• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.604-613
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• 2002

Generation characteristics of electrospray droplets for highly viscous liquid have been investigated by measuring size distributions of droplets emitted from the Taylor cone using glycerol solutions with various conductivities. Because of very small volatility of glycerol, droplet sizes can be measured by an aerodynamic size spectrometer (TSI Aerosizer DSP) with negligible evaporation of droplets. For highly conducting and viscous liquid, the sizes of the droplets electrosprayed from the Taylor cone are found to be relatively insensitive to applied voltages and the electrosprays assisted by the corona discharge call produce monodisperse droplets as long as the corona intensity is not too high. Near the minimum flow rate where a liquid cone is stable, the spray tends to consist of a one -peak monodisperse distribution of drop lets. However, at high flow rates, the spray bifurcates into bimodal distributions, which are consistent with the result of the previous study for less viscous liquids than our liquids. For liquid flow rates (Q) below 1 nl/s, the measured droplet diameters by the aerosizer are in the range of 0.30 to 1.2 ${\mu}{\textrm}{m}$ for the glycerol solutions. The diameters of monodisperse droplets scale approximately with $r^*=Q_$\tau$(Q$\tau$){^1/3}$ where $r^*$ is a characteristic length and $\tau$is the electrical relaxation time of the fluid. However, when compared with several represe ntative scaling laws, the droplet diameters are two to six factors greater than those predicted by the scaling laws. This may be closely related to the combined effect of the much higher viscosity and the electrical charge on the jet breakup of glycerol so solution.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.134-137
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• 2007

The temporal evolution of wake behind a circular cylinder oscillating rotationally with a relatively high forcing frequency has been investigated experimentally using a dynamic PIV technique. Experiments were carried out with varying the frequency ratio $F_R\;(=f_f/f_n)$ in the range from 0.0 (stationary) to 1.6 at oscillation amplitude of ${\theta}_A=30^{\circ}$ and Reynolds number of $Re=4.14{\times}10^3$. Depending on the forcing condition ($F_R$), the flow was divided into three regimes; non-lock-on ($F_R=0.4$), transition ($F_R=0.8$, 1.6) and lock-on regimes ($F_R=1.0$) with markedly different flow structure in the near-wake region behind the cylinder. When the frequency ratio was less than 1.0 ($F_R{\le}1.0$), the rotational oscillatory motion of the cylinder decreased the length of the vortex formation region and enhanced the mutual interaction between large-scale vortices across the wake centerline. The entrainment of ambient fluid seemed to play an important role in controlling the near-wake flow and shear-layer instability. However, the flow characteristics changed markedly beyond the lock-on flow regime ($F_R=1.0$) due to high-frequency forcing. At $F_R=1.6$, the mutual interactions between the vortices shed from both sides of the cylinder were not so strong. Thereby, the flow entrainment and momentum transfer into the wake center region were reduced. In addition, the size of the large-scale vortices decreased since the lateral extent of the wake was suppressed.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.121-124
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• 2011

Hill-Sachs lesion is the most common lesion in shoulder dislocation patient and it represented by postero-lateral bony defect of humerus. The lesion could be found in patients who dislocate shoulder joint first time, and it is reported that Hill-Sachs lesion proportionally increases as dislocation does. The location and presence of Hill-Sachs lesion play significant roles in shoulder instability. Authors experienced a double Hill-Sachs lesion in a recurrent anterior shoulder dislocation patient, and thereby report the case with a review of the literature.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.34-39
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• 2016

Objective: Hip abductors play a role in providing stability and movement to the lower limbs. The purpose of this study was to examine the effects of hip abductor fatigue on static balance and gait in the general population. Design: One group pre-test post-test design. Methods: Thirteen university students in their twenties volunteered for the study and had underwent a functional assessment. To induce fatigue, the subjects were instructed to raise their dominant lower extremity up against a load of 50% of 1 repetition maximum while producing hip abduction in a side-lying position. Subjects were instructed to maintain an abduction speed of 30 repetitions per minute to induce fatigue. Muscle fatigue was considered to be established when subjects were unable to perform hip abduction three consecutive times along with the metronome. A post-test of balance and gait was performed immediately in order to prevent fatigue recovery. The center of pressure (COP) distance area was measured using the Zebris FDM-S Multifunction Force measuring plate. Gait performance was analyzed using the GAITRite. Results: The COP distance was increased after fatigue was induced. There was a significant increase in the standard deviation of the medio-lateral and antero-posteror distance (p<0.05). Although there was no significant difference in gait parameters, there was a significant decrease in single support time after fatigue was induced (p<0.05). Conclusions: There was an increase in static balance instability and a significant decrease in single support time during gait due to hip abductor muscle fatigue.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.485-490
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• 2006

Purpose: As the traditional treatment of the Wassel's type I or II of bifid thumb, Bilhaut-Cloquet, has always been the standard method despite several disadvantages such as tearing of the finger nail, injuries of the growth plate, joint instability, and long visible scarring. To overcome these drawbacks, we applied a modified Bilhaut-Cloquet Method. Methods: The subjects used for the this study were 10 of 20 patients evaluated. The patients underwent modified methods under every type of Wassel's classification. We designed a central wedge Zig-Zag incision and removed the nail and bony tissues in the remaining digit, but not soft tissue if possible, and transferred the ligaments, tendons, and soft tissue to the remaining thumb from the extra digit. We evaluated the patients' lack of extension, the total ROM of the MP and IP joints, the ROM of IP joints, and the lateral deviations of the reconstructed thumb. Results: The results were encouraging, with all patients showing a good functional and aesthetic outcome. Conclusion: The modified method proved a very effective procedure in the treatment of bifid thumb in all types, especially types I or II.

• Journal of the Korean Arthroscopy Society
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• v.7 no.1
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• pp.92-95
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• 2003

A 34-year-old man with ACL total rupture due to slip down injury, had received ACL reconstruction using autogenous hamstrings tendon with cross-pin femoral fixation. Postoperative course was as usual. But postoperative 3 months later, he complained posterolateral knee pain, recurrent effusion and mild instability. He was managed repeatitive aspiration and nonsteroid antiinflammatory drugs but was failed to relieve symptoms & signs. In CT scans, perforation of posteromedial femoral cortex of lateral femoral condyle was found. In second look arthroscopy, two pieces of broken femoral cross pin were found in between tibiofemoral Joint which was badly injured cartilage. We considered malposition of pins was the main cause of failure. We propose that femoral tunnel must be made more acute angle and femoral cross-pin guide must be positioned more external rotation 10-20 degree than transepicondylar axis made confirm the cross-pin tunnel position in order to avoid posterior cortex perforation and early failure.

• Physical Therapy Korea
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• v.31 no.1
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• pp.79-88
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• 2024

Background: The abdominal drawing-in maneuver (ADIM), a method of lumbar stabilization training, is an effective neuromuscular intervention for lumbar instability associated with low back pain (LBP). Objects: The purpose of this study was to compare the effect of a 2-week period of the ADIM and tensor fasciae latae-iliotibial band (TFL-ITB) self-stretching on lumbopelvic rotation angle, lumbopelvic rotation movement onset, TFL-ITB length, and pain intensity during active prone hip lateral rotation. Methods: Twenty-two subjects with lumbar extension rotation syndrome accompanying shortened TFL-ITB (16 males and 6 females) were recruited for this study. The subjects were instructed how to perform ADIM training or ADIM training plus TFL-ITB self-stretching program at home for a 2-week period. A 3-dimensional ultrasonic motion analysis system was used to measure the lumbopelvic rotation angle and lumbopelvic rotation movement onset. An independent t-test was used to determine between-group differences for each outcome measure (lumbopelvic rotation angle, lumbopelvic rotation movement onset, TFL-ITB length, and pain intensity). Results: The results showed that ADIM training plus TFL-ITB self-stretching decreased the lumbopelvic rotation angle, delayed the lumbopelvic rotation movement onset, and elongated the TFL-ITB significantly more than did ADIM training alone. Pain intensity was lower in the ADIM training plus TFL-ITB self-stretching group than the ADIM training alone group; however, the difference was not significant. Conclusion: ADIM training plus TFL-ITB self-stretching performed for a 2-week period at home may be an effective treatment for modifying lumbopelvic motion and reducing LBP.

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.69-73
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• 2001

Purpose : To evaluate the clinical results and widening of bony tunnel after anterior cruciate ligament(ACL) reconstruction using hamstring tendon with Ligament Anchor(LA) screw, which is newly designed fur fixation of graft into femur. Materials and Methods : Fifty eight patients who were followed up at least more than 2 years after ACL reconstruction with four strands of Hamstring tendon were included in this study. The graft was fixed with LA screw at femoral tunnel and with bioabsorbable interference screw at tibial tunnel. The average period of follow-up was 28 months. The clinical results such as physical examination and Lysholm knee score and radiological results. widening of bony tunnel and instrumented anterior laxity test with $Telos^{\circledR}$(Telos stress device; Austin & Associates, Inc., Polston, US) were evaluated. Results . The Lysholm knee score was 60.0 in average preoperatively and improved to 94.0 in average at follow up. On the Lachman test, there were mild(+) instability in 16 cases, moderate(++) in 24, severe(+++) in 18 preoperatively. 50 cases were converted to negative and 8 to mild instability at follow up. On instrumented anterior laxity test with $Telos^{\circledR}$, side to side difference in 20 lb was 12.9mm in average preoperatively, and was decreased to 3.1mm in average follow-up. The femoral tunnel was widened from 10.6mm postoperatively to 12.7mm$(21.1\%)$ at follow up on antero-posterior plane and from 10.7mm to 12.4mm$(16.5\%)$ on lateral plane. Tibial tunnels was also widened from 9.8mm to 11.8mm$(20.7\%)$ on antero-posterior plane and from 9.9mm to 11.7mm$(18.9\%)$ in lateral plane. Conclusion : ACL reconstruction with hamstring tendon and LA screw was one of the choice of grafts and fixatives in restoring knee stability and in improving clinical results with little complications such as excessive widening of bony tunnel.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.47-53
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• 2011

Purpose: As the number of the anterior cruciate ligament (ACL) reconstruction has increased, the incidence of revision of ACL reconstruction due to reconstruction failure has been also increased. Therefore, authors analyzed the reason of the failure of ACL reconstruction and the clinical result of the ACL revision. Materials and methods: From February 1998 to July 2010, we selected 36 cases which was followed at least 12months after the ACL reconstruction failure. Duration from reconstruction to revision, the average duration was 60 months (5~334) and on first reconstruction, we used allograft on 23 cases (63.9%) and autograft on 13 cases (36.1%). For the main symptom of ACL reconstruction failure, instability was the most common symptom, and 35 cases (97.5%) were undergone only one reconstruction and 1case (2.5%) was undergone two reconstruction. Clinical results were evaluated by Lysholm knee joint score, pivot shift test, and Telos device. Results: Average follow-up duration of the patients was 21 months (12~40), and the reason for the ACL reconstruction failure, trauma was most common by 19 cases (52.8%), malposition of the femoral tunnel was 13 cases (36.1%), malposition of the tibia tunnel was 1case (2.8%), and failure of osteointegration was 3 cases (8.4%). On performing the ACL revision, we used allograft on 34 cases (94%) and autograft on 2 cases (6%), and 21 cases accompanied injury of the meniscus (medial meniscus 14 cases, lateral meniscus 7 cases). Lysholm knee joint score was improved from 66.5 points, preoperatively to 92 points on last follow-up (p<0.01). In most cases, patients were satisfied (92%) with the operation results. Tegner activity score was also improved from 2.0 points preoperatively to 6.2 points on the last follow-up. On Lachman and pivot sift test, 33 cases and 30 cases were improved to grade I respectively, and on stability test using Telos device, the bilateral difference was improved from mean 15.5 mm preoperatively to 4.5 mm on the last follow-up. Conclusion: After 1 year follow-up, Revision of ACL had a little anterior instability but it showed satisfactory result on clinical result and patient's subjective satisfaction.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.2 no.2
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• pp.17-32
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• 2007

Objectives : The lumbosacral joint is unstable area from an anatomical viewpoint, while it is also a very mobile area in ordinary life, so that clinically major causes of low back pain originate in this joint. The purpose of this study is to assess the difference of the Ferguson's angles, Lumbar gravity lines, Lumbar lordotic angles among Herniated of Intervertebral Disc(HIVD) patients. Methods : We analyzed the lateral view of lumbar spine checked at erect position on 88 patients who had been diagnosed as HIVD by Magnetic Resonance Imaging(MRI). We investigated the Ferguson's angle, Lumbar gravity line, Lumbar lordotic angle on X-ray film. Results and Conclusions : In the acute lumbago group the Ferguson's angle had a tendency to decrease, while in the chronic group it had a tendency to increase. In the acute lumbago group the Lumbar gravity line fell in front of the normal range(sacrum), while in the chronic group it fell behind the normal range(sacrum). In the acute lumbago group the Lumbar lordotic angle usually decreased, while in the chronic group it increased. The Ferguson's angle and the Lumbar gravity line, the Ferguson's angle and the Lumbar lordotic angle, the Lumbar gravity line and Lumbar lordotic angle each had a positive realtionship. The Ferguson's angle, the Lumbar gravity line and the Lumbar lordotic angle was less influenced by the level of HIVD and was more influenced by how long the patient had the pain. The correlationship between each factor was less in the chronic lumbago group than the acute group. In the chronic lumbago group the instability of the lumbosacral joint increased, while in the acute group the compression of the weight on the sacrum increased.