Synthesis of 5-substituted 1H-tetrazoles and oxidation of sulfides by using boehmite nanoparticles/nickel-curcumin as a robust and extremely efficient green nanocatalyst

Nickel-anchored curcumin-functionalized boehmite nanoparticles (BNPs@Cur-Ni) as a robust and versatile nanocatalyst was synthesized and well-characterized by using Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray mapping, thermogravimetric analysis (TGA), differential thermal analysis (DTA), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The synthesis of 5-substituted 1H-tetrazoles and the oxidation of sulfides were conducted by BNPs@Cur-Ni with excellent turnover number (TON) and turnover frequency (TOF) outcomes. Also, the catalyst was reused for several sequential runs without Ni leaching or decreasing in reaction yield. Utilizing the curcumin and boehmite with a natural source as well as poly(ethylene glycol) (PEG) as a solvent in this simple protocol can be based on green chemistry rules.     

Pillar[5]arene‐Stabilized Silver Nanoclusters: Extraordinary Stability and Luminescence Enhancement Induced by Host–Guest Interactions

Herein, we report the synthesis of a new class of functional silver nanoclusters (AgNCs) capped with pillar[5]arene (P5)‐based host ligands. These NCs are readily prepared through direct synthesis or ligand exchange synthesis and are stable at room temperature for over 4 months. The pillar[5]arene‐stabilized NCs (Ag₂₉(LA‐P5)₁₂(TPP)₂) endorse reversible host–guest interactions with neutral alkylamines and cationic quaternary ammonium guests. This results in the formation of spherical assemblies with unparalleled changes in their optical properties including an astonishing circa 2000‐fold luminescence enhancement. This is the highest luminescence enhancement ratio reported so far for such atomically precise NCs. Our synthetic protocol paves the way for the preparation of a new generation of metal nanoclusters protected by macrocyclic ligands with molecular recognition and selectivity toward specific guests.     

Qubit entanglement driven by remote optical fields

We examine the entanglement between two qubits, supposed to be remotely located and driven by independent quantized optical fields. No interaction is allowed between the qubits, but their degree of entanglement changes as a function of time. We report a collapse and revival of entanglement that is similar to the collapse and revival of single-atom properties in cavity QED.     

Bar-shaped nanoparticles of iron(II) hydroxide

Formation of elongated nanoparticles was observed when was precipitated from solutions containing excess of Fe²⁺. The average diameter of the particles was 23 nm; the length to diameter ratio was up to 14. This shape was an unexpected phenomenon because bar- or needle-like nanoparticles have been earlier reported only for Fe(III)-based materials. Chemical analysis revealed Fe(OH)₂ nature of the obtained particles. In addition, this conclusion was verified with a new simple method for quantitative evaluation of the particle morphology. Application of this method to the mixed samples allowed to distinguish between the two different compounds and to attribute different morphologies to Fe(OH)₂ or Results indicate that bars are frequent shapes of nano-sized iron oxides/hydroxides.     

Transfer-printing of highly aligned DNA nanowires

We developed a simple method of reproducibly creating highly aligned DNA nanowires without any surface modifications or special equipment. Stretched DNA molecules initially present on the PDMS sheet were transferred onto another surface using transfer-printing (TP). Fluorescent microscopic and atomic force microscopic images revealed that many DNA molecules were highly aligned on surfaces after TP. Furthermore, it was also possible to realize the two-dimensional assembly of DNA nanowires by repeating TP.     

Oxorhenium(V) complexes with bidentate carbohydrazide Schiff bases: synthesis,characterization and DNA interaction studies

The respective coordination reactions of trans-[ReOCl₃(PPh₃)₂] with N-[(4-oxo-4H-chromen-3-yl)methylidene]thiophene-2-carbohydrazide (Hchrtc) and N-[1,3-benzothiazol-2-ylmethylidene]thiophene-2-carbohydrazide (Hbztc) afforded two novel oxorhenium(V) complexes, cis-[ReOCl₂(chrtc)(PPh₃)] (1) and cis-[ReOCl₂(bztc)(PPh₃)] (2). These metal compounds were elucidated spectroscopically and their solid-state structures determined by single-crystal X-ray diffraction. The redox properties of the metal complexes were probed using cyclic and square wave voltammetry. The DNA interaction capabilities of 1 and 2 were gauged via UV/Vis spectroscopy DNA titrations and gel electrophoresis studies. A correlation is identified between the DNA cleavage observations and the redox potentials of the metal complexes.     

Anti-Inflammatory Action and Mechanisms of Resveratrol

Resveratrol (3,4′,5-trihy- droxystilbene), a natural phytoalexin polyphenol, exhibits anti-oxidant, anti-inflammatory, and anti-carcinogenic properties. This phytoalexin is well-absorbed and rapidly and extensively metabolized in the body. Inflammation is an adaptive response, which could be triggered by various danger signals, such as invasion by microorganisms or tissue injury. In this review, the anti-inflammatory activity and the mechanism of resveratrol modulates the inflammatory response are examined. Multiple experimental studies that illustrate regulatory mechanisms and the immunomodulatory function of resveratrol both in vivo and in vitro. The data acquired from those studies are discussed.     

Numerical investigation and multi-criteria optimization of the thermal–hydraulic characteristics of turbulent flow in conical tubes fitted with twisted tape insert

Journal of Thermal Analysis and Calorimetry - The ever-growing interest in developing compact and more effective heat exchangers necessitates the investigation of combined passive solutions....     

Efficient Entrapment of Oxirane Ring Containing Compounds in Thermally Stable Poly(urea-formaldehyde) Polymer Shell Wall

This article aims to address the problems associated with the encapsulation of oxirane ring containing compounds in poly(urea-formaldehyde) (PUF) shell for application in self-healing composite systems. The main objectives were to produce non-agglomerated, stable microcapsules, and to control the pH drop during the encapsulation via oil-in-water emulsion polymerization. In the modified method; two stage additions of urea and formaldehyde monomers, core to shell ratio, weight percent and combination of two surfactants/emulsifiers were altered to produce the desired product. Analysis was done with optical microscope (OM), scanning electron microscopy (SEM), FTIR, particle size analyzer, and thermogravimetric analysis (TGA). The pH drop was confirmed by using a common epoxy resin, an epoxy functionalized polydimethylsiloxane (E-PDMS), and epoxidized palm oil (EPO) as cores. The modified oil-in-water emulsion polymerization of PUF was effective in preventing the pH drop during the encapsulation and a product stable for more than 3 months with less agglomeration was produced. The method produced microcapsules having diameters less than 100 μm at lower agitation rates. The modified method is only applicable to epoxy resin and not for compounds like amine hardeners. The use of stable microcapsules in self-healing coatings can lead towards cost reduction implied for repair and maintenance purposes.