γ-Alumina: The Essential and Unexpected Role of Water for the Structure, Stability, and Reactivity of “Defect” Sites

2012 ◽  
Vol 134 (35) ◽  
pp. 14430-14449 ◽  
Author(s):  
Raphael Wischert ◽  
Pierre Laurent ◽  
Christophe Copéret ◽  
Françoise Delbecq ◽  
Philippe Sautet
Keyword(s):  
Structure Stability ◽  
Defect Sites

The role of the C-terminus and Kpn loop in the quaternary structure stability of nucleoside diphosphate kinase from Leishmania parasites

2015 ◽  
Vol 192 (3) ◽  
pp. 336-341 ◽  
Author(s):  
Plínio Salmazo Vieira ◽  
Priscila Oliveira de Giuseppe ◽  
Arthur Henrique Cavalcante de Oliveira ◽  
Mario Tyago Murakami
Keyword(s):  
Quaternary Structure ◽  
Nucleoside Diphosphate Kinase ◽  
Structure Stability ◽  
C Terminus ◽  
Leishmania Parasites

Insight into structure, stability and hydrogen bond in complexes of guanine and thymine at the molecular level using computational chemical method

2021 ◽  
Vol 11 (1) ◽  
pp. 127-134
Author(s):  
Nhung Ngo Thi Hong ◽  
Huong Dau Thi Thu ◽  
Trung Nguyen Tien
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Energy Surface ◽  
Covalent Bond ◽  
Electrostatic Energy ◽  
Substantial Contribution ◽  
Structure Stability ◽  
Dispersion Terms ◽  
Insight Into

Nine stable structures of complexes formed by interaction of guanine with thymine were located on potential energy surface at B3LYP/6-311++G(2d,2p). The complexes are quite stable with interaction energy from -5,8 to -17,7 kcal.mol-1. Strength of complexes are contributed by hydrogen bonds, in which a pivotal role of N−H×××O/N overcoming C−H×××O/N hydrogen bond, up to to 3.5 times, determines stabilization of complexes investigated. It is found that polarity of N/C−H covalent bond over proton affinity of N/O site governs stability of hydrogen bond in the complexes. The obtained results show that the N/C−H×××O/N red-shifting hydrogen bonds occur in all complexes, and a larger magnitude of an elongation of N−H compared C-H bond length accompanied by a decrease of its stretching frequency is detected in the N/C−H×××O/N hydrogen bond upon complexation. The SAPT2+ analysis indicates the substantial contribution of attractive electrostatic energy versus the induction and dispersion terms in stabilizing the complexes.

The role of keto defect sites for the emission properties of polyfluorene-type materials

2003 ◽  
Vol 139 (3) ◽  
pp. 759-763 ◽  
Author(s):  
Emil J.W List ◽  
M Gaal ◽  
Roland Guentner ◽  
Patricia Scandiucci de Freitas ◽  
Ullrich Scherf
Keyword(s):  
Emission Properties ◽  
Defect Sites

Ego-network stability and exploratory innovation: the moderating role of knowledge networks

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jingbei Wang ◽  
Naiding Yang ◽  
Min Guo
Keyword(s):  
Moderate Level ◽  
Knowledge Networks ◽  
Structure Stability ◽  
Network Stability ◽  
Content Type ◽  
Exploratory Innovation ◽  
Moderating Role ◽  
Local Cohesion ◽  
Global Cohesion

PurposePrevious studies examined the effect of inter-organizational collaboration relationships on organizational innovation. However, most focused on the configuration of the network from the static network perspective, and few examined the influence of network structure stability on an organization's exploratory innovation from the ego-network perspective. This study addresses this research gap by focusing on ego-network stability and its effect on an organization's exploratory innovation.Design/methodology/approachThe empirical setting is the smartphone collaboration network from 2004 to 2017. We selected one-site schemes and panel data of patents from the Derwent Innovation Database. A negative binomial model with fixed effects was used to test our hypotheses.FindingsThe regression results show that an organization's ego-network stability has an inverted-U-shaped relationship with its exploratory innovation. Global cohesion of the focal organization's knowledge network moderates the process in such a way that when it is at a high level, an organization's exploratory innovation can benefit more from a moderate level of ego-network stability. However, local cohesion moderates in such a way that, at a low level, an organization's exploratory innovation can benefit more from a moderate level of ego-network stability.Originality/valueThis study highlights the importance of ego-network stability and its effect on the focal organization's exploratory innovation. It contributes to the literature on the relationship between ego-network stability and exploratory innovation by investigating the moderating role of global cohesion and local cohesion in knowledge networks.

Structure, stability, and chaperone function of αA-crystallin: Role of N-terminal region

Biopolymers ◽  
2007 ◽  
Vol 86 (3) ◽  
pp. 177-192 ◽  
Author(s):  
Madhuchhanda Kundu ◽  
P. C. Sen ◽  
K. P. Das
Keyword(s):  
Terminal Region ◽  
Structure Stability ◽  
Chaperone Function

scholarly journals The role of mixotrophy in plankton bloom dynamics, and the consequences for productivity

2005 ◽  
Vol 62 (5) ◽  
pp. 833-840 ◽  
Author(s):  
Astrid C. Hammer ◽  
Jonathan W. Pitchford
Keyword(s):  
Phytoplankton Bloom ◽  
Equilibrium Structure ◽  
Structure Stability ◽  
Type I ◽  
Single Individual ◽  
Predator Prey ◽  
Type Iii ◽  
Predator Prey Model ◽  
Plankton Bloom

Abstract Mixotrophy (=heterotrophy and photosynthesis by a single individual) is a common phenomenon in aquatic ecosystems, in particular under light- or nutrient-limitation. However, it is not usually considered in mathematical models of biological populations. This paper shows how different types of mixotrophy might be usefully incorporated into a general predator–prey model, and explores the consequences for plankton bloom dynamics and productivity. It is demonstrated, analytically and numerically, that even small levels of type III mixotrophy (a small fraction of the zooplankton also being involved in primary production) have significant effects on a system's equilibrium structure, stability, and short-term dynamics. Type III mixotrophy has a stabilizing effect on the system by reducing its excitability, i.e. its propensity to exhibit blooms. Compared with the non-mixotrophic benchmark, for a phytoplankton bloom to be triggered in a system with type III mixotrophy, a much larger perturbation is necessary. Type II mixotrophy (a small fraction of algae engage in phagotrophy) and type I mixotrophy (equal phagotrophy and phototrophy) are briefly discussed. The potential consequences for productivity are also studied. Our results indicate that the phytoplankton–zooplankton system becomes more productive in the presence of type III mixotrophy.

scholarly journals The role of thermal analysis in the development of high-iron-content kaolinite-based photocatalysts

2020 ◽  
Vol 142 (1) ◽  
pp. 289-299
Author(s):  
Veronika Vágvölgyi ◽  
Katalin Győrfi ◽  
Balázs Zsirka ◽  
Erzsébet Horváth ◽  
János Kristóf
Keyword(s):  
Iron Content ◽  
Adsorbed Water ◽  
Acid Base ◽  
High Iron Content ◽  
High Iron ◽  
Defect Sites ◽  
Heating Water ◽  
Coordinated Water

Abstract Dynamic and controlled-rate thermogravimetric analyses have been carried out on acid-treated (11 and 5.8 M HCl), high-iron-content kaolinites as potential photocatalysts. The mineral contaminants were determined by XRD, while the defect sites of reduced coordination number obtained by surface treatments were identified with 27Al MAS NMR spectroscopy. Upon heating, water is evolved from the surface-treated samples in three main stages: (1) removal of adsorbed water up to ~ 200 °C, (2) goethite dehydroxylation between 200 and 350 °C and (3) dehydroxylation of the clay in the 300–700 °C temperature range. Identification of water released from the above mass loss steps is difficult due to the significant overlap of steps 2 and 3, as well as to the presence of coordinated water at broken edges and defect sites (–OH2+ groups). As a result, the thermal behavior of surface-treated kaolinites should be taken into account both in the preparation of hybrids/composites and in the acid–base characterization of the catalytic surface.

scholarly journals The Role of Defect Sites in Nanomaterials for Electrocatalytic Energy Conversion

Chem ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 1371-1397 ◽  
Author(s):  
Yi Jia ◽  
Kun Jiang ◽  
Haotian Wang ◽  
Xiangdong Yao
Keyword(s):  
Energy Conversion ◽  
Defect Sites
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