Browsing by Author "M.K. Pandey"
Now showing 1 - 7 of 7
- Results Per Page
- Sort Options
PublicationArticle Biochemical and morphological variability in Sclerotium rolfsii(2005) U.P. Singh; M.K. Pandey; D.P. Singh[No abstract available]PublicationArticle Biochemical investigations of sclerotial exudates of Sclerotium rolfsii and their antifungal activity(2007) M.K. Pandey; B.K. Sarma; D.P. Singh; U.P. SinghExudates from sclerotia of two Sclerotium rolfsii isolates (one causing collar rot in Cicer arietinum, isolate VC971, and the other leaf spots in Rauvolfia serpentina, isolate VL016) were assayed for their antifungal activity against 26 fungi consisting of plant parasites as well as saprophytes. Spore germination of all the test fungi was affected by the exudates reaching 100% in some cases. Foliar spray with exudates of isolate VL016 significantly reduced disease incidence of balsam (Impatiens balsamina) powdery mildew caused by Erysiphe cichoracearum and pea (Pisum sativum) powdery mildew caused by Erysiphe pisi, under field conditions. Characterization of exudates from 25 isolates of S. rolfsii revealed pH ranging from 3.8 to 5.3 and colour from light yellow to deep yellow. Among the phenolic acids found in the exudates were tannic, gallic, caffeic, vanillic, ferulic, chlorogenic and cinnamic acids. Oxalic acid was also found in varied amounts. Among the phenolic acids, ferulic acid was found to be present at high concentration in exudates of most isolates (3.9-153.4 μg/ml). The antioxidant properties of phenolics, which generally inhibit fungal morphogenesis including spore germination along with the antifungal nature of some phenolics are chiefly attributed to the inhibitory effect of sclerotial exudates of S. rolfsii. Additionally, both the isolates VC971 and VL016 showed almost similar antifungal activities despite they are of different origin and thereby demonstrate the antifungal nature of sclerotial exudates. © 2007 The Authors.PublicationArticle Charge exchange collisions of H+/D+ ions with alkaline Earth atoms (Ca, Mg)(Springer New York, 2007) M.K. Pandey; R.K. Dubey; D.N. TripathiThe Classical Trajectory Monte Carlo (CTMC) Method has been used to calculate the differential, partial and total single electron capture cross sections for the collision of H+/D+ with Ca and Mg atoms in the energy range of 1-100 keV. The differential cross sections at angles near the diffraction limit (<0.1°) in both systems show a forward peak followed by an asymptotic fall at higher angles. Total and partial capture cross sections are found to be in good agreement with the experimental observations. Oscillations in the partial capture cross sections have been explained due to the swapping of the field electron. Isotope effect in the electron transfer is reported to be negligible. © 2006 EDP Sciences/Società Italiana di Fisica/Springer-Verlag.PublicationArticle Charge transfer in keV proton collision with atomic oxygen: Differential and total cross sections(Springer New York, 2007) M.K. Pandey; R.K. Dubey; D.N. TripathiClassical Trajectory Monte Carlo method (CTMC) with the modal interaction potential [1] has been used to simulate the differential, total and partial capture cross sections in proton-oxygen atom collisions in the energy range of 0.5-200 keV. An interesting feature of the calculated differential cross sections (DCS) curve below the scattering angle 0.1° is the presence of oscillations showing asymmetry in angular positions. The oscillations in the partial cross sections are explained in terms of swapping effect. The DCS and total cross sections are found to be in good agreement with the experimental as well as other theoretical results. © 2007 EDP Sciences/Società Italiana di Fisica/Springer-Verlag.PublicationArticle Constraints on millicharged particles with low-threshold germanium detectors at Kuo-Sheng Reactor Neutrino Laboratory(American Physical Society, 2019) L. Singh; J.W. Chen; H.C. Chi; C.-P. Liu; M.K. Pandey; H.T. Wong; C.P. Wu; M. Agartioglu; M. Deniz; H.B. Li; S.T. Lin; V. Sharma; M.K. Singh; V. Singh; Q. YueRelativistic millicharged particles (χq) have been proposed in various extensions to the standard model of particle physics. We consider the scenarios where they are produced at nuclear reactor core and via interactions of cosmic rays with the Earth's atmosphere. Millicharged particles could also be candidates for dark matter and become relativistic through acceleration by supernova explosion shock waves. The atomic ionization cross section of χq with matter are derived with the equivalent photon approximation. Smoking-gun signatures with significant enhancement in the differential cross section are identified. New limits on the mass and charge of χq are derived, using data taken with a point-contact germanium detector with 500 g mass functioning at an energy threshold of 300 eV at the Kuo-Sheng Reactor Neutrino Laboratory. .PublicationArticle On quantum scattering by δ′(x) and quasi ′(x) distributions(2007) Ritesh Kumar Dubey; V.J. Menon; M.K. Pandey; D.N. TripathiThe zero-range interaction U(x) occurring in the one-dimensional, time-independent Schrödinger equation is regarded as a smoothed distribution characterized by a tiny length scale b such that the origin becomes an ordinary point. A neighbourhood around the origin is scanned by defining inner demarcation points a± = ±b/N and outer demarcation points b± ≡ ±Nb with N ≫ 1. Then a sequence of simple Lemmas permits (i) construction of a systematic procedure for simultaneously solving the scattering wave function ψ(0) at the origin, its derivative ψ(0) there, the transmission amplitude B, as well as the reflection amplitude D; and (ii) unambiguous application to scattering by the previously known δ′(x) and newly proposed quasi δ′(x) potentials in the Cauchy representation of various distributions. © 2007 NRC Canada.PublicationNote Viral spillover to humans: could Langya (LayV) virus cause a pandemic?(Oxford University Press, 2023) S.K. Patel; K. Sharma; A. Agrawal; K.C. Nikhil; A.K. Niranjan; M.K. Pandey; N. Arya; M. Murali; J. Rana; S.P. Tiwari[No abstract available]