Nm In Average Size Research Articles

Formulation and Preparation of Water-In-Oil-In-Water Emulsions Loaded with a Phenolic-Rich Inner Aqueous Phase by Application of High Energy Emulsification Methods.

Currently, industry is requesting proven techniques that allow the use of encapsulated polyphenols, rather than free molecules, to improve their stability and bioavailability. Response surface methodology (RSM) was applied in this work to determine the optimal composition and operating conditions for preparation of water-in-oil-in-water (W/O/W) emulsions loaded with phenolic rich inner aqueous phase from olive mill wastewater. A rotor-stator mixer, an ultrasonic homogenizer and a microfluidizer processor were tested in this study as high-energy emulsification methods. Optimum results were obtained by means of microfluidizer with 148 MPa and seven cycles input levels yielding droplets of 105.3 ± 3.2 nm in average size and 0.233 ± 0.020 of polydispersity index. ζ-potential, chemical and physical stability of the optimal W/O/W emulsion were also evaluated after storage. No droplet size growth or changes in stability and ζ-potential were observed. Furthermore, a satisfactory level of phenolics retention (68.6%) and antioxidant activity (89.5%) after 35 days of storage at room temperature makes it suitable for application in the food industry.

Recyclable Fe3O4@C nanocomposite as potential adsorbent for a wide range of organic dyes and simulated hospital effluents

Abstract The present work reported the utilization of Fe3O4@C nanocomposite for removing a series of six organic dyes from aqueous solutions and dealing with simulated hospital effluents. Single-step fabrication of magnetic Fe3O4@C nanocomposite was facilely performed at 500 °C. This material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Core–shell Fe3O4 NPs ( ∼ 40 nm in average size) were dispersed well and encapsulated by ultrathin carbon coatings with the thickness of 4–5 nm. Fe3O4@C nanocomposite owned surface functional groups important for dyes adsorption. The adsorption results showed that maximum adsorption capacity values of organic dyes on Fe3O4@C obeyed an order as follows: methyl orange (38.03 mg/g) rhodamine B (87.32 mg/g) methylene blue (95.61 mg/g) methyl red (153.1 mg/g) congo red (165.3 mg/g) crystal violet (181.6 mg/g). Two simulated hospital effluents could also be treated from 63.6–84.5% using this nanocomposite. In addition, Fe3O4@C could be reused up to 5 cycles without considerable decrease in uptake capacity.

Synthesis, characterization, biological activities and molecular docking of Epilobium parviflorum aqueous extract loaded chitosan nanoparticles

Epilobium is a medicinal plant; its extracts are widely used traditional medicine due to their broad range of pharmacological and therapeutic properties. Its most prominent feature is its therapeutic effects on prostatic diseases. The aim of this study is preparation of controlled release system of Epilobium parviflorum, and determination of its potential of anticancer applications. For this purpose, Epilobium parviflorum extract (EPE) loaded chitosan nanoparticles were prepared with ionic gelation method to increase the bioavailability of the extract. The nanoparticles were investigated in terms of size, zeta potential, polydispersity index, encapsulation efficiency, loading capacity and release profile. Besides, scanning electron microscopy (SEM) was used to observe the morphology of the nanoparticles. Moreover, Ames/Salmonella test was used to determine the mutagenicity of EPE, and it was shown that it had no mutagenic effect. It was found that EPE loaded chitosan nanoparticles were with 64.47 nm in average size, 0.168 PdI and 15.2 mV zeta potential. Encapsulation efficiency and loading capacity were found as 92.46% and 8%, respectively. Finally, DNA binding assay and in silico molecular docking studies were performed between EPE and DNA in order to contribute to design of plant based controlled release system for use in cancer therapy.

Caffeine degradation in synthetic coffee wastewater using silverferrite nanoparticles fabricated via green route using Amaranthus blitum leaf aqueous extract

Caffeine is a persistent chemical with toxic effects on various biological systems in the environment which initiates the necessity to degrade the caffeine. This study aimed to degrade caffeine using Amaranthus blitum leaf extract mediated silverferrite nanoparticles (AgFeO2-NPs) under compact fluorescent lamp illumination in shake flask by photocatalysis. The AgFeO2 NPs were monodispersed with spherical shape (92 nm in average size and bandgap of 1.9 eV), holds higher photocurrents and surface area of 10.4 μA/cm2 and 145.21 m2/g respectively. The effect of different operating conditions such as initial pH (4, 7and 9), AgFeO2 NPs loading (10, 20, 50, and 100) mg/L, and caffeine concentration (10, 20, 50 and 100) ppm was studied on degradation efficiency. The results showed that optimal conditions led to maximum degradation of 99.9% at pH 9.0, 50 mg/L NPs dose with initial caffeine concentration of 50 ppm in 15 h compared to photolysis and NPs under dark condition. Under optimized conditions, (∼ 120 ppm caffeine in synthetic wastewater, pH 9.3, and 50 mg/L of AgFeO2 NPs), it was found that 95% degradation occurred in 24 h. Also, AgFeO2 NPs found to degrade polyphenols under light conditions suggesting a potential catalyst for treating caffeine wastewater.

Preparation of micron Si@C anodes for lithium ion battery by recycling the lamellar submicron silicon in the kerf slurry waste from photovoltaic industry

It is significant to find a green path in recycling the silicon powder in the kerf slurry wastes from photovoltaic industry to produce high performance lithium ion batteries anodes. In this study, we found that, the submicron silicon particles from the kerf wastes, 471.5 nm in average size, is lamellar, which is inhomogeneous in three-dimensional sizes with one coordinate direction < 100 nm. Herein, the glucose is selected as carbon source, and nickel nitrate hexahydrate is added as catalyst to construct a micron Si@C core-shell structure by hydrothermal method. The as prepared micron Si@C anode retains 1788.9 mA h g−1 after 200 cycles at a current density of 0.1 C. It retains 1446.8 mA h g−1 after a rate testing from 0.1 C to 1 C and is stabilized at ~3000 mA h g−1 when the current density was restored to 0.1 C. Theoretically, a structure with carbon core and lamellar silicon shell provides ample space in the Z direction to accommodate the volume expansion of Li+ intercalation. Simultaneously, it generates a perfect contact for electron and ion transportation between the core and shell in the X and Y direction. Therefore, a fantastic electrochemistry performance can be achieved.

Preparation of cationic fluorinated acrylate copolymer latex and its application on cotton fabric

Coupled with the improvement in people’s living standards, the demand for textiles having a special performance like water repellency is mushrooming. In this study, the cationic fluorinated acrylate copolymer latex particles with a core–shell structure were synthesized via semicontinuous seed emulsion polymerization process, using Span 80, Tween 80, and dodecyltrimethylammonium chloride as composite emulsifier and (2-(acryloyloxy)ethyl)trimethylammonium chloride as a cationic monomer. Cationic fluorinated acrylate copolymers were successfully confirmed through the FTIR, 1H NMR, and XPS analyses. In addition, the homogeneous latex particles (~ 132 nm of average size) with an evident core–shell structure were observed by TEM analysis, and a stable positive charge (48 ± 5 mV) on the surface of latex particles was demonstrated by zeta potential analysis. Meanwhile, the results showed that the dosage of dodecafluoroheptyl methacrylate (DFMA) played a vital role in the hydrophobicity of the latex films and the one with the best water repellency was identified with 10 g of DFMA dosage. Furthermore, the cotton fabric finishing experiments demonstrated that, after finishing by the cationic fluorinated acrylate copolymer emulsion, the treated cotton fabric exhibited excellent hydrophobicity even at low concentration, with > 130° of the water contact angle and > 60 min of the static absorbing time.

Nanomodified Screen-Printed Electrode for direct determination of Aflatoxin B1 in malted barley samples

The present work describes a facile synthesis of a nanocomposite based on gold nanoparticles (NPAu) and graphene quantum dots (GQD) and its use as an electrode modifier for a non-biological alternative of Aflatoxin B1 (AFB1) voltammetric determination. TEM and SEM techniques showed a uniform and well-distributed dispersion of gold nanoparticles (19 ± 6 nm of average size) and GQD, which was used as a reducing and stabilizing particle formation. Modified screen-printed electrode (NPAuGQD-SPE) was characterized by electrochemical experiments, as linear voltammetry and electrochemical impedance spectroscopy. A significative electrocatalytic effect was observed towards AFB1 oxidation using the proposed device, shifting the peak potential to less positive values and improving the voltammetric response. EIS experiments showed lower RCT values for the modified electrodes, calculated as 117 Ω, 14.9 kΩ, and 40.3 kΩ for NPAuGQD-SPE, GQD-SPE, and SPE, respectively. Under optimized conditions, an analytical curve with linear region of 1.0–50.0 nmol L−1 was obtained, reaching detection and quantification limits of 0.47 and 1.5 nmol L−1, respectively. Samples of malted barley were fortified based on the maximum residue limit (MRL) allowed by Brazilian legislation, and recoveries in the range of 76–103% were obtained, indicating that there is no significant matrix effect, considering the low concentration values used and simple sample treatment.

Evaluation of additive electron beam melting of haynes 282 alloy

The electron beam melting (EBM) process is an attractive additive manufacturing technology that can be applied to a number of different materials. However, fabrication of each material requires tweaking and identifying optimal processing parameters. In this study, process parameters were successively varied to identify a processing regime to fabricate the nickel-base (Ni-base) superalloy Haynes 282. Key parameters to minimize porosity and mitigate the potential for cracking were beam velocity, beam current, hatch spacing, line order, and beam focus. Overall, the EBM process window produced a combination of promising microstructure and 99.5% dense material with no observable cracking. Electron backscatter diffraction revealed a crystallographic texture along the [001] direction of the cube orientation aligned with the build direction. Within the grain interiors of the as-fabricated material were observed uniformly distributed γ′ precipitates with a size distribution ranging from ~80 nm spherical to ~190 nm cuboidal particles with an average particle size of ~128 nm. Grain boundary carbides were observed in two morphologies: blocky and thin film–like. Hardness and tensile testing of the as-fabricated EBM material indicated a 10% higher hardness and slightly lower tensile strength compared with the as-annealed wrought form of the Haynes 282 alloy. The EBM alloy exhibited pronounced ductility except at T > 600 °C perpendicular to the build direction. Annealing based on standard wrought heat treatments showed that γ′ precipitates measuring 20–30 nm in average size can be achieved to improve the alloy's high-temperature performance.

Graphene anchored with super-tiny Ni nanoparticles for high performance electromagnetic absorption applications

This paper reports a facile strategy for one-step synthesis of graphene anchored with super-tiny (< 5 nm) nickel nanoparticles (graphene@Ni) with high perfomance microwave absorption. The phase structure, morphology and magnetism of graphene@Ni were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM), respectively. The magnetic Ni nanoparticles with 2.45 nm in average size are densely anchored on the surface of graphene. The electromagnetic characteristics of graphene@Ni compounds were measured by vector network analyzer using a coaxial line method in the frequency range of 1–18 GHz. The reflection loss (RL) of graphene@Ni reaches − 53.92 dB at 9.5 GHz with a thickness of 2.8 mm, and the maximum effective absorption bandwidth with RL values lower than − 10 dB is 5.44 GHz covering from 11.45 to 16.89 GHz at a thickness of 2.1 mm, showing that both of the RLmin and absorption bandwidth for graphene@Ni are obviously enhanced with thinner thickness compared to pure Ni NPs and graphenes. The real RL of graphene@Ni modified aramid fabrics/bismaleimide composite laminate is also measured for comparison, which is basically consistent with simulated results of graphene@Ni. Therefore, the graphene@Ni compounds have advantage in practice for high performance microwave absorption applications.

Antiproliferative effects of new magnetic pH-responsive drug delivery system composed of Fe3O4, CaAl layered double hydroxide and levodopa on melanoma cancer cells

In this study, an efficient drug delivery system composed of Fe3O4, CaAl layered double hydroxide (LDH) and l-Dopa has been synthesized through hydrogen bonds between l-Dopa and CaAl-LDH encapsulated Fe3O4 nanoparticles (Fe3O4@CaAl-LDH@l-Dopa). The structural features of Fe3O4@CaAl-LDH@l-Dopa were characterized using XRD, SEM, TEM, EDX, FT-IR, VSM, TGA, XPS, zeta potential analysis and BET. All of the characterization techniques show the uniform high surface area core-shell structure with about 120 nm in average size. Also, the obtained results clearly indicate that this drug delivery system possess high potent for adsorption of l-Dopa (52 wt%) and high drug encapsulation efficiency (71%). The amount of l-Dopa release in low pHs (53.8%) which simulates the environment of cancer cells is greater than higher pHs. The in vitro cytotoxic and anticancer activities of Fe3O4@CaAl-LDH@l-Dopa were investigated against Mel-Rm Cells Melanoma (NCIt: C3224) using LDH colorimetric assay and differential staining cell death assay. The results showed Fe3O4@CaAl-LDH@l-Dopa with a lower concentration of l-Dopa, illustrate a higher cytotoxicity and anticancer activity.

Ultra-fast spill oil recovery using a mesoporous lignin based nanocomposite prepared from date palm pits (Phoenix dactylifera L.).

Oil spills present the enormous harm to the environment, and its potential remediation for environmental protection is import worldwide. Herein, we report an effective strategy inspired by the lignin based bio-waste date palm pits powder (Phoenix dactylifera L.), which was modified with magnetic Fe3O4 nanocrystals and used as a porous, hierarchical graphite carbon oil/solvent sorption magnetic materials. The fabricated nanocomposite (Fe3O4@MPC) was characterized using several analytical techniques. The results revealed that Fe3O4 nanoparticles with a 22 nm in average size were embedded into the graphite carbon matrix. The rate of sorption, sorption capacity, oil retention, water uptake, adsorption isotherm model, and kinetic behavior were evaluate and >85% of both oils were adsorbed, onto Fe3O4@MPC surface in the first 30 min followed by equilibrium in both type of aqueous solution. The batch equilibrium data supported the Langmuir isotherm model with the adsorption capacity about to 23.01 mg/g. The kinetics data was well fitted with pseudo-second-order kinetic model. After saturation, the Fe3O4@MPC was recycled using ethanol and reused for further cycle. The fabricated nanocomposite exhibited a significant dual oleophilic and hydrophobic nature that can be applicable for oil removal from oil-contaminated wastewaters. Meanwhile, the magnetic properties allowed Fe3O4@MPC to be separated conveniently and effectively from the solution and used as oil absorbent without touching the oil.

Facile synthesis of Cu2O particles with different morphologies

Cu2O particles with cubic, octahedral, truncated octahedral and cubic truncated morphologies were synthesized using a simple chemical reduction method at room temperature. The nanocrystals were synthesized directly in aqueous solution by varying the molar concentration of CuCl2 precursor salt added to the sodium borohydride NaBH4 as a reducing agent. The solids obtained were characterized by ultraviolet-visible spectroscopy (UV–vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). UV–vis absorption spectra exhibit peaks with characteristic wavelengths of Cu2O. SEM and TEM reveal particles with a cubic morphology at 15 mM CuCl2, with an average particle size of 100 nm. Cu2O particles are also grown in an octahedral shape at 16 mM of CuCl2, having an average particle size of 150 nm. Finally, truncated octahedral and truncated cubic forms were produced for concentrations in the range of 17–20 mM with 100 nm of average size.

Angelica sinensis polysaccharide encapsulated into PLGA nanoparticles as a vaccine delivery and adjuvant system for ovalbumin to promote immune responses

Nanoparticles (NPs)-based vaccine delivery systems are widely used for their ability to control the release of antigens and promote immune responses against cancer or infectious diseases. In this study, the immunopotentiator Angelica sinensis polysaccharide (ASP) and model protein antigen ovalbumin (OVA) were encapsulated into Poly(lactic-co-glycolic acid) (PLGA) to formulate the novel NPs-based vaccine delivery system (ASP-PLGA/OVA). These formulations were subcutaneously administered to mice, then the magnitude and kinetics of antibody and cellular immune responses were assessed. The ASP-PLGA/OVA NPs were pherical in shape with smooth surfaces, approximately 225.2 nm in average size, negatively charged (around −11.27 mV), and the encapsulation efficiency of OVA at around 66.28%, respectively. Furthermore, ASP-PLGA/OVA NPs could keep stable at 4 °C over 30 days and provide a sustained and controlled release of OVA from the NPs. The results demonstrated that mice immunized with ASP-PLGA/OVA NPs could significantly enhance lymphocyte proliferation and improve the ratio of CD4+ to CD8+ T cells, thereby ASP-PLGA/OVA NPs could induce a strong cellular immune response. Moreover, the ASP-PLGA/OVA NPs could induce vigorous and long-term IgG immune responses with a mixed Th1 and Th2 responses and up-regulate the levels of Th-associated cytokines. These results suggested that ASP-PLGA/OVA NPs, which stimulated strong and continuous antibody responses and induced cellular immune responses, could potentially serve as an efficient and safe vaccine delivery and adjuvant system against infections and diseases.

Synthesis of Cu Nanoparticles Using Copper Carbonate as Cu Source Toward Versatile Applications.

Cu nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were fabricated by polyol method using copper carbonate as a raw material. To increase the reaction temperature, glycol multimers such as diethylene glycol, triethylene glycol, or tetraethylene glycol were examined as a solvent. With increasing degree of multimerization, average diameter of Cu NPs decreased. The synthesis of Cu NPs was further investigated by changing reaction temperature, the amount and molecular weight of PVP in triethylene glycol as a solvent. Average diameter and standard deviation of Cu NPs were found to be highly dependent on those factors. As a result, fine Cu NPs ranging from 28 to 67 nm in average size with narrow size distribution (standard deviation: 16-28%) were obtained. The obtained Cu NPs were applied to a nanofluid, which showed higher thermal conductivity than the theoretical value. The antibacterial activity of Cu NPs was also demonstrated, and found to have strong antibacterial activity.

Ultra-small Pd clusters supported by chitin nanowires as highly efficient catalysts

For the first time, chitin microspheres woven from nanowires with multi-scale porous structures were used as an excellent support for a catalyst of ultra-small Pd clusters. The Pd species anchored on the precursor Pre-Pd@chitin were 0.6 nm in average size, while the reduced catalyst Red-Pd@chitin featured ultra-small particles of 1.3 nm in average size. X-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM) demonstrated that the Pd catalyst in both oxidative and reductive states retained good dispersity and ultra-small clusters. The catalyst was tested for the hydrogenation of p-nitroanisole, exhibiting an excellent initial rate (13× that of commercial Pd/C)and excellent turnover frequency reaching 52,000 h−1. Furthermore, the catalyst could be recycled and used more than 10 times with no decay of the catalytic activity, suggesting potential industrial applications.

Biomimetic synthesis of silver nanoparticles using flower extract of Bauhinia purpurea and its antibacterial activity against clinical pathogens.

In the present study, we have reported an eco-friendly, rapid, and simple method for the synthesis of silver nanoparticles (AgNPs) using Bauhinia purpurea flower extract as non-toxic bioreducing agent. The formation of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The synthesized AgNPs were spherical in shape with an average size of 20nm. Furthermore, the antibacterial activities of the synthesized AgNPs (2-10mM) against clinical pathogens, Klebsiella sp. and Staphylococcus sp., were evaluated under in vitro conditions.

Fabrication and Characterization of Nano-Sized ZnSe Powders by Hydrothermal Process

Nano-sized Zinc selenide (ZnSe) powder was successfully synthesized using Zn and Se precursors in a hydrothermal process. Temperature for the synthesis was varied from 95 oC to 180 oC to evaluate its influence on the microstructural properties of the synthetic particles. ZnSe powder thus fabricated was characterized using various analytical tools such as SEM, XRD, TEM and UV-Vis methods. Two types of ZnSe particles, that is, the precipitated particle and the colloidal particles, were identified in the analysis. The precipitated particles were around 100 nm in average size, whereas the average size of the colloidal particles was around 20 nm. The precipitated particles made at 150 oC and 180 oC were found to be a single phase of ZnSe; however, an inhomogeneous phase was obtained at the lower synthesis temperature of 95 oC, suggesting that the temperature for the synthesis should be over 100 oC. The precipitated particles were inactive in the UV-Vis absorption investigation, whereas the colloidal particles showed that absorptions occurred at 380 nm in the UV-Vis spectrum.

Water Adsorption Property of Hierarchically Nanoporous Detonation Nanodiamonds.

The detonation nanodiamonds form the aggregate having interparticle voids, giving a marked hygroscopic property. As the relationship between pore structure and water adsorption of aggregated nanodiamonds is not well understood yet, adsorption isotherms of N2 at 77 K and of water vapor at 298 K of the well-characterized aggregated nanodiamonds were measured. HR-TEM and X-ray diffraction showed that the nanodiamonds were highly crystalline and their average crystallite size was 4.5 nm. The presence of the graphitic layers on the nanodiamond particle surface was confirmed by the EELS examination. The pore size distribution analysis showed that nanodiamonds had a few ultramicropores with predominant mesopores of 4.5 nm in average size. The water vapor adsorption isotherm of IUPAC Type V indicates the hydrophobicity of the nanodiamond aggregates, with the presence of hydrophilic sites. Then the hygroscopic nature of nanodiamonds should be associated with the surface functionalities of the graphitic shell and the ultramicropores on the mesopore walls.

Statistical optimization of experimental parameters for synthesis of two efficient photocatalyst: erbium carbonate and erbium oxide nanoparticles

A statistical approach (i.e. Taguchi robust design) was used to optimize a precipitation process for controlled preparation of nano-sized erbium carbonate particles. The parameters considered were the concentrations of the cation and anion solutions, as well as the flow rate at which the cation solution was added to the anion solution (Fy) and the temperature at which the reaction took place (Temz). The products were characterized to assess the effects of the parameters on the properties of the product and the optimal product, i.e. the product particles with the smallest size were then thermally treated to yield Er2O3 nanoparticles, which were found to be about 36 nm in average size. The morphology and chemical composition of both nano-structures were evaluated by X-ray diffraction, scanning electron microscopy, FT-IR and UV–Vis spectroscopies. Samples of both particles were tested as photodegradation catalysts for removing methyl orange under ultraviolet light.

Ethylenediaminetetraacetic acid capped superparamagnetic iron oxide (Fe3O4) nanoparticles: A novel preparation method and characterization

A novel and facile strategy is introduced for the preparation of ethylenediaminetetraacetic acid (EDTA) capped magnetite nanoparticles (MNPs). In this strategy, Fe3O4 nanoparticles were electrodeposited from a deposition bath containing 0.005M Fe2+/Fe3+ nitrate and chlorides alts and 1g/L EDTA. A simple deposition mode i.e. constant current and two-electrode set-up was used in the electro-synthesis procedure. The magnetite phase of the deposited nanoparticles was confirmed through XRD and FT-IR analyses. Morphological observations through FE-SEM and TEM confirmed the formation of spherical MNP particles with an average size of 10nm. The EDTA layer on the surface of the electro-synthesized magnetite nanoparticles was proved based on FT-IR, DLS and TG data. Vibrating sample magnetometer (VSM) measurements confirmed the EDTA capped iron oxide nanoparticles to have a super-paramagnetic nature, since they exhibit a high saturation magnetization (Ms=51.9emug−1), as well as, negligible remnant magnetization (Mr=0.59emug−1) and coercivity (Hc=0.85Oe). Based on the obtained results, the proposed platform can be considered as a fast, simple and efficient method for the preparation of the EDTA capped magnetite nanoparticles.