scholarly journals Chemical Bonding and Local Islamic Wisdom of Sasak Tribe, Lombok, West Nusa Tenggara

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Adi Fadli

A myriad of traditions underlie the local wisdom of Sasak tribe (the indigenous people in Lombok), namely tradisi merarik (wedding), nenarih (proposing), sorong serah ajikrame (dowry negotiation), langar, begawe (party) , banjar (the community body), begibung (eating together), berayan mangan (eating together), and nyongkolan (wedding parade). Such local customs in general entail the value of mutual concession or tolerance, compassion, dependency, social solidarity, sympathy, communal work for peace, and prosperity. The local wisdoms are strongly relevant to the theory of chemical bonding such as electrostatic stability and configuration, the positive and negative ions, theory of chemical bond formation, polar and nonpolar covalent, coordinate covalent bond, metal bonding, and intermolecular forces comprising hydrogen and Van der Waals bond. The interface and relevance of both are actualized in the religious and social values of Sasak Lombok tradition equivalent to the theory of chemical bonding. Therefore, this paper demonstrates that the theory of chemical bonding is strongly relevantly associated with the tradition of local Islamic wisdom of Sasak Lombok, West Nusa Tenggara.

1987 ◽  
Vol 52 (9) ◽  
pp. 2194-2203
Author(s):  
Miloslav Kučera ◽  
Dušan Kimmer ◽  
Karla Majerová ◽  
Josef Majer

In the reaction of dianions with poly(methyl methacrylate), only an insignificant amount of insoluble crosslinked product is obtained. If, however, the concentration of grafting dianions approaches that of ester groups, the amount of poly(methyl methacrylate) which may thus be crosslinked becomes quite significant. Dications, too, can bring about crosslinking of only an insignificant number of poly(methyl methacrylate) chains. Carboxylic groups in poly(acrylic acid) react with dianions and dications in an anhydrous medium similarly to ester groups. On the other hand, in the presence of a cocatalytic amount of water dications are more readily bound to carboxylic groups, forming a covalent bond. The relatively highest efficiency was observed in the bond formation between dication and the poly[styrene-alt-(maleic anhydride)], both in an anhydrous medium and in the presence of H2O.


2021 ◽  
Author(s):  
Bingqi Tong ◽  
Bridget Belcher ◽  
Daniel Nomura ◽  
Thomas Maimone

Electrophilic natural products have provided fertile ground for understanding how nature inhibits protein function using covalent bond formation. The fungal strain Gymnascella dankaliensis has provided an especially interesting collection of...


Author(s):  
Motofumi Osaki ◽  
Tomoko Sekine ◽  
Hiroyasu Yamaguchi ◽  
Yoshinori Takashima ◽  
Akira Harada

2020 ◽  
Author(s):  
Angus Voice ◽  
Gary Tresadern ◽  
Rebecca Twidale ◽  
Herman Van Vlijmen ◽  
Adrian Mulholland

<p>Ibrutinib is the first covalent inhibitor of Bruton’s tyrosine kinase (BTK) to be used in the treatment of B-cell cancers. Understanding the mechanism of covalent inhibition is crucial for the design of safer and more selective covalent inhibitors that target BTK. There are questions surrounding the precise mechanism of covalent bond formation in BTK as there is no appropriate active site residue that can act as a base to deprotonate the cysteine thiol prior to covalent bond formation. To address this, we have investigated several mechanistic pathways of covalent modification of C481 in BTK by ibrutinib using QM/MM reaction simulations. The lowest energy pathway we identified involves a direct proton transfer from C481 to the acrylamide warhead in ibrutinib, followed by covalent bond formation to form an enol intermediate. There is a subsequent rate-limiting keto-enol tautomerisation step (DG<sup>‡</sup>=10.5 kcal mol<sup>-1</sup>) to reach the inactivated BTK/ibrutinib complex. Our results represent the first mechanistic study of BTK inactivation by ibrutinib to consider multiple mechanistic pathways. These findings should aid in the design of covalent drugs that target BTK and related proteins. </p>


2021 ◽  
Author(s):  
Sreejith Mangalath ◽  
Suneesh C Karunakaran ◽  
Gary Newnam ◽  
Gary Schuster ◽  
Nicholas Hud

A goal of supramolecular chemistry is to create covalent polymers of precise composition and stereochemistry from complex mixtures by the reversible assembly of specific monomers prior to covalent bond formation....


Author(s):  
Vishal Srivastava ◽  
Pravin Kumar Singh ◽  
Shraddha Tivari ◽  
Praveen Pratap Singh

Visible light and photoredox catalysis have emerged as a powerful and long-lasting tool for organic synthesis, demonstrating the importance of a variety of chemical bond formation methods. Natural products, physiologically...


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