Mass transfer in annular, two-phase flow Final report

Mass transfer rate and surface characteristics of air-water interface during annular two-phase flow in vertical pip

Incidence and management of Mirizzi syndrome during laparoscopic cholecystectomy

Background: Benign extrinsic obstruction of the hepatic duct, known as "Mirizzi syndrome” (MS), is an uncommon complication of longstanding cholelithiasis. Since laparoscopic cholecystectomy (LC) replaced the open approach, Mirizzi syndrome has regained the interest of biliary surgeons. Methods: The Swiss Association for Laparoscopic and Thoracoscopic Surgery (SALTS) prospectively collected the data on 13,023 patients undergoing LC between 1995 and 1999. This database was investigated with special regard to patients with Mirizzi syndrome. Results: There were 39 patients (14 men and 25 women; mean age, 61 years) with MS (incidence, 0.3%). Thirty-four patients had type 1 MS and five had type 2. A gallbladder carcinoma was found in four patients (incidence, 11%). In the type 1 group, 23 patients underwent cholecystectomy only, 10 patients had a bile duct exploration and T-tube insertion, and one patient had a Roux-en-Y reconstruction. In three patients with type 2, a hepaticojejunostomy was performed; two others underwent simple closure and drainage (via T-tube) of the biliary fistula. The conversion rate was 74% (24 of 34 patients) in the type 1 group and 100% (five of five patients) for type 2. The overall complication rate was 18%. There were no deaths. Conclusions: Although MS is rarely encountered during LC, it must be recognized intraoperatively. Conversion to an open approach is often needed, and prior to any surgical intervention, gallbladder cancer must be exclude

Chemical crosslinking and mass spectrometry to elucidate the topology of integral membrane proteins.

Here we made an attempt to obtain partial structural information on the topology of multispan integral membrane proteins of yeast by isolating organellar membranes, removing peripheral membrane proteins at pH 11.5 and introducing chemical crosslinks between vicinal amino acids either using homo- or hetero-bifunctional crosslinkers. Proteins were digested with specific proteases and the products analysed by mass spectrometry. Dedicated software tools were used together with filtering steps optimized to remove false positive crosslinks. In proteins of known structure, crosslinks were found only between loops residing on the same side of the membrane. As may be expected, crosslinks were mainly found in very abundant proteins. Our approach seems to hold to promise to yield low resolution topological information for naturally very abundant or strongly overexpressed proteins with relatively little effort. Here, we report novel XL-MS-based topology data for 17 integral membrane proteins (Akr1p, Fks1p, Gas1p, Ggc1p, Gpt2p, Ifa38p, Ist2p, Lag1p, Pet9p, Pma1p, Por1p, Sct1p, Sec61p, Slc1p, Spf1p, Vph1p, Ybt1p)

Saccharomyces cerevisiae, a model to study sterol uptake and transport in eukaryotes, Biochem

Abstract The molecular mechanisms that govern intracellular transport of sterols in eukaryotic cells are only poorly understood. Saccharomyces cerevisiae is a facultative anaerobic organism that requires supplementation with unsaturated fatty acids and sterols to grow in the absence of oxygen, as the synthesis of these lipids requires molecular oxygen. The fact that yeast grows well under anaerobic conditions indicates that lipid uptake is rapid and efficient. To identify components in this lipid uptake and transport pathway, we screened the yeast mutant collection for genes that are essential under anaerobic conditions. Out of the approx. 4800 non-essential genes represented in the mutant collection, 37 were required for growth under anaerobic conditions. Uptake assays using radiolabelled cholesterol revealed that 16 of these genes are required for cholesterol uptake/transport and esterification. Further characterization of the precise role of these genes is likely to advance our understanding of this elusive pathway in yeast and may prove to be relevant to understand sterol homoeostasis in higher eukaryotic cells

EFBAT: exact family-based association tests

Background: Family-based association tests are important tools for investigating genetic risk factors of complex diseases. These tests are especially valuable for being robust to population structure. We introduce a tool, EFBAT, which performs exact family-based tests of association for X-chromosome and autosomal biallelic markers. Results: The program EFBAT extends a network algorithm previously applied to autosomal markers to include the X-chromosome and to perform tests of association under the null hypotheses "no association, no linkage" and "no association in the presence of linkage" under additive, dominant and recessive genetic models. These tests are valid regardless of patterns of missing familial data. Conclusion: The general framework for performing exact family-based association tests has been usefully extended to the X-chromosome, particularly for the hypothesis of "no association in the presence of linkage" and for different genetic models

3D numerical model of the Omega Nebula (M17): simulated thermal X-ray emission

We present 3D hydrodynamical simulations of the superbubble M17, also known as the Omega nebula, carried out with the adaptive grid code yguazu'-a, which includes radiative cooling. The superbubble is modelled considering the winds of 11 individual stars from the open cluster inside the nebula (NGC 6618), for which there are estimates of the mass loss rates and terminal velocities based on their spectral types. These stars are located inside a dense interstellar medium, and they are bounded by two dense molecular clouds. We carried out three numerical models of this scenario, considering different line of sight positions of the stars (the position in the plane of the sky is known, thus fixed). Synthetic thermal X-ray emission maps are calculated from the numerical models and compared with ROSAT observations of this astrophysical object. Our models reproduce successfully both the observed X-ray morphology and the total X-ray luminosity, without taking into account thermal conduction effects.Comment: 8 pages, 6 figures, accepted for publication in MNRA