ChemInform Abstract: Chemical Modifications of the Aliphatic Bridge in Ansamycins. Synthesis and Activity of 18,19-Dihydrorifamycin S.

ChemInform ◽  
1990 ◽  
Vol 21 (17) ◽  
Author(s):  
A. D. BIANCO ◽  
M. BRUFANI ◽  
D. CAPITANI ◽  
L. CELLAI ◽  
M. GUISO ◽  
...  
Keyword(s):  
Chemical Modifications ◽  
Aliphatic Bridge

scholarly journals Chemical modifications of the aliphatic bridge of ansamycins. 3. Synthesis and activity of 21-epi-rifamycin S.

1985 ◽  
Vol 38 (10) ◽  
pp. 1359-1362 ◽  
Author(s):  
M. BRUFANI ◽  
L. CELLAI ◽  
L. COZZELLA ◽  
M. FEDERICI
Keyword(s):  
Chemical Modifications ◽  
Aliphatic Bridge

scholarly journals Chemical modifications of the aliphatic bridge of ansamycins. 2. Synthesis and activity of 23-epi-25-deacetylrifamycin S.

1985 ◽  
Vol 38 (2) ◽  
pp. 259-262 ◽  
Author(s):  
M. BRUFANI ◽  
G. CECCHINI ◽  
L. CELLAI ◽  
M. FEDERICI ◽  
M. GUISO ◽  
...  
Keyword(s):  
Chemical Modifications ◽  
Aliphatic Bridge

Degradation Analysis of Thick Film Chip Resistors

2009 ◽  
Author(s):  
Bhanu Sood ◽  
Diganta Das ◽  
Michael H. Azarian ◽  
Michael Pecht
Keyword(s):  
Thick Film ◽  
Printed Circuit Board ◽  
Negative Resistance ◽  
Circuit Board ◽  
High Humidity ◽  
Circuit Boards ◽  
Chemical Modifications ◽  
Current Leakage ◽  
Printed Circuit ◽  
Degradation Analysis

Abstract Negative resistance drift in thick film chip resistors in high temperature and high humidity application conditions was investigated. This paper reports on the investigation of possible causes including formation of current leakage paths on the printed circuit board, delamination between the resistor protective coating and laser trim, and the possibility of silver migration or copper dendrite formation. Analysis was performed on a set of circuit boards exhibiting failures due to this phenomenon. Electrical tests after mechanical and chemical modifications showed that the drift was most likely caused by moisture ingress that created a conductive path across the laser trim.

scholarly journals Rational Generation of Lasso Peptides Based on Biosynthetic Gene Mutations and Site-Selective Chemical Modifications

2021 ◽  
Author(s):  
Tan Liu ◽  
Xiaojie Ma ◽  
Jiahui Yu ◽  
Wensheng Yang ◽  
guiyang wang ◽  
...  
Keyword(s):  
Natural Products ◽  
Gene Mutations ◽  
Proteolytic Degradation ◽  
Biosynthetic Gene ◽  
Chemical Modifications ◽  
Lasso Peptides ◽  
Selective Chemical ◽  
Site Selective

Lasso peptides are a unique family of natural products whose structures feature a specific threaded fold, which confers these peptides the resistance to thermal and proteolytic degradation. This stability gives...

Impact of chemistry on the preparation and post-modification of multilayered hollow microcapsules

2021 ◽  
Author(s):  
Angana Borbora ◽  
Uttam Manna
Keyword(s):  
Chemical Interactions ◽  
Chemical Modifications ◽  
Post Modification

Different chemical interactions/bonding allowed LbL deposition of selected constituents, and further post-chemical modifications of chemically reactive multilayered microcapsules allowed to associate desired chemical functionalities.

scholarly journals Thiophene-Based Trimers and Their Bioapplications: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1977
Author(s):  
Lorenzo Vallan ◽  
Emin Istif ◽  
I. Jénnifer Gómez ◽  
Nuria Alegret ◽  
Daniele Mantione
Keyword(s):  
Optical Properties ◽  
Medical Research ◽  
Turning Point ◽  
State Of The Art ◽  
Thiophene Ring ◽  
Functional Polymers ◽  
Direct Application ◽  
Synthetic Methods ◽  
Scientific Interest ◽  
Chemical Modifications

Certainly, the success of polythiophenes is due in the first place to their outstanding electronic properties and superior processability. Nevertheless, there are additional reasons that contribute to arouse the scientific interest around these materials. Among these, the large variety of chemical modifications that is possible to perform on the thiophene ring is a precious aspect. In particular, a turning point was marked by the diffusion of synthetic strategies for the preparation of terthiophenes: the vast richness of approaches today available for the easy customization of these structures allows the finetuning of their chemical, physical, and optical properties. Therefore, terthiophene derivatives have become an extremely versatile class of compounds both for direct application or for the preparation of electronic functional polymers. Moreover, their biocompatibility and ease of functionalization make them appealing for biology and medical research, as it testifies to the blossoming of studies in these fields in which they are involved. It is thus with the willingness to guide the reader through all the possibilities offered by these structures that this review elucidates the synthetic methods and describes the full chemical variety of terthiophenes and their derivatives. In the final part, an in-depth presentation of their numerous bioapplications intends to provide a complete picture of the state of the art.

scholarly journals Antiviral Activity of Carrageenans and Processing Implications

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 437
Author(s):  
Milena Álvarez-Viñas ◽  
Sandra Souto ◽  
Noelia Flórez-Fernández ◽  
Maria Dolores Torres ◽  
Isabel Bandín ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Antiviral Activity ◽  
Drug Delivery Systems ◽  
Biological Properties ◽  
Red Seaweed ◽  
Processing Conditions ◽  
Chemical Modifications ◽  
Viral Attachment ◽  
Extraction Stage ◽  
Composition Structure

Carrageenan and carrageenan oligosaccharides are red seaweed sulfated carbohydrates with well-known antiviral properties, mainly through the blocking of the viral attachment stage. They also exhibit other interesting biological properties and can be used to prepare different drug delivery systems for controlled administration. The most active forms are λ-, ι-, and κ-carrageenans, the degree and sulfation position being determined in their properties. They can be obtained from sustainable worldwide available resources and the influence of manufacturing on composition, structure, and antiviral properties should be considered. This review presents a survey of the antiviral properties of carrageenan in relation to the processing conditions, particularly those assisted by intensification technologies during the extraction stage, and discusses the possibility of further chemical modifications.

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