Search results for "chemistry [Oligopeptides]"
showing 10 items of 211 documents
Salt release monitoring with specific sensors in "in vitro" oral and digestive environments from soft cheeses
2012
International audience; The objective of the present work is to demonstrate the interest and the feasibility of the measurement of NaCl concentrations in soft cheeses and in particular an in vitro digestion process by the use of chemical sensors. The analyzed matrices were the commercial Italian mozzarella cheeses and domestic cheese base models. The classification of mozzarellas was performed according to their salinity, while the breakdown of cheese base models has been followed both at initial steps of digestion in artificial mouth dispositive mimicking the oral sphere and in a gut-imitating digester (TIM-1). During the breakdown of soft cheese in the digester, the estimated values for N…
Synthesis, Characterization, and Cu(2+) Coordination Studies of a 3-Hydroxy-4-pyridinone Aza Scorpiand Derivative.
2016
The synthesis, acid-base behavior, and Cu(2+) coordination chemistry of a new ligand (L1) consisting of an azamacrocyclic core appended with a lateral chain containing a 3-hydroxy-2-methyl-4(1H)-pyridinone group have been studied by potentiometry, cyclic voltammetry, and NMR and UV-vis spectroscopy. UV-vis and NMR studies showed that phenolate group was protonated at the highest pH values [log K = 9.72(1)]. Potentiometric studies point out the formation of Cu(2+) complexes of 1:2, 2:2, 4:3, 1:1, and 2:1 Cu(2+)/L1 stoichiometries. UV-vis analysis and electrochemical studies evidence the implication of the pyridinone moieties in the metal coordination of the 1:2 Cu(2+)/L1 complexes. L1 shows …
One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles.
2014
Background Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. Results UV–vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies showed spherical Ag NPs in the size regime of ~50-70 nm. Face centered cubic lattice of Ag NPs was confirmed by powder X-ray diffraction (PXRD…
Kitchen chemistry course for chemistry education students: influences on chemistry teaching and teacher education – a multiple case study
2019
AbstractThis study introduces the Kitchen Chemistry (KC) course and its influences on chemistry education as a whole. KC is considered to be a life-relevant learning environment that engages learners in science through the pursuit of personally relevant and meaningful goals. KC, as a form of interdisciplinary learning, aims to develop boundary-crossing skills and to support the development of pupils’ scientific thinking. The purpose of this research was to determine how KC as a context-based teaching approach applies to chemistry education and what it offers to chemistry teaching and teacher education. We found that KC gave lower secondary school pupils the opportunity to understand the che…
Modular Solid-Phase Synthesis of Antiprotozoal Barnesin Derivatives
2020
Here, we applied and optimized a solid support (SP)-based Horner-Wadsworth-Emmons reagent to prepare SP-bound vinylogous amino acids. Subsequent SP-based peptide synthesis, global deprotection, and chemical modifications yielded 14 lipodipeptides carrying vinylogous amino acids, including the natural product barnesin A (1). Biological evaluation revealed that several synthesized derivatives show micromolar to nanomolar inhibitory activity against papain-like cysteine proteases, human cathepsin L, and rhodesain.
“Ultra-sensitive” cardiac troponins: Requirements for effective implementation in clinical practice
2018
The measurement of cardiac troponins, either cardiac troponin I or T, has become the culprit of clinical decision making in patients with suspected acute coronary syndrome (ACS), especially in those with non-ST elevation myocardial infarction (NSTEMI). The leading analytical mainstays of cardiac troponin immunoassays include the limit of blank (LoB), limit of detection (LoD), functional sensitivity, the 99th percentile of a healthy reference population, along with the percentage of “ostensibly healthy” subjects displaying measurable values 50% in the general healthy population. The very recent commercialization of methods with further improved analytical sensitivity (i.e., “ultra-sensitive”…
Applications of Quantum Chemistry in Spectroscopy: Molecules, Complexes of Van der Waals, trapped Molecules
2009
I described in this memory my activities as a researcher at Tomsk well before 2003, in succession to the State University of Tomsk in the Faculty of Physics, Institute of Physics of Siberia, and the Institute of 'Atmospheric Optics, in France since then, mostly at the University of Bourgogne (ICB), but also at the University of Lille I (PhLAM) and the University of Marne-la-Vallée (LCT). Part of my work has been dedicated to the evaluation by calculating ab initio of rovibrational constants for quasi-spherical molecules. The centrifugal distortion constants and the dipole moment of the molecule SO2F2 were calculated to validate the tensor theory and interpreter the spectrum. I twas shown th…
KOSMOS 2017 Peru Side Experiment: nutrients, phytoplankton abundances, enzyme rates, photophysiology
2022
This data was collected during an short-term incubation experiment in March 2017 that investigated the response of a surface plankton community to upwelling. This experiment was carried in the framework of the SFB754-funded KOSMOS mesocosm study that took place in La Punta, Callao, Peru between February-April 2017. A total of six different treatments were used to disentangle chemical and biological characteristics of deep water that influence surface plankton blooms: 2 different deep water sources with different nutrient concentrations; 3 treatments to distinguish the effects of inorganic nutrients, organic nutrients and deep water microbial populations. Measured variables include inorganic…
Student experiences of project-based learning in an analytical chemistry laboratory course in higher education
2020
Abstract This study describes students’ experiences in project-based learning (PjBL) incorporated as part of a revised undergraduate analytical chemistry laboratory course. We examined which phases were the easiest as well as the most challenging and what student skills developed during the research project. The research data were collected between 2016 and 2018 via two questionnaires. They were analyzed both quantitatively and qualitatively. One questionnaire focused on the whole course (in 2016–2018, n = 127) of which only the answers on the research project questions were analyzed. The other questionnaire focused on only the research project (in 2018, n = 42). Based on the results of our…
Dipeptidyl Enoates As Potent Rhodesain Inhibitors That Display a Dual Mode of Action
2015
Dipeptidyl enoates were prepared through a high-yielding two-step synthetic route. They have a dipeptidic structure with a 4-oxoenoate moiety as a warhead with multiple reactive sites. Dipeptidyl enoates were screened against rhodesain and human cathepsins B and L, and were found to be potent and selective inhibitors of rhodesain. Among them (S,E)-ethyl 5-((S)-2-{[(benzyloxy)carbonyl]amino}-3-phenylpropanamido)-7-methyl-4-oxooct-2-enoate (6) was the most potent, with an IC50 value of 16.4 nm and kinact/Ki=1.6×106 m−1 s−1 against rhodesain. These dipeptidyl enoates display a reversible mode of inhibition at very low concentrations and an irreversible mode at higher concentrations. Inhibition…