954 resultados para Triton X-100


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OBJECTIVE: To test the hypothesis that endovascular revascularization of femoropopliteal lesions improves the impaired venoarteriolar response (VAR) in patients with atherosclerosis. METHODS: We prospectively compared VARs in 15 healthy controls (18 legs) and 14 patients (17 legs) with mild to moderate peripheral arterial disease before and after successful peripheral endovascular angioplasty of femoropopliteal lesions. In all subjects, foot skin blood flow was assessed by laser Doppler flowmetry in the horizontal (HBF) and sitting (SBF) positions. VAR was calculated as (HBF - SBF)/HBF x 100. RESULTS: In patients with peripheral arterial disease, mean HBF (in arbitrary units [AU]; mean +/- SD) was similar before (25.6 +/- 15.3 AU) and after (27.0 +/- 16.4 AU) angioplasty (P = .67), whereas SBF was significantly lower after than before the endovascular procedure (11.6 +/- 7.7 AU to 18.4 +/- 14.1 AU; P < .05). Intragroup differences between SBF and HBF were significant before and after angioplasty (P < .001). VAR was higher after angioplasty (55.1% +/- 21.2%) compared with VAR before intervention (33.4% +/- 20.2%; P = .015). Although VAR increased after the intervention, VAR was still lower than in healthy controls (68.4% +/- 20.5%; P = .025). During the 6 months of follow-up, the ankle-brachial index and VAR remained unchanged (P > .05). CONCLUSIONS: Patients with mild to moderate peripheral arterial disease have an impaired orthostatic autoregulation that improves after successful endovascular revascularization of femoropopliteal obstructive lesions. The effect on VAR is sustained in the absence of restenosis.

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OBJECTIVE: To investigate whether intermittent pneumatic compression (IPC) augments skin blood flow through transient suspension of local vasoregulation, the veno-arteriolar response (VAR), in healthy controls and in patients with peripheral arterial disease (PAD). METHODS: Nineteen healthy limbs and twenty-two limbs with PAD were examined. To assess VAR, skin blood flow (SBF) was measured using laser Doppler fluxmetry in the horizontal and sitting positions and was defined as percentage change with postural alteration [(horizontal SBF--sitting SBF)/horizontal SBF x 100]. On IPC application to the foot, the calf, or both, SBF was measured with laser Doppler fluxmetry, the probe being attached to the pulp of the big toe. RESULTS: Baseline VAR was higher in the controls 63.8 +/- 6.4% than in patients with PAD (31.7 +/- 13.4%, P = .0162). In both groups SBF was significantly higher with IPC than at rest (P < .0001). A higher percentage increase with IPC was demonstrated in the controls (242 +/- 85% to 788 +/- 318%) than in subjects with PAD, for each one of the three different IPC modes investigated (98 +/- 33% to 275 +/- 72%) with IPC was demonstrated. The SBF enhancement with IPC correlated with VAR for all three compression modes (r = 0.58, P = .002 for calf compression, r = 0.65, P < .0001 for foot compression alone, and r = 0.64, P = .0002 for combined foot and calf compression). CONCLUSION: The integrity of the veno-arteriolar response correlates with the level of skin blood flow augmentation generated with intermittent pneumatic compression, indicating that this may be associated with a transient suspension of the autoregulatory vasoconstriction both in healthy controls and in patients with PAD.

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AIM: The aim of this study was to assess the marginal fit of crowns on the Straumann (ITI) Dental Implant System with special consideration of different casting dental materials. MATERIAL AND METHODS: Sixty porcelain-fused-to-metal crowns were fabricated: 18 crowns on standard cone abutments with an impression cylinder, partially prefabricated analogs, no coping and screw-retained (A); 18 crowns on solid abutments without an impression device, no analogs, no coping and cemented (B); and 18 crowns on solid abutments using an impression transfer cap, an analog with a shoulder, no coping and cemented (C). In each group, six crowns were made on epoxy mastercasts (Bluestar), six on synthetic plaster (Moldasynt) and six on super hard stone (Fujirock). Six additional crowns were fabricated with the transversal screw retention system onto the Octa system with impression transfer caps, metal analogs, gold copings and screw-retained (D). Impregum was used as impression material. Crowns of B and C were cemented with KetacCem. Crowns of A and D were fixed with an occlusal screw torqued at 15 N cm. Crowns were embedded, cut and polished. Under a light microscope using a magnification of x 100, the distance between the crown margin (CM) and the shoulder (marginal gap, MG) and the distance between the CM and the end of the shoulder (crown length, CL) was measured. RESULTS: MGs were 15.4+/-13.2 microm (A), 21.2+/-23.1 microm (B), 11+/-12.1 microm (C) and 10.4+/-9.3 microm (D). No statistically significantly differences using either of the casting materials were observed. CLs were -21.3+/-24.8 microm (A), 3+/-28.9 microm (B), 0.5+/-22 microm (C) and 0.1+/-15.8 microm (D). Crowns were shorter on synthetic casting materials compared with stone casts (P<0.005). CONCLUSIONS: CMs fit precisely with both cemented and screw-retained versions as well as when using no, partial or full analogs.

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The apicomplexan parasite, Theileria annulata, is the causative agent of tropical theileriosis, a devastating lymphoproliferative disease of cattle. The schizont stage transforms bovine leukocytes and provides an intriguing model to study host/pathogen interactions. The genome of T. annulata has been sequenced and transcriptomic data are rapidly accumulating. In contrast, little is known about the proteome of the schizont, the pathogenic, transforming life cycle stage of the parasite. Using one-dimensional (1-D) gel LC-MS/MS, a proteomic analysis of purified T. annulata schizonts was carried out. In whole parasite lysates, 645 proteins were identified. Proteins with transmembrane domains (TMDs) were under-represented and no proteins with more than four TMDs could be detected. To tackle this problem, Triton X-114 treatment was applied, which facilitates the extraction of membrane proteins, followed by 1-D gel LC-MS/MS. This resulted in the identification of an additional 153 proteins. Half of those had one or more TMD and 30 proteins with more than four TMDs were identified. This demonstrates that Triton X-114 treatment can provide a valuable additional tool for the identification of new membrane proteins in proteomic studies. With two exceptions, all proteins involved in glycolysis and the citric acid cycle were identified. For at least 29% of identified proteins, the corresponding transcripts were not present in the existing expressed sequence tag databases. The proteomics data were integrated into the publicly accessible database resource at EuPathDB (www.eupathdb.org) so that mass spectrometry-based protein expression evidence for T. annulata can be queried alongside transcriptional and other genomics data available for these parasites.

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A. N. Turing’s 1936 concept of computability, computing machines, and computable binary digital sequences, is subject to Turing’s Cardinality Paradox. The paradox conjoins two opposed but comparably powerful lines of argument, supporting the propositions that the cardinality of dedicated Turing machines outputting all and only the computable binary digital sequences can only be denumerable, and yet must also be nondenumerable. Turing’s objections to a similar kind of diagonalization are answered, and the implications of the paradox for the concept of a Turing machine, computability, computable sequences, and Turing’s effort to prove the unsolvability of the Entscheidungsproblem, are explained in light of the paradox. A solution to Turing’s Cardinality Paradox is proposed, positing a higher geometrical dimensionality of machine symbol-editing information processing and storage media than is available to canonical Turing machine tapes. The suggestion is to add volume to Turing’s discrete two-dimensional machine tape squares, considering them instead as similarly ideally connected massive three-dimensional machine information cells. Three-dimensional computing machine symbol-editing information processing cells, as opposed to Turing’s two-dimensional machine tape squares, can take advantage of a denumerably infinite potential for parallel digital sequence computing, by which to accommodate denumerably infinitely many computable diagonalizations. A three-dimensional model of machine information storage and processing cells is recommended on independent grounds as better representing the biological realities of digital information processing isomorphisms in the three-dimensional neural networks of living computers.

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We obtained major and trace element data on 113 samples from basalts drilled during DSDP Legs 69 and 70 in the Costa Rica Rift area. The majority have major and trace element characteristics typical of ocean-ridge tholeiities. Most of the basalts are relatively MgO rich (MgO > 8 wt.%) and have Mg values (MgO/MgO + 0.85FeO x 100) of about 53, characteristics that clearly indicate that the various magmas underwent only a small amount of crystal fractionation before being erupted onto the seafloor. According to their normative mineralogies, the rocks are olivine tholeiites. A few samples plot close to the diopside-hypersthene join of the projected basalt tetrahedron. Except for basalts from two thin intervals in Hole 504B, which differ significantly from all the other basalts of the hole, practically no chemical downhole variation could be established. In the two exceptional intervals, both TiO2 and P2O5 contents are markedly enriched among the major oxides. The trace elements in these intervals are distinguished by relatively high contents of magmatophile elements and have flat to enriched chondrite-normalized distribution patterns of light rare earth elements (LREE). Most of the rocks outside these intervals are strongly depleted in large-ionlithophile (LIL) elements and LREE. We offer no satisfactory hypothesis for the origin of these basalts at this time. They might have originated within pockets of mantle materials that were more primitive than the LIL-element-depleted magmas that were the source of the other basalts. A significant change with depth in the type of alteration occurs in the 561 meters of basalt cored in Hole 504B. According to the behavior of such alteration-sensitive species as K2O, H2O-, CO2, S, Tl, and the iron oxidation ratio, the alteration is oxidative in the upper part and nonoxidative or even reducing in the lower part. The oxidative alteration may have resulted from low temperature basalt/seawater interaction, whereas hydrothermal solutions may be responsible for the nonoxidative alteration.

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Analysis for micro-molar concentrations of nitrate and nitrite, nitrite, phosphate, silicate and ammonia was undertaken on a SEAL Analytical UK Ltd, AA3 segmented flow autoanalyser following methods described by Kirkwood (1996). Samples were drawn from Niskin bottles on the CTD into 15ml polycarbonate centrifuge tubes and kept refrigerated at approximately 4oC until analysis, which generally commenced within 30 minutes. Overall 23 runs with 597 samples were analysed. This is a total of 502 CTD samples, 69 underway samples and 26 from other sources. An artificial seawater matrix (ASW) of 40g/litre sodium chloride was used as the inter-sample wash and standard matrix. The nutrient free status of this solution was checked by running Ocean Scientific International (OSI) low nutrient seawater (LNS) on every run. A single set of mixed standards were made up by diluting 5mM solutions made from weighed dried salts in 1litre of ASW into plastic 250ml volumetric flasks that had been cleaned by washing in MilliQ water (MQ). Data processing was undertaken using SEAL Analytical UK Ltd proprietary software (AACE 6.07) and was performed within a few hours of the run being finished. The sample time was 60 seconds and the wash time was 30 seconds. The lines were washed daily with wash solutions specific for each chemistry, but comprised of MQ, MQ and SDS, MQ and Triton-X, or MQ and Brij-35. Three times during the cruise the phosphate and silicate channels were washed with a weak sodium hypochlorite solution.

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High resolution palynological and geochemical data of sediment core GeoB 3910-2 (located offshore Northeast Brazil) spanning the period between 19 600 and 14 500 calibrated year bp (19.6-14.5 ka) show a land-cover change in the catchment area of local rivers in two steps related to changes in precipitation associated with Heinrich Event 1 (H1 stadial). At the end of the last glacial maximum, the landscape in semi-arid Northeast Brazil was dominated by a very dry type of caatinga vegetation, mainly composed of grasslands with some herbs and shrubs. After 18 ka, considerably more humid conditions are suggested by changes in the vegetation and by Corg and C/N data indicative of fluvial erosion. The caatinga became wetter and along lakes and rivers, sedges and gallery forest expanded. The most humid period was recorded between 16.5 and 15 ka, when humid gallery (and floodplain) forest and even small patches of mountainous Atlantic rain forest occurred together with dry forest, the latter being considered as a rather lush type of caatinga vegetation. During this humid phase erosion decreased as less lithogenic material and more organic terrestrial material were deposited on the continental slope of northern Brazil. After 15 ka arid conditions returned. During the humid second phase of the H1 stadial, a rich variety of landscapes existed in Northeast Brazil and during the drier periods small pockets of forest could probably survive in favorable spots, which would have increased the resilience of the forest to climate change.

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Multiple copies of Cretaceous black shales extending from the early Cenomanian to the end of the Santonian were recovered at five sites on Demerara Rise during Leg 207 of the Ocean Drilling Program. These sediments are primarily composed of laminated organic-rich claystones interbedded with coarser, lightly laminated foraminferal-bearing packstones and wackestones. The black shales represent the local expression of widespread organic-rich sedimentation in the Atlantic during the mid-Cretaceous. However, incomplete recovery prevented construction of continuous composite sections, resulting in uncertainties concerning the correct stratigraphic placement of individual cores. By combining high-resolution measurements of bulk density collected shipboard on the multisensor track with continuous downhole measurements of formation resistivity using the Formation MicroScanner, an equivalent logging depth scale was constructed for black shales recovered from Sites 1258, 1260, and 1261. The integrated depths approach centimeter-scale resolution and are supported by comparisons of coarser resolution natural gamma ray emissions collected on cores and through downhole logging operations. The new depths highlight the extent of both intra- and intercore gaps and provide an opportunity to further constrain temporal and spatial paleoceanographic changes captured in proxy records from these sediments.

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Bioaccumulation of trace metals in carbonate shells of mussels and clams was investigated at seven hydrothermal vent fields of the Mid-Atlantic Ridge (Menez Gwen, Snake Pit, Rainbow, and Broken Spur) and the Eastern Pacific (9°N and 21°N at the East Pacific Rise and the southern trough of Guaymas Basin, Gulf of California). Mineralogical analysis showed that carbonate skeletons of mytilid mussel Bathymodiolus sp. and vesicomyid clam Calyptogena m. are composed mainly of calcite and aragonite, respectively. The first data were obtained for contents of a variety of chemical elements in bivalve carbonate shells from various hydrothermal vent sites. Analyses of chemical compositions (including Fe, Mn, Zn, Cu, Cd, Pb, Ag, Ni, Cr, Co, As, Se, Sb, and Hg) of 35 shell samples and 14 water samples from mollusk biotopes revealed influences of environmental conditions and some biological parameters on bioaccumulation of metals. Bivalve shells from hydrothermal fields with black smokers are enriched in Fe and Mn by factor of 20-30 relative to the same species from the Menez Gwen low-temperature vent site. It was shown that essential elements (Fe, Mn, Ni, and Cu) more actively accumulated during early ontogeny of the shells. High enrichment factors of most metals (n x 100 - n x 10000) indicate efficient accumulation function of bivalve carbonate shells. Passive metal accumulation owing to adsorption on shell surfaces was estimated to be no higher than 50% of total amount and varied from 14% for Fe to 46% for Mn.

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CaCO3 content was determined on board ship by the "Karbonat Bomb" technique (Müller and Gastner, 1971). In this simple procedure, a sample is powdered and treated with HCl in a closed cylinder. Any resulting CO2 pressure is proportional to the CaCO3 content of the sample. Application of the calibration factor to the manometer reading (x 100) yields per cent CaCO3. The error can be as low as 1 per cent for sediments high in CaCO3, and in general an accuracy of ±2 to 5 per cent can be obtained.

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The ground surface temperature is one of the key parameters that determine the thermal regime of permafrost soils in arctic regions. Due to remoteness of most permafrost areas, monitoring of the land surface temperature (LST) through remote sensing is desirable. However, suitable satellite platforms such as MODIS provide spatial resolutions, that cannot resolve the considerable small-scale heterogeneity of the surface conditions characteristic for many permafrost areas. This study investigates the spatial variability of summer surface temperatures of high-arctic tundra on Svalbard, Norway. A thermal imaging system mounted on a mast facilitates continuous monitoring of approximately 100 x 100 m of tundra with a wide variability of different surface covers and soil moisture conditions over the entire summer season from the snow melt until fall. The net radiation is found to be a control parameter for the differences in surface temperature between wet and dry areas. Under clear-sky conditions in July, the differences in surface temperature between wet and dry areas reach up to 10K. The spatial differences reduce strongly in weekly averages of the surface temperature, which are relevant for the soil temperature evolution of deeper layers. Nevertheless, a considerable variability remains, with maximum differences between wet and dry areas of 3 to 4K. Furthermore, the pattern of snow patches and snow-free areas during snow melt in July causes even greater differences of more than 10K in the weekly averages. Towards the end of the summer season, the differences in surface temperature gradually diminish. Due to the pronounced spatial variability in July, the accumulated degree-day totals of the snow-free period can differ by more than 60% throughout the study area. The terrestrial observations from the thermal imaging system are compared to measurements of the land surface temperature from the MODIS sensor. During periods with frequent clear-sky conditions and thus a high density of satellite data, weekly averages calculated from the thermal imaging system and from MODIS LST agree within less than 2K. Larger deviations occur when prolonged cloudy periods prevent satellite measurements. Futhermore, the employed MODIS L2 LST data set contains a number of strongly biased measurements, which suggest an admixing of cloud top temperatures. We conclude that a reliable gap filling procedure to moderate the impact of prolonged cloudy periods would be of high value for a future LST-based permafrost monitoring scheme. The occurrence of sustained subpixel variability of the summer surface temperature is a complicating factor, whose impact needs to be assessed further in conjunction with other spatially variable parameters such as the snow cover and soil properties.

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Hole 1256C was cored 88.5 m into basement, and Hole 1256D, the deep reentry hole, was cored 502 m into basement during Ocean Drilling Program Leg 206. Hole 1256D is located ~30 m south of Hole 1256C (Wilson, Teagle, Acton, et al., 2003, doi:10.2973/odp.proc.ir.206.2003). A thick massive flow drilled in both holes, Units 1256C-18 and 1256D-1, consists of a single cooling unit of cryptocrystalline to fine-grained basalt, interpreted as a ponded lava, 32 m and at least 74.2 m thick, respectively. This ponded flow gives us a unique opportunity to examine textural variations from the glassy, folded crust of the lava pond recovered from the top of Unit 1256C-18 through the coarse-grained, thick massive lava body to the unusually recrystallized and deformed base cored in Unit 1256C-18. Some detailed descriptions of the textures and grain size variations through the lava pond (Units 1256C-18 and 1256D-1), with special reference to the recrystallization of the base of Unit 1256C-18, are presented here.

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The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conven- tional polyvalent cages (39 cm x 100 cm x 30 cm) and the other half in alternative polyvalent cages (39 cm x 100 cm x 60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight ( P o 0.001), fat and energy content ( P o 0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period ( P o 0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day ( P o 0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P o 0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher ( P o 0.01) and 5.0% lower ( P o 0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days ( P o 0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit.