Entrapment of pH Universal Indicator into Sol‐Gel Matrix

This study involves the behavior of universal indicator entrapped into the sol‐gel matrix. The encapsulation of universal indicator has been prepared by acid catalyzed sol‐gel reaction of tetraethylorthosilicate (TEOS) in the presence of universal indicator to produce transparent monolithic silica doping with universal indicator. The immobilized universal indicator pH‐indicator shows behavior similar to its solution counterpart. The UV/VIS spectra indicate that the universal indicator retains its structure during the sol‐gel reactions in terms of response to pH. The universal indicator can be regarded as uniformly distributed in the sol‐gel matrix. The use of SDS surfactant has positive effects on the immobilized universal indicator monolithic disk due to homogenizing the polymerizing system. This observation has been confirmed using polarized microscopy.     

THE PREPARATION AND SOME REACTIONS OF 3-THIETANONES

Abstract

3-Thietanones have been prepared by treating certain ketones with thionyl chloride or sulphur dichloride. In the case of ketones containing a tertiary alpha proton the initial product obtained on treatment with thionyl chloride is the sulphinyl chloride which then cyclises to the thietanone.     

Generation of Haploid Spermatids on Silk Fibroin-Alginate-Laminin-Based Porous 3D Scaffolds

In vitro production of sperm is a desirable idea for fertility preservation in azoospermic men and prepubertal boys suffering from cancer. In this study, a biocompatible porous scaffold based on a triad mixture of silk fibroin (SF), alginate (Alg), and laminin (LM) is developed to facilitate the differentiation of mouse spermatogonia stem cells (SSCs). Following SF extraction, the content is analyzed by SDS-PAGE and stable porous 3D scaffolds are successfully prepared by merely Alg, SF, and a combination of Alg-SF, or Alg-SF-LM through freeze-drying. Then, the biomimetic scaffolds are characterized regarding the structural and biological properties, water absorption capacity, biocompatibility, biodegradability, and mechanical behavior. Neonatal mice testicular cells are seeded on three-dimensional scaffolds and their differentiation efficiency is evaluated using real-time PCR, flow cytometry, immunohistochemistry. Blend matrices showed uniform porous microstructures with interconnected networks, which maintained long-term stability and mechanical properties better than homogenous structures. Molecular analysis of the cells after 21 days of culture showed that the expression of differentiation-related proteins in cells that are developed in composite scaffolds is significantly higher than in other groups. The application of a composite system can lead to the differentiation of SSCs, paving the way for a novel infertility treatment landscape in the future.     

Targeted Delivery of Anticancer Drug Loaded Charged PLGA Polymeric Nanoparticles Using Electrostatic Field

Pure positive electrostatic charges (PPECs) show suppressive effect on the proliferation and metabolism of invasive cancer cells without affecting normal tissues. PPECs are used for the delivery of drug-loaded polymeric nanoparticles (DLNs) capped with negatively charged poly(lactide-co-glycolide) (PLGA) and Poly(vinyl-alcohol) PVA into the tumor site of mouse models. The charged patch is installed on top of the skin in the mouse models' tumor region, and the controlled selective release of the drug is assayed by biochemical, radiological, and histological experiments on both tumorized models and normal rats' livers. It is found that DLNs synthesized by PLGA show great attraction to PPECs due to their stable negative charges, which would not degrade immediately in blood. The burst and drug release after less than 48h of this synthesized DLNs are 10% and 50%, respectively. These compounds can deliver the loaded-drug into the tumor site with the assistance of PPECs, and the targeted-retarded release will take place. Hence, local therapy can be achieved with much lower drug concentration (conventional chemotherapy [2 mg kg⁻¹] versus DLNs-based chemotherapy [0.75 mg kg⁻¹]) with negligible side effects in non-targeted organs. PPECs have many potential clinical applications for advanced-targeted chemotherapy with the lowest discernible side effects.     

Recent progresses on solution-processed silver nanowire based transparent conducting electrodes for organic solar cells

Organic photovoltaics (OPVs) are considered as a future alternative for conventional silicon based solar cells, owing to their low cost, ease of production and high-throughput. The transparent conducting electrode (TCE) is a fundamental component of OPVs. Traditionally, indium tin oxide (ITO) has been mainly utilized as a TCE in OPV applications due to its relatively high transparency and low sheet resistance. However, increasing demand for the optoelectronic devices has led to large fluctuations in ITO prices in the past decade and ITO is known to account more than 50% of the total cost of OPV devices. Thus, it is believed that development of solution-processable alternative materials is of great importance in reducing the cost of OPVs. Numerous materials, including silver nanowires, carbon nanotubes, graphene and conducting polymers, have been offered as replacements for ITO. This article reviews recent progress on fabrication of TCE via solution based coating techniques of silver nanowires (Ag NWs). In addition, performance of the Ag NWs based TCE in OPVs is summarized. Finally, we explore the future outlook for Ag NWs based TCE at the end of the review.     

Electropolymerization of Mefenamic Acid on Copper and Copper Based Alloy as a New Strategy to Control the Release of Copper Ions from Copper Containing Devices

Poly-2-(2,3-dimethylanilino) benzoic acid (PMF) coatings on copper and brass alloy were synthesized by electrochemical oxidation of 2-(2,3-dimethylanilino) benzoic acid in the presence of oxalic acid as the reaction medium. Electrodeposition was carried out using the cyclic voltammetry technique using a silver/silver-chloride standard electrode, with a scan rate of 600 mV min^–1. Smooth and well adhered PMF coatings were electrosynthesized during sequential scanning of the potential in the range–500 mV to 1400 mV on copper and brass alloy. The electrodeposited coatings were characterized by recording the oxidation peaks at 122 mV for Cu and–0.7 mV for brass, in cyclic voltammetry and using scanning electron microscopy (SEM). Corrosion inhibition efficiency of coated copper and brass alloy was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The impedance results showed that the inhibition efficiency of coated copper is 89% and for coated brass 79.4% compared to the uncoated copper and brass in 0.1 M H₂SO₄.

     

Chromatographic analysis of ledipasvir and sofosbuvir: New treatment for chronic hepatitis C infection with application to human plasma

Sofosbuvir (SOF) and ledipasvir (LED) are recently approved and coformulated as directly acting antiviral agents used for treatment of hepatitis C virus (HCV). A reversed phase high performance liquid chromatography - diode array detector (RP-HPLC/DAD) method was developed and validated for the first time for the analysis of newly formulated anti-HCV combination, in pure form, pharmaceutical formulation and in human plasma. In the developed method, separation was performed on Zorbax® Eclipse C18 column using a gradient mixture of acetonitrile–water as a mobile phase and scanning was performed at 260?nm (for SOF) and 330?nm (for LED). The two drugs were completely separated from each other and from plasma, where plasma peak appeared at 2.76?±?0.05?min, SOF at 4.25?±?0.05, and LED at 7.35?±?0.05. The developed method showed high sensitivity, the drugs showed linearity in the range of 1–45?µg/mL for both pure form and spiked human plasma. Three freeze–thaw cycles were performed separately at two different temperatures, ?8 and ?20°C. No significant loss of the studied drugs were observed during repeated thawing and freezing. Validation parameters such as accuracy, precision, robustness, and ruggedness were tested in compliance with USP recommendations, where acceptable results were obtained. Applying to pharmaceutical formulation showed no interference from tablet excipients.     

Ultrasound assisted microwave digestion

Simultaneous microwave and ultrasound irradiation is shown as a new technique for digestion of solid and liquid samples suitable for chemical and food analysis. Its application in analytical chemistry has been shown by decreases in digestion time: determination of copper in edible oils and total Kjeldahl nitrogen.