Analysis of the role of different environmental effects in enzymatic catalysis. A hybrid quantum chemical and molecular mechanical study of acetylcholinesterase activity

1995 ◽  
Author(s):  
V. V. Vasilyev ◽  
A. A. Bliznyuk
Keyword(s):  
Environmental Effects ◽  
Quantum Chemical ◽  
Enzymatic Catalysis ◽  
Acetylcholinesterase Activity ◽  
Mechanical Study

Political Consumerism for Sustainable Tourism

2018 ◽  
pp. 348-366
Author(s):  
Machiel Lamers ◽  
Jeroen Nawijn ◽  
Eke Eijgelaar
Keyword(s):  
Nature Conservation ◽  
Environmental Change ◽  
Social Theory ◽  
Environmental Effects ◽  
Sustainable Tourism ◽  
Global Environmental Change ◽  
Future Research ◽  
Political Consumerism ◽  
Global Environmental

Over the last decades a substantial and growing societal and academic interest has emerged for the development of sustainable tourism. Scholars have highlighted the contribution of tourism to global environmental change and to local, detrimental social and environmental effects as well as to ways in which tourism contributes to nature conservation. Nevertheless the role of tourist consumers in driving sustainable tourism has remained unconvincing and inconsistent. This chapter reviews the constraints and opportunities of political consumerism for sustainable tourism. The discussion covers stronger pockets and a key weak pocket of political consumerism for sustainable tourism and also highlights inconsistencies in sustainable tourism consumption by drawing on a range of social theory arguments and possible solutions. The chapter concludes with an agenda for future research on this topic.

The Role of Hydrophobicity in Supramolecular Polymer/Surfactant Catalysts: An Understandable Model for Enzymatic Catalysis

2020 ◽  
Author(s):  
Paulo F.A. Costa ◽  
Rafael de Abreu ◽  
Andressa B. Fontana ◽  
Haidi D. Fiedler ◽  
Anthony J. Kirby ◽  
...  
Keyword(s):  
Enzymatic Catalysis ◽  
Supramolecular Polymer ◽  
Polymer Surfactant

scholarly journals Dynamics of Oxidation of Reduced Forms of CO2 under Electrochemical and Open-Сircuit Conditions on Polycrystalline Pt in H2CO3

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 274
Author(s):  
Alexander V. Smolin ◽  
Мikhail N. Mikhailov ◽  
Aleksey F. Gadzaov ◽  
Leonid M. Kustov
Keyword(s):  
Quantum Chemical ◽  
Preliminary Analysis ◽  
Oxidation Reaction ◽  
Density Functional ◽  
Oxidation Process ◽  
Open Circuit ◽  
Organic Substances ◽  
Oxidation Of Co ◽  
Reduced Forms

The problem of identifying correlations between catalytic and electrocatalytic processes is one of the fundamental problems of catalysis among “simple” organic substances, and the oxidation of CO and rCO2 is of great interest, since CO and CO2 are considered in pairs both during catalytic and electrocatalytic transformations. In the case of electrocatalysis, this analysis is important in the study of fuel cells. In this paper, we studied the correlation between the oxidation of reduced forms of CO2 (rCO2) under potentiodynamic-galvanoctatic electrochemical and open-circuit conditions of measurements on polycrystalline (pc)Pt in H2CO3. Periodic oscillations are revealed at the oxidation of Had and rCO2 on (pc)Pt. Quantum chemical calculations were carried out on the Pt13 cluster in order to identify the mechanisms of the rCO2 oxidation reaction. The correspondence in the energy parameters of the oxidation process of rCO2 under open-circuit conditions and electrochemical conditions is shown. The preliminary analysis of the system using density functional (DFT) calculations is carried out and the most stable systems that are based on Pt13 are found, namely rOH-Pt13-(CO)n, rOH-Pt13-(COH) and rOH-Pt13-(rCOOH). OH• species was chosen as the most likely candidate for the role of the oxidant for rCO2. Preliminary calculations for the expected reactions were carried out, and the optimal PES is revealed.

scholarly journals A Comparative Assessment of the Chronic Effects of Micro- and Nano-Plastics on the Physiology of the Mediterranean Mussel Mytilus galloprovincialis

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 649
Author(s):  
Marco Capolupo ◽  
Paola Valbonesi ◽  
Elena Fabbri
Keyword(s):  
Mytilus Galloprovincialis ◽  
Acetylcholinesterase Activity ◽  
Particle Sizes ◽  
Glutathione S Transferase ◽  
Phase Ii Metabolism ◽  
Chronic Effects ◽  
Mediterranean Mussel ◽  
Metabolism Enzyme ◽  
The Mediterranean

The ocean contamination caused by micro- and nano-sized plastics is a matter of increasing concern regarding their potential effects on marine organisms. This study compared the effects of a 21-day exposure to 1.5, 15, and 150 ng/L of polystyrene microplastics (PS-MP, 3-µm) and nanoplastics (PS-NP, 50-nm) on a suite of biomarkers measured in the Mediterranean mussel Mytilus galloprovincialis. Endpoints encompassed immunological/lysosomal responses, oxidative stress/detoxification parameters, and neurotoxicological markers. Compared to PS-MP, PS-NP induced higher effects on lysosomal parameters of general stress. Exposures to both particle sizes increased lipid peroxidation and catalase activity in gills; PS-NP elicited greater effects on the phase-II metabolism enzyme glutathione S-transferase and on lysozyme activity, while only PS-MP inhibited the hemocyte phagocytosis, suggesting a major role of PS particle size in modulating immunological/detoxification pathways. A decreased acetylcholinesterase activity was induced by PS-NP, indicating their potential to impair neurological functions in mussels. Biomarker data integration in the Mussel Expert System identified an overall greater health status alteration in mussels exposed to PS-NP compared to PS-MP. This study shows that increasing concentrations of nanoplastics may induce higher effects than microplastics on the mussel’s lysosomal, metabolic, and neurological functions, eventually resulting in a greater impact on their overall fitness.

scholarly journals Role of redox-inactive metals in controlling the redox potential of heterometallic manganese–oxido clusters

2021 ◽  
Author(s):  
Keisuke Saito ◽  
Minesato Nakagawa ◽  
Manoj Mandal ◽  
Hiroshi Ishikita
Keyword(s):  
Photosystem Ii ◽  
Redox Potential ◽  
Quantum Chemical Calculations ◽  
Catalytic Reaction ◽  
Quantum Chemical ◽  
Ionic Radius ◽  
Redox Potentials ◽  
Oxygen Evolving ◽  
Highest Occupied Molecular Orbitals

AbstractPhotosystem II (PSII) contains Ca2+, which is essential to the oxygen-evolving activity of the catalytic Mn4CaO5 complex. Replacement of Ca2+ with other redox-inactive metals results in a loss/decrease of oxygen-evolving activity. To investigate the role of Ca2+ in this catalytic reaction, we investigate artificial Mn3[M]O2 clusters redox-inactive metals  [M] ([M]  = Mg2+, Ca2+, Zn2+, Sr2+, and Y3+), which were synthesized by Tsui et al. (Nat Chem 5:293, 2013). The experimentally measured redox potentials (Em) of these clusters are best described by the energy of their highest occupied molecular orbitals. Quantum chemical calculations showed that the valence of metals predominantly affects Em(MnIII/IV), whereas the ionic radius of metals affects Em(MnIII/IV) only slightly.

scholarly journals The role of ammonia in sulfuric acid ion induced nucleation

2008 ◽  
Vol 8 (11) ◽  
pp. 2859-2867 ◽  
Author(s):  
I. K. Ortega ◽  
T. Kurtén ◽  
H. Vehkamäki ◽  
M. Kulmala
Keyword(s):  
Sulfuric Acid ◽  
Quantum Chemical ◽  
Local Minimum ◽  
Good Accuracy ◽  
Energy Surface ◽  
Ground Level ◽  
Computational Effort ◽  
Free Energy Surface ◽  
Large Clusters

Abstract. We have developed a new multi-step strategy for quantum chemical calculations on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good accuracy-to-computational effort ratio. We have applied this strategy to evaluate the relevance of ternary ion induced nucleation; we have also performed calculations for neutral ternary nucleation for comparison. The results for neutral ternary nucleation agree with previous results, and confirm the important role of ammonia in enhancing the growth of sulfuric acid clusters. On the other hand, we have found that ammonia does not enhance the growth of ionic sulfuric acid clusters. The results also confirm that ion-induced nucleation is a barrierless process at high altitudes, but at ground level there exists a barrier due to the presence of a local minimum on the free energy surface.

scholarly journals The Important Role of Halogen Bond in Substrate Selectivity of Enzymatic Catalysis

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Shuiqin Jiang ◽  
Lujia Zhang ◽  
Dongbin Cui ◽  
Zhiqiang Yao ◽  
Bei Gao ◽  
...  
Keyword(s):  
Halogen Bond ◽  
Enzymatic Catalysis ◽  
Substrate Selectivity
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