54 research outputs found
Greener Method to Obtain a Key Intermediate of Vitamin E over Cu-ZSM-5
The catalytic oxidation of 2,3,5-trimethylphenol was performed over transition metals modified ZSM-5 zeolites employing hydrogen peroxide as oxidant under mild reaction conditions. Catalysts samples were characterized by several techniques (XRD, FTIR, BET, AA) and cristallinity and orthorhombic symmetry were confirmed for all of them. Best catalytic results were obtained for Cu-ZSM-5 sample, so further activity studies were done over this material. 2,3,5-trimethyl-1,4-benzoquinone was obtained as the main product of the selective oxidation. Reaction parameters (nature of the solvent, hydrogen peroxide concentration, reaction time, catalyst mass, substrate initial concentration and reaction temperature) were evaluated to reach the optimum reaction conditions. According to the obtained results, an apparent activation energy of 52.33 kJ/mol was calculated.Fil: Saux, Clara. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Renzini, Maria Soledad. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Gómez, Silvina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; ArgentinaFil: Pierella, Liliana Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina. Universidad Tecnologica Nacional. Facultad Regional Cordoba; Argentin
Bio-Geo-Graphy: Landscape, Dwelling, and the Political Ecology of Human-Elephant Relations
The relation between the bio and the geo has been amongst geography's most enduring concerns. This paper contributes to ongoing attempts in human geography to politicise the dynamics and distribution of life. Drawing upon postcolonial environmental history, animal ecology, and more-than-human geography, the paper examines how humans and elephants cohabit with and against the grain of cartographic design. Through fieldwork in northeast India, it develops a ‘dwelt political ecology’ that reanimates landscape as a dwelt achievement whilst remaining sensitive to postcolonial histories and subaltern concerns. The paper conceptualises and deploys a methodology of ‘tracking’ through which archival material, elephant ecology, and voices of the marginalised can be integrated and mapped. It concludes by discussing the implications of this work for fostering new conversations between more-than-human geography and subaltern political ecology
A Systematic Review of the Frequency of Neurocyticercosis with a Focus on People with Epilepsy
Neurocysticercosis (NCC) is a parasitic infection of the brain caused by the tapeworm Taenia solium, which infects humans and pigs. There have been increasing case reports and epidemiological studies on this disease, but its global frequency has never been determined, partly due to the fact that blood tests are not very good for the diagnosis of NCC. We present here a systematic review of the literature on the frequency of NCC diagnosed with neuroimaging worldwide. Overall, 565 articles were retrieved and 290 (51%) selected for further review. Of those, only 26 had information valid enough to estimate the frequency of NCC in various populations. Only one study estimated the prevalence of NCC in the general population. The most striking finding was that the proportion of NCC among persons with epilepsy was very consistent and estimated at 29.6% (95%CI: 23.5%–36.1%) from 12 studies conducted in Latin America, Sub-Saharan Africa and Southeast Asia. A reinforcement of the suggested universal guidelines for the diagnostic process, declaring NCC an international reportable disease and standardizing procedures for data collection could improve our understanding of the frequency of NCC worldwide and hence its global burden
Benign external hydrocephalus: a review, with emphasis on management
Benign external hydrocephalus in infants, characterized by macrocephaly and typical neuroimaging findings, is considered as a self-limiting condition and is therefore rarely treated. This review concerns all aspects of this condition: etiology, neuroimaging, symptoms and clinical findings, treatment, and outcome, with emphasis on management. The review is based on a systematic search in the Pubmed and Web of Science databases. The search covered various forms of hydrocephalus, extracerebral fluid, and macrocephaly. Studies reporting small children with idiopathic external hydrocephalus were included, mostly focusing on the studies reporting a long-term outcome. A total of 147 studies are included, the majority however with a limited methodological quality. Several theories regarding pathophysiology and various symptoms, signs, and clinical findings underscore the heterogeneity of the condition. Neuroimaging is important in the differentiation between external hydrocephalus and similar conditions. A transient delay of psychomotor development is commonly seen during childhood. A long-term outcome is scarcely reported, and the results are varying. Although most children with external hydrocephalus seem to do well both initially and in the long term, a substantial number of patients show temporary or permanent psychomotor delay. To verify that this truly is a benign condition, we suggest that future research on external hydrocephalus should focus on the long-term effects of surgical treatment as opposed to conservative management
Thermoelectric switch from anilinic compounds
521-524Copper(II) ion can be embedded in the aggregates
formed by anilinic compounds, such as 2,4-dimethoxyaniline, 2-aminophenol, 4-aminophenol,
protonated polyaniline, through a reaction of catalytic amounts of copper
complexes such as cis-bis (glycinato)copper(II)
monohydrate and copper(II) acetate in the presence of hydrogen peroxide. These
aggregates have the property of an irreversible thermoelectric switch.</span
Not Available
Not AvailableNational Highway may have damaging effect on soil chemical properties. In this study, a scale and assessment of selected chemical properties of tea growing soils with increasing sampling distance from National Highway have been documented. Top and sub soils from ten tea estates surrounding the National Highway of Dibrugrah and Tinsukia districts at the Upper Brahmaputra plain of India were analysed to understand the variation of the selected chemical properties influenced by National Highway. Significantly lower (p < 0.05) pHs and higher electrical conductivity were found in top soils than sub soils irrespective of sampling location from National Highway reflecting higher amount of soluble salt in top soils. Organic carbon (7.52–25.88 g kg−1), total nitrogen (0.70–2.47 g kg−1), available phosphorous (14.11–28.82 mg kg−1) and potassium (95.24–125.92 mg kg−1) were found significantly higher (p < 0.05) in top soils than sub soils irrespective of sampling locations. Total concentrations (g kg−1) of copper (0.012–0.034), iron (17.62–35.25), manganese (0.057–0.448) and zinc (0.039–0.097) in top soil were higher than the sub soil (copper: 0.012–0.029; iron: 15.57–31.15; manganese: 0.053–0.340 and zinc: 0.038–0.074). All the soils samples were found non-contaminated according to Indian standard. Application of generalized linear model revealed significant differences in metal content across the sampling distances from the National Highway. The novelty of this study is that tea growing soils in this region characterized by traffic-related build-up metals in top soils near to National Highway. Hierarchical cluster analysis and principal component analysis were applied to form homogenous groups of the studied parameters.Not Availabl
- …