• IEIE Transactions on Smart Processing and Computing
• /
• 제3권1호
• /
• pp.28-34
• /
• 2014

Recently, ultrasound therapy has become a new and effective treatment for many brain diseases. Therefore, skull-mimicking phantoms have been developed to simulate the skull and brain tissue of a human and allow further research into ultrasound therapy. In this study, the suitability of various skull-mimicking materials(HDPE, POM C, Acrylic) for studies of brain-tumor treatments was evaluated using focused ultrasound. The acoustic properties of three synthetic resins were measured. The skull-mimicking materials were then combined with an egg white phantom to observe the differences in the ultrasound beam distortion according to the type of material. High-intensity polyethylene was found to be suitable as a skull-mimicking phantom because it had acoustic properties and a denatured-area shape that was close to those of the skull,. In this study, a skull-mimicking phantom with a multi-layer structure was produced after evaluating several skull-mimicking materials. This made it possible to predict the denaturation in a skull in relation to focused ultrasound. The development of a therapeutic protocol for a range of brain diseases will be useful in the future.

• Tuberculosis and Respiratory Diseases
• /
• 제59권1호
• /
• pp.109-113
• /
• 2005

저자들은 중증 폐렴으로 인한 ARDS양상으로 내원한 임신 3개월의 속립성 결핵 환자를 경기관지 폐생검과 방사선 소견 및 임상양상을 종합적으로 고려하여 속립성 결핵에 의한 ARDS로 확진할 수 있었던 1예를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• 대한물리의학회지
• /
• 제10권1호
• /
• pp.91-97
• /
• 2015

PURPOSE: In this study investigated the thermal effect in tissue mimicking phantom by the material of the ultrasonic transducer in low intensity sonication. METHODS: The material of the ultrasonic transducer was made of ceramic, stainless steel, aluminum. Korea Testing Laboratory was measured of the three kinds of materials the total output of the ultrasonic transducer. Each material was measured core temperature and the actual output depending on the type of transducer. Agarose tissue mimicking phantom and silicone tissue mimicking phantom was made. Transducers made of three kinds of materials were emitted in the phantom. It is shown as a graph about time and temperature and the surface temperature rising speed and deep temperature rise rate was investigated. RESULTS: Ceramic transducers were highest output. Higher than the stainless steel transducer, aluminum had the lowest total output. Deep temperature was the highest in the ceramic transducer, and the surface temperature was the highest in the stainless steel transducer. Thermal images of ceramic transducer showed that a valid output is formed deeper wider than the metal. CONCLUSION: Ceramic transducer is confirmed the excellence than the metal transducer in deep thermal effect and the actual output of the ultrasound.

• 제어로봇시스템학회논문지
• /
• 제18권2호
• /
• pp.76-80
• /
• 2012

This paper demonstrates how to implement inherent pitching stability in an insect-mimicking flapping-wing system for vertical takeoff. Design and fabrication of the insect-mimicking flapping-wing system is briefly described focusing on the recent modification. Force produced by the flapping-wing systems is estimated using the UBET (Unsteady Blade Element Theory) developed in the previous work. The estimation shows that the wing twist placed in the modified system can improve thrust production for about 10 %. The estimated thrust is compared with the measured thrust, which proves that the UBET provides fairly good estimations for the thrust produced by the flapping-wing systems. The vertical takeoff test shows that inherent pitching stability can be implemented in an insect-mimicking flapping-wing system by aligning the aerodynamic force center and center of gravity.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 2017년도 춘계공동학술대회
• /
• pp.110-110
• /
• 2017

Biological systems offer unique principles for the design and fabrication of engineering platforms (i.e., popularly known as "Biomimetics") for various applications in many fields. For example, the lotus leaves exhibit unique surfaces consisting of evenly distributed micro and nanostructures. These unique surfaces of lotus leaves have the ability of superhydrophobic property to avoid getting wet by the surrounding water (i.e., Lotus effect). Inspired by the surface topographies of lotus leaves, the artificial superhydrophobic surfaces were developed using various micro- and nanoengineering. Here, we propose new platforms that can control hydrophilic and hydrophobic property of surfaces by mimicking micro- and nanosurfaces of various natural leaves such as common camellia, hosta plantaginea, and lotus. Using capillary force lithography technology and polymers in combination with biomimetic design principle, the unique micro- and nanostructures mimicking natural surfaces of common camellia, hosta plantaginea, and lotus were designed and fabricated. We also demonstrated that the replicated polymeric surfaces had different hydrophilic and hydrophobic properties according to the mimicking the natural leaf surfaces, which could be used as a simple, but powerful methodology for design and fabrication of controlled hydrophilic and hydrophobic platforms for various applications in the field of agriculture and biological engineering.

• Journal of Korean Neurosurgical Society
• /
• 제57권1호
• /
• pp.50-53
• /
• 2015

Usually fungal infections caused by opportunistic and pathogenic fungi had been an important cause of morbidity and mortality among immunocompromised patients. However clinical data and investigations for immunocompetent pathogenic fungal infections had been rare and neglected into clinical studies. Especially Cryptococcal brainstem abscess cases mimicking brain tumors were also much more rare. So we report this unusual case. This 47-year-old man presented with a history of progressively worsening headache and nausea for 1 month and several days of vomituritions before admission. Neurological and laboratory examinations performed demonstrated no abnormal findings. Previously he was healthy and did not have any significant medical illnesses. A CT and MRI scan revealed enhancing $1.8{\times}1.7{\times}2.0$ cm mass lesion in the left pons having central necrosis and peripheral edema compressing the fourth ventricle. And also positron emission tomogram scan demonstrated a hot uptake of fluoro-deoxy-glucose on the brainstem lesion without any evidences of systemic metastasis. Gross total mass resection was achieved with lateral suboccipital approach with neuronavigation system. Postoperatively he recovered without any neurological deficits. Pathologic report confirmed Cryptococcus neoformans and he was successively treated with antifungal medications. This is a previously unreported rare case of brainstem Cryptococcal abscess mimicking brain tumors in immunocompetent host without having any apparent typical meningeal symptoms and signs with resultant good neurosurgical recovery.

• Journal of Microbiology and Biotechnology
• /
• 제22권9호
• /
• pp.1279-1287
• /
• 2012

We established an efficient transformation method for thermophile Geobacillus kaustophilus HTA426 using conjugative transfer from Escherichia coli of host-mimicking plasmids that imitate DNA methylation of strain HTA426 to circumvent its DNA restriction barriers. Two conjugative plasmids, pSTE33T and pUCG18T, capable of shuttling between E. coli and Geobacillus spp., were constructed. The plasmids were first introduced into E. coli BR408, which expressed one inherent DNA methylase gene (dam) and two heterologous methylase genes from strain HTA426 (GK1380-GK1381 and GK0343-GK0344). The plasmids were then directly transferred from E. coli cells to strain HTA426 by conjugative transfer using pUB307 or pRK2013 as a helper plasmid. pUCG18T was introduced very efficiently (transfer efficiency, $10^{-5}-10^{-3}\;recipient^{-1}$). pSTE33T showed lower efficiency ($10^{-7}-10^{-6}\;recipient^{-1}$) but had a high copy number and high segregational stability. Methylase genes in the donor substantially affected the transfer efficiency, demonstrating that the host-mimicking strategy contributes to efficient transformation. The transformation method, along with the two distinguishing plasmids, increases the potential of G. kaustophilus HTA426 as a thermophilic host to be used in various applications and as a model for biological studies of this genus. Our results also demonstrate that conjugative transfer is a promising approach for introducing exogenous DNA into thermophiles.

• 대한방사선기술학회지:방사선기술과학
• /
• 제39권2호
• /
• pp.157-161
• /
• 2016

본 연구에서는 자체 제작한 3종의 초음파 TM 팬텀의 음향학적 특성 및 온도 민감도를 측정하였으며, 초음파 영상학적 특성을 관찰, 평가하였다. TM 팬텀은 폴리우레탄을 주재료로 국제전기표준회의(International Electronical Committee, IEC) 기준안에 따라 제작하였으며 외부 온도 변화 따른 초음파 영상학적 특성은 $22^{\circ}C$ 이하에서 온도감소에 따라 휘도 및 영상투과심도가 비례하여 감소하는 것이 확인되었다. 본 연구를 통하여 산란재 특성이 상이한 TM 팬텀을 제작하는 기초자료를 제공하였으며, TM 팬텀의 사용 온도는 $22^{\circ}C$ 이상에서 사용하는 것이 적합한 것으로 판단되었다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권9호
• /
• pp.5409-5413
• /
• 2013

Background: To assess the accuracy of ultrasound in differentiating endometrioma from ovarian cancer and to describe pattern recognition for atypical endometriomas mimicking ovarian cancers. Materials and Methods: Patients scheduled for elective surgery for adnexal masses were sonographically evaluated for endometrioma within 24 hours of surgery. All examinations were performed by the same experienced sonographer, who had no any information of the patients, to differentiate between endometriomas and non-endometriomas using a simple rule (classic ground-glass appearance) and subjective impression (pattern recognition). The final diagnosis as a gold standard relied on either pathological or post-operative findings. Results: Of 638 patients available for analysis, 146 were proven to be endometriomas. Of them, the simple rule and subjective impression could sonographically detect endometriomas with sensitivities of 64.4% (94/146) and 89.7% (131/146), respectively. Of 52 endometriomas with false negative tests by the simple rule, 13 were predicted as benign masses and 39 were mistaken for malignancy. Solid masses and papillary projections were the most common forms mimicking ovarian cancer, consisting of 38.5% of the missed diagnoses. However, with pattern recognition (subjective impression), 32 from 39 cases mimicking ovarian cancer were correctly predicted for endometriomas. All endometriomas subjectively predicted for ovarian malignancy were associated with high vascularization in the solid masses. Conclusions: Pattern recognition of endometriomas by subjective assessment had a higher sensitivity than the simple rule in characterization of endometriomas. Most endometriomas mimicking ovarian malignancy could be correctly predicted by subjective impression based on familiarity of pattern recognition.

• 경영과정보연구
• /
• 제32권3호
• /
• pp.83-105
• /
• 2013

기관투자자들의 군집행동에 대해서는 다양한 연구들이 이루어져 왔으나 기관투자자를 구성하는 여러 투자자들 간의 거래행태의 관계에 대하여는 그 연구가 부족한 상태이다. 따라서 본 연구에서는 2009년 한국거래소의 일중거래자료를 바탕으로 기관투자자를 구성하는 은행, 보험, 증권, 연기금 등과 같은 세부 투자자 유형의 거래행태에 있어서 어떠한 관계가 있는지 살펴보았다. 그 결과 외국인, 개인, 그리고 증권 투자자의 경우 대체로 연기금을 비롯한 나머지 투자자 유형과는 주로 반대거래를 하고 있는 것으로 나타났으며 연기금, 보험, 자산운용, 사모펀드, 기타법인 및 국가, 은행 등은 서로간 교차추종을 하고 있어 군집행동의 증거가 관찰되었다. 특히 연기금과 보험은 오랜 기간 서로 교차추종거래를 하고 있는 것으로 조사되었다. 따라서 2009년의 경우 증권을 제외한 기관투자자들은 짧은 추종시차에서 군집행동을, 보험과 자산운용, 연기금 및 기타법인의 경우 군집행동과 자기추종의 가능성이 추종시차에 관계없이 높게 나타났으며, 외국인에 대한 추종 및 군집행동의 증거는 확인할 수 없었다.