4,020 research outputs found
Spin observables for pion photoproduction on the deuteron in the (1232)-resonance region
Spin observables for the three charge states of the pion for the pion
photoproduction reaction on the deuteron, , with polarized
photon beam and/or oriented deuteron target are predicted. For the beam-target
double-spin asymmetries, it is found that only the longitudinal asymmetries
and do not vanish, whereas all the circular
and the other longitudinal asymmetries do vanish. The sensitivity of spin
observables to the model deuteron wave function is investigated. It has been
found that only and are sensitive to the model deuteron wave
function, in particular in the case of -production above the
-region, and that other asymmetries are not.Comment: 16 pages, 8 figures, accepted for publication in J. Phys. G: Nucl.
Part. Phy
Polarization observables of the gamma d --> PiNN reaction in the Delta(1232)-resonance region
Polarization observables of the three charge states of the pion for the
reaction with polarized photon beam and/or oriented
deuteron target are evaluated over the whole (1232)-resonance region
adopting a nonrelativistic model based on time-ordered perturbation theory.
Results for the -meson spectra, linear photon asymmetry, vector and tensor
target asymmetries are presented. Particular attention is given, for the first
time, to double polarization asymmetries for which we present results for
and . We found that all other double
polarization asymmetries of photon and deuteron target are vanished.Comment: 17 Pages, 8 Figures, accepted for publication in Int. J. Mod. Phys.
Palm Ash as a Pozzolanic Material for Portland Cement Pastes
The effect of the substitution of palm ash (PA) on the physico-chemical and mechanical properties of Portland cement pastes (OPC) was clearly evaluated. Results showed that as the PA content increased, the fineness as well as the heat of hydration of the whole mix increased too. The water of consistency (WC) and set times (ST) decreased with the increase of PA content due to the presence of the water reducing admixture. The bound water content (BWn), bulk density (BD) and compressive strength (CS) improved and enhanced up to 20 % PA content, and then decreased onward at all hydration periods, while the total porosity decreased and then increased. Above 20 % PA content, all properties were adversely affected. The free lime content (FLn) of the OPC increased continuously up to 90 days, but decreased with PA content. The FTIR spectra illustrated that there is a large amount of free lime content with P0 (OPC), but it gradually decreased with PA content. The SEM microscopy demonstrated the formation of ettringite phase and aggregates of CSH in addition to free lime. In the case of PA blended cement pastes the ettringite was disappeared completely and well-defined crystals were detecte
Bayesian identification of LPV-BJ models : a multidimensional kernel approach
poster, no abstract available
Novel microwell-based spectrophotometric assay for determination of atorvastatin calcium in its pharmaceutical formulations
The formation of a colored charge-transfer (CT) complex between atorvastatin calcium (ATR-Ca) as a n-electron donor and 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a π-electron acceptor was investigated, for the first time. The spectral characteristics of the CT complex have been described, and the reaction mechanism has been proved by computational molecular modeling. The reaction was employed in the development of a novel microwell-based spectrophotometric assay for determination of ATR-Ca in its pharmaceutical formulations. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient (0.9995) was found between the absorbance and the concentration of ATR-Ca in the range of 10-150 μg/well. The limits of detection and quantitation were 5.3 and 15.8 μg/well, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from the drugs that are co-formulated with ATR-Ca in its combined formulations. The assay was successfully applied to the analysis of ATR-Ca in its pharmaceutical dosage forms with good accuracy and precision. The assay described herein has great practical value in the routine analysis of ATR-Ca in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for ATR-Ca, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed
Polymorphism of growth hormone gene and its association with wool traits in Egyptian sheep breeds
Growth hormone (GH) gene has been described as a candidate gene for marker-assisted selection in different farm animals. The present study was designed to identify the polymorphism in GH gene and its association with variation of wool traits in Egyptian sheep breeds. Wool and blood samples were collected from 42 animals including two breeds (Barki and Rahmani) and one crossbred (Rahmani x Awase). Measurements of wool traits were analyzed and involved staple strength (Str), staple length (STL), fiber diameter (FD) and clean fleece yield (CFW). DNA was extracted from blood samples and a 365-bp fragment from exon V was amplified by polymerase chain reaction (PCR). Single strand conformation polymorphisim (SSCP) analysis showed two conformational patterns. The pattern I was recorded to be more frequent (83.3, 92.86 and 90%) than pattern II (16.7, 7.14 and 10%) in Barki, Rahmani and crossbred, respectively. The sequence analysis showed one single nucleotide polymorphism (C/T). The pattern I (allele T) has been found to affect CFW and FD than pattern II (allele C). Whereas, C allele was more pronounced for Str and STL. These traits are the most important parameters determining commercial values of wool that are preferred for clothing or carpets industry. The nucleotide sequences of C and T alleles were submitted to GenBank and have the accession numbers: KT250511 and KT250512, respectively. In conclusion, the present results provide evidence that there is a single nucleotide polymorphism within GH gene in Egyptian sheep breeds. This mutation was found to have some effects on wool traits. Therefore our data show interesting prospects in future selection programs for improving wool industry.Key words: Sheep, wool, growth hormone (GH) gene, polymorphism, single strand conformation polymorphism (SSCP)
Phenotyping tomato root developmental plasticity in response to salinity in soil rhizotrons
Plants have developed multiple strategies to respond to salt stress. In order to identify new traits related to salt tolerance, with potential breeding application, the research focus has recently been shifted to include root system architecture (RSA) and root plasticity. Using a simple but effective root phenotyping system containing soil (rhizotrons), RSA of several tomato cultivars and their response to salinity was investigated. We observed a high level of root plasticity of tomato seedlings under salt stress. The general root architecture was substantially modified in response to salt, especially with respect to position of the lateral roots in the soil. At the soil surface, where salt accumulates, lateral root emergence was most strongly inhibited. Within the set of tomato cultivars, H1015 was the most tolerant to salinity in both developmental stages studied. A significant correlation between several root traits and aboveground growth parameters was observed, highlighting a possible role for regulation of both ion content and root architecture in salt stress resilience
Surface Roughness of Bulk Fill Composite after Simulated Toothbrushing with Different Dentifrices
AIM: The aim of the current in vitro study was to evaluate the changes in surface roughness of bulk fill composites after simulated toothbrushing with different dentifrices.
MATERIALS AND METHODS: Three types of bulk fill resin composites were used in this study; 27 specimens of each composite resin were randomly divided into three main groups (n = 9). Each main group was further subdivided into three subgroups (n = 3). Each group was subjected to simulated toothbrushing with three different dentifrices. One-way analysis of variance was used to evaluate the effect of brushing using dentifrices on the surface roughness of each type of composite resin, followed by Tukey’s test at a significance level of p ≤ 0.5%.
RESULTS: Results revealed that different effects on composite surface roughness were detected after simulating toothbrushing with different dentifrices. Lacalut toothpaste abrades more with Filtek Bulk Fill, Tetric N-Ceram then Bulk Fill SDR. Crest 3D toothpaste abrades more with Tetric N-Ceram, Bulk Fill SDR then Filtek Bulk Fill. BlanX toothpaste abrades more with Tetric N-Ceram, Bulk Fill SDR then Filtek Bulk Fill.
CONCLUSION: Chemical composition of both resin composites and dentifrices plays an important role in influencing the degree of surface roughness of bulk fill composite resin restorations
Silicon - single molecule - silicon circuits
In 2020, silicon - molecule - silicon junctions were fabricated and shown to be on average one third as conductive as traditional junctions made using gold electrodes, but in some instances to be even more conductive, and significantly 3 times more extendable and 5 times more mechanically stable. Herein, calculations are performed of single-molecule junction structure and conductivity pertaining to blinking and scanning-tunnelling-microscopy (STM) break junction (STMBJ) experiments performed using chemisorbed 1,6-hexanedithiol linkers. Some strikingly different characteristics are found compared to analogous junctions formed using the metals which, to date, have dominated the field of molecular electronics. In the STMBJ experiment, following retraction of the STM tip after collision with the substrate, unterminated silicon surface dangling bonds are predicted to remain after reaction of the fresh tips with the dithiol solute. These dangling bonds occupy the silicon band gap and are predicted to facilitate extraordinary single-molecule conductivity. Enhanced junction extendibility is attributed to junction flexibility and the translation of adsorbed molecules between silicon dangling bonds. The calculations investigate a range of junction atomic-structural models using density-functional-theory (DFT) calculations of structure, often explored at 300 K using molecular dynamics (MD) simulations. These are aided by DFT calculations of barriers for passivation reactions of the dangling bonds. Thermally averaged conductivities are then evaluated using non-equilibrium Green's function (NEGF) methods. Countless applications through electronics, nanotechnology, photonics, and sensing are envisaged for this technology
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