Dialysis disequilibrium syndrome leading to sudden brain death in a chronic hemodialysis patient

Dialysis disequilibrium syndrome (DDS) is a rare central nervous system (CNS) disease which develops in patients receiving hemodialysis (HD). Although it has been reported in patients receiving chronic HD, DDS is more common during or immediately after the first HD treatment. The exact incidence of DDS is unknown. Death in DDS is an extremely rare phenomenon and to the best of our knowledge only 9 cases have been reported showing this association. We present a unique case of a 42‐year‐old female on chronic HD, and no prior history of CNS disease, who developed brain death in the setting of DDS 2 hours into the dialysis treatment. A literature review of all previously reported cases was performed.     

Simple,green approach for the synthesis of solid support‐embedded PdNPs for ligand exchange

Green approaches have the potential to significantly reduce the costs and environmental impact of chemical syntheses. Here, the authors used green tea (GT) leaf extract to synthesise and anchor palladium nanoparticles (PdNPs) to silica. The synthesised PdNPs in GT extract were characterised by ultraviolet–visible spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. PdNPs primarily formed as capped NPs dispersed in GT extract before reduction completed after 24 h. This capped phytochemical solution was employed as a green precursor solution to synthesise PdNP‐embedded solid supports. The morphology of PdNPs anchored to silica differed to that of PdNPs in solution. Silica‐embedded PdNPs was employed as a new ligand exchanger to isolate trace polycyclic aromatic sulphur heterocycles from a hydrocarbon matrix. The isolation efficiency of the new, greener ligand exchanger was the same as an efficient chemical ligand exchanger and may, therefore, hold promise for future applications.Inspec keywords: nanofabrication, palladium, visible spectra, transmission electron microscopy, nanoparticles, reduction (chemical), ultraviolet spectra, X‐ray diffraction, Fourier transform infrared spectra, surface morphologyOther keywords: ultraviolet–visible spectroscopy, Fourier‐transform infrared spectroscopy, transmission electron microscopy, phytochemical solution, green precursor solution, PdNP‐embedded solid supports, solid support‐embedded PdNPs, green tea leaf extract, chemical ligand exchanger, anchor palladium nanoparticles, X‐ray diffraction, isolate trace polycyclic aromatic sulphur heterocycles, hydrocarbon matrix, green synthesis, time 24.0 hour, Pd     

Separation of no-carrier-added 52Mn from bulk chromium: a simulation study for accelerator mass spectrometry measurement of 53Mn

53Mn radionuclide (T(1/2) = 3.7 x 10(6) y) is produced through the interaction of cosmic rays. Measurements of concentrations of 53Mn in rocks might help to understand Earth surface processes that occurred in time periods not accessible with other cosmogenic nuclides. Only accelerator mass spectrometry (AMS) can determine such ultratrace levels of 53Mn. The main interference in the detection of 53Mn by AMS is its stable isobar 53Cr, which is roughly approximately 10(12) times more abundant in nature. A prerequisite of any AMS measurement of 53Mn in geological samples is therefore chromium separation by an efficient chemistry. Thus, we have developed a method for the separation of chromium and manganese by using a radiometric simulation. The separation procedure was monitored by 51Cr (T(1/2) = 27.70 d) and 52Mn (T(1/2) = 5.59 d) as the corresponding radiotracers for chromium and manganese, respectively. The separation studies were performed by a liquid-liquid extraction technique using trioctylamine (TOA) diluted in cyclohexane. A high separation factor (approximately 16 000) for Mn and Cr can be obtained at optimal conditions of 0.8 M TOA and 9 M HCl. The developed method has been found equally applicable for real geological samples such as manganese crusts, lava, and sediment samples. Therefore, the method offers an important tool to improve 53Mn measurements by AMS.     

Procedures and Practices for Conducting Postevaluation of Information Systems

Postevaluation (PE) of an information system is probably the most neglected activity along the system life cycle. However, PE is essential for making improvements to existing systems and generating standard practices for future information system development projects. Based on actual experience, the 12-step procedure described here can help organizations realize both the future and immediate benefits that PE offers.     

An instrument for measuring the success of the requirements engineering process in information systems development

There exists a strong motivation for evaluating, understanding, and improving requirements engineering practices given that a successful requirements engineering process is necessary for a successful software system. Measuring requirements engineering success is central to evaluation, understanding, and improving these practices. In this paper, a research study whose objective was to develop an instrument to measure the success of the requirements engineering process is described. The domain of this study is developing customer-specific business information systems. The main result is a subjective instrument for measuring requirements engineering success. The instrument consists of 32 indicators that cover the two most important dimensions of requirements engineering success. These two dimensions were identified during the study to be: quality of requirements engineering products and quality of requirements engineering service. Evidence is presented demonstrating that the instrument has desirable psychometric properties, such as high reliability and good validity.This paper is a longer and more detailed version of the study reported in El Emam and Madhavji (1995).This work was supported in part by the IT Macroscope Project and NSERC Canada.     

Distributed database design—Optimization vs feasibility

This paper is concerned with the problem of optimal assignment of data to sites in a distributed relational database. It is shown that in general the optimal allocation will require exponential time in terms of the input. Several heuristic algorithms that can be applied to various constraints and which provide feasible, near optimal results, as well as a model that determines the “best” assignment for a given input out of several optimal and near optimal assignments have been developed. The model is shown to be efficient, to require polynomial time, to be practical in terms of feasible inputs and to achieve assignments with near minimal global and local costs.     

Selection of slab formwork system using fuzzy logic

Formwork plays an important role in building construction. The selection of an appropriate formwork system can reduce project cost, improve quality and speed up the construction process. Although the selection of an appropriate formwork system requires years of experience in formwork design, few experienced personnel may be available, especially in small/medium size contracting companies. With the lack of such experts, the costly outsourcing option becomes essential otherwise the selection of a particular formwork system might not be appropriate. A structured approach is developed to help decision makers in small/medium Egyptian construction companies to select the appropriate horizontal formwork system(s) for their projects. This can be achieved by recognizing the project governing factors affecting the selection process. Based on these factors, a knowledge base is developed to facilitate the process. A fuzzy logic system is used to automate the process and overcome ambiguity and uncertainty in the selection process. The system is shown to be useful and accurate in its application to a real-life case. A survey of formwork experts reveals its ease of use. Further research will expand the system to consider vertical formwork selection to ensure full compatibility.     

Application of 252Cf-PDMS to characterize airborne particles deposited in an Antarctic glacier

The aim of this study is to apply the (252)Cf-PDMS (plasma desorption mass spectrometry) technique to characterize particles deposited in ice samples. This technique allows identification of molecular ions, even large molecules, desorbed from the sample surface, in contrast with PIXE (particle induced X-ray emission) or EDS (energy dispersive spectrometry). Two shallow snow cores obtained from different glacial drainage basins on King George Island ice cap, South Shetland Islands (Antarctica), were analyzed by PDMS. The chemical compounds identified in the ice mass spectra show that the particle contents of both samples were statistically different, indicating a non-homogeneous spatial deposition distribution for the deposited particles. The analysis of the ice mass spectra suggests some possible sources for the airborne particles. The mass spectra of ice samples collected at a site exposed directly to air masses coming from the Drake Passage show a significant contribution of particles from crustal and anthropogenic sources. However, the mass spectra of ice samples taken from a site on a slope towards a local inlet point out a high influence of marine aerosol. Therefore, it was concluded that particles deposited onto the ice cap were attributable to different aerosol sources, besides long-range atmospheric transport. The (252)Cf-PDMS technique can be considered a powerful tool for studies of snow and ice samples, providing important information for understanding the global atmospheric transport and deposition of airborne particles.