Electrochemical Monitoring of Methotrexate Anticancer Drug in Human Blood Serum by Using in situ Solvothermal Synthesized Fe3O4/ITO Electrode

Here, we reported on a one‐step fabrication of magnetite Fe₃O₄ nanoparticles/indium tin oxide (ITO) electrode based on the direct growing of Fe₃O₄ nanoparticles on the ITO surface by using a solvothermal process. The modified electrode was used as electrochemical methotrexate (MTX) biosensor with high sensitivity based on cyclic voltammetry and square wave voltammetry techniques. The results demonstrated a linear relationship between the MTX concentration and its oxidation current peak over a wide range from 10^?5 to 10^?14 mole/L with a limit of detection of 0.4×10^?15 M based on the square wave voltammetry (SWV) technique. In addition, Fe₃O₄/ITO electrode showed a good capability for measuring very low concentrations of MTX drug dissolved in human serum solution. Also, Fe₃O₄/ITO electrode was used for detecting MTX in blood serum samples collected from patients after their treatment with MTX. The prepared electrode showed the higher sensitivity that higher than the Viva‐E instrument, which opens the door for developing a cheap, simple and higher sensitive MTX sensor.     

On the complexity of extending the convergence ball of Wang’s method for finding a zero of a derivative

Ball convergence results are very important, since they demonstrate the complexity in choosing initial points for iterative methods. One of the most important problems in the study of iterative methods is to determine the convergence ball. This ball is small in general restricting the choice of initial points. We address this problem in the case of Wang’s method utilized to determine a zero of a derivative. Finding such a zero has many applications in computational fields, especially in function optimization. In particular, we find the convergence ball of Wang’s method using hypotheses up to the second derivative in contrast to earlier studies using hypotheses up to the fourth derivative. This way, we also extend the applicability of Wang’s method. Numerical experiments used to test the convergence criteria complete this study.     

On coloring numbers of graph powers

The weak $r$-coloring numbers ${\mathrm{wcol}}_r\left(G\right)$ of a graph $G$ were introduced by the first two authors as a generalization of the usual coloring number $\mathrm{col}\left(G\right)$, and have since found interesting theoretical and algorithmic applications. This has motivated researchers to establish strong bounds on these parameters for various classes of graphs.Let $G^p$ denote the $p$th power of $G$. We show that, all integers $p>0$ and $\Delta \ge 3$ and graphs $G$ with $\Delta \left(G\right)\le \Delta$ satisfy $\mathrm{col}\left(G^p\right)\in O\left(p\cdot {\mathrm{wcol}}_{\lceil p∕2\rceil }\left(G\right){(\Delta -1)}^{\lfloor p∕2\rfloor }\right)$; for fixed tree width or fixed genus the ratio between this upper bound and worst case lower bounds is polynomial in $p$. For the square of graphs $G$, we also show that, if the maximum average degree $2k-2<\mathrm{mad}\left(G\right)\le 2k$, then $\mathrm{col}\left(G^2\right)\le (2k-1)\Delta \left(G\right)+2k+1$.     

A review of mobility metrics for next generation vehicle mobility models

In the United States, the NATO Reference Mobility Model (NRMM) has been used for evaluating military ground vehicle mobility and the Vehicle Cone Index (VCI) has been selected as a mobility metric. VCI represents the minimum soil strength required for a vehicle to consistently make a specific number of passes, usually one or fifty passes. In the United Kingdom, the Mean Maximum Pressure (MMP) has been adopted as a metric for assessing military vehicle cross-country mobility. MMP is the mean value of the maxima occurring under all the wheel stations of a vehicle. Both VCI and MMP are empirically based. This paper presents a review of the basis upon which VCI and MMP were developed, as well as their applications to evaluating vehicle mobility in practice. With the progress in terramechanics and in modelling and simulation techniques in recent years, there is a growing desire to develop physics-based mobility metrics for next generation vehicle mobility models. Based on the review, criteria for selecting physics-based mobility metrics are proposed. Following these criteria, metrics for characterizing military vehicle traction limits and traversability on a given operating area are recommended.     

Host-guest Assembly Based on γ-Cyclodextrin-functionalized Multiwalled Carbon Nanotubes for Rutin Electrochemical Sensing

Here, we report multiwalled carbon nanotubes (MWCNTs) functionalized with γ-cyclodextrins (γCD) as a novel electrochemical strategy for Rutin determination, showing superior performance than β-cyclodextrins (βCD) modified MWCNTs, suggesting an adequate environment for host-guest interactions. Under optimized conditions, the sensor showed a linear range of 39–975 nmol L⁻¹ and a limit of detection of 7 nmol L⁻¹. When tested with quercetin, catechin, and caffeine, the platform presented high selectivity with an interference response <10 %. The method was employed to quantify Rutin in spiked pharmaceutical and herbal extracts, providing recovery of 93–98.4 %. Also, HPLC-PDA confirmed the method‘s accuracy.     

Co-detection of Copper and Lead in Artisanal Sugarcane Spirit Using Caffeic Acid-modified Graphite Electrodes

Caffeic acid (CA)-modified graphite electrodes [GE/poly(CA)] was applied to the co-detection of copper and lead in artisanal sugarcane spirit using square-wave anodic stripping voltammetry (SWASV). Electrochemical and morphological studies were performed, and a mechanism for polymerization was proposed. Electropolymerization, SWASV, and analysis conditions parameters were optimized. Interferents, repeatability, reproducibility, and addition and recovery tests were carried out. GE/poly(CA) shows a linear range from 15 to 705 μg/L with a limit of detection of 3.01 μg/L for Pb(II) and 4.50 μg/L for Cu(II). Real samples of artisanal sugarcane spirit were used, and the electrochemical results were compared with atomic absorption spectroscopy experiments.