29 resultados para 3D and 2D background modelling


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Non-syndromic cleft lip with or without cleft palate (NS CL/P) is a complex disease in which heritability estimates vary widely depending on the population studied. To evaluate the importance of genetic contribution to NS CL/P in the Brazilian population, we conducted a study with 1,042 families from five different locations (Santarem, Fortaleza, Barbalha, Maceio, and Rio de Janeiro). We also evaluated the role of consanguinity and ethnic background. The proportion of familial cases varied significantly across locations, with the highest values found in Santarem (44%) and the lowest in Maceio (23%). Heritability estimates showed a higher genetic contribution to NS CL/P in Barbalha (85%), followed by Santarem (71%), Rio de Janeiro (70%), Fortaleza (64%), and Maceio (45%). Ancestry was not correlated with the occurrence of NS CL/P or with the variability in heritability. Only in Rio de Janeiro was the coefficient of inbreeding significantly larger in NS CL/P families than in the local population. Recurrence risk for the total sample was approximately 1.5-1.6%, varying according to the location studied (0.6-0.7% in Maceio to 2.2-2.8% in Barbalha). Our findings show that the degree of genetic contribution to NS CL/P varies according to the geographic region studied, and this difference cannot be attributed to consanguinity or ancestry. These findings suggest that Barbalha is a promising region for genetic studies. The data presented here will be useful in interpreting results from molecular analyses and show that care must be taken when pooling samples from different populations for association studies. (C) 2011 Wiley-Liss, Inc.

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Radiation dose calculations in nuclear medicine depend on quantification of activity via planar and/or tomographic imaging methods. However, both methods have inherent limitations, and the accuracy of activity estimates varies with object size, background levels, and other variables. The goal of this study was to evaluate the limitations of quantitative imaging with planar and single photon emission computed tomography (SPECT) approaches, with a focus on activity quantification for use in calculating absorbed dose estimates for normal organs and tumors. To do this we studied a series of phantoms of varying complexity of geometry, with three radionuclides whose decay schemes varied from simple to complex. Four aqueous concentrations of (99m)Tc, (131)I, and (111)In (74, 185, 370, and 740 kBq mL(-1)) were placed in spheres of four different sizes in a water-filled phantom, with three different levels of activity in the surrounding water. Planar and SPECT images of the phantoms were obtained on a modern SPECT/computed tomography (CT) system. These radionuclides and concentration/background studies were repeated using a cardiac phantom and a modified torso phantom with liver and ""tumor"" regions containing the radionuclide concentrations and with the same varying background levels. Planar quantification was performed using the geometric mean approach, with attenuation correction (AC), and with and without scatter corrections (SC and NSC). SPECT images were reconstructed using attenuation maps (AM) for AC; scatter windows were used to perform SC during image reconstruction. For spherical sources with corrected data, good accuracy was observed (generally within +/- 10% of known values) for the largest sphere (11.5 mL) and for both planar and SPECT methods with (99m)Tc and (131)I, but were poorest and deviated from known values for smaller objects, most notably for (111)In. SPECT quantification was affected by the partial volume effect in smaller objects and generally showed larger errors than the planar results in these cases for all radionuclides. For the cardiac phantom, results were the most accurate of all of the experiments for all radionuclides. Background subtraction was an important factor influencing these results. The contribution of scattered photons was important in quantification with (131)I; if scatter was not accounted for, activity tended to be overestimated using planar quantification methods. For the torso phantom experiments, results show a clear underestimation of activity when compared to previous experiment with spherical sources for all radionuclides. Despite some variations that were observed as the level of background increased, the SPECT results were more consistent across different activity concentrations. Planar or SPECT quantification on state-of-the-art gamma cameras with appropriate quantitative processing can provide accuracies of better than 10% for large objects and modest target-to-background concentrations; however when smaller objects are used, in the presence of higher background, and for nuclides with more complex decay schemes, SPECT quantification methods generally produce better results. Health Phys. 99(5):688-701; 2010

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A phytochemical investigation of the leaves and stems of Peperomia obtusifolia (Piperaceae) yielded a new flavone C-diglycoside isoswertisin-4`-methyl-ether-2 ``alpha-L-rhamnoside (1), along with four known compounds: isoswertisin-2 ``alpha-L-rhamnoside (2), (+)-diayangambin (3), 2-episesalatin (4) and corchoionoside C (5). The structures of the two flavone C-diglycosides (1, 2) were elucidated on the basis of 1D and 2D NMR spectroscopy and MS spectrometric data. These flavones were evaluated by bioautographic assay against Cladosporium cladosporioides and C. sphaerospermum and showed weak antifungal activity.

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Resol type resins were prepared in alkaline conditions (potassium hydroxide or potassium carbonate) using furfural obtained by acid hydrolysis of abundant renewable resources from agricultural and forestry waste residues. The structures of the resins were fully determined by H-1, C-13, and 2D NMR spectrometries with the help of four models compounds synthesized specially for this study. MALDI-Tof mass spectrometry experiments indicated that a majority of linear oligomers and a minority of cyclic ones constituted them. Composites were prepared with furfural-phenol resins and sisal fibers. These fibers were chosen mainly because they came from natural lignocellulosic material and they presented excellent mechanical microscopy images indicated that the composites displayed excellent adhesion between resin and fibers. Impact strength measurement showed that mild conditions were more suitable to prepare thermosets. Nevertheless, mild conditions induced a high-diffusion coefficient for water absorption by composites. Composites with good properties could be prepared using high proportion of materials obtained from biomass without formaldehyde. (c) 2008 Wiley Periodicals, Inc.

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A phytochemical investigation of the ethanolic extract of stalks of Senna martiana Benth. (Leguminoseae), native specie of northeast Brazil, resulted in the isolation and spectroscopic characterization of a new bianthrone glycoside, martianine 1 (10,10'-il-chrysophanol-10-oxi10,10'-bi-glucosyl). Its identification was established by HRMS, IR and 2D NMR experiments. The evaluation of martianine trypanocidal activity was carried out against gliceraldehyde 3-phosphate dehydrogenase enzyme from Trypanosoma cruzi. Its inhibitory constant (Ki) is in the low micromolar concentration and it was determined by isothermal titration calorimetry to be 27.3 ± 2.47 µmol L-1. The non-competitive mechanism is asserted to be putative of the mode of action martianine displays against T. cruzi GAPDH. Results show that martianine has a great potential to become new lead molecule by inhibiting this key enzyme and for the development of new drugs against Chagas disease.

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Objective: To evaluate the influence of 810-nm-diode laser irradiation, applied before root canal filling, on apical sealing ability of three different resin-based sealers (AH Plus, EndoRez, and RealSeal). Background: Lasers have been widely used in endodontics. The dentin wall changes caused by laser irradiation could improve the sealing ability of endodontic cements. Methods: Sixty single-rooted human teeth were divided into six groups, according to the endodontic sealer used and previous 810-nm-diode laser irradiation. The protocol for laser irradiation was 2.5W in a continuous wave, in scanning mode, with four irradiations per tooth. After sample preparation, they were analyzed according to apical leakage with silver nitrate impregnation. Results: The RealSeal sealer achieved minimum leakage rates (1.24 mm), with significant differences at the 1% level (Tukey's test, p < 0.01) from AH Plus (1.84 mm) in nonirradiated groups. When the laser was used, there were also significant differences at the 5% level (p < 0.05) between irradiated groups (1.31 and 1.78 mm, respectively). Conclusion: The 810-nm-diode laser irradiation did not promote significant differences in apical leakage.

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Creation of cold dark matter (CCDM) can macroscopically be described by a negative pressure, and, therefore, the mechanism is capable to accelerate the Universe, without the need of an additional dark energy component. In this framework, we discuss the evolution of perturbations by considering a Neo-Newtonian approach where, unlike in the standard Newtonian cosmology, the fluid pressure is taken into account even in the homogeneous and isotropic background equations (Lima, Zanchin, and Brandenberger, MNRAS 291, L1, 1997). The evolution of the density contrast is calculated in the linear approximation and compared to the one predicted by the Lambda CDM model. The difference between the CCDM and Lambda CDM predictions at the perturbative level is quantified by using three different statistical methods, namely: a simple chi(2)-analysis in the relevant space parameter, a Bayesian statistical inference, and, finally, a Kolmogorov-Smirnov test. We find that under certain circumstances, the CCDM scenario analyzed here predicts an overall dynamics (including Hubble flow and matter fluctuation field) which fully recovers that of the traditional cosmic concordance model. Our basic conclusion is that such a reduction of the dark sector provides a viable alternative description to the accelerating Lambda CDM cosmology.

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A new phenylpropanoid and two new diterpenes were isolated from the leaves of the plant Mikania laevigata Shultz Bip. ex Baker. The structures of these compounds were established by 1D- and 2D-nuclear magnetic resonance spectroscopic techniques and mass spectrometry data. Taraxerol, lupeol, coumarin, syringaldehyde, trans-melilotoside, cis-melilotoside, adenosine, patuletin 3-O-beta-D-glucopyranoside, kaempferol 3-O-beta-D-glucopyranoside, quercetin 3-O-beta-D-glucopyranoside, methyl 3,5-di-O-caffeoyl quinate, and 3,3`,5-trihydroxy-4`,6,7-trimethoxyflavone were isolated too. In addition, the compounds dihydrocoumarin, spathulenol, caryophyllene oxide, kaurenoic acid, beyerenoic acid, and lupeol acetate were identified by GC-MS. (C) 2010 Elsevier Ltd. All rights reserved.

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A novel labdane diterpene was isolated from the plant Acritopappus longifolius. The structure of this compound was established by 1D- and 2D-nuclear magnetic resonance spectroscopic techniques and mass spectrometry data. N-Methyl-4-hydroxy-trans-proline, stigmasterol-3-O-beta-D-glycoside. and the flavonoids quercetin, luteolin, kaempferol, and rutin were also isolated. (C) 2010 Elsevier Ltd. All rights reserved.

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A lignan with a new skeleton named chimarrhinin (1) was isolated from an extract of the leaves of Chimarrhis turbinata, a Rubiaceae plant species. (13)C NMR spectrometric techniques including 1D and 2D experiments and HRESIMS provided unequivocal structural confirmation of this new C(6).C(3) skeleton type. The relative configuration of 1 was established by 2D (1)H-H analysis and J couplings, while its conformation was evaluated through molecular modeling using the RM1 semiempirical method, with the aid of coupling constants obtained by NMR analysis. The antioxidant activity of the new derivative 1 and two known and previously isolated phenolic derivatives (2 and 3) was investigated. An IC(50) value of 7.50 +/- 0.5 mu mol L(-1) was obtained for the new derivative 1, while 2 and 3 showed IC(50) values of 18.60 +/- 0.4 and 18.50 +/- 0.6 mu mol, respectively.

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The present study compared two heating methods currently used for antigen retrieval (AR) immunostaining: the microwave oven and the steam cooker. Myosin-V, a molecular motor involved in vesicle transport, was used as a neuronal marker in honeybee Apis mellifera brains fixed in formalin. Overall, the steam cooker showed the most satisfactory AR results. At 100 degrees C, tissue morphology was maintained and revealed epitope recovery, while evaporation of the AR solution was markedly reduced; this is important for stabilizing the sodium citrate molarity of the AR buffer and reducing background effects. Standardization of heat-mediated AR of formalin-fixed and paraffin-embedded tissue sections results in more reliable immunostaining of the honeybee brain.

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Background, aim and scope Although many recent studies have focused on sediment potential toxicity, few of them were performed in tropical shallow aquatic environments. Those places can suffer short-time variations, especially due to water column circulations generated by changes in temperature and wind. Rio Grande reservoir is such an example; aside from that, it suffers various anthropogenic impacts, despite its multiple uses. Materials and methods This work presents the first screening step for understanding sediment quality from Rio Grande reservoir by comparing metal content using three different sediment quality guidelines. We also aimed at verifying any possible spatial heterogeneity. Results and discussion We found spatial heterogeneity varying according to the specific metal. Results showed a tendency for metals to remain as insoluble as metal sulfide (potentially not bioavailable), since sulfide was in excess and sediment physical-chemical characteristics contribute to sulfide maintenance (low redox potential, neutral pH, low dissolved oxygen, and high organic matter content). On the other hand, metal concentrations were much higher than suggested by Canadian guidelines and regional background values, especially Cu, which raises the risk of metal remobilization in cases of water circulation. Further study steps include the temporal evaluation of AVS/SEM, a battery of bioassays and the characterization of organic compounds.

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The methanol extract from aerial parts of the Peperomia blanda (Piperaceae) yielded two C-glycosyl-flavones. Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR, chemical transformation and comparison with the related known compounds. The structure of the new flavonoids were established as 4`-methoxy-vitexin 7-O-beta-D-xylopyranoside (1) (7-O-beta-D-xylopyranosyl-8-C-beta-D-glucopyranosyl-4`-methoxy-apigenin) and vicenin-2 (2). The antioxidant activity of both compounds was investigated using the DPPH assay. Both compounds showed only modest activity, with IC50 values of 357.2 mu M for 1, and 90.5 mu M for 2. (C) 2008 Elsevier B.V. All rights reserved.

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The ethanol extract from Xyris pteygoblephara aerial parts was evaluated against five microorganism strains, by the microdilution and agar diffusion methods. Extract fractionation led to the isolation of three compounds, whose structures were assigned by spectrometric data (113 and 2D NMR, IR, MS and UV) as (3R,4R)-(-)-6-methoxy-3,4-dihydro-3-n-pentil-4-acethoxy-1H-2-benzopyran-1-one (1), moronic acid and quercetin. The absolute configuration of I was defined by circular dichroism spectroscopy and comparison with data reported for other dihydroisocoumarins. Assay of 1 (100 mu g/disc) by the agar diffusion method against clinical isolates of the dermatophytes Epidermophyton floccosum (inhibition zone, mm +/- s.d.: 4.5 +/- 0.8), Trichophyton mentagrophytes (4.8 +/- 0.4) and Trichophyton rubrum (10.2 +/- 0.8) revealed similar inhibition zones to the positive control amphotericin B (32 mu g/disc; 5.0 +/- 0.2; 5.0 +/- 0.6 and 8.8 +/- 1.2, respectively). The result corroborates the ethnomedical use of Xyris species to treat dermatitis. (C) 2007 Elsevier Ltd. All rights reserved.