Molecular cluster ions H(+)(H(2)O)(n), H(+)(pyridine)(H(2)O)(n), H(+)(pyridine)(2)(H(2)O)(n), and H(+)(NH(3))(pyridine)(H(2)O)(n) (n = 16-27) and their reactions with ammonia have been studied experimentally using a quadrupole-time-of-flight mass spectrometer. Abundance spectra, evaporation spectra, and reaction branching ratios display magic numbers for H(+)(NH(3))(pyridine)(H(2)O)(n) and H(+)(NH(3))(pyridine)(2)(H(2)O)(n) at n = 18, 20, and 27. The reactions between H(+)(pyridine)(m)(H(2)O)(n) and ammonia all seem to involve intracluster proton transfer to ammonia, thus giving clusters of high stability as evident from the loss of several water molecules from the reacting cluster. The pattern of the observed magic numbers suggest that H(+)(NH(3))(pyridine)(H(2)O)(n) have structures consisting of a NH(4)(+)(H(2)O)(n) core with the pyridine molecule hydrogen-bonded to the surface of the core. This is consistent with the results of high-level ab initio calculations of small protonated pyridine/ammonia/water clusters.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp3021326 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Involving national stakeholders in a systems approach to map drivers of childhood obesity and actions to prevent childhood obesity in Denmark: the Generation Healthy Kids Study.
Health Res Policy Syst
January 2025
Center for Clinical Research and Prevention, Health Promotion and Prevention, Frederiksberg Hospital, Frederiksberg, Denmark.
Background: Childhood obesity is a preventable global public health challenge, increasingly recognized as a complex problem, stemming from complex drivers. Obesity is characterized by multiple interdependencies and diverse influences at different societal levels. Tackling childhood obesity calls for a holistic approach that engages with complexity and recognizes that there is no single "magic bullet" intervention to prevent obesity.
View Article and Find Full Text PDFRecombinant production platform for Group A Streptococcus glycoconjugate vaccines.
NPJ Vaccines
January 2025
Division of Molecular Microbiology, School of Life Sciences, Dundee, United Kingdom.
Group A Streptococcus (Strep A) is a human-exclusive bacterial pathogen killing annually more than 500,000 patients, and no current licensed vaccine exists. Strep A bacteria are highly diverse, but all produce an essential, abundant, and conserved surface carbohydrate, the Group A Carbohydrate, which contains a rhamnose polysaccharide (RhaPS) backbone. RhaPS is a validated universal vaccine candidate in a glycoconjugate prepared by chemical conjugation of the native carbohydrate to a carrier protein.
View Article and Find Full Text PDFLentivirus-mediated gene therapy for Fabry disease: 5-year End-of-Study results from the Canadian FACTs trial.
Clin Transl Med
January 2025
Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Background: Fabry disease is an X-linked lysosomal storage disorder due to a deficiency of α-galactosidase A (α-gal A) activity. Our goal was to correct the enzyme deficiency in Fabry patients by transferring the cDNA for α-gal A into their CD34+ hematopoietic stem/progenitor cells (HSPCs). Overexpression of α-gal A leads to secretion of the hydrolase; which can be taken up and used by uncorrected bystander cells.
View Article and Find Full Text PDFAnalysis of the MODIST Sequence for Selective Proton-Proton Recoupling.
J Phys Chem A
January 2025
Department of NMR based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, Göttingen 37077, Germany.
Theoretical and simulated analyses of selective homonuclear dipolar recoupling sequences serve as primary tools for understanding and determining the robustness of these sequences under various conditions. In this article, we investigate the recently proposed first-order dipolar recoupling sequence known as MODIST (Modest Offset Difference Internuclear Selective Transfer). We evaluate the MODIST transfer efficiency, assessing its dependence on rf-field strengths and the number of simulated spins, extending up to 10 spins.
View Article and Find Full Text PDFScreening and identification of antimicrobial peptides from the gut microbiome of cockroach Blattella germanica.
Microbiome
December 2024
MOE Key Laboratory of Bio-Intelligent Manufacturing, School of Bioengineering, Dalian University of Technology, Dalian, Liaoning, 116024, China.
Article Synopsis
- * Researchers identified and validated an AMP, named AMP1, which has broad-spectrum antibacterial activity and minimal toxicity to human cells, showing potential as a safer alternative to traditional antibiotics.
- * The study emphasizes the effective screening of natural AMPs and highlights AMP1's ability to affect bacterial cell wall synthesis and promote wound healing, suggesting it could be a viable option for clinical use.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!