Articles de revues : « Nanosilver formation »

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Cuong, Do Manh, Le Thanh Long, Hoang Thanh Tung, Vu Quoc Luan, Vu Thi Hien, Nguyen Thi Nhat Linh, Truong Thi Bich Phuong et Duong Tan Nhut. « The role of nanosilver in improving frequency of single cell formation of Limonium sinuatum (L.) Mill ». Vietnam Journal of Biotechnology 16, n^o 3 (18 décembre 2018) : 481–90. http://dx.doi.org/10.15625/1811-4989/16/3/11724.

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In this research, nanosilver with different concentrations and treatment time was used to sterilize infection agents and induce initial explants which were used as materials for cell suspension culture of Limonium sinuatum. The result showed that leaf explants sterilized with 0.2 g/L nanosilver for 20 minutes had highest effect (live rate 73.33%) comparing to HgCl2and Ca(ClO)2(56.66% and 64.44%, respectively). In addition, the leaf explants which were treated with nanosilver and cultured in ½ MS medium supplemented with 20 g/L sucrose, 1 mg/L picloram and 2.5 g/L gelrite also induced calli (friable calli, milk white color, embryogenic callus structure). Moreover, cell suspension formation process from these calli was also observed highest on the 20thday (49,088 cells/mL) in liquid shaking culture condition comparing to control treatment (19,361 cells/mL) when they were cultured on similar medium combined with 1.2 mg/Lnanosilver. These cells had the best growth, development and regeneration from the 16thday to the 20thday. The ability of shoot and callus regeneration was highest (67.77%) in ½ MS medium which was supplemented with 20 g/L sucrose, 1 mg/L zeatin, 2.5 g/L gelrite and 1.6 mg/L nanosilver compared with control treatment having no nanosilver (40.00%). This research showed that in micropropagation of Limonium sinuatum, nanosilver was proved to be an effective agent for sterilization, explant induction, cell suspension origination, and callus and shoot regeneration. Beside that, nanosilver had negative impact on the development of explants when it was used with high concentration for extended period.

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Lestari, Nanda Revita Dwi, et Sari Edi Cahyaningrum. « Synthesis and Characterization of Hydroxyapatite-Nanosilver as Anti Bacteria that Cause Dental Caries ». Indonesian Journal of Chemical Science 11, n^o 1 (1 mai 2022) : 33–40. http://dx.doi.org/10.15294/ijcs.v11i1.51070.

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The formation of dental caries is the result of the activity of Streptococcus mutans bacteria. Various attempts have been done to prevent dental caries. One of them is using oral preparations containing antibacterial compounds Hydroxyapatite-NanoSilver which is an active ingredient that can provide antimicrobial effects to prevent dental caries. This study aims to synthesize and characterize nanosilver hydroxyapatite as an antibacterial that causes dental caries. Physicochemical characterization and antibacterial test towards Streptococcus mutans bacteria with the active ingredient hydroxyapatite-nanosilver. In this study, hydroxyapatite-nanosilver materials with variations in nanosilver concentration of 4 ppm were used; 7 ppm; 10 ppm; 13 ppm; and 15 ppm. The results of FT-IR characterization showed the functional groups O-H, C=O, CO32-, and PO43-. The results of the PSA test showed that the hydroxyapatite-nanosilver formulation with a concentration of 10 ppm had the smallest nanoparticle size of 80.89 nm. Measurement of antibacterial activity test showed that the hydroxyapatite-nanosilver formulation was able to inhibit the growth of Streptococcus mutans bacteria. The highest diameter of resistance to the growth of mutant Streptococcus bacteria in hydroxyapatite-nanosilver formulations is 22.5 mm at a nanosilver concentration of 4 ppm.

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Liang, Xiao Jing, Gui Qing Wen et Zhi Liang Jiang. « Spectrophotometric Determination of Trace Hg²⁺ with hsDNA-Modified Nanosilver Probe ». Applied Mechanics and Materials 319 (mai 2013) : 513–16. http://dx.doi.org/10.4028/www.scientific.net/amm.319.513.

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Herring sperm DNA (hsDNA) was used to modify 5 nm nanosilver to obtain a hsDNA-nanosilver probe (Ag-hsDNA) for Hg2+. In the presence of Hg2+, it combined with hsDNA to produce Hg2+-hsDNA complexes and to release nanosilver particles, based on formation of stable T-Hg2+-T mismatches. Nanosilver particles aggregated to form larger nanosilver clusters and led the absorption at 412 nm decreased in the pH 6.5 Na2HPO4-NaH2PO4buffer solution and 0.05 mol/L NaCl medium. The decreased absorption (ΔA412nm) is linear to Hg2+concentration in the range of 1.36-10.86μg/L Hg2+, with regress equation of ΔA=0.0987CHg2++0.0624, correlation coefficient of 0.9890, and detection limit of 0.30μg/L Hg2+. The assay was applied to the analysis of Hg2+in wastewater with satisfactory results.

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Khachatryan, Karen, Lusine Khachatryan, Marcel Krzan, Magdalena Krystyjan, Lidia Krzemińska-Fiedorowicz, Anna Lenart-Boroń, Aneta Koronowicz, Mariola Drozdowska et Gohar Khachatryan. « Formation and Investigation of Physicochemical, Biological and Bacteriostatic Properties of Nanocomposite Foils Containing Silver Nanoparticles and Graphene Oxide in Hyaluronic Acid Matrix ». Materials 14, n^o 12 (18 juin 2021) : 3377. http://dx.doi.org/10.3390/ma14123377.

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Natural polysaccharides, including hyaluronic acid, find a wide range of applications in biomedical sciences. There is a growing interest in nanocomposites containing hyaluronic acid and nanoparticles such as nanometals or graphene. In this study, we prepared foils of pure sodium hyaluronate and sodium hyaluronate containing nanosilver, graphene oxide, nanosilver/graphene oxide and characterized their properties. UV-vis spectroscopy and scanning electron microscopy (SEM) confirmed the formation of 10–20 nm silver nanoparticles. The structural changes were investigated using Fourier transforms infrared (FTIR) spectra and size exclusion chromatography. The obtained results suggest changes in molecular weights in the samples containing nanoparticles, which was highest in a sample containing nanosilver/graphene oxide. We also assessed the mechanical properties of the foils (thickness, tensile strength and elongation at break) and their wettability. The foils containing nanosilver and nanosilver/graphene oxide presented bacteriostatic activity against E. coli, Staphylococcus spp. and Bacillus spp., which was not observed in the control and sample containing graphene oxide. The composites containing graphene oxide and nanosilver/graphene oxide exhibited a cytotoxic effect on human melanoma WM266-4 cell lines (ATCC, Manassas, VA, USA).

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Zaki, Sahar, Marwa Etarahony, Marwa Elkady et Desouky Abd-El-Haleem. « The Use of Bioflocculant and Bioflocculant-ProducingBacillus mojavensisStrain 32A to Synthesize Silver Nanoparticles ». Journal of Nanomaterials 2014 (2014) : 1–7. http://dx.doi.org/10.1155/2014/431089.

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It is preferable to use an organism to produce more than one product at the same time. So, the aim of this study was to investigate the ability of bioflocculant-producingBacillus mojavensisstrain 32A as a nanosilver synthesizer beside bioflocculant production. To achieve this target, three media, nutrient broth, bioflocculant-producing medium, and pure bioflocculant, were tested. Produced nanosilver was characterized by UV-vis, XRD, and TEM. In all cases, the results demonstrated that UV-vis showed a peak at ~420 nm corresponding to the plasmon absorbance of nanosilver. XRD spectrum exhibited 2θvalues corresponding to the silver nanocrystal that is produced in hexagonal and cubic crystal configurations. TEM confirmed formation, size, shape, and morphologies of nanosilver particles. The results emphasized that purified bioflocculant has the ability to produce anisotropy clusters of nanosilver ranging in size from 6 to 72 nm proving that the bioflocculant functioned as reducing and stabilizing agent in nanosilver synthesis.

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Swolana, Denis, Małgorzata Kępa, Celina Kruszniewska-Rajs et Robert D. Wojtyczka. « Antibiofilm Effect of Silver Nanoparticles in Changing the Biofilm-Related Gene Expression of Staphylococcus epidermidis ». International Journal of Molecular Sciences 23, n^o 16 (17 août 2022) : 9257. http://dx.doi.org/10.3390/ijms23169257.

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Nowadays, antibiotic resistance is a major public health problem. Among staphylococci, infections caused by Staphylococcus epidermidis (S. epidermidis) are frequent and difficult to eradicate. This is due to its ability to form biofilm. Among the antibiotic substances, nanosilver is of particular interest. Based on this information, we decided to investigate the effect of nanosilver on the viability, biofilm formation and gene expression of the icaADBC operon and the icaR gene for biofilm and non-biofilm S. epidermidis strains. As we observed, the viability of all the tested strains decreased with the use of nanosilver at a concentration of 5 µg/mL. The ability to form biofilm also decreased with the use of nanosilver at a concentration of 3 µg/mL. Genetic expression of the icaADBC operon and the icaR gene varied depending on the ability of the strain to form biofilm. Low concentrations of nanosilver may cause increased biofilm production, however no such effect was observed with high concentrations. This confirms that the use of nanoparticles at an appropriately high dose in any future therapy is of utmost importance. Data from our publication confirm the antibacterial and antibiotic properties of nanosilver. This effect was observed phenotypically and also by levels of gene expression.

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Putro, David Sarono, Dian E. Ermawati et Adi Yugatama. « Volume Variation of Sweet Orange (Citrus sinensis) Juice and Peel Extract Toward the Characteristic and Antibacterial Activity of Nanosilver ». Indonesian Journal of Pharmaceutical Science and Technology 9, n^o 1 (2 février 2022) : 31. http://dx.doi.org/10.24198/ijpst.v1i1.29870.

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Biosynthesis of nanosilver by using sweet orange (C. sinensis) as a bioreductor has shown nanosized results. In this research, the effect of volume variation of sweet orange juice and peel extract combination toward the characteristics and antibacterial activity of synthesized nanosilver will be studied. Solution of AgNO3 1 mM was mixed with a combination of sweet orange juice – peel extract with ratios (v/v), 3:0; 1.5:1.5; 1:2; 0.5:2.5 and 0:3 at 60˚C for 45 minutes. The color change of the mixed solution indicated the formation of nanosilver and confirmed by using UV/Vis spectrophotometer and TEM analysis. The results show that the addition of sweet orange juice in combination accelerated the color change of the mixed solution. The characterization of nanosilver with UV/Vis spectrophotometer confirmed SPR peak at 438-459 nm. The stability test showed that nanosilver reduced with sweet orange juice-peel extract 0,5:2,5 (v/v) was stable and had inhibition diameter tested by the diffusion method against S.aureus (19.50 mm) and S.epidermidis (18.09 mm), indicates a moderate inhibition. Its TEM analysis confirmed the particle's size of about 30-56 nm with spherical form.Keywords: nanosilver, biosynthesis, Citrus sinensis, characteristic, antibacterial activity

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Huma, Zil‐e, Ibrahim Javed, Zhenzhen Zhang, Hajira Bilal, Yunxiang Sun, Syed Zajif Hussain, Thomas P. Davis et al. « Nanosilver Mitigates Biofilm Formation via FapC Amyloidosis Inhibition ». Small 16, n^o 21 (27 janvier 2020) : 1906674. http://dx.doi.org/10.1002/smll.201906674.

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He, Maowei, Liling Sun, Kunyuan Hu, Yunlong Zhu, Lianbo Ma et Hanning Chen. « Drop-on-Demand Inkjet Printhead Performance Enhancement by Dynamic Lumped Element Modeling for Printable Electronics Fabrication ». Mathematical Problems in Engineering 2014 (2014) : 1–16. http://dx.doi.org/10.1155/2014/270679.

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The major challenge in printable electronics fabrication is the print resolution and accuracy. In this paper, the dynamic lumped element model (DLEM) is proposed to directly simulate an inkjet-printed nanosilver droplet formation process and used for predictively controlling jetting characteristics. The static lumped element model (LEM) previously developed by the authors is extended to dynamic model with time-varying equivalent circuits to characterize nonlinear behaviors of piezoelectric printhead. The model is then used to investigate how performance of the piezoelectric ceramic actuator influences jetting characteristics of nanosilver ink. Finally, the proposed DLEM is applied to predict the printing quality using nanosilver ink. Experimental results show that, compared to other analytic models, the proposed DLEM has a simpler structure with the sufficient simulation and prediction accuracy.

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Yang, Hui, et Jihui Wu. « Improvement of Sintering Performance of Nanosilver Paste by Tin Doping ». Journal of Nanomaterials 2020 (22 janvier 2020) : 1–6. http://dx.doi.org/10.1155/2020/3925276.

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Nanosilver paste, an interconnect solder, is a common choice in the electronics packaging industry. However, higher sintering temperature and lower sintering strength limit its application. At present, doped nanosilver paste has been studied for use in chip interconnection. In order to improve the sintering properties and shear strength of nanosilver paste, we have developed a new tin-doped nanosilver paste (referred to as silver tin paste), and according to the decomposition temperature of the organic dispersant in the slurry, a corresponding sintering process with a maximum temperature of 300°C was developed. The product after sintering of the silver tin paste is a mixture of a solid solution of Ag and an Ag3Sn phase. Among them, the hard and brittle phase Ag3Sn diffuse distribution in the silver matrix for strengthening, and the solid solution of Ag acts as a replacement solid solution strengthening. As the content of doped Sn increases, the sintering strength increases remarkably. When the Sn content is 5%, the joint shear strength reaches the highest value of 50 MPa. When it exceeds 5%, the sintering strength gradually decreases, which may be caused by the excessive formation of the intermetallic compound IMC as the dopant content increases. This new tin-doped nanosilver technology has the characteristics of low-temperature sintering and high-temperature service, so it is expected to be widely used in semiconductor power devices.

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Shi, Meng, Christopher C. H. Lin, Lan Wu, Christopher M. B. Holt, David Mitlin et Steven M. Kuznicki. « Nanosilver Particle Formation on a High Surface Area Titanate ». Journal of Nanoscience and Nanotechnology 10, n^o 12 (1 décembre 2010) : 8448–51. http://dx.doi.org/10.1166/jnn.2010.3715.

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Thuy, Nguyen Thi Thu, Nguyen Thi Thanh Bao et Do Hoang Tung. « Green Plasma Electrochemical Synthesized Colloidal Silver Nanoparticles and Their Antibacterial Activity ». Journal of Nanomaterials 2022 (20 septembre 2022) : 1–5. http://dx.doi.org/10.1155/2022/8677321.

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Nanosilver solutions of colloidal silver nanoparticles at reasonable price, good quality, and availability are increasingly demanded for the application in agriculture and aquaculture for the prevention and treatment of diseases. In this paper, we have applied a new simple and environmental-friendly fabrication method based on a plasma electrochemical procedure, where silver nanoparticles are directly formed in the plasma environment from silver ions generated by the electrochemical process from the silver anode. The electrode dissolution rate, the formation percentage, and quality of the silver nanoparticles were examined and evaluated using atomic absorption spectroscopy, electrode mass change, transmission electron microscopy, and UV-Vis absorption spectroscopy. The silver nanoparticle formation was found of nearly 100% with the rate of about 3.3 mg per minute. Spherical nanoparticles are found in quite homogenous size distribution around about 9.7 nm in the solution. The solution of the plasma synthesized nanosilvers shows better antibacterial property in comparison to that of AgNO3 of the same molar concentration on both normal and antibiotics resistant E. coli strains.

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Nowak, Nikola, Wiktoria Grzebieniarz, Gohar Khachatryan, Karen Khachatryan, Anna Konieczna-Molenda, Marcel Krzan et Jacek Grzyb. « Synthesis of Silver and Gold Nanoparticles in Sodium Alginate Matrix Enriched with Graphene Oxide and Investigation of Properties of the Obtained Thin Films ». Applied Sciences 11, n^o 9 (24 avril 2021) : 3857. http://dx.doi.org/10.3390/app11093857.

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Polymer nanocomposites containing nanometals became a subject of interest due to their bactericidal properties. Different polysaccharides have been used as matrices for nanosilver and nanogold synthesis. In this study, we present a novel, environmentally friendly method for the preparation of sodium alginate/nanosilver/graphene oxide (GOX) and sodium alginate/nanogold/graphene oxide GOX nanocomposites and their characteristics. The formation of approximately 10–20 nm ball-shaped Ag and Au nanoparticles was confirmed by UV–vis spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. The incorporation of GOX sheets within the ALG matrix improved the thermal stability of the nanocomposites film, which was measured using the differential scanning calorimetry (DSC). We also estimated the molecular weights of polysaccharide chains of the matrix with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). The composites were more prone to enzymatic hydrolysis. The strongest bacteriostatic activity was observed for the sample containing nanosilver.

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Aldubayyan, Abdulwahab Mohammed Rashed, Ahmed Tarik Ahmed Alsuawari, Bassam Mansour Alotaibi, Hussam Abdullah Fawaz Almalki, Faisal Saleh Alkhamis, Bader Al Hussein et Dr Shahzeb H. Ansari. « Effect of Nanosilver Fluoride Varnish on Demineralized Primary Teeth : A Systematic Review ». Saudi Journal of Oral and Dental Research 7, n^o 1 (18 janvier 2022) : 18–24. http://dx.doi.org/10.36348/sjodr.2022.v07i01.004.

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Demineralization of teeth or caries is a common health problem among pediatric patients. It is a more serious issue among children from low-income households due to their lack of access to proper dental care. Silver diamine fluoride (SDF) is an effective agent used to treat demineralization, but experiments are being done to replace it with nanosilver fluoride (NSF). The purpose of this study was to assess the effectiveness of nanosilver fluoride varnish in containing demineralization of primary teeth. A systematic literature review method was used. About 15 articles met the inclusion criteria. Findings are conflicting, but most of the reviewed studies confirmed the effectiveness of an agent with nanoparticles compared to all other alternatives, especially SDF. Apart from suppressing microorganisms that cause demineralization at very low concentrations, agents with nanoparticles protect patients from discoloration of teeth and formation stains. Nanosilver fluoride varnish can be used to replace the current alternatives, but the findings should be used with caution since most of the present studies are experimental.

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Kędzierska, Magdalena, Piotr Potemski, Anna Drabczyk, Sonia Kudłacik-Kramarczyk, Magdalena Głąb, Beata Grabowska, Dariusz Mierzwiński et Bożena Tyliszczak. « The Synthesis Methodology of PEGylated Fe3O4@Ag Nanoparticles Supported by Their Physicochemical Evaluation ». Molecules 26, n^o 6 (20 mars 2021) : 1744. http://dx.doi.org/10.3390/molecules26061744.

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Many investigations are currently being performed to develop the effective synthesis methodology of magnetic nanoparticles with appropriately functionalized surfaces. Here, the novelty of the presented work involves the preparation of nano-sized PEGylated Fe3O4@Ag particles, i.e., the main purpose was the synthesis of magnetic nanoparticles with a functionalized surface. Firstly, Fe3O4 particles were prepared via the Massart process. Next, Ag+ reduction was conducted in the presence of Fe3O4 particles to form a nanosilver coating. The reaction was performed with arabic gum as a stabilizing agent. Sound energy-using sonication was applied to disintegrate the particles’ agglomerates. Next, the PEGylation process aimed at the formation of a coating on the particles’ surface using PEG (poly(ethylene glycol)) has been performed. It was proved that the arabic gum limited the agglomeration of nanoparticles, which was probably caused by the steric effect caused by the branched compounds from the stabilizer that adsorbed on the surface of nanoparticles. This effect was also enhanced by the electrostatic repulsions. The process of sonication caused the disintegration of aggregates. Formation of iron (II, III) oxide with a cubic structure was proved by diffraction peaks. Formation of a nanosilver coating on the Fe3O4 nanoparticles was confirmed by diffraction peaks with 2θ values 38.15° and 44.35°. PEG coating on the particles’ surface was proven via FT-IR (Fourier Transform Infrared Spectroscopy) analysis. Obtained PEG–nanosilver-coated Fe3O4 nanoparticles may find applications as carriers for targeted drug delivery using an external magnetic field.

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Nugroho, Browi, et Sari Edi Cahyaningrum. « Synthesis and characterization of hydroxyapatite-nanosilver-clove oil (Eugenia Caryophyllus) as antibacterial in toothpaste preparations against streptococcus mutans bacteria ». Jurnal Pijar Mipa 18, n^o 4 (31 juillet 2023) : 659–65. http://dx.doi.org/10.29303/jpm.v18i4.5325.

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The formation of dental caries results from the activity of Streptococcus mutans bacteria. One of the efforts to prevent dental caries is using toothpaste containing antibacterial compounds such as hydroxyapatite-nanosilver-clove oil. This study aims to synthesize and characterize hydroxyapatite-nanosilver-cloves oil as an antibacterial that causes dental caries. In this study, physical properties were tested, namely, particle size with PSA, spreadability, stickiness, homogeneity, and chemical properties tested in functional groups with FTIR, pH, and antibacterial activity with the disc diffusion method. This study used 2% hydroxyapatite, ten ppm nanosilver, tween 80, xanthan gum, 70% sorbitol, sodium benzoate, sodium lauryl sulfate, sodium saccharin, calcium carbonate, peppermint, distilled water, clove oil with variations in the addition of concentrations of 1%, 2%, 3%, and 4%. The synthesis results produced a toothpaste preparation made from hydroxyapatite-nanosilver-clove oil, as evidenced by the results of FTIR characterization showing the presence of OH-, CO32-, PO43-, C-H, C-O, and C=O functional groups. PSA results show hydroxyapatite-nanosilver-clove oil has an average size of 4464 nm which is not included in the nanoparticle category (<100 nm). The toothpaste spreadability test resulted in a spread diameter of 5-6 cm, which met the requirements for paste spreadability (5-7 cm), while the adhesion test resulted in adhesion (7-12 seconds) which has not met the ideal requirements (1-6 seconds). The pH measurement resulted in a toothpaste pH of 8.8-9.0 per SNI (4.5-10.5). The homogeneity test of the toothpaste has met the requirements according to SNI, namely the absence of air bubbles, clumps, and separated particles. The antibacterial activity test showed that the hydroxyapatite-nanosilver-clove oil toothpaste formulation was able to inhibit the growth of S.mutans bacteria with the highest inhibition diameter in the variation of adding 4% concentration of clove oil, namely 14.99 mm with normally distributed data (p>0.05). One Way ANOVA statistical analysis showed that the treatment variation had a significantly different effect (p<0.05). These results indicate that adding clove oil into the formulation of hydroxyapatite-nanosilver-clove oil toothpaste can affect its chemical, physical, and antibacterial activity.

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Tang, Ying, Zeguo Jia, Xueting Li, Xiaotong Zhao, Shiqi Zhang, Li Luo, Li Xia, Zhaohui Fang, Yuanzhi Zhang et Mingwei Chen. « Mechanism of wound repair in diabetic rats using nanosilver-free alginate dressing ». Journal of Wound Care 32, Sup8 (2 août 2023) : cli—clx. http://dx.doi.org/10.12968/jowc.2023.32.sup8.cli.

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Objective: Nanosilver-alginate dressing can effectively promote the healing of diabetic wounds in rats. However, due to the potential toxicity of nanosilver, its widespread application in hard-to-heal wound healing is limited. In the present study, the role and potential mechanism of nanosilver-free alginate gel (NSFAG) in the healing process of diabetic wounds were explored. Method: A diabetic rat skin wound model was established, and wounds were treated with saline (NC group), nanosilver gel (NSG group) or nanosilver-free alginate gel (NSFAG group) for seven consecutive days. Results: NSFAG significantly promoted wound healing and increased the content of protein and hydroxyproline in granulation tissues, and was superior to NSG (p<0.05). Immunohistochemical analyses revealed that the skin wound tissue structure of the NSFAG group was intact, and the number of skin appendages in the dermis layer was significantly higher compared with the NC group and the NSG group (p<0.05). Western blot analysis found that the protein expression of the epidermal stem cell marker molecules CK19 and CK14 as well the proliferation marker of keratinocytes Ki67 in the NSFAG group was significantly higher compared with the NC group or NSG group (p<0.05). Additionally, the proliferation marker of keratinocytes Ki67 in the NSFAG group was significantly higher compared with the NC or NSG group (p<0.05). Immunofluorescence staining analyses indicated that the CK19- and CK14-positive cells were mainly distributed around the epidermis and the newly formed appendages in the NSFAG group, and this result was not observed in the NC or NSG groups. Conclusion: The present findings demonstrate that NSFAG can effectively accelerate wound healing in diabetic rats by promoting epidermal stem cell proliferation and differentiation into skin cells, as well as formation of granulation tissue, suggesting that it can be a potential dressing for diabetic wounds.

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Staniczek, Jakub, Żaneta Jastrzębska-Stojko et Rafał Stojko. « Biological Activity of Propolis Ointment with the Addition of 1% Nanosilver in the Treatment of Experimentally-Evoked Burn Wounds ». Polymers 13, n^o 14 (14 juillet 2021) : 2312. http://dx.doi.org/10.3390/polym13142312.

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The main objective of this study was to assess the pharmacological efficacy of ointments containing 1% propolis and 1% nanosilver, compared to the conventional treatment of burn wounds. In the evaluation of the results, we used clinical observation of scars, microbiological examinations, pathomorphological examinations, and analysis of free radicals. The analysis of the experiment results concerning the therapeutic effectiveness of the propolis ointment revealed its wide-ranging antibacterial action (against Gram-positive and Gram-negative bacteria). The 1% propolis ointment was found to accelerate neoangiogenesis and epithelialization, have a positive effect on the healing of burn wounds, improve the cosmetic look of scars, and have no side-effects. The analysis of free radicals in burn wounds showed impressive activity of the 1% nanosilver ointment in the reduction of free radicals. No synergism of pharmacological activity of propolis and nanosilver was shown. A comparative evaluation of the acquired research material allows us to provide a favorable opinion on the topical treatment of burn wounds with 1% propolis. The obtained results show that the 1% propolis ointment reduces healing time, offers antimicrobial action, and has a positive effect on the normal process of scar formation.

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Latko-Durałek, Paulina, Józef Rzempołuch, Monika Staniszewska, Karina Rosłoniec, Monika Bil, Rafał Kozera et Anna Boczkowska. « The Antifungal Fibers of Polyamide 12 Containing Silver and Metal Oxides ». Materials 16, n^o 17 (25 août 2023) : 5837. http://dx.doi.org/10.3390/ma16175837.

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The textile market is a vast industry that utilizes antimicrobial polymeric materials, including various types of fabrics, for medical and personal protection applications. Therefore, this study focused on examining four types of antimicrobial fillers, namely, metal oxides (zinc, titanium, copper) and nanosilver, as fillers in Polyamide 12 fibers. These fillers can be applied in the knitting or weaving processes to obtain woven polymeric fabrics for medical applications. The production of the fibers in this study involved a two-step approach: twin-screw extrusion and melt spinning. The resulting fibers were then characterized for their thermal properties (TGA, DSC), mechanical performance (tensile test, DMA), and antifungal activity. The findings of the study indicated that all of the fibers modified with fillers kill Candida albicans. However, the fibers containing a combination of metal oxides and silver showed significantly higher antifungal activity (reduction rate % R = 86) compared to the fibers with only a mixture of metal oxides (% R = 21). Furthermore, the inclusion of metal oxides and nanosilver in the Polyamide 12 matrix hindered the formation of the crystal phase and decreased slightly the thermal stability and mechanical properties, especially for the composites with nanosilver. It was attributed to their worse dispersion and the presence of agglomerates.

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Fischer, Melissa, Florian Gebhard, Timo Hammer, Christian Zurek, Guido Meurer, Christoph Marquardt et Dirk Hoefer. « Microbial alginate dressings show improved binding capacity for pathophysiological factors in chronic wounds compared to commercial alginate dressings of marine origin ». Journal of Biomaterials Applications 31, n^o 9 (29 mars 2017) : 1267–76. http://dx.doi.org/10.1177/0885328217702173.

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Marine alginates are well established in wound management. Compared with different modern wound dressings, marine alginates cannot prove superior effects on wound healing. Alginates from bacteria have never been studied for medical applications so far, although the microbial polymer raises expectations for improved binding of wound factors because of its unique O-acetylation. Due to its possible positive effects on wound healing, alginates from bacteria might be a superior future medical product for clinical use. To prove the binding capacity of microbial alginates to pathophysiological factors in chronic wounds, we processed microbial alginate fibres, produced from fermentation of the soil bacterium Azotobacter vinelandii ATCC 9046, into needle web dressings and compared them with commercial dressings made of marine alginate. Four dressings were assessed: Marine alginate dressings containing either ionic silver or zinc/manganese/calcium, and microbial alginate dressings with and without nanosilver. All dressings were tested in an in vitro approach for influence on chronic wound parameters such as elastase, matrix metalloproteases-2, tumour necrosis factor-α, interleukin-8, and free radical formation. Despite the alginate origin or addition of antimicrobials, all dressings were able to reduce the concentration of the proinflammatory cytokines TNF-α and IL-8. However, microbial alginate was found to bind considerable larger amounts of elastase and matrix metalloproteases-2 in contrast to the marine alginate dressings. The incorporation of zinc, silver or nanosilver into alginate fibres did not improve their binding capacity for proteases or cytokines. The addition of nanosilver slightly enhanced the antioxidant capacity of microbial alginate dressings, whereas the marine alginate dressing containing zinc/manganese/calcium was unable to inhibit the formation of free radicals. The enhanced binding affinity by microbial alginate of Azotobacter vinelandii to pathophysiological factors may be interesting to support optimal conditions for wound healing.

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Amutha, M., P. Lalitha et M. Jannathul Firdhouse. « Biosynthesis of Silver Nanoparticles UsingKedrostis foetidissima (Jacq.) Cogn. » Journal of Nanotechnology 2014 (2014) : 1–5. http://dx.doi.org/10.1155/2014/860875.

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Nanosilver was synthesized using the aqueous solution of solvent extracts of leaf and stem ofKedrostis foetidissima. Three different methods of formation of silver nanoparticles such as reaction at (i) room temperature, (ii) higher temperature, and (iii) sonication were employed in the present study. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, X-ray diffractometer, Scherrer’s formula, scanning electron microscopy, and FTIR analysis.

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Wang, Chaoqun, Xiao Liu, Zhen Han, Xu Zhang, Jingjing Wang, Kai Wang, Zhengtao Yang et Zhengkai Wei. « Nanosilver induces the formation of neutrophil extracellular traps in mouse neutrophil granulocytes ». Ecotoxicology and Environmental Safety 183 (novembre 2019) : 109508. http://dx.doi.org/10.1016/j.ecoenv.2019.109508.

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Nugroho, Bambang Hernawan, Rika Artikawati et Suparmi Suparmi. « Development innovation of silver nanoparticles used leaves of banana (Musa sapientum) as eco-friendly bioreductor ». Jurnal Ilmiah Farmasi 17, n^o 1 (31 juillet 2021) : 64–73. http://dx.doi.org/10.20885/jif.vol17.iss1.art7.

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Background: Silver nanoparticle could be developed by natural reducing agent like Epigallocatechin Gallate (EGCG) of banana leaves (Musa sapientum) as bioreductor in biosynthesis. Objective: This study aimed to examine the formulation and characterization of silver nanoparticles using the combination of banana leaf (M. sapientum) extract containing epigallocatechin gallate (EGCG) for biosynthesis. The biosynthesis of silver nanoparticles is eco-friendly and low energy process. Method: Each formula was added with 500microlitre AgNO3. Identification of nanoparticles was characterized by duration of its discoloration, its absorbance using UV/Vis spectrophotometer and FTIR, its particle size using PSA, and its morphology under TEM. Result: The silver nanoparticle formation need less than 15 minutes. The measurement of its absorbance showed the wavelength of this silver nanoparticles are in the range of 410-480nm. Characterization using FTIR showed a decrease in absorption of the functional -OH group spectrum. This particle has the smallest particle size in value of 57.16 ± 0.40 nm in spherical shape. Conclusion: Nanosilver could be prepared using banana leaf extract using low energy biosynthesis process. Keywords: characterization, nanosilver, banana leaf (M. sapientum)

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Ahmad, Muhammad Sannan, Hira Musaddiq et Mirza Imran Shahzad. « Anti MRSA and Antiviral Evaluation of Nano Silver Against Avian Influenza virus ». FRONTIERS IN CHEMICAL SCIENCES 1, n^o 2 (31 décembre 2020) : 59–66. http://dx.doi.org/10.52700/fcs.v1i2.11.

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Preparation of nano sized silver particles was performed by using flower extract of Aerva javanica (AJ). Conversion of Ag+ ions to nanoscaled Ago was carried out in 90 min reaction by green approach. Antiviral potential of nanosilver (NS) was evaluated against Avian Influenza Virus (AIV) strain H9N2, in 9-11 days old chicken embryonated eggs. Synthesized particles were also screened against four methicillin-resistant Staphylococcus aureus (MRSA) strains by well diffusion method. Formation of spherical particles was confirmed by SPR band at 428 nm. XRD analysis confirmed face centred cubic crystal structure of particles with average particle size of 15 nm as calculated by Debye–Scherrer’s formula. Remarkable anti AIV activity was observed from NS particles with IC50 value 50 ?g/ml and this value is 200 times greater control drug i.e., Amantadine. Synthesized particles were also screened against four methicillin-resistant Staphylococcus aureus (MRSA) strains by well diffusion method. Significantly high antiviral and antibacterial activities were observed from nanosilver particles against AIV H9N2 and all four MRSA strains.Keywords:

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Goud, S. V. Ramesh, K. Raja Sigamani, Bhaskar, Kurinchi Kumaran, Mohammed Arafat et S. N. Reddy Duvvuri. « Comparitive evaluation of antimicrobial effectiveness of silver oxide coatings on different types of ceramic brackets against Streptococcus mutans ». Journal of Dental Panacea 4, n^o 2 (15 juin 2022) : 75–79. http://dx.doi.org/10.18231/j.jdp.2022.015.

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The historical aspect of nanotechnology dates back to 600 BC. Taniguchi was the first to use the term nanotechnology in 1974, originating from a Greek word meaning “dwarf”. Nanotechnology when combined with dentistry and medicine created an interdisciplinary field i.e., nanodentistry and nanomedicine and this combination gets engineers, chemists, physicians on a single platform having various applications in detection, imaging and drug delivery devices.With respect to orthodontics, the nanoparticle coated archwires, adhesives, temporary anchorage devices, brackets, orthodontic wires with shape memory and biofilm control features have been applied. Silver nanoparticles are combined with different accessory orthodontic materials which results in the addition of more antimicrobial properties which inturn decreases the biofilm formation and maintain better oral health. Antibacterial effectiveness of nanosilver coated materials has been shown with and without the release of nanosilver ions in in vitro studies. In addition, long-term inhibitory effects against S.mutans have been found while no nanosilver ions were released. 30 MBT 0.022’’ monocrystalline ceramic brackets and 30 MBT 0.022’’ polycrystalline ceramic brackets (Metro Orthodontics) which are randomly divided into 4 groups: 2 control groups (group-1=15 uncoated monocrystalline and group-2=15 uncoated polycrystalline) and 2 experimental groups (group-3=15 silver oxide coated monocrystalline and group-4=15 silver oxide coated polycrystalline). S.mutans counts were significantly less in the experimental groups than control groups. Silver oxide coatings on ceramic brackets reduced the colony forming units of S. mutans. Both monocrystalline and polycrystalline coated brackets showed reduced number of colony forming units than their control groups.

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ZHELTONOZHSKAYA, T. B., L. V. SHEVCHENKO, N. M. PERMYAKOVA, Y. Y. DOVBNIA, V. V. KLEPKO et D. O. KLYMCHUK. « PROMISING NANOBIOTECHNOLOGY FOR POULTRY FARMING BASED ON SILVER NANOPARTICLES EMBEDDED IN POLYMER-INORGANIC HYBRID CARRIERS ». Polymer journal 45, n^o 2 (15 mai 2023) : 153–74. http://dx.doi.org/10.15407/polymerj.45.02.153.

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A promising composite material is proposed to reduce the endogenous and exogenous contamination of chicken eggs with pathogenic microflora during their formation and storage. It is based on hybrid biocompatible and biodegradable silica/polyacrylamide nanocarriers containing small silver nanoparticles (dav=2.4±1.0 nm) that are orally administered to laying hens with drinking water. The features of the formation of nanosilver in hybrid carriers by borohydride reduction of a silver salt at its various concentrations in an aqueous solution have been studied. An interesting effect of the sharp appearance of the second surface plasmon resonance band in the UV-Vis spectra of a silver salt/hybrid mixture at a high salt concentration was found. This was explained by sharp structural changes in the hybrid carriers caused by the simultaneous growth of many AgNPs in them. It was assumed that the intensive growth of many AgNPs in one hybrid particle was accompanied by detachment of the grafted PAAm chains from the SiO2 surface due to the breaking of hydrogen bonds. The change in the state of the composite material under the influence of the pH of the solution, the concentration of nanoparticles, the presence of NaCl (as in a “physiological solution”), and visible light was studied by UV-Vis spectroscopy, potentiometric titration, and TEM. Nanosilver in carriers showed high stability with respect to most of these factors. The influence of the composite material on the clinical state of laying hens and important parameters of their eggs and blood was studied when it was administered orally with drinking water three times every 10 days at doses of 0.2 and 0.4 mg per chicken per day. A striking effect of selective endogenous accumulation of silver in eggshells has been revealed. This confirmed the penetration of the nanosilver composite into the circulatory system of chickens by passing through the digestive tract, absorption through the intestinal epithelium and further transport into the tissues of the chickens, including the oviducts, where protein and eggshell are formed. Such penetration did not cause a toxic effect on the body of laying hens.

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Kwon, Jae-Sung, Dong Lee et Je Oh. « Formation and Characterization of Inkjet-Printed Nanosilver Lines on Plasma-Treated Glass Substrates ». Applied Sciences 8, n^o 2 (12 février 2018) : 280. http://dx.doi.org/10.3390/app8020280.

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Chourabi, Kalthoum, Lobna Elleuch, Salma Kloula, Ahmed Landoulsi et Abdelwaheb Chatti. « Antimicrobial and Antibiofilm Effects of Silver Nanoparticles Produced by Yarrowia lipolytica Against Vegetative and Starved Shigella ». Nano 16, n^o 08 (juillet 2021) : 2150088. http://dx.doi.org/10.1142/s1793292021500880.

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Silver nanoparticles have attracted much interest from scientists to develop nanosilver-based disinfectant products due to their unique properties of high antimicrobial activity. This study focused on biosynthesis, characterization, antimicrobial and antibiofilm effects of silver nanoparticles against vegetative and starved Shigella strains. The silver nanoparticles were synthesized using the yeast Yarrowia lipolytica and characterized by ultraviolet–visible spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The antimicrobial and antibiofilm activities of silver nanoparticles were tested against the growth of vegetative and starved Shigella strains. After the addition of silver nitrate solution to the supernatant of Y. lipolytica, we noticed the appearance of a brown-black coloration that suggested the formation of silver nanoparticles. The presence of silver nanoparticles was manifested by a maximum absorption in the ultraviolet–visible range, precisely at the wavelength 420[Formula: see text]nm. The crystalline nature and the stability of silver nanoparticles were confirmed, respectively, by XRD and FTIR analysis. The antibacterial activity of silver nanoparticles showed significant toxicity on Shigella strains indicating that the starved cells were more sensitive to treatment with silver nanoparticles than vegetative cells. Surprisingly, the biofilm formation had not been inhibited by silver nanoparticles for both vegetative and starved cells. In conclusion, a new class of nanosilver containing disinfectant nanoproducts will be promising for advanced environmental treatments including air disinfection, water disinfection, surface disinfection and personal hygiene that will help to prevent the further outbreak of diseases.

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Kannaiyan, Suba, D. Easwaramoorthi, Karthik Kannan, Andal Gopal, R. Lakshmipathy, Khadijah Mohammedsaleh Katubi, Nayef S. Almuaikel et Ivan Leandro Rodriguez Rico. « Pisonia Alba Assisted Synthesis of Nanosilver for Wound Healing Activity ». Bioinorganic Chemistry and Applications 2022 (12 septembre 2022) : 1–8. http://dx.doi.org/10.1155/2022/1775198.

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Wound infection is a major clinical challenge, impacting patient morbidity and mortality, with significant economic implications. Our research focused on how Pisonia Alba (PA) leaves, which are used to treat wounds, are used to synthesize silver nanoparticles and study their wound healing property. UV-visible spectroscopy, X-ray diffraction analysis, and s electron microscope (SEM) analysis were employed to evaluate the synthesized silver nanoparticles. Using DLS and Zeta potential analysis, the size and stability of the Pisonia Alba capped silver nanoparticle were investigated. The results showed that Pisonia Alba extract stabilized silver nanoparticles are 63.88 nm in size and have a spherical shape. Antibacterial and antibiofilm potential of synthesized silver nanoparticles against pathogenic organisms Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria were investigated. The in vitro cell scratch wounding assay is used to investigate the wound healing properties of synthesized nanoparticles. Pisonia Alba stabilized silver nanoparticles (PA@AgNPs), in comparison to Pisonia Alba (PA) extract, show effective wound healing characteristics by inducing the formation of collagen and serving as a capable wound healing agent.

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N., Ahmad, B. C. Ang, Amalina M.A. et C. W. Bong. « Influence of Precursor Concentration and Temperature on the Formation of Nanosilver in Chemical Reduction Method ». Sains Malaysiana 47, n^o 1 (31 janvier 2018) : 157–68. http://dx.doi.org/10.17576/jsm-2018-4701-19.

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Morozova, Olga V. « Silver Nanostructures : Limited Sensitivity of Detection, Toxicity and Anti-Inflammation Effects ». International Journal of Molecular Sciences 22, n^o 18 (14 septembre 2021) : 9928. http://dx.doi.org/10.3390/ijms22189928.

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Nanosilver with sizes 1–100 nm at least in one dimension is widely used due to physicochemical, anti-inflammatory, anti-angiogenesis, antiplatelet, antifungal, anticancer, antibacterial, and antiviral properties. Three modes of the nanosilver action were suggested: “Trojan horse”, inductive, and quantum mechanical. The Ag+ cations have an affinity to thiol, amino, phosphate, and carboxyl groups. Multiple mechanisms of action towards proteins, DNA, and membranes reduce a risk of pathogen resistance but inevitably cause toxicity for cells and organisms. Silver nanoparticles (AgNP) are known to generate two reactive oxygen species (ROS)-superoxide (•O2−) and hydroxyl (•OH) radicals, which inhibit the cellular antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and cause mechanical damage of membranes. Ag+ release and replacement by electrolyte ions with potential formation of insoluble AgCl result in NP instability and interactions of heavy metals with nucleic acids and proteins. Protein shells protect AgNP core from oxidation, dissolution, and aggregation, and provide specific interactions with ligands. These nanoconjugates can be used for immunoassays and diagnostics, but the sensitivity is limited at 10 pg and specificity is restricted by binding with protective proteins (immunoglobulins, fibrinogen, albumin, and others). Thus, broad implementation of Ag nanostructures revealed limitations such as instability; binding with major blood proteins; damage of proteins, nucleic acids, and membranes; and immunosuppression of the majority of cytokines.

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Ma, Lian Bo, Mao Wei He, Kun Yuan Hu et Yun Long Zhu. « Modeling and Optimizing Industrial Inkjet Printhead for Printable Electronics Fabrication ». Applied Mechanics and Materials 748 (avril 2015) : 15–19. http://dx.doi.org/10.4028/www.scientific.net/amm.748.15.

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The most significant issues in printable electronics fabrication are the printing quality and efficiency delivered by drop-on-demand (DOD) industrial inkjet printhead. Aiming to characterize the nonlinear behaviors of piezoelectric inkjet printhead, the dynamic lumped element model (DLEM) is proposed to cast the original LEM into a time-varying and nonlinear fashion. At the same time , the PSO-based optimization for paramenters is incorporated in DLEM. Due to new characteristics, DLEM can accurately simulate the inkjet-printed nanosilver droplet formation process and effectively predicate optimal combinations of high-frequency driving waveform with high printing quality. From extensive experimental studies, the effectiveness and efficiency of the proposed DLEM is validated.

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Daghestani, Maha, Sarah A. Al Rashed, Wadha Bukhari, Badryah Al-Ojayan, Eiman M. Ibrahim, Asma M. Al-Qahtani, Nada M. Merghani, Rasha Ramadan et Ramesa Shafi Bhat. « Bactericidal and cytotoxic properties of green synthesized nanosilver using Rosmarinus officinalis leaves ». Green Processing and Synthesis 9, n^o 1 (3 mai 2020) : 230–36. http://dx.doi.org/10.1515/gps-2020-0025.

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AbstractGreen synthesized nanoparticles from plant extracts are being used in various biomedical applications, particularly because of their bactericidal and cytotoxic activities. In this study, silver nanoparticles (AgNPs) were successfully synthesized from the Rosmarinus officinalis aqueous leaf extract. Different spectroscopic and microscopic analyses such as ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and energy-dispersive X-ray spectroscopy were performed to verify the biosynthesized AgNPs in our sample. The formation of nanosilver particles was preliminarily confirmed by UV-vis spectroscopy at 400 nm. The presence of carboxylic or amide groups was confirmed by FTIR, for the reduction of the silver ion. Transmission electron microscopy confirmed a particle size of 12–22 nm. The prepared AgNPs showed good antibacterial activity against human pathogens and good cytotoxic activity against the human breast cancer cell line (MDA MB 231). The nanoparticles prepared from R. officinalis can be used for various biomedical applications.

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Taghiyari, Hamid R., Siavash Bayani, Holger Militz et Antonios N. Papadopoulos. « Heat Treatment of Pine Wood : Possible Effect of Impregnation with Silver Nanosuspension ». Forests 11, n^o 4 (20 avril 2020) : 466. http://dx.doi.org/10.3390/f11040466.

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The scope of the present work was to study the effects of heat treatment (at different mild temperatures) on the physicomechanical properties of pine wood, and to find out if impregnation with nanosilver may have any potential influence on the impact of heat treatment. Impregnation of wood with a 400-ppm silver nanosuspension was carried out under an initial vacuum pressure of 0.07 MPa, followed by a pressure of 0.25 MPa for thirty minutes, before heat treatment. Heat treatment was carried out under hot air at three relatively mild temperatures, 145, 165, and 185 °C. Results showed improvement of some properties in heat-treated wood at 145 °C. This was indicative of the improving impact caused by hornification and irreversible hydrogen bonding in the course of water movements due to heat treatment; significant fluctuations in the intensities of FTIR spectra bands at 1750–1500 cm−1 were corroborating evidence of chemical alterations in hemicellulose polymer. The high mass loss at temperature 185 °C, and the extreme thermal degradation thereof, overcame the improving effects of hornification and formation of irreversible hydrogen bonds, consequently mechanical properties decreased significantly. Interaction of different elements involved made it hard to predict properties in specimens modified at 165 °C. Impregnation of specimens with nanosilver suspension resulted in significant increase of mass loss in specimens heat-treated at 185 °C, and significant fluctuations in properties of specimens heat-treated at 145 °C.

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Calata, Jesus N., Hanguang Zheng, Guo-Quan Lu, Khai Ngo et Luu Nguyen. « Small-chip Attachment on Copper Leadframe with Sintered Nanosilver Paste ». International Symposium on Microelectronics 2013, n^o 1 (1 janvier 2013) : 000072–77. http://dx.doi.org/10.4071/isom-2013-ta32.

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Sintered nanoscale silver paste provides a low-temperature alternative to solder for die attachment. Unlike solder, the sintered attachment does not melt upon reaching the original attachment temperature and therefore may be used at higher temperatures. Higher electrical and thermal conductivities mean less Joule heating and better heat dissipation characteristics and the porous microstructure imparts low elastic modulus for lower thermomechanical stress and enhanced reliability. The state of the technology has reached a point where it is now possible to obtain die-shear strengths comparable to solder at sintering temperatures between 250°C and 280°C with little or no applied pressure, depending on the chip size. In addition to attachments on silver or gold-coated surfaces, it is possible to form bonds on bare copper if done under inert or slightly reducing atmosphere. Because attainment of a strong bond depends on the paste being in contact with a clean (oxide-free or untarnished) surface, a study was made to determine if the attachment process will work on copper leadframes with either an anti-tarnish or anti-EBO (epoxy bleed-out) coating. Small mechanical silicon chips less that 3 mm × 3 mm in size were attached without pressure at temperatures as low as 260°C. The sintering atmosphere in the chamber was varied from pure nitrogen, to nitrogen + 4% hydrogen and to nitrogen + 1% oxygen. Attachments sintered in pure nitrogen or nitrogen with hydrogen produced die-shear strengths of at least 30 MPa and were just as strong as those bonded on bare copper. Sintering in nitrogen + 1 % oxygen caused the die-shear strength to drop below 30 MPa but still above 20 MPa. In the presence of oxygen, the binder removal is due to oxidative combustion but the low level of oxygen caused incomplete binder burnout that interfered with the sintering while also causing some oxidation of the copper. On the other hand, the addition of hydrogen appeared to enhance the sintered microstructure accompanied by a slight increase in die shear strength. Sheared attachments that exposed the copper surface showed patches of silver still attached indicating formation of strong bond with the copper.

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Lin, Hong, Ling Chen, De Suo Zhang et Yu Yue Chen. « Silver Nanoparticles by Amino-Terminated Hyperbranched Polymer : Characterization and Antimicrobial Property on Cotton ». Advanced Materials Research 332-334 (septembre 2011) : 930–34. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.930.

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A hyperbranched polymer (HBP-NH2) acting as a reducing agent and stablizer agent has been synthesized to investigate the stability of silver nanoparticles antimicrobial agent, which were prepared in a hyperbranched polymer matrix by a reaction with silver nitrate solution. The antimicrobial agents generated were characterized by different spectroscopic and analytical techniques such as DLS, TEM and UV-vis, which conﬁrm the formation of well-dispersed silver nanoparticles with average size around 12.0 nm. Furthermore, antimicrobial and mechanical properties of nanosilver treated cotton fabrics were investigated. The results showed that stable silver nanoparticles collide solution with 12 nm, applied on cotton fabric under certain condition, could produce ideal antibacterial rate over 94% against both Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) even after 50 consecutive washings.

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Li, Lingxiangyu, Qunfang Zhou, Fanglan Geng, Yawei Wang et Guibin Jiang. « Formation of Nanosilver from Silver Sulfide Nanoparticles in Natural Waters by Photoinduced Fe(II, III) Redox Cycling ». Environmental Science & ; Technology 50, n^o 24 (28 novembre 2016) : 13342–50. http://dx.doi.org/10.1021/acs.est.6b04042.

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Yang, Ming Shan, Xin Pin Wen et Lin Kai Li. « The Green Preparation of Nano-Silver Particle by Reductive Polysaccharide ». Advanced Materials Research 983 (juin 2014) : 79–83. http://dx.doi.org/10.4028/www.scientific.net/amr.983.79.

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Silver nanoparticles have been prepared using reductive polysaccharides (glucan) as protecting agents and silver nitrate as precursor via a facile green approach, and possible formation mechanism of silver nanoparticle was proposed in this paper. Silver nanoparticles appearance, size and size distribution were controlled by different synthesis technologies and reaction conditions. By changing the reaction conditions such as AgNO3 solution concentration, glucan dosage, reaction temperature, reaction time, the parameters affecting the product shape, particle size and size distribution were investigated. The samples synthesized were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectrophotometer (UV-vis) methods. The results have showed that nanosilver particle with different shapes such as rod-like, sheet-like or flake and tree-like etc. can be prepared by reductive polysaccharides, and it is a green preparation technology.

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Dybowska-Sarapuk, Łucja, Andrzej Kotela, Jakub Krzemiński, Marta Wróblewska, Halina Marchel, Magdalena Romaniec, Paweł Łęgosz et Małgorzata Jakubowska. « Graphene Nanolayers as a New Method for Bacterial Biofilm Prevention : Preliminary Results ». Journal of AOAC INTERNATIONAL 100, n^o 4 (1 juillet 2017) : 900–904. http://dx.doi.org/10.5740/jaoacint.17-0164.

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Abstract Biofilms are microbial communities of surface-attached cells embedded in a self-produced extracellular matrix. They have been found to play a role in a wide variety of infections, including catheter-related urinary tract and bloodstream infections, and, therefore remain a significant source of morbidity and mortality among the world's population. Recently, much attention has been devoted to the prevention of biofilm formation on implant surfaces. Nanomaterials such as graphene, characterized by antibacterial activity and low toxicity to human cells, are promising candidates for biomedical applications. This study investigates the antibacterial efficiency of graphene and specially produced graphene decorated with silver nanoparticles, obtained by one of the methods of printed electronics (spray-coating system). These methods are not only economical, but also enable the printing of layers of various thicknesses on different types of materials, including flexible and nonplanar substrates. The aim of the study was to reveal the ability of graphene and graphene-nanosilver layers to prevent the formation of Staphylococcus epidermidis biofilm on the surface of a Foley catheter.

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Melaiye, Abdulkareem, Zhaohui Sun, Khadijah Hindi, Amy Milsted, Daniel Ely, Darrell H. Reneker, Claire A. Tessier et Wiley J. Youngs. « Silver(I)−Imidazole Cyclophanegem-Diol Complexes Encapsulated by Electrospun Tecophilic Nanofibers : Formation of Nanosilver Particles and Antimicrobial Activity ». Journal of the American Chemical Society 127, n^o 7 (février 2005) : 2285–91. http://dx.doi.org/10.1021/ja040226s.

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Yi, Yueming, Changjin Wang, Xinxin Cheng, Kechuan Yi, Weidong Huang et Haibing Yu. « Biosynthesis of Silver Nanoparticles by Conyza canadensis and Their Antifungal Activity against Bipolaris maydis ». Crystals 11, n^o 12 (23 novembre 2021) : 1443. http://dx.doi.org/10.3390/cryst11121443.

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Silver nanoparticles were biosynthesized from Conyzacanadensis leaf extract with the help of a microwave oven. The UV-vis spectrum showed the maximum absorption at 441 nm, corresponding to the surface plasmon resonance of silver nanoparticles. Transmission electron microscope and scanning electron microscope images showed that the synthesized silver nanoparticles were spherical or near-spherical with an average diameter of 43.9 nm. X-ray diffraction demonstrated nanoparticles with a single-phase cubic structure. As-synthesized silver nanoparticles displayed prominent antifungal activity against Bipolaris maydis. The colony inhibition rate reached 88.6% when the concentration of nanosilver colloid was 100 μL·mL−1 (v/v). At such a concentration, no colony formation was observed on the solid plate. The diameter of the inhibition zone was 13.20 ± 1.12 mm. These results lay the foundation for the comprehensive control of plant pathogens using an environmentally friendly approach.

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Abdelmigid, Hala M., Maissa M. Morsi, Nahed Ahmed Hussien, Amal Ahmed Alyamani et Noha Moslah Al Sufyani. « Comparative Analysis of Nanosilver Particles Synthesized by Different Approaches and Their Antimicrobial Efficacy ». Journal of Nanomaterials 2021 (15 octobre 2021) : 1–12. http://dx.doi.org/10.1155/2021/2204776.

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Silver nanoparticles (AgNPs) were extensively used in different fields worldwide. There is a continued increase in their productions to fulfill various uses. Biological and chemical AgNP syntheses were the most popular mechanisms in this field. Agrowastes are rich in proteins, phenolics, and flavonoids that could act as bioreductant agents in AgNP biological synthesis. The present study was aimed at synthesizing AgNPs via chemical and biological methods using trisodium citrate, pomegranate fruit peel, and coffee ground waste extracts. Moreover, silver nanoparticles were monitored by UV-vis spectroscopy and characterized using zeta potential, size distribution mean, scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FTIR). Four pathogenic bacterial strains (Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and MRSA) were used to assess the antimicrobial effect of the synthesized AgNPs (2, 4, and 8 mg/ml). Results report the successful formation of silver nanoparticles chemically (AgNPs_Chem) and biologically by using pomegranate peel extract (AgNPs_PPE) and coffee ground waste extract (AgNPs_CE) due to the change of color to dark brown that is confirmed by UV-vis sharp absorption spectra at specific wavelengths. Characterization using SEM and XRD revealed their crystalline shape with a mean size of AgNPs _ Chem = 62.75 , AgNPs _ CE = 273.7 nm , and AgNPs _ PPE = 591.9 nm . AgNPs_Chem show higher negativity of zeta potential (−46.7 mV) than AgNPs_CE (−12.6 mV), followed by AgNPs_PPE (−7.98 mV), which had the least stability. All the synthesized AgNPs show antimicrobial potential on all selected strains. However, 8 mg/ml shows the most effective concentration and has more efficiency on K. pneumoniae than others. Overall, the results highlight that the use of agrowastes could be an ecofriendly way to synthesize AgNPs biologically that have the same antimicrobial effect as the chemically synthesized AgNPs.

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Wang, Huili, et Bing Xie. « Study on how nanosilver-based inorganic antibacterial agent functions on biofilm formation of Candida albicans, inside the oral cavity ». Artificial Cells, Nanomedicine, and Biotechnology 44, n^o 6 (13 mai 2015) : 1429–33. http://dx.doi.org/10.3109/21691401.2015.1031907.

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Nahar, M. K., Zarina Zakaria, U. Hashim et Md Fazlul Bari. « Green Synthesis of Silver Nanoparticles Using Momordica Charantia Fruit Extracts ». Advanced Materials Research 1109 (juin 2015) : 35–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.35.

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The synthesis of nanoparticles is in the spotlight in modern nanotechnology. In recent years, the development of competent green chemistry methods for synthesis of metal nanoparticles (NPs) has become a main limelight of researchers. Biological synthesis of nanoparticles using plant extract is currently under exploitation. The first time in this paper we have reported the green synthesis of silver nanoparticles (AgNPs) by reduction of silver nitrate, using fruit extracts of Momordica charantia (bitter melon); commonly found plant in south East Asia. The reaction process for the synthesis of silver nanoparticles is simple, cost-effective, novel, rapid and eco-friendly route using fruit extract of M. charantia plant, which acted as a reducing and stabilizing agent simultaneously at room temperature. Formation of the nanosilver was confirmed by surface Plasmon spectra using UV-Vis spectrophotometer and absorbance peak at 440 nm. Different silver ion concentration and contact times were experimenting in the synthesis of silver nanoparticles. The prepared nanoparticles properties were characterized by UV-Vis.

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AINUR, BEKTURSUNOVA, BOTABAYEV NURZHAN, YERKEBAI GANI et NABIEV DONYOR. « The improvement of bactericidal properties and change of colour characteristics of knitted materials at using nanosilver and carboxymethyl starch ». Industria Textila 73, n^o 01 (5 mars 2022) : 19–26. http://dx.doi.org/10.35530/it.073.01.202054.

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The availability of bactericidal knitted cotton fabrics by processing a biodegradable bactericidal nano composition containing nanoparticles of silver and Na-carboxymethyl starch is studied in this work. The nanocomposite based on Na-carboxymethyl starch and silver nanoparticles were successfully fixed on the surface of knitted cotton fabrics through the formation of links between carboxymethyl groups of carboxymethyl starch and nanosilver, as well as air interlacing between nano composition and material. The analysis of the change in the colour of knitted cotton fabrics after processing them with a solution of the nano composition of silver and Na-carboxymethyl starch showed the stability of the colouristic indicators of the colour during antibacterial treatment. Knitted cotton fabrics treated with the developed nano composition exhibit high antibacterial activity towards gram-positive fungal cultures of Bacillus subtilis, Staphylococcus aureus, and gram-negative Pseudomonas aeruginosa. Consistency of colour and the presence of bacteriostatic properties after repeated washing of knitted cotton fabrics confirms the stability of the antimicrobial properties of reusable fabrics.

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Xiao, Xingzhi, Gang Li, Tingting Liu et Mingfei Gu. « Experimental Study of the Jetting Behavior of High-Viscosity Nanosilver Inks in Inkjet-Based 3D Printing ». Nanomaterials 12, n^o 17 (5 septembre 2022) : 3076. http://dx.doi.org/10.3390/nano12173076.

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Inkjet printing of high-viscosity (up to 105 mPa·s) nanosilver inks is an interesting emerging technology to achieve the 3D fully printed fabrication of electronic products. The highly viscous force of the ink makes it impossible to achieve droplet ejection with the traditional piezoelectric-driven drop-on-demand inkjet method. In this study, a pneumatic needle jetting valve is adopted to provide sufficient driving force. A large number of high-viscosity inkjet printing tests are carried out, and the jetting behavior is recorded with a high-speed camera. Different jetting states are determined according to the recorded images, and the causes of their formation are revealed. Additionally, the effects of the operating pressure, preload angle, and fluid pressure on jetting states are elucidated. Furthermore, the jetting phase diagram is obtained with the characterization of the Reynolds number and the printable region is clarified. This provides a better understanding of high-viscosity inkjet printing and will promote the application of high-viscosity inkjet printing in 3D fully printed electronic products.

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Wekwejt, Marcin, Anna Michno, Karolina Truchan, Anna Pałubicka, Beata Świeczko-Żurek, Anna Maria Osyczka et Andrzej Zieliński. « Antibacterial Activity and Cytocompatibility of Bone Cement Enriched with Antibiotic, Nanosilver, and Nanocopper for Bone Regeneration ». Nanomaterials 9, n^o 8 (3 août 2019) : 1114. http://dx.doi.org/10.3390/nano9081114.

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Bacterial infections due to bone replacement surgeries require modifications of bone cement with antibacterial components. This study aimed to investigate whether the incorporation of gentamicin or nanometals into bone cement may reduce and to what extent bacterial growth without the loss of overall cytocompatibility and adverse effects in vitro. The bone cement Cemex was used as the base material, modified either with gentamicin sulfate or nanometals: Silver or copper. The inhibition of bacterial adhesion and growth was examined against five different bacterial strains along with integrity of erythrocytes, viability of blood platelets, and dental pulp stem cells. Bone cement modified with nanoAg or nanoCu revealed greater bactericidal effects and prevented the biofilm formation better compared to antibiotic-loaded bone cement. The cement containing nanoAg displayed good cytocompatibility without noticeable hemolysis of erythrocytes or blood platelet disfunction and good viability of dental pulp stem cells (DPSC). On the contrary, the nanoCu cement enhanced hemolysis of erythrocytes, reduced the platelets aggregation, and decreased DPSC viability. Based on these studies, we suggest the modification of bone cement with nanoAg may be a good strategy to provide improved implant fixative for bone regeneration purposes.

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Cuong, Do Manh, Hoang Thanh Tung, Hoang Dac Khai, Vu Quoc Luan, Vu Thi Hien, Truong Thi Bich Phuong et Duong Tan Nhut. « Increasing the somatic embryogenesis frequency of Panax vietnamensis Ha et Grushv. by disinfection of leaf explant using nano silver and the addition of nano silver in culture medium ». Vietnam Journal of Biotechnology 18, n^o 3 (28 novembre 2020) : 517–27. http://dx.doi.org/10.15625/1811-4989/18/3/12712.

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Somatic embryo is a developmental method for mass multiplication of valuable medicinal plants. In this study, leaf explants of Ngoc Linh ginseng were disinfected with nano silver at different concentrations and exposure times to eliminate infectious agents and induce embryogenic callus for the production of somatic embryos. The results show that the lowest contamination rate (20.00%) was observed when leaf explants were treated with 0.5 g/L nano silver for 15 minutes while the highest embryogenic callus induction rate (72.22%) and fresh weight (0.77 g) was determined at 0.2 g/L nano silver for 20 minutes. High frequency of somatic embryogenesis formation and germination were occurred on MS medium supplemented 1.0 mg/L 2,4-D; 0.5 mg/L NAA; 0.2 mg/L Kin and 1.6 mg/L nanosilver. After 8 weeks of culture, the number somatic embryos derived from nano silver treated-leaves was increased 2 times than non-treated explants. Addition of 1.0 mg/L NAA and 1.2 mg/L nano silver was showed the highest shoot and root length, root number, fresh and dry weight of plantlets. This research showed that pre-treatment and supplement of nano silver in culture medium is potentially useful for improving embryogenesis frequency, and plantlet formation of Ngoc Linh ginseng cultured in vitro.

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Taghiyari, Hamid R., Dorina Camelia Ilies, Petar Antov, Grama Vasile, Reza Majidinajafabadi et Seng Hua Lee. « Effects of Nanosilver and Heat Treatment on the Pull-Off Strength of Sealer-Clear Finish in Solid Wood Species ». Polymers 14, n^o 24 (16 décembre 2022) : 5516. http://dx.doi.org/10.3390/polym14245516.

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Pull-off strength is an important property of solid wood, influencing the quality of paints and finishes in the modern furniture industry, as well as in historical furniture and for preservation and restoration of heritage objects. The thermal modification and heat treatment of solid wood have been the most used commercial wood modification techniques over the past decades globally. The effects of heat treatment at two mild temperatures (145 and 185 °C) on the pull-off strength of three common solid wood species, i.e., common beech (Fagus sylvatica L.), black poplar (Populus nigra L.), and silver fir (Abies alba Mill.), were studied in the present research work. The specimens were coated with an unpigmented sealer–clear finish based on an organic solvent. The results demonstrated a positive correlation between the density and pull-off strength in the solid wood species. Heat treatment at 145 °C resulted in an increase in the pull-off strength in all three species, due to the formation of new bonds in the cell-wall polymers. Thermal degradation of the polymers at 185 °C weakened the positive effect of the formation of new bonds, resulting in a largely unchanged pull-off strength in comparison with the control specimens. Impregnation with a silver nano-suspension decreased the pull-off strength in beech specimens. It was concluded that density is the decisive factor in determining the pull-off strength, having a significant positive correlation (R-squared value of 0.89). Heat treatment at lower temperatures is recommended, to increase pull-off strength. Higher temperatures can have a decreasing effect on pull-off strength, due to the thermal degradation of cell-wall polymers.

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Dąbrowska-Bouta, Beata, Grzegorz Sulkowski, Mikołaj Sałek, Małgorzata Frontczak-Baniewicz et Lidia Strużyńska. « Early and Delayed Impact of Nanosilver on the Glutamatergic NMDA Receptor Complex in Immature Rat Brain ». International Journal of Molecular Sciences 22, n^o 6 (17 mars 2021) : 3067. http://dx.doi.org/10.3390/ijms22063067.

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Silver nanoparticles (AgNPs) are the one of the most extensively used nanomaterials. The strong antimicrobial properties of AgNPs have led to their use in a wide range of medical and consumer products. Although the neurotoxicity of AgNPs has been confirmed, the molecular mechanisms have not been extensively studied, particularly in immature organisms. Based on information gained from previous in vitro studies, in the present work, we examine whether ionotropic NMDA glutamate receptors contribute to AgNP-induced neurotoxicity in an animal model of exposure. In brains of immature rats subjected to a low dose of AgNPs, we identified ultrastructural and molecular alterations in the postsynaptic region of synapses where NMDA receptors are localized as a multiprotein complex. We revealed decreased expression of several NMDA receptor complex-related proteins, such as GluN1 and GluN2B subunits, scaffolding proteins PSD95 and SynGAP, as well as neuronal nitric oxide synthase (nNOS). Elucidating the changes in NMDA receptor-mediated molecular mechanisms induced by AgNPs, we also identified downregulation of the GluN2B-PSD95-nNOS-cGMP signaling pathway which maintains LTP/LTD processes underlying learning and memory formation during development. This observation is accompanied by decreased density of NMDA receptors, as assessed by a radioligand binding assay. The observed effects are reversible over the post-exposure time. This investigation reveals that NMDA receptors in immature rats are a target of AgNPs, thereby indicating the potential health hazard for children and infants resulting from the extensive use of products containing AgNPs.

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