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排序方式: 共有841条查询结果,搜索用时 15 毫秒
1.
Fernando Bento Cunha Karina Torres Pomini Ana Maria de Guzzi Plepis Virgínia da Conceio Amaro Martins Eduardo Gomes Machado Renato de Moraes Marcelo de Azevedo e Souza Munhoz Michela Vanessa Ribeiro Machado Marco Antonio Hungaro Duarte Murilo Priori Alcalde Daniela Vieira Buchaim Rogrio Leone Buchaim Victor Augusto Ramos Fernandes Eliana de Souza Bastos Mazuqueli Pereira Andr Antonio Pelegrine Marcelo Rodrigues da Cunha 《Molecules (Basel, Switzerland)》2021,26(6)
Autologous bone grafts, used mainly in extensive bone loss, are considered the gold standard treatment in regenerative medicine, but still have limitations mainly in relation to the amount of bone available, donor area, morbidity and creation of additional surgical area. This fact encourages tissue engineering in relation to the need to develop new biomaterials, from sources other than the individual himself. Therefore, the present study aimed to investigate the effects of an elastin and collagen matrix on the bone repair process in critical size defects in rat calvaria. The animals (Wistar rats, n = 30) were submitted to a surgical procedure to create the bone defect and were divided into three groups: Control Group (CG, n = 10), defects filled with blood clot; E24/37 Group (E24/37, n = 10), defects filled with bovine elastin matrix hydrolyzed for 24 h at 37 °C and C24/25 Group (C24/25, n = 10), defects filled with porcine collagen matrix hydrolyzed for 24 h at 25 °C. Macroscopic and radiographic analyses demonstrated the absence of inflammatory signs and infection. Microtomographical 2D and 3D images showed centripetal bone growth and restricted margins of the bone defect. Histologically, the images confirmed the pattern of bone deposition at the margins of the remaining bone and without complete closure by bone tissue. In the morphometric analysis, the groups E24/37 and C24/25 (13.68 ± 1.44; 53.20 ± 4.47, respectively) showed statistically significant differences in relation to the CG (5.86 ± 2.87). It was concluded that the matrices used as scaffolds are biocompatible and increase the formation of new bone in a critical size defect, with greater formation in the polymer derived from the intestinal serous layer of porcine origin (C24/25). 相似文献
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3.
N. Euler W. -H. Steeb L. G. S. Duarte I. C. Moreira 《International Journal of Theoretical Physics》1991,30(9):1267-1271
The techniques of invertible point transformations and the Painlevé analysis can be used to construct integrable ordinary differential equations. We compare both techniques for the second Painlevé transcendent. 相似文献
4.
Fabrina R S Bentlin Fábio A Duarte Valderi L Dressler Dirce Pozebon 《Analytical sciences》2007,23(9):1097-1101
This work deals with As determination in marine sediment using ultrasound for sample preparation. It is shown that As can be quantitatively extracted from marine sediment using 20% (v/v) HCl and sonication. The slurry is centrifuged and the analyte is determined in the supernatant by hydride generation atomic absorption spectrometry (HG AAS). A flow injection (FI) system is employed for hydride generation, with 0.5% (m/v) NaBH(4) used as reducdant and a 20% (v/v) HCl used as sample carrier. The limit of quantification is 1.6 microg g(-1) of As, which is based on 800 microl of sample solution and 0.200 g of sample mass in a volume of 50 mL. Certified and non certified marine sediment samples were analyzed; the results were in accordance with the certified or reference values. Speciation analysis by HPLC-ICP-MS showed that As(V) is the only detectable As species present in the supernatant of the centrifuged sample. 相似文献
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7.
O. P. Oliveira Junior J. E. S. Sarkis 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(3):519-526
An analytical procedure was developed to determine the concentration of some elements regarded as trace impurities in nuclear fuel using inductively coupled plasma mass spectrometry (ICPMS) associated to the matrix matching method. The assessment of this approach was carried out using a set of certified reference materials produced by the New Brunswick Laboratory (NBL). Eighteen out of the twenty-four elements in the reference materials could be easily determined. It was found that the mean values for reproducibility and accuracy were 5.0% and 15.0%. The remaining six elements provided mean values of 11.0% and 37.0%, respectively. They could not be adequately determined due to the effects of analyte signal suppression and spectral interference. 相似文献
8.
Bergquist Peter L. Te’o V. S. Junior Gibbs Moreland D. Cziferszky Angela C. E. De Faria Fabricia P. Azevedo Maristela O. Nevalainen K. M. Helena 《Applied biochemistry and biotechnology》2002,98(1-9):165-176
Cost-effective production of enzymes for industrial processes makes the appropriate selection of the host-vector expression
system critical. We have developed two systems for the bulk production of bleaching enzymes from thermophiles. Kluyveromyces lactis has been developed as a secretion host employing expression vectors based on the 2μ-like plasmid pKD1 of Kluyveromyces drosophilarium. Our second system involves the filamentous fungus Trichoderma reesei. Fusion and nonfusion vectors have been constructed using the strong cellobiohydrolase 1 (cbh1) promoter. The KEX2 protease cleavage site and a 6 × HIS-tag have been incorporated to facilitate both cleavage and purification
of the mature foreign proteins. 相似文献
9.
S.A.Vieira Filho L.P. Duarte G.D.F. Silva O.W. Howarth I.S. Lula 《Helvetica chimica acta》2003,86(10):3445-3449
3β‐(Stearyloxy)olean‐12‐ene was isolated from a hexane extract of Austroplenckia populnea Reiss (Celastraceae) leaves. The structure was solved by means of quantitative 13C‐NMR, HMBC, HMQC, COSY, NOESY, and NOE difference spectra. The mass spectrum showed an [M+1]+ ion peak at m/z 693, and the molecular formula C48H84O2 was confirmed by combustion analysis. 相似文献
10.
M. Costa-Ferreira A. Dias C. Maximo M. J. Morgado G. Sena-Martins J. Cardoso Duarte 《Applied biochemistry and biotechnology》1994,44(3):231-242
Production of xylanolytic enzymes by anAspergillus niger CCMI 850 isolate was investigated in batch cultures. The effect of the composition of a fermentation medium that did not
include chemical inducers, on β-xylanase, β-xylosidase, α-l-arabinofuranosidase, and total cellulase activity was studied. With 4% xylan as the carbon source, about 65 U/mL of β-xylanase
was obtained, whereas the total cellulase activity was undetectable, under the specified conditions. This β-xylanase activity
represents the highest reported for a wild-type strain ofA. niger. The effect of pH and temperature on the activity of β-xylanase was studied. Partial characterization of the β-xylanase showed
that with insoluble birchwood as substrate theK
m
andV
max were 0.3 mM and 19 μmol/min, respectively. Aspects of using the crude β-xylanase preparation for applications in the pulp and paper industry
were discussed. 相似文献