Sooseok Choi

Inability to control anger or aggression after stroke.

Abstract—Using the 10-item Spielberger Trait Anger Scale, the authors interviewed 145 patients with stroke regarding inability to control anger or aggression (ICAA). Poststroke depression and emotional incontinence were also assessed. ICAA was present in 47 patients (32%) and was closely related to motor dysfunction, dysarthria, emotional incontinence, and lesions affecting frontal–lenticulocapsular–pontine base areas. ICAA seems to be one of the major behavioral symptoms in patients with stroke.

Poststroke depression and emotional incontinence Factors related to acute and subacute stages

Objectives: To investigate the characteristics and prevalence of poststroke depression (PSD) and poststroke emotional incontinence (PSEI) and the factors related to these conditions at admission and 3 months after stroke. Methods: We evaluated 508 consecutive patients with acute ischemic stroke for PSD and PSEI at admission and 3 months later. PSD was evaluated using the Beck Depression Inventory, and PSEI was evaluated using Kims criteria. Blood samples were collected and genotyped for the promoter region of the serotonin transporter protein (5-HTTLPR) and the number of tandem repeats within intron 2 (STin2 VNTR). Perceived social support (the ENRICHD Social Support Inventory) was also measured. Results: PSD and PSEI were present in 13.7% and 9.4% of patients, respectively, at admission and in 17.7% and 11.7%, respectively, at 3 months after stroke. Multivariate analyses showed that PSD at admission was associated with the NIH Stroke Scale score at admission (p < 0.001), whereas PSD at 3 months was associated with the presence of microbleeds (p < 0.01) and perceived low social support (p < 0.001). In contrast, only lesion location (p = 0.022) was associated with PSEI at admission, whereas modified Rankin Scale score (p = 0.019), STin2 VNTR (p = 0.040), and low social support (p = 0.042) were related to PSEI 3 months after stroke. Conclusions: Diverse factors such as neurologic dysfunction, lesion location, microbleeds, genetic traits, and social support are differently related to acute and subacute emotional disturbances. Strategies to prevent or manage these problems should consider these differences.

Simultaneous treatment of NO and SO2 with aqueous NaClO2 solution in a wet scrubber combined with a plasma electrostatic precipitator.

NO and SO2 gases that are generally produced in thermal power plants and incinerators were simultaneously removed by using a wet scrubber combined with a plasma electrostatic precipitator. The wet scrubber was used for the absorption and oxidation of NO and SO2, and non-thermal plasma was employed for the electrostatic precipitation of aerosol particles. NO and SO2 gases were absorbed and oxidized by aerosol particles of NaClO2 solution in the wet scrubber. NO and SO2 reacted with the generated NaClO2 aerosol particles, NO2 gas, and aqueous ions such as NO2(-), NO3(-), HSO3(-), and SO4(2-). The aerosol particles were negatively charged and collected on the surface of grounded anode in the plasma electrostatic precipitator. The NO and SO2 removal efficiencies of the proposed system were 94.4% and 100% for gas concentrations of 500 mg/m(3) and a total gas flow rate of 60 Nm(3)/h, when the molar flow rate of NaClO2 and the gas-liquid contact time were /min and 1.25 s, respectively. The total amount and number of aerosol particles in the exhaust gas were reduced to 7.553 μg/m(3) and 210/cm(3) at the maximum plasma input power of 68.8 W, which are similar to the values for clean air.

Enthalpy probe measurements and three-dimensional modelling on air plasma jets generated by a non-transferred plasma torch with hollow electrodes

Thermal flow characteristics of air plasma jets generated by a non-transferred plasma torch with hollow electrodes are experimentally and numerically investigated in order to provide more reliable scientific and technical information, which has been insufficient for their practical applications to material and environmental industries. In this work, a thermal plasma torch of hollow electrode type is first designed and fabricated, and similarity criteria for predicting operational conditions for the scale-up to high-power torches are derived from the arc voltage characteristics measured with various operating and geometry conditions of the torch. The thermal flow characteristics of air plasma jets ejected from the torch are measured by enthalpy probe diagnostics and turn out to have relatively low temperatures of around 3000?7000?K, but show features of other unique properties, such as high energy flux, broad high temperature region and long plasma jet with moderate axial velocity, which are promising for their applications to material syntheses and hazardous waste treatments. Such high enthalpy at a relatively low temperature of air thermal plasma compared with the argon one is due to the high thermal energy residing in the vibrational and rotational states and oxygen dissociation, besides the translational states in monatomic gases such as argon. It is expected that this high specific enthalpy of the air plasma will enable material and environmental industries to treat a large amount of precursors and waste materials effectively at a lower temperature for a longer residence time by the low plasma velocity. It is also found from the measurements that the turbulence intensity influenced by the size of the electrode diameter has a significant effect on the axial and radial profiles of plasma jet properties and that a longer plasma jet is more readily achievable with a larger electrode diameter reducing the turbulence intensity in the external region of the torch. In the numerical studies based on magnetohydrodynamics (MHD) theory, a precise three-dimensional transient numerical model for the internal arc discharge plasma of the torch has been developed along with a practical two-dimensional stationary one for the external thermal plasma jet by considering highly localized distributions of arc roots with circumferential non-uniformity on the electrode wall surfaces, so that more reliable and realistic descriptions on the arc thermal plasma properties become feasible both inside and outside the torch. The numerical calculation results are compared with the experimental data obtained from the probe measurements and found to be in good agreement with them.

Comparative study of two- and three-dimensional modeling on arc discharge phenomena inside a thermal plasma torch with hollow electrodes

A comparative study between two- and three-dimensional (2D and 3D) modeling is carried out on arc discharge phenomena inside a thermal plasma torch with hollow electrodes, in order to evaluate the effects of arc root configuration characterized by either 2D annular or 3D highly localized attachment on the electrode surface. For this purpose, a more precise 3D transient model has been developed by taking account of 3D arc current distribution and arc root rotation. The 3D simulation results apparently reveal that the 3D arc root attachment brings about the inherent 3D and turbulence nature of plasma fields inside the torch. It is also found that the constricted arc column near the vortex chamber plays an important role in heating and acceleration of injected arc gases by concentrating arc currents on the axis of the hollow electrodes. The inherent 3D nature of arc discharge is well preserved inside the cathode region, while these 3D features slowly diminish behind the vortex chamber where the turbulent flo...

Musculoskeletal and central pain at 1 year post-stroke: associated factors and impact on quality of life

Pain is common in post‐stroke patients and has been shown to be associated with depression, fatigue, and decreased quality of life (QOL). However, studies examining different types of post‐stroke pain are scarce. We investigated differences in the related factors and their QOL impacts between musculoskeletal pain (MSP) and central post‐stroke pain (CPSP).

Investigation of the relationship between arc-anode attachment mode and anode temperature for nickel nanoparticle production by a DC arc discharge

Multiple and constricted arc-anode attachment modes were observed in helium arc discharge to prepare nickel nanoparticles. The electron overheating instability resulted in the formation of multiple attachment modes. The effects of hydrogen concentration and shield gas flow rate on the characteristics of nickel nanoparticles were investigated. The evaporation rate of anode material contributed to forming different arc-anode attachments. The surface temperature of the electrode was measured during the arc discharge by two-color pyrometry combined with a high-speed camera which employs appropriate band-pass filters. The relationship between the arc-anode attachment mode and the temperature behavior of the anode surface was investigated by using two synchronized high-speed cameras. The waveform of anode jet area variation with time follows that of the highest temperature variation of anode surface with time. The fluctuation of the highest anode temperature increased when the arc anode attachment changed from multiple into constricted mode. The highest temperature fluctuation and stability of the arc contributed to nanoparticle size distribution. Nickel nanoparticles with large productivity and narrow size distribution were obtained when shield gas was employed by controlling the residence time of nanoparticle growth. The formation mechanism of different arc-anode attachment modes was explained.

Investigation of electrode erosion mechanism of multi-phase AC arc by high-speed video camera

A multi-phase AC arc has been applied to the glass melting technology. However, the electrode erosion is one of the most considerable issues to be solved. In order to investigate the erosion mechanism of the multi-phase AC arc, the combination of the high-speed video camera and the band-pass filters was introduced to measure the electrode temperature. Results indicated the tip temperature of the electrode surface in the 12-phase arc was lower than that in the 2-phase arc, while erosion rate in 12-phase arc was higher than that in the 2-phase arc. Furthermore, the dynamic behaviour of the vapours in the arc was investigated by using the same high-speed camera system. The tungsten electrode mainly evaporates at the anodic period during AC cycle. The oxygen concentration in the arc increases with larger number of the phases, resulting in the higher erosion rate in the 12-phase arc.

In-flight particle measurement of alkali-free glass raw materials in 12-phase AC Arc plasma

In-flight particle measurements of the surface temperature and velocity are important for understanding of melting behavior of glass particles during in-flight melting by multi-phase AC arc plasma. However, the use of optical pyrometry for particle surface temperature has inevitable uncertainties due to non-thermal emissions signals from the plasma plume. This work presents spectroscopic measurements of the non-thermal signals which were found to be caused mainly by the plasma emissions scattered by the particles and the radiation emitted by vapor. After that, the accuracy of thermal radiation measurement was estimated and surface temperature of in-flight glass particle was corrected.

Synthesis of AlB12 and YB66 Nanoparticles by RF Thermal Plasmas

Boron-rich compounds of AlB12 and YB66 nanoparticles were synthesized in radio frequency (RF) thermal plasmas. Yttrium tetraboride or aluminium powders with 10 μm in diameter and boron powder with 45 μm in diameter were evaporated in the high temperature region of the thermal plasma, and then metal boride nanoparticles were formed in the tail region of the plasma with rapid quenching. Boron-rich compounds were identified by X-ray diffractometry in the product. Polyhedral shaped nanoparticles about 20 nm in size were measured in Al-B system by transmission electron microscopy, while YB66 particles about 50 nm in size were cubic in morphology. The composition of raw powder and the input power of RF thermal plasma were controlled to enhance the content of boron-rich metal borides in as-prepared nanoparticles. Since boron has very high melting point and evaporation temperature, high boron content in the raw powder and high input plasma power were preferable to synthesize AlB12 and YB66 nanoparticles.