General Method For Preparation Research Articles

Design of transition metal oxides nanosheets for the direct electrocatalytic oxidation of glucose

The design of the morphology-controlled synthesis of two-dimensional (2D) transition metal oxides nanomaterials is a key for electrochemical oxidation of glucose. Herein, a general preparation method is adopted to develop a variety of transition metal oxides nanosheets, including cobalt oxide nanosheets (Co3O4 NS), nickel oxide nanosheets (NiO NS), copper oxide nanosheets (CuO NS), and iron oxide nanosheets (Fe3O4 NS) through a chemical reduction method followed by a hydrothermal strategy. The surface morphological characterization is performed by using transmission electron microscopic (TEM), high resolution transmission electron microscopic (HRTEM), and atomic force microscopic (AFM) measurements, revealed the two-dimensional nanosheets-like metal oxides formed. The as-developed transition metal oxide nanosheets are employed as electrocatalysts for the improved oxidation of glucose under alkaline electrolyte. The NiO nanosheets delivers best catalytic current density of ~3.1 mA cm−2 which is over- ~1.7- and ~2.6- times higher with a less positive potential, respectively in comparison to Co3O4 nanosheets and CuO nanosheets based electrodes. The morphological engineered two-dimensional nanosheets exhibit high electrochemical active sites, fast electron transfer kinetics, etc. towards the glucose oxidation reaction (GOR).

Metastable 1T'-phase group VIB transition metal dichalcogenide crystals.

Metastable 1T'-phase transition metal dichalcogenides (1T'-TMDs) with semi-metallic natures have attracted increasing interest owing to their uniquely distorted structures and fascinating phase-dependent physicochemical properties. However, the synthesis of high-quality metastable 1T'-TMD crystals, especially for the group VIB TMDs, remains a challenge. Here, we report a general synthetic method for the large-scale preparation of metastable 1T'-phase group VIB TMDs, including WS2, WSe2, MoS2, MoSe2, WS2xSe2(1-x) and MoS2xSe2(1-x). We solve the crystal structures of 1T'-WS2, -WSe2, -MoS2 and -MoSe2 with single-crystal X-ray diffraction. The as-prepared 1T'-WS2 exhibits thickness-dependent intrinsic superconductivity, showing critical transition temperatures of 8.6 K for the thickness of 90.1 nm and 5.7 K for the single layer, which we attribute to the high intrinsic carrier concentration and the semi-metallic nature of 1T'-WS2. This synthesis method will allow a more systematic investigation of the intrinsic properties of metastable TMDs.

Polymer-Coated Magnetite Nanoparticles for Protein Immobilization.

Since their discovery, magnetic nanoparticles (MNPs) have become materials with great potential, especially considering the applications of biomedical sciences. A series of works on the preparation, characterization, and application of MNPs has shown that the biological activity of such materials depends on their size, shape, core, and shell nature. Some of the most commonly used MNPs are those based on a magnetite core. On the other hand, synthetic biopolymers are used as a protective surface coating for these nanoparticles. This review describes the advances in the field of polymer-coated MNPs for protein immobilization over the past decade. General methods of MNP preparation and protein immobilization are presented. The most extensive section of this article discusses the latest work on the use of polymer-coated MNPs for the physical and chemical immobilization of three types of proteins: enzymes, antibodies, and serum proteins. Where possible, the effectiveness of the immobilization and the activity and use of the immobilized protein are reported. Finally, the information available in the peer-reviewed literature and the application perspectives for the MNP-immobilized protein systems are summarized as well.

Fabrication and Characterization of MoS2/h-BN and WS2/h-BN Heterostructures.

The general preparation method of large-area, continuous, uniform, and controllable vdW heterostructure materials is provided in this paper. To obtain the preparation of MoS2/h-BN and WS2/h-BN heterostructures, MoS2 and WS2 material are directly grown on the insulating h-BN substrate by atmospheric pressure chemical vapor deposition (APCVD) method, which does not require any intermediate transfer steps. The test characterization of MoS2/h-BN and WS2/h-BN vdW heterostructure materials can be accomplished by optical microscope, AFM, Raman and PL spectroscopy. The Raman peak signal of h-BN material is stronger when the h-BN film is thicker. Compared to the spectrum of MoS2 or WS2 material on SiO2/Si substrate, the Raman and PL spectrum peak positions of MoS2/h-BN heterostructure are blue-shifted, which is due to the presence of local strain, charged impurities and the vdW heterostructure interaction. Additionally, the PL spectrum of WS2 material shows the strong emission peak at 1.96 eV, while the full width half maximum (FWHM) is only 56 meV. The sharp emission peak indicates that WS2/h-BN heterostructure material has the high crystallinity and clean interface. In addition, the peak position and shape of IPM mode characteristic peak are not obvious, which can be explained by the Van der Waals interaction of WS2/h-BN heterostructure. From the above experimental results, the preparation method of heterostructure material is efficient and scalable, which can provide the important support for the subsequent application of TMDs/h-BN heterostructure in nanoelectronics and optoelectronics.

Efficient Preparation and Bioactivity Evaluation of Glycan-Defined Glycoproteins.

Owing to the generation of heterogeneous glycoproteins in cells, it is highly difficult to study glycoprotein-mediated biological events and to develop biomedical agents. Thus, general and efficient methods to prepare homogeneous glycoproteins are in high demand. Herein, we report a general method for the efficient preparation of homogeneous glycoproteins that utilizes a combination of genetic code expansion and chemoselective ligation techniques. In the protocol to produce glycan-defined glycoproteins, an alkyne tag-containing protein, generated by genetic encoding of an alkynylated unnatural amino acid, was quantitatively coupled via click chemistry to versatile azide-appended glycans. The glycoproteins produced by the present strategy were found to recognize mammalian cell-surface lectins and enter the cells through lectin-mediated internalization. Also, cell studies exhibited that the glycoprotein containing multiple mannose-6-phosphate residues enters diseased cells lacking specific lysosomal glycosidases by binding to the cell-surface M6P receptor, and subsequently migrates to lysosomes for efficient degradation of stored glycosphingolipids.

Preparation and dispersion stability of aqueous metal oxide nanofluids for potential heat transfer applications: a review of experimental studies

Nanofluids have recently attracted attention of many researchers due to their growing potential applications in heat transfer devices. They possess extraordinary thermal and rheological characteristics compared to the respective base fluids. However, the preparation of nanofluids and their dispersion stability is a matter of serious concern, several research investigations have been done in the present era to address these issues. Through this review article, an attempt has been made to critically analyze the published literature on the preparation and dispersion stability of different kinds of aqueous metal oxide nanofluids. In this context, general preparation and stabilization methods, types of instruments for stability inspection, as well as factors affecting stability of aqueous metal oxide nanofluids, are discussed in detail. The current research needs, possible solutions to research challenges in exploring uniformly dispersed nanofluids under optimized operating conditions is the heart of this review article. An effort has been made to determine the status as well as the possible future directions, the preparation and stability related research may take.

3D Printed Microfluidic Devices for Solid-Phase Extraction and On-Chip Fluorescent Labeling of Preterm Birth Risk Biomarkers.

Solid-phase extraction (SPE) is a general preconcentration method for sample preparation that can be performed on a variety of specimens. The miniaturization of SPE within a 3D printed microfluidic device further allows for fast and simple extraction of analytes while also enabling integration of SPE with other sample preparation and separation methods. Here, we present the development and application of a reversed-phase lauryl methacrylate-based monolith, formed in 3D printed microfluidic devices, which can selectively retain peptides and proteins. The effectiveness of these SPE monoliths and 3D printed microfluidic devices was tested using a panel of nine preterm birth biomarkers of varying hydrophobicities and ranging in mass from 2 to 470 kDa. The biomarkers were selectively retained, fluorescently labeled, and eluted separately from the excess fluorescent label in 3D printed microfluidic systems. These are the first results demonstrating microfluidic analysis processes on a complete panel of preterm birth biomarkers, an important step toward developing a miniaturized, fully integrated analysis system.

Synthesis and comparative study of emulsifying and biological properties of triazolated glucolipids

Abstract Glycolipids represent an attractive type of nonionic emulsifiers (surfactants) due to their abundant renewable resources and good biocompatibility. General preparation methods for glycolipids include enzymatic esterification or Lewis acid-catalyzed glycosylation. In this study, we report the synthesis of a novel series of triazolated alkyl glucolipids as emulsifiers by copper(I)-catalyzed click reactions, with side-chain length ranging from 4 to 10 carbons. The surface-active properties, foaming properties, emulsion properties, thermal stability as well as cytotoxicity of the synthesized compounds are evaluated to establish a comprehensive structure-property profiles, and results suggest the potential utility of medium sized glucolipids in, for example, pharmaceutical and food industries as they show superior performance than the tested commercial references.

Asymmetric Membranes: A Potential Scaffold for Wound Healing Applications

Currently, due to uprising concerns about wound infections, healing agents have been regarded as one of the major solutions in the treatment of different skin lesions. The usage of temporary barriers can be an effective way to protect wounds or ulcers from dangerous agents and, using these carriers can not only improve the healing process but also they can minimize the scarring and the pain suffered by the human. To cope with this demand, researchers struggled to develop wound dressing agents that could mimic the structural and properties of native skin with the capability to inhibit bacterial growth. Hence, asymmetric membranes that can impair bacterial penetration and avoid exudate accumulation as well as wound dehydration have been introduced. In general, synthetic implants and tissue grafts are expensive, hard to handle (due to their fragile nature and poor mechanical properties) and their production process is very time consuming, while the asymmetric membranes are affordable and their production process is easier than previous epidermal substitutes. Motivated by this, here we will cover different topics, first, the comprehensive research developments of asymmetric membranes are reviewed and second, general properties and different preparation methods of asymmetric membranes are summarized. In the two last parts, the role of chitosan based-asymmetric membranes and electrospun asymmetric membranes in hastening the healing process are mentioned respectively. The aforementioned membranes are inexpensive and possess high antibacterial and satisfactory mechanical properties. It is concluded that, despite the promising current investigations, much effort is still required to be done in asymmetric membranes.

FeNi Nanoparticles Embedded in Porous Nitrogen-Doped Graphene for Electrocatalytic Evolution of Hydrogen and Oxygen

The thermal annealing method is regarded as a general and promising method for preparation of carbon-based electrocatalysts. However, this method always suffers from complex and harsh preparative c...

Nanoparticulate targeted drug delivery systems - A Review

Nanoparticulate drug delivery system are the rapidly developing system, and nanoparticles are present in the size range of 1-100nm. Nanoparticles composed of various thermal, electrical, and optical property. Nanoparticles offers the potential advantages over the traditional dosage forms it is ascribable to the properties of nanoparticles. Nanoparticulate drug delivery system ensures the site-specific delivery of a drug(Targeting drug delivery) and aids in improving the efficacy of the new as well as old drugs and has the potential in crossing the various physiological barriers and also improves the therapeutic index of the drugs and increases the patient compliance. The objectives of this review is to classify the nanoparticles based on the different groups, surface properties of nanoparticles, describe the strategies of drug targeting, the necessity of nanoparticles their general method of preparation, different methods used in characterization, self- assembly and mechanism of drug release in a systemic manner. The potential advantages and limitations of various nanoparticulate drug delivery systems are also discussed elaborately.

Bio-Based Polymer Electrolytes for Electrochemical Devices: Insight into the Ionic Conductivity Performance.

With the continuing efforts to explore alternatives to petrochemical-based polymers and the escalating demand to minimize environmental impact, bio-based polymers have gained a massive amount of attention over the last few decades. The potential uses of these bio-based polymers are varied, from household goods to high end and advanced applications. To some extent, they can solve the depletion and sustainability issues of conventional polymers. As such, this article reviews the trends and developments of bio-based polymers for the preparation of polymer electrolytes that are intended for use in electrochemical device applications. A range of bio-based polymers are presented by focusing on the source, the general method of preparation, and the properties of the polymer electrolyte system, specifically with reference to the ionic conductivity. Some major applications of bio-based polymer electrolytes are discussed. This review examines the past studies and future prospects of these materials in the polymer electrolyte field.

A Pharmaceutical And Preliminary Analytical Study On Ksheerinivruksha ArkaEditor in Chief RGUHS Journal of AYUSH Sciences

INTRODUCTION Arka Kalpana is one among the Pancha Vidha Kashaya Kalpana according to Arka Prakasha. Arka is a unique preparation in which the water soluble active principles are extracted from different drugs through distillation methods. Ksheerinivruksha Arka mentioned in Arka Prakasha is indicated in Vrana Ulcer Medhoroga Hyperlipidaemia Visarpa Herpes zoster.METHODOLOGY In this study Ksheerinivruksha Arka is prepared with a 110 drug to water ratio and as the general method of preparation 60 of the distillate is collected out of total volume. An attempt has been made to prepare Ksheerinivruksha Arka and to check its Organoleptic characters such as appearance taste odour and Physico-chemical analysis such as Viscosity Refractive index RI Total Suspended Solids TSS Specific gravity pH Boiling point and Volatile oil content.RESULT Clear transparent colourless liquid- Arka is obtained with characteristic odour and taste indicating the presence of the drug constituents in it. Physico-chemical analysis is repeated three times and the average value is calculated and noted.DISCUSSION Its Organoleptic characters are similar to that of Arka standard protocol. As per Physico-chemical analysis it is slightly acidic in nature with specific gravity and boiling point almost close to that of water as it is a water distillate along with other relevant parameters.

Synthesis and characterization of size controlled alloy nanoparticles

AbstractBimetallic and multimetallic alloy nanoparticles are emerging as a class of critical nanomaterials in electronic, optical and magnetic fields due to their unique physic-chemical properties. In particular, precise control of the nanoparticle size can endow them with broad versatility and high selectivity. This chapter reviews some tremendous achievements in the development of size controlled bimetallic and multimetallic alloy nanoparticles, with special emphasis on general preparation methods, characterization methodologies and instrumentation techniques. Some key factors and future perspectives on the development of size-controlled bimetallic and multimetallic alloy nanoparticles are also discussed.

Synthesis, Principles, and Properties of Magnetite Nanoparticles for In Vivo Imaging Applications-A Review.

The current nanotechnology era is marked by the emergence of various magnetic inorganic nanometer-sized colloidal particles. These have been extensively applied and hold an immense potential in biomedical applications including, for example, cancer therapy, drug nanocarriers (NCs), or in targeted delivery systems and diagnosis involving two guided-nanoparticles (NPs) as nanoprobes and contrast agents. Considerable efforts have been devoted to designing iron oxide NPs (IONPs) due to their superparamagnetic (SPM) behavior (SPM IONPs or SPIONs) and their large surface-to-volume area allowing more biocompatibility, stealth, and easy bonding to natural biomolecules thanks to grafted ligands, selective-site moieties, and/or organic and inorganic corona shells. Such nanomagnets with adjustable architecture have been the topic of significant progresses since modular designs enable SPIONs to carry out several functions simultaneously such as local drug delivery with real-time monitoring and imaging of the targeted area. Syntheses of SPIONs and adjustments of their physical and chemical properties have been achieved and paved novel routes for a safe use of those tailored magnetic ferrous nanomaterials. Herein we will emphasis a basic notion about NPs magnetism in order to have a better understanding of SPION assets for biomedical applications, then we mainly focus on magnetite iron oxide owing to its outstanding magnetic properties. The general methods of preparation and typical characteristics of magnetite are reviewed, as well as the major biomedical applications of magnetite.

A helix-shaped polyaniline/sulfur nanowire as novel structure-accommodable lithium-sulfur battery cathode for high-performance electrochemical lithium-storage

The volume-change and poor conductivity issues of sulfur severely restrict the performance of lithium-sulfur (Li–S) batteries. Herein, we present a novel spring-shaped composite in which the sulfur is coated on helix-structured SiO2@hydrogel nanowires. The helix composite provides a buffer space for the volume-change of sulfur during charge and discharge; and the hydrogel polyaniline (PANI) coating improves the conductivity of the electrode and enables interaction with sulfides which is demonstrated by first-principle modelling. The prepared SiO2@C@PANI/S nanowires exhibit a stable capacity of 940 mAh g−1 after 120 cycles at a rate of 0.1C, along with a good Coulombic efficiency of 99.8%. The nanowires-based cathode also shows a high rate-performance even after three rounds of repeated measurements. The high performance and the general preparation method would enable the composite to be able to find significant applications for electrochemical energy-storage.

Amorphous Oxide Nanostructures for Advanced Electrocatalysis.

Amorphous oxides have attracted special attention as advanced electrocatalysts owing to their unique local structural flexibility and attractive electrocatalytic properties. With abundant randomly oriented bonds and surface-exposed defects (e.g., oxygen vacancies) as active catalytic sites, the adsorption/desorption of reactants can be optimized, leading to superior catalytic activities. Amorphous oxide materials have found wide electrocatalytic applications ranging from hydrogen evolution and oxygen evolution to oxygen reduction, CO2 electroreduction and nitrogen electroreduction. The amorphous oxide electrocatalysts even outperform their crystalline counterparts in terms of electrocatalytic activity and stability. Despite of the merits and achievements for amorphous oxide electrocatalysts, there are still issues and challenges existing for amorphous oxide electrocatalysts. There are rarely reviews specifically focusing on amorphous oxide electrocatalysts and therefore it is imperative to have a comprehensive overview of the research progress and to better understand the achievements and issues with amorphous oxide electrocatalysts. In this minireview, several general preparation methods for amorphous oxides are first introduced. Then, the achievements in amorphous oxides for several important electrocatalytic reactions are summarized. Finally, the challenges and perspectives for the development of amorphous oxide electrocatalysts are outlined.

Catalysts of the preparation and industrial importance of catalysis and catalyst deactivation

A catalyst is a substance which increases the rate at which a chemical reaction approaches equilibrium without becoming itself permanently involved, Types of Catalysis (homogeneously catalyzed and Heterogeneous catalysis), Industrial Importance of Catalysis: Catalysts are the workhorses of chemical transformations in the industry. Classification of Catalysts :( Unsupported (Bulk) Catalysts, Supported Catalysts).General Methods of Preparation for Supported Catalyst Systems: (Impregnation, Adsorption from Solution, Chemical Vapour Deposition (CVD), Co-precipitation, Deposition, Regenerability). Catalyst design parameters: (Activity, Stability, Selectivity). Catalyst deactivation: deactivation leads to a shortened catalyst lifetime, and the replacement of an aged catalyst to a new one is determined by the industrial processes for which the catalyst is used.

General method of specimen preparation for the quantitative microscopic characterization of nano- and microparticles

Nano-materials are a subject of current research and development due to their special characteristics, based on the size of their constituent particles. A major hurdle is the reliable analysis of the particle size and particle size distribution. This article introduces a new method of specimen preparation for the quantitative analysis of particle systems. Selected examples show the capabilities of computer-assisted image analysis of microscopic images. The problem of agglomeration and aggregation of primary particles is discussed and a strategy for calculating the primary particle distribution based on a mathematical model is presented. The successful, highly controlled deposition of deagglomerated nanoparticles on a microscope carrier enables a reliable particle size distribution measurement, even with strong interacting nanoparticles.

Synthetic Approaches to Nitro-Substituted Isoxazoles

Nitro-substituted isoxazoles are of utmost interest both as versatile intermediates for targeted organic synthesis and as perspective bioactive compounds for drug development. Nevertheless, the existing approaches to them usually lack generality and strongly depend on the position of the nitro group and on the presence of other substituents in the isoxazole ring. This review provides the first systematization of all available data concerning synthetic approaches to 3-, 4-, and 5-nitroisoxazoles. There are a number of preparative approaches to 4-nitroisoxazoles based on classical heterocyclization reactions of nitro-substituted compounds and the nitration of isoxazoles. 3-Nitro- and, especially, 5-nitroisoxazoles are much less readily available. A few methods affording 3-nitroisoxazoles have been reported, often employing the heterocyclization of unsaturated compounds by treatment with sodium nitrite. The sole general preparative method for 5-nitroisoxazoles, containing a variety of functional groups, employs the heterocyclization of electrophilic alkenes by treatment with tetranitromethane activated with triethylamine.1 Introduction2 Synthesis of 4-Nitroisoxazoles2.1 Nitration of Isoxazoles2.2 Condensations of α-Nitro Ketones or Their Oximes2.3 1,3-Dipolar Cycloaddition of Nitrile Oxides to Acetylenes and Their Synthetic Equivalents2.4 Heterocyclization of Acetylene Derivatives by Treatment with Sodium Nitrite2.5 Heterocyclization of Nitro Derivatives of 1,3-Diketones and Their Synthetic Equivalents2.6 Miscellaneous Methods3 Synthesis of 3-Nitroisoxazoles3.1 Heterocyclization of Acetylene Derivatives or 1,3-Dihalogenoalkenes by Treatment with Sodium Nitrite3.2 Heterocyclization of Morita–Baylis–Hillman Acetates by Treatment with Sodium Nitrite3.3 1,3-Dipolar Cycloadditions4 Synthesis of 5-Nitroisoxazoles4.1 1,3-Dipolar Cycloadditions4.2 Synthesis Using Polynitro Compounds5 Conclusion