Showing papers by "Federal University of São Carlos published in 2006"
TL;DR: In this paper, the three crystalline phases of poly(vinylidene fluoride), α, β, and γ, have been obtained under distinct crystallization conditions, and the presence of the three phases in each sample were confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXD), polarized light optical microscopy (PLOM), and scanning electron microscopy(SEM).
Abstract: Samples containing the three crystalline phases of poly(vinylidene fluoride), α, β, and γ, have been obtained under distinct crystallization conditions. Samples containing exclusively unoriented β phase have been obtained by crystallization from dimethylformamide (DMF) solution at 60°C. Oriented β phase has been obtained by uniaxial drawing, at 80°C, of an originally α phase sample. Samples containing exclusively α phase have been obtained by melting and posterior cooling at room temperature. Samples containing both α and γ phases have been obtained by melt crystallization at 164 °C for 16 and 36 h. Presence of the crystalline phases in each sample were confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXD), polarized light optical microscopy (PLOM), and scanning electron microscopy (SEM). Infrared absorption bands identifying unequivocally the presence of β and γ phases in a sample are presented. It is shown that solution crystallization at T < 70°C always results in the β phase, regardless of the solvent used. Melt temperatures of the respective phases have also been determined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3272–3279, 2006
756 citations
TL;DR: The results showed that the gatherers have an accurate comprehension of tidal phenomenon based on their exploitation of natural resources, which perpetuates through generations.
Abstract: Traditional human communities have a wide knowledge of their environment. Collection of animals in estuarine and coastal areas are directly influenced by tidal cycles. The aim of this study is to evaluate the understanding of the tides associated with the lunar cycle held by people who gather crustaceans and molluscs in the State of Paraiba. The empirical knowledge of 20 crab gatherers and 30 mollusc gatherers was recorded through open interviews and structured questionnaires. The results showed that the gatherers have an accurate comprehension of tidal phenomenon based on their exploitation of natural resources, which perpetuates through generations.
411 citations
TL;DR: In this article, a plethora of relevant experimental results on internal homogeneous crystal nucleation in silicate glasses obtained in the last four decades, and their analyses in the framework of the classical nucleation theory (CNT) are outlined.
Abstract: We review a plethora of relevant experimental results on internal homogeneous crystal nucleation in silicate glasses obtained in the last four decades, and their analyses in the framework of the classical nucleation theory (CNT). The basic assumptions and equations of CNT are outlined. Particular attention is devoted to the analysis of the properties of the critical nuclei, which, to a large extent, govern nucleation kinetics. The main methods employed to measure nucleation rates are described and the possible errors in the determination of the crystal number density (and, correspondingly, in nucleation rates) are discussed. The basic regularities of both time and temperature dependencies of nucleation rates are illustrated by numerous experimental data. Experimental evidence for a correlation between maximum nucleation rates and reduced glass transition temperatures is presented and theoretically justified. Special attention is given to serious problems that arise in the quantitative description of nucleation rates when using the CNT, for instance: the dramatic discrepancy between calculated and measured nucleation rates; the high value of the crystal nuclei/melt surface energy, σcm, if compared to the expected value estimated via Stefan’s rule; the increase of σcm with increasing temperature; and the discrepancies between the values of the surface energy and the time-lag for nucleation when independently estimated from nucleation and growth kinetics. The analysis of the above mentioned problems leads to the following conclusion: in contrast to Gibbs’ description of heterogeneous systems underlying CNT, the bulk thermodynamic properties of the critical nuclei generally differ from those of the corresponding macro-phase resulting simultaneously in significant differences of the surface properties as compared with the respective parameters of the planar interfaces. In particular, direct experimental evidence is presented for compositional changes of the crystal nuclei during formation of the critical nuclei and their growth from critical to macro-sizes. In addition, detailed examinations of crystal nucleation and growth kinetics show a decrease of both the thermodynamic driving force for nucleation and of the critical nuclei/liquid interfacial energy, as compared with the respective properties of the macro-phase. However, despite significant progress in understanding crystal nucleation in glasses in the past four decades, many problems still exist and this is likely to remain a highly interesting subject for both fundamental and applied research for a long time.
378 citations
TL;DR: The current data suggest that MPc has oxidative-stress-inducing potential in fish, and that gills and white muscle are the most sensitive organs of B. cephalus, with poor antioxidant potentials.
Abstract: Methyl parathion (MP) is an organophosphorus insecticide used worldwide in agriculture and aquaculture due to its high activity against a broad spectrum of insect pests. The effect of a single exposure to 2 mg L − 1 of a commercial formulation of MP (MPc: Folisuper 600®, MP 600 g L − 1 ) on catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione S -transferase (GST), reduced glutathione (GSH) and lipid peroxidation (LPO) of the liver, white muscle and gills of Brycon cephalus was evaluated after 96 h of treatment. MPc exposure resulted in a significant induction of SOD, CAT and GST activity in all tissues. However, the GPx activity decreased significantly in white muscle and gills, whereas no alterations were observed in hepatic GPx activity. MPc also induced a significant increase in LPO values in the white muscle and gills, while hepatic LPO levels did not show any significant alteration. The current data suggest that MPc has oxidative-stress-inducing potential in fish, and that gills and white muscle are the most sensitive organs of B. cephalus , with poor antioxidant potentials. The various parameters studied in this investigation can also be used as biomarkers of exposure to MPc.
356 citations
TL;DR: In this article, the authors discuss the challenges of dealing with the contradiction of an imported ideology that represents an alignment to the latest fashion, but that at the same time can be used to overcome chronic problems of special education in the country.
Abstract: The debate about school inclusion in Brazil has become more and more a true collision, provoking controversy, stridency and polarization. One of the largest impacts is taking place in the arena of Special Education, in which one of the recurrent arguments is the proposition that deals with a new paradigm that should radically alter the education of children and youngsters with special educational needs in the Brazilian context. In order to "illuminate" rather than to "warm up" this debate, we intend, first, to contextualize the historical roots of the movement. Secondly, we examine the possible impacts of school inclusion and full inclusion on the Brazilian educational system. In conclusion, we discuss the thesis that we have to face the challenge of dealing with the contradiction of an imported ideology that represents an alignment to the latest fashion, but that at the same time can be one of the strategies used to overcome chronic problems of special education in the country.
283 citations
TL;DR: The research in developing countries shows that the emphasis is to demonstrate the usefulness of the entomopathogenic nematodes or their symbiotic bacteria against various pests, and the intensity of research varies by country or regions.
211 citations
TL;DR: In this article, the electrochemical response of the Fe(CN)64−/3− redox couple on boron-doped diamond (BDD) electrodes immediately after a cathodic pre-treatment and as a function of time exposed to atmospheric conditions is reported.
207 citations
TL;DR: The changes in hematological parameters of the fish, regardless of the pH and water temperature, indicate ionoregulatory or respiratory disturbances that imply an increase in energy consumption to restore homeostasis instead of other physiological functions such as weight gain and growth.
203 citations
TL;DR: In this article, the citrate-based perovskite was used in the CO 2 reforming of a methane reaction into synthesis gas, and the results showed that it exhibited activity to methane reforming, but suffered a slow deactivation with time-on-stream.
Abstract: Mixed oxides La 1− x Ce x NiO 3 ( x = 0, 0.05, 0.4 and 0.7) have been prepared by the citrate method and tested, after reduction activation, in the CO 2 reforming of methane reaction into synthesis gas. The compounds were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), specific surface area measurements, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM) and temperature-programmed oxidation (TPO). The LaNiO 3 perovskite exhibited activity to methane reforming, but suffered a slow deactivation with time-on-stream. Nevertheless, substitution of the A site metal ion with a tetravalent metal cation (Ce) led to an increase in catalytic activity. Moreover, the insertion of Ce increased the stability of the catalysts with respect to the reforming reaction. The La 0.95 Ce 0.05 NiO 3 catalyst showed the highest activity, with CO 2 conversion of 62% at 1023 K. The XRD and TPR analyses confirmed that at high Ce contents, ceria appears as segregated CeO 2 phase and interferes with the rate of perovskite structure formation, so that NiO and La 2 NiO 4 are produced. As a consequence of the low solubility of cerium oxide, its insertion in the perovskite structure is also possible in the low Ce-content regions. This low amount of cerium incorporated is responsible not only for the enhancement of catalytic performance of the perovskite after its activation by reduction, but also for the inhibition of carbon formation.
194 citations
TL;DR: In this paper, porous films in the β phase were obtained directly from the solution at 60 °C, after applying pressure perpendicular to the surface of the film at elevated temperature, the pores in the original sample were eliminated.
Abstract: Poly(vinylidene fluoride) (PVDF) has remarkable properties leading to electro-optics, electro-mechanical and biomedical applications. In particular, its piezo- and pyroelectric properties provide possibilities for many technological applications. The semicrystalline nature of PVDF, combined with the occurrence of at least four crystalline phases implies a complicated physical microstructure. The most frequently described and important phase is the β phase. The piezo- and pyroelectric properties mainly depend on this phase, so increasing the β phase content has always been a great concern. It is possible to obtain films in the β phase by solution but this material presents a high porosity leading to an opaque appearance and a decrease of the mechanical and electrical properties. In this work, porous films in the β phase were obtained directly from the solution at 60 °C. After applying pressure perpendicular to the surface of the film at elevated temperature, the pores in the original sample are eliminated. The changes on the morphology and crystallinity associated to the pressure treatment were also studied.
180 citations
TL;DR: The Brazilian Coffee Genome Project was designed with the objective of making modern genomics resources available to the coffee scientific community, working on different aspects of the coffee production chain.
Abstract: Coffee is one of the most valuable agricultural commodities and ranks second on international trade exchanges. The genus Coffea belongs to the Rubiaceae family which includes other important plants. The genus contains about 100 species but commercial production is based only on two species, Coffea arabica and Coffea canephora that represent about 70 % and 30 % of the total coffee market, respectively. The Brazilian Coffee Genome Project was designed with the objective of making modern genomics resources available to the coffee scientific community, working on different aspects of the coffee production chain. We have single-pass sequenced a total of 214,964 randomly picked clones from 37 cDNA libraries of C. arabica, C. canephora and C. racemosa, representing specific stages of cells and plant development that after trimming resulted in 130,792, 12,381 and 10,566 sequences for each species, respectively. The ESTs clustered into 17,982 clusters and 32,155 singletons. Blast analysis of these sequences revealed that 22 % had no significant matches to sequences in the National Center for Biotechnology Information database (of known or unknown function). The generated coffee EST database resulted in the identification of close to 33,000 different unigenes. Annotated sequencing results have been stored in an online database at http://www.lge.ibi.unicamp.br/cafe. Resources developed in this project provide genetic and genomic tools that may hold the key to the sustainability, competitiveness and future viability of the coffee industry in local and international markets.
TL;DR: In this article, the physical properties such as apparent densities, real densities and porosity of freeze-dried tropical fruits pulps such as pineapple, Barbados cherry, guava, papaya, and mango were evaluated.
Abstract: The objective of this work was to experimentally determine physical properties such as apparent densities, real densities, and porosity of freeze-dried tropical fruits pulps such as pineapple, Barbados cherry, guava, papaya, and mango, and to carry out nutritional analysis of vitamin C, calcium, and phosphorus in the freeze-dried and in natura pulps. The freeze-dried pulps presented low apparent density and elevated values of true density and porosity. Based on the nutritional analysis performed in the in natura and freeze-dried pulps the preservation of product quality was verified.
TL;DR: The program contributed towards maintaining hand grip strength over the two-year period, and the data indicate the need to reprogram the exercises aimed at developing this capacity.
Abstract: Influence of a Long-Term Physical Activity Program on Hand Muscle Strength and Body Flexibility Among Elderly Women Objective: The present study evaluated the influence of a two-year physical activity program on muscle strength and body flexibility among non-institutionalized elderly women (60-80 years old), from Salamanca Province in Spain. Method: Thirty-two individuals were chosen to take part in the Geriatric Revitalization Program at Salamanca University. The selection criteria were that they should be female, between 60 and 80 years old, with an attendance rate of at least 74% in the physical activity program. There were 174 physical activity sessions, over a 58-week period, three times a week, lasting 50-55 minutes each. During this period, four measurements of hand muscle strength were made, using a pressure manometer, and also of body flexibility, using the sit and reach test. The data were analyzed using ANOVA with repeated measurements. Results: There were no significant differences in relation to either muscle strength or flexibility (p=0.005). Conclusions: The program contributed towards maintaining hand grip strength over the two-year period. For body flexibility, the data indicate the need to reprogram the exercises aimed at developing this capacity.
TL;DR: It was seen that medicinal plants for this community represent an important factor in their maintenance of health care conditions, being part of a preserved local knowledge, and the transfer of ethno botanical knowledge follows traditional community patterns, without observed blockages.
Abstract: Trata-se de um estudo etnobotânico e pesquisa de opiniao, cujo objetivo e ampliar o conhecimento sobre a utilizacao de plantas medicinais pela comunidade do municipio de Cascavel - PR, visando subsidiar a implantacao dos fitoterapicos na rede publica de saude. A amostra correspondeu a 50 familias da area de abrangencia de uma Unidade Basica de Saude, selecionadas por amostragem estratificada proporcional. Para a obtencao dos dados optou-se pela pesquisa exploratorio-descritiva, utilizando-se entrevistas semi-estruturadas. Como resultado, observou-se que 96% da populacao amostrada indicou fazer uso de plantas; 271 referencias etnobotânicas foram registradas, englobando 75 etnoespecies; 40 propriedades terapeuticas estavam relacionadas ao uso domestico. A utilizacao de plantas e bastante difundida e a transferencia do conhecimento etnobotânico segue os padroes de comunidades tradicionais, nao havendo bloqueios neste processo. Constatou-se que as plantas medicinais para esta comunidade representam um fator importante para a manutencao das condicoes de saude, fazendo parte de um saber local preservado.
TL;DR: This review will focus on the structure, function and possible applications of the metalloprotease and disintegrin domains.
Abstract: Snake venoms are relevant sources of toxins that have evolved towards the engineering of highly active compounds. In the last years, research efforts have produced great advance in their understanding and uses. Metalloproteases with disintegrin domains are among the most abundant toxins in many Viperidae snake venoms. This review will focus on the structure, function and possible applications of the metalloprotease and disintegrin domains.
TL;DR: The rise in the hepatic activity of protein-metabolising enzymes in the fish fed high protein diets denoted effective use of dietary amino acids for growth and as a substrate for gluconeogenesis.
Abstract: This manuscript reports changes in key enzymes and metabolites related to protein metabolism and nitrogen excretion in the liver of juveniles jundia (Rhamdia quelen) fed on isocaloric diets containing 20%, 27%, 34% and 41% of crude protein. The hepatic activity of alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), glutamate dehydrogenase (GDH), and arginase (ARG) increased with the content of protein in the diet, and the ratios among the aminotransferases and GDH allowed evaluating metabolic preference. The concentration of free amino acids, ammonia and urea also rose with the dietary protein content. Increase of plasma urea and ammonia was the resultant effect of over amino acids catabolism as consequence of dietary protein surplus. Since the increase of protein in the diets resulted in weight gain, the rise in the hepatic activity of protein-metabolising enzymes in the fish fed high protein diets denoted effective use of dietary amino acids for growth and as a substrate for gluconeogenesis. Analysis of changes on metabolite levels and key enzyme activities in amino acid metabolism is proposed as a tool for assessing the proper balance of diet macronutrients.
TL;DR: The results indicated that the concentrations of ortho-phosphate, ammonium, total organic nitrogen, BOD5 and faecal coliforms characterized a pollution gradient along the river, where changes in the abundance or species composition were observed.
Abstract: The potential use of epilithic diatoms as indicators of organic pollution was evaluated in Gravatai River, RS, (latitude 29°45′–30°12′ S; longitude 50°27′–51°12′ W). The river suffers agricultural impacts in its upper course and urban and industrial organic pollution in its lower course. Epilithic diatoms were sampled eight times from September 2000 to August 2002, at six sites. Species were identified and densities and relative abundances of populations were determined. Simultaneously, physical, chemical and microbiological variables were measured (water temperature, conductivity, turbidity, pH, dissolved oxygen, biochemical oxygen demand (BOD5), chemical oxygen demand, ammonium, organic nitrogen, total nitrogen, ortho-phosphate, total phosphate, chloride and faecal coliforms). In order to interpret the environmental and biological variables, discriminant analysis and the TWINSPAN methods (Two-Way Indicator Species Analysis) were applied. The results indicated that the concentrations of ortho-phosphate, ammonium, total organic nitrogen, BOD5 and faecal coliforms characterized a pollution gradient along the river, where changes in the abundance or species composition were observed. Species were classified into three groups: Group A, including species more tolerant to heavy organic pollution and eutrophication, represented by Luticola goeppertiana, L. mutica, Eolimna subminuscula, Nitzschia palea and Sellaphora pupula; Group B, comprised of tolerant and widely distributed species such as Eunotia bilunaris, Frustulia crassinervia, F. saxonica, Navicula cryptocephala, N. cryptotenella, Nitzschia palea var. tenuirostris, Surirella angusta, Pinnularia microstauron and Ulnaria ulna and Group C, with less pollution tolerant species represented by Eunotia sp. and Gomphonema parvulum.
TL;DR: In this article, the structure properties of BaMoO4 powders were characterized by FTIR transmittance spectra, X-ray diffraction (XRD), Raman spectra and high-resolution scanning electron microscopy (HR-SEM).
TL;DR: The occurrence of toxic blooms in this reservoir points to a permanent risk of cyanotoxins in supply waters, indicating the need for the implementation of bloom control measures to improve the water quality.
Abstract: Nos relatamos a ocorrencia de florescimentos de cianobacterias e a presenca de cianotoxinas em amostras de agua do reservatorio Armando Ribeiro Goncalves (06° 08 S; 37° 07 W) situado no Estado do Rio Grande do Norte, na regiao semi-arida do Brasil. Cianobacterias foram identificadas e quantificadas nos periodos seco e chuvoso do ano 2000. Cianotoxinas tais como, microcistinas, saxitoxinas e cilindrospermopsinas foram quantificadas por HPLC e ELISA. Florescimentos toxicos mistos de Cylindrospermopsis raciborskii, Microcystis spp (M. panniformis, M. protocystis, M. novacekii) e Aphanizomenon ssp (Aphanizomenon gracile, A. cf. manguinii, A. cf. issastschenkoi) foram persistentes e representaram 90-100% da comunidade fitoplanctonica ao longo do periodo estudado. No periodo de chuvas, florescimentos toxicos de Cylindrospermopsis raciborskii coincidiram com maiores valores de saxitoxinas (3,14 µg.L-1). Entre o periodo de chuva e estiagem, ocorreram florescimentos toxicos de Microcytis spp, excedendo o valor minimo aceitavel para consumo humano (8,8 µg.L-1). Na estiagem, baixas concentracoes de saxitoxinas foram detectadas em florescimentos menos intensos com co-dominância de Cylindrospermopsis raciborskii, Microcystis spp e Aphanizomenon spp. Nossos resultados revelaram a presenca de microcistinas (8,8 µg.L-1) e saxitoxinas (3,14 µg.L-1) na agua bruta, a partir da segunda quinzena de abril ate o final de maio de 2000. A ocorrencia de blooms toxicos de cianobacterias no reservatorio em estudo aponta um risco permanente de cianotoxinas em aguas de abastecimento e indica a necessidade da implementacao de medidas de controle das floracoes, visando a melhoria da qualidade da agua. A exposicao das populacoes locais as cianotoxinas, pela sua potencial acumulacao em musculatura de peixes, tambem deve ser considerada.
TL;DR: In this article, the α to β phase transformation of PVDF through the stretching process at different temperatures was investigated and the optimum stretching conditions were studied and characterised by infrared spectroscopy and differential scanning calorimetry.
Abstract: The α to β phase transformation of PVDF through the stretching process at different temperatures was investigated. The optimum stretching conditions were studied and characterised by infrared spectroscopy and differential scanning calorimetry. The maximum β−phase content was achieved at 80°C and a stretch ratio of 5. Accompanying the phase transformation, a orientation of the polymer chains and a packing of the crystalline structure is observed. The stretch ratio does not significantly affect the degree of crystallinity.
TL;DR: The use of tetramethylammonium hydroxide, tertiary amines and strongly alkaline reagents for sample treatment involving extraction and digestion procedures is discussed in this paper.
TL;DR: The presence of the 5SHindIII-DNA sequences in the centromeres of several chromosomes indicates that this satellite family probably escaped from the selective pressure that maintains the structure and organization of the5S rDNA repeats and become disperse into the genome.
Abstract: A substantial fraction of the eukaryotic genome consists of repetitive DNA sequences that include satellites, minisatellites, microsatellites, and transposable elements. Although extensively studied for the past three decades, the molecular forces that generate, propagate and maintain repetitive DNAs in the genomes are still discussed. To further understand the dynamics and the mechanisms of evolution of repetitive DNAs in vertebrate genome, we searched for repetitive sequences in the genome of the fish species Hoplias malabaricus. A satellite sequence, named 5SHindIII-DNA, which has a conspicuous similarity with 5S rRNA genes and spacers was identified. FISH experiments showed that the 5S rRNA bona fide gene repeats were clustered in the interstitial position of two chromosome pairs of H. malabaricus, while the satellite 5SHindIII-DNA sequences were clustered in the centromeric position in nine chromosome pairs of the species. The presence of the 5SHindIII-DNA sequences in the centromeres of several chromosomes indicates that this satellite family probably escaped from the selective pressure that maintains the structure and organization of the 5S rDNA repeats and become disperse into the genome. Although it is not feasible to explain how this sequence has been maintained in the centromeric regions, it is possible to hypothesize that it may be involved in some structural or functional role of the centromere organization.
01 Apr 2006
TL;DR: This paper proposes two routing protocols: periodic, event-driven and query-based protocol (PEQ) and its variation CPEQ, two fault-tolerant and low-latency algorithms that meet sensor network requirements for critical conditions supervision in context-aware physical environments.
Abstract: Applications that require fine-grain monitoring of physical environments subjected to critical conditions, such as fire, leaking of toxic gases and explosions, pose a great challenge to sensor network protocols. These networks have to provide a fast, reliable, fault-tolerant and energy-aware channel for events diffusion, which meets the requirements of query-based, event-driven and periodic sensor networks application scenarios. These requirements have to be met even in the presence of emergency conditions that can lead to node failures and path disruption to the sink. This paper proposes two routing protocols: periodic, event-driven and query-based protocol (PEQ) and its variation CPEQ, two fault-tolerant and low-latency algorithms that meet sensor network requirements for critical conditions supervision in context-aware physical environments. While PEQ can provide low latency for event notification, fast broken path reconfiguration, and high reliability in the delivery of event packets for low-network data traffic, CPEQ is a cluster-based routing protocol that groups sensor nodes to efficiently relay the sensed data to the sink by uniformly distributing energy dissipation among the nodes and reducing latency for high-network data traffic (typical in emergency situations). PEQ and its variant CPEQ use the publish/subscribe paradigm to disseminate requests across the network. We discuss both PEQ and CPEQ protocols, their implementation, and report on the performance results of several scenarios using NS-2 simulator. The results obtained are compared with the well-known directed diffusion (DD) protocol, and show that our proposed algorithms exhibit a clear indication to meet the constraints and requirements of critical condition supervision in context-aware physical environments. Our results indicate that PEQ outperforms DD in the average delay since it uses the shortest path for the delivery of packets and speed up new subscriptions by using the reverse path used for event notification packets. CPEQ also outperforms DD in both the average delay and in the packet delivery ratio when the network scales up.
TL;DR: In this paper, a morte dos trabalhadores assalariados rurais, cortadores de cana, advem do pagamento por producao.
Abstract: O objetivo deste trabalho e demonstrar que a morte dos trabalhadores assalariados rurais, cortadores de cana, advem do pagamento por producao. Os processos de producao e de trabalho vigentes no Complexo Agroindustrial Canavieiro foram concebidos objetivando a produtividade crescente do trabalho e, combinados ao pagamento por producao, provocam a necessidade de os trabalhadores aumentarem o esforco despendido no trabalho. O crescimento do dispendio de energia e do esforco para cortar mais cana provoca ou a morte dos trabalhadores ou a perda precoce de capacidade de trabalho.
TL;DR: The history of the development of restricted-access media supports and of their application to the direct injection of biological fluid samples in high-performance liquid chromatography is presented.
Abstract: A quick overview of published methods for analyzing compounds in complex biological samples reveals that the most difficult step is the clean-up or extraction of a required compound from the matrix. The strategy required to analyze exogenous compounds in biological fluids depends greatly upon the nature of the compound and upon the biomatrix. Coupled-column separation using restricted-access media as the first dimension in order to exclude macromolecules and retain micromolecules has been successfully used for a number of biological fluids. This paper presents the history of the development of restricted-access media supports and of their application to the direct injection of biological fluid samples in high-performance liquid chromatography.
TL;DR: In this paper, the performance of the biocompatible alloys Ti-50Zr and Ti-13Nb-13Zr, as-cast and heat-treated, in distinct electrolytes (simulating or not physiological media: pH 7, Ringer, PBS, phosphate buffer and Na2SO4 solutions; pH 1, H 2SO4, HNO3, CH3SO3H, HClO4 and H3PO4 solutions) is reported.
TL;DR: In this article, the authors apply discrete simulation techniques to study the reception area processes of a sugarcane plant, analyzing the performance of the system and investigating alternative configurations and policies for its operations.
Abstract: An important aspect of logistics supply systems in agro industries is to manage the processes of harvesting and transporting raw materials, from the rural fields to the processing plants. The truck waiting times in the various queues of the plant reception area are of particular concern. This paper applies discrete simulation techniques to study the reception area processes of a sugarcane plant, analyzing the performance of the system and investigating alternative configurations and policies for its operations. The analysis is also useful for other agro industries with similar supply systems, such as orange and wood industries.
TL;DR: Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by downregulating matrix metallopeptidase activity, thus increasing the potential for tendon injury.
Abstract: BackgroundThe indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations.PurposeTo study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program.Study DesignControlled laboratory study.MethodsWistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animal's body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin–sodium dodecyl sulfate–polyacrylamide gel electrophoresis.ResultsMorphological analyses of tendons s...
TL;DR: In this article, the effect of different complexing agents on sensitivity was evaluated based on the formation of Co volatile compounds and a cloud point procedure was optimized for Co preconcentration for further improvement of sensitivity.
TL;DR: O objetivo deste estudo foi analisar, mediante revisao of literatura, os fatores de risco para nao-adesao a HAART, alem de agrupa-los e relaciona-los a pessoa em tratamento, a doenca, ao tratamentso e ao servico de saude e suporte social.
Abstract: A nao-adesao a terapeutica antiretroviral altamente eficaz (HAART) e considerada, no plano individual, como um dos mais ameacadores perigos para a efetividade do tratamento da pessoa com HIV/aids e para a disseminacao de virus-resistencia, no plano coletivo. Assim, o objetivo deste estudo foi analisar, mediante revisao de literatura, os fatores de risco para nao-adesao a HAART, alem de agrupa-los e relaciona-los a pessoa em tratamento, a doenca, ao tratamento e ao servico de saude e suporte social. A literatura aponta para a necessidade da realizacao de estudos que avaliem aspectos socioculturais, crencas, qualidade do servico prestado, relacoes do cliente com a equipe multiprofissional e outros referentes a raca e aos efeitos colaterais dos anti-retrovirais. Estes estudos visam a favorecer o estabelecimento de estrategias que melhorem a adesao dos clientes a HAART, ao mesmo tempo em e que contribuem para a construcao e exercicio da cidadania.