• Title/Summary/Keyword: Cord angle

검색결과 64건 처리시간 0.018초

Combined Open Door Laminoplasty with Unilateral Screw Fixation for Unstable Multi-Level Cervical Stenosis : A Preliminary Report

  • Son, Seong;Lee, Sang Gu;Park, Chan Woo;Kim, Woo Kyung
    • Journal of Korean Neurosurgical Society
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    • 제53권2호
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    • pp.83-88
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    • 2013
  • Objective : The authors reviewed their experiences of combined surgery (open door laminoplasty with unilateral screw fixation) for unstable multi-level cervical stenosis, to clarify the situation regarding the surgical approach most appropriate for the treatment of diffuse unstable multi-level cervical stenosis. Methods : From January 2011 to January 2012, combined surgery was performed for unstable multi-level cervical stenosis by one surgeon at our institution. The subjects of this study were 6 men of mean age 53.7 years (range, 48-71) with a mean follow-up of 9.3 (range, 3-14) months. All imaging studies showed severe multi-level cervical stenosis with spinal cord signal change, and instability or kyphotic deformity. A retrospective review of clinical, radiological, and surgical data was conducted. Results : Average laminoplasty level was 4.8 and the average screw fixation level was 5.0. Japanese Orthopedic Association score improved from an average of 5.2 to 11.2 points. According to Nurick's grades and Odom's criteria, symptom improvement was statistically significant. On the other hand, Cobb's angle changes were not significant. Average operation time was 5.86 hours with an average blood loss of 460 mL. No significant surgical complication was encountered. Conclusion : Despite the small cohort and the short follow-up duration, the present study demonstrates that laminoplasty with unilateral screw fixation is a safe and effective treatment for unstable multi-level cervical stenosis.

과도 액정 기법을 이용한 와동발생기 하류의 유동장 및 열전달 측정 (Detailed Measurement of Flow and Heat Transfer Downstream of Rectanglar Vortex Generators Using a Transient Liquid Crystal Technique)

  • 홍철현;양장식;이기백
    • 대한기계학회논문집B
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    • 제27권11호
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    • pp.1618-1629
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    • 2003
  • The effects of the interaction between flow field and heat transfer caused by the longitudinal vortices are experimentally investigated using a five hole probe and a transient liquid crystal technique. The test facility consists of a wind tunnel with vortex generators protruding from a bottom surface and a mesh heater. In order to control the strength of the longitudinal vortices, the angle of attack of vortex generators used in the present experiment is 20$^{\circ}$, and the spacing between the vortex generators is 25mm. The height and cord length of the vortex generator is 20mm and 50mm, respectively. Three-component mean velocity measurements are made using a f-hole probe system, and the surface temperature distribution is measured by the hue capturing method using a transient liquid crystal technique. The transient liquid crystal technique in measuring heat transfer has become one of the most effective ways in determining the full surface distributions of heat transfer coefficients. The key point of this technique is to convert the inlet flow temperature into an exponential temperature profile using the mesh heater set up in the wind tunnel. The conclusions obtained in the present experiment are as follows: The two maximum heat transfer values exist over the whole domain, and as the longitudinal vortices move to the farther downstream region, these peak values show the decreasing trends. These trends are also observed in the experimental results of other researchers to have used the uniform heat flux method.

Usefulness of Simple Rod Rotation to Correct Curve of Adolescent Idiopathic Scoliosis

  • Kim, Ji Yong;Song, Kyungchul;Kim, Kyung Hyun;Rim, Dae Cheol;Yoon, Seung Hwan
    • Journal of Korean Neurosurgical Society
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    • 제58권6호
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    • pp.534-538
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    • 2015
  • Objective : To correct apical vertebral rotation for adolescent idiopathic scoliosis (AIS), direct vertebral derotation (DVD) or simple rod rotation (SRR) might be considered. The aim of the present study is to introduce the surgical experiences of AIS by a Korean neurosurgeon and to evaluate the effectiveness of SRR for apical vertebral rotation. Methods : A total of 9 patients (1 male and 8 females) underwent scoliosis surgery by a neurosurgeon of our hospital. The Lenke classifications of the patients were 1 of 1B, 2 of 1C, 1 of 2A, 1 of 2C, 3 of 5C and 1 of 6C. Surgery was done by manner of simple rod rotation on the concave side and in situ coronal bending. Coronal Cobb's angles, vertebral rotation angles and SRS-22 were measured on a plain standing X-ray and CT before and after surgery. Results : The mean follow up period was 25.7 months (range : 5-52). The mean number of screw positioning level was nine (6-12). The mean age was 16.4 years (range : 13-25) at surgery. The mean Risser grade was $3.7{\pm}0.9$. The apical vertebral rotation measured from the CT scans was $25.8{\pm}8.5^{\circ}$ vs. $9.3{\pm}6.7^{\circ}$ (p<0.001) and the Coronal Cobb's angle was $53.7{\pm}10.4^{\circ}$ vs. $15.4{\pm}6.5^{\circ}$ (p<0.001) preoperatively and postoperative, respectively. The SRS-22 improved from 71.9 preoperatively to 90.3 postoperatively. There were no complications related with the operations. Conclusion : SRR with pedicle screw instrumentation could be corrected successfully by axial rotation without complications. SRR might serve as a good option to correct AIS deformed curves of AIS.

와동 발생기 높이 변화에 대한 경계층 내의 유동장과 온도장에 관한 실험적 연구 (The Experimental Study of the Interaction Between the Flow rind Temperature Field and a Boundary Layer Due to a Variety of tole Height of a Vortex Generator)

  • 권수인;양장식;이기백
    • 대한기계학회논문집B
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    • 제26권1호
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    • pp.82-93
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    • 2002
  • The effects of the interaction between the flow and temperature field and a boundary layer due to a variety of the height of a vortex generator are experimentally investigated. The test facility consists of a boundary-layer wind tunnel with the vortex generator protruding from the bottom surface. In order to control the strength of the longitudinal vortices, the angle of attack and the spacing distance of the vortex generator are 20 degree and 40 mm, respectively. The height of the vortex generator (H) is 15 mm, 20 mm and 30 mm and the cord length of it is 50 mm. Three-component mean velocity measurements are made using a 5-hole probe system and the surface temperature distribution is measured by the hue capturing method using thermochromatic liquid crystals. By using the method mentioned above, the following conclusions are obtained from the present experiment. The boundary layer is thinned in the downwash region where the strong downflow and the lateral outflow of the boundary layer fluid occur and thickened in the upwash re,3ion where the longitudinal vortex sweeps low momentum fluid away from the bottom surface. In case that the height of the vortex generator increases, the averaged circulation and the maximum vorticity of the vortex pair decrease. The contours of the non-dimensional temperature show the similar trends fur all the cases (H=15 mm, 20 mm and 30 mm). The peak augmentation of the distribution of the local non-dimensional temperature occurs in the downwash region near the point of minimum boundary-layer thickness.

Dosimetric Comparison of Noncoplanar and Coplanar Volumetric Modulated Arc Therapy Plans for Esophageal Cancer

  • Park, So-Yeon
    • 한국의학물리학회지:의학물리
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    • 제31권4호
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    • pp.179-188
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    • 2020
  • Purpose: We compared noncoplanar volumetric modulated arc therapy (ncVMAT) plans to coplanar VMAT (cVMAT) plans by evaluating the dosimetric quality of each for esophageal cancer. Methods: Twenty patients treated for esophageal cancer with the cVMAT technique were retrospectively selected. The cVMAT plans consisted of three coplanar full arc beams. The ncVMAT plans consisted of two coplanar full arc beams and one noncoplanar partial arc beam ranging from 45° to 315° with a couch rotation angle of 315°±5°. For dosimetric evaluation, the dose-volumetric (DV) parameters of the planning target volume (PTV) and organs at risk (OARs) were calculated for all VMAT plans. Results: No clinically noticeable differences between the cVMAT and ncVMAT plans were observed in the DV parameters of the PTV. For the lungs, the V13 Gy and mean dose for ncVMAT plans were smaller than those for cVMAT plans, showing statistically significant differences. For the heart, the values of the maximum dose for cVMAT and ncVMAT plans were 53.8±2.9 and 50.9±3.3 Gy, respectively (P=0.004). For the spinal cord, the values of the maximum dose for cVMAT and ncVMAT plans were 37.1±5.1 and 34.7±5.7 Gy, respectively (P<0.001). Conclusions: The use of ncVMAT plans provides better PTV coverage and sparing of OARs compared to that of cVMAT plans for long, tube-like esophageal cancer. For esophageal cancer, the ncVMAT plans showed a more favorable plan quality than the cVMAT plans.

수동 휠체어 추진 속도에 따른 상지 관절 생체역학적 영향 분석 (Upper Extremity Biomechanics of Manual Wheelchair Propulsion at Different Speeds)

  • 황선홍
    • 대한의용생체공학회:의공학회지
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    • 제43권4호
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    • pp.241-250
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    • 2022
  • It is known that chronic pain and injury of upper limb joint tissue in manual wheelchair users is usually caused by muscle imbalance, and the propulsion speed is reported to increase this muscle imbalance. In this study, kinematic variables, electromyography, and ultrasonographic images of the upper limb were measured and analyzed at two different propulsion speeds to provide a quantitative basis for the risk of upper extremity joint injury. Eleven patients with spinal cord injury for the experimental group (GE) and 27 healthy adults for the control group (GC) participated in this study. Joint angles and electromyography were measured while subjects performed self-selected comfortable and fast-speed wheelchair propulsion. Ultrasound images were recorded before and after each propulsion task to measure the acromiohumeral distance (AHD). The range of motion of the shoulder (14.35 deg in GE; 20.24 deg in GC) and elbow (5.25 deg in GE; 2.57 deg in GC) joints were significantly decreased (p<0.001). Muscle activation levels of the anterior deltoid, posterior deltoid, biceps brachii, and triceps brachii increased at fast propulsion. Specifically, triceps brachii showed a significant increase in muscle activation at fast propulsion. AHD decreased at fast propulsion. Moreover, the AHD of GE was already narrowed by about 60% compared to the GC from the pre-tests. Increased load on wheelchair propulsion, such as fast propulsion, is considered to cause upper limb joint impingement and soft tissue injury due to overuse of the extensor muscles in a narrow joint space. It is expected that the results of this study can be a quantitative and objective basis for training and rehabilitation for manual wheelchair users to prevent joint pain and damage.

원발성 폐암에서 정위적 체부 방사선치료의 빔 배열에 따른 선량분포의 비교 (Comparison of the Dose Distributions with Beam Arrangements in the Stereotactic Body Radiotherapy (SBRT) for Primary Lung Cancer)

  • 예지원
    • 한국의학물리학회지:의학물리
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    • 제25권2호
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    • pp.110-115
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    • 2014
  • 원발성 폐암의 정위적 체부 방사선치료(Stereotatic Body Radiation Therapy; SBRT)시에, 종양주위의 빔 배열을 균등하게 한 $360^{\circ}$회전각도(Equally angles; EA)와 종양주위의 빔 배열을 부분각도(Partially angles; PA)로 배열한 치료계획의 선량차이를 확인하기 위하여, 세기조절방사선치료(Intensity-modulated radiation therapy, IMRT)와 체적변조회전치료(Volumetric-modulated arc therapy, VMAT)의 종양의 선량, 동측 폐의 선량, 반대측 폐의 선량, 손상위험장기(Organ at risk, OAR)의 선량, 치료효율 등을 비교분석 하였다. 12명의 환자에서 각각 4종류($IMRT_{EA}$, $IMRT_{PA}$, $VMAT_{EA}$, $VMAT_{PA}$)의 치료계획을 생성하였으며, 처방선량은 총 선량 60 Gy, 4회 분할치료로 표적체적 95%에 대해 100% 선량이 포함되게 하였다. IMRT와 VMAT의 치료계획 평가에서 $360^{\circ}$회전각도의 빔 균등배열과 부분각도 빔 배열에서 변수중 선량일치지수, 균질성지수, 고선량 유출, $D_{2cm}$, $R_{50}$은 빔 배열에 따라 크게 차이가 나지 않았다. 또한 손상위험장기인 척수, 기관지, 식도의 최고선량은 각각의 방법에 따라 차이를 나타내었다. 특히 $HDS_{location}$에서 21.63%와 26.46%의 큰 차이를 나타내었다.

경추부의 후관절 나사못 고정술에서 단피질삽입법과 양피질 삽입법 간의 특성에 관한 비교 (Comparisons of Unicortical and Bicortical Lateral Mass Screws in the Cervical Spine : Safety vs Strength)

  • 박춘근;황장회;지철;이재언;성재훈;최승진;이상원;;박성찬;조경석;박춘근;강준기
    • Journal of Korean Neurosurgical Society
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    • 제30권10호
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    • pp.1210-1219
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    • 2001
  • 서 론 : 후방 경유 경추 융합을 위한 후관절 금속판 고정술은 외상성 및 퇴행성 불안정성의 치료에 효과적인 방법이다. 후관절 금속판 고정의 안정성은 여러 가지 인자에 의해 결정된다. 이중 하나가 나사못의 삽입깊이이다. 이 방법이 처음 소개될 때에는 양피질골성 삽입이 이용되었다. 외과의사의 관심은 어떻게 안전하면서 생역학적으로 강력한 고정을 얻느냐에 있다. 목 적 : 이 연구의 목적은 사체에서 단피질성과 양피질성 나사못 삽입술을 시행한 후 안전성, pull-out 강도, 방사선학적 특성을 분석하고 나사못의 삽입에 대한 교육 훈련의 수준에 따른 영향을 평가하는데 있다. 방 법 : 평균 나이 78.9세인 21구의 사체에 대하여, Magerl의 기술을 변형하여 C3-C6(n=168)까지 3.5mm AO 나사못을 양쪽 후관절에 삽입하였다. 수술중 방사선 사진영상은 사용되지 않았다. 오른 쪽(단피질성 삽입)은 14mm 나사못(11mm의 유효 길이)을 이용하고, 왼쪽은 양피질성 삽입을 시도하였다. 각 사체는 3개의 군으로 나누어 척추 수술 수련의 수준이 다른 받은 3명의 척추 외과 의사들(전임 강사, 임상 강사, 수석 레지던트)이 수술을 시행했다. 수술 후 경추를 떼어내어 나사못의 위치를 육안적으로 확인하고 방사선학적으로 안정성과 삽입 위치 (1,2,3)를 평가하였다. 척수, 후관절, 신경근과 척추 동맥에 대한 나사못의 위치를"만족할 만한","위험한", 그리고"직접적인 손상"으로 구분하였다. material testing machine을 이용하여 모든 나사못에 대해서 Pull-out 강도를 측정하였다. 결 과 : 대다수의 나사못(92.9%)은 만족할 만한 상태였다. 전예에서 척수에 대한 위험성은 없다. 오른 편(단피질성 : 14mm) 나사못의 98.9%는"만족할 만한"에 속했다. 그리고 왼쪽 편(양피질성)의 68.1%는"만족할 만한"에 속했다. 양피질성 나사못 군에서 5.8%의 척추 동맥에 대한 직접적인 손상이 있었고 신경근의 직접적인 손상 발생율은 17.4%였다. 반면에 단피질성 나사못 군에서는 이들에 대한 직접적인 손상은 없었다. 양피질성 나사못에서 보인"직접 손상"의 거의 대부분은 외과 의사의 경험 부족으로 발생하였다. 나사못의 안정성과 삽입 위치 사이에는 특별한 관련이 없었다. 모든 나사못의 pull-out 강도는 $542.0{\pm}296.6N$였다. 단피질성에 있어서의 pull-out 강도($519.0{\pm}289.9N$)와 양피질성($565.2{\pm}306N$) 나사못에는 아무런 통계학적으로 의미있는 차이점을 발견할 수 없었다(p>0.05). 나사못 삽입위치와 pull-out 강도 사이에는 의미있는 차이가 없었다. 결 론 : 이번 연구는 경추 후관절 나사못 고정술시 단피질성과 양피질성 나사못의 안정성과 효능을 집중적으로 알아보았다. 명백한 것은 14mm의 나사못(효과적인 길이는 11mm)이 보다 긴 양피질성 나사못 보다 손상의 위험이 훨씬 낮고 거의 동등한 pull-out강도를 갖는다는 것이다. 또한, 수술시 방사선 영상을 사용할 수 없을 때, 훈련과 축적된 경험에 의해 나사못 삽입의 정확성과 안전성이 향상될 수 있다.

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Superimposed Rubber Pattern법에 의한 성인 정상 및 비정상 교합자의 교합 양상에 관한 연구 (A STUDY OF THE NORMAL & ABNORMAL OCCULSAL PATERNS IN ADULTS USING THE SUPERIMPOSED RUBBER PATTERN METHOD)

  • 최대균;이성복;권영혁;최부병
    • 대한치과보철학회지
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    • 제33권3호
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    • pp.467-491
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    • 1995
  • In order to analyze the occlusin of intercuspation with maximun bite force, fifteen healthy adult subjects with the ages 23 to 27 were studied(Group1 ; 5-normal occlusion with Angle's Class1, Group2 ; 5-Angle's Class2 malocclusion, Group3 ; 5-Angle’s Class3 malocclusion). Head Position was fixed with occlusal plane paralleling to horizontal line and occlusal registration r cord was made with polyether rubber impression material(Ramitec, ESPECo. West Germany). After all subject were trained for maximum intercuspation at least 5 times, occlusal registration procedure was repeated for this study. Lower posterior rubber occlusal registration records were sliced with 1mm thickness using precision metal sliding channel(Hitachi Ind. Co., Japan). Gross sectional drawings were traced from occluding view of upper and lower posterior teeth on the rubber slices using digitizer, and superimposed for the determination of each drawing distance(Superimposed Rubber Pattern Method). Based on superimposed rubber pattern drawings, total area of occlusal view, sum of each area of the 5 divided occlusal contact provinces and its ratio, total area and number of occlusal contact area were determined to elucidate occlusal stability in the normal and abnormal occlusion groups. The data were analysed by t-test(p=0.05) to determine statistical significance. The obtained results were as follows : 1. Group1 showed the largest standard area with occlusal view of the lower posterior teeth and Group3 showed the smallest area. There was a significant difference between Group2 and Group3(p=0.025), and Gropu1 was not statistically different for both Group2 and Group3. 2. Means and ratio of the under 2.0mm area(D) and ratio showed $197.49mm^2$, 59.76% in Group1, $188,69mm^2$, 56.10% in Group2, and $174.23mm^2$, 55.76% in Group3. The results that Group1 has the most area/ratio and Group3 has the least area/ratio can be considered Group1 is the most advantageous for masticatory effective area, and Group3 is the least adnantageous. 3. Means and ratio of the under 1.0mm area(C) were $198.96mm^2$, 42.65% in Group1, 123.06$mm^2$, 46.58% in Group2, and $92.24mm^2$, 29.52% in Group3. These data means that Group1 is the most advantageous in terms of masticatory effective area and Group3 is the least. 4. Means and ratio of the under 0.5mm area(B) were $86.68mm^2$, 26.68% in Group1, $62.98mm^2$, 18.71% in Group2, and $36.44mm^2$, 11.66% in Group3. These can also be considered Group1 is the most advantageous for masticatory effective area and occlusal stability. 5. Means and ratio of the under 0.05mm area(A) were $30.92mm^2$, 9.21% in Group1, $14.31mm^2$, 4.25% in Group2, and $7.59mm^2$, 2.43% in Group3. The area ratio of the each subject group was(4.1) : (1.9) : (1)and the data of the under 0.05mm area has the intimate relationship with inter-group and intra-group data/ratio. 6. First molar showed the most occlusal contact points in all subject group and Group1 showed somewhat uniformly distributed occlusal contact point except first premolar. In Group2, all contact point in posterior teeth showed significantly reduced distribution except first molar. Group3 showed evenly distributed contace points in first and second molars.

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후두개와 유표피낭종 : 10례 분석 (Epidermoid Tumor of Posterior Fossa : Analysis of 10 Cases)

  • 임효주;안재성;권양;이정교;권병덕
    • Journal of Korean Neurosurgical Society
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    • 제29권6호
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    • pp.744-747
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    • 2000
  • Objectives : The purpose of this study was to evaluate the clinical features of the epidermoid tumor of posterior fossa and to assess the surgical outcome. Methods : We reviewed the clinicoradiological records of 10 epidermoid tumor of posterior fossa, treated surgically at our hospital between 1991 and 1996. Results : The mean age of onset was 36 years old and mean duration of symptom was 5.2 years. Six were men and four were women. The location of tumors were cerebellopontine angle(CPA) 5 cases, cerebellum(Cbll)& 4th ventricle 3 cases, foramen magnum 1 case, and pineal region extended to Cbll and 4th ventricle 1 case. Common clinical features were trigeminal neuralgia in 3 cases, cerebellar signs 2 case, headache 2 cases, hemifacial spasm with deafness 1 case, cbll signs and multiple cranial nerve dysfunctions 1 case. One CPA epidermoid had no clinical symptom and sign associated with the tumor. The surgical approaches were suboccipital approach in 9 cases and one transcallosal approach to the tumor of pineal region. The extent of surgical removal was gross total resection in 5 cases and near total or subtotal resection in 5. Two patients with CPA tumor were complicated with facial paresis. One patient with tumor located in cerebellum extended into cisterna magna had postoperative vocal cord paresis. All complicated cases had severe adhesion of tumor capsule with brainstem or cranial nerve. The mean duration of follow up was 26 months. The overall outcome was improvement of symptoms and signs in 6 cases and stationary 4 cases. During follow up, imaging study was done in 7 patients and none of them had finding of tumor recurrence. Conclusion : We conclude that recurrence of tumor is rare in both total and subtotal resected cases, but long-term follow-up is required. Aggressive removal of tumor capsule that adhesed to brianstem or cranial nerve is avoided for preventing severe postoperative complication.

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