Search results for "Lene"
showing 10 items of 4480 documents
Tīklenes nervu škiedru slāņa un ganglionāro šūnu slāņa izmeklēšana pacientiem ar miopiju, izmantojot optisko koherento tomogrāfiju
2018
Ievads: Tuvredzība ir viens no galvenajiem redzes pasliktināšanās cēloņiem pasaulē. Aksiālās acs elongācijas dēļ rodas vairākas pārmaiņas tīklenes struktūrā: samazinās ganglionāro šūnu slāņa (GŠS) biezums un tīklenes nervu šķiedru slāņa (TNŠS) biezums. Pateicoties optiskajai koherentajai tomogrāfijai (OKT), mūsdienās ir iespēja izvērtēt tuvredzīgas acs strukturālās īpatnības. Pētījuma mērķis: Izvērtēt tīklenes GŠS un TNŠS vidējā biezuma izmaiņas pacientiem ar stabilu dažādas pakāpes miopiju, izmantojot optiskās koherentās tomogrāfijas metodi. Analizējot iegūtos datus, identificēt faktorus, kas var veicināt šādas izmaiņas tīklenes un redzes nerva struktūrā miopiskiem pacientiem. Noteikt tīkl…
Third order nonlinear optical properties of novel TetrathiafulvalenePhenanthroline based dyads
2011
The non-linear optical properties of π-conjugated organic molecules such as TTF and their derivatives have recently gained particular interest due to their extended π-system and the strong electron donating character. The knowledge of the nonlinear optical response, as well as the impact of the charge transfer on the nonlinearity is very important. As such systems can be used in a variety of applications. In this study we investigate the nonlinear absorption of novel tetrathiafulvalene-phenanthroline based dyads by means of the Z-scan technique.
Ferulago nodosa Subsp. geniculata (Guss.) Troia & Raimondo from Sicily (Italy): Isolation of Essential Oil and Evaluation of Its Bioactivity
2020
Ferulago nodosa (L.) Boiss. (Apiaceae) is a species occurring in the Balkan-Tyrrhenian area. The object of the present study is Sicilian F. nodosa subsp. geniculata (Guss.) Troia & Raimondo, classified as an endemic F. nodosa subspecies. Aerial parts of this plant species were subjected to hydrodistillation to obtain an essential oil. A total of 93 compounds were identified with 2,3,6-trimethyl benzaldehyde (19.0%), spathulenol (9.0%), (E)-caryophyllene (5.4%), and caryophyllene oxide (5.4%) as the main components. The biological activities of F. nodosa essential oil were also investigated. This oil showed an interesting antioxidant potential in a 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sul…
Korelācija starp obstruktīvās miega apnojas sindromu un nearterītisku išēmisku priekšējo optisko neiropātiju
2021
Darba mērķis: Novērtēt obstruktīvās miega apnojas sindroma (OSAS) pacientus uz nearterītisku išēmisku priekšējo optisko neiropātiju (NAION). Novērtēt OSAS saistību ar peripapilārās tīklenes nervu šķiedru slāni (RNFL) un peripapilāro ganglionāro šūnu slāni-iekšējo tīklaino slāni (GCL-IPL). Metode: RNFL un GCL-IPL mērījumi tika veikti ar OCT. Rezultāti tika salīdzināti starp kontroles un OSAS grupām. Rezultāti: Nevienam no dalībniekiem netika atrasts NAION. Starp pētāmo grupu peripapilārā RNFL vai GCL-IPL biezumu netika novērota statistiska nozīme (p>0,05). Korelācija netika novērota starp AHI un RNFL vai GCL-IPL biezumu. Secinājumi: Peripapilārā RNFL un GCL-IPL neuzrādīja nozīmīgu atšķirību …
Šaka-Hartmana aberometrijas izmantošana tīklenes biezuma mērīšanai in vivo
2018
Darbs uzrakstīts latviešu valodā uz 30 lappusēm, satur 26 attēlus, 3 pielikumu, 24 atsauces uz literatūras avotiem. Darba mērķis: izpētīt Šaka- Hartmana aberometrijas pielietojumu tīklenes biezuma mērījumiem. Pētījuma dalībnieki: 10 cilvēki. Vidējais vecums 24,3 +/- 4,37 gadi (diapazons, 20- 35 gadi). Nevienam no pētījuma dalībniekiem nav konstatētas acu slimības vai sistēmiskas saslimšanas, kam ir ietekme uz refrakciju. Metode: ar Šaka- Hartmana aberometriju tika mērīts tīklenes biezums. Daļa rezultātu tika salīdzināti ar okulokoherento tomogrāfiju. Tika noskaidrots arī tīklenes fantoma biezums. Secinājumi: Šaka- Hartmana un OCT iegūto tīklenes biezumu vidējo rezultātu starpība ir 161 µm +…
Hyaluronan Graft Copolymers Bearing Fatty-Acid Residues as Self-Assembling Nanoparticles for Olanzapine Delivery
2019
In order to evaluate the potential of a technology platform based on hyaluronan copolymers grafted with propargylated ferulate fluorophores (HA-FA-Pg) in the development of drug delivery systems, the propargyl groups of HA-FA-Pg derivatives were employed with oleic acid (OA) or stearic acid (SA) residues across a biocompatible hexa(ethylene glycol) (HEG) spacer. The designed materials (i.e., HA-FA-HEG-OA or HA-FA-HEG-SA) showed clear-cut aggregation features in an aqueous environment, as confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM), generating nanoaggregate systems. In fact, HA-FA-HEG-OA and HA-FA-HEG-SA derivatives showed the property to create sel…
New charge transfer salts of two organic π-donors of the tetrathiafulvalene type with the paramagnetic [Cr(NCS)6]3- anion
2003
cited By 9; International audience; The electrochemical combination of the paramagnetic anion [Cr(NCS)6]3- with the organic π-donors bis(ethylenedithio)tetrathiafulvalene (ET) and 4,5-bis(2-hydroxyethylthio) -4′,5′-ethylenedithiotetrathiafulvalene (DHET-EDTTTF) leads to two new radical cation salts, namely (ET)4 [Cr(NCS 6]·PhCN 1 and (DHET-EDTTTF)2 (NEt4)[Cr(NCS)6] 2. Both have been characterized by X-ray crystallography, magnetic and resistivity measurements. The structure of 1 consists of alternating inorganic layers generated by the anions and organic layers in which the PhCN molecules are inserted; the organic sub-lattice is built up from four different ET units, three of them with a ch…
One-pot cross-enyne metathesis (CEYM)-Diels-Alder reaction of gem-difluoropropargylic alkynes.
2013
Propargylic difluorides 1 were used as starting substrates in a combination of cross-enyne metathesis and Diels–Alder reactions. Thus, the reaction of 1 with ethylene in the presence of 2nd generation Hoveyda–Grubbs catalyst generates a diene moiety which in situ reacts with a wide variety of dienophiles giving rise to a small family of new fluorinated carbo- and heterocyclic derivatives in moderate to good yields. This is a complementary protocol to the one previously described by our research group, which involved the use of 1,7-octadiene as an internal source of ethylene.
Reactions of m-Terphenyl-Stabilized Germylene and Stannylene with Water and Methanol: Oxidative Addition versus Arene Elimination and Different React…
2015
Reactions of the divalent germylene Ge(ArMe6)2 (ArMe6 = C6H3-2,6-{C6H2-2,4,6-(CH3)3}2) with water or methanol gave the Ge(IV) insertion product (ArMe6)2Ge(H)OH (1) or (ArMe6)2Ge(H)OMe (2), respectively. In contrast, its stannylene congener Sn(ArMe6)2 reacted with water or methanol to produce the Sn(II) species {ArMe6Sn(μ-OH)}2 (3) or {ArMe6Sn(μ-OMe)}2 (4), respectively, with elimination of ArMe6H. Compounds 1–4 were characterized by IR and NMR spectroscopy as well as by X-ray crystallography. Density functional theory calculations yielded mechanistic insight into the formation of (ArMe6)2Ge(H)OH and {ArMe6Sn(μ-OH)}2. The insertion of an m-terphenyl-stabilized germylene into the O–H bond was…
Preparation of a Series of “Ru(p-cymene)” Complexes with Different N-Heterocyclic Carbene Ligands for the Catalytic β-Alkylation of Secondary Alcohol…
2008
A series of five different “(p-cymene)Ru(NHC)” complexes (NHC = imidazolin-2-ylidene, imidazolin-4-ylidene, and pyrazolin-3-ylidene) have been obtained and fully characterized. The crystal structure of two of the new complexes has been determined by X-ray diffraction methods. All five complexes have been tested in the catalytic β-alkylation of secondary alcohols with primary alcohols and the dimerization of phenylacetylene, showing an excellent activity in both processes. A clear improvement on the catalytic activity of the complexes is observed when the more basic NHC ligands are used. The pyrazolylidene-Ru complex lies among the best catalysts for the β-alkylation of secondary alcohols re…