Search results for " bonding"
showing 10 items of 934 documents
Bile acid–cysteamine conjugates: Structural properties, gelation, and toxicity evaluation
2011
Abstract Design, synthesis, and characterization of six novel bile acid–cysteamine conjugates together with investigation of their structural studies, gelation properties, and preliminary toxicity evaluation, are reported. Solid state properties of selected compounds were studied by means of X-ray diffraction and 13C CPMAS NMR spectroscopy. N-(2-thioethyl)-3α,7α,12α-trihydroxy-5β-cholan-24-amide was shown to exhibit (pseudo)polymorphism, and a single crystal structure of its non-stoichiometric hydrate is reported herein. Cholyl and dehydrocholyl derivatives bearing three functionalities in their steroidal backbone were shown to undergo self-assembly leading to gelation in certain organic so…
Emocionālā statusa un saiknes ar jaundzimušo salīdzinājums sievietēm pēc dzemdībām pa dabiskiem ceļiem un pēc ķeizargrieziena operācijas
2017
Pētījuma mērķis bija izpētīt, vai dzemdību veids – ķeizargrieziens vai dzemdības pa dabīgiem ceļiem, ietekmē mātes pēcdzemdību psiho-emocionālo status un mātes-bērna saiknes izveidošanos. Mātes emocionālais stāvoklis tika novērtēts ar tā saucamo Edinburgas Pēcdzemdību Depresijas Skalu (EPDS). Skala tika iekļauta pētījumā izmantotā anketā, kuru aizpildīja pētījuma dalībnieces. Ar EPDS nosaka mātes risku uz pēcdzemdību depresijas attīstību, kur iegūto punktu skaitu interpretē sekojoši: 0-9 punkti nozīmē zemu, 9-13 vidējo un >13 punktiem augstu risku uz pēcdzemdību depresijas attīstību. Pēcdzemdību perioda pirmās nedēļas laikā siviete stresa rezultātā var piedzīvot tā saucamo “Baby Blues”, jeb…
Comparative analysis of the electronic structures of mono- and bi-atomic chains of IV, III–V and II–VI group elements calculated using the DFT LCAO a…
2015
Using the first principle non-relativistic linear combination of atomic orbitals (LCAO) and relativistic linearized augmented cylindrical wave (LACW) methods, the band structure of the covalent and partially ionic ANB8−N single atom width chain is calculated. Both the LCAO and LACW methods show that the chains of C, Si, Ge, Sn, and Pb are metallic. However, there is a great difference between the relativistic and non-relativistic band structures. The π bands crossing the Fermi level are orbitally doubly degenerate in the non-relativistic model. The relativistic LACW calculations demonstrate that the spin and orbital motion of electrons are coupled, thereby splitting the π bands. The spin–or…
<title>Functional models of electrochromic devices: cycling capacity and degradation</title>
1997
Electrical transfer and diffusion of ions and the irreversibility of ion and electron processes in heterojunctions are responsible for degradation of ionic devices. These processes for electrochromic devices (ECD) determine the cycling capacity and lifetime. The basic problem here is how to match the electrochemical parameters (including chemical potential) of heterojunction. The experiments had been carried out on ECD based on system: (phi) - -(phi) , where AAH is solid electrolyte based on antimony acid hydrates. The cycling capacity and degradation processes of ECD are investigated by electro-optical and electro-chemical spectroscopy. The analysis of experimental data are based on assump…
Synthesis and characterisation of N-glycosyl amines from the reaction between 4,6-O-benzylidene-D-glucopyranose and substituted aromatic amines and a…
2001
Twelve N-glycosyl amines were synthesised using 4,6-O–benzylidene-D-glucopyranose and different substituted aromatic amines, including some diamines that resulted in bis-glycosyl amines. Another set of six N–glycosyl amines was synthesised using different hexoses and pentoses and 2–(o–aminophenyl)benzimidazole. All compounds were isolated as solid products and purified, their elemental compositions were established, and these were characterised by NMR (1H and 13C), UV–Vis, and FTIR spectroscopy, by FAB mass spectrometry (molecular-ion peaks gave molecular weights), and by their optical rotations. While the protected saccharide, 4,6-O-benzylidene-D-glucopyranose, exists as a mixture of β and…
Discovery of benzimidazole-based Leishmania mexicana cysteine protease CPB2.8ΔCTE inhibitors as potential therapeutics for leishmaniasis
2018
Abstract: Chemotherapy is currently the only effective approach to treat all forms of leishmaniasis. However, its effectiveness is severely limited due to high toxicity, long treatment length, drug resistance, or inadequate mode of administration. As a consequence, there is a need to identify new molecular scaffolds and targets as potential therapeutics for the treatment of this disease. We report a small series of 1,2‐substituted‐1H‐benzo[d]imidazole derivatives (9ad) showing affinity in the submicromolar range (Ki = 0.150.69 μM) toward Leishmania mexicanaCPB2.8ΔCTE, one of the more promising targets for antileishmanial drug design. The compounds confirmed activity in vitro against intrace…
Full and Partial Agonism of Ionotropic Glutamate Receptors Indicated by Molecular Dynamics Simulations
2011
Ionotropic glutamate receptors (iGluRs) are synaptic proteins that facilitate signal transmission in the central nervous system. Extracellular iGluR cleft closure is linked to receptor activation; however, the mechanism underlying partial agonism is not entirely understood. Full agonists close the bilobed ligand-binding domain (LBD), while antagonists prevent closure; the transmembrane ion channel either opens or stays closed, respectively. Although some bulky partial agonists produce intermediate iGluR-LBD closure, the available crystal structures also imply that the cleft can be shut with certain partial agonists. Recently, we have shown that the iGluR-LBD closure stage can be recreated b…
The role of size and protein shells in the toxicity to algal photosynthesis induced by ionic silver delivered from silver nanoparticles
2019
Abstract Because of their biocide properties, silver nanoparticles (AgNPs) are present in numerous consumer products. The biocidal properties of AgNPs are due to both the interactions between AgNP and cell membranes and the release of dissolved silver (Ag+). Recent studies emphasized the role of different nanoparticle coatings in complexing and storing Ag+. In this study, the availability of dissolved silver in the presence of algae was assessed for three AgNPs with different silver contents (59%, 34% and 7% of total Ag), silver core sizes and casein shell thicknesses. The impact of ionic silver on the photosynthetic yield of Chlamydomonas reinhardtii was used as a proxy to estimate the amo…
Influence of chitin nanocrystals on the dielectric behaviour and conductivity of chitosan-based bionanocomposites
2018
[EN] A series of bionanocomposite films based on chitosan, reinforced with chitin nanocrystals, were developed, and assessed in terms of dielectric behaviour and conductivity by using an experimental methodology that allows avoiding the conductivity contribution and the exclusion of contact and interfacial polarization effects. The dielectric relaxations at low and high frequency and temperatures were modeled by Havriliak-Negami functions. Below the glass transition temperature (Tg), the gamma and beta relaxations were observed, which were related to intramolecular and non-cooperative segmental movements. At higher temperatures, an intermolecular and cooperative macromolecular movement, rel…
Colloidal stability of halloysite clay nanotubes
2019
Abstract The colloidal stability of halloysite clay nanotubes dispersion is reviewed showing the strategy and the mechanism to obtain stable systems in water and apolar solvents. The selective modification of halloysite inner/outer surfaces can be achieved by exploiting electrostatic interactions. The adsorption of anionic surfactants onto the halloysite cavity allows generating inorganic cylindrical micelles that can be separated from the solvent. On the other hand, the functionalization of halloysite shell by positively charged surfactants drives to obtain stable water-in-oil emulsions. The interactions with ionic and nonionic polymers alters the dispersability of halloysite due to electr…