Application of Impedimetric and Voltammetric Genosensor for Detection of a Biological Warfare: Anthrax

A strategy for the detection of anthrax, which is a potential biological weapon by using an electrochemical genosensing technology, is investigated. An alkanathiol‐linked or unlabeled capture probe related to B. anthracis is immobilized onto gold or graphite electrode surface. A 101‐mer anthrax target is used for hybridization. The extent of hybridization between probe and target sequences is determined by using differential pulse voltammetry (DPV) and electrochemical impedance spectrometry (EIS). EIS analysis are based on electron transfer resistance (R_ct) in the presence of [Fe(CN)₆]^3?/4? and DPV measurements are based on transduction of both guanine oxidation and Meldola's blue (MDB) reduction signal as hybridization indicator. The response of the probe‐modified electrodes which was interacted with a noncomplementary sequence was the same as the responses of probe‐modified surface and proved the specifity of the hybridization with the target. According to these results the developed genosensors based on EIS and DPV techniques can be employed for rapid and selective detection of B. anthracis.     

Resonant tunneling properties of inverted Morse double quantum barrier

We study resonant tunneling characteristics of inverted Morse double quantum barrier structures. The effect of electric bias and structure parameters is calculated by using non-equilibrium Green's function method. Results for the transmission coefficients are compared with the structure parameters. Our results show that the widths of the wells and heights of barriers have a significant effect on the transmission properties. We found that the resonant peak of the transmission coefficient decreases with increasing electric field bias. Moreover, resonant energy level increases with increasing barrier height and increasing width parameters.     

Bright,dark optical and other solitons to the generalized higher-order NLSE in optical fibers

In this paper, we study the generalized higher-order nonlinear Schrödinger equation analytically. We use two integral schemes for conducting this study. Dark, bright, combined dark–bright optical, singular soliton, soliton-like and trigonometric function solutions are successfully constructed. We give the constraint conditions for the existence of valid solutions. The 2D, 3D and the contour graphs for the dark and bright solitons are plotted.     

Dynamic phase transition in the kinetic spin-2 Blume–Emery–Griffiths model in an oscillating field

We extend our recent paper [M. Keskin, O. Canko, M. Erta?, J. Exp. Theor. Phys. (Sov. Phys. JETP) 105 (2007) 1190.] to present a study, within a mean-field approach, the stationary states of the kinetic spin-2 Blume–Emery–Griffiths model in the presence of a time-dependent oscillating magnetic field by using the Glauber-type of stochastic dynamics. We found 20 fundamental types of dynamic phase diagrams where exhibit more complex and richer phase diagrams than our recent paper. Especially, the obtained dynamic phase diagrams show the dynamic triple, quadruple and dynamic double critical end points besides dynamic tricritical points that depending on interaction parameters. The phase diagrams also exhibit a disordered (d) and the ferromagnetic-2 (f₂) phases, and the f₂+d, f₂+fq, fq+d, f₂+f₁+fq and f₂+fq+d, where f₁ are fq the ferromagnetic-1 and ferroquadrupolar or simply quadrupolar phases respectively, coexistence phase regions that strongly depend on interaction parameters.     

Characterization of Airborne Particles and Droplets:

Water sprays have been commonly used to suppress airborne dust. Water is doped with surface‐active agents to enhance the dust capture efficiency through a reduction of surface tension. Nevertheless, dust collection efficiencies have been less than satisfactory historically.     

Screening of Carbonic Anhydrase,Acetylcholinesterase, Butyrylcholinesterase,and α-Glycosidase Enzyme Inhibition Effects and Antioxidant Activity of Coumestrol

Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in plants. In this study, antiglaucoma, antidiabetic, anticholinergic, and antioxidant effects of Coumestrol were evaluated and compared with standards. To determine the antioxidant activity of coumestrol, several methods—namely N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD^•+)-scavenging activity, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^•+)-scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•)-scavenging activity, potassium ferric cyanide reduction ability, and cupric ion (Cu²⁺)-reducing activity—were performed. Butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants for comparison. Coumestrol scavenged the DPPH radical with an IC₅₀ value of 25.95 μg/mL (r²: 0.9005) while BHA, BHT, Trolox, and α-Tocopherol demonstrated IC₅₀ values of 10.10, 25.95, 7.059, and 11.31 μg/mL, respectively. When these results evaluated, Coumestrol had similar DPPH^•-scavenging effect to BHT and lower better than Trolox, BHA and α-tocopherol. In addition, the inhibition effects of Coumestrol were tested against the metabolic enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which are associated with some global diseases such as Alzheimer’s disease (AD), glaucoma, and diabetes. Coumestrol exhibited K_i values of 10.25 ± 1.94, 5.99 ± 1.79, 25.41 ± 1.10, and 30.56 ± 3.36 nM towards these enzymes, respectively.     

Development of a Novel Class of Pyridazinone Derivatives as Selective MAO-B Inhibitors

Sixteen compounds (TR1–TR16) were synthesized and evaluated for their inhibitory activities against monoamine oxidase A and B (MAOs). Most of the derivatives showed potent and highly selective MAO-B inhibition. Compound TR16 was the most potent inhibitor against MAO-B with an IC₅₀ value of 0.17 μM, followed by TR2 (IC₅₀ = 0.27 μM). TR2 and TR16 selectivity index (SI) values for MAO-B versus MAO-A were 84.96 and higher than 235.29, respectively. Compared to the basic structures, the para-chloro substituent in TR2 and TR16 increased the inhibitory activity of MAO-B. TR2 and TR16 were reversible MAO-B inhibitors that were competitive, with K_i values of 0.230 ± 0.004 and 0.149 ± 0.016 µM, respectively. The PAMPA method indicated that compounds TR2 and TR16 had the tendency to traverse the blood–brain barrier. Docking investigations revealed that lead compounds were beneficial for MAO-B inhibition via association with key as well as selective E84 or Y326 residues, but not for MAO-A inhibition via interaction primarily driven by hydrophobic contacts. In conclusion, TR2 and TR16 are therapeutic prospects for the management of multiple neurodegenerative diseases.     

The [Sn5]2– Cluster Compound [K‐(2,2,2‐crypt)]2Sn5 – Synthesis,Crystal Structure,Raman Spectrum,and Hierarchical Relationship to CaIn2

Dark red crystals of [K‐(2,2,2)‐crypt)]₂Sn₅ precipitate after the reaction of (2,2,2)‐crypt with a solution of K_1.33Sn in liquid ammonia at room temperature. The compound is sensitive to oxidation and hydrolysis. The sequence of Raman bands (104, 120, 133 and 180 cm^–1) is characteristic for the trigonal bipyramidal closo‐[Sn₅]^2– cluster anion. The wave numbers correspond with the data from Hartree‐Fock calculations (114, 128, 142 and 187 cm^–1). The compound crystallizes trigonally (a = 11.736 Å, c = 22.117 Å, Z = 2, space group P3c1 (No. 165); Pearson code hP262), isotypic with [Na‐(2,2,2)‐crypt)]₂Pb₅. The atoms of the cluster show strange anisotropic displacements, which are perfectly reducible to a helical rigid‐body motion around and along [001] (libration: ± 9.5°; translation ± 0.29 Å). The structure can be described as a hierarchical derivative of the initiator CaIn₂ (P6₃/mmc, hP6), generated by an atom‐to‐aggregate replacement: [Ca][In]₂ = [Sn₅][K @ C₃₆H₇₂N₄O₁₂]₂. Thus, the distribution of the [Sn₅]^2– Zintl anions is hexagonal primitive, and the cation complexes are located close to the centers of trigonal superprisms formed by Sn₅ clusters.