272 research outputs found
Performance of FBK high-density SiPMs in scintillation spectrometry
No full textThe aim of this work is to provide the characteristics of Fondazione Bruno Kessler (FBK) high-density SiPMs with an active area of 2.2x2.2 mm2 (15x15 μm2 single cell size) in gamma-ray spectrometry with LSO and CsI:Tl scintillators. The measurements presented in this work covered: measurements of the single photoelectron spectra, characteristics of the breakdown voltage versus temperature, verification of the excess noise factor, selection of the optimum operating voltage for energy resolution, verification of the linearity of the SiPM response for both used scintillators, verification of the number of photoelectrons and gamma-ray spectrometry for a wide range of X and gamma ray energies from 22.1 to 1408 keV. The results of energy resolution obtained with the FBK SiPMs readout and two different scintillators were compared to those obtained for the same scintillator with the XP2020Q PMT
Branchiobdella balcanica Moszynski 1937
No full text41. Branchiobdella balcanica Moszýnski, 1937 Material examined. L 2 : 22.06. 2008. (1 ind.). Previous records. Skadarsko jezero (lake) (Karaman S.M. 1970). Distribution in neighbouring Balkan countries. Serbia (no data), Macedonia (Fauna Europea 2004), Albania (no data), Bosnia and Herzegovina (no data), Croatia (Klobučar et al. 2006), Slovenia (Gelder et al. 1994). Distribution. Europe.Published as part of Šundić, Danijela, Radujković, Branko M. & Ćetković, Jasmina Krpo -, 2011, Catalogue of aquatic Oligochaeta (Annelida: Clitellata) of Montenegro, exclusive of Naidinae and Pristininae, pp. 1-25 in Zootaxa 2985 on page 17, DOI: 10.5281/zenodo.27835
Transformacja systemowa bylej NRD - oczekiwania a rzeczywistosc. Oceny procesu w literaturze niemieckiej
No full textIn this paper an attempt is made to outline the views on the transformation of the former GDR formulated in the German scientific literature. Due to the limited scope of the paper and the magnitude and complexity of the phenomena, discussion is limited to the most important and most controversial - according to the author - aspects around which discussions were held between leading economists from academia and politicians. The study starts with a brief introduction regarding the merits of the transformation of the economic order of the former GDR. Further outlines early assessments of the economic condition of Eastern Germany and ideas on eventual reunification of the country. Then, following, if possible, the chronological order, an overview is provided of the most important assessment about elements of a new order, such as the monetary union and the deregulation of prices, changes in the ownership structure, the creation of the institutional framework and the situation on the labor market and financial transfers. The main scientific method applied is analysis of literature, evaluation of official documents and historical analysis
The synthesis and characterization of diphenylacetylene containing ion channels
No full textThis Thesis presents the synthesis, characterization and mechanistic explorations into a series of diphenylacetylene-containing oligoester ion channels. Eighteen final compounds were synthesized and tested for ion transport activity utilizing both vesicle and planar bilayer assays. The oligomers varied in length, hydrophobicity and the nature of the aromatic moiety. Compounds incorporating a modified diphenylacetylene (‘Dip’), or a novel phenyl-extended fluorophore (‘Trip’) were made using a reliable, modular synthesis. The final compounds were prepared in a total of 5 to 11 steps from commercial materials in yields ranging from 10 to 40%.
The compounds’ activity varied considerably; both highly active and completely inactive compounds were discovered. The differences in activity are controlled by structure via the influence of structural variables on the aqueous phase aggregation and the ability of the compound to insert into the bilayer membrane. These structure-activity studies uncovered two highly-active ion transporters, HO2C-Hex-Dip-Hex-Hex-OH and –OPO32- (Hex = 6-hydroxyhexanoyl) which exhibited activity almost 10-fold higher than the fully-saturated oligoesters developed in previous work. In some cases, the transport activity is initially high but declines over a period of 20-30 minutes following compound addition. This suggests that the compound slowly transitions to an environment where it cannot form active channels.
In the bilayer clamp, a variety of behaviours including highly-conducting openings were observed. An apparent voltage-gated response was exhibited by one of the Trip compounds (HO2C-Trip-G(E3)-OH), a property rarely seen for synthetic ion channels.
The Dip and Trip molecules exhibited environment-sensitive fluorescence. The observed Dip excimer-like emission is the second reported instance of this in solution. The Trip compounds are solvatochromic; this property was used to infer their location in the membrane. Partitioning into the membrane was followed by a blue-shifting and increased intensity of the fluorescence emission for both series of compounds. For the Trip isomers, which are significantly more emissive than the Dip molecules, this enhancement in intensity could be visualized by eye.
For the Dip oligomers, the excimer emission is a broad band with variable shape and intensity; it is time-dependent under some conditions. The excimer emission has a sub-nanosecond lifetime in homogenous solution that is significantly prolonged in the presence of vesicle bilayers, in which a number of lifetimes could be detected. Both monomer and excimer emissions can be quenched by aqueous copper, the excimer emission is more efficiently quenched than is the monomer.
The photophysical characteristics of these molecules allowed for a variety of experiments designed to probe their membrane partitioning and localization behaviours. The results indicate the formation of a complex mixture of interconverting monomeric and aggregate species as the compounds move from water to the bilayer. The slow evolution of the mixture is consistent with the times noted for loss of membrane activity in transport assays. From these data a new model that describes the transport process is proposed. The key feature of this model is that transport must occur via a species that forms quickly upon the mixing of the components. Possible structures of the intermediates formed are discussed.Graduat
Temperature Dependence of CsI:Tl Scintillation Pulse Shapes from -183°C to +90°C Measured with a SiPM Readout
No full textA custom designed cryostat was constructed to
measure the response of a CsI:Tl scintillator in temperature
range from -183°C up to +90°C. The light readout was realized
using a SiPM developed by FBK in near ultraviolet high density
(NUV-HD) technology. The crystal and the SiPM were installed
on separated copper frames. The crystal was cooled down by
liquid nitrogen, while the SiPM was kept at temperature close to
room temperature. A separation of 1 mm was kept between the
crystal and the photodetector to ensure thermal isolation. The
temperature of the crystal could be varied by heaters on the
scintillator frame and was continuously monitored using a coil
shaped resistance thermometer. The CsI:Tl scintillation decay
profiles were recorded in the entire temperature range provided
by the cryostat
The statistics of fish echo traces - models and validation
No full textBeam pattern probability density function (PDF) plays important role in indirect fish target strength estimation methods as it constitutes the kernel of any form of a "single-beam integral equation" that should be solved for unknown target strength PDP. Typically, the beam pattern PDF is calculated under the assumption of uniform spatial distribution of fish targets in beam pattern cross-section. However, in some cases this assumption can not be justified due to fish or vessel movement, and different number of fish echoes in fish traces. In the paper, two different models of fish traces statistics were investigated: one assuming the vessel movement with stationary fish and the other with stationary vessel and moving fish. Both approaches were modelled numerically and later verified experimentally using data obtained from a dual-beam system
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