Antioxidant activities and phenolic constituents of Cephalotaxus oliveri Mast. aerial parts

The present study was to analyze the antioxidant activity and the responsible chemical constituents in Cephalotaxus oliveri Mast. aerial parts. DPPH (2,2-diphenyl-1-picryl hydrazyl), ABTS [2,2’-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid)], reducing power and total phenolic content assays indicate that the methanol extract of the aerial parts is the most potent radical-scavenger and reducing agent with the highest level of phenolic content among the test extracts. The highly positive linear correlations implicate that the four assays have similar capacity to predict the antioxidant potential of the aerial parts and phenolic compounds present contribute significantly to DPPH and ABTS radical scavenging activity and reducing power of the extracts. The plant also displayed considerable superoxide anion radical scavenging activity. LC-MS/MS and GC-MS analyses resulted in the identification of 22 compounds in the methanol extract, among which are 15 phenolic compounds. The total amount of the phenolic compounds in the methanol extract determined by HPLC method was more than 5622.39 μg/g dry weight. The considerable antioxidant potential and a high content of phenolic antioxidants suggest that C. oliveri aerial parts are a potential source of natural antioxidants

Optimization of laccase production by Pycnoporus sanguineus in submerged liquid culture

The white-rot fungus Pycnoporus sanguineus produces laccase under a range of C/N ratios in submerged liquid culture. Enzyme production was increased 50 fold in the presence of 20 μM xylidine to a maximum of 1368 U L-1 in a high carbon low nitrogen medium. Slight repression of enzyme production was observed in high nitrogen culture medium. Other potential inducers were less effective (Tween 80, wood fibres) and reduced the stimulation observed by xylidine alone when included in the same culture medium. Veratryl alcohol failed to stimulate laccase production. Activity of the enzyme activity in crude culture nitrate was stable at temperatures of 35 C and below with a pH optimum of 3.0. The laccase of P. sanguineus was identified as a ca 65 kDa protein produced as multiple isoforms.published_or_final_versio

Thermolab: A Thermodynamics Laboratory for Nonlinear Transport Processes in Open Systems

We developed a numerical thermodynamics laboratory called “Thermolab” to study the effects of the thermodynamic behavior of nonideal solution models on reactive transport processes in open systems. The equations of the state of internally consistent thermodynamic data sets are implemented in MATLAB functions and form the basis for calculating Gibbs energy. A linear algebraic approach is used in Thermolab to compute Gibbs energy of mixing for multicomponent phases to study the impact of the nonideality of solution models on transport processes. The Gibbs energies are benchmarked with experimental data, phase diagrams, and other thermodynamic software. Constrained Gibbs minimization is exemplified with MATLAB codes and iterative refinement of composition of mixtures may be used to increase precision and accuracy. All needed transport variables such as densities, phase compositions, and chemical potentials are obtained from Gibbs energy of the stable phases after the minimization in Thermolab. We demonstrate the use of precomputed local equilibrium data obtained with Thermolab in reactive transport models. In reactive fluid flow the shape and the velocity of the reaction front vary depending on the nonlinearity of the partitioning of a component in fluid and solid. We argue that nonideality of solution models has to be taken into account and further explored in reactive transport models. Thermolab Gibbs energies can be used in Cahn-Hilliard models for nonlinear diffusion and phase growth. This presents a transient process toward equilibrium and avoids computational problems arising during precomputing of equilibrium data

Physical and chemical interaction in the interior of the Caledonian mountains of Norway

Four hundred million years ago, rocks that are found along the present day Norwegian coast were situated in the deep root underneath a huge mountain range. Through movements of the Earth’s crust that are caused by stresses in combination with erosion these rocks became exposed on the Earth’s surface, and it is therefore possible to study the physical and chemical processes that took place in the interior of the so called Caledonian mountain range in these rocks. The study of these processes presented in this dissertation has been evaluated by the adjudication committee as ‘novel and provocative’ and is of major importance for the progress in understanding the formation of mountain ranges. The physics and chemistry of the rock forming processes have been studied in detail in some very rare garnet peridotite and eclogite rocks that are found by the author in an outcrop along the Norwegian coast, northwest of Molde. The series of articles collected in this dissertation describes several discoveries including very small (0.001 mm) diamonds. Furthermore, it describes in detail the fluid and melt processes that took place at high pressure in the deep root of the mountain. The dissertation also presents an alternative model for the formation of the type of rocks described, which contrasts strongly with the presently accepted views, but that better explains the presented observations and measurements. The work presented in the dissertation was carried out at ‘Physics of Geological Processes’ at the University of Oslo in collaboration with the Utrecht University, the VU University in Amsterdam and the Museum of Natural History in Paris and included a wide range of techniques to analyze the mineral composition, chemistry and structures of the rocks combined with mathematical techniques in order to find out how the rocks formed

Estate planning in het kader van de Belastingregeling Nederland Curaçao

Grenzen van fiscale soevereinitei

A study on the BVOC emissions in Hong Kong

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A switch from horizontal compression to vertical extension in the Vrancea slab explained by the volume reduction of serpentine dehydration

The Vrancea slab, Romania, is a subducted remnant of the Tethyan lithosphere characterized by a significant intermediate-depth seismicity (60–170 km). A recent study showed a correlation between this seismicity and major dehydration reactions, involving serpentine minerals up to 130 km depth, and high-pressure hydrated talc deeper. Here we investigate the potential link between the triggering mechanisms and the retrieved focal mechanisms of 940 earthquakes, which allows interpreting the depth distribution of the stress field. We observe a switch from horizontal compression to vertical extension between 100 and 130 km depth, where the Clapeyron slope of serpentine dehydration is negative. The negative volume change within dehydrating serpentinized faults, expected mostly sub-horizontal in the verticalized slab, could well explain the vertical extension recorded by the intermediate-depth seismicity. This apparent slab pull is accompanied with a rotation of the main compressive stress, which could favour slab detachments in active subduction zones