Quantitative 3D Real-Space Analysis of Photonic Supraparticles.

Correlation microscopy combining fluorescence and scanning probe or electron microscopy is limited to fixed samples due to the sample preparation and nonphysiological imaging conditions required by most probe or electron microscopy techniques. Among the few scanning probe techniques that allow imaging of living cells under physiological conditions, scanning ion conductance microscopy (SICM) has been shown to be the technique that minimizes the impact on the investigated sample. However, combinations of SICM and fluorescence microscopy suffered from the mismatch in resolution due to the limited resolution of conventional light microscopy. In the last years, the diffraction limit of light microscopy has been circumvented by various techniques, one of which is stimulated emission depletion (STED) microscopy. Here, we aimed at demonstrating the combination of STED and SICM. We show that both methods allow recording a living cellular specimen and provide a SICM and STED image of the same sample, which allowed us to correlate the membrane surface topography and the distribution of the cytoskeletal protein actin. Our proof-of-concept study exemplifies the benefit of correlating SICM with a subdiffraction fluorescence method and might form the basis for the development of a combined instrument that would allow the simultaneous recording of subdiffraction fluorescence and topography information.

Colloids, polymers, gels, and biological materials are widely used for numerous technological applications. The design, fabrication, and understanding of the physico-chemical properties of such (bio)materials, however, represent a challenge for scientists and technologists. This review is a concise update of the latest achievements in surface and bulk analytical techniques applied to biomaterials and soft matter systems. Specific emphasis is devoted to their structural, mechanical, surface, and chemical properties. The review introduces the basics of atomic force microscopy (AFM) and discusses its combination with optical microscopies and spectroscopic techniques. In particular, we report the AFM combination with fluorescence, confocal microscopy, stimulated emission depletion, Raman, and infrared spectroscopy. The review highlights the impact and the potential applications of the combination of such experimental techniques on current problems and questions related to material and polymer science, cell biology, biochemical engineering, and protein chemistry. This review is an accessible introduction to AFM for the newcomer and a source of new experimental information for the experienced researcher.

Hierarchical structured SiO2@γ-AlOOH spheres were fabricated in one step by using silica colloidal spheres as atemplate. Scanning electron microscopy and transmission electron microscopyinvestigation showed that the shell is composed of large amounts of nanoscaleγ-AlOOHlamellas. The growth mechanism was proposed as silica template-induced heterogeneous depositionof γ-AlOOH lamellas. The adsorption properties of hierarchicalSiO2@γ-AlOOH spheres annealed at different temperatures were investigated through the removaltest of Cr(VI) ions in model wastewater, and the nanostructures annealed at400 °C showed good adsorption capability of Cr(VI) ions.

By allowing insured communication between cancer cells themselves and with the neighboring stromal cells, tunneling nanotubes (TNTs) are involved in the multistep process of cancer development from tumorigenesis to the treatment resistance. However, despite their critical role in the biology of cancer, the study of the TNTs has been announced challenging due to not only the absence of a specific biomarker but also the fragile and transitory nature of their structure and the fact that they are hovering freely above the substratum. Here, we proposed to review guidelines to follow for studying the structure and functionality of TNTs in tumoral neuroendocrine cells (PC12) and nontumorigenic human bronchial epithelial cells (HBEC-3, H28). In particular, we reported how crucial is it (i) to consider the culture conditions (culture surface, cell density), (ii) to visualize the formation of TNTs in living cells (mechanisms of formation, 3D representation), and (iii) to identify the cytoskeleton components and the associated elements (categories, origin, tip, and formation/transport) in the TNTs. We also focused on the input of high-resolution cell imaging approaches including Stimulated Emission Depletion (STED) nanoscopy, Transmitted and Scanning Electron Microscopies (TEM and SEM). In addition, we underlined the important role of the organelles in the mechanisms of TNT formation and transfer between the cancer cells. Finally, new biological models for the identification of the TNTs between cancer cells and stromal cells (liquid air interface, ex vivo, in vivo) and the clinical considerations will also be discussed.

Behind-armor Fragments from Tungsten Rods Penetrating Steel

Magic numbers in finite particle systems correspond to specific system sizes that allow configurations with low free energy, often exhibiting closed surface shells to maximize the number of nearest neighbors. Since their discovery in atomic nuclei, magic numbers have been essential for understanding the number-structure-property relationships in finite clusters across different scales. However, as the system size increases, the significance of magic numbers diminishes, and the precise system size at which magic number phenomena disappear remains uncertain. In this study, we investigate colloidal clusters formed through confined self-assembly. Small magic number clusters display icosahedral symmetry with closed surface shells, corresponding to pronounced free energy minima. Our findings reveal that beyond a critical system size, closed surface shells disappear, and free energy minima become less pronounced. Instead, we observe a distinct type of colloidal cluster, termed a football cluster, which retains icosahedral symmetry but features lower-coordinated facets disconnected by terraces. A sphere packing model demonstrates that forming closed surface shells becomes impossible beyond a critical system size, explaining the breakdown of magic numbers in large confined systems.

Auto-SEM particle shape characterisation: Investigating fine grinding of UG2 ore

A new Al-Pd-Mn phase, called F2M, and its reversible transformation with an icosahedral structure at high temperature have been identified in a previous synchrotron X-ray diffraction study (de Boissieu et al. 1998, Phil. Mag. A, 78, 305). From the present results of a transmission electron microscopy study, it is shown that such a phase exhibits a cubic symmetry with local cubic approximant arrangements of huge cell parameter (a = 294 ± 1.5 A). The microstructure of the F2M phase is multidomains with crystallographic orientational relationships between domains imparting an overall icosahedral symmetry. An interpretation in terms of a superlattice ordering of cubic symmetry in a super-ordered icosahedral phase (i.e. the F2 phase described by Ishimasa (1995, Phil. Mag. Lett., 71, 65) is proposed on the basis of an analysis of the peculiar sandwich structure observed along (111) threefold axes of the F2M structure. A crystallographic space group for local cubic arrangements is also proposed.

We show an effective experimental method to prepare hierarchically porous zinc oxide (ZnO) spherical nanoparticles through a self-assembly pathway using surface-modified colloidal ZnO nanocrystallites as the building blocks and P-123 copolymers as the template in aqueous solution. Copolymers are thoroughly removed by Soxhlet extraction with ethanol and calcination at 400 °C. The final products have been characterized by X-ray powder diffraction (XRD) pattern, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and photoluminescence (PL) spectroscopy. On the basis of calorimetric measurements reported separately, the surface enthalpy (γ) of the hydrated porous ZnO is 1.42 ± 0.21 J/m2, in good agreement with that of ZnO nanoparticles. The calorimetric results support the presence of self-assembled ZnO nanocrystallites in the nanoporous ZnO. Photocatalytic activitiy of porous ZnO nanoparticles has been tested on the photodegradation of phenol under ambient condition, indicating that porous ZnO nanoparticles show superior activity to TiO2 nanoparticles (PC-500).

In this paper we present the preliminary results of morphological analysis of Fe59Mn36.5Al3.10C3.56Cu0.237%Wt alloy. This alloy was prepared by mechanical alloying with various milling times, then hot compacted at various pressures and finally underwent presented a sintering process. The samples were characterized structurally by experimental techniques such as: X-ray diffraction and scanning electron microscopy. Each micrograph was analysed by fractal dimension using the Box Counting method in 2D; this type of tool allows you to assign a numerical value to the region which has been applied the technic. This numerical value is associated with the properties obtained by experimental techniques such as microhardness.

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

Impact of Li-ions and CO2 on the electrochemical efficiency of Al and Al-4%Sn in KOH electrolyte for alkaline batteries application

Experimental techniques have been developed to evaluate performance of nanoemulsions as pre-pad fluid for reducing water-cut in tight gas formations with multistage hydraulic fractures. More specifically, an aminopolysiloxane nanoemulsion was prepared and formulated in the laboratory for effective and efficient water control. The water-control mechanisms of nanoemulsions as pre-pad fluid in hydraulic fracturing were identified by performing the scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), spontaneous imbibition tests, and wettability measurements. The SEM and XPS tests confirm that certain changes occur in the element compositions and microstructure of the core surface before and after introducing the prepared nanoemulsions on the reservoir rock surface. Such changes irreversibly alter its wettability, indicated by the measured contact angle from 75° to 128°. During the displacement experiments, there exists a disproportionate permeability reduction on relative permeability ...

Photocatalytic decomposition of pollen allergenic extracts of Cupressus arizonica and Platanus hybrida

The structure of finite self-assembling systems depends sensitively on the number of constituent building blocks. Recently, it was demonstrated that hard sphere-like colloidal particles show a magic number effect when confined in emulsion droplets. Geometric construction rules permit a few dozen magic numbers that correspond to a discrete series of completely filled concentric icosahedral shells. Here, we investigate the free energy landscape of these colloidal clusters as a function of the number of their constituent building blocks for system sizes up to several thousand particles. We find that minima in the free energy landscape, arising from the presence of filled, concentric shells, are significantly broadened, compared to their atomic analogues. Colloidal clusters in spherical confinement can flexibly accommodate excess particles by ordering icosahedrally in the cluster center while changing the structure near the cluster surface. In between these magic number regions, the building blocks cannot arrange into filled shells. Instead, we observe that defects accumulate in a single wedge and therefore only affect a few tetrahedral grains of the cluster. We predict the existence of this wedge by simulation and confirm its presence in experiment using electron tomography. The introduction of the wedge minimizes the free energy penalty by confining defects to small regions within the cluster. In addition, the remaining ordered tetrahedral grains can relax internal strain by breaking icosahedral symmetry. Our findings demonstrate how multiple defect mechanisms collude to form the complex free energy landscape of colloidal clusters.