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Administration of cannabidiol and imipramine induces antidepressant-like effects in the forced swimming test and increases brain-derived neurotrophic factor levels in the rat amygdala

REUS, Gislaine Z.; STRINGARI, Roberto B.; RIBEIRO, Karine F.; LUFT, Tatiana; ABELAIRA, Helena M.; FRIES, Gabriel R.; AGUIAR, Bianca W.; KAPCZINSKI, Flavio; HALLAK, Jaime E.; ZUARDI, Antonio W.; CRIPPA, Jose A.; QUEVEDO, Joao
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.91%
Objective: Cannabidiol is a chemical constituent from Cannabis sativa and it has multiple mechanisms of action, including antidepressant effects. The main objective of the present study was to evaluate behavioural and molecular effects induced by administration of cannabidiol and imipramine in rats. Methods: In the present study, rats were acutely or chronically treated for 14 days once a day with saline, cannabidiol (15, 30 and 60 mg/kg) or imipramine (30 mg/kg) and the animals behaviour was assessed in forced swimming and open-field tests. Afterwards, the prefrontal cortex, hippocampus and amygdala brain-derived neurotrophic factor (BDNF) levels were assessed by enzyme-linked immunosorbent sandwich assay. Results: We observed that both acute and chronic treatments with imipramine at the dose of 30 mg/kg and cannabidiol at the dose of 30 mg/kg reduced immobility time and increased swimming time; climbing time was increased only with imipramine at the dose of 30 mg/kg, without affecting locomotor activity. In addition, chronic treatment with cannabidiol at the dose of 15 mg/kg and imipramine at the dose of 30 mg/kg increased BDNF levels in the rat amygdala. Conclusion: In conclusion, our results indicate that cannabidiol has an antidepressant-like profile and could be a new pharmacological target for the treatment of major depression.; CNPq-Brazil; FAPESP-Brazil; FAPESC-Brazil; Instituto Cerebro e Mente-Brazil; UNESC-Brazil; CAPES; THC-Pharm (Frankfurt...

O sanduíche baguncinha nas ruas de Cuiabá - MT: avaliação de intervenção educativa; The baguncinha sandwich in the streets of Cuiaba, MT - Brazil: education intervention avaliation

Bezerra, Aida Couto Dinucci
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/06/2007 PT
Relevância na Pesquisa
26.29%
Introdução. O comércio de baguncinha, sanduíche típico da região metropolitana de Cuiabá - MT é fonte de renda no mercado informal e alternativa de alimentação fora de casa. A vigilância sanitária tem problemas estruturais e financeiros para a fiscalização enquanto os organismos de saúde pública recomendam a capacitação dos manipuladores. Objetivo. Avaliar a eficácia de uma intervenção educativa na representação social e na prática de manipuladores de sanduíche baguncinha. Método. Foram pesquisados 35 pontos de venda, divididos em grupo controle e teste, antes e depois de intervenção educativa. Foram observadas as condições de higiene ambiental e pessoal por meio de check list e realizadas análises microbiológicas e medição de temperatura interna do sanduíche. Por meio de entrevista semi-estruturada foram coletados dados representacionais e comportamentais relativos à manipulação segura de alimentos. Os depoimentos foram tratados pela técnica do discurso do sujeito coletivo e os dados comportamentais pela estatística paramétrica. A análise dos dados representacionais e comportamentais foi baseada na triangulação de teorias educativas. Resultados. As condições de higiene pessoal e ambiental se mostraram precárias nos pontos de venda. As mãos dos manipuladores apresentaram altos índices de contaminação microbiológica. Os sanduíches estavam impróprios para consumo em 31...

Estudo do comportamento vibro-acústico de materiais compósitos e estruturas sanduíche para aplicações em ensaios não destrutivos; A study on the vibro-acoustic behavior of composite materials and sandwich structures focusing on applications in nondestructive evaluation

Tourinho, André Miazaki da Costa
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Dissertação
POR
Relevância na Pesquisa
26.35%
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2013.; O uso de materiais compósitos e estruturas sanduíche vem crescendo com o passar do tempo. Este crescimento gera, por sua vez, uma demanda por formas de se detectar defeitos e danos, e avaliar a integridade de estruturas feitas com esses materiais de maneira prática e confiável. Neste contexto, o presente trabalho busca iniciar o desenvolvimento de novos métodos de ensaio não destrutivo de materiais compósitos e estruturas sanduíche, baseando-se no comportamento vibro-acústico da estrutura. Isto foi feito por duas abordagens distintas: experimental e numérica. Na abordagem experimental, estudou-se a possibilidade de usar parâmetros obtidos com base no som radiado pela estrutura para fazer a identificação de defeitos em uma placa-sandu íche, na qual defeitos foram deliberadamente introduzidos durante a fabricação. Foram testados dois parâmetros psicoacústicos — loudness e sharpness — e o chamado Índice de discrepância. Com estas três métricas foi possível identificar falhas. Contudo, dificuldades como indicações de defeito em locais onde não há nenhum e o tempo de duração do ensaio permanecem como obstáculos a serem vencidos. Na abordagem numérica...

Conception of sandwich structural panels comprising thin walled steel fibre reinforced self-compacting concrete (SFRSCC) and fibre reinforced polymer (FRP) connectors

Lameiras, Rodrigo; Barros, Joaquim A. O.; Azenha, Miguel; Valente, Isabel
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 ENG
Relevância na Pesquisa
36.29%
In this paper, an innovative thermally efficient sandwich structural panel is proposed for the structural walls of a pre-fabricated modular housing system. Traditionally, sandwich concrete panels consist of conventional reinforced concrete wythes as external layers, polystyrene foam as core material and steel connectors. However, steel connectors are known to cause thermal bridges on the building envelope and possibly condensation and mould problems. Furthermore, the possibilities for thickness reduction/optimization of conventionally reinforced concrete layers are frequently limited by minimum cover requirements. To overcome these issues, the proposed sandwich panel comprises Fibre Reinforced Polymer (FRP) connectors and two thin layers of Steel Fibre Reinforced SelfCompacting Concrete (SFRSCC). This paper presents the basic conception of the proposed building system together with preliminary parametric numerical analyses to define the arrangement and geometry of the elements that constitute the sandwich panels. Finally, the feasibility of using the proposed connector and SFRSCC on the external wythes is experimentally investigated through a series of pull-out tests where failure modes and load capacity of the connections are analysed.

Development of sandwich-form biosensor to detect Mycobacterium tuberculosis complex in clinical sputum specimens

Shojaei,Taha Roodbar; Salleh,Mohamad Amran Mohd; Tabatabaei,Meisam; Ekrami,Alireza; Motallebi,Roya; Rahmani-Cherati,Tavoos; Hajalilou,Abdollah; Jorfi,Raheleh
Fonte: Brazilian Society of Infectious Diseases Publicador: Brazilian Society of Infectious Diseases
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 EN
Relevância na Pesquisa
36.21%
Mycobacterium tuberculosis, the causing agent of tuberculosis, comes second only after HIV on the list of infectious agents slaughtering many worldwide. Due to the limitations behind the conventional detection methods, it is therefore critical to develop new sensitive sensing systems capable of quick detection of the infectious agent. In the present study, the surface modified cadmium-telluride quantum dots and gold nanoparticles conjunct with two specific oligonucleotides against early secretory antigenic target 6 were used to develop a sandwich-form fluorescence resonance energy transfer-based biosensor to detect M. tuberculosis complex and differentiate M. tuberculosis and M. bovis Bacille Calmette–Guerin simultaneously. The sensitivity and specificity of the newly developed biosensor were 94.2% and 86.6%, respectively, while the sensitivity and specificity of polymerase chain reaction and nested polymerase chain reaction were considerably lower, 74.2%, 73.3% and 82.8%, 80%, respectively. The detection limits of the sandwich-form fluorescence resonance energy transfer-based biosensor were far lower (10 fg) than those of the polymerase chain reaction and nested polymerase chain reaction (100 fg). Although the cost of the developed nanobiosensor was slightly higher than those of the polymerase chain reaction-based techniques...

Diagnosis of arboviruses using indirect sandwich IgG ELISA in horses from the Brazilian Amazon

Casseb,Alexandre do Rosário; Nunes,Márcio Roberto Teixeira; Rodrigues,Sueli Guerreiro; Rosa,Elizabeth Salbé Travassos da; Casseb,Livia Medeiros Neves; Casseb,Samir Manssor Moraes; Silva,Sandro Patroca da; Rodrigues,Érika Dayane Leal; Vasconcelos,Pedro
Fonte: Centro de Estudos de Venenos e Animais Peçonhentos - CEVAP, Universidade Estadual Paulista - UNESP Publicador: Centro de Estudos de Venenos e Animais Peçonhentos - CEVAP, Universidade Estadual Paulista - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
26.26%
Background The Amazon as a whole is the largest reservoir of arboviruses worldwide, while the Brazilian Amazon hosts the largest variety of arboviruses isolated to date. In this study, the results of an indirect sandwich IgG ELISA, standardized for 19 arbovirustypes circulating among horses in Brazilian Amazon, were compared to results of the hemagglutination inhibition test. A screening test assessed the conditional probability distribution and a Pearson linear correlation test determined the correlation strength among the absorbance values recorded for viruses from the same family. Findings Sensitivity varied between 40.85 and 100%; the specificity was low and ranged from 39.71 to 67.0%; and the accuracy varied between 41 and 65.2%. The test developed in this study yielded a large number of serological cross-reactions. Conclusions The test can be employed to detect IgG antibodies within one arbovirus family; however, the hemagglutination test or other more specific techniques, such as the serum neutralization test in mice or the plaque-reduction neutralization test, are essential complementary methods for positive cases.

Cytomegalovirus in urine: detection of viral DNA by sandwich hybridization.

Virtanen, M; Syvänen, A C; Oram, J; Söderlund, H; Ranki, M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1984 EN
Relevância na Pesquisa
26.43%
A cytomegalovirus (CMV)-specific sandwich hybridization test was constructed by using two adjacent BamHI DNA fragments of CMV DNA as reagents. The fragments were cloned into two different vectors. One of the recombinants was attached to the filter, and the other was the labeled probe. When present in the sample, CMV DNA mediated labeling of the filter by hybridizing to both the filter-bound DNA and the probe. The sandwich hybridization test was applied for the detection of CMV DNA from urine. DNA was released from virus by 2% Sarkosyl, concentrated by 2-butanol extraction and isopropanol precipitation, denatured, and finally subjected to the sandwich hybridization test. As a result, 70 to 90% of the original viral DNA could be recovered and demonstrated by the quantitative hybridization reaction. Urine could be stored at room temperature in Sarkosyl for at least 2 days without affecting the detectability of CMV. The clinical applicability of the test was evaluated by studying urine samples from four infants excreting CMV. Sandwich hybridization demonstrated the presence of CMV DNA in all of the specimens. These contained originally 10(5) to 10(8) CMV DNA molecules per ml.

Prospective Comparison of the Diagnostic Potential of Real-Time PCR, Double-Sandwich Enzyme-Linked Immunosorbent Assay for Galactomannan, and a (1→3)-β-d-Glucan Test in Weekly Screening for Invasive Aspergillosis in Patients with Hematological Disorders

Kawazu, Masahito; Kanda, Yoshinobu; Nannya, Yasuhito; Aoki, Katsunori; Kurokawa, Mineo; Chiba, Shigeru; Motokura, Toru; Hirai, Hisamaru; Ogawa, Seishi
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /06/2004 EN
Relevância na Pesquisa
26.23%
The establishment of an optimal noninvasive method for diagnosing invasive aspergillosis (IA) is needed to improve the management of this life-threatening infection in patients with hematological disorders, and a number of noninvasive tests for IA that target different fungal components, including galactomannan, (1→3)-β-d-glucan (BDG), and Aspergillus DNA, have been developed. In this study, we prospectively evaluated the diagnostic potential of three noninvasive tests for IA that were used in a weekly screening strategy: the double-sandwich enzyme-linked immunosorbent assay (ELISA) for galactomannan (Platelia Aspergillus), a real-time PCR assay for Aspergillus DNA (GeniQ-Asper), and an assay for BDG (β-glucan Wako). We analyzed 149 consecutive treatment episodes in 96 patients with hematological disorders who were at high risk for IA and diagnosed 9 proven IA cases, 2 probable IA cases, and 13 possible invasive fugal infections. In a receiver-operating characteristic (ROC) analysis, the area under the ROC curve was greatest for ELISA, using two consecutive positive results (0.97; P = 0.036 for ELISA versus PCR, P = 0.055 for ELISA versus BDG). Based on the ROC curve, the cutoff for the ELISA could be reduced to an optical density index (O.D.I.) of 0.6. With the use of this cutoff for ELISA and cutoffs for PCR and BDG that give a comparable level of specificity...

Comparison of a latex agglutination test with other serological tests for the measurement of antibodies to Toxoplasma gondii.

Payne, R A; Francis, J M; Kwantes, W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1984 EN
Relevância na Pesquisa
26.3%
One hundred sera from 49 patients with glandular toxoplasmosis were examined by a latex agglutination test, the dye test, an indirect haemagglutination test, and a double antibody sandwich enzyme linked immunosorbent assay (ELISA) for antitoxoplasma IgM. The results support previous findings that the dye test, indirect haemagglutination test, and latex agglutination test measure different antibodies to Toxoplasma gondii. In early glandular toxoplasmosis, when specific IgM was detected, the titres of both the latex agglutination test and the indirect haemagglutination test were lower than the dye test. Repeat specimens from 11 of the patients showed four cases in which the latex agglutination test titres never exceeded 1/256, whereas both the dye test and the indirect haemagglutination test showed significant titres and specific IgM was detected in every case. We conclude that the latex agglutination test should not be used as a substitute for the dye test in the serological diagnosis of glandular toxoplasmosis. All sera giving a positive latex agglutination test result should be referred for further tests. A combination of the dye test and double antibody sandwich ELISA gives the most reliable serological diagnosis of early glandular toxoplasmosis.

Preparation and Evaluation of Recombinant Severe Fever with Thrombocytopenia Syndrome Virus Nucleocapsid Protein for Detection of Total Antibodies in Human and Animal Sera by Double-Antigen Sandwich Enzyme-Linked Immunosorbent Assay

Jiao, Yongjun; Zeng, Xiaoyan; Guo, Xiling; Qi, Xian; Zhang, Xiao; Shi, Zhiyang; Zhou, Minghao; Bao, Changjun; Zhang, Wenshuai; Xu, Yan; Wang, Hua
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /02/2012 EN
Relevância na Pesquisa
26.3%
The recent emergence of the human infection confirmed to be caused by severe fever with thrombocytopenia syndrome virus (SFTSV) in China is of global concern. Safe diagnostic immunoreagents for determination of human and animal seroprevalence in epidemiological investigations are urgently needed. This paper describes the cloning and expression of the nucleocapsid (N) protein of SFTSV. An N-protein-based double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) system was set up to detect the total antibodies in human and animal sera. We reasoned that as the double-antigen sandwich ELISA detected total antibodies with a higher sensitivity than traditional indirect ELISA, it could be used to detect SFTSV-specific antibodies from different animal species. The serum neutralization test was used to validate the performance of this ELISA system. All human and animal sera that tested positive in the neutralization test were also positive in the sandwich ELISA, and there was a high correlation between serum neutralizing titers and ELISA readings. Cross-reactivity was evaluated, and the system was found to be highly specific to SFTSV; all hantavirus- and dengue virus-confirmed patient samples were negative. SFTSV-confirmed human and animal sera from both Anhui and Hubei Provinces in China reacted with N protein in this ELISA...

Development and Application of a Double-Antigen Sandwich Enzyme-Linked Immunosorbent Assay for Detection of Antibodies to Porcine Circovirus 2

Ge, Meng; Luo, Wei; Jiang, Daliang; Li, Runcheng; Zhao, Wenwei; Chen, Guoliang; Yang, Xingdong; Yu, Xinglong
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2012 EN
Relevância na Pesquisa
26.45%
A double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) is described for detection of porcine circovirus 2 (PCV2) antibodies using the well-characterized recombinant PCV2 capsid protein. In a comparative test of 394 pig sera against an indirect immunofluorescence (IIF) test and a commercial ELISA kit (also based on the recombinant PCV2 capsid protein), the results showed that the diagnostic sensitivity, specificity, and accuracy of the assay were, respectively, 90.61, 94.02, and 91.62% compared with IIF and 94.38, 95.28, and 94.67% compared with the commercial ELISA kit. Assay of 12 PCV-free pigs over a 5-week period produced only PCV2-negative titers by all 3 methods. These results and the seroprofiles of 4 pig farms obtained by both the commercial ELISA kit and the double-antigen sandwich ELISA indicate that the sandwich ELISA is a reliable method for detection of antibodies to PCV2. Additionally, the method described here permits the use of undiluted test serum samples simultaneously loaded with horseradish peroxidase (HRP)-conjugated antigen into the test well, and the complete test procedure can be performed in less than 90 min. This double-antigen sandwich ELISA should be a useful tool to aid swine industry professionals in deciding the intervention strategies for the control of PCV2-associated diseases.

A simple set of validation steps identifies and removes false results in a sandwich enzyme-linked immunosorbent assay caused by anti-animal IgG antibodies in plasma from arthritis patients

Kragstrup, Tue W; Vorup-Jensen, Thomas; Deleuran, Bent; Hvid, Malene
Fonte: Springer International Publishing AG Publicador: Springer International Publishing AG
Tipo: Artigo de Revista Científica
Publicado em 15/06/2013 EN
Relevância na Pesquisa
26.25%
Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are chronic diseases characterized by activation of the immune system and production of antibodies. Thus, rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies in plasma samples from arthritis patients can interfere with immunoassays such as sandwich enzyme-linked immunosorbent assay (ELISA) systems often used in arthritis research. However, standard methodologies on how to test for false results caused by these antibodies are lacking. The objective of this study was to design a simple set of steps to validate a sandwich ELISA before using it for measuring analytes in plasma from arthritis patients. An interleukin-24 (IL-24) sandwich ELISA system was prepared with a monoclonal mouse capture antibody and a polyclonal goat detection antibody and tested for interference by rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies. Plasma samples from 23 patients with RA and SpA were used. No differences were found between plasma samples measured in wells coated with anti-IL-24 specific antibody and in wells coated with isotype control antibody (false positive results), and recombinant human IL-24 was not recovered in spiked samples (false negative results). This interference was removed after preincubating the plasma samples from patients with arthritis with goat or bovine IgG...

Rapid and quantitative detection of C-reactive protein using quantum dots and immunochromatographic test strips

Cheng, Xianglin; Pu, Xu; Jun, Pen; Zhu, XiaoBo; Zhu, Di; Chen, Ming
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
35.99%
Background: Rapid immunochromatographic tests can detect disease markers in 10–15 minutes, which facilitates clinical diagnosis and treatment programs. However, most immunochromatographic tests employ gold nanoparticles as reporters, and these have only moderate sensitivity and act as qualitative methods for analyzing high biomarker concentrations. Methods: In this study, we introduce quantum dots (QDs) as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT) to analyze C-reactive protein (CRP) levels. Goat anti-rabbit IgG and rabbit IgG were used as control antibodies, and mouse monoclonal CRP antibody pairs were used for disease marker detection. One monoclonal CRP antibody was conjugated with QDs and served as a signal antibody, and the other monoclonal CRP antibody was dispensed onto the nitrocellulose membrane and served as a capturing antibody. In the presence of CRP, the fluorescence intensity of the monoclonal antibody-CRP-monoclonal antibody sandwich complex captured on the nitrocellulose membrane was determined using the fluorescence strip reader. Results: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L...

Fluid structure interaction effect on sandwich composite structures

Violette, Michael A.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
26.35%
The objective of this research is to examine the fluid structure interaction (FSI) effect on composite sandwich structures under a low velocity impact. The primary sandwich composite used in this study was a 6.35-mm balsa core and a multi-ply symmetrical plain weave 6 oz E-glass skin. The specific geometry of the composite was a 305 by 305 mm square with clamped boundary conditions. Using a uniquely designed vertical drop-weight testing machine, there were three fluid conditions in which these experiments focused. The first of these conditions was completely dry (or air) surrounded testing. The second condition was completely water submerged. The final condition was a wet top/air-backed surrounded test. The tests were conducted progressively from a low to high drop height to best conclude the onset and spread of damage to the sandwich composite when impacted with the test machine. The measured output of these tests was force levels and multi-axis strain performance. The collection and analysis of this data will help to increase the understanding of the study of sandwich composites, particularly in a marine environment.

Análisis y modelización de vigas sándwich sometidas a impactos de baja velocidad

Iváñez del Pozo, Inés
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado
SPA
Relevância na Pesquisa
36.39%
En esta Tesis Doctoral se ha estudiado el comportamiento frente a impactos de baja velocidad de vigas sándwich constituidas por pieles de material compuesto de tipo laminado y núcleo de nido de abeja de aluminio. Existen tres clases de metodologías para hacer frente a este estudio: el análisis experimental, los modelos analíticos y las simulaciones numéricas. La realización de un estudio experimental exhaustivo supone una gran inversión, tanto en términos económicos como temporales, por lo que la utilización de modelos analíticos y herramientas de simulación representa una alternativa eficiente. Los modelos analíticos permiten evaluar variables globales como la fuerza o el desplazamiento pero sin llegar a profundizar en el proceso de fallo de pieles y núcleo. Las simulaciones numéricas suelen lograr descripciones más precisas y detalladas de la respuesta a impacto y su flexibilidad en relación a las variaciones de condiciones de contorno, geometría y material, es muy apreciada en el campo de la investigación. Disponer de modelos numéricos permite profundizar en el conocimiento del comportamiento a impacto de las estructuras sándwich, proporcionando información que es difícilmente extraíble de forma experimental. No obstante...

Deformation and Fracture of Impulsively Loaded Sandwich Panels

Wadley, Haydn N. G.; Børvik, Tore; Olovsson, Lars; Wetzel, John J.; Dharmasena, Kumar P.; Hopperstad, Odd Sture; Deshpande, Vikram; Hutchinson, John W.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.38%
Light metal sandwich panel structures with cellular cores have attracted interest for multifunctional applications which exploit their high bend strength and impact energy absorption. This concept has been explored here using a model 6061-T6 aluminum alloy system fabricated by friction stir weld joining extruded sandwich panels with a triangular corrugated core. Micro-hardness and miniature tensile coupon testing revealed that friction stir welding reduced the strength and ductility in the welds and a narrow heat affected zone on either side of the weld by approximately 30%. Square, edge clamped sandwich panels and solid plates of equal mass per unit area were subjected to localized impulsive loading by the impact of explosively accelerated, water saturated, sand shells. The hydrodynamic load and impulse applied by the sand were gradually increased by reducing the stand-off distance between the test charge and panel surfaces. The sandwich panels suffered global bending and stretching, and localized core crushing. As the pressure applied by the sand increased, face sheet fracture by a combination of tensile stretching and shear-off occurred first at the two clamped edges of the panels that were parallel with the corrugation and weld direction. The plane of these fractures always lay within the heat affected zone of the longitudinal welds. For the most intensively loaded panels additional cracks occurred at the other clamped boundaries and in the center of the panel. To investigate the dynamic deformation and fracture processes...

ompA gene in the detection of Escherichia coli and other Enterobacteriaceae by nucleic acid sandwich hybridization.

Palva, A M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1983 EN
Relevância na Pesquisa
26.28%
The applicability of the DNA sandwich hybridization method to detection of bacterial DNA from crude samples is demonstrated using Escherichia coli as a model. In sandwich hybridization the sample DNA mediates the binding of a labeled probe DNA fragment to a second DNA bound on filter. For this study the DNA reagents were prepared by subclonings from a recombinant plasmid containing the E. coli K-12 ompA gene and an adjacent fragment of E. coli DNA. The 5' half of the ompA gene (738 base pairs) in pBR322 served as the filter reagent. The 3' half of the ompA gene (300 base pairs) and the adjacent 1,500 base pairs of E. coli DNA were cloned into the single-stranded phage vector M13mp7, and the resulting recombinant phage DNA was labeled with 125I and used as probe in the hybridizations. For maximal hybridization the DNA reagents had to be present in excess of the sample nucleic acid, which was preferably fragmented before testing. In the optimized test, 3 X 10(6) molecules of E. coli DNA from lysed cells were detected by an overnight reaction; the sensitivity of the test was not affected by the presence of 10(9) unrelated bacteria. With the ompA reagents, all members of the family Enterobacteriaceae tested were detected even if the sensitivity was decreased as compared with that for the homologous bacteria. With all other bacteria...

Design of Sandwich Structures

Petras, Achilles
Fonte: University of Cambridge; Department of Engineering Publicador: University of Cambridge; Department of Engineering
Tipo: Thesis; doctoral; PhD
EN
Relevância na Pesquisa
36.48%
Failure modes for sandwich beams of GFRP laminate skins and Nomex honeycomb core are investigated. Theoretical models using honeycomb mechanics and classical beam theory are described. A failure mode map for loading under 3-point bending, is constructed, showing the dependence of failure mode and load on the ratio of skin thickness to span length and honeycomb relative density. Beam specimens are tested in 3-point bending. The effect of honeycomb direction is also examined. The experimental data agree satisfactorily with the theoretical predictions. The results reveal the important role of core shear in a sandwich beam's bending behaviour and the need for a better understanding of indentation failure mechanism. High order sandwich beam theory (HOSBT) is implemented to extract useful information about the way that sandwich beams respond to localised loads under 3-point bending. 'High-order' or localised effects relate to the non-linear patterns of the in-plane and vertical displacements fields of the core through its height resulting from the unequal deformations in the loaded and unloaded skins. The localised effects are examined experimentally by Surface Displacement Analysis of video images recorded during 3-point bending tests. A new parameter based on the intrinsic material and geometric properties of a sandwich beam is introduced to characterise its susceptibility to localised effects. Skin flexural rigidity is shown to play a key role in determining the way that the top skin allows the external load to pass over the core. Furthermore...

Blast protection of infrastructure using advanced composites

Brodsky, Evan
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
26.25%
Gillespie, Jr., John W.; This research was a systematic investigation detailing the energy absorption mechanisms of an E-glass web core composite sandwich panel subjected to an impulse loading applied orthogonal to the facesheet. Key roles of the fiberglass and polyisocyanurate foam material were identified, characterized, and analyzed. A quasi-static test fixture was used to compressively load a unit cell web core specimen machined from the sandwich panel. The web and foam both exhibited non-linear stress-strain responses during axial compressive loading. Through several analyses, the composite web situated in the web core had failed in axial compression. Optimization studies were performed on the sandwich panel unit cell in order to maximize the energy absorption capabilities of the web core. Ultimately, a sandwich panel was designed to optimize the energy dissipation subjected to through-the-thickness compressive loading.; University of Delaware, Department of Civil and Environmental Engineering; M.C.E.

Sandwich test para avaliação de grouts

Freitas, Nuno Rodolfo Gomes
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
56.35%
A presente dissertação visa estudar métodos de ensaio para avaliar as características de grouts não estruturais a utilizar na consolidação de revestimentos de edifícios com destacamento de uma/várias camadas. Neste sentido, foi realizado o ensaio sandwich para simulação de destacamento de camadas. É introduzida uma nova variante deste ensaio seguindo as normas europeias e realizados os ensaios de referência. Apresenta-se a metodologia adotada e faz-se a exposição, comparação, análise e justificação dos ensaios e retiram-se as conclusões bem como os desenvolvimentos futuros.; This thesis aims to study test methods for evaluating the characteristics of non-structural grouts to be used for consolidation of buildings coatings with detachment of one or several layers. Thus, we performed the sandwich trial for layers detachment simulation. A new variant of this essay following the European standards is introduced and reference trials are done. The methodology adopted, exposure, comparison, analysis, trials justification, conclusions taken and future developments are shown.; Mestrado em Engenharia Civil