• Geomechanics and Engineering
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• v.8 no.6
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• pp.757-767
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• 2015

Rock mass is an important engineering material. In hydropower engineering, rock mass of bank slope controlled the stability of an arch dam. However, mechanical characteristics of the rock mass are not only affected by lithology, but also joints. On the basis of field geological survey, this paper built rock mass material containing parallel concentrated joints with different dip angle, different number under different stress conditions by PFC (Particle Flow Code) numerical simulation. Next, we analyzed mechanical property and fracture features of this rock mass. The following achievements have been obtained through this research. (1) When dip angle of joints is $15^{\circ}$ and $30^{\circ}$, with the increase of joints number, peak strength of rock mass has not changed much. But when dip angle increase to $45^{\circ}$, especially increase to $60^{\circ}$ and $75^{\circ}$, peak strength of rock mass decreased obviously with the increase of joints number. (2) With the increase of confining stress, peak strengths of all rock mass have different degree of improvement, especially the rock mass with dip angle of $75^{\circ}$. (3) Under the condition of no confining stress, dip angle of joints is low and joint number is small, existence of joints has little influence on fracture mode of rock mass, but when joints number increase to 5, tensile deformation firstly happened at joints zone and further resulted in tension fracture of the whole rock mass. When dip angle of joints increases to $45^{\circ}$, fracture presented as shear along joints, and with increase of joints number, strength of rock mass is weakened caused by shear-tension fracture zone along joints. When dip angle of joints increases to $60^{\circ}$ and $75^{\circ}$, deformation and fracture model presented as tension fracture zone along concentrated joints. (4) Influence of increase of confining stress on fracture modes is to weaken joints' control function and to reduce the width of fracture zone. Furthermore, increase of confining stress translated deformation mode from tension to shear.

• Journal of muscle and joint health
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• v.19 no.3
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• pp.282-293
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• 2012

Purpose: The study aimed to examine the effects of Tai Chi fall prevention program on risk factors for fall, fear of falling, and quality of life among elderly women living in the community. Methods: A quasi-experimental pretest-posttest design with non-equivalent control group was used. Sixty participants were recruited from 4 senior citizen centers in a city. The 1-hour Tai Chi fall prevention program was provided three times a week for 6 months to the experimental group. Risk factors for fall including fracture risk and bone mineral density, fear of falling, and quality of life were measured at the baseline and at 6 months. Results: Participants were 75 years old in average. At the completion of 6 month program, the experimental group showed lower fracture risks, less fear of falling, and higher scores in several domains of quality of life than the control group, after controlling for the pretest scores, fall experience, and regular exercise habit. Conclusion: The Tai Chi fall prevention program was safely applied to elderly women with improvement in fracture risk, fear of falling, and several domains of quality of life. Future study is necessary to confirm the longer effect of the Tai Chi program for the prevention of fall episodes.

• Journal of muscle and joint health
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• v.19 no.2
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• pp.131-141
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• 2012

Purpose: The purpose of this study was to test the change of study variables (knowledge, efficacy, and fatigue) related to using orthosis and fear of falling in fracture patients wearing the leg orthosis after fall prevention education in terms of educational method and frequency. Methods: Participants were 87 fracture patients wearing the leg orthosis. Experimental I group (n=30) and experimental II group (n=27) received the fall prevention education once and three times respectively with leaflets. Experimental III group (n=30) received video training once. Results: The level of the subjects' knowledge was significantly increased in experimental I and II groups rather than in experimental III group. In case of experimental I and experimental II group, fear of falling was decreased when compared to experimental III group. However, there were no significant changes in efficacy and fatigue related to using orthosis among three groups. Conclusion: The fall prevention education using leaflets was more effective than video training method. Only one education with leaflets was effective enough. Therefore, it is recommended that the education with leaflets or pamphlets should be developed systematically according to the characteristics of fracture patients wearing the leg orthosis.

• Knee surgery & related research
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• v.30 no.4
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• pp.303-310
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• 2018

Purpose: The purpose of this study was to investigate whether surgical experience could improve surgical competency in medial open wedge high tibial osteotomy (MOWHTO). Materials and Methods: One hundred consecutive cases of MOWHTO were performed with preoperative planning using the Miniaci method. Surgical errors were defined as under- or overcorrection, excessive posterior slope change, or the presence of a lateral hinge fracture. Each of these treatment failures was separately evaluated using the cumulative summation test for learning curve (LC-CUSUM). Results: The LC-CUSUM showed competency in prevention of undercorrection, excessive posterior slope change, and lateral hinge fracture after 27, 47, and 42 procedures, respectively. However, the LC-CUSUM did not signal achievement of competency in prevention of overcorrection after 100 procedures. Furthermore, the failure rate for overcorrection showed an increasing tendency as surgical experience increased. Conclusions: Surgical experience may improve the surgeon's competency in prevention of undercorrection, excessive posterior slope change, and lateral hinge fracture. However, it may not help reduce the incidence of overcorrection even after performance of 100 cases of MOWHTO over a period of 6 years.

• Journal of radiological science and technology
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• v.25 no.1
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• pp.49-53
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• 2002

The femoral fracture is the most serious problem of old ages haying osteoporotic fractures. First of all, prevention to reduce the incidence of hip fracture and to identify the risk factor is essential subject. The purpose of this study is to investigate which geometric parameters of proximal femur are related to the hip fracture risk in old ages. Author analyzed the bone density and bone content of over 60 years old women who had suffered hip fracture (n=60) and non fracture groups (n=60). Author concluded that geometric measurements of proximal femoral part made on dual energy x-ray absorptiometry can predict hip fracture independently of bone mineral density.

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1417-1422
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• 2001

Since fracture surface presents clear evidence to describe the circumstances of material failure event, analysis of fracture surface should provide plenty of useful information for failure prevention. Thus if we extract proper information from the fracture surface, the safety evaluation, for plant component could be more accurate. In general, the chaotic morphology of fracture surface is determined by the degree of material degradation as well as by other factors such as type of load, geometry of specimen, notch condition, microstructure of material and environment. In this research, we developed a fractal analysis technology for the fracture surface of aged turbine rotor steel based on the slit-island technique using an image analyzer. Moreover the correlation between the fractal dimension and the aging time was studied.

• The Journal of the Korean dental association
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• v.52 no.2
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• pp.60-68
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• 2014

Nickel-Titanium(NiTi) rotary instruments have brought a big step toward "efficient" practice of endodontic procedure. The rotary files help clinicians to reduce their working time and also increase the clinical success rate with minimal procedural errors by stainless steel instruments. In spite of these advantages, NiTi instruments still have a few drawbacks including unpredictable fatigue fracture. Clinicians may reduce the potential risk of instruments fracture by following some clinical guidelines for rotary instruments. In some clinical cases of instruments fracture, we may try to remove the instruments' fragments or bypass the fragment to reach the apical canal. In some limited cases, the fractured instruments' fragments would not jeopardize the clinical prognosis of root canal treatment. However, it is impossible to be overemphasized that the fragment removal is more difficult than the prevention of fracture. Clinicians need to understand the fracture mechanisms and, in clinic, need to discard the used instruments timely.

• Journal of Korean Academy of Nursing
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• v.31 no.2
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• pp.194-205
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• 2001

The purpose of the study was to identify the effect of structured patients education had on prevention of osteoporosis, with fracture and the resulting of life style changes in patients. In this study, a non equivalent control group pre and a post test design was employed. Data were collected through an interview process using questionnaires from April to December of 1999. The subjects, consisting of 59 patients with fractures and over 40 years of age, were diagnosed in K University Hospital. This study tested the patients knowledge at three times. The times were before the program 2 weeks into the program, and 6 months after education program. Life style change related to prevention of osteoporosis was shown twice (before and 6 months after the education program) in the experimental group, and control group went without it. The instruments used for this study were developed by literature review according to a reliability test. Data was analyzed using X2 test and t test to determine similarities between the experimental and control groups. The hypothesis was tested using repeated measures of ANOVA, t-test and Pearson correlation coefficients. The results of the study were summarized as follows: 1. The first hypothesis was accepted: a higher level of knowledge about osteoporosis was found in experimental groups who received education than to the control group during the period (F=19.82, p=.0001). 2. The second hypothesis was accepted: a higher level of life style changes about osteoporosis on experimental group were recorded than as compared to control group (t=3.55, p=.001). 3. The third hypothesis was accepted: the higher the knowledge about osteoporosis the higher the level of performance of life style changes about prevention of osteoporosis (r=.600, p=.0001). In conclusion, structured patient education in patient with fractures improved the level of knowledge about osteoporosis and more likely undergo of life style changes 6 months after the education program. Also reeducation would be needed 6 months after program ends. That is structured patient education in pamphlet form would be very effective in nursing intervention that may to result in life style changes. Therefore further research is needed to reinforce the education material and to generalize the education effect.

• Journal of Chest Surgery
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• v.27 no.5
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• pp.422-426
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• 1994

Recently, we experienced one case of multiple ribs fracture with large chest wall defects. This patient was treated with internal fixation of ribs by use of Judet`s struts and reconstruction of chest wall defects by use of Teflon mesh. Postoperative outcome was satisfactory result and its advantages were reduced duration of operation, prevention of pulmonary herniation and reduced risk of postoperative infection.

• Journal of Korean Biological Nursing Science
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• v.21 no.1
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• pp.54-61
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• 2019

Purpose: This study aimed to identify the incidence and risks for pressure ulcer among older patients with hip fracture. Methods: The subject were 215 older patients suffering from hip fracture who were admitted for surgical operation from January 1, 2012 to April 30, 2016 in a university-affiliated hospital. The incidence of pressure ulcer was collected retrospectively through medical record review and the risk factors were analyzed using Cox's proportional hazard model. Results: Out of the total, 32 patients (14.9%) developed pressure ulcer with the average occurrence period being 4.72 (${\pm}3.81$) days. Stage II pressure ulcer was the most common at 72.0%. Risk factors included ambulation status before injury (p= .039), spinal anesthesia (p= .029), and stay at intensive care unit after operation (p= .009). Conclusion: Despite pressure ulcer prevention efforts, the incidence remained relatively high. Considering the identified risk factors, more efforts is needed for early detection and prevention of pressure ulcers in such patients.