The interpeptidic Cu exchange rate constants were measured for two Cu amyloid-β complexes, Cu(Aβ) and Cu(Aβ), to fluorescent peptides GHW and DAHW using a quantitative tryptophan fluorescence quenching methodology. The second-order rate constants were determined at three pH values (6.8, 7.4, and 8.7) important to the two Cu(Aβ) coordination complexes, components Cu(Aβ) and Cu(Aβ). The interpeptidic Cu exchange rate constant is approximately 10 M s but varies in magnitude depending on many variables. These include pH, length of the Aβ peptide, location of the anchoring histidine ligand in the fluorescent peptide, number of amide deprotonations required in the tryptophan peptide to coordinate Cu, and interconversion between Cu(Aβ) and Cu(Aβ). We also present EPR data probing the Cu exchange between peptides and the formation of ternary species between Cu(Aβ) and GHW. As the nonfluorescent GHK and DAHK peptides are important motifs found in the blood and serum, their ability to sequester Cu ions from Cu(Aβ) complexes may be relevant for the metal homeostasis and its implication in Alzheimer's disease. Thus, their kinetic Cu interpeptidic exchange rate constants are important chemical rate constants that can help elucidate the complex Cu trafficking puzzle in the synaptic cleft.
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http://dx.doi.org/10.1021/acs.inorgchem.0c03555 | DOI Listing |
Front Public Health
December 2024
Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA, United States.
Background: Mass vaccination is a cornerstone of public health emergency preparedness and response. However, injudicious placement of vaccination sites can lead to the formation of long waiting lines or , which discourages individuals from waiting to be vaccinated and may thus jeopardize the achievement of public health targets. Queueing theory offers a framework for modeling queue formation at vaccination sites and its effect on vaccine uptake.
View Article and Find Full Text PDFArch Orthop Trauma Surg
January 2025
The Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta Pei Road, Niao Sung Dist, Kaohsiung, Taiwan.
Introduction: The optimal management strategy for unstable distal clavicular fractures remains controversial. Recent studies on plate techniques have reported good-to-excellent outcomes with no serious complications. The questions are that: (1) Does the use of wire augmentation with locking plate in distal part (distal wire augmentation) reduce radiographic loss of reduction (RLOR) and get earlier bony union in distal clavicular fractures? (2) Which fixation methods are associated with a higher incidence of acromioclavicular (AC) joints arthritis or subluxation? We collected and analyzed clinical studies on different plate fixation methods for unstable fractures to identify the best surgical modality.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Chemistry, Faculty of Science, Umm Al-Qura University, 21955 Makkah, Saudi Arabia.
With the growing threat of organic pollutants in water bodies, there is an urgent need for sustainable and efficient water decontamination methods. This research focused on synthesizing a novel Z-scheme ternary heterostructure composed of graphene oxide (GO)-mediated polyaniline (PANI) with α-FeO and investigated its potential in brilliant green (BrG) and ciprofloxacin (CIP) degradation tests under visible light. The ternary composite demonstrated exceptional photocatalytic activity, with the optimized 10%PANI/GO/α-FeO (10PGF) photocatalyst achieving 99.
View Article and Find Full Text PDFNeotrop Entomol
January 2025
Programa de Pós-Graduação Em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Lab de Limnologia, Univ Federal Do Rio Grande, Rio Grande, RS, Brazil.
Chironomidae have a wide distribution in Neotropical aquatic ecosystems and are predominant in the macroinvertebrate biota of these ecosystems, such as shallow lakes and swamps. In recent years, there has been a notable increase in research efforts aimed at understanding the biology of chironomid, and research on the bionomy of this group is still limited. Therefore, the objective of this study was to describe the growth and development of Chironomus calligraphus and Goeldichironomus holoprasinus, maintained under controlled laboratory conditions.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry, Building 207, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
The rate of reaction between ions in solution depends on solvent properties like permittivity and ionic strength. The influence of a solution's ionic strength is described by the Brønsted-Bjerrum equation. We show how this equation can be derived directly from transition-state theory without introducing the concept of activity coefficients.
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