A note on duality of generalized equilibrium problem

The main aim of this note is to extend the dual (in the form of an optimization problem) given for equilibrium problem by Martinez-Legaz and Sosa (in J Glob Optim 35:311–319, 2006) for a generalized equilibrium problem in finite dimensional setting and to establish its equivalence with the dual derived by Bigi et al. (in J Math Anal Appl 342:17–26, 2008) (in the form of inclusion conditions) under a mild condition.     

Carbon-carbon bond forming reactions via Pd-catalyzed detellurative homocoupling of diorganyl tellurides

A simple and highly efficient method for the constructions of Csp-Csp, Csp²-Csp² and Csp³-Csp³ bonds is reported. The symmetrical diaryl tellurides undergo detellurative homocouplings to afford symmetrical biaryl products. The reactions are carried out at ambient temperature using PdCl₂ as a catalyst in the presence of Ag₂O and Na₂CO₃. Similarly, the detellurative homocouplings of dibenzyl telluride and bis(phenylethynyl)telluride give bibenzyl and the conjugated diyne, respectively.     

Cyanuric chloride catalyzed metal-free mild protocol for the synthesis of highly functionalized tetrahydropyridines

An environmentally benign, facile and elegant synthetic approach for the convenient access of a series of diverse 2,6-diaryl-tetrahydropyridine-3-carboxylates via a one-pot, pseudo five-component condensation of ethyl acetoacetate, anilines and aromatic aldehydes under mild reaction conditions has been described. This domino strategy allows rapid cyclization in the presence of 10 mol% of cyanuric chloride as a source of hydrochloric acid to afford the desired target skeletons in excellent yields. The present protocol offers prominent advantages of simple operational procedure, metal-free organocatalyst, practically robust and extensive substrate scope.     

Cellulase Production by Pink Pigmented Facultative Methylotrophic Strains (PPFMs)

Pink pigmented facultative methylotrophs (PPFM) isolated from water samples of Cooum and Adyar rivers in Chennai and soil samples of forests located in various districts of Tamil Nadu, India were screened for cellulase production using carboxymethylcellulose agar (CMC agar) medium. The strains showed wide variations in the production of clearing zones around the colonies on CMC agar medium flooded with Congo red. CMCase and filter paper assays were used to quantitatively measure the cellulase activity of 13 PPFM strains. Among the strains, Methylobacterium gregans, MNW 60, MHW 109, MSF 34, and MSF 40 showed cellulolytic activity ranging from 0.73 to 1.16 U mL⁻¹ with wide temperature (35–65°C) and pH (5 to 8) tolerance. SDS-PAGE analysis of the crude enzyme of PPFM strain MNW 60 exhibited several protein bands, and zymogram analysis revealed two dimeric cellulase bands with molecular mass of ~92 and 42 kDa. Scanning electron microscopic studies revealed significant morphological differences between the cells grown in normal and CMC amended medium. The strain MNW 60 was identified as Methylobacterium sp. based on biochemical, physiological, and morphological analyses, and the methylotrophic nature was authenticated by the presence of mxaF gene, encoding methanol dehydrogenase as a key indicator enzyme of methylotrophs, with 99% similarity to Methylobacterium lusitanum. With the 16S ribosomal RNA sequence showing 97% similarity to M. lusitanum strain MP2, this can be proposed as a novel taxon of the genus Methylobacterium. The study forms the first detailed report on the extracellular cellulase production by pink pigmented Methylobacterium sp., and it is expected that this might be the basis for further studies on cellulase production by PPFMs to explore the molecular mechanism, strain improvement, and large-scale cellulase production for its application.     

Cyclohexanol dehydrogenation over Cu-loaded TiO2 photocatalyst under solar illumination

Abstract  

The liquid-phase selective dehydrogenation of cyclohexanol has been investigated using two classes of catalyst containing either Cu₂O or CuO on TiO₂ under solar light in deaerated conditions at room temperature using acetonitrile medium in a batch reactor. The effect on dehydrogenation of three conditions, cyclohexanol concentration, copper loading on TiO₂, and amount of catalyst, were investigated. The maximum yield of cyclohexanone obtained was 40%. The catalysts were characterized by XRD, UV–DRS, TEM, SEM–EDAX, and XPS. It was found that 1% (w/w) Cu₂O/TiO₂ was 100% selective for photocatalytic dehydrogenation of cyclohexanol.     

Cordyceps militaris Fungus Extracts-Mediated Nanoemulsion for Improvement Antioxidant,Antimicrobial, and Anti-Inflammatory Activities

This study aimed to produce and optimize a Cordyceps militaris-based oil-in-water (O/W) nanoemulsion (NE) encapsulated in sea buckthorn oil (SBT) using an ultrasonication process. Herein, a nonionic surfactant (Tween 80) and chitosan cosurfactant were used as emulsifying agents. The Cordyceps nanoemulsion (COR-NE) was characterized using Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and field-emission transmission electron microscope (FE-TEM). The DLS analyses revealed that the NE droplets were 87.0 ± 2.1 nm in diameter, with a PDI value of 0.089 ± 0.023, and zeta potential of −26.20 ± 2. The small size, low PDI, and stable zeta potential highlighted the excellent stability of the NE. The NE was tested for stability under different temperature (4 °C, 25 °C, and 60 °C) and storage conditions for 3 months where 4 °C did not affect the stability. Finally, in vitro cytotoxicity and anti-inflammatory activity were assessed. The results suggested that the NE was not toxic to RAW 264.7 or HaCaT (human keratinocyte) cell lines at up to 100 µL/mL. Anti-inflammatory activity in liposaccharides (LPS)-induced RAW 264.7 cells was evident at 50 µg/mL and showed inhibition of NO production and downregulation of pro-inflammatory gene expression. Further, the NE exhibited good antioxidant (2.96 ± 0.10 mg/mL) activity and inhibited E. coli and S. aureus bacterial growth. Overall, the COR-NE had greater efficacy than the free extract and added significant value for future biomedical and cosmetics applications.     

Glycerol assisted eco-friendly strategy for the facile synthesis of 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ols) and 2-aryl-2,3-dihydroquinazolin-4(1H)-ones under catalyst-free conditions

Research on Chemical Intermediates - This article describes glycerol mediated eco-friendly approaches for the convenient access of structurally diverse...