EDIC intensity correction of electron diffraction.

Transmission electron microscopy (TEM) has recently become indispensable in determining crystal structures. The location of atoms in crystals can be determined using electron diffraction (ED) intensity data series if the diffracted intensities are directly proportional to the square of the structure factor (|Fhkl|2). However, due to the crystal thickness, the used electron wavelength and the potential misalignment of the measured crystal the detected intensities differ from the ideal values. A method, Electron Diffraction Intensity Correction (EDIC), and a computer program have been developed to recover the ideal |Fhkl|2 proportional intensities from experimental data for kinematic scattering, for further structure studies.

Specimen preparation for nano-scale investigation of cementitious repair material.

Cementitious Repair Materials (CRMs) in the construction industry have been used for many decades now and has become a very important part of activities in cement world. The performance of some of these CRMs when applied to retrofitting concrete structural elements is also well documented. However, the characterization of some of the CRMs at the micro- and nano level is not fully documented. The first step to studying materials at the microscopic level is to be able to fabricate proper specimens for microscopy. In this study, a special and newly developed class of CRM was selected and fabricated by Focused Ion Beam (FIB) using well-known "Lift-out" technique. The prepared specimen was later examined using various analytical techniques such as energy dispersive x-ray analysis using one of the highest and most stable Scanning Transmission Electron Holography Microscopy (STEHM) around the world. This process enabled understanding of the composition, morphology, and spatial distribution of various phases of the CRM. It was observed that the microstructure consisted of a very fine, compact, and homogenous amorphous structure. X-ray analysis indicated that there was considerable deviation between the Si/Ca ratios for the hydrated product.

Transmission electron microscopy studies and modeling of 3D reciprocal space of ω forming alloy.

Initial stage of ω phase formation and associated anomalous features that appear in diffraction patterns of a metastable ß transition metal alloy have been investigated in this study with the aid of transmission electron microscopy, simulation and modeling. The paper explores discrete features that emerge in selected area diffraction patterns of quenched Ti-15wt%Mo alloy and analyzes the correlation between ω reflections and diffuse arcs by considering all variants of ω phase as per the formation kinetics of ω phase in ß matrix while quenching. Superimposed simulated diffraction patterns have been compared with experimental counterparts and it is deduced that there is lack of congruence between ω reflections and diffuse arcs even after considering trigonal ω with varying degrees of displacement. Direct lattice imaging of trigonal ω in ß matrix has been demonstrated by phase contrast microscopy coupled with Fourier filtering techniques. By investigating the nature of ω reflections and diffuse arcs with the aid of electron diffraction pattern calculations and phase contrast microscopy, it is shown that, existing model of three-dimensional (3D) reciprocal space of ω forming alloy at quenched stage is not complete. A new model incorporating a patterned intensity distribution is fitted at the octahedral sites of an fcc reciprocal lattice whose planar intersections with Ewald's sphere show a better fit with the observed experimental diffraction patterns.

Local, atomic-level elastic strain measurements of metallic glass thin films by electron diffraction.

A novel technique is used to measure the atomic-level elastic strain tensor of amorphous materials by tracking geometric changes of the first diffuse ring of selected area electron diffraction patterns (SAD). An automatic procedure, which includes locating the centre and fitting an ellipse to the diffuse ring with sub-pixel precision is developed for extracting the 2-dimensional strain tensor from the SAD patterns. Using this technique, atomic-level principal strains from micrometre-sized regions of freestanding amorphous Ti0.45Al0.55 thin films were measured during in-situ TEM tensile deformation. The thin films were deformed using MEMS based testing stages that allow simultaneous measurement of the macroscopic stress and strain. The calculated atomic-level principal strains show a linear dependence on the applied stress, and good correspondence with the measured macroscopic strains. The calculated Poisson's ratio of 0.23 is reasonable for brittle metallic glasses. The technique yields a strain accuracy of about 1×10(-4) and shows the potential to obtain localized strain profiles/maps of amorphous thin film samples.

Potential technique for tiny crystalline detection in lycopene-loaded SLN and NLC development.

CONTEXT: The advantage of solid nanocarriers like solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) is related to some degree of crystalline characteristics of the lipid. However, the detection of tiny content of crystalline structure in such nanoparticles is difficult. OBJECTIVE: The aim of this study was to explore a potential method for detection of low degree of crystalline characteristics of lycopene-loaded SLN and NLC. METHODS: Crystalline characteristics investigation was done by polarized light microscope (PLM), differential scanning calorimeter (DSC), X-ray diffractometer (XRD) and transmission electron microscope (TEM). RESULTS AND DISCUSSION: It was found that high crystalline characteristics as anisotropic molecular organization crystal of pure orange wax and lycopene could be investigated by PLM, DSC and WAXS. Low crystallinity of lycopene-loaded SLN and NLC could not be detected by those techniques. Electron diffraction mode of TEM showed potential detection of tiny crystalline characteristics of such systems. The diffraction pattern of lycopene-loaded SLN and NLC exhibited obvious zero order laue zone indicating an isotropic fine grained polycrystalline of the nanoparticles. CONCLUSION: It could be concluded that TEM is a promising method for detection of low-level crystallinity of solid nanocarriers.

Pt-Al2O3 interfaces in cofired ceramics for use in miniaturized neuroprosthetic implants.

A core element to miniaturized, hermetic encapsulations for neuroprosthetic implants with high numbers of stimulation channels is the creation of electrical feedthroughs. Platinum (Pt) and alumina (Al2 O3 ) are necessary to connect the sealed electronics to external components including electrode arrays that provide a neural interface function, as well as to sources of power or data. Combined with laser micro-processing, high-density feedthrough arrays were created with up to 2500 channels per cm(2) . The chemistry, micro structure, and crystallography of the Pt-Al2 O3 interface created by the cofiring of Pt particles and Al2 O3 particulate in binder were studied by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and selective area electron diffraction (SAED) to determine the nature of the Pt-Al2 O3 bond. While Pt-Al2 O3 interfaces only occurred in cases where the different grains were in distinct orientations where the crystal lattices matched, the addition of glass additives allowed for bonding nonmatching orientations by devitrification to form Pt-glass-Al2 O3 interfaces. The conditions for the formation of both mechanisms were determined, and it was shown that higher order crystal planes than previously described can be matched. Analyzing the lattice matches in detail showed the ability of the material compound to compensate for mismatches by the formation of dislocations, out-of-angle matching, lattice distortion, and the existence of semi-coherent interfaces in case of integer misfit ratios to create domain matching.

Enhanced antilipopolysaccharide (LPS) induced changes in macrophage functions by Rubia cordifolia (RC) embedded with Au nanoparticles.

In this paper, we have shown that gold nanoparticles (Au (NPs)) embedded in Rubia cordifolia (RC) matrix (RC-Au (NPs)) exhibit a high therapeutic value relating to its anti-inflammatory characteristics. It was prepared by utilizing the reducing properties of RC to convert HAuCl4 into Au (NPs). In order to compare its effectiveness, with respect to Au (NPs), the latter was synthesized separately by reducing HAuCl4 with lemon extract. These Au (NPs) along with RC-Au (NPs) were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and UV-visible spectroscopy. The enhancement in anti-inflammatory characteristics was assessed as its inhibitory potential for lipopolysaccharide (LPS)-induced nitric oxide (NO) release, by rat peritoneal macrophages. The RC-Au (NPs) significantly enhanced its potential to inhibit NO release, which was reported in terms of inhibitory concentration for 50% inhibition (IC50=11.98 ng/ml), as compared to either RC extract (IC50=47 × 10(3)ng/ml) or to Au (NPs) (IC50=587.50 ng/ml).

Multi-walled Сarbon Nanotubes Penetrate into Plant Cells and Affect the Growth of Onobrychis arenaria Seedlings.

Engineered nanoparticles (ENPs) are now being used in many sectors of industry; however, the impact of ENPs on the environment still requires further study, since their use, recycling, and accidental spill can result in the accumulation of nanoparticles in the atmosphere, soil, and water. Plants are an integral part of ecosystems; hence their interaction with ENPs is inevitable. It is important to understand the consequences of this interaction and assess its potential effects. The present research is focused on studying the effects of the industrial material Taunit, containing multi-walled carbon nanotubes (MWNTs), on plants, and testing of its ability to penetrate into plant cells and tissues. Taunit has been found to stimulate the growth of roots and stems and cause an increase in peroxidase activity inOnobrychis arenariaseedlings. Peroxidase activity increases with decreasing concentration of Taunit from 1,000 to 100 mg/l. MWNTs from Taunit were detected in the cells and tissues of seedling roots and leaves, implying the ability of MWNTs to penetrate into roots and accumulate there, as well as their ability to be transported into seedling leaves. Thus, the changes in the physiological parameters of plants are associated not only with MWNT adsorption on the root surface, as previously believed, but also with their penetration, uptake and accumulation in the plant cells and tissues.