Study of the thermoluminescence dosimetric properties of window glass

This paper presents the main thermoluminescence (TL) dosimetric characteristics of commercial Turkish transparent window glass. The structure of the glow curves, including the number of peaks, was found to be dose-dependent. A low-temperature glow peak that at 160 °C shifts to higher temperatures was also observed with increasing storage time at room temperature. This result suggests that this TL glow peak is actually made up of two or more overlapping peaks. These we have attributed to the glow peaks at lower temperatures, which decay faster than the ones at higher temperatures with storage time. The thermal fading of the window glass sample at room temperature showed a relatively sharp decay of about 60% occurring over a period of 28 days, after which the decay rate is small for a measured period of 250 days. In order to the improve the post-irradiation stability of the glow curve, the glass samples were heated after irradiation. To remove the unstable TL peaks responsible for the initial rapid fading, post-irradiation heating at 160 °C for 10 min was found to be the most suitable procedure. The dosimetric characteristics of the post-irradiation heated window glass examined in this study include fading, gamma photon dose-response, reproducibility, batch sensitivity, humidity influence, a dose-rate effect and photon energy response. Dose-response was found to be appropriate for dosimetry in the range 5 Gy to 10 kGy. The post-irradiation heating procedure did not affect the main dosimetric characteristics of the window glass samples. The results in this work suggest that the materials could, by using the TL technique, be a suitable candidate for alternative dose measurements in radiation processing, provided that a judicious choice of the post-irradiation heat temperature is made to minimize fading.     

Hopf bifurcation analysis of a general non-linear differential equation with delay

This work represents Hopf bifurcation analysis of a general non-linear differential equation involving time delay. A special form of this equation is the Hutchinson–Wright equation which is a mile stone in the mathematical modeling of population dynamics and mathematical biology. Taking the delay parameter as a bifurcation parameter, Hopf bifurcation analysis is studied by following the theory in the book by Hazzard et al. By analyzing the associated characteristic polynomial, we determine necessary conditions for the linear stability and Hopf bifurcation. In addition to this analysis, the direction of bifurcation, the stability and the period of a periodic solution to this equation are evaluated at a bifurcation value by using the Poincaré normal form and the center manifold theorem. Finally, the theoretical results are supported by numerical simulations.     

Iron(III) complex of a tridentate <Emphasis Type="Italic">NNN</Emphasis> type ligand: synthesis,X-ray structure,thermal analysis and voltammetric studies

A mononuclear iron(III) complex with 2,6-bis(3,4,5-trimethyl-N-pyrazolyl)pyridine (btmpp) has been synthesized, and characterized by X-ray crystallography, IR, UV–Vis and TGA–DTA methods. The Fe(III/II) couple was characterized by way of cyclic voltammetry using DMF solvent, where the complex was observed to have an irreversible behaviour.     

Crystallographic and conformational analysis of 2-methyl-3-(2-nitro-phenyl)-4-phenyl-[1,2,4]oxadiazolidin-5-one

Molecular and crystal structure of 2-methyl-3-(2-nitro-phenyl)-4-phenyl-[1,2,4]oxadiazolidin-5-one, C₁₅H₁₃N₃O₄, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 10.0313(8) Å, b = 9.0372(5) Å, c = 15.5964(14) Å, β = 96.926(7)^∘, Z = 4, D_x = 1.42 g/cm³, μ (Mo-K_α) = 0.105 mm⁻¹, and space group is P 2₁/c. The structure was solved by direct methods and refined to a final R = 0.036 for 1894 reflections with I > 4σ (I). The crystal structure is stabilized by C–H⋅sO type inter-molecular, C–H⋅sN and C–H⋅sO type intra-molecular, π–π stacking and edge to face (C–H⋅s π-ring) interactions. To enlighten conformational flexibility of the title molecule, selected two torsion angles are varied from −180^∘ to +180^∘ in every 10^∘ separetely and then molecular energy profile is calculated and construed.     

A Novel 1D Coordination Polymer [Pb(phen)(μ‐N3)(μ‐NO3)]n with the First Pb2‐(μ‐N3)2 Unit (phen = 1,10‐phenanthroline)

A novel 1D polymeric lead(II) complex containing the first Pb₂‐(μ‐N₃)₂ motif, [Pb(phen)(μ‐N₃)(μ‐NO₃)]_n (phen = 1,10‐phenanthroline), has been synthesized and characterized. The single‐crystal X‐ray data showed the coordination number of Pb²⁺ ions to be eight (PbN₄O₄) with the Pb²⁺ ions having “stereo‐chemically active” electron lone pairs; the coordination sphere is hemidirected. The chains interact with each other via π‐π interactions to create a 3D framework.     

Synthesis,Configuration, and Antimicrobial Properties of Novel Substituted and Cyclized ‘2′,3″‐Thiazachalcones’

Nine new thiazachalcone‐based drugs, compounds 1 – 9 , were prepared and fully characterized. The configurations of the photochemical‐dimerization products 7 – 9 were rationalized by semi‐empirical calculations. Both the experimental data and the theoretical calculations showed that the δ‐truxinic acid type dimer is the most stable isomer of all. All compounds were tested for their antibacterial and antifungal activities. The N‐alkylated congeners 4 – 6 showed strong antimicrobial activities against various bacteria and a yeast‐like fungus. The MIC and MBC values were as low as 0.1 μg/ml. All the compounds were active against the Gram‐positive bacterium Staphylococcus aureus.     

A capped trigonal prismatic cadmium complex with tetra‐ and tridentate ligands: bis­(tri­ethanol­amine)‐κ3N,O,O′;κ4N,O,O′,O′′‐cadmium(II) squarate monohydrate

In the crystal structure of the title compound, [Cd(C₆H₁₅NO₃)₂](C₄O₄)·H₂O, a supramolecular structure is observed. The asymmetric unit consists of one unit of the cationic Cd complex, one water mol­ecule and two half‐squarate anions, each sitting on a crystallographic inversion center. The different coordinations of the two triethanolamine (TEA) ligands results in an unusual example of coordination number seven for the Cd^II ion. Both TEA ligands coordinate to the Cd^II ion, forming a distorted monocapped trigonal prismatic geometry with approximate C_2v symmetry. One of the TEA ligands acts as an N,O,O′‐tridentate ligand, whereas the other behaves as an N,O,O′,O′′‐tetradentate donor. The anions and cations are linked to one another by hydrogen bonds between hydroxy H atoms of the TEA ligands and squarate O atoms. The crystal structure is stabilized by O—H⋯O hydrogen bonds between the unligated water mol­ecule and a squarate O atom, together with a weak π–ring interaction between the ethyl­ene group of a TEA ligand and a squarate anion.     

Existence and Hyers–Ulam stability of solutions for a delayed hyperbolic partial differential equation

Periodica Mathematica Hungarica - In this paper, we first prove the existence and uniqueness of the solutions for a delayed hyperbolic partial differential equation by applying the progressive...     

Optimization of a validated stability‐indicating RP‐LC method for the determination of fulvestrant from polymeric based nanoparticle systems,drugs and biological samples

Fulvestrant is used for the treatment of hormone receptor‐positive metastatic breast cancer in postmenopausal women with disease progression following anti‐estrogen therapy. Several reversed‐phase columns with variable silica materials, diameters, lengths, etc., were tested for the optimization study. A good chromatographic separation was achieved using a Waters X‐Terra RP₁₈ column (250 × 4.6 mm i.d. × 5 µm) and a mobile phase, consisting of a mixture of acetonitrile–water (65:35; v/v) containing phosphoric acid (0.1%). The separation was carried out 40°C with detection at 215 nm.The calibration curves were linear over the concentration range between 1.0–300 and 1.0–200 µg/mL for standard solutions and biological media, respectively. The proposed method is accurate and reproducible. Forced degradation studies were also realized. This fully validated method allows the direct determination of fulvestrant in dosage form and biological samples. The average recovery of the added fulvestrant amount in the samples was between 98.22 and104.03%. The proposed method was also applied for the determination of fulvestrant from the polymeric‐based nanoparticle systems. No interference from using polymers and other excipients was observed in in vitro drug release studies. Therefore an incorporation efficiency of fulvestrant‐loaded nanoparticle could be determined accurately and specifically. Copyright © 2014 John Wiley & Sons, Ltd.     

Scalars, vectors and tensors from metric-affine gravity

The metric-affine gravity provides a useful framework for analyzing gravitational dynamics since it treats metric tensor and affine connection as fundamentally independent variables. In this work, we show that, a metric-affine gravity theory composed of the invariants formed from non-metricity, torsion and curvature tensors can be decomposed into a theory of scalar, vector and tensor fields. These fields are natural candidates for the ones needed by various cosmological and other phenomena. Indeed, we show that the model accommodates TeVeS gravity (relativistic modified gravity theory), vector inflation, and aether-like models. Detailed analyses of these and other phenomena can lead to a standard metric-affine gravity model encoding scalars, vectors and tensors.