Search results for "Fluorescence"
showing 10 items of 2463 documents
Kalcīts un tā veidošanās apstākļi augšējā devona Daugavas svītas dolomītos Latvijas centrālajā un austrumu daļā
2017
Bakalaura darbā “Kalcīts un tā veidošanās apstākļi augšējā devona Daugavas svītas dolomītos Latvijas centrālajā un austrumu daļā” ir raksturotas minerāla kalcīta fizikālās īpašības, mikroelementu saturs un veidošanās apstākļi. Pētījumi veikti 8 dolomīta atradnēs; ģeoloģiskajā griezumā un atradņu teritorijā salīdzinātas kalcīta īpašības. Testētas kalcīta fluorescences izpausmes, pētīti plānslīpējumi, raksturoti kalcītā sastopamie mikroelementi un oglekļa stabilo izotopu attiecības tajā. Secināts, ka kalcīts kristalizējies no atmosfēras ūdeņiem sauszemes apstākļos. Šis minerāls veidojies paleokarsta procesa beigu stadijā pēc iegruvumu izveidošanās. Atslēgas vārdi: mineraloģija, paleokarsts, f…
An Emulator Toolbox to Approximate Radiative Transfer Models with Statistical Learning
2015
Physically-based radiative transfer models (RTMs) help in understanding the processes occurring on the Earth’s surface and their interactions with vegetation and atmosphere. When it comes to studying vegetation properties, RTMs allows us to study light interception by plant canopies and are used in the retrieval of biophysical variables through model inversion. However, advanced RTMs can take a long computational time, which makes them unfeasible in many real applications. To overcome this problem, it has been proposed to substitute RTMs through so-called emulators. Emulators are statistical models that approximate the functioning of RTMs. Emulators are advantageous in real practice because…
Analysis of the impact of sex and age on the variation in the prevalence of antinuclear autoantibodies in Polish population: a nationwide observation…
2022
AbstractThe detection of antinuclear autoantibody (ANA) is dependent on many factors and varies between the populations. The aim of the study was first to assess the prevalence of ANA in the Polish adult population depending on age, sex and the cutoff threshold used for the results obtained. Second, we estimated the occurrence of individual types of ANA-staining patterns. We tested 1731 patient samples using commercially available IIFA using two cutoff thresholds of 1:100 and 1:160. We found ANA in 260 participants (15.0%), but the percentage of positive results strongly depended on the cutoff level. For a cutoff threshold 1:100, the positive population was 19.5% and for the 1:160 cutoff th…
Substrāta un organiskā mēslojuma ietekme uz Dracocephalum moldavica augu augšanu un fizioloģisko stāvokli
2019
Darba mērķis bija novērtēt dažādu substrātu un mēslošanas līdzekļu ietekmi uz augu augšanu, attīstību un to fizioloģiskajiem parametriem. Pētījumu veica ar Moldāvijas pūķgalvi, novērtējot substrātu, mēslojuma veidu un to koncentrāciju ietekmi uz augu augšanu un fizioloģiskajiem procesiem tajos. Augus audzēja veģetācijas traukos, kur par substrātu izmantoja kūdru vai melnzemi, kam pievienoja dažādus mēslojumus: mikrobioloģisko mēslojumu “Biomikss”, minerālo mēslojumu “Kristalon”, kā arī 20% vermikompostu un 30% vermikompostu. Secināja, ka vermikomposta pievienošana substrātam būtiski uzlabo augu augšanu un attīstību, to vitalitāti, kā arī šiem variantiem uzrādīja augstāko substrāta sāļu konc…
Mechanisms of cell death in canine parvovirus-infected cells provide intuitive insights to developing nanotools for medicine
2010
Jonna Nykky, Jenni E Tuusa, Sanna Kirjavainen, Matti Vuento, Leona GilbertNanoscience Center and Department of Biological and Environmental Science, University of Jyväskylä, FinlandAbstract: Viruses have great potential as nanotools in medicine for gene transfer, targeted gene delivery, and oncolytic cancer virotherapy. Here we have studied cell death mechanisms of canine parvovirus (CPV) to increase the knowledge on the CPV life cycle in order to facilitate the development of better parvovirus vectors. Morphological studies of CPV-infected Norden laboratory feline kidney (NLFK) cells and canine fibroma cells (A72) displayed characteristic apoptotic events. Apoptosis was f…
Diurnal Cycle Relationships between Passive Fluorescence, PRI and NPQ of Vegetation in a Controlled Stress Experiment
2017
In order to estimate vegetation photosynthesis from remote sensing observations; some critical parameters need to be quantified. From all absorbed light; the plant needs to release any excess that is not used for photosynthesis; by non-photochemical quenching; by fluorescence emission and unregulated thermal dissipation. Non-photochemical quenching (NPQ) processes are controlled photoprotective mechanisms which; once activated; strongly control the dynamics of photochemical efficiency. With illumination conditions increasing and decreasing during a diurnal cycle; photoprotection mechanisms needs to change accordingly. The goal of this work is to quantify dynamic NPQ; measured from active fl…
Pulsējošā elektromagnētiskā un gaismas starojuma ietekme uz baktēriju dzīvotspēju
2020
Baktēriju augšanu ir iespējams ietekmēt ar elektromagnētisko starojumu. Šī darba mērķis bija pētīt Escherichia coli un Staphylococus aureus kultūru dzīvotspēju pulsējošā elektromagnētiskā un gaismas starojuma ietekmē, vadoties pēc R. R. Raifa izstrādātās mikroorganismu nāvējošās oscilācijas hipotēzes. Šim nolūkam tika replicēta R.R. Raifa elektromagnētiskā starojuma ierīce, kas apstaroja kultūras režīmos no 600 Hz līdz 1000 Hz laika periodā 10 sekundes. Dzīvotspēja tika noteikta, mikroskopējot un skaitot šūnas, kas tika iekrāsotas ar ThermoFisher LIVE/DEAD BacLight Bacterial Viability Kit. Tika noteiktas divas atšķirīgas baktericīdas frekvences – 800 Hz (E.coli) un 727 Hz (S.aureus), ar kur…
Substrate specificity screening of oat (Avena sativa) seeds aminopeptidase demonstrate unusually broad tolerance in S1 pocket.
2012
Aminopeptidases are proteolytic enzymes that remove one amino acid at a time from N-terminus of peptidic substrates. In plants, inhibitors of aminopeptidases can find potential applications in agriculture as herbicides. In this report we have used a library of fluorogenic derivatives of natural and unnatural amino acids for substrate specificity profiling of oat (Avena sativa) aminopeptidase. Interestingly, we have found that this enzyme recognizes effectively among the natural amino acids basic residues like Arg and Lys, hydrophobic Phe, Leu and Met, but also to some extent acidic residues Asp and Glu. In the case of unnatural amino acids hydrophobic residues (hPhe and hCha) and basic hArg…
Solvatochromic behaviour of new donor–acceptor oligothiophenes
2021
Oligothiophene derivatives play a central role in the formulation of materials used in devices in the field of organic electronics. In this work, we report the results of the study of UV-vis absorption and fluorescence spectra, in several solvents, of a series of oligothiophenes recently synthesized in our laboratory. The studied oligothiophenes present different structures due to several factors: the donor– acceptor (D–A) or acceptor–donor–acceptor (A–D–A) architecture, the number of thiophene rings in the backbone (ranging from three to eight), the number and position of solubilizing octyl chains in the backbone, and the type of acceptor moieties (from Knoevenagel condensation either with…
Design, Synthesis and Evaluation of Fluorescent Analogues of Abscisic Acid
2020
A fluorescent analogue of abscisic acid has been prepared by combining (S)‐abscisic acid (ABA) with nitrobenzoxadiazole (NBD) fluorophore using ethanol amine as a linker. Isomerization of the double bond at the side chain of abscisic acid happened during the synthesis. The resulting fluorophore analogues derived from both isomeric compounds entered cells suggesting a wide applicability of the ABA‐NBD conjugates as fluorescent probes to study ABA mechanism of action. The functional properties of the isomeric ABA‐NBD conjugates were tested in vitro, by measuring TNFα expression and nitrite concentration in LPS‐stimulated macrophages and compared with their non‐fluorescent ABA isomers. Rationa…