Browsing by Author "B. Singh"

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2-Acetylpyridine-2-aminobenzophenone-2-furoylhydrazone Complexes with 3d/-Metal Ions : A Magnetic and Spectral Study
(Indian Chemical Society, 1996) B. Singh; A.K. Srivastav
[No abstract available]
4-(2-thiazolyl)-1-(2-hydroxybenzaldehyde)thiosemica1badone as a chelating ligand : Complexes with oxovanadium(IV) cobalt(II) nickel(II), copper(II), cadmium(II) and mercury(II)
(1989) B. Singh; Urmila Srivastava
Complexes of the compositions VO(H2thbtsc)S04 Co(H2thbtsc)Cl2 M(H2thbtsc)2Ci2[M = Ni(II), Cu(II), Cd(II) and Hg(II)] and M(thbtsc).nH20 [M = VO(XV), Co(II), n=0; Ni(ll) and Cu(II), n = 2; H2thbtse = 4-(2-thiazolyl )-l-( 2-hydro xybenzaldehyde )thio seraicarb a zone] have been prepared and characterised by analytical data, electrical conductance, magnetic and spectroscopic studies. The bonding and stereochemistry of the complexes and chelating mode of the ligand are discussed. © 1989, Taylor & Francis Group, LLC. All rights reserved.
A new triterpene glycoside from Terminalia arjuna
(1995) B. Singh; V.P. Singh; V.B. Pandey; G. Rucker
A new triterpene diglucoside terminolitin (23-deoxyarjunolitin) has been isolated from the fruits of Terminalia arjuna (Combretaceae) and was identified by IR, 1H- and 13C-NMR spectroscopy.
Actions of some flavonoids on specific and non-specific immune mechanisms
(Urban und Fischer Verlag Jena, 1996) M.L. Sharma; B. Singh; B.K. Chandan; A. Khajuria; A. Kaul; S. Bani; S.K. Banerjee; S.S. Gambhir
The immunomodulatory activity of some flavonoids on antigen specific humoral and cell mediated immune responses and complement-mediated hemolysis has been investigated and compared with that of levamisole. Flavanone, 6-methoxyflavanone, 7-methoxyflavanone and bavachinin enhanced the sheep erythrocyte (SRBC), induced primary and secondary humoral immune responses in mice, and 6-hydroxyflavanone, 7-hydroxyflavanone and rutin inhibited primary response. Levamisole slighty stimulated the primary and suppressed the secondary response. All the flavonoids tested decreased the manifestation of SRBC induced delayed type hypersensitivity reaction and showed no effect on classical or alternative pathway dependent hemolysis. The studies revealed the significant immunomodulatory potential of these flavonoids, methoxy derivatives having immunostimulatory activity and hydroxy derivatives immunosuppressive properties.
Agro-techniques for baby corn production
(Springer Singapore, 2019) M.K. Singh; S.P. Singh; B. Singh
Baby corn (Zea mays L.) is a high-value crop, gaining popularity fast, and relatively recently introduced in India. Baby corn may be raised year-round, has short duration, and is fast growing and thus opens avenues for crop diversification. Baby corn is a suitable crop for cultivation under diverse agroclimatic conditions. The agro-techniques for baby corn are different from maize, viz., varieties, seed rate, plant density, detasseling, fertilizer management, and harvesting schedule. Higher plant densities with optimum geometry are essential to harness the yield potential. Intercropping with short-duration legumes and vegetables during winters gave profitable response. Removal of tassel with its emergence considerably enhances the yield of baby corn. Combined approach (soil application followed by foliar) in nitrogen management improves yield and quality of winter baby corn. Adoption of staggered planting will be helpful for continued supply for a longer period and in reducing the labor requirement during peak period. Standardization of the improved agro-techniques for diverse farming situations is required for wider popularization of the baby corn cultivation in India. © Springer Nature Singapore Pte Ltd. 2019.
An acylflavone glucoside of Echinops echinatus flowers
(1996) S.N. Ram; R. Roy; B. Singh; R.P. Singh; B. Pandey v.
[No abstract available]
An aroylhydrazone as chelating agent : 4f metal complexes of 2, 6-diacetylpyridine bis(2-furoylhydrazone)
(Marcel Dekker Inc., 1996) B. Singh; Pramod K. Singh; Praveen K. Singh
Two types of complexes, [Ln2Cl4(H2dapf) (H2O)6]Cl2, and [Ln(Hdapf)(OH)2]2 [Ln = La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III) and Dy(III); H2dapf = 2,6-diacetylpyridine bis(2-furoylhydrazone)], having coordinated neutral (H2dapf) or uninegative (Hdapf) hydrazones, respectively, have been isolated from the reaction of the lanthanide chloride and the hydrazone in neutral and slightly alkaline solutions, respectively. The complexes were characterized by elemental analyses, molar conductance, TGA and DTA, magnetic susceptibility, electronic, infrared and NMR (1H and 13C) spectral data. The nephel auxetic ratio (β), covalency (δ) and bonding (b1/2) parameters have been evaluated for the Nd(III) complexes.
An experimental setup for studying the core-excited atoms and molecules by electron impact using energy analysed electron–ion coincidence technique
(Scientific Publishers, 2017) S. Kumar; S. Prajapati; B. Singh; B.K. Singh; R. Shanker
Operation and performance of an apparatus for studying the decay dynamics relevant to core–hole decay processes in atoms and molecules excited by energetic electrons using an energy analysed electron–ion coincidence technique are described in some detail. The setup consists of a time- and position sensitive double-field linear TOF mass spectrometer coupled with a dual MCP detector and a single-pass CMA to select the energy of detected electrons. Details of different components involved in the setup are presented and discussed. To demonstrate the performance and capability of the apparatus, we present some typical results extracted from the TOF argon ion-mass spectra observed in coincidence with 18-energy selected electrons emitted from interaction of a continuous beam of 3.5 keV electrons with a dilute gaseous target of argon atoms. Specifically, the variation of relative correlation probability for the final ion-charge states Ar1+ to Ar4+ produced in the considered collision reactions as a function of energy of emitted electrons is determined and discussed. © 2017, Indian Association for the Cultivation of Science.
An N-formyl cyclopeptide alkaloid from Zizyphus nummularia bark
(1995) B. Singh; V.B. Pandey
A 13-membered N-formylcyclopeptide alkaloid, nummularine-T, has been isolated from the bark of Zizyphus nummularia and its structure established by spectroscopic and chemical methods. It provides the fourth example of a naturally occurring N-formyl cyclopeptide alkaloid. © 1995.
Anchoring transition driven by short range ordering in calamitic-discotic composites
(Elsevier, 2015) Srividhya Parthasarathi; D.S. Shankar Rao; Hemant Kumar Singh; B. Singh; S. Krishna Prasad
We report investigations at atmospheric as well as elevated pressures on a host calamitic nematic liquid crystal doped with a discotic material exhibiting a novel anchoring transition (ANT), not present in the pure host. The change over from the substrate-surface determined planar to the homeotropic orientation occurs at a specific temperature that is governed by, as seen from X-ray and Frank bend and splay constants data, the short-range ordering changing from that for a columnar nematic to that of a standard nematic. Applied pressure diminishes the tendency for the orientation change thereby enhancing the range of the planar alignment finally annulling ANT. We ascribe the observed features to the competition between the anchoring energy of the aligning surface and the tendency of the structure to be parallel to the surface creating frustration and leading to ANT. Phase diagrams involving ANT have been constructed at atmospheric as well as elevated pressures. © 2015 Elsevier B.V. All rights reserved.
Angular dependence of Kβ/Kα intensity ratios of thick Ti and Cu pure elements from 10–25 keV electron bombardment
(Scientific Publishers, 2018) B. Singh; S. Kumar; S. Prajapati; B.K. Singh; X. Llovet; R. Shanker
Measurements yielding the first results on angular dependence of Kβ/Kα X-ray intensity ratios of thick Ti (Z = 22) and Cu (Z = 29) targets induced by 10–25 keV electrons are presented. The measurements were done by rotating the target surface around the electron beam direction in the angular detection range 105° ≤ θ ≤ 165° in the reflection mode using an energy dispersive Si PIN photodiode detector. The measured angular dependence of Kβ/Kα intensity ratios is shown to be almost isotropic for Ti and Cu targets for the range of detection angles, 105° ≤ θ ≤ 150°, while there is a very weak increase beyond 150° for both targets. No dependence of Kβ/Kα intensity ratios on impact energy is observed; while on average, the value of the Kβ/Kα X-ray intensity ratio for Cu is larger by about 8% than that for Ti, which indicates a weak Z-dependence of the target. The experimental results are compared with those obtained from PENELOPE MC calculations and from the Evaluated Atomic Data Library (EADL) ratios. These results on Kβ/Kα X-ray intensity ratios are found to be in reasonable agreement in the detection angle range 105° ≤ θ ≤ 150° to within uncertainties, whereas the simulation and experimental results show a very slight increase in the intensity ratio with θ as the latter attains higher values. The results presented in this work provide a direct check on the accuracy of PENELOPE at oblique incidence angles for which there has been a lack of measurements in the literature until now. © 2018, Indian Association for the Cultivation of Science.
Antioxidant phytochemicals in cabbage (Brassica oleracea L. var. capitata)
(2006) Jagdish Singh; A.K. Upadhyay; A. Bahadur; B. Singh; K.P. Singh; Mathura Rai
Eighteen different cabbage cultivars were assayed for variability between the cultivars for the antioxidant phytonutrients. The Vitamin C content ranged from 5.66 to 23.50 mg/100 g fresh weight. The maximum Vitamin C content was recorded in cultivar Sprint Ball (23.50 mg/100 g), followed by cv. Gungaless (12.86 mg/100 g). The β-carotene content in cabbage ranged from 0.009 to 0.124 mg/100 g fresh weight. The maximum β-carotene content was recorded in cv. Quisto (0.124 mg/100 g), followed by Green Challenger (0.115 mg/100 g) and Rare Ball (0.114 mg/100 g). The minimum values for β-carotene was noted in cv. Pusa Mukta (0.009 mg/100 g). Lutein content was also recorded in the cabbage cultivars, which ranged from 0.021 to 0.258 mg/100 g fresh weight. Maximum lutein content was recorded in Quisto (0.258 mg/100 g) and minimum in Pusa Mukta (0.021 mg/100 g). Vitamin E (dl-α-tocopherol) was estimated only in 14 cabbage cultivars, which ranged from 0.030 to 0.509 mg/100 g fresh weight. Maximum α-tocopherol content was recorded in Rare Ball (0.509 mg/100 g) and minimum in Green Cornell (0.030 mg/100 g). Total phenol content was also estimated only in 14 cultivars and the values ranged from 12.58 to 34.41 mg/100 g fresh weight. Amongst the three different cultivated forms of cabbage, red cabbage had higher Vitamin C (24.38 mg/100 g), dl-α-tocopherol (0.261 mg/100 g) and phenolic content (101.30 mg/100 g) as compared to the white cabbage and savoy cabbage. © 2006 Elsevier B.V. All rights reserved.
Changes in antioxidant enzyme activities and gene expression in two muskmelon genotypes under progressive water stress
(Springer Netherlands, 2017) W.A. Ansari; N. Atri; B. Singh; S. Pandey
Responses of two muskmelon (Cucumis melo L.) genotypes (drought tolerant SC-15 and drought susceptible EC-564755) were analyzed at 0, 7, 14, and 21 d of progressive water stress. Although water deficit caused a significant decline in relative water content, the magnitude of reduction was lower in SC-15. Electrolyte leakage, hydrogen peroxide, and malonydialdehyde generation were higher in EC-564755, whereas accumulation of proline was higher in SC-15. Higher activities of antioxidant enzymes, such as catalase, superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase, and higher expression of the respective genes were recorded in SC-15 than in EC-564755. Expressions of DREB2C and DREB3 in SC-15 revealed a fluctuating pattern with down-regulation on days 7 and 21 of water stress, whereas up-regulation was observed on day 14. Concurrently, both genes in EC-564755 showed continuous down-regulation on days 7, 14, and 21 of water stress. Expressions of RD22 and dehydrin recorded on days 7, 14, and 21 were lower in SC-15. The cluster analysis showed that, these two genotypes had a clear distinction in physiological and biochemical properties and gene expressions under water stress and the genotype SC-15 had more efficient osmoprotectant mechanism than genotype EC-564755 under water deficit conditions. © 2017, The Institute of Experimental Botany.
Chelation of 2-aminobenzophënone- 2-furoylhydrazone with some bivalent metal ions: Magnetic and spectral studies
(1994) B. Singh; A.K. Srivastav; P. Sahai
Reaction of 2-aminobenzophenone-2-furoylhydrazone (Habfh) with metal salts yields complexes of the chemical compositions V0(Habfh)2S04, M(Habfh)2Cl2 and M(abfh)2 [M =OV(IV), Mn(II), Co(ll), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The complexes are non-electrolytes in acetonitrile and dimethylformamide solution. The electronic structures of the complexes have been studied by magnetic susceptibility, electronic, photoecoustic and esr spectral studies. Infrared and n.m.r. spectra have been used to ascertain the ligational properties of Habfh. An X-ray diffraction study has been used to elucidate the shape and size of the unit lattice of copper(II) and zinc(II). © 1994, Taylor & Francis Group, LLC. All rights reserved.
Comparative evaluation of Bis(thiosemicarbazone)- Biotin and Met-ac-TE3A for tumor imaging
(Elsevier, 2016) Sweta Singh; Anjani K. Tiwari; Raunak Varshney; R. Mathur; Gauri Shukla; N. Bag; B. Singh; Anil K. Mishra
2,2′,2″-(11-(2-((4-mercapto-1-methoxy-1-oxobutan-2-yl)amino)-2-oxoethyl)-1,4,8,11-tetraaza cyclotetradecane-1,4,8-triyl)triacetic acid, Met-ac-TE3A and (E)-N-methyl-2-((E)-3-(2-(2-(5-((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoyl)hydrazinecarbono-thioyl)hydrazonobutan-2-ylidene)hydrazinecarbothioamide, Bis(thiosemicarbazone)- Biotin were synthesized and evaluated for imaging application. The pharmacokinetics of these ligands were determined by tracer methods. In vitro human serum stability of 99mTc Met-ac-TE3A/99mTc Bis(thiosemicarbazone)-Biotin after 24 h was found to be 96.5% and 97.0% respectively. Blood kinetics of both ligands in normal rabbits showed biphasic clearance pattern. Ex vivo biodistribution study revealed significant initial tumor uptake and high tumor/muscles ratio which is a pre-requisite condition for a ligand to work as SPECT-radiopharmaceutical for tumor imaging. © 2015 Elsevier B.V.
Comparison of BTSE-RGD with DOTA-RGD as a potential imaging agent for tumors
(Royal Society of Chemistry, 2015) Raunak Varshney; Sweta Singh; Anjani K. Tiwari; Rashi Mathur; Shivani Singh; Puja Panwar; Neelam Yadav; Krishna Chutani; B. Singh; Anil K. Mishra
RGD and its analogues are very important compounds and can be used as potential tumor-targeting agents. Bisthiosemicarbazone-conjugated RGD (BTSE-RGD) and DOTA-RGD were prepared using a chemical strategy based on peptide synthesis and chemoselective ligations. BTSE-RGD comprises two domains, the first a tumour selective domain and the other a chelating vehicle, for conjugation of radioisotopes. Both compounds were synthesized and labelled with 99mTc and radiochemically analysed by HPLC. The stability of the radioconjugate in the presence of human serum was checked at 37°C up to 8 h. Labelling yield of 96.8 ± 0.32% was obtained, which corresponds to a specific activity in the range of 36-89 MBq μmol-1 for BTSE-RGD. The BTSE-RGD conjugate was examined in vitro for its ability to bind with the αvβ3 receptor. The functionalized BTSE-RGD displayed a binding affinity toward αvβ3 integrin (31.9 ± 6.8 nM) many-fold better than DOTA-RGD. 99mTc-BTSE-RGD showed a slower distribution half-life (T1/2α) and elimination half-life (T1/2β) of 65 ± 0.001 min and 21 h 15 min ± 0.001 min, respectively, in comparison to 99mTc-DOTA-RGD, with T1/2α of 18 ± 0.001 min and T1/2β of 9 h 10 min ± 0.005 min. Biodistribution study showed better tumor-to-muscle ratio for BTSE-RGD, which reaches maximum around 3.5 (% ID) in 2 h, while for DOTA-RGD the maximum was 13.60 at 24 h. © The Royal Society of Chemistry.
Complexes of Some New Diacylhydrazines: Synthesis, Magnetic and Spectral Studies
(1995) B. Singh; Preeti Sahai
The new N, 0 donor ligands N-acetyl-N-furoyl (H2afh) and N-acetyl-N-thenoylhydrazines (H2ath) have been synthesized and characterized by melting point, analytical data and IR spectral studies. The complexes of the types M(L)2Cl2[M = Mn(II), Ni(ll), Zn(II); L = H2afh; M = Mn(II), Ni(ll), Cu(ll) and Zn(II), L = H2ath, M(L-H)C1(H20)2, [M = Co(ll) and Cu(II), L = H2afh; M = Co (11), L = H2ath] and M(L-2H).(H20)2[M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); L = H2afh and H2ath] have been synthesized and authenticated by analytical data, molar conductance, magnetic susceptibility and spectroscopic methods. © 1995, Taylor & Francis Group, LLC. All Rights Reserved.
Crystal and molecular structure of Dichloro‐di‐(2‐Furoylhydrazine) Zinc(II)
(1984) R.N. Singh; B. Singh; M. Singh
[No abstract available]
Crystal and molecular structure of Dichloro‐mono‐aquo(2‐furoylacetone hydrazone) Copper (II)
(1984) B. Singh; R.N. Singh
[No abstract available]
Design and performance simulation of a segmented-absorber based muon detection system for high energy heavy ion collision experiments
(Elsevier, 2015) S. Ahmad; P.P. Bhaduri; H. Jahan; A. Senger; R. Adak; S. Samanta; A. Prakash; K. Dey; A. Lebedev; E. Kryshen; S. Chattopadhyay; P. Senger; B. Bhattacharjee; S.K. Ghosh; S. Raha; M. Irfan; N. Ahmad; M. Farooq; B. Singh
A muon detection system (MUCH) based on a novel concept using a segmented and instrumented absorber has been designed for high-energy heavy-ion collision experiments. The system consists of 6 hadron absorber blocks and 6 tracking detector triplets. Behind each absorber block a detector triplet is located which measures the tracks of charged particles traversing the absorber. The performance of such a system has been simulated for the CBM experiment at FAIR (Germany) that is scheduled to start taking data in heavy ion collisions in the beam energy range of 6-45 A GeV from 2019. The muon detection system is mounted downstream to a Silicon Tracking System (STS) that is located in a large aperture dipole magnet which provides momentum information of the charged particle tracks. The reconstructed tracks from the STS are to be matched to the hits measured by the muon detector triplets behind the absorber segments. This method allows the identification of muon tracks over a broad range of momenta including tracks of soft muons which do not pass through all the absorber layers. Pairs of oppositely charged muons identified by MUCH could therefore be combined to measure the invariant masses in a wide range starting from low mass vector mesons (LMVM) up to charmonia. The properties of the absorber (material, thickness, position) and of the tracking chambers (granularity, geometry) have been varied in simulations of heavy-ion collision events generated with the UrQMD generator and propagated through the setup using the GEANT3, the particle transport code. The tracks are reconstructed by a Cellular Automaton algorithm followed by a Kalman Filter. The simulations demonstrate that low mass vector mesons and charmonia can be clearly identified in central Au+Au collisions at beam energies provided by the international Facility for Antiproton and Ion Research (FAIR). © 2014 Elsevier B.V. All rights reserved.