The nature of hydrogen bonding in condensed ammonia phases, liquid and crystalline ammonia has been a topic of much investigation. Here, we use quantum molecular dynamics simulations to investigate hydrogen bond structure and lifetimes in two ammonia phases: liquid ammonia and crystalline ammonia-I. Unlike liquid water, which has two covalently bonded hydrogen and two hydrogen bonds per oxygen atom, each nitrogen atom in liquid ammonia is found to have only one hydrogen bond at 2.24 Å. The computed lifetime of the hydrogen bond is ≅ 0.1 ps. In contrast to crystalline water-ice, we find that hydrogen bonding is practically nonexistent in crystalline ammonia-I.
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http://dx.doi.org/10.1021/acs.jpclett.2c01608 | DOI Listing |
Chembiochem
December 2024
University of Minnesota, Department of Genetics, Cell Biology, and Development, MCB 5-130, 420 Washington Avenue SE, 55455, Minneapolis, UNITED STATES OF AMERICA.
RNA exhibits remarkable capacity as a functional polymer, with broader catalytic and ligand-binding capability than previously thought. Despite this, the low side chain diversity present in nucleic acids (two purines and two pyrimidines) relative to proteins (20+ side chains of varied charge, polarity, and chemical functionality) limits the capacity of functional RNAs to act as environmentally responsive polymers, as is possible for peptide-based receptors and catalysts. Here we show that incorporation of the modified nucleobase 2-thiouridine (2sU) into functional (aptamer and ribozyme) RNAs produces functionally inactivated polymers that can be activated by oxidative treatment.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
December 2024
National Engineering Research Center for Marine Aquaculture, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, China.
In the study, Sargassum horneri (S. horneri) was used to create a novel zeolite-like algal biochar (KSBC). KSBC with doping of N, O, S, Al, and Si, displayed zeolite-like properties, including well-developed porosity, a high specific surface area (1137.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry, Duke University, Durham, NC 27708.
Invasive fungal infections are a leading cause of death worldwide. Translating molecular insights into clinical benefits is challenging because fungal pathogens and their hosts share similar eukaryotic physiology. Consequently, current antifungal treatments have limited efficacy, may be poorly fungicidal in the host, can exhibit toxicity, and are increasingly compromised by emerging resistance.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Department of Chemistry, University of Delhi-110007, New Delhi, India.
Wastewater contamination by organic dyes, especially Rhodamine B (RhB), possess a significant environmental challenge. This study explores a novel bio sorbent for the removal of RhB dye from contaminated water, using chitosan trisodium citrate-modified magnetic nanoparticles (Fe₃O₄@CSTSC@PANI) coated with polyaniline. The nanocomposite was characterized by FT-IR, XRD, HRTEM, SEM, BET surface analysis.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
December 2024
Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
Significant progress has been achieved with diversity of short peptide supramolecular assemblies. However, their programmable phase modulation by single stimulus remains a great challenge. Herein, we demonstrate a dipeptide supramolecular system undergoes sequentially coupled phase transitions upon hydrogen bonding association and dissociation triggered by a single fatty acid.
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