Micro-raman spectroscopic characterization of a CR-39 detector

Characterization by micro-Raman spectroscopy of polymeric materials used as nuclear track detectors reveals physico-chemical and morphological information on the material's molecular structure. In this work, the nuclear track detector poly(allyl diglycol carbonate), or Columbia Resin 39 (CR-39), was characterized according to the fluence of alpha particles produced by a 226Ra source and chemical etching time. Therefore, damage of the CR-39 chemical structure due to the alpha-particle interaction with the detector was analyzed at the molecular level. It was observed that the ionization and molecular excitation of the CR-39 after the irradiation process entail cleavage of chemical bonds and formation of latent track. In addition, after the chemical etching, there is also loss of polymer structure, leading to the decrease of the group density C-O-C (∼888 cm-1), CH=CH (∼960 cm -1), C-O (∼1110 cm-1), C-O-C (∼1240 cm -1), C-O (∼1290 cm-1), C-O (∼1741 cm -1), -CH2- (∼2910 cm-1), and the main band -CH2- (∼2950 cm-1). The analyses performed after irradiation and chemical etching led to a better understanding of the CR-39 molecular structure and better comprehension of the process of the formation of the track, which is related to chemical etching kinetics. Copyright © 2013 Society for Applied Spectroscopy.

A heuristic algorithm based on multi-assignment procedures for nurse scheduling

This paper tackles a Nurse Scheduling Problem which consists of generating work schedules for a set of nurses while considering their shift preferences and other requirements. The objective is to maximize the satisfaction of nurses' preferences and minimize the violation of soft constraints. This paper presents a new deterministic heuristic algorithm, called MAPA (multi-assignment problem-based algorithm), which is based on successive resolutions of the assignment problem. The algorithm has two phases: a constructive phase and an improvement phase. The constructive phase builds a full schedule by solving successive assignment problems, one for each day in the planning period. The improvement phase uses a couple of procedures that re-solve assignment problems to produce a better schedule. Given the deterministic nature of this algorithm, the same schedule is obtained each time that the algorithm is applied to the same problem instance. The performance of MAPA is benchmarked against published results for almost 250,000 instances from the NSPLib dataset. In most cases, particularly on large instances of the problem, the results produced by MAPA are better when compared to best-known solutions from the literature. The experiments reported here also show that the MAPA algorithm finds more feasible solutions compared with other algorithms in the literature, which suggest that this proposed approach is effective and robust. © 2013 Springer Science+Business Media New York.

Structure control of poly(p-phenylene vinylene) in layer-by-layer films by deposition on a charged poly(o-methoxyaniline) cushion

In this paper, we demonstrate that the intrinsic electric field created by a poly(o-methoxyaniline) (POMA) cushion layer hinders the changes in molecular conformation of poly(p-phenylenevinylene) (PPV) in layer-by-layer with dodecylbenzene sulfonic acid (DBS). This was modeled with density functional theory (DFT) calculations where an energy barrier hampered molecular movements of PPV segments when they were subjected to an electric field comparable to that caused by a charged POMA layer. With restricted changes in molecular conformation, the PPV film exhibited Franck-Condon transitions and the photoexcitation spectra resembled the absorption spectra, in contrast to PPV/DBS films deposited directly on glass, with no POMA cushion. Other effects from the POMA cushion were the reduced number of structural defects, confirmed with Raman spectroscopy, and an enhanced PPV emission at high temperatures (300 K) in comparison with the films on bare glass. The positive effects from the POMA cushion may be exploited for enhanced opto-electronic devices, especially as the intrinsic electric field may assist in separating photoexcited electron-hole pairs in photovoltaic devices. © 2013 American Institute of Physics.

SERS mapping in langmuir-blodgett films and single-molecule detection

Plasmon-enhanced spectroscopic techniques have expanded single-molecule detection (SMD) and are revolutionizing areas such as bio-imaging and single-cell manipulation. Surface-enhanced (resonance) Raman scattering (SERS or SERRS) combines high sensitivity with molecularfingerprint information at the single-molecule level. Spectra originating from single-molecule SERS experiments are rare events, which occur only if a single molecule is located in a hot-spot zone. In this spot, the molecule is selectively exposed to a significant enhancement associated with a high, local electromagnetic field in the plasmonic substrate. Here, we report an SMD study with an electrostatic approach in which a Langmuir film of a phospholipid with anionic polar head groups (PO 4 -) was doped with cationic methylene blue (MB), creating a homogeneous, two-dimensional distribution of dyes in the monolayer. The number of dyes in the probed area of the Langmuir-Blodgett (LB) film coating the Ag nanostructures established a regime in which single-molecule events were observed, with the identification based on direct matching of the observed spectrum at each point of the mapping with a reference spectrum for the MB molecule. In addition, advanced fitting techniques were tested with the data obtained from micro-Raman mapping, thus achieving real-time processing to extract the MB single-molecule spectra. © 2013 Society for Applied Spectroscopy.

Molecularly designed layer-by-layer (LbL) films to detect catechol using information visualization methods

The control of molecular architectures has been exploited in layer-by-layer (LbL) films deposited on Au interdigitated electrodes, thus forming an electronic tongue (e-tongue) system that reached an unprecedented high sensitivity (down to 10-12 M) in detecting catechol. Such high sensitivity was made possible upon using units containing the enzyme tyrosinase, which interacted specifically with catechol, and by processing impedance spectroscopy data with information visualization methods. These latter methods, including the parallel coordinates technique, were also useful for identifying the major contributors to the high distinguishing ability toward catechol. Among several film architectures tested, the most efficient had a tyrosinase layer deposited atop LbL films of alternating layers of dioctadecyldimethylammonium bromide (DODAB) and 1,2-dipalmitoyl-sn-3-glycero-fosfo-rac-(1-glycerol) (DPPG), viz., (DODAB/DPPG)5/DODAB/Tyr. The latter represents a more suitable medium for immobilizing tyrosinase when compared to conventional polyelectrolytes. Furthermore, the distinction was more effective at low frequencies where double-layer effects on the film/liquid sample dominate the electrical response. Because the optimization of film architectures based on information visualization is completely generic, the approach presented here may be extended to designing architectures for other types of applications in addition to sensing and biosensing. © 2013 American Chemical Society.

Tuning the nanostructure of DODAB/nickel tetrasulfonated phthalocyanine bilayers in LbL films

Nanostructured films of dioctadecyldimethylammonium bromide (DODAB) and nickel tetrasulfonated phthalocyanine (NiTsPc) were layer-by-layer (LbL) assembled to achieve a synergistic effect considering the distinct properties of both materials. Prior to LbL growth, the effect of NiTsPc on the structure of DODAB vesicles in aqueous medium was investigated by differential scanning calorimetry (DSC). Therefore, DODAB/NiTsPc LbL films were prepared using NiTsPc at concentrations below and above the limit concentration of vesicle formation according to our DSC experiments. As a result, LbL films with distinct nanostructures were obtained, which were studied at micro and nanoscales by micro-Raman and atomic force microscopy, respectively. A linear growth of the LbL films was observed by ultraviolet-visible absorption spectroscopy. However, the bilayer thickness and the surface morphology of the LbL films were radically affected depending on NiTsPc concentration. The electrostatic interaction between DODAB and NiTsPc was identified via Fourier transform infrared (FTIR) absorption spectroscopy as the main driving force responsible for LbL growth. Because LbL films have been widely applied as transducers in sensing devices, DODAB/NiTsPc LbL films having distinct nanostructures were tested as proof-of-principle in preliminary sensing experiments toward dopamine detection using impedance spectroscopy (e-tongue system). The real capacitance vs. dopamine concentration curves were treated using Principal Component Analysis (PCA) and an equivalent electric circuit, revealing the role played by the LbL film nanostructure and the possibility of building calibration curves. © 2013 Elsevier B.V.

Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers

Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with natural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcutaneous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was evaluated by histomorphometry of the inflammatory cells. Chemical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron microscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflammatory pattern, characterized by a reduction of polymorphonuclear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal-Wallis). On day 60, microscopic analysis showed regression of the chronic inflammatory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the medium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1284-1293, 2013. Copyright © 2013 Wiley Periodicals, Inc.

Disputa territorial entre o movimento camponês e o agronegócio canavieiro em Teodoro Sampaio–SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Apreciação de gêneros musicais no contexto do ensino médio: possíveis percursos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sofistas e filósofos na administração imperial: o olhar de Eunápio sobre a unidade política do império Romano no século IV D. C

Pós-graduação em História - FCHS

Infecção experimental em caprinos infectados com Trypanosoma evansi Steel, 1885 (Sarcomastigophora: Trypanosomatidae)

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

Acolhimento institucional em tempos de mudança: uma questão em análise

Promulgado em 1990, o Estatuto da Criança e do Adolescente (ECA) introduziu novas formas de compreensão da infância e da adolescência e novos modos de atendimento àqueles em situação de risco. Mas, segundo Adriane Vasti Gonçalves Negrão e Elizabeth Piemonte Constantino, autoras do livro Acolhimento institucional em tempos de mudança - uma questão em análise, a efetivação das novas políticas de assistência tem sido deficiente em vários aspectos, como o que tange à aplicação da medida de proteção de abrigo em entidades de acolhimento institucional. O trabalho das autoras foi embasado em pesquisa de campo e constatou que, apesar dos importantes esforços para atender os direitos previstos legalmente, são notórias as oscilações entre práticas e concepções pré e pós a promulgação do ECA. Alguns princípios ainda estão ancorados no mais puro assistencialismo, o qual não pressupõe crianças e adolescentes como cidadãos de direitos, mas sim como objetos de ações de caridade. São práticas ainda comuns a falta de incentivo ao convívio familiar e comunitário e os longos períodos de acolhimento institucional como resultado de decisões que não o justificam, cenário com o potencial de fragilizar ou impedir ações de caráter emancipatório das crianças e jovens. O livro sinaliza que existe ainda um longo percurso rumo às transformações das instituições que atendem crianças e adolescentes em situações de vulnerabilidade social.

Apreciação de gêneros musicais na escola: possíveis percursos

Paulo Roberto Prado Constantino dirige-se, neste livro, aos educadores que atuam especificamente no ensino médio, apresentando algumas propostas para o desenvolvimento da capacidade de apreciação e de compreensão musical entre os alunos. De acordo com o autor, a obrigatoriedade do ensino de Música nas escolas de educação básica, prevista em lei federal aprovada em 2008, trouxe uma série de problemas para os professores da disciplina, que se viram às voltas com a falta de recursos materiais e de ferramentas metodológicas de apoio à prática docente. Baseado em pesquisa de campo, Constantino parte da constatação de que se tornou impossível para os professores de Música desempenhar seu papel sem levar em conta a enorme exposição dos jovens aos gêneros musicais de massa e às novas mídias. E conclui que, se podem ser considerados vulgares do ponto de vista do conceito clássico de qualidade musical, tais gêneros também podem, se bem trabalhados em sala de aula, transportar os alunos para um universo musicalmente mais rico. O autor propõe um processo de ensino baseado no estudo e nas comparações entre os gêneros musicais, sem delimitações de fronteiras étnicas ou culturais ou entre o erudito e o popular, o elitizado e o massificado. Dessa forma, ele acredita, os alunos podem apreender todas as manifestações musicais como significativas e seguir adiante no aprendizado com maior compreensão do que seria o fenômeno musical, já que se evita deslegitimar a música do outro, por meio da imposição de uma visão única.

Prática esportiva e participação nas aulas de educação física: fatores associados em estudantes de Londrina, Paraná, Brasil

O objetivo deste estudo foi analisar os fatores associados à prática esportiva e participação nas aulas de educação física. A amostra foi composta por 827 jovens, selecionados em dois estágios e estratificados por região da cidade de Londrina, Paraná, Brasil. Foram analisadas a prática esportiva, participação nas aulas de educação física e variáveis sociodemográficas, comportamentais e ambientais. Os fatores associados à participação nas aulas de educação física foram: sexo masculino, idade (10-13 anos), percepção de atividade física igual ou elevada, prática esportiva, movimentação durante as aulas e realizar aulas na quadra. Para a prática esportiva, os fatores associados foram o sexo masculino, idade (10-13 anos), percepção de atividade física igual/elevada, atividade física (≥ 7horas/semana), participação nas aulas de educação física, possuir ≥ 10 amigos, prática de esportes com amigos e frequência de utilização de lugares para a prática. Esses fatores devem ser considerados nos programas de incentivo à prática esportiva e à participação nas aulas de educação física.

O ensino da escrita e o desenvolvimento das pessoas com deficiência intelectual

This article proposes a theoretical reflection on the development of children with intellectual disabilities, regarding the importance and necessity of the process of learning the written language, from a historical-cultural point of view. For this approach, the course of development of a child disabled or not will occur according to cultural and social conditions experimented by him or her. Therefore, concerning the child with intellectual disabilities, his cultural condition, in dynamic relationship with the obstacles placed in its special condition, will be the source of his development. If the development of higher psychological functions is realized through the use of tools and if the people with intellectual disabilities present an inability to use these tools, there will be the need for aids so they can learn to use them in order to train and develop their psychic functions. In this process, education and written language acquisitions are fundamental ways of accessibility to the cultural world, a wider significance of communication in the world and to oneself. In short, the educators' comprehension about the importance of intentional teaching of written language and the historical process that envolves its development represents a fundamental contribution to the process of humanization of children with disabilities.