Magnetic Nanoparticle-Supported Cu–NHC Complex as an Efficient and Recoverable Catalyst for Nitrile Hydration

Magnetic nanoparticles supported N-heterocyclic carbene–Cu complex was prepared and authenticated by FT-IR, SEM, EDX, VSM, powder-XRD. The catalytic activity of these magnetically retrievable NPs was investigated for hydration of nitriles as the simplest route for the synthesis of amides in an atom-economical manner. A wide range of nitriles containing various functional groups such as olefin, aldehyde, nitro, carboxylic acid was examined in this transformation to generate their corresponding amides in the aqueous medium. The immobilized catalyst was easily recovered using an external magnet and reused for six times without significant loss of its catalytic activity.

Graphical Abstract

Open image in new window

     

Encapsulation of Plant Biocontrol Bacteria with Alginate as a Main Polymer Material

One of the most favored trends in modern agriculture is biological control. However, many reports show that survival of biocontrol bacteria is poor in host plants. Providing biocontrol agents with protection by encapsulation within external coatings has therefore become a popular idea. Various techniques, including extrusion, spray drying, and emulsion, have been introduced for encapsulation of biocontrol bacteria. One commonly used biopolymer for this type of microencapsulation is alginate, a biopolymer extracted from seaweed. Recent progress has resulted in the production of alginate-based microcapsules that meet key bacterial encapsulation requirements, including biocompatibility, biodegradability, and support of long-term survival and function. However, more studies are needed regarding the effect of encapsulation on protective bacteria and their targeted release in organic crop production systems. Most importantly, the efficacy of alginate use for the encapsulation of biocontrol bacteria in pest and disease management requires further verification. Achieving a new formulation based on biodegradable polymers can have significant effects on increasing the quantity and quality of agricultural products.     

Partial compensation signal-level-based up-link power control toextend terminal battery duration

Power control (PC) techniques have been studied for years with the aim of reducing interference and allowing efficient battery energy management. Among PC algorithms, those based on the signal-level (not on cochannel interference) show good characteristics in terms of network stability and provide optimum downlink performance when a half-compensation scheme is used instead of a full-compensation algorithm. This work is concerned with partial (including the full and half cases) compensation signal-level-based PC algorithms and their impact on battery duration of mobile terminals, i.e., the uplink is investigated. A time division multiple access (TDMA)-based cellular system is considered. The effect of a slow PC, i.e., following only slow channel fluctuations, on the average transmitted power of mobile terminals is evaluated through a completely analytical model; both ideal and nonideal PC are considered. Starting from suitable requirements on radio coverage, we show that a half-compensation PC scheme is often a good choice for extending terminal battery life (thus, also reducing health risks)     

Nanofibrous poly(ethylene oxide)‐based structures incorporated with multi‐walled carbon nanotube and graphene oxide as all‐solid‐state electrolytes for lithium ion batteries

Nanofibrous solid polymer electrolytes were prepared using the electrospinning method. These nanofibres were constructed from poly(ethylene oxide), lithium perchlorate and ethylene carbonate, which were incorporated with multi‐walled carbon nanotube (MWCNT) and graphene oxide (GO). The morphological properties of the as‐prepared electrolytes and the interaction between the components of the composites were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. X‐ray spectra and differential scanning calorimetry indicated an increase in amorphous regions of the nanofibrous electrolytes on addition of the fillers. However, the crystalline regions were increased on incorporation of fillers into polymeric film electrolytes. The conductivity values of the nanofibrous electrolytes reached 0.048 and 0.057 mS cm^?1 when 0.35 wt% MWCNT and 0.21 wt % GO were introduced into the nanofibrous structures, respectively. The capacity and cycling stability of the nanofibrous electrolytes were improved by incorporation of MWCNT filler. Furthermore, stress and elongation modulus were improved at low MWCNT and GO filler contents. Results revealed that the nanofibrous structures could be promising candidates as solvent‐free electrolytes applicable in lithium ion batteries. © 2019 Society of Chemical Industry     

Novel bilayer electrospun poly(caprolactone)/ silk fibroin/ strontium carbonate fibrous nanocomposite membrane for guided bone regeneration

In this study, a thin layer with a thickness of about 120 μm of poly(caprolactone) (PCL) was fabricated by electrospinning method. Then, a fibrous nanocomposite composed of PCL/silk fibroin/strontium carbonate (PCL/SF/SrCO₃) was electrospun on the prepared layer. Then, they were characterized. The mechanical properties, water uptake, degradation rate, wettability, porosity, and bioactivity of the electrospun membrane were scrutinized in vitro. Cytotoxicity of the samples was assessed by using osteoblast-like cells (SAOS-2) and L929 fibroblasts. Moreover, the cell adhesion, alkaline phosphatase (ALP) activity, and calcium deposition through alizarin red staining were conducted. Results revealed that the bilayer structure doubled the optimum mechanical properties and the addition of SrCO₃ up to 15%–20% increased ALP activity, calcium deposition, and bioactivity. According to the results, the nanofibrous bilayer membrane containing 20 wt% SrCO₃, 20 wt% SF, and 60 wt% PCL was chosen as the optimum sample. Therefore, this membrane could be applied in guided bone regeneration (GBR).     

Photoluminescence and UV photosensitivity of few-layered MoS2 nanosheets synthesized under different hydrothermal growth times

Journal of Materials Science - MoS2 flower-like microspheres composed of 2D nanosheets were prepared using the simple and cost-effective method of hydrothermal. The effects of hydrothermal process...