Bi anisotropia em antenas de microfita retangular e estruturas circulares modificadas

The microstrip antennas in your simplest form consist of a ground plane and a dielectric substrate which supports a conductive tape. As these antennas have some limitations, this work presents a study of anisotropic substrates, as well as some results in microstrip antennas with circular patch, aiming to overcome these limitations, especially in applications at 4G technology. These anisotropic substrates are those in which electrical permittivity and magnetic permeability are represented by tensors of second order. The study consists of a theoretical analysis of substrates and development of a mathematical formalism, the Transverse Transmission Line Method, aimed the application of these substrates in microstrip antennas. Among the substrates used in this study, there are the ferrimagnetic and metamaterials, in which some miniaturizations of the antennas are achieved. For antennas with circular patch, are considered arrays and modified ground planes in order to achieve improvement in parameters, in particular, gain and bandwidth. Several simulations have been made and antennas were constructed so that the measured values could be compared with the simulated values.

Esquina edif��cio: uma proposta arquitet��nica para um edif��cio misto

Natal, como outras cidades metropolitanas brasileiras, sofreu nas ��ltimas d��cadas uma forte transforma����o impulsionada pelo mercado imobili��rio e pela ind��stria da constru����o civil. A produ����o de apartamentos em condom��nios fechados vem crescendo e tornando cada vez mais comum, no cen��rio urbano, a presen��a de torres residenciais (com extensos muros e grades, fachadas cegas e guaritas) que favorecem o ���desurbanismo���. Por outro lado, este tipo de empreendimento, o edif��cio multifamiliar, apresenta plantas baixas padronizadas as quais frequentemente s��o incoerentes com a diversidade de perfis dos usu��rios. A consequ��ncia disso s��o reformas e adequa����es nos apartamentos ap��s a entrega da obra. Diante deste contexto, elaborei uma proposta arquitet��nica, que �� apresentada nesta disserta����o, como alternativa a essa modalidade de produ����o que est�� se tornando dominante no Brasil e em outros pa��ses. Dois conceitos nortearam esta proposta: a) o conceito de urbanidade cujo objetivo no projeto arquitet��nico �� favorecer a percep����o do outro (por copresen��a e/ou coci��ncia) atrav��s da permeabilidade, acessos e passagens entre o edif��cio e o entorno. A maneira como os cheios (barreiras) se estruturam com os vazios foi trabalhada de modo que definissem propriedades espaciais cuja inten����o �� facilitar o encontro e a diversidade entre moradores e entre estes e os de fora, no entanto sem desconsiderar o problema da viol��ncia urbana e, consequentemente a import��ncia da promo����o de seguran��a para os usu��rios. b) o conceito de flexibilidade a fim de possibilitar ao consumidor final o desmembramento da unidade habitacional em duas e, em especial, a participa����o e ou escolha na concep����o do arranjo interno e da defini����o dos acabamentos do seu apartamento. Tudo isto durante a constru����o do empreendimento e ao longo da sua vida ��til, favorecendo assim o potencial de diversidade (grupos sociais), adaptabilidade a fases distintas da vida e durabilidade do edif��cio.

Avalia����o do desempenho de argamassas �� base de cimento Portland para rejuntamento de placas cer��micas tipo II com adi����o de p�� de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Avalia����o do desempenho de argamassas �� base de cimento Portland para rejuntamento de placas cer��micas tipo II com adi����o de p�� de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Evolu����es nas modelagens de substratos artificiais (metamateriais) com pr��ticas experimentais em antenas de microfita

Esse trabalho tem como objetivo apresentar configura����es de substratos diel��tricos inovadores projetados e fabricados a partir de estruturas metamateriais. Para isso, s��o avaliados diversos fatores que podem influenciar no seu desempenho. A princ��pio, foi feito um levantamento bibliogr��fico a respeito dos temas, que est��o relacionados com as pesquisas sobre: materiais diel��tricos, metamateriais e interferometria ��ptica. S��o estudados, pesquisados e desenvolvidos dois projetos experimentais propostos, que comprovam a efici��ncia de m��todos, para se alcan��ar a permeabilidade magn��tica negativa na forma����o de metamateriais. O primeiro projeto �� a produ����o de uma nova estrutura, com u anel ressoador triangular equilateral (Split Equilateral Triangle Resonator - SETR). O segundo projeto: aplica os princ��pios da interferometria ��ptica, especialmente, com o interfer��metro de Fabry-Perot. T��cnicas para obten����o dos dispositivos que complementam a placa metamaterial como substrato foram pesquisadas na literatura e exemplificadas principalmente por meio de simula����es e medi����es. Foram feitas compara����es, simula����es e medi����es de estruturas convencionais e especiais. As experi��ncias se concentram nas evolu����es e modelagens de substratos metamateriais com aplica����es em antenas de microfita. As melhorias de alguns par��metros de desempenho de antenas tamb��m s��o relatadas. As simula����es das antenas foram feitas nos programas computacionais comerciais. Os resultados medidos foram obtidos com um analisador vetorial de redes da Rhode and Schwarz modelo ZVB 14.

Evolu����es nas modelagens de substratos artificiais (metamateriais) com pr��ticas experimentais em antenas de microfita

Esse trabalho tem como objetivo apresentar configura����es de substratos diel��tricos inovadores projetados e fabricados a partir de estruturas metamateriais. Para isso, s��o avaliados diversos fatores que podem influenciar no seu desempenho. A princ��pio, foi feito um levantamento bibliogr��fico a respeito dos temas, que est��o relacionados com as pesquisas sobre: materiais diel��tricos, metamateriais e interferometria ��ptica. S��o estudados, pesquisados e desenvolvidos dois projetos experimentais propostos, que comprovam a efici��ncia de m��todos, para se alcan��ar a permeabilidade magn��tica negativa na forma����o de metamateriais. O primeiro projeto �� a produ����o de uma nova estrutura, com u anel ressoador triangular equilateral (Split Equilateral Triangle Resonator - SETR). O segundo projeto: aplica os princ��pios da interferometria ��ptica, especialmente, com o interfer��metro de Fabry-Perot. T��cnicas para obten����o dos dispositivos que complementam a placa metamaterial como substrato foram pesquisadas na literatura e exemplificadas principalmente por meio de simula����es e medi����es. Foram feitas compara����es, simula����es e medi����es de estruturas convencionais e especiais. As experi��ncias se concentram nas evolu����es e modelagens de substratos metamateriais com aplica����es em antenas de microfita. As melhorias de alguns par��metros de desempenho de antenas tamb��m s��o relatadas. As simula����es das antenas foram feitas nos programas computacionais comerciais. Os resultados medidos foram obtidos com um analisador vetorial de redes da Rhode and Schwarz modelo ZVB 14.

Estudo da influ��ncia de sistemas microemulsionados na molhabilidade de arenitos e na recupera����o avan��ada de petr��leo

Sandstone-type reservoir rocks are commonly responsible for oil accumulation. The wettability is an important parameter for the physical properties of the container, since it interferes in characteristics such as relative permeability to the aqueous phase, residual oil distribution in the reservoir, operating characteristics with waterflood and recovery of crude oil. This study applied different types of microemulsion systems - MES - in sandstone reservoirs and evaluated their influences on wettability and residual oil recovery. For this purpose, four microemulsion were prepared by changing the nature of ionic surfactants (ionic and nonionic). Microemulsions could then be characterized by surface tension analysis, density, particle diameter and viscosity in the temperature range 30�� C to 70�� C. The studied oil was described as light and the sandstone rock was derived from the Botucatu formation. The study of the influence of microemulsion systems on sandstone wettability was performed by contact angle measurements using as parameters the rock treatment time with the MES and the time after the brine surface contact by checking the angle variation behavior. In the study results, the rock was initially wettable to oil and had its wettability changed to mixed wettability after treatment with MES, obtaining preference for water. Regarding rock-MES contact time, it was observed that the rock wettability changed more when the contact time between the surface and the microemulsion systems was longer. It was also noted only a significant reduction for the first 5 minutes of interaction between the treated surface and brine. The synthesized anionic surfactant, commercial cationic, commercial anionic and commercial nonionic microemulsion systems presented the best results, respectively. With regard to enhanced oil recovery performance, all systems showed a significant percentage of recovered oil, with the anionic systems presenting the best results. A percentage of 80% recovery was reached, confirming the wettability study results, which pointed the influence of this property on the interaction of fluids and reservoir rock, and the ability of microemulsion systems to perform enhanced oil recovery in sandstone reservoirs.

Estudo da influ��ncia de sistemas microemulsionados na molhabilidade de arenitos e na recupera����o avan��ada de petr��leo

Sandstone-type reservoir rocks are commonly responsible for oil accumulation. The wettability is an important parameter for the physical properties of the container, since it interferes in characteristics such as relative permeability to the aqueous phase, residual oil distribution in the reservoir, operating characteristics with waterflood and recovery of crude oil. This study applied different types of microemulsion systems - MES - in sandstone reservoirs and evaluated their influences on wettability and residual oil recovery. For this purpose, four microemulsion were prepared by changing the nature of ionic surfactants (ionic and nonionic). Microemulsions could then be characterized by surface tension analysis, density, particle diameter and viscosity in the temperature range 30�� C to 70�� C. The studied oil was described as light and the sandstone rock was derived from the Botucatu formation. The study of the influence of microemulsion systems on sandstone wettability was performed by contact angle measurements using as parameters the rock treatment time with the MES and the time after the brine surface contact by checking the angle variation behavior. In the study results, the rock was initially wettable to oil and had its wettability changed to mixed wettability after treatment with MES, obtaining preference for water. Regarding rock-MES contact time, it was observed that the rock wettability changed more when the contact time between the surface and the microemulsion systems was longer. It was also noted only a significant reduction for the first 5 minutes of interaction between the treated surface and brine. The synthesized anionic surfactant, commercial cationic, commercial anionic and commercial nonionic microemulsion systems presented the best results, respectively. With regard to enhanced oil recovery performance, all systems showed a significant percentage of recovered oil, with the anionic systems presenting the best results. A percentage of 80% recovery was reached, confirming the wettability study results, which pointed the influence of this property on the interaction of fluids and reservoir rock, and the ability of microemulsion systems to perform enhanced oil recovery in sandstone reservoirs.

A intera����o ensino-servi��o no processo de forma����o dos graduandos em fisioterapia da UFPB: a percep����o dos docentes

The health paradigm, consolidated in the last century, directed the training of health professionals, educated under the aegis of the Flexnerian training, fragmentary and hospital-centered model. However, it proved to be insufficient to meet the demands of the Unified Health System and the population. In this sense, the National Curriculum Guidelines for Undergraduate health courses emerge as a normative framework in proposing a new professional profile, as well as the recommendation of strategies for the restructuring of curricula and teaching practices, and one of them is the teaching-service integration. Therefore, the aim of this study was to investigate the process of training of Physiotherapy course students of the Federal University of Para��ba with the guiding principle of teaching-service integration, considering DCN. In this sense, the chosen method was a case study with qualitative approach. The sample was intentional, including all faculty members of the permanent staff of the Department of Physiotherapy at UFPB, linked to curriculum components whose practice scenarios occur in the SUS network and time longer than one year in that component. The data collection technique was the semi-structured interview. Data analysis was performed using the content analysis technique. The following categories were considered: professional training for SUS, integration of students to the SUS network services, the relationship between theory and practice in the training of physiotherapists, teaching and health professional partnership in the teaching-learning process and programs of training reorientation and their integration with the course. The results allowed identifying positive points in the teaching-service integration: recognition of the importance of integration activities between university and health services based on the insertion of students in the network, the combined actuation with health service professionals and the opportunity to work in a multidisciplinary team; the existence of structured and organized School Network; participation of students and teachers in government programs that offer the experience of insertion in the labor market. The following weaknesses stood out: difficulties in agreement, planning and evaluation of activities by the service; gap between theoretical and practical activities; lack of definition of roles of teacher and health service professionals in the training process and the fragile relationship of reorientation of vocational training programs with the curricular activities of the course. The teaching-service integration as a guiding principle in the analysis of the formation of physiotherapists reveals limits and possibilities for training that meets the health needs of the population. Thus, the choices of educational institutions regarding the care model have an influence on health practices, as well as the commitment by management and services and the permeability to social control instances decisively contribute to the improvement in the training of future professionals. Thus, the commitment of all involved for the effective change in the training process of health paradigm is indispensable.

A intera����o ensino-servi��o no processo de forma����o dos graduandos em fisioterapia da UFPB: a percep����o dos docentes

The health paradigm, consolidated in the last century, directed the training of health professionals, educated under the aegis of the Flexnerian training, fragmentary and hospital-centered model. However, it proved to be insufficient to meet the demands of the Unified Health System and the population. In this sense, the National Curriculum Guidelines for Undergraduate health courses emerge as a normative framework in proposing a new professional profile, as well as the recommendation of strategies for the restructuring of curricula and teaching practices, and one of them is the teaching-service integration. Therefore, the aim of this study was to investigate the process of training of Physiotherapy course students of the Federal University of Para��ba with the guiding principle of teaching-service integration, considering DCN. In this sense, the chosen method was a case study with qualitative approach. The sample was intentional, including all faculty members of the permanent staff of the Department of Physiotherapy at UFPB, linked to curriculum components whose practice scenarios occur in the SUS network and time longer than one year in that component. The data collection technique was the semi-structured interview. Data analysis was performed using the content analysis technique. The following categories were considered: professional training for SUS, integration of students to the SUS network services, the relationship between theory and practice in the training of physiotherapists, teaching and health professional partnership in the teaching-learning process and programs of training reorientation and their integration with the course. The results allowed identifying positive points in the teaching-service integration: recognition of the importance of integration activities between university and health services based on the insertion of students in the network, the combined actuation with health service professionals and the opportunity to work in a multidisciplinary team; the existence of structured and organized School Network; participation of students and teachers in government programs that offer the experience of insertion in the labor market. The following weaknesses stood out: difficulties in agreement, planning and evaluation of activities by the service; gap between theoretical and practical activities; lack of definition of roles of teacher and health service professionals in the training process and the fragile relationship of reorientation of vocational training programs with the curricular activities of the course. The teaching-service integration as a guiding principle in the analysis of the formation of physiotherapists reveals limits and possibilities for training that meets the health needs of the population. Thus, the choices of educational institutions regarding the care model have an influence on health practices, as well as the commitment by management and services and the permeability to social control instances decisively contribute to the improvement in the training of future professionals. Thus, the commitment of all involved for the effective change in the training process of health paradigm is indispensable.

Obten����o de triacetato de celulose a partir do baga��o de cana-dea����car para revestimento de micropart��culas de goma gelana e avalia����o do seu perfil de libera����o in vitro e da mucoades��o ex vivo

Oral route of administration is considered to be the most comfortable, safe and greater adaptation for patients. But, oral route presents some disadvantages such as drugs bioavailability and side effects on the stomach. Some technologies are studied to soften and/or resolve these problems, such as coating with polymeric films, which are able to protect the pharmaceutical form of the acid stomachic environment and to act in the drug release, and mucoadhesive systems, which allow the pharmaceutical form remains a greater time interval in the intestine, increasing the effectiveness of the drug. Cellulose triacetate (CTA) films were produced from cellulose extracted from sugar cane bagasse. The films were prepared with different morphologies (with and without water, acting as non-solvent) and concentrations (3, 6.5 and 10%) of CTA and characterized using scanning electron microscopy (SEM), water vapor permeability (WVP), puncture resistance (PR), enzymatic digestion (DE), and mucoadhesive force evaluation (MF). Microscopy showed the formation of symmetric and asymmetric morphologies. WVP data showed that more concentrated films have higher values for WVP; moreover, asymmetric films had higher values than symmetric films. PR measurements showed that symmetric membranes are more resistant than asymmetric ones. More concentrated films were also more puncture resistant, except for symmetric membranes with CTA concentrations of 6.5 and 10% that did not show significant differences. All of the films presented large mucoadhesive capacities independent of their morphology and CTA concentration. From the results of WVP and RP, a symmetric filme with 6.5% CTA showed better ability and mechanical resistance, therefore, was selected to serve as coating of gellan gum (GG) particles incorporating ketoprofen (KET), which was confirmed by SEM. The selected film presented low values in measurements of the swelling index (SI) and in a dissolution test (DT). TGA analysis showed that the CTA coating does not influence the thermal stability of the particles and there is no incompatibility evidence between CTA, GG and KET. Coated particles released 100% of the ketoprofen in 24 h, while uncoated particles released the same amount in 4 h. The results of this study highlight the potential of CTA in the development of new controlled oral delivery systems.

Isquemia P��lvica Aguda: uma Complica����o Fatal ap��s Tratamento Endovascular de Aneurisma Aorto-Il��aco com Pr��tese Ramificada da Il��aca

Introdu����o: A oclus��o da art��ria hipog��strica pode ser necess��ria na repara����o endovascular de aneurismas da aorta abdominal (EVAR). A oclus��o intencional da hipog��strica pode ter complica����es isqu��micas. As endopr��teses de bifurca����o il��aca (IBD) surgiram como alternativa endovascular �� oclus��o da hipog��strica em doentes com elevado risco para isquemia p��lvica. Os autores descrevem um caso de oclus��o precoce do ramo hipog��strico de IBD com graves consequ��ncias cl��nicas. Caso cl��nico: Sexo masculino, de 74 anos, com aneurisma da aorta abdominal (di��metro m��ximo de 55 mm) com envolvimento de ambas as bifurca����es il��acas e segmentos proximais das hipog��stricas (di��metro m��ximo de 31 e 32 mm), submetido a EVAR com revasculariza����o hipog��strica esquerda via IBD (Cook Zenith��) e coiling+overstenting da art��ria hipog��strica contralateral. O procedimento decorreu sem complica����es e a angiogra���a ���nal mostrava permeabilidade da hipog��strica revascularizada e escassa colateralidade p��lvica. O p��s-operat��rio imediato complicou-se de dor lombar e gl��tea bilateral associada a manifesta����es cut��neas isqu��micas e monoparesia do membro inferior esquerdo. Por agravamento progressivo nas primeiras 24h e angioTC com oclus��o do stent da hipog��strica esquerda, procedeu-se novamente a revasculariza����o da hipog��strica, com bom resultado na angiogra���a ���nal. Apesar da revasculariza����o bem-sucedida, houve agravamento progressivo do estado geral, com isquemia p��lvica irrevers��vel e rabdomi��lise. ��bito ao 5.���dia p��s-operat��rio. Conclus��o: A isquemia p��lvica aguda �� uma complica����o grave e frequentemente fatal que pode advir da oclus��o bilateral das art��rias hipog��stricas. A fal��ncia da revasculariza����o por IBD pode ser fatal, pelo que os autores aconselham um cuidado redobrado no controlo angiogr�����co ���nal e um baixo limiar para investiga����o na suspeita de complica����es p��s-operat��rias. Se maior risco de fal��ncia t��cnica, emboliza����o ou escassa colateralidade p��lvica, a preserva����o bilateral de ���uxo nas art��rias hipog��stricas pode estar recomendada.

Adequa����o bioclim��tica para os espa��os urbanos abertos do centro de Fortaleza, CE

This research presents a study investigating the correlation between the environmental-physycal charcateristics of cities and the formation of its micro-climates. The study was conducted in the central area of Fortaleza characterized as a stable and consolidated area, where the city originated and currently faces serious problems in its urban dynamics. The points of measurements were determined by the elaboration and analysis of topography maps, height of buildings, land use, type of surface coating and vegetation, following the methodology of Katzschner (1997). A zoning map was then determined, according to common morphological characteristics of the 12 measurement points, which were based on a set of Romero s (2001) bioclimatic criteria. Air measurements, temperature, humidity, intensity and direction of winds were made in transect form in two different circuits in the study area, with six points of data collection in each area, in three different times: 6:00 am, 1:00pm and 7:00pm, during two periods of the year: August 2008 and March 2009. The results verified the influence of different environmental-physical types in the behavior of the climatic variables that were collected. A verticaliza����o t��o condenada em algumas situa����es se bem equilibrada e controlada pode reduzir as temperaturas do ar atrav��s do sombreamento dos espa��os urbanos e possibilidade de maior permeabilidade a ventila����o natural. The highest average air temperature and lower humidity were recorded at the point I at all times. This situation may have been in result of the high density, poor vegetation and extended paving of the ground. According to the results, it s clear the positive influence vegetation has on easing air temperature. Another indicator observed that areas with a greater variation in building heights tend to present decreased average air temperature. High rise structure, planned in accordance to urban air quality parameters, can reduce air temperatures by the shading of urban spaces and the possibility of greater penetration of natural ventilation

Avalia����o da atividade antimicrobiana de filmes prot��icos a base de anchoita (engraulis anchoita) incorporados com ��cidos org��nicos.

Os filmes s��o produzidos a partir de macromol��culas, que podem ser utilizados como embalagem, como os polissacar��deos, lip��deos e prote��nas. As prote��nas se destacam dos demais, pois possuem uma estrutura com 20 mon��meros diferentes, que confere um amplo potencial de liga����es intermoleculares. A incorpora����o de agentes ativos em filmes �� uma alternativa como embalagem, para inibir ou retardar a multiplica����o de microrganismos pat��genos e deteriorantes em alimentos. O objetivo deste trabalho foi avaliar a atividade antimicrobiana de filmes �� base de isolado prot��ico de anchoita (Engraulis anchoita) ��� IPA adicionados de ��cidos org��nicos. Para tanto, foi elaborado o IPA, pela solubiliza����o alcalina da prote��na e precipita����o no ponto isoel��trico a partir de carne mecanicamente separada. O IPA foi avaliado quanto a sua composi����o proximal, aminoac��dica e por DSC. A solu����o formadora dos filmes foi elaborada a partir de IPA, ��gua, glicerol e hidr��xido de s��dio. As formula����es dos filmes foram elaboradas segundo um planejamento fatorial 23 . Foram avaliadas as propriedades f��sico-qu��micas de resist��ncia a tra����o (RT) e elonga����o (E); espessura, solubilidade e permeabilidade ao vapor de ��gua (PVA); a diferen��a de cor (���E*) e opacidade (Y) e microscopia eletr��nica de varredura (MEV) de filmes �� base de IPA. Os filmes com diferentes concentra����es de ��cido s��rbico (AS) ou ��cido benz��ico (AB) foram desenvolvidos a partir da condi����o cujo as propriedades f��sico-qu��micas foram as melhores, sendo comparados aos filmes controles. Estes, foram avaliados quanto a sua atividade antimicrobiana frente aos microrganismos Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus e Salmonella Enteritidis pelo m��todo de difus��o em disco, al��m das propriedades f��sico-qu��micas, MEV e FT-IV. Os filmes com maior atividade antimicrobiana e os filmes controle foram aplicados sobre carne bovina, inoculados com os microrganismos inibidos no m��todo de difus��o em disco e armazenados a 5��C. Estes, foram avaliados a cada 2 dias durante 12 dias de armazenamento, pela m��todo de contagem em gotas. O IPA apresentou 88,8% de prote��na e 53,3% de amino��cidos polares e temperatura de desnatura����o de 62,2��C. A espessura, PVA, ���E* e Y dos filmes n��o foram afetados pelas vari��veis estudadas no experimento. A menor solubilidade e maior RT dos filmes ocorreram em baixa concentra����o de IPA, glicerol e tratamento t��rmico, mas a E aumentou com o acr��scimo dessas vari��veis. As MEV das superf��cies dos filmes foram homog��neas, para aqueles com leve tratamento t��rmico. O aumento da concentra����o de AS e AB na faixa de 0,50 a 1,50% resultou na diminui����o da RT e aumento da E, solubilidade, ���E* e Y. Houve mudan��a da organiza����o molecular e intera����es intermoleculares entre as mol��culas de IPA e AB testados pela avalia����o do FT-IV. As MEV revelaram microporos em filmes com 1,50% de AS, o que resultou em filmes com menor homogeneidade. A maior atividade antimicrobiana foi verificada nos filmes com 1,50% de AS e AB frente a E. coli O157:H7, L. monocytogenes e S. Enteritidis. Estes filmes foram aplicados sobre carne bovina inoculada com E. coli O157:H7 e L. monocytogenes. Os filmes de AS frente a E. coli O157:H7 e L. monocytogenes apresentaram uma redu����o de 5 e 4 log UFC.g-1, respectivamente, em rela����o ao filme controle. O efeito do AB frente a estas bact��rias, apresentou uma redu����o de 6 e 5 log UFC.g-1, ao final do 12�� dia de armazenamento, respectivamente. Os filmes elaborados �� base de IPA, adicionados de AS ou AB podem ser eficazes contra os pat��genos alimentares testados.

Novas estrat��gias para entender o sistema de influxo de antibi��ticos e a resist��ncia antimicrobiana a n��vel molecular

As fluoroquinolonas s��o antibi��ticos que t��m um largo espectro de a����o contra bact��rias, especialmente Gram-negativas. O seu mecanismo de a����o assenta na inibi����o de enzimas respons��veis pela replica����o do DNA. Por��m, devido ao seu uso indevido, o surgimento de resist��ncia bacteriana a estes antibi��ticos tem-se tornado um grave problema de sa��de p��blica. Uma vez que os seus alvos de a����o se situam no meio intracelular, a redu����o da permeabilidade da membrana externa de bact��rias Gram-negativas constitui um dos mecanismos de resist��ncia mais conhecidos. Esta redu����o �� associada �� baixa express��o ou muta����es em porinas necess��rias para permitir o seu transporte, mais concretamente, da OmpF. Estudos pr��vios demonstraram que a coordena����o de fluoroquinolonas com i��es met��licos divalentes e 1,10-fenantrolina (genericamente designados metaloantibi��ticos) s��o potenciais candidatos como alternativa ��s fluoroquinolonas convencionais. Estes metaloantibi��ticos exibem um efeito antimicrobiano compar��vel ou superior �� fluoroquinolona na forma livre, mas parecem ter uma via de transloca����o diferente, independente de porinas. Estas diferen��as no mecanismo de captura podem ser fundamentais para contornar a resist��ncia bacteriana. De forma a compreender o papel dos l��pidos no mecanismo de entrada dos metaloantibi��ticos, estudou-se a intera����o e localiza����o dos metaloantibi��ticos da Ciprofloxacina (2�� gera����o), da Levofloxacina (3�� gera����o) e Moxifloxacina (4�� gera����o) com um modelo de membranas de Escherichia coli desprovido de porinas. Estes estudos foram realizados atrav��s de t��cnicas de espectroscopia de fluoresc��ncia, por medi����es em modo estacion��rio e resolvida no tempo. Os coeficientes de parti����o determinados demonstraram uma intera����o mais elevada dos metaloantibi��ticos relativamente ��s respetivas fluoroquinolonas na forma livre, um facto que est�� diretamente relacionado com as esp��cies existentes em solu����o a pH fisiol��gico. Os estudos de localiza����o mostraram que estes metaloantibi��ticos devem estar inseridos na membrana bacteriana, confirmando a sua entrada independente de porinas. Este mecanismo de entrada, pela via hidrof��bica, �� potenciado por intera����es eletrost��ticas entre as esp��cies cati��nicas de metaloantibi��tico que existem a pH 7,4 e os grupos carregados negativamente dos fosfol��pidos da membrana. Desta forma, os resultados obtidos neste estudo sugerem que a via de entrada dos metaloantibi��ticos e das respetivas fluoroquinolonas deve ser diferente. Os metaloantibi��ticos s��o candidatos adequados para a realiza����o de mais testes laboratoriais e uma alternativa promissora para substituir as fluoroquinolonas convencionais, uma vez que parecem ultrapassar um dos principais mecanismos de resist��ncia bacteriana a esta classe de antibi��ticos.