904 resultados para Double sampling
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Current evidences show that tacrolimus could be a good therapeutic option in patients non-responsive to first-line treatments and even it could become one of the first-line drugs for treating MG. Our study will try to determine the effectivity and safety of tacrolimus in 190 myasthenia gravis patients with suboptimal response to azathioprine: after 12 months of treatment they will be randomized to continue with azathioprine or they will be switched to tacrolimus. Patients will follow the allocated treatment during 14 months and the response will be assessed as well as adverse effectsPURPOSE: To compare azathioprine vs. tacrolimus effectivity and safety in MG patients with suboptimal response to azathioprine at 12 monthsDESIGN: A 14 months multicenter, prospective, randomized, double blind, head to head clinical trial
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Digitoitu 12. 10. 2007.
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The uncertainty of any analytical determination depends on analysis and sampling. Uncertainty arising from sampling is usually not controlled and methods for its evaluation are still little known. Pierre Gy’s sampling theory is currently the most complete theory about samplingwhich also takes the design of the sampling equipment into account. Guides dealing with the practical issues of sampling also exist, published by international organizations such as EURACHEM, IUPAC (International Union of Pure and Applied Chemistry) and ISO (International Organization for Standardization). In this work Gy’s sampling theory was applied to several cases, including the analysis of chromite concentration estimated on SEM (Scanning Electron Microscope) images and estimation of the total uncertainty of a drug dissolution procedure. The results clearly show that Gy’s sampling theory can be utilized in both of the above-mentioned cases and that the uncertainties achieved are reliable. Variographic experiments introduced in Gy’s sampling theory are beneficially applied in analyzing the uncertainty of auto-correlated data sets such as industrial process data and environmental discharges. The periodic behaviour of these kinds of processes can be observed by variographic analysis as well as with fast Fourier transformation and auto-correlation functions. With variographic analysis, the uncertainties are estimated as a function of the sampling interval. This is advantageous when environmental data or process data are analyzed as it can be easily estimated how the sampling interval is affecting the overall uncertainty. If the sampling frequency is too high, unnecessary resources will be used. On the other hand, if a frequency is too low, the uncertainty of the determination may be unacceptably high. Variographic methods can also be utilized to estimate the uncertainty of spectral data produced by modern instruments. Since spectral data are multivariate, methods such as Principal Component Analysis (PCA) are needed when the data are analyzed. Optimization of a sampling plan increases the reliability of the analytical process which might at the end have beneficial effects on the economics of chemical analysis,
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Intensive swine production is an important agricultural and economical activity in Europe. The high availability of pig slurry (PS) lead to attractive fertilization strategy to reduce costs, therefore is mainly applied as fertilizer in agricultural systems. The optimization N fertilization in these areas should be taken in into to avoid nitrates losses by lixiviation and to achieve maximum efficiency in crop nutrition. Many studies have shown that PS applications can achieve satisfactory yields in different crops by partially or completely replacing synthetic fertilizers. In addition, for the last years, in Northeast Spain (Catalonia) has been widely extended the double-cropping forage system.
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The product of catalytic activity of the enzyme phospholipase A2, which resembles the core unit of animal toxins, on phospholipids is a 1:1 mixture of lysolipid and fatty acid. This mixture was studied by time-resolved simultaneous small- and wide angle x-ray diffraction over the temperature range from 23 to 53.5ºC. An unusually large lamellar structure was observed, with d = 11 nm, contradicting the complex functional dimer model between lysolipid and fatty acid. It can be explained by formation of a "double-bilayer", a new phase consisting of two different bilayers, one formed by lysophospholipid and other by fatty acid, bound together by head group interactions. Its strucutre was confirmed by simulations of the X-ray scattering pattern.
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Crystals of Mg/Al layered double hydroxide were synthesized by alkaline precipitation and treated in an aqueous solution of glutamic acid. The glutamate ions were not intercalated into the interlayer space, but were detected in the material by Fourier transform infrared spectroscopy, suggesting that only the external surfaces of crystals were modified with glutamate ions. The resulting hybrid material was tested as a support for immobilization of the enzyme laccase (Myceliophthora thermophila). The immobilized enzyme preparation was characterized by electronic paramagnetic resonance spectroscopy and by assays of catalytic activity. The activity of the immobilized laccase was 97% of the activity in the free enzyme. Layered double hydroxide is a suitable support for use in remediation of soil studies.
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Selective papers of the workshop on "Development of models and forest soil surveys for monitoring of soil carbon", Koli, Finland, April 5-9 2006.
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The tomato cv. Fukuju nº. 2 was used for studying the effect of single and double infections with Potato virus X (PVX) and Tobacco mosaic virus (TMV). Mixed infection resulted in a synergistic increase of disease severity, where more growth reduction was seen with simultaneous inoculations than with sequential inoculations at four-day intervals. At five and 12 days post-inoculation, the increased severity of the disease coincided with enhancement of virus accumulation in the rapidly expanding upper leaves. The PVX concentration in leaves nº 5 to 7 of doubly infected plants was three to six fold that of singly infected ones, as determined by DAS-ELISA. Mixed infection with the L strain led to higher enhancement of PVX than with the TMV-L11A strain. The concentration of TMV-L was lower in double infection and significantly higher than TMV-L11A in both singly and doubly infected plants. Analyses of the PVX ORF2 by Western blot and Northern hybridization revealed the pattern of accumulation of the 25 kDa protein and the RNAs, respectively, following those of the virion and coat protein. The strain TMV-L11A overcame the resistance gene in cv. GCR 237 (Tm-1). In the upper leaf nº. 8, the concentration of PVX was three times higher in plants with mixed infection than with L11A. The concentrations of the L and OM (TMV strains) in both singly and doubly infected plants were at very low levels, and the synergistic effect on PVX concentration and disease severity was not observed.
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This study was carried to evaluate the efficiency of the Bitterlich method in growth and yield modeling of the even-aged Eucalyptus stands. 25 plots were setup in Eucalyptus grandis cropped under a high bole system in the Central Western Region of Minas Gerais, Brazil. The sampling points were setup in the center of each plot. The data of four annual mesurements were colleted and used to adjust the three model types using the age, the site index and the basal area as independent variables. The growths models were fitted for volume and mass of trees. The efficiency of the Bitterlich method was confirmed for generating the data for growth and yield modeling.
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In order to verify Point-Centered Quarter Method (PCQM) accuracy and efficiency, using different numbers of individuals by per sampled area, in 28 quarter points in an Araucaria forest, southern Paraná, Brazil. Three variations of the PCQM were used for comparison associated to the number of sampled individual trees: standard PCQM (SD-PCQM), with four sampled individuals by point (one in each quarter), second measured (VAR1-PCQM), with eight sampled individuals by point (two in each quarter), and third measuring (VAR2-PCQM), with 16 sampled individuals by points (four in each quarter). Thirty-one species of trees were recorded by the SD-PCQM method, 48 by VAR1-PCQM and 60 by VAR2-PCQM. The level of exhaustiveness of the vegetation census and diversity index showed an increasing number of individuals considered by quadrant, indicating that VAR2-PCQM was the most accurate and efficient method when compared with VAR1-PCQM and SD-PCQM.
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Taking into account that the sampling intensity of soil attributes is a determining factor for applying of concepts of precision agriculture, this study aims to determine the spatial distribution pattern of soil attributes and corn yield at four soil sampling intensities and verify how sampling intensity affects cause-effect relationship between soil attributes and corn yield. A 100-referenced point sample grid was imposed on the experimental site. Thus, each sampling cell encompassed an area of 45 m² and was composed of five 10-m long crop rows, where referenced points were considered the center of the cell. Samples were taken from at 0 to 0.1 m and 0.1 to 0.2 m depths. Soil chemical attributes and clay content were evaluated. Sampling intensities were established by initial 100-point sampling, resulting data sets of 100; 75; 50 and 25 points. The data were submitted to descriptive statistical and geostatistics analyses. The best sampling intensity to know the spatial distribution pattern was dependent on the soil attribute being studied. The attributes P and K+ content showed higher spatial variability; while the clay content, Ca2+, Mg2+ and base saturation values (V) showed lesser spatial variability. The spatial distribution pattern of clay content and V at the 100-point sampling were the ones which best explained the spatial distribution pattern of corn yield.
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OBJECTIVE: To elucidate the role of the spleen and splenic allograft in lipid control and evaluate its effect on the lipid profile of rats.METHOD: 32 male Wistar rats were randomly assigned into four groups: control group (1), total splenectomy group (2), splenectomy and implantation of allograft group (3) and double spleen group (4). Each group was subdivided into two subgroups: A and B, based on the death of the animals after 30 or 120 days of monitoring. The procedures in groups 2, 3 and 4 were made simultaneously, and splenectomized animals, groups 2 and 3 were donors, respectively, for the animals of groups 3 and 4. In group 4 the spleen was preserved and the animals received implants from the spleens of rats from group 3. The regeneration of splenic tissue was evaluated by macroscopic and microscopic analyzes of the grafts and own spleens, as well as with measurements of VLDL, HDL, LDL, total cholesterol and triglycerides.RESULTS: after 120 days, Group 4 showed levels of total cholesterol and LDL lower than the other groups. Group 1 had higher levels of lipids.CONCLUSION: The technique of double spleen was effective in the control of lipid metabolism, corroborating the function of the spleen as a reserve of lipids.