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151.
Goryawala M Guillen MR Cabrerizo M Barreto A Gulec S Barot TC Suthar RR Bhatt RN Mcgoron A Adjouadi M 《IEEE transactions on information technology in biomedicine》2012,16(1):62-69
This study describes a new 3-D liver segmentation method in support of the selective internal radiation treatment as a treatment for liver tumors. This 3-D segmentation is based on coupling a modified k-means segmentation method with a special localized contouring algorithm. In the segmentation process, five separate regions are identified on the computerized tomography image frames. The merit of the proposed method lays in its potential to provide fast and accurate liver segmentation and 3-D rendering as well as in delineating tumor region(s), all with minimal user interaction. Leveraging of multicore platforms is shown to speed up the processing of medical images considerably, making this method more suitable in clinical settings. Experiments were performed to assess the effect of parallelization using up to 442 slices. Empirical results, using a single workstation, show a reduction in processing time from 4.5 h to almost 1 h for a 78% gain. Most important is the accuracy achieved in estimating the volumes of the liver and tumor region(s), yielding an average error of less than 2% in volume estimation over volumes generated on the basis of the current manually guided segmentation processes. Results were assessed using the analysis of variance statistical analysis. 相似文献
152.
This study presents the turbulent flow field in submerged plane wall-jets on horizontal fully rough walls detected by a Vectrino velocimeter. For the comparison between the fully rough and smooth submerged wall-jets, the smooth submerged wall-jet case was also revisited. The two-dimensional Reynolds averaged boundary layer equations of a steady turbulent flow are analyzed to determine the velocity and Reynolds shear stress profiles in the fully developed zone of smooth and fully rough submerged wall-jets. The response of the turbulent flow characteristics in submerged wall-jets to wall roughness is examined from the point of view of similarity characteristics, growth of the length scale, and decay of the velocity and turbulence characteristics scales; and compared with the response of those to smooth and transitionally rough walls. The significant observation is that with an appropriate scaling, the velocity, Reynolds shear stress and turbulence intensities in the fully developed zone of fully rough submerged wall-jets are reasonably similar. The rate of decay of jet-velocity on fully rough walls is greater than that on smooth wall, but it is less than that on transitionally rough walls due to the presence of roughness sub-layer on the fully rough walls. Analysis of the third-order moments of velocity fluctuations reveals that the jet-layer is associated with the arrival of low-speed fluid parcel causing an effect of retardation; while the inner-layer of circulatory flow is associated with the arrival of high-speed fluid parcel causing an effect of acceleration. Wall roughness influences the peak values (both positive and negative) of the third-order moments increasing them significantly. Thus, on fully rough walls, the arrival processes of low- and high-speed fluid parcels become stronger in the jet-layer and the inner-layer of circulatory flow, respectively. Also, the peak values of streamwise and vertical flux of turbulent kinetic energy increase significantly in the presence of fully rough walls. 相似文献
153.
The thermodynamic behaviour of poly(vinylidene fluoride) (PVF2)/poly(methyl acrylate) (PMA) blend gels in diethyl azelate (DEAZ) was studied by differential scanning calorimetry at three different blend compositions (x (weight fraction of PVF2 in the blend) = 0.75, 0.5 and 0.25). Transmission electron microscopy together with optical microscopy indicate the presence of fibrillar network morphology in the gels. The quasi‐binary phase diagrams drawn from both the heating and cooling processes are almost similar, with a hysteresis of 50–60 °C. The possibility of polymer–solvent compound formation in the blend gels have been explored from the composition dependency of enthalpy of gel fusion and enthalpy of gel formation data. Extending the procedure of the pure PVF2/DEAZ gel systems to blend gels, it has been surmised that polymer–solvent compound formation also occurs in blend gels, but the stoichiometry of the complexes varies with blend composition. The shapes of the quasi‐binary phase diagrams of the blend gels are different in some cases from that of pure PVF2/DEAZ, gel indicating that the polymer–solvent compounds are incongruent or singular type depending on the blend compositions. A possible explanation for this behaviour has been offered from entropic and enthalpic viewpoints. Copyright © 2003 Society of Chemical Industry 相似文献
154.
Vesicular and micellar self‐assembly of stimuli‐responsive poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) amphiphilic diblock copolymers
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Kishor Pawar S. N. Raju Kutcherlapati Niranjan Yeole Dilip Hundiwale Tushar Jana 《应用聚合物科学杂志》2018,135(28)
Dually responsive amphiphilic diblock copolymers consisting of hydrophilic poly(N‐isopropyl acrylamide) [poly(NIPAAm)] and hydrophobic poly(9‐anthracene methyl methacrylate) were synthesized by reversible addition fragmentation chain‐transfer (RAFT) polymerization with 3‐(benzyl sulfanyl thiocarbonyl sulfanyl) propionic acid as a chain‐transfer agent. In the first step, the poly(NIPAAm) chain was grown to make a macro‐RAFT agent, and in the second step, the chain was extended by hydrophobic 9‐anthryl methyl methacrylate to yield amphiphilic poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) block copolymers. The formation of copolymers with three different hydrophobic block lengths and a fixed hydrophilic block was confirmed from their molecular weights. The self‐assembly of these copolymers was studied through the determination of the lower critical solution temperature and critical micelle concentration of the copolymers in aqueous solution. The self‐assembled block copolymers displayed vesicular morphology in the case of the small hydrophobic chain, but the morphology gradually turned into a micellar type when the hydrophobic chain length was increased. The variations in the length and chemical composition of the blocks allowed the tuning of the block copolymer responsiveness toward both the pH and temperature. The resulting self‐assembled structures underwent thermally induced and pH‐induced morphological transitions from vesicles to micelles and vice versa in aqueous solution. These dually responsive amphiphilic diblock copolymers have potential applications in the encapsulation of both hydrophobic and hydrophilic drug molecules, as evidenced from the dye encapsulation studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46474. 相似文献
155.
Influence of Linker Length on Conformational Preferences of Glycosylated Sugar Amino Acid Foldamers
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Dr. Yashoda Krishna Sunkari Faiyaz Alam Pancham Singh Kandiyal Dr. Siriwardena Aloysius Dr. Ravi Sankar Ampapathi Dr. Tushar Kanti Chakraborty 《Chembiochem : a European journal of chemical biology》2016,17(19):1839-1844
Glycosylation of foldamers derived from furanoid sugar amino acids with mannose and a propyltriazole linker results in an unprecedented 16/10 mixed‐turn structure in the glycopeptides in water, with a preference for the higher‐order structure irrespective of the stereochemistry of the starting foldamer. This is in stark contrast to the structures displayed by the same oligomers in water when mannosylated with a two‐carbon‐shorter methyltriazole linker: 16‐membered turn structure in the cis‐foldamer and 10‐membered in its trans congener. This demonstrates the defining influence of the linker length on the structural preference of these novel glycopeptide mimics. 相似文献
156.
157.
Characterization of key heavy petroleum feedstock properties is important for optimizing the production of clean transportation fuels. A correlation-based method has been developed to accurately estimate the aromatic carbon and total hydrogen content of heavy petroleum feedstocks. The new characterization methodology is significantly superior to existing methods in that it is applicable to all types of heavy petroleum feedstocks, uses only two (most) commonly measured bulk petroleum properties and is more accurate. The new method has been validated via analysis of an unprecedented number (three hundred and fifty four) of heavy petroleum feedstocks with an extremely broad range of properties. 相似文献
158.
Vachharajani TJ Atray NK 《Hemodialysis international. International Symposium on Home Hemodialysis》2007,11(4):456-460
The population of aging veterans with complex multiple medical problems is increasing steadily in developed nations. The life expectancy in an aging population with end-stage renal disease (ESRD) is often compared with terminal malignancy. Renal failure in elderly patients often generates a myriad of complicated issues and the nephrologists are faced with the dilemma of conveying the prognosis of renal failure in elderly patients and also explain the pros and cons of offering a renal replacement therapy. Our objectives were to assess the cumulative survival in veterans with ESRD over 70 years of age and to evaluate the factors considered for either not initiating or withdrawing from dialysis. All veterans above age 70 years, who were being evaluated for possible dialysis therapy over a 5-year period, were included in the study. The cumulative survival rates at 1 year, 3 years and 5 years were 60%, 37%, and 20%, respectively. Tunneled cuffed catheter was the dialysis access in a third of these patients on dialysis adding to the morbidity. Twenty-four patients considered either not initiating or withdrawing from dialysis therapy after consensus agreement from either the patient or the power of attorney. The decision to initiate dialysis therapy should be made considering the social, ethical, and associated comorbid conditions. A decision to not initiate or withdraw dialysis is possible in critically ill elderly patients and if taken judiciously can reduce physical and mental stress of both the patient and their family members. 相似文献
159.
Sandeep S. Joshi Ashwinkumar S. Dhoble Tushar Sathe Chidanand Mangrulkar 《Applied Solar Energy》2018,54(1):4-9
The paper reports use of silicone oil as spectrum filter and heat absorber for photovoltaic thermal systems. The terrestrial solar spectrum is in the wavelength range of 0.25 to 2.5 μm. The response range of C-Si solar cell is 0.75 to 1.125 μm. In the current study, the feasibility of Silicone oil (Transformer oil) as spectrum filter cum heat absorber for C-Si solar cell is investigated. The spectroscopic analysis of 1 cm thick Silicone oil sample with UV-VIS-NIR spectrophotometer is carried out. This analysis concludes that the Silicone oil is transparent to the response range of C-Si solar cell. Also, it shows a significant absorption for UV and IR part of the spectrum. A glass container with 1 cm thick Silicone oil layer is mounted on the C-Si PV module. The performance of the system is analyzed using solar simulator at irradiance of 1000 W/m2, AM 1.5 G and in natural sunlight at Nagpur (21.10 N, 79.090 E). The experiments were performed for the entire year for time period of one hour in the noon. With Silicone oil spectrum filter, the average electrical efficiency of the PV module was found increase marginally. However, for 10 W module, 27 W average heat gain was recorded. In this study, the surface area of PV module (30 × 35 cm = 0.105 m2) was very small. In actual practice, for large scale installations, significant heat gain is possible. The experimentation and significant outcomes are discussed in this article. 相似文献
160.
The surface properties of sol-gel synthesized anatase titania (TiO2) nanoparticles are probed by sorptiometry, infrared absorption spectroscopy, UV-vis diffuse reflectance spectroscopy and high resolution transmission electron microscopy. The results reveal strong correlations of the surface area, porosity, pyridine adsorption capacity and strength, and catalytic methylbutynol decomposition activity. 相似文献