• 소성∙가공
• /
• 제17권1호
• /
• pp.13-18
• /
• 2008

Mg and Mg alloys are promising materials for light weight high strength applications. In this paper, grain refinement of pure Mg using severe plastic deformation was tried to enhance the mechanical properties of the hard-to-deform metallic material. The microstructure and the mechanical properties of Mg processed by equal channel angular pressing(ECAP) at various processing temperatures were investigated experimentally. ECAP with channel angle of $90^{\circ}$ and corner angle of $0^{\circ}$ was successful at $300^{\circ}C$ without fracture of the samples during the processing. The hardness of the ECAP processed Mg decreased with increasing ECAP processing temperature. The effect of temperature on the hardness and microstructure of the ECAP processed Mg were explained by the dislocation glide in the basal plane and non-basal slip systems and by the dynamic recrystallization and recovery.

• 대한족부족관절학회지
• /
• 제7권2호
• /
• pp.232-237
• /
• 2003

The purpose of this article is to evaluate and analyze diagnosis and the clinical result of avulsion fracture of navicular. Eight patients operated from Jan. 1991 to June 2002 were evaluated retrospectively. Clinical tolerability, AOFAS score, patient's satisfaction were evaluated. Preoperative AOFAS score is $59.88{\pm}10.90$. Postoperative AOFAS score is $94.75{\pm}6.11$. All patient satisfied result of operation, and 5 patient return to training wihin 3 month. Navicula avulsion fracure is relatively rare. The small dorsal bone triangular fragment is best seen in lateral view radiographs and bone scan and/or computed tomography help corfirm diagnosis. Operative treatment is the method of choice because of shorter recovery time. Simple excision is enough to get a good clincal outcome.

• 동력기계공학회지
• /
• 제10권1호
• /
• pp.60-64
• /
• 2006

Alumina ceramic for textile machinery was sintered and subjected to three-point bending. A semicircular surface crack was made on each sample. Crack-healing behavior was systematically studied, as a function of crack-healing temperature and crack size. The bending strength and fracture toughness of the crack-healed sample from $1200^{\circ}C\;to\;1400^{\circ}C$ were investigated. A statistical approach based on Weibull distribution was applied to the test data to evaluate the dispersion in the fracture toughness. Alumina ceramic for textile machinery have the ability to heal after cracking, from over $1300^{\circ}C$. The material can completely heal a $65{\mu}m$ diameter semielliptical crack. The fracture toughness could be explained by 2-parameter Weibull distribution.

• 혜화의학회지
• /
• 제23권1호
• /
• pp.157-166
• /
• 2014

상완골 간부 골절에 동반된 요골신경 손상을 가진 1명의 환자를 대상으로 "내경(內經)"의 독취양명치법(獨取陽明治法)에 따라 침구치료, 약침치료, 물리치료와 한약치료를 병행하였다. 손목관절의 하수 및 근력약화에 대한 치료성적으로 평가하기 위해 완관절의 운동범위와 능동저항검사를 통한 상대적인 지수를 평가하였으며, 요골신경마비로 인한 장악력의 약화정도는 악력측정기를 사용하여 평가하였다. 수지의 비증의 정도는 Numeric Rating Sclae(NRS) 사정법에 따라 평가하였다. 환자는 발병일로부터 약 6주째에 첫 회복징후를 보이기 시작하였으며, 발병이로부터 약 11.5주째에 가벼운 물건에 대한 집게운동이 가능하며 일상생활을 하는데에 큰 지장이 없는 수준으로 회복되었다. 이는 상완골 간부 골절이 동반된 요골신경손상의 자연회복시기보다 빠른 것으로, "내경(內經)"의 독취양명치법(獨取陽明治法)에 따른 한방치료요법이 상완골 골절에 동반된 요골신경손상의 치료에 효과가 있음을 알 수 있었다.

• 한국세라믹학회지
• /
• 제33권3호
• /
• pp.339-347
• /
• 1996

알루미나를 대상소재로 하여 국산 3종 및 일산 1종의 고순도 알루미나 제품을 구입하여 꺾임강도, 비커스 경도, 압자압입법 및 압입강도법에 의한 파괴인성 등의 기계적 물성을 평가하였다. 꺾임강도 및 와이블 계수는 제조회사에 따라 각각 약 300~400MPa, 5~15의 범위에서 큰 편차를 나타내었다. 압입하중 변화에 따른 경도시험시 탄성회복의 영향을 무시할 수 있는 임계하중은 약 9.8N이었으며, 압입하중 98N에서의 알루미나의 경도는 약 15GPa이었다. 파괴인성은 한 압입하중에서의 측정한 평균값으로 파괴인성을 구하는 것보다 압자압입법의 경우 압입하중과 균열길이, 압입강도법의 경우 압입하중과 꺾임강도와 관계식의 기울기로부터 각각 직선회기법으로 파괴인성을 구하는 것이 보다 신뢰성이 있으며, 알루미나의 파괴인성은 약 4 MPa·m1/2이었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제30권2호
• /
• pp.121-130
• /
• 2004

The purpose of this study was the long-term clinical and radiological evaluation of conservatively treated condylar fractures in children. This study was therefore undertaken to analyze the long-term effects of treating condylar fractures in children with conservative therapy in order to resolve the controversial question of whether complete remodeling occurs in this age or, if not, whether it is more likely to be associated with certain types of fracture or with other factors. This study was based on a series of 11 consecutive children and adolescents, aged between 3 and 15 years, with fractures of the condylar process who had been treated with conservative therapy at the Department of Oral & Maxillofacial surgery, Inha University Hospital, Inchon, Korea. All patients underwent a clinical investigation with special emphasis on Temporomandibular joint function and facial asymmetry. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of mandible. It consists of panoramic radiograph, PA & lateral cephalogram and 3-D CT. No patient described impaired temporomandibular joint(TMJ) function or pain on the affected side. 2 of 8 (25%) unilateral and 1 bilateral fractures show slight facial asymmetry. Despite apparently excellent recovery of function, there were marked remodeling changes evident on the CT scan. Such changes are not usually evident on panoramic radiograph. Radiologic investigation showed incomplete remodelling(54.5%) and asymmetry of the mandible (27.3%) in some patients. Conservative treatment of condyle fracture in children results in satisfactory long-term outcome of jaw function despite a relative high frequency of radiologically noted aberrations.

• 한국콘텐츠학회논문지
• /
• 제11권10호
• /
• pp.286-292
• /
• 2011

본 연구는 토끼골절모델에 미세전류자극(직류, 음극), 고전압 맥동직류 음극과 양극을 이용해 골절치유정도를 살펴보았다. 방사선 검사에 의한 육안 계측은 미세전류자극군이 고전압 맥동직류의 음극과 양극 통전군보다 골절치유척도 점수에서 통계학적으로 유의한 차이를 보였으나(p<0.05), 고전압 맥동직류 음극군과 양극군 사이에는 유의한 차이가 없었다(p>0.05). Hematoxylin-Eosin 염색과 Masson's trichrome 염색을 통한 병리조직표본 차이는 미세전류자극군에서 무층골의 증식이 다른 두 실험군보다 더 활발하게 관찰되었으며 연골내골화 과정도 다른 두 실험군에 비해 더 빠른 것으로 관찰되었다. Osteocalcin 면역조직화학 염색은 미세전류자극군이 골모세포, 골세포, 파골세포 및 골기질 내에서 면역양성반응이 다른 두 실험군보다 더 명확히 관찰되었다.

• 한방재활의학과학회지
• /
• 제30권1호
• /
• pp.13-29
• /
• 2020

Objectives This study was performed to decide the bone union effect of Hwaweo-jeon on tibia fractured mice. Methods In this study, laboratory experiments were implemented by the stage of in vitro and in vivo. In in vitro, MC3T3-E1 cells were treated with various concentration of Hwaweo-jeon extract (HWJ). To investigate effect of HWJ for osteoblast, relative mRNA expression of 5 substances (alkaline phosphatase [ALP], runt-related transcription factor 2 [Runx2], osteocalcin [OCN], osterix [OSX] and collagen type II alpha 1 chain [Col2a1]) was used as a marker of osteogenesis. In order to determine HWJ's effect for fracture healing, relative gene expression level of ALP, Runx2, OCN, OSX and Col2a1 were used to find out the influence to osteoblast. Furthermore, receptor activator of nuclear factor kappa-B ligand and osteoprotegerin relative mRNA expression were used to estimate the impact to osteoclast. Also, X-ray was used for the purpose of identifying bone union in tibia-fracture mouse model. Results In in vitro experiment, most part of relative mRNA expression were increased compared to control group. In in vivo and in vitro experiment, HWJ induced osteoblast activitation by verifying relative mRNA expression of 5 substances. And in vivo experiment, we can also identify that HWJ triggered osteoclast activation during early stage of tibia fracture. Furthermore, X-ray pictures show noticeable recovery of tibia fracture. Conclusions HWJ extract promotes bone union by facilitating the osteoblast. But, HWJ may occur liver & kidney toxicity over specific concentration. Therefore, when HWJ is applied to human body, doctors have to follow up the liver function test & renal function test of patient.

• 한국임상수의학회지
• /
• 제36권4호
• /
• pp.196-199
• /
• 2019

This study was conducted to evaluate and analyze fractures types, sites and surgical approach of wild birds in Korea. The study was conducted on data collected for fracture lesion sites, species, outcomes, surgical methods, treatments and medical records from wildlife centers in South Korea. All birds were subjected to clinical examination, followed by surgical invasion and post-operative care. Fractures were more common in adult non-raptor species (51.57%) as compared to raptors (48.43%). Of the 254 cases evaluated, maximum cases comprised ulnar fractures (29.70%), followed by radial (21.76%) and humeral fractures (17.35%). Treatment procedures at 340 fracture sites were maximally treated with figure-8 bandage (33.07%), external skeletal fixator-intramedullary pin (ESF+IM tie-in fixation) (20.86%), and other varied procedures. All birds were kept indoors till recovery. Treatment outcomes were dependent on the type of bone fractured and surgical method applied. Based on the surgical treatments and outcomes, birds were kept hospitalized, and released or euthanized. The findings of this study provide information for veterinarians regarding the fractures sites, basic database for the species and outcomes of fracture repair in wild birds.

• Korean Journal of Acupuncture
• /
• 제36권1호
• /
• pp.1-18
• /
• 2019

Objectives : The purpose of this study was to evaluate the effectiveness and safety of acupuncture treatment for recovery of patients with vertebral compression fracture(VCF). Methods : We searched ten English and Chinese and seven Korean database up to April 2018. Randomised controlled trials(RCTs), quasi-RCTs, non-radomised Controlled Trials(CCTs) were eligible. Quasi-RCTs and CCTs were assessed only for safety assessment. Pain and adverse events were primary outcome of this review. Quality of life, dysfunction, patient satisfaction, incidence of new vertebral compression fracture were regarded as secondary outcomes. The risk of bias was assessed by two independent authors using the Cochrane risk of bias tool. Level of evidence was tabulated using the GRADE methods. Results : Of 1656 screened, 15 RCTs, 1 quasi-RCT and 3 CCTs were included. Number of participants per study ranged from 45 to 135. Most of the studies had unclear or high risk of bias and considerable heterogeneity in terms of type of intervention, comparison and time-points for outcome measurement. Compared to usual care alone, acupuncture combined with usual care showed short-term favorable results for pain relief in patients with VCF(5 studies, n=252, MD -1.05 point on a 0 to 10 point scale, 95% CI -1.45 to -0.65, $I^2=74%$). Four studies reported mild and temporary adverse events, and no serious adverse events were reported. One study descriptively reported that acupuncture was effective for improving quality of life without providing numerical outcomes. There were no reports of patient satisfaction and incidence of new VCF. Conclusions : Level of evidence is very low for the effectiveness and safety of acupuncture for pain, harms and other clinical outcomes in patients with VCF. Included studies suffered from incomplete reporting, high or unclear risk of bias and substantial heterogeneity between studies. Future high-quality RCTs are needed to assess whether acupuncture is beneficial for recovery of patients with VCF.