Displaying publications 1 - 20 of 365 in total

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  1. Kesan penambahan nano Ag terhadap suhu genting dan pembentukan fasa superkonduktor (Tl0.85Cr0.15)Sr2CaCu2O7-δ
    Kong W, Koh A, Abd-Shukor R
    Sains Malaysiana, 2009;38.
    Superkonduktor suhu tinggi berasaskan sistem (Tl0.85Cr0.15)Sr2CaCu2O7-Agx (Tl1212) dengan komposisi x = 0.0, 0.01, 0.02, 0.03 dan 0.05 telah disediakan dengan kaedah tindak balas keadaan pepejal. Rintangan elektrik terhadap suhu telah diukur dengan kaedah penduga empat titik. Suhu genting mula, Tc-mula bagi sistem Tl1212 tanpa penambahan nano Ag adalah 113 K. Penambahan nano Ag menurunkan suhu genting sampel. Corak pembelauan sinar-X menunjukkan bahawa semua sampel mempunyai fasa dominan 1212. Sampel x = 0.02 mempunyai peratusan fasa 1212 yang tertinggi iaitu 87%.
    Matched MeSH terms: Silver
  2. Fulltext Trophic transfer of silver nanoparticles shifts metabolism in snails and reduces food safety
    Dang F, Li C, Nunes LM, Tang R, Wang J, Dong S, et al.
    Environ Int, 2023 Jun;176:107990.
    PMID: 37247467 DOI: 10.1016/j.envint.2023.107990
    Food security and sustainable development of agriculture has been a key challenge for decades. To support this, nanotechnology in the agricultural sectors increases productivity and food security, while leaving complex environmental negative impacts including pollution of the human food chains by nanoparticles. Here we model the effects of silver nanoparticles (Ag-NPs) in a food chain consisting of soil-grown lettuce Lactuca sativa and snail Achatina fulica. Soil-grown lettuce were exposed to sulfurized Ag-NPs via root or metallic Ag-NPs via leaves before fed to snails. We discover an important biomagnification of silver in snails sourced from plant root uptake, with trophic transfer factors of 2.0-5.9 in soft tissues. NPs shifts from original size (55-68 nm) toward much smaller size (17-26 nm) in snails. Trophic transfer of Ag-NPs reprograms the global metabolic profile by down-regulating or up-regulating metabolites for up to 0.25- or 4.20- fold, respectively, relative to the control. These metabolites control osmoregulation, phospholipid, energy, and amino acid metabolism in snails, reflecting molecular pathways of biomagnification and pontential adverse biological effects on lower trophic levels. Consumption of these Ag-NP contaminated snails causes non-carcinogenic effects on human health. Global public health risks decrease by 72% under foliar Ag-NP application in agriculture or through a reduction in the consumption of snails sourced from root application. The latter strategy is at the expense of domestic economic losses in food security of $177.3 and $58.3 million annually for countries such as Nigeria and Cameroon. Foliar Ag-NP application in nano-agriculture has lower hazard quotient risks on public health than root application to ensure global food safety, as brought forward by the United Nations Sustainable Development Goals.
    Matched MeSH terms: Silver/toxicity; Silver/chemistry
  3. Adducts of triangular silver(i) 3,5-bis(trifluoromethyl)pyrazolate with thiophene derivatives: a weak interaction model of desulfurization
    Liu R, Zhang W, Wei D, Chen JH, Ng SW, Yang G
    Dalton Trans, 2019 Nov 21;48(43):16162-16166.
    PMID: 31651001 DOI: 10.1039/c9dt03344k
    π-Acidic triangular silver(i) 3,5-bis(trifluoromethyl)pyrazolate (Ag3pz3) can form 1 : 1 adducts with dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), benzothiophene (BT), and 2,5-dimethylthiophene (DMT), which are stabilized by weak AgS and AgC contacts and sometimes by π-π stacking and, therefore, may represent a weak interaction model for some adsorptive desulfurization processes.
    Matched MeSH terms: Silver
  4. Bifunctional Z-Scheme Ag/AgVO3/g-C3N4 photocatalysts for expired ciprofloxacin degradation and hydrogen production from natural rainwater without using scavengers
    Samsudin MFR, Frebillot C, Kaddoury Y, Sufian S, Ong WJ
    J Environ Manage, 2020 Sep 15;270:110803.
    PMID: 32721291 DOI: 10.1016/j.jenvman.2020.110803
    To maximize the employment of sustainable solar energy in treating the recalcitrant pollutant and hydrogen energy production, the development of a highly efficient photocatalyst is desirable. Herein, a Z-scheme Ag/AgVO3/g-C3N4 photocatalyst was synthesized via a wet-impregnation method. The amount of Ag/AgVO3 deposited onto g-C3N4 has a significant effect on the photocharge carrier separation and migration of the as-developed Z-scheme photocatalyst. It was found that 0.5 wt % Ag/AgVO3/g-C3N4 photocatalyst exhibited a profound photocatalytic degradation performance with 82.6% ciprofloxacin removal and 3.57 mmol/h of hydrogen produced from natural rainwater under visible-light irradiation. Additionally, the apparent quantum efficiency (AQE) of this sample was 9.95% at 420 nm which is four times higher than the pure sample. The remarkable photocatalytic performance was attributed to the enhanced crystallographic structure, evidently from the XRD and XPS analysis. Moreover, the intimate contact between Ag/AgVO3 and g-C3N4 nanoparticles allows the smooth photocharge carrier separation and migrations, resulting in superior photocatalytic performance in comparison to the pure samples. Interestingly, the profound photocatalytic activity demonstrated here was achieved without the addition of any sacrificial reagents. This work demonstrates the feasibility of utilizing visible-light-driven photocatalysts in treating the recalcitrant antibiotic pollutants and producing hydrogen from natural rainwater.
    Matched MeSH terms: Silver*
  5. Application of the kinetic and isotherm models for better understanding of the behaviors of silver nanoparticles adsorption onto different adsorbents
    Syafiuddin A, Salmiati S, Jonbi J, Fulazzaky MA
    J Environ Manage, 2018 Jul 15;218:59-70.
    PMID: 29665487 DOI: 10.1016/j.jenvman.2018.03.066
    It is the first time to do investigation the reliability and validity of thirty kinetic and isotherm models for describing the behaviors of adsorption of silver nanoparticles (AgNPs) onto different adsorbents. The purpose of this study is therefore to assess the most reliable models for the adsorption of AgNPs onto feasibility of an adsorbent. The fifteen kinetic models and fifteen isotherm models were used to test secondary data of AgNPs adsorption collected from the various data sources. The rankings of arithmetic mean were estimated based on the six statistical analysis methods of using a dedicated software of the MATLAB Optimization Toolbox with a least square curve fitting function. The use of fractal-like mixed 1, 2-order model for describing the adsorption kinetics and that of Fritz-Schlunder and Baudu models for describing the adsorption isotherms can be recommended as the most reliable models for AgNPs adsorption onto the natural and synthetic adsorbent materials. The application of thirty models have been identified for the adsorption of AgNPs to clarify the usefulness of both groups of the kinetic and isotherm equations in the rank order of the levels of accuracy, and this significantly contributes to understandability and usability of the proper models and makes to knowledge beyond the existing literatures.
    Matched MeSH terms: Silver*
  6. Efficacy of incorporating silver nanoparticles into maxillofacial silicone against Staphylococcus aureus, Candida albicans, and polymicrobial biofilms
    Chong WX, Lai YX, Choudhury M, Amalraj FD
    J Prosthet Dent, 2022 Nov;128(5):1114-1120.
    PMID: 33685653 DOI: 10.1016/j.prosdent.2021.01.010
    STATEMENT OF PROBLEM: The presence of biofilms on maxillofacial silicone increases the risk of infections and reduces durability. Whether silver nanoparticles (AgNPs) with potent antimicrobial effects help reduce biofilm formation is unclear.

    PURPOSE: The purpose of this in vitro study was to assess the antimicrobial effect of sub 10-nm AgNPs in maxillofacial silicone against Staphylococcus aureus, Candida albicans, and mixed species biofilms containing both and to test the effectiveness of different AgNP concentrations against all 3 biofilms in vitro.

    MATERIAL AND METHODS: Silicone disks (M511; Technovent Ltd) containing 0.0% (control), 0.1%, and 0.5% AgNPs were fabricated and treated with S. aureus, C. albicans, and mixed species strains of both in 24-well culture plates containing appropriate media. Each well received a 0.1-mL aliquot of the standardized suspension of microorganisms. The plates were incubated for 21 consecutive days, and colony-forming units per milliliter (CFU/mL) were measured on the first, third, fifth, seventh, fifteenth, and twenty-first day with the Miles and Misra method. Data were analyzed by 2-way ANOVA and the paired t test to evaluate the relationship between AgNP concentration, microbial strain, and time (α=.05). Mean CFU/mL differences for each time and for each biofilm category were assessed by repeated measure ANOVA.

    RESULTS: AgNPs decreased the mean CFU/mL in both concentrations compared with the control. The 0.1% concentration showed sustained efficacy throughout the test, while the 0.5% concentration had high efficacy initially with a gradual decrease. However, the results were inconsistent for the mixed biofilm. The paired sample t test at day 3 and 15 and day 3 and 21 showed statistically significantly different results (Psilver ion leaching, and cellular internalization. Mixed species biofilm needs further exploration with standardized study parameters.

    Matched MeSH terms: Silver/pharmacology
  7. An enzyme-free turn-on fluorescent strategy for nucleic acid detection based on hybridization chain reaction and transferable silver nanoclusters
    Wong ZW, New SY
    Mikrochim Acta, 2022 Dec 08;190(1):16.
    PMID: 36480078 DOI: 10.1007/s00604-022-05591-0
    A fluorescence biosensor has been developed based on hybridisation chain reaction (HCR) amplification coupled with silver nanoclusters (AgNCs) for nucleic acid detection. The fluorescence was activated via end-to-end transfer of dark AgNCs caged within a DNA template to another DNA sequence that could enhance their red fluorescence emission at 611 nm. Such cluster-transfer approach allows us to introduce fluorogenic AgNCs as external signal transducers, thereby enabling HCR to perform in a predictable manner. The resulted HCR-AgNC biosensor was able to detect target DNA with a detection limit of 3.35 fM, and distinguish the DNA target from single-base mismatch sequences. Moreover, the bright red fluorescence emission was detectable with the naked eye, with concentration of target DNA down to 1 pM. The biosensor also performed well in human serum samples with good recovery. Overall, our cluster-transfer approach provides a good alternative to construct HCR-AgNC assay with less risk of circuit leakage and produce AgNCs in a controllable manner.
    Matched MeSH terms: Silver*
  8. Fulltext Size-controlled and optical properties of monodispersed silver nanoparticles synthesized by the radiolytic reduction method
    Saion E, Gharibshahi E, Naghavi K
    Int J Mol Sci, 2013;14(4):7880-96.
    PMID: 23579953 DOI: 10.3390/ijms14047880
    Size-controlled and monodispersed silver nanoparticles were synthesized from an aqueous solution containing silver nitrate as a metal precursor, polyvinyl alcohol as a capping agent, isopropyl alcohol as hydrogen and hydroxyl radical scavengers, and deionized water as a solvent with a simple radiolytic method. The average particle size decreased with an increase in dose due to the domination of nucleation over ion association in the formation of the nanoparticles by gamma reduction. The silver nanoparticles exhibit a very sharp and strong absorption spectrum with the absorption maximum λmax blue shifting with an increased dose, owing to a decrease in particle size. The absorption spectra of silver nanoparticles of various particle sizes were also calculated using a quantum physics treatment and an agreement was obtained with the experimental absorption data. The results suggest that the absorption spectrum of silver nanoparticles possibly derived from the intra-band excitations of conduction electrons from the lowest energy state (n = 5, l = 0) to higher energy states (n ≥ 6; Δl = 0, ±1; Δs = 0, ±1), allowed by the quantum numbers principle. This demonstrates that the absorption phenomenon of metal nanoparticles based on a quantum physics description could be exploited to be added into the fundamentals of metal nanoparticles and the related fields of nanoscience and nanotechnology.
    Matched MeSH terms: Silver/chemistry*; Silver Nitrate/chemistry
  9. Fulltext Fabrication of silver nanoparticles dispersed in palm oil using laser ablation
    Zamiri R, Zakaria A, Ahangar HA, Sadrolhosseini AR, Mahdi MA
    Int J Mol Sci, 2010;11(11):4764-70.
    PMID: 21151470 DOI: 10.3390/ijms11114764
    In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.
    Matched MeSH terms: Silver/chemistry*
  10. Silver(I)-mediated base pairing in parallel-stranded DNA involving the luminescent cytosine analog 1,3-diaza-2-oxophenoxazine
    Schönrath I, Tsvetkov VB, Zatsepin TS, Aralov AV, Müller J
    J Biol Inorg Chem, 2019 08;24(5):693-702.
    PMID: 31263954 DOI: 10.1007/s00775-019-01682-1
    1,3-Diaza-2-oxophenoxazine (X) has been introduced as a ligand in silver(I)-mediated base pairing in a parallel DNA duplex. This fluorescent cytosine analog is capable of forming stabilizing X-Ag(I)-X and X-Ag(I)-C base pairs in DNA duplexes, as confirmed by temperature-dependent UV spectroscopy and luminescence spectroscopy. DFT calculations of the silver(I)-mediated base pairs suggest the presence of a synergistic hydrogen bond. Molecular dynamics (MD) simulations of entire DNA duplexes nicely underline the geometrical flexibility of these base pairs, with the synergistic hydrogen bond facing either the major or the minor groove. Upon silver(I) binding to the X:X or X:C base pairs, the luminescence emission maximum experiences a red shift from 448 to 460 nm upon excitation at 370 nm. Importantly, the luminescence of the 1,3-diaza-2-oxophenoxazine ligand is not quenched significantly upon binding a silver(I) ion. In fact, the luminescence intensity even increases upon formation of a X-Ag(I)-C base pair, which is expected to be beneficial for the development of biosensors. As a consequence, the silver(I)-mediated phenoxazinone base pairs represent the first strongly fluorescent metal-mediated base pairs.
    Matched MeSH terms: Silver/chemistry*
  11. Green synthesis, characterization and applications of silver nanoparticle mediated by the aqueous extract of red onion peel
    Tan Sian Hui Abdullah HS, Aqlili Riana Mohd Asseri SN, Khursyiah Wan Mohamad WN, Kan SY, Azmi AA, Yong Julius FS, et al.
    Environ Pollut, 2021 Feb 15;271:116295.
    PMID: 33383429 DOI: 10.1016/j.envpol.2020.116295
    This manuscript describes the reuse of biowaste for the biosynthesis of silver nanoparticles (AgNPs) and their applications. In particular, we hypothesized that the phytochemicals in the onion peels could act as reductant for silver nanoparticles syntheses. AgNO3 solution (1 mmol) was added dropwise to an aqueous solution of onion peel extract in 3:7 ratio. The reaction mixture was subjected to heating at 90 °C for about 30 min. During the synthesis of the AgNPs, the change of the colour of solution was observed. The AgNPs solution was centrifuged to obtain the two layers, which consists of clear solution and solid layers at 12000 rpm for 30 min. The precipitate was filtered and was re-dispersed in deionised water (25 mL). The solution was centrifuged again to obtain the purified AgNPs. Subsequently, this solution was freeze dried for 48 h to afford the powdered AgNPs. In this work, the structure of the AgNPs were synthesized in spherical shape, with an average size of 12.5 nm observed in the Transmission electron microscopy (TEM) analysis. For catalytic application, the synthesized AgNPs could be applied as green catalyst to promote Knoevenagel and Hantzsch reactions. In most cases, the desired products were obtained in satisfactory yields. In addition, the AgNPs were found to be recyclable for the subsequent reactions. After five successive runs, the average isolated yields for both transformations were recorded to be 91% (Knoevenagel condensation) and 94% (Hantzsch reaction), which indicated that the existing AgNPs could apply as green catalyst in the field of organic synthesis. Furthermore, the AgNPs also showed satisfactory result in antioxidant activity. The current results indicate that the AgNPs can act as alternative antioxidant agent and green catalyst in mediating organic transformations.
    Matched MeSH terms: Silver*
  12. A facile synthesis method of hydroxyethyl cellulose-silver nanoparticle scaffolds for skin tissue engineering applications
    Zulkifli FH, Hussain FSJ, Zeyohannes SS, Rasad MSBA, Yusuff MM
    Mater Sci Eng C Mater Biol Appl, 2017 Oct 01;79:151-160.
    PMID: 28629002 DOI: 10.1016/j.msec.2017.05.028
    Green porous and ecofriendly scaffolds have been considered as one of the potent candidates for tissue engineering substitutes. The objective of this study is to investigate the biocompatibility of hydroxyethyl cellulose (HEC)/silver nanoparticles (AgNPs), prepared by the green synthesis method as a potential host material for skin tissue applications. The substrates which contained varied concentrations of AgNO3(0.4%-1.6%) were formed in the presence of HEC, were dissolved in a single step in water. The presence of AgNPs was confirmed visually by the change of color from colorless to dark brown, and was fabricated via freeze-drying technique. The outcomes exhibited significant porosity of >80%, moderate degradation rate, and tremendous value of water absorption up to 1163% in all samples. These scaffolds of HEC/AgNPs were further characterized by SEM, UV-Vis, ATR-FTIR, TGA, and DSC. All scaffolds possessed open interconnected pore size in the range of 50-150μm. The characteristic peaks of Ag in the UV-Vis spectra (417-421nm) revealed the formation of AgNPs in the blend composite. ATR-FTIR curve showed new existing peak, which implies the oxidation of HEC in the cellulose derivatives. The DSC thermogram showed augmentation in Tgwith increased AgNO3concentration. Preliminary studies of cytotoxicity were carried out in vitro by implementation of the hFB cells on the scaffolds. The results substantiated low toxicity of HEC/AgNPs scaffolds, thus exhibiting an ideal characteristic in skin tissue engineering applications.
    Matched MeSH terms: Silver/chemistry*
  13. Characterization of natural gums via elemental and chemometric analyses, synthesis of silver nanoparticles, and biological and catalytic applications
    Jamila N, Khan N, Hwang IM, Saba M, Khan F, Amin F, et al.
    Int J Biol Macromol, 2020 Mar 15;147:853-866.
    PMID: 31739066 DOI: 10.1016/j.ijbiomac.2019.09.245
    Gums; composed of polysaccharides, carbohydrates, proteins, and minerals, are high molecular weight hydrophilic compounds with several biological applications. This study describes the nutritional and toxic elements content, chemical composition, synthesis of silver nanoparticles (G-AgNPs), and pharmacological and catalytic properties of Prunus armeniaca (apricot), Prunus domestica (plums), Prunus persica (peaches), Acacia modesta (phulai), Acacia arabica (kikar), and Salmalia malabarica (silk cotton tree) gums. The elemental contents were analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ICP-mass spectrometry (ICP-MS). NMR spectroscopy was used for the identification of class of compounds in the mixture, their functional groups were determined through FTIR techniques, and plasmon resonance and size of G-AgNPs through UV-Vis spectroscopic technique and transmission electron microscopy (TEM). From the results, nutritional elements were present at appreciable concentrations, whereas toxic elements showed content below the maximum permissible ranges. Using the elemental data, linear discriminant and principal component analyses classified the gums to 99.9% variability index. Furthermore, G-AgNPs exhibited significant antioxidant, antibacterial, and redox catalytic potential. Hence, the subject G-AgNPs could have promising nutritional, therapeutic and environmental remediation applications.
    Matched MeSH terms: Silver/chemistry*
  14. Hydrothermal synthesis and photocatalytic application of ZnS-Ag composites based on biomass-derived carbon aerogel for the visible light degradation of methylene blue
    Shanmugam P, Parasuraman B, Boonyuen S, Thangavelu P, AlSalhi MS, Zheng ALT, et al.
    Environ Geochem Health, 2024 Feb 17;46(3):92.
    PMID: 38367085 DOI: 10.1007/s10653-024-01871-1
    A facile and cost-effective hydrothermal followed by precipitation method is employed to synthesize visible light-driven ZnS-Ag ternary composites supported on carbon aerogel (CA). Extensive studies were conducted on the structural, morphological, and optical properties, confirming the successful formation of ternary nanocomposites. The obtained results evidently demonstrate the successful loading of ZnS and Ag onto the surface of the CA. High-resolution transmission electron microscopy analysis revealed that ZnS and Ag nanoparticles (AgNPs) were uniformly distributed on the surface of the CA with an average diameter of 18 nm. The biomass-derived CA, containing a hierarchical porous nano-architecture and an abundant number of -NH2 functional groups on the surface, can greatly prevent the agglomeration, stability and reduce particle size. Brunauer-Emmett-Teller analysis results indicated specific surface areas of 4.62 m2 g-1 for the CA, 48.50 m2 g-1 for the CA/ZnS composite, and 62.62 m2 g-1 for the CA/ZnS-Ag composite. These values demonstrate an increase in surface area upon the incorporation of ZnS and Ag into the CA matrix. Under visible light irradiation, the synthesized CA/ZnS-Ag composites displayed remarkably improved photodegradation efficiency of methylene blue (MB). Among the tested samples, the CA/ZnS-Ag composites exhibited the highest percentage of photodegradation efficiency, surpassing ZnS, CA, and CA/ZnS. The obtained percentages of degradation efficiency for CA, ZnS, CA/ZnS, and CA/ZnS-Ag composites were determined as 26.60%, 52.12%, 68.39%, and 98.64%, respectively. These results highlight the superior photocatalytic performance of the CA/ZnS-Ag composites in the degradation of MB under visible light conditions. The superior efficiency of the CA/ZnS-Ag composite can be attributed to multiple factors, including its elevated specific surface area, inhibition of electron-hole pair recombination, and enhanced photon absorption within the visible light spectrum. The CA/ZnS-Ag composites displayed consistent efficiency over multiple cycles, confirming their stable performance, reusability, and enduring durability, thereby showcasing the robust nature of this composite material.
    Matched MeSH terms: Silver/chemistry
  15. Is metal nanofluid reliable as heat carrier?
    Nine MJ, Chung H, Tanshen MR, Osman NA, Jeong H
    J Hazard Mater, 2014 May 30;273:183-91.
    PMID: 24735805 DOI: 10.1016/j.jhazmat.2014.03.055
    A pre- and post experimental analysis of copper-water and silver-water nanofluids are conducted to investigate minimal changes in quality of nanofluids before and after an effective heat transfer. A single loop oscillating heat pipe (OHP) having inner diameter of 2.4mm is charged with aforementioned nanofluids at 60% filling ratio for end to end heat transfer. Post experimental analysis of both nanofluids raises questions to the physical, chemical and thermal stability of such suspension for hazardless uses in the field of heat transfer. The color, deposition, dispersibility, propensity to be oxidized, disintegration, agglomeration and thermal conductivity of metal nanofluids are found to be strictly affected by heat transfer process and vice versa. Such degradation in quality of basic properties of metal nanofluids implies its challenges in practical application even for short-term heat transfer operations at oxidative environment as nano-sized metal particles are chemically more unstable than its bulk material. The use of the solid/liquid suspension containing metal nanoparticles in any heat exchanger as heat carrier might be detrimental to the whole system.
    Matched MeSH terms: Silver*
  16. Fulltext Green formation of spherical and dendritic silver nanostructures under microwave irradiation without reducing agent
    Noroozi M, Zakaria A, Moksin MM, Wahab ZA, Abedini A
    Int J Mol Sci, 2012;13(7):8086-96.
    PMID: 22942691 DOI: 10.3390/ijms13078086
    The rapid and green formation of spherical and dendritic silver nanostructures based on microwave irradiation time was investigated. Silver nanoparticles were successfully fabricated by reduction of Ag(+) in a water medium and using polyvinylpyrrolidone (PVP) as the stabilizing agent and without the use of any other reducing agent, and were compared with those synthesized by conventional heating method. UV-vis absorption spectrometry, transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and photon correlation spectroscopy (PCS) measurements, indicated that increasing the irradiation time enhanced the concentration of silver nanoparticles and slightly increased the particle size. There was a lack of large silver nanoparticles at a high concentration, but interestingly, the formation and growth of silver dendrite nanostructures appeared. Compared to conventional heating methods, the silver nanoparticle suspension produced by irradiated microwaves was more stable over a six-month period in aqueous solution without any signs of precipitation.
    Matched MeSH terms: Silver Nitrate/chemistry*
  17. Fulltext Green synthesis and characterization of silver/chitosan/polyethylene glycol nanocomposites without any reducing agent
    Ahmad MB, Tay MY, Shameli K, Hussein MZ, Lim JJ
    Int J Mol Sci, 2011;12(8):4872-84.
    PMID: 21954331 DOI: 10.3390/ijms12084872
    This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO(3) in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO(3)) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.
    Matched MeSH terms: Silver/chemistry*
  18. Fulltext Effect of accelerator in green synthesis of silver nanoparticles
    Darroudi M, Ahmad MB, Abdullah AH, Ibrahim NA, Shameli K
    Int J Mol Sci, 2010;11(10):3898-905.
    PMID: 21152307 DOI: 10.3390/ijms11103898
    Silver nanoparticles (Ag-NPs) were successfully synthesized in the natural polymeric matrix. Silver nitrate, gelatin, glucose, and sodium hydroxide have been used as silver precursor, stabilizer, reducing agent, and accelerator reagent, respectively. This study investigated the role of NaOH as the accelerator. The resultant products have been confirmed to be Ag-NPs using powder X-ray diffraction (PXRD), UV-vis spectroscopy, and transmission electron microscopy (TEM). The colloidal sols of Ag-NPs obtained at different volumes of NaOH show strong and different surface plasmon resonance (SPR) peaks, which can be explained from the TEM images of Ag-NPs and their particle size distribution. Compared with other synthetic methods, this work is green, rapid, and simple to use. The newly prepared Ag-NPs may have many potential applications in chemical and biological industries.
    Matched MeSH terms: Silver/chemistry*
  19. Adsorption of butyl acetate in air over silver-loaded Y and ZSM-5 zeolites: experimental and modelling studies
    Bhatia S, Abdullah AZ, Wong CT
    J Hazard Mater, 2009 Apr 15;163(1):73-81.
    PMID: 18649998 DOI: 10.1016/j.jhazmat.2008.06.055
    Adsorption behaviours of butyl acetate in air have been studied over silver-loaded Y (Si/Al=40) and ZSM-5 (Si/Al=140) zeolites. The silver metal was loaded into the zeolites by ion exchange (IE) and impregnation (IM) methods. The adsorption study was mainly conducted at a gas hourly space velocity (GHSV) of 13,000 h(-1) with the organic concentration of 1000 ppm while the desorption step was carried out at a GHSV of 5000 h(-1). The impregnated silver-loaded adsorbents showed lower uptake capacity and shorter breakthrough time by about 10 min, attributed to changes in the pore characteristics and available surface for adsorption. Silver exchanged Y (AgY(IE)) with lower hydrophobicity showed higher uptake capacity of up to 35%, longer adsorbent service time and easier desorption compared to AgZSM-5(IE). The presence of water vapour in the feed suppressed the butyl acetate adsorption of AgY(IE) by 42% due to the competitive adsorption of water on the surface and the effect was more pronounced at lower GHSV. Conversely, the adsorption capacity of AgZSM-5(IE) was minimally affected, attributed to the higher hydrophobicity of the material. A mathematical model is proposed to simulate the adsorption behaviour of butyl acetate over AgY(IE) and AgZSM-5(IE). The model parameters were successfully evaluated and used to accurately predict the breakthrough curves under various process conditions with root square mean errors of between 0.05 and 0.07.
    Matched MeSH terms: Silver/chemistry*
  20. The concentration and probabilistic risk assessment of potentially toxic elements in fillets of silver pomfret (Pampus argenteus): A global systematic review and meta-analysis
    Alipour M, Sarafraz M, Chavoshi H, Bay A, Nematollahi A, Sadani M, et al.
    J Environ Sci (China), 2021 Feb;100:167-180.
    PMID: 33279029 DOI: 10.1016/j.jes.2020.07.014
    The contamination of fish type products such as silver pomfret fish fillets by potentially toxic elements (PTEs) has raised global health concerns. Related studies regarding the concentration of PTEs in fillets of silver pomfret fish were retrieved among some international databases such as Scopus, PubMed and Embase between 1 January 1983 and 10 March 2020. The pooled (mean) concentration of PTEs in fillets of silver pomfret fish was meta-analyzed with the aid of a random-effect model (REM). Also, the non-carcinogenic risk was estimated via calculating the 95th percentile of the total target hazard quotient (TTHQ). The meta-analysis of 21 articles (containing 25 studies or data reports) indicated that the ranking of PTEs in fillets of silver pomfret fish was Fe (11,414.81 µg/kg wet weight, ww) > Zn (6055.72 µg/kg ww) > Cr (1825.79 µg/kg ww) > Pb (1486.44 µg/kg ww) > Se (1053.47 µg/kg ww) > Cd (992.50 µg/kg ww) > Ni (745.23 µg/kg ww) > Cu (669.71 µg/kg ww) > total As (408.24 µg/kg ww) > Co (87.03 µg/kg ww) > methyl Hg (46.58 µg/kg ww). The rank order of health risk assessment by country based on the TTHQ for adult consumers was Malaysia (2.500) > Bangladesh (0.886) > Iran (0.144) > China (0.045) > Pakistan (0.020) > India (0.015), while the corresponding values for child consumers was Malaysia (11.790) > Bangladesh (4.146) > Iran (0.675) > China (0.206) > Pakistan (0.096) > India (0.077). The adult consumers in Malaysia and children in Malaysia and Bangladesh were at considerable non-carcinogenic risk. Therefore, following the recommended control plans in order to reduce the health risk associated with the ingestion of PTEs via consumption of silver pomfret fish fillets is crucial.
    Matched MeSH terms: Silver*
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