8 research outputs found
CFD and laboratory analysis of axial cross-flow velocity in porous tube packed with differently structured static turbulence promoters
Computational fluid dynamics (CFD) was used for modelling flow regime in a
porous tube. This tube is an ultrafiltration membrane filter made from
zirconium-oxide which is very effective in the separation of stable
oil-in-water microemulsions, especially when the tube is filled with static
mixer. The results of the CFD analysis were used in the preliminary
optimisation of the static mixer’s geometry since it has significant effect
the energy requirement of this advanced membrane technology. The
self-developed static mixers were tested “in vitro” from the aspect of
separation quality and process productivity as well to validate CFD results
and to develop a cost effective, green method to recover unmanageable oily
wastewaters for sustainable development. In this work the results of
computational simulation of the fluid velocity and membrane separation
experiments are discussed
In Situ Electron Microscopy of Lactomicroselenium Particles in Probiotic Bacteria
Electron microscopy was used to test whether or not (a) in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b) the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel) inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM) to digital processing (dTEM), and further to remote-access internet electron microscopy (iTEM). Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200–350 nm) than Lactobacillus casei (L. casei), which generated many, smaller lactomicroSel particles (85–200 nm) and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60–280 nm) in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100–500 nm), but higher relative to those isolated from Streptococcus thermopilus (50–100 nm). These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics
Combination of size exclusion and normal-phase partition modes in high performance liquid chromatography
Influence of instrumental contributions on the apparent column efficiency in high speed gas chromatography
Venous thromboembolism risk and prophylaxis in hospitalised medically ill patients The ENDORSE Global Survey
Limited data are available regarding the risk for venous thromboembolism (VIE) and VIE prophylaxis use in hospitalised medically ill patients. We analysed data from the global ENDORSE survey to evaluate VTE risk and prophylaxis use in this population according to diagnosis, baseline characteristics, and country. Data on patient characteristics, VIE risk, and prophylaxis use were abstracted from hospital charts. VTE risk and prophylaxis use were evaluated according to the 2004 American College of Chest Physicians (ACCP) guidelines. Multivariable analysis was performed to identify factors associated with use of ACCP-recommended prophylaxis. Data were evaluated for 37,356 hospitalised medical patients across 32 countries. VIE risk varied according to medical diagnosis, from 31.2% of patients with gastrointestinal/hepatobiliary diseases to 100% of patients with acute heart failure, active noninfectious respiratory disease, or pulmonary infection (global rate, 41.5%). Among those at risk for VTE, ACCP-recommended prophylaxis was used in 24.4% haemorrhagic stroke patients and 40-45% of cardiopulmonary disease patients (global rate, 39.5%). Large differences in prophylaxis use were observed among countries. Markers of disease severity, including central venous catheters, mechanical ventilation, and admission to intensive care units, were strongly associated with use of ACCP-recommended prophylaxis. In conclusion, VIE risk varies according to medical diagnosis. Less than 40% of at-risk hospitalised medical patients receive ACCP-recommended prophylaxis. Prophylaxis use appears to be associated with disease severity rather than medical diagnosis. These data support the necessity to improve implementation of available guidelines for evaluating VIE risk and providing prophylaxis to hospitalised medical patients