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101.
3β-Acetoxy-9,19-cyclo-4,4,14α-trimethyl-5α-pregnan-20-one, an intermediate readily accessible from cycloartenol/cyclolaudenol has been transformed into cyclobuxophyllinine-M, an alkaloid isolated from certain Buxus Spp. This compound has been earlier converted into the closely related alkaloids cyclobuxophilline-K and buxanine-M. The present work formally constitutes the synthesis of these alkaloids from cycloartenol. 相似文献
102.
103.
Chandra Mouli Pandey Srishti Dewan Seema Chawla Birendra Kumar Yadav Gajjala Sumana Bansi Dhar Malhotra 《Analytica chimica acta》2016
We report results of the studies relating to controlled deposition of the amino-functionalized silica-coated zinc oxide (Am-Si@ZnO) nano-assemblies onto an indium tin oxide (ITO) coated glass substrate using Langmuir-Blodgett (LB) technique. The monolayers have been deposited by transferring the spread solution of Am-Si@ZnO stearic acid prepared in chloroform at the air-water interface, at optimized pressure (16 mN/m), concentration (10 mg/ml) and temperature (23 °C). The high-resolution transmission electron microscopic studies of the Am-Si@ZnO nanocomposite reveal that the nanoparticles have a microscopic structure comprising of hexagonal assemblies of ZnO with typical dimensions of 30 nm. The surface morphology of the LB multilayer observed by scanning electron microscopy shows uniform surface of the Am-Si@ZnO film in the nanometer range (<80 nm). These electrodes have been utilized for chronic myelogenous leukemia (CML) detection by covalently immobilizing the amino-terminated oligonucleotide probe sequence via glutaraldehyde as a crosslinker. The response studies of these fabricated electrodes carried out using electrochemical impedance spectroscopy show that this Am-Si@ZnO LB film based nucleic acid sensor exhibits a linear response to complementary DNA (10−6–10−16 M) with a detection limit of 1 × 10−16 M. This fabricated platform is validated with clinical samples of CML positive patients and the results demonstrate its immense potential for clinical diagnosis. 相似文献
104.
We study the effect of momentum-dependent interactions and a broader Gaussian on multifragmentation. We also look into the details of the fragment structure for a broader Gaussian and momentum-dependent interactions. We find that nucleons forming the fragments belong to the same region of the phase space. 相似文献
105.
Anjali Malik Agnieszka Najda Aarti Bains Renata Nurzyska-Wierdak Prince Chawla 《Molecules (Basel, Switzerland)》2021,26(14)
Currently, the potential utilization of fruits and vegetable waste as a source of micronutrients and antioxidants has increased. The present study, therefore, aimed to determine the antimicrobial and anti-inflammatory activities of Citrus nobilis peel extract. A modified solvent evaporation technique was employed for peel extract preparation. For effective utilization of the natural product, quantitative analysis of phenolic compounds was carried out using liquid chromatography and mass spectroscopy technique. Phenolic and flavonoids were present in high amounts, while β-carotene and lycopene were present in vestigial amounts. The antimicrobial efficiency of peel extract was evaluated against four bacterial strains including Staphylococcus aureus (MTCC 3160), Klebsiella pneumoniae (MTCC 3384), Pseudomonas aeruginosa (MTCC 2295), and Salmonella typhimurium (MTCC 1254), and one fungal strain Candida albicans (MTCC 183), and zone of inhibition was comparable to the positive control streptomycin and amphotericin B, respectively. The extract of Citrus nobilis peels showed effective anti-inflammatory activity during human red blood cell membrane stabilization (HRBC) and albumin denaturation assay. The extracts also exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity ranging from 53.46 to 81.13%. Therefore, the obtained results suggest that Citrus nobilis peel could be used as an excellent source of polyphenols and transformed into value-added products. 相似文献
106.
Sonal Singhal Amit Kumar Chawla Sandeep Nagar Hari Om Gupta Ramesh Chandra 《Journal of nanoparticle research》2010,12(4):1415-1421
Thin films of Zn1−x
Cd
x
S (0.1 ≤ x ≤ 0.5) were prepared by using pulsed laser ablation technique on corning glass substrates. Phase transition from cubic to
hexagonal in Zn1−x
Cd
x
S films is determined by X-ray diffraction analysis. We observed a lowering in the phase transition temperature with increase
in the cadmium concentration. Transmission electron microscopy suggests the crystalline nature of thin films with average
particle size of 15 nm. The grown Zn1−x
Cd
x
S samples show the high peak intensity ratio of the near band edge emission to the defect center luminescence even at room
temperature, which indicates the small concentration of complex defects in the samples. Photoluminescence measurement show
stoichiometric dependence of the energy band gap and is found to have quadratic dependence on x. 相似文献
107.
S. S. Chawla P. K. Srivastva 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(5):793-814
Fluid motion induced by the torsional oscillations (of angular velocity bΩcosω T) of an infinite disk in contact with an incompressible viscous rotating (with angular velocity aΩ) fluid of semi-infinite extent is analysed when the amplitude parameter α( = b/a) varies from zero to infinity. Composite solutions valid over the whole of the flow regime and specific expressions for the
shearing stress components at the disk and for the axial flow in the far region are obtained for low and high frequencies
of torsional oscillations. Using the method of matched asymptotic expansions, we find that the region of the mean flow increases
with α and reaches a maximum before settling down to the Rosenblat profile. Series expressions (for α < 1) are deduced for
physical quantities of interest when the fluid in the far field and the disk are rotating with different angular velocities
(in the same or in the opposite sense), which agree well with the known numerical results.
(Received: April 7, 2003; revised: September 29, 2005) 相似文献
108.
Karun Gurjar Sakshi Rampuria Uma Joshi Paramita Palit K. V. Bhatt T. Mohapatra Ramavtar Sharma 《Applied biochemistry and biotechnology》2014,173(8):2116-2128
Moth bean (Vigna aconitifolia (Jacq.) Marechal), an important grain-legume crop grown in hot desert regions of Thar, under scorching sun rays, was investigated for heat tolerance at molecular level. In the present study, we constructed a forward suppression subtractive hybridization (SSH) cDNA library of heat tolerant genotype RMO-40 to identify genes expressing under delayed response to elevated temperature. Heat induction was carried out by exposing 14-day-old seedlings to elevated temperature of 42 °C for 30 min. A total of 125 unigenes (33 contigs and 92 singletons) were derived by cluster assembly and sequence alignment of 200 ESTs; out of 125 unigenes, 21 (16 %) were found to be novel to moth bean. Gene ontology functional classification terms were retrieved for 98 (78.4 %) unigenes of which 73 (58.4 %) ESTs were functionally annotated (GO consensus) where 19 unigenes were annotated with 11 enzyme commission (EC) codes and were mapped to 25 different KEGG pathways. We have identified a majority of heat-shock proteins (constituting 35 % of the present library) aiding heat stress tolerance to moth bean. An expression level of 22 ESTs generated from the above SSH cDNA library was studied through semiquantitative RT-PCR assay simultaneously under 5 and 30 min of heat stress at 42 °C. 相似文献
109.
Har Mohindra Chawla Preeti Goel Richa Shukla David StC Black Naresh Kumar 《Journal of inclusion phenomena and macrocyclic chemistry》2014,80(3-4):201-207
A new calix[4]arene derivative in its cone conformation and bearing Schiff base loop at the lower rim has been synthesized and evaluated as a specific molecular probe for copper ions. The new molecular receptor 4 shows a selective visible change in color from colorless to yellow only in the presence of Cu2+ ions which was confirmed by a significant bathochromic shift (?λmax = 76 nm) in its absorption spectrum. The stoichiometry of the copper complex was calculated to be 1:1. These results may help to design more efficient chemical sensors for determining copper in biological systems. 相似文献
110.
H. M. Chawla Rahul Srivastava Satya Narayan Sahu Satish Kumar Shailesh Upreti 《Supramolecular chemistry》2013,25(9):672-683
A new class of neutral receptors based upon acylhydrazide-appended calix[4]arenes was synthesised and evaluated for recognition of anions. Detailed NMR and single-crystal X-ray analyses of one of the synthesised compounds reveal that anion recognition in such derivatives is achieved through cooperative hydrogen bond interactions. The presence of three centred NH–O and two OH–O hydrogen bonds at the lower rim of the synthesised calixarene architecture apparently helps the molecular scaffold to retain cone conformation to enable deployment of intermolecular hydrogen bonds for selective recognition of HSO4 ? ion in preference to F?, Cl?, Br?, I?, ClO4 ?, AcO? and PF6 ? ions. 相似文献