응급의학과 의사가 시행한 상복부 초음파의 정확성

하영록,김훈,유승,정성필,김승환,유인술 대한응급의학회 2002 대한응급의학회지 Vol.13 No.4

Purpose: The purpose of this study is to determine for upper abdominal pain, the accuracy of emergency abdominal ultrasonography (EAU) performed by emergency physicians with limited training. Methods: Two PGY-3 emergency physicians, who had received 2 hours of hands-on training, including the normal anatomy of a biliary system, liver, kindney, spleen, and pancreas, and who had studied the pathologic findings for another month were the subjects of this study. They used a Sonosite 180? to perform EAU on patients with upper abdominal pain within 2 months after training. We determined the agreement between the radiologist’s abdominal ultrasonography(RAU) and EAU by using Kappa statistics. Results: A total of 59 patients were enrolled. The agreement between the EAU and the RAU findings was 0.97, 0.88, 0.79, 0.73, 0.62, and 0.57 for gall bladder (GB) distension, cholelithiasis, GB wall thickening, duct dilatation, choledocholithiasis, and pericholecystic fluid, respectively (p<0.05). Conclusion: The results of EAU, performed by emergency physician with limited training on patients suffering from upper abdominal pain had a significant agreement with the RAU. However, more educations and cautions are warranted for diagnosing pericholecystic fluid and choledocholithiasis.

노인 외상 환자의 중증도 분류 시 Triage-revised Trauma Score의 의의

양영모,하영록,정성필,김승환,유인술 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Backgrouds: The mortality of geriatric trauma patients is higher than that of other age groups. However, little research has been done the methods or criteria of triage for geriatric trauma patients. This study evaluated a clinical significance of the triage-revised trauma score(t-RTS) for triage of geriatric trauma patients. Methods: We retrospectively analyzed clinical data on 528 trauma patients over 65 years of age who were treated from Jan 1999 to Dec 2000. The t-RTS was calculated utilizing the RR(respiratory rate), SBP(systolic BP), and GCS scores and the ISS was abstracted from the final diagnosis. The obtained t-RTS and ISS were evaluated using the measures of sensitivity, specificity, accuracy, and AUC curve. Results: The overall mortality rate was 9%, and there was no significant differences between the survival group and the mortality group according to age and sex. The mean scores of SBP, RR and GCS of the survival group were significantly higher than those of mortality group(p=0.001). The mean of t-RTS and RTS of the survival group were also significantly higher(p=0.001), but the ISS was significantly higher in the mortality group(p=0.001). The t-RTS, RTS, and ISS showed good prediction rates on the ROC curve(p=0.001), and the AUC value was higher in the ISS than in the t-RTS and the RTS. The sensitivity and the accuracy were high in the t-RTS and the RTS, and the specificity was high in the ISS. The t-RTS is less than 10 for a survival probability of 50% or less Conclusions: Implementation of the t-RTS in the triage of geriatric trauma patients in the field and in emergency room would be very useful. The probability of death in geriatric trauma patients is high when the t-RTS is less than 10.

응급실에서의 확산강조 자기공명 영상

정성필,이석우,양영모,하영록,김승환,유인술 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: This study was designed to review the cases of patients who had undergone diffusion-weighted magnetic resonance imaging(DWI) in the emergency department(ED), and to investigate its clinical usefulness and current indications. Methods: We analyzed the cases of 152 consecutive patients who underwent DWI in the ED from Jan to Mar 2001. DWI was obtained with the use of a multislice, single-shot, spin-echo plana imaging technique(GE SignaR). Imaging time was less than one minute. The medical records, the DWI films and the computed topography results were reviewed. We investigated the chief complaint, initial findings of physical examination, final diagnosis, decision-making department, interval from admission to imaging, and DWI findings. Results: DWI showed positive findings of high signal intensity in 84 patients(55.3%). Among the 68 patients who yielded a negative result, false negative occurred with 12 patients(17.6%): 10 lacunar infarctions, a pons infarction, and a brainstem infarction. Eleven patients were determined as having a cerebral hemorrhage, all of whom showed the abnormal finding of a mixed signal in DWI. The sensitivity and the specificity of DWI to rule out stroke were 85.5% and 98%, respectively. Current indications for DWI in our ED are age older than 60, alert mental status, and one of the symptoms or signs among lateralyzing sign, language disturbance, and dizziness/vertigo. Conclusion: DWI was highly specific to rule out stroke, so emergency care professionals should be familiar with this new technology. Further prospective study is required to determine the proper indications and clinical usefulness of DWI in the ED.

Thank You Ultrasound

Young-Rock Ha 대한외과학회 2021 대한외과학회 학술대회 초록집 Vol.2021 No.11

Purification of Wastewater From Paper Factory by Superconducting Magnetic Separation

Dong-Woo Ha,Tae-Hyung Kim,Myung-Hwan Sohn,Jun-Mo Kwon,Seung-Kyu Baik,Rock-Kil Ko,Sang-Soo Oh,Hong-Soo Ha,Ho-Sup Kim,Young-Hun Kim,Tae-Wook Ha IEEE 2010 IEEE transactions on applied superconductivity Vol.20 No.3

<P>It is environmentally important to recycle the wastewater, since paper factories use a large amount of water and equivalent amount of wastewater is generated. Conventional water treatment facilities like precipitation process need large-scale equipment and wide space to purify the wastewater of paper factory. In case of massive waste water, high gradient magnetic separation (HGMS) parts are more effective to purify it rapidly and to occupy relatively small space, since large voids at filter with HGMS are adopted. In this respect, we prepared two types of superconducting magnets in order to apply HGMS parts for wastewater purification process. We made cryo-cooled Bi-2223 (HTS) superconducting magnet parts with room temperature bore in diameter of 70 mm and 200 mm in height. Also, cryo-cooled Nb-Ti superconducting magnet with room temperature bore in diameter of 100 mm and 600 mm in height was used for magnetic separator. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The faster wastewater's flow rate was, the worse the degree of clarity in treated water was. The ability of wastewater treatment in the case of magnetic separation used with 10 of magnetite particles was better than that in the case of 5 of magnetite particles.</P>

응급센터에 내원한 외상환자에서 간과된 골절의 요인 분석

박득현 ( Deuk Hyun Park ),이성실 ( Sung Sil Lee ),김동언 ( Dong Un Kim ),조현영 ( Hyun Young Cho ),이영근 ( Young Geun Lee ),김준수 ( Jun Su Kim ),전진 ( Jin Jun ),김영식 ( Young Sik Kim ),하영록 ( Young Rock Ha ),신태용 ( Tae Yo 대한외상학회 2009 大韓外傷學會誌 Vol.22 No.1

Purpose: A missed fracture is a very common occurrence in the Emergency Department (ED) and can have serious results because of delays in treatment, resulting in long-term disability. It is also one of the most common causes leading to medical legal issues. We analyzed the causes of missed fractures by using a bone scan which is known to be an effective tool for diagnosing bony lesions. Methods: We reviewed the medical records of trauma patients who underwent a bone scan after being discharged the ED from September 2006 to March 2008. Cases of missed fractures were identified by using electronic medical records to review each diagnosis. Definition of missed fracture was read after bone scan by radiologist. We decided that there was no fracture if we read `trauma-related lesion` or `cannot rule out fracture` on a bone scan read by a radiologist. Enrolled patients were analyzed by age, sex, time until bone scan and Injury Severity Score (ISS). Patients were divided into two groups, alert mentality and not-alert mentality, so there were split between a diagnosis group and a missed fracture group. ISS was also used in determining the severity of the patient`s injury upon discharge from the ED. Results: A total of 532 patients were enrolled in this study. Of those, 487 patients were in the diagnosis group, and 45 patients (8.4%) were discovered to have had a fracture. Of the 45 missed fracture patients, 34 patients (6.4%) had one-site fractures, 8 patients (1.5%) had two-site fractures, and 3 patients (0.6%) had threesite fractures. The most commonly missed fracture was multiple rib fractures (18 patients, 30.5%), followed by lumbosacral (LS) spine fractures (10 patients, 16.9%), thoracic spine fractures (8 patients, 13.6%), and clavicle fractures (6 patients, 10.2%). Mean age was 50.12±18.54 years in the diagnosis group and 57.38±16.88 years in the missed fracture group. For the diagnosis group, the mean ISS was 9.03±8.26, but in the missed fracture group it was17.53±9.69. Missed fractures were much more frequent in the not-alert mentality (p<0.01) and in the high ISS (ISS≥16) group (p<0.01). Conclusion: Missed fractures occur most frequent in patients of old age, not-alert mentality, and high ISS. Multiple rib and spine fractures were found to be the most frequent missed fractures, regardless of trauma severity. This study also shows a high possibility of clavicle and scapula fractures in patients with severe trauma. (J Korean Soc Traumatol 2009;22:37-43)

손목 관절과 발목 관절 손상 환자의 진단에 있어 응급 초음파의 유용성

이성실 ( Sung Sil Lee ),김동언 ( Dong Un Kim ),박득현 ( Deuk Hyun Park ),조현영 ( Hyun Young Cho ),안성준 ( Seung Jun Ahn ),고찬영 ( Chan Young Kho ),신태용 ( Tae Yong Shin ),김영식 ( Young Sik Kim ),하영록 ( Young Rock Ha ) 대한외상학회 2007 大韓外傷學會誌 Vol.20 No.2

Purpose: Ultrasound is of proven accuracy in abdominal and thoracic trauma and may be useful for diagnosing extremity injury in situations where radiography is not available, such as disasters and military and space applications. However, the diagnosis of fractures is suggested by history and physical examination and is typically confirmed with radiography. As a alternative to radiography, we prospectively evaluated the utility of extremity ultrasound performed by trained residents of emergency medicine (EM) one patient with wrist and ankle extremity injuries. Methods: Initially, residents of EM performed physical examinations for fractures. The emergency ultrasound (EM US) was performed by trained residents, who used a portable ultrasound device with a 10- to 5-MHz linear transducer, on suspected patients before radiography examination. The results of emergency ultrasound and radiography and the final diagnosis were recorded, and correlations among them were determined by using Kappa`s test. Results: Thirty-nine patients were enrolled in our study. The average age was 36.6±19.3 years. There were radius Fx. (n=21), radius-ulna Fx. (n=1), ulna Fx. (n=1), and contusion (n=2) injuries among the wrist injury and lat.-med. malleolar Fx. (n=13), lat. malleolar Fx. (n=6), and med. malleolar Fx. (n=3) injuries among the ankle injury. Comparing EM US with radiography, we found the sensitivity, specificity, positive predictive value, and negative predictive value of EM US for Fx. diagnosis to be 100%, 66.7%, 97.3%, 100% and those of radiography to be 97.2%, 100%, 100%, and 75%, respectively. Kappa`s test for a correlation between the Fx. diagnosis of EM US and the final diagnosis of Fx was performed, and Kappa`s value was 0.787 (P = 0.004). Conclusion: EM US for Fx. can be performed quickly and accurately by EM residents with excellent accuracy in remote locations such as disaster areas and in military and aerospace applications. EM US was as useful as radiography in our study and had a high correlation to the final diagnosis of Fx. Therefore, ultrasound should performed on patients with extremity injury to determine whether extremity evaluation should be added to the FAST (focused abdominal sonography trauma) examination. (J Korean Soc Traumatol 2007;20:130-137)

Characterization and Modeling of 1/<tex> $f$</tex> Noise in Si-nanowire FETs: Effects of Cylindrical Geometry and Different Processing of Oxides

Rock-Hyun Baek,Chang-Ki Baek,Hyun-Sik Choi,Jeong-Soo Lee,Yun Young Yeoh,Kyoung Hwan Yeo,Dong-Won Kim,Kinam Kim,Kim, D M,Yoon-Ha Jeong IEEE 2011 IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol.10 No.3

<P>In this paper, the volume trap densities <I>Nt</I> are extracted from gate-all-around silicone-nanowire FETs with different gate oxides, using a cylindrical-coordinate-based flicker noise model developed. For extracting <I>Nt</I>, the drain-current power spectral densities were measured from a large number of identical devices and averaged over, thereby mimicking the spatial distribution of trap sites inducing 1/<I>f</I> curve. Also, effective mobility and threshold voltage were simultaneously extracted with the series resistance to characterize the 1/<I>f</I> noise in terms of intrinsic values of these two channel parameters. The volume trap densities thus extracted from different oxides (in situ steam-generated oxide/rapid thermal oxide/nitride-gated oxide) are compared and further examined using hot-carrier stress data. Finally, radius dependence of the cylindrical 1/<I>f</I> model developed is discussed.</P>

Characteristics of the Series Resistance Extracted From Si Nanowire FETs Using the <tex> $Y$</tex> -Function Technique

Rock-Hyun Baek,Chang-Ki Baek,Sung-Woo Jung,Yun Young Yeoh,Dong-Won Kim,Jeong-Soo Lee,Kim, D.M.,Yoon-Ha Jeong IEEE 2010 IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol.9 No.2

<P>The series resistance, <I>R</I> <SUB>sd</SUB> in silicon nanowire FETs (Si-NWFET) is extracted unambiguously, using the <I>Y</I> -function technique, in conjunction with the drain current and transconductance data. The volume channel inversion in Si-NWFET renders the charge carriers relatively free of the surface scattering and concomitant degradation of mobility. As a result, the <I>Y</I> -function of Si-NWFET is shown to exhibit a linear behavior in strong inversion, thereby enabling accurate extraction of <I>R</I> <SUB>sd</SUB>. The technique is applied to nanowire devices with channel lengths 82, 86, 96, 106, 132, and 164 nm, respectively. The extracted <I>R</I> <SUB>sd</SUB> values are shown nearly flat with respect to the gate voltage, as expected from Ohmic contacts but showed a large variation for all channel lengths examined. This indicates the process parameters involved in the formation of series contacts vary considerably from device to device. The present method only requires a single device for extraction of <I>R</I> <SUB>sd</SUB> and the iteration procedure for data fitting is fast and stable.</P>

<tex> $C$</tex>– <tex> $V$</tex> Characteristics in Undoped Gate-All-Around Nanowire FET Array

Rock-Hyun Baek,Chang-Ki Baek,Sang-Hyun Lee,Sung Dae Suk,Ming Li,Yun Young Yeoh,Kyoung Hwan Yeo,Dong-Won Kim,Jeong-Soo Lee,Kim, D M,Yoon-Ha Jeong IEEE 2011 IEEE electron device letters Vol.32 No.2

<P>Presented in this letter are the <I>C</I>-<I>V</I> data, measured from nanowire capacitors, which have been fabricated by connecting in parallel a large number of identically processed nanowire FETs. The <I>C</I>-<I>V</I> curves were examined over a range from accumulation to inversion with varying frequencies and at different electrode configurations. The gate response of the undoped and floating channel is investigated using <I>C</I>-<I>V</I> data, and the inversion charge and carrier mobility are accurately extracted by eliminating the effects of parasitic capacitances and series resistance <I>R</I><SUB>sd</SUB>. These observed data are compared with the data from planar MOS capacitor.</P>