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A Bidimensional Finite Element Study of Crack Propagation in Austempered Ductile Iron

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Computers, Materials & Continua 2023年第11期77卷 1411-1424页

作者： gustavo von Zeska de França Roberto Luís de Assumpção Marco Antonio Luersen Carlos henrique da Silva Department of Mechanical Engineering Federal University of Technology–ParanáCuritiba81280-340Brazil

Austempered ductile iron(ADI)is composed of an ausferritic matrix with graphite nodules and has a wide range of applications because of its high mechanical strength,fatigue resistance,and wear resistance compared to other cast *** amount and size of the nodules can be controlled by the chemical composition and austenitizing *** the nodules have lower stiffness than the matrix and can act as stress concentrators,they influence crack ***,the crack propagation mechanism in ADI is not yet fully *** this study,we describe a numerical investigation of crack propagation in ADIs subjected to cyclic *** numerical model used to calculate the stress intensity factors in the material under the given conditions is built with the aid of Abaqus commercial finite element *** crack propagation routine,which is based on the Paris law,is implemented in *** results of the simulation show that the presence of a nodule generates a shear load on the crack ***,even under uniaxial tensile loading,the presence of the nodule yields a non-zero stress intensity factor in mode II,resulting in a deviation in the crack propagation *** is the primary factor responsible for changing the crack propagation direction towards the *** the parameters,for example,increasing the nodule size or decreasing the distance between the nodule and crack tip,can intensify this *** simulations comparing two different ADIs with the same graphite fraction area,the crack in the material with more nodules reaches another nodule in a shorter propagation time(or shorter number of cycles).This suggests that the high fatigue resistance observed in ADIs may be correlated with the number of nodules intercepted by a crack and the additional energy required to nucleate new *** summary,these findings contribute to a better understanding of crack propagation in ADIs,provide insights into the relationship between the presence

关键词： Austempered ductile iron(ADI) fatigue crack propagation graphite nodule

Histological Assessment of Bone Regeneration in the Maxilla with Homologous Bone Graft:A Feasible Option for Maxillary Bone Reconstruction

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Journal of Renewable Materials 2024年第1期12卷 131-148页

作者： Sergio henrique Gonçalves Motta Ana Paula Ramos Soares Juliana Campos Hasse Fernandes gustavo Vicentis Oliveira Fernandes Graduate Center of Faculdade Redentor CLIVORio de JaneiroBrazil Periodontics and Oral Medicine Department University of Michigan School of DentistryAnn ArborMI48109USA Centre for Interdisciplinary Research in Health(CIIS) Universidade Católica PortuguesaViseu3504-505Portugal

Bone biomaterials have been increasingly used to reconstruct maxillary atrophic ***,the aim of this study was to evaluate bone reconstruction in the maxilla using a homologous cortico-cancellous FFB(lyophilized)graft and verify its *** individuals were included from 2014 to *** first surgery was performed to install homologous bone blocks in the *** period of the second intervention varied between 5 months and 15 days to 11 months(≈7.93 months).The biopsies were taken from the central region of the matured graft during the surgery for implant *** patients presented clinical and radiographic conditions for the installation of dental *** was a 100%of survival *** histological assessment showed that the homologous block bone graft was an osteoconductive biomaterial,with connective tissue present,and newly formed bone juxtaposed on its *** were bone trabeculae with osteocytes and active osteoblasts with connective tissue in the mineralization process;the remodeling process can be found through the reverse lines.A limited focus of necrosis with fibrosis was detected,with small resorption and areas of inflammatory infiltrate,but without clinical *** homologous block bone graft can be considered a feasible option to substitute the autogenous bone graft(gold standard),with predictable clinical and favorable histological *** patients had a shorter surgical period,low morbidity,and an unlimited amount of biomaterial available at an accessible cost.

关键词： Regeneration bone graft histology homologous allogenous autogenous

Diagnostic Value of Hepatic Enzymes, Triglycerides and Serum Proteins for the Detection of Hepatic Lipidosis in Chelonoidis carbonaria in Captivity

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Journal of Life Sciences 2014年第8期8卷 633-639页

作者： gustavo henrique Pereira Dutra Aquario Municipal de Santos Avenida Bartolomeu de Gusmao s/n Ponta da Praia-Santos-SP 11030-500 Brazil

Hepatic lipidosis is a common lesion in chelonians and may be related with vitellogenesis, hyperparathyroidism, follicular stasis, fatty diets or lacking nutrients, sedentary life and obesity, bacterial toxins in liver and starvation. Clinical signs are unspecific. Routine biochemical tests don＇t have specificity and it is better defined through biopsy. The objective was evaluated the biochemical hepatic profile of red footed tortoises （Chelonoidis carbonaria） with the histopathological findings of lipidosis by laparoscopic biopsy. Samples of blood were collected for biochemistry of thirty-six animals from two different groups, twenty animals from a zoo and sixteen from a breeder. The animals were submitted to liver biopsy by videolaparoscopy. Three fragments were collected, two of them were processed by histology and one went to electron microscopy. Nineteen tortoises from the zoo had lipidosis in laparoscopy and macrovesicular degeneration. Fifteen tortoises from the breeder had microvesicular degeneration. The diagnosis of steatosis was confirmed by electron microscopy. There was no statistical difference of aspartate aminotransferase levels between the two groups; however there was significant difference of triglycerides levels. The enzymatic activity of transaminases is not related to the histological grading of lipidosis in tortoises, however triglycerides levels are higher in animals with more severe gradation.

关键词： Biopsy steatosis liver Chelonoidis enzymes.

Determinant variables on the isotopic values of particulate organic matter in a neotropical floodplain

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Journal of Oceanology and Limnology 2024年第4期42卷 1173-1185页

作者： Vinícius de ANDRADE URBANO Matheus MAXIMILIAN RATZ SCOARIZE gustavo henrique ZAIA ALVES Driele DELANIRA-SANTOS Marcela da SILVA CAETANO Evanilde BENEDITO Departamento de Biologia(DBI) Laboratório de Ecologia EnergéticaUniversidade Estadual de Maringá(UEM)Maringá87020-900Brasil Programa de Pós-graduação em Ecologia de Ambientes Aquáticos Continentais(PEA) Universidade Estadual de Maringá(UEM)Maringá87020-900Brasil Departamento de Biologia Geral Universidade Estadual de Ponta Grossa(UEPG)Campus UvaranasPonta Grossa 84030-900Brasil Australian Rivers Institute(ARI) Griffith UniversityNathan QLD 4111Australia

Particulate organic matter(POM)is an important energy source for aquatic consumers,understanding its origin and composition is essential for understanding the energetic dynamics of aquatic *** aim of this study was to analyze the relationship between POM and phytoplankton(isotopic values and chlorophyll concentration)and abiotic variables during dry and rainy *** was conducted in rivers and lagoons in the floodplain of the Upper Paraná*** found a greater difference in ^(δ13)C values of POM between sampling points than between seasons,indicating that the composition of regional sources influences the composition of POM more than dry and rainy *** addition,the concentration of chlorophyll during the dry season was positively correlated with ^(δ13)C values during that rainy ***,we found a relationship between factors limiting the growth of phytoplankton and ^(δ13)C values of POM,such as phosphate ions,indicating that variables that regulate phytoplankton growth tend to influence the composition of POM in river ***,maintaining the variables that regulate the phytoplankton community is of fundamental importance for the composition of POM,an important energy source in aquatic environments.

关键词： freshwater wetland stable isotopes food web subtropical environment

Characterization of blood flow and the effects of exogenous estradiol benzoate on residual follicles formed after ultrasound-guided transvaginal follicle aspiration in cattle

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Journal of Animal Science and Biotechnology 2017年第1期8卷 51-56页

作者： Alberto Mansur Ghetti Luiz gustavo Bruno Siqueira Eduardo Kenji Nunes Arashiro Miller Pereira Palhao Felipe Zandonadi Brandao Joao henrique Moreira Viana Universidade Federal Fluminense Niteroi RJ 24230-340 Brazil Embrapa Gado de Leite Juiz de Fora MG 36038-330 Brazil Universidade Jose do Rosario Vellano Alfenas MG 37130-000 Brazil Embrapa Recursos Geneticos e Biotecnologia PqEB Av. W5 N Brasilia DF 70770-917 Brazil

Background： Removal of the follicular content by ultrasound-guided transvaginal follicle aspiration（TVFA） may fail to induce immediate atresia and loss of function, resulting in the occurrence of residual follicles（RF）. The aims of this study were to characterize the blood flow in RF and to determine the effects of the treatment with estradiol benzoate on RF fate. Lactating, cyclic Holstein-Gir crossbred cows were used. In Experiment 1, follicular wave emergence（D0） was synchronized in cows（n = 10） and follicular growth was then monitored by transrectal ultrasonography from D0 to D8, followed by TVFA of the largest follicle present on the ovaries 24 h later. Color Doppler ultrasound imaging was used to examine blood flow on the follicular wall, which was recorded immediately before and every 12 h after TVFA, up to 72 h. In experiment 2, cows（n = 22） were randomly allocated to receive either 2 mL of saline i.m.（Control group, n = 11） or 2 mL estradiol benzoate i.m.（EB group, n = 11）immediately after TVFA. Ovaries were scanned every 12 h to confirm the presence and to measure the diameter of RF. The contents of the RF, if present, were collected 72 h after the first TVFA, using the same aspiration *** fluid from original follicles and RF were stored at-20 °C until hormonal ***： In Experiment 1, there was no reduction（P 〉 0.05） of blood flow in the remaining follicle walls after TVFA and maximum blood flow values were observed at 49.5 ± 19.7 h post-TVFA. In Experiment 2, formation of RF after TVFA was proportionally similar between Controls（5/9） and EB（5/10） cows. Also, RF diameter did not differ between groups（P 〉 0.05）. Nonetheless, the content of RF from cows in the EB group had lower（P = 0.0004）estradiol（E2） concentration and lower（P = 0.0005） E2：P4 ratio compared with ***： In conclusion, 1） the persistence of vascularization in the remaining follicle wall may contribute to the formation of RF after follicle aspiration,

关键词： Doppler Ovary Ovum pick-up Steroidogenesis Vascularization

Glutamine prevents oxidative stress in a model of mesenteric ischemia and reperfusion

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World Journal of Gastroenterology 2014年第32期20卷 11406-11414页

作者： Gilmara Pandolfo Zabot gustavo Franco Carvalhal Norma Possa Marroni Renata Minuzzo Hartmann Vinícius Duval da Silva henrique Sarubbi Fillmann Department of Surgery School of Medicine Pontifical Catholic University of Rio Grande do Sul Porto Alegre RS 90610-000 Brazil Department of Gastroenterology School of Medicine Federal University of Rio Grande do Sul Porto Alegre RS 90035-903 Brazil Department of Pathology School of Medicine Pontifical Catholic University of Rio Grande do SulPorto Alegre RS 90610-000 Brazil

AIM: To evaluate preventative effects of glutamine in an animal model of gut ischemia/reperfusion (I/R).

关键词： Ischemia-reperfusion Glutamine Lipid peroxidation Superoxide dismutase Nuclear factor-kappa beta Interleukin 6

Biochar influences the cane fields’microbiota and the development of pre-sprouted sugarcane seedlings

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Waste Disposal and Sustainable Energy 2023年第1期5卷 75-88页

作者： Bruna Cristina Pinto Adriana Barboza Alves Osania Emerenciano Ferreira gustavo henrique Gravatim Costa Magno Andréde Oliveira Augusto Cesar da Silva Bezerra Alan Rodrigues Teixeira Machado Postgraduate Program in Environmental Sciences State University of Minas GeraisFrutal UnityFrutalMinas Gerais38202-436Brazil Department of Agricultural and Biological Sciences State University of Minas GeraisFrutal UnityFrutalMinas Gerais38208-436Brazil Postgraduate Program in Geotechnical Engineering Federal University of Ouro PretoOuro PretoMinas Gerais35400-000Brazil Department of Transport Engineering Federal Center for Technological Education of Minas GeraisBelo HorizonteMinas Gerais30421-169Brazil Department of Exact Sciences State University of Minas GeraisJoão Monlevade UnityJoão MonlevadeMinas Gerais35930-314Brazil

This research investigates the soil conditioning effect of sugar cane fields with biochar produced from sugarcane *** influence on the physicochemical and microbiological conditions of the soil and the agronomic performance of sugarcane seedlings was *** this end,the biochar from sugarcane bagasse was produced by pyrolysis in a double drum oven and mixed with soil at rates of 0,1%,3%,and 5%(in weight).The experiment was installed in a greenhouse with two evaluation periods(30 days and 60 days)and five *** pot received a pre-sprouted cane seedling,and the analysis of colony-forming units(bacteria and fungi),physicochemical characteristics of the soil,and growth and development of sugarcane were performed per *** biochar showed a high fixed carbon content(72%)and a specific surface area estimated by the adsorption of methylene blue of 50 m2 g−***,its structure is porous and contains important nutrients(e.g.,CaO,K2O,and P2O5).In the periods evaluated,the applications of the 3%and 5%(in weight)rates of biochar reduced most of the soil fertility ***,the chemical analyses indicated that the sugarcane field soil collected already possessed high *** microbiota was influenced,but only the application of the 3%(in weight)rate at 60 days after planting showed a significant positive effect on the number of bacteria forming units,with an increase of approximately 385%.On the other hand,no significant positive effect on sugarcane development was ***,biochar application in high-fertility sugarcane plantation soil did not result in gains for sugarcane development in the periods evaluated.

关键词： Soil Biometry Microbiology Double drum oven Biochar

Glutamine prevents oxidative stress in a model of portal hypertension

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World Journal of Gastroenterology 2017年第25期23卷 4529-4537页

作者： Gilmara Pandolfo Zabot gustavo Franco Carvalhal Norma Possa Marroni Francielli Licks Renata Minuzzo Hartmann Vinícius Duval da Silva henrique Sarubbi Fillmann Department of Surgery School of MedicinePontifical Catholic University of Rio Grande do Sul Department of Gastroenterology School of MedicineFederal University of Rio Grande do Sul Department of Pathology School of MedicinePontifical Catholic University of Rio Grande do Sul

To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL). METHODSMale Wistar rats were housed in a controlled environment and were allowed access to food and water ad libitum. Twenty-four male Wistar rats were divided into four experimental groups: (1) control group (SO) - rats underwent exploratory laparotomy; (2) control + glutamine group (SO + G) - rats were subjected to laparotomy and were treated intraperitoneally with glutamine; (3) portal hypertension group (PPVL) - rats were subjected to PPVL; and (4) PPVL + glutamine group (PPVL + G) - rats were treated intraperitoneally with glutamine for seven days. Local injuries were determined by evaluating intestinal segments for oxidative stress using lipid peroxidation and the activities of glutathione peroxidase (GPx), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) after PPVL. RESULTSLipid peroxidation of the membrane was increased in the animals subjected to PH (P 0.05). The activity of the antioxidant enzyme GTx was decreased in the gut of animals subjected to PH compared with that in the control group of animals not subjected to PH (P 0.05). At least 10 random, non-overlapping images of each histological slide with 200 × magnification (44 pixel = 1 μm) were captured. The sum means of all areas, of each group were calculated. The mean areas of eNOS staining for both of the control groups were similar. The PPVL group showed the largest area of staining for eNOS. The PPVL + G group had the second highest amount of staining, but the mean value was much lower than that of the P

关键词： Portal hypertension Endothelial nitric oxide synthase Glutamine Glutathione peroxidase Inducible nitric oxide synthase Lipid peroxidation

Intravascular Access in Chelonia mydas and Dermochelys coriacea Using the Seldinger Technique U Itrasou nd-Guided

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Journal of Life Sciences 2014年第5期8卷 385-393页

作者： gustavo henrique Pereira Dutra Fálbio Futema Flávio Augusto Marques dos Santos Cristiane Lassalvia Aquário Municipal de Santos Av. Bartolomeu de Gusmao s/n. Ponta da Praia. Santos-SP 11030-500 Brazil Universidade de Guarulhos Av. Anton Philips 01 Vila Herminia Guarulhos 07030-010 Brazil Universidade Anhembi Morumbi Rua Casa do Ator 294. Vila Olimpia 04546-000-Sao Paulo SP Brasil

Strand-ed turtles need fluid parenterally. The jugular access is best for the maintenance and patency of the catheter. The Seldinger technique guided by ultrasound seems to be the safest for catheter insertion. Five juveniles Chelonia mydas with fibropapillomatosis and an adult male leatherback turtle （Dermochelys coriacea） with altered buoyancy were sent to Santos Municipal Aquarium for rehabilitation. Turtles underwent catheterization of the jugular vein using the Seldinger technique with central venous polyurethane catheter monolumen 14 G to Dermochelys and 18 G for Chelonia, guided by ultrasound with 10 MHz transducer catheters were sutured to the skin and animals were subjected to fluid. In all turtles, the catheters were patency and were well established. There were no granulomatous reactions or related infections. The Dermochelys improved clinically after fluid resuscitation, and the catheter was removed one week after. In one Chelonia excision was 21% of its weight in tumors, and the animals received colloid catheter by enabling the mitigation of bleeding due to removal. The use of ultrasonography has enabled monitoring of all access as the patency of the catheter and fluid diffusivity.

关键词： Sea turtles Chelonia Dermochelys ultrassonography Seldinger technique.