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51.
M. Yadav V. Trivedi V. Upadhyay G. Shah H. Shah A. Upadhyay S. Goswami P. S. Shrivastav 《Journal of Analytical Chemistry》2014,69(5):448-460
A simple, sensitive and high throughput liquid chromatography-tandem mass spectrometry method has been developed for the determination of lafutidine in human plasma. Sample clean-up involved solid phase extraction of lafutidine along with ranitidine as the internal standard from 100 μL of human plasma. The chromatographic separation is achieved within 2.5 min on a Grace Denali C18 (50 × 4.6 mm, 5 μ) column using 2 mM ammonium acetate, pH 3.0 adjusted with acetic acid and acetonitrile (20: 80, v/v) as the mobile phase. The precursor → product ion transitions for lafutidine (m/z 432.2 → 351.4) and IS (m/z 315.3 → 176.3) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring and positive ion mode. The method is validated over a wide dynamic concentration range of 0.25–1000 ng/mL. The mean relative recovery for lafutidine across quality controls is 97.9%. The relative matrix effect between eight different plasma lots, expressed as coefficient of variation of the slopes of the calibration lines is 1.94. The method is applied to a bioequivalence study of 10 mg lafutidine tablet formulation in 26 healthy Indian male subjects under fasting condition. The reproducibility of study data is demonstrated by analysis of 93 incurred samples. 相似文献
52.
Syed Mashhood Ali Santosh Kumar Upadhyay Arti Maheshwari Mamoru Koketsu 《Journal of inclusion phenomena and macrocyclic chemistry》2006,55(3-4):325-328
1H NMR spectroscopic study of fluvastatin sodium (FLU), β-Cyclodextrin (β-CD) and their mixtures confirmed the formation of FLU/β-CD inclusion complex in solution. The stoichiometry of the complex was determined to be 1:1 and the overall binding constant (K
s) was calculated to be 340 M−1. Two dimensional COSY, ROESY and DEPTO experiments were performed for the unambiguous assignment of aromatic proton resonances and it was found that two isomeric forms of FLU are present in solution. It was confirmed with the help of ROESY spectral data that only F-substituted aromatic ring penetrates the β-CD cavity and there is chiral differentiation by the β-CD as one of the isomer binds more strongly, which is indicated by the intensity of correlation peaks. The mode of penetration of the guest into the β-CD cavity was also established and structure of the complex has been proposed. 相似文献
53.
Anand Kumar Chaudhari Vipin Kumar Singh Abhishek Kumar Dwivedy Somenath Das Neha Upadhyay Akanksha Singh 《Natural product research》2020,34(5):745-749
AbstractThe chemical characterisation of Pimenta dioica essential oil (PDEO) revealed the presence of 50 components, amongst which α-Terpineol (30.31%) was the major component followed by β-Linalool (6.75%) and γ-Terpinene (4.64%). The oil completely inhibited the growth of aflatoxin B1 secreting strain Aspergillus flavus LHP-VS-8 and aflatoxin B1 production at 2.5?µL/mL and 1.5?µL/mL, respectively. The oil caused dose dependent reduction of methylglyoxal (an AFB1 inducer), enhanced leakage of Ca2+, Mg2+ and K+ ions and significantly reduced ergosterol content of fungal plasma membrane. During in situ experiments, PDEO exhibited complete protection of fumigated maize cob slices from fungal infestation without affecting seed germination. The chemically characterised PDEO is recommended as a plant based preservative and shelf life enhancer of food commodities by preventing fungal growth, AFB1 production and lipid peroxidation. This is the first report on PDEO as inhibitor of AFB1 secretion and methylglyoxal biosynthesis. 相似文献
54.
Summary The kinetics of oxidation of aldoses, namely xylose, arabinose, galactose and glucose, by CeIV have been studied in HClO4 + H2SO4 medium and in the presence of PdII. The reactions exhibit a first order rate dependence with respect to oxidant. The rate is inversely dependent on the [HSO
inf4
sup–
][H+] ratio. The order of reaction with respect to aldose decreases at higher [aldose]. Due to the formation of a complex between CeIV and PdII, a retarding effect of [PdII] on the rate of disappearance of [CeIV] has been observed. A mechanism consistent with the observed kinetic data is proposed. 相似文献
55.
Nidhi Andhariya Bhupendra Chudasama R. V. Mehta R. V. Upadhyay 《Journal of nanoparticle research》2011,13(9):3619-3631
Core–shell nanostructures have emerged as an important class of functional materials with potential applications in diverse
fields, especially in health sciences. In this article, nanoengineering of novel magnetic colloidal dispersion containing
surface modifiable silica with a core of single domain magnetite nanoparticles loaded with photosensitizer (PS) drug “Methylene
blue” (MB) has been described. Magnetite core is produced by the well-established chemical coprecipitation technique and silica
shell is formed over it by the modified hydrolysis and condensation of TEOS (tetraethyl orthosilicate). Conditions for reaction
kinetics have been established to tailor the core–shell structures in the form of nanospheres and nanocapsules. MB is loaded
into the nanostructures by demethylation reaction. The major conclusion drawn from this study is that the synthesis route
yields stable, non-aggregated MB loaded superparamagnetic magnetite-silica nanostructures with tailored morphology, tunable
loading, and excellent magnetic properties. 相似文献
56.
Given a point on a Schubert variety in an orthogonal Grassmannian, we compute the multiplicity, more generally the Hilbert function. We first translate the problem from geometry to combinatorics by applying standard monomial theory. The solution of the resulting combinatorial problem forms the bulk of the paper. This approach has been followed earlier to solve the same problem for Grassmannians and symplectic Grassmannians. 相似文献
57.
Pavel Yu. Moshin Sudhaker Upadhyay Ricardo A. Castro 《Brazilian Journal of Physics》2017,47(4):411-418
We continue the study of finite field-dependent BRST (FFBRST) symmetry in the quantum theory of gauge fields. An expression for the Jacobian of path integral measure is presented, depending on a finite field-dependent parameter, and the FFBRST symmetry is then applied to a number of well-established quantum gauge theories in a form which incudes higher-derivative terms. Specifically, we examine the corresponding versions of the Maxwell theory, non-Abelian vector field theory, and gravitation theory. We present a systematic mapping between different forms of gauge-fixing, including those with higher-derivative terms, for which these theories have better renormalization properties. In doing so, we also provide the independence of the S-matrix from a particular gauge-fixing with higher derivatives. Following this method, a higher-derivative quantum action can be constructed for any gauge theory in the FFBRST framework. 相似文献
58.
A novel piezoelectric (PZ) immunosensor for the direct detection of malarial Plasmodium falciparum histidine rich protein-2 (PfHRP-2) antigen was developed. The mixed self-assembled monolayers (SAMs) of thioctic acid and 1-dodecanethiol were formed on gold surface of quartz crystal. Cyclic voltammetry, electrochemical impedance spectroscopy and surface Raman spectroscopy techniques were used to characterize the mixed SAMs. The rabbit anti-PfHRP-2 antibodies were coupled on mixed SAM modified gold surface of quartz crystal via NHS/EDC activation method. The PZ immunosensor was applied to detect PfHRP-2 in the linear range of 15-60 ng/ml with a detection limit of 12 ng/ml. It was also found that even after 14 days of storage, 50% of the activity still remained. Clinical human serum samples were tested with this method, and the results were in agreement with those obtained from commercially available ICT kit (NOW® Malaria). 相似文献
59.
Solanki Bal Amit Baran Sharangi Tarun Kumar Upadhyay Fahad Khan Pratibha Pandey Samra Siddiqui Mohd Saeed Hae-Jeung Lee Dharmendra K. Yadav 《Molecules (Basel, Switzerland)》2022,27(19)
Worldwide, since ages and nowadays, traditional medicine is well known, owing to its biodiversity, which immensely contributed to the advancement and development of complementary and alternative medicines. There is a wide range of spices, herbs, and trees known for their medicinal uses. Chilli peppers, a vegetable cum spice crop, are bestowed with natural bioactive compounds, flavonoids, capsaicinoids, phytochemicals, phytonutrients, and pharmacologically active compounds with potential health benefits. Such compounds manifest their functionality over solo-treatment by operating in synergy and consortium. Co-action of these compounds and nutrients make them potentially effective against coagulation, obesity, diabetes, inflammation, dreadful diseases, such as cancer, and microbial diseases, alongside having good anti-oxidants with scavenging ability to free radicals and oxygen. In recent times, capsaicinoids especially capsaicin can ameliorate important viral diseases, such as SARS-CoV-2. In addition, capsaicin provides an ability to chilli peppers to ramify as topical agents in pain-relief and also benefitting man as a potential effective anesthetic agent. Such phytochemicals involved not only make them useful and a much economical substitute to wonder/artificial drugs but can be exploited as obscene drugs for the production of novel stuffs. The responsibility of the TRPV1 receptor in association with capsaicin in mitigating chronic diseases has also been justified in this study. Nonetheless, medicinal studies pertaining to consumption of chilli peppers are limited and demand confirmation of the findings from animal studies. In this artifact, an effort has been made to address in an accessible format the nutritional and biomedical perspectives of chilli pepper, which could precisely upgrade and enrich our pharmaceutical industries towards human well-being. 相似文献
60.
R.P. Rastogi Ram Shabd B.M. Upadhyay S.B. Singh P.C. Pandey 《Journal of membrane science》1984,19(1):51-73
Photoinduced potentials and currents and photo-electroosmotic velocities were measured across cellulose acetate membranes impregnated with chlorophyll pigments. Chlorophyll was extracted by both solvent extraction, Chls, and column chromatography, Chl. Photoelectric effects in membranes prepared with the following pigments were investigated: (i) Chls-a + β-carotene, (ii) Chls-b + xanthophyll, (iii) Chls-a, (iv) Chls-b, (v) β-carotene, (vi) xanthophyll, (vii) Chls-a + anthraquinone, (viii) Chls-b + anthraquinone, (ix) Chl-a, (x) Chl-b, (xi) Chl-a + anthraquinone, (xii) Chl-b + anthraquinone, (xiii) Chl-a + benzoquinone, and (xiv) Chl-b + benzoquinone. β-Carotene, xanthophyll, Chl-a and Chl-b obrained by chromatographic separation do not show a photoinduced potential or current. However, these effects are observed when “pure” (doubly chromatographed) Chl-a or Chl-b are mixed with anthraquinone or benzoquinone. These effects are observed in systems (i), (ii), (iii), (iv), (vii) and (viii) involving Chs. Although photoinduced potentials and photoinduced currents are not observed in Chl-a or Chl-b membranes, photoelectroosmosis is still observed. p]Both photoinduced potentials and currents are found to depend on pH. When the pH is changed appropriately, Chls-a acts as photocathode while Chls-b becomes a photoanode. Photocurrents are considerably enhanced when the pH is lowered. The change of photopotential with temperature is found to be insignificant. Photoelectroosmosis is always found to be directed towards the dark side, regardless of the polarity of the electrodes. A model based on the role of plastiquinone has been proposed to explain these phenomena, which have excellent reproducibility. The model predicts that ΔpH = (pH)d — (PH)1 (where (pH)d and (pH)1 denote the pH on the dark and illuminated side of the membrane respectively) would be positive when the pH of the bathing solution is higher than approximately 7, while it would be negative for lower pH. This behaviour is observed in the case of mixture of pure Chl-a + anthraquinone and pure Chl-b + benzoquinone. The model also predicts photoelectroosmosis irrespective of the presence of plastiquinone, in agreement with experimental observation. 相似文献