Results 51 to 60 of about 261 (135)

Unravelling friction anisotropy by atomic force microscopy

Journal of Microscopy, Volume 302, Issue 1, Page 111-144, April 2026.
Abstract Friction plays a crucial role in both natural phenomena, from the flow of blood cells to earthquakes, and technological applications, from car engines to wind turbines. One of the most fundamental aspects of tribology is friction anisotropy, that is, the dependence of the friction force vector on the direction of sliding.
Clodomiro Cafolla, Marcello Campione
wiley   +1 more source

Synthesis of Peptides, Peptide Nucleic Acid Components, and Other Biogenic Compounds From a Three‐Component Prebiotic Mixture

Chemistry – A European Journal, Volume 32, Issue 9, 2 March 2026.
High‐energy proton irradiation of a formamide–diaminomaleonitrile–glycine system in the presence of meteorites produces a broad spectrum of biogenic compounds, including nucleobases, nucleosides, peptides, and nucleobase–peptide conjugates, highlighting a chemically plausible prebiotic network.
Bruno Mattia Bizzarri, Rosangela Santalucia, Eleonora Mancin, Mikhail Kapralov, Eugene Krasavin, Raffaele Saladino, Ernesto Di Mauro   +6 more
wiley   +1 more source

Radical Retrosynthesis of Natural Products Enabled by Iron‐Based Reductive Olefin Coupling

Angewandte Chemie Novit, Volume 2, Issue 1, March 2026.
This review highlights iron‐catalyzed reductive olefin coupling (ROC)—a strategy for C─C bond formation driven by metal‐hydride hydrogen atom transfer (MHAT)—as a key tool in natural products synthesis. This review surveys dozens of total syntheses employing ROC‐based strategies, highlighting its power to forge strained rings, quaternary centers, and ...
Griffin L. Barnes, Alex L. Rerick, Phil S. Baran   +2 more
wiley   +1 more source

Escherichia coli GutM4 produces 2,5-diketopiperazines and inhibits human pathogens in vitro

Electronic Journal of Biotechnology, 2017
Background: It has been a very common practice to use probiotics or their metabolites as alternative antimicrobial strategies for the treatment and prevention of infections as rampant and indiscriminate use of antibiotics causes the development of ...
Xichun Zhang, Junmin Du, Yu Wang, Shuming Chen, Yingli Wang   +4 more
doaj   +1 more source

Photoisomerization in Cyclic Dipeptide Derivatives: Photoswitchable Supramolecular Hydrogels and the Discovery of Hemipiperazine Photoswitches

ChemPhotoChem, Volume 10, Issue 3, March 2026.
Photoswitchable cyclic dipeptides (CDPs) can be used to prepare hydrogels that reversibly dissipate upon irradiation, or to photomodulate the development of living organisms. We report here applications and perspectives for CDPs containing azobenzene photoswitches or newly discovered hemipiperazine photoswitches in smart materials and biological ...
Zbigniew L. Pianowski
wiley   +1 more source

Comparative Study of the Synthesis and Structural and Physicochemical Properties of Diketopiperazines vs Aza-diketopiperazines

The Journal of Organic Chemistry, 2017
Aza-diketopiperazines (aza-DKPs) represent an underprivileged motif obtained by scaffold hopping of 2,5-diketopiperazines (2,5-DKPs). Herein, we compare the synthesis and the structural and physicochemical properties of aza-DKP 4 vs 2,5-DKP 7. Thus, X-ray and 1H NMR studies show that aza-DKP 4 is a rigid and nonflat scaffold like the 2,5-DKP 7 ...
Regenass, Pierre, Bosc, Damien, Riché, Stéphanie, Gizzi, Patrick, Hibert, Marcel, Karmazin, Lydia, Ganesan, A., Bonnet, Dominique   +7 more
openaire   +5 more sources

Effect of α‐Hydrazino Acids on the Performance of H‐Pro–Pro‐Xaa Catalysts in the Conjugate Addition of Aldehydes to Nitroolefins

ChemistrySelect, Volume 11, Issue 11, 18 March 2026.
The tripeptide Pro‐Pro‐D‐hVal‐OMe, which lacks an acidic group, catalysed the conjugate addition of aldehydes to nitroolefins and afforded γ‐nitroaldehydes in 79–97% yield and 88:14–93:7 e.r. The proposed reaction mechanism relies on the active role of hydrazide NHβ or NHα protons in hydrogen bonding with the reacting species.
Ivona Banović, Ivana Nikšić‐Franjić, Ivanka Jerić   +2 more
wiley   +1 more source

A Bifunctional Cytochrome P450 Enzyme Catalyzes Hydroxylation and Aryl‐Aryl Ether Formation in the Biosynthesis of Emestrin

Chemistry – A European Journal, Volume 32, Issue 7, 16 February 2026.
Conversion of emestrin J (5) to emestrin (1) by three P450 enzymes from the cluster (eme) in Emericella quadrilineata. EmeO acts as a bifunctional enzyme for the construction of the 15‐membered lactone ring via an aryl‐aryl ether bond formation and simultaneous hydroxylation between phenolic and nonphenolic aromatic rings, while EmeE and EmeR install ...
Yu‐Chuan Chen, Jing‐Jing Wu, Ming‐Hua Chen, Shu‐Ming Li   +3 more
wiley   +1 more source

Diverse Secondary Metabolites from the Marine-Derived Fungus Dichotomomyces cejpii F31-1

Marine Drugs, 2017
By adding l-tryptophan and l-phenylalanine to GPY medium, twenty-eight compounds, including amides, polyketides, a sesquiterpenoid, a diterpenoid, a meroterpenoid, diketopiperazines, β-carbolines, fumiquinazolines, and indole alkaloids, were discovered ...
Yan-Xiu Chen, Meng-Yang Xu, Hou-Jin Li, Kun-Jiao Zeng, Wen-Zhe Ma, Guo-Bao Tian, Jun Xu, De-Po Yang, Wen-Jian Lan   +8 more
doaj   +1 more source

Microbial diversity of saline environments: searching for cytotoxic activities

AMB Express, 2017
In order to select halophilic microorganisms as a source of compounds with cytotoxic activities, a total of 135 bacterial strains were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes.
Carolina Díaz-Cárdenas, Angela Cantillo, Laura Yinneth Rojas, Tito Sandoval, Susana Fiorentino, Jorge Robles, Freddy A. Ramos, María Mercedes Zambrano, Sandra Baena   +8 more
doaj   +1 more source