Activation energy

A reaction happens need the energy to vibrate the molecules and the reactant concentration enough. The energy here is often provided by heat. However, in living system, high temperature may harm the biological structure Truly that the concentration in living system is very low. So living organisms solve these problems by using enzyme

94p zingzing09 21-10-2012 66 9   Download

Tham khảo bài thuyết trình 'chapter 5. lipid metabolism', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

64p zingzing09 21-10-2012 62 7   Download

This work demonstrated the potential of US for mitigating membrane fouling. However, the integration of the US transducers within the membrane system will be a major challenge for the application of US in membrane cleaning. It is more appropriate that US is used as pre-treatment to the membrane system, the transducers can be placed prior to the coagulant feed line. Further work on the determination of the detailed mechanisms associated with enhancing coagulation would enable optimisation of the system with regard to process, cost and energy efficiency.

108p runthenight05 01-03-2023 16 3   Download

The purpose of the thesis is described as follows: To develop an independent simulation model for IEEE 803.2az Energy Efficient Ethernet Standards with Active and Idle modes of operations; To design and simulate a traffic source generator with exponentially distributed inter-arrival periods, and forecast the duration of the next idle periods, based in the distribution of packet arrivals; To extend the simulation of Dynamic power management in Access networks with the inclusion of prioritized traffic, which changes the duration of low power modes;…

141p runthenight07 01-03-2023 10 3   Download

The aim of this project is to provide a summary of the current knowledge on energy recovery options from wastewater treatment plants sludge and/or biosolids. This covers technologies as well as data from case studies and research experimental results. The focus of the study is the ATP. The project methodology comprised two stages. The first stage involved a review of the current literature.

166p runthenight07 01-03-2023 9 3   Download

The experience of previous oil price shocks has shown that these shocks can provide an important catalyst for policies to encourage demand reduction, substitution to other fuels, and development of new sources of energy supply.

11p maingoc84 28-12-2022 35 4   Download

The main objective of the thesis is to provide general methods to control oscillation based on measurement of energy flow, namely: Find the optimal solution for passive control systems based on energy flows; propose the semi-active control algorithms to control the energy flow.

27p capheviahe27 23-02-2021 20 3   Download

The paper presents the study of high harmonics influence on power metering by static meters for active and reactive energy. The review and analysis of manufacturer’s documents and standards in the field of electricity meters testing was conducted and mathematical models for calculating active and reactive energy were identified.

6p lucastanguyen 01-06-2020 12 1   Download

This paper describes the preparation, optical properties and the role of the concentration of rare earth ions (RE: Eu, Er, Tb, Yb) as active centers in the energy transfer of Y2O3: RE nanophosphors. The materials are prepared by the combustion method using urea or glycine. Nanoparticles can be prepared with sizes ranging from 5 to 100 nm and can be estimated by high resolution TEM. Optimization of Eu and Er content in these nanophosphors was reported. The effect of energy transfer between Tb and Eu and the up-conversion between Er and Yb were studied.

8p 12120609 01-06-2020 16 1   Download

Nuclear decommissioning is a worldwide competitive market. It is also the main source of radioactive waste from the nuclear energy field. In order to reduce the waste volume it is necessary to sort the actual radioactive waste to be disposed of and to separate them from other materials that could be recycled.

5p christabelhuynh 29-05-2020 13 0   Download

This paper presents a comprehensive scientometrics on the existing trend on mesoporous materials in chemistry. The study uses Web of Science database as the primary source of value added articles and performs different methods for detecting highly cited articles, most active countries, etc.

18p tocectocec 25-05-2020 16 2   Download

This article discusses possibilities of application of widely applied and promoted abroad methods of active dampening of vibration and pressure oscillations (antinoise technology) in order to reduce vibration transfer via vibro-insulating couplings (compensators) of fluid pipelines.

8p tohitohi 19-05-2020 16 0   Download

The objectives of the thesis: Study on materials fabrication technology; structural - photocatalytic properties of TiO2 material, and TiO2 as the nanostructured variant. On the basis of such material system, the systematic and quantitative study on hydrophilicity or, in other words, the study of surface energy of material systems under Exciation of UV light radiation. Further clarification of the correlation between photocatalytic activity, self-cleaning and hydrophobicity of TiO2 nanostructured materials.

32p xacxuoc4321 09-07-2019 31 5   Download

Pyrolysis to produce bio-oil from sewage sludge is a promising way, to not only improve the economical value, but also to reduce pollutants associated with sludge. The aim of this study was to evaluate the production of oil from primary, waste activated and digested sludges.

8p tuananhhumg 04-11-2013 58 2   Download

Certain amino acids, like glutamine and leucine, induce an anabolic response in liver. They activate p70 ribosomal protein S6 kinase (p70S6K) and acetyl-CoA carboxylase (ACC) involved in protein and fatty acids synthesis, respectively. In contrast, the AMP-activated protein kinase (AMPK), which senses the energy state of the cell and becomes activated under metabolic stress, inactivates by phosphorylation key enzymes in biosynthetic pathways thereby conserving ATP.

9p system191 01-06-2013 50 5   Download

The design of b-glycosidases with planed substrate specificity for biotechnological application has received little attention. This is mostly a consequence of the lack of data on the molecular basis of the b-glycosidase specificity, namely data on the energy of the noncovalent interactions in the enzymetransition state complex. In an attempt to fill this gap, sitedirected mutagenesis and enzyme steady-state kinetic experiments with different substrates were conducted, using as model a digestive b-glycosidase (glycoside hydrolase family 1) from Spodoptera frugiperda (Lepidoptera) (Sfbgly50).

10p system191 01-06-2013 44 4   Download

Mikrobiologisches Institut der Eidgeno¨ssischen Technischen Hochschule, ETH-Zentrum, Zu¨rich, Switzerland The membrane-bound b subunit of the oxaloacetate decarboxylase Na+ pump of Klebsiella pneumoniae catalyzes the decarboxylation of enzyme-bound biotin. This event is coupled to the transport of 2 Na+ ions into the periplasm and consumes a periplasmically derived proton. The connecting fragment IIIa and transmembrane helices IV and VIII of the b subunit are highly conserved, harboring residues D203, Y229, N373, G377, S382, and R389 that play a profound role in catalysis. ...

8p system191 01-06-2013 33 4   Download

Mitochondrial functional and structural impairment and generation of oxidative stress have been implicated in aging, various diseases and chemotherapies. This study analyzed azidothymidine (AZT)-caused failures in mitochondrial functions, in redox regulation and activation of the HIV-1 gene expression. We monitored intracellular concentrations of ATP and glutathione (GSH) as the indicators of energy production and redox conditions, respectively, during the time-course experiments with U937 and MOLT4 human lymphoid cells in the presence of AZT (0.05 mgÆmL)1) or H2O2 (0.01 mM) for 15–25 days.

7p system191 01-06-2013 43 3   Download

In an effort to explore the role of glycine clusters on the cold adaptation of enzymes, we designed point mutations aiming to alter the distribution of glycine residues close to the active site of the psychrophilic alkaline phosphatase from the Antarctic strain TAB5. The mutagenesis targets were residues Gly261 and Gly262. The replacement of Gly262 by Ala resulted in an inactive enzyme. Substitution of Gly261 by Ala resulted to an enzyme with lower stability and increased energy of activation.

6p research12 01-06-2013 37 5   Download

Na + /K + -ATPase as an energy transducing ion pump has beenstudiedextensivelysince itsdiscovery in1957.Although early findings suggested a role for Na + /K + -ATPase in regulation of cell growth and expression of various genes, only in recent years the mechanisms through which this plasma membrane enzyme communicates with the nucleus have been studied.

6p research12 29-04-2013 34 4   Download