Enhanced detection of phosphopeptides in matrix-assisted laser desorption/ionization mass spectrometry using ammonium salts

The hydrolytic degradation of poly(DL-lactide) (PLA50) material was investigated in order to elucidate the effects of temperature and acidity of the external medium on the degradation characteristics. It was observed that at 60 degrees C and at pH = 7.4, degradation was extremely rapid as compared with degradation at 37 degrees C. After only 2 days, heterogeneous degradation was observed due to larger internal autocatalysis. On the other hand, in the case of degradation at 37 degrees C in an acidic medium with pH = 3.7, the heterogeneous degradation was preceded by a much longer lag time. Water absorption was found to be pH dependent. At pH = 7.4, water absorption was increased due to the osmotic pressure driving the buffer solution into the polymer matrix to neutralize acidic endgroups, which was not the case for degradation at pH = 3.7. In both cases, the oligomeric stereocomplex was obtained as degradation residue at the end of the degradation period.     

Assessing realized information systems strategy

This research developed and validated a tool to measure realized information systems strategy or existing uses of information technology in organizations. It was recognized that intended uses of technology often differ from actual uses. The objective of the study was to determine a valid and reliable way of quantifying how information technology is actually used by organizations to provide support for business operations.     

A parametric study of the large scale production of multi-walled carbon nanotubes by fluidized bed catalytic chemical vapor deposition

A parametric study investigating the impact of temperature, run duration, total pressure, and composition of the gaseous phase on the catalytic growth of multi-walled carbon nanotubes (MWCNT) has been performed. MWCNTs have been produced very selectively on the multi-gram scale by catalytic chemical vapor deposition from ethylene in a fluidized bed reactor. The kinetics of MWCNTs growth is fast and, with the catalyst used, no induction period has been observed. The kinetic law is of positive order in ethylene concentration and the process is limited by internal diffusion in the porosity of the catalyst. The formation of MWCNTs in the macroporosity of the catalyst induces an explosion of the catalyst grains. Such a process, thanks to the absence of temperature gradient and to the efficient mixing of the grains allows a uniform and selective treatment of the catalyst powder leading to very high selectivity towards MWCNTs formation. High purity MWCNTs have been obtained after catalyst dissolution. Depending on the temperature of production, the specific surface area of this material ranged between 95 and 455 m²/g.     

Modeling of Ethylene Glycol Production from Glucose in a Semi-Continuous Reactor

A numerical study describes the catalytic conversion of glucose into ethylene glycol (EG) in a semi-batch reactor. This analysis couples a set of power law models (homogeneous reactions) and Langmuir-Hinshelwood-Hougen-Watson (LHHW) equations (hydrogenations). For this purpose, the kinetic parameters of the LHHW expressions are estimated for the reaction conditions. Then, the kinetic model evaluates the influence of the H₂ pressure and the catalyst concentrations on the selectivity. The results indicate that the EG yield is increased by setting the temperature and the H₂ pressure. In this manner, the process reduces the hexitols and methane production and increases the EG yield. The originality of the work is based on the influence of the H₂ pressure and the catalyst concentrations in the model.     

The use of a basic safety investment model in a practical risk management context

We consider a basic model in economic safety analysis: a firm is willing to invest an amount x in safety measures to avoid an accident A, which in the case of occurrence, leads to a loss of size L. The probability of an accident is a function of x. The optimal value of x is determined by minimizing the expected costs. In the paper, we re-examine this model by adopting a practical risk/safety management perspective. We question how this model can be used for guiding the firm and regulators in determining the proper level of investment in safety. Attention is given to issues like how to determine the probability of an accident and how to take into account uncertainties that extend beyond the expected value. It is concluded that the model, with suitable extensions and if properly implemented, provides a valuable decision support tool. By focusing on investment levels and stimulating thereby the generation of alternative risk-reducing measures, the model is considered particularly useful in risk reduction (ALARP) processes.     

Cadmium Modifies the Cell Cycle and Apoptotic Profiles of Human Breast Cancer Cells Treated with 5-Fluorouracil

Industrialisation, the proximity of factories to cities, and human work activities have led to a disproportionate use of substances containing heavy metals, such as cadmium (Cd), which may have deleterious effects on human health. Carcinogenic effects of Cd and its relationship with breast cancer, among other tumours, have been reported. 5-Fluorouracil (5-FU) is a fluoropyrimidine anticancer drug used to treat solid tumours of the colon, breast, stomach, liver, and pancreas. The purpose of this work was to study the effects of Cd on cell cycle, apoptosis, and gene and protein expression in MCF-7 breast cancer cells treated with 5-FU. Cd altered the cell cycle profile, and its effects were greater when used either alone or in combination with 5-FU compared with 5-FU alone. Cd significantly suppressed apoptosis of MCF-7 cells pre-treated with 5-FU. Regarding gene and protein expression, bcl2 expression was mainly upregulated by all treatments involving Cd. The expression of caspase 8 and caspase 9 was decreased by most of the treatments and at all times evaluated. C-myc expression was increased by all treatments involving Cd, especially 5-FU plus Cd at the half time of treatment. Cd plus 5-FU decreased cyclin D1 and increased cyclin A1 expression. In conclusion, our results indicate that exposure to Cd blocks the anticancer effects of 5-FU in MCF-7 cells. These results could have important clinical implications in patients treated with 5-FU-based therapies and who are exposed to high levels of Cd.     

A Delphi study of knowledge management systems: Scope and requirements

We empirically explored the roles and scope of knowledge management systems in organizations. Building on a knowledge-based view of the firm, we hypothesized and empirically tested our belief that more integration is needed between technologies intended to support knowledge and those supporting business operations. Findings from a Delphi study and in-depth interviews illustrated this and led us to suggest a revised approach to developing organizational knowledge management systems.