scholarly journals A Review of Enzyme Induced Carbonate Precipitation (EICP): The Role of Enzyme Kinetics

2021 ◽  
Vol 2 (1) ◽  
pp. 92-114
Author(s):  
Isaac Ahenkorah ◽  
Md Mizanur Rahman ◽  
Md Rajibul Karim ◽  
Simon Beecham ◽  
Christopher Saint
Keyword(s):  
Oil Recovery ◽  
Ground Improvement ◽  
Kinetic Properties ◽  
Carbonate Precipitation ◽  
Theoretical Understanding ◽  
Sustainable Engineering ◽  
Urease Enzyme ◽  
Potential Applications

Enzyme-induced carbonate precipitation (EICP) is a relatively new bio-cementation technique for ground improvement. In EICP, calcium carbonate (CaCO3) precipitation occurs via urea hydrolysis catalysed by the urease enzyme sourced from plants. EICP offers significant potential for innovative and sustainable engineering applications, including strengthening of soils, remediation of contaminants, enhancement of oil recovery through bio-plugging and other in situ field applications. Given the numerous potential applications of EICP, theoretical understanding of the rate and quantity of CaCO3 precipitation via the ureolytic chemical reaction is vital for optimising the process. For instance, in a typical EICP process, the rate and quantity of CaCO3 precipitation can depend significantly on the concentration, activity and kinetic properties of the enzyme used along with the reaction environment such as pH and temperature. This paper reviews the research and development of enzyme-catalysed reactions and its applications for enhancing CaCO3 precipitation in EICP. The paper also presents the assessment and estimation of kinetic parameters, such as the maximal reaction velocity (Vmax) and the Michaelis constant (Km), that are associated with applications in civil and geotechnical engineering. Various models for evaluating the kinetic reactions in EICP are presented and discussed, taking into account the influence of pH, temperature and inhibitors. It is shown that a good understanding of the kinetic properties of the urease enzyme can be useful in the development, optimisation and prediction of the rate of CaCO3 precipitation in EICP.

The skyrmion annihilations induced by local reversal of background field in skyrmion lattice

2022 ◽  
Author(s):  
Yang Li ◽  
Hua Pang
Keyword(s):  
Stable State ◽  
Topological Defects ◽  
Background Field ◽  
Information Storage ◽  
Uniform Field ◽  
Annihilation Process ◽  
Complex Process ◽  
Potential Applications

Abstract The understanding of the creation and annihilation dynamics of a magnetic skyrmion is significant due to its potential applications in information storage and spintronics. Although there have been extensive investigations on the annihilation of isolated skyrmion, topological annihilation in periodic skyrmion lattice is a more complex process. We report a micromagnetic simulation study about the annihilation process of a two-dimensional skyrmion triangular lattice triggered by a uniform field HREV of comparable size to the skyrmion, which is opposite to the direction of the background field, revealing two annihilation modes. When the HREV center is within the range of a skyrmion, the neighboring skyrmions annihilate in situ, while the center is between adjacent skyrmions, anti-skyrmion is induced in the interstitial region. Both mechanisms tend to experience the intermediate topological vortex or antivortex structure, and the spin system undergoes a long period of relaxation to reach a stable state after the topological charge is stabilized. Our results present a local annihilation scheme that is easy to achieve in a 2D skyrmion lattice and highlight the role of interaction between skyrmions in the transformation between different kinds of topological defects.

Growth of Boron Nanowires by Chemical Vapor Deposition

2007 ◽  
Vol 1017 ◽  
Author(s):  
Li Guo ◽  
Raj N. Singh
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Mechanisms ◽  
Nano Structures ◽  
Gas Chemistry ◽  
Potential Applications ◽  
Vls Growth ◽  
Boron Nanowires

AbstractMotivated by the extensive research on carbon nanotubes (CNTs), boron and its related nano-structures have attracted increasing interests for potential applications in nanodevices and nanotechnologies due to their extraordinary properties. B-related nanostructures are successfully grown on various substrates in a CVD process. The boron nanowires have diameters around 50-200 nanometers and lengths up to a few microns. The gas chemistry is monitored by the in-situ mass-spectroscopy, which helps to identify reactive species in the process. Modified vapor-solid growths as well as VLS growth mechanisms are proposed for the growth of these nanostructures. The role of the catalysts in the synthesis is also discussed.

scholarly journals Inhibition of GSK-3 to induce cardiomyocyte proliferation: a recipe for in situ cardiac regeneration

2018 ◽  
Vol 115 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Anand Prakash Singh ◽  
Prachi Umbarkar ◽  
Yuanjun Guo ◽  
Thomas Force ◽  
Manisha Gupte ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Cardiac Regeneration ◽  
Cardiomyocyte Proliferation ◽  
Short Supply ◽  
Injured Myocardium ◽  
Proliferation And Differentiation ◽  
Potential Applications ◽  
Specific Deletion

Abstract With an estimated 38 million current patients, heart failure (HF) is a leading cause of morbidity and mortality worldwide. Although the aetiology differs, HF is largely a disease of cardiomyocyte (CM) death or dysfunction. Due to the famously limited amount of regenerative capacity of the myocardium, the only viable option for advanced HF patients is cardiac transplantation; however, donor’s hearts are in very short supply. Thus, novel regenerative strategies are urgently needed to reconstitute the injured hearts. Emerging data from our lab and others have elucidated that CM-specific deletion of glycogen synthase kinase (GSK)-3 family of kinases induces CM proliferation, and the degree of proliferation is amplified in the setting of cardiac stress. If this proliferation is sufficiently robust, one could induce meaningful regeneration without the need for delivering exogenous cells to the injured myocardium (i.e. cardiac regeneration in situ). Herein, we will discuss the emerging role of the GSK-3s in CM proliferation and differentiation, including their potential implications in cardiac regeneration. The underlying molecular interactions and cross-talk among signalling pathways will be discussed. We will also review the specificity and limitations of the available small molecule inhibitors targeting GSK-3 and their potential applications to stimulate the endogenous cardiac regenerative responses to repair the injured heart.

scholarly journals Conductive Cotton by In Situ Laccase-Polymerization of Aniline

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1023 ◽  
Author(s):  
Jing Su ◽  
Euijin Shim ◽  
Jennifer Noro ◽  
Jiajia Fu ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Cotton Fabrics ◽  
Wearable Electronics ◽  
Polymerization Degree ◽  
Reaction Conditions ◽  
Ultrasonic Bath ◽  
Potential Applications ◽  
Aniline Oxidation ◽  
Conductive Textile

Conductive cotton fabrics were obtained via in situ aniline polymerization by laccase from Myceliophthora thermophila under mild reaction conditions without the addition of strong proton acids. The reactions were conducted using two types of reactors, namely a water bath (WB) and an ultrasonic bath (US), and the role of a mediator, 1-hydroxybenzotriazol (HBT), on the laccase-assisted polymerization of aniline was investigated. A similar polymerization degree was obtained when using both reactors—however, the ultrasonic bath allowed the experiments to be conducted in shorter periods of time (24 h for WB vs. 2 h for US). The data obtained also revealed that the mediator (1-hydroxybenzotriazol-HBT) played a crucial role in aniline oxidation. A higher conversion yield and polymerization degree were obtained when the reaction was conducted in the presence of this compound, as confirmed by MALDI-TOF analysis. The cotton fabrics coated with polyaniline presented deep coloration and conductivity, especially when the mediator was included on the reactional system. The results obtained are a step forward in the enzymatic polymerization of aniline with the purpose of obtaining coloured conductive textile surfaces, with potential applications in wearable electronics.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Influence of social networks on business processes’ development

2020 ◽  
Vol 19 (12) ◽  
pp. 2225-2252
Author(s):  
E.V. Popov ◽  
V.L. Simonova ◽  
O.V. Komarova ◽  
S.S. Kaigorodova
Keyword(s):  
Social Networks ◽  
Social Media ◽  
Business Models ◽  
Business Processes ◽  
Digital Economy ◽  
Theoretical Understanding ◽  
Sales Channels ◽  
A Value ◽  
The Impact

Subject. The emergence of new ways of interaction between sellers and buyers, the formation of new sales channels and product promotion based on the use of digital economy tools is at the heart of improving the business processes. Social networks became a tool for development; their rapid growth necessitates theoretical understanding and identification of potential application in enterprise's business process digitalization. Objectives. We explore the role of social media in the digitalization of business processes, systematize the impact of social networks on business processes of enterprises in the digital economy. Methods. The theoretical and methodological analysis of social networks as a tool for digitalization of company's business processes rests on the content analysis of domestic and foreign scientific studies, comparison, generalization and systematization. Results. We highlight the key effects of the impact of social networks on the business processes of the company; show that the digitalization of business processes should be considered in the context of a value-based approach, aimed at creating a value through the algorithmization of company operations. We determine that social networks are one of the most important tools for digitalization of company's business processes, as they have a high organizational and management potential. We also systematize the effects of social media on company's business processes. Conclusions. We present theoretical provisions of the impact of social networks on business processes of enterprises, which will enable to model and organize ideas about the development of digital ecosystems and the formation of business models.

SUSTAINABLE LIVELIHOOD THROUGH SKILL DEVELOPMENT AMONG RURAL YOUTH: ROLE OF MICRO-FINANCE IN THE DEVELOPMENTAL PARADIGM

2017 ◽  
Vol 14 (1) ◽  
pp. 156-173
Author(s):  
Vikram Singh
Keyword(s):  
Social Interactions ◽  
Skill Development ◽  
Well Being ◽  
Rural Youth ◽  
Inclusive Development ◽  
Sustainable Livelihood ◽  
Theoretical Understanding ◽  
Societal Structure ◽  
Policy Shifts

This  article  attempts to  analyse  the  process  of  sustainable  livelihood  through skill development and its conceptual and theoretical understanding in India with reference to rural youth. In India skill development is demanded for economic growth and inclusive development; hence the rural population cannot be overlooked. Employable skills alone have not been able to generate sufficient employment among rural youth or address/promote well-being and sustainable livelihood. Various frameworks associated with skill development leave scope for reforms to strengthen the implementation of various policy shifts in respect of rural development and government/non-government organisations. The process of skill development for rural youth through the establishment of institutions, launch of policy/programmes and their linkages with micro-finance are considered, as the distinctive nature and features of micro-finance in relation to the forces of societal structure, social relationships, and social interactions leading towards collective interests and norms that shape the lives of rural youth. Lastly, analysis is done and conclusions drawn on the basis of discussion.

{10-12} Twinning Mechanism During In Situ Micro-Tensile Loading of Pure Mg: Role of Basal Slip and Twin-Twin Boundary Interaction

2020 ◽  
Author(s):  
Nicolò Maria della Ventura ◽  
Szilvia Kalácska ◽  
Daniele Casari ◽  
Thomas Edward James Edwards ◽  
Johann Michler ◽  
...  
Keyword(s):  
Twin Boundary ◽  
Basal Slip ◽  
Tensile Loading ◽  
Boundary Interaction
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