Contribuição ao estudo da retificação abrasiva de materiais cerâmicos

Uma das principais limitações relacionadas ao processo de retificação de cerâmica é a confiabilidade do material devido aos defeitos introduzidos no processamento. A compreensão dos mecanismos envolvidos na remoção de material durante a retificação e a interação com os parâmetros de processo e microestrutura é fundamental para minimizar estes defeitos. A proposta desta revisão é apresentar os modelos de remoção de material e a forma como afetam as propriedades mecânicas da peça final.

Efeitos dos esteroides anabólicos androgênicos sobre funções cognitivas de ratos

The use and the demand for substances that enhance masculinity, strength and sexual power are not novel. Over the years, this search has assisted the research directions in this area, leading to the discovery of the primary male sex hormone testosterone in 1935. Since then, numerous testosterone analogue compounds were synthesized, which are generically called Anabolic Androgenic Steroids (AAS). The AAS were produced for therapeutic purposes, but an increase in the use of these compounds for other purposes occurred over time. Initially they were used mainly to improve performance in athletes. However, recent studies have shown that the use of AAS by non-athletes with aesthetical purposes have been increasing as well. The abuse of AAS with non-clinical purposes can promote a number of physiological alterations, such as heart, liver, respiratory and psychological problems such as changes in mood, levels of anxiety and aggression. Exposure to supraphysiological doses of AAS is associated with behavioral changes, however, little is known about the effects of AAS on cognitive functions. In this work, we aimed to mimic the AAS abuse in humans with intramuscular administration of a supraphysiological dose of testosterone propionate (TP) in rats. We investigated the effects of this treatment on different aspects of cognitive function, specifically learning, memory and anxiety. Adult male Wistar rats were tested in the spontaneous alternation, novel object recognition and plus-maze discriminative avoidance tasks. The control group received intramuscular injections of vegetable oil (vehicle), and the TP group received injections of TP (10 mg/kg, i.m.). The injections were administered for 40 days, with intervals of 48 hours (chronic treatment) or in a single injection (acute treatment). In addition to the behavioral assessments, we performed biochemical analyzes as indicators of the endocrine effects of the treatment. Our results show that chronic treatment with a supraphysiological dose of TP caused memory impairments in the novel object recognition and the discriminative avoidance tasks. The spatial working memory (evaluated by spontaneous alternation task) was not affected. Also, we did not observe changes in anxiety levels. Regarding the biochemical parameters, chronic treatment increased serum levels of glutamicpyruvic transaminase, an indicator of hepatic and pancreatic lesions (as those observed after chronic use of these substances in humans). On the other hand, acute treatment with PT did not promote significant changes in any of these parameters when compared to the control group. In summary, we conclude that chronic treatment with a supraphysiological dose of testosterone propionate produces memory deficits in novel object recognition and retrieval of the discriminative avoidance task in adult male rats

Estudo da regeneração de aditivos para catalisadores de craqueamento aluminofosfatos (ALPO s)e silicoaluminofosfatos (SAPO s)

Heterogeneous catalysts such as aluminophosphate and silicoaluminophosphate, molecular sieves with AEL of ALPO-11 and SAPO-11, were synthesized by the hydrothermal method with the following molar composition: 2.9 Al +3.2 P + 3.5 DIPA +32.5 H20 (ALPO-11); 2.9 Al +3.2 P + 0.5 Si + 3.5 DIPA +32.5 H20 (SAPO-11) starting from silica (only in the SAPO-11), pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. The crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 170ºC for a period of 48 hours under autogeneous pressure. The obtained materials were washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), thermo gravimetric differential thermal analysis (TG/DTA) and nitrogen adsorption (BET). The acidic properties were determined using adsorption of n-butylamine followed by programmed thermodessorption. This method revealed that ALPO-11 has weaker acid sites due to structural defects, while SAPO-11 shows an acidity that ranges from weak to moderate. However, a small quantity of strong acid sites could be detected there. The deactivation of the catalysts was conducted by the cracking of the n-hexane in a fixed bed continuous flow microrreator coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the regeneration and removal of the organic template

Craqueamento térmico e termocatalítico do óleo de girassol (Hellianthus annus L.) sobre materiais micro e mesoporosos

Microporous materials zeolite type Beta and mesoporous type MCM-41 and AlMCM-41 were synthesized hydrothermally and characterized by methods of X-ray diffraction, Fourier transform infrared, scanning electron microscopy, surface acidity, nitrogen adsorption, thermal analysis TG / DTG. Also we performed a kinetic study of sunflower oil on micro and mesoporous catalysts. The microporous material zeolite beta showed a lower crystallinity due to the existence of smaller crystals and a larger number of structural defects. As for the mesoporous materials MCM-41 and AlMCM-41 samples showed formation of hexagonal one-dimensional structure. The study of kinetic behavior of sunflower oil with zeolite beta catalysts, AlMCM-41 and MCM-41 showed a lower activation energy in front of the energy of pure sunflower oil, mainly zeolite beta. In the thermal cracking and thermocatalytic of sunflower oil were obtained two liquid fractions containing an aqueous phase and another organic - organic liquid fraction (FLO). The FLO first collected in both the thermal cracking as the thermocatalytic, showed very high level of acidity, performed characterizations of physicochemical properties of the second fraction in accordance with the specifications of the ANP. The second FLO thermocatalytic collected in cracking of sunflower oil presented results in the range of diesel oil, introducing himself as a promising alternative for use as biofuel liquid similar to diesel, either instead or mixed with it

Estudo da descelularização tecidual na produção de arcabouços biológicos para enxertos

The regeneration of bone defects with loss of substance remains as a therapeutic challenge in the medical field. There are basically four types of grafts: autologous, allogenic, xenogenic and isogenic. It is a consensus that autologous bone is the most suitable material for this purpose, but there are limitations to its use, especially the insufficient amount in the donor. Surveys show that the components of the extracellular matrix (ECM) are generally conserved between different species and are well tolerated even in xenogenic recipient. Thus, several studies have been conducted in the search for a replacement for autogenous bone scaffold using the technique of decellularization. To obtain these scaffolds, tissue must undergo a process of cell removal that causes minimal adverse effects on the composition, biological activity and mechanical integrity of the remaining extracellular matrix. There is not, however, a conformity among researchers about the best protocol for decellularization, since each of these treatments interfere differently in biochemical composition, ultrastructure and mechanical properties of the extracellular matrix, affecting the type of immune response to the material. Further down the arsenal of research involving decellularization bone tissue represents another obstacle to the arrival of a consensus protocol. The present study aimed to evaluate the influence of decellularization methods in the production of biological scaffolds from skeletal organs of mice, for their use for grafting. This was a laboratory study, sequenced in two distinct stages. In the first phase 12 mice hemi-calvariae were evaluated, divided into three groups (n = 4) and submitted to three different decellularization protocols (SDS [group I], trypsin [Group II], Triton X-100 [Group III]). We tried to identify the one that promotes most efficient cell removal, simultaneously to the best structural preservation of the bone extracellular matrix. Therefore, we performed quantitative analysis of the number of remaining cells and descriptive analysis of the scaffolds, made possible by microscopy. In the second stage, a study was conducted to evaluate the in vitro adhesion of mice bone marrow mesenchymal cells, cultured on these scaffolds, previously decellularized. Through manual counting of cells on scaffolds there was a complete cell removal in Group II, Group I showed a practically complete cell removal, and Group III displayed cell remains. The findings allowed us to observe a significant difference only between Groups II and III (p = 0.042). Better maintenance of the collagen structure was obtained with Triton X-100, whereas the decellularization with Trypsin was responsible for the major structural changes in the scaffolds. After culture, the adhesion of mesenchymal cells was only observed in specimens deccelularized with Trypsin. Due to the potential for total removal of cells and the ability to allow adherence of these, the protocol based on the use of Trypsin (Group II) was considered the most suitable for use in future experiments involving bone grafting decellularized scaffolds

Qualidade do serviço prestado aos pacientes de cirurgia cardíaca do Sistema Único de Saúde - SUS

OBJETIVO: Avaliar qualidade do serviço prestado aos pacientes de cirurgia cardíaca no período hospitalar, em serviço do SUS, identificando as expectativas e percepções dos pacientes. Relacionar qualidade de serviço com gênero, faixa etária e circulação extracorpórea. MÉTODOS: Estudaram-se 82 pacientes (52,4% do sexo feminino e 47,6% do masculino) submetidos a cirurgia cardíaca eletiva, operados por toracotomia médio-esternal, idade: 31 a 83 anos (média 60,4 ± 13,2 anos), período: março a setembro de 2006. Avaliou-se a qualidade do serviço em dois momentos: expectativas no pré-operatório e percepções do atendimento recebido no 6º dia de pós-operatório; mediante aplicação da escala SERVQUAL modificada (SERVQUAL-Card). O resultado foi obtido pela diferença da somatória das notas das percepções e expectativas por meio de análise estatística. RESULTADOS: A escala SERVQUAL-Card foi validada estatisticamente, apresentando adequado índice de consistência interna. Encontrou-se maior frequência de revascularização do miocárdio 55 (67,0%); primeira cirurgia cardíaca 72 (87,8%) e utilização de CEC 69 (84,1%). Verificaram-se altos valores para expectativas e percepções, com resultados significantes (P<0,05). Observou-se relação significante entre qualidade de serviço com gênero, na empatia (P=0,04) e faixa etária, na confiabilidade (P=0,02). Não se observou significância entre CEC e qualidade de serviço. CONCLUSÃO: A qualidade dos serviços foi satisfatória. O paciente demonstrou expectativa alta ao serviço médicohospitalar. Mulheres apresentaram maior percepção da qualidade na empatia, jovens na confiabilidade. A utilização de CEC não está relacionada com qualidade do serviço nesta amostra. Os dados obtidos sugerem que a qualidade deste serviço de saúde pode ser monitorada pelo emprego periódico da escala SERQUAL.

Beta-bloqueadores em anestesiologia: aspectos farmacológicos e clínicos

JUSTIFICATIVA E OBJETIVOS: Informações experimentais e clínicas têm sugerido que os b-bloqueadores apresentam efeitos hemodinâmicos importantes e protetores durante o ato anestésico-cirúrgico. O objetivo deste trabalho é revisar as informações farmacológicas e clínicas dos b-bloqueadores para sua utilização adequada na medicina per-operatória. CONTEÚDO: Os b-bloqueadores seletivos inibem preferencialmente os b1-receptores reduzindo a freqüência e inotropismo cardíacos e determinando redução no consumo de oxigênio do miocárdio. Os b-bloqueadores não seletivos inibem também os b2-receptores, aumentando a resistência bronquiolar e vascular periférica. Alguns b-bloqueadores são, também, vasodilatadores. O tratamento prolongado com os b-bloqueadores aumenta a densidade dos b-receptores na membrana celular, o que pode explicar a hiperatividade simpática que pode ocorrer durante a parada do tratamento desses medicamentos. em cirurgia não cardíaca, os efeitos benéficos do b-bloqueadores em pacientes hipertensos ou nos que apresentam doença coronariana têm sido demonstrados, com redução da incidência de isquemia miocárdica no pós-operatório e da mortalidade durante o período de dois anos que se segue à operação. CONCLUSÕES: O tratamento com b-bloqueadores deve ser mantido até o período da manhã da operação, exceto nos pacientes com sinais de intolerância à droga, como hipotensão ou bradicardia importante. Os b-bloqueadores exercem efeito benéfico na recuperação pós-operatória de pacientes com doenças cardiovasculares ou nos que apresentam fatores de risco. Por isso, o emprego desses medicamentos é importante na medicina per-operatória e deve ser ampliado.

Uma abordagem sistemática para implementação, gerenciamento e customização de testes de linhas de produto de software

Through the adoption of the software product line (SPL) approach, several benefits are achieved when compared to the conventional development processes that are based on creating a single software system at a time. The process of developing a SPL differs from traditional software construction, since it has two essential phases: the domain engineering - when common and variables elements of the SPL are defined and implemented; and the application engineering - when one or more applications (specific products) are derived from the reuse of artifacts created in the domain engineering. The test activity is also fundamental and aims to detect defects in the artifacts produced in SPL development. However, the characteristics of an SPL bring new challenges to this activity that must be considered. Several approaches have been recently proposed for the testing process of product lines, but they have been shown limited and have only provided general guidelines. In addition, there is also a lack of tools to support the variability management and customization of automated case tests for SPLs. In this context, this dissertation has the goal of proposing a systematic approach to software product line testing. The approach offers: (i) automated SPL test strategies to be applied in the domain and application engineering, (ii) explicit guidelines to support the implementation and reuse of automated test cases at the unit, integration and system levels in domain and application engineering; and (iii) tooling support for automating the variability management and customization of test cases. The approach is evaluated through its application in a software product line for web systems. The results of this work have shown that the proposed approach can help the developers to deal with the challenges imposed by the characteristics of SPLs during the testing process

Beta: uma ferramenta para geração de testes de unidade a partir de especificações B

Formal methods and software testing are tools to obtain and control software quality. When used together, they provide mechanisms for software specification, verification and error detection. Even though formal methods allow software to be mathematically verified, they are not enough to assure that a system is free of faults, thus, software testing techniques are necessary to complement the process of verification and validation of a system. Model Based Testing techniques allow tests to be generated from other software artifacts such as specifications and abstract models. Using formal specifications as basis for test creation, we can generate better quality tests, because these specifications are usually precise and free of ambiguity. Fernanda Souza (2009) proposed a method to define test cases from B Method specifications. This method used information from the machine s invariant and the operation s precondition to define positive and negative test cases for an operation, using equivalent class partitioning and boundary value analysis based techniques. However, the method proposed in 2009 was not automated and had conceptual deficiencies like, for instance, it did not fit in a well defined coverage criteria classification. We started our work with a case study that applied the method in an example of B specification from the industry. Based in this case study we ve obtained subsidies to improve it. In our work we evolved the proposed method, rewriting it and adding characteristics to make it compatible with a test classification used by the community. We also improved the method to support specifications structured in different components, to use information from the operation s behavior on the test case generation process and to use new coverage criterias. Besides, we have implemented a tool to automate the method and we have submitted it to more complex case studies

Efeitos hemodinâmicos e renais da injeção de doses elevadas de clonidina no espaço peridural do cão

JUSTIFICATIVA E OBJETIVOS: Não existem estudos que relatem as repercussões renais determinadas pela injeção de doses elevadas de clonidina no espaço peridural. O objetivo do estudo foi avaliar os efeitos hemodinâmicos e renais determinados pela injeção de doses elevadas de clonidina no espaço peridural do cão. MÉTODO: Vinte animais anestesiados com tiopental sódico e fentanil foram distribuídos aleatoriamente e de forma duplamente encoberta em dois grupos: Grupo 1 ou placebo (n = 10), que recebeu 0,2 mL.kg-1 de solução fisiológica, e Grupo 2 ou clonidina (n = 10), que recebeu 0,2 mL.kg-1 de uma solução contendo 50 µg.mL-1 de clonidina, no espaço peridural. Foram avaliados os seguintes parâmetros hemodinâmicos: freqüência cardíaca (FC): bat.min-1; pressão arterial média (PAM): mmHg; pressão da artéria pulmonar ocluida (PAOP): mmHg; débito cardíaco (DC): L.min-1; volume sistólico (VS): mL; também, os seguintes parâmetros da função renal foram avaliados: fluxo sangüíneo renal (FSR): mL.min-1; resistência vascular renal (RVR): mmHg.mL-1.min; volume urinário minuto (VUM): mL.min-1; depuração de creatinina (D Cr): mL.min-1; depuração de para-aminohipurato (D PAH): mL.min-1; fração de filtração (FF); depuração de sódio (D Na): mL.min-1; depuração de potássio (D K): mL.min-1; excreção fracionária de sódio (EF Na): %; excreção urinária de sódio (U NaV): µEq.min-1; excreção urinária de potássio (U K V): µEq.min-1. O experimento consistiu em três momentos de 20 minutos cada. Os dados foram coletados aos 10 minutos de cada momento e a diurese, no início e no final de cada momento. Ao término de M1, a clonidina ou a solução fisiológica foi administrada no espaço peridural. Após período de 20 minutos iniciou-se M2 e, em seguida, M3. RESULTADOS: A clonidina na dose de 10 µg.kg-1 no espaço peridural do cão promoveu alterações significativas, com diminuições da freqüência cardíaca e do débito cardíaco e aumento da relação depuração de para-aminohipurato de sódio/débito cardíaco. CONCLUSÕES: Nas condições realizadas e nas doses empregadas, pode-se concluir que a clonidina não promoveu alteração da função renal, mas diminuiu valores hemodinâmicos (freqüência e débito cardíaco).

Apoiando a construção de testes de aceitação automatizados a partir da especificação de requisitos

Automation has become increasingly necessary during the software test process due to the high cost and time associated with such activity. Some tools have been proposed to automate the execution of Acceptance Tests in Web applications. However, many of them have important limitations such as the strong dependence on the structure of the HTML pages and the need of manual valuing of the test cases. In this work, we present a language for specifying acceptance test scenarios for Web applications called IFL4TCG and a tool that allows the generation of test cases from these scenarios. The proposed language supports the criterion of Equivalence Classes Partition and the tool allows the generation of test cases that meet different combination strategies (i.e., Each-Choice, Base-Choice and All Combinations). In order to evaluate the effectiveness of the proposed solution, we used the language and the associated tool for designing and executing Acceptance Tests on a module of Sistema Unificado de Administração Pública (SUAP) of Instituto Federal Rio Grande do Norte (IFRN). Four Systems Analysts and one Computer Technician, which work as developers of the that system, participated in the evaluation. Preliminary results showed that IFL4TCG can actually help to detect defects in Web applications

Comparação entre pericárdio bovino preservado em glicerina e malha de poliéster no reparo de falhas da parede abdominal em ratos

OBJETIVO: Comparar uma malha comercial de poliéster com o pericárdio bovino preservado em glicerina na reconstituição de defeitos da parede abdominal. MÉTODOS: Foram utilizados 30 ratos, divididos em dois grupos eqüitativos. Efetuou-se uma excisão retangular de 2,5 x 2 cm, incluindo toda a musculatura abdominal e peritônio. No grupo I a parede abdominal foi reparada com malha de poliéster e no grupo II com pericárdio bovino conservado em glicerina. Os animais foram sacrificados aos 15, 60 e 90 dias de pós-operatório, sendo o local cirúrgico avaliado macroscópica e histologicamente. RESULTADOS: Os animais do grupo I apresentaram aderências mais severas e em maior número quando comparados aos do grupo II; porém, sem comprometimento funcional. A análise histológica revelou incorporação dos tecidos aos implantes, com maior resposta fibroblástica nos animais do grupo I. CONCLUSÃO: A malha de poliéster oferece maior resistência estrutural e resposta fibroblástica mais intensa; contudo, promove grande quantidade de aderências às vísceras abdominais, quando comparada ao pericárdio bovino.

Uma abordagem para a verificação do comportamento excepcional a partir de regras de designe e testes

Checking the conformity between implementation and design rules in a system is an important activity to try to ensure that no degradation occurs between architectural patterns defined for the system and what is actually implemented in the source code. Especially in the case of systems which require a high level of reliability is important to define specific design rules for exceptional behavior. Such rules describe how exceptions should flow through the system by defining what elements are responsible for catching exceptions thrown by other system elements. However, current approaches to automatically check design rules do not provide suitable mechanisms to define and verify design rules related to the exception handling policy of applications. This paper proposes a practical approach to preserve the exceptional behavior of an application or family of applications, based on the definition and runtime automatic checking of design rules for exception handling of systems developed in Java or AspectJ. To support this approach was developed, in the context of this work, a tool called VITTAE (Verification and Information Tool to Analyze Exceptions) that extends the JUnit framework and allows automating test activities to exceptional design rules. We conducted a case study with the primary objective of evaluating the effectiveness of the proposed approach on a software product line. Besides this, an experiment was conducted that aimed to realize a comparative analysis between the proposed approach and an approach based on a tool called JUnitE, which also proposes to test the exception handling code using JUnit tests. The results showed how the exception handling design rules evolve along different versions of a system and that VITTAE can aid in the detection of defects in exception handling code

Avaliação da contribuição de desenvolvedores para projetos de software usando mineração de repositórios de software e mineração de processos

Software Repository Mining (MSR) is a research area that analyses software repositories in order to derive relevant information for the research and practice of software engineering. The main goal of repository mining is to extract static information from repositories (e.g. code repository or change requisition system) into valuable information providing a way to support the decision making of software projects. On the other hand, another research area called Process Mining (PM) aims to find the characteristics of the underlying process of business organizations, supporting the process improvement and documentation. Recent works have been doing several analyses through MSR and PM techniques: (i) to investigate the evolution of software projects; (ii) to understand the real underlying process of a project; and (iii) create defect prediction models. However, few research works have been focusing on analyzing the contributions of software developers by means of MSR and PM techniques. In this context, this dissertation proposes the development of two empirical studies of assessment of the contribution of software developers to an open-source and a commercial project using those techniques. The contributions of developers are assessed through three different perspectives: (i) buggy commits; (ii) the size of commits; and (iii) the most important bugs. For the opensource project 12.827 commits and 8.410 bugs have been analyzed while 4.663 commits and 1.898 bugs have been analyzed for the commercial project. Our results indicate that, for the open source project, the developers classified as core developers have contributed with more buggy commits (although they have contributed with the majority of commits), more code to the project (commit size) and more important bugs solved while the results could not indicate differences with statistical significance between developer groups for the commercial project

Obtenção minimamente invasiva de veia safena para cirurgia de revascularização do miocárdio

OBJETIVO: Analisar, comparativamente, a obtenção minimamente invasiva com o uso do MINI-HARVEST® e com instrumental tradicional adaptado. MÉTODO: de junho de 1996 a janeiro de 1999, 63 pacientes submetidos à cirurgia de revascularização do miocárdio tiveram suas veias safenas retiradas segundo técnica minimamente invasiva. Nos 30 primeiros pacientes da série utilizou-se método de visão direta com auxílio de dois afastadores de Langenbeck, e nos 33 restantes utilizou-se o MINI-HARVEST®. RESULTADOS: A idade média dos pacientes era de 61 ± 8,75 anos, sendo 52 homens e 11 mulheres. Quarenta e cinco pacientes eram diabéticos, 45 apresentavam sobrepeso/obesidade, 25 eram tabagistas ativos, 32 apresentavam história pregressa de infarto do miocárdio. O tempo médio de retirada da veia safena com afastadores Langenbeck foi de 34,2 ± 8,14 minutos e com o MINI-HARVEST® de 39,20 ± 9,12 minutos. A extensão de veia retirada foi similar nos dois grupos, variando de 10 a 30 cm. Houve uma deiscência superficial no grupo com afastadores de Langenbeck. Houve necessidade de reversão para método tradicional de retirada em dois casos do grupo MINI-HARVEST® e um do grupo Langenbeck. A incidência de infarto transoperatório foi 4,5% (três) no grupo Langenbeck e 3,1%(dois) no grupo MINI-HARVEST®. CONCLUSÕES: Podemos concluir que o método de obtenção de veia safena minimamente invasivo sob visão direta é efetivo e seguro, tanto com o uso de instrumentos tradicionais adaptados para este fim, como com afastadores especialmente constituídos, ressaltando-se que o MINI-HARVEST® dispensa a presença de um auxiliar.