Search results for "Gradation"
showing 10 items of 1275 documents
Anaerobic biodegradation of solvents from the packaging industry: study and enhancement
2017
Con el desarrollo de la política ambiental de la Unión Europea, la calidad del aire en Europa ha mejorado considerablemente. No obstante, la contaminación atmosférica continúa siendo importante lo que hace necesario el desarrollo continuo de soluciones tecnológicas de depuración del aire para mitigar los problemas de calidad ambiental. Con objeto de preservar el medio ambiente y evitar problemas de salud pública, las emisiones industriales de disolventes están estrictamente reguladas por la normativa vigente en Europa, en el marco de la Directiva Europea de Emisiones Industriales (2010/75/EU). La industria del envase y embalaje es uno de los sectores más importantes en cuanto al uso de diso…
Urbanization and forest degradation in east Africa - a case study around Dar es Salaam, Tanzania
2016
In this paper we examine the impact of the growing urbanization of Dar es Salaam, Tanzania, on the forest areas around the city. Since 1990 the city has seen an annual population growth rate of over 4%. We document the expansion of the city over the last 30 using the Global Human Settlement Layers, derived from the global Landsat archive. At the same time we show the depletion, of the surrounding forests that has occurred to meet the growing demand for agricultural land, fuel wood and construction material over the same period. The impact on these forests as a result of the demand from an expanding urban conglomeration is higher than would be expected from a dispersed population increase. T…
Physical and chemical changes in minimally processed green asparagus during cold-storage
2007
The purpose of this research is to study effects of an innovative packaging method on the shelf-life of minimally processed green asparagus. The physical-chemical parameters analyzed (weight loss, colour, texture, chlorophyll and citric acid), and monitored by untrained panellists during the cold storage period at 6 degrees C, showed that pairing of a semi-permeable film with an adsorbent material and immersion in ascorbic acid solution were able to extend the shelf-life of green asparagus. Also, on the basis of the results obtained, a study of the chlorophyll and toughness degradation kinetics of green asparagus was conducted during cold storage. These data showed the toughening of asparag…
The impact of high-temperature, short-time thermal treatment on texture and weight loss of green asparagus
1997
The kinetics of the degradation of texture and loss of weight of green asparagus heated to between 100 and 130 °C was studied. The texture of the asparagus was evaluated with two types of cells fitted to a universal texturometer: one cell measured resistance to cutting with a wire and the other was a Kramer cell. The two methods enabled distinction between the different thermal treatments, although the Kramer cell gave information about the behaviour of parts of the spear further away from the tip. The thermally induced degradation of the texture and loss of weight followed first-order kinetics. With respect to the texture, the parameters obtained with the wire cell 2.5, 5 and 7.5 cm from t…
PHB-based films as matrices for pesticides
2002
Abstract The effects of pesticides incorporated into PHB-based polymeric matrices on the biodegradability of films and antifungal efficiency of immobilised pesticides to Botrytis cinerea was studied. The mass loss of tested PHB-based films for 2 weeks was 40–50% and after 4 weeks 92–96% of the initial mass. The fungicides Ronilan and Sumilex immobilised into the polymeric matrices did not depress the film degradation rate. PHB-based films caused changes in the soil microorganism association. Fungicides immobilised in PHB-based matrices decreased the count of the phytopathogenic fungus B. cinerea.
Real time analysis of Escherichia coli biofilms using calorimetry
2008
Abstract Microbial communities grow more stably when they are associated to surfaces or organized in aggregates. This advantage of biofilms is technically exploited for the degradation of xenobiotics or in biocatalysis, where the fixed biomass has the added advantage of easier separation of excreted products. Whereas the biothermodynamic analysis of growth and product formation of suspended cells is developing fast, there are only few reports on the calorimetric analysis and biothermodynamic interpretation of biofilm evolution. Experiments illustrate the ability of calorimetry to monitor the physiological state of biofilms in real time. Sessile cells of Escherichia coli DH5α DSM 6897 were s…
Dehydrochlorination of Hexachlorocyclohexanes Catalyzed by the LinA Dehydrohalogenase. A QM/MM Study
2015
The elucidation of the catalytic role of LinA dehydrohalogenase in the degradation processes of hexachlorocyclohexane (HCH) isomers is extremely important to further studies on the bioremediation of HCH polluted areas. Herein, QM/MM free energy simulations are employed to provide the details of the dehydrochlorination reaction of two HCH isomers (γ and β). In particular, the role of the protonation state of one of the catalytic residues-His73-is explored. Based on our calculations, two distinct minimum free energy pathways (concerted and stepwise) were found for γ-HCH and β-HCH. The choice of the reaction channel for the dehydrochlorination reactions of γ- and β-HCH was shown to depend on t…
Synthetic/ECM-inspired hybrid platform for hollow microcarriers with ROS-triggered nanoporation hallmarks
2017
Reactive oxygen species (ROS) are key pathological signals expressed in inflammatory diseases such as cancer, ischemic conditions and atherosclerosis. An ideal drug delivery system should not only be responsive to these signals but also should not elicit an unfavourable host response. This study presents an innovative platform for drug delivery where a natural/synthetic composite system composed of collagen type I and a synthesized polythioether, ensures a dual stimuli-responsive behaviour. Collagen type I is an extracellular matrix constituent protein, responsive to matrix metalloproteinases (MMP) cleavage per se. Polythioethers are stable synthetic polymers characterized by the presence o…
Cloning of an alkane hydroxylase system in a long chain n-alkane- degrader Gordonia sp.
2008
Five Gram-positive GC rich n-alkane degraders were isolated from a long-term accidentally contaminated beach in Sicily and identified as one Nocardia, two Rhodococcus and two Gordonia strains (Quatrini et al., 2008 J. Appl. Microbiol. 104:251-9). All the isolates were able to grow on long and very long chain n-alkanes up to C36. Diverging alkane-hydroxylase encoding genes (alkB) were detected by PCR using degenerated primers in all the strains. Multiple sequences were obtained from the Nocardia strain while only one alkB gene was detected in Rhodococcus and Gordonia. The aim of this work is to genetically characterize the alk cluster in one of the two Gordonia strains called SoCg. Pulsed Fi…
BIODEGRADACJA ZWIĄZKÓW FOSFONOWYCH PRZEZ GRZYBY
2020
Phosphonates are the group of organophosphorus compounds, which are characterized by the presence of covalent bond(s) between carbon and phosphorus atom in their structure. Both; the natural and synthetic phosphonic compounds, are encountered in various ecosystems, however because of their wide range of applications, the latter ones are considerably more frequently discussed. Regarding the broad spectrum of biological activity, capability to chelate metal cations and environmental stability of direct carbon to phosphorus bond under physiological conditions, phosphonic compounds found a variety of applications e.g. as pesticides, drugs, anticorrosive agents, additives to surfactants and flam…