Laser-Empowered Random Metasurfaces for White Light Printed Image Multiplexing

Printed image multiplexing based on the design of metasurfaces has attracted much interest in the past decade. Optical switching between different images displayed directly on the metasurface is performed by altering the parameters of the incident light such as polarization, wavelength, or incidence angle. When using white light, only two-image multiplexing is implemented with polarization switching. Such metasurfaces are made of nanostructures perfectly controlled individually, which provide high-resolution pixels but small images and involve long fabrication processes. Here, it is demonstrated that laser processing of nanocomposites offers a versatile low-cost, high-speed method with large area processing capabilities for controlling the statistical properties of random metasurfaces, allowing up to three-image multiplexing under white light illumination. By independently controlling absorption and interference effects, colors in reflection and transmission can be varied independently yielding two-image multiplexing under white light. Using anisotropy of plasmonic nanoparticles, a third image can be multiplexed and revealed through polarization changes. The design strategy, the fundamental properties, and the versatility of implementation of these laser-empowered random metasurfaces are discussed. The technique, applied on flexible substrate, can find applications in information encryption or functional switchable optical devices, and offers many advantages for visual security and anticounterfeiting.     

A multi-sequences MRI deep framework study applied to glioma classfication

Multimedia Tools and Applications - Glioma is one of the most important central nervous system tumors, ranked 15th in the most common cancer for men and women. Magnetic Resonance Imaging (MRI)...     

Nanoscale Phase Separation in Lithium Niobium Silicate Glass by Femtosecond Laser Irradiation

Understanding the phase transformation in glass and the morphology of related nanostructure after femtosecond laser irradiation is of great importance for fabricating functional optics, in which glass crystallization is involved to obtain nonlinear optical properties. We report on the crystallization inside lithium niobium silicate glass induced by fs laser irradiation. Energy‐dispersive X‐ray spectroscopy coupled to scanning transmission electron microscopy (STEM/EDS) and transmission electron microscopy confirm a nanoscale phase separation whereby LiNbO₃ crystals are embedded in lamella‐shaped frames of amorphous SiO₂. The obtained nanostructure may have applications in fabricating second‐order nonlinear optical devices.     

Magneto‐Thermal Metrics Can Mirror the Long‐Term Intracellular Fate of Magneto‐Plasmonic Nanohybrids and Reveal the Remarkable Shielding Effect of Gold

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).     

STEP-NC compliant process planning of additive manufacturing: remanufacturing

Additive manufacturing is becoming one of the key methods for reproducing repair sections in remanufacturing processes. The major advantage of using additive processes is to minimize production time and waste. However, the surface quality and shape accuracy are usually insufficient for the final product because the approximated representation format causes the accumulation of the error during the geometric operations of the process planning. This limitation is a barrier to utilize additive processes as finishing processes, such as general metal cutting. There is need to improve the final quality of parts obtained with additive manufacturing. In this paper, STEP-based numerical control (STEP-NC)-based process planning is applied to the additive manufacturing. ISO 14649 (STEP-NC) describes part programs with geometric data directly and also contains the information necessary for the intelligent process planning. This paper proposes the STEP-NC-based representation method of additive manufacturing and the series of geometric reasoning to automate the derivation of the repair section. The proposed representation has the benefits to provide a high accuracy for the final surface and to describe multiple materials. Topological data maintain low error during the series of process planning through the CAD-CAM-CNC chain. The proposed platform supports consideration of the process tolerance and comparison of the selected plan with alternative processes. In order to show the practical advantages, an analysis of the remanufacturing process is carried out. The case study of remanufacturing a pocket part is presented in order to validate the proposed process plan. The result of the case study shows the improvement in terms of automatic process planning and surface quality accuracy.     

Same Neighbourhood … Different Views? A Confrontation of Internal and External Neighbourhood Reputations

Residents and non-residents are likely to think differently about a neighbourhood's reputation. Relatively little is known about the similarities and differences between these internal and external types of neighbourhood reputation or the relationship between reputations and ‘real’ or ‘objective’ neighbourhood characteristics. This paper addresses two points: first, the extent to which neighbourhood reputations differ between and within groups; second, the extent to which these neighbourhood reputations are associated with measured neighbourhood characteristics. Data from a specially designed survey carried out in 24 neighbourhoods in Utrecht, the fourth largest city in the Netherlands, are used. Analysis of the data showed that neighbourhood reputations are rated higher by residents and estate agents than by other city residents. Within the group of other city residents, differences were found in how neighbourhood reputations are rated by socio-economic status, ethnicity and educational background. Further, it was found that neighbourhood reputations are correlated with measured social characteristics of the neighbourhood, while physical and functional neighbourhood characteristics are of less importance.     

Microstructural investigation of magnetic CoFe2O4 nanowires inside carbon nanotubes by electron tomography

Magnetic nanowires of CoFe 2O4 were casted inside the channel of multiwall carbon nanotubes by mild chemical synthesis. A detailed investigation of these nanowires was performed using mainly the electron tomography technique; this study provides a complete characterization of their microstructure in terms of the spatial organization and the size distribution of individual particles forming the nanowire as well as its residual porosity. In particular, we have shown that the size of the CoFe 2O4 monocrystalline particles is closely dependent on the location of the particle within the nanotube, i.e., small particles close to the tube tip (5 nm) and bigger particles inside the tube channel (15 nm). As the theoretical critical size for superparamagnetic relaxation in CoFe 2O4 is estimated within the range of 4-9 nm, the size distribution obtained by 3D-TEM agrees with the Mossbauer study that suggests the presence of two different magnetic components inside the nanowire. We have shown also that, by using this preparation method and for this internal diameter of nanotube, the CoFe 2O4 nanowire exhibits a continuous structure along the tube, has a residual porosity of 38%, and can fill the tube at only 50%, parameters which influence in a significant manner the magnetic behavior of this system.     

Moisture balance assessment at room scale for four cases based on numerical simulations of heat–air–moisture transfers for a realistic occupancy scenario

The moisture balance at room scale is influenced by the air change rate, moisture production and vapour transfer with the envelope. However, results may differ strongly from one study to another depending on the sizing of the ventilation system, the boundary conditions and the modelling of vapour transfer in the walls. This paper aims to provide a realistic comparison of usual construction techniques based on energy consumption, indoor comfort and durability. To achieve this objective, an existing whole-building heat–air–moisture simulation tool was selected to compute coupled transfer at room scale over an entire year. Moisture production due to occupancy was modelled using a stochastic approach. Four cases were selected to emphasize the differences of both a vapour-permeable wall assembly and a relative humidity sensitive ventilation system compared to common practices.     

3D electron microscopy study of metal particles inside multiwalled carbon nanotubes

The location of palladium nanoparticles on and inside the multiwalled carbon nanotubes channel is presented for the first time using electron tomography (3D TEM). The palladium salt precursor was rapidly sucked inside the nanotube channel by means of capillarity that is favored by the hydrophilic character of the tube wall after acidic treatment at low temperature. Statistical analysis indicates that the palladium particles were well dispersed and the palladium particle size was relatively homogeneous, ranging from 3 to 4 nm regardless of their location within the nanotube, within the resolution limit of the technique for our experimental conditions, i.e., about 2 nm. Three-dimensional TEM analysis also revealed that introduction of foreign elements inside the tube channel is strongly influenced by the diameter of the tube inner channel, i.e., easy filling seems to occur with a tube channel >or=30 nm , whereas with tubes having a smaller channel (<15 nm), almost no filling by capillarity occurred leading to the deposition of the metal particles only on the outer wall of the tube.     

Inhibition of Very Long Chain Fatty Acids Synthesis Mediates PI3P Homeostasis at Endosomal Compartments

A main characteristic of sphingolipids is the presence of a very long chain fatty acid (VLCFA) whose function in cellular processes is not yet fully understood. VLCFAs of sphingolipids are involved in the intracellular traffic to the vacuole and the maturation of early endosomes into late endosomes is one of the major pathways for vacuolar traffic. Additionally, the anionic phospholipid phosphatidylinositol-3-phosphate (PtdIns (3)P or PI3P) is involved in protein sorting and recruitment of small GTPase effectors at late endosomes/multivesicular bodies (MVBs) during vacuolar trafficking. In contrast to animal cells, PI3P mainly localizes to late endosomes in plant cells and to a minor extent to a discrete sub-domain of the plant’s early endosome (EE)/trans-Golgi network (TGN) where the endosomal maturation occurs. However, the mechanisms that control the relative levels of PI3P between TGN and MVBs are unknown. Using metazachlor, an inhibitor of VLCFA synthesis, we found that VLCFAs are involved in the TGN/MVB distribution of PI3P. This effect is independent from either synthesis of PI3P by PI3-kinase or degradation of PI(3,5)P₂ into PI3P by the SUPPRESSOR OF ACTIN1 (SAC1) phosphatase. Using high-resolution live cell imaging microscopy, we detected transient associations between TGNs and MVBs but VLCFAs are not involved in those interactions. Nonetheless, our results suggest that PI3P might be transferable from TGN to MVBs and that VLCFAs act in this process.