Search results for "LOD"
showing 10 items of 4833 documents
Vēstures un filoloģijas zinātnes, 1. sērija
1956
Opijs - Ķīnas impērijas un Ķīnas sabiedrības transformācijas cēlonis 18.-20.gs.
2019
Maģistra darbs „Opijs – Ķīnas impērijas un Ķīnas sabiedrības transformācijas cēlonis 18.-20.gs.” ir veltīts opija lietošanas problemātikai un tā ietekmei uz sabiedrību, kā arī valsts transformācijai opija dēļ. Konkrēti tiek pētīta opija ietekme uz sociālo dzīvi Ķīnā, kā arī tas, kā opijs ietekmēja uz Ķīnas attiecībām ar citām valstīm. Tēmas aktualitāte tiek balstīta uz to, ka opijs pilnībā pārveidoja Ķīnas sociālo dzīvi, un arī pārveidoja pašu valsti. Kaut gan opija problēma mūsdienu Ķīnā vairs nepastāv, tā tomēr ir neatņemama vēstures un līdz ar to arī valsts kultūras sastāvdaļa un ir atstājusi zināmas sekas arī uz moderno Ķīnas sabiedrību. Darba mērķis bija: izpētīt izmaiņas Ķīnas sabiedr…
Skatiena veidi „Marvel” filmu pasaulē
2015
Marvel filmu pasaule ir unikāls koncepts, kas saista 11 dažādas filmas, kuras visas ir daļa no vienotas pasaules, kurā notikumi vienā filmā ietekmē notikumu attīstību citās. Lai radītu vienotas pasaules sajūtu, filmās ir jābūt aspektiem, kas eksistē kā vienojošas saites un kuriem ir jābūt visas filmās; šajā darbā tiek pētīts tas, vai un kā skatiens tā dažādajās formās spēlē lomu šajā procesā. Skatiens ir bijis vairāku pētnieku uzmanības centrā, un Lakāna skatiena koncepts ir visbiežāk pielietots filmu teorijā. Veiktā analīze liecina, ka vīrieša skatiena izpausmes ir novērojamas visās filmās, arī citi skatiena veidi, piemēram, postkoloniālais, ir novērojami vairāk nekā vienā filmā. Taču katr…
Inclusion complexes of triblock L35 copolymer and hydroxyl propyl cyclodextrins: a physico-chemical study
2022
In this work, we studied the formation of supramolecular inclusion complexes (pseudopolyrotaxanes) generated by the interactions between L35 Pluronic (PEO-PPO-PEO triblock copolymer) and hydroxyl propyl-modified cyclodextrins (HP-alpha-CD and HP-beta-CD). The structural characteristics of the L35/CD composites were investigated by X-ray diffraction spectroscopy, which highlighted the effective inclusion of the copolymer. The thermodynamic properties of the pseudopolyrotaxanes were determined through density and speed of sound experiments conducted on aqueous mixtures with various L35/CD compositions, while turbidimetric analyses allowed the investigation of the kinetics of the threading pro…
Hyaluronic acid and beta cyclodextrins films for the release of corneal epithelial cells and dexamethasone
2016
In this work we prepared hydrogels based on hyaluronic acid and β-cyclodextrins to sustain the release of both corneal epithelial cells and dexamethasone. This steroid is administered as eye drops several times per day to reduce the risk of rejection in the post operative period after the cornea transplantation and cell release techniques. Hydrogels were produced by crosslinking an amino derivative of hyaluronic acid, with the divinyl sulfone derivative of β-cyclodextrins, this last employed as a crosslinker and solubilizing agent. Drug release studies revealed that dexamethasone containing samples are able to extend the release of this drug for at least five days. Biological studies, condu…
Robust Mesoporous CoMo/γ-Al2O3 Catalysts from Cyclodextrin-Based Supramolecular Assemblies for Hydrothermal Processing of Microalgae: Effect of the P…
2018
Hydrothermal liquefaction (HTL) is a promising technology for the production of biocrude oil from microalgae. Although this catalyst-free technology is efficient under high-temperature and high-pressure conditions, the biocrude yield and quality can be further improved by using heterogeneous catalysts. The design of robust catalysts that preserve their performance under hydrothermal conditions will be therefore very important in the development of biorefinery technologies. In this work, we describe two different synthetic routes (i.e., impregnation and cyclodextrin-assisted one-pot colloidal approach), for the preparation in aqueous phase of six high surface area CoMo/γ-Al2O3 catalysts. Cat…
Multicavity halloysite-amphiphilic cyclodextrin hybrids for co-delivery of natural drugs into thyroid cancer cells
2015
Multicavity halloysite nanotube materials were employed as simultaneous carriers for two different natural drugs, silibinin and quercetin, at 6.1% and 2.2% drug loadings, respectively. The materials were obtained by grafting functionalized amphiphilic cyclodextrin onto the HNT external surface. The new materials were characterized by FT-IR spectroscopy, SEM, thermogravimetry, turbidimetry, dynamic light scattering and ζ-potential techniques. The interaction of the two molecules with the carrier was studied by HPLC measurements and fluorescence spectroscopy, respectively. The release of the drugs from HNT-amphiphilic cyclodextrin, at two different pH values, was also investigated by means of…
Copolymer−Cyclodextrin Inclusion Complexes in Water and in the Solid State. A Physico-Chemical Study
2008
The formation of inclusion complexes (ICs) composed of cyclodextrins (CDs) and poly(ethylene oxides)-poly(propylene oxides)-poly(ethylene oxides) (PEO-PPO-PEO) was studied. To this purpose, native and hydroxypropyl cyclodextrins with different cavity size were chosen. The PEO-PPO-PEO copolymers were selected to study the role of the molecular weight, keeping constant the hydrophilic/hydrophobic ratio, and the hydrophilicity. The volumetric studies at 25 degrees C allowed to determine the equilibrium constant and the volume change for the IC formation in water as well as the IC stoichiometry. Surface tension experiments evidenced that the copolymer and the CD interfacial behavior is controll…
Molecular Scale Study of Domain Boundaries and Frictional Stick-Slip Motion on Lipid Bilayers
1995
A highly 2-dimensional (2D) anisotropic crystal formation of an organic one component lipid bilayer system is presented measured in air by atomic force microscopy. 2D domains with different crystal orientation could be observed. Their molecularly smooth domain boundaries are perceived to be either commensurable or incommensurable lattice joints. Differences in the orientation of the crystal lattice affects dynamic friction on the micrometer scale. High resolution friction images provide stick-slip motions depending on the scan direction in respect to the lattice orientation. It is shown that sliding friction can be determined by an averaged value of the molecular stick-slip motion of the fr…