Revisiting the Local Scaling Hypothesis in Stably Stratified Atmospheric Boundary Layer Turbulence: an Integration of Field and Laboratory Measurements with Large-eddy Simulations

The `local scaling' hypothesis, first introduced by Nieuwstadt two decades ago, describes the turbulence structure of stable boundary layers in a very succinct way and is an integral part of numerous local closure-based numerical weather prediction models. However, the validity of this hypothesis under very stable conditions is a subject of on-going debate. In this work, we attempt to address this controversial issue by performing extensive analyses of turbulence data from several field campaigns, wind-tunnel experiments and large-eddy simulations. Wide range of stabilities, diverse field conditions and a comprehensive set of turbulence statistics make this study distinct

Phenotypic and pharmacogenetic evaluation of patients with thiazide-induced hyponatremia.

Thiazide diuretics are among the most widely used treatments for hypertension, but thiazide-induced hyponatremia (TIH), a clinically significant adverse effect, is poorly understood. Here, we have studied the phenotypic and genetic characteristics of patients hospitalized with TIH. In a cohort of 109 TIH patients, those with severe TIH displayed an extended phenotype of intravascular volume expansion, increased free water reabsorption, urinary prostaglandin E2 excretion, and reduced excretion of serum chloride, magnesium, zinc, and antidiuretic hormone. GWAS in a separate cohort of 48 TIH patients and 2,922 controls from the 1958 British birth cohort identified an additional 14 regions associated with TIH. We identified a suggestive association with a variant in SLCO2A1, which encodes a prostaglandin transporter in the distal nephron. Resequencing of SLCO2A1 revealed a nonsynonymous variant, rs34550074 (p.A396T), and association with this SNP was replicated in a second cohort of TIH cases. TIH patients with the p.A396T variant demonstrated increased urinary excretion of prostaglandin E2 and metabolites. Moreover, the SLCO2A1 phospho-mimic p.A396E showed loss of transporter function in vitro. These findings indicate that the phenotype of TIH involves a more extensive metabolic derangement than previously recognized. We propose one mechanism underlying TIH development in a subgroup of patients in which SLCO2A1 regulation is altered.This work was supported by an Academy of Medical Sciences grant for clinical lecturers (to JSW and MG), British Heart Foundation grant PG/09/089 (to KMO), the National Institute for Health Research (NIHR) Royal Brompton Cardiovascular Biomedical Research Unit (to JSW and SC), the Fondation Leducq (to JSW and SC), and the British Heart Foundation (to JSW and SC). MDT holds a Medical Research Council Senior Clinical Fellowship (G0902313). This work was supported by the Medical Research Council (grant numbers G510364 and G1000861). This research used the ALICE and SPECTRE High Performance Computing Facilities at the University of Leicester

Fire-Related Carbon Emissions from Land Use Transitions in Southern Amazonia

Various land-use transitions in the tropics contribute to atmospheric carbon emissions, including forest conversion for small-scale farming, cattle ranching, and production of commodities such as soya and palm oil. These transitions involve fire as an effective and inexpensive means for clearing. We applied the DECAF (DEforestation CArbon Fluxes) model to Mato Grosso, Brazil to estimate fire emissions from various land-use transitions during 2001-2005. Fires associated with deforestation contributed 67 Tg C/yr (17 and 50 Tg C/yr from conversion to cropland and pasture, respectively), while conversion of savannas and existing cattle pasture to cropland contributed 17 Tg C/yr and pasture maintenance fires 6 Tg C/yr. Large clearings (>100 ha/yr) contributed 67% of emissions but comprised only 10% of deforestation events. From a policy perspective, results imply that intensification of agricultural production on already-cleared land and policies to discourage large clearings would reduce the major sources of emissions from fires in this region. Copyright 2008 by the American Geophysical Union

Structural studies of T4S systems by electron microscopy

Abstract: Type IV secretion (T4S) systems are large dynamic nanomachines that transport DNA and/or proteins through the membranes of bacteria. Analysis of T4S system architecture is an extremely challenging task taking into account their multi protein organisation and lack of overall global symmetry. Nonetheless the last decade demonstrated an amazing progress achieved by X-ray crystallography and cryo-electron microscopy. In this review we present a structural analysis of this dynamic complex based on recent advances in biochemical, biophysical and structural studies

Optimization of human serum albumin monoliths for chiral separations and high-performance affinity chromatography

Various organic-based monoliths were prepared and optimized for immobilization of the protein human serum albumin (HSA) as a binding agent for chiral separations and high-performance affinity chromatography. These monoliths contained co-polymers based on glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EDMA) or GMA and trimethylolpropane trimethacrylate (TRIM). A mixture of cyclohexanol and 1-dodecanol was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. These monoliths were used with both the Schiff base and epoxy immobilization methods and measured for their final content of HSA. Monoliths showing the highest protein content were further evaluated in chromatographic studies using R/S-warfarin and D/L-tryptophan as model chiral solutes. A 2.6–2.7-fold increase in HSA content was obtained in the final monoliths when compared to similar HSA monoliths prepared according to the literature. The increased protein content made it possible for the new monoliths to provide higher retention and/or two-fold faster separations for the tested solutes when using 4.6 mm i.d. × 50 mm columns. These monoliths were also used to create 4.6 mm i.d. × 10 mm HSA microcolumns that could separate the same chiral solutes in only 1.5–6.0 min. The approaches used in this study could be extended to the separation of other chiral solutes and to the optimization of organic monoliths for use with additional proteins as binding agents

Rare presentation of gallbladder schistosomiasis: a case report

Schistosomiasis is a parasitic disease that is widely considered a neglected tropical disease. It is ranked first after malaria among all parasitic diseases. The major forms of schistosomiasis are intestinal and urogenital; however, gallbladder involvement is rare and usually accompanied by imaging findings similar to those of acute cholecystitis, such as wall thickening or pericholecystic inflammation. We encountered a patient who did not show these typical imaging findings. A man in his late 40s presented to the emergency department with a 2-month history of abdominal distention. His initial laboratory examination showed iron deficiency anemia. Computed tomography revealed a mildly distended gallbladder with septations and a small calcified gallstone. Magnetic resonance imaging was performed for better characterization, and it showed gallbladder stones with multiseptated, cystic gallbladder mural lesions and no wall thickening or pericholecystic fluid. On his second visit, the patient complained of mild epigastric pain. A provisional diagnosis of cholecystitis was considered, and laparoscopic cholecystectomy was performed. Histopathological evaluation revealed a gallbladder wall with multiple foci of chronic granulomatous inflammation. Schistosoma-like ova were observed in the mucosa and submucosa and were consistent with schistosomiasis. Periodic acid–Schiff staining of the ova was positive. The patient’s postoperative course was uneventful