A review of bioanalytical methods for chronic lymphocytic leukemia drugs and metabolites in biological matrices

Quantitation of drugs used for the treatment of chronic lymphocytic leukemia in various biological matrices during both pre-clinical and clinical developments is very important, often in routine therapeutic drug monitoring. The first developed methods for quantitation were traditionally done on LC in combination with either UV or fluorescence detection. However, the emergence of LC with mass spectrometry in tandem in early 1990s has revolutionized the quantitation as it has provided better sensitivity and selectivity within a shorter run time; therefore it has become the choice of method for the analysis of various drugs. In this article, an overview of various bioanalytical methods (HPLC or LC–MS/MS) for the quantification of drugs for the treatment of chronic lymphocytic leukemia, along with applicability of these methods, is given.     

Unification of Blockchain and Internet of Things (BIoT): requirements,working model,challenges and future directions

Wireless Networks - The Internet of Things (IoTs) enables coupling of digital and physical objects using worthy communication technologies and introduces a future vision where computing systems,...     

B-GWO based multi-UAV deployment and power allocation in NOMA assisted wireless networks

Wireless Networks - Unmanned Aerial Vehicles (UAVs) deployed as flying base stations is a promising technology for enhancing the quality of service (QoS) and quick recovery from unexpected damages...     

A Robust numerical approach for singularly perturbed time delayed parabolic partial differential equations

We consider the numerical solution of a initial boundary value problem with a time delay. The problem under consideration is singularly perturbed from the mathematical perspective. Assuming that the coefficients of the differential equation are smooth, we construct and analyze the finite difference method whose solutions converge pointwise at all points of the domain independently of the singular perturbation parameter. The method permits its extension to the case of adaptive meshes, which may be used to improve the solution. Numerical examples are presented to demonstrate the effectiveness of the method. The convergence obtained in practice satisfies the theoretical predictions.     

Performance analysis of OFDM system with transmit antenna selection using delayed feedback

We consider orthogonal frequency division multiplexing (OFDM) in a multiple input single output (MISO) system. In the presence of spatially uncorrelated time-varying frequency selective channel, we use subcarrier by subcarrier antenna selection using delayed feedback. We derive closed-form expressions for the pdf of the received SNR and BER for MQAM constellation. The expressions have been obtained as a function of the correlation (ρ) between perfect channel state information (CSI) and delayed CSI, where 0 ≤ ρ ≤ 1. We have verified our analytical expressions by comparing them with simulation results. We have also reduced the BER expression for some special cases and compared them with the results available in the literature. We conclude that the diversity gain of the considered system is reduced to one for ρ < 1, i.e. not having perfect antenna selection for each subcarrier. However, we get some coding gain compared to single input single output system, the coding gain reduces with decreasing the correlation.     

Preliminary Study of Cationic Copolymerization of α-Methylstyrene and Isobutyl Vinyl Ether. II

α-Methylstyrene (α-MS) and isobutyl vinyl ether (IBVE) were copolymerized by using the H₂O/EtAlCl₂ initiator system and CH₂Cl₂ and CH₃Cl solvent in the temperature range from -30 to -90°C. As compared to homopolymerization of α-MS, both yields and molecular weights are reduced upon addition of small amounts of IBVE to the feed. The reactivity ratios were calculated by the method of Kelen and Tödös as well as the Fineman and Ross method, and the combined effect of change of solvent and temperature on reactivity ratios was determined. Effects of feed composition and temperature on the copolymer yield, composition, and number-average molecular weight M _n were studied in detail. M _n showed a novel exponential dependence on the IBVE concentration in the feed. The overall activation energies of molecular weight were determined from the Arrhenius plots for both homo-and copolymerization systems. Based on these and the yield data, a speculation is made regarding reaction mechanism for molecular weight control. NMR and DTA data are reported, which establish the random nature of the copolymers.     

Molecular Modeling and 3D-QSAR Studies in 2-Aziridinyl-and 2,3-Bis(Aziridinyl)-1,4-Naphthoquinonyl Sulfonate and Acylate Derivatives as Potential Antimalarial Agents

Abstract

Malaria is still continuing to be one of the most dreadful diseases of the tropical countries particularly due to the development of resistance to the existing antimalarials. From observed, antimalarial activity of 2-aziridinyl- and 2,3-bis(aziridinyl)-1,4-naphthoquinonyl sulfonate and acylate derivatives acting through redox cycling mechanism, molecular modeling and three dimensional-quantitative structure activity relationship (3D-QSAR) studies have been carried out on a set of 63 compounds to identify important pharmacophors. Among several 3D-QSAR models generated, three models with correlation coefficient r > 0.82, match > 0.60 and chance = 0.00 have shown two common biophoric sites: one being the oxygen atom at position 1 of the naphthoquinone ring in terms of π-population, charge and electron donating ability while the second being the center of the phenyl ring in terms of its 6π-electrons. In addition to these sites, the models also share two common secondary sites: one positively contributing H-acceptor site while the second site contributing negatively in terms of steric refractivity. All these models showed good agreement between the experimental, calculated and predicted antimalarial activities.     

Synthesis of 2, 2-Dimethyl-2H-chromenes via a Palladium (II) Catalysed Reaction

The antijuvenile hormones Precocene-I, Precocene-II and other bioactive 2, 2-dimethyl-2H-chromenes have been synthesised by intramolecular oxidative cyclisation of 2-isoprenyl phenols catalysed by a palla-dium(II) salt.     

Development of Polar Organic Mode Chromatographic Method by Polysaccharide-Based Immobilized Chiral Selector and Validation for the Determination of the Enantiopurity of Novel Mineralocorticoid Receptor Antagonist Atropisomer–Esaxerenone

Esaxerenone is a new nonsteroidal mineralocorticoid receptor antagonist utilized to treat high blood pressure. Chemically, esaxerenone is a pyrrole derivative consisting of hindered rotation, which results in stereoisomers named atropisomers. Currently, no methods exist for the separation and quantification of these atropisomers. A new and accurate chiral liquid chromatographic technique was developed and validated to estimate the enantiomeric purity of esaxerenone. Polar organic chiral separation was carried out on an immobilized amylose-based chiral stationary phase (Chiralpak IG) with methanol:acetonitrile:diethylamine (9:1:0.1, v/v/v) mixture as a mobile phase. The total runtime was 15 min, and the resolution (R_s) between the atropisomers was more than 3.0. The detection and quantification thresholds for the R-atropisomer were found to be 0.03 and 0.1 µg mL^?1, respectively, for a test concentration of esaxerenone (1000 µg mL^?1). Over the range from the limit of quantification to 0.3 percent, the method's linearity for the R-atropisomer was excellent (R²?>?0.999). The R-atropisomer recovery varied from 95 to 102%, confirming the method’s good accuracy. For a 48-h research period, the chemical was shown to be stable.

     

Sodiation Of Hard Carbon: How Separating Enthalpy And Entropy Contributions Can Find Transitions Hidden In The Voltage Profile

Sodium-ion batteries (NIBs) utilize cheaper materials than lithium-ion batteries (LIBs) and can thus be used in larger scale applications. The preferred anode material is hard carbon, because sodium cannot be inserted into graphite. We apply experimental entropy profiling (EP), where the cell temperature is changed under open circuit conditions. EP has been used to characterize LIBs; here, we demonstrate the first application of EP to any NIB material. The voltage versus sodiation fraction curves (voltage profiles) of hard carbon lack clear features, consisting only of a slope and a plateau, making it difficult to clarify the structural features of hard carbon that could optimize cell performance. We find additional features through EP that are masked in the voltage profiles. We fit lattice gas models of hard carbon sodiation to experimental EP and system enthalpy, obtaining: 1. a theoretical maximum capacity, 2. interlayer versus pore filled sodium with state of charge.