Spectroscopic Application of Realgar Using X-ray Fluorescence and Raman Spectroscopy

ABSTRACT

Samples of realgar ore were collected from the hydrothermal products of the Eocene volcanic material of the Erzurum region in Turkey. The prepared samples were analyzed by polarized energy dispersive X-ray fluorescence (PEDXRF) and by confocal Raman spectroscopy (CRS). The goal of this study was to figure out the chemical composition of realgar and its properties through PEDXRF and CRS and the optical characteristic features under the polarized microscope. The result of the XRF analysis shows the collected realgar samples are mainly composed of As, S, Si, and Mg in different proportions. The contents of As in realgar change from 36.55% through 31.49% to 5.97% in the analyzed samples. The strong peak of the realgar samples is at 352 cm^?1, and a weaker peak exists around 190 cm^?1. The accuracy and precision of the technique for chemical analysis is demonstrated by analyzing CRM 2126-81. The realgar ores were studied by use of CRS and polarized microscopy.     

The spacetime of double field theory: Review,remarks, and outlook

We review double field theory (DFT) with emphasis on the doubled spacetime and its generalized coordinate transformations, which unify diffeomorphisms and b‐field gauge transformations. We illustrate how the composition of generalized coordinate transformations fails to associate. Moreover, in dimensional reduction, the O(d,d) T‐duality transformations of fields can be obtained as generalized diffeomorphisms. Restricted to a half‐dimensional subspace, DFT includes ‘generalized geometry’, but is more general in that local patches of the doubled space may be glued together with generalized coordinate transformations. Indeed, we show that for certain T‐fold backgrounds with non‐geometric fluxes, there are generalized coordinate transformations that induce, as gauge symmetries of DFT, the requisite O(d,d;ℤ) monodromy transformations. Finally we review recent results on the α^′ extension of DFT which, reduced to the half‐dimensional subspace, yields intriguing modifications of the basic structures of generalized geometry.     

Locally Stable Grothendieck Categories: Applications

We introduce for any Grothendieck category the notion of stable localizing subcategory, as a localizing subcategory that can be written as an intersection of localizing subcategories defined by indecomposable injectives. A Grothendieck category in which every localizing subcategory is stable is called a locally stable category. As a main result we give a characterization of these categories in terms of the local stability of a localizing subcategory and its quotient category. The locally coirreducible categories (in particular, the categories with Gabriel dimension) and the locally noetherian categories are examples of locally stable categories. We also present some applications to the category of modules over a left fully bounded noetherian ring, to the category of comodules over a coalgebra and to the category of modules over graded rings.     

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...     

Universality behaviour for polarity formation in channel-type inclusion compounds

A statistical investigation based on a Markov chain theory of polarity formation applied to channel-type inclusion compounds loaded with both dipolar A–π–D and non-polar N–π–N (N: A or D) guests is presented. The key parameters effecting polarity formation are identified and their effects are explored. A number of paradoxes are set out and an attempt to explain the mechanisms behind them is made: dependence of macroscopic polarity on orientational selectivity induced by intermolecular interactions, tuning of polarity through (i) the concentration of non-polar guest and (ii) growth temperature. An erratum to this article can be found at     

Global Dynamics of a Novel Delayed Logistic Equation Arising from Cell Biology

The delayed logistic equation (also known as Hutchinson’s equation or Wright’s equation) was originally introduced to explain oscillatory phenomena in ecological dynamics. While it motivated the development of a large number of mathematical tools in the study of nonlinear delay differential equations, it also received criticism from modellers because of the lack of a mechanistic biological derivation and interpretation. Here, we propose a new delayed logistic equation, which has clear biological underpinning coming from cell population modelling. This nonlinear differential equation includes terms with discrete and distributed delays. The global dynamics is completely described, and it is proven that all feasible non-trivial solutions converge to the positive equilibrium. The main tools of the proof rely on persistence theory, comparison principles and an $$L^2$$-perturbation technique. Using local invariant manifolds, a unique heteroclinic orbit is constructed that connects the unstable zero and the stable positive equilibrium, and we show that these three complete orbits constitute the global attractor of the system. Despite global attractivity, the dynamics is not trivial as we can observe long-lasting transient oscillatory patterns of various shapes. We also discuss the biological implications of these findings and their relations to other logistic-type models of growth with delays.     

Bis(3‐phenyl‐1,2,4‐thia­diazole‐5‐thiol­ato)mercury(II)

The title compound, [Hg(C₈H₅N₂S₂)₂], has crystallographic C₂ symmetry. The Hg—S distance is 2.353 (2) Å and the coordination geometry is linear, with an S—Hg—S angle of 179.77 (18)°. The exocyclic C—S single‐bond distance is 1.749 (6) Å, and intra­molecular Hg⋯N distances of 2.857 (4) Å exist, as well as secondary Hg⋯C and S⋯S contacts.     

Localization on certain Grothendieck categories

Using categorical techniques we obtain some results on localization and colocalization theory in Grothendieck categories with a set of small projective generators. In particular, we give a sufficient condition for such category to be semiartinian. For semiartinian Grothendieck categories where every simple object has a projective cover, we obtain that every localizing subcategory is a TTF-class. In addition, some applications to semiperfect categories are obtained.