• Journal of the Korean Arthroscopy Society
• /
• v.12 no.2
• /
• pp.118-124
• /
• 2008

Purpose: Recent development and advances in the arthroscopic surgical techniques for anterior cruciate ligament(ACL) reconstruction have led to the ideal location for more oblique anatomic point of the femur from 10 to 10:30 o'clock(in the right knee) and from 2 to 1:30 o'clock(in the left knee) in the frontal plane. This study was performed to compare the operative methods and the radiologic results of the femoral tunnels made through the tibial tunnel(trans-tibial approach) and the anteromedial portal. Materials and Methods: From January 2003 to May 2004, on hundred reconstructions of ACL were performed. Group I(the femoral tunnel made through the tibial tunnel) consisted of 50 cases and group I(the femoral tunnel made through the anteromedial portal) consisted of 50 cases. The operative methods and the radiographic results of the femoral tunnels were compared. Results: Femoral tunnel was made more easily at more oblique anatomic point in group II than in group I. In group II, better visual field was achieved at the angle of 100? flexion of the knee joint, the risks of the posterior cortical breakage and the tunnel-graft mismatching were reduced more, and the divergence of femoral interference screw from the radiograph decreased more than in group I(p<0.05). The angle between the femoral tunnel and the longitudinal axis of ACL increased in group II. Conclusion: Anteromedial portal technique was useful for femoral tunneling toward 10 to 10:30 o'clock(in the right knee) and 2 to 1:30 o'clock(in the left knee) in ACL reconstruction. Level of Evidence:Level III, case-control study.

• The Journal of Korean Academy of Prosthodontics
• /
• v.54 no.3
• /
• pp.291-297
• /
• 2016

Patients with $Sj{\ddot{o}}gren^{\prime}s$ syndrome usually suffer from teeth discoloration and attrition due to xerostomia. If the anterior teeth are badly worn, problems such as loss of anterior guidance, occlusal disharmony, and limited space for restoration may occur. However, ideal occlusion is obtained in both centric and eccentric relation by regaining the disocclusion of the posterior teeth through the anterior and lateral guidance using twin-stage method. In this case, rehabilitation was performed for a $Sj{\ddot{o}}gren^{\prime}s$ syndrome patient with maxillary and mandibular incisor's severe attrition and teeth discoloration by using twin-stage method.

• Smart Structures and Systems
• /
• v.14 no.6
• /
• pp.1173-1196
• /
• 2014

Real-time dynamic substructuring tests have been conducted on a cable-deck system. The cable is representative of a full scale cable for a cable-stayed bridge and it interacts with a deck, numerically modelled as a single-degree-of-freedom system. The purpose of exciting the inclined cable at the bottom is to identify its nonlinear dynamics and to mark the stability boundary of the semi-trivial solution. The latter physically corresponds to the point at which the cable starts to have an out-of-plane response when both input and previous response were in-plane. The numerical and the physical parts of the system interact through a transfer system, which is an actuator, and the input signal generated by the numerical model is assumed to interact instantaneously with the system. However, only an ideal system manifests a perfect correspondence between the desired signal and the applied signal. In fact, the transfer system introduces into the desired input signal a delay, which considerably affects the feedback force that, in turn, is processed to generate a new input. The effectiveness of the control algorithm is measured by using the synchronization technique, while the online adaptive forward prediction algorithm is used to compensate for the delay error, which is present in the performed tests. The response of the cable interacting with the deck has been experimentally observed, both in the presence of delay and when delay is compensated for, and it has been compared with the analytical model. The effects of the interface delay in real-time dynamic substructuring tests conducted on the cable-deck system are extensively discussed.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.26 no.2
• /
• pp.240-247
• /
• 1999

Primary anterior teeth requiring extensive restorative therapy due to caries, trauma or developmental defects can present a particularly challenging problem for the pediatric dentist. The ideal restorative technique would combine strength, durability esthetics and efficiency in placement. Couple these concerns with the technical difficulties of operating on children with behavior management problems, and the dentist is left with the difficult task of choosing from a variety of restorative options. Restorative modalities currently in use to treat primary anterior teeth include bonding with composite resin as in celluloid strip crowns, conventional stainless steel crowns, open-faced stainless steel crowns, commercially and chairside veneered stainless steel crowns and epoxy-coated stainless steel crowns. Each of these techniques presents technical, functional or esthetic compromises that complicate their efficient and effective usage. This is a report of the results obtained at the Department of Pediatric Dentistry, College of Dentistry Seoul National University, through the use of these various methods of treating primary anterior teeth.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.19 no.6
• /
• pp.323-341
• /
• 2019

Background: Local anesthetics alone or in combination with adjuncts, such as oral medications, have routinely been used for pain control during endodontic treatment. The best clinical choice amongst the vast numbers of agents and techniques available for pain control for irreversible pulpitis is unclear. This network meta-analysis combined the available evidence on agents and techniques for pulpal anesthesia in the maxilla and mandible, in order to identify the best amongst these approaches statistically, as a basis for future clinical trials. Methods: Randomized trials in MEDLINE, DARE, and COCHRANE databases were screened based on inclusion criteria and data were extracted. Heterogeneity was assessed and odds ratios were used to estimate effects. Inconsistencies between direct and indirect pooled estimates were evaluated by H-statistics. The Grading of Recommendation, Assessment, Development, and Evaluation working group approach was used to assess evidence quality. Results: Sixty-two studies (nine studies in the maxilla and 53 studies in the mandible) were included in the meta-analysis. Increased mandibular pulpal anesthesia success was observed on premedication with aceclofenac + paracetamol or supplemental 4% articaine buccal infiltration or ibuprofen+paracetamol premedication, all the above mentioned with 2% lignocaine inferior alveolar nerve block (IANB). No significant difference was noted for any of the agents investigated in terms of the success rate of maxillary pulpal anesthesia. Conclusion: Direct and indirect comparisons indicated that some combinations of IANB with premedication and/or supplemental infiltration had a greater chance of producing successful mandibular pulpal anesthesia. No ideal technique for maxillary anesthesia emerged. Randomized clinical trials with increased sample size may be needed to provide more conclusive data. Our findings suggest that further high-quality studies are required in order to provide definitive direction to clinicians regarding the best agents and techniques to use for mandibular and maxillary anesthesia for irreversible pulpitis.

• Journal of Biosystems Engineering
• /
• v.41 no.1
• /
• pp.60-65
• /
• 2016

Purpose: The necessity for precise manipulation of bioparticles has greatly increased in the fields of bioscience, biomedical, and environmental monitoring. Dielectrophoresis (DEP) is considered to be an ideal technique to manipulate bioparticles. The objective of this study is to develop a DEP microfluidic device that can trap fluorescent beads, which mimic bioparticles, at the low voltage and frequency of the sinusoidal signal supplied to the microfluidic device. Methods: A DEP microfluidic device, which is composed of polydimethylsiloxane (PDMS) channels and interdigitated electrode networks, is fabricated to trap fluorescent beads. The geometry of the interdigitated electrodes is determined through computational simulation. To determine the optimum voltage and frequency of the sinusoidal signal supplied to the device, the experiments of trapping beads are conducted at various combinations of voltage and frequency. The performance of the DEP microfluidic device is evaluated by investigating the correlation between fluorescent intensities and bead concentrations. Results: The optimum ratio of the widths between the negative and positive electrodes was 1:4 ($20:80{\mu}m$) at a gap of $20{\mu}m$ between the two electrodes. The DEP electrode networks were fabricated based on this geometry and used for the bead trapping experiments. The optimum voltage and frequency of the supplied signal for trapping fluorescent beads were 15 V and 5 kHz, respectively. The fluorescent intensity of the trapped beads increased linearly as the bead concentration increased. The coefficient of determination ($R^2$) between the fluorescent intensity and the bead concentration was 0.989. Conclusions: It is concluded that the microfluidic device developed in this study is promising for trapping bioparticles, such as a cell or virus, if they are conjugated to beads, and their concentration is quantified.

• Journal of Korean Society of Steel Construction
• /
• v.14 no.6
• /
• pp.783-791
• /
• 2002

An improved formulation for multi-objective optimization was proposed. This formulation was applied to steel seismic loads. The multi-objective optimization problem was formulated with minimum structural weight, maximum strstability. The global criterion method was employed to find a rational solution closest to the ideal solution for the optimization problem using standard steel profile, To efficiently solve the optimization problem, the decomposition meth both system-level and element-level was used. In addition, various techniques including efficient reanalysis technique intermediate variables and sensitivity analysis using an automatic differentiation(AD) were incorporated. Moreover the reamong section properties fitted to the section profile used in order to link the system level and the element level. From numerical investigation, it could be stated that the proposed method will lead to the more rational design compared with one.

• Journal of Chest Surgery
• /
• v.9 no.2
• /
• pp.207-214
• /
• 1976

Operations for cardiac valvular disease has been progressed in various ways. Since 1949 when Lord Russel operated mitral stenosis by closed technique at Johns Hopkins Hospital then much progress has been achieved and that nowadays severely diseased cardiac valve has been replaced by prosthetic valve, which is almost ideal in hemodynamic aspect, but still it has many problems such as thromboembolism, destruction of red blood cell, pressure gradient, and disturbance of left ventricular function, so in case of delicate situations, valve replacement should be decided carefully. Besides prosthetic valve, there are some kinds of reconstructive procedures and these have been resulted in better prognosis than prosthetic valve replacement in selected cases. So, authors have reviewed 61 Cases of cardiac patients who have been operated reconstructive valvular surgery by cardiopulmonary bypass, at Yonsei University, from Jan. 1963 to Mar. 1976. Out of 61 cases, 9 patients were replaced by prosthetic valve and rest of the patients were operated upon in various reconstructive procedures such as commissurotomy, valvotomy, valvuloplasty, and annuloplasty. Twenty cases of congenital heart diseases with valvular lesion, which had been operated for valvular lesion were also included in this statistics. Out of 9 cases of prosthetic valvular replacement five cases of prosthetic valvular replacement was done combined with other reconstructive procedures after attempted valvuloplasty. Comparative prognosis of both procedures are somewhat variable by reporters, average 19% of mortality after reconstructive surgery and 38% of mortality after prosthetic valve replacement in long term results. Most common cause of death in postoperative period was low output syndrome in both cases. It seems that good preoperative evaluation and proper reconstructive surgery will afford good prognosis in selected cardiac valvular diseased patient.

• Journal of Nutrition and Health
• /
• v.26 no.3
• /
• pp.299-312
• /
• 1993

Anthropometry, computed tomography(CT) at the umbilical level, nutrient intake, blood pressure, serum levels of lipids and lipoproteins and response of glucose, c-peptide, insulin, and free fatty acid(FFA) during oral glucose tolerance test(OGTT) were estimated on 11 normal-weight controls and 35 overweight and obese middle-agd men. The areas of total abdominal, subcutaneous and visceral were determined by CT scanning technique. Total abdominal fat area correlated the most significantly with the levels of serum lipids, lipoproteins and insulin among several obese indices. Compared with normal-weight controls, overweight and obese men with abdominal fat lower than 29000$\textrm{mm}^2$ showed an increase in waist-hip ratio, areas of total abdominal(35%), visceral and subcutaneous fat and C-peptide response area during OGTT, though age, percent ideal body weight, body mass index, % body fat, and all biochemical indices except C-peptide response area were not different between two groups. Overweight and obese men with abdominal fat greater than 29000$\textrm{mm}^2$ showed a higher values in total abdominal fat(85%), serum levels of triglyceride, total-and LDL-cholesterol, the ratio of LDL-to HDL-cholesterol, and response areas of FFA, insulin and C-peptide during OGTT than normal-weight controls. Overweight and obese men with great abdominal fat showed an increase in alcohol ingestion and percent calorie intake per total energy expenditure, compared with normal-weight controls. Our results indicate that obesity and a certain level of total abdominal fat accumulation is required to observe abnormal levels of serum lipids, lipoproteins and insulin in Korean middle-aged men. In addition, increased alcohol and calorie intake and decreased physical activity could partly explain total abdominal fat accumulation in men.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.7B
• /
• pp.1351-1360
• /
• 1999

In frequency selective channels, conventional PN code acquisition schemes are not ideal candidates. This is because they are primarily designed for the AWGN channel. In this paper, a direct-sequence spread-spectrum(DSSS) PN code acquisition system based on digital matched filtering (DMF) with automatic threshold control(ATC) algorithm is presented and analyzed with regards to probability of detection and probability of false alarm. These two important probabilities, the probability of detection ($P_D$) and the probability of false alarm ($P_{FA}$) are derived and analyzed in considering Doppler shift, sampling rate, mean acquisition time, and PN chip rate in frequency selective Rayleigh fading channel when using serial-search method as detection technique. From computer simulation results of a DMF acquisition system model, it is shown that the performance of the acquisition system using ATC algorithm is better than that of constant threshold system.