Differential Cytotoxicity Mechanisms of Copper Complexed with Disulfiram in Oral Cancer Cells

Disulfiram (DSF), an irreversible aldehyde dehydrogenase inhibitor, is being used in anticancer therapy, as its effects in humans are known and less adverse than conventional chemotherapy. We explored the potential mechanism behind the cytotoxicity of DSF-Cu⁺/Cu²⁺ complexes in oral epidermoid carcinoma meng-1 (OECM-1) and human gingival epithelial Smulow-Glickman (SG) cells. Exposure to CuCl₂ or CuCl slightly but concentration-dependently decreased cell viability, while DSF-Cu⁺/Cu²⁺ induced cell death in OECM-1 cells, but not SG cells. DSF-Cu⁺/Cu²⁺ also increased the subG1 population and decreased the G1, S, and G2/M populations in OECM-1 cells, but not SG cells, and suppressed cell proliferation in both OECM-1 and SG cells. ALDH enzyme activity was inhibited by CuCl and DSF-Cu⁺/Cu²⁺ in SG cells, but not OECM-1 cells. ROS levels and cellular senescence were increased in DSF-Cu⁺/Cu²⁺-treated OECM-1 cells, whereas they were suppressed in SG cells. DSF-Cu⁺/Cu²⁺ induced mitochondrial fission in OECM-1 cells and reduced mitochondrial membrane potential. CuCl₂ increased but DSF- Cu²⁺ impaired oxygen consumption rates and extracellular acidification rates in OECM-1 cells. CuCl₂ stabilized HIF-1α expression under normoxia in OECM-1 cells, and complex with DSF enhanced that effect. Levels of c-Myc protein and its phosphorylation at Tyr58 and Ser62 were increased, while levels of the N-terminal truncated form (Myc-nick) were decreased in DSF-Cu⁺/Cu²-treated OECM-1 cells. These effects were all suppressed by pretreatment with the ROS scavenger NAC. Overexpression of c-Myc failed to induce HIF-1α expression. These findings provide novel insight into the potential application of DSF-CuCl₂ complex as a repurposed agent for OSCC cancer therapy.     

Diffusion Behavior of Zn During Reflow of Sn-9Zn Solder on Ni/Cu Substrate

Reflow behavior of Sn-Zn solder on Ni/Cu substrate was investigated in an infrared (IR) reflow furnace using different heating rates from 180 °C/min to 36 °C/min. Energy dispersive spectroscopy (EDX) studies of the reflowed samples showed increased diffusion of Zn from the solder to the intermetallic compound (IMC) layer with a decrease in heating rate. Higher interfacial activity and affinity of the Zn in the formation of the IMC with the lowering of the heating rate were further demonstrated by electron probe microanalyzer (EPMA) results. The Zn diffusion behavior was related to its higher reactivity and smaller size in comparison with Sn, phase separation during heating, and affinity of Zn to form Ni-Sn-Zn and Ni-Zn intermetallic compounds.     

Internet function and Internet addictive behavior

Ju [Research on personal characteristics, the behavior of using Internet and Internet addiction for Taiwanese college study. Master thesis. Taiwan, 2000] found the Internet function was related to the severity of Internet addiction, and this study explored the relationship between the Internet function and the Internet addictive behavior. Seventy-six college students were included in this study and had completed the Internet use function questionnaire (social function, informational function, leisure function and the virtual emotional function) and the Chinese Internet Addiction Scale (compulsive use, withdrawal, tolerance, time management problem and interpersonal and health problems). The study revealed not only the relationship between the social function and the index of the Internet dependence (compulsive use, withdrawal, tolerance and the problems in the interpersonal relationship and health), but also the correlation between the information function and the index of the Internet abuse (the problems in the interpersonal relationship and health). We found the social function played the core role in the Internet addictive behavior and the mechanism needs further discussion.     

A study of Facebook Groups members’ knowledge sharing

There have been many studies focusing on individuals’ knowledge sharing behavior in the organizational setting. With the rapid prevalence of social networking sites, many people began to express their thoughts or share their knowledge via Facebook website. Facebook is an open environment which does not provide any immediate monetary benefits to its users. Its Groups members’ knowledge sharing behavior could be different from the ones in organizations. We proposed a research model to examine factors which promote the Facebook Groups users’ willingness to share knowledge. The factors in the study include extrinsic motivation, social and psychological forces, and social networking sharing culture. We used PLS to test our proposed hypotheses based on 271 responses collected through an online survey. Our results indicated that reputation would affect knowledge sharing attitude of Groups members and sense of self-worth would directly and indirectly (through subjective norm) affect the attitude. In addition, social networking sharing culture (fairness, identification, and openness) is the most significant factor, not only directly affecting knowledge sharing intention, but also indirectly influencing the sharing intention through subjective norm and knowledge sharing attitude.     

Biodiesel production from supercritical carbon dioxide extracted Jatropha oil using subcritical hydrolysis and supercritical methylation

This study investigates supercritical carbon dioxide (SC-CO₂) extraction of triglycerides from powdered Jatropha curcas kernels followed by subcritical hydrolysis and supercritical methylation of the extracted SC-CO₂ oil to obtain a 98.5% purity level of biodiesel. Effects of the reaction temperature, the reaction time and the solvent to feed ratio on free fatty acids in the hydrolyzed oil and fatty acid esters in the methylated oil via two experimental designs were also examined. Supercritical methylation of the hydrolyzed oil following subcritical hydrolysis of the SC-CO₂ extract yielded a methylation reaction conversion of 99%. The activation energy of hydrolysis and trans-esterified reactions were 68.5 and 45.2 kJ/mole, respectively. This study demonstrates that supercritical methylation preceded by subcritical hydrolysis of the SC-CO₂ oil is a feasible two-step process in producing biodiesel from powdered Jatropha kernels.     

An accuracy improvement for balancing crankshafts

Due to measurement errors, the final accuracy of rotor balancing may not be satisfied. This study is based on a modified influence coefficient method associated with multi-plane technique for the improvement of accuracy in balancing crankshafts. This method extends the conventional influence coefficient method, in which two trial masses in one balancing plane are employed, to one utilizing three trial masses in one plane. On the basis of three trial runs, the balancing accuracy can then be improved by the optimization of influence coefficient matrices resulting from the minimization of measurement errors. The feasibility of this modified approach is carried out by the verification of accuracy improvement in experiments, balancing two crankshafts.     

Optimal parameter design for chip-on-film technology using the Taguchi method

Chip on film (COF) is a new technology aggressively developed by liquid crystal display (LCD) module manufacturers. COF is a potential replacement method for tape-automated bonding (TAB) and chip-on-glass (COG) technology. COF technology has the following advantages: low power consumption, low cost, small structure, light weight and high resolution. It has become the major LCD module application. However, COF technology has several nonconforming items that should be reduced. These items include bonding misalignment, insufficient bonding strength and surface mount technology (SMT), solder joint defects, etc. The purpose of this study is to determine the optimum process parameters for COF technology improvement. An L₁₈ orthogonal array is employed to conduct the design of experiment for finding the optimum process parameters. The results show that bonding misalignment is reduced and bonding strength increased .     

Improving bonding strength of tape-automated bonding technology by implementing statistical process control: a case study

The purpose of this paper is to improve the bonding strength of tape-automated bonding (TAB) technology in supertwisted nematic liquid crystal display (STN LCD) module manufacturing by double-process control. First, the quality characteristic – the output of the process – is monitored by control charts and the variation of the process is reduced. Later, it is found that the quality characteristic is affected by critical input process parameters. These critical input process parameters and the quality characteristic are therefore monitored simultaneously. By this double-process control, the deviation of the process is further reduced. The results show that process capability and yield rate are increased.     

Temperature transients in flowing boreholes

We consider the problem of temperature transients in a borehole which has been drilled into an isothermal homogeneous solid and which is flowing at a constant rate. At a fixed time, the temperature of the fluid entering the borehole at the bottom is raised by a given amount. We derive the theoretical expression for the temperature response of the borehole and give a few numerical data of practical value.