Search results for "Fluorescence"
showing 10 items of 2463 documents
Vermikomposta ietekme uz K un NO3 jonu uzkrāšanos un fizioloģiskajiem parametriem kukurūzas augos
2017
Vermikomposts ir organisks mēslojums, ko arvien vairāk izmanto lauksaimniecībā augsnes mehānisko, fizikālo un ķīmisko īpašību uzlabošanai. Vermikomposts labvēlīgi ietekmē augu augšanu un attīstību, tomēr lai sasniegtu tā maksimālo efektivitāti, nepieciešams noskaidrot optimālās lietošanas koncentrācijas. Darba mērķis bija novērot vermikomposta ietekmi uz K+ un NO3- jonu uzkrāšanos un fizioloģiskajiem parametriem kukurūzas augos. Noteica fotosintēzi raksturojošos rādītājus, aprēķināja rezultātus, kas tika iegūti analizējot dažādus augu fizioloģiskos parametrus un noteica kālija un nitrātu uzkrāšanos kukurūzas augos. Pēc iegūtajiem datiem novēroja, ka vermikompostam ir labvēlīga ietekme uz fi…
Automated water quality monitoring of humic lakes by using the optical properties of water
2016
Automated water quality monitoring (AWQM) is becoming increasingly common in lakes worldwide. The history of AWQM is relatively short and standard calibration procedures for the measured variables are largely yet to be established. The use of optical AWQM sensors, developed in oceanic environments, raises new questions on the diverse effects which humic compounds may have on the automated optical measurements in inlands waters. The focus of this thesis was to characterize the effects of coloured dissolved organic matter (CDOM) on optical in situ measurements of organic matter (OM) and chlorophyll (Chl) in lakes with varying humic content, and to use AWQM data as a part of traditional monito…
Organiskā mēslojuma līdzekļu ietekme uz lapu dārzeņu un garšaugu fizioloģiju, augšanu un kvalitātes rādītājiem kontrolētos apstākļos
2018
Arvien vairāk tiek pielietotas bioloģiskās saimniekošanas metodes, kad barības vielas augiem nodrošina ar organiskas izcelsmes mēslojumu. Viena no organisko mēslošanas līdzekļu priekšrocībām ir tā, ka tiem ir salīdzinoši augsts barības vielu saturs, kas pieejamas augiem, bet nav skaidru ziņu par to, kā tie ietekmē dažādu dārzeņu sugu augšanu, attīstību un fotosintēzes procesus, pielietojot dažādas mēslojuma devas. Darba mērķis bija pārbaudīt dažādas koncentrācijas vermikomposta un komposta ietekmi uz garšaugu, lapu dārzeņu un ārstniecības augu ražu un kvalitāti. Eksperimentu ierīkoja Latvijas Universitātes Bioloģijas fakultātes Augu fizioloģijas katedrā, kontrolētos apstākļos no 2017. gada …
Multi-elemental EDXRF mapping of polluted soil from former horticultural land.
2004
The distribution of major and trace elements was systematically investigated by use of energy dispersive X-ray fluorescence spectrometry (EDXRF) on a former horticultural soil. The purpose of the study was to combine mapping of soil element concentration levels with multivariate statistics for characterisation of soil metal pollution in relation to previous and present land use. A 1-ha study site was chosen from a former horticulture where a previous preliminary survey indicated increased concentration levels of toxic elements. The soil was sampled from the top 20 cm of the soil surface in a 10×10-m grid-like pattern covering the 1-ha study area. In addition, three soil profiles were studie…
Spectrofluorimetric study of dissolved organic matter in River Salaca (Latvia) basin waters
2012
Dissolved organic matter (DOM) in surface waters influences mineral weathering, nutrient cycling, aggregation of particulate matter and photochemical reactions in waters and aquatic communities. In this study, the effectiveness of UV and fluorescence measurements in distinguishing the origin of DOM and processes within the river basin were analyzed using the River Salaca basin as an example. The basin of River Salaca is characterized by low anthropogenic pressure, however, the water color during the last few decades has increased (an effect known as brownification). As tools to study the composition of dissolved organic substances in waters of the River Salaca and its tributaries the use of…
Influence of Nanoparticle Exposure on Nervous System Development in Zebrafish Studied by Means of Light Sheet Fluorescence Microscopy
2016
Zebrafish has a remarkable similarity in the molecular signaling processes, cellular structure, anatomy and physiology to other higher order vertebrates, making it an excellent vertebrate model organism (1). Recently, zebrafish has been used for neurotoxicity screening of numerous nanomaterials with a focus on the developmental effects due to the possibility of in vivo visualization of specific neurons and axon tracts by injecting dyes in live animals as well in fixed ones (2). Here we propose Light Sheet Fluorescence Microscopy (LSFM) (3) (4) to perform neurotoxicity studies, in order to study the nervous system architecture and to image 3D structures in the brain of live larvae during the…
A Novel Fast Volumetric Light Sheet Microscopy
2016
Fast noninvasive three-dimensional (3D) imaging is crucial for the quantitative understanding of highly dynamic biological processes. Over the last decades, several fluorescence microscopy techniques have been developed in order to provide a faster and deeper imaging of thick biological samples [1]. Within this framework, Light Sheet Fluorescence Microscopy (LSFM) has emerged as a powerful imaging tool for 3D imaging of thick samples ranging from single cells to entire animals [2,3].However, to obtain a 3D reconstruction either sample or microscope parts usually need to be moved limiting the acquisition speed and inducing possible interferences in volume recording. To solve this problem, he…
Fluorescent Biosensors Based on Silicon Nanowires
2021
Nanostructures are arising as novel biosensing platforms promising to surpass current performance in terms of sensitivity, selectivity, and affordability of standard approaches. However, for several nanosensors, the material and synthesis used make the industrial transfer of such technologies complex. Silicon nanowires (NWs) are compatible with Si-based flat architecture fabrication and arise as a hopeful solution to couple their interesting physical properties and surface-to-volume ratio to an easy commercial transfer. Among all the transduction methods, fluorescent probes and sensors emerge as some of the most used approaches thanks to their easy data interpretation, measure affordability…
Microneedling dilates the follicular infundibulum and increases transfollicular absorption of liposomal sepia melanin
2015
Gabriel Serrano,1 Patricia Almudéver,2 Juan M Serrano,3 Julio Cortijo,2 Carmen Faus,1 Magda Reyes,1 Inmaculada Expósito,3 Ana Torrens,3 Fernando Millán1 1Clínica Dermatológica Serrano, 2Department of Pharmacology, University of Valencia, 3Research and Development Department, Sesderma Laboratories, Valencia, Spain Abstract: Encapsulation of chemicals in liposomes and microneedling are currently used techniques to enhance the penetration of several substances through skin and hair. In this study, we apply a liposomal melanin–fluorescein compound to an ex vivo model of human skin, using a new electrical microneedling device (Nano…
Apoptotic-like Leishmania exploit the host´s autophagy machinery to reduce T-cell-mediated parasite elimination
2015
Apoptosis is a well-defined cellular process in which a cell dies, characterized by cell shrinkage and DNA fragmentation. In parasites like Leishmania, the process of apoptosis-like cell death has been described. Moreover upon infection, the apoptotic-like population is essential for disease development, in part by silencing host phagocytes. Nevertheless, the exact mechanism of how apoptosis in unicellular organisms may support infectivity remains unclear. Therefore we investigated the fate of apoptotic-like Leishmania parasites in human host macrophages. Our data showed--in contrast to viable parasites--that apoptotic-like parasites enter an LC3(+), autophagy-like compartment. The compartm…