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1.
Darshan C. Kundaliya 《Solid State Communications》2004,131(8):489-491
The intermetallic compound, YRhAl, has been prepared and is found to be isomorphic with RRhAl (R=Pr, Nd, Gd, Ho and Tm) compounds crystallizing in the orthorhombic TiNiSi-type structure (space group Pnma). Heat capacity and electrical resistivity measurements in the He-3 temperature range reveal that this compound is superconducting with a transition temperature, Tc, of 0.9 K. The electronic specific heat coefficient, γ, and the Debye temperature are found to be 6.1 mJ/mol K and 197 K, respectively. The specific heat jump at the superconducting transition is found to be consistent with the BCS weak-coupling limit. This combined with the earlier observation of superconductivity in LaRhAl (Tc=2.4 K) having a different structure than that of YRhAl, suggests that the underlying structure is not very crucial for the occurrence of superconductivity in RRhAl series of compounds. 相似文献
2.
Abstract In the presence of the photosensitizer riboflavin at high fluence rates a photoproduct, most probably H2 O2 , is formed which causes negative phototaxis in the colorless flagellate Polytomella magna . The aim of this study was to find out whether H2 O2 is produced in a type I or II reaction. As has been shown, 1 O2 quenchers either do not influence the photodynamic action of riboflavin (furfuryl ethanol, DPBF, l -histidine, crocetin) or show slight quenching effects only at very high concentrations ≧ 10−2 M (DABCO, DMF, imidazole). D2 O is toxic to P. magna even in 1:1 and 1:2 mixtures with H2 O. On the other hand, the quenching effect of 1,4-benzoquinone, highly indicative for the type I pathway, is more than two orders of magnitude stronger than the one of the above mentioned 1 O2 quenchers. The results suggest that H2 O2 is produced in a type I reaction. Superoxide does not seem to be involved since superoxide dismutase does not diminish the photodynamic effect of riboflavin. 相似文献
3.
The preparation of polymer blends of poly(methyl methacrylate) and poly(vinylidene fluoride) in different weight percentages is described. Vickers microhardness measurements have been made to study the effects of load and compositional ratio of the two polymers in polyblend. It is observed that poly(vinylidene fluoride) acts as a plasticizer for poly(methyl methacrylate). Evidence of increasing and decreasing strength of polyblends has been obtained for different compositional ratios of the two polymers. 相似文献
4.
In the present article, a dataset of 63 quinoxaline derivatives were taken for antimalarial activity and pharmacophore were developed. Atom based method was used to develop a three dimensional quantitative structure activity relationship (3D-QSAR) model. On comparison of all statistical parameters, model AHRRR23 was found to be the most effective and predictive QSAR model as it satisfied all statistical parameters of a good model. The model AHRRR23 showed an adequate R2 value for the training set 0.9446, good predictive power with Q2 of 0.6409, good F- value, low SD 0.1218 value and outstanding Pearson-R values and low RMSE 0.2779 values of the model. The docking studies also gives very good results with good RMSD values. 3D QSAR, docking and ADME studies exhibits that the developed model could be employed as a potential lead for further study as antimalarial drug. 相似文献
5.
This paper describes the synthesis and characterization of aromatic diimide–diacids (DIDAS) obtained by reacting pyromellitic
dianhydride (PMDA), 4,4′-oxo diphthalic anhydride (ODA), 1,4,5,8-naphthalene tetra carboxylic dianhydride (NTDA) with excess
of 4-aminobutyric acid (B) or 6-aminohexanoic acid (H) using N,N-dimethyl formamide (DMF) as solvent. The synthesized compounds were used as curing agents to investigate the effect of structure
on the curing and thermal behaviour of diglycidyl ether of bisphenol-A (DGEBA). Structural characterization of DIDAS was done
by using FTIR, 1H-NMR, 13C-NMR spectroscopy and elemental analysis. Curing behaviour of DGEBA in the presence of aromatic DIDAS was investigated by
differential scanning calorimetry (DSC). The peak exotherm temperature (T
P) was low in the case of DIDAS synthesized from ODA and high in the case of DIDAS synthesized from NTDA. Thermal stability
of the isothermally cured DGEBA with DIDAS was investigated using dynamic thermogravimetry in nitrogen atmosphere. The char
yield was highest for resin cured with DIDAS containing NTDA. 相似文献
6.
Ramanjaneyulu GS Darshan DV Mahendar K Kantam ML Prabhakar S 《European journal of mass spectrometry (Chichester, England)》2011,17(3):265-275
A set of diastereomeric α-sulfanyl-β-amino acid derivatives, which are important building blocks for pharmaceuticals with potent biological activity, are studied by electrospray ionization tandem mass spectrometry. The collision induced dissociation (CID) spectra of [M+H](+), [M+NH(4)](+), [M+Na](+) and [M+Li](+) of the diastereomers were studied, among them the CID of [M+Na](+) and [M+Li](+) showed consistent differences in the relative abundance of characteristic ions that enabled distinction of the anti isomers from syn isomers. The decomposition pathways for the diagnostic ions were arrived at based on high-resolution mass spectrometry data, multiple mass spectrometry data, deuterium labeling experiments and the mass shift in accordance with the substituents located at different places. Loss of (R(1)-C(6)H(4)-CH=NH) and (Cat-NH-SO(2)R(2)) from [M+Cat](+), where Cat=Na and Li, and the product ions as a results of McLafferty rearrangement involving either >S=O or >C=O group were found to be diagnostic. The McLafferty rearrangement product ions involving >S=O group were more abundant in syn isomers while those involving >C=O group were more abundant in anti isomer. The selectivity observed in the decomposition of [M+Li](+) ions was found to be similar to that of [M+Na](+) ions, but in few cases the differences are marginal in the decomposition [M+Li](+) ions. 相似文献
7.
Adenine has been used as the template for the directed synthesis of 5-substituted imidazoles. A Novel intermediate involved in the cyclic operation has been characterised. 相似文献
8.
Ali I. M. Ibrahim Balqis Ikhmais Elisabet Batlle Waed K. AbuHarb Vibhu Jha Khaled T. Jaradat Rafael Jimnez Raquel Pequerul Xavier Pars Jaume Farrs Klaus Pors 《Molecules (Basel, Switzerland)》2021,26(19)
Aldehyde dehydrogenase 1A3 (ALDH1A3) has recently gained attention from researchers in the cancer field. Several studies have reported ALDH1A3 overexpression in different cancer types, which has been found to correlate with poor treatment recovery. Therefore, finding selective inhibitors against ALDH1A3 could result in new treatment options for cancer treatment. In this study, ALDH1A3-selective candidates were designed based on the physiological substrate resemblance, synthesized and investigated for ALDH1A1, ALDH1A3 and ALDH3A1 selectivity and cytotoxicity using ALDH-positive A549 and ALDH-negative H1299 cells. Two compounds (ABMM-15 and ABMM-16), with a benzyloxybenzaldehyde scaffold, were found to be the most potent and selective inhibitors for ALDH1A3, with IC50 values of 0.23 and 1.29 µM, respectively. The results also show no significant cytotoxicity for ABMM-15 and ABMM-16 on either cell line. However, a few other candidates (ABMM-6, ABMM-24, ABMM-32) showed considerable cytotoxicity on H1299 cells, when compared to A549 cells, with IC50 values of 14.0, 13.7 and 13.0 µM, respectively. The computational study supported the experimental results and suggested a good binding for ABMM-15 and ABMM-16 to the ALDH1A3 isoform. From the obtained results, it can be concluded that benzyloxybenzaldehyde might be considered a promising scaffold for further drug discovery aimed at exploiting ALDH1A3 for therapeutic intervention. 相似文献
9.
Darshan C. Kundaliya Reeta Vij D. G. Kuberkar R. G. Kulkarni 《Physica C: Superconductivity and its Applications》2000,340(4):317-322
The structural and superconducting properties of single-phase Fe-substituted La2.5Nd0.5CaBa3(Cu1−xFex)7Oz (LNCBCuFe) with 0.0x0.06 compounds having triple-perovskite structure are investigated using X-ray diffraction, a.c. susceptibility, d.c. magnetization, oxygen content and Mössbauer effect measurements. Mössbauer spectral analysis of x=0.03 sample displays unusual Fe-dopant site occupancies and the Cu(2) plane to Cu(1) chain site ratio in the LNCBCuFe are quite different from those of the usual Fe-doped YBa2Cu3O7−δ. Specifically, we observe substantial occupation of a new chain-associated quasi-octahedral site, E, at 300 K which transforms into the well-known distorted tetrahedron chain site, A, on lowering the temperature to 78 K. The observed reduction of Tc with increasing x in LNCBCuFe supports the view that the hole filling mechanism contributes predominantly to the suppression of superconductivity by Fe. 相似文献
10.
D. Bharathi B. Siddlingeshwar R. Hari Krishna Vikram Singh Nagaraju Kottam Darshan Devang Divakar Abdulaziz Abdullah Alkheraif 《Journal of fluorescence》2018,28(2):573-579
Carbon quantum dots (CQDs) due to its high fluorescent output is evolving as novel sensing material and is considered as future building blocks for nano sensing devices. Hence, in this investigation we report microwave assisted preparation and multi sensing application of CQDs. The microwave derived CQDs are characterized by Dynamic Light Scattering (DLS) experiment and Fourier Infrared spectra (FTIR) to investigate the size distribution and chemical purity respectively. Fluorescent emission spectra recorded at varying pH shows varying fluorescence emission intensities. Further, emission spectra recorded at different temperatures shows that fluorescence emission of CQDs greatly depends on temperature. Therefore, we demonstrate the pH and temperature sensing characteristics of CQDs by fluorescence quenching behaviour. In addition, the interaction and sensing behaviour of CQDs for dopamine is also presented in this work with a detection limit of 0.2 mM. The steady state and time-resolved methods have been employed in fluorescence quenching methods for sensing dopamine through CQDs at room temperature. The bimolecular quenching rate constants for different concentration have been measured. The interaction between CQDs and dopamine indicates fluorescence quenching method is an elegant process for detecting dopamine through CQDs. 相似文献