Dilatonic black holes in gravity’s rainbow with a nonlinear source: the effects of thermal fluctuations

This paper is devoted to an investigation of nonlinearly charged dilatonic black holes in the context of gravity’s rainbow with two cases: (1) by considering the usual entropy, (2) in the presence of first order logarithmic correction of the entropy. First, exact black hole solutions of dilatonic Born–Infeld gravity with an energy dependent Liouville-type potential are obtained. Then, thermodynamic properties of the mentioned cases are studied, separately. It will be shown that although mass, entropy and the heat capacity are modified due to the presence of a first order correction, the temperature remains independent of it. Furthermore, it will be shown that divergences of the heat capacity, hence phase transition points are also independent of a first order correction, whereas the stability conditions are highly sensitive to variation of the correction parameter. Except for the effects of a first order correction, we will also present a limit on the values of the dilatonic parameter and show that it is possible to recognize AdS and dS thermodynamical behaviors for two specific branches of the dilatonic parameter. In addition, the effects of nonlinear electromagnetic field and energy functions on the thermodynamical behavior of the solutions will be highlighted and dependency of critical behavior, on these generalizations will be investigated.     

Amine‐Assisted Syntheses of Carbonate‐Free and Highly Crystalline Nitrate‐Containing Zn‐Al Layered Double Hydroxides

Zn‐Al layered double hydroxides (LDHs), with nitrate as the charge balancing anion in the interlayer space, were synthesized by precipitation from homogeneous solution containing different amines [e.g., hexamethylenetetraamine (HMTA), diethylenediamine (DEDA), trimethylamine (TMA) and dimethylamine (DMA)]. The applied method does not require nitrogen atmosphere. The solution pH and concentration of different amines were varied in order to identify the controlling parameters and whether nitrate or carbonate are the interlayer anion. Particularly, the addition of amines turns out to be an effective tool for the synthesis of nitrate containing Zn‐Al LDHs independent from the nitrogen atmosphere. The structure, textural, composition, and morphological properties were investigated using the powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA), FT‐IR spectroscopy, and scanning electron microscopy (SEM). The analyses showed that the samples had high crystallinity and purity. The NO₃‐ZnAl LDHs samples show that LDH sheets are predominantly smooth textured and the thickness of LDH sheets are found to be around 23 nm. The results also indicate that this method successfully produces a NO₃^– form Zn‐Al LDH that is almost identical to the one synthesized by conventional methods.     

Evaluation of microstructural features of a new polymeric organic stationary phase grafted on silica surface: A paradigm of characterization of HPLC-stationary phases by a combination of suspension-state H NMR and solid-state C-CP/MAS-NMR

Silica-supported poly(octadecylacrylate) (Sil-ODA_n), polymeric octadecylsilyl silica (polymeric ODS), and monomeric octadecylsilyl silica (monomeric ODS) were studied by a combination of suspension-state ¹H NMR and solid-state ¹³C CP/MAS-NMR to probe the mechanisms underlying their functions as stationary phases for RP-HPLC. Sil-ODA_n, with a strong temperature dependent separation behaviour showed correspondent temperature dependent manifestations in both suspension-state ¹H NMR and solid-state ¹³C CP/MAS-NMR experiments. With a gradual increase in temperature, intensity of proton signals (¹H NMR) of octadecyl moieties (mainly methylene groups) rose dramatically. This dramatic rise was at the same temperature of an endothermic peak detectable in its DSC thermogram indicating a relatively complete solid to liquid phase transition. In addition temperature dependencies of the ratio of trans to gauche conformed well to temperature dependencies of the separation factor between naphthacene and triphenylene (as a simple indicator of shape selectivity). Therefore NMR spectra of Sil-ODA_n were used as a reference for ascertaining percentage of octadecyl moieties of liquid type mobility in the two other stationary phases. Using this method we determined percentage of liquid phase in polymeric ODS and monomeric ODS at various temperatures. We suggest a combination of suspension-state ¹H NMR and solid-state ¹³C CP/MAS-NMR for structure-dynamic characterization of various kinds of hydrocarbon chains grafted onto the silica particles.     

Overview on the recently developed thiazolyl heterocycles as useful therapeutic agents

Thiazoles are important heterocyclic compounds which have many biological activities and different applications such as useful ligands, in optical sensors, etc. A literature survey shows that there are different routes to thiazoles. One of the most frequently used synthetic approaches consists of a reaction between α-halocarbonyl compounds with a CSNH₂ moiety. In this mini-review we have classified the contents based on the reagent or material providing the sulfur atom of the thiazole ring. Also, among many articles which have been devoted to thiazole syntheses here we presented some synthetic approaches published from 2012 to 2014.     

Carbon-based magnetic nanocomposites in solid phase dispersion for the preconcentration some of lanthanides, followed by their quantitation via ICP-OES

We report on a method for the extraction of the lanthanide ions La(III), Sm(III), Nd(III) and Pr(III) using a carbon-ferrite magnetic nanocomposite as a new adsorbent, and their determination via flow injection ICP-OES. The lanthanide ions were converted into their complexes with 4-(2-pyridylazo)resorcinol, and these were adsorbed onto the nanocomposite. Fractional factorial design and central composite design were applied to optimize the extraction efficiencies to result in preconcentration factors in the range of 141–246. Linear calibration plots were obtained, the limits of detection (at S/N?=?3) are between 0.5 and 10 μg?L^?1, and the intra-day precisions (n?=?3) range from 3.1 to 12.8 %. The method was successfully applied to a certified reference material.

Self-doped polyaniline as new polyaniline substitute for solid-phase microextraction

This work is a first study on extraction efficiency and thermal stability of nano-structured self-doped polyaniline (SPAN) as a coating of solid-phase microextraction (SPME) fibers. SPAN-based fibers were prepared using electrochemical deposition on platinum wires. The particle sizes of prepared nano-structure were in the range of 50–100 nm. Extraction properties of the fiber to 1,4-dioxane were examined using headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-flame ionization detection (GC-FID). The results have proved higher thermal stability of the proposed fiber compared to common PANI fiber. The SPAN coating was proved to be very stable at relatively high temperatures (up to 350 °C) with high extraction capacity and long lifespan (more than 50 times). Therefore, it can be a good substitute of polyaniline (PANI) as a SPME coating. The extraction procedure was optimized by selecting the appropriate extraction parameters including extraction time, extraction temperature, salt concentration, stirring rate and headspace volume. Calibration graph was linear in the concentration range of 1–100 ng mL⁻¹ (R² > 0.993) with detection limit of 0.1 ng mL⁻¹. Single fiber and fiber-to-fiber repeatability were lower than 6.0% and 10.4%, respectively. Different water samples were analyzed as real samples and good recoveries (98–120%) were obtained.     

Synthesis and structure of mono- and di-nuclear complexes of ortho-palladated derived from phosphorus ylides

The phosphorus ylides Ph₃PCHC(O)C₆H₄R (R = 4-Me 1a, 4-Br 1b) react with PdCl₂ in equimolar ratios to give the C,C-orthopalladated [Pd{CHP(C₆H₄)Ph₂CO-C₆H₄-R)}(μ-Cl)]₂ (R = 4-Me 2a, 4-Br 2b) which react with NaClO₄/dppe, NaClO₄/dppm, py and PPh₃ to give the mononuclear derivatives [Pd{CH{P(C₆H₄)Ph₂}COC₆H₄-R}(dppe-P,P′)[(ClO₄) (R = 4-Me 3a, 4-Br 3b), [Pd{CH{P(C₆H₄)Ph₂}COC₆H₄-R}(dppm-P,P′)[(ClO₄ ( (R = 4-Me 4a, 4-Br 4b), [Pd{CH{P(C₆H₄)Ph₂}COC₆H₄-R}Cl(L)] (L = py, R = 4-Me 5a, 4-Br 5b, L = PPh₃, R = 4-Me 6a, 4-Br 6b). The C, C-metalated chelate are demonstrated by an X-ray diffraction study of 3a and 4a. Characterization of the obtained compounds was also performed by elemental analysis, IR, ¹H, ³¹P, and ¹³C NMR.