1,032 research outputs found
Improving the method of solar radiation durability determination of cable products
The authors suggest an extra physic-mechanical procedure to determine durability of cable goods to solar radiation exposure. The test check was carried out using the standard and the proposed procedures. The results of two tests were compared and analyzed. The use of the proposed technique allows improving the validity and reliability of the laboratory experiment conducted in a real production environment and exclude the low-quality cable items. The only disadvantage of the proposed technique is its labor intensiveness
Is flow velocity a significant parameter in flood damage modelling?
Flow velocity is generally presumed to influence flood damage. However, this influence is hardly quantified and virtually no damage models take it into account. Therefore, the influences of flow velocity, water depth and combinations of these two impact parameters on various types of flood damage were investigated in five communities affected by the Elbe catchment flood in Germany in 2002. 2-D hydraulic models with high to medium spatial resolutions were used to calculate the impact parameters at the sites in which damage occurred. A significant influence of flow velocity on structural damage, particularly on roads, could be shown in contrast to a minor influence on monetary losses and business interruption. Forecasts of structural damage to road infrastructure should be based on flow velocity alone. The energy head is suggested as a suitable flood impact parameter for reliable forecasting of structural damage to residential buildings above a critical impact level of 2 m of energy head or water depth. However, general consideration of flow velocity in flood damage modelling, particularly for estimating monetary loss, cannot be recommended
Is flow velocity a significant parameter in flood damage modelling?
Flow velocity is generally presumed to influence flood damage. However, this influence is hardly quantified and virtually no damage models take it into account. Therefore, the influences of flow velocity, water depth and combinations of these two impact parameters on various types of flood damage were investigated in five communities affected by the Elbe catchment flood in Germany in 2002. 2-D hydraulic models with high to medium spatial resolutions were used to calculate the impact parameters at the sites in which damage occurred. A significant influence of flow velocity on structural damage, particularly on roads, could be shown in contrast to a minor influence on monetary losses and business interruption. Forecasts of structural damage to road infrastructure should be based on flow velocity alone. The energy head is suggested as a suitable flood impact parameter for reliable forecasting of structural damage to residential buildings above a critical impact level of 2m of energy head or water depth. However, general consideration of flow velocity in flood damage modelling, particularly for estimating monetary loss, cannot be recommended
Species-Specific and Distance-Dependent Dispersive Behaviour of Forisomes in Different Legume Species
Forisomes are giant fusiform protein complexes composed of sieve element occlusion (SEO) protein monomers, exclusively found in sieve elements (SEs) of legumes. Forisomes block the phloem mass flow by a Ca2+-induced conformational change (swelling and rounding). We studied the forisome reactivity in four different legume species—Medicago sativa, Pisum sativum, Trifolium pratense and Vicia faba. Depending on the species, we found direct relationships between SE diameter, forisome surface area and distance from the leaf tip, all indicative of a developmentally tuned regulation of SE diameter and forisome size. Heat-induced forisome dispersion occurred later with increasing distance from the stimulus site. T. pratense and V. faba dispersion occurred faster for forisomes with a smaller surface area. Near the stimulus site, electro potential waves (EPWs)—overlapping action (APs), and variation potentials (VPs)—were linked with high full-dispersion rates of forisomes. Distance-associated reduction of forisome reactivity was assigned to the disintegration of EPWs into APs, VPs and system potentials (SPs). Overall, APs and SPs alone were unable to induce forisome dispersion and only VPs above a critical threshold were capable of inducing forisome reactions
Entwicklung hybrider Prozessketten aus additiver und konventioneller Fertigungstechnologie für die Kernfusion
Twin-plate Ice Nucleation Assay (TINA) with infrared detection for high-throughput droplet freezing experiments with biological ice nuclei in laboratory and field samples
For efficient analysis and characterization of biological ice nuclei under
immersion freezing conditions, we developed the Twin-plate Ice Nucleation Assay
(TINA) for high-throughput
droplet freezing experiments, in which the temperature profile and freezing
of each droplet is tracked by an infrared detector. In the fully automated
setup, a couple of independently cooled aluminum blocks carrying two 96-well
plates and two 384-well plates, respectively, are available to study ice
nucleation and freezing events simultaneously in hundreds of microliter-range
droplets (0.1–40 µL). A cooling system with two refrigerant
circulation loops is used for high-precision temperature control (uncertainty
< 0.2 K), enabling measurements over a wide range of temperatures
( ∼  272–233 K) at variable cooling rates (up to 10 K min−1).The TINA instrument was tested and characterized in experiments with
bacterial and fungal ice nuclei (IN) from Pseudomonas syringae (Snomax®) and Mortierella alpina, exhibiting freezing curves in good agreement with literature
data. Moreover, TINA was applied to investigate the influence of chemical
processing on the activity of biological IN, in particular the effects of
oxidation and nitration reactions. Upon exposure of
Snomax® to O3 and NO2, the cumulative
number of IN active at 270–266 K decreased by more than 1 order of
magnitude. Furthermore, TINA was used to study aqueous extracts of
atmospheric aerosols, simultaneously investigating a multitude of samples
that were pre-treated in different ways to distinguish different kinds of
IN. For example, heat treatment and filtration indicated that most
biological IN were larger than 5 µm. The results confirm that TINA is
suitable for high-throughput experiments and efficient analysis of
biological IN in laboratory and field samples.</p
Novel insights into the inhibition of symbiotic nitrogen fixation by dark chilling in soybean root nodules
Методичні рекомендації з дисципліни „Вступ до педагогічної майстерності” для студентів інституту заочно-дистанційної освіти освітньо-кваліфікаційний рівень „Магістр”
Мета вивчення дисципліни «Вступ до педагогічної майстерності»: сформувати у студентів уявлення професійну майстерність педагога з огляду на умови викладання у вищих та середніх навчальних закладах. Курс спрямовано на ознайомлення зі специфікою навчального і виховного процесу в сучасних закладах освіти, надання студентам систематизованих знань із теоретичних засад педагогічної майстерності та формування практичних умінь і навичок забезпечення ефективності педагогічної взаємодії
TrpC3 Regulates Hypertrophy-Associated Gene Expression without Affecting Myocyte Beating or Cell Size
Pathological cardiac hypertrophy is associated with an increased risk of heart failure and cardiovascular mortality. Calcium (Ca2+) -regulated gene expression is essential for the induction of hypertrophy, but it is not known how myocytes distinguish between the Ca2+ signals that regulate contraction and those that lead to cardiac hypertrophy. We used in vitro neonatal rat ventricular myocytes to perform an RNA interference (RNAi) screen for ion channels that mediate Ca2+-dependent gene expression in response to hypertrophic stimuli. We identified several ion channels that are linked to hypertrophic gene expression, including transient receptor potential C3 (TrpC3). RNAi-mediated knockdown of TrpC3 decreases expression of hypertrophy-associated genes such as the A- and B-type natriuretic peptides (ANP and BNP) in response to numerous hypertrophic stimuli, while TrpC3 overexpression increases BNP expression. Furthermore, stimuli that induce hypertrophy dramatically increase TrpC3 mRNA levels. Importantly, whereas TrpC3-knockdown strongly reduces gene expression associated with hypertrophy, it has a negligible effect on cell size and on myocyte beating. These results suggest that Ca2+ influx through TrpC3 channels increases transcription of genes associated with hypertrophy but does not regulate the signaling pathways that control cell size or contraction. Thus TrpC3 may represent an important therapeutic target for the treatment of cardiac hypertrophy and heart failure
Microbes Bind Complement Inhibitor Factor H via a Common Site
To cause infections microbes need to evade host defense systems, one of these being the evolutionarily old and important arm of innate immunity, the alternative pathway of complement. It can attack all kinds of targets and is tightly controlled in plasma and on host cells by plasma complement regulator factor H (FH). FH binds simultaneously to host cell surface structures such as heparin or glycosaminoglycans via domain 20 and to the main complement opsonin C3b via domain 19. Many pathogenic microbes protect themselves from complement by recruiting host FH. We analyzed how and why different microbes bind FH via domains 19–20 (FH19-20). We used a selection of FH19-20 point mutants to reveal the binding sites of several microbial proteins and whole microbes (Haemophilus influenzae, Bordetella pertussis, Pseudomonas aeruginosa, Streptococcus pneumonia, Candida albicans, Borrelia burgdorferi, and Borrelia hermsii). We show that all studied microbes use the same binding region located on one side of domain 20. Binding of FH to the microbial proteins was inhibited with heparin showing that the common microbial binding site overlaps with the heparin site needed for efficient binding of FH to host cells. Surprisingly, the microbial proteins enhanced binding of FH19-20 to C3b and down-regulation of complement activation. We show that this is caused by formation of a tripartite complex between the microbial protein, FH, and C3b. In this study we reveal that seven microbes representing different phyla utilize a common binding site on the domain 20 of FH for complement evasion. Binding via this site not only mimics the glycosaminoglycans of the host cells, but also enhances function of FH on the microbial surfaces via the novel mechanism of tripartite complex formation. This is a unique example of convergent evolution resulting in enhanced immune evasion of important pathogens viautilization of a “superevasion site.
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