Search results for "Irad"
showing 10 items of 98 documents
Dažādu antibakteriālo augu ekstraktu antiradikālās aktivitātes kinētiskā izpēte
2017
Dažādu antibakteriālo augu ekstraktu antiradikālās aktivitātes kinētiskā izpēte. Džabijeva D., zinātniskās vadītājas Dr. ķīm Ilva Nakurte, Dr. biol. Anete Borodušķe, Maģistra darbs, 101 lappuse, 33 attēli, 11 tabulas, 74 literatūras avoti, 3 pielikumi. Latviešu valodā. Literatūras apskatā apkopota informācija par lielo struteni, parasto mirti, burvju lazdu, parasto kadiķi, parasto rasaskrēsliņu un paragvajas ileksu (Yerba mate) augu antibakteriālo un antiradikālo aktivitāti un tās kinētiku, kā arī par aktīvu antioksidantu – hlorogēnskābi. Izmantojot UV/VIS spektroskopiju, veikti lielās strutenes, mirtes, burvju lazdas, kadiķu, rasaskrēsliņa, matē etanola un glicerīna/ūdens ekstraktu un hlor…
Contraddizioni urbanistiche della Zona Espansione Nord 2 a Palermo
2008
Viene sviluppata una lettura del quartiere ZEN di Palermo sulla base di conoscenze dirette vissute nel periodo di formazione del progetto. Dal testo si evince come il progetto voleva riproporre le dimensioni dell’insula del centro storico di Napoli. Gli errori principali appaiono essere l’accentuato isolamento che il quartiere ha subito nel tempo, il rapporto che le costruzioni hanno con l’impianto viario, l’assenza di servizi della vita collettiva. I rimedi adottati dal Prg di Palermo accentuano l’isolamento affidando al diradamento la possibilità dell’integrazione, mentre sarebbe più opportuno produrre un contesto di maggiore densità capace di assorbire lo ZEN nella città esistente anche …
Torsional Bias as a Strategy To Tune Singlet–Triplet Gaps in Organic Diradicals
2018
Quinoidal compounds with proaromatic structures possess differing degrees of diradical character, where the open-shell diradical resonance form has restored aromaticity throughout the compound. Methods to tune the diradical character of these compounds have traditionally focused on altering the length and the molecular composition of the π-conjugated backbones. However, other molecular design strategies to tune the singlet–triplet gap of π-conjugated quinoidal molecules have not been extensively explored. We previously reported a strikingly small energy gap between the quinoidal and diradical states of a quinoidal small molecule containing methano[10]annulene (TMTQ) that was dictated in lar…
Fluoreno[2,1-a]fluorene: an ortho-naphthoquinodimethane-based system with partial diradical character.
2019
Fluoreno[2,1-a]fluorene, a molecule comprising fused ortho-quinodimethane units in a 1,5-napthoquinodimethane core, has been prepared and investigated with spectroscopy (UV-Vis-NIR, 1H-NMR and Raman), SQUID magnetometry, spectroelectrochemistry and quantum chemistry. While para-quinodimethanes with a 2,6-substitution pattern exist as closed-shell species and meta-quinodimethanes with 2,7-substitution favour a ground electronic state with very large diradical character, our 1,5-substituted ortho-naphthoquinodimethane-based system exhibits an intermediate degree of diradical character.
Experimental and Theoretical Studies on Magnetic Exchange in Silole-Bridged Diradicals.
2006
International audience; Five bis(tert-butylnitroxide) diradicals connected by a silole [2,5-R2-3,4-diphenylsilole; R = Me3CN(®O.bul.)Z; Z = p-C6H4 (7a), p-C6H4C6H4-p (7b), 1,4-naphthalenediyl (7c), m-C6H4 (7d)] or a thiophene [2,5-R2-thiophene; R = p-Me3CN(®O.bul.)C6H4 (12)] ring as a coupler were studied. Compd. 12 crystallizes in the orthorhombic space group Pna21 with a 20.752(5), b 5.826(5), and c 34.309(5) .ANG.. X-ray crystal structure detn., electronic spectroscopy, variable-temp. EPR spectroscopy, SQUID measurements and DFT computations (UB3LYP/6-31+G*) were used to study the mol. conformations and electronic spin coupling in this series of mols. Whereas compds. 7b, 7c, and 7d are q…
Los infractores de tráfico persistentes: el consumo de alcohol y la personalidad como predictores de la retirada del permiso de conducir
2020
ABSTRACT Traffic safety is an important social problem. Many accidents are due to non-compliance with traffic regulations. Serious or repeated offenses are sanctioned with penalty points or court conviction, and sanctions can lead to disqualification from driving. This paper explores the relevance of alcohol consumption and personality factors as predictors of driving disqualification. The aim of the study is to determine whether the behaviors of persistent offenders and their propensity for law-breaking are related to their characteristics and patterns of drinking. A sample of 358 drivers participated in the study: 126 non-offender habitual drivers and 232 persistent traffic offenders disq…
Understanding the mechanism of non-polar diels-alder reactions. A comparative elf analysis of concerted and stepwise diradical mechanisms
2010
The electron-reorganization along the concerted and stepwise pathways associated with the non-polar Diels-Alder reaction between cyclopentadiene (Cp, 1) and ethylene (2) has been studied using the topological analysis of the electron localization function (ELF) at the B3LYP/6-31G(d) level of theory. ELF results for the concerted mechanism stresses that the electron-reorganization demanded on the diene and ethylene reagents to reach two pseudo-diradical structures is responsible for the high activation energy. A comparative ELF analysis of some relevant points of the non-polar Diels-Alder reaction between Cp and styrene (10) suggests that these concerted mechanisms do not have a pericyclic e…
Innovations in endodontic filling materials
2012
One of the goals of endodontic treatment is to achieve a complete, tridimensional, hermetic sealing of the root canal system to prevent the entry of microorganisms or their products through both the coronal and apical pathways. Gutta-percha is the most widely used material for root canal filling and despite its numerous properties, such as biocompatibility and thermoplasticity, it has however an important limit: the lack of adhesion to the canal walls. Attempts to address this problem have been made over the years by using endodontic cements capable of bonding to canal dentine but their tendency to resorption in time can compromise the quality of treatment. The first step towards a real adh…
Diindenoanthracene Diradicaloids Enable Rational, Incremental Tuning of Their Singlet-Triplet Energy Gaps
2020
Summary A fundamental understanding of the inherent electronic and magnetic properties of open-shell diradicaloids is essential so that these properties can be modified to create molecules that meet the potential needs of industry. However, there have been very few attempts to date to systematically accomplish this in diradicaloid compounds. Here, we present the synthetic, spectroscopic, and computational investigation of a series of molecules based on the diindeno[1,2-b:1′,2′-g]anthracene framework. Calculations suggest that by altering the transfer integral term, tab, we are able to manipulate the diradical character and, thus, ΔEST within this series of molecules. Experimentally determin…
Chemical Composition Analysis, Antimicrobial Activity and Cytotoxicity Screening of Moss Extracts (Moss Phytochemistry)
2015
Mosses have been neglected as a study subject for a long time. Recent research shows that mosses contain remarkable and unique substances with high biological activity. The aim of this study, accordingly, was to analyze the composition of mosses and to screen their antimicrobial and anticancer activity. The total concentration of polyphenols and carbohydrates, the amount of dry residue and the radical scavenging activity were determined for a preliminary evaluation of the chemical composition of moss extracts. In order to analyze and identify the substances present in mosses, two types of extrahents (chloroform, ethanol) and the GC/MS and LC-TOF-MS methods were used. The antimicrobial activ…