Université catholique de Louvain

About: Université catholique de Louvain is a education organization based out in Louvain-la-Neuve, Belgium. It is known for research contribution in the topics: Population & Catalysis. The organization has 25319 authors who have published 57360 publications receiving 2172080 citations. The organization is also known as: University of Louvain & UCLouvain.

Soil Spectroscopy: An Alternative to Wet Chemistry for Soil Monitoring

Abstract: The soil science community is facing a growing demand of regional, continental, and worldwide databases in order to monitor the status of the soil. However, the availability of such data is very scarce. Cost-effective tools to measure soil properties for large areas (e.g., Europe) are required. Soil spectroscopy has shown to be a fast, cost-effective, environmental-friendly, nondestructive, reproducible, and repeatable analytical technique. The main aim of this paper is to describe the state of the art of soil spectroscopy as well as its potential to facilitating soil monitoring. The factors constraining the application of soil spectroscopy as an alternative to traditional laboratory analyses, together with the limits of the technique, are addressed. The paper also highlights that the widespread use of spectroscopy to monitor the status of the soil should be encouraged by (1) the creation of a standard for the collection of laboratory soil spectra, to promote the sharing of spectral libraries, and (2) the scanning of existing soil archives, reducing the need for costly sampling campaigns. Finally, routine soil analysis using soil spectroscopy would be beneficial for the end users by a reduction in analytical costs, and an increased comparability of results between laboratories. This ambitious project will materialize only through (1) the establishment of local and regional partnerships among existent institutions able to generate the necessary technical competence, and (2) the support of international organizations. The Food and Agriculture Organization (FAO) of United Nations and the Joint Research Centre of the European Commission are well placed to promote the use of laboratory and field spectrometers for monitoring the state of soils.

Lack of cadherins Celsr2 and Celsr3 impairs ependymal ciliogenesis, leading to fatal hydrocephalus

Abstract: Ependymal cells form the epithelial lining of cerebral ventricles. Their apical surface is covered by cilia that beat in a coordinated fashion to facilitate circulation of the cerebrospinal fluid (CSF). The genetic factors that govern the development and function of ependymal cilia remain poorly understood. We found that the planar cell polarity cadherins Celsr2 and Celsr3 control these processes. In Celsr2-deficient mice, the development and planar organization of ependymal cilia are compromised, leading to defective CSF dynamics and hydrocephalus. In Celsr2 and Celsr3 double mutant ependyma, ciliogenesis is markedly impaired, resulting in lethal hydrocephalus. The membrane distribution of Vangl2 and Fzd3, two key planar cell polarity proteins, was disturbed in Celsr2 mutants, and even more so in Celsr2 and Celsr3 double mutants. Our findings suggest that planar cell polarity signaling is involved in ependymal cilia development and in the pathophysiology of hydrocephalus, with possible implications in other ciliopathies.

Purification and preliminary characterization of the extracellular lipase of Bacillus subtilis 168, an extremely basic pH‐tolerant enzyme

Abstract: The extracellular lipase of Bacillus subtilis 168 was purified from the growth medium of an overproducing strain by ammonium sulfate precipitation followed by phenyl-Sepharose and hydroxyapatite column chromatography. The purified lipase had a strong tendency to aggregate. It exhibited a molecular mass of 19,000 Da by SDS-PAGE and a pI of 9.9 by chromatofocusing. The enzyme showed maximum stability at pH 12 and maximum activity at pH 10. The lipase was active toward p-nitrophenyl esters and triacylglycerides with a marked preference for esters with C8 acyl groups. Using trioleyl glycerol as substrate, the enzyme preferentially cleaved the 1(3)-position ester bond. No interfacial activation effect was observed with triacetyl glycerol as substrate.

Study of the Hydrodeoxygenation of Carbonyl, Carboxylic and Guaiacyl Groups Over Sulfided Como/gamma-al2o3 and Nimo/gamma-al2o3 Catalysts .1. Catalytic Reaction Schemes

Abstract: The elimination of specific oxygenated groups of biomass-derived pyrolysis oils (bio-oils) is necessary for improving their stability. These are mainly unsaturated groups like alkene, carbonyl and carboxylic functions, as well as guaiacyl groups. For practical applications, it is desirable that the reactions are performed selectively in order to avoid excessive hydrogen consumption. The reactions must be done at relatively low temperature in order to limit competitive thermal condensation reactions. In this study, model oxygenated compounds were used, namely 4-methylacetophenone, diethyldecanedioate and guaiacol. They were tested simultaneously in one reaction test in the presence of sulfided cobalt-molybdenum and nickel-molybdenum supported on gamma-alumina catalysts in a batch system. Their reactivity and conversion scheme were determined. The ketonic group is easily and selectively hydrogenated into a methylene group at temperatures higher than 200 degrees C. Carboxylic groups are also hydrogenated to methyl groups, but a parallel decarboxylation occurs at comparable rates. A temperature around 300 degrees C is required for the conversion of carboxylic groups as well as for the conversion of the guaiacyl groups. The main reaction scheme of guaiacol is its transformation in hydroxyphenol which is subsequently converted to phenol. But in batch reactor conditions, guaiacol gives a high proportion of heavy products. CoMo and NiMo catalysts have comparable activities and selectivities. However, the NiMo catalyst has a higher decarboxylating activity than CoMo and also leads to a higher proportion of heavy products during the conversion of guaiacol.