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‣ Evaluation of the cytocompatibility of mixed bovine bone

Takamori,Esther Rieko; Figueira,Eduardo Aleixo; Taga,Rumio; Sogayar,Mari Cleide; Granjeiro,José Mauro
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 Português
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Treatment of bovine bone with peroxides and chaotropic agents aims to obtain an acellular bone matrix that is able to maintain the collagen-apatite complex and a higher mechanical resistance, a mixed biomaterial hereby named mixed bovine bone (MBB). The purpose of this study was to evaluate the cytocompatibility of MBB and cell-MBB interaction. Cell morphology, number of viable cells, ability to reduce methyltetrazolium and to incorporate neutral red upon exposure to different concentrations of the hydrosoluble extract of MBB were assessed in Balb-c 3T3 cells according to ISO 10993-5 standard. The interaction between cells and MBB surface was evaluated by scanning electron microscopy. The water-soluble MBB extracts were cytotoxic and led to cell death possibly due to its effect on mitochondrial function and membrane permeability. Cells plated directly onto the MBB did not survive, although after dialysis and material conditioning in DMEM + 10% FCS, the cells adhered and proliferated onto the material. It may be concluded that, in vitro, water-soluble MBB extracts were cytotoxic. Nevertheless, MBB cytotoxic effect was reverted by dialysis resulting in a material that is suitable for cell based-therapy in the bioengineering field.

‣ The evolution and developments of immunosensors for health and environmental monitoring: problems and perspectives

Bojorge Ramírez,N.; Salgado,A. M.; Valdman,B.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 Português
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‣ Scientific use of the finite element method in Orthodontics

Knop,Luegya; Gandini Jr.,Luiz Gonzaga; Shintcovsk,Ricardo Lima; Gandini,Marcia Regina Elisa Aparecida Schiavon
Fonte: Dental Press International Publicador: Dental Press International
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 Português
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INTRODUCTION: The finite element method (FEM) is an engineering resource applied to calculate the stress and deformation of complex structures, and has been widely used in orthodontic research. With the advantage of being a non-invasive and accurate method that provides quantitative and detailed data on the physiological reactions possible to occur in tissues, applying the FEM can anticipate the visualization of these tissue responses through the observation of areas of stress created from applied orthodontic mechanics. OBJECTIVE: This article aims at reviewing and discussing the stages of the finite element method application and its applicability in Orthodontics. RESULTS: FEM is able to evaluate the stress distribution at the interface between periodontal ligament and alveolar bone, and the shifting trend in various types of tooth movement when using different types of orthodontic devices. Therefore, it is necessary to know specific software for this purpose. CONCLUSIONS: FEM is an important experimental method to answer questions about tooth movement, overcoming the disadvantages of other experimental methods.

‣ Evaluation of the force applied by the tongue and lip on the maxillary central incisor tooth

Valentim,Amanda Freitas; Furlan,Renata Maria Moreira Moraes; Perilo,Tatiana Vargas de Castro; Berbert,Monalise Costa Batista; Motta,Andréa Rodrigues; Casas,Estevam Barbosa de Las
Fonte: Sociedade Brasileira de Fonoaudiologia Publicador: Sociedade Brasileira de Fonoaudiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 Português
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PURPOSE: To describe the development and testing of a system that measures forces exerted by the tongue and upper lip on a tooth during rest and during swallowing. METHODS: Twenty-eight subjects, aged 19-31 years (mean: 23.2 years) were submitted to measurement of forces exerted by the upper lip and tongue on the maxillary right central incisor tooth. Flexiforce resistive sensors were fixed on the labial and lingual surfaces of the tooth. They were connected to an amplifier circuit and a data acquisition board for processing and transmitting information to a computer. RESULTS: At rest, the tongue force on the tooth was 0.00±0.00 N and the lip force on tooth was 0.02±0.02 N. The difference between them was significant. During swallowing, the values were 0.31±0.38 N and 0.15±0.14 N, for the tongue and lip, respectively. This difference was not significant. CONCLUSION: At rest, the lip exerts a larger force than the tongue on the maxillary right central incisor tooth. During swallowing, there was no difference between lip and tongue force on the tooth.

‣ Modification of the substrate specificity of an acyl-acyl carrier protein thioesterase by protein engineering.

Yuan, L; Voelker, T A; Hawkins, D J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 07/11/1995 Português
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The plant acyl-acyl carrier protein (ACP) thioesterases (TEs) are of biochemical interest because of their roles in fatty acid synthesis and their utilities in the bioengineering of plant seed oils. When the FatB1 cDNA encoding a 12:0-ACP TE (Uc FatB1) from California bay, Umbellularia californica (Uc) was expressed in Escherichia coli and in developing oilseeds of the plants Arabidopsis thaliana and Brassica napus, large amounts of laurate (12:0) and small amounts of myristate (14:0) were accumulated. We have isolated a TE cDNA from camphor (Cinnamomum camphorum) (Cc) seeds that shares 92% amino acid identity with Uc FatB1. This TE, Cc FatB1, mainly hydrolyzes 14:0-ACP as shown by E. coli expression. We have investigated the roles of the N- and C-terminal regions in determining substrate specificity by constructing two chimeric enzymes, in which the N-terminal portion of one protein is fused to the C-terminal portion of the other. Our results show that the C-terminal two-thirds of the protein is critical for the specificity. By site-directed mutagenesis, we have replaced several amino acids in Uc FatB1 by using the Cc FatB1 sequence as a guide. A double mutant, which changes Met-197 to an Arg and Arg-199 to a His (M197R/R199H), turns Uc FatB1 into a 12:0/14:0 TE with equal preference for both substrates. Another mutation...

‣ Isolation and identification of short nucleotide sequences that affect translation initiation in Saccharomyces cerevisiae

Zhou, Wei; Edelman, Gerald M.; Mauro, Vincent P.
Fonte: The National Academy of Sciences Publicador: The National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
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In previous studies, we demonstrated the sufficiency of short nucleotide sequences to facilitate internal initiation of translation in mammalian cells. By using a selection methodology, we have now identified comparable sequences in Saccharomyces cerevisiae. For these studies, a library of constructs expressing dicistronic mRNAs with the HIS3 gene as the second cistron and 18 random nucleotides in the intercistronic region was introduced into a yeast strain in which the endogenous HIS3 gene was deleted. Untransformed cells or those containing the parent construct failed to grow on medium lacking histidine. Intercistronic sequences recovered from cells that did grow were evaluated by using various criteria. Fifty-six of the 18-nt sequences (≈1/400,000) functioned as synthetic internal ribosome entry sites (IRESes). The 14 most active sequences allowed growth in the presence of 0.1–0.6 mM 3-amino-1,2,4-triazole, a competitive inhibitor of the HIS3 gene product. In addition, eight sequences were identified that were not IRESes, but that enhanced HIS3 expression by an alternative mechanism that depended on the 5′ end of the mRNA and appeared to involve either shunting or reinitiation. Comparisons among the 56 selected IRESes identified eight significant sequence matches containing up to 10 nucleotides. Many of the selected sequences also contained extensive complementary matches to yeast 18S rRNA...

‣ Diazotrophic Community Structure and Function in Two Successional Stages of Biological Soil Crusts from the Colorado Plateau and Chihuahuan Desert

Yeager, Chris M.; Kornosky, Jennifer L.; Housman, David C.; Grote, Edmund E.; Belnap, Jayne; Kuske, Cheryl R.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2004 Português
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The objective of this study was to characterize the community structure and activity of N2-fixing microorganisms in mature and poorly developed biological soil crusts from both the Colorado Plateau and Chihuahuan Desert. Nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the Colorado Plateau site and Chihuahuan Desert site, respectively. Analysis of nifH sequences by clone sequencing and the terminal restriction fragment length polymorphism technique indicated that the crust diazotrophic community was 80 to 90% heterocystous cyanobacteria most closely related to Nostoc spp. and that the composition of N2-fixing species did not vary significantly between the poorly developed and mature crusts at either site. In contrast, the abundance of nifH sequences was approximately 7.5 times greater (per microgram of total DNA) in mature crusts than in poorly developed crusts at a given site as measured by quantitative PCR. 16S rRNA gene clone sequencing and microscopic analysis of the cyanobacterial community within both crust types demonstrated a transition from a Microcoleus vaginatus-dominated, poorly developed crust to mature crusts harboring a greater percentage of Nostoc and Scytonema spp. We hypothesize that ecological factors...

‣ A bubble-driven microfluidic transport element for bioengineering

Marmottant, Philippe; Hilgenfeldt, Sascha
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
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Microfluidics typically uses channels to transport small objects by actuation forces such as an applied pressure difference or thermocapillarity. We propose that acoustic streaming is an alternative means of directional transport at small scales. Microbubbles on a substrate establish well controlled fluid motion on very small scales; combinations (“doublets”) of bubbles and microparticles break the symmetry of the motion and constitute flow transport elements. We demonstrate the principle of doublet streaming and describe the ensuing transport. Devices based on doublet flow elements work without microchannels and are thus potentially cheap and highly parallelizable.

‣ Insulin-like Growth Factor I Controls Adhesion Strength Mediated by α5β1 Integrins in Motile Carcinoma Cells

Lynch, Laura; Vodyanik, Pavel I.; Boettiger, David; Guvakova, Marina A.
Fonte: The American Society for Cell Biology Publicador: The American Society for Cell Biology
Tipo: Artigo de Revista Científica
Publicado em /01/2005 Português
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One of the intriguing questions regarding cell motility concerns the mechanism that makes stationary cells move. Here, we provide the first physical evidence that the onset of breast cancer cell motility in response to insulin-like growth factor I (IGF-I) correlates with lowering of adhesion strength from 2.52 ± 0.20 to 1.52 ± 0.13 μdynes/μm2 in cells attached to fibronectin via α5β1 integrin. The adhesion strength depends on the dose of IGF-I and time of IGF-I treatment. Weakening of cell-matrix adhesion is blocked significantly (p < 0.01) by the catalytically inactive IGF-I receptor (IGF-IR) and the phosphoinositide 3-kinase (PI-3 kinase) inhibitor LY-294002, but it is unaffected by mitogen-activated protein kinase kinase inhibitor UO-126 and Src kinase inhibitor PP2. Sustained blockade of Rho-associated kinase (ROCK) with Y-27632 down-regulates adhesion strength in stationary, but not in IGF-I-treated, cells. Jasplakinolide, a drug that prevents actin filament disassembly, counteracts the effect of IGF-I on integrin-mediated cell adhesion. In the absence of growth factor signaling, ROCK supports a strong adhesion via α5β1 integrin, whereas activation of the IGF-IR kinase reduces cell-matrix adhesion through a PI-3K-dependent...

‣ Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

Hipp, Jason; Atala, Anthony
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 08/12/2004 Português
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Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell is transferred into an enucleated oocyte), and parthenogenesis (oocyte is activated and stimulated to divide), permit extraction of pluripotent embryonic stem cells, and offer a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy. The present article reviews recent progress in tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure.

‣ Review of "Understanding the Human Machine, A Primer for Bioengineering" by Max E. Valentinuzzi

Hsiai, Tzung K
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 10/02/2005 Português
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‣ Review of "Dynamics of the Vascular System" by John K-J Li. Series on Bioengineering & Biomedical Engineering – Vol. 1

Anbar, Michael
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 28/02/2005 Português
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‣ Bioengineering, Thermal Physiology and Comfort

Crockford, G W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1981 Português
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‣ Articular gelling in osteoarthrosis--a bioengineering study.

Wright, V; Goddard, R; Dawson, D; Longfield, M D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1970 Português
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‣ Some Considerations of Bioengineering from a Microscopic Viewpoint1

Donovick, Richard
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1960 Português
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‣ Bioengineering and Fermentation

Gaden, Elmer L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1960 Português
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‣ A catalyst of the bioengineering field plans its farewell

Bloom, Stacie
Fonte: American Society for Clinical Investigation Publicador: American Society for Clinical Investigation
Tipo: Artigo de Revista Científica
Publicado em 01/08/2005 Português
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‣ Farm animal genomics and informatics: an update

Fadiel, Ahmed; Anidi, Ifeanyi; Eichenbaum, Kenneth D.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Farm animal genomics is of interest to a wide audience of researchers because of the utility derived from understanding how genomics and proteomics function in various organisms. Applications such as xenotransplantation, increased livestock productivity, bioengineering new materials, products and even fabrics are several reasons for thriving farm animal genome activity. Currently mined in rapidly growing data warehouses, completed genomes of chicken, fish and cows are available but are largely stored in decentralized data repositories. In this paper, we provide an informatics primer on farm animal bioinformatics and genome project resources which drive attention to the most recent advances in the field. We hope to provide individuals in biotechnology and in the farming industry with information on resources and updates concerning farm animal genome projects.

‣ A user-designed resuscitation unit.

MacVicar, S M; Watts, M P; Watt, C S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1986 Português
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Prior to the commissioning of the Phase I redevelopment of Glasgow Royal Infirmary, the need for the development of a new type of resuscitation trolley had been identified by a liaison group consisting of medical, nursing and scientific staff which had been set up to collaborate on the selection and specification of clinical equipment. A design study involving the liaison group and the Product Design Section of the Glasgow School of Art was, therefore, undertaken. This resulted in a basic design which was built in prototype form by the Department of Clinical Physics and Bioengineering for hospital trials. The unit was later taken over commercially.

‣ Cytosolic Triacylglycerol Biosynthetic Pathway in Oilseeds. Molecular Cloning and Expression of Peanut Cytosolic Diacylglycerol Acyltransferase1[W]

Saha, Saikat; Enugutti, Balaji; Rajakumari, Sona; Rajasekharan, Ram
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /08/2006 Português
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Triacylglycerols (TAGs) are the most important storage form of energy for eukaryotic cells. TAG biosynthetic activity was identified in the cytosolic fraction of developing peanut (Arachis hypogaea) cotyledons. This activity was NaF insensitive and acyl-coenzyme A (CoA) dependent. Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final step in TAG biosynthesis that acylates diacylglycerol to TAG. Soluble DGAT was identified from immature peanuts and purified by conventional column chromatographic procedures. The enzyme has a molecular mass of 41 ± 1.0 kD. Based on the partial peptide sequence, a degenerate probe was used to obtain the full-length cDNA. The isolated gene shared less than 10% identity with the previously identified DGAT1 and 2 families, but has 13% identity with the bacterial bifunctional wax ester/DGAT. To differentiate the unrelated families, we designate the peanut gene as AhDGAT. Expression of peanut cDNA in Escherichia coli resulted in the formation of labeled TAG and wax ester from [14C]acetate. The recombinant E. coli showed high levels of DGAT activity but no wax ester synthase activity. TAGs were localized in transformed cells with Nile blue A and oil red O staining. The recombinant and native DGAT was specific for 1...