Análise bibliométrica da produção científica brasileira de RH na década de 1990 - um mapeamento a partir das citações dos artigos publicados no ENANPAD

Neste artigo, é usada análise bibliométrica para entender a influência de autores e instituições na produção acadêmica em Recursos Humanos no Brasil na década de 90, bem como para mapear o comportamento de auto-citações e citações à própria instituição dos autores que produziram no período. O estudo levantou, nos 290 artigos de RH publicados na década de 90 (1991 a 2000) nos anais do Enanpad, a constituição, origem e padrão de interrelação de todas as citações, autores e instituições que publicaram e foram citados na área. No total, analisaram-se os padrões bibliométricos de 5814 citações, que compreendiam 342 autores, advindos de 51 instituições. Os resultados mostram uma área com alto índice de auto-citação e endogenia, e com uma elevada incidência de citação de jornais, revistas e autores estrangeiros e não acadêmicos; revelam também que Maria Tereza Fleury (FEA/USP) foi a acadêmica mais citada; que a USP, UFMG, UFRGS e a FGV-EAESP (nessa ordem) são as instituições com os autores mais citados; que a RAE é o veículo nacional mais referenciado no campo; e que alguns autores e instituições que publicaram no período têm elevada propensão à auto-citação e à consulta predominante a autores de sua própria instituição. O artigo termina oferecendo ao campo sugestões para desenvolvimento e debate, a partir dos seus resultados e sua comparação com trabalhos anteriores analisando a mesma base amostral.

Novel catalyst systems based on Ni(II), Ti(IV), and Cr(III) complexes for oligo-and polymerization of ethylene

The complex of Brookhart Ni(α-diimine)Cl2 (1) (α-diimine = 1,4-bis(2,6- diisopropylphenyl)-acenaphthenediimine) has been characterized after impregnation on silica (S1) and MAO-modified silicas (4.0, 8.0 and 23.0 wts.% Al/SiO2 called S2, S3 and S4, respectively). The treatment of these heterogeneous systems with MAO produces some active catalysts for the polymerization of the ethylene. A high catalytic activity has been gotten while using the system supported 1/S3 (196 kg of PE/mol[Ni].h.atm; toluene, Al/Ni = 1000, 30ºC, 60 min and atmospheric pressure of ethylene). The effects of polymerization conditions have been tested with the catalyst supported in S2 and the best catalytic activity has been gotten with solvent hexane, MAO as cocatalyst, molar ratio Al/Ni of 1000 and to the temperature of 30°C (285 kg of PE/mol[Ni].h.atm). When the reaction has been driven according to the in situ methodology, the activity practically doubled and polymers showed some similar properties. Polymers products by the supported catalysts showed the absence of melting fusion, results similar to those gotten with the homogeneous systems by DSC analysis. But then, polymers gotten with the transplanted system present according to the GPC’s curves the polydispersity (MwD) varies between 1.7 and 7.0. A polyethylene blend (BPE/LPE) was prepared using the complex Ni(α-diimine)Cl2 (1) (α-diimine = 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and {TpMs*}TiCl3 (2) (TpMs* = hydridobis(3-mesitylpyrazol-1-yl)(5-mesitylpyrazol-1-yl)) supported in situ on MAO-modified silica (4.0 wts. -% Al/SiO2, S2). Reactions of polymerization of ethylene have been executed in the toluene in two different temperatures (0 and 30°C), varying the molars fraction of nickel (xNi), and using MAO as external cocatalyst. To all temperatures, the activities show a linear variation tendency with xNi and indicate the absence of the effect synergic between the species of nickel and the titanium. The maximum of activity have been found at 0°C. The melting temperature for the blends of polyethylene produced at 0 °C decrease whereas xNi increases indicating a good compatibility between phases of the polyethylene gotten with the two catalysts. The melting temperature for the blends of polyethylene showed be depend on the order according to which catalysts have been supported on the MAO-modified silica. The initial immobilization of 1 on the support (2/1/S2) product of polymers with a melting temperature (Tm) lower to the one of the polymer gotten when the titanium has been supported inicially (1/2/S2). The observation of polyethylenes gotten with the two systems (2/1/S2 and 1/2/S2) by scanning electron microscopy (SEM) showed the spherical polymer formation showing that the spherical morphology of the support to been reproduced. Are described the synthesis, the characterization and the catalytic properties for the oligomerization of the ethylene of four organometallics compounds of CrIII with ligands ([bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine] chromium (III) chloride (3a), [bis[2-(3,5- dimethyl-l-pyrazolyl)ethyl]benzylamine] chromium (III) chloride (3b), [bis[2-(3,5-dimethyl-lpyrazolyl) ethyl]ether] chromiun(III)chloride (3c), [bis[2-(3-phenyl-lpyrazolyl) ethyl]ether]chromiun(III)chloride (3d)). In relation of the oligomerization, at exception made of the compounds 3a, all complex of the chromium showed be active after activation with MAO and the TOF gotten have one effect differentiated to those formed with CrCl3(thf)3. The coordination of a tridentate ligand on the metallic center doesn't provoke any considerable changes on the formation of the C4 and C6, but the amount of C8 are decrease and the C10 and C12+ have increased. The Polymers produced by the catalyst 3a to 3 and 20 bar of ethylene have, according to analyses by DSC, the temperatures of fusion of 133,8 and 136ºC respectively. It indicates that in the two cases the production of high density polyethylene. The molar mass, gotten by GPC, is 46647 g/mols with MwD = 2,4 (3 bar). The system 3c/MAO showed values of TOF, activity and selectivity to different α-olefins according to the pressure of ethylene uses. Himself that shown a big sensibility to the concentration of ethylene solubilized.

Microeletrodos: II. Caracterização eletroquímica

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

Estudo do comportamento térmico e eletroquímico do sistema 'PT 'RH' 15%- 'HG/CU'

Pós-graduação em Química - IQ

Structured carbons as supports for hydrogenation hybrid catalysts prepared by the immobilization of a Rh diamine complex

A CNF-monolith sample (carbon nanofibres grown on a ceramic monolith), and a granular carbon xerogel have been used as supports for hybrid catalysts where the active species is an Rh diamine complex. The advantages of these supports are their open porous structure and their morphology, which make catalyst handling easier and avoid difficult separation processes. The obtained catalysts are noticeably more active than the homogeneous Rh complex and are stable against leaching. At first use, partial reduction of the Rh complex takes place and nanometer-sized Rh particles develop, which increases the catalyst activity. Despite the open porous structure, mass transport limitations are present, especially in the case of the carbon xerogel based catalyst. Differences in internal mass transfer limitations are essentially due to the different diffusional path lengths.

Nanotechnology in food industry II: risk assessment and legislation

Currently, there is increasing use of nanomaterials in the food industry thanks to the many advantages offered and make the products that contain them more competitive in the market. Their physicochemical properties often differ from those of bulk materials, which require specialized risk assessment. This should cover the risks to the health of workers and consumers as well as possible environmental risks. The risk assessment methods must go updating due to more widespread use of nanomaterials, especially now that are making their way down to consumer products. Today there is no specific legislation for nanomaterials, but there are several european dispositions and regulations that include them. This review gives an overview of the risk assessment and the existing current legislation regarding the use of nanotechnology in the food industry.

Correlacion entre hemoglobina glicosilada con hallazgos sintax score ii en pacientes con sospecha clínica de enfermedad coronaria, hospitalizados en la unidad coronaria del hospital San José centro en enero a septiembre del año 2015

Se realiza un estudio de corte transversal en el periodo de enero a septiembre del año 2016 en la unidad coronaria del Hospital San José Centro de la Ciudad de Bogotá; en pacientes con sospecha de enfermedad coronaria (Síndrome coronario agudo y angina estable) y antecedente de Diabetes Mellitus Tipo 2, se recolectaron 42 pacientes con los criterios de inclusión a quienes se realizó angiografía coronaria como parte del protocolo de estudio y manejo de la unidad, el objetivo primario fue demostrar la posible correlación entre niveles de hemoglobina glicosilada y la escala de severidad SYNTAX Score I y II de enfermedad coronaria, como objetivos secundarios; caracterizar las variables sociodemográficas, comorbilidades y posible relación con el tipo de presentación de enfermedad coronaria. Como hallazgos relevantes no se encontró correlación importante ni significativa entre niveles de hemoglobina glicosilada y la escala Syntax score II ni Syntax score I, a pesar de que la mayoría de pacientes mostraban mal control crónico de su diabetes mellitus tipo 2, con niveles mayores > 7%, como hallazgo positivo se encontro asociación estadísticamente significativa con niveles de LDL y las diferentes formas de presentación de enfermedad coronaria, a mayor niveles de LDL mayor probabilidad de IAM e IAM con elevación del segmento ST. Se considera que con estudios multicentricos en diferentes ciudades y unidades de cuidado cardiovascular con diferentes niveles de riesgo, se podría demostrar la posible correlación entre niveles de hemoglobina glicosilada y los grados de severidad de enfermedad coronaria representados por las escalas Syntax score I y II.