Recent Advances in Glass Transitions in Polymers

1970 ◽  
Vol 43 (1) ◽  
pp. 156-170 ◽  
Author(s):  
A. Eisenberg ◽  
M. Shen
Keyword(s):  
Glass Transition ◽  
Present Article ◽  
Progress Report ◽  
Previous Article ◽  
Glass Transitions ◽  
The Past ◽  
Recent Advances ◽  
Made In

Abstract Since the publication of our review “Glass Transition in Polymers” in 1966, a number of interesting advances have been made in this field. The present article is intended to be an addendum to this review, reporting the progress that has been made by various workers during the past three years. In addition, a number of topics were not covered in the previous article due to the relatively incomplete understanding at that time. These will now be discussed. This is not because these topics are at present fully understood. Rather, we hope it will serve as a progress report to stimulate further interest in areas where further work is needed. The numbering systems and notations in this paper will follow those in the previous article for the sake of continuity.

A Progress Report on the Quest to Establish a Cybersickness Dose Value

2002 ◽  
Vol 46 (26) ◽  
pp. 2119-2123 ◽  
Author(s):  
Wei Chen ◽  
S.L. Yuen ◽  
R.H.Y. So
Keyword(s):  
Linear Relationship ◽  
Motion Sickness ◽  
Progress Report ◽  
Simulation Studies ◽  
Current Effort ◽  
British Standard ◽  
The Past ◽  
Frequency Weighting ◽  
Made In

This paper summarizes the progress made in the quest to establish a Cybersickness Dose Value (CSDV). The Motion Sickness Dose Value (MSDV), reported in the British Standard BS6841, has been used to predict the severity of seasickness since 1987. In 1999, the authors of this paper proposed a CSDV formulation with a structure similar to that of the MSDV (So, 1999). Since then, several experiments and simulation studies have been conducted to modify and develop the proposed CSDV formula. In particular, progress has been made in (i) the methods to measure CSDV, (ii) the determination of a frequency weighting curve to equalize the non-linear relationship between the navigation velocity and levels of cybersickness, and (iii) the detailed formulation of CSDV. This paper summarizes the past progress and reports on the current effort in developing a CSDV.

scholarly journals Recent Advances in Palladium-Catalyzed Isocyanide Insertions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4906
Author(s):  
Jurriën W. Collet ◽  
Thomas R. Roose ◽  
Bram Weijers ◽  
Bert U. W. Maes ◽  
Eelco Ruijter ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Building Blocks ◽  
Insertion Reactions ◽  
Chemical Reagents ◽  
The Past ◽  
Recent Advances ◽  
Recent Developments ◽  
Palladium Catalyzed ◽  
Made In ◽  
Rapid Incorporation

Isocyanides have long been known as versatile chemical reagents in organic synthesis. Their ambivalent nature also allows them to function as a CO-substitute in palladium-catalyzed cross couplings. Over the past decades, isocyanides have emerged as practical and versatile C1 building blocks, whose inherent N-substitution allows for the rapid incorporation of nitrogeneous fragments in a wide variety of products. Recent developments in palladium catalyzed isocyanide insertion reactions have significantly expanded the scope and applicability of these imidoylative cross-couplings. This review highlights the advances made in this field over the past eight years.

scholarly journals Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

2021 ◽  
Vol 17 ◽  
pp. 2462-2476
Author(s):  
Yi Liu ◽  
Puying Luo ◽  
Yang Fu ◽  
Tianxin Hao ◽  
Xuan Liu ◽  
...  
Keyword(s):  
Reaction Mechanisms ◽  
Structural Motifs ◽  
Pyrrole Derivatives ◽  
The Past ◽  
Recent Advances ◽  
Functionalized Pyridine ◽  
Great Progress ◽  
Made In

Great progress has been made in the tandem annulation of enynes in the past few years. This review only presents the corresponding reactions of 1,3-enyne structural motifs to provide the functionalized pyridine and pyrrole derivatives. The functionalization reactions cover iodination, bromination, trifluoromethylation, azidation, carbonylation, arylation, alkylation, selenylation, sulfenylation, amidation, esterification, and hydroxylation. We also briefly introduce the applications of the products and the reaction mechanisms for the synthesis of corresponding N-heterocycles.

scholarly journals Recent advances in the synthesis of α-amino ketones

2021 ◽  
Author(s):  
Lewis A. T. Allen ◽  
Robert-Cristian Raclea ◽  
Philipp Natho ◽  
Philip J. Parsons
Keyword(s):  
Functional Group ◽  
Amino Ketone ◽  
Product Substitution ◽  
The Past ◽  
Recent Advances ◽  
Extended Discussion ◽  
Made In

This review on α-amino ketone synthesis collates and evaluates developments made in this area over the past decade, with an extended discussion on functional group compatibility, resultant product substitution patterns, and medicinal applications.

scholarly journals Recent Advances in Enantioselective Photochemical Reactions of Stabilized Diazo Compounds

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3191 ◽  
Author(s):  
Ting-Bi Hua ◽  
Qing-Qing Yang ◽  
You-Quan Zou
Keyword(s):  
Photochemical Reactions ◽  
Diazo Compounds ◽  
Reaction Type ◽  
The Past ◽  
Recent Advances ◽  
Wide Range ◽  
Metal Carbenoids ◽  
Metal Catalyzed ◽  
Made In

Diazo compounds have proven to be a useful class of carbenes or metal carbenoids sources under thermal, photochemical, or metal-catalyzed conditions, which can subsequently undergo a wide range of synthetically important transformations. Recently, asymmetric photocatalysis has provoked increasing research interests, and great advances have been made in this discipline towards the synthesis of optically enriched compounds. In this context, the past two decades have been the most productive period in the developments of enantioselective photochemical reactions of diazo compounds due to a better understanding of the reactivities of diazo compounds and the emergence of new catalytic modes, as well as easier access to and treatment of stabilized diazo compounds. This review highlights these impressive achievements according to the reaction type, and the general mechanisms and stereochemical inductions are briefly discussed as well.

The Plays of Bhāsa

1921 ◽  
Vol 53 (3) ◽  
pp. 367-382
Author(s):  
A. Banerji-Śāstrī
Keyword(s):  
Present Article ◽  
General Trend ◽  
Fifth Century ◽  
The Past ◽  
Sanskrit Series ◽  
Made In ◽  
The Way

Towards the beginning of the fifth century a.d. Kālidāsa made his début with an apology for his temerity in addressing an audience accustomed to such old, wellestablished authors as “Bhāsa and others”. After the lapse of fifteen centuries Kālidāsa has held his own, while Bhāsa is practically forgotten. The reason is not the decisive verdict of Time, but the unfortunate loss of his works. But lately came a surprise. In 1912 Gaṇapati Śāstrī discovered and published thirteen dramas in the Trivandrum Sanskrit Series, and claimed them as Bhāsa's. For the past eight years Orientalists have been considering this claim, the general trend of opinion being unfavourable. The present article proposes to supplement the progress already made in the investigation of this question, and to point out the facts practically settled, thus paving the way for further research.

scholarly journals The Smell of Synthetic Biology: Engineering Strategies for Aroma Compound Production in Yeast

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 54 ◽  
Author(s):  
Niël van Wyk ◽  
Heinrich Kroukamp ◽  
Isak Pretorius
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Recombinant Proteins ◽  
Aroma Compounds ◽  
Aroma Compound ◽  
Biochemical Pathways ◽  
The Past ◽  
Recent Advances ◽  
New Directions ◽  
The Given ◽  
Made In

Yeast—especially Saccharomyces cerevisiae—have long been a preferred workhorse for the production of numerous recombinant proteins and other metabolites. S. cerevisiae is a noteworthy aroma compound producer and has also been exploited to produce foreign bioflavour compounds. In the past few years, important strides have been made in unlocking the key elements in the biochemical pathways involved in the production of many aroma compounds. The expression of these biochemical pathways in yeast often involves the manipulation of the host strain to direct the flux towards certain precursors needed for the production of the given aroma compound. This review highlights recent advances in the bioengineering of yeast—including S. cerevisiae—to produce aroma compounds and bioflavours. To capitalise on recent advances in synthetic yeast genomics, this review presents yeast as a significant producer of bioflavours in a fresh context and proposes new directions for combining engineering and biology principles to improve the yield of targeted aroma compounds.

Tertiary Enamides: Versatile and Available Substrates in Synthetic Chemistry

2019 ◽  
Vol 16 (1) ◽  
pp. 70-97 ◽  
Author(s):  
Xiaohua Cai ◽  
Mengzhi Yang ◽  
Hui Guo
Keyword(s):  
Chemical Reaction ◽  
Coupling Reaction ◽  
Building Blocks ◽  
Synthetic Chemistry ◽  
The Past ◽  
Recent Advances ◽  
Complex Building ◽  
Group A ◽  
Unique Stability ◽  
Made In

Background: Enamines and their variant enamides as powerful and versatile synthons have attracted great attention in synthetic chemistry. Enamides display unique stability and reduce enaminic reactivity in view of the electron-withdrawing effect of N-acyl group. A great deal of satisfactory achievements in the synthesis and application of enamides has been made in recent years. Especially, tertiary enamides without N-H bond regarded as low reactivity of compounds in the past can act as excellent nucleophiles to react with electrophiles for the construction of various nitrous molecules. </P><P> Objective: This review focuses on recent advances on tertiary enamides in the synthetic strategies and applications including addition, coupling reaction, functionalization and electro- or photo-chemical reaction. Conclusion: Tertiary enamides as electron-deficient nucleophiles display a satisfactory balance between stability and reactivity to offer multiple opportunities for the construction of various functionalized nitrogencontaining compounds. Further exploration of the reactive mechanisms involved tertiary enamides and the development of novel and efficient transformations to generate ever more complex building blocks starting from tertiary enamides are particularly worth pursuing.

N,N-Dimethylformamide (DMF): An Inexpensive and Attractive Reactant

2021 ◽  
Vol 25 ◽  
Author(s):  
Xiao-hua CAI ◽  
Hui GUO
Keyword(s):  
Building Block ◽  
Polar Solvent ◽  
Raw Material ◽  
Synthetic Chemistry ◽  
The Past ◽  
Recent Advances ◽  
Synthetic Reactions ◽  
Simple Atom ◽  
Made In ◽  
Versatile Reagent

: The development of simple, atom-economical, and sustainable methodologies for the construction of various functional molecules from easily available substrates has been of great interest in synthetic chemistry. N,N-dimethylformamide (DMF) is an inexpensive, abundant solvent and industrial raw material. It is considered as an effective polar solvent and a versatile reagent in synthetic transformations. During the past few decades, many significant and attractive achievements have been made in the fields of DMF as a reactant. The mini-review will mainly summarize recent advances in the applicants of DMF as a multipurpose building block in synthetic reactions.

Recent Advances in Nutrition

PEDIATRICS ◽  
1951 ◽  
Vol 8 (5) ◽  
pp. 752-752
Keyword(s):  
Research Team ◽  
University Of Kansas ◽  
University Of Chicago ◽  
The Past ◽  
Recent Advances ◽  
The University ◽  
Made In

This book is divided into 3 portions corresponding to the 3 Porter Lectures given by Dr. Cannon at the University of Kansas. The work described was done by a research team at the University of Chicago. In an interesting and easily understood manner the author discusses new advances made in the field of nutrition over the past 2 decades. The first portion of the monograph is devoted to a brief discussion of earlier data gathered by other investigative groups which contributed to the present work.

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