Differential and Integral Equations for Legendre–Laguerre-Based Hybrid Polynomials

Ukrainian Mathematical Journal - We study a hybrid family of three-variable Legendre–Laguerre–Appell polynomials and establish their properties, including the series expansions,...     

Solvent Free Synthesis of N‐Substituted Pyrroles Catalyzed by Calcium Nitrate

Moderated and mild way for synthesizing N‐substituted pyrrole has been demonstrated herein. No solvents need to be used for this reaction, and instead, reactants themselves acted as a reaction medium. In fact, the reaction is carried out using catalytic amount of Ca(NO₃)₂.4H₂O. The reaction conditions are selective and mild that helped to tolerate a wide variety of functional groups to give the desired products in good chemical yields.     

Surface topographical studies of prism faces of ammonium tartrate single crystals

A study of surface structures of Prism faces (110) of ammonium tartrate single crystals grown by gel technique is described and illustrated. Vertical striations closly and widely spaced are observed. Isolated as well as densely populated rectangular elongated hillocks are reported and mechanism of the growth of these faces is assessed in the light of observed surface structure.     

Defensive Mechanisms in Cucurbits against Melon Fly (Bactrocera cucurbitae) Infestation through Excessive Production of Defensive Enzymes and Antioxidants

Melon fly (Bactrocera cucurbitae) is the most common pest of cucurbits, and it directly causes damage to cucurbit fruits in the early developmental stage. The infection of fruit tissues induces oxidative damage through increased generation of cellular reactive oxygen species. The effects of melon fly infestation on the production of defensive enzymes and antioxidant capabilities in five cucurbit species, namely, bottle gourd, chayote, cucumber, snake gourd, and bitter gourd, were investigated in this study. The total phenolic and flavonoid content was considerably higher in melon fly infestation tissues compared to healthy and apparently healthy tissues. The chayote and bottle gourd tissues expressed almost 1.5- to 2-fold higher phenolic and flavonoid contents compared to the tissues of bitter gourd, snake gourd, and cucumber upon infestation. Defensive enzymes, such as peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), and catalase (CAT), were high in healthy and infected tissues of chayote and bottle gourd compared to bitter gourd, snake gourd, and cucumber. The activity of POD (60–80%), SOD (30–35%), PPO (70–75%), and CAT (40–50%) were high in infected chayote and bottle gourd tissue, representing resistance against infestation, while bitter gourd, snake gourd, and cucumber exhibited comparatively lower activity suggesting susceptibility to melon fly infection. The antioxidant properties were also high in the resistant cucurbits compared to the susceptible cucurbits. The current research has enlightened the importance of redox-regulatory pathways involving ROS neutralization through infection-induced antioxidative enzymes in host cucurbit resistance. The melon fly infestation depicts the possible induction of pathways that upregulate the production of defensive enzymes and antioxidants as a defensive strategy against melon fly infestation in resistant cucurbits.     

Investigations on Flux Grown Cadmium Sulphide Crystals

Observations on surface microtopography of flux grown CdS crystals are reported. Crystals resulting with cooling rate above 30 °C/hr are reported to be dendritic crystals, while those with cooling rate below 30 °C/hr are reported to be normal crystals like mineral greenockite as reported in standard books on mineralogy. Reasoning for dendritic growth is briefly discussed. Growth patterns and etch pits formation on them are interpreted. It is established that these crystals grow by two-dimensional nucleation mechanism and by spreading and piling of growth layers.     

Study of binding interaction of rivaroxaban with bovine serum albumin using multi-spectroscopic and molecular docking approach

Background

Rivaroxaban is a direct inhibitor of coagulation factor Xa and is used for venous thromboembolic disorders. The rivaroxaban interaction with BSA was studied to understand its PK and PD (pharmacokinetics and pharmacokinetics) properties. Multi-spectroscopic studies were used to study the interaction which included UV spectrophotometric, spectrofluorometric and three dimensional spectrofluorometric studies. Further elucidation of data was done by molecular simulation studies to evaluate the interaction behavior between BSA and rivaroxaban.

Results

Rivaroxaban quenched the basic fluorescence of BSA molecule by the process of static quenching since rivaroxaban and BSA form a complex that results in shift of the absorption spectra of BSA molecule. A decline in the values of binding constants was detected with the increase of temperatures (298–308 K) and the binding constants were in range from 1.32 × 10⁵ to 4.3 × 10³ L mol^?1 indicating the instability of the BSA and rivaroxaban complex at higher temperatures. The data of number of binding sites showed uniformity. The site marker experiments indicated site I (sub-domain IIA) as the principal site for rivaroxaban binding. The thermodynamic study experiments were carried at the temperatures of 298/303/308 K. The ?G⁰, ?H⁰ and ?S⁰ at these temperatures ranged between ? 24.67 and ? 21.27 kJ mol^?1 and the values for ?H⁰ and ?S⁰ were found to be ? 126 kJ mol^?1 and ?S ? 340 J mol^?1 K^?1 The negative value of ?G⁰ indicating spontaneous binding between the two molecules. The negative values in ?H⁰ and ?S⁰ indicated van der Waals interaction and hydrogen bonding were involved during the interaction between rivaroxaban and BSA.

Conclusions

The results of molecular docking were consistent with the results obtained from spectroscopic studies in establishing the principal binding site and type of bonds between rivaroxaban and BSA.

     

New UPLC–MS/MS method for simultaneous determination of irbesartan and hydrochlorthiazide in human plasma

Ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) is a preeminent analytical tool for rapid biomedical analysis with the objective of reducing analysis time and maintaining good efficiency. In this study a simple, rapid, sensitive and specific ultra-performance liquid chromatography–tandem mass spectrometry method was developed and validated for quantification of the angiotensin II receptor antagonist, irbesartan and hydrochlorthiazide in human plasma. After a simple protein precipitation using methanol and acetonitrile, irbesartan, hydrochlorthiazide and internal standard (IS) telmisartan were separated on Acquity UPLC BEH? C18 column (50 × 2.1 mm, i.d. 1.7 μm, Waters, USA) using a mobile phase consisting of acetonitrile:10 mM ammonium acetate:formic acid (85:15:0.1 % v/v/v) pumped at a flow rate of 0.3 mL/min and detected by tandem mass spectrometry with negative ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 427.2 → 193.08 for irbesartan, m/z 295.93 → 268.90 for hydrochlorthiazide and m/z 513.2 → 287.14 for IS. The assay exhibited a linear dynamic range of 30–500 ng/mL for irbesartan and 1–500 ng/mL in human plasma with good correlation coefficient of (0.996) and (0.997) and with a limit of quantitation of 30  and 1 ng/mL for irbesartan and hydrochlorthiazide, respectively. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 10.13 % for irbesartan and 11.14 % for hydrochlorthiazide. The proposed UPLC–MS/MS method is simple, rapid and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.     

Optical properties of some modified plant compound after 662 keV gamma radiation

Plant-isolated compounds, Osthol [7-methoxy-8-(3-methylbut-2-enyl) coumarin], were subjected to modification in the isopentenyl side chain to get an aldehyde of 2-methyl-4 (7-methoxy-2-oxo-2H-chromen-8-yl)-but-2-en-1-al. This modified compound was exposed to γ-radiation produced by ¹³⁷Cs source at room temperature. Pre- and post-irradiation study was carried out by ultraviolet–visible spectroscopy. The compound shows a sharp absorption peak at 322?nm. This observed absorption band decreases with irradiation up to a certain dose and then increases with a further increase in the radiation dose. This compound exhibits almost a linear response up to 7?Gy. From the optical data analysis, this compound follows indirect allowed transition and the optical gap was found around 3.58?eV. The systematic decrease in the band gap was found with an increase in the radiation dose. Urbach energy is also found to decrease with radiation. This parameter gives a clear indication of the defects and free radical created in the system after irradiation. The present features shown by this compound may be exploited as sensitive dosimeter in 0–7?Gy γ-radiation environment.     

A simple and effective strategy for labeling cysteine sulfenic acid in proteins by utilization of β-ketoesters as cleavable probes

β-ketoesters are robust probes for labeling sulfenic acid (-SOH) proteins allowing quantitative cleavage of the tag for improved analysis of the labeled peptides by MS.     

Influence of synthesis route on morphology and conduction behavior of BaCe<Subscript>0.8</Subscript>Y<Subscript>0.2</Subscript>O<Subscript>3−δ</Subscript>

In this article, the role of the preparation route and calcinations temperature on the thermal expansion and conductivity of BaCe_0.8Y_0.2O_3−δ (BCY) has been studied. In particular, the samples were synthesized by means of the solid-state reaction and by a sol–gel route. BCY has been suggested as proton conducting electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Proton conductivity strongly depends on the densification of the material as well as the crystal structure, which is generally influenced by the preparation procedure. It was found that a single phase material could be achieved at 1000 °C for the samples prepared through the sol–gel route with ~96% packing density. In case of ceramic route, single phase could be obtained at higher temperatures (1200 °C) and does not lead to good density values. The ceramic synthesis produces BCY material in cubic symmetry where as the gel–citrate complexation route leads to homogenous orthorhombic BCY. The conductivity measurements of sample synthesized by two different routes were investigated by means of impedance spectroscopy and electron microscopy. A comparative study of thermal expansion behavior of BCY synthesized by different route was carried out.