Selective extraction of apixaban from plasma by dispersive solid-phase microextraction using magnetic metal organic framework combined with molecularly imprinted polymer nanocomposite

This research aims to synthesize a specific and efficient sorbent to use in the extraction of apixaban from human plasma samples and its determination by high-performance liquid chromatography-tandem mass spectrometry. High specific surface area of metal-organic framework, magnetic property of iron oxide nanoparticles, selectively of molecular imprinted polymer toward the analyte, and the combination of dispersive solid-phase extraction method with a sensitive analysis system provided an efficient analytical method. In this study, first, a molecularly imprinted polymer combined with magnetic metal organic framework nanocomposite was prepared and then characterized using different techniques. Then the sorbent particles were used for selective extraction of the analyte from plasma samples. The efficiency of the method was improved by optimizing effective parameters. According to the validation results, wide linear range (1.02–200 ng mL⁻¹), acceptable coefficient of determination (0.9938), low limit of detection (0.32 ng mL⁻¹) and limit of quantification (1.02 ng mL⁻¹), high extraction recovery (78%), and good precision (relative standard deviations ≤ 2.9% for intra- (n = 6) and interday (n = 6) precisions) were obtainable using the proposed method. These outcomes showed the high potential of the proposed method for screening apixaban in the human plasma samples.     

von Neumann–Schatten Dual Frames and their Perturbations

In this paper, we discuss the dual of a von Neumann–Schatten p-frames in separable Banach spaces and obtain some of their characterizations. Moreover, we present a classical perturbation result to von Neumann–Schatten p-frames.     

Analysis of a meshless method for the time fractional diffusion-wave equation

In this paper a numerical technique is proposed for solving the time fractional diffusion-wave equation. We obtain a time discrete scheme based on finite difference formula. Then, we prove that the time discrete scheme is unconditionally stable and convergent using the energy method and the convergence order of the time discrete scheme is \(\mathcal {O}(\tau ^{3-\alpha })\). Firstly, we change the main problem based on Dirichlet boundary condition to a new problem based on Robin boundary condition and then, we consider a semi-discrete scheme with Robin boundary condition and show when \(\beta \rightarrow +\infty \) solution of the main semi-discrete problem with Dirichlet boundary condition is convergent to the solution of the new semi-discrete problem with Robin boundary condition. We consider the new semi-discrete problem with Robin boundary condition and use the meshless Galerkin method to approximate the spatial derivatives. Finally, we obtain an error bound for the new problem. We prove that convergence order of the numerical scheme based on Galekin meshless is \(\mathcal {O}(h)\). In the considered method the appeared integrals are approximated using Gauss Legendre quadrature formula. The main aim of the current paper is to obtain an error estimate for the meshless Galerkin method based on the radial basis functions. Numerical examples confirm the efficiency and accuracy of the proposed scheme.     

Magnetic nanoparticles (Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> &amp; Co<Subscript>3</Subscript>O<Subscript>4</Subscript>) and their applications in urea biosensing

Nanobiotechnology has opened a new and exciting opportunities for exploring urea biosensor based on magnetic nanoparticles (NPs) mainly Fe₃O₄ and Co₃O₄. These NPs have been extensively exploited to develop biosensors with stability, selectivity, reproducibility and fast response time. This review gives an overview of the development of urea biosensor based on Fe₃O₄ and Co₃O₄ for in vitro diagnostic applications along with significant improvements over the last few decades. Additionally, effort has been made to elaborate properties of magnetic nanoparticles (MNPs) in biosensing aspects. It also gives details of recent developments in hybrid nanobiocomposite based urea biosensor.     

Investigation of curing kinetics of epoxy resin/novel nanoclay–carbon nanotube hybrids by non-isothermal differential scanning calorimetry

Chemical hybrid of nanoclay (NC)/carbon nanotube (CNT) was synthesized via growth of CNTs by chemical vapor deposition. The cure kinetics of epoxy resin in the presence of novel chemical hybrid of NC/CNT (CNC) was studied by non-isothermal differential scanning calorimetry. The effect of the CNC on cure kinetics was compared with conventional nanofillers such as CNTs, NC, and physical mixture of them (PNC). The kinetic parameters of the cure reaction were determined by iso-conversional method. The accelerating effect of CNT, CNC, and PNC in initial stage of cure reaction was related to the high thermal conductivity of CNTs, while the decelerating effect of nanofillers as the cure proceeded can be attributed to the reduction of polymer molecules motion caused by enhanced viscosity. The apparent activation energy (E _α) as the function of conversion (α) was calculated by five methods categorized into two different types: (1) conversion-dependent methods: Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW), and Friedman; (2) conversion-independent methods: Kissinger and Augis. The accelerating effect of CNT, PNC, and CNC was observable as the reduced E _α values in low conversion only with KAS and OFW methods. The reverse trend of E _α values was observed with the introduction of these nanofillers at high conversions. The uniqueness of the CNC was more marked in increasing E _α values of epoxy after initial stage due to its special 3D structure of CNC. Calculated data using KAS and OFW methods showed the best agreement with the obtained experimental data.     

Solving unsteady Korteweg–de Vries equation and its two alternatives

This paper aims to present the generalized Kudryashov method to find the exact traveling wave solutions transmutable to the solitary wave solutions of the ubiquitous unsteady Korteweg–de Vries equation and its two famed alternatives, namely, the regularized long‐wave equation and the time regularized long‐wave equation. The exact analytic solutions of the studied equations are constructed explicitly in three forms, namely, hyperbolic, trigonometric, and rational function. The validity of our solutions is verified with MAPLE by putting them back into the original equation and found correct. Moreover, it has shown that the generalized Kudryashov method is an easy and reliable technique over the existing methods. Copyright © 2016 John Wiley & Sons, Ltd.     

Two New Spirostanol Glycosides from Cestrum parqui

Two new steroidal glycosides, parquisoside A ( 1 ) and B ( 2 ) were isolated from the aerial parts of Cestrum parqui (family Solanaceae). Their common aglycone is a new steroid of the spirostane series, which we name parquigenin. It has the structure (3β,24S,25S)‐spirost‐5‐ene‐3,24‐diol, i.e. a (24S,25S)‐24‐hydroxydiosgenin. The structures of parquisosides A and B were elucidated as (3β,24S,25S)‐spirost‐5‐ene‐3,24‐diol 3‐O‐{[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl‐(1→4)}‐β‐D ‐glucopyranoside ( 1 ) and (3β,24S,25S)‐spirost‐5‐ene‐3,24‐diol 3‐O‐{[α‐L ‐rhamnopyranosyl)‐(1→4)‐α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐rhamnopyranosyl‐(1→4)}‐β‐D ‐glucopyranoside ( 2 ), respectively, on the basis of detailed spectroscopic studies and chemical analysis. The crude extract of Cestrum parqui showed inhibition of carrageenin‐induced edema.     

Enrichment of Zinc and Iron Micronutrients in Lentil (Lens culinaris Medik.) through Biofortification

Biofortification of pulse crops with Zn and Fe is a viable approach to combat their widespread deficiencies in humans. Lentil (Lens culinaris Medik.) is a widely consumed edible crop possessing a high level of Zn and Fe micronutrients. Thus, the present study was conducted to examine the influence of foliar application of Zn and Fe on productivity, concentration, uptake and the economics of lentil cultivation (LL 931). For this, different treatment combinations of ZnSO₄·7H₂O (0.5%) and FeSO₄·7H₂O (0.5%), along with the recommended dose of fertilizer (RDF), were applied to the lentil. The results of study reported that the combined foliar application of ZnSO₄·7H₂O (0.5%) + FeSO₄·7H₂O (0.5%) at pre-flowering (S1) and pod formation (S2) stages was most effective in enhancing grain and straw yield, Zn and Fe concentration, and uptake. However, the outcome of this treatment was statistically on par with the results obtained under the treatment ZnSO₄·7H₂O (0.5%) + FeSO₄·7H₂O (0.5%) at S1 stage. A single spray of ZnSO₄·7H₂O (0.5%) + FeSO₄·7H₂O (0.5%) at S1 stage enhanced the grain and straw yield up to 39.6% and 51.8%, respectively. Similarly, Zn and Fe concentrations showed enhancement in grain (10.9% and 20.4%, respectively) and straw (27.5% and 27.6% respectively) of the lentil. The increase in Zn and Fe uptake by grain was 54.8% and 68.0%, respectively, whereas uptake by straw was 93.6% and 93.7%, respectively. Also the benefit:cost was the highest (1.96) with application of ZnSO₄·7H₂O (0.5%) + FeSO₄·7H₂O (0.5%) at S1 stage. Conclusively, the combined use of ZnSO₄·7H₂O (0.5%) + FeSO₄·7H₂O (0.5%) at S1 stage can contribute significantly towards yield, Zn and Fe concentration, as well as uptake and the economic returns of lentil to remediate the Zn and Fe deficiency.     

New Cycloartane and Flavonol Glycosides from Corchorus depressus

Two new monodesmosidic cycloartane triterpene glycosides, depressosides E and F, and two new flavonol glycosides, depressonol A and B, were isolated from the butanol‐soluble part of the EtOH extract of Corchorus depressus L . The structures of the new compounds were elucidated as (22R,24S)‐22,25‐epoxy‐9,19‐cyclolanostane‐3β,16β,24‐triol 3‐[α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranoside] ( 1 ), (22R,24S)‐22,25‐epoxy‐9,19‐cyclolanostane‐3β,16β,24‐triol 3‐[α‐D ‐glucopyranosyl‐(1→3)‐β‐D ‐glucopyranoside] ( 2 ), kaempferol 3‐[β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranoside] 7‐[α‐L ‐arabinofuranoside] ( 4 ), and kaempferol 3‐[β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐galactopyranoside] 7‐[α‐L ‐arabinofuranoside] ( 5 ) on the basis of chemical evidence and detailed spectroscopic studies.