4,591 research outputs found
A new method for automatic Multiple Partial Discharge Classification
A new wavelet based feature parameter have been developed to represent the characteristics of PD activities, i.e. the wavelet decomposition energy of PD pulses measured from non-conventional ultra wide bandwidth PD sensors such as capacitive couplers (CC) or high frequency current transformers (HFCT). The generated feature vectors can contain different dimensions depending on the length of recorded pulses. These high dimensional feature vectors can then be processed using Principal Component Analysis (PCA) to map the data into a three dimensional space whilst the first three most significant components representing the feature vector are preserved. In the three dimensional mapped space, an automatic Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm is then applied to classify the data cluster(s) produced by the PCA. As the procedure is undertaken in a three dimensional space, the obtained clustering results can be easily assessed. The classified PD sub-data sets are then reconstructed in the time domain as phase-resolved patterns to facilitate PD source type identification. The proposed approach has been successfully applied to PD data measured from electrical machines and power cables where measurements were undertaken in different laboratories
Development of quartz fiber calorimetry
Embedding radiation hard (up to Gigarad levels) silica optical fibres into an absorber is proposed for applications in very forward LHC calorimeters. The shower particles produce Cherenkov light. The main advantages of this solution are the fast response (signal duration below 10 ns), transverse dimension of the visible energy of hadronic showers of the order of 1 cm, and insensitivity to radio- and neutron- activation. A comprehensive study of the performance of such detector is proposed
Ultrastructural and spectrophotometric study on the effects of putative triggers on aortic valve interstitial cells in in vitro models simulating metastatic calcification.
Metastatic calcification of cardiac valves is a common complication in patients affected by chronic renal failure. In this study, primary bovine aortic valve interstitial cells (AVICs) were subjected to pro-calcific treatments consisting in cell stimulation with (i) elevated inorganic phosphate (Pi = 3mM), in order to simulate hyperphosphatemic conditions; (ii) bacterial endotoxin lipopolysaccharide (LPS), simulating direct effects by microbial agents; and (iii) conditioned media (CM) derived from cultures of either LPS-stimulated heterogenic macrophages (commercial murine RAW264.7 cells) or LPS-stimulated fresh allogeneic monocytes/macrophages (bCM), simulating consequent inflammatory responses, alone or combined. Compared to control cultures, spectrophotometric assays revealed shared treatment-dependent higher values of both calcium amounts and alkaline phosphatase activity for cultures involving the presence of elevated Pi. Ultrastructurally, shared peculiar pro-calcific degeneration patterns were exhibited by AVICs from the same cultures irrespectively of the applied treatment. Disappearance of all cytomembranes and concurrent formation of material showing positivity to Cuprolinic Blue and co-localizing with silver precipitation were followed by the outcropping of such a material, which transformed in layers outlining the dead cells. Subsequent budding of these layers resulted in the formation of bubbling bodies and concentrically laminated calcospherulae mirroring those in actual soft tissue calcification. In conclusion, the in vitro models employed appear to be reliable tools for simulating metastatic calcification and indicate that hyperphosphatemic-like conditions could trigger valve calcification per se, with LPS and allogeneic macrophage-derived secretory products acting as possible calcific enhancers via inflammatory responses
Characterization of humic fractions in leachates from soil under organic and conventional management and their interactions with the root zone
Humic fractions were shown to be closely involved in gene expression
and promotion of different PM H+-ATPase isoforms, as well as in lateral root
development, indicating an enhanced nutrient absorption capacity of the plant
root system. HPLC-SEC confirmed that water-soluble humic substances (WSHS)
correspond to a subfraction of the fulvic fraction of humic substances. This was
supported by E465/E665 ratios higher than 8.5. These ratios generally increased over
the growing season in cultivated soils but showed significant differences between
conventionally and organically managed bare soils. FTIR data and the analytical
quantification of carboxyls confirmed relevant structural changes in bare soil under
both organic and conventional farming management. Absorption intensities ratios
at 1,590\u20131,570 cm-1 and 1,440\u20131,380 cm-1 showed the predominant aliphatic
character of these molecules
Survival-related autophagic activity versus procalcific death in cultured aortic valve interstitial cells treated with critical normophosphatemic-like phosphate concentrations
Valve dystrophic calcification is a common disorder affecting normophosphatemic subjects. Here, cultured aortic valve interstitial cells (AVICs) were treated 3 to 28 days with phosphate (Pi) concentrations spanning the normal range in humans (0.8, 1.3, and 2.0 mM) alone or supplemented with proinflammatory stimuli to assess possible priming of dystrophic-like calcification. Compared with controls, spectrophotometric analyses revealed marked increases in calcium amounts and alkaline phosphatase activity for 2.0-mM-Pi-containing cultures, with enhancing by proinflammatory mediators. Ultrastructurally, AVICs treated with low/middle Pi concentrations showed an enormous endoplasmic reticulum (ER) enclosing organelle debris, so apparently executing a survival-related atypical macroautophagocytosis, consistently with ultracytochemical demonstration of ER-associated acid phosphatase activity and decreases in autophagosomes and immunodetectable MAP1LC3. In contrast, AVICs cultured at 2.0-mM Pi underwent mineralization due to intracellular release and peripheral layering of phospholipid-rich material acting as hydroxyapatite nucleator, as revealed by Cuprolinic Blue and von Kossa ultracytochemical reactions. Lack of immunoblotted caspase-3 cleaved form indicated apoptosis absence for all cultures. In conclusion, fates of cultured AVICs were crucially driven by Pi concentration, suggesting that serum Pi levels just below the upper limit of normophosphatemia in humans may represent a critical watershed between macroautophagy-associated cell restoring and procalcific cell death
Characterization of humic fractions in leachates from soil under organic and conventional management and their interactions with the root zone
Humic fractions were shown to be closely involved in gene expression
and promotion of different PM H+-ATPase isoforms, as well as in lateral root
development, indicating an enhanced nutrient absorption capacity of the plant
root system. HPLC-SEC confirmed that water-soluble humic substances (WSHS)
correspond to a subfraction of the fulvic fraction of humic substances. This was
supported by E465/E665 ratios higher than 8.5. These ratios generally increased over
the growing season in cultivated soils but showed significant differences between
conventionally and organically managed bare soils. FTIR data and the analytical
quantification of carboxyls confirmed relevant structural changes in bare soil under
both organic and conventional farming management. Absorption intensities ratios
at 1,590–1,570 cm-1 and 1,440–1,380 cm-1 showed the predominant aliphatic
character of these molecules
The complexity of soil biological sustainability
Additions of organic amendments to soil not only compensate for decreased soil
C, but also contribute to energy requirements for conserving biological activity levels.
The soil microbial biomass displays some highly conserved, and possibly unique,
characteristics that do not permit a classic interpretation of microbial metabolic
parameter data. The resilience of soil microbial biomass and the role of soil organic
matter in sustaining microbial biomass under practically zero C inputs were assessed
in two long term incubation experiments using soils from the Broadbalk experiment
at Rothamsted (UK). Soils with low organic C contents, showed the greatest decline in
biomass C during the first 30 d of incubation. The ATP concentration of this rapidly
declining microbial biomass did not change during the prolonged incubation period,
confirming this peculiar character of the soil microbial biomass. Specific respiration
rate did not depend upon substrate availability, being higher in soils that had received
the lowest C inputs. Qualitative and quantitative changes observed in humic fractions
suggest that humified soil organic matter is a much more dynamic soil fraction than is
normally considered and provides a utilizable energy reserve for soil microorganisms.
Carbon levels can be successfully restored in soils through practices such as
incorporation of crop residues, re\u2010vegetation and application of manures, biosolids
and composts. Some amendments, such as olive mill waste compost, promote
incorporation of altered lignin structures, N\u2010containing compounds and
carbohydrates into humic acids. The mineral\u2010bound fraction of humic C also increases,
after their addition, and contributes to the accumulation of the most inert soil C pools
Photoreceptor damage induced by low-intensity light: model of retinal degeneration in mammals
Purpose: Retinal degeneration caused by a defect in the phototransduction cascade leads to the apoptosis of photoreceptor cells, although the precise molecular mechanism is still unknown. In addition, constant low light exposure produces photoreceptor cell death through the activation of downstream phototransduction. The authors investigated the time course and molecular mechanisms of death and the rhodopsin phosphorylation occurring during retinal degeneration after exposure to continuous low-intensity light.
Methods: Wistar rats were exposed to constant cool white 200 lx intensity LED light (LL) for one to ten days and compared with animals kept in the dark (DD) or controls exposed to a regular 12:12 h (LD) cycle. One eye from each rat was used for histological and quantitative outer nuclear layer (ONL) analysis and the other for biochemical assays.
Results: The histological analysis showed a significant reduction in the ONL of LL-exposed rats after seven days compared with LD- or DD-exposed rats. Retinal analysis by flow cytometer and the TUNEL assay revealed an increase in cell death in the ONL, the in vitro enzymatic activity assay and western blot analysis showing no caspase-3 activation. The rhodopsin analysis demonstrated more phosphorylation in serine 334 residues (Ser334) in LL-exposed than in LD- or DD-exposed rats. However, for all times studied, rhodopsin was completely dephosphorylated after four days of DD treatment.
Conclusions: Constant light exposure for seven days produces ONL reduction by photoreceptor cell death through a capase-3-independent mechanism. Increases in rhodopsin-phospho-Ser334 levels were observed, supporting the notion that changes in the regulation of the phototransduction cascade occur during retinal degeneration.Fil: Contin, Maria Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Arrieti, Milagros M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Benedetto, Maria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Bussi, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Guido, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; Argentin
Bioaccumulation of polycyclic aromatic hydrocarbons and survival of earthworms (Eisenia andrei) exposed to biochar amended soils
Biochar has a charcoal polycyclic aromatic structure which allows its long half-life in soil, making it an ideal tool for C sequestration and for adsorption of organic pollutants, but at the same time raises concerns about possible adverse impacts on soil biota. Two biochars were tested under laboratory-controlled conditions on Eisenia andrei earthworms: a biochar produced at low temperature from wine tree cuttings (WTB) and a commercial low tar hardwood lump charcoal (HLB). The avoidance test (48-h exposure) showed that earthworms avoid biochar-treated soil with rates higher than 16 t ha 121 for HLB and 64 t ha 121 for WTB. After 42 days, toxic effects on earthworms were observed even at application rates (100 t ha 121) that are generally considered beneficial for most crops. The concentration of HLB and WTB required to kill half of earthworms\u2019 population (LC50; 95 % confidence limits) in the synthetic OECD soil was 338 and 580 t ha 121, respectively. Accumulation of polycyclic aromatic hydrocarbons (PAH) in earthworms exposed to the two biochar types at 100 t ha 121 was tested in two soils of different texture. In biochar-treated soils, the average earthworm survival rates were about 64 % in the sandy and 78 % clay-loam soils. PAH accumulation was larger in the sandy soil and largest in soils amended with HLB. PAH with less than four rings were preferentially scavenged from the soil by biochars, and this behaviour may mask that of the more dangerous components (i.e. four to five rings), which are preferentially accumulated. Earthworms can accumulate PAH as a consequence of exposure to biochar-treated soils and transfer them along the food chain. Soil type and biochar quality are both relevant in determining PAH transfer
On the electromagnetic energy resolution of Cherenkov-fiber calorimeters
Electromagnetic calorimeters which sample the Cherenkov radiation of shower particles in optical fibers operate in a markedly different manner from calorimeters which rely on the dE/dx of shower particles. The well-understood physics of electromagnetic shower development is applied to the case of Cherenkov-fiber calorimetry (also known as quartz fiber calorimetry) and the results of systematically performed studies are considered in detail to derive an understanding of the critical parameters involved in energy measurement using such calorimeters. A quantitative parameterization of Cherenkov-fiber calorimetry electromagnetic energy resolution is proposed and compared with existing experimental results
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