The degradation kinetics of a new cephalosporin derivative (1) in aqueous solution were investigated at 60 degrees, mu = 0.05, at pH 2.0-10.0. The observed degradation rates followed pseudo-first-order kinetics and were influenced significantly by H2O and OH- catalysis. No primary salt effect was observed in the acid region, but a positive salt effect was observed at pH 9.4. A general base catalytic effect by a phosphate buffer species was observed at pH 7-8. The pH-rate profile for I exhibited a degradation minimum at pH 6.05. The Arrhenius activation energies determined at pH 4.0 and 9.4 were 27.2 and 24.5 kcal/mole, respectively. Excellent agreement between the theoretical pH-rate profile and the experimental data supported the hypothesized degradation process. A comparison of I and cefazolin revealed close structural and stability analogies.
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http://dx.doi.org/10.1002/jps.2600681108 | DOI Listing |
Curr Microbiol
January 2025
Unit of Microbiology and Immunology, ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, 605006, India.
In recent years, there has been a global threat from emerging vector-borne diseases (VBD), despite the implementation of several vector control programs. Considering the benefits of bacterial pesticides, the present study aimed to isolate potential mosquitocidal bacteria from the various soil types collected from the Kasaragod (12.5°N, 75.
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January 2025
Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
The rate at which transcription factors (TFs) bind their cognate sites has long been assumed to be limited by diffusion, and thus independent of binding site sequence. Here, we systematically test this assumption using cell-to-cell variability in gene expression as a window into the in vivo association and dissociation kinetics of the model transcription factor LacI. Using a stochastic model of the relationship between gene expression variability and binding kinetics, we performed single-cell gene expression measurements to infer association and dissociation rates for a set of 35 different LacI binding sites.
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January 2025
State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, P.R. China.
In this study, we introduce a highly effective non-metallic iodine single-atom catalyst (SAC), referred to as I-NC, which is strategically confined within a nitrogen-doped carbon (NC) scaffold. This configuration features a distinctive C-I coordination that optimizes the electronic structure of the nitrogen-adjacent carbon sites. As a result, this arrangement enhances electron transfer from peroxymonosulfate (PMS) to the active sites, particularly the electron-deficient carbon.
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January 2025
Laboratory of Genome Diversification & Integrity, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125, Berlin, Germany.
The establishment of protective immune responses relies on the ability of terminally differentiated B cells to secrete a broad variety of antigen-specific antibodies with different effector functions. RIF1 is a multifunctional protein that promotes antibody isotype diversification via its DNA end protection activity during class switch recombination. In this study, we showed that RIF1 ablation resulted in increased plasmablast formation ex vivo and enhanced terminal differentiation into plasma cells upon immunization.
View Article and Find Full Text PDFToxicon
January 2025
College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China. Electronic address:
Aflatoxin B (AFB) is a highly toxic, carcinogenic, teratogenic, and mutagenic mycotoxin commonly found in corn. In this work, water-assisted microwave irradiation (WMI) was used to degrade AFB in corn, during which the influencing factors and kinetics of AFB degradation were also studied. The results showed that the degree of corn crushing, the heating rate of WMI, the temperature of WMI, the solid-liquid ratio, the initial content of AFB and the microwave power were all important factors affecting the degradation of AFB.
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