마비형 뇌성마비환자의 뇌파 및 임상양상

윤여훈,송홍기,김형철,이병철,이숙자 대한신경과학회 1996 대한신경과학회지 Vol.14 No.1

저강도 초음파 및 레이저를 이용한 장관골 불유합의 치료

전인호,오창욱,김성중,경희수,박일형,박병철,인주철,여준영 대한골절학회 2003 대한골절학회지 Vol.16 No.2

목 적: 저강도 초음파는 인체 및 동물 실험에서 골조직에 낮은 미세한 물리적 압력을 가하여 골절의 치유에 유리한 영향을 주고, 레이저 (LASER)는 심부 조직에 혈류를 증가시키고, 세포 내 잠재된 에너지를 증가시키는 것으로 알려져 있다. 이에 저자들은 임상적으로 확진된 장관골 붕류합의 치료에 있어 펄스형 저강도 초음파와 레이저를 적용하고 그 효용성을 알아보고자 하였다. 대상 및 방법: 초음파/레이저의 치료 효과를 비교하기 위하여 장관골 불유합으로 확진된 16예 중 8예는 연구군으로 골이식술 후 저강도 초음파와 레이저 치료를 추가하였고 대조군 8예에 대해선 일반적인 골이식술만 시행하여 조사하였다. 남자가 11예, 여자가 5예, 평균 연령은 41.7세 (19~62세)였고, 불유합 부위는 대퇴골이 10예, 경골이 6예였다. 첫 수상으로 인한 골절 후 초음파/레이저 치료까지 시간(골절 연력)은 평균 502일이었다. 결 과: 8예의 연구군에서는 완전 골유합이 6예에서 이루어졌으며 유합까지의 시간은 평균 141일 (101~202일)로 나타난 반면, 8례ㅢ 대조군에서는 5예에서 골유합이 이루어졌고, 유합까지의 시간은 평균 240일 (183~283일)이었다. 결 론: 저강도 초음파/레이져 골절 치료기가 반복된 수술로 인한 난치성 장관골 불유합의 치료에 있어 골이식술과 함께 사용될 경우 긍정적인 효과가 있었고, 특히 최초 가골 형성에 있어 대조군에 비해 그 시간을 줄일 수 있었따. Purpose: Low-intensity, pulsed ultrasound (LIPUS) has demonstrated a stimulation and acceleration of the normal fracture-repair process in cellular bases as well in animal and human models. In this study, the adjunctive effect of LIPUS and LASER was investigated in established nonunion of the long bones. Materials and Methods: Study group consisted of eight patients to whom conventional bone graft and adjunctive LIPUS and LASER was applied. On the other hands, eight patients in the control group underwent bone graft only. Eleven men and five women were included in this study and the average age of the patients was 41.7 years (range, 19~62 years). Six of the tibias and ten of the femurs met the criteria for established nonunion. The average fracture age, the post-fracture period before the start of LIPUS/LASER treatment, was 502 days. Results: Seven of the ten nonunions who were treated by LIPUS and LASER healed completely in an average treatment time of 141 days (range, 101~202 days) and otherwise, in control group, five of the eight nonunions healed completely, in 240 days (range 183~283 days). Conclusion: This clinical study showed a positive effect of LIPUS and LASER on the rate of osseous repair, especially accelerated time to initial callus cortical bridging compared to that of conventional treatment.

High-Throughput Screening to Investigate the Relationship between the Selectivity and Working Capacity of Porous Materials for Propylene/Propane Adsorptive Separation

Yeo, Byung Chul,Kim, Donghun,Kim, Hyungjun,Han, Sang Soo American Chemical Society 2016 The Journal of Physical Chemistry Part C Vol.120 No.42

<P>An efficient propylene/propane separation is a very critical process for saving the cost of energy in the petrochemical industry. For separation based on the pressure-swing adsorption process, we have screened similar to 1 million crystal structures in the Cambridge Structural Database and Inorganic Crystal Structural Database with descriptors such as the surface area of N-2, accessible surface area of propane, and pore-limiting diameter. Next, grand canonical Monte Carlo simulations have been performed to investigate the selectivities and working capacities of propylene/propane under experimental process conditions. Our simulations reveal that the selectivity and the working capacity have a trade-off relationship. To increase the working capacity of propylene, porous materials with high largest cavity diameters (LCDs) and low propylene binding energies (Q(st)) should be considered; conversely, for a high selectivity, porous materials with low LCDs and high propylene Q(st) should be-considered, which leads to a trade-off between the selectivity and the working capacity. In addition, for the design of novel porous materials with a high selectivity, we propose a porous material that includes elements with a high crossover distance in their Lennard-Jones potentials for propylene/propane such as In, Te, Al, and I, along with the low LCD stipulation.</P>

Artificial Intelligence-Aided Identification of Crystallographic Surfaces from Electron Microscopy Images

Byung Chul Yeo 한국표면공학회 2023 한국표면공학회 학술발표회 초록집 Vol.2023 No.11-1

Atomistic Simulation Protocol for Improved Design of Si–O–C Hybrid Nanostructures as Li-Ion Battery Anodes: ReaxFF Reactive Force Field

Yeo, Byung Chul,Jung, Hyun,Lee, Hong Woo,Yun, Kang-Seop,Kim, Hyungjun,Lee, Kwang-Ryeol,Han, Sang Soo American Chemical Society 2017 The Journal of Physical Chemistry Part C Vol.121 No.42

<P>Recently, silicon oxygen carbon hybrid nanostructures have received great attention as a promising anode material for Li-ion batteries, for which their diverse structures can be synthesized. Here,. using molecular dynamics (MD) simulations with a reactive force field (ReaxFF), we studied the atomistic lithiation behaviors of sp(2) carbon coated Si and SiOx nanostructures, such as nanowires (NWs) and nanoparticles (NPs), in which various kinds and sizes of carbonaceous coating layers were explored. The introduction of an sp(2) carbonaceous coating layer to Si-based anodes makes Li diffusion more facile, which leads to improved battery performances such as faster charge/discharge rates. Moreover, the carbonaceous coating layer can also provide a buffer effect to volume changes during lithiation along with the well-known functions of preventing the loss of electrical continuity and increasing electrical conductivity of Si-based anodes. However, a thick carbonaceous coating layer can strongly suppress the volume expansion behavior of Si-based nanostructures and thus prevent Li penetration into the nanostructures, leading to a very low Li capacity. According to our ReaxFF-MD simulations, the critical size of the carbonaceous coating layer that can act as a buffer layer is approximately C/Si = 2.4, which is the circumference ratio of the carbonaceous coating layer over the Si NWs. For a coating layer that has a higher ratio, Li cannot penetrate into the Si NWs; instead, they exist only on and in the sp(2) coating layers including in the spaces between two graphene layers. Moreover, the shape of the Si nanostructures (e.g., NW and NP) does little to affect the anode properties, such as Li capacity and volume change, although Si NP confined in a carbon nanotube shows anisotropic volume expansion behavior during lithiation. We expect that the ReaxFF will provide a useful protocol for designing Si-O-C hybrid anodes to obtain better performing Li-ion batteries.</P>

ReaxFF-MD 시뮬레이션을 이용한 Lithium 이차전지용 Graphene 코팅된 Silicon 나노소재 개발 연구

여병철(Byung Chul Yeo),김형준(Hyungjun Kim),한상수(Sang Soo Han) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

Contribution of the Pedunculopontine Nucleus on Walking in Stroke Patients

Yeo, Sang Seok,Ahn, Sang Ho,Choi, Byung Yeon,Chang, Chul Hoon,Lee, Jun,Jang, Sung Ho S. Karger AG 2011 European neurology Vol.65 No.6

<P>Abstract</P><P><I>Objectives:</I> We attempted to investigate changes of the pedunculopontine nucleus (PPN) according to walking ability in chronic stroke patients, using diffusion tensor imaging (DTI). <I>Methods:</I> 55 consecutive chronic stroke patients who were not able to walk due to injury of the corticospinal tract (CST) at stroke onset and 22 age-matched normal control subjects were recruited. We measured the values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the PPN and assessed the walking ability of each patient. <I>Results:</I> In patients who were able to walk independently, the FA value of the PPN in the affected hemisphere was increased without change of the ADC value (p < 0.05). Increase of the FA value was positively correlated with the degree of walking ability (p < 0.05). In contrast, the ADC value was increased in the affected hemisphere of patients who could not walk, without change of the FA value (p < 0.05). This increase of the ADC value was negatively correlated with the degree of walking ability (p < 0.05). <I>Conclusion:</I> We found that the neuronal activity of the PPN in the affected hemisphere was increased in stroke patients who were able to walk independently. Therefore, we think that the PPN in the affected hemisphere contributed to walking ability in stroke patients with CST injury.</P><P>Copyright © 2011 S. Karger AG, Basel</P>

Cost-effectiveness Analysis for the Screening of Immigrants with Latent Tuberculosis in South Korea

( Yeo Wool Lee ),( Jang Mi Yang ),( Hae-young Kim ),( Seung Chul Lee ),( Byung Chul Chun ),( In-hwan Oh ),( Seung Heon Lee ) 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.-

Background Tuberculosis (TB) incidence in foreign-born immigrants are increasing in South Korea. Therefore, immigrants screening for latent tuberculosis infection (LTBI) control is important to prevent reactivation of TB in national TB control program (NTP). However, the evidence of national guidance for immigrant screening based on cost-effectiveness is lacking. We aimed to define which groups should be screened for LTBI based on cost-effectiveness. Methods We used interferon-γ release-assay (IGRA) Results of immigrants from passive case finding surveillance for VISA renewal in the South Korea (from 2018 to 2019). Among the recent immigrants below 65 years old with normal chest X ray, without previous TB treatment history, we assessed factors associated with latent infection by use of logistic regression and calculated the cost-effectiveness of screening at different levels of tuberculosis incidence in immigrants’ countries of origin using a decision analysis model. Results Results for IGRA-based screening were positive in 1,559 of 6,116 immigrants (25.5%), negative in 4,557 (74.5%). Among 6,164 immigrants, positive Results were independently associated with increases in tuberculosis incidence in immigrants’ countries of origin (p<0.05), male sex (OR 1.209, CI: 1.063-1.375, p=0.006), and age (p<0.0001). Among 16~35 years old immigrants, the most cost-effective strategies were to screen individuals from countries with a tuberculosis incidence of more than 250 cases per 100,000. On this cut-off level, incremental cases of active TB prevented and incremental costs over 5 years were 10.8 cases, and 65,252,725 won ($54,377), respectively and incremental cost-effectiveness ratio [ICER] was 6,025,823 won ($5,022) per prevented case of tuberculosis, compared with no screening strategy. Conclusions In South Korea, screening for latent TB infection in immigrants of 16~35 years old can be implemented most cost-effectively for individuals from countries at a TB incidence of more than 250 cases per 100,000.

Periventricular White Matter Injury by Primary Intraventricular Hemorrhage: A Diffusion Tensor Imaging Study

Yeo, Sang Seok,Choi, Byung Yeon,Chang, Chul Hoon,Jung, Young Jin,Ahn, Sang Ho,Son, Su Min,Byun, Woo Mok,Jang, Sung Ho S. Karger AG 2011 European neurology Vol.66 No.4

<P>Abstract</P><P><I>Objectives:</I> Intraventricular hemorrhage (IVH) in adult stroke patients is known to be an independent risk factor for poor functional outcome. Using diffusion tensor imaging (DTI), we attempted to investigate the effect of IVH on the white matter. <I>Methods:</I> We recruited 10 consecutive patients with IVH and 18 age- and sex-matched control subjects. Using a 1.5-T Philips Gyroscan Intera system, DTI data was acquired at an average of 84 days (range: 38–149) after IVH onset. We measured fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values at the fornix, corpus callosum (CC), corona radiata (CR), and posterior limb of the internal capsule (PL). In addition, integrity and fiber number were measured for the fornix. <I>Results:</I> DTI revealed disruption of the fornix in all patients. FA values showed a decrease in the fornix, CC, and CR; in contrast, the ADC value showed an increase in the CC, without changes in the fornix or CR. Fiber number of the fornix also decreased. However, no change was observed in the PL. <I>Conclusions:</I> We found periventricular white matter (fornix, CC, and CR) injury following IVH. We think that this result would be helpful in the establishment of management strategies for patients with IVH.</P><P>Copyright © 2011 S. Karger AG, Basel</P>

Actinomyces-like organisms in cervical smears: the association with intrauterine device and pelvic inflammatory diseases

( Yeo Joo Kim ),( Jina Youm ),( Jee Hyun Kim ),( Byung Chul Jee ) 대한산부인과학회 2014 Obstetrics & Gynecology Science Vol.57 No.5

Objective To investigate the incidence of actinomyces-like organisms in routine cervical smears of Korean women and to evaluate its association with the development of pelvic inflammatory disease (PID) in these women. Methods The results of cervical smears between 2011 and 2012 at a single university hospital were searched. If positive for actinomyces-like organisms, the medical record of the patient was searched and development of PID was followed. If the data were not available in the medical record, the patient was contacted by telephone. Results The incidence of actinomyces-like organisms in cervical smears was 0.26% (52/20,390). Forty-two women (80.8%) were intrauterine device (IUD) users: the copper-IUD in 25 women and the levonorgestrel-releasing intrauterine system in 13 women (type unknown in 4 women). The majority (71.4%, 30/42) of the IUD users maintained the IUD. Prophylactic antibiotics were prescribed to 12 women. Two continuous IUD users were later diagnosed with PID, but these cases were not pelvic actinomycosis. Conclusion It would be a reasonable option to choose the expectant management for asymptomatic women who incidentally showed actinomyces-like organisms in their cervical smear.