Phosphodiester cleavage of diribonucleoside 3',3'-monophosphates: Rate acceleration by the 2'-hydroxyl and 2'-amino function, implications to ribozyme action

2005 ◽  
Author(s):  
Mikko Ora ◽  
Anu Kiviniemi ◽  
Tuomas Lönnberg ◽  
Sami Virtanen ◽  
Harri Lönnberg
Keyword(s):  
Rate Acceleration ◽  
Phosphodiester Cleavage

The Effect of Searching Versus Surfing on Cognitive and Emotional Responses to Online News

2009 ◽  
Vol 21 (2) ◽  
pp. 49-59 ◽  
Author(s):  
Kevin Wise ◽  
Hyo Jung Kim ◽  
Jeesum Kim
Keyword(s):  
Heart Rate ◽  
Skin Conductance ◽  
Skin Conductance Level ◽  
Emotional Responses ◽  
Online News ◽  
Self Report ◽  
Mixed Design ◽  
Information Need ◽  
News Stories ◽  
Rate Acceleration

A mixed-design experiment was conducted to explore differences between searching and surfing on cognitive and emotional responses to online news. Ninety-two participants read three unpleasant news stories from a website. Half of the participants acquired their stories by searching, meaning they had a previous information need in mind. The other half of the participants acquired their stories by surfing, with no previous information need in mind. Heart rate, skin conductance, and corrugator activation were collected as measures of resource allocation, motivational activation, and unpleasantness, respectively, while participants read each story. Self-report valence and recognition accuracy were also measured. Stories acquired by searching elicited greater heart rate acceleration, skin conductance level, and corrugator activation during reading. These stories were rated as more unpleasant, and their details were recognized more accurately than similar stories that were acquired by surfing. Implications of these results for understanding how people process online media are discussed.

Optimization of Perfusion Rate Acceleration is a Key Stage in Development of Highly Productive Perfusion Cultivation of CHO Cells

2016 ◽  
Vol 32 (4) ◽  
pp. 60-67
Author(s):  
A. N. MOROZOV ◽  
Z. V. ZAKHAROV ◽  
R. A. KOCHELABOV ◽  
D. V. TYUPA ◽  
A. V. ISERKAPOV ◽  
...  
Keyword(s):  
Cho Cells ◽  
Perfusion Rate ◽  
Rate Acceleration ◽  
Perfusion Cultivation

scholarly journals Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

2019 ◽  
Vol 15 ◽  
pp. 963-970 ◽  
Author(s):  
Sora Park ◽  
Jeung Gon Kim
Keyword(s):  
Ball Milling ◽  
Mechanochemical Synthesis ◽  
Polymeric Materials ◽  
Solvent Free ◽  
Energy Output ◽  
Polymerization Temperature ◽  
Mechanical Degradation ◽  
Trimethylene Carbonate ◽  
Rate Acceleration ◽  
Conventional Solution

Mechanochemical polymerization is a rapidly growing area and a number of polymeric materials can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation.

Copper-Catalyzed β-Boration of α,β-Unsaturated Carbonyl Compounds:  Rate Acceleration by Alcohol Additives†

2006 ◽  
Vol 8 (21) ◽  
pp. 4887-4889 ◽  
Author(s):  
Soungyun Mun ◽  
Ji-Eon Lee ◽  
Jaesook Yun
Keyword(s):  
Carbonyl Compounds ◽  
Rate Acceleration

The Synthesis and Catalytic Application of a New Class of Imprinted Silica

2003 ◽  
Vol 787 ◽  
Author(s):  
John D. Bass ◽  
Sandra L. Anderson ◽  
Alexander Katz
Keyword(s):  
Rational Design ◽  
Chemical Reactivity ◽  
Phenylboronic Acid ◽  
Coupling Reaction ◽  
Suzuki Coupling ◽  
Outer Sphere ◽  
Suzuki Coupling Reaction ◽  
New Class ◽  
Catalytic Application ◽  
Rate Acceleration

AbstractThe effect of chemical environment surrounding a synthetic heterogeneous catalyst active site is investigated using the hydrophilic imprinting of silica. Two model reaction systems have been used for this study: (i) Knoevenagel condensation of 3-nitrobenzaldehyde and malononitrile and (ii) Suzuki coupling of bromobenzene and phenylboronic acid. Using a catalyst in which isolated imprinted amines are surrounded by an acidic silanol-rich environment led to rate accelerations of over 120-fold relative to catalysts in which the amines are surrounded by a hydrophobic environment consisting of trimethylsilyl functional groups for system (i). This result parallels our previous study on the effect of the outer sphere composition on rate acceleration of Knoevenagel reactions using isophthalaldehyde as the aldehyde reactant. We also extended our method for the hydrophilic imprinting of bulk silica to organometallic systems, by successfully synthesizing a tethered palladium complex within the imprinted pocket. This material was used as an active catalyst for (ii). Our results show that a hydrophobic framework environment results in higher initial turnover frequencies than an acidic silanol-rich framework for the Suzuki coupling reaction of bromobenzene and phenylboronic acid, albeit with a lower overall effect than observed in the Knoevenagel system (i). Altogether, these results demonstrate the control of chemical reactivity via the rational design of the outer sphere using an imprinting approach.

Enhanced Wet Air Oxidation:  Synergistic Rate Acceleration upon Effluent Recirculation

2000 ◽  
Vol 39 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Matthew J. Birchmeier ◽  
Charles G. Hill ◽  
Carl J. Houtman ◽  
Rajai H. Atalla ◽  
Ira A. Weinstock
Keyword(s):  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Effluent Recirculation ◽  
Rate Acceleration
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