Decomposition of silane on solid P4O10

Silane undergoes thermal decomposition on the surface of “phosphorus pentoxide” ( P₄O₁₀) into its elements around 200–400°C. The hydrogen formed partially reduces the P₄O₁₀ forming lower oxides of phosphorus and water. Elemental silicon is precipitated as reddish-brown solid, which is separated by dissolving out the phosphorus oxides. Silica and disiloxane are not formed in the reaction.     

Synthesis of erythrinin A,a naturally occurring pyranoisoflavone

Erythrinin A ($\text{10}$) has been synthesised by the oxidative rearrangement of dihydropyranochalcone $\text{1}$ with thallium(III) nitrate (TTN) in trimethyl orthoformate (TMOF) to the dimethyl acetal $\text{2}$, followed by cyclisation to $\text{3}$, demethylation to $\text{6}$ and dehydrogenation. Compound $\text{10}$ could also be obtained from chalcone $\text{4}$ on similar rearrangement followed by cyclisation, demethoxymethylation and dehydrogenation. In another route, chalcone $\text{7}$ was oxidatively rearranged with TTN in TMOF, to $\text{8}$ which on treatment with HCl yielded $\text{10}$.     

Biosynthesis of zinc oxide nanoparticles using Euphorbia milii leaf constituents: Characterization and improved photocatalytic degradation of methylene blue dye under natural sunlight

A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m²/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm³/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm^?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications.     

Ionic liquid mediated synthesis and in vitro mechanistic exploration of polycyclic cage-like heterocyclic hybrid

A three-component, [3 + 2]-cycloaddition/annulation domino protocol is described for the synthesis in excellent yield of a polycyclic cage-like heterocyclic hybrid (PCHH) that comprises various advantaged structural units viz., α,β-unsaturated ketone moiety, 4-pyridinone and pyrroloisoquinoline in a cage-like framework. The antitumor activity of PCHH on human breast (MCF7), colon (HCT116), cervical (JURKAT) and lung (NCI-H460) malignant cell lines inhibited the propagation of all cell lines. This hybrid molecule displayed increased broad-spectrum anticancer activity with higher doses of PCHH. Furthermore, the compound induced 45.21% of early apoptosis and 46.32% of late apoptosis in the Jurkat cancer cell line. Cell cycle analysis showed that this cage-like compound caused cell cycle arrest of Jurkat cells at the S phase and sub G0/G1 phase. Additionally, it led to increased DNA fragmentation and mitochondrial membrane permeabilization through activation of caspase-3 enzyme. Present investigation demonstrates the specific cytotoxic activity of the cage-like compound and the induction of apoptosis through the intrinsic pathway of Jurkat cells.     

Nanocomposite Hydrogel of Pd@ZIF-8 and Laponite®: Size-Selective Hydrogenation Catalyst under Mild Conditions

The composite hydrogel of a nanoscale metal–organic framework (NMOF) and nanoclay has emerged as a new soft-material with advanced properties and applications. Herein, we report a facile synthesis of a hydrogel nanocomposite by charge-assisted self-assembly of Pd@ZIF-8 nanoparticles with Laponite^® nanoclay which coat the surface of Pd@ZIF-8 nanoparticles. Such surface coating significantly enhanced the thermal stability of the ZIF-8 compared to the pristine framework. Further, the Pd@ZIF-8+LP hydrogel nanocomposite shows better size-selective catalytic hydrogenation of olefins than Pd@ZIF-8 nanoparticles based on selective diffusion of the substrate.     

A PVC-based pentathia-15-crown-5 membrane potentiometric sensor for mercury(II)

Poly(vinyl chloride) (PVC)-based membrane of pentathia-15-crown-5 exhibits good potentiometric response for Hg²⁺ over a wide concentration range (2.51 × 10⁻⁵ to 1.00 × 10⁻¹ mol dm⁻³) with a slope of 32.1 mV per decade of Hg²⁺ concentration. The response time of the sensor is as fast as 20 s. The electrode has been used for a period of six weeks and exhibits fairly good discriminating ability towards Hg²⁺ in comparison to alkali, alkaline and some heavy metal ions. The electrode can be used in the pH range from 2.7 to 5.0.     

Amidine- and Amidoxime-Substituted Heterocycles: Synthesis,Antiproliferative Evaluations and DNA Binding

The novel 1,2,3-triazolyl-appended N- and O-heterocycles containing amidine 4–11 and amidoxime 12–22 moiety were prepared and evaluated for their antiproliferative activities in vitro. Among the series of amidine-substituted heterocycles, aromatic diamidine 5 and coumarine amidine 11 had the most potent growth-inhibitory effect on cervical carcinoma (HeLa), hepatocellular carcinoma (HepG2) and colorectal adenocarcinoma (SW620), with IC₅₀ values in the nM range. Although compound 5 was toxic to non-tumor HFF cells, compound 11 showed certain selectivity. From the amidoxime series, quinoline amidoximes 18 and 20 showed antiproliferative effects on lung adenocarcinoma (A549), HeLa and SW620 cells emphasizing compound 20 that exhibited no cytostatic effect on normal HFF fibroblasts. Results of CD titrations and thermal melting experiments indicated that compounds 5 and 10 most likely bind inside the minor groove of AT-DNA and intercalate into AU-RNA. Compounds 6, 9 and 11 bind to AT-DNA with mixed binding mode, most probably minor groove binding accompanied with aggregate binding along the DNA backbone.     

Disposition Kinetics of Amitraz in Lactating Does

Amitraz, a member of the formamidine pesticide family, commonly used for ectoparasite control, is applied as a dip or low-pressure hand spray to cattle and swine, and the neck collar on dogs. Data on amitraz were generated mainly on laboratory animals, hens, dogs, and baboons. The data on the toxicity and disposition of amitraz in animals and its residues in the milk are inadequate. Therefore, the present study was intended to analyze the disposition kinetics of amitraz and its pattern of elimination in the milk of lactating does after a single dermal application at a concentration of 0.25%. Blood at predetermined time intervals and milk twice daily were collected for eight days post application. The drug concentration was assayed by high-performance liquid chromatography (HPLC). Amitraz was detected in whole blood as early as 0.5 h, which attained a peak concentration at 12 ± 5 h, followed by a steady decline; however, detection persisted until 168 h. Amitraz was present in the blood at its 50% C_max even after 48 h, and was still detectable after 7 days. The disposition after a single dermal application was best described non-compartmentally. The mean terminal half-life (t_1/2), mean residence time (MRT), and area under the curve (AUC_0–t) were 111 ± 31 h, 168 ± 39 h, and 539 ± 211 µg/mL/h, respectively. The apparent volume of distribution (Vd_area) was 92 ± 36 mL/g with an observed clearance (Cl) of 0.57 ± 0.33 mL/kg/h. Thus, the drug was well absorbed, widely distributed and slowly eliminated from the animal body. Amitraz achieved milk concentration approximating 0.2 per cent of the total dose after a single exposure and the steady-state elimination of amitraz in milk above the recommended maximum residue limit (MRL) of 0.01 mg/kg can act as a source of public health concern when applied on lactating animals.     

Modulation of the PGE2-Mediated Pathway in the Eclosion Blocking Effect of Flumethrin and Terpenoid Subfraction Isolated from Artemesia nilagirica in Rhipicephalus annulatus

Prostaglandins are a group of important cell-signaling molecules involved in the regulation of ovarian maturation, oocyte development, egg laying and associated behaviors in invertebrates. However, the presence of prostaglandin E₂ (PGE₂), the key enzymes for PGE₂ biosynthesis and its interference by drugs were not investigated previously in the ovary of ticks. The present study was undertaken to assess the modulation of the PGE₂-mediated pathway in the eclosion blocking effect of flumethrin and terpenoid subfraction isolated from Artemisia nilagirica in Rhipicephalus annulatus ticks. The acaricidal activities and chemical profiling of the terpenoid subfraction were performed. The localization of the cyclooxygenase1 (COX1) and prostaglandin E synthase (PGES) enzymes and the quantification of PGE₂ in the ovaries of the ticks treated with methanol (control), flumethrin and terpenoid subfraction were also undertaken. In addition, the vitellogenin concentration in hemolymph was also assayed. Both flumethrin and the terpenoid subfraction of A. nilagirica elicited a concentration-dependent inhibition of fecundity and blocking of hatching of the eggs. The COX1 could not be detected in the ovaries of treated and control ticks, while there was no significant difference observed in the concentration of vitellogenin (Vg) in them. The presence of PGES in the oocytes of control ticks was confirmed while the immunoreactivities against PGES were absent in the vitellogenic oocytes of ticks treated with flumethrin and terpenoid subfraction. The levels of PGE₂ were below the detection limit in the ovaries of the flumethrin-treated ticks, while it was significantly lower in the ovaries of the terpenoid subfraction-treated ticks. Hence, the prostaglandin E synthase and PGE₂ were identified as very important mediators for the signaling pathway for ovarian maturation and oviposition in ticks. In addition, the key enzyme for prostaglandin biosynthesis, PGES and the receptors for PGE₂ can be exploited as potential drug targets for tick control. The detection of PGES by immunohistochemistry and quantification of PGE₂ by LC-MSMS can be employed as valuable tools for screening newer compounds for their eclosion blocking acaricidal effects.