Ethylene oligomerization promoted by chromium complexes bearing pyrrolide–imine–amine/ether tridentate ligands

International audienceChromium(iii) complexes [CrCl2(L)(THF)] based on monoanionic tridentate ligands [, L = {2-(C4H3N-2'-CH[double bond, length as m-dash]N)C2H4NHPh}; , L = {5-tert-butyl-2-(C4H2N-2'-CH[double bond, length as m-dash]N)C2H3NHPh}; , L = {2-(C4H3N-2'-CH[double bond, length as m-dash]N)C2H4OPh}] have been prepared. Complexes and were converted into the monomeric acetonitrile adducts [CrCl2(L)(NCMe)] [, L = {2-(C4H3N-2'-CH[double bond, length as m-dash]N)C2H4NHPh}; , L = {5-tert-butyl-2-(C4H2N-2'-CH[double bond, length as m-dash]N)C2H3NHPh}] by reaction with acetonitrile at room temperature. All Cr complexes were characterized by IR spectroscopy, elemental analysis, magnetochemistry for , and by X-ray crystallography for and . Upon activation with methylaluminoxane (MAO), chromium precatalysts and showed good activity in ethylene oligomerization (TOF = 47.0-57.0 × 10(3) (mol ethylene)(mol Cr)(-1) h(-1) at 80 °C), producing mostly oligomers (93.0-95.6 wt% of total products). On the other hand, under identical oligomerization conditions, /MAO behaved as a polymerization catalyst generating predominantly polyethylene (73.0 wt%). However, the catalytic behavior of the precatalyst can be adjusted by varying the MAO-to-Cr ratio. Thus, the use of 500 equiv. causes a dramatic shift from polymerization to ethylene oligomerization, eventually producing mainly lighter α-olefin fractions [α-C4 (68.7 wt%) and α-C6 (19.2 wt%)]. A further increase in the amount of MAO (1000 equiv.) leads to a more balanced distribution of oligomers, with a drastic decrease in the α-C4 and increase in the α-C8 fractions

Development of light cream cheese with the addition of Chia seeds (Salvia hispanica L.)/ Desenvolvimento de queijo cremoso leve com a adição de sementes de Chia (Salvia hispanica L.)

Currently, due to the increasing incidence of heart disease and obesity worldwide, the market demand requires foods with lower rates of lipids. The dietary fiber allows the reduction of carbohydrate and/or fat in a series of processed foods. Thus, soluble fibers, such as fibers of chia seed (Salvia hispanica L), may be an ingredient in the processing of cream cheese differentiated. The aim of this study was to develop cream cheese with low fat content and adding chia seeds. The products developed, have been evaluated by untrained volunteers. Sensory analysis indicated good acceptability of the samples with respect to all parameters. The results suggest that the preparation of cream cheese without adding fat and reduced fat were not well sensory acceptance. However, the cream cheese made with chia seed without reducing fat or partial replacement (50%) of fat obtained excellent acceptance by the evaluators. We therefore conclude that chia seeds were not able to replace the sensory properties of fat in fat-free cream cheese prepared. However, the addition of chia seed as a source of fiber was well accepted both in whole and reduced fat content cream cheese

TRATAMENTO EM MASSA COMO ESTRATÉGIA DE CONTROLE DE PARASITAS INTESTINAIS NÃO REDUZ A PREVALÊNCIA DE INFECÇÕES EM ESCOLARES INDÍGENAS GUARANIS NO BRASIL

The high frequency of intestinal parasites is favored by environmental and socio-cultural conditions of indigenous populations, and is still a neglected public health problem. Mass administration of broad-spectrum drugs aims to reduce the prevalence and intensity of the infections. The prevalence of intestinal parasites in school-children in an indigenous Guarani village was evaluated before and after the mass treatment of the population with albendazole. In the first phase of collection of stool samples, 81.4% of them were positive for enteroparasites and in the second phase, after two doses of antiparasitic medication, 87.5% were positive. Although the prevalence of infections by some helminths has reduced after treatment, many parasites remained frequent in the studied population, showing a change in the epidemiological profile in the distribution of these diseases in the population. The prevalence of intestinal parasites in indigenous schoolchildren proved to be high even after mass treatment with albendazole.A alta frequência de parasitoses intestinais é favorecida por condições ambientais e socioculturais das populações indígenas, sendo ainda um problema de saúde pública negligenciado. A administração em massa de medicamentos de amplo espectro busca reduzir o número e a intensidade das infecções. Avaliou-se a prevalência de parasitoses intestinais em escolares de uma aldeia indígena Guarani, antes e após o tratamento em massa da população com o albendazol. Na primeira fase de coleta das amostras de fezes, 81,4% delas apresentaram-se positivas para enteroparasitos e na segunda fase, após duas doses de antiparasitário, 87,5% apresentaram-se positivas. Embora a prevalência de infecções por alguns helmintos tenha reduzido após o tratamento, muitos parasitos continuaram frequentes na população estudada, mostrando uma mudança no perfil epidemiológico na distribuição dessas doenças na população. A prevalência de enteroparasitoses nos escolares indígenas mostrou-se elevada mesmo após o tratamento em massa com albendazol

G1 phase arrest by the phosphatidylinositol 3-kinase inhibitor LY 294002 is correlated to up-regulation of p27Kip1 and inhibition of G1 CDKs in choroidal melanoma cells

AbstractWe have investigated the effect of the flavonoid derivative LY 294002, a potent and selective phosphatidylinositol 3-kinase inhibitor, on cell cycle progression in human choroidal melanoma cells. We demonstrate that LY 294002 induces a specific G1 block in asynchronously growing cells leading to an almost complete inhibition of cell proliferation after three days of treatment. When melanoma cells are released from a nocodazole-induced G2/M block, LY 294002 is shown to delay and greatly restrain the G1/S transition. The inhibitor is able to exert its action as long as it is added during the G1 progression and before the cells enter in S phase. We report that the LY 294002-induced G1 arrest is closely correlated to inhibition of CDK4 and CDK2 activities leading to the impairment of pRb phosphorylation which normally occurs during G1 progression. While the inhibition of CDK4 may be attributed at least in part to the decline in CDK4 protein level, CDK2 activity reduction is rather due to the up-regulation of the CDK inhibitor p27Kip1 and to its increased association to CDK2

Comparação entre o comportamento dos tecidos ósseos após a instalação imediata de implantes com função imediata em áreas estéticas instalados ou não por meio de cirurgia guiada: Série de casos

Objetivo: Identificar a taxa de sobrevivência e comparar a resposta óssea peri-implantar em implantes imediatos instalados ou não por meio de cirurgia guiada. Materiais e Métodos: Foram selecionados 12 pacientes, os quais possuíam 12 implantes imediatos realizados sem retalho em região anterior da maxila há, em média, 2 anos. Estes foram divididos em dois grupos: Grupo I de implantes instalados em cirurgia à mão livre e provisionalização imediata e Grupo II de implantes instalados utilizando o Neodent Guided Surgery (NGS) e submetidos a provisionalização imediata com a utilização de TiBase com pilar de zircônia. Imagens radiográficas foram obtidas em 2 tempos: Imediatamente após a instalação dos implantes (T1), e entre 12 e 59 meses (Média = 24,4 meses) após a instalação dos implantes(T2). O nível ósseo foi avaliado em duas diferentes posições, no ponto onde há o primeiro contato do osso com a face lateral do implante (Alt 1) e na crista óssea (Alt 2), nas faces mesial e distal. Resultados: Observou-se redução na altura óssea em todas as variáveis, porém com significância estatística apenas no grupo I, medida Alt 1 face distal e Alt 2 face mesial. Conclusão: Em ambos os grupos a taxa de sobrevivência foi de 100%, e a redução em altura óssea observada está de acordo com os dados da literatura

A Demanda Bioquímica de Oxigênio (DBO) e possíveis fatores de influência nos processos em águas superficiais do Rio São Francisco Verdadeiro – Paraná

Estudar e conhecer de forma sucinta as formas como diferentes parâmetros podem influenciar uma variável ambiental é de extrema importância para a compreensão dos processos existentes meio aquático. O presente trabalho busca compreender e relacionar variáveis que, de alguma forma, influenciem as concentrações da DBO no ambiente. Foram realizadas análises de Sólidos Totais Dissolvidos (STD), Temperatura (°C) e Clorofila-a no Rio São Francisco Verdadeiro, buscando correlacioná-las com a DBO (Correlação de Pearson). A temperatura não apresentou correlações significativas ao processo e, demonstrou-se um padrão de aumento da DBO com o acréscimo das concentrações de STD (R²=0,894) e uma relação inversamente proporcional entre a Clorofila-a e a DBO (R²= -0,854). Os valores de Clorofila-a (mg/L), são inversamente proporcionais aos da Demanda Bioquímica de Oxigênio, indicando a presença de matéria orgânica não degradada no meio. Dessa forma, ambientes com elevadas concentrações de DBO podem vir à limitar o estabelecimento da nova comunidade fitoplânctonica. Além disso, as concentrações elevadas de Sólidos Totais Dissolvidos indicam a possível presença de fontes difusas e pontuais de poluição na medida em que o rio segue seu curso natural, correlacionadas com a demanda de oxigênio necessária à degradação destes compostos

Prediction of survival with second-line therapy in biliary tract cancer: Actualisation of the AGEO CT2BIL cohort and European multicentre validations

BACKGROUND: The benefit of second-line chemotherapy (L2) over standard first-line (L1) gemcitabine plus cisplatin (GEMCIS) or oxaliplatin (GEMOX) chemotherapy in advanced biliary tract cancer (aBTC) is unclear. Our aim was to identify and validate prognostic factors for overall survival (OS) with L2 in aBTC to guide clinical decisions in this setting. METHODS: We performed a retrospective analysis of four prospective patient cohorts: a development cohort (28 French centres) and three validation cohorts from Italy, UK and France. All consecutive patients with aBTC receiving L2 after GEMCIS/GEMOX L1 between 2003 and 2016 were included. The association of clinicobiological data with OS was investigated in univariate and multivariate Cox analyses. A simple score was derived from the multivariate model. RESULTS: The development cohort included 405 patients treated with L1 GEMOX (91%) or GEMCIS. Of them, 55.3% were men, and median age was 64.8 years. Prior surgical resection was observed in 26.7%, and 94.8% had metastatic disease. Performance status (PS) was 0, 1 and 2 in 17.8%, 52.4% and 29.7%, respectively. Among 22 clinical parameters, eight were associated with OS in univariate analysis. In multivariate analysis, four were independent prognostic factors (p < 0.05): PS, reason for L1 discontinuation, prior resection of primary tumour and peritoneal carcinomatosis. The model had the Harrell's concordance index of 0.655, a good calibration and was validated in the three external cohorts (N = 392). CONCLUSION: We validated previously reported predictive factors of OS with L2 and identified peritoneal carcinomatosis as a new pejorative factor in nearly 800 patients. Our model and score may be useful in daily practice and for future clinical trial design