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1.
Small ; 20(27): e2312145, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38342591

RESUMEN

GeTe-based materials exhibit superior thermoelectric performance, while the development of power generation devices has mainly been limited by the challenge of designing the interface due to the phase transition in GeTe. In this work, via utilizing the low-temperature nano-Ag sintering technique and screening suitable Ti-Al alloys, a reliable interface with excellent connection performance has been realized. The Ti-Al intermetallic compounds effectively inhibit the diffusion process at Ti-34Al/Ge0.9Sb0.1Te interface. Thus, the thickness of the interfacial reaction layer only increases by ≈2.08 µm, and the interfacial electrical contact resistivity remains as low as ≈15.2 µΩ cm2 even after 30 days of isothermal aging at 773 K. A high conversion efficiency of ≈11.3% has been achieved in the GeTe/PbTe module at a hot-side temperature of 773 K and a cold-side temperature of 300 K. More importantly, the module's performance and the reliability of the interface remain consistently stable throughout 50 thermal cycles and long-term aging. This work promotes the application of high-performance GeTe materials for thermoelectric power generation.

2.
Int J Mol Sci ; 21(5)2020 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-32120830

RESUMEN

Nano Ag has excellent antibacterial properties and is widely used in various antibacterial materials, such as antibacterial medicine and medical devices, food packaging materials and antibacterial textiles. Despite the many benefits of nano-Ag, more and more research indicates that it may have potential biotoxic effects. Studies have shown that people who ingest nanoparticles by mouth have the highest uptake in the intestinal tract, and that the colon area is the most vulnerable to damage and causes the disease. In this study, we examined the toxic effects of different concentrations of Ag-NPs on normal human colon cells (NCM460) and human colon cancer cells (HCT116). As the concentration of nanoparticles increased, the activity of the two colon cells decreased and intracellular reactive oxygen species (ROS) increased. RT-qPCR and Western-blot analyses showed that Ag NPs can promote the increase in P38 protein phosphorylation levels in two colon cells and promote the expression of P53 and Bax. The analysis also showed that Ag NPs can promote the down-regulation of Bcl-2, leading to an increased Bax / Bcl-2 ratio and activation of P21, further accelerating cell death .This study showed that a low concentration of nano Ag has no obvious toxic effect on colon cells, while nano Ag with concentrations higher than 15 µg/mL will cause oxidative damage to colon cells.


Asunto(s)
Antibacterianos/toxicidad , Daño del ADN/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Nanopartículas del Metal/química , Estrés Oxidativo/efectos de los fármacos , Plata/toxicidad , Antibacterianos/farmacología , Supervivencia Celular/efectos de los fármacos , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Daño del ADN/genética , Células Epiteliales/citología , Células HCT116 , Humanos , Nanopartículas del Metal/ultraestructura , Microscopía Electrónica de Transmisión , Estrés Oxidativo/genética , Fosforilación , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Plata/farmacología , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
3.
J Environ Sci (China) ; 89: 180-193, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31892390

RESUMEN

Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials, and thus, the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag+ ratios. Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays, and shifts to both Ag particles and released Ag+ in 48 hr bioassays. Herein, as a continued study, the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically. The cytotoxicity and mechanisms of nano-Ag colloids are dynamic throughout exposure and are derived from both Ag ions and particles. Ag accumulation by E. coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure, and thereafter mainly from intracellular Ag ions. Fe3+ accelerates the oxidative dissolution of nano-Ag colloids, which results in decreasing amounts of Ag particles and particle-related toxicity. Na+ stabilizes nano-Ag colloids, thereby decreasing the bioavailability of Ag particles and particle-related toxicity. Humic acid (HA) binds Ag+ to form Ag+-HA, decreasing ion-related toxicity and binding to the E. coli surface, decreasing particle-related toxicity. HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na+ or Fe3+. The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors, and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.


Asunto(s)
Escherichia coli/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Plata/toxicidad , Coloides , Escherichia coli/metabolismo , Hierro/química , Concentración Osmolar , Plata/metabolismo
4.
Molecules ; 22(7)2017 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-28703753

RESUMEN

Polylactide (PLA)/nano-TiO2 and PLA/nano-TiO2/nano-Ag blends films were prepared by a solvent volatilization method. Compared to pure PLA film, the nano-blend films have low water vapor permeability (WVP) and a poor transparency. With the increase of the NPs in the PLA, the tensile strength (TS) and elastic modulus (EM) decreased, while the elongation at break (ε) increased. SEM analysis indicated a rougher cross-section of the nano-blend films. According to the FTIR analysis, no new chemical bonds were formed in the nano-blend films. By using DSC to examine the crystallization and melting behavior, the result shows that the NPs have no effect on the glass transition (Tg) and melting temperature (Tm), but they caused an increase on the cold crystallization (Tc) and crystallinity (Xc). TGA results show that the addition of nanoparticles significantly improved the thermal stability. The PLA nano-blend films show a good antimicrobial activity against. E. coli and Listeria monocytogenes. Most important, we carried out migration tests, and verified that the release of NPs from the nano-blend films was within the standard limits.


Asunto(s)
Nanopartículas del Metal/química , Poliésteres/química , Embalaje de Productos , Titanio/química , Escherichia coli/efectos de los fármacos , Escherichia coli/patogenicidad , Humanos , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/patogenicidad , Poliésteres/farmacología , Vapor , Resistencia a la Tracción/efectos de los fármacos , Titanio/farmacología
5.
Molecules ; 22(3)2017 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-28327535

RESUMEN

The effects of poly(lactic acid) (PLA)-based film with inorganic antimicrobial nano-TiO2 and nano-Ag on the physicochemical and microbial quality of Tremella aurantialba stored at 4 ± 1 °C for 16 days was investigated. Rosemary essential oil (REO, 9 wt %) was added into PLA film as plasticizer. Low-density polyethylene (LDPE) and PLA film was used as the controls. The experiment measured physicochemical properties and microbial levels, such as weight loss, firmness, vitamin C, color, microbiological quality, and sensory quality. Although Tremella aurantialba packed by nano-composite films had the highest weight loss (4.96% and 5.17%) at the end of storage, it was still in the vicinity of 5%. Tremella aurantialba packed with nano-composite films were significantly (p < 0.05) firmer than those packed by LDPE, PLA, and PLA/REO films. The nano-composite films were more effective in reducing vitamin C and microbial counts and preserving the color of Tremella aurantialba than the other three groups. The overall acceptability of Tremella aurantialba packed by the nano-composite films still remained good and within the limits of marketability after 12 days of storage. The results suggested that the proposed nano-composite films could maintain the quality of Tremella aurantialba and extend its postharvest life.


Asunto(s)
Basidiomycota/química , Embalaje de Alimentos , Calidad de los Alimentos
6.
Chemistry ; 21(27): 9671-5, 2015 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-26061749

RESUMEN

An efficient, photocatalytic chlorination of alkylarene α-H groups using NaCl/HCl as a chlorine source has been developed, which involves a radical mechanism under visible-light (including sunlight) conditions. A chlorine radical is proposed to be formed by an electron transfer from chloride ion to O2 in air through the bandgap hole of the semiconductor AgCl. The chlorination protocol is characterized by its use of natural sunlight or other visible light, mild conditions, cheap source of chlorine, green solvent, and high selectivity. The yield of benzylchloride is 95% with a toluene conversion as high as 40%, which rivals traditional chlorination methods.

7.
Environ Sci Pollut Res Int ; 31(1): 191-214, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38049687

RESUMEN

Nano silver (Ag) was metallic Ag monomers with particle size to the nanoscale. Photocatalyst was a kind of semiconductor material with photocatalytic function. Loading precious metal Ag onto semiconductor surfaces by microwave, laser-induced, solvent-thermal and hydrothermal methods could capture photogenerated electrons, reduced the compounding rate of holes and photogenerated electrons during the photocatalytic process, thereby improving the electron transfer efficiency of photocatalysis and enhancing the absorption of visible light by silver nanoparticles through the plasma resonance effect. The highly reactive free radicals produced by photocatalysts were used in the organic degradation process to degrade organic matter into inorganic matter and was a faster, more efficient and less polluting method of pollutant degradation, which has attracted a lot of attention from researchers. This review discussed the modification of various types of photocatalysts by nano Ag through different methods. The photocatalytic degradation of dyes, antibiotics and persistent organic pollutants by different modified composites was also analyzed. This review covered the several ways and means in which nano Ag has modified diverse photocatalytic materials as well as the photocatalytic degradation of dyes, antibiotics and persistent organic pollutants. This review identified the drawbacks of the existing nano Ag-modified photocatalytic materials, including their low yield and lack of recyclability, and it also offered suggestions for potential future directions for their improvement. The purpose of this review was to further research on the technology of nano Ag-modified photocatalytic materials and to encourage the creation of new modified photocatalytic nanomaterials for the treatment of organic pollutant degradation.


Asunto(s)
Contaminantes Ambientales , Nanopartículas del Metal , Plata , Contaminantes Orgánicos Persistentes , Antibacterianos , Luz , Colorantes , Catálisis
8.
Artif Cells Nanomed Biotechnol ; 51(1): 441-452, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37594201

RESUMEN

High translucent zirconia (HTZ) has excellent mechanical properties, biocompatibility, and good semi-translucency making it an ideal material for aesthetic anterior dental implant abutments without antibacterial properties. In the oral environment, the surface of the abutment material is susceptible to microbial adhesion and biofilm formation, which can lead to infection or peri-implantitis and even implant failure. This study aims to promote the formation of a biological seal at the implant-soft tissue interface by modifying the HTZ surface, using the load-bearing capacity of the aluminosilicate porous structure and the broad-spectrum antibacterial effect of silver nanoparticles to prevent peri-implant bacterial infection and inflammation and to improve the success rate and prolong the use of the implant. FE-SEM (field emission scanning electron microscopes), EDS (energy dispersive spectroscopy), and XPS (X-ray photoelectron spectroscopy) results showed that aluminosilicate non-vacuum sintering can form open micro- and nanoporous structures on HTZ surfaces, and that porous aluminosilicate coatings obtain a larger number, smaller size, and more uniformly shaped silver nanoparticles than smooth aluminosilicate coatings, and could be deposited deeper in the coating. The ICP-AES (inductively coupled plasma-atomic emission spectroscopy) results showed that the early silver ion release of both the smooth silver coating and the porous silver coating was obvious, the silver ion concentration released by the former was higher than that of the latter. However, the silver ion concentration released by the porous silver coating was higher than that of the smooth coating when the release slowed down. Both smooth and porous silver coatings both inhibited E. coli (Escherichia coli), S. aureus (Staphylococcus aureus), and L. acidophilus (L. acidophilus), and porous silver coatings had stronger antibacterial properties. The silver coating was successfully constructed on the surface of HTZ, through aluminium silicate sintering and silver nitrate solution impregnation. It was found that the high concentration environment of silver nitrate solution was more advantageous for nano-Ag deposition, and the non-vacuum sintered porous surface was able to obtain a larger number of nano-Ag particles with smaller sizes. The porous Ag coating exhibited superior antibacterial properties. It was suggested that the HTZ with silver coating had clinical application, and good antibacterial properties that can improve the survival rate and service life of implants.


Asunto(s)
Escherichia coli , Nanopartículas del Metal , Plata/farmacología , Nitrato de Plata , Staphylococcus aureus , Antibacterianos/farmacología
9.
Sci Total Environ ; 820: 153358, 2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35077800

RESUMEN

The effects of emerging contaminants micro/nanoplastics (MPs/NPs) and silver nanoparticles (Ag NPs) on health have attracted universal concern throughout the world. However, it is unclear on the combined effects of MPs/NPs and Ag NPs on the biogeochemistry cycle such as nitrogen transformation and functional microorganism in the soil. In the present study, we conducted a 45-day soil microcosm experiment with polystyrene (PS) MPs/NPs and Ag NPs to investigate their combined impact on nitrogen cycling and the bacterial community. The results showed that MPs or NPs exerted limited effects on nitrogen transformation in the soil. The combined effects of PS MPs/NPs and Ag NPs were mainly caused by the presence of Ag NPs. However, PS NPs alleviated the inhibition of anammox and denitrification induced by Ag NPs via upregulating anammox-related genes and elevating nitrate and nitrite reductase activities. PS MPs + Ag NPs treatment significantly reduced bacterial diversity. PS MPs/NPs + Ag NPs increased the relative abundances of denitrifying Cupriavidus by 0.32% and 0.06% but decreased nitrogen-fixing functional microorganisms of Microvirga (by 2.05% and 2.24%), Bacillus (by 0.16% and 0.22%), and Herbaspirillum (by 0.14% and 0.07%) at the genus level compared with Ag NPs alone. The significant downregulation of nitrogen-fixing genes (K02586, K02588, and K02591) was observed in PS MPs/NPs + Ag NPs treatment compared to Ag NPs in the nitrogen metabolism pathway. Moreover, g-Lysobacter and g-Aquimonas were identified as biomarkers in PS MPs + Ag NPs and PS NPs + Ag NPs by LEfSe analysis. Our study sheds the light that changes of functional microorganism abundances contributed to the alteration of nitrogen transformation. Taking the particle size of plastics into account will be helpful to accurately assess the combined ecological risks of plastics and nanomaterial contaminants.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Nanopartículas del Metal/toxicidad , Nitrógeno , Poliestirenos , Plata/toxicidad , Suelo
10.
Materials (Basel) ; 15(17)2022 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-36079207

RESUMEN

The application of nano-Ag grains as antiviral and antibacterial materials is widely known since ancient times. The problem is the toxicity of the bulk or big-size grain materials. It is known that nano-sized silver grains affect human and animal cells in some medical treatments. The aim of this study is to investigate the influence of nano-Ag grains embedded in a carbonaceous matrix on cytotoxicity, genotoxicity in fibroblasts, and mutagenicity. The nanocomposite film is composed of silver nanograins embedded in a carbonaceous matrix and it was obtained via the PVD method by deposition from two separated sources of fullerenes and silver acetate powders. This method allows for the preparation of material in the form of a film or powder, in which Ag nanograins are stabilized by a carbon network. The structure and morphology of this material were studied using SEM/EDX, XRD, and Raman spectroscopy. The toxicology studies were performed for various types of the material differing in the size of Ag nanograins. Furthermore, it was found that these properties, such as cell viability, genotoxicity, and mutagenicity, depend on Ag grain size.

11.
Polymers (Basel) ; 14(16)2022 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-36015562

RESUMEN

Bacterial cellulose (BC) is naturally degradable, highly biocompatible, hydrophilic, and essentially non-toxic, making it potentially useful as a base for creating more sophisticated bio-based materials. BC is similar to plant-derived cellulose in terms of chemical composition and structure but has a number of important differences in microstructure that could provide some unique opportunities for use as a scaffold for other functions. In this study, bacterial cellulose was alkylated and then esterified to produce a carboxymethyl bacterial cellulose (CMBC) that was then used to produce six different composite films with potential antibacterial properties. The films were assessed for antibacterial activity against Staphylococcus aureus and Escherichia coli, pyrolysis characteristics using thermogravimetric analysis (TGA), microstructure using scanning electron microscopy (SEM), and mechanical properties. The addition of nano-silver (nano-Ag) markedly improved the antimicrobial activity of the films while also enhancing the physical and mechanical properties. The results indicate that the three-dimensional reticulated structure of the bacterial cellulose provides an excellent substrate for scaffolding other bioactive materials. Thus, the nano-BC was added into the CMBC/nano-Ag composites furthermore, and then the antibacterial and mechanical properties were improved 44% for E. coli, 59% for S. aureus, and 20% for tensile strength, respectively.

12.
Polymers (Basel) ; 15(1)2022 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-36616464

RESUMEN

Biomass energy has attracted widespread attention due to its renewable, storage, huge production and clean and pollution-free advantages. Using Robinia pseudoacacia bark (RPB) as raw material, biogas and bio-oil produced by pyrolysis of RPB were detected and analyzed by TG-DTG, TG-FTIR and PY-GC-MS under the action of nanocatalysis. TG results showed that CH4 and CO flammable gases were produced by pyrolysis. PY-GC-MS results showed that RPB was rapidly pyrolyzed to obtain alcohols, ketones, aldehydes and acids bio-oil. The content of phenolic substances was the highest, accounting for 32.18% of all substances.Nanocatalysis has a certain effect on RPB, accelerating the precipitation of pyrolysis products and improving the over-oxidation of bio-oil. In addition, the extracts of RPB were identified and analyzed by FTIR, NMR, GC-MS and LC-Q-TOF-MS, and more than 100 active ingredients, such as Betaine, Epicathin and ß-sitosterol, were detected. Their applications as additive energy in other fields were explored. Therefore, Robinia pseudoacacia bark constitutes a fine biofeedstock for biofuels and biochemicals.

13.
J Food Sci ; 86(6): 2481-2490, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33948960

RESUMEN

The migration study of nano-Ag migration from polylactic acid (PLA) films was studied. Samples treated by high-pressure food processing (0, 100, 200, 300, and 400 MPa pressure) were soaked in acetic acid solution and incubated at 20 °C for 90 days. At the end of storage, nano-Ag particles (AgNPs) migration from the PLA/AgNPs composite film treated under 200 MPa high pressure was the lowest. However, AgNPs migration was accelerated under 400 MPa high pressure. High-pressure processing (200 MPa) could cause denser structure and higher crystallinity degree in films than other treatments. Lower amount of AgNPs induced a decline in the intensity of specific characteristic peaks. The diffraction peak intensity of α-crystal for the film sample treated with 400 MPa was the lowest on day 60. The crystallization index of the PLA matrix changed with different high-pressure processing. The result indicated that appropriate high-pressure food processing could effectively suppress AgNPs migration from PLA-based film while contacting with acidic acid food simulant. PRACTICAL APPLICATION: The release of nanoparticles from food packaging material is a very important matter when the migration is concerned with regulatory and toxicity issues. The study described the migration kinetic of AgNPs from PLA nanocomposite film into acidic food simulant after different high-pressure food processing. The results indicated that the PLA/AgNPs nanocomposite film was safe for acidic food after high-pressure treatment.


Asunto(s)
Ácidos/análisis , Contaminación de Alimentos/análisis , Manipulación de Alimentos/métodos , Nanocompuestos/química , Poliésteres/química , Presión , Plata/fisiología , Ácidos/química , Cinética , Plata/química
14.
J Hazard Mater ; 414: 125480, 2021 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-33647610

RESUMEN

Integration of photovoltaic (PV) power generation and energy storage has been widely believed to be the ultimate solution for future energy demands. Herein, an ingenious method was reported to make full use of photovoltaic silicon cutting waste (SiCW) natural characters fabricating PSi@SiOx/Nano-Ag composite as anode material for high-performance lithium-ion batteries. The sheet-like structure with nano/micropores and native SiOx layer addressed the volume expansion issues of Si material. Ag nanoparticles greatly enhanced electrical conductivity of composite and promoted Li+/e- transport. Synergistic effect of the designed PSi@SiOx/Nano-Ag composite contributed outstanding cyclic performance with reversible capacity of 1409mAhg-1 after 500 cycles. Notably, full LIBs with PSi@SiOx/Nano-Ag anode and commercial Li[Ni0.6Co0.2Mn0.2]O2 (NCM622) cathode delivered stable capacity of 137.5mAhg-1 at current density of 200 mA g-1, accompanying with a high energy density of 438 Wh kg-1. Furthermore, electrochemical Li+ storage behavior of this PSi@SiOx/Nano-Ag electrode was studied, and reaction mechanism and crystal structure evolution during cycles were also revealed by in-situ XRD analysis. The synthesis method is facile and cost-effective, which paves a novel way towards high-performance Si-based anodes and promising markets for both solar photovoltaic and lithium-ion battery industries.

16.
Mater Sci Eng C Mater Biol Appl ; 109: 110402, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32228911

RESUMEN

Early diagnosis is the key to the good prognosis of breast cancer. At present, clinical tumor diagnosis is mainly through serum analysis, which is painful and can only detect relatively advanced tumors that have already metastasized from the glands into the blood circulation. Here, we developed an earlier diagnostic method (before tumor cells entering the blood) of breast cancers through a convenient and painless process with blood-free samples. The microneedles were utilized to insert into the animals' testing areas, while the tissue fluid was collected through our synthesized breathable thin film. The obtained tissue fluid sample was then incubated to form blue products. In the area where tumors occurred, the blue changes were more obvious than the healthy area, a semi-localization and semi-quantitative detection of the tumorous area thus could be realized. The results of corresponding animal experiments showed that, after the injection of tumor cells, the proposed nano-Ag based colorimetric method can detect the occurrence of breast cancers in 7 days. What is more, these early tumors could be effectively suppressed through classical DOX treatment. For comparison, the classical blood test needed 14 days to validate the occurrence of breast cancers. The subsequent human tests further demonstrated the feasibility of the present method. The development of this work could provide a more convenient, accurate and comfortable technology to support for the early screening and diagnosis of cancer patients, so as to fundamentally reduce the mortality of the breast cancers.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Nanopartículas del Metal/química , Nanocompuestos/química , Plata/química , Animales , Colorimetría , Femenino , Humanos , Inmunoensayo , Ratas , Ratas Sprague-Dawley , Vapor
17.
Nanomaterials (Basel) ; 10(6)2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32492894

RESUMEN

Using the electrical spark discharge method, this study prepared a nano-Ag colloid using self-developed, microelectrical discharge machining equipment. Requiring no additional surfactant, the approach in question can be used at the ambient temperature and pressure. Moreover, this novel physical method of preparation produced no chemical pollution. This study conducted an in-depth investigation to establish the following electrical discharge conditions: gap electrical discharge, short circuits, and open circuits. Short circuits affect system lifespan and cause electrode consumption, resulting in large, non-nanoscale particles. Accordingly, in this study, research for and design of a new logic judgment circuit set was used to determine the short-circuit rate. The Ziegler-Nichols proportional-integral-derivative (PID) method was then adopted to find optimal PID values for reducing the ratio between short-circuit and discharge rates of the system. The particle size, zeta potential, and ultraviolet spectrum of the nano-Ag colloid prepared using the aforementioned method were also analyzed with nanoanalysis equipment. Lastly, the characteristics of nanosized particles were analyzed with a transmission electron microscope. This study found that the lowest ratio between short-circuit rates was obtained (1.77%) when PID parameters were such that Kp was 0.96, Ki was 5.760576, and Kd was 0.039996. For the nano-Ag colloid prepared using the aforementioned PID parameters, the particle size was 3.409 nm, zeta potential was approximately -46.8 mV, absorbance was approximately 0.26, and surface plasmon resonance was 390 nm. Therefore, this study demonstrated that reducing the short-circuit rate can substantially enhance the effectiveness of the preparation and produce an optimal nano-Ag colloid.

18.
Nanomaterials (Basel) ; 9(9)2019 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-31462001

RESUMEN

Hydra magnipapillata cells reduce the toxicity of silver nanomaterials to zebrafish (Danio rerio) embryos. In this study, we investigated whether Hydra protein (HP) and Hydra basal disc peptide (Hym176) materials reduce nano-Ag-polyvinylpyrrolidone (N-Ag-PVP) toxicity during embryogenesis of the nanosensitive organism zebrafish. Protein (HP) was extracted from Hydra, and peptide (Hym176) was extracted from the hydra basal disc, which is attractive to nanomaterials and related to the immune system. The experimental conditions were exposure to N-Ag-PVP, HP, N-Ag-PVP+HP, Hym176, or N-Ag-PVP+Hym176 during embryo development. N-Ag-PVP+HP group showed lower toxicity than N-Ag-PVP group. In addition, in the N-Ag-PVP+HP group formed aggregated nanomaterials (≥200 nm size) through electrostatic bonding. In the gene expression profile, HP group differed in gene expression profile compared the other experimental groups and it was no genetic toxicity. HP showed a tendency to reduce side effects and abnormal gene expression produced by N-Ag-PVP with no evidence of inherent toxicity. Considering the potential nanotoxicity effects of released nanomaterials on the ecosystem, the reduction of nanotoxicity observed with HP natural materials should be regarded with great interest in terms of the overall health of the ecosystem.

19.
Polymers (Basel) ; 10(8)2018 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-30960818

RESUMEN

Different percentages (0%, 1%, 5%, and 10%) of nano-Ag particles were added to polylactic acid (PLA) to make an active nanocomposite packaging film. Strawberries were packaged by the nanocomposite films and stored at 4 ± 1 °C for 10 days. The freshness of strawberries was assessed by regularly measuring the physicochemical properties of the strawberries in each packaging film. The difference in the freshness of strawberries was evaluated by determining the following parameter changes: weight loss, hardness, soluble solids, titratable acid, color, vitamin C, total phenol, free radical scavenging activity, peroxidase activity, and sensory evaluation. The results revealed that the active nanocomposite packaging film has better preservation effect when compared with pure PLA film. Its preservation effect is mainly reflected in the more effective reduction of vitamin C loss, delaying the decline of total phenols and 1-Diphenyl-2-picrylhydrazyl (DPPH) in strawberries. It also showed better physical properties. The results showed that the PLA nanocomposite packaging film could effectively preserve freshness of strawberries.

20.
Environ Pollut ; 243(Pt A): 17-27, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30170204

RESUMEN

Most existing models for assessing the releases of engineered nanomaterials (ENMs) into the environment are based on the assumption that ENMs remain in their pristine forms during their whole life cycle. It is known, however, that this is not always the case as ENMs are often embedded into solid matrices during manufacturing and can undergo physical or chemical transformations during their life cycle, e.g. upon release to wastewater. In this work, we present a method for systematically assessing the forms in which nano-Ag and nano-TiO2 flow through their life cycle (i.e. production, manufacturing, use and disposal) to their points of release to air, soil and surface water. Input data on the forms of released ENMs were probability distributions based on peer-reviewed literature. Release data were incorporated into a probabilistic material flow analysis model to quantify the proportions of ENMs in product-embedded, matrix-embedded, pristine, transformed and dissolved forms in all technical and environmental compartments into which they flow, at the European scale. Releases of nano-Ag to surface water and soil were modelled to occur primarily in transformed forms (Q25 and Q75 of 34-58% and 78-86%, respectively, with means of 53% and 82%), while releases to air were mostly in pristine and matrix-embedded forms (38-46% and 36-44%, respectively, with means of 42% and 40%). In contrast, nano-TiO2 releases to air, soil and water were estimated to be predominantly in pristine form (75-85%, 90-95%, 96-98%, respectively, with means of 80%, 91% and 97%). The distributions of ENM releases between forms developed here will improve the representativeness and appropriateness of input data for environmental fate modelling and risk assessment of ENMs.


Asunto(s)
Aire/análisis , Modelos Estadísticos , Nanoestructuras/análisis , Plata/análisis , Suelo/química , Titanio/análisis , Agua/química , Medición de Riesgo
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