Search results for "DAS"
showing 10 items of 4164 documents
Ādas fulorescences un izkliedes kinētikas mērījumi pikosekunžu lāzera ierosmē
2017
Lai gan pirmajā acu uzmetienā ādas autofluorescence un starojuma izkliedes kinētikas ir it kā vienkāršas metodes vides pētīšanai un tās parametru noteikšanai, tieši tāpēc tās ir efektīvas. Izmantojot ādas veidojumu raksturošanai metodes, kas nav nepamatoti sarežģītas, iespējams iegūt lielumus, kas raksturo dažādas ādas pataloģijas. Fotonu uzvedības ādā apraksts ir svarīga sastāvdaļa optiskās diagnostikas attīstībai. Darbā tika pētīti ādas veidojumi, izmantojot autofluroescences mērījumus un fotona lidojuma laika ādā mērījumus. Tika iegūti vairāki parametri, ar ko raksturot dažādas ādas pataloģijas, kā arī apskatīta korelācija starp autofluroescenci un fotona lidojuma laika ādā raksturlielum…
Modulating activity of dietary flavonols and flavan-3ols on the enzymes xanthina oxidase (XO) and mitochondrial superoxide dismutase (Mn-SOD)
2012
Effects of naturally occurring dihydroflavonols from Inula viscosa on inflammation and enzymes involved in the arachidonic acid metabolism
2007
Abstract The anti-inflammatory properties of three flavanones isolated from Inula viscosa , sakuranetin, 7- O -methylaromadendrin, and 3-acetyl-7- O -methylaromadendrin, have been tested both in vitro and in vivo. Acute inflammation in vivo was induced by means of topical application of 12- O -tetradecanoylphorbol 13-acetate (TPA) to mouse ears or by subcutaneous injection of phospholipase A 2 (PLA 2 ) into mouse paws. The test compounds were evaluated in vitro for their effect on both the metabolism of arachidonic acid and on the release and/or activity of enzymes involved in the inflammatory response such as elastase, myeloperoxidase (MPO), and protein kinase C (PKC). The most active comp…
In-Gel Assay to Evaluate Antioxidant Enzyme Response to Silver Nitrate and Silver Nanoparticles in Marine Bivalve Tissues
2022
Silver is back in vogue today as this metal is used in the form of nanomaterials in numerous commercial products. We have developed in-gel electrophoretic techniques to measure the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX), and used the same techniques in combination with HSP70 Western blot analysis to evaluate the effects of nanomolar amounts of silver nitrate and 5 nm alkane-coated silver nanoparticles in tissues of the marine bivalve Mytilus galloprovincialis (Lam.) exposed for 28 days in mesocosms. Our results showed a negligible effect for nanosilver exposure and dose-dependent effects for the nitrate form.
Long- and short-term stability of all polarization-maintaining thulium doped passively mode-locked fiber lasers with emission wavelengths at 1.95 µm …
2023
In this work, we compare the operation of a passively modelocked polarization-maintaining emission in two thulium-doped fiber lasers pumped at 1561 nm, with emission at wavelengths of 1.951 μm in one case and 2.07 μm in the other. We obtained a sequence of light pulses at 15.6 MHz, whose temporal width was 81 ps at 1.95 μm, and a sequence of light pulses at 13.1 MHz, whose temporal width was 94 ps at 2.07 μm. Finally, we also measured the long-term stability of this setup during a 24-h operation, as well as the short-term stability in a simulated harsh environment. The results confirm the superior performance of fiber laser systems with a fully polarization-maintaining design.
Dual Enzyme-Responsive Capsules of Hyaluronic Acid-block-Poly(Lactic Acid) for Sensing Bacterial Enzymes.
2015
The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron…
Selective binding to monoamine oxidase A: in vitro and in vivo evaluation of (18)F-labeled β-carboline derivatives.
2015
In this study we synthesized four different (18)F-labeling precursors for the visualization of the monoamino oxidase A using harmol derivatives. Whereas two are for prosthetic group labeling using [(18)F]fluoro-d2-methyl tosylate and 2-[(18)F]fluoroethyl-tosylate, the other three precursors are for direct nucleophilic (18)F-labeling. Additionally the corresponding reference compounds were synthesized. The syntheses of [(18)F]fluoro-d2-methyl-harmol and 2-[(18)F]fluoroethyl-harmol were carried out using harmol as starting material. For direct nucleophilic (18)F-labeling of the tracers carrying oligoethyled spacers (PEG), a toluenesulfonyl leaving group was employed. The radiolabeling, purifi…
Montesori valodas materiāli fonētiski fonemātisko traucējumu korekcijā vecākā pirmsskolas vecuma bērniem
2021
Pētījuma darba autore – Zita Zariņa. Pētījuma darba nosaukums – Montesori valodas materiāli fonētiski fonemātisko traucējumu korekcijā vecākā pirmsskolas vecuma bērniem. Pētījuma mērķis – teorētiski izzināt un praktiskā darbībā pārbaudīt fonētiski fonemātisko traucējumu mazināšanu izmantojot Montesori valodas materiālus. Pētījuma teorētiskā daļa – darba autore pētījusi un analizējusi, dažādu autoru teorētiskās atziņas par vecākā pirmsskolas vecuma bērnu attīstību kopveselumā gan pie vecumposmam atbilstīgas attīstības, gan bērniem ar fonētiski fonemātiskajiem traucējumiem. Kā arī pētījusi un analizējusi dažādu autoru teorētiskās atziņas par fonētiski fonemātiskajiem traucējumiem, to cēloņiem…
Effect of freezing/thawing process in different sizes of blue fish in the Mediterranean through lysosomal enzymatic tests
2014
The assessment of freshness of different sizes of blue fish (Engraulis encrasicolus 12 cm, Sardina pilchardus 15 cm, Trachurus trachurus 40 cm, Scomber japonicus colias 60 cm) was carried out using non-conventional enzymatic methods. The activities of the three lysosomal enzymes (α-glucosidase (AG), β-galactosidase (B-GAL) and β-N-acetylglucosamidase (B-NA)) in extracts of blue fish muscle were measured over a period of 21 days of storage. A significant increase (p < 0.05) of AG activity was observed in all species, with a large increase seen after only one day of storage. B-NA activity increased slightly in sardines, horse mackerels and chub mackerel during frozen/thawed storage. Finally, …
Impact of Oral Microbiota on Flavor Perception: From Food Processing to In-Mouth Metabolization.
2021
International audience; Flavor perception during food intake is one of the main drivers of food acceptability and consumption. Recent studies have pointed to the oral microbiota as an important factor modulating flavor perception. This review introduces general characteristics of the oral microbiota, factors potentially influencing its composition, as well as known relationships between oral microbiota and chemosensory perception. We also review diverse evidenced mechanisms enabling the modulation of chemosensory perception by the microbiota. They include modulation of the chemosensory receptors activation by microbial metabolites but also modification of receptors expression. Specific enzy…