• 제목/요약/키워드: Potential intensity

검색결과 752건 처리시간 0.03초

Magnetic Resonance-Guided Focused Ultrasound in Neurosurgery: Taking Lessons from the Past to Inform the Future

  • Jung, Na Young;Chang, Jin Woo
    • Journal of Korean Medical Science
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    • 제33권44호
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    • pp.279.1-279.16
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    • 2018
  • Magnetic resonance-guided focused ultrasound (MRgFUS) is a new emerging neurosurgical procedure applied in a wide range of clinical fields. It can generate high-intensity energy at the focal zone in deep body areas without requiring incision of soft tissues. Although the effectiveness of the focused ultrasound technique had not been recognized because of the skull being a main barrier in the transmission of acoustic energy, the development of hemispheric distribution of ultrasound transducer phased arrays has solved this issue and enabled the performance of true transcranial procedures. Advanced imaging technologies such as magnetic resonance thermometry could enhance the safety of MRgFUS. The current clinical applications of MRgFUS in neurosurgery involve stereotactic ablative treatments for patients with essential tremor, Parkinson's disease, obsessive-compulsive disorder, major depressive disorder, or neuropathic pain. Other potential treatment candidates being examined in ongoing clinical trials include brain tumors, Alzheimer's disease, and epilepsy, based on MRgFUS abilities of thermal ablation and opening the blood-brain barrier. With the development of ultrasound technology to overcome the limitations, MRgFUS is gradually expanding the therapeutic field for intractable neurological disorders and serving as a trail for a promising future in noninvasive and safe neurosurgical care.

다중운동 프로그램이 만성 요통 환자의 통증 강도, 몸통 근력 및 오스웨스트리 장애지수에 미치는 영향 (Effects of a Multi-modal Exercise Program on Pain Intensity, Trunk Muscle Strength, and Oswestry Disability Index in Patients with Chronic Low Back Pain)

  • 박찬호;김재철;양영식
    • 대한정형도수물리치료학회지
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    • 제26권2호
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    • pp.19-27
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    • 2020
  • Background: The purpose of this study was to examine the effects of a multi-modal exercise program for patients with chronic low back with respect to pain intensity, trunk muscle strength and Oswestry disability index. Methods: Thirty patients with chronic low back pain were recruited and divided equally into two groups. The multi-modal training program comprised a series of exercises such as warm-up, stabilization exercises, stretching, endurance exercises, and cool down whereas the control group performed only stabilization exercises. The both group spent an equal amount of time performing 60 minutes per day, three times per week, for five weeks. Results: The experimental group demonstrated statistically significant improvements in range of motion, trunk muscle strength, the visual analogue scale, and the Oswestry Disability Index (p<.05). Intergroup comparison showed a statistically significant difference in the range of motion of the lumbar spine and the degree of disability in the experimental group. Muscle strength and pain were statistically significant in both groups. Conclusion: The multi-modal exercise program is effective for patients with chronic low back pain, as it reduces lower back pain, increases trunk muscles strength, and decrease the potential for becoming disabled.

전단파 속도가 중저층 철근콘크리트 구조물의 지진 응답에 미치는 영향 (Effect of Shear Wave Velocity on Seismic Response of Low- and Mid-Rise Reinforced Concrete Frames)

  • 김민선;이창석;김병민;전종수
    • 한국지진공학회논문집
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    • 제28권5호
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    • pp.249-255
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    • 2024
  • Strong ground motions at specific sites can cause severe damage to structures. Understanding the influence of site characteristics on the dynamic response of structures is crucial for evaluating their seismic performance and mitigating the potential damage caused by site effects. This study investigates the impact of the average shear wave velocity, as a site characteristic, on the seismic response of low-to-medium-rise reinforced concrete buildings. To explore them, one-dimensional soil column models were generated using shear wave velocity profile from California, and nonlinear site response analyses were performed using bedrock motions. Nonlinear dynamic structural analyses were conducted for reinforced concrete moment-resisting frame models based on the regional information. The effect of shear wave velocity on the structural response and surface ground motions was examined. The results showed that strong ground motions tend to exhibit higher damping on softer soils, reducing their intensity, while on stiffer soils, the ground motion intensity tends to amplify. Consequently, the structural response tended to increase on stiffer soils compared to softer soils.

인삼(人蔘)잎의 수분(水分) Potential과 광합성(光合成) (Water Potential and Photosynthesis of Korean Ginseng (Panax ginseng C. A. Meyer) Leaves)

  • 이강수;오상선;최선영;류점호
    • 한국약용작물학회지
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    • 제2권1호
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    • pp.86-94
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    • 1994
  • 인삼(人蔘)의 광합성(光合成)이 콩보다 낮은 원인(原因)을 밝혀 인삼(人蔘)의 수량증대(收量增大)와 육종(育種)을 위한 기초자료(基礎資料)로 삼고저 자경종(紫莖種) 2년생(年生) 인삼식물(人蔘植物)에서 분리(分離)한 잎을 재료(材料)로 광합성(光合成)과 수분함량(水分含量), 기공식도도(氣孔植導度), 그리고 수분(水分) potential을 조사(調査)하고 콩과 비교(比較)하였다. 1. 동일(同一)한 광도(光度)에서 광합성(光合成)은 인삼(人蔘)이 콩보다 작았으며 광합성(光合成)에 대한 포화광도(飽和光度)도 약 $30{\mu}E\;/\;m^2\;/\;s$로 콩의 약 $800{\mu}E\;/\;m^2\;/\;s$보다 낮았다. 2. 분리(分離)한 잎에서 광합성(光合成)은 인삼(人蔘)이 콩보다 빠르게 감소(減少)하였으며 $20^{\circ}C$에서보다 $30^{\circ}C$에서 더 빨랐다. 또한 광합성(光合成)이 정지(停止)하는 시간(時間)도 인삼(人蔘)잎이 콩잎보다, $20^{\circ}C$에서보다 $30^{\circ}C$에서 더 짧았다. 3. 잎의 수분감소(水分減少速度)는 인삼(人蔘)이 콩보다 느렸고 광합성(光合成)이 정지(停止)되는 수분함량(水分含量)은 인삼(人蔘)잎(약$70{\sim}71%$)이 콩잎$(50{\sim}63%)$보다 높았다. 4. 수분함량(水分含量)파 광합성(光合成)과는 인삼(人蔘)과 콩 모두 온도(溫度)에 무관(無關)하게 각각(各各) 고도(高度)의 정(正)의 상관(相關)이 있었는데, 광합성(光合成)은 동일(同一)한 수분함량(水分含量)에서 인삼(人蔘)이 콩보다작았다. 5. 기공식도도(氣孔傳導度)와 광합성(光合成)과는 인삼(人蔘)과 콩 모두 두 온도(溫度)$(20^{\circ}C,\;30^{\circ}C)$에서 무관(無關)하게 고도(高度)의 정(正)의 상관(相關)이 있었으며, $20^{\circ}C$에서는 인삼(人蔘)의 기공식도도(氣孔傳導度) 범위(範圍)$(40mmo1\;/\;m^2\;이하)$에서 인삼(人蔘)과 콩의 광합성양(光合成量)은 비슷하였다. 6. 수분(水分) potential 엽수분함량(葉水分含量)이 동일(同一)한 조건(條件)에서 콩보다 인삼(人蔘)이 낮았으며, 수분(水分) potential과 광합성(光合成) 및 기공식도도(氣孔傳導度)와는 고도(高度)의 정(正)의 상관(相關)이있었다. 7. 이상(以上)의 결과(結果)를 종합(綜合)해 볼 때, 인삼(人蔘)의 광합성(光合成)이 타식물(他植物)보다 낮은 것은 기공식도도(氣孔傳導度)와 수분(水分) potential이 낮은 것과도 밀접(密接)한 관계(關係)가 있을 것으로 생각된다.

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생체조직내 레이저 광 밀도 향상을 위한 압력 인가형 저출력 레이저 프로브 (A Pressure Applied Low-Level Laser Probe to Enhance Laser Photon Density in Soft Tissue)

  • 여창민;박정환;손태윤;이용흠;정병조
    • 대한의용생체공학회:의공학회지
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    • 제30권1호
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    • pp.18-22
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    • 2009
  • Laser has been widely used in various fields of medicine. Recently, noninvasive low-level laser therapeutic medical devices have been introduced in market. However, low-level laser cannot deliver enough photon density to expect positive therapeutic results in deep tissue layer due to the light scattering property in tissue. In order to overcome the limitation, this study was aimed to develop a negative pressure applied low-level laser probe to optimize laser transmission pattern and therefore, to improve photon density in soft tissue. In order to evaluate the possibility of clinical application of the developed laser probe, ex-vivo experiments were performed with porcine skin samples and laser transmissions were quantitatively measured as a function of tissue compression. The laser probe has an air suction hole to apply negative pressure to skin, a transparent plastic body to observe variations of tissue, and a small metallic optical fiber guide to support the optical fiber when negative pressure was applied. By applying negative pressure to the laser probe, the porcine skin under the metallic optical fiber guide is compressed down and, at the same time, low-level laser is emitted into the skin. Finally, the diffusion images of laser in the sample were acquired by a CCD camera and analyzed. Compared to the peak intensity without the compression, the peak intensity of laser increased about $2{\sim}2.5$ times and FWHM decreased about $1.67{\sim}2.85$ times. In addition, the laser peak intensity was positively and linearly increased as a function of compression. In conclusion, we verified that the developed low-level laser probe can control the photon density in tissue by applying compression, and therefore, its potential for clinical applications.

Locoregionally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy plus concurrent weekly cisplatin with or without neoadjuvant chemotherapy

  • Wee, Chan Woo;Keam, Bhumsuk;Heo, Dae Seog;Sung, Myung-Whun;Won, Tae-Bin;Wu, Hong-Gyun
    • Radiation Oncology Journal
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    • 제33권2호
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    • pp.98-108
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    • 2015
  • Purpose: The outcomes of locoregionally advanced nasopharyngeal carcinoma patients treated with concurrent chemoradiation (CCRT) using intensity-modulated radiotherapy (IMRT) with/without neoadjuvant chemotherapy (NCT) were evaluated. Materials and Methods: Eighty-three patients who underwent NCT followed by CCRT (49%) or CCRT with/without adjuvant chemotherapy (51%) were reviewed. To the gross tumor, 67.5 Gy was prescribed. Weekly cisplatin was used as concurrent chemotherapy. Results: With a median follow-up of 49.4 months, the 5-year local control, regional control, distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival rates were 94.7%, 89.3%, 77.8%, 68.0%, and 81.8%, respectively. In multivariate analysis, the American Joint Committee on Cancer stage (p = 0.016) and N stage (p = 0.001) were negative factors for DMFS and DFS, respectively. Overall, NCT demonstrated no benefit and an increased risk of severe hematologic toxicity. However, compared to patients treated with CCRT alone, NCT showed potential of improving DMFS in stage IV patients. Conclusion: CCRT using IMRT resulted in excellent local control and survival outcome. Without evidence of survival benefit from phase III randomized trials, NCT should be carefully administered in locoregionally advanced nasopharyngeal carcinoma patients who are at high-risk of developing distant metastasis and radiotherapy-related mucositis. The results of ongoing trials are awaited.

SHALSTAB을 이용한 산사태 위험지 예측 (The Prediction of Landslide Potential Area Using SHALSTAB)

  • 장현석;이상희;김재수
    • 한국산림과학회지
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    • 제103권2호
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    • pp.218-225
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    • 2014
  • 최근 우리나라에서는 집중호우로 인하여 산사태의 발생이 증가하며 인명 및 재산피해가 늘고 있다. 본 연구에서는 산사태 발생에 직접적으로 영향을 주는 강우강도에 따른 산사태 위험지를 예측하고자 SHALSTAB(Shallow Landsliding Stability Model)을 이용하였다. SHALASTAB의 매개변수인 투수량계수의 값은 $19.58m^2/day$, 내부마찰각은 $36.3^{\circ}$, 포화단위중량은 $2.03t/m^3$로 결정되었다. 이러한 매개변수를 이용하여 구한 지형지수에 따라서 본 연구지역의 사면안정 상태를 무조건 안정, 안정, 불안정, 무조건 불안정의 4가지 형태로 구분하였다. SHALSTAB의 적용성을 평가하고자 기존에 발생하였던 263 mm 강우에서 사면이 불안정해지는 지역과 산사태 발생지에 대한 데이터베이스를 구축하여 이를 비교하였다. 정확도 검정 결과 85.1% 일치하였다. SHALSTAB을 이용하여 강우강도에 따른 산사태 발생 위험지역을 판별하는데 활용이 가능한 것으로 생각된다.

자외선 조사가 Ovalbumin의 분자적 성질에 미치는 영향 (Effect of Ultraviolet Irradiation on Molecular Properties of Ovalbumin)

  • 조용식;송경빈;산전경로;한귀정
    • Applied Biological Chemistry
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    • 제51권4호
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    • pp.276-280
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    • 2008
  • 식품 allergen 저감화 수단으로 자외선 조사의 타당성을 검토하고 자외선조사가 식품 단백질의 분자적 성질에 미치는 영향을 조사하고자 ovalbumin 용액에 자외선을 조사한 후 단백질의 분자량 분포와 2차구조 및 3차구조의 변화를 조사하였다. SDS-PAGE와 Gel permeation chromatography 결과 ovalbumin은 자외선 조사에 의하여 단백질이 분해되고 조사시간이 증가할수록 펩티드가 중합하는 형태를 나타냈다. Circular dichroism 연구는 자외선 조사에 의하여 ${\alpha}$-helix 구조가 감소하고 조사시간이 증가할 경우 compact denatured ovalbumin의 구조를 나타내는 2차구조의 변화를 나타냈다. 자외선 조사된 ovalbumin의 형광스펙트럼은 조사시간이 증가할수록 단백질의 maximum emission intensity가 감소하는 3차구조의 변화를 나타냈다. 결과적으로 자외선 조사는 ovalbumin의 분자적 성질을 변화시키며 allergen의 항원성을 변화시키는 수단으로 이용가능성을 시사한다.

전기자극의 강도와 측정전극의 간격이 감각신경신호의 파라미터에 미치는 영향 연구 (The Effects of the Stimulation Intensity and Inter-Electrode Distance on the Parameters of the Measured Sensory Nerve Signal)

  • 임경민;송동진
    • 대한의용생체공학회:의공학회지
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    • 제35권6호
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    • pp.234-241
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    • 2014
  • This study was designed to investigate the effects of stimulation intensity and inter-electrode distance on the parameters of the measured sensory nerve signal. 30 healthy subjects participated in this study. Sensory nerve signals were elicited by four different pulse amplitudes, i.e., 3, 6, 9, 12 mA, with the pulse width fixed at $500{\mu}s$. The sensory nerve signals elicited by the four different pulse amplitudes were measured by four different inter-electrode distances (20, 30, 40, and 50 mm). We extracted four parameters (pulse amplitude, pulse width, pulse area, and latency time from stimulation) from the sensory nerve signals. The measured pulse amplitude and pulse width were increased when the measuring inter-electrode distance was increased while the stimulating pulse amplitude was fixed. The measured pulse amplitude was saturated with the stimulating pulse amplitudes of over 6 mA while measuring inter-electrode distance. Under the same condition, measured pulse width was increased, and sensory nerve signal was initiated early. Sensory nerve signals, specially those of pulse amplitude, were distorted by a differential amplification method that commonly measures the human body signal. The experimental results indicate that the differential amplification method is required to be replaced when measuring nerve signals. Our observations suggested that the hyperpolarization of the action potential of the sensory nerve signal for preventing distortion could be used to clarify the correlation between the parameters of the sensory nerve signals and quantification of sensations.

종이기반 농도 구배 형성 칩을 통한 포도당 발색 반응 검사 (A Colorimetric Glucose Assay via Concentration Gradient Paper Chip)

  • 김태훈;신현영;이윤일;태기식;김민석
    • 대한의용생체공학회:의공학회지
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    • 제38권6호
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    • pp.302-307
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    • 2017
  • This paper presents a paper-based concentration gradient chip to analyze colorimetric glucose assay. The paper-based concentration gradient chip was fabricated through a wax patterning technique that can design the fluidic channel by selectively printing hydrophobic and hydrophilic areas. Afterwards, glucose and dilution solutions were loaded into the inlet of a concentration gradient chip and each solution was then mixed sequentially at mixing channel. Finally, concentration gradient was formed at each outlet of the chip. To measure the glucose concentration of the solution in outlets, we conducted colorimetric glucose assay with fixed concentration of glucose solution (0, 5, 10, 15 and 20 mM) and obtained normalized intensity. Subsequently, glucose concentrations of the outlets were calculated by substituting the normalized intensity to linear regression function based on the normalized intensity of fixed glucose concentration. Finally, the concentration gradient of glucose was formed on the chip with the result of colorimetric assay. The concentration gradient paper chip has the potential to accurately analyze unknown glucose concentration.