Hybrid materials from intermolecular associations between cationic lipid and polymers

Intermolecular associations between a cationic lipid and two model polymers were evaluated from preparation and characterization of hybrid thin films cast on silicon wafers. The novel materials were prepared by spin-coating of a chloroformic solution of lipid and polymer on silicon wafer. Polymers tested for miscibility with the cationic lipid dioctadecyldimethylammonium bromide (DODAB) were polystyrene (PS) and poly(methyl methacrylate) (PMMA). The films thus obtained were characterized by ellipsometry, wettability, optical and atomic force microscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and activity against Escherichia coli. Whereas intermolecular ion-dipole interactions were available for the PMMA-DODAB interacting pair producing smooth PMMA-DODAB films, the absence of such interactions for PS-DODAB films caused lipid segregation, poor film stability (detachment from the silicon wafer) and large rugosity. In addition, the well-established but still remarkable antimicrobial DODAB properties were transferred to the novel hybrid PMMA/DODAB coating, which is demonstrated to be highly effective against E. coli.

Identification of lift-off mechanism failure for salt drill-in drilling fluid containing polymer filter cake through adsorption/desorption studies

Drilling fluid`s contact with the productive zone of horizontal or complex wells can reduce well productivity by fluid invasion in the borehole wall. Salted drilling drill-in fluid containing polymers has often been applied in horizontal or complex petroleum wells in the poorly consolidated sandstone reservoirs of the Campos basin, Rio de Janeiro, Brazil. This fluid usually consists of natural polymers such as starch and xanthan gum, which are deposited as a filter cake on the wellbore wall during the drilling. Therefore, the identification of a lift-off mechanism failure, which can be detachment or blistering and pinholing, will enable formulation improvements. increasing the chances of success during filter cake removal in open hole operations. Likewise, knowledge of drill-in drilling fluid adsorption/desorption onto sand can help understand the filter cake-rock adhesion mechanism and consequently filter cake lift-off mechanism failures. The present study aimed to identify the lift-off failure mechanism for this type of fluid filter cake studying adsorption/desorption onto SiO(2) using solutions of natural polymers, lubricants, besides the fluid itself. Ellipsometry was employed to measure this process. The adsorption/desorption studies showed that the adsorbed layer of drilling fluid onto the walls of the rock pores is made up of clusters of polymers, linked by hydrogen bonds, which results in a force of lower cohesion compared to the electrostatic interaction between silica and polymers. Consequently, it was found that the most probable filter cake failure mechanism is rupture (blistering and pinholing), which results in the formation of ducts within the filter cake. (C) 2009 Elsevier B.V. All rights reserved.

On the activation and physical degradation of boron-doped diamond surfaces brought on by cathodic pretreatments

The electrochemical activation and physical degradation of boron-doped diamond (BDD) electrodes with different boron doping levels after repeated cathodic pretreatments are reported. Galvanostatic cathodic pretreatment passing up to -14000 C cm(-2) in steps of -600 C cm(-2) using -1 A cm(-2) caused significant physical degradation of the BDD surface, with film detachment in some areas. Because of this degradation, a great increase in the electrochemically active area was observed in Tafel plots for the hydrogen evolution reaction (HER) in acid media. The minimum cathodic pretreatment needed for the electrochemical activation of the BDD electrodes without producing any observable physical degradation on the BDD surfaces was determined using electrochemical impedance spectroscopy (EIS) measurements and cyclic voltammetry: -9 C cm(-2), passed at -1 A cm(-2). This optimized cathodic pretreatment can be safely used when electrochemical experiments are carried out on BDD electrodes with doping levels in the range between 800 and 8000 ppm.

Pesquisa de clima organizacional: uma análise crítica

The organization climate research is a widely used human resources tool grounded on the managerial discourse that preaches that listening to employees's opinions is relevant for the identification of corporate aspects that demand improvement. This study aims at desmistifying this discourse by means of analytical tools from the Critical Administration Studies, namely: denaturalized view of administration, detachment between intentions and performance and search for emancipation. The study is grounded on the assumption that the organizational climate research derives from functionalist theory, which benefits a dominating class, in name of productivity and for the maintenance of the status quo, therefore contributing for individual alienation at work. The study was designed to identify elements that show the relation between an organizational climate research tool and the social control over individuals in an organization - here the research conducted in 2005 by Centrais Elétricas Brasileiras S/A - Eletrobrás, the Brazilian power sector holding company. The theoretical section presents an overview of corporate paradigms relevant for a sound understanding of the organizational climate concept. Data analysis was conducted by means of the post-modern method of binary deconstruction: the questions contained in the tool's questionnaire were grouped into categories and then analyzed in terms of the fallowing conceptual pairs: well-being/productivity, autonomy/control, ethics/ competitiveness and participation/alienation. The analysis showed that the organization climate research tool is used as a resource for social control and power, because it contributes to individual alienation as it satisfies some specific individual demands, therefore preventing the individual form a thorough understanding of how the system works. Besides, the helps anticipate, mitigate and conceal the conflicts arising from the opposing interests of capital and labor.

O impacto da utilização da estrutura de listagem em BDR na precificação dos ativos após o evento Agrenco : uma análise em série temporal com quebra estrutural

Este trabalho tem por objetivo verificar o impacto que más práticas na gestão da Agrenco, empresa listada na bolsa de valores brasileira sob a forma de BDRs (Brazilian Depositary Receipts), trouxe para a precificação dos demais ativos listados sob a mesma estrutura. Estudos anteriores, como os de Saudagaran (1988) e Pagano (2001), focaram em temas referentes aos motivos que influenciaram as companhias a listarem suas ações em diferentes bolsas. Entender as conseqüências do evento Agrenco é importante para todos os participantes do mercado financeiro. O estudo contemplou uma amostra das principais empresas listadas sobre a forma de BDRs desde a data de seus IPOs até 26/08/2008. Primeiramente efetuou-se uma análise do comportamento gráfico dos preços dos ativos das BDRs listadas. Posteriormente elaborou-se três regressões múltiplas utilizando-se um modelo de série temporal (modelo AR – auto-regressivo), com análise de quebra estrutural e uso de variável Dummy. A primeira regressão relaciona a variável Agrenco com índices de BDRs constituídos especificamente para este estudo, a segunda inclui uma variável Dummy de intercepto e a terceira combina a variável Dummy de intercepto com uma variável Dummy de inclinação. As regressões têm o objetivo de se averiguar se o evento da Agrenco afetou sistematicamente os preços das ações listadas sob a mesma forma. A maior contribuição do estudo foi verificar que a má prática de gestão na Agrenco, listada sob a forma de BDR, contaminou o retorno de outras empresas que se utilizaram do mesmo veículo como fonte de captação de recursos. Os resultados apontaram, pela análise gráfica, que não houve um descolamento da valorização da maior parte das ações uma semana depois do anúncio dos problemas financeiros da Agrenco em relação a carteira téorica de mercado (IBOVESPA). Entretanto, os resultados dos testes econométricos apontaram que houve impacto do evento Agrenco sobre os retornos das ações listadas sob a forma de BDR.

O DOI-CODI carioca: memória e cotidiano no "Castelo do Terror"

O objetivo dessa dissertação é analisar a memória de seis ex-prisioneiros políticos do Destacamento de Operações de Informações-Centro de Operações de Defesa Interna do Rio de Janeiro (DOI-CODI/RJ), entrevistados recentemente, entre os anos de 2002 e 2004, sobre o cotidiano vivido nessa instituição em 1970. Naquele ano, dentro do Sistema de Segurança Interna (SISSEGIN), os DOI-CODI haviam sido criados e distribuídos por todas as Regiões Militares do país, tornando-se a principal instituição de repressão aos opositores políticos que optaram pela luta armada como forma de derrotar a ditadura militar brasileira. Assim, as narrativas desses seis ex-prisioneiros são, além de fontes essenciais, o principal objeto de estudo deste trabalho. Através delas, torna-se possível acessar aspectos cruciais para a caracterização do cotidiano vivido pelos presos em um desses órgãos, ― o DOI-CODI do Rio de Janeiro ―, uma vez que esse passado se liga ao presente por meio de suas memórias. Diante disso, a fim de melhor entender tais memórias, a formação e a atuação dos DOI-CODI também são aqui analisadas, colocando as narrativas dos ex-prisioneiros políticos entrevistados em diálogo com uma bibliografia especialmente selecionada, além de uma fonte a respeito do DOI feita por um de seus agentes quando este órgão ainda estava em atividade, em 1978. Para que a essas memórias seja aplicada uma crítica efetiva, necessária a todo trabalho histórico, o estudo se debruça ainda sobre as interferências que o presente exerce na construção que fazem com relação ao passado vivido no DOI-CODI/RJ, com o objetivo de esclarecer as bases sobre as quais são construídas cerca de trinta anos depois.

Avaliação de concretos reforçados por confinamento com manta de fibra de vidro estrutural e pré-impreganada

Due to the occurrence of diseases in the use of structural reinforcements in composites, with presentation of concrete blanket detachment, has been identified the need to evaluate the performance of concrete reinforced with glass fiber. This study aims to evaluate these concretes by means of testing methodologies, using concrete with low resistance with structural reinforcement for confinement by preimpregnated glass fiber and traditional fiberglass blanket. The first stage of work was the development of methodologies for analysis, opting for four types, such as the acoustic survey, strength to compressive, the pull-off and ultrasound. Next, tests were carried out using the four selected methodologies in 30 of proof-of-specimens by 5x10 cm, 15 were reinforced with the traditional fiberglass blanket with 5specimens exposed to test a marine environment of marine coastline of Natal-RN and 15 were reinforced with a pre-impregnated glass fiber blanket, as well as 5specimens exposed to a test environment of the marine coastline of Natal-RN. After conducting the acoustic survey, it has been verified a lack of delaminating and air bubbles in the samples, confirming the absence of gross shortcomings in the implementation of the ribs both the traditional fiberglass blanket and in the preimpregnated fiber glass blanket. After carrying out methods of pull-off and compressive strengthening test it was observed that the reinforced proof-bodies with pre-impregnated glass blanket showed maximum stresses higher than the traditional fiberglass blanket; consequently a greater grip with the formation of a smaller area of . fracture, unlike traditional glass mat, which showed lower maximum stresses, with a greater area of fracture. It was also found that the traditional fiberglass blanket presented detachment of blanket-concrete interface, unlike the pre-impregnated fiberglass blanket, which showed a better grip on the blanket-concrete interface. In the trial of ultrasound there was no presence of cracks in the blanket-concrete interface, yielding to both blankets good compactness of the concrete. At the end of this work, they were developed and proposed two methods of testing for evaluation of reinforced concrete structures with composites, for standardization, the acoustic survey and pull-off

Estudo da molhabilidade de ligas de adição à base de prata sobre insertos cerâmicos para aplicação em brocas perfuração de poços de petróleo

Metal-ceramic interfaces are present in tricone drill bits with hard ceramic inserts for oil well drilling operations. The combination of actions of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. Also the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. Wetting phenomena plays an essential role in the production of metal/ceramic interfaces when a liquid phase is present in the process. In this work, 72Silver-28Copper eutectic based brazing alloys were melted onto zirconia, silicon nitride and tungsten carbide/Co substrates under high vacuum. Contact angle evolution was measured and graphically plotted, and the interfaces produced were analysed by SEM-EDX. The AgCu eutectic alloy did not wet any ceramic substrates, showing high contact angles, and so without chemical interaction between the materials. Better results were found for the systemns containing 3%wt of titanium in the AgCu alloy. The presence os titanium as a solute in the alloy produces wettable cand termodinamically stable compounds, increasing the ceramics wetting beahviour

Cell Death in Salivary Glands of Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) Females at Semi-engorged Feeding Stage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Argamassas do grupo escolar Augusto Severo/RN: caracterização e incidência de manifestações patológicas

The search for cultural heritage preservation should be a constant, in order to minimize the lost of historical and cultural identity of a country. As part of this cultural heritage, highlights the importance of historical buildings. For the principles of restoration are met its important to know the state of conservation and the existing materials. Given the above, this work aims to study the pathological manifestations of the mortar coating from the Grupo Escolar Augusto Severo. For this, was conducted historical survey of the building, on-site visits with visual observation, collecting samples of mortar coating and characterization through visual and laboratory analysis, XRF, XRD, TG/DTG, OM and SEM-EDS. From the observations, pathological manifestations were found as: cracks, detachment of the coating, dirt, use of inappropriate material basis of cement, efflorescence, mold and mildew and also incompatible material base of cement. It was found that the pathological manifestations were intensified due to lack of coverage in some spots and especially the abandonment of the building, that many years does not have restoration or any other type of preventive and corrective maintenance. The results of laboratory tests indicated that the mortars studied are based on lime, with calcitic nature, and siliceous aggregate, with the presence of clay in two samples. From the samples collected, two are composed of lime, sand and clay and two by lime and sand. In this regard, it is important to conduct periodic inspections and maintenance, as well as carrying out restoration with use of material compatible with the original

Influência da corrente de pulso, do tempo de pulso e diâmetro de gota sobre a estabilidade da transferência metálica no processo MIG-P

To obtain a process stability and a quality weld bead it is necessary an adequate parameters set: base current and time, pulse current and pulse time, because these influence the mode of metal transfer and the weld quality in the MIG-P, sometimes requiring special sources with synergistic modes with external control for this stability. This work aims to analyze and compare the effects of pulse parameters and droplet size in arc stability in MIG-P, four packets of pulse parameters were analysed: Ip = 160 A, tp = 5.7 ms; Ip = 300 A and tp = 2 ms, Ip = 350 A, tp = 1.2 ms and Ip = 350 A, tp = 0.8 ms. Each was analyzed with three different drop diameters: drop with the same diameter of the wire electrode; droplet diameter larger drop smaller than the diameter of the wire electrode. For purposes of comparison the same was determined relation between the average current and welding speed was determined generating a constant (Im / Vs = K) for all parameters. Welding in flat plate by simple deposition for the MIG-P with a distance beak contact number (DBCP) constant was perfomed subsequently making up welding in flat plate by simple deposition with an inclination of 10 degrees to vary the DBCP, where by assessment on how the MIG-P behaved in such a situation was possible, in addition to evaluating the MIG-P with adaptive control, in order to maintain a constant arc stability. Also high speed recording synchronized with acquiring current x voltage (oscillogram) was executed for better interpretation of the transfer mechanism and better evaluation in regard to the study of the stability of the process. It is concluded that parameters 3 and 4 exhibited greater versatility; diameters drop equal to or slightly less than the diameter of the wire exhibited better stability due to their higher frequency of detachment, and the detachment of the drop base does not harm the maintenance the height of the arc

Aditivos de formulação na formação de filmes isolados de etilcelulose. estudos físico-químicos e morfológicos

Formulation Additives on Formation of Films isolated from Ethylcellulose. Physicochemical and Morphological Studies. In this work were developed free films from Surelease (R), additives alpha-GOS (alfa-glucooligosaccharide) and/or Tween (R) 80 in aqueous solution. It was obtained by Teflon plates casting process. The free films were characterized by thermal analysis (DSC and TGA), infrared spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). DSC and TO analysis showed that the additives do not influenced in the thermal stability of Surelease (R) films. SEM analysis observed homogeneous morphological characteristics and phase detachment absence. FTIR-ATR spectra were used to confirm the physical mixture between the components of films.

A educação em saúde pública na práqtica cotidiana: atuação dos cirurgiões-dentistas do PSF de Natal-RN

Considering education a support to health promotion, care integration and citizenship formation,the purpose of this research was to analyze the perception of the oral surgeons from the Family Health Program of Natal-RN over education in health as well as their performance as educators based on their activities on the program. A qualitative study was accomplished by a semi-structured interview and a Free Association of Words Test with 80 oral surgeons from the Family Health Program of Natal-RN. The instruments were analyzed through the meaning analysis and the Central Nucleus of Vergès Theory. The results showed a lack of planning in health actions so there is no standardization on the educative practices done by the oral surgeons which mostly are focused on scholars. There was an agreement among the group according to the oral surgeons´ perception about education in health that education is related to its function of recall prevention ideas to the population. Most part of the context units analyzed by the professionals´ speech show the knowledge of education in health as an inadequate behavior change instrument of the individuals. An interesting point was a quotation cited by some professionals that included actual themes such as citizenship, motivation and life quality, put inside the speech of education in health. To the oral surgeons the biggest difficulties on the development of the educative actions are due to the lack of incentive by the Municipal Health Bureau and to the detachment and lack of valorization of the themes by the population. The oral surgeons consider themselves co-responsible for the formation of a population which is able to request its health. They also mention the knowledge about the need of the community participation on the planning of the Family Health Program actions. Finally, it is notable the need for more encouragement so the oral surgeons can be more capable and have more interest in applying education in health on the perspective of a new model in health, because once capable and stimulated they can awake the population to education importance as a great transformation instrument for people searching for a fair, equalitarian and citizeness society

Structural analysis of the Pimelodus maculatus (Lacépède, 1803) embryogenesis (Siluriformes: Pimelodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experiências maternas de perda de um filho com câncer infantil: uma compreensão fenomenológico-existencial

Death due to childhood cancer reflects an early outcome of life, which can cause a strong repercussion in the mother s existence - figure to whom the greatest part of responsibilities during the child s illness is commonly allocated. The aim of this study is to understand the experience of mothers who have lost a kid as a consequence of childhood cancer, approaching the personal senses of this fact. Following a qualitative research design, with an exploratory and comprehensive approach, the study used the narrative method, which was obtained from a semi-structured interview, as the data generation procedure. The research counted on the participation of three adult mothers who had lost their kids because of childhood cancer, after - at least - a six-month period of oncologic treatment. The proposal of analysis follows the parameters of the phenomenological method and the data are based on Martin Heidegger s existential analytic. The results were structured into three thematic axes: previous History, child illness and its repercussions; The network of support and care; Loss and after loss: facing and signifying. It was possible to comprehend that the emergence of cancer in childhood promotes, since the diagnosis, a disruption of everyday meanings, accentuating the fragile condition of human life. In this specific circumstance of childhood illness, all the participants restricted their possibilities of being-in-the-world, dedicating exclusively to the practice of maternity. Concerning their relationship with their children in treatment, the narratives unveiled, in a convergent manner, the existence of care in a substitutive mode. In the network of support - primarily constituted by family, the health team and the support institutions - the relations were marked by proximity and detachment movements. With the child s death, mothers began to live a way of being-with the absent child , ensuring the continuity of the relationship with the dead infant. From the results exposed above, we can understand the motherly mourn as a singular experience in constant resignification, in which the subjective time overlaps the cronological time. The increment of anguish, resulting from the mother s confrontation to the question of finitude, mobilizes a process of change in their way of being-in-the-world, promoting an openness to new possibilities in their lives. Singular attention to the mother, during the process of illness and child loss, turns out to be fundamental