110°C thermoluminescence glow peak of quartz — A brief review

The 110°C glow peak of quartz, though unstable at room temperature, has worked wonderfully in archaeology and retrospective dosimetry due to its pre-dose sensitization property. Various aspects of the peak, like its nature, defect centres involved, the impact of different stimuli and its application have been extensively studied. The main aims of this review are to (i) summarize briefly the work carried out on the various facets of this TL glow peak during the last four decades and (ii) identify the areas which need further attention in order to have a better understanding of the luminescence characteristics of this TL peak.      

Simple and efficient one‐pot synthesis of 3,4‐dihydro‐2‐pyridones via solid‐supported Bi(III)nitrate catalyzed double michael addition‐azaannulation

4‐Aryl‐5‐carboethoxy‐6‐methyl‐2,3‐dihydro‐2‐pyridones were obtained, in high yield, by heating ternary mixtures of appropriate aldehydes, ethylacetoacetate and compounds possessing NH₂‐C=X functionality, in presence of immobilized Bi(III)nitrate and co‐catalyst Zn(II)chloride, under solventless conditions. The reaction proceeds smoothly at 140±5°C and seems to involve double Michael addition‐azaannulation.     

Quantitative determination of macroelement and microelement content of fresh and processed bamboo shoots by wavelength dispersive X-ray fluorescence spectrometry

Bamboo shoots are considered as healthy and nutritional food as they supply proteins, dietary fiber, phenols, phytosterols, vitamins, and minerals in considerable quantities and capture a novel place in the spectrum of plant foods. Besides nutrients and bioactive compounds, shoots also contain antinutrient (cyanogen) that needs to be removed by adequate processing prior to consumption. This study was undertaken to investigate the effects of fermentation, brine preservation, and boiling on levels of mineral elements in shoots of Dendrocalamus hamiltonii using wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry. WD-XRF spectrometry is a method that causes the least destruction to the raw plant material as no harsh chemicals are used and gives the most accurate results. Fermentation process resulted in significant increase in the levels of Rb (9%), S (11%), Mg (12%), Zn (46%), Ca (56%), and Fe (87%); however, Na (18.79 g/100 g, dry weight), Cl (24.73 g/100 g, dry weight), and Br (20.0 mg/100 g, dry weight) content increased drastically after brine preservation. Boiling increased the levels of Fe by 139% but did not affect the Rb (20.0 mg/100 g, dry weight) and Zn content (10.2 mg/100 g, dry weight) of the shoots. In general, fermentation, which led to the lowest loss of mineral elements, appears the best method in enhancement and retention of the mineral content in bamboo shoots and holds the prospect at industrial and society levels.     

Simultaneous quantification of five marker compounds of Betula utilis stem bark using a validated high-performance thin-layer chromatography method

A sensitive, selective and robust densitometric high-performance thin-layer chromatographic method was developed and validated for five marker compounds, namely betulin, lupeol, oleanolic acid, 3-acetyloleanolic acid and β-sitosterol, known for their various therapeutic activities. The marker compounds have been isolated from the stem bark of Betula utilis, well characterized by the spectral analysis, and their simultaneous quantitative determination carried out by high-performance thin-layer chromatography (HPTLC) method. The resolution of marker compounds was carried out on silica-gel 60 plates, using n-hexane:ethyl acetate (8:2 v/v) as the mobile phase. The HPTLC densitometry was performed at 500-nm wavelength after the post chromatographic derivatization with ceric ammonium sulfate reagent. The optimized method provided good linear relation (r>0.9960) for all the investigated analytes. The method is simple, and reproducible, which may be applied for quantitative analysis of the above-mentioned marker compounds.     

Minimum distance estimation in linear regression with unknown error distributions

This paper discusses minimum distance (m.d.) estimators of the paramter vector in the multiple linear regression model when the distributions of errors are unknown. These estimators are defined in terms of L₂-distances involving certain weighted empirical processes. Their finite sample properties and asymptotic behavior under heteroscedastic, symmetric and asymmetric errors are discussed. Some robustness properties of these estimators are also studied.     

Integrals involving Fox’sH-function

We evaluate four integrals involving Fox’sH-functions and a general class of polynomialsS _n ^m [x], introduced earlier by Srivastava.     

Odoriferous Cyclic Ethers via Co‐Halogenation Reaction: Facile Preparation of Nerol Oxide,Florol®, Florol® Methyl Ether,and Pityol® Methyl Ether

A series of odoriferous cyclic ethers, including nerol oxide ( 1 ), Florol^® ( 2 ), Florol methyl ether ( 3 ), and Pityol^® methyl ether ( 4b ), were prepared by a versatile synthetic protocol based on co‐halogenation with 1,3‐dibromo‐5,5‐dimethylhydantoin (= 1,3‐dibromo‐5,5‐dimethylimidazolidine‐2,4‐dione; DDH) as the key step. The methodology provides a facile access to important perfumery molecules from abundantly available monoterpene alcohols.     

A single pot synthesis of new dimeric 2‐phenyl‐10,3a‐dihydro‐1,3,4‐oxadiazolino[3,2‐a]quinazolin‐6‐ols

One pot synthesis of new unsymmetrical dimeric 2‐phenyl‐10,3a‐dihydro‐1,3,4‐oxadiazolino[3,2‐a]‐quinazolin‐6‐ols from 2‐amino‐5‐phenyloxadiazole and salicylaldehydes, in solid phase, using Hg (II)‐A1₂O₃ catalyst, is described. The reaction is temperature sensitive, convenient, efficient and environmentally friendly.     

Synergistic Effects of Co and Fe on the Oxygen Evolution Reaction Activity of LaCoxFe1−xO3

In a combined experimental and theoretical study we assess the role of Co incorporation on the OER activity of LaCo_xFe_1−xO₃. Phase pure perovskites were synthesized up to in 0.025/0.050 steps. HAADF STEM and EDX analysis points towards FeO₂-terminated (001)-facets in LaFeO₃, in accordance with the stability diagram obtained from density functional theory calculations with a Hubbard U term (DFT+U). Linear sweep voltammetry conducted in a rotating disk electrode setup shows a reduction of the OER overpotential and a nonmonotonic trend with x, with double layer capacitance measurements indicating an intrinsic nature of activity. This is supported by DFT+U results that show reduced overpotentials for both Fe and Co reaction sites with the latter reaching values of 0.32–0.40 V, ∼0.3 V lower than for Fe. This correlates with a stronger reduction of the binding energy difference of the *O and *OH intermediates towards an optimum value of 1.6 eV for , the OH deprotonation being the potential limiting step in most cases. Significant variations of the magnetic moments of both surface and subsurface Co and Fe during OER demonstrate that the beneficial effect is a result of a concerted action involving many surrounding ions, which extends the concept of the active site.     

Full wave analysis of non-radiative dielectric waveguide modulator for the determination of electrical equivalent circuit

This paper reports the determination of electrical equivalent circuit of ON/OFF modulator in non-radiative dielectric (NRD) guide configurations at Ka-band. Schottky barrier mixer diode is used to realize this modulator and its characteristics are determined experimentally using vector network analyzer. Full wave FEM simulator HFSS is used to determine an equivalent circuit for the mounted diode and modulator in ON and OFF states. This equivalent circuit is used to qualitatively explain the experimental characteristics of modulator.