Micro & Nano Letters最新文献

{"title":"Influence of the Chromium Content on the Characteristics of the Matrix, the Tantalum Carbides Population, and the Hardness of Cast Co(Cr)-0.4C-6Ta Alloys","authors":"P. Berthod, Merzouk Bouaraba, Junfu Cai","doi":"10.3390/micro3010017","DOIUrl":"https://doi.org/10.3390/micro3010017","url":null,"abstract":"The mechanical and chemical behaviors of cast cobalt-base superalloys are governed by the carbides and by a reactive element, which is often chromium. The content of this later element, which is efficient in resisting hot oxidation and also hot corrosion, may have consequences on the melting temperature, microstructure, and mechanical properties at high temperatures and at room temperature. Seemingly, the effect of chromium content on the microstructure and properties of cast equi-axed Co-Cr-Ta-C superalloys containing TaC as single reinforcing carbide and in high-enough quantities to achieve a high level of creep resistance has not been the subject of previous investigations. The present work is devoted to the exploration of this influence of Cr content on the as-cast microstructure of a model alloy in this category, as well as on its microstructure transformations at high temperatures. The work aims to help rate the Cr content to achieve the best characteristics in machinability and high-temperature properties. This is of great importance for fabricability (production cost) and sustainability in service (long enough lifetime performance). A series of six alloys derived from a rather well-known alloy and presenting various Cr contents were thus elaborated by casting. Their microstructures were investigated in their as-cast state as well as in an aged state resulting from a 4-day stage at 1400 K. Vickers indentation was also carried out to study how hardness may evolve with Cr content. It was seen that the higher the Cr content, the lower the solidus temperature, the coarser the TaC population, the harder the alloy, and the higher the risk of brittleness. In order to reach the best compromise, the preferred Cr weight content range, as identified by this work, is 20–30%; indeed, for such Cr contents: (1) the matrix is austenitic, then dense, and then hard and not brittle, and thus is mechanically resistant and tough; (2) the TaC carbides are script-shaped and resistant against morphology changes at high temperatures, and thus efficiently preserve interdendritic cohesion for a long time, and, consequently, (3) the alloys are machinable, have expected good toughness, and can be resistant against creep deformation as well as oxidation and corrosion at high temperatures thanks to the Cr content, allowing for chromium-forming behavior.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"59 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77249497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluorescence Sensing of Some Important Nitroaromatic Compounds by Using Polyaniline Ag Composite","authors":"S. Ture, Shruthy D. Pattathil, Bertrand Zing Zing, V. Abbaraju","doi":"10.3390/micro3010016","DOIUrl":"https://doi.org/10.3390/micro3010016","url":null,"abstract":"Conducting polymers (CPs) have contributed significantly to the field of sensing. The sensing of nitroaromatic compounds by fluorescence has recently gained more attention due to its sensitivity and selectivity. In this study, polyaniline (PANI) was functionalized by forming a polyaniline-Ag (PANI-Ag) composite and used as a fluorophore for sensing. The nitro groups present in nitroaromatic compounds (NACs) such as 2,4,6-trinitrophenol (picric acid-TNP) and Dinitrobenzene (DNB) act as electron-accepting molecules and quench the fluorescence of polymer chains by showing an amplified quenching effect in which trace amounts of electron-accepting NACs quench emissions of several fluorophore units. The PANI-Ag composite synthesized by interfacial polymerization was analyzed using UV-vis spectroscopy and Fourier-transform infrared (FTIR) spectroscopy for determination of molecular structure; X-ray powder diffraction (XRD) and scanning electron microscopy (SEM/EDAX) for its morphology, which is cubic crystalline silver; and thermogravimetric analysis (TGA) for the thermal stability. The fluorescence quenching mechanism was deduced from the Stern–Volmer plot. The quenching constant value (Ksv) obtained from the Stern–Volmer (S–V) plot was found to be Ksv = 0.1037 × 106 M−1 (TNP) and Ksv = 0.161 × 104 M−1 (DNB). The plot shows a single mechanism with formation of an exciplex complex for TNP with a photoinduced electron transfer (PET) mechanism. The limit of detection (LOD) is found to be TNP = 5.58 × 10−7 M, whereas DNB = 23.30 × 10−6 M shows that the PANI-Ag composite is a potential fluorophore for sensing of nitroaromatic compounds in trace levels.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"50 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86106767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel green synthesis of tin nanoparticles by medicinal plant: Chemical characterization and determination of cytotoxicity, cutaneous wound healing and antioxidant properties","authors":"Miaoqing Shu,&nbsp;Behnam Mahdavi,&nbsp;Aiste Balčiūnaitienė,&nbsp;Samaneh Goorani,&nbsp;Amir Ali Mahdavi","doi":"10.1049/mna2.12157","DOIUrl":"https://doi.org/10.1049/mna2.12157","url":null,"abstract":"<p>In the present study, tin nanoparticles were green-synthesized using the aqueous extract of <i>Foeniculum vulgare</i> leaf aqueous extract. The synthesized SnNPs (tin nanoparticles) were characterized by analytical techniques including EDX (energy dispersive X-ray), FE-SEM (field emission scanning electron microscopy), XRD (X-ray diffraction), UV–vis and FT-IR (Fourier transform-infrared). The cytotoxicity activity of SnNPs was evaluated using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The nanoparticles were formed in a spherical shape in the range size of 26.45–38.53 nm. In the antioxidant test, the IC50 of <i>F. vulgare</i>, SnNPs@FV (Sn nanoparticles@ <i>F. vulgare</i>) and BHT (butylated hydroxytoluene) against DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals were 384, 119 and 71 µg/mL, respectively. In the cellular and molecular part of the recent study, the treated cells with SnNPs@FV were assessed by MTT assay for 48h about the cytotoxicity property on normal HUVEC (human umbilical vein endothelial cells) cell line. In vivo experiment, SnNPs@FV ointment significantly decreased (<i>p</i> ≤ 0.01) the wound area, total cells, neutrophil and lymphocyte and notably increased (<i>p</i> ≤ 0.01) the wound contracture, vessel, hydroxyl proline, hexosamine, hexuronic acid and fibrocyte compared to other groups in rats. Further clinical trials are necessary for confirmation of these remedial properties of SnNPs@FV in humans.</p>","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"18 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/mna2.12157","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50135971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microplastics in Freshwater River in Rio de Janeiro and Its Role as a Source of Microplastic Pollution in Guanabara Bay, SE Brazil","authors":"Thiago L. Drabinski, Diego G. de Carvalho, C. Gaylarde, Marcos F. P. Lourenço, W. Machado, E. M. da Fonseca, A. L. D. da Silva, J. A. Baptista Neto","doi":"10.3390/micro3010015","DOIUrl":"https://doi.org/10.3390/micro3010015","url":null,"abstract":"In the present research, the occurrence of contamination by microplastics in the water column was investigated in 15 sample sites along the rivers Guapimirim, Macacu and Maracanã—important rivers that flow into Guanabara Bay, a very polluted estuarine environment in Brazil. The correctidentified polymers were manually counted and classified as to their morphology and color using a binocular stereomicroscope and were characterized by ATR-FTIR spectroscopy. The total mean abundance of particles was 3651.5 items m−3, ranging from 3.6 to 51,166.5 items m−3. Plastic debris was identified in all samples, with a predominance of fibers (67.3%). Polyethylene, polyester fiber and high-density polyethylene (50%) were the major polymers, and the main colors were transparent followed by black and blue in all the water bodies studied. The highest quantities of microplastics were found in the Maracanã River. The figures show that microplastic concentrations are correlated to the level of urbanization.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"259 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77085214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Barrier Performance of Spray Coated Cellulose Nanofibre Film","authors":"K. Shanmugam, N. Chandrasekar, R. Balaji","doi":"10.3390/micro3010014","DOIUrl":"https://doi.org/10.3390/micro3010014","url":null,"abstract":"Cellulose nanofibre (CNF) is the sustainable nanomaterial used for developing high-performance barrier materials that are renewable, recyclable, and biodegradable. The CNF film has very low oxygen permeability; however, its water vapor permeability is significantly higher than that of conventional packaging plastics. The fabrication method influences their barrier properties of the film. A spray-coating CNF on a stainless-steel plate was developed to form a compact film with two unique surfaces, namely a smooth layer on the base side and rough layer on the free side. It improves both the ease of preparation of the film and reduces the water vapour permeability via tailoring the basis weight and thickness of the film through simple adjusting CNF content in the suspension. The air permanence of the film from 1.0 wt.% to 2.0 wt.% CNF suspension is less than 0.003 µm/Pa·S confirming that is an impermeable film and proves a good packaging material. SEM, optical profilometry, and AFM revealed that the spray-coated surface was smooth and glossy. For sprayed CNF films with basis weight between 86.26 ± 13.61 and 155.85 ± 18.01 g/m2, WVP were ranged from 6.99 ± 1.17 × 10−11 to 4.19 ± 1.45 × 10−11 g/m·Pa·S. In comparison, the WVP of 100 g/m2 vacuum filtered CNF film was 5.50 ± 0.84 × 10−11 g/m·Pa·S, spray-coated film (of 96.6 g/m2) also show similar permeability at around 5.34 ± 0.603 × 10−11 g/m·Pa·S. The best performance was achieved with spraying of 2.0 wt.% CNF and a water vapour permeability of 3.91 × 10−11 g/m·s·Pa. Spray coated CNF film is impermeable against air and water vapour and a potential alternative to synthetic plastics.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"88 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88951369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology and structure evolution of multilayered Ge/Si quantum dots grown by magnetron sputtering","authors":"Qijiang Shu,&nbsp;Pengru Huang,&nbsp;Xicheng Zhang,&nbsp;Linjing Yang,&nbsp;Donghai Ye,&nbsp;Li Yang,&nbsp;Hongxing Liu,&nbsp;Lei Chen","doi":"10.1049/mna2.12158","DOIUrl":"https://doi.org/10.1049/mna2.12158","url":null,"abstract":"<p>The authors prepared multilayered Si-based Ge quantum dots (Ge/Si QDs) by using the magnetron sputtering technique and reported the corresponding morphology evolution by atomic force microscope (AFM), scanning electron micrograph (SEM), X-ray photoelectron spectroscopy (XPS), Raman and X-ray diffraction (XRD) tests. The increased temperature can improve the Si-isolated-layer crystallinity and Ge atom mobility to increase the density, size, and spatial distribution uniformity of top-layer QDs. The morphology and vertical correlation between the layers of QDs at different temperatures exhibited different phenomena or laws, and had been explained in this paper. The authors’ work made it possible to control the quality of multilayer QDs by high-rate deposition technology and laid a foundation for the industrial production of multilayer QDs in the future.</p>","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"18 2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/mna2.12158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50117170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polyaniline Hybrids with Biological Tissue, and Biological Polymers as Physiological—Electroactive Materials","authors":"M. Ichikawa, M. Otaki, H. Goto","doi":"10.3390/micro3010013","DOIUrl":"https://doi.org/10.3390/micro3010013","url":null,"abstract":"A sprout/polyaniline was synthesized via the chemical oxidative polymerization of aniline in the presence of natural sprout, based on a concept of cyborg plant composite. The composite consisted of both polyaniline and plants. The chemical structure was confirmed by infrared absorption spectroscopy measurements. Optical microscopy observation revealed that polyaniline was deposited into the micro-tissue of the sprout to form the conductive polymer bio-composite. Micro-optical fiber functions for the composite were visually confirmed. Furthermore, the sprout/polyaniline based organic diode exhibited an avalanche breakdown phenomenon. Next, a fucoidan/polyaniline composite as a physiological active material/conducting polymer composite was prepared. This composite showed good film-forming ability, electrochromism, and a micro-porous surface. This paper reports the preparation of conducting polymer composites with a combination of bio-tissue and bio-substance for the creation of bio-based electrically active organized architecture.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"39 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85821717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Vitro Cell Response to Strontium/Magnesium-Doped Calcium Phosphate Nanoparticles","authors":"K. Kostka, S. Hosseini, M. Epple","doi":"10.3390/micro3010012","DOIUrl":"https://doi.org/10.3390/micro3010012","url":null,"abstract":"Calcium phosphate nanoparticles are highly biocompatible and biodegradable in bone regeneration. On the other hand, strontium and magnesium enhance the formation of bone. The substitution of calcium by strontium and magnesium is an efficient way to improve the biological properties of calcium phosphate-based biomaterials. Strontium-doped calcium phosphate nanoparticles and magnesium-doped calcium phosphate nanoparticles with degrees of cation substitution of 5, 10, 15, and 20 mol% with respect to calcium were prepared by precipitation, followed by surface functionalization with polyethyleneimine (PEI, cationic) or carboxymethylcellulose (CMC, anionic). The nanoparticles were characterized by dynamic light scattering (DLS), zeta potential measurement, scanning electron microscopy (SEM), atomic absorption spectrometry (AAS), energy dispersive X-ray analysis (EDX), and X-ray powder diffraction (XRD). The particles were approximately spherical (diameter 40–70 nm). The addition of magnesium and strontium considerably decreased the internal crystallinity, i.e., the doped particles were almost X-ray amorphous. The cell-biological effects were assessed on three different cell lines, i.e., HeLa cells, MG63 cells, and MC3T3 cells. Cell viability tests (MTT) showed a low cytotoxicity, the alkaline phosphatase (ALP) activity was strongly increased, and the nanoparticles were taken up well by the three cell lines.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"109 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86007060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphene Formation through Spontaneous Exfoliation of Graphite by Chlorosulfonic Acid: A DFT Study","authors":"Alfredo Bol-Arreba, Isabel G. Ayala, N. A. Cordero","doi":"10.3390/micro3010011","DOIUrl":"https://doi.org/10.3390/micro3010011","url":null,"abstract":"Using exfoliating agents is one of the most promising ways for large-scale production of liquid dispersed graphenic materials from graphite. Therefore, it is crucial to know the reason why some molecules have a larger exfoliating power than others. The highest reported experimental yield for the liquid phase single-surfactant spontaneous exfoliation of graphite, i.e., without sonication, has been obtained using chlorosulfonic acid. The ability of this acid to disperse graphite is studied within the framework of Density Functional Theory (DFT). Equilibrium configurations, electron transfers, binding energies, and densities of states are presented for two acid concentrations and for two situations: adsorption (on monolayer and bilayer graphene) and intercalation (in between simple hexagonal and Bernal-stacked bilayer graphene). Experimental exfoliation power and dispersion stability are explained in terms of charge transfer—the largest found among several studied exfoliating and surfactant agents—facilitated by the good geometrical matching of chlorosulfonic acid molecules to constituent carbon rings of graphene. This matching is in the origin of the tendency toward adsorption of chlorosulfonic acid molecules on graphene monolayers when they separate, originating the charging of the monolayers that precludes their reaggregation.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"42 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75362724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chitosan/Hydroxyapatite Scaffolds with P28 as a Promising Osteoinductive Scaffold for Bone Healing Applications","authors":"Farah Alwani Azaman, F. Daubiné, Amélie Lebatard, Margaret Brennan Fournet, D. Devine","doi":"10.3390/micro3010010","DOIUrl":"https://doi.org/10.3390/micro3010010","url":null,"abstract":"Despite bone’s inherent ability to heal, large bone defects remain a major clinical concern. This study proposes an off-the-shelf treatment combining chitosan/hydroxyapatite (CS/HAp) scaffolds, covalently linked with either bone morphogenetic protein-2 (BMP-2) or its related peptide P28 via a UV crosslinking process. Although covalently binding the growth factors was reported as a great alternative to the conventionally physical adsorption and encapsulation methods, this method presents the risk of altering the molecular activity and interaction of the growth factors. Therefore, alkaline phosphatase (ALP) activity and alizarin red staining (ARS) with a quantitative cetylpyridinium chloride (CPC) assay were conducted to validate that our photo-crosslinking fabrication method did not interfere with the functionality of the growth factors. The ALP activity of C2C12 with 100 µg/mL P28 was found to be comparable to 0.5 µg/mL BMP-2 after two weeks, where 0.001 U/mL was recorded for both treatments. The C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds also showed an increased ALP activity compared to the negative control. ARS-CPC assay presented the highest optical density in 0.3 µg/mL BMP-2 and 50 µg/mL P28, while the highest intensity of ARS was observed in C2C12 cultured with CS/HAp/BMP-2 and CS/HAp/P28 scaffolds compared to the negative controls. The osteoconductive capability of this delivery system was then investigated through a rat femoral condyle defect model, where the new bone mineral density and the bone volume increased for all CS/HAp scaffolds compared to the collagen sponge control treatment. The histological assessment showed a favourable bone regeneration efficacy of the CS/HAp/P28 compared to the CS/HAp/BMP-2 treatment, thus showing the use of CS/HAp scaffolds with P28 as a promising osteoinductive scaffold for bone healing applications.","PeriodicalId":18398,"journal":{"name":"Micro & Nano Letters","volume":"34 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86921324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}