• Advances in nano research
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• v.16 no.6
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• pp.601-613
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• 2024

A new analytical buckling solution of a thermo-electro-magneto-elastic (TEME) cylindrical nano-shell made of BiTiO₃-CoFe₂O₄ materials is obtained based on Hamiltonian approach. The Winkler and Pasternak elastic foundations as well as thermo-electro-magneto-mechanical loadings are applied, and two different types of edge conditions are taken into the investigation. According to nonlocal strain gradient theory (NSGT) and surface elasticity theory in conjunction with the Kirchhoff-Love theory, governing equations of the nano-shell are acquired, and the buckling bifurcation condition is obtained by adopting the Navier's method. The detailed parameter study is conducted to investigate the effects of axial and circumferential wave numbers, scale parameters, elastic foundations, edge conditions and thermo-electro-magnetic loadings on the buckling behavior of the nano-shell. The proposed model can be applied in design and analysis of TEME nano components with multi-field coupled behavior, multiple edge conditions and scale effect.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.28.3-29
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• 2017

We present the results of very long baseline interferometry (VLBI) observations of gamma-ray bright blazar S5 0716+714 using the Korean VLBI Network (KVN) at the 22, 43, 86, and 129 GHz bands, which are part of the KVN key science program known as the Interferometric Monitoring of Gamma-ray Bright AGNs (iMOGABA). Multi-frequency VLBI observations were conducted in 29 sessions from January 16, 2013 to March 1, 2016. The source was detected and imaged in all available frequency bands. For all observed epochs, the source is compact on the milliarcsecond (mas) scale, yielding a compact VLBI core dominating the synchrotron emission on the mas scale. Based on the multi-wavelength data at 15 and 230 GHz, we found that the source shows multiple prominent enhancements of the flux density at the centimeter (cm) and millimeter (mm) wavelengths, with mm enhancements leading cm enhancements with a time lag of $18{\pm}5$ days. Turnover frequency is found to vary over our observations between 22 to 69GHz. Taking into account the synchrotron self-absorption model of the relativistic jet in S5 0716+714, we estimated the magnetic field strength in the mas emission region to be 0.4-66 mG during the observing period, finding that the magnetic field strength is strongly correlated with the turnover frequency and the relatively strong magnetic field (e.g., B > 40 mG) is correlated with flux enhancements at mm wavelengths (e.g., 86 GHz).

• Journal of Trauma and Injury
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• v.25 no.4
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• pp.122-131
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• 2012

Purpose: Diffuse axonal injury (DAI) is clinically defined as a coma of over six hours in a head trauma victim without a focal mass lesion. The emergency physician usually resuscitates and stabilizes a comatose head trauma victim in the emergency Department. After assessment and treatment, the prognosis is very important to both the victim and the physician. The prognosis for DAI is based on Glasgow Coma Scale (GCS) and other imaging data. We investigated the prognostic value of computed tomography (CT) and gradient-echo magnetic resonance imaging (GRI) for head trauma victims with DAI. Methods: Fifty-three(53) head trauma victims of DAI were enrolled in this study from 2007 to 2012. During the study period of six years, data on trauma victims were collected retrospectively. We analyzed the differences in the Glasgow Outcome Scale (GOS) result between the CT and the GRI modalities. Results: We classified the study group by using GOS. Between the good outcome subgroup (GOS scores of 4 and 5) and the poor outcome subgroup (GOS score of 1-3), there were no statistical difference in sex, age, initial vital signs and initial GCS score. The good outcome subgroup had non-hemorrhage on CT(52%), which was correlated with good outcome and a shorter awakening time, while a larger number and a deeper location of hemorrhagic lesions on in GRI were correlated with poor outcome in DAI. Conclusion: We conclude that the existence of hemorrhagic lesions on CT, and the number and location of those lesions on GRI had good prognostic value for head trauma victims with DAI.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.811-816
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• 2006

The single layered magnetic thin films with anisotropic magnetoresistance behavior have advantage on micro integration due to their low cost in manufacturing. Although the conventional MCo (M=Cu, Ag) amorphous ribbons using a rapid solidification process have showed appropriate for magnetic property for bulk devices, they are not appropriate for micro-scale devices due to their brittleness. We prepared the thermal evaporated 100 nm-thick $Cu_{1-x}Co_x\;and\;Ag_{1-x}Co_x(x=0.1{\sim}0.7)$ films on silicon wafers and investigated the magnetic property of the as-depo films such as magnetization and magnetoresistance ratio. We confirmed that the maximum MR ratio of 1.4 and 2.6% at the external field of 0.5 Tesla in $CuCo_{30},\;AgCo_{40}$ films, respectively. Our result implies that AMR may be slightly less than those of the conventional CuCo and AgCo ribbons due to surface scattering, but their AMR ratio be enough for micro-scale application with easy integration compatibility for the process without surface oxidation.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.540-549
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• 2017

Objective : To evaluate the diagnostic value of computed tomography-myelography (CTM) compared to that of magnetic resonance imaging (MRI) in patients with lumbar radiculopathy. Methods : The study included 91 patients presenting with radicular leg pain caused by herniated nucleus pulposus or lateral recess stenosis in the lumbar spine. The degree of nerve root compression on MRI and CTM was classified into four grades. The results of each imaging modality as assessed by two different observers were compared. Visual analog scale score for pain and electromyography result were the clinical parameters used to evaluate the relationships between clinical features and nerve root compression grades on both MRI and CTM. These relationships were quantified by calculating the receiver-operating characteristic curves, and the degree of relationship was compared between MRI and CTM. Results : McNemar's test revealed that the two diagnostic modalities did not show diagnostic concurrence (p<0.0001). Electromyography results did not correlate with grades on either MRI or CTM. The visual analog pain scale score results were correlated better with changes of the grades on CTM than those on MRI (p=0.0007). Conclusion : The present study demonstrates that CTM could better define the pathology of degenerative lumbar spine diseases with radiculopathy than MRI. CTM can be considered as a useful confirmative diagnostic tool when the exact cause of radicular pain in a patient with lumbar radiculopathy cannot be identified by using MRI. However, the invasiveness and potential complications of CTM are still considered to be pending questions to settle.

• Clinical Pain
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• v.19 no.1
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• pp.16-22
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• 2020

Objective: Recent studies have shown that repetitive peripheral magnetic stimulation (rPMS) reduces pain in various conditions. This pilot study aimed to investigate the effects of rPMS depending on the pain characteristics. Method: Adult patients aged 19~85 years evaluated at our institution between September 1, 2017 and February 28, 2018 for subacute to chronic musculoskeletal pain equivalent to a numeric rating scale of 3 or higher for at least one month were enrolled. Pain scores as determined using a numeric rating scale at baseline and at the end of treatment were set as the primary outcome. Additionally, we classified the pain into nociceptive, intermediate, or neuropathic pain using the PainDETECT questionnaire and compared the responsiveness to rPMS according to the type of pain. Results: The average pain scores significantly decreased after the 2-week rPMS treatment in all enrolled subjects (p<0.001). There was no statistically significant difference in pain reduction between groups divided by PainDETECT questionnaire. Conclusion: This study suggests that rPMS could safely relieve various types of pain.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.199-207
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• 2023

Since seeds can be directly used as food resources as well as for crop cultivation or preservation of genetic resources, it is essential to develop high-quality seed processing technology to increase agricultural productivity. Seed treatment means processing technologies of seeds through physical or chemical treatment processes from after harvesting seeds to before sowing of seeds to improve germination and growth rate, durability, and immunity, etc. Since chemical seed treatment technology using pesticides or plant growth regulators has problems of environmental pollution and human toxicity, it is desired to develop an alternative technology. As a physical seed treatment method, various technologies such as ionizing radiation, plasma, microwave, and magnetic field are being developed, and some of them are being used practically. In this paper, I will summarize the mechanism of seed priming and disinfection, and the advantages and disadvantages of application, focusing on these physical seed treatment methods. Low dose or moderate intensity ionizing radiation, microwave, low-temperature plasma, and magnetic field treatments often promoted seed germination and seedling growth. However, effective removal of direct seed pathogens at these treatment intensities appears to be difficult. And it has been shown that relatively high-dose electron beam treatment using low-energy electron beams kills microorganisms on the seed surface and hull layer while not damaging the inner tissue of the seed, and is also effectively used for seed treatment on a commercial scale. In order to put the physical seed treatment technology to practical use in Korea, it is necessary to develop an economical scale treatment device along with the development of individual treatment technology to each crop.

• The Journal of the Society of Stroke on Korean Medicine
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• v.18 no.1
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• pp.55-65
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• 2017

■ Objectives Atrial fibrillation is the most common cause of cardioembolic stroke. Of the 44 ischemic stroke patients with atrial fibrillation who were hospitalized in hospital of Korean Medicine from July 1, 2014 to June 30, 2017, we selected 39 patients who have had Magnetic Resonance Angiography. We divided them into Atrial Fibrillation group with no stenosis or less than 50% stenosis in the ipsilateral artery of the lesion and Artery to Artery Embolism group with more than 50% stenosis or occlusion in the ipsilateral artery of the lesion. ■ Methods Clinical characteristics, examination and evaluation tools were collected from the patient's electronic medical records. CHADS2, Initial National Institutes of Health Stroke Scale, 8-item Stroke Scale and Improved 8-item Stroke Scale Number were checked. ■ Results & Atrial Fibrillation group showed differences in age, brain lesion location, vascular lesion, Conclusion initial National Institutes of Health Stroke Scale, initial 8-item Stroke Scale and progress compared to Artery to Artery Embolism group.

• Korean Journal of Biological Psychiatry
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• v.18 no.4
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• pp.254-259
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• 2011

Objectives The aim of this study was to assess variations in caudate volume according to dopamin receptor D2/ankyin repeat and kinase domain containing 1 (DRD2/ANKK1) Taq 1a polymorphisms in young healthy adults and to evaluate the relationship between caudate volumes and psychiatric symptoms as measured by the Brief Psychiatric Rating Scale. Methods Genetic information regarding DRD2/ANKK1 Taq 1a and T1-weighted brain magnetic resonance images were acquired from 30 young healthy adults. Automatic segmentation of caudate was performed using the FreeSurfer program. Results Individuals with A2 homozygotes of DRD2/ANKK1 Taq 1a polymorphisms (n = 10) had greater right caudate volumes compared to those with A1 allele (s)(18.4% greater ; p = 0.019). Right caudate volumes were negatively associated with total scores of the Brief Psychiatric Rating Scale (${\beta}$=-0.50 ; p = 0.016). Conclusions Our findings suggest the possibility that DRD2/ANKK1 Taq 1a polymorphisms may underlie the psychiatric symptoms by influencing the structure of the right caudate.

• The Journal of Korean Physical Therapy
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• v.23 no.1
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• pp.53-58
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• 2011

Purpose: The purpose of this study was to determine the effect of direct functional magnetic stimulation (FMS) of affected spinal cord on motor recovery following spinal cord injury in rats. Methods: After a contusion injury at the spinal level T9 using an NYU Impactor, functional magnetic stimulation was delivered by a magnetic stimulator through a round prototype coil (7 cm in diameter). Stimulation parameters were set as follows: repetition rate = 50 Hz (stimulus intensity 100% = 0.18 T), stimulation time = 20 min. Functional magnetic stimulation was administered twice a day, 5 days per week for 8 weeks starting 4 days after spinal cord injury. Functional magnetic stimulationwas delivered directly to the affected spinal cord. Outcomes of locomotor performance were assessed by the Basso Beattie Bresnahan (BBB) locomotor rating scale and by an inclined plane test weekly for 8 weeks. Results: In the BBB test, hindlimb motor function in the Functional magnetic stimulation group improved significantly more compared to the control group at 3, 4, 6, 7, and 8 weeks (p<0.05). In the inclined plane test, the angle of the plane in the functional magnetic stimulation group increased significantly more compared to the control group at 4, 5, 7, and 8 weeks (p<0.05). Conclusion: Our results demonstrate that direct Functional magnetic stimulation of the lesional site may have beneficial effects on motor improvement after spinal cord injury.