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  • Author: P. Mukhopadhyay, x
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Abstract

In this paper the question of the asymptotic conformal invariance of the off-shell amplitude for the process π0 → 2 γ has been investigated. It has been shown that the off-shell amplitude for the process concerned can be given an asymptotically conformal covariant form by using a parton model description of the neutral pion instead of treating the pion as an elementary particle. This investigation shows that the conclusion regarding the question of the asymptotic conformal invariance of the off-shell amplitude for the process π0 → 2 γ obtained from the parton model along with the use of conformal covariant operator product expansions is the same as that of the Johnson-Baker-Willey version of finite QED from which the asymptotic conformal invariance of the 3-point Green's function for the process π0 → 2 γ follows as a necessary consequence.

Abstract

In the present chapter, fuzzy approach is utilized in the assessment of frequency response function (FRF) analysis of functionally graded plates (FGPs). FGP has significant applications in aerospace, marine, medical, and civil structures due to its unique properties such as high-temperature resistance, non-corrosiveness, and high strength and stiffness. The uncertainty quantification of FRF is portrayed. The fuzziness is considered due to its variability in material properties corresponding to the various α-cuts. The power law is implied for characterizing the material modelling. A parametric study is carried out to observe the effect of location of drive point and cross points on uncertain bounds of FRF with respect to crisp values.

Abstract

The prediction skill of tropical synoptic scale transients (SSTR) such as monsoon low and depression during the boreal summer of 2007–2009 are assessed using high resolution ECMWF and NCEP TIGGE forecasts data. By analyzing 246 forecasts for lead times up to 10 days, it is found that the models have good skills in forecasting the planetary scale means but the skills of SSTR remain poor, with the latter showing no skill beyond 2 days for the global tropics and Indian region. Consistent forecast skills among precipitation, velocity potential, and vorticity provide evidence that convection is the primary process responsible for precipitation. The poor skills of SSTR can be attributed to the larger random error in the models as they fail to predict the locations and timings of SSTR. Strong correlation between the random error and synoptic precipitation suggests that the former starts to develop from regions of convection. As the NCEP model has larger biases of synoptic scale precipitation, it has a tendency to generate more random error that ultimately reduces the prediction skill of synoptic systems in that model. The larger biases in NCEP may be attributed to the model moist physics and/or coarser horizontal resolution compared to ECMWF.

Abstract

The crystal structure of the title compound, prepared from p-(2-dimethylaminoethyl)phenol (hordenine) and o-phosphoric acid, was determined from single-crystal X-ray diffractometer data. The crystals were monoclinic, space group P21/n, the lattice constants a = 18.530(2), b = 8.077(2), c = 23.881(2) Å, β = 95.21(1)°, Z = 4, Dc = 1.323, Dm = 1.33 Mg · m−3, F(000) = 1520, μ(Mo) = 0.192 mm−1. The structure was solved by direct methods and refined by least-squares calculations to a final R = 0.045 for 3659 uniquely observed reflections with I ⩾ 2σ(I). All the three independent hordenine molecules in the asymmetric unit of the phosphate complex exhibited trans conformation with maximally extended ethylamine side chains almost perpendicular to the phenyl rings. The geometry of the oxyanionic HPO4 −2 and H2PO4 groups are slightly distorted tetrahedra, with their P-atoms at the centre of the tetrahedron and the four oxygen atoms situated at the corners. The crystal structure is stabilized by a three-dimensional intricate network of hydrogen bonds with p-hydroxyl and tertiary-amino groups of the hordenine cations strongly bonded to oxygen atoms of the HPO4 −2 and H2PO4 anions. These results are likely to provide some informations about the phosphate-binding properties of adrenergic phenylethylamines.

Abstract

Monomer dynamics in sodium dodecyl sulfate (SDS) micellar solution at room temperature as studied by quasi elastic neutron scattering (QENS) technique is reported. The elastic incoherent structure factor (EISF) obtained from the analysis of QENS data suggests that the SDS chains perform uniaxial rotational diffusion along the long molecular axis. The rotation diffusion coefficient was found to decrease with the increase in the concentration of the surfactants. It is observed that on addition of electrolyte (0.8 M NaCl) the motion is arrested. Addition of salt is known to induce the growth in SDS micelles, here it is found to affect the dynamics of monomers also. This is due to the combined effect of closer packing of the monomers within the micelle and the tendency of amphiphilic molecules to stabilize due to the presence of electrolytes.

Abstract

Background: Arsenic, acting as an endocrine disruptor, causes reproductive malfunctions. Studies have been undertaken to find out whether the co-supplementation of α-tocopherol and ascorbic acid (AT-AA) could reduce the arsenic-induced testicular toxicity caused by oxidative stress and resulting DNA damage.

Methods: Adult male Wistar rats (120±10 g) were given arsenic trioxide [3 mg/kg body weight (b.wt.) per day] for 30 consecutive days and the supplement group received α-tocopherol (400 mg/kg b.wt. per day) and ascorbic acid (200 mg/kg b.wt. per day). Reproductive functions were evaluated with respect to the histoarchitecture, gametokinetic activity, androgenic potential, glutathione-dependent antioxidant status and DNA damage of the testis.

Results: Arsenic treatment caused marked reduction in the relative weight of the testis (p<0.05) but showed no effect on body weight. The number of germ cells at stage VII of the spermatogenic cycle (p<0.01), the seminiferous tubular diameter (p<0.001) and Leydig cell nuclear area (p<0.01) were significantly reduced. Notable decrease in the activities of testicular Δ5, 3β-HSD (p<0.05) and 17β-HSD (p<0.01) with a concomitant fall in serum testosterone level (p<0.01) along with significant diminution in testicular glutathione S-transferase (p<0.05) activity and reduced glutathione level (p<0.01) were observed. Significant DNA damage (p<0.001) in spermatogenic cells was also noted. All these alterations including DNA strand breakage were seen to be protected with the coadministration of AT-AA.

Conclusions: The data suggest that the protection of testicular toxicity in arsenic-exposed adult rats is possible with combined coadministration of AT-AA.