An electrochemical signal switch–based (on–off) aptasensor for sensitive detection of insulin on gold-deposited screen-printed electrodes

Journal of Solid State Electrochemistry - Insulin hormone is of great importance for many diseases, especially for diabetes management. Therefore, different detection strategies have been used for...     

Interval oscillation criteria for second order super‐half linear functional differential equations with delay and advanced arguments

Sufficient conditions are established for oscillation of second order super half linear equations containing both delay and advanced arguments of the form where ?_δ (u) = |u |^{δ –1}u; α > 0, β ≥ α, and γ ≥ α are real numbers; k, p, q, e, τ, σ are continuous real‐valued functions; τ (t) ≤ t and σ (t) ≥ t with lim_{t →∞} τ (t) = ∞. The functions p (t), q (t), and e (t) are allowed to change sign, provided that p (t) and q (t) are nonnegative on a sequence of intervals on which e (t) alternates sign. As an illustrative example we show that every solution of is oscillatory provided that either m₁ or m₂ or r₀ is sufficiently large (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Simple fabrication of hexagonally well-ordered AAO template on silicon substrate in two dimensions

In this study, thin anodic aluminum oxide (AAO) templates both on silicon substrates (AAO template/SiO₂/Si) and Ti-coated silicon substrates (AAO template/Ti/SiO₂/Si) were developed for design of magnetic, electronic and optoelectronic devices, chemical sensors and chip-scale lithium-ion rechargeable microbatteries. Two types of AAO template were prepared by using a two-step anodization procedure. The templates were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The obtained thin AAO templates were approximately 50 nm in diameter and 700 nm in length with 80-nm interpore distances in a relatively large area of 6 cm². A barrier layer of the AAO templates was removed by a cathodic polarization method in KCl solution for several seconds. The current–time transient during removing the alumina barrier layer of the thin AAO template and the mechanism of electrochemical dissolution of the barrier layer are given in detail.     

Bounded Oscillation of Nonlinear Neutral Differential Equations of Arbitrary Order

The paper is concerned with oscillation properties of n-th order neutral differential equations of the form

Controllability of the Vallée–Poussin Problem for Impulsive Differential Systems

Necessary and sufficient conditions for the controllability of multipoint boundary-value problems for linear semihomogeneous and nonhomogeneous impulsive differential systems are established. The set of all controls solving such problems is described. Moreover, we provide sufficient conditions for the time-optimal control of the Vallée–Poussin problem and obtain the Pontryagin maximum principle in sufficient form.     

On the determination of solutions of simultaneous Pell equations $$x^{2}-(a^{2}-1)y^{2}=y^{2}-pz^{2}=1$$ x 2 - ( a 2 - 1 ) y 2 = y 2 - p z 2 = 1

Periodica Mathematica Hungarica - In this paper, we consider the simultaneous Pell equations 0.1 $$\begin{aligned} x^{2}-(a^{2}-1)y^{2}= & {} 1, \nonumber \\ y^{2}-pz^{2}= & {} 1,...     

Elliptic cone optimization and primal–dual path-following algorithms

In elliptic cone optimization problems, we minimize a linear objective function over the intersection of an affine linear manifold with the Cartesian product of the so-called elliptic cones. We present some general classes of optimization problems that can be cast as elliptic cone programmes such as second-order cone programmes and circular cone programmes. We also describe some real-world applications of this class of optimization problems. We study and analyse the Jordan algebraic structure of the elliptic cones. Then, we present a glimpse of the duality theory associated with elliptic cone optimization. A primal–dual path-following interior-point algorithm is derived for elliptic cone optimization problems. We prove the polynomial convergence of the proposed algorithms by showing that the logarithmic barrier is a strongly self-concordant barrier. The numerical examples show the path-following algorithms are efficient.     

Novel Thiosemicarbazone Derivatives: In Vitro and In Silico Evaluation as Potential MAO-B Inhibitors

MAO-B inhibitors are frequently used in the treatment of neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Due to the limited number of compounds available in this field, there is a need to develop new compounds. In the recent works, it was shown that various thiosemicarbazone derivatives show hMAO inhibitory activity in the range of micromolar concentration. It is thought that benzofuran and benzothiophene structures may mimic structures such as indane and indanone, which are frequently found in the structures of such inhibitors. Based on this view, new benzofuran/benzothiophene and thiosemicarbazone hybrid compounds were synthesized, characterized and screened for their hMAO-A and hMAO-B inhibitory activity by an in vitro fluorometric method. The compounds including methoxyethyl substituent (2b and 2h) were found to be the most effective agents in the series against MAO-B enzyme with the IC₅₀ value of 0.042 ± 0.002 µM and 0.056 ± 0.002 µM, respectively. The mechanism of hMAO-B inhibition of compounds 2b and 2h was investigated by Lineweaver–Burk graphics. Compounds 2b and 2h were reversible and non-competitive inhibitors with similar inhibition features as the substrates. The K_i values of compounds 2b and 2h were calculated as 0.035 µM and 0.046 µM, respectively, with the help of secondary plots. The docking study of compound 2b and 2h revealed that there is a strong interaction between the active sites of hMAO-B and analyzed compound.     

Dinicotinamidium squarate

The crystal structure determination of the dinicotinamidium squarate salt, 2C₆H₇N₂O⁺·C₄O₄²⁻, is reported, with the squarate dianion residing on an inversion centre and the unique cation in a general position. Salt formation occurs by donation of two H atoms from squaric acid to the nicotin­amide base. The crystal packing is derived from three types of hydrogen bonding. The primary hydrogen bond involves a squarate anion O atom and an H atom of the protonated pyridine group of the nicotin­amide, with an N⋯O distance of 2.5760 (13) Å. The second hydrogen bond involves a second anion O atom and an amide H atom, with an N⋯O distance of 2.8374 (14) Å. Thirdly, an intermolecular interaction between two coplanar nicotin­amide moieties occurs between an amide O atom and a symmetry‐related amide H atom, with an N1⋯O3 distance of 2.8911 (15) Å. These hydrogen bonds are also responsible for the planarity of the nicotin­amide moiety in the salt.