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排序方式: 共有261条查询结果,搜索用时 31 毫秒
31.
FJ Sampaio 《Canadian Metallurgical Quarterly》1996,102(5-6):199-203
On the basis of their importance for nephron-sparing surgery in tumors of the superior pole of the kidney, we analyzed 3-dimensional endocasts of the intrarenal structures. In 86.6% the superior pole was related to 3 arteries involved in its resection. Management of the superior (apical) segmental artery is in general simple as well as the ligature of the artery related to the anterior surface of the upper infundibulum. Ligature of the branch of the posterior segmental artery, that is related to the upper infundibulum, is critical due to the risk of injuring this segmental artery with loss of a great portion of renal parenchyma. The posterior segmental artery (retropelvic artery) is involved and must be preserved in all cases of superior pole resection. A retropelvic vein with its upper dorsal plexus was present in 69% of the cases. This vein must be previously ligated to provided safe management of the arteries during superior pole resection. 相似文献
32.
33.
L Di Ciero ML Oliva R Torquato P K?hler JK Weder J Camillo Novello CA Sampaio B Oliveira S Marangoni 《Canadian Metallurgical Quarterly》1998,17(8):827-834
Trypsin inhibitors of two varieties of Bauhinia variegata seeds have been isolated and characterized. Bauhinia variegata candida trypsin inhibitor (BvcTI) and B. variegata lilac trypsin inhibitor (BvlTI) are proteins with Mr of about 20,000 without free sulfhydryl groups. Amino acid analysis shows a high content of aspartic acid, glutamic acid, serine, and glycine, and a low content of histidine, tyrosine, methionine, and lysine in both inhibitors. Isoelectric focusing for both varieties detected three isoforms (pI 4.85, 5.00, and 5.15), which were resolved by HPLC procedure. The trypsin inhibitors show Ki values of 6.9 and 1.2 nM for BvcTI and BvlTI, respectively. The N-terminal sequences of the three trypsin inhibitor isoforms from both varieties of Bauhinia variegata and the complete amino acid sequence of B. variegata var. candida L. trypsin inhibitor isoform 3 (BvcTI-3) are presented. The sequences have been determined by automated Edman degradation of the reduced and carboxymethylated proteins of the peptides resulting from Staphylococcus aureus protease and trypsin digestion. BvcTI-3 is composed of 167 residues and has a calculated molecular mass of 18,529. Homology studies with other trypsin inhibitors show that BvcTI-3 belongs to the Kunitz family. The putative active site encompasses Arg (63)-Ile (64). 相似文献
34.
The effect of the addition of a galactomannan (locust bean gum, LBG, or tara gum, TG) on the microstructure and rheological properties of a globular protein (β-lactoglobulin, β-Lg) solution was studied at pH 7.0, when the protein bears a net negative charge. Confocal laser scanning microscopy was used to explore the microstructure. Steady shear and dynamic oscillatory measurements were performed with a controlled stress rheometer AR2000 (TA Instruments) fitted with a cone-and-plate geometry. Mixtures were prepared with 6.5 wt% β-lactoglobulin concentration and 0.31–0.82 wt% LBG or 0.23–0.71 wt% TG concentration. All mixed systems were two-phase. The microstructure was clearly dependent on the concentration of the galactomannan in the mixture: the systems evolved from a continuous matrix of β-lactoglobulin enriched phase containing some small inclusions of the galactomannan, to a matrix of galactomannan-enriched continuous phase containing aggregates of β-lactoglobulin. Modifications of the flow and viscoelastic properties with respect to the individual components were clearly evidenced for the mixed systems. Phase inversion detected by microscopy could also be detected by rheology as a modification in the flow/viscoelastic behaviour. 相似文献
35.
The main kaolin deposits in north Brazil present are contaminated with colored titanous impurities. Conventional beneficiation processes do not completely remove TiO2. The difficulty in separation is mainly due to the ultra-fine size of the minerals.This work presents a study of an alternative kaolin purification method based on selective adsorption of soluble polymers. In the process, flocs were generated by interaction of anionic polyacrylamide with titanous impurities and were separated from the kaolin suspension through sedimentation. 相似文献
36.
Sampaio PN Fortes AM Cabral JM Pais MS Fonseca LP 《Journal of Bioscience and Bioengineering》2008,105(4):305-312
The Saccharomyces cerevisiae W303-1A strain transformed with a centromeric plasmid containing CYPRO11, which codifies the aspartic protease cyprosin B, was grown in a 3 l bioreactor under aerobic conditions. Expression of cyprosin B is directly dependent on the concentration of galactose used as the inducer and carbon source in 1% yeast extract, 2% bactopeptone, and 4% galactose in culture medium. For 4% of galactose, 209 mg.l(-1) total protein, and 1036 U.ml(-1) recombinant cyprosin B activity were obtained from 6.1 g dcw.l(-1) biomass. The recombinant cyprosin B, purified by two consecutive anion-exchange chromatographies (diethyl amino-ethyl [DEAE]-Sepharose and Q-Sepharose XK-16 columns), shows a specific activity of 62 x 10(3) U.mg(-1), corresponding to a purification degree of 12.5-fold and a recovery yield of 25.6% relative to that in fermentation broth. The proteolytic activity of recombinant cyprosin B is optimal at 42 degrees C and pH 4.5. The recombinant cyprosin B activity is 95% inhibited by pepstatin A, which confirms its aspartic protease nature. The pure recombinant cyprosin B is composed of two subunits, one with 14 and the other with 32 kDa. It exhibits clotting activity, similar to that of the natural enzyme from Cynara cardunculus flowers. The results reported here show that recombinant cyprosin B, the first clotting protease of plant origin produced in a bioreactor, can now be produced in large scale and may constitute a new and efficient alternative to enzymes of animal or fungal origin that are widely used in cheese making. 相似文献
37.
Photoinduced Self‐Assembled Nanostructures and Permanent Polaron Formation in Regioregular Poly(3‐hexylthiophene)
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Newton M. Barbosa Neto Marcia D. R. Silva Paulo T. Araujo Renato N. Sampaio 《Advanced materials (Deerfield Beach, Fla.)》2018,30(16)
Solution processing of conjugated polymers into ordered self‐assembled precursors has attracted great interest in the past years owing to the ability to manipulate their structural and physical properties. Regioregular poly(3‐hexylthiophene) (P3HT) has become the benchmark polymer in this scenario, where ordered lamellar structures significantly improve carrier mobility of the thin films due to increased crystallinity, extended intrachain conjugation, and ordered interchain π‐stacking. Here, a new photoinduced approach is presented for the generation of highly ordered P3HT aggregate structures that is amenable to the use of visible light to control the aggregate formation. Strong intra‐ and interchain interactions in the solution precursors allow for permanent formation of localized and delocalized polarons that are stable for months. Spin‐coated thin films are found to preserve, in part, the morphological and physical properties of the aggregated P3HT solution precursors with high degree of crystallinity and short π‐stack interchain distances. 相似文献
38.
M. A. Maier R. Suresh Babu D. M. Sampaio A. L. F. de Barros 《Journal of Materials Science: Materials in Electronics》2017,28(23):17405-17413
Improvement of the electrical conductivity, specific capacitance and binder-free polyaniline (PANI) interconnected with metal(II) hexacyanoferrate(III) (MHCF) nanocomposites (M?=?Ni, Co) on flexible carbon fibers (CF) were designed in our present research goal. PANI/MHCF/CF nanocomposites were prepared by one-step co-polymerization method. Electrochemical studies like cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy were analyzed. Under the optimized conditions, the nanocomposites demonstrated remarkable electrochemical performances as supercapacitor electrode with outstanding specific capacitances of ~725 F g?1 at a current density of 1 A g?1, and retained ~325 F g?1 even at a high current density of 20 A g?1 in 0.5 M H2SO4?+?0.5 M Na2SO4 solution. The excellent cycling stability with capacitance retention of 80% after 1000 cycles may be a potential electrode material for future supercapacitor when its cycling stability and rate performance are addressed. 相似文献
39.
Moreto Jéferson Aparecido Silva Pedro Henrique Sampaio de Moraes Moura Gabriel da Silva Camila Cristina Ferreira Deusmaque Carneiro da Cunha Thiago Henrique R. Silva Glaura Goulart Rouxinol Francisco de Siervo Abner Gelamo Rogério Valentim 《Journal of Materials Science》2022,57(19):8779-8799
Journal of Materials Science - Flexible self-standing supercapacitor devices (FSSS) have attracted great attention in several areas due to their potential use in a wide range of applications, such... 相似文献
40.
Marcelo Marinho Suzana Sampaio Hermano Moura 《Innovations in Systems and Software Engineering》2018,14(3):157-181
Although it is impossible to predict problems that will occur in software projects, project managers can employ strategies that imbue their projects with greater resilience. Throughout a software project, a series of practices can be established to manage uncertainties. This paper proposes an approach to managing uncertainty in software projects. The approach seems to improve project performance and success. This work is based on the principles of evidence-based software engineering. We conduct an exploratory literature search and a systematic literature review. In addition, we carry out action research in a software development project. Semi-structured interviews were conducted to evaluate and improve this approach. Finally, we held a focus group to evaluate the final proposed approach. The exploratory review helped to characterise the difference between risk and uncertainty. The systematic literature review revealed five methods and 18 practices for reducing uncertainties. The action research applied some of these techniques and investigated whether they contributed to a better uncertainty management. In the semi-structured interviews, practical points of view were added to the approach. This work defines an approach to uncertainty management and describes strategies that allow team members to explicitly formalise and manage uncertainty in software projects. 相似文献