999 resultados para 800.1
The lipid bilayer determines helical tilt angle and function in lactose permease of Escherichia coli
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The structure of lactose permease from Escherichia coli in its lipid environment was studied by attenuated total reflection Fourier transform infrared spectroscopy. The protein exhibits an α-helical content of about 65% and about 25% β-sheet. Unusually fast hydrogen/deuterium (H/D) exchange to 90–95% completion suggests a structure that is highly accessible to the aqueous phase. An average tilt angle of 33° for the helices was found with respect to the bilayer normal at a lipid-to-protein ratio of ≈800:1 (mol/mol), and the permease exhibits optimal activity under these conditions. However, upon decreasing the lipid-to-protein ratio, activity decreases continuously in a manner that correlates with the decrease in the lipid order parameter and the increase in the average helical tilt angle. Taken together, the data indicate that the structure and function of the permease are strongly dependent on the order and integrity of the lipid bilayer.
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Mode of access: Internet.
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Mode of access: Internet.
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A Budapesti Corvinus Egyetem Közigazgatástudományi Kara 2006 és 2010 között vett részt abban a kutatásban, amelyet a Versenyképesség Kutató Központ folytatott a közszféra és a gazdaság versenyképessége témájában. A közigazgatás és a versenyképesség kapcsolatának kutatása két fázisban zajlott. A kutatás első fázisa kifejezetten a régiók és gazdasági versenyképesség közötti összefüggésekre fókuszált. A kutatás második szakasza a kutatás tárgyát kiterjesztette és már nem csak a közigazgatási régiókat, hanem a középszintű igazgatást, illetve a középszintű igazgatás átalakításának a közigazgatási szervezet egészére gyakorolt hatását vizsgálta, beleértve annak államszervezeti összefüggéseit is. A kutatás e második szakasza a közigazgatási szervezetrendszert szintén a versenyképesség szempontjából vizsgálta.
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Study Objective: To examine the extent to which justice of decision-making procedures and interpersonal relations is associated with smoking. Setting: Ten municipalities and 21 hospitals in Finland. Design and Participants: Cross-sectional data derived from the Finnish Public Sector Study were analysed with logistic regression analysis models with generalized estimating equations. Analyses of smoking status were based on 34 021 employees. Separate models for heavy smoking (>20 cigarettes per day) were calculated for 6295 current smokers. Main results: After adjustment for age, education, socio-economic position, marital status, job contract, and negative affectivity, smokers who reported low procedural justice were about 1.4 times more likely to smoke >20 cigarettes per day compared with their counterparts with high justice. In a similar way, after adjustments, low justice in interpersonal treatment was significantly associated with an elevated prevalence of heavy smoking (odds ratio (OR) = 1.35, 95% CI = 1.03 to 1.77 for men and OR = 1.41, 95% CI = 1.09 to 1.83 for women). Further adjustment for job strain and effort-reward imbalance had little effect on these results. There were no associations between justice components and smoking status or ex-smoking. Conclusions: The extent to which employees are treated with justice in the workplace seems to be associated with smoking intensity independently of established stressors at work.
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Référence bibliographique : Rol, 60341
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Référence bibliographique : Rol, 61671
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We report on the nonlinear (NL) optical properties of glassy TeO2-GeO2-K2O-Bi2O3 at lambda = 800 nm and lambda = 1,064 nm. Using the Kerr gate technique with a laser delivering 150 fs pulses at 800 nm, we demonstrated the fast NL response of the samples. The modulus of the NL refractive index, n (2), at 800 nm was similar to 10(-15) cm(2)/W. The Z-scan technique was used to determine n (2) a parts per thousand +10(-15) cm(2)/W, at 1,064 nm with pulses of 17 ps. The two-photon absorption coefficient, alpha (2), was smaller than the minimum that we can measure (< 0.003 cm/GW). The figure of merit n (2)/alpha (2) lambda was calculated and indicates that this glass composition has large potential to be used for all-optical switching.
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Rutile (TiO2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 degrees C). In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300-500 degrees C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 GPa and 700-800 degrees C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 degrees C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 degrees C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. The Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 degrees C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 degrees C at >= 2 GPa, but there is no observed dependence on pressure. Together, the data demonstrate that the hydrothermal mobility of Nb is strongly controlled by the composition of the fluid, consistent with published data for Ti. At all experimental conditions, however, the concentration of Nb in the fluid is always lower than coexisting rutile, consistent with a role for rutile in moderating the Nb budget of arc rocks.