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Purpose: Nasal pain, as an epileptic aura, has been poorly recognized. This study aims to demonstrate clinical features of patients with epilepsy who have nasal pain as an aura.Methods: We retrospectively investigated consecutive patients who visited the epilepsy clinic of tertiary hospital from April 2000 to September 2019. All included patients underwent epilepsy-dedicated, high-resolution magnetic resonance imaging (MRI) examinations. All MRI studies were analyzed by visual inspection.Results: Seven patients who presented nasal pain as an aura, were identified. Four patients reported nasal pain as the first aura. Four patients had right amygdala enlargement (isolated amygdala enlargement in three patients; amygdala enlargement in addition to hippocampal sclerosis in one patient), and one patient with compression of an internal carotid-posterior communicating artery aneurysm to right amygdala on brain MRI. Interictal epileptiform or ictal discharges on EEG were found in the right temporal region in five patients. In all four patients with amygdala enlargement, amygdala enlargement was ipsilateral to EEG anomalies. In all patients, nasal pain was accompanied by ictal semiological features, such as autonomic, olfactory, abdominal, or psychic auras, and focal impaired awareness seizures, which are typically associated with mesial temporal lobe epilepsy.Conclusions: Our findings suggest that nasal pain can occur as an epileptic aura in patients with temporal lobe epilepsy with probable involvement of the amygdala. [ABSTRACT FROM AUTHOR]

Abstract To expand the processing options for low-temperature-operating solid oxide fuel cells (LT-SOFCs), the hybridization of powder processing and vacuum deposition is attempted. Nanostructured nickel-yttria-stabilized zirconia (Ni-YSZ) anode functional layer (AFL) and YSZ/gadolinia-doped ceria (GDC) bi-layer electrolyte are fabricated over a sintered anode support by pulsed laser deposition (PLD), a physical vapor deposition technology. The most common powder-processed (screen-printed and sintered) La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -Gd 0.1 Ce 0.9 O 1.95 (LSCF-GDC) composite cathode is applied over vacuum-deposited thin-film components. When LSCF-GDC is sintered at a general sintering temperature of 1050 °C then the continuity of the GDC buffer is lost and excessive interdiffusion between the cathode and the electrolyte has occurred at the interface. On the other hand, if the sintering temperature is lowered to 950 °C, peak power density more than 1.7 W cm−2 at 650 °C is obtained. Moreover, the operation stability of the hybrid SOFC (degradation rate ∼8%/100 h) is superior to that of the SOFC with a vacuum-processed nanostructure cathode (degradation rate ∼21%/100 h) when exposed to 0.7 A cm−2 at 650 °C, which is a significantly harsh degradation test condition for LT-SOFCs. [ABSTRACT FROM AUTHOR]

Hydro-electric technology has gathered much attention by the virtue of water as the energy source. However, the low energy density of this technology severely limits its practical use. Here, we demonstrate a PEDOT:PSS-based transpiration-driven electrokinetic power generator (p-TEPG) that enables the utilization of a wider variety of real-world water resources for maximizing energy generation efficiencies. In addition to the conventional electrical double layer on the material surface, the p-TEPG builds an additional potential difference in the polymer matrix by the selective penetration of cations into the matrix that contains sulfonate functional groups. p-TEPG exhibits 80–250% higher energy density than carbon-based TEPG at the same resistance. Moreover, seawater produced enhanced volumetric energy/power densities (34.36 mJ cm−3 and 44.70 μW cm−3) and areal energy/power densities (410 μJ cm−2 and 0.45 μW cm−2), respectively, compared to DI water on a single p-TEPG device, which is sufficient to charge electrical energy storage systems and directly operate low-powered electronic. • p-TEPG maximizes energy harvesting efficiency by ion-permselective PEDOT:PSS. • Green water resources improve performance of p-TEPG. • p-TEPG adsorbs more cations into its polymer matrix by sulfonate groups. • p-TEPG can increases energy harvesting efficiency by using anions and cations with smaller radii. • p-TEPG can be fueled with seawater, demonstrating its potential for blue energy generating system. [ABSTRACT FROM AUTHOR]

A size effect study was conducted on [001] oriented vanadium nanopillars that were synthesized from both a thin film and a bulk crystal. The results indicate that a size-dependent deformation behavior exists for vanadium; the smaller nanopillars displayed discrete strain bursts and higher stresses during deformation. The size effect exponent is found to be 0.79, and the results are compared with previous reports on other body-centered cubic (bcc) metals: Nb, Ta, Mo and W. [ABSTRACT FROM AUTHOR]

Abstract: Multilayer thin films with bilayer thicknesses in the nanometer range have been reported to have very high strengths. A previous study has shown that Al–Al3Sc multilayers, with bilayer thicknesses as small as 6nm, have hardnesses as high as ∼3GPa as measured by sharp tip nanoindentation. In the present study, we have avoided some of the complications associated with sharp tip nanoindentation by directly measuring the yield strengths and strain hardening/softening properties of Al–Al3Sc multilayers using microcompression testing methods with a nanoindenter. The results show the expected trend of increasing yield strength with decreasing bilayer thickness, and compare favorably with estimates of the yield strengths based on sharp tip nanoindentation. During deformation, the Al–Al3Sc multilayer pillars with smaller bilayer spacings experience considerable strain softening, resulting in a “flat-top mushroom” shape after deformation. We have developed a numerical model to account for this inhomogeneous deformation behavior and to calculate stress–strain relationships during strain softening. A new transmission electron microscopy study of a deformed pillar shows that the softening is a result of destruction of the layered structure due to shearing and rotation. [Copyright &y& Elsevier]

Abstract: The size-dependent strength of face-centered cubic (fcc) metals, as revealed by uniaxial compression of nanopillars, suggests that plasticity is dislocation source-controlled, with fewer sources in smaller pillars producing a “smaller is stronger” effect. To further investigate this phenomenon we have studied the effects of prestraining and annealing on the deformation properties of [001] Au nanopillars. By making pillars from an epitaxial film of [001] Au on [001] MgO, using focused ion beam machining, we are able to create both puck-shaped pillars that can be stably prestrained and pillars with a high aspect ratio, which can be tested in uniaxial compression. We find that prestraining dramatically reduces the flow strength of nanopillars while annealing restores the strength to the pristine levels. These unusual effects are not seen in bulk fcc metals, which behave in the opposite way. We discuss their possible causes in terms of dislocation densities using transmission electron microscopy. [Copyright &y& Elsevier]

Abstract: Nanoindentation has developed as a practical tool for determining the mechanical properties of thin films. In this paper, we develop a method for determining the hardness of thin films on substrates based on measurements of the contact stiffness vs. depth of indentation and prior knowledge of the elastic properties of the film and substrate. The method utilizes an analysis of contact stiffness vs. contact area for purely elastic indentation to correct for the effects of surface roughness and pile-up/sink-in on the contact area during elastic–plastic indentation of elastically mismatched film/substrate systems. We find the hardness to be essentially depth independent for indentation depths approaching the thickness of the film for several thin film/substrate systems. This new technique is described in detail and is applied to the nanoindentation of compliant films on stiff substrates (Al/Si and Al/sapphire) and stiff films on compliant substrates (W/Si and W/glass). [Copyright &y& Elsevier]

Abstract: In this paper, we describe an on-going effort to develop a thin film combinatorial method for identifying alloy compositions of potential interest as structural materials. To investigate this idea, compositionally graded Ti–Al thin films have been sputter deposited onto Si substrates, and the mechanical properties of the “library” of compositions are then probed using nanoindentation. This combinatorial method offers the possibility of rapidly varying the compositions and microstructures of alloys and quickly determining the compositions and microstructures of greatest interest for further development as bulk structural alloys. Nanoindentation experiments are used to extract the properties of the film so that the bulk properties of the material may be estimated. A new method for extracting the hardness of films on substrates from nanoindentation experiments has been developed and is applied to the compositionally graded Ti–Al thin films. Together with the nanoindentation data and a compositional analysis, we are able to establish a relationship between the hardness of the film and the composition. We discuss the results of these combinatorial experiments in connection with estimating the properties of bulk materials. [Copyright &y& Elsevier]

Piezoelectric materials are suitable for haptic technology as they can convert mechanical stimuli into electrical signals and vice-versa. However, owing to their disadvantageous mechanical properties such as brittleness (in ceramics) and a low piezoelectric coefficient (in polymers), their application in haptic technology remains challenging. In this paper, we introduce a truss-like 3D hollow nanostructure using zinc oxide (ZnO) that exhibits a drastically improved elastic strain limit while maintaining a piezoelectric coefficient similar to that of single-crystal ZnO. The ZnO hollow nanostructure was fabricated using proximity field nanopatterning (PnP) and atomic layer deposition (ALD) at four different processing temperatures. The piezoelectric characteristics were analyzed through dual AC resonance tracking piezoresponse force microscopy (PFM), and the piezoelectric coefficient was measured to be up to 9.2 pm/V. The nanopillar compression test result showed that the measured elastic strain limit of approximately 10% was at least 3 times greater than the previously reported value. The extended elastic limit of the 3D hollow structure was further supported by finite element simulations. The ZnO hollow nanostructure shows excellent potential for its application to enhanced haptic devices, which mimic the human sense of touch. A 3D ZnO hollow nanostructure exhibits an improved elastic strain limit while maintaining a piezoelectric coefficient similar to that of single-crystal ZnO. This nanostructure is fabricated using atomic layer deposition at four different temperatures. The piezoelectric coefficient of ≈ 9.2 pm/V and elastic strain limit of ≈ 10% are measured by piezoresponse force microscopy and nanopillar compression test, respectively. Image 1 • We developed a 3D ZnO hollow nanostructure through atomic layer deposition and 3D nanolithography. • The effective piezoelectric coefficient of 3D ZnO hollow nanostructure is close to that of a single-crystal bulk ZnO. • The 3D ZnO hollow nanostructure has a high elastic strain limit of 10% which is 3 times greater than the bulk ZnO value. • Our 3D hollow nanostructure can be used in enhanced haptic devices, which mimic the human sense of touch. [ABSTRACT FROM AUTHOR]

In this study, graphene was physically patterned to allow for Cu-Cu contacts to serve as anchoring points, thereby preventing complete delamination at the interface, and the effect of the inclusion of Cu-Cu contacts on bending fatigue response was evaluated. Direct patterning and roll-based dry transfer process of CVD-grown graphene was used to fabricate patterned Cu-Gr nanolayered composites. Bending fatigue tests were performed to determine the optimal configuration of patterning that can lead to enhanced reliability. The graphene was shown to hinder crack formation and propagation, where the cracks were absorbed at the graphene interface through localized delamination while the patterned area with Cu-Cu contact served as anchoring points to prevent macroscopic delamination. Therefore, the optimized graphene patterning design proposed in this study was shown to provide a good balance in crack absorption at the interface and prevention of global delamination that can significantly enhance the reliability under bending fatigue. [Display omitted] [ABSTRACT FROM AUTHOR]

Micro-architectures, such as cellular truss structures, enhance the mechanical properties of structural materials while ensuring that they are lightweight in nature. Among others, stretching-dominated truss structures are known for their high modulus and yield strength, which makes them the best choice for lightweight structural applications. Finite element analysis of octahedral vs. octet structures is used to compare the differences in stress distribution in the stretching-dominated deformation of such trusses. Both octahedral and octet stretching-dominated structures were fabricated by fused deposition modeling (FDM)-based three-dimensional (3D) printing. These micro-architectures are printed with different polymeric materials, such as polylactic acid or polylactide (PLA), nylon 618, and a carbon fiber reinforced composite of PLA (CFRPLA). In addition, the CFRPLA filament with randomly suspended carbon fibers in PLA undergoes shear-induced alignment along the strut direction of the 3D printed micro-trusses, which leads to an improved Young's modulus as compared to the other materials. The properties of the 3D printed stretching-dominated micro-trusses are evaluated by compression testing, finite element analysis (FEA), and thermal analysis. The 3D printed octet structure of CFRPLA with fiber alignment exhibits the highest modulus and yield strength of 0.6 GPa and 17 MPa, respectively. [ABSTRACT FROM AUTHOR]

In this study, time-dependent plastic deformation of micropillars fabricated from low melting point metal Sn (~ 505 K) was investigated at room temperature. Size-dependent strength was first evaluated and creep tests were then performed on the micropillars having diameters of 1 and 5 μm. Sn pillars showed significant creep deformation, and creep rate was independent of pillar size. Creep stress exponent was determined to be ~ 1, and negligible effect of e-beam irradiation on creep rate confirmed that the lattice diffusion must be the predominant creep mechanism. Creep deformation of Sn micropillars, therefore, differs from the dislocation-climb based creep in bulk Sn. [ABSTRACT FROM AUTHOR]

Abstract The effect of varying the density of Ag nanowire networks on their reliability was explored during cyclic bending. The reliability of the Ag nanowire network was degraded as the density of nanowires decreased, which is in contrast to E-beam evaporated dense Cu thin films that showed enhanced reliability for thinner films. The cause for such a reverse trend is explained by a percolation mechanism considering that the failure in the Ag nanowire network occurs locally at the junctions that are randomly distributed as opposed to fatigue-induced channel crack formation in a Cu thin film. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

In-situ transmission electron microscopy (TEM) annealing of submicron Al pillars (∼300–450 nm in diameter) fabricated by focused ion beam (FIB) shows that the dislocation loops formed by the high energy Ga + ion beam impact near the material surface can be removed by annealing at around half of the melting point ( T m ). Quantitative analysis of real-time TEM data reveals that the dislocation loops first show a ripening behavior at around 0.4 T m , i.e. larger loops coarsen at the expense of smaller ones. Subsequently, the ripened loops start to shrink and are eventually annihilated at ∼0.5 T m by the diffusion of thermally activated vacancies. Microcompression tests on the as-fabricated and annealed pillars suggest that the FIB-induced defects, particularly dislocation loops, distinctively affect the deformation behavior of submicron Al pillars; while the yield and flow stresses appear unaffected by the annealing, strain bursts are larger and more frequent in the annealed pillars compared to those of as-fabricated samples. In-situ TEM compression revealed that the initial plastic deformation and subsequent plastic flow of Al pillars are significantly altered by the presence of FIB-induced dislocation loops, as they actively respond to the applied stress. We observe that the initial dislocation activity in most FIB-prepared pillars was the glide of FIB-induced dislocation loops. With further straining, the dislocation loops escaped the pillar, leaving slip steps at the pillar surface and/or dislocation debris within the pillar volume via the interaction with other mobile dislocations. The subsequent dislocation slip is mostly localized at these locations, thereby forming large slip steps. Contrarily, in the case of annealed pillars, the deformation was rather homogeneous with the formation of multiple fine slip steps. The present direct TEM observations contribute to the understanding of the nature of FIB-induced defects and reveal their distinct roles in the deformation behaviors of submicron pillars. [ABSTRACT FROM AUTHOR]

The effect of inclusion of a grain boundary in nanopillar was studied using Al bicrystal with [3 4 3]/[ 13 17 ‾ 14 ] orientation. Ex situ compression results showed higher strengths in bicrystal pillars than in single crystal pillars, which is explained with respect to the reduced single-armed source length that was confirmed in the in situ TEM tests. Molecular dynamics simulations indicated that the grain boundary can assist in dislocation nucleations without resulting in dislocation pile-up at the boundary. [ABSTRACT FROM AUTHOR]

Microstructural evolution of focused ion beam machined Mg nanopillars was investigated by in situ heating experiments in a transmission electron microscope. The dislocation loops generated by a Ga+ ion beam were annihilated at around half of the melting point of Mg. At a higher temperature (673K), the sublimation of Mg occurred due to the reduced stability of Mg under the vacuum environment. In the course of sublimation, the Ga-rich liquid was formed and stabilized the structural instability of moving solid–vapor interface. [ABSTRACT FROM AUTHOR]

Abstract: External stresses are applied during operation or storage in flexible electronics, which makes understanding time-dependent plastic deformation of nanobuilding blocks more crucial for ensuring the reliability of the devices. Here, we systematically explored the time-dependent nanoscale plasticity of single-crystal ZnO nanorods and its size effects. A series of compression creep tests under different low stresses (in elastic regime) were performed on vertically oriented rods having equivalent diameters in the range of ∼200 to ∼2000nm. It was revealed that creep indeed occurs in the rods even at ambient temperature, and is more pronounced in smaller nanorods. Analyzing the stress exponent and the activation volume suggests that the enhanced plasticity may be controlled by the diffusion creep (through the “space-charge layer” near the surface and/or along the interface between the punch and the top surface of the rod), which is supported by the results from in situ creep tests under electron-beam irradiation and in situ electric measurements. [Copyright &y& Elsevier]

Although foldable electronic devices have been commercially available for some time now, flexible protective coating with sufficient reliability is yet to be achieved. The integration of polyurethane acrylate and an organic-inorganic (O-I) siloxane hybrid is proposed in this study as a promising protective coating, where both high strength and stretchability could be achieved to allow for the needed reliability for foldable electronics. In this work, a urethane-methacrylate siloxane hybrid (U-MSH) composite was fabricated by a physical blending of methacrylate-functionalized oligosiloxane and acrylate terminated urethane prepolymer followed by curing. The U-MSH composite demonstrates excellent performance in terms of optical (e.g., transmittance, Abbe number, UV stability) and mechanical properties (e.g., resilience under compression, tension, and scratch). These outstanding properties can be attributed to the synergetic effect of the combined polyurethane acrylate and O-I siloxane hybrid. Excellent reliability of U-MSH coating film is successfully demonstrated using an outward-bending test, suggesting that U-MSH has great potential as a protective material for flexible electronics. • UV-curable acrylate-terminated urethane prepolymer was synthesized via urethane formation reaction. • Methacrylate-functionalized siloxane resin was synthesized via sol-gel reaction. • Highly transparent urethane-methacrylate siloxane hybrid composite (U-MSH) material was successfully fabricated. • U-MSH exhibited the excellent performance in tensile, compression and scratch tests. • U-MSH coating film is demonstrated without shrinkage/cracking and endured outward-bending test. [ABSTRACT FROM AUTHOR]

Abstract: Indium columnar structures with diameters near 1μm were deformed by uniaxial compression at strain rates of approximately 0.01 and 0.001s−1. Defect density evolution in the nanopillars was evaluated by applying synchrotron Laue X-ray microdiffraction (μSLXRD) on the same specimens before and after deformation. Results of the μSLXRD measurements indicate that the dislocation density increases as a result of mechanical deformation and is a strong function of strain rate. These results suggest that the rate of defect generation during the compression tests exceeds the rate of defect annihilation, implying that plasticity in these indium nanostructures commences via dislocation multiplication rather than nucleation processes. This is in contrast with the behaviors of other materials at the nanoscale, such as, gold, tin, molybdenum, and bismuth. A hypothesis based on the dislocation mean-free-path prior to the multiplication process is proposed to explain this variance. [Copyright &y& Elsevier]

Abstract: The biaxial modulus and the coefficient of thermal expansion (CTE) of Ge2Sb2Te5 (GST) films with the thickness of 300 nm were characterized using the substrate curvature method on two different substrates. The elastic modulus of the GST films was also separately determined using nanoindentation. Measured biaxial modulus and CTE from substrate curvature method were 29.5±1.87 GPa and (13.3±1.39)×10−6 K−1 for the amorphous state and 36.8±1.54 GPa and (17.4±1.21)×10−6 K−1 for the crystalline state. The elastic moduli determined using nanoindentation for the amorphous and crystalline states were 33.9±0.67 GPa and 58.7±0.48 GPa, respectively. Based on the results of the thermomechanical properties, the stresses in the phase-change random access memory (PRAM) structures were calculated using finite element analysis (FEA) considering the thermal and the phase-change stress. The FEA simulations showed that the thermal stress is higher in magnitude than the phase-change stress in a PRAM structure, but the gradient of the phase-change stress is higher than the gradient of the thermal stress. [Copyright &y& Elsevier]

A strategy for improving the stability of nickel-based solid oxide fuel cell (SOFC) anodes via compositional and microstructural engineering is presented. Ni content was reduced to 2 vol%, and nanosized Ni particles were uniformly dispersed in a mixed ionic-electronic conducting matrix comprising gadolinium-doped ceria (GDC) using a thin-film technique. Remarkable stability with no performance deterioration even after 100 reduction-oxidation cycles could be observed for the optimized nanostructured anodes. Cell performance at 500°C was enhanced, exceeding 650 mW/cm2. This study offers valuable insights for enhancing the durability, performance, and productivity of SOFCs. Image, graphical abstract [ABSTRACT FROM AUTHOR]