Articles de revues : « Shell nanofili »

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Craig, Marina, Annika Altskär, Lars Nordstierna et Krister Holmberg. « Bacteria-triggered degradation of nanofilm shells for release of antimicrobial agents ». Journal of Materials Chemistry B 4, n^o 4 (2016) : 672–82. http://dx.doi.org/10.1039/c5tb01274k.

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Wu, Chun-Yan, Zhi-Qiang Pan, You-Yi Wang, Cai-Wang Ge, Yong-Qiang Yu, Ji-Yu Xu, Li Wang et Lin-Bao Luo. « Core–shell silicon nanowire array–Cu nanofilm Schottky junction for a sensitive self-powered near-infrared photodetector ». Journal of Materials Chemistry C 4, n^o 46 (2016) : 10804–11. http://dx.doi.org/10.1039/c6tc03856e.

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Zheng, Ming, Qiu-Xiang Zhu, Xue-Yan Li, Xiao-Min Li et Ren-Kui Zheng. « Magnetic and electrical properties of three-dimensional (La,Pr,Ca)MnO3 nanofilm/ZnO nanorod p–n junctions ». RSC Adv. 4, n^o 62 (2014) : 32622–27. http://dx.doi.org/10.1039/c4ra06302c.

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Excellent room temperature rectification performance and enhanced ferromagnetic phase transition temperature was achieved for the La_0.5Pr_0.17Ca_0.33MnO₃ nanofilm/ZnO nanorod p–n junctions prepared by depositing the La_0.5Pr_0.17Ca_0.33MnO₃ shell layer on the ZnO nanorods.

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Ashaduzzaman, Md, Shu Hei Kai et Masashi Kunitake. « Investigation of Click Reaction at an Oil-Water Interface Using Hydrophobic and Hydrophilic Polymers ». International Letters of Chemistry, Physics and Astronomy 11 (septembre 2013) : 31–39. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.11.31.

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Cu(I)-catalyzed Huisgen click reactions between lipophilic polymer (tri-arm azidofunctionalized polystyrene) and hydrophilic polymer (copolymer of styrene sulfonate sodium and propargyl methacrylate) were investigated and hollow capsules, consisting of composite polymer nanofilms were obtained in chloroform-water biphasic solution. Since the lipophilic polymer, or hydrophilic polymer and copper catalyst were present in the oil or aqueous phase, respectively, the cross-linking reaction proceeded only at the phase interface. The combination of lipophilic and hydrophilic polymers produced hollow capsules consisting of nanofilms with lipophilic core and hydrophilic shell.

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Ashaduzzaman, Md, Shu Hei Kai et Masashi Kunitake. « Investigation of Click Reaction at an Oil-Water Interface Using Hydrophobic and Hydrophilic Polymers ». International Letters of Chemistry, Physics and Astronomy 11 (2 avril 2013) : 31–39. http://dx.doi.org/10.56431/p-96v5at.

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Cu(I)-catalyzed Huisgen click reactions between lipophilic polymer (tri-arm azidofunctionalized polystyrene) and hydrophilic polymer (copolymer of styrene sulfonate sodium and propargyl methacrylate) were investigated and hollow capsules, consisting of composite polymer nanofilms were obtained in chloroform-water biphasic solution. Since the lipophilic polymer, or hydrophilic polymer and copper catalyst were present in the oil or aqueous phase, respectively, the cross-linking reaction proceeded only at the phase interface. The combination of lipophilic and hydrophilic polymers produced hollow capsules consisting of nanofilms with lipophilic core and hydrophilic shell.

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Zhang, Xing Fang, Xin Yan et Feng Shou Liu. « Optical Properties and SERS Activities of Thin Au Half-Shell Nanofilms on Glass and Silicon Substrate ». Advanced Materials Research 898 (février 2014) : 11–14. http://dx.doi.org/10.4028/www.scientific.net/amr.898.11.

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Thin gold hollow half-shell nanostructured films are fabricated by deposited gold over regular arrays of polystyrene nanospheres on glass and silicon substrate respectively in an attempt to evaluate their optical properties and SERS activities. Scanning emission microscopy is used to topographically characterize the nanofilms. Optical spectra taken by UV-vis-NIR spectrometer show that the surface plasmon resonance wavelength of films fabricated on glass is shorter than that fabricated on silicon despite the nanoshell thickness is the same on both substrate, and the SERS intensity excited on silicon is stronger than that on glass because the nanofilms are so thin that the silicon can reflect the SERS signal and excited laser.

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Huang, Qitong, Xiaofeng Lin, Changqing Lin, Yong Zhang, Hanqiang Zhang, Shirong Hu, Chan Wei et Qing-Xiao Tong. « Ultrasensitive-electrochemical sensor for the detection of luteolin in Chrysanthemums and Peanut shells using an Au/Pd/reduced graphene oxide nanofilm ». Analytical Methods 8, n^o 33 (2016) : 6347–52. http://dx.doi.org/10.1039/c6ay01752e.

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ZHANG Xing-fang, 张兴坊, et 闫昕 YAN Xin. « Tunable Plasmonic Properties of Gold Hollow-core Semi-shell Nanofilms ». ACTA PHOTONICA SINICA 42, n^o 2 (2013) : 196–99. http://dx.doi.org/10.3788/gzxb20134202.0196.

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Wen, Peng, Kun Feng, Huan Yang, Xiao Huang, Min-Hua Zong, Wen-Yong Lou, Ning Li et Hong Wu. « Electrospun core-shell structured nanofilm as a novel colon-specific delivery system for protein ». Carbohydrate Polymers 169 (août 2017) : 157–66. http://dx.doi.org/10.1016/j.carbpol.2017.03.082.

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Colie, Maria, Dan Eduard Mihaiescu, Daniela Istrati, Adrian Vasile Surdu, Bogdan Vasile, Nicolae Stanica, Adrian Fudulu et Ecaterina Andronescu. « Synthesis and Characterization of a Core-shell Material Using YBa2Cu3O7-d and Cobalt Ferrite Nanoparticles ». Revista de Chimie 69, n^o 12 (15 janvier 2019) : 3345–48. http://dx.doi.org/10.37358/rc.18.12.6746.

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In this paper we describe the synthesis of a core-shell material using yttrium superconducting ceramic material (YBCO) and cobalt ferrite nanoparticles in order to obtain a nanostructured material with magnetic properties. The advantages of such material aim the selective deposition of nanofilms oriented in magnetic fields. To obtain this core-shell material, the solutions of the nitrates were first obtained by dissolving the salts in demineralised water. The suspension with cobalt ferrite nanoparticles was obtained by co-precipitation method. To obtain YBa2Cu3O7-�- coated magnetic nanoparticles by autocombustion reaction the solutions of nitrates and citric acid were used. The ratio of the metal ions: Y:Ba:Cu was 1:2:3, and between the oxidant and the reducing agent was used a citrate / nitrate mass ratio equal with 0.7. The final material was analyzed by X-ray diffraction (XRD), electronic scanning microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM).

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Ravariu, Cristian, Dan Mihaiescu, Alina Morosan, Bogdan Stefan Vasile et Bogdan Purcareanu. « Sulpho-Salicylic Acid Grafted to Ferrite Nanoparticles for n-Type Organic Semiconductors ». Nanomaterials 10, n^o 9 (9 septembre 2020) : 1787. http://dx.doi.org/10.3390/nano10091787.

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A disadvantage of the use of pentacene and typical organic materials in electronics is that their precursors are toxic for manufacturers and the environment. To the best of our knowledge, this is the first report of an n-type non-toxic semiconductor for organic transistors that uses sulpho-salicylic acid—a stable, electron-donating compound with reduced toxicity—grafted on a ferrite core–shell and a green synthesis method. The micro-physical characterization indicated a good dispersion stability and homogeneity of the obtained nanofilms using the dip-coating technique. The in-situ electrical characterization was based on a point-contact transistor configuration, and the increase in the drain current as the positive gate voltage increased proved the functionality of the n-type semiconductor.

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Pederson, Mark R. « Density-functional-based prediction of a spin-ordered open-shell singlet in an unpassivated graphene nanofilm ». physica status solidi (b) 249, n^o 2 (27 décembre 2011) : 283–91. http://dx.doi.org/10.1002/pssb.201100796.

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Xue, Wei-dong, Wen-jian Wang, Yu-feng Fu, Dong-xu He, Fan-yu Zeng et Rui Zhao. « Rational synthesis of honeycomb-like NiCo2O4@NiMoO4 core/shell nanofilm arrays on Ni foam for high-performance supercapacitors ». Materials Letters 186 (janvier 2017) : 34–37. http://dx.doi.org/10.1016/j.matlet.2016.08.051.

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Pan, Houwen Matthew, Han Yu, Gernot Guigas, Andreas Fery, Matthias Weiss, Volker Patzel et Dieter Trau. « Engineering and Design of Polymeric Shells : Inwards Interweaving Polymers as Multilayer Nanofilm, Immobilization Matrix, or Chromatography Resins ». ACS Applied Materials & ; Interfaces 9, n^o 6 (31 janvier 2017) : 5447–56. http://dx.doi.org/10.1021/acsami.6b13545.

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Vouvoudi, Evangelia C., et Irini D. Sideridou. « Dental Light-Cured Polymer Nanocomposites : A Brief Review of Experimental Results Obtained from the Study of Some Physicochemical Properties ». Journal of Composites and Biodegradable Polymers 2, n^o 1 (5 février 2014) : 46–55. http://dx.doi.org/10.12974/2311-8717.2014.02.01.6.

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This article is a brief review of the experimental results obtained from the study of some physicochemical properties of five dental commercial light-cured nanocomposites: Filtek Supreme XT Body (FSB) and Filtek Supreme XT Translucent (FST), both characterized as nanofill composites, and Grandio (GR), Tetric EvoCeram (TEC) and Protofill-nano (PR) characterized as nanohybrid composites. The properties presented are: volumetric shrinkage due to polymerization, sorption, solubility and volume increase after sorption of composites in water or artificial saliva SAGF® medium for 30 days, flexural strength and modulus after immersion in water or artificial saliva for one or 30 days and finally the dynamic mechanical properties (storage modulus E', loss modulus E'', tand=E''/E' and Tg) determined 1h after light-curing or after immersion in an oral/food simulating liquid (water, artificial saliva or ethanol/water solution 75%vol) for 1 month. It was found via physicochemical properties that the most corrosive solvent is EtOH which heavily affects the polymeric matrix, while water and saliva are smoother media. Moreover, the more rigid and concrete polymeric chains may sustain higher load during mechanical tests, so that the composites with stronger networks shall demonstrate resistance.

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Dai, Jiangdong, Jinsong He, Atian Xie, Lin Gao, Jianming Pan, Xiang Chen, Zhiping Zhou, Xiao Wei et Yongsheng Yan. « Novel pitaya-inspired well-defined core–shell nanospheres with ultrathin surface imprinted nanofilm from magnetic mesoporous nanosilica for highly efficient chloramphenicol removal ». Chemical Engineering Journal 284 (janvier 2016) : 812–22. http://dx.doi.org/10.1016/j.cej.2015.09.050.

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Okumu, Fredrick, et Mangaka Matoetoe. « Electrochemical Characterization of Silver-Platinum Various Ratio Bimetallic Nanoparticles Modified Electrodes ». Journal of Nano Research 44 (novembre 2016) : 114–25. http://dx.doi.org/10.4028/www.scientific.net/jnanor.44.114.

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Silver-platinum (Ag-Pt) bimetallic nanoparticles (NPs) with varying mole fractions (1:1, 1:3 and 3:1) were prepared by co-reduction of hexachloroplatinate and silver nitrate with sodium citrate. Upon successful formation of monometallic and bimetallic (BM) core shell nanoparticles, cyclic voltammetry (CV) was used to characterize the NPs. The drop coated nanofilms on the GC electrode showed characteristic peaks of monometallic Ag NPs; Ag+/Ag0 redox couple as well as the Pt NPs; hydrogen adsorption and desorption peaks. Varying current trends were observed in the BM NPs ratios as; GCE/Ag-Pt NPs 1:3 > GCE/Ag-Pt NPs 3:1 > GCE/Ag-Pt NPs 1:1. Fundamental electrochemical properties such as; diffusion coefficient (D), electroactive surface coverage, electrochemical band gaps and electron transfer coefficient (α) and charge (Q) were assessed using Randles - Sevcik plot. High charge and surface coverage was observed in GCE/Ag-Pt NPs 1:3 accounting for its enhanced current. GCE/Ag-Pt NPs 3:1 showed high diffusion coefficient while GCE/Ag-Pt NPs 1:1 possessed high electron transfer coefficient, which is facilitated by its heterogeneous rate constant relative to other BM NPs ratios. Surface redox reaction was determined as adsorption controlled in all modified GCEs.

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Cheng, Kui, Fan Yang, Dongming Zhang, Jinling Yin, Dianxue Cao et Guiling Wang. « Pd nanofilm supported on C@TiO2 nanocone core/shell nanoarrays : A facile preparation of high performance electrocatalyst for H2O2 electroreduction in acid medium ». Electrochimica Acta 105 (août 2013) : 115–20. http://dx.doi.org/10.1016/j.electacta.2013.05.007.

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Sami, Rokayya, Ebtihal Khojah, Abeer Elhakem, Nada Benajiba, Mahmoud Helal, Nawal Alhuthal, Sana A. Alzahrani, Mona Alharbi et Murthy Chavali. « Performance Study of Nano/SiO2 Films and the Antimicrobial Application on Cantaloupe Fruit Shelf-Life ». Applied Sciences 11, n^o 9 (25 avril 2021) : 3879. http://dx.doi.org/10.3390/app11093879.

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In the current study, novel films with chitosan/nano/SiO2/nisin films and their antimicrobial application on cantaloupe fruit shelf-life have been studied. Novel films were prepared by the addition of 1% chitosan, 1% nano silicon dioxide, and 1% nisin and freeze-dried for the performance study. Physicochemical properties such as tensile strength, optical, and thermal properties with the performance characteristics of the novel films were measured. Coated and uncoated cantaloupes with various coating solutions were stored and chilled at 4 °C in a relative humidity of 70% for up to nine days. The microbial population measurements have been detected every three days. Results show that the fourier transform infrared intensity (FTIR) of nano/SiO2 and with the addition of nisin (nano/SiO2/n) were higher than chitosan (CH) film except in the wavenumber (3150–3750 cm−1) films peaks. Novel nanofilms enhanced tensile strength as well as optical and thermal properties. XRD analysis reported two distinct peak values of 32.08 and 45.99 to correspond to nano/SiO2/n film orientation (7095) and (3316), respectively. Zeta potential values and turbidity were increased, while nano/SiO2 films decreased the hydrophobicity of the film surface by 80.07°. The coating treatments with nano/SiO2 and nano/SiO2/n both reduced the yeast and mold counts 2.49 and 1.92 log CFU/g, respectively, on day nine. In summary, chitosan/nano/SiO2/n novel film improved the functional properties of coating films, and those bio-nanocomposites are effective in food packaging.

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Rana, Ruhul Amin, Md Nurealam Siddiqui, Milan Skalicky, Marian Brestic, Akbar Hossain, Emrul Kayesh, Marek Popov et al. « Prospects of Nanotechnology in Improving the Productivity and Quality of Horticultural Crops ». Horticulturae 7, n^o 10 (22 septembre 2021) : 332. http://dx.doi.org/10.3390/horticulturae7100332.

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Nanotechnology shows high promise in the improvement of agricultural productivity thus aiding future food security. In horticulture, maintaining quality as well as limiting the spoilage of harvested fruit and vegetables is a very challenging task. Various kinds of nanomaterials have shown high potential for increasing productivity, enhancing shelf-life, reducing post-harvest damage and improving the quality of horticultural crops. Antimicrobial nanomaterials as nanofilm on harvested products and/or on packaging materials are suitable for the storage and transportation of vegetables and fruits. Nanomaterials also increase the vitality of the cut flower. Nanofertilizers are target-specific, slow releasing and highly efficient in increasing vegetative growth, pollination and fertility in flowers, resulting in increased yield and improved product quality for fruit trees and vegetables. Formulated nanopesticides are target-specific, eco-friendly and highly efficient. Nanosensors facilitate up-to-date monitoring of growth, plant disease, and pest attack in crop plants under field conditions. These novel sensors are used to precisely identify the soil moisture, humidity, population of crop pests, pesticide residues and figure out nutrient requirements. This review aimed to provide an update on the recent advancement of nanomaterials and their potential uses for enhancing productivity, quality of products, protection from pests and reduction of the postharvest losses of the horticultural crops. This study reveals that nanotechnology could be used to generate cutting-edge techniques towards promoting productivity and quality of horticultural crops to ensure food and nutritional security of ever-increasing population of the world.

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Schafer, Lothar, Yury I. Tarasov, Nina V. Sharonova et Anatoly A. Ischenko. « ULTRAFAST ELECTRON CRYSTALLOGRAPHY AND NANOCRYSTALLOGRAPHY : FOR CHEMISTRY, BIOLOGY AND MATERIALS SCIENCE. PART II. ULTRAFAST ELECTRON NANOCRYSTALLOGRAPHY ». IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, n^o 6 (19 juillet 2017) : 4. http://dx.doi.org/10.6060/tcct.2017606.5609.

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This article shows the development of the Ultrafast Electron Nanocrystallography (UEnC), a specific implementation of Ultrafast Electron Crystallography (UEC), optimized for high sensitivity and high data acquisition efficiency and trained on the quantitative studies of different solid nanostructures with high temporal resolution ranging from pico- to femtoseconds. These achievements have opened up new possibilities for studying the coherent structural dynamics of the nanoparticles. Nanostructures are characterized by a number of unusual properties compared to their bulk counterparts. First of all, this is due to the manifestation of the quantum-size effect and the corresponding relatively-large percentage of structural units of the nanoparticle being on its surface. One of the structural features is the emergence of the so-called nano-crystallographic structure types, which have a tendency to form closed shells and are connected with the appearance of magic numbers in the size distribution. The morphology and lattice parameters of nanocrystals are strongly dependent on the substrate and the surface modification, which results in the contraction, and the formation of twin boundaries due to the relaxation of the surface deformations. The article describes UEnC experiment, the theory and data analysis, and sample preparation. The presented examples include the investigation of the structural dynamics of condensed phase, surfaces, and nanocrystals, the melting dynamics of gold nanoparticles and direct observation of coherent optical phonons generation in nanofilms. The results of several internationally renowned research groups are included and cited.Forcitation:Schafer L., Tarasov Yu.I., Sharonova N.V., Ischenko A.A. Ultrafast electron crystallography and nanocrystallography: for chemistry, biology and materials science. Part II. Ultrafast electron nanocrystallography. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 4-27.

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Sami, Rokayya, Ebtihal Khojah, Mahmoud Helal, Abeer Elhakem, Nada Benajiba, Amina A.M. Al-Mushhin, Mohammed Saeed Alkaltham, Ahmad Mohammad Salamatullah, Kambhampati Vivek et N. Fouda. « Effects of Coating by Chitosan, TiO₂ Nanoparticles, and Sodium Tripolyphosphate as Crosslinker on Stored Cucumber Fruits ». Journal of Biobased Materials and Bioenergy 15, n^o 5 (1 octobre 2021) : 598–605. http://dx.doi.org/10.1166/jbmb.2021.2096.

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Cucumber fruit contains essential nutrients and fibers and is used widely in salads dressing. Scarce research is available on its storage with nanoparticles and chitosan combined effects. Hence, the objective of this current research was to evaluate some Physico-chemical properties and microbial activity after coating with the combination of chitosan, TiO2 nanoparticles, and sodium tripolyphosphate to enhance the cucumbers storability and prolong the shelf-life. The cucumbers fruits were divided into four groups and dipped into several coating solutions for 10 minutes such as distilled water (Cu-uncoated), chitosan 1% (Cu-Chitosan), chitosan 1%, titanium dioxide nanoparticles 1% (Cu-Chitosan-TDN), and chitosan 1%, titanium dioxide nanoparticles 1%, sodium tripolyphosphate 2% (Cu-Chitosan-TDN-ST), respectively. The cucumber samples were then air-dried at ambient temperature and chilled to 10 °C for storage and evaluation for every seven days until three weeks. Cu-uncoated had the highest weight loss with a value of 5.15%, followed by Cu-Chitosan 4.11% while Cu-Chitosan-TDN and Cu-Chitosan-TDN-ST reported the least weight loss of (3.43% and 3.01%, respectively) after 7 days of the storage period. The results reported that the firmness of the samples was found to be decreased during the whole storage time except in the treatments Cu-Chitosan-TDN-ST and Cu-Chitosan-TDN in which it was noticed to be better in firmness after 21 days of storage (55.12 N/mm and 50.67 N/mm), respectively. Total soluble solids were lower in the coated cucumbers compared with the uncoated samples. Titratable acidity of Cu-Chitosan-TDN-ST 0.26% treated sample increased more as compared with Cu-Chitosan-TDN 0.24% samples at the end of the storage period. The highest increase in pectin content was recorded for Cu-Chitosan-TDN samples 0.042 g/100 g on the 21st day. Nano-coating with the combination of chitosan declared the dietary fiber content changes rate than in samples with the addition of sodium tripolyphosphate. Besides, the antimicrobial activity of the chitosan/nanofilms has been improved with the addition of sodium tripolyphosphate as crosslinker 3.67 CFU/g on the 21st day of storage. Thus, nano-coating with the combination of sodium tripolyphosphate has proven to be efficient method in extending the shelf-life of cucumber samples.

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Ruiz-Gonzalez, Antonio, Harriet Kempson et Jim Haseloff. « In Vivo Sensing of pH in Tomato Plants Using a Low-Cost and Open-Source Device for Precision Agriculture ». Biosensors 12, n^o 7 (23 juin 2022) : 447. http://dx.doi.org/10.3390/bios12070447.

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The development of sensing devices for precision agriculture is crucial to boost crop yields and limit shortages in food productions due to the growing population. However, current approaches cannot provide direct information about the physiological status of the plants, reducing sensing accuracy. The development of implanted devices for plant monitoring represents a step forward in this field, enabling the direct assessment of key biomarkers in plants. However, available devices are expensive and cannot be used for long-term applications. The current work presents the application of ruthenium oxide-based nanofilms for the in vivo monitoring of pH in plants. The sensors were manufactured using the low-cost electrodeposition of RuO2 films, and the final device could be successfully incorporated for the monitoring of xylem sap pH for at least 10 h. RuO2 nanoparticles were chosen as the sensing material due to its biocompatibility and chemical stability. To reduce the noise rates and drift of the sensors, a protective layer consisting of a cellulose/PDMS hybrid material was deposited by an aerosol method (>GBP 50), involving off-the-shelf devices, leading to a good control of film thickness. Nanometrically thin films with a thickness of 80 nm and roughness below 3 nm were fabricated. This film led to a seven-fold decrease in drift while preserving the selectivity of the sensors towards H+ ions. The sensing devices were tested in vivo by implantation inside a tomato plant. Environmental parameters such as humidity and temperature were additionally monitored using a low-cost Wio Terminal device, and the data were sent wirelessly to an online server. The interactions between plant tissues and metal oxide-based sensors were finally studied, evidencing the formation of a lignified layer between the sensing film and xylem. Thus, this work reports for the first time a low-cost electrochemical sensor that can be used for the continuous monitoring of pH in xylem sap. This device can be easily modified to improve the long-term performance when implanted inside plant tissues, representing a step forward in the development of precision agriculture technologies.

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Li, Jiangang, Xiao Lei, Jianhua Ding, Zhixiang Gao et Hua Wang. « Curling behavior of free-standing nanofilms driven by surface stress : core-shell model ». European Physical Journal Applied Physics, 29 septembre 2022. http://dx.doi.org/10.1051/epjap/2022220185.

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A continuum theoretical model for describing curling behavior of free-standing nanofilms was given in this paper. Surface stress, surface elasticity (surface Young’s modulus), surface slice thickness and anisotropic deformation were considered. For a nanofilm with only several nanometers, curling behavior is apt to be more common than isotropic bending behavior. The curling behavior is an anisotropic problem and is different from isotropic bending behavior as Stoney formula interprets. The isotropic bending behavior makes nanofilm to become a ball-like object while curling behavior makes nanofilm to become a tube-like object. If surface elasticity is imbalance, surface stress sum will bend nanofilms and surface stress difference expands nanofilms. The balance surface elasticity and surface stress induces isotropic elongation deformation despite the anisotropic shape of nanotubes. If surface elasticity is imbalance, the anisotropic elongation deformation in tangential and cylindrical directions appears.

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Nikoobakht, Babak, Aaron C. Johnston-Peck, David Laleyan, Ping Wang et Zetian Mi. « Surface-directed ZnGa2O4 and β-Ga2O3 nanofins coated with a non-polar GaN shell based on the Kirkendall effect ». CrystEngComm, 2021. http://dx.doi.org/10.1039/d1ce00744k.

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Zhang, Liangqi, Ke Liu, Suo Tang, Wen Luo, Jie Zhao, Hao Zhang et Tong-Pu Yu. « Generation of isolated and polarized γ-ray pulse by few-cycle laser irradiating a nanofoil ». Plasma Physics and Controlled Fusion, 1 août 2022. http://dx.doi.org/10.1088/1361-6587/ac85a7.

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Abstract An isolated ultra-short γ-ray pulse is a unique tool for measuring ultrafast-physics process, such as imaging of intra-nuclear dynamics and inner-shell electron dynamics. Here, we propose an all-optical efficient scheme for generating isolated ultra-short γ-ray pulse from a laser-driven nanofoil. When a few-cycle circularly polarized laser pulse with an intensity of 10 22 W/cm 2 irradiates a nanofoil, the electrons in the nanofoil are pushed forward collectively, forming a single relativistic electron sheet (RES) with the charge of nC. The electrons are substantially accelerated to high energies by the super-ponderomotive force of the laser. Then a counter-propagating laser pulse with a peak intensity of 10 21 W/cm 2 collides with the RES, resulting in the generation of an isolated sub-femtosecond γ-ray pulse via nonlinear Compton scattering. The effects of laser polarization on the polarization degree of γ-rays is investigated by using a proof-of-principle calculation. It is shown that a highly-polarized isolated γ-ray pulse with the cut-off energy of 100 MeV can be eventually generated in a head-on colliding configuration when the scattering laser is a linearly polarized laser. Such an isolated ultra-short polarized γ-ray source would provide critical applications in high energy physics, laboratory astrophysics and nuclear physics.

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Wypij, Magdalena, Joanna Trzcińska-Wencel, Patrycja Golińska, Graciela Dolores Avila-Quezada, Avinash P. Ingle et Mahendra Rai. « The strategic applications of natural polymer nanocomposites in food packaging and agriculture : Chances, challenges, and consumers’ perception ». Frontiers in Chemistry 10 (10 janvier 2023). http://dx.doi.org/10.3389/fchem.2022.1106230.

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Natural polymer-based nanocomposites have received significant attention in both scientific and industrial research in recent years. They can help to eliminate the consequences of application of petroleum-derived polymeric materials and related environmental concerns. Such nanocomposites consist of natural biopolymers (e.g., chitosan, starch, cellulose, alginate and many more) derived from plants, microbes and animals that are abundantly available in nature, biodegradable and thus eco-friendly, and can be used for developing nanocomposites for agriculture and food industry applications. Biopolymer-based nanocomposites can act as slow-release nanocarriers for delivering agrochemicals (fertilizers/nutrients) or pesticides to crop plants to increase yields. Similarly, biopolymer-based nanofilms or hydrogels may be used as direct product coating to extend product shelf life or improve seed germination or protection from pathogens and pests. Biopolymers have huge potential in food-packaging. However, their packaging properties, such as mechanical strength or gas, water or microbial barriers can be remarkably improved when combined with nanofillers such as nanoparticles. This article provides an overview of the strategic applications of natural polymer nanocomposites in food and agriculture as nanocarriers of active compounds, polymer-based hydrogels, nanocoatings and nanofilms. However, the risk, challenges, chances, and consumers’ perceptions of nanotechnology applications in agriculture and food production and packaging have been also discussed.

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Gvozdenko, A. A., S. A. Siddiqui, A. V. Blinov, A. B. Golik, A. A. Nagdalian, D. G. Maglakelidze, E. N. Statsenko et al. « Synthesis of CuO nanoparticles stabilized with gelatin for potential use in food packaging applications ». Scientific Reports 12, n^o 1 (27 juillet 2022). http://dx.doi.org/10.1038/s41598-022-16878-w.

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AbstractIn the present study, a method for the synthesis of gelatin-stabilized copper oxide nanoparticles was developed. Synthesis was carried out by direct chemical precipitation. Copper sulfate, chloride, and acetate were used as precursors for the copper oxide synthesis. Gelatin was used as a stabilizer. It was found that the formation of monophase copper oxide II only occurred when copper acetate was used as a precursor. Our results showed that particles of the smallest diameter are formed in an aqueous medium (18 ± 6 nm), and those of th largest diameter—in an isobutanol medium (370 ± 131 nm). According to the photon correlation spectroscopy data, copper oxide nanoparticles synthesized in an aqueous medium were highly stable and had a monomodal size distribution with an average hydrodynamic radius of 61 nm. The study of the pH effect on the colloidal stability of copper oxide nanoparticles showed that the sample was stable in the pH range of 6.8 to 11.98. A possible mechanism for the pH influence on the stability of copper oxide nanoparticles is described. The effect of the ionic strength of the solution on the stability of the CuO nanoparticles sol was also studied, and the results showed that Ca2+ ions had the greatest effect on the sample stability. IR spectroscopy showed that the interaction of CuO nanoparticles with gelatin occurred through the hydroxyl group. It was found that CuO nanoparticles stabilized with gelatin have a fungicidal activity at concentration equivalent 2.5 · 10−3 mol/L and as a material for food nanopackaging can provide an increase in the shelf life of products on the example of strawberries and tomatoes. We investigated the possibility of using methylcellulose films modified with CuO nanoparticles for packaging and storage of hard cheese “Holland”. The distribution of CuO nanoparticles in the methylcellulose film was uniform. We found that methylcellulose films modified with CuO nanoparticles inhibited the growth and development of QMAFAM, coliforms, yeast and mold in experimental cheese sa mples. Our research has shown that during the cheese storage in thermostat at 35 ± 1 °C for 7 days, CuO nanoparticles migrated to the product from the film. Nevertheless, it is worth noting that the maximum change in the concentration of copper in the experimental samples was only 0.12 µg/mg, which is not a toxic concentration. In general, the small value of migration of CuO nanoparticles confirms the high stability of the developed preparation. Our results indicated that the CuO nanoparticles stabilized with gelatin have a high potential for use in food packaging – both as an independent nanofilm and as part of other packaging materials.

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Alexandrov, Alexander A., Mariya N. Mayakova, Valery V. Voronov, Daria V. Pominova, Sergey V. Kuznetsov, Alexander E. Baranchikov, Vladimir K. Ivanov, Elena I. Lysakova et Pavel P. Fedorov. « Синтез ап-конверсионных люминофоров на основе фторида кальция ». Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 22, n^o 1 (20 mars 2020). http://dx.doi.org/10.17308/kcmf.2020.22/2524.

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Исследование посвящено созданию люминофора на основе фторида кальция, легированного редкоземельными элементами: 5% Yb, 1% Er, с использованием методики синтеза из раствора в расплаве. В качестве растворителя использован нитрат натрия NaNO3, в качестве фторирующего агента – фторид натрия NaF. Полученные образцы охарактеризованы методами рентгенофазового анализа, рентгеноспектрального микроанализа, растровой электронной микроскопии и люминесцентной спектроскопии.В ходе работы исследовано влияние параметров синтеза на фазовый состав и морфологию частиц. Было установлено, что для формирования однофазных образцов – твёрдых растворов на основе фторида кальция – необходимо проводить синтез при температуре не ниже 400 °C, оптимальное время выдержки составило 3 ч. Установлен состав полученных образцов, он отличается от номинального и может быть записан как Ca0.88(Yb, Er)0.06Na0.06F2. 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