Development of a Novel Method to Study the Rate-Determining Step during Protein Regeneration:  Application to the Oxidative Folding of RNase A at Low Temperature Reveals BPTI-like Kinetic Traps

2001 ◽  
Vol 123 (12) ◽  
pp. 2909-2910 ◽  
Author(s):  
Mahesh Narayan ◽  
Ervin Welker ◽  
Harold A. Scheraga
Keyword(s):  
Low Temperature ◽  
Rnase A ◽  
Oxidative Folding ◽  
Rate Determining Step ◽  
Novel Method ◽  
Kinetic Traps

Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dft Calculations ◽  
Bond Activation ◽  
Mild Conditions ◽  
Selective Transformation ◽  
Rate Determining Step ◽  
Highly Active ◽  
Harsh Conditions ◽  
Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

scholarly journals Thermo-voltage measurements of atomic contacts at low temperature

2016 ◽  
Vol 7 ◽  
pp. 767-775 ◽  
Author(s):  
Ayelet Ofarim ◽  
Bastian Kopp ◽  
Thomas Möller ◽  
León Martin ◽  
Johannes Boneberg ◽  
...  
Keyword(s):  
Finite Element ◽  
Low Temperature ◽  
Temperature Difference ◽  
Laser Heating ◽  
Laser Source ◽  
Break Junction ◽  
Resistance Change ◽  
Element Simulation ◽  
Novel Method

We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ) system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = −ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature.

scholarly journals Two new structured intermediates in the oxidative folding of RNase A

FEBS Letters ◽  
1999 ◽  
Vol 460 (3) ◽  
pp. 477-479 ◽  
Author(s):  
Ervin Welker ◽  
Mahesh Narayan ◽  
Michael J Volles ◽  
Harold A Scheraga
Keyword(s):  
Rnase A ◽  
Oxidative Folding

Low Temperature Fabrication and Surface Modification Methods for Fused Silica Micro- and Nanochannels

2014 ◽  
Vol 1659 ◽  
pp. 15-26
Author(s):  
Sumita Pennathur ◽  
Pete Crisalli
Keyword(s):  
Low Temperature ◽  
Surface Properties ◽  
Fused Silica ◽  
Microfluidic Channels ◽  
Metal Electrodes ◽  
Release Channel ◽  
Nanofluidic Channels ◽  
Novel Method ◽  
Electronic Sensing ◽  
Release Method

ABSTRACTElectrokinetic based micro- and nanofluidic technologies provide revolutionary opportunities to separate, identify and analyze biomolecular species. Key to fully harnessing the power of such systems is the development of a robust method for integrated electrodes as well as a thorough understanding of the influence of the electrokinetic surface properties with and without different surface modifications. In this work, we demonstrate a surface micromachined fabrication approach for integrated addressable metal electrodes within centimeter-long nanofluidic channels using a low-temperature, xenon diflouride dry-release method for novel biosensing applications, as well as recent results from a joint theoretical and experimental study of electrokinetic surface properties in nano- and microfluidic channels fabricated with fused silica. The main contribution of this fabrication process involves the addition of addressable electrodes to a novel dry-release channel fabrication method, produced at <300°C, to be used in nanofluidic electronic sensing of biomolecules. Finally, we also show a novel method with which to coat our channels with silane based chemistries. Certain modifications are observed to show improved resistance to non-specific adhesion of both small molecules and proteins, indicating their further use as compatible surfaces in micro- and nanofluidic applications.

Excellent Surface Passivation by Silicon Dioxide Grown with a Electrochemical Method

2011 ◽  
Vol 685 ◽  
pp. 48-54
Author(s):  
Jun Zhang ◽  
Wei Ming Lu ◽  
Chun Lan Zhou ◽  
Zhen Li Wen ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Silicon Dioxide ◽  
Electrochemical Method ◽  
Silicon Surface ◽  
Surface Passivation ◽  
Comparison Study ◽  
Initial Value ◽  
Effective Lifetime ◽  
Positive Voltage ◽  
Novel Method

A novel method to grow silicon dioxide layers for passivating the silicon surface is given more attention. SiO2was grown by applying a positive voltage across silicon wafers in a nitric acid solution at low temperature. After annealing in N2media at 900°C for 20min, excellent surface passivation was achieved. The maximum effective lifetime of the silicon arrived at 29.8μs and 29.75μs, which was three times the value of silicon without passivation. The effective lifetime of other types of silicon could be ten times the initial value without the silicon dioxide. A comparison study of the effect of the FGA, annealing at low temperature and annealing in N2or O2containing medium at high temperature were investigated.

Major Kinetic Traps for the Oxidative Folding of Leech Carboxypeptidase Inhibitor†

Biochemistry ◽  
2003 ◽  
Vol 42 (22) ◽  
pp. 6754-6761 ◽  
Author(s):  
Silvia Salamanca ◽  
Li ◽  
Josep Vendrell ◽  
Francesc X. Aviles ◽  
Jui-Yoa Chang
Keyword(s):  
Oxidative Folding ◽  
Carboxypeptidase Inhibitor ◽  
Kinetic Traps

Research on the Tribological Property of Synthetic Multilayer MoS2/FeS Film under Dry Condition

2011 ◽  
Vol 217-218 ◽  
pp. 1117-1122 ◽  
Author(s):  
Jia Jie Kang ◽  
Cheng Biao Wang ◽  
Hai Dou Wang ◽  
Bin Shi Xu ◽  
Jia Jun Liu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Low Temperature ◽  
Magnetron Sputtering ◽  
Tribological Property ◽  
Smooth Surface ◽  
Multilayer Film ◽  
Spherical Particles ◽  
Novel Method ◽  
1045 Steel ◽  
Ball On Disc

In this paper, we adopted a novel method, namely, magnetron sputtering + low temperature ion sulfurizing composite technology to prepare synthetic MoS2/FeS multilayer film. The obtained film has a quite smooth surface with plenty of spherical particles. The friction tests were carried out on a ball-on-disc tester under dry condition. During the whole test, the friction coefficient of the MoS2/FeS multilayer film was always lower than that of the original 1045 steel and FeS film. In addition, the wear scar depth of the MoS2/FeS multilayer film was also low. It is undoubtedly that the synthetic MoS2/FeS multilayer film possesses excellent friction-reducing and wear-resisting behaviors.

Ultraviolet Photodetector Based on ITO/MgO/ZnO Structure Grown by Hydrothermal Process

2018 ◽  
Vol 18 (12) ◽  
pp. 8399-8402
Author(s):  
Yunfeng Wu ◽  
Naisen Yu ◽  
Haiying Du ◽  
Dongping Liu ◽  
Hongwei Liang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Large Scale ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Ultraviolet Photodetector ◽  
Uv Detector ◽  
Uv Photodetector ◽  
Metal Insulator ◽  
Aqueous Method ◽  
Novel Method

A simple two-step aqueous method was employed to grow MgO nanostructures on ZnO/sapphire at low temperature. The obtained thin MgO nanostructures were uniformly distributed on the surface of ZnO layer and showed the sheet-like structures. Meanwhile, an ultraviolet (UV) photodetector based on ITO/MgO/ZnO structures was fabricated by simple way. The obtained UV detector showed excellent UV sensing properties. This novel method will greatly facilitate fabrication of large-scale metal-insulator-semiconductor with relatively low cost at remarkably low temperature.

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