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To replicate a venous blood gas composition during Ex-Situ Lung Perfusion (ESLP), a membrane deoxygenator is employed, across which a mixed (N 2 /O 2 /CO 2) or pure sweep gas (CO 2) is applied to target a physiologic perfusate pCO 2 and pH. Clinically, mild permissive alkalosis counteracts elevated pulmonary vascular resistance (PVR) through vasodilation. We have previously observed an initial increase in PVR and pulmonary artery pressure (PAP) during porcine ESLP that mirrors a rise in pro-inflammatory cytokines. Increased hydrostatic pressure can worsen edema and lung compliance. We hypothesized that mild permissive alkalosis may improve outcomes in ESLP. Twelve sets of juvenile pig lungs (50 kg) underwent 12-hours of Negative Pressure Ventilation (NPV)-ESLP targeting a physiologic pH (Control: pH 7.35-7.45, n=6) or mild permissive alkalosis (pH+: pH 7.45-7.55, n=6) through varying the delivery of CO 2. At evaluation, lung oxygenation was assessed with a mixed sweep gas to deoxygenate the perfusate. Three left lungs from each group were transplanted and assessed over 4-hours. Results are reported pH+ vs Control. Both groups had acceptable oxygenation (PaO 2 /FiO 2 454.2 vs 438.2; p=0.37) and dynamic compliance (21.38 vs 22.22 ml/cmH 2 O; p=0.41) over 12-hour NPV-ESLP. Mean evaluation pH/pCO 2 /HCO 3 − were 7.50/15.6/14.5 vs 7.41/38.7/24.7. Mean PAP was similar (10.89 vs 14.12; p= 0.19) as was PVR (438.60 vs 557.9; p=0.21). The Control group required THAM and nitroglycerin boluses on ESLP to control acidosis and elevated PVR; this was not necessary in the pH+ group. Weight-gain/hour was similar (1.23% vs 1.38%; p=0.37). Mean left lung PF ratios 4-hours post-transplantation were 301 mmHg vs 196 mmHg (p= 0.11). Control TNF-⍺ perfusate concentrations were significantly greater at 1 (p = 0.02) and 3 (p=0.04) hours of ESLP. Five Control lungs failed on ESLP (T5-T8) due to high PAPs, low compliance, and poor oxygenation. Mild permissive alkalosis porcine NPV-ESLP demonstrated more reliable preservation and superior transplantation outcomes compared to a physiologic pH strategy. These findings suggest that mild alkalosis may protect highly reactive pig vasculature through vasodilation, thereby increasing the reliability of preservation. Optimization of pre-clinical protocols in large animals is required to improve human applications. [ABSTRACT FROM AUTHOR]

The dissolution and growth of Al 3 (Er, Zr) precipitates during tensile fatigue experiments were investigated by quasi-in situ and post-mortem scanning transmission electron microscopy with Z contrast imaging and X-ray energy dispersive spectroscopy. Al 3 (Er, Zr) particles were observed with both non-core–shell and core–shell structures, which were formed during multiple-stage precipitations, in an Al–Mg–Er alloy. After fatigue deformations, the average size of the non-core–shell structured precipitates increased significantly. By tracing the same precipitate particles before and after a high-cycle fatigue test, quasi-in situ electron microscopy revealed that the increase of average particle size is associated with the substantial dissolution of small non-core–shell structured Al 3 (Er, Zr) particles, whose diameters are generally less than 15 nm, and a consequent growth of larger non-core–shell Al 3 (Er, Zr) precipitates. On the contrary, the core–shell structured Al 3 (Er, Zr) precipitates remain stable during high-cycle fatigue tests. Possible mechanisms for the dissolution and growth of non-core–shell structured Al 3 (Er, Zr) precipitates are discussed in terms of particle size, interfacial energy and lattice mismatch, in comparison to the stable core–shell structured precipitates. [ABSTRACT FROM AUTHOR]

Abstract: Using in situ transmission electron microscopy and electron tomography, we have studied the healing process of submicron-scale voids embedded in a cold-rolled Al–Mg–Er alloy. The results show that voids are healed successfully within 50min at a relatively low temperature of 453K. Quantitative analysis of the in situ micrographs reveals that the void-healing process involves several stages: an initial fast-healing stage, then a slow-healing stage, and finally a rapid healing near the end. The different healing rates are likely related to varying surface curvatures due to the evolution of void geometry during the healing process. Because the voids are embedded inside Al alloy grains, lattice diffusion is considered to dominate the entire healing process. Mg enrichment was observed at the healed voids immediately after the healing. This indicates that the faster diffusion of Mg atoms in the Al matrix enhances void healing in the Al–Mg–Er alloy. Post-mortem experiments verify that voids in bulk cold-rolled Al–Mg–Er alloy can also be healed by 1h of annealing at 473K, consistent with the in situ experiments. The fatigue crack growth resistance and plasticity of the cold-rolled Al alloy are improved significantly after annealing at 473K. [Copyright &y& Elsevier]

Macroscopically zero-strained twin lamellae are observed in a coarse-grained Ni–Co-based superalloy after plastic deformation. The twin lamellae presented as three layers of overlapping stacking faults with zero overall Burgers vector. The atomic stacking sequence in the twin lamellae is consistent with pairs of parallel stacking faults at neighboring or next-neighboring glide planes. The twinning is facilitated by the low stacking fault energy of the superalloy and the lengthening of stacking faults by shear stress from nearby stacking faults. [ABSTRACT FROM AUTHOR]

Abstract: In order to faithfully investigate the microscopic and mesoscopic structures of bulk metallic glass (BMG) materials, inhomogeneous contrast in nanometer to micrometer scale in BMG specimens has been throughoutly studied by transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). It is found that ion-milling induced surface roughening and pattern formation are the source of the inhomogeneous contrast in TEM images of BMG samples. Additionally, high resolution TEM and X-ray energy dispersive spectroscopy investigations rule out structure or composition changes in the specimens. The dynamic roughening process during ion-milling as well as saturated pattern sizes are revealed from Zr-, Cu-, Fe- and Mg-based BMGs. The understanding of this inhomogeneous etching in BMG specimens is critical for recently intensive TEM studies on microscopic and mesoscopic inhomogeneities of BMGs. [Copyright &y& Elsevier]

Abstract: Variable resolution fluctuation electron microscopy (FEM) experiments are implemented with hollow-cone dark-field transmission electron microscopy. Medium range order lengths of zirconium and iron based bulk metallic glasses and amorphous silicon nitride are determined from the FEM results. It shows that maximum normalized intensity variances of FEM images occur when their nominal resolution approaches the correlation length Λ of the amorphous materials. Additionally, differences in the length and magnitude of medium range order are compared between metallic and covalent bond amorphous materials. [Copyright &y& Elsevier]

Abstract: A martensitic transformation from the α to the γ phase of aluminum oxide was observed by transmission electron microscopy (TEM) upon rapid heating induced by pulsed laser irradiation. Two variants possessing a twin relationship were found in the product. High-resolution TEM reveals that the transformation is achieved via the glide of quarter partial dislocations on every other basal plane of α-Al2O3. The high thermal stress caused by pulsed laser irradiation is believed to be the main driving force of the phase transformation. This martensitic transformation is associated with a positive volume change and substantial shear strain. The overall shear strain could be minimized by the self-accommodating variants. These characteristics suggest potential application of the martensitic transformation for transformation toughening in ceramic materials. [Copyright &y& Elsevier]

Abstract: We study the atomistic structure of Pt catalyst nanoparticles using HRTEM (high-resolution transmission electron microscopy). The particles exhibit a faceted, cubo-octahedral shape, extended planar defects, and mono-atomic surface steps. HRTEM imaging with negative spherical aberration yielded atomic-resolution images with a minimum of artifacts. Combining digital image processing, quantitative image analysis, and HRTEM image simulations to determine local variations of the spacing between neighboring Pt atom columns, we have found an expansion of the lattice parameter in the particle core and even larger, locally varying expansion of Pt–Pt next-neighbor distances at the particle surface. The latter likely originates from an amorphous oxide on the nanoparticle surface and/or dissolution of oxygen on subsurface sites. These structural features may significantly impact the catalytic activity of Pt nanoparticles. [Copyright &y& Elsevier]

Abstract: Clustering is a fundamental data analysis method. It is widely used for pattern recognition, feature extraction, vector quantization (VQ), image segmentation, function approximation, and data mining. As an unsupervised classification technique, clustering identifies some inherent structures present in a set of objects based on a similarity measure. Clustering methods can be based on statistical model identification () or competitive learning. In this paper, we give a comprehensive overview of competitive learning based clustering methods. Importance is attached to a number of competitive learning based clustering neural networks such as the self-organizing map (SOM), the learning vector quantization (LVQ), the neural gas, and the ART model, and clustering algorithms such as the -means, mountain/subtractive clustering, and fuzzy -means (FCM) algorithms. Associated topics such as the under-utilization problem, fuzzy clustering, robust clustering, clustering based on non-Euclidean distance measures, supervised clustering, hierarchical clustering as well as cluster validity are also described. Two examples are given to demonstrate the use of the clustering methods. [Copyright &y& Elsevier]

Abstract: The microstructure of abnormal grains in BaTiO3 based ceramics suggests that 2D nucleation and lateral growth take place in the material. High-resolution transmission electron microscopy investigation reveals that nucleation takes place at triple junctions of abnormal grain and adjacent matrix grains, subsequently form steps and the steps grow laterally along {111} planes of the abnormal grains. The abnormal grain boundaries are faceted in the growth direction, however, the ledges, which possess boundaries deviated from low-index crystallographic planes of the abnormal grains, could provide high mobility necessary for abnormal grain growth. [Copyright &y& Elsevier]

Abstract: Polycrystalline ZnGeN2 was synthesized by a new method, via vapor growth from Zn and Ge with thermal cracking of NH3. Measured lattice parameters indicate a monoclinic structure with a=b=0.3157±0.0024nm, c=0.5137±0.0021nm, and γ=119°30′±22′, consistent with previous reports. Planar stacking faults lying on the (001) plane were identified by transmission electron microscopy. Analysis indicates that these stacking faults are bound by a prismatic dislocation loop having in-plane and out-of-plane Burgers vector components of (a/3[11¯0]) and (c/2[001]), respectively. Photoluminescence spectroscopy at low temperature (∼4K) showed broad “yellow-band” impurity luminescence centered around 2.6eV and a narrower near-band-edge luminescence peak at 3.40±0.01eV. The near-band-edge luminescence peak is higher in energy by approximately 50meV, and higher in efficiency by at least two orders of magnitude than any previously reported. These observations indicate that this material has superior optical quality than previously obtained by other growth methods. The temperature dependence of the near-band-edge luminescence efficiency is consistent with excitons bound to a shallow donor band. [Copyright &y& Elsevier]

Abstract: Aiming to determine the contrast mismatch factor i.e. the Stobbs factor between the experimental and simulated high-resolution transmission electron micrographs, we have systematically compared the experimental images and simulations of a cleaved silicon sample for a series of focal settings and specimen thicknesses. For zero-loss energy filtered images, a mismatch factor of about 1.5–2.3 is measured for the image contrast, where the mismatch factor is focal dependent and higher mismatch appears around the focus value of 10nm. Attention is also given to the effects of the sample vibration and drift to the image contrast and pattern of the high-resolution micrographs. [Copyright &y& Elsevier]

Abstract: Precise knowledge of crystal thickness and orientation is critical for reliable interpretation of high-resolution transmission electron micrographs. In this paper, we propose a criterion of S 2 (T, u, v), which measures the crystal thickness by intensity matching of the selected-area Fourier transform of experimental holograms with the calculated electron diffraction pattern at a series of trial thicknesses (T) and crystal tilts (u, v). This criterion has been demonstrated successfully for local thickness determination from a simulated high-resolution image of a wedge-shaped YBa2Cu3O7−δ and from an experimental hologram of a Si crystal. [Copyright &y& Elsevier]

The effect of Pt additive on the microstructure and electrochemical properties of synthesized LiCoO2-based material was investigated. Besides incorporating into LiCoO2 lattice in small amounts, Pt additive induces dispersed Li2PtO3 and Pt in the LiCoO2 matrix to form multi-phase composites. In comparison with the single phase of LiCoO2, the multi-phase composite shows improved rate performance and cycleability at high rates. This improved rate behaviors can be attributed to the enhanced diffusion of Li+, which are caused by the enlarged c axis of LiCoO2 lattice due to Pt incorporating and fast diffusion paths of Li+ provided by the interfaces among in LiCoO2, Li2PtO3 and Pt. The dispersed Li2PtO3 and Pt are also beneficial to the cycleability. [Copyright &y& Elsevier]

The influence of secondary Y211 phase on the oxygen diffusion in the ceramic composite of Y123 with Y211 addition has been investigated by the isothermal electric resistance relaxation. The activation energy of oxygen diffusion in the Y123 matrix of the composite is obtained as 1.13, 1.04 and 0.97 eV for the composite of Y123 with x mol Y211, x=0, 0.2, 0.4 respectively, i.e., it is decreased with the Y211 addition in the investigated composition range. [Copyright &y& Elsevier]

Nano- and submicrometer LiMn2O4 spinel particles were successfully synthesized by a modified citrate route with spontaneous combustion at 250 °C followed by a calcination process. Citric acid was used as the chelating and combustion-assistant agent. The synthesized LiMn2O4 showed a high electrochemical performance compared with commercial LiMn2O4 materials. The initial discharge specific capacity reached 130 mAh/g. The effects of the processing factors and element substitution on the microstructure and electrochemical performance of LiMn2O4 were also examined. [Copyright &y& Elsevier]