Search results for "Esteri"
showing 10 items of 220 documents
Insights into Intrinsic Defects and the Incorporation of Na and K in the Cu2ZnSnSe4 Thin-Film Solar Cell Material from Hybrid-Functional Calculations
2016
We have performed density functional theory calculations using the HSE06 hybrid functional to investigate the energetics, atomic, and electronic structure of intrinsic defects as well as Na and K impurities in the kesterite structure of the Cu2ZnSnSe4 (CZTSe) solar cell material. We found that both Na and K atoms prefer to be incorporated into this material as substitutional defects in the Cu sublattice. At this site highly stable (Na–Na), (K–K), and (Na–K) dumbbells can form. While Na interstitial defects are stable in CZTSe, the formation of K interstitial defects is unlikely. In general, the calculated formation energies for Na-related defects are always lower compared to their K-related…
Extraction of lipids from wet microalga Auxenochlorella protothecoides using pulsed electric field treatment and ethanol-hexane blends
2017
Abstract Pulsed Electric Field (PEF) treatment was used as pre-treatment on the microalgae strain Auxenochlorella protothecoides (A.p.) prior to organic solvent extraction of lipids. Experiments were performed on fresh biomass from mixotrophic or autotrophic culture which both had an evaluated lipid content of 30–35% of cell dry weight. Lipid yield was determined gravimetrically and compared to the reference lipid content assessed by bead-milling and subsequent Soxhlet extraction. The biomass was concentrated at 10% w/w solids prior to PEF-treatment and further dewatered afterwards to approximately 25% w/w before extraction. PEF-treatment with an energy input of 1.5 MJ per kilogram of dry m…
Vegetation structure and greenness in Central Africa from Modis multi-temporal data.
2013
African forests within the Congo Basin are generally mapped at regional scale as broad-leaved evergreen forests, with a main distinction between terra-firme and swamp forests types. At the same time, commercial forest inventories, as well as national maps, have highlighted a strong spatial heterogeneity of forest types. A detailed vegetation map generated using consistent methods is needed to inform decision makers about spatial forest organisation and theirs relationships with environmental drivers in the context of global change. We propose a multi-temporal remotely sensed data approach to characterize vegetation types using vegetation index annual profiles. The classifications identified…
Sterol and ecdysteroids profiles of Serratula tinctoria (L.) : plant and cell cultures producing steroids
1993
Abstract Cell suspension cultures have been obtained from Serratula tinctoria, a plant producing ecdysteroids. Sterol profiles and ecdysteroid contents have been analysed and compared in plants and cell cultures. In particular, the composition of free and esterified sterols was investigated using appropriate analytical techniques. In plants, esterified sterols were more abundant (50–70% of the total sterol) than in cell cultures (13–36%). A selectivity for sterol esterification was noted: in plants, the triterpenes (as amyrins) were esterified, whereas it was the 4-desmethylsterols (sitosterol and cholesterol) in cell cultures. Ecdysteroids were present in higher quantities in plant (0.1–1.…
Circulating exosomes deliver free fatty acids from the bloodstream to cardiac cells: Possible role of CD36
2019
Regulation of circulating free fatty acid (FFA) levels and delivery is crucial to maintain tissue homeostasis. Exosomes are nanomembranous vesicles that are released from diverse cell types and mediate intercellular communication by delivering bioactive molecules. Here, we sought to investigate the uptake of FFAs by circulating exosomes, the delivery of FFA-loaded exosomes to cardiac cells and the possible role of the FFA transporter CD36 in these processes. Circulating exosomes were purified from the serum of healthy donors after an overnight fast (F) or 20 minutes after a high caloric breakfast (postprandial, PP). Western blotting, Immunogold Electron Microscopy and FACS analysis of circu…
Overactivation of the endocannabinoid system alters the antilipolytic action of insulin in mouse adipose tissue.
2017
Evidence has accumulated that obesity-related metabolic dysregulation is associated with overactivation of the endocannabinoid system (ECS), which involves cannabinoid receptor 1 (CB1R), in peripheral tissues, including adipose tissue (AT). The functional consequences of CB1R activation on AT metabolism remain unclear. Since excess fat mobilization is considered an important primary event contributing to the onset of insulin resistance, we combined in vivo and in vitro experiments to investigate whether activation of ECS could alter the lipolytic rate. For this purpose, the appearance of plasma glycerol was measured in wild-type and CB1R−/− mice after acute anandamide administration or inh…
Association of liver steatosis with lipid oversecretion and hypotriglyceridaemia in C57BL/6j mice fed trans-10, cis-12-linoleic acid
2003
AbstractConjugated linoleic acids (CLA) have recently been recognized to reduce body fat and plasma lipids in some animals. This study demonstrated that the steatosis accompanying the fat loss induced by trans-10,cis-12-C18:2 (CLA2) and not cis-9,trans-11-C18:2 (CLA1) isomer in C57BL/6j mice was not due to an alteration of the liver lipoprotein production that was even increased. The 3-fold decrease in plasma triacylglycerol contents and the induction of mRNA expression of low-density lipoprotein receptors concomitantly observed in CLA2-fed mice suggested an increase in the lipoprotein clearance at the level of the liver itself. CLA1 feeding produced similar but attenuated effects on trigly…
Influence of the structures of ionic liquids on Hantzsch ester synthesis
2015
Maģistra darbā pētīta sakarība starp jonu šķidrumu struktūrām un Hanča estera sintēžu iznākumiem, tās veicot šajos jonu šķidrumos un lietojot urotropīnu kā reaģentu amonjaka un formaldehīda vietā. Sintezēti un raksturoti piecpadsmit šim pētījumam vajadzīgie jonu šķidrumi. Tie satur katjonus un anjonus ar mērķtiecīgi izmainītām struktūrām, lai varētu novērtēt šo jonu šķidrumu hidrofobo, ūdeņraža saišu donora-akceptora un elektrostatisko ietekmi uz pētīto Hanča estera sintēzes rezultātu. Šajā pētījumā ir salīdzināti alifātiskie un aromātiskie katjoni un anjoni, kā arī apspriesta jonu šķidrumu katalītiskā iedarbība salīdzinājumā ar to šķīdinātāja efektu. Darbā ir demonstrēta papildus katalizat…
Androgēnie anaboliskie steroīdi, to ietekme uz veselību un izplatība sabiedrības vidū
2016
Ārējais izskats spēj ietekmēt apkārtējo sabiedrības viedokli, veidojot priekšstatu par cilvēka raksturu un spējām. Izsenis cilvēkus ieinteresējis, kā izmantojot mazāku piepūli iegūt pievilcīgāku ķermeņa izskatu un labāku sportisko sniegumu. Lai sasniegtu mērķi cilvēki dažkārt ir gatavi izmēģināt visdažādākos līdzekļus, lai gan tiem ir risks pasliktināt veselību un izraisīt nopietnas blakusparādības. Šī darba mērķis bija noskaidrot, vai Latvijā ir izplatīta androgēno anabolisko steroīdu lietošana, kādi ir to lietošanas paradumi un, kurš no testosterona līdzekļiem BENU aptieku tīklā ir vispieprasītākais laika posmā no 2013. gada 1. janvāra līdz 2015. gada 31. decembrim. Pēc iegūtajiem aptauju…
Olen ylpeä puhallinorkkataustastani : Rantasalmen puhallinorkesteri 1979-2009
2011
Tutkimuksessa tarkasteltiin Rantasalmen puhallinorkesterin toimintaa sen 30‐vuotisen historian ajalta. Tarkoituksena oli selvittää, miten puhallinorkesteri on kehittynyt ja millaista sen toiminta on ollut vuosien saatossa. Olennaisessa osassa tutkimusta olivat yksilöiden tuntemat kokemukset ja niiden kautta syntyneet merkitykset koskien ympäröivää yhteisöä. Teoria- ja taustaosuudessa tavoiteltiin aikaisempien tutkimusten ja kirjallisuuden pohjalta tietoa kulttuurin ja yhteisön määrittelystä, soittamisesta harrastuksena sekä hankittiin lisätietoa kansalaisopistoista taiteenperusopetuksen organisaationa. Tutkimusaineisto koostui dokumenteista, kapellimestarien haastatteluista sekä entisten ja…