Search results for "D2"
showing 10 items of 2418 documents
Identifiability problem for recovering the mortality rate in an age-structured population dynamics model
2014
In this article is studied the identifiability of the age-dependent mortality rate of the Von Foerster–Mc Kendrick model, from the observation of a given age group of the population. In the case where there is no renewal for the population, translated by an additional homogeneous boundary condition to the Von Foerster equation, we give a necessary and sufficient condition on the initial density that ensures the mortality rate identifiability. In the inhomogeneous case, modelled by a non-local boundary condition, we make explicit a sufficient condition for the identifiability property, and give a condition for which the identifiability problem is ill-posed. We illustrate this latter case wit…
Synthesis of highly functionalized β-aminocyclopentanecarboxylate stereoisomers by reductive ring opening reaction of isoxazolines
2012
A rapid and simple procedure was devised for the synthesis of multifunctionalized cyclic β-amino esters and γ-amino alcohols via the 1,3-dipolar cycloaddition of nitrile oxides to β-aminocyclopentenecarboxylates. The opening of the isoxazoline reductive ring to the corresponding highly functionalized 2-aminocyclopentanecarboxylates occurred stereoselectively with good yields.
Photodegradation of Brilliant Green Dye by a Zinc bioMOF and Crystallographic Visualization of Resulting CO2
2021
We present a novel bio-friendly water-stable Zn-based MOF (1), derived from the natural amino acid L-serine, which was able to efficiently photodegrade water solutions of brilliant green dye in only 120 min. The total degradation was followed by UV-Vis spectroscopy and further confirmed by single-crystal X-ray crystallography, revealing the presence of CO2 within its channels. Reusability studies further demonstrate the structural and performance robustness of 1.
Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates
2014
The synthesis of a library of structurally variable aromatic esters of (benzyloxycarbonylamino)(aryl)methylphosphonic acids is described by means of the Oleksyszyn reaction. The library was enlarged by the application of a Suzuki–Miayra approach and by preparation of mixed esters.
Ankk1 Loss of Function Disrupts Dopaminergic Pathways in Zebrafish
2022
Ankyrin repeat and kinase domain containing 1 (ANKK1) is a member of the receptor-interacting protein serine/threonine kinase family, known to be involved in cell proliferation, differentiation and activation of transcription factors. Genetic variation within the ANKK1 locus is suggested to play a role in vulnerability to addictions. However, ANKK1 mechanism of action is still poorly understood. It has been suggested that ANKK1 may affect the development and/or functioning of dopaminergic pathways. To test this hypothesis, we generated a CRISPR-Cas9 loss of function ankk1 zebrafish line causing a 27 bp insertion that disrupts the ankk1 sequence introducing an early stop codon. We found that…
Unveiling the Different Reactivity of Bent and Linear Three-Atom-Components Participating in [3 + 2] Cycloaddition Reactions
2021
The reactivity of a series of pairs of bent and linear three-atom-component (B-TACs and L-TACs) participating in [3 + 2] cycloaddition (32CA) reactions towards ethylene and electrophilic dicyanoethylene (DCE) have been studied within the Molecular Electron Density Theory. While the pseudodiradical structure of B-TACs changes to that of pseudoradical or carbenoid L-TACs upon dehydrogenation, zwitterionic B-TACs remain unchanged. Conceptual Density Functional Theory (CDFT) indices characterize five of the nine TACs as strong nucleophiles participating in polar reactions towards electrophilic ethylenes. The activation energies of the 32CA reactions with electrophilic DCE range from 0.5 to 22.0…
Coordination Chemistry of a Bis(Tetrazine) Tweezer: A Case of Host-Guest Behavior with Silver Salts
2021
The carbon-carbon cross-coupling of phenyl s-tetrazine (Tz) units at their ortho-phenyl positions allows the formation of constrained bis(tetrazines) with original tweezer structures. In these compounds, the face-to-face positioning of the central tetrazine cores is reinforced by π-stacking of the electron-poor nitrogen-containing heteroaromatic moieties. The resulting tetra-aromatic structure can be used as a weak coordinating ligand with cationic silver. This coordination generates a set of bis(tetrazine)-silver(I) coordination complexes tolerating a large variety of counter anions of various geometries, namely, PF6−, BF4−, SbF6−, ClO4−, NTf2−, and OTf−. These compounds were characterized…
Chemometric Tools to Point Out Benchmarks and Chromophores in Pigments through Spectroscopic Data Analyses
2021
Spectral preprocessing data and chemometric tools are analytical methods widely applied in several scientific contexts i.e., in archaeometric applications. A systematic classification of natural powdered pigments of organic and inorganic nature through Principal Component Analysis with a multi-instruments spectroscopic study is presented here. The methodology allows the access to elementary and molecular unique benchmarks to guide and speed up the identification of an unknown pigment and its recipe. This study is conducted on a set of 48 powdered pigments and tested on a real-case sample from the wall painting in S. Maria Delle Palate di Tusa (Messina, Italy). Four spectroscopic techniques …
HPTLC fingerprinting—rapid method for the differentiation of honeys of different botanical origin based on the composition of the lipophilic fractions
2018
Bee honey possess various nutritional and medicinal functions, which are the result of its diverse chemical composition. The numerous bioactive compounds in honey come from flower nectar
Luun morfogeneettisen proteiini 4:n kohdegeenien SKIL ja ID2 vaikutukset rintasyöpäsoluihin
2017
Rintasyöpä on johtava naisten syöpäkuolemien aiheuttaja maailmanlaajuisesti. Luun morfogeneettiset proteiinit (BMP) ovat tranformoiva kasvutekijä beta- superperheeseen kuuluvia proteiineja. BMP:den tiedetään olevan osallisina monissa syöpätyypeissä. Rintasyövässä BMP4:llä on merkittäviä vaikutuksia solukasvuun, liikkuvuuteen ja levinnäisyyteen. Aiempien tutkimusten mukaan BMP4:n on havaittu laskevan solukasvua merkittävästi rintasyöpäsoluilla. Tämän tutkimuksen kohteena oli kaksi BMP4:n kohdegeeniä, ID2 (Inhibitor of DNA binding 2) ja SKIL eli SKI-like proto-onkogeeni. Hypoteesina oli selvittää johtuuko BMP4:n vaikutukset solukasvuun ID2- tai SKIL-geenistä. BT-474 ja T-47D rintasyöpäsoluja …