Influence Of Zro2 on The Physicochemical Properties of Phosphate-Based Glasses and Glass Ceramics

Abstract

Phosphate-based bioactive glasses and their glass ceramics for 47P₂O₅– (30.5)CaO–(22.5 ? x)Na₂O–xZrO₂ for different ZrO₂ contents (x = 0, 1.5, 3.0, 4.5, and 6.0 mol%) were prepared through melt quenching and controlled heat treatment procedures. The amorphous nature of glasses and the presence of crystalline phases in glass ceramics were studied by means of X-ray diffraction (XRD) studies. The density, molar volume, ultrasonic velocities, attenuation, elastic constants, and microhardness of glass and glass ceramics were used to study the structural changes. The formation of hydroxyapatite layer on the surface of glasses and glass ceramics after immersion in simulated body fluid (SBF) was explored through XRD, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) analyses. The results indicate that the added ZrO₂ increases the crosslink density of glasses, resulting in network stability, and also induces the formation of an apatite layer on the surface of glasses.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Triazine interlinked covalent organic polymer as an efficient anti-bacterial agent

Herein, we report the synthesis of new covalent organic polymer comprising triazine and o-tolidine by solvothermal method. The formation of polymer was confirmed by Fourier transform infra red spectroscopy (FT-IR), cross polarization–magic angle spinning nuclear magnetic resonance (NMR), transmission electron microscopy, and scanning electron microscopy. Their antibacterial activity toward S. aureus (gram-positive) and P. aeruginosa (gram-negative) was assessed by the optical density measurements and direct contact method. These results have great significance toward the design of new porous polymers for antibacterial applications.     

Physicochemical properties of new cellulosic Artisdita hystrix leaf fiber

The characterization of new natural fiber is increasing due to its excellent properties. This drives investigators to create high performance composites. The present investigation was designed to study the physicochemical properties of fibers obtained from the leaf of the Artistida hystrix. The Artistida hystrix fibers (AHFs) had crystallinity index (44.85%), cellulose (59.54 wt%), hemicellulose (11.35 wt%), lignin (8.42 wt%), and density (540 kg m^?3). The tensile strength of AHFs was 440 ± 13.4 MPa with an average strain rate of 1.57 ± 0.04%. The calculated microfibril angle of AHFs was 12.64 ± 0.45°, which influenced the mechanical properties.     

An Overview of Metal-Organic Framework Based Electrocatalysts: Design and Synthesis for Electrochemical Hydrogen Evolution,Oxygen Evolution,and Carbon Dioxide Reduction Reactions

Due to the increasing global energy demands, scarce fossil fuel supplies, and environmental issues, the pursued goals of energy technologies are being sustainable, more efficient, accessible, and produce near zero greenhouse gas emissions. Electrochemical water splitting is considered as a highly viable and eco-friendly energy technology. Further, electrochemical carbon dioxide (CO₂) reduction reaction (CO₂RR) is a cleaner strategy for CO₂ utilization and conversion to stable energy (fuels). One of the critical issues in these cleaner technologies is the development of efficient and economical electrocatalyst. Among various materials, metal-organic frameworks (MOFs) are becoming increasingly popular because of their structural tunability, such as pre- and post- synthetic modifications, flexibility in ligand design and its functional groups, and incorporation of different metal nodes, that allows for the design of suitable MOFs with desired quality required for each process. In this review, the design of MOF was discussed for specific process together with different synthetic methods and their effects on the MOF properties. The MOFs as electrocatalysts were highlighted with their performances from the aspects of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical CO₂RR. Finally, the challenges and opportunities in this field are discussed.     

Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes of 2-nitrobenzoic acid with methyl carbazate as ancillary ligand. Crystal structure of the copper(II) complex

Divalent metal complexes of general formula [M(2-nb)₂(mc)₂].2(2-nbH), where M = Co(II), Ni(II), Cu(II) or Zn(II), 2-nbH = 2-nitrobenzoic acid and mc = methyl carbazate (NH₂NHCOOCH₃), have been prepared and characterized by physicochemical and spectroscopic methods. Single-crystal X-ray study of the Cu(II) complex revealed that the molecule is centrosymmetric, with two N,O-chelating mc ligands in equatorial positions and a pair of monodentate 2-nb anions in the axial positions. The lattice 2-nbH molecules help to establish the packing of monomers through hydrogen-bonding interactions. Thermal stability and reactivity of the complexes were studied by TG–DTA. Emission studies show that these complexes are fluorescent.     

Tilianin: A Potential Natural Lead Molecule for New Drug Design and Development for the Treatment of Cardiovascular Disorders

Cardiovascular disorders (CVDs) are the leading risk factor for death worldwide, and research into the processes and treatment regimens has received a lot of attention. Tilianin is a flavonoid glycoside that can be found in a wide range of medicinal plants and is most commonly obtained from Dracocephalum moldavica. Due to its extensive range of biological actions, it has become a well-known molecule in recent years. In particular, numerous studies have shown that tilianin has cardioprotective properties against CVDs. Hence, this review summarises tilianin’s preclinical research in CVDs, as well as its mechanism of action and opportunities in future drug development. The physicochemical and drug-likeness properties, as well as the toxicity profile, were also highlighted. Tilianin can be a natural lead molecule in the therapy of CVDs such as coronary heart disease, angina pectoris, hypertension, and myocardial ischemia, according to scientific evidence. Free radical scavenging, inflammation control, mitochondrial function regulation, and related signalling pathways are all thought to play a role in tilianin’s cardioprotective actions. Finally, we discuss tilianin-derived compounds, as well as the limitations and opportunities of using tilianin as a lead molecule in drug development for CVDs. Overall, the scientific evidence presented in this review supports that tilianin and its derivatives could be used as a lead molecule in CVD drug development initiatives.     

Preparation and characterization of biodegradable sugarcane bagasse nano reinforcement for polymer composites using ball milling operation

The present work includes the processing and characterization of nano-based natural reinforcement for polymer composite materials. Sugarcane bagasse has been collected and the fibers were extracted using manual striping process. Undesirable materials present in the extracted fibers were removed by 1% NaOH-based chemical treatment. The macrofibers were reduced to nano scale by using high-energy ball milling process. Nanoparticles from bagasse fibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The degree of crystallinity of nano bagasse is 55.2% and it was reported by using XRD. A FTIR spectrum confirms the presence of cellulose functional groups in nano bagasse. The nano bagasse dimensions and morphology were investigated using SEM. The average length and diameter of the nano bagasse is 51.2 and 46.1 nm, respectively. Thermal stability of the nano bagasse was revealed by TGA analysis. The chemical composition of cellulose, lignin, and hemicellulose contents was also investigated.     

Simultaneous estimation of hydroxychavicol and chlorogenic acid from Piper betel L. through RP-HPLC

A RP-HPLC method was developed (λ (max)?=?280) to quantify hydroxychavicol and chlorogenic acid in Piper betel Linn. The method was validated for linearity, limit of detection (LOD?=?3:1σ/S), limit of quantification (LOQ?=?10:1σ/S), precision, accuracy and ruggedness. The response was linear with good correlation between concentration and mean peak area through a coefficient of determinants (r (2)) of 0.9940, y?=?1.98e?+?004x?+?5.19e?+?004 and 0.9945, y?=?2.76e?+?004x?+?1.40e?+?005 with LOD 1.6?μg?mL(-1), 1.0?μg?mL(-1) and LOQ 5.0?μg?mL(-1) and 3.0?μg?mL(-1), respectively, for hydroxychavicol (28.56% w/w) and chlorogenic acid (0.40% w/w). The %RSD of precision and recovery of hydroxychavicol and chlorogenic acid were <2.0%. The proposed method was simple, accurate, specific, precise and reproducible.     

Mesoporous and biocompatible surface active silica aerogel synthesis using choline formate ionic liquid

In this paper, we report the preparation and characterization of mesoporous and biocompatible transparent silica aerogel by the sol-gel polymerization of tetraethyl orthosilicate using ionic liquid. Choline cation based ionic liquid allows the silica framework to form in a non collapsing environment and controls the pore size of the gel. FT-IR spectra reveal the interaction of ionic liquid with surface -OH of the gel. DSC thermogram giving the evidence of confinement of ionic liquid within the silica matrix, which helps to avoid the shrinkage of the gel during the aging process. Nitrogen sorption measurements of gel prepared with ionic liquid exhibit a low surface area of 100.53 m2/g and high average pore size of 3.74 nm. MTT assay proves the biocompatibility and cell viability of the prepared gels. This new nanoporous silica material can be applied to immobilize biological molecules, which may retain their stability over a longer period.     

Quantum chemical calculation,topological analysis,biological evaluation and molecular docking of allo-ocimenol against breast cancer

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