息发布。