The nanoscale manipulation and charge transport properties of the Fe(Htrz)2(trz)(BF4) spin‐crossover compound is demonstrated. Such 1D spin‐crossover nanostructures are attractive building blocks for ...nanoelectronic switching and memory devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Nanotherapy using targeted magnetic nanoparticles grafted with peptidic ligands of receptors overexpressed in cancers is a promising therapeutic strategy. However, nanoconjugation of peptides can ...dramatically affect their properties with respect to receptor recognition, mechanism of internalization, intracellular trafficking, and fate. Furthermore, investigations are needed to better understand the mechanism whereby application of an alternating magnetic field to cells containing targeted nanoparticles induces cell death. Here, we designed a nanoplatform (termed MG-IONP-DY647) composed of an iron oxide nanocrystal decorated with a ligand of a G-protein coupled receptor, the cholecystokinin-2 receptor (CCK2R) that is overexpressed in several malignant cancers. MG-IONP-DY647 did not stimulate inflammasome of Raw 264.7 macrophages. They recognized cells expressing CCK2R with a high specificity, subsequently internalized via a mechanism involving recruitment of β-arrestins, clathrin-coated pits, and dynamin and were directed to lysosomes. Binding and internalization of MG-IONP-DY647 were dependent on the density of the ligand at the nanoparticle surface and were slowed down relative to free ligand. Trafficking of CCK2R internalized with the nanoparticles was slightly modified relative to CCK2R internalized in response to free ligand. Application of an alternating magnetic field to cells containing MG-IONP-DY647 induced apoptosis and cell death through a lysosomal death pathway, demonstrating that cell death is triggered even though nanoparticles of low thermal power are internalized in minute amounts by the cells. Together with pioneer findings using iron oxide nanoparticles targeting tumoral cells expressing epidermal growth factor receptor, these data represent a solid basis for future studies aiming at establishing the proof-of-concept of nanotherapy of cancers using ligand-grafted magnetic nanoparticles specifically internalized via cell surface receptors.
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IJS, KILJ, NUK, PNG, UL, UM
We report for the first time the unidirectional spin state switching of a spin crossover compound at micrometric scale using an electric field.We study the stability and lifetime of the electric ...field induced state.We use a model based on the interaction between the electric field and the electric dipolar momentum of spin crossover complex in order to explain our experimental data.
We report on a molecular spin-state switching phenomenon induced by an electric field in micrometric objects of the Fe(Htrz)2(trz)(BF4) spin crossover complex, organized between interdigitated electrodes. By applying an electric field step of 40kV/cm at temperatures within the thermal hysteresis region of the first-order spin transition, the iron(II) ions are switched from the metastable high spin to the stable low spin state obtaining a rather incomplete transition but perfectly reversible by heating. A model based on the interaction between the electric field and the electric dipolar moment of spin crossover complexes, grasps the main features of the experimental data.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
South-East Asia is well-known for traditionally fermented foods. However, these products are generally still produced at small scale following traditional procedures. Nowadays, consumers are ...particularly aware of the health concerns regarding food additives; the health benefits of “natural” and “traditional” foods, processed with no added chemical preservatives, are becoming more and more attractive. Therefore, their confidence towards safety and quality of Asian fermented foods is low. Major food safety concerns are related not only to food production methods, but also to how foods are processed, stored, sold and consumed. In this review the main factors affecting food safety are analysed. They are not limited only to the improper use of chemicals such as pesticides or antibiotics, but also to improper processing and handling during storage which could provoke the accumulation of toxic compounds such as mycotoxins or biogenic amines. Urgent attention is required to improve the quality of the ingredients and the integration of food safety management systems for industrial growth. Therefore, in the last part of this review directions to improve the food safety of fermented foods are proposed.
•Several safety risks concern South-East Asia fermented food.•Bad agriculture practices are responsible for many contaminations.•The use of a selected flora could decrease many problems.•Many actors of the production chain seem unaware of the risks.•Some products exhibit a high safety quality showing that solutions exist.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We studied the effect of light irradiation on the electrical conductance of micro-rods of the spin crossover Fe(Htrz)2(trz)(BF4) network, organized between interdigitated gold electrodes. By ...irradiating the sample with different wavelengths (between 295 and 655 nm) either in air or under a nitrogen atmosphere we observed both a reversible and an irreversible change of the current flowing in the device. The reversible process consists of an abrupt decrease of the current intensity (ca. 10-50%) upon light irradiation, while the irreversible process is characterized by a slow, but continuous increase in time of the current, which persists also in the dark. These photo-induced processes were only detected in the high conductance low-spin (LS) state of the complex. On switching the rods to the high spin (HS) state the conductance decreases two orders of magnitude (at the same temperature) and - as a consequence - the photo-effect vanishes.
Tonle Sap Lake, the largest freshwater body in Southeast Asia, plays an important role in lives and environment. The lake is reportedly under anthropogenic pressure and suffers from eutrophication. ...The floating villagers suffer from waterborne diseases. However, the shift in bacterial community due to human activities in this great lake has not yet been reported. We aimed to determine the dynamics of the bacterial community and their concentration in the lake using 67 surface waters, 53 sub-layer waters and 59 sediment samples by Next Generation Sequencing (NGS). The bacterial communities in the surface water and sub-layer water were similar but they differed from the sediment; however, their abundance showed spatiotemporal variations. The bacterial diversity reached the highest value in the dry season but lowest value in the rainy season in the surface water and sediment. Their diversity in the sub-layer water was highest in the transition from dry to rainy season. The total 16S rRNA gene copy number in the sediment were >100 times higher than that measured in the water. The Cyanobacteria, Actinobacteria, and Proteobacteria concentrations in the lake water increased in the dry season and reached a peak in the transition from dry to rainy season. The concentrations of Proteobacteria and Firmicutes elevated in the lake water and sediment, respectively, in the floating villages which were >10 times higher than the places with non-point sources. The bacterial concentration and its diversity in the Tonle Sap Lake changed based on the lake water volume between rainy and dry season. The bacterial concentration in the Tonle Sap Lake diluted with the water inflow from Mekong River and its tributaries in the rainy season. As influenced by the fecal waste, the bacterial community in the floating villages differed from the places with non-point source.
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•The Tonle Sap Lake bacterial community differed between the water and sediment.•The bacterial community abundance varied with location and season.•Bacterial diversity in the deep-water increased during the transition season.•The bacterial concentration condensed in the lake water during low-water periods.•The floating villages' bacterial community differed from that at non-point sources.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► Investigate the effect of heat-alkaline treatment on volatile fatty acid production and protein degradation. ► Quantify bacteria present in the activated sludge by quantitative PCR. ► HAT enhances ...VFA production only in excess sludge, albumin, and Gram-negative bacteria. ► Gram-negative bacteria are predominant in the activated sludge used. ► Bacteria present in activated sludge comprise only 10% of mixed liquor suspended solids by qPCR.
This study investigated the effect of heat-alkaline treatment (HAT) at pH 11 and 60°C on volatile fatty acid (VFA) production and protein degradation in excess sludge, soluble and insoluble proteins, and pure cultures. In addition, quantification of bacteria present in the sludge was also examined. Experimental results showed that following acid fermentation under pH 7 and 37°C, HAT enhanced VFA production in excess sludge, albumin, and Gram-negative bacteria, but not in casein or Gram-positive bacteria. Protein solubility was therefore found not to be the main criteria for VFA production. In the protein analysis, it was shown that the outer membrane protein (OmpC) of Escherichia coli K12 was resistant to chemical and enzymatic hydrolysis. Gram staining revealed that Gram-negative bacteria were predominant in the activated sludge used in this study. In addition, the bacteria present in the activated sludge comprised only 10% of mixed liquor suspended solids (MLSS) by quantitative PCR.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report a chemical method to prepare metallic Fe porous nanocubes. The presence of pores embedded inside the cubes was attested by electron tomography. Thanks to electronic holography and ...micromagnetic simulations, we show that the presence of these defects stabilizes the vortices in assembly of interacting cubes. These results open new perspectives toward magnetic vortex stabilization at relatively low cost for various applications (microelectronics, magnetic recording, or biological applications).
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In this article we investigated the stability of the particles before their integration in a microelectronic device, and revealed a remarkable robustness of the spin crossover even after performing ...3000 switching cycles. The stability of the device after more than 20 cycles was also studied. Display omitted
In this paper we report on the integration of micro-rods of the Fe(Htrz)2(trz)(BF4) spin crossover compound into an electronic switch-type device. The device has been fabricated by organizing the micrometric particles between interdigitated gold electrodes using dielectrophoresis and the influence of dielectrophoresis parameters on their integration is also examined. A particular attention was devoted to the investigation of the stability of the spin transition and the associated device properties. The stability of the particles before dielectrophoresis was investigated using variable temperature diffuse reflectivity experiments, which revealed a remarkable stability of the spin crossover even after performing 3000 switching cycles. We show also that the spin transition is not influenced by the solvents used for device fabrication, neither by the atmosphere (ambient air or vacuum) in which the device is used. The spin transition remains reproducible over several tens of cycles even at the device level, but the current in the device decreases continuously.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Cobalt nanorods possess ideal magnetic properties for applications requiring magnetically hard nanoparticles. However, their exploitation is undermined by their sensitivity toward oxygen and water, ...which deteriorates their magnetic properties. The development of a continuous metal shell inert to oxidation could render them stable, opening perspectives not only for already identified applications but also for uses in which contact with air and/or aqueous media is inevitable. However, the direct growth of a conformal noble metal shell on magnetic metals is a challenge. Here, we show that prior treatment of Co nanorods with a tin coordination compound is the crucial step that enables the subsequent growth of a continuous noble metal shell on their surface, rendering them air- and water-resistant, while conserving the monocrystallity, metallicity and the magnetic properties of the Co core. Thus, the as-synthesized core–shell ferromagnetic nanorods combine high magnetization and strong uniaxial magnetic anisotropy, even after exposure to air and water, and hold promise for successful implementation in in vitro biodiagnostics requiring probes of high magnetization and anisotropic shape.
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