Directing on-surface polymerization via substrate-directed molecular template

2021 ◽  
Author(s):  
Siyi Gu ◽  
Shizhang Fu ◽  
Caimei Gong ◽  
Sihao Li ◽  
Xiaoqing Liu ◽  
...  
Keyword(s):  
Polymerization Process ◽  
Surface Polymerization ◽  
Molecular Nanostructures

Using template to control on-surface polymerization process is valuable for building functional molecular nanostructures. Here, the role of the symmetric matching between a halogen-ligand component (H2TBrPP) and substrate on the...

scholarly journals Exhaustive laccase-catalysed oxidation of a lignin model compound (vanillyl glycol) produces methanol and polymeric quinoid products

1985 ◽  
Vol 229 (1) ◽  
pp. 277-279 ◽  
Author(s):  
K Lundquist ◽  
P Kristersson
Keyword(s):  
Model Compound ◽  
Polymerization Process ◽  
Lignin Biodegradation ◽  
Simultaneous Formation ◽  
Initial Formation ◽  
Lignin Model Compound ◽  
Catalysed Oxidation ◽  
Visible Spectra ◽  
Lignin Model

Laccase-catalysed oxidation of the lignin-related phenol vanillyl glycol results in the initial formation of dimers and subsequent polymerization. The polymerization is accompanied by a liberation of methanol corresponding to 15-20% demethylation. Visible spectra together with reduction experiments suggest the simultaneous formation of o-quinones. The participation of quinone formation in the polymerization process and the possible role of such intermediates in lignin biodegradation is discussed.

scholarly journals Towards the realistic computer model of precipitation polymerization microgels

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vladimir Yu. Rudyak ◽  
Elena Yu. Kozhunova ◽  
Alexander V. Chertovich
Keyword(s):  
Computer Simulations ◽  
Precipitation Polymerization ◽  
Coarse Grained ◽  
Polymerization Process ◽  
New Horizons ◽  
Experimental Systems ◽  
Structure Factors ◽  
The Subject ◽  
First Time

Abstract In this paper we propose a new method of coarse-grained computer simulations of the microgel formation in course of free radical precipitation polymerization. For the first time, we simulate the precipitation polymerization process from a dilute solution of initial components to a final microgel particle with coarse grained molecular dynamics, and compare it to the experimental data. We expect that our simulation studies of PNIPA-like microgels will be able to elucidate the subject of nucleation and growth kinetics and to describe in detail the network topology and structure. Performed computer simulations help to determine the characteristic phases of the growth process and show the necessity of prolongated synthesis for the formation of stable microgel particles. We demonstrate the important role of dangling ends in microgels, which occupy as much as 50% of its molecular mass and have previously unattended influence on the swelling behavior. The verification of the model is made by the comparison of collapse curves and structure factors between simulated and experimental systems, and high quality matching is achieved. This work could help to open new horizons in studies that require the knowledge of detailed and realistic structures of the microgel networks.

scholarly journals On-surface Ullmann polymerization via intermediate organometallic networks on Ag(111)

2014 ◽  
Vol 50 (57) ◽  
pp. 7680-7682 ◽  
Author(s):  
Johanna Eichhorn ◽  
Thomas Strunskus ◽  
Atena Rastgoo-Lahrood ◽  
Debabrata Samanta ◽  
Michael Schmittel ◽  
...  
Keyword(s):  
Surface Polymerization ◽  
Ullmann Coupling

The role of organometallic intermediates during on-surface polymerization via Ullmann coupling was studied on Ag(111).

Manipulation on ZnO heterostructures: from binary ZnO–Ag to ternary ZnO–Ag–polypyrrole

CrystEngComm ◽  
2014 ◽  
Vol 16 (48) ◽  
pp. 10943-10948 ◽  
Author(s):  
Juan Li ◽  
Jian Yan ◽  
Chengzhan Liu ◽  
Lihong Dong ◽  
Hui Lv ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Uv Irradiation ◽  
Zinc Acetate ◽  
Catalytic Performance ◽  
Polymerization Process ◽  
Fast Reaction ◽  
Ternary Composite ◽  
Surface Polymerization

A ternary composite ZnO–Ag–polypyrrole was synthesized through a fast reaction between zinc acetate and hexamethylenetetramine followed by an in situ surface polymerization process. The sample exhibited a superior catalytic performance in the degradation of methylene blue under both UV irradiation and visible light.

Two Photon Polymerization Micro/Nanofabrication of Suspended Nanorods in Organically Modified Ceramics

NANO ◽  
2017 ◽  
Vol 12 (03) ◽  
pp. 1750033 ◽  
Author(s):  
Jieqiong Lin ◽  
Xian Jing ◽  
Mingming Lu ◽  
Yan Gu ◽  
Baojun Yu ◽  
...  
Keyword(s):  
Scanning Speed ◽  
Processing Parameters ◽  
Polymerization Process ◽  
Experimental Scheme ◽  
Two Photon ◽  
Threshold Theory ◽  
Organically Modified ◽  
Vertical Size ◽  
Two Photon Polymerization

Organically modified ceramics are used as photoresistors in the present work. The role of every ingredient played in two photon polymerization process is analyzed. A simple, compact and easy to locate experimental scheme is designed to fabricate nanorods in Ormocer. Based on the threshold theory of photon intensity, the lateral size dependences and vertical size dependences of nanorods on laser power and scanning speed are investigated, respectively. Through systematically changing processing parameters, a 136[Formula: see text]nm Ormocer suspended nanorod which is beyond diffraction limit resolution is obtained when [Formula: see text]m/s, [Formula: see text][Formula: see text]mW. By this means, two photon polymerization techniques show great potential to obtain a limiting resolution of Ormocer. What is more, micro gear, micro chair, photonic crystal and micro annular lens are fabricated in two photon polymerization in order to exhibit excellent mechanical and optical property of Ormocer.

Src family tyrosine kinase regulates acrosome reaction but not motility in porcine spermatozoa

Reproduction ◽  
2012 ◽  
Vol 144 (1) ◽  
pp. 67-75 ◽  
Author(s):  
María J Bragado ◽  
María C Gil ◽  
David Martin-Hidalgo ◽  
Ana Hurtado de Llera ◽  
Noelia Bravo ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Actin Polymerization ◽  
Acrosome Reaction ◽  
Polymerization Process ◽  
Spermatozoa Motility ◽  
Dependent Protein ◽  
Boar Spermatozoa ◽  
Porcine Spermatozoa

During the capacitation process, spermatozoa acquire the ability to fertilize an oocyte, and upregulation of cAMP-dependent protein tyrosine phosphorylation occurs. Recently, Src family tyrosine kinase (SFK) has been involved in spermatozoa capacitation as a key PKA-dependent tyrosine kinase in several species. This work investigates the expression and role of SFK in porcine spermatozoa. SFK members Lyn and Yes are identified in porcine spermatozoa by western blotting as well as two proteins named SFK1 and SFK2 were also detected by their tyrosine 416 phosphorylation, a key residue for SFK activation. Spermatozoa with SFK1 and SFK2 increase their Y416 phosphorylation time-dependently under capacitating conditions compared with noncapacitating conditions. The specific SFK inhibitor SU6656 unaffected porcine spermatozoa motility or viability. Moreover, SFK inhibition in spermatozoa under capacitating conditions leads to a twofold increase in both nonstimulated and calcium-induced acrosome reaction. Our data show that capacitating conditions lead to a time-dependent increase in actin polymerization in boar spermatozoa and that long-term incubation with SFK inhibitor causes a reduction in the F-actin content. In summary, this work shows that the SFK members Lyn and Yes are expressed in porcine spermatozoa and that SFK1 and SFK2 are phosphorylated (activated) during capacitation. Our results point out the important role exerted by SFK in the acrosome reaction, likely mediated in part by its involvement in the actin polymerization process that accompanies capacitation, and rule out its involvement in porcine spermatozoa motility.

scholarly journals Optical and Photoelectrochemical Investigation of Mixed Photoactive Poly 2,2’,5,2’’ ter-thiophene and Poly 2,2 bithiophene. Role of Intermixed Phases Created By the Co-electro-polymerization Process

2019 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Kasem K. Kasem ◽  
Monica Schultz ◽  
Sarah H. Osman
Keyword(s):  
Electrochemical Impedance ◽  
Polymer Networks ◽  
Outcome Data ◽  
Polymeric Films ◽  
Polymerization Process ◽  
Density Of State ◽  
Barrier Energy ◽  
Direct Band ◽  
P Type

Fluorine-doped tin oxide (FTO) electrodes modified with polymeric films of poly 2,2 bithiophene (PBth) and/or poly 2,2’,5,2’’-terthiophene (PTerth) were subjected to optical, photoelectrochemical (PEC), and electrochemical impedance spectroscopy (EIS) studies. Electropolymerization of mixed monomers containing bi-thiophene (Bth) and ter-thiophene (Terth) with different ratios resulted in the formation of intermixed phases. The recorded optical and PEC and EIS outcome data show that these intermixed polymer networks do not follow a monotonic relationship with the monomer ratios used to generate them. Optical studies indicate the formation of indirect and direct band gaps in the intermixed phases. Films generated in mixed monomers have greater energy-band tails than those generated from pure monomers. PEC studies indicated that these intermixed phases possess p-p type hole accumulations, evident from the initial sharp rise in photocurrent. EIS results did not support linear relationship between the percent of Bth in monomer mixture and the dielectric-related properties such as barrier energy Wm, hopping frequency (ω hopping), electrical conductivity (σ), and density of state at Fermi level N (EF).

Mathematical modelling of platelet rich plasma clotting. Pointwise unified model

2018 ◽  
Vol 33 (5) ◽  
pp. 265-276 ◽  
Author(s):  
Anna A. Andreeva ◽  
Mohan Anand ◽  
Alexey I. Lobanov ◽  
Andrey V. Nikolaev ◽  
Mikhail A. Panteleev ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Sol Gel ◽  
Unified Model ◽  
Polymerization Process ◽  
Factor Vii ◽  
Clotting Factors ◽  
Rosenbrock Method ◽  
Sensitivity Analysis Method ◽  
Sol Gel Transition

AbstractThe mechanistic modelling of blood clotting and fibrin-polymer mesh formation is of significant value for medical and biophysics applications. This paper presents a combination of two pointwise kinetic models represented by system of ODEs. One of them represents the reaction dynamics of clotting factors including the role of the platelet membranes. The second one describes the fibrin-polymer formation as a multistage polymerization process with a sol-gel transition at the final stage. Complex-value second order Rosenbrock method (CROS) is employed for the computational experiments. A sensitivity analysis method built into the computational scheme helps clarify non-evident dependencies in the exhaustive system of ODEs. The unified model was primarily verified using conditions of factor VII deficiency. The model, however requires a significant effort to be tested against experimental data available.

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