• The Journal of Korean Orthopaedic Ultrasound Society
• /
• v.4 no.2
• /
• pp.111-122
• /
• 2011

Platelet rich plasma (PRP) has been widely used nowadays for several common orthopaedic-related sports medicine conditions with the theoretical basis that PRP supplies numerous autologous growth factors from concentrated platelets needed to promote the healing process of injured tissue. Even though there are many basic sciences, animal studies and some clinical studies regarding PRP injections for musculoskeletal injuries which suggested good results, it is difficult to compare these various studies due to marked methodological differences such as PRP preparation method, the timing, volume and number of injection, and the outcome measurement tool. In addition, many studies have no control groups or a limited sample size, and there are few prospective randomized controlled trials assessing the efficacy of PRP injections. Therefore, well designed high-quality randomized studies are required to confirm the preliminary results until now and provide scientific evidence to support its use, and the paucity of scientific clinical evidence suggest that the administration of PRP on humans for musculoskeletal injuries should be performed with caution.

• 대한예방의학회:학술대회논문집
• /
• 2005.10a
• /
• pp.376-376
• /
• 2005

• 대한예방의학회:학술대회논문집
• /
• 2002.10a
• /
• pp.528-529
• /
• 2002

• The Journal of the Korean dental association
• /
• v.42 no.12 s.427
• /
• pp.873-881
• /
• 2004

• 대한예방의학회:학술대회논문집
• /
• 2000.10a
• /
• pp.276-277
• /
• 2000

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.1
• /
• pp.28-35
• /
• 2002

In cavity flow, the rectangular step generates so strong sound that many researchers have investigated method to suppress the nois during interaction between vortical flow and rectangular forward step. In this study the flow noise from the vortex motion in two-dimentional low Mach number flow past a forward step with various chamfering angle is calculated numerically. Inviscid incompressible discrete vortex model and matched asymptotic expansion(MAE) theory are applied to obtain the inner flow field and the outer noise field. Both source acoustic pressure and sound intensity are obtained with various chamfering height, chamfering angle and initial vortex position. The pressure amplitude is most suppressed when the chamfering angle is between $15^{\circ}C$ and $30^{\circC}$ at the chamfering length of 30% of the step height.

• The korean journal of orthodontics
• /
• v.35 no.5 s.112
• /
• pp.381-387
• /
• 2005

The aim of this study was to compare the clinical performance of 4 types of orthodontic wires, indicated for initial tooth alignment: stainless steel, multistranded steel, superelastic and thermoactivated nickel-titanium. A prospective randomized clinical trial was conducted on a sample of 45 patients, at the Dental School of the State University of Rio do Janeiro, Brazil. Fixed appliances were fitted and study casts were obtained from each patient. Randomly, the wires were allocated as follows: 26 dental arches for superelastic NiTi wires, 22 for stainless steel, 22 for multistranded and 20 for thermoactivated archwires. After 8 weeks, the archwires were removed and impressions for study casts were taken again. Using a 3D digitization technique of defined anatomical points on the study cast crowns, a Dental Irregularity Index (DII) was created for each study cast. The difference between DII before and after the archwire insertion expressed the aligning effect of the wires. ANOVA tests were employed to evaluate the anatomical point approximation (positive DII) and separation (negative DII), for each area of the dental arches: upper and lower whole arch and anterior arch. Results showed no significant difference between the different archwires.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1999.04a
• /
• pp.15-15
• /
• 1999

2차 유동 분사에 의한 추력 방향 제어 방법은 복잡한 기계적 작동장치와 이에 따른 무게의 증가를 배제할 수 있다. 본 연구에서는 유동 해석을 통하여 2차원 및 3차원 초음속 수축-팽창 노즐 유동에 2차 유동을 분사하여, 2차 유동의 분사 위치, 분사 유량 및 분사 각도 등이 추력의 방향 및 크기에 미치는 영향을 밝혀 추력 방향 제어를 위한 최적의 2차 분사 조건을 제시하였다. 유동 해석 결과 2차 유동의 분사 위치는 생성된 경가 충격파가 노즐 출구까지 분포되는 지점이 최대 전향각과 횡추력을 가지는 분사위치임을 알 수 있었고, 분사 각도는 주 유동의 역방향으로 분사하는 것이 수직방향으로 분사하는 것보다 더 큰 전향각을 얻을 수 있었다. 또한 2차원의 경우보다 3차원 유동에서 큰 전향각이 생김을 알 수 있었다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.6
• /
• pp.173-186
• /
• 2003

Distributed Denial-of-Service(DDoS) attack prevent users from accessing services on the target network by spoofing its origin source address with a large volume of traffic. The objective of IP Traceback is to determine the real attack sources, as well as the full path taken by the attack packets. Existing IP Traceback methods can be categorized as proactive or reactive dating. Proactive tracing(such as packet marking and messaging) prepares information for tracing when packets are in transit. Reactive tracing starts tracing after an attack is detected. In this paper, we propose a 'advanced ICW Traceback' mechanism, which is based on the modified pushback system with secure router mechanism. Proposed mechanism can detect and control DDoS traffic on router and can generate ICMP Traceback message for reconstructing origin attack source, by which we can diminish network overload and enhance Traceback performance.

• Child Health Nursing Research
• /
• v.24 no.1
• /
• pp.58-67
• /
• 2018

Purpose: This prospective study aimed to examine the development of premature infants at 12 and 24 months and to explore the factors related to their development. Methods: Of the 80 premature infants who were recruited, 52 participants at 12 months and 31 participants at 24 months were included in this study. The development of the infants was examined using the Korean Bayley scale of infant development-II. Postnatal depression, husband's support, social support, mother-infant attachment, and the home environment were assessed using self-report questionnaires completed by the mothers and through the researcher's observations. Results: There was significant difference between normal and delay group at psychomotor development at 12 months depending on social support at 6 months (t=2.03, p=.049). Mother-infant attachment at 6 months (r=.71, p<.001), 12 months (r=.37, p=.043), and 24 months (r=.40, p=.026), as well as social support (r=.38, p=.034) and the home environment (r=.41, p=.022) at 24 months, were correlated to mental development at 24 months. There was a significant positive correlation between mother-infant attachment at 6 months and psychomotor development at 24 months (r=.40, p=.046). Conclusion: To reduce the risk of developmental delay and to promote healthy development in premature infants, early nursing interventions targeting mother-infant attachment, the home environment, and the mother's social support structure are needed.