Search query: Self-inhibition effect of metal

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abstract: Significance Understanding and controlling the incorporation of metal into nanoscaled semiconductor is foundational for semiconductor processing. Through theoretical calculation and experimental results, we reveal that the interstitial atoms in the Si lattice such as Mn can quickly diffuse out of Si nanowires conveniently, thus can achieve high purity of Si nanowires. This finding of self inhibition effect not only provides understanding of impurity incorporation at nanoscale, but also provides an extra knob for rational catalyst designs of nanoscale building blocks, and fine tuning their electrical, optical, and thermal properties for various applications. There has been a persistent effort to understand and control the incorporation of metal impurities in semiconductors at nanoscale, as it is important for semiconductor processing from growth, doping to making contact. Previously, the injection of metal atoms into nanoscaled semiconductor, with concentrations orders of magnitude higher than the equilibrium solid solubility, has been reported, which is often deemed to be detrimental. Here our theoretical exploration reveals that this colossal injection is because gold or aluminum atoms tend to substitute Si atoms and thus are not mobile in the lattice of Si. In contrast, the interstitial atoms in the Si lattice such as manganese (Mn) are expected to quickly diffuse out conveniently. Experimentally, we confirm the self inhibition effect of Mn incorporation in nanoscaled silicon, as no metal atoms can be found in the body of silicon (below 1017 atoms per cm 3) by careful three dimensional atomic mappings using highly focused ultraviolet laser assisted atom probe tomography. As a result of self inhibition effect of metal incorporation, the corresponding field effect devices demonstrate superior transport properties. This finding of self inhibition effect provides a missing piece for understanding the metal incorporation in semiconductor at nanoscale, which is critical not only for growing nanoscale building blocks, but also for designing and processing metal semiconductor structures and fine tuning their properties at nanoscale.
author_names: Bin Zhu

Ding Yi

Yuxi Wang

Hongyu Sun

Gang Sha

Gong Zheng

Erik C Garnett

Bozhi Tian

Feng Ding

Jia Zhu
title: Self inhibition effect of metal incorporation in nanoscaled semiconductors
venue: Proceedings of the National Academy of Sciences
year: 2021

abstract: The intricate and multifactorial nature of Alzheimer's disease (AD) requires the development of compounds able to hit different pathophysiological targets, such as cholinergic dysfunction, deposits of amyloid beta (Ab) peptide and metal dyshomeostasis. In order to continue the search for new anti AD drugs, a design strategy was once more followed based on repositioning donepezil (DNP) drug, by ortho attaching a benzylpiperidine mimetic of DNP moiety to a hydroxyphenyl benzimidazole (BIM) chelating unit (compound 1) Herein, compound 1 and a positional isomer 2 are compared in terms of their potential multiple properties: both present good acetylcholinesterase (AChE) inhibition (low mmolar range) and are moderate/good inhibitors of Ab self and Cu mediated aggregation, the inhibition process being mainly due to ligand intercalation between the b sheets of the fibrils; compound 1 has a higher chelating capacity towards Cu2+ and Zn2+ (pCu 14.3, pZn 6.4, pH 7.4, CL/CM 10, CM 10 6 M) than 2 (pCu 10.7, pZn 6.3) attributed to its ability to establish a tridentate (N,O,O) coordination to the metal ion. Both compounds are eligible as drug candidates for oral administration but compound 1 shows improved neuroprotective role by completely preventing Ab induced cell toxicity.
author_names: Marina Costa

Romane Josselin

Diana F Silva

Sandra M Cardoso

Nora Veronika May

Silvia Chaves

M Amelia Santos
title: Donepezil based hybrids as multifunctional anti Alzheimer's disease chelating agents: Effect of positional isomerization.
venue: Journal of inorganic biochemistry
year: 2020

abstract: The methods of quartz crystal microbalance, atomic force microscopy (AFM) scanning electron microscopy (SEM) Fourier transform IR spectroscopy, and X ray structural microanalysis were is used to show that adsorption of vinyl silane on an aluminum surface from an aqueous solution results in formation of a uniform, self organizing protective vinyl siloxane nanolayer covalently bound with surface metal groups. Its thickness can be controlled by variation of application conditions. The effect of a vinyl siloxane nanolayer on dissolution of aluminum is studied in chloride containing solutions. It is found that an ordered vinyl siloxane nanolayer with a thickness of up to 5 molecular layers causes efficient inhibition of uniform and local corrosion of aluminum. It is shown that the vinyl siloxane nanolayer is preserved on the surface of aluminum after 10 days of corrosion tests, which indicates its stability at exposure to water and corrosive components.
author_names: Maxim Petrunin

L B Maksaeva

Tatiana Yurasova

E V Terekhova

M A Maleeva

A A Shcherbina

V A Kotenev

E N Kablov

Aslan Yu Tsivadze
title: The effect of self organizing vinyl siloxane nanolayers on the corrosion behavior of aluminum in neutral chloride containing solutions
venue: Protection of Metals and Physical Chemistry of Surfaces
year: 2014

abstract: To better understand how renal Na( reabsorption is altered by heavy metal poisoning, we examined the effects of several divalent heavy metal ions (Zn(2+ Ni(2+ Cu(2+ Pb(2+ Cd(2+ and Hg(2+ on the activity of single epithelial Na( channels (ENaC) in a renal epithelial cell line (A6) None of the cations changed the single channel conductance. However, ENaC activity [measured as the number of channels (N) x open probability (P(o) was decreased by Cd(2+ and Hg(2+ and increased by Cu(2+ Zn(2+ and Ni(2+ but was not changed by Pb(2+ Of the cations that induced an increase in Na( channel function, Zn(2+ increased N, Ni(2+ increased P(o) and Cu(2+ increased both. The cysteine modification reagent [2 (trimethylammonium)ethyl]methanethiosulfonate bromide also increased N, whereas diethylpyrocarbonate, which covalently modifies histidine residues, affected neither P(o) nor N. Cu(2+ increased N and stimulated P(o) by reducing Na( self inhibition. Furthermore, we observed that ENaC activity is slightly voltage dependent and that the voltage dependence of ENaC is insensitive to extracellular Na( concentration; however, apical application of Ni(2+ or diethylpyrocarbonate reduced the channel voltage dependence. Thus the voltage sensor of Xenopus ENaC is different from that of typical voltage gated channels, since voltage appears to be sensed by histidine residues in the extracellular loops of ENaC, rather than by charged amino acids in a transmembrane domain.
author_names: Ling Yu

Douglas C Eaton

My N Helms
title: Effect of divalent heavy metals on epithelial Na+ channels in A6 cells.
venue: American journal of physiology. Renal physiology
year: 2007

abstract: A series of novel chalcone derivatives was designed, synthesized and evaluated as multifunctional agents for the treatment of AD. Among of these synthesized compounds, compound TM 2 was a selective BuChE inhibitor (IC50 2.6 mM) and selective MAO B inhibitor (IC50 5.3 mM) which were supported by docking study. Compound TM 2 also showed good antioxidant activity, and was a selective metal chelator, as well as a neuroprotectant. Moreover, compound TM 2 could significantly inhibit self induced and Cu2+ induced Ab1 42 aggregation with 70.2% and 80.7% inhibition rate, respectively, and could disaggregate Cu2+ induced Ab1 42 aggregation (73.5% the further TEM images observed provided rational explanation. Besides, compound TM 2 displayed good PAMPA BBB permeability and conformed to the Lipinski's rule of five. Further, compound TM 2 presented precognitive effect on scopolamine induced memory impairment in vivo assay. Therefore, compound TM 2 might be a promising multifunctional hit compound for the treatment of AD, and the further structure optimization are in progress.
author_names: Zhipei Sang

Keren Wang

Pengfei Zhang

Jian Shi

Wenmin Liu

Zhenghuai Tan
title: Design, synthesis, in silico and biological evaluation of novel chalcone derivatives as multi function agents for the treatment of Alzheimer's disease.
venue: European journal of medicinal chemistry
year: 2019

abstract: In this work, we designed polysaccharide metal complex of dopamine modified pectin linking ruthenium compound, which exhibited a certain inhibition specificity to human renal cell adenocarcinoma cell line 786 O. The chemical structure and physical properties of the polysaccharide metal complex were well characterized by multiple analysis methods. The multi spectral results revealed that pectin dopamine have been successfully coordinated by ruthenium complex to form nano conjugates, which self assembled into relatively regular nanospheres of approximately 200 nm. The polysaccharide metal complex has more amorphous and less viscosity than pectin, and cannot withstand as much strain as the pectin and pectin dopamine systems. Pectin dopamine can decrease the toxicity effect of Ru complex in normal cell line such as human normal renal epithelial cell line 293A.
author_names: Jiajing Diao

Feng Bai

Ying Wang

Qianqian Han

Xi Xu

Hongmei Zhang

Qiang Luo

Yanqing Wang
title: Engineering of pectin dopamine nano conjugates for carrying ruthenium complex: A potential tool for biomedical applications.
venue: Journal of inorganic biochemistry
year: 2019

abstract: A series of scutellarein O alkylamine derivatives were designed, synthesized and tested as multifunctional agents for the treatment of Alzheimer's disease (AD) The results showed that most of these compounds exhibited good multifunctional activities. Among them, compound 16d demonstrated significant metal chelating properties, moderate acetylcholinesterase (AChE) inhibitory and anti oxidative activity, and excellent inhibitory effects on self induced Ab(1 42) aggregation, Cu(2+ induced Ab(1 42) aggregation, human AChE induced Ab(1 40) aggregation and disassembled Cu(2+ induced aggregation of the well structured Ab(1 42) fibrils. Both kinetic analysis of AChE inhibition and molecular modeling study suggested that 16d binds simultaneously to the catalytic active site and peripheral anionic site of AChE. Moreover, compound 16d showed a good protective effect against H2O2 induced PC12 cell injury, with low toxicity in SH SY5Y cells. Furthermore, the step down passive avoidance test showed this compound significantly reversed scopolamine induced memory deficit in mice. Thus, 16d was shown to be an interesting multifunctional lead compound worthy of further study.
author_names: Zhipei Sang

Xiaoming Qiang

Yan Li

Wen Yuan

Q Liu

Yikun Shi

Wei Ang

Youfu Luo

Zhenghuai Tan

Yong Deng
title: Design, synthesis and evaluation of scutellarein O alkylamines as multifunctional agents for the treatment of Alzheimer's disease.
venue: European journal of medicinal chemistry
year: 2015

abstract: We use hydrodynamical simulations from the OverWhelmingly Large Simulations (OWLS) project to investigate the dependence of the physical properties of galaxy populations at redshift 2 on metal line cooling and feedback from star formation and active galactic nuclei (AGN) We find that if the sub grid feedback from star formation is implemented kinetically, the feedback is only efficient if the initial wind velocity exceeds a critical value. This critical velocity increases with galaxy mass and also if metal line cooling is included. This suggests that radiative losses quench the winds if their initial velocity is too low. If the feedback is efficient, then the star formation rate is inversely proportional to the amount of energy injected per unit stellar mass formed (which is proportional to the initial mass loading for a fixed wind velocity) This can be understood if the star formation is self regulating, i.e. if the star formation rate (and thus the gas fraction) increases until the outflow rate balances the inflow rate. Feedback from AGN is efficient at high masses, while increasing the initial wind velocity with gas pressure or halo mass allows one to generate galaxy wide outflows at all masses. Matching the observed galaxy mass function requires efficient feedback. In particular, the predicted faint end slope is too steep unless we resort to highly mass loaded winds for low mass objects. Such efficient feedback from low mass galaxies (M* 1010 M) also reduces the discrepancy with the observed specific star formation rates, which are higher than predicted unless the feedback transitions from highly efficient to inefficient just below M* 5 x 109 M.
author_names: Marcel Richard Haas

Joop Schaye

Craig M Booth

Claudio Dalla Vecchia

Volker Springel

Tom Theuns

Robert P C Wiersma Rutgers University

Leiden Observatory

University of Chicago

Kavli Institute for Cosmological Physics

Enrico Fermi Institute

Heidelberger Institut fur Theoretische Studien

Heidelberg Northwestern University

University of Durham

University of Antwerp
title: Physical properties of simulated galaxy populations at z=2 I. Effect of metal line cooling and feedback from star formation and AGN
year: 2013

abstract: Abstract For the first time, Feldspar (F) nanocontainer, which is a group of rock forming tectosilicate minerals with the chemical composition of KAlSi3O8 NaAlSi3O8 CaAl2Si2O8, was used for the construction of an epoxy composite coating with superior barrier and self healing anti corrosion performance. Feldspar (F) based nanocontainer with robust corrosion inhibitive activity was fabricated through the encapsulation of zinc cations as a cathodic inhibitor. It was understood from the electrochemical measurements that in the saline solution including F/Zn extract the metal corrosion was significantly retarded (by protection efficiency of 73% due to the inhibitor release activity of the F/Zn container and protective film generation on the metal surface. The inductively coupled plasma (ICP) analysis results confirmed the Zn2+ cations (5.33 mg/L) release in the chloride solution from the F/Zn container. EIS test results evidenced the significant effect of the F/Zn in the epoxy ester composite coating barrier and self healing anti corrosion functions in the intact and scratched forms. In the presence of F/Zn an improvement in the charge transfer resistance (about 83% of the scratched coating was observed, indicating the active self healing inhibition effect of the F/Zn nanocarrier. By incorporation of the F/Zn particles into the epoxy ester coating the E' (at 30 degC) glass transition temperature (Tg) stress, strain and energy at break were significantly enhanced. These results proved that not only the corrosion protection properties but also the mechanical properties of the epoxy ester coating were excellently improved in the presence of F/Zn nanocarrier.
author_names: M M Davoodi

Esmaeil Ghasemi

Bahram Ramezanzadeh

Mohammad Mahdavian
title: Designing a zinc encapsulated Feldspar as a unique rock forming tectosilicate nanocontainer in the epoxy coating; improving the robust barrier and self healing anti corrosion properties
year: 2020

abstract: Electroless deposition (ELD) is widely used in industry to deposit metals because it is inexpensive and compatible with organic materials. The deposition rate and deposited film properties critically depend on the reducing agent, complexing agent, and bath pH and temperature as well as bath additives. We have investigated the role of ethanolamine additives in the ELD of copper using the reducing agent dimethylamine borane on CH3 and OH terminated self assembled monolayers (SAMs) adsorbed on gold. Three additives were studied: ethanolamine (EOA) diethanolamine (DEOA) and triethanolamine (TEOA) Both the chemical identity and concentration of the ethanolamine significantly affect the deposition process. We show that the Cu deposition rate is faster on CH3 terminated surfaces than on OH terminated SAMs because of the stronger interaction of the ethanolamines with the hydroxyl terminal group. In contrast to physical vapor deposition and other ELD processes, Cu deposits atop methyl terminated SAMs using TEOA. However, using EOA and DEOA, copper penetrates through CH3 terminated SAMs to the Au/S interface. For OH terminated SAMs, copper is observed to penetrate through the SAM for all ethanolamines investigated. The amount of copper penetration through the SAM to the Au/S interface increases with ethanolamine concentration. These effects are attributed to an adsorption inhibition mechanism and differences in the chelation of Cu2+ in the deposition bath.
author_names: Ashley A Ellsworth

Amy V Walker
title: Effect of Ethanolamines on the Electroless Deposition of Copper on Functionalized Organic Surfaces.
venue: Langmuir the ACS journal of surfaces and colloids
year: 2018