Search results for "ACTIVATION"

Hydrocracking ofn-heptane with a NiO-MoO3/HYUS zeolite as catalyst. Kinetic study

1988

The hydrocracking of n-heptane has been carried out in a fixed bed reactor at 2.45 MPa pressure and with a H2/n-heptane molar ratio of 5.0 using a 4 wt% NiO - 8 wt% MO3/HYUS zeolite as a catalyst. The W/F10 ratio was varied between 75.3 and 1624 kg · s/kmol at different reaction temperatures: 573, 588, 603 and 623 K. The kinetics of the reaction has been studied by two different procedures due to the slight deactivation of the catalyst. One of them uses the conversion and yield values extrapolated at time on stream to zero and the other uses a kinetic equation where the deactivation of the catalyst has been included. The experimental data were fit well by a pseudo-first order kinetic equati…

Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.

2008

Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…

Analysis of the (H-2b x H-2k)F1Restricted Response to Insulin.

1984

The aim of these studies was to characterize the (H-2b X H-2k)F1-unique restriction element(s) responsible for presentation of bovine insulin (BI) to a long-term cultured T-cell line (BK-BI-1.2). (B10.BR X bm12)F1 spleen cells, which express a normal Ab alpha Ak beta molecule but a mutated Ak alpha Abm12 beta product on their cell surface, were perfectly able to act as BI-presenting cells. Antibody inhibition experiments with antibodies directed at I-Ak products revealed that monoclonal antibody 10-2.16, which reacts with the Ak beta polypeptide chain, abrogated BI-directed T-cell proliferation, whereas antibody H116-32.R5 with specificity for the Ak alpha chain was not inhibitory. These re…

6-Phosphofructokinase from frog skeletal muscle: purification and properties

1990

Investigation of the effect of intensive milling in a planetary ball mill on the thermal decomposition of basic nickel carbonate

2011

The kinetics of thermal decomposition of basic nickel carbonate NiCO3Ni?(OH)2?nH2O and the effect of intensive milling in a planetary ball mill on its parameters, have been investigated. The values of the reaction heat and of the activation energy of thermal decomposition have been determined. Investigations of the thermal decomposition of the products of ball milling of investigated compound revealed a distinct effect of milling on the reaction temperature and heat consumed during the thermal decomposition of investigated compound.

Experimental investigation and multi-scale modelling of the behavior of mechanically activated metallic powders : from binary systems to High Entropy…

2021

Generally, metal alloys consist of a main element associated with other elements present in smaller quantities such as iron, nickel, aluminum or copper alloys. The precise composition of an alloy is adjusted according to the required performance: high temperature behavior, corrosion resistance, mechanical properties, durability ... In 2004, a Taiwanese scientist, JW Yeh, had the idea of making an alloy base of several elements, at least 5, whose composition in the alloy varies between 5% and 30% at. Yeh invented the high entropy alloy (HEA). Mixed on a microscopic scale, the metals form a remarkably stable solid solution. The explanation is thermodynamic. An alloy is all the more stable as …

Can pressure-induced cell inactivation be related to cell volume compression? A case study for Saccharomyces cerevisiae

2013

In this paper, emphasis has been put on the relationship between volume compression and cell inactivation for the Saccharomyces cerevisiae strain CBS 1171 submitted to high hydrostatic pressure treatments. The influence of cell dehydration on pressure inactivation was first investigated. Inactivation was found to be strongly limited, or even completely prevented for cells with a water content of 60% w/w or below. Moreover, the volume compression undergone by a single yeast cell was assessed as a function of pressure and hydration conditions using a high-pressure setup for pressure-volume-temperature measurements. Direct measurements of volume compression were performed on cell pellets after…

Comparative analysis of two paradigm bacteriophytochromes reveals opposite functionalities in two-component signaling

2021

Bacterial phytochrome photoreceptors usually belong to two-component signaling systems which transmit environmental stimuli to a response regulator through a histidine kinase domain. Phytochromes switch between red light-absorbing and far-red light-absorbing states. Despite exhibiting extensive structural responses during this transition, the model bacteriophytochrome from Deinococcus radiodurans (DrBphP) lacks detectable kinase activity. Here, we resolve this long-standing conundrum by comparatively analyzing the interactions and output activities of DrBphP and a bacteriophytochrome from Agrobacterium fabrum (Agp1). Whereas Agp1 acts as a conventional histidine kinase, we identify DrBphP a…

Effect of electrolytical hydrogenation on the thermal stability and crystallization kinetics of METGLASS MBF-50

2007

The effect of electrolytical hydrogenation on both the surface and volume crystallization kinetics and thermal stability of amorphous alloy METGLASS MBF-50 has been investigated. The surface crystallization has been investigated by the exoelectron emission (EEE) technique, whereas the volume crystallization has been followed by differential thermal analysis (DTA). It has been found that both the surface and volume crystallization of investigated material occur in two stages. The surface crystallization occurs at temperature lower and with activation energy distinctly smaller than the volume crystallization. Hydrogenation of the investigated metallic glass enhances its thermal stability by i…

Effect of electrolytical hydrogenation on the thermal stability and crystallization kinetics of metallic glass Fe79Si9B12

2011

The effect of electrolytical hydrogenation on both the surface and volume crystallization kinetics and thermal stability of amorphous alloy Fe79Si9B12 has been investigated. The parameters of the surface and volume crystallization (temperature, activation energy) have been determined applying the exoelectron emission (EEE) and differential thermal analysis (DTA) methods, respectively. It has been found that the surface crystallization of investigated material occurs at temperature much lower and with activation energy smaller than the volume crystallization. The determination of the activation energies for the volume and surface crystallization by the combination of DTA and EEE techniques e…