PS-HEMA latex fractionation by sedimentation and colloidal crystallization

A poly(styrene-co-hydroxyethylmethacrylate) latex underwent sedimentation under gravity followed by an spontaneous and extensive colloidal crystallization. It was then fractionated in three visually distinguishable layers. Latex aliquots layers were sampled at different heigths and the particles were characterized by PCS, microelectrophoresis, infrared spectra and analytical electron microscopy. The major fraction was opalescent and contained the colloidal crystals settled in the bottom of the liquid. Two other latex fractions were obtained, which differed in their chemical compositions, particle sizes and topochemical features from the self-arraying particles. Macrocrystallization of the fractionated latex yielded high quality crystals with a low frequency of defects, which confirms that particle chemical homogeneity is an important factor for particle self-arraying.Látex de poli(estireno-co-hidroxiacrilato de metila) separa-se em três camadas visualmente distinguíveis, das quais a inferior é opalescente e contém cristais coloidais. Alíquotas do látex foram coletadas em diferentes alturas, e as partículas foram caracterizadas, por espalhamento de luz dinâmico, microeletroforese, IV e microscopia eletrônica analítica. A fração inferior contém a maior parte do polímero, sendo formada por partículas de dimensões e composição química uniformes. As partículas coletadas das duas outras frações são diferentes das que formam os cristais coloidais, em praticamente todos os aspectos. A secagem da fração opalescente produz macrocristais de alta qualidade, com baixa frequência de defeitos, mostrando que a homogeneidade química das partículas é um fator importante, na sua auto-organização.497504Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Análise das dimensões do trabalho e o risco de adoecimento: um estudo na equipe de enfermagem das clínicas cirúrgicas de um hospital geral público

Dissertação apresentada ao Mestrado Profissional em Ensino em Ciências da Saúde da Universidade Federal de Rondônia-UNIR, como requisito final para a obtenção do título de Mestre em Ensino em Ciências da Saúde. Orientadora: Profa. Dra. Janne Cavalcante Monteiro.O presente estudo teve como objetivo geral investigar os fatores condicionantes da carga de trabalho e das condições ergonômicas do processo de trabalho que podem influenciar no adoecimento da equipe de enfermagem. Trata-se de um estudo descritivo com enfoque na abordagem quantitativa. Foi realizado com a equipe de enfermagem das clínicas cirúrgicas de um hospital geral público, com uma amostra de 71 sujeitos. A coleta de dados se deu através de questionário validado abordando as dimensões do trabalho cuja análise se fundamentou no referencial teórico da psicodinâmica do trabalho. Os dados sociodemográficos mostram que a equipe de enfermagem das clínicas cirúrgicas é predominantemente feminina, com média de idade de 40,8 anos, mais da metade da amostra é casada e o tempo médio de trabalho é de 5,4 anos. Apresentam renda salarial baixa e a grande maioria tem de dois a três dependentes financeiros, sendo os filhos os principais representantes dessa dependência e possuem mais de um vínculo empregatício. Os riscos de adoecimento foram investigados através do Inventário sobre o trabalho e riscos de adoecimento (ITRA), composto por quatro escalas interdependentes para avaliar quatro dimensões: contexto do trabalho, custo humano no trabalho, indicadores de prazer e sofrimento no trabalho e danos relacionados ao trabalho. Os resultados mostram que os profissionais apresentam uma avaliação negativa quanto a essas dimensões. Foram encontrados indicadores de adoecimento nesse estudo, evidenciados principalmente pela rigidez na organização do trabalho

The brain decade in debate: II. Panic or anxiety? From animal models to a neurobiological basis

This article is a transcription of an electronic symposium sponsored by the Brazilian Society of Neuroscience and Behavior (SBNeC). Invited researchers from the European Union, North America and Brazil discussed two issues on anxiety, namely whether panic is a very intense anxiety or something else, and what aspects of clinical anxiety are reproduced by animal models. Concerning the first issue, most participants agreed that generalized anxiety and panic disorder are different on the basis of clinical manifestations, drug response and animal models. Also, underlying brain structures, neurotransmitter modulation and hormonal changes seem to involve important differences. It is also common knowledge that existing animal models generate different types of fear/anxiety. A challenge for future research is to establish a good correlation between animal models and nosological classification.Universidade Federal do Paraná Departamento de Farmacologia Laboratório de Fisiologia e Farmacologia do Sistema Nervoso CentralUniversity of Hawaii Department of NeurobiologyUniversity of Hawaii Department of PsychologyUniversidade de São Paulo Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Departamento de PsicobiologiaUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de FisiologiaUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de NeuropsiquiatriaUniversidade Federal de Santa Catarina Departamento de FarmacologiaCentral Nervous System Research Department Sanofi SynthelaboAston University Institute of Pharmaceutical SciencesHoffmann-La Roche Ltd.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicologiaUniversity of Leeds Department of Psychology Ethopharmacology LaboratoryUniversidade Federal do Espírito Santo Centro de Biomedicina Departamento de Ciências FisiológicasUNIFESP, EPM, Depto. de PsicologiaSciEL

Stability of the monoclinic phase in the ferroelectric perovskite PbZr(1-x)TixO3

Recent structural studies of ferroelectric PbZr(1-x)TixO3 (PZT) with x= 0.48, have revealed a new monoclinic phase in the vicinity of the morphotropic phase boundary (MPB), previously regarded as the the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper, the stability region of all three phases has been established from high resolution synchrotron x-ray powder diffraction measurements on a series of highly homogeneous samples with 0.42 <=x<= 0.52. At 20K the monoclinic phase is stable in the range 0.46 <=x<= 0.51, and this range narrows as the temperature is increased. A first-order phase transition from tetragonal to rhombohedral symmetry is observed only for x= 0.45. The MPB, therefore, corresponds not to the tetragonal-rhombohedral phase boundary, but instead to the boundary between the tetragonal and monoclinic phases for 0.46 <=x<= 0.51. This result provides important insight into the close relationship between the monoclinic phase and the striking piezoelectric properties of PZT; in particular, investigations of poled samples have shown that the monoclinic distortion is the origin of the unusually high piezoelectric response of PZT.Comment: REVTeX file, 7 figures embedde

Raman Phonon Modes Of Zinc Blende Inxga1 - Xn Alloy Epitaxial Layers

Transverse-optical (TO) and longitudinal-optical (LO) phonons of zinc blende InxGa1 - xN (0≤x ≤0.31) layers are observed through first-order micro-Raman scattering experiments. The samples are grown by molecular-beam epitaxy on GaAs (001) substrates, and x-ray diffraction measurements are performed to determine the epilayer alloy composition. Both the TO and LO phonons exhibit a one-mode-type behavior, and their frequencies display a linear dependence on the composition. The Raman data reported here are used to predict the A1 (TO) and E1 (TO) phonon frequencies of the hexagonal InxGa1 - xN alloy. © 1999 American Institute of Physics.75810951097Pankove, J.I., Moustakas, T., Gallium nitrides I (1998) Semiconductors and Semimetals, 50. , Academic, San Diego, CAShan, W., Walukiewicz, W., Haller, E.E., Little, B.D., Song, J.J., McCluskey, M.D., Johnson, N.M., Stall, R.A., (1998) J. Appl. Phys., 84, p. 4452Chichibu, S., Azuhata, T., Sota, T., Nakamura, S., (1997) Appl. Phys. Lett., 70, p. 2822Shan, W., Perlin, P., Ager J.W. III, Walukiewicz, W., Haller, E.E., McCluskey, M.D., Johnson, N.M., Bour, D.P., (1998) Appl. Phys. Lett., 73, p. 1613Chichibu, S., Azuhata, T., Sota, T., Nakamura, S., (1996) Appl. Phys. Lett., 69, p. 4188Narukawa, Y., Kawakami, Y., Funato, M., Fujita, S., Nakamura, S., (1997) Appl. Phys. Lett., 70, p. 981Orton, J.W., Foxon, C.T., (1998) Rep. Prog. Phys., 61, p. 1Abernathy, C.R., MacKenzie, J.D., Bharatan, S.R., Jones, K.S., Pearton, S.J., (1995) Appl. Phys. Lett., 66, p. 1632(1995) J. Vac. Sci. Technol. A, 13, p. 716Müllhäuser, J.R., Jenichen, B., Wassermeier, M., Brandt, O., Ploog, K.H., (1997) Appl. Phys. Lett., 71, p. 909Müllhäuser, J.R., Brandt, O., Trompert, A., Jenichen, B., Ploog, K.H., (1998) Appl. Phys. Lett., 73, p. 1230Holst, J., Hoffmann, A., Broser, I., Frey, T., Schöttker, B., As, D.J., Schikora, D., Lischka, K., (1999) MRS Internet J. Nitride Semicond. Res., 4 S1, pp. G23Feng, Z.C., Schurman, M., Tran, C.A., Salagaj, T., Karlicek, B., Ferguson, I., Stall, R.A., Pitt, G.D., (1998) Mater. Sci. Forum, 264-268, p. 1359Behr, D., Niebuhr, R., Obloh, H., Wagner, J., Bachem, K.H., Kaufmann, U., (1997) Mater. Res. Soc. Symp. Proc., 468, p. 213Osamura, K., Naka, S., Murakami, Y., (1975) J. Appl. Phys., 46, p. 3432Tabata, A., Lima, A.P., Teles, L.K., Scolfaro, L.M.R., Leite, J.R., Lemos, V., Schöttker, B., Lischka, K., (1999) Appl. Phys. Lett., 74, p. 362Tabata, A., Enderlein, R., Leite, J.R., Da Silva, S.W., Galzerani, J.C., Schikora, D., Kloidt, M., Lischka, K., (1996) J. Appl. Phys., 79, p. 4137Strite, S., Chandrasekhar, D., Smith, D.J., Sariel, J., Chen, H., Teraguchi, N., Morkoç, H., (1993) J. Cryst. Growth, 127, p. 204Ho, I., Stringfellow, G.B., (1996) Appl. Phys. Lett., 69, p. 2701Inushima, T., Yaguchi, T., Nagase, A., Iso, A., Shiraishi, T., (1996) Proceedings of the 6th Conference on Silicon Carbide and Related Materials, , Bristol(1996) Inst. Phys. Conf. Ser., 142, p. 971Dyck, J.S., Kash, K., Kim, K., Lambrecht, W.R.L., Hayman, C.C., Argoitia, A., Grossner, M.T., Angus, J.C., (1998) Mater. Res. Soc. Symp. Proc., 482, p. 549Yu, S., Kim, K.W., Bergman, L., Dutta, M., Stroscio, M.A., Zavada, J.M., (1998) Phys. Rev. B, 58, p. 15283Kwon, H.-J., Lee, Y.-H., Miki, O., Yamano, H., Yoshida, A., (1996) Appl. Phys. Lett., 69, p. 937Lee, M.-C., Lin, H.-C., Pan, Y.-C., Shu, C.-K., Ou, J., Chen, W.-H., Chen, W.-K., (1998) Appl. Phys. Lett., 73, p. 260

A promyelocytic leukemia protein-thrombospondin 2 axis and the risk of relapse in neuroblastoma

Purpose. Neuroblastoma is a childhood malignancy originating from the sympathetic nervous system with a complex biology, prone to metastasize and relapse. High-risk, metastatic cases are explained in part by amplification or mutation of oncogenes such as MYCN and ALK and loss of tumour suppressor genes in chromosome band 1p. However, it is fundamental to identify other pathways responsible for the large portion of neuroblastomas with no obvious molecular alterations. Experimental design. Neuroblastoma cell lines were used for assessment of tumour growth in vivo and in vitro. Protein expression in tissues and cells was assessed using immunofluorescence and immunohistochemistry. The association of PML expression with neuroblastoma outcome and relapse was calculated using log-rank and Mann-Whitney tests, respectively. Gene expression was assessed using chip microarrays. Results: PML is detected in the developing and adult sympathetic nervous system, whereas it is not expressed or low in metastatic neuroblastoma tumours. Reduced PML expression in patients with low-risk cancers - i.e. localized and negative for the MYCN protooncogene - is strongly associated with tumour recurrence. PML-I, but not PML-IV, isoform suppresses angiogenesis via upregulation of thrombospondin-2 (TSP-2), a key inhibitor of angiogenesis. Finally, PML-I and TSP-2 expression inversely correlates with tumour angiogenesis and recurrence in localized neuroblastomas. Dvorkina et al. A promyelocytic leukaemia protein-thrombospondin 2 axis and the risk of relapse in neuroblastoma 3 Conclusions: Our work reveals a novel PML-I-TSP2 axis for regulation of angiogenesis and cancer relapse, which could be used to identify patients with low-risk, localized tumours that might benefit from chemotherapy