Kinetics of Plasmon-Driven Hydrosilylation of Silicon Surfaces: Photogenerated Charges Drive Silicon- Carbon Bond Formation

2021 ◽  
Author(s):  
Chengcheng Rao ◽  
Brian Olsen ◽  
Erik Luber ◽  
Jillian Buriak
Keyword(s):  
Green Light ◽  
Kinetic Studies ◽  
Silicon Surfaces ◽  
Moderate Intensity ◽  
Carbon Bond ◽  
Silicon Carbon ◽  
Set Up ◽  
Kinetics Of ◽  
Insight Into

Optically transparent PDMS stamps coated with a layer of gold nanoparticles were employed as plasmonic stamps to drive surface chemistry on silicon surfaces. Illumination of a sandwich of plasmonic stamps, an alkene ink, and hydride-terminated silicon with green light of moderate intensity drives hydrosilylation on the surface. The key to the mechanism of the hydrosilylation is the presence of holes at the Si-H-terminated interface, which is followed by attack by a proximal alkene and formation of the silicon-carbon bond. In this work, detailed kinetic studies of the hydrosilylation on silicon with different doping levels, n++, p++, n, p, and intrinsic were carried out to provide further insight into the role of the metal-insulator-semiconductor (MIS) junction that is set up during the stamping.

Kinetics of Plasmon-Driven Hydrosilylation of Silicon Surfaces: Photogenerated Charges Drive Silicon- Carbon Bond Formation

2021 ◽  
Author(s):  
Chengcheng Rao ◽  
Brian Olsen ◽  
Erik Luber ◽  
Jillian Buriak
Keyword(s):  
Green Light ◽  
Kinetic Studies ◽  
Silicon Surfaces ◽  
Moderate Intensity ◽  
Carbon Bond ◽  
Silicon Carbon ◽  
Set Up ◽  
Kinetics Of ◽  
Insight Into

Optically transparent PDMS stamps coated with a layer of gold nanoparticles were employed as plasmonic stamps to drive surface chemistry on silicon surfaces. Illumination of a sandwich of plasmonic stamps, an alkene ink, and hydride-terminated silicon with green light of moderate intensity drives hydrosilylation on the surface. The key to the mechanism of the hydrosilylation is the presence of holes at the Si-H-terminated interface, which is followed by attack by a proximal alkene and formation of the silicon-carbon bond. In this work, detailed kinetic studies of the hydrosilylation on silicon with different doping levels, n++, p++, n, p, and intrinsic were carried out to provide further insight into the role of the metal-insulator-semiconductor (MIS) junction that is set up during the stamping.

scholarly journals Dynamics of Tpm1.8 domains on actin filaments with single molecule resolution

2020 ◽  
Author(s):  
Ilina Bareja ◽  
Hugo Wioland ◽  
Miro Janco ◽  
Philip R. Nicovich ◽  
Antoine Jégou ◽  
...  
Keyword(s):  
Actin Filament ◽  
Single Molecule ◽  
Actin Filaments ◽  
High Probability ◽  
Actin Binding ◽  
Single Molecule Level ◽  
Filament Dynamics ◽  
Kinetics Of ◽  
Insight Into

ABSTRACTTropomyosins regulate dynamics and functions of the actin cytoskeleton by forming long chains along the two strands of actin filaments that act as gatekeepers for the binding of other actin-binding proteins. The fundamental molecular interactions underlying the binding of tropomyosin to actin are still poorly understood. Using microfluidics and fluorescence microscopy, we observed the binding of fluorescently labelled tropomyosin isoform Tpm1.8 to unlabelled actin filaments in real time. This approach in conjunction with mathematical modeling enabled us to quantify the nucleation, assembly and disassembly kinetics of Tpm1.8 on single filaments and at the single molecule level. Our analysis suggests that Tpm1.8 decorates the two strands of the actin filament independently. Nucleation of a growing tropomyosin domain proceeds with high probability as soon as the first Tpm1.8 molecule is stabilised by the addition of a second molecule, ultimately leading to full decoration of the actin filament. In addition, Tpm1.8 domains are asymmetrical, with enhanced dynamics at the edge oriented towards the barbed end of the actin filament. The complete description of Tpm1.8 kinetics on actin filaments presented here provides molecular insight into actin-tropomyosin filament formation and the role of tropomyosins in regulating actin filament dynamics.

Insight into the role of piperazine in the thermodynamics and nucleation kinetics of the triethylenediamine–methyl tertiary butyl ether system

CrystEngComm ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 948-956 ◽  
Author(s):  
Yufeng Quan ◽  
Yang Yang ◽  
Shijie Xu ◽  
Peipei Zhu ◽  
Shiyuan Liu ◽  
...  
Keyword(s):  
Crystal Size ◽  
Methyl Tertiary Butyl Ether ◽  
Nucleation Kinetics ◽  
Butyl Ether ◽  
Tertiary Butyl ◽  
System P ◽  
Kinetics Of ◽  
Insight Into ◽  
Ether System

Considering the role of piperazine in the TEDA–MTBE system, we investigate how to control the crystal size distribution.

Kinetic Studies on Oxidation of Veratryl Alcohol by Laccase-Mediator System. Part 1. Effects of Mediator Concentration

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Mikhail Yu. Balakshin ◽  
Chen-Loung Chen ◽  
Josef S. Gratzl ◽  
Adrianna G. Kirkman ◽  
Harald Jakob
Keyword(s):  
Kinetic Studies ◽  
Veratryl Alcohol ◽  
Alcohol Oxidation ◽  
Order Rate Constant ◽  
Molar Ratio ◽  
Active Centers ◽  
First Order ◽  
System Part ◽  
Kinetics Of

Summary Kinetics of the laccase-catalyzed oxidation of veratryl alcohol with dioxygen in the presence of 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diamonium salt (ABTS), the mediator, were studied to elucidate the possible reaction mechanism and the role of the mediator in this reaction. The reaction follows a pseudo-first order reaction law. The first order rate constant (κ) is dependent on the Mediator/Substrate (M/S) ratio and has a maximum at M/S molar ratio of 0.15. The kinetic studies show that the mechanism of veratryl alcohol oxidation with dioxygen-laccase-ABTS is rather complex and includes different reaction pathways. The mediator is involved in competitive reactions. It has been suggested that at low mediator concentration, the veratryl alcohol is oxidized via the laccase redox cycle. The mediator acts mostly as a laccase activator at a M/S ratio lower than 0.15. With increasing ABTS concentration with respect to the substrate concentration, ABTS acts increasingly as a cosubstrate competing with the original substrate for active centers of the laccase. This results in inhibition of veratryl alcohol oxidation in the enzyme cycle and increases the role of substrate oxidation by an oxidized mediator.

scholarly journals The active metabolic rate predicts a male spider's proximity to females and expected fitness

2013 ◽  
Vol 9 (2) ◽  
pp. 20121164 ◽  
Author(s):  
Michael M. Kasumovic ◽  
Frank Seebacher
Keyword(s):  
Citrate Synthase ◽  
Metabolic Rates ◽  
Web Spider ◽  
History Of ◽  
Orb Web ◽  
Set Up ◽  
Nephila Plumipes ◽  
Expected Fitness ◽  
Insight Into

Conspicuous traits, such as weaponry and body size, are often correlated with fitness. By contrast, we understand less about how inconspicuous physiological traits affect fitness. Not only is linking physiology directly to fitness a challenge, but in addition, behavioural studies most often focus on resting or basal metabolic rates, resulting in a poor understanding of how active metabolic rates affect fitness. Here we use the golden orb-web spider ( Nephila plumipes ), a species for which proximity to a female on the web predicts a male's paternity share, to examine the role of resting and active metabolic rates in fitness. Using a semi-natural experimental set-up, we show that males closer to a female have higher active metabolic rates than males further from females. This higher metabolic activity is paralleled by increased citrate synthase activity, suggesting greater mitochondrial densities. Our results link both higher active metabolic rates and increased citrate synthase activity with fitness. Coupled with the behaviour and life history of N. plumipes , these results provide insight into the evolution of physiological systems.

scholarly journals Decoding the Kinetic Limitations of Plasmon Catalysis: The Case of 4-Nitrothiophenol Dimerization

2020 ◽  
Author(s):  
Wouter Koopman ◽  
Radwan M. Sarhan ◽  
Felix Stete ◽  
Clemens N. Z. Schmitt ◽  
Matias Bargheer
Keyword(s):  
Thermal Effects ◽  
Dominant Role ◽  
Relative Importance ◽  
New Approach ◽  
Multistep Reaction ◽  
Kinetics Of ◽  
Complex Organic ◽  
Insight Into ◽  
Unique Ability

Plasmon-mediated chemistry presents an intriguing new approach to photocatalysis. However, the reaction enhancement<br>mechanism is not well understood. In particular, the relative importance of plasmon-generated hot charges and<br>photoheating are strongly debated. In this article, we evaluate the influence of microscopic photoheating on the kinetics of<br>a model plasmon-catalyzed reaction: the light-induced 4-nitrothiophenol (4NTP) to 4,4’-dimercaptoazobenzene (DMAB)<br>dimerization. Direct measurement of the reaction temperature by nanoparticle Raman-thermometry demonstrated that<br>the thermal effect plays a dominant role in the kinetic limitations of this multistep reaction. On the same time, no reaction<br>is possible by dark heating to the same temperature. This shows that plasmon nanoparticles have the unique ability to<br>enhance several steps of complex tandem reactions simultaneously. These results provide insight into the role of hot<br>electron and thermal effects in plasmonic catalysis of complex organic reactions, which highly important for the ongoing<br>development of plasmon based photosynthesis. <br>

scholarly journals Gendered assisted desistance: a decade from Corston

2018 ◽  
Vol 17 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Una Mairead Barr
Keyword(s):  
Criminal Justice ◽  
Justice System ◽  
Design Methodology ◽  
Qualitative Data ◽  
Binary Outcome ◽  
Content Type ◽  
Set Up ◽  
Community Projects ◽  
Insight Into

Purpose The purpose of this paper is to examine the role of assisted desistance from the perspective of women involved in the criminal justice system. It focusses on two community projects set up in the aftermath of the 2007 Corston Report, Northshire Women’s Centres (WCs) and the Housing for Northshire project. Design/methodology/approach Through analysis of a year of observation in these settings and 23 narrative interviews with staff and service users, the paper notes the differences between risk-focussed and desistance-focussed justice for women. Findings Neither projects are a panacea; however, they offer an insight into desistance-focussed practice. The findings would suggest that the projects provide social justice as opposed to criminal justice, particularly because of their flexible approach and awareness of the relational elements involved in female desistance. Originality/value The in-depth, qualitative data provided challenges the “payment by results” rhetoric which demands positivist research that promotes an understanding of desistance as a binary outcome. Implications for policy are considered.

scholarly journals New insight into the role of crosslinkers and composition on selectivity and kinetics of antimony uptake by chitosan-titania composite beads

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Padala Abdul Nishad ◽  
Anupkumar Bhaskarapillai ◽  
Madapuzi P. Srinivasan ◽  
Srinivasan Rangarajan
Keyword(s):  
Industrial Application ◽  
Binding Properties ◽  
Chitosan Beads ◽  
Design And Synthesis ◽  
Titania Content ◽  
Composite Beads ◽  
Crosslinked Chitosan ◽  
Kinetics Of ◽  
Insight Into

AbstractRole of composition and the nature of crosslinking on the properties of titania-chitosan beads have been investigated in detail. The investigations were done in order to explore the feasibility of design and synthesis of titania-chitosan beads with bespoke functionality based on the intended application. This would greatly enhance the potential for the industrial application of these biopolymer based beads. Beads of varying compositions (of titania and chitosan) were prepared and crosslinked using epichlorohydrin or glutaraldehyde. The physical characteristics and antimony binding properties of the resultant crosslinked titania-chitosan beads were investigated in detail. Influence of chitosan amount on swelling was seen to be more predominant in the glutaraldehyde crosslinked beads (TA-Cts-Glu). TA-Cts-Glu beads showed more swelling and better antimony (Sb(III) and Sb(V)) uptake as compared to the epichlorohydrin crosslinked beads (TA-CTS-Epi). While TA-Cts-Glu beads showed faster uptake kinetics compared to the TA-CTS-Epi beads, the latter showed selectivity towards Sb(III) against transition metal cations. Further, the beads exhibited differential uptake of Sb(V) and Sb(III). TA-Cts-Glu beads prepared with equal amounts of titania and chitosan showed the maximum Sb(V) uptake while the TA-Cts-Epi beads with higher chitosan to titania ratio showed the least. Sb(V) binding was enhanced by the crosslinked chitosan, while the Sb(III) uptake was aided predominantly by the titania content in the beads.

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