207 research outputs found

    U.S.-Based Global Intellectual Property Creation: An Analysis

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    Summarizes an analysis of U.S. applications in the international Patent Cooperation Treaty database, with a focus on where innovation is occurring -- in which states, in which companies and universities, and in which technical areas

    Oxidation of Methane by a Biological Dicopper Centre

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    Vast world reserves of methane gas are underutilized as a feedstock for the production of liquid fuels and chemicals owing to the lack of economical and sustainable strategies for the selective oxidation of methane to methanol1. Current processes to activate the strong C–H bond (104 kcal mol−1) in methane require high temperatures, are costly and inefficient, and produce waste2. In nature, methanotrophic bacteria perform this reaction under ambient conditions using metalloenzymes called methane monooxygenases (MMOs). MMOs thus provide the optimal model for an efficient, environmentally sound catalyst3. There are two types of MMO. Soluble MMO (sMMO),expressed by several strains of methanotrophs under copper-limited conditions, oxidizes methane with a well-characterized catalytic di-iron centre4. Particulate MMO (pMMO) is an integral membrane metalloenzyme produced by all methanotrophs and is composed of three subunits, pmoA, pmoB and pmoC, arranged in a trimeric α3β3γ3 complex5. Despite 20 years of research and the availability of two crystal structures, the metal composition and location of the pMMO metal active site are not known. Here we show that pMMO activity is dependent on copper, not iron, and that the copper active site is located in the soluble domains of the pmoB subunit rather than within the membrane. Recombinant soluble fragments of pmoB (spmoB) bind copper and have propylene and methane oxidation activities. Disruption of each copper centre in spmoB by mutagenesis indicates that the active site is a dicopper centre. These findings help resolve the pMMO controversy and provide a promising new approach to developing environmentally friendly C–H oxidation catalysts

    Arthralgia in South Indian patients with pulmonary tuberculosis during treatment with pyrazinamide and rifampicin

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    Arthralgia was the major adverse reaction encountered in a clinical trial of the treatment of pulmonary tuberculosis with three short-course regimens containing pyrazinamide in South Indian patients. The first regimen was of rifampicin, streptomycin, isoniazid and pyrazinamide given daily for three months; the second was of the same four drugs daily for three months followed by streptomycin, isoniazid and pyrazinamide twice-weekly for two months, and the third was the same as the second except that rifampicin was not administered. Arthralgia was reported in 36% of 353 rifampicin patients and 66% of 179 non-rifampicin patients, a highly significant difference (p<0.001). The onset of arthralgia was mostly during the first two months of chemotherapy. The knees were affected in about 90% followed by the ankles in about 50% of the patients with arthralgia, and about 60% of these patients had one or more of the signs, swelling, tenderness and limitation of joint movement. Chemotherapy was modified in 10 rifampicin and 15 non-rifampicin patients; the rest of the patients were managed with symptomatic treatment with analgesics. There was a two to three fold increase in serum uric acid concentrations by the end of the first month and the concentrations were more or less stationary throughout the rest of the daily phase of treatment. The mean concentration during the daily phase of treatment in patients with arthralgia (0.482 mmoles/litre) was similar to that in those without arthralgia (0.484 mmoles/litre), while that in the rifampicin patients (0.476 mmoles/litre) was significantly lower (p=0.03) than that in the non-rifampicin patients (0.495 mmoles/litre)

    Conformational analysis of cyclolinopeptide A, a cyclic nonapeptide: nuclear overhauser effect and energy minimization studies

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    The conformation of cyclolinopeptide A [cyclo(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val)], a naturally occurring cyclic nonapeptide has been investigated in dimethylsulfoxide solution by 270 MHz 1H-nmr. A complete assignment of all C&#945;H and NH resonances has been accomplished using two-dimensional correlated spectroscopy and nuclear Overhauser effects (NOEs). Analysis of interresidue NOEs and JHNC&#945;H values permit construction of a molecular model for the cyclic peptide backbone. The crude model derived from nmr has been used as a starting point for energy minimization, which yields a refined structure largely compatible with nmr observations. The major features of the conformation of cyclolinopeptide A are a Type VI &#946;-turn centered at Pro(1)-Pro(2), with a cis peptide bond between these residues and a &#947;-turn (C7) structure centered at Ile(6). Two intramolecular hydrogen bonds Val(9) CO - Phe(3)NH (4 &#8594;1) and Leu(5) CO - Ile(7)NH (3 &#8594; 1) are observed in the low-energy conformation. The limited solvent accessibility observed for the Val(9) and Leu(5) NH groups in the nmr studies are rationalized in terms of steric shielding

    Intraperitoneal rectal perforation presenting as fetal ascites – a rare occurrence

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    Spontaneous perforation of the rectum presenting as fetal ascites is an extremely rare occurrence. We report the case of an infant where antenatally detected fetal ascites was attributable to intraperitoneal rectal perforation. Investigations directed to identify common causes of this condition did not reveal any aetiology. Patient underwent surgical colostomy formation on day two of life, which was reversed at six weeks of age. We suggest that meconium ascites and peritonitis should be considered as differential diagnoses in fetuses with ascites and, if the neonate requires a laparotomy, the rectal area should be thoroughly inspected to exclude this entity

    The impacts of marketing and operations capabilities on financial performance in the UK retail sector: A resource-based perspective

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    Drawing upon the resource-based view (RBV) of the firm, this study investigates the relationships among marketing capability, operations capability, and financial performance. Using archival data of 186 retail firms in the UK, we find that that marketing capability has a significant impact on operations capability, and that operations capability is significantly and positively related to retail efficiency. The results also suggest that operations capability fully mediates the relationship between marketing capability and financial performance. The findings of this study provide practical insights for practicing managers to consider when developing functional capabilities in order to achieve superior financial performance. © 2013 Elsevier Inc

    Biomass Production Potential of a Wastewater Alga Chlorella vulgaris ARC 1 under Elevated Levels of CO2 and Temperature

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    The growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (ranging from 0.036 to 20%) and temperature (30, 40 and 50°C). The highest chlorophyll concentration (11 μg mL–1) and biomass (210 μg mL–1), which were 60 and 20 times more than that of C. vulgaris at ambient CO2 (0.036%), were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them. Results showed that the optimum temperature for biomass production was 30°C under elevated CO2 (6%). Although increases in temperature above 30°C resulted in concomitant decrease in growth response, their adverse effects were significantly subdued at elevated CO2. There were also differential responses of the alga, assessed in terms of NaH14CO3 uptake and carbonic anhydrase activity, to increases in temperature at elevated CO2. The results indicated that Chlorella vulgaris grew better at elevated CO2 level at 30°C, albeit with lesser efficiencies at higher temperatures

    Long-range effects of histone point mutations on DNA remodeling revealed from computational analyses of SIN-mutant nucleosome structures

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    The packaging of DNA into nucleosomes impedes the binding and access of molecules involved in its processing. The SWI/SNF multi-protein assembly, found in yeast, is one of many regulatory factors that stimulate the remodeling of DNA required for its transcription. Amino-acid point mutations in histones H3 or H4 partially bypass the requirement of the SWI/SNF complex in this system. The mechanisms underlying the observed remodeling, however, are difficult to discern from the crystal structures of nucleosomes bearing these so-called SIN (SWI/SNF INdependent) mutations. Here, we report detailed analyses of the conformations and interactions of the histones and DNA in these assemblies. We find that the loss of direct protein–DNA contacts near point-mutation sites, reported previously, is coupled to unexpected additional long-range effects, i.e. loss of intermolecular contacts and accompanying DNA conformational changes at sequentially and spatially distant sites. The SIN mutations seemingly transmit information relevant to DNA binding across the nucleosome. The energetic cost of deforming the DNA to the states found in the SIN-mutant structures helps to distinguish the mutants that show phenotypes in yeast from those that do not. Models incorporating these deformed dimer steps suggest ways that nucleosomal DNA may be remodeled during its biological processing
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