Search results for "characterization"

Composition of mosses, their metabolites and environmental stress impacts

2018

Sūnas ir nozīmīga augu grupa ar plašu izplatību. Sūnu sastāva pētījumi ir kļuvuši aktuāli, ņemot vērā bioloģiski aktīvu savienojumu klātbūtni un augsto izturību pret vides apstākļu mainību. Promocijas darba mērķis ir analizēt sūnu sastāvu, to metabolītus un vides stresa ietekmes uz tiem. Veikta sūnu sekundāro metabolītu ekstrakcijas apstākļu izpēte, kas nodrošina liela skaita vielu identifikāciju. Sūnu lipīdi satur daudzas bioloģiski aktīvas vielas un veikta to aktivitātes izpēte. Sūnu sekundārie metabolīti uzrāda augstu antimikrobiālo aktivitāti un spējas inhibēt vairāku vēža šūnu līniju attīstību un līdz ar to satur perspektīvas vielu grupas izmantošanai biomedicīnā. Vides stresa ietekmes…

2019

Ultrasound tissue characterization (UTC) imaging has been previously used to describe the characteristics of patellar and Achilles tendons. UTC imaging compares and correlates successive ultrasonographic transverse tendon images to calculate the distribution of four color-coded echo-types that represent different tendon tissue types. However, UTC has not been used to describe the characteristics of patellar tendons after anterior cruciate ligament reconstruction (ACLR). The aim of this cross-sectional study was to assess the intra and inter-rater reliability of the UTC in unharvested and harvested patellar tendons of patients undergoing ACLR. Intra and inter-rater reliability of both UTC da…

Dynamic Functional Connectivity in the Musical Brain

2019

Musical training causes structural and functional changes in the brain due to its sensory-motor demands. This leads to differences in how musicians perceive and process music as compared to non-musicians, thereby providing insights into brain adaptations and plasticity. Correlational studies and network analysis investigations have indicated the presence of large-scale brain networks involved in the processing of music and have highlighted differences between musicians and non-musicians. However, studies on functional connectivity in the brain during music listening tasks have thus far focused solely on static network analysis. Dynamic Functional Connectivity (DFC) studies have lately been …

Nanostructured products applications for the conservation of Cultural Heritage samples

2012

Optical and structural properties of Al 2 O 3 /ZnO nanolaminates deposited by ALD method

2014

International audience; We report on the investigation of optical and structural properties of Al2O3/ZnO nanolaminates. The nanolaminates were deposited on Si and glass substrates by Atomic layer deposition method. Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence spectroscopy. Complex analysis of monolayer properties was done by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated.

Assouad Type Dimensions in Geometric Analysis

2021

We consider applications of the dual pair of the (upper) Assouad dimension and the lower (Assouad) dimension in analysis. We relate these notions to other dimensional conditions such as a Hausdorff content density condition and an integrability condition for the distance function. The latter condition leads to a characterization of the Muckenhoupt Ap properties of distance functions in terms of the (upper) Assouad dimension. It is also possible to give natural formulations for the validity of Hardy–Sobolev inequalities using these dual Assouad dimensions, and this helps to understand the previously observed dual nature of certain cases of these inequalities. peerReviewed

Application of Broadband Dielectric Spectroscopy to Cultural Heritage: characterization and preservation of ancient paper artwork

2016

Within the cultural heritage the characterization and conservation of artworks based on paper represents a significant issue for both restorers and scientists. The paper deterioration is affected by the degree of hydrolytic and oxidative reactions which occur upon aging. Moreover, the durability of cellulose fibers depends on the intrinsic composition/structure of the paper as well as on the conservation conditions, such as temperature and humidity. The structural and dynamical characterization of the cellulose matrix and of the water confined within its pores is therefore of central interest. Our working hypothesis is that WATER DYNAMICS is one of the main determinants of paper degradation…

Electro-optical characterization of highly efficient Dye-Sensitized solar cells

2015

Nowadays, a growing demand for free and clean energy requires the study and the development of new low-cost solar photovoltaic (PV) cells. Among them, Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes as sensitizers are assuming a great importance. The DSSCs under study are composed placing in succession a transparent conductive glass on which is screen-printed a mesoporous TiO2 thin film sensitized by a ruthenium based dye (N719), an electrolytic solution containing a redox couple (I-/I3-) and another conductive glass covered by a thin transparent catalyst platinum film. In this work, we have measured the main photoelectrochemical parameters of the above mentioned DSSCs at di…

Plasma Dynamics Characterization for Improvement of Resonantly Enhanced Harmonics Generation in Indium and Tin Laser-Produced Plasmas

2022

R.A.G. is grateful to H. Kuroda for providing the access to the laser facility. As a Center of Excellence, the Institute of Solid State Physics at the University of Latvia received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement no. 739508, project CAMART².

Characterization of thin plastic foils for applications in X-ray optics technology

2007

Thin plastic foils are being investigated to build shell optics for X-ray telescopes. Compared to polished glass optics, the advantage is in terms of increased collecting area, light weight and lower cost. Plastic material is also desirable to allow deformation into a complete surface of revolution. We collected plastic materials of common use for industrial applications and also specialty materials developed for the electronic industry. A comparative study was then performed to evaluate the optical quality of the selected plastic films. Surface analysis was carried out with topographic instruments to investigate the microroughness of our samples at different scan lengths. Preliminary resul…