ChemInform Abstract: Alternative Synthetic Methods Through New Developments in Catalysis by Gold

ChemInform ◽  
2008 ◽  
Vol 39 (48) ◽  
Author(s):  
Antonio Arcadi
Keyword(s):  
Synthetic Methods ◽  
New Developments

scholarly journals General sociolinguistics, social semiotics and semiotics of culture – ex pluribus unum? Forty years after Language as Social Semiotic

2020 ◽  
Vol 47 (3/4) ◽  
Author(s):  
Suren Zolyan
Keyword(s):  
Social Sciences ◽  
Goal Setting ◽  
Synthetic Methods ◽  
Social Semiotics ◽  
Dynamic Approach ◽  
Functional Characteristics ◽  
New Developments ◽  
Meaning Production ◽  
Linguistic Structures

The birth of social semiotics is usually associated with the publication of Michael Halliday’s book Language as Social Semiotic (1978). We try to draw attention to possible new developments in social semiotics, which still remain a potential transdisciplinary project for social sciences. In order to do this, we address the interrelation between sociolinguistics, social semiotics and the semiotics of culture. All of these describe mechanisms of meaning production and translation beyond linguistic structures. The differentiation between these workings is based on a distinc tion between various aspects of meaning production and communication and functional characteristics of goal setting. The complexity of these processes legitimates the complexity of methodology used to describe them. Interconnection between different domains and aspects may create synthetic methods based on the dynamic approach to meaning production and transmission.

scholarly journals Biomimetic molecular design tools that learn, evolve, and adapt

2017 ◽  
Vol 13 ◽  
pp. 1288-1302 ◽  
Author(s):  
David A Winkler
Keyword(s):  
Molecular Design ◽  
Optimization Methods ◽  
Synthetic Methods ◽  
Biological Processes ◽  
New Developments ◽  
Design And Optimization ◽  
Bioactive Natural Products ◽  
Unit Operations ◽  
S Curve ◽  
Pass Through

A dominant hallmark of living systems is their ability to adapt to changes in the environment by learning and evolving. Nature does this so superbly that intensive research efforts are now attempting to mimic biological processes. Initially this biomimicry involved developing synthetic methods to generate complex bioactive natural products. Recent work is attempting to understand how molecular machines operate so their principles can be copied, and learning how to employ biomimetic evolution and learning methods to solve complex problems in science, medicine and engineering. Automation, robotics, artificial intelligence, and evolutionary algorithms are now converging to generate what might broadly be called in silico-based adaptive evolution of materials. These methods are being applied to organic chemistry to systematize reactions, create synthesis robots to carry out unit operations, and to devise closed loop flow self-optimizing chemical synthesis systems. Most scientific innovations and technologies pass through the well-known “S curve”, with slow beginning, an almost exponential growth in capability, and a stable applications period. Adaptive, evolving, machine learning-based molecular design and optimization methods are approaching the period of very rapid growth and their impact is already being described as potentially disruptive. This paper describes new developments in biomimetic adaptive, evolving, learning computational molecular design methods and their potential impacts in chemistry, engineering, and medicine.

scholarly journals A Review of the Pharmacological Activities and Recent Synthetic Advances of γ-Butyrolactones

2021 ◽  
Vol 22 (5) ◽  
pp. 2769
Author(s):  
Joonseong Hur ◽  
Jaebong Jang ◽  
Jaehoon Sim
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Small Molecules ◽  
Biologically Active ◽  
Synthetic Methods ◽  
Pharmacological Activities ◽  
New Developments ◽  
The Past ◽  
Privileged Structures ◽  
Significant Attention

γ-Butyrolactone, a five-membered lactone moiety, is one of the privileged structures of diverse natural products and biologically active small molecules. Because of their broad spectrum of biological and pharmacological activities, synthetic methods for γ-butyrolactones have received significant attention from synthetic and medicinal chemists for decades. Recently, new developments and improvements in traditional methods have been reported by considering synthetic efficiency, feasibility, and green chemistry. In this review, the pharmacological activities of natural and synthetic γ-butyrolactones are described, including their structures and bioassay methods. Mainly, we summarize recent advances, occurring during the past decade, in the construction of γ-butyrolactone classified based on the bond formation in γ-butyrolactone between (i) C5-O1 bond, (ii) C4-C5 and C2-O1 bonds, (iii) C3-C4 and C2-O1 bonds, (iv) C3-C4 and C5-O1 bonds, (v) C2-C3 and C2-O1 bonds, (vi) C3-C4 bond, and (vii) C2-O1 bond. In addition, the application to the total synthesis of natural products bearing γ-butyrolactone scaffolds is described.

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

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