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Background: Cerebral embolism in patients with non-valvular atrial fibrillation (NVAF) is mainly caused by thrombus formation in the left atrial appendage. D-dimer is known to reflect the thrombogenic activity of the left atrium in NVAF patients. This study aimed to investigate the relationship between D-dimer levels and infarct pattern in ischemic stroke patients with NVAF. Methods: We enrolled 255 patients who developed cardioembolic stroke caused by NVAF and presented to the hospital within 7 days. We divided the infarct pattern into two groups: single lesions (SL) and multiple lesions (ML). The infarct pattern was also classified into two groups: ischemic lesions involving a single vascular territory (ST) and multiple vascular territories (MT). We analyzed the relationship between the infarct pattern and D-dimer levels. Results: Of the 255 patients, 79 (31.0%) and 176 (69.0%) were in the SL and ML groups, respectively. In addition, 207 (81.2%) and 48 (18.8%) patients were classified into the ST and MT groups, respectively. Compared with the SL group, a higher D-dimer level was observed in the ML group (p=0.006). Similarly, the MT group had higher D-dimer levels than the ST group (p=0.001). Logistic regression analysis showed that elevated D-dimer levels were significantly and independently associated with the presence of multiple ischemic lesions (p=0.021) and the involvement of multiple vascular territories (p=0.020). Conclusions: This study showed that elevated D-dimer levels were independently associated with multiple ischemic lesions involving multiple vascular territories in ischemic stroke patients with NVAF.

Background: Multiple system atrophy (MSA) is a sporadic neurodegenerative disease characterized by various combinations of parkinsonism, cerebellar ataxia, autonomic dysfunction and pyramidal signs. Two clinical subtypes are recognized: MSA with predominant cerebellar ataxia (MSA-C) and MSA with predominant parkinsonism (MSA-P). The aim of this study was to compare pathological features between MSA-C and MSA-P.Methods: Two autopsy confirmed cases with MSA were included from the Pusan National University Hospital Brain Bank. Case 1 had been clinically diagnosed as MSA-C and case 2 as MSA-P. The severity of neuronal loss and gliosis as well as the glial and neuronal cytoplasmic inclusions were semiquantitatively assessed in both striatonigral and olivopontocerebellar regions. Based on the grading system, pathological phenotypes of MSA were classified as striatonigral degeneration (SND) predominant (SND type), olivopontocerebellar degeneration (OPC) predominant (OPC type), or equivalent SND and OPC pathology (SND=OPC type).Results: Both cases showed widespread and abundant α-synuclein positive glial cytoplasmic inclusions in association with neurodegenerative changes in striatonigral or olivopontocerebellar structures, leading to the primary pathological diagnosis of MSA. Primary age-related tauopathy was incidentally found but Lewy bodies were not in both cases. The pathological phenotypes of MSA were MSA-OPC type in case 1 and MSA-SND=OPC type in case 2.Conclusions: Our data suggest that clinical phenotypes of MSA reflect the pathological characteristics.

The article deals with research related to the issues of nanomodification of elastomers as a basis of electric heaters with self-regulating temperature. The effect of multistage mechanical activation of multilayer carbon nanotubes (MCNTs) with graphite on the uniformity of the temperature field distribution on the surface of nanomodified organosilicon elastomer has been studied. The influence of the stages of mechanical action on the parameters of MCNTs is revealed. It has been ascertained that for the MCNTs/graphite bulk material, which has passed the stage of mechanical activation in the vortex layer apparatus, a more uniform distribution of the temperature field and an increase in temperature to 57.1 °C at the supply voltage of 100 V are typical. The distribution of the temperature field in the centrifugal paddle mixer “WF-20B” for mixing MCNTs with graphite has been investigated. It has been found that there is also a thermal effect in addition to the mechanical action on the MCNTs in the paddle mixer “WF-20B”. The thermal effect is associated with the transfer of the mechanical energy of friction of the binary mixture MCNTs/graphite on the paddle and the walls of the vessel. The multiplicity of the starting current Ip to the nominal In (Ip/In) is 5 for the first sample, 7.5 for the second sample, and 10 for the third sample at the supply voltage of 100 V. The effect of reducing the starting current and stabilizing the temperature indicates the presence of self-regulation, which is expressed in maintaining a certain level of temperature.

Exactly 50 years ago, the first article on electrochromism was published. Today electrochromic materials are highly popular in various devices. Interest in nanostructured electrochromic and nanocomposite organic/inorganic nanostructured electrochromic materials has increased in the last decade. These materials can enhance the electrochemical and electrochromic properties of devices related to them. This article describes electrochromic materials, proposes their classification and systematization for organic inorganic and nanostructured electrochromic materials, identifies their advantages and shortcomings, analyzes current tendencies in the development of nanomaterials used in electrochromic coatings (films) and their practical use in various optical devices for protection from light radiation, in particular, their use as light filters and light modulators for optoelectronic devices, as well as methods for their preparation. The modern technologies of “Smart Windows”, which are based on chromogenic materials and liquid crystals, are analyzed, and their advantages and disadvantages are also given. Various types of chromogenic materials are presented, examples of which include photochromic, thermochromic and gasochromic materials, as well as the main physical effects affecting changes in their optical properties. Additionally, this study describes electrochromic technologies based on WO3 films prepared by different methods, such as electrochemical deposition, magnetron sputtering, spray pyrolysis, sol–gel, etc. An example of an electrochromic “Smart Window” based on WO3 is shown in the article. A modern analysis of electrochromic devices based on nanostructured materials used in various applications is presented. The paper discusses the causes of internal and external size effects in the process of modifying WO3 electrochromic films using nanomaterials, in particular, GO/rGO nanomaterials.

This paper presents an analytical study on the dynamic stability of carbon nanotubes (CNTs) reinforced functionally graded composite beams when subjected to axial excitation loading. The composite beams are functionally graded using a I-type CNTs reinforcement. The section properties of the non-uniform functionally graded composite beams are assessed using Halpin–Tsai model. The analysis of dynamic stability of the composite beams is performed by using Bolotin’s method. Analytical expressions of determining free vibration frequency, critical buckling load, and excitation frequency of the non-uniform functionally graded composite beams are derived, in which both the shear deformation and rotary inertia effects are considered. The study demonstrates that the dynamic stability of the beam can be improved significantly when it is functionally graded using the I-type CNTs reinforcement.

Global warming, one of the most serious aspects of climate change, can be expected to cause rising sea levels. These, in turn, have been linked to unprecedentedly large typhoons that can cause flooding of low-lying land, coastal invasion, seawater flows into rivers and groundwater, rising river levels, and aberrant tides. To prevent loss of life and property damage caused by typhoons, it is crucial to accurately estimate storm surge related risk. This study therefore develops a statistical model for estimating probability model, based on surge data pertaining to Typhoon Maemi, which struck South Korea in 2003. Specifically, estimation of non-exceedance probability models of the typhoon-related storm surge was achieved via clustered separated peaks-over-threshold simulation, while various distribution models were fitted to the empirical data for investigating the risk of storm surge height. The result of this process found that the result of Weibull distribution was better than other distribution model for Typhoon Maemi's peak total water level.

The familial Creutzfeldt-Jakob disease (fCJD) usually has similar clinical and neuroimaging features as sporadic CJD (sCJD). A 57-year-old man presented with a four-month history of rapidly progressive dementia (RPD). Laboratory tests for RPD were all normal. Brain MRI demonstrated diffuse cortical atrophy and no abnormal cortical or striatal hyperintensities on fluid-attenuated inversion recovery (FLAIR)/diffusion weighted imaging (DWI). Electroencephalography revealed intermittent slow waves in the bilateral hemispheres. Cerebrospinal fluid (CSF) examination showed elevated cell counts and protein concentrations. After 10 days of empirical treatment with antiviral agents, the patient was eventually diagnosed with fCJD with M232R mutation based on the results of positivity for 14-3-3 protein, CSF PrPsc in real-time quaking-induced conversion assay and genetic test for PRNP gene. The striatal or cortical FLAIR/DWI hyperintensities are reliable radiographic markers in the diagnosis of both sCJD and fCJD. However, this case suggests that clinical work-up for CJD including genetic test is essential to do a differential diagnosis of RPD, regardless of FLAIR/DWI findings.

In this paper an analytical prediction model is developed to determine the percolation threshold and effective properties of carbon nanotubes reinforced two-phase composite materials. The model considers the effect of not only volume fraction but also aspect ratio and mixed pattern of fibres in the composites. It is shown that the effect of fibres on the effective properties of the composites can be characterised in terms of three different zones, namely non-percolated zone, partially percolated zone, and fully percolated zone. The formulations for determining percolation threshold and effective properties of the composites in the three different zones are derived. The model is validated by using available experimental data to demonstrate its appropriateness and reliability.

In this paper an analytical prediction model for the heat transfer analysis of two-phase composite materials is developed. Formulations for the effective density, effective specific heat and effective thermal conductivity of the composite materials are derived. The present model considers not only the effect of interfacial thermal resistance between CNTs and polymer matrix but also the influence of fibre aspect ratio of CNTs on the effective thermal conductivity of the composites. The validation of the model is also provided by using available experimental data to demonstrate the appropriateness and reliability of the present model.

Introduction: A significant portion of patients with acute minor stroke have poor functional outcome due to early neurological deterioration (END). The purpose of this study is to investigate the applicability of machine learning algorithms to predict END in patients with acute minor stroke. Methods: We collected clinical and neuroimaging information from patients with acute minor stroke with NIHHS score of 3 or less. Early neurological deterioration was defined as any worsening of NIHSS score within three days after admission. Poor functional outcome was defined as a modified Rankin Scale score of 2 or more. We also compared clinical and neuroimaging information between END and No END group. Four machine learning algorithms, i.e., Boosted trees, Bootstrap decision forest, Deep learning, and Logistic Regression, are selected and trained by our dataset to predict early neurological deterioration Results: A total of 739 patients were included in this study. Seventy-eight patients (10.6%) had early neurological deterioration. Among 78 patients with END, 61 (78.2%) had poor functional outcomes at 90 days after stroke onset. On multivariate analysis, NIHSS score on admission (P=0.003), hemorrhagic transformation(P=0.010), and stenosis (P=0.014) or occlusion (P=0.004) of a relevant artery were independently associated with END. Compared with four machine learning algorithms, Boosted trees, Deep learning, and Logistic Regression achieved an excellent prediction of END in patients with acute minor stroke (Boosted trees: accuracy = 0.966, F1 score = 0.8 and an area under the curve value = 0.934, Deep learning :0.966, 0.8, 0. 904, and Logistic Regression : 0.966, 0.8, 0.885). Conclusions: This study suggests that machine learning algorithms which integrate clinical and neuroimaging information accurately predict END in patients with acute minor ischemic stroke. Further studies based on an extensive data set are needed to predict END accurately for treatment strategies and better functional outcome.

Introduction: Early neurological deterioration is one of the critical determinants of functional outcomes in patients with minor ischemic stroke. The purpose of this study was to identify predictors of early neurological deterioration in patients with acute minor ischemic stroke. Methods: A total of 739 patients with acute minor ischemic stroke who are admitted within 24 hours after onset of stroke symptom between January 2014 and December 2018 were enrolled in this study. We analyzed demographic characteristics, risk factors for vascular diseases, stroke severity, stroke subtypes, neuroimaging parameters, and relevant arterial steno-occlusive lesions. Early neurological deterioration was defined as any worsening of neurological deficits within 3 days after admission. Logistic regression was used to determine independent predictors of early neurological deterioration. Results: Seventy-eight of 739 (10.5%) patients had early neurological deterioration. Among 78 patients with early neurological deterioration, 61 (78.2%) had poor functional outcomes at 90 days after stroke onset. By contrast, 131 of 661 (19.8%) patients without early neurological deterioration had poor functional outcomes. Multivariate analysis identified hemorrhagic transformation (OR, 3.8; 95% CI, 1.4-10.5; P=0.010), higher score of NIHSS on admission (OR, 1.4; 95% CI, 1.1-1.7; P=0.003), relevant arterial stenosis (OR, 2.0; 95% CI, 1.2-3.5; p=0.014) and occlusion (OR, 2.6; 95% CI, 1.4-4.8; p=0.004) were the factors associated with early neurological deterioration. Conclusions: The results of this study suggest that hemorrhagic transformation, higher NIHSS score on admission, relevant arterial steno-occlusive lesions are independent predictors of early neurological deterioration in patients with acute minor ischemic stroke.

This paper reported the effect of high temperature on the electro-mechanical behavior of carbon nanotube (CNT) reinforced epoxy composites. CNT/epoxy composites were fabricated by dispersing CNTs in the epoxy matrix using a solution casting method. Electrical conductivity measurements obtained for the CNT/epoxy composites indicated a steadily increasing directly proportional relationship with CNT concentration with a percolation threshold at 0.25 wt %, reaching a maximum of up to 0.01 S/m at 2.00 wt % CNTs. The electro-mechanical behavior of CNT/epoxy composites were investigated at a room temperature under the static and cyclic compressive loadings, resulting that the change in resistance of CNT/epoxy composites was reduced as increasing CNT concentration with good repeatability. This is due to well-networked CNTs conducting pathways created within the solid epoxy matrix observed by scanning electron microscopy. Temperature significantly affects the electro-mechanical behavior of CNT/epoxy composites. In particular, the electro-mechanical behavior of CNT/epoxy composites below the glass transition temperature showed the similar trend with those at room temperature, whereas the electro-mechanical behavior of CNT/epoxy composites above the glass transition temperature showed an opposite change in resistance with poor repeatability due to unstable CNT network in epoxy matrix.

This paper presents an analytical model to describe the influence of mechanical deformation on the effective electrical conductivity of CNTs reinforced composites. The model shows that the effect of mechanical strain on the effective electrical conductivity of CNTs reinforced composites are via two mechanisms; one is the strain-induced alteration of volume fraction of inclusions and the other is the strain-induced change of the tunnelling electrical conductivity of inclusions. Analytical formulations are developed for calculating the dependence of the effective electrical conductivity of the composite on the mechanical strain. The model is validated by using experimental data published in literature for CNTs reinforced polymer composites.

Carbon nanotube (CNT)/cement composites have been proposed as a multifunctional material for self-sensing and traffic monitoring due to their unique electric conductivity which changes with the application of mechanical load. However, material constituent and environmental factors may significantly affect the potential application of these materials. Therefore, it is necessary to understand an influence of material constituent such as porosity and dispersion of CNT and environmental factor such as moisture on the electrical conductivity of CNT/cement composite. This paper investigates the effect of moisture on the effective electrical conductivity of CNT/cement composites. To prepare the specimens, multi-walled carbon nanotubes (MWCNTs) are well dispersed in cement paste, which is then molded and cured into cubic test specimens. By drying the specimens from the fully saturated state to the fully dry state, the effective electrical conductivity is measured at different moisture contents. As the water in the specimen is replaced by air voids, the electrical conductivity significantly decreases. Different ratios of MWCNTs to cement have been used in this study. Micromechanical models have been used to predict the effective electrical conductivities. A comprehensive model is proposed to take into account the effects of individual material phases on the effective electrical conductivity of CNT/cement composites with moisture effect.

The effective electrical conductivity of multi-walled carbon nanotube/polydimethylsiloxane composites with chain-structured ferromagnetic particles has been investigated by experiments and micromechanics-based modeling. A multi-scale modeling approach is used to consider different size of fillers of multi-walled carbon nanotubes and particles as well as their distribution in the matrix. At nanoscale, for multi-walled carbon nanotube/polydimethylsiloxane composite, eight-chain model and influence of waviness of multi-walled carbon nanotube are considered to render an effective electrical conductivity. At microscale, ferromagnetic particles are aligned in the matrix made of the multi-walled carbon nanotube/polydimethylsiloxane composite, and an analytical model is established based on representative volume element. The influence of inter-particle distance is evaluated. The proposed analytic results agree well with the experimental results. The present model can be a useful tool for design and analysis of these composites for sensing applications considering their percolation threshold and overall electrical conductivity.

This paper presents an analytical study on the electrical conductivity of composites whose constituted materials have distinct electrical properties. The present study investigates the effect of the aspect ratio of inclusions on the effective electrical conductivity of composites. Formulations are derived for determining the percolation threshold and calculating the electrical conductivity of composites with considering aspect ratio effect. The validation of the present model is also provided by using available experimental data. The present analytical model can be applied to predict the electrical behaviour of carbon-nanotube fibre reinforced polymer composites.

Joule heating is useful for fast and reliable manufacturing of conductive composite materials. In this study, we investigated the influence of Joule heating on curing conditions and material properties of polymer-based conductive composite materials consisting of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS). We applied different voltages to the CNT nanocomposites to investigate their electrical stabilization, curing temperature, and curing time. The result showed that highly conductive CNT/PDMS composites were successfully cured by Joule heating with uniform and fast heat distribution. For a 7.0 wt % CNT/PDMS composite, a high curing temperature of around 100 &deg, C was achieved at 20 V with rapid temperature increase. The conductive nanocomposite cured by Joule heating also revealed an enhancement in mechanical properties without changing the electrical conductivities. Therefore, CNT/PDMS composites cured by Joule heating are useful for expediting the manufacturing process for particulate conductive composites in the field of flexible and large-area sensors and electronics, where fast and uniform curing is critical to their performance.

We investigated the acoustic performance of electrostatic sound-generating devices consisting of bi-layer graphene on polyimide film. The total sound pressure level (SPL) of the sound generated from the devices was measured as a function of source frequency by sweeping, and frequency spectra were measured at 1/3 octave band frequencies. The relationship between various operation conditions and total SPL was determined. In addition, the effects of changing voltage level, adding a DC offset, and using two pairs of electrodes were evaluated. It should be noted that two pairs of electrode operations improved sound generation by about 10 dB over all frequency ranges compared with conventional operation. As for the sound-generating capability, total SPL was 70 dBA at 4 kHz when an AC voltage of 100 Vpp was applied with a DC offset of 100 V. Acoustic characteristics differed from other types of graphene-based sound generators, such as graphene thermoacoustic devices and graphene polyvinylidene fluoride devices. The effects of diameter and distance between electrodes were also studied, and we found that diameter greatly influenced the frequency response. We anticipate that the design information provided in this paper, in addition to describing key parameters of electrostatic sound-generating devices, will facilitate the commercial development of electrostatic sound-generating systems.

The switching mechanisms of resistive random access memories (ReRAMs) were strongly related to the formation and rupture of conduction filaments (CFs) in the transition metal oxide (TMO) layer. The novel method approached to enhance the electrical characteristics of ReRAMs by introducing of the local insertion of the low-k dielectric layer inside the TMO layer. Simulation results showed that the insertion of the low-k dielectric layer in the TMO layer reduced the switching volume and the generation of CFs. The large variation of resistive switching properties was caused by the stochastic characteristics of the CFs, which was involved in switching by generation and rupture. The electrical characteristics of the novel ReRAMs exhibited a low reset current of below 20 microA, the high uniformity of the resistive switching, and the narrow variation of the resistance for the high resistance state.

This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics.

This study was investigated physiological activities of enzyme hydrolysates in 80% ethanol extracts from sesame, black sesame and perilla cake. Total phenol contents in 80% ethanol extracts of sesame, black sesame and perilla cake were 116.90, 102.20 and 141.90 mg/g, respectively. Whereas total flavonoid contents were 64.10, 32.00 and 131.90 mg/g, respectively. Total phenol contents of enzyme hydrolysates in 80% ethanol extracts from sesame, black sesame and perilla cake were 413.30, 221.20 and 409.10 mg/g, respectively. Whereas total flavonoid contents were 361.80, 103.30 and 345.80 mg/g, respectively. Electron donating effects, nitrite-scavenging abilities, ferrous ion chelating effect and SOD-like activities increased by emzymatic hydrolysis. The order of Electron donating effects, nitrite-scavenging abilities and SOD-like activities by emzymatic hydrolysis was perilla > sesame > black sesame cake. And the order of nitrite-scavenging abilities(pH 1.2) was sesame > perilla > black sesame cake.

In this study, a method of evaluating and enhancing the visibility of graphene oxide on dielectric films was investigated. To evaluate the visibility in a multiwavelength range, we have suggested two parameters, the red, green, and blue (RGB) contrast and the RGB difference. By using these two parameters, researchers can easily determine whether the visibility comes from the color difference or from the intensity difference between the material and substrate. A high contrast image can be acquired by filtering the light source with color filters. It is predicted that the visibility of the graphene oxide monolayer may be three times as high under normal halogen light. By measurement, the visibility of graphene oxide on 70 nm Si3N4/Si increased 2.67±0.13 times under a green-filtered light. The calculated colors of graphene oxide from the RGB parameter can be effectively used to estimate the graphene oxide layer thickness and effective dielectric film thickness for high visibility graphene oxide.

Polycaprolactone/Pluronic F127 porous scaffolds are prepared using a modified melt-molding particulate-leaching method. The scaffolds are highly porous (about 90% porosity) and have open-cellular pore structures. Growth factors (TGF-β 2 , BMP-7 or dual TGF-β 2 /BMP-7) can be easily immobilized on the pore surfaces of the PCL/F127 scaffolds via binding with heparin. The growth-factor-immobilized scaffolds can induce the chondrogenesis of ATMSCs seeded onto them. Using TGF-β 2 and BMP-7 growth factors together leads to a better chondrogenic differentiation behavior than using single-growth-factor immobilized scaffolds.

Multifunctional polymer-based composites have been widely used in various research and industrial applications, such as flexible and stretchable electronics and sensors and sensor-integrated smart structures. This study investigates the influence of particle coalescence on the mechanical and electrical properties of spherical nickel powder (SNP)/polydimethylsiloxane (PDMS) composites in which SNP was aligned using an external magnetic field. With the increase of the volume fraction of the SNP, the aligned SNP/PDMS composites exhibited a higher tensile strength and a lower ultimate strain. In addition, the composites with aligned SNP showed a lower percolation threshold and a higher electrical conductivity compared with those with randomly dispersed SNP. However, when the concentration of the SNP reached a certain level (40 vol. %), the anisotropy of the effective material property became less noticeable than that of the lower concentration (20 vol. %) composites due to the change of the microstructure of the particles caused by the coalescence of the particles at a high concentration. This work may provide rational methods for the fabrication of aligned composites.

The electrical properties of vertical resistive switching random access memories (VRRAMs) were investigated to enhance their device performance by using a stochastic method based on the generation and the rupture probability of the conductive filaments (CFs) together with a tunneling model. The carrier transport mechanisms were dominantly attributed to the tunneling current between the CFs and the electrode. Carrier transport mechanisms of the high resistance state current were dominantly attributed to the direct tunneling current between the electrode and the CFs locating at nearest the electrode. The simulated forming voltages of the VRRAMs were in reasonable agreement with the experimental data. The low resistance/high resistance state current ratio of the VRRAMs was improved due to an increase in the distance between the CFs and the electrode of the VRRAMs with a barrier material after a reset operation. These results can help understanding electrical characteristics and optimal structures of the VRRAMs.

The cold spray process is a relatively new process using high velocity metallic particles for surface modifications. Metallic powder particles which are injected into a converging-diverging nozzle are accelerated to supersonic velocities. In this study effects of nozzle design such as diameter of nozzle throat and length of converging and diverging part of the nozzle on gas and particle velocities developed after the nozzle exit are investigated.