Identification of irradiated sage tea (Salvia officinalis L.) by ESR spectroscopy

The use of electron spin resonance (ESR) spectroscopy to accurately distinguish irradiated from unirradiated sage tea was examined. Before irradiation, sage tea samples exhibit one asymmetric singlet ESR signal centered at g=2.0037. Besides this central signal, two weak satellite signals situated about 3 mT left and right to it in radiation-induced spectra. Irradiation with increasing doses caused a significant increase in radiation-induced ESR signal intensity at g=2.0265 (the left satellite signal) and this increase was found to be explained by a polynomial varying function. The stability of that radiation-induced ESR signal at room temperature was studied over a storage period of 9 months. Also, the kinetic of signal at g=2.0265 was studied in detail over a temperature range 313–353 K by annealing samples at different temperatures for various times.     

Ortho‐Functionalized Aryltetrazines by Direct Palladium‐Catalyzed C−H Halogenation: Application to Fast Electrophilic Fluorination Reactions

A general catalyzed direct C?H functionalization of s‐tetrazines is reported. Under mild reaction conditions, N‐directed ortho‐C?H activation of tetrazines allows the introduction of various functional groups, thus forming carbon–heteroatom bonds: C?X (X=I, Br, Cl) and C?O. Based on this methodology, we developed electrophilic mono‐ and poly‐ortho‐fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s‐aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to ortho‐functionalized aryltetrazines which are difficult to obtain by classical Pinner‐like syntheses.     

The stability constants of the rare earth complexes with trimetaphosphoric acid

The stability constants of the complexes formed between the rare earth metal ions and the anion of trimetaphosphoric acid have been determined at a temperature of 20 degrees C and an ionic strength of mu = 0.1 by the ion-exchange equilibrium method. The investigations indicate that stabilities of complexes increased from La to Lu. The highest and the lowest stability constant values (beta) were found to be 7.76 and 3.82 for Lu3+ and La3+ respectively.     

A dynamic uncapacitated lot-sizing problem with co-production

We consider an extension of the dynamic uncapacitated lot-sizing problem to account for co-production, where multiple products are produced simultaneously in a single production run. We formulate the problem as a mixed-integer linear programming problem. We then show that a variant of the well-known zero-inventory property holds for this problem, and use this property to extend a dynamic program given for the single-item lot-sizing to solve the problem with co-production. Finally, we provide an illustrative example for our approach.     

A facility location model with safety stock costs: analysis of the cost of single-sourcing requirements

We consider a supply chain setting where multiple uncapacitated facilities serve a set of customers with a single product. The majority of literature on such problems requires assigning all of any given customer??s demand to a single facility. While this single-sourcing strategy is optimal under linear (or concave) cost structures, it will often be suboptimal under the nonlinear costs that arise in the presence of safety stock costs. Our primary goal is to characterize the incremental costs that result from a single-sourcing strategy. We propose a general model that uses a cardinality constraint on the number of supply facilities that may serve a customer. The result is a complex mixed-integer nonlinear programming problem. We provide a generalized Benders decomposition algorithm for the case in which a customer??s demand may be split among an arbitrary number of supply facilities. The Benders subproblem takes the form of an uncapacitated, nonlinear transportation problem, a relevant and interesting problem in its own right. We provide analysis and insight on this subproblem, which allows us to devise a hybrid algorithm based on an outer approximation of this subproblem to accelerate the generalized Benders decomposition algorithm. We also provide computational results for the general model that permit characterizing the costs that arise from a single-sourcing strategy.     

Nonlinear modulation of SH waves in an incompressible hyperelastic plate

Propagation of nonlinear shear horizontal (SH) waves in a homogeneous, isotropic and incompressible elastic plate of uniform thickness is considered. The constituent material of the plate is assumed to be generalized neo-Hookean. By employing a perturbation method and balancing the weak nonlinearity and dispersion in the analysis, it is shown that the nonlinear modulation of waves is governed asymptotically by a nonlinear Schr?dinger (NLS) equation. Then the effect of nonlinearity on the propagation characteristics of asymptotic waves is discussed on the basis of this equation. It is found that, irrespective of the plate thickness, the wave number and the mode number, when the plate material is softening in shear then the nonlinear plane periodic waves are unstable under infinitesimal perturbations and therefore the bright (envelope) solitary SH waves will exist and propagate in such a plate. But if the plate material is hardening in shear in this case nonlinear plane periodic waves are stable and only the dark solitary SH waves may exist.     

trans‐Bis­[O‐2,4‐di‐tert‐butyl­phenyl (4‐methoxy­phenyl)­di­thio­phosphonato‐κ2S,S′]­nickel(II)

In the the title compound, [Ni(C₂₁H₂₈O₂PS₂)₂], the Ni atom resides on an inversion centre and is coordinated in a square‐planar array by four S atoms, with Ni—S and P—S bond lengths of 2.2336 (12)/2.2351 (13) and 1.9910 (16)/2.0010 (17) Å, respectively. The two O‐2,4‐di‐tert‐butyl­phenyl and two 4‐methoxy­phenyl moieties adopt trans configurations about the central Ni atom.     

Synthesis,Crystallographic and Spectral Studies of 3-(4-(Phenylamino) Phenylamino)Cyclohex-2-Enone

Abstract  

The title compound, 3-(4-(phenylamino)phenylamino)cyclohex-2-enone, β-enaminone of 1,3-cyclohexanedione and p-amino diphenylamine (C₁₈H₁₈N₂O) was prepared and characterized by ¹H-NMR, ¹³C-NMR, Elemental analysis and IR spectroscopy as well as single crystal X-ray diffraction. These results indicate the predominance of the keto-enol tautomerism. Molecular conformation around the central disubstituted benzene ring is affected by the tautomerism and two steric effects between side molecular groups and mono substituted benzene ring. Electron delocalizations due to these effects have been observed in the molecular structure, the structure being stabilized by some intermolecular hydrogen bonds.     

Simultaneous determination of potassium guaiacolsulfonate, guaifenesin, diphenhydramine HCl and carbetapentane citrate in syrups by using HPLC-DAD coupled with partial least squares multivariate calibration

A simple and rapid analytical procedure was proposed for the determination of chromatographic peaks by means of partial least squares multivariate calibration (PLS) of high-performance liquid chromatography with diode array detection (HPLC-DAD). The method is exemplified with analysis of quaternary mixtures of potassium guaiacolsulfonate (PG), guaifenesin (GU), diphenhydramine HCI (DP) and carbetapentane citrate (CP) in syrup preparations. In this method, the area does not need to be directly measured and predictions are more accurate. Though the chromatographic and spectral peaks of the analytes were heavily overlapped and interferents coeluted with the compounds studied, good recoveries of analytes could be obtained with HPLC-DAD coupled with PLS calibration. This method was tested by analyzing the synthetic mixture of PG, GU, DP and CP. As a comparison method, a classsical HPLC method was used. The proposed methods were applied to syrups samples containing four drugs and the obtained results were statistically compared with each other. Finally, the main advantage of HPLC-PLS method over the classical HPLC method tried to emphasized as the using of simple mobile phase, shorter analysis time and no use of internal standard and gradient elution.     

Imaging of vascular smooth muscle cells with soft X-ray spectromicroscopy

Using X-ray microscopy and spectromicroscopy, vascular smooth muscle cells (VSMCs) were imaged, prepared without using additional embedding material or staining, but by applying simple, noncryo fixation techniques. The cells were imaged with a compact source transmission X-ray microscope and a scanning transmission X-ray microscope (STXM). With the STXM, spectromicroscopy was performed at the C K-edge and the Ca L(III,II)-edges. VSMCs were chosen because of their high amount of actin stress fibers, so that the actin cytoskeleton should be visible. Other parts of the cell, such as the nucleus and organelles, were also identified from the micrographs. Both in the spectra and the images, the effects of the different preparation procedures were observable. Furthermore, Ca hotspots were detected and their density is determined.