Search results for "TRANSFORMATION"
showing 10 items of 1634 documents
Unsaturated fatty acid bioconversion by apple pomace enzyme system. Factors influencing the production of aroma compounds
1996
Productions of volatile compounds (hexanal and 2,4-decadienal) obtained from polyunsaturated fatty acids by action of specific apple pomace enzyme system were quantitatively improved by increasing substrate and enzyme concentrations in the reaction medium. The importance of an exogenous supply of oxygen during bioconversion was also shown. Some physico-chemical factors involved in the pomace enzyme system expression were screened. A temperature of 25°C was favourable to the bioconversion. The control of alkaline or acidic conditions in the reaction medium may orientate the reaction preferentially to the production of one or other aldehyde.
Infiuence of Foreign Compounds on Formation and Disposition of Reactive Metabolites
2008
Many toxic compounds are unreactive and need biotransformation in order to exert their toxic effects. Several enzymes control the formation or disposition of reactive metabolites. Especially well studied is the group of enzymes responsible for the control of reactive epoxides. Such epoxides may bind spontaneously to DNA, RNA and protein. These alterations of critical cellular macromolecules may disturb the normal biochemistry of the cell and lead to cytotoxic, allergenic, mutagenic and carcinogenic effects. Whether these effects will be manifested depends on the chemical reactivity as well as on other properties (geometry, lipophilicity) of the epoxide in question. Enzymes controlling the c…
Loss of Hyperconjugative Effects Drives Hydride Transfer during Dihydrofolate Reductase Catalysis
2019
Hydride transfer is widespread in nature and has an essential role in applied research. However, the mechanisms of how this transformation occurs in living organisms remain a matter of vigorous debate. Here, we examined dihydrofolate reductase (DHFR), an enzyme that catalyzes hydride from C4′ of NADPH to C6 of 7,8-dihydrofolate (H2F). Despite many investigations of the mechanism of this reaction, the contribution of polarization of the π-bond of H2F in driving hydride transfer remains unclear. H2F was stereospecifically labeled with deuterium β to the reacting center, and β-deuterium kinetic isotope effects were measured. Our experimental results combined with analysis derived from QM/MM si…
Comparison between the Kummer's transformation and Ewald method for the evaluation of the parallel plate Green's functions
2006
In this paper, we present a convergence and efficiency study of two different acceleration techniques for the evaluation of the parallel plate Green's functions. The first technique is based on the extraction of the asymptotic terms of the spectral representation of the parallel plate Green's functions by applying the Kummer's transformation. The second technique is a straightforward reformulation of the 2-D Green's functions for 1-D periodic structures to the parallel plate case. The PPW Green's functions calculated by the two methods have been successfully applied to the analysis of a practical inductive microwave filter containing metallic and dielectric posts. The filter analysis techni…
ChemInform Abstract: Transformation of Artemisin Into Artapshin and 8α-Hydroxy-11β,13-Dihydrobalchanin.
1987
Abstract Partial syntheses of the sesquiterpene lactones artapshin ( 1 ) and 8α-hydroxy-11β, 13-dihydrobalchanin ( 2 ) from artemisin ( 3 ) are described.
VI JORNADAS ARTE Y CIUDAD (III Encuentros Internacionales) Madrid, 1, 2 y 3 de Abril de 2014 Facultad de Ciencias de la Información Universidad Compl…
2014
In the conquest of Valencia in 1238 and its subsequent Christianization we find the genesis of the convent city. Over the centuries the dominant presence of convents and monasteries determined various aspects of the city, urban development being one of them. However, the influence and power that these monasteries exercised diminished gradually with the reduction in the number of their members and foundations. The point of no return comes with the nineteenth century when the successive confiscations and the consolidation of the bourgeoisie mean its fading. This study aims to make an approach to the role that the destruction of convents and monasteries played in the urban development and prog…
Living in future cities: from overbuilding to ecological transition
2022
In contemporary cities the levels of livability and urban quality are less and less optimal. There are various causes: climate and demographic changes, reduction of natural resources, health risks, excessive consumption of soil, increased pollution, impoverishment of populations, lack of employment, transformation of urban space, etc. Evolving cities, increasingly vulnerable, characterized by insecurity, uncertainty and unpredictability, the result of mistakes made in the past. In this context, in planning future scenarios it is necessary to re-examine the governance, the strategies of urban expansion and transformation through new approaches capable of declining innovative concepts such as…
What is (not) the point of just transition in food systems?
2022
Food systems are confronted with a low-carbon transition challenge. The need for significant emission reductions in industrial food systems implies significant systemic transformations in food production, processing, and consumption. The wide-reaching impacts of such transformations have evoked public discussion and academic research on just transition in food systems. The undisputable legitimacy of the idea of just transition makes it an attractive concept for all food system actors who might be affected by low-carbon transition policies in direct and indirect ways. Some of the claims that are being made are warranted claims for justice, some merely defend the achieved privileges and benef…
Solubility-Driven Isolation of a Metastable Nonagold Cluster with Body-Centered Cubic Structure.
2020
The conventional synthetic methodology of atomically precise gold nanoclusters using reduction in solutions offers only thermodynamically most stable nanoclusters. We report herein a solubility‐driven isolation strategy to access the synthesis of a metastable gold cluster. The cluster, with the composition of [Au 9 (PPh 3 ) 8 ] + ( 1 ), displays an unusual, nearly perfect body‐centered‐cubic (bcc) structure. As revealed by ESI‐MS and UV/Vis measurement, the cluster is metastable in solution and converts to the well‐known [Au 11 (PPh 3 ) 8 Cl 2 ] + ( 2 ) within just 90 min. DFT calculations revealed that while both 1 and 2 are eight‐electron superatoms, there is a driving force to convert 1 …
The Labour Market and the Digital Revolution: Focus on Some Effects, Legislative Implications and the Role of Collective Bargaining
2021
In the last years, in Italy as in other European countries, external influences have been crucial throughout the ongoing transformation of labour law, which has undergone a phase of epochal change regarding all of the ‘components of its historical model stemming from a deregulation process as well as a great change in the scientific paradigm. The subject’s sensitivity to the external influences has resulted in a transformation, which has inevitably also affected the system of industrial relations, ultimately challenging the role and the dynamics of collective bargaining. The work paradigm of the twentieth century appeared inadequate and insufficient to face all the challenges that had been …