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891.
Magneto‐Thermal Metrics Can Mirror the Long‐Term Intracellular Fate of Magneto‐Plasmonic Nanohybrids and Reveal the Remarkable Shielding Effect of Gold
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François Mazuel Ana Espinosa Guillaume Radtke Matthieu Bugnet Sophie Neveu Yoann Lalatonne Gianluigi A. Botton Ali Abou‐Hassan Claire Wilhelm 《Advanced functional materials》2017,27(9)
Multifunctional nanoparticles such as magneto‐plasmonic nanohybrids are rising theranostic agents. However, little is yet known of their fate within the cellular environment. In order to reach an understanding of their biotransformations, reliable metrics for tracking and quantification of such materials properties during their intracellular journey are needed. In this study, their long‐term (one month) intracellular fate is followed within stem‐cell spheroids used as tissue replicas. A set of magnetic (magnetization) and thermal (magnetic hyperthermia, photothermia) metrics is implemented to provide reliable insightsinto the intracellular status. It shows that biodegradation is modulated by the morphology and thickness of the gold shell. First a massive dissolution of the iron oxide core (nanoflower‐like) is observed, starting with dissociation of the multigrain structure. Second, it is demonstrated that an uninterrupted gold shell can preserve the magnetic core and properties (particularly magnetic hyperthermia). In addition to the magnetic and thermal metrics, intracellular high‐resolution chemical nanocartography evidences the gradual degradation of the magnetic cores. It also shows different transformation scenarios, from the release of small gold seeds when the magnetic core is dissolved (interesting for long‐term elimination) to the protection of the magnetic core (interesting for long‐term therapeutic applicability). 相似文献
892.
Cu2+ and Ni2+ complexes of chitosan/poly(vinyl amine) (CS/PVAm) composites were prepared. The metal-CS/PVAm complexes were characterized by FT-IR spectroscopy, SEM-EDX, X-ray diffraction (XRD), and magnetic moment determination. FT-IR spectra of the metal-CS/PVAm complexes showed the characteristic bands of anhidroglucose unit were affected by the metal complexation, and new bands assigned to Me–N and Me-O bonds were observed. SEM images of the surface of metal-composite complexes show the influence of metal ion on the morphology of the complexes, the strong binding of Cu2+ and Ni2+, involving most of the amino groups, leading to a dense surface structure. The chemical composition on the surface of metal-CS/PVAm complexes was determined from EDX measurements. XRD provided information about the amorphous or crystalline nature of the composite and metal-composite complexes. Using magnetic susceptibility method, the oxidation degree of metal ions from the polymer phase, the homogeneous distribution of the ligand groups from the volume of the CS/PVAm beads, and the existence of the antiferromagnetic interactions between the metal ions were determined. 相似文献
893.
Discrimination of Olive Oil by Cultivar,Geographical Origin and Quality Using Potentiometric Electronic Tongue Fingerprints 总被引:1,自引:0,他引:1
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Fatma Souayah Nuno Rodrigues Ana C. A. Veloso Luís G. Dias José A. Pereira Souheib Oueslati António M. Peres 《Journal of the American Oil Chemists' Society》2017,94(12):1417-1429
Legal regulations are set for protecting claims regarding olive oil geographical denomination. When meteorological or agroecological factors similarly affect different regions, the origin identification is a challenging task. This study demonstrated the use of a potentiometric electronic tongue coupled with linear discriminant analysis to discriminate the geographical origin of monovarietal Tunisian olive oil produced from local cv Chemlali (Kairouan, Sidi Bouzid or Sfax regions) and cv Sahli (Kairouan, Mahdia or Sousse regions). The potentiometric fingerprints of 12 or eight lipid sensors (for Chemlali and Sahli, respectively), selected using a simulated annealing meta-heuristic algorithm, allowed the correct prediction (repeated K-fold cross-validation) of the geographic production region with sensitivities of 92 ± 7% (Chemlali) and 97 ± 8% (Sahli). It was also confirmed the electronic tongue capability to classify Tunisian olive oil according to olive cultivar or quality grade. The results indicated the possible use of potentiometric fingerprints as a promising innovative strategy for olive oil analysis allowing assessing geographical origin, olive cultivar and quality grade, which are key factors determining olive oil price and consumers’ preference. 相似文献
894.
Influence of acceleration setting reaction by halogen light‐curing on GIC–dentin interface: Qualitative analysis by SEM
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Laysa Yoshioka Tamara Kerber Tedesco Ana Flávia Bissoto Calvo Sabrina Sun Ha Kim Anna Paula Vieira Ferreira Prado Malagrana Daniela Prócida Raggio 《Microscopy research and technique》2017,80(4):374-377
The aim of this study was to evaluate by scanning electron microscope (SEM) photomicrographs the influence of application of halogen light‐curing for fastening the set reaction of high‐viscosity glass ionomer cements (GIC) by assessing the material/dentin interface. Twelve human primary canines were assigned in four groups (n = 3) according to the GIC (Fuji IX, GC or Maxxion R, FGM) and application of halogen light‐curing (60 sec or control—no external energy). Blocks with approximately 6 mm of height were buildup on previously pre‐treated dentin surface in according to the experimental group. After storage at 37 °C, 100% humidity for 48 h, the specimens were then sectioned in slices with 1‐mm thick. The slices were qualitative analyzed using SEM to evaluate possible structural changes. Two examiners independently evaluated the images in order to observe the spherical hollow spaces of each tooth. The photomicrographs revealed the presence of spherical hollow spaces in all experimental groups. However, in both groups that received halogen light‐curing application, it was possible to observe that the presence of these hollow spaces decreased in size and quantity. It can be concluded that the halogen light‐curing application positively decreases in size and quantity in the presence of spherical hollow spaces in GIC. 相似文献
895.
Ana M. Girão Coelho Frans S.K. Bijlaard 《Journal of Constructional Steel Research》2007,63(9):1228-1240
The use of high strength steel in construction has recently provided some challenges to structural engineers. One such challenge is to minimise the cross-section dimensions as the material provides higher strength, which brings great economic benefits. However, high strength steels exhibit high yield ratios and limited deformation capacity when compared to mild steel grades. This behaviour can be particularly important when structures are designed for abnormal loading conditions that produce inelastic deformations. In this situation, both members and connections have to develop sufficient ductility. The connections between members, in particular, are the regions where the material is exposed to higher deformation demands. To address these topics, an experimental investigation was undertaken of moment connections with end-plates made up of the high strength steel S690. The major contributions of this study are (i) the characterisation of the nonlinear behaviour, (ii) the validation of current Eurocode 3 specifications and (iii) the ductility analysis of high strength steel moment connections. The test results show that the tested connections satisfy the current design provisions for stiffness and resistance and achieve reasonable rotation demands. 相似文献
896.
Ana Paula Koury 《Planning Perspectives》2020,35(4):657-687
ABSTRACT The social issue of housing has been a focal point in the criticism of Brazilian modernity, and it still plays a central role in the balance of Brazilian democracy. This paper discusses the investments in modern housing made by the welfare system in Brazil and which are related to the country's transition toward an urban society in the late 1930s. The analysis concludes in the 1960s, when these investments ended. The relationship between housing and the industrial economy characterized urban development in Brazil in this period. The latter saw direct state intervention in overseeing the building of houses for urban workers. This process started during Brazil's authoritarian regime [1937–1945], just as the cycle of Brazilian industrial democracy began in the mid-forties. The state housing policy worsened the urban crisis while also increasing the real estate market. It triggered several major controversies including an imbalance in urban classes associated with exclusively rich and poor neighbourhoods. The extension of the housing policy and social benefits to all citizens triggered tensions. These findings explain the challenges of political process, the changes in the housing policy and the swelling of Brazilian urban society. 相似文献
897.
Photodegradation study of three dipyrone metabolites in various water systems: identification and toxicity of their photodegradation products 总被引:1,自引:0,他引:1
The photochemical behaviour of three relevant metabolites of the analgesic and antipyretic drug dipyrone, 4-methylaminoantipyrine (4-MAA), 4-formylaminoantipyrine (4-FAA) and 4-acetylaminoantipyrine (4-AAA), was evaluated under simulated solar irradiation (Suntest system). For 4-MAA, different aqueous solutions (synthetic seawater, freshwater and Milli-Q water) as well as different operational conditions were compared. According to the experimental results, 4-MAA resulted as being an easily degraded molecule by direct photolysis, with half-life times (t1/2) ranging from 0.12 to 0.58 h, depending on the irradiation conditions. Faster degradation was observed in synthetic waters, suggesting that the photolysis was influenced by the salt composition of the waters. However, no effect on the degradation rate was observed by the presence of natural photosensitizers (dissolved organic matter, nitrate ions). 4-FAA and 4-AAA showed slower photodegradation kinetics, with t1/2 of 24 and 28 h, respectively. A study of photoproduct identification was carried out by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) (ESI positive mode), which allowed us to propose a tentative photodegradation pathway for 4-MAA and the identification of persistent by-products in all the cases. Finally, the application of an acute toxicity test (Daphnia magna) showed an increase in toxicity during the photolytic process, a consequence of the formation of toxic photoproducts. 相似文献
898.
899.
A preliminary planning methodology is presented. This approach relies upon a strategy identification mechanism, a system dynamics model to simulate the behaviour of the identified strategies and multiobjective programming formulations to evaluate them. An application to regional water resources planning in the Guadiana basin is included to illustrate the methodology. 相似文献
900.
M. Isabel Sarr Ana M. García Víctor M. Rivalta Diego A. Moreno Irene Arroyo 《Building and Environment》2006,41(12):1811-1820
Stone works of art exposed to the environment are liable to be deteriorated by the action of biological agents such as bacteria, fungi, mosses, etc. In ornamental fountains, the microorganisms present in water can contribute to these biodeterioration processes. This paper assesses the biodeterioration experienced by the Lions Fountain at the Alhambra Palace in Granada (Spain). Analyses have been made of the biodeterioration of Lions 4, 5 and 9, the biofouling of the fountain basin, and the water supply system. Conventional and molecular biology techniques have identified microorganisms belonging to various microbial groups (-, β- and γ-Protebacteria, Chlamydiae/Verrucomicrobia and Eukaryota). Additionally, on the mortar in the sculptures the presence of algae and bryophytes has been observed. X-ray diffraction allowed both the detection of neoformation mineral products that can be related with the presence of microorganisms and the corrosion products in the Lions Fountain. A number of recommendations are made regarding the prevention and control of biodeterioration in this important work of art. 相似文献