• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.427-448
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• 2014

At present, the time of easy oil and gas is over. Now, the largest part of fossil fuels is concentrated in the deepest levels of tectonic structures and in the sea shelves. One of the most cumbersome operations of their extraction is the bore-hole drilling. In connection with austere tectonic and climate conditions, their drivage every so often is associated with great and diversified technological difficulties causing emergencies on frequent occasions. As a rule, they are linked with drill string accidents. A key role in prediction of these situations should play methods of theoretical modelling. For this reason, there is a growing need for development and implementation of new numerical methods for computer simulation of critical and post-critical behavior of drill strings (DSs). In this paper, the processes of non-linear deforming of a DS in cylindrical cavity of a deep bore-hole are considered. On the basis of the theory of curvilinear flexible rods, non-linear constitutive differential equations are deduced. The effects of the longitudinal non-uniform preloading, action of torque and interaction between the DS and the bore-hole surface are taken into account. Owing to the use of curvilinear coordinates in the constraining cylindrical surface and a specially chosen concomitant reference frame, it became possible to separate the desired variables and to reduce the total order of the equation system. To solve it, the method of continuation the solution by parameter and the transfer matrix technique are applied. As a result of the completed numerical analysis, the critical states of the DS loading in the cylindrical channels of inclined bore-holes are found. It is shown that the modes of the post-critical deforming of the DS are associated with its irregular spiral curving prevailing in the zone of bottom-hole-assembly. The possibility of invariant state generation during post-critical deforming is established, condition of its bifurcation is formulated. It is shown that infinite variety of loads can correspond to one geometrical configuration of the DS. They differ each from other by contact force functions.

• Convergence Security Journal
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• v.19 no.2
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• pp.129-136
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• 2019

The main tasks of commander and staffs in ground operations are a continuation performing the process of making decisions in various situations. Since the current decision-making process is largely dependent on qualitative methods, it is difficult to integrate with the decision-making tools associated with the 4th Industrial Revolution. The purpose of this study is to suggest the process of deriving the relative importance of the evaluation factors using the AHP with focusing on assessing the avenues of approach in IPB related to the ground operation plan. The most important aspect of IPB is the evaluation of the avenues of approach. Evaluation factors include target accessibility, observation and seasons, concealment and cover-up, ease of maneuverability, and ease of transition to adjacent access roads. The existing methods are the comparison method with evaluation factors and the analysis with the advantages and disadvantages. However, it has been criticized that they regard evaluation factors as equal importance. The results show that target accessibility has the highest score related with priority when considering the criteria.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.353-359
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• 2013

Purpose: Extensive research is actively ongoing for development of an ideal bone substitute that meets the gold standard. Tooth was selected as a donor site for evaluation of potentials in bone substitutes based on its similar chemical compositions to alveolar bone. Previous studies have evaluated inorganic components of autogenous tooth bone graft material (AutoBT) and osteoconductivity. In continuation from the previous studies, the current study was conducted for analysis of organic components and evaluation of osteoinductivity of AutoBT. Methods: Forty-six extracted teeth were collected from actual patients (Korea Tooth Bank, R&D Institute). Extracted teeth were processed into AutoBT and implanted in dorsal subcutaneous muscular tissues of 15 athymic mice. Biopsy samples were harvested at two, five, and eight weeks. The Bradford assay, sodium dodecyl sulphate polyacrylamide gradient gel, and western blotting were performed for investigation of organic contents of AutoBT. Results: Histology analyses showed signs of new bone formation as early as two weeks. Results of the Bradford assay indicated the existence of noncollagenous proteins (NCP). 0.29% (2.89 mg/g) of proteins were extracted by weight in the root portion of AutoBT; 0.02% (0.029 mg/g) and 1.79% (17.93 mg/g) of proteins were measured by weight in crown and block-form of AutoBT, respectively. However, recombinant human bone morphogenetic protein-2 was not observed in AutoBT. Conclusion: Within the limitation of the current study, AutoBT induced new bone formation by NCP embedded in dentin.

• Journal of Korean Academy of Nursing
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• v.44 no.6
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• pp.726-734
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• 2014

Purpose: The purpose of this study was to evaluate the effects of the Spirituality Promotion Program(SPP) for young nurses working in the stressful university hospital environment. Methods: The study included 41 nurses in the experimental group, nurses who had worked less than 5 years and completed 8 weeks of SPP between June and July in 2011. The control group, 44 nurses, also received the same program after the study was completed. For the study, a survey was conducted of all participants concerning spirituality, perceived stress, positive and negative affect, empathy, job satisfaction, and leadership practice. Results: No significant difference was found between the two groups on study variables. Perceived stress decreased significantly in the experimental group (p=.012). Spirituality (p=.019), positive affect (p=.014), empathy (p=.004), job satisfaction (p=.016), and leadership practice (p=.021) increased significantly in the experimental group. Conclusion: The results show that the Spirituality Promotion Program has positive effects on the spiritual and psychosocial aspect of young nurses. Continuation of this program for nurses is recommended in order to help them develop their self-care ability and improve nursing competency.

• Earthquakes and Structures
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• v.14 no.1
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• pp.1-10
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• 2018

Seismic retrofitting of existing buildings and design of earth-quake resistant buildings are important issues associated with earthquake-prone zones. Use of metallic-yielding dampers as an energy dissipation system is an acceptable method for controlling damages in structures and improving their seismic performance. In this study, the optimal distribution of dampers for reducing the seismic response of steel frames with multi-degrees freedom is presented utilizing the uniform distribution of deformations. This has been done in a way that, the final configuration of dampers in the frames lead to minimum weight while satisfying the performance criteria. It is shown that such a structure has an optimum seismic performance, in which the maximum structure capacity is used. Then the genetic algorithm which is an evolutionary optimization method is used for optimal arrangement of the steel dampers in the structure. In continuation for specifying the optimal accurate response, the local search algorithm based on the gradient concept has been selected. In this research the introduced optimization methods are used for optimal retrofitting in the moment-resisting frame with inelastic behavior and initial weakness in design. Ultimately the optimal configuration of dampers over the height of building specified and by comparing the results of the uniform deformation method with those of the genetic algorithm, the validity of the uniform deformation method in terms of accuracy, Time Speed Optimization and the simplicity of the theory have been proven.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.78-83
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• 2020

Objectives: The discontinuation of bisphosphonate (BP) treatment before tooth extraction may induce medication-related osteonecrosis of the jaw (MRONJ). Whether the long-term discontinuation of BP treatment before tooth extraction affects the risk of developing MRONJ after tooth extraction or whether extended drug holidays induce systemic side effects remains unclear. The present study assessed the incidence of MRONJ among patients who underwent tooth extraction and did not discontinue BP therapy prior to the procedure. Materials and Methods: Patients were classified according to whether or not they discontinued BP therapy before tooth extraction. Differences in the incidence of MRONJ after tooth extraction were compared between the two groups using the chi-squared test. Results: The BP-continuation (BPC) and BP-discontinuation (BPDC) groups included 179 and 286 patients, respectively. One patient in the BPC group and no patients in the BPDC group developed MRONJ (P=0.385). The patients in the BPDC group stopped receiving BP therapy at a mean of 39.0±35.5 months prior to tooth extraction. Conclusion: The possibility of pre-existing MRONJ in the extraction area must be considered during the extraction procedure. Routine discontinuation of BP medications for several months before the extraction procedure should be carefully considered, as evidence of its efficacy in reducing the development of post-extraction MRONJ is limited.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2533-2539
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• 2014

Aim: To take a deeper insight into the relationship between the root of the inferior mesenteric artery (IMA) and the autonomic nerve plexuses around it by cadaveric anatomy and explore anatomical evidence of autonomic nerve preservation in high ligation of the IMA in laparoscopic surgery for colorectal cancer. Methods: Anatomical dissection was performed on 11 formalin-fixed cadavers and 12 fresh cadavers. Anatomical evidence-based autonomic nerve preservation in high ligation of the IMA was performed in 22 laparoscopic curative resections of colorectal cancer. Results: As the upward continuation of the presacral nerves, the bilateral trunks of SHP had close but different relationships with the root of the IMA. The right trunk of SHP ran relatively far away from the root of IMA. When the apical lymph nodes were dissected close to the root of the IMA along the fascia space in front of the anterior renal fascia, the right trunk of SHP could be kept in suit under the anterior renal fascia. The left descending branches to SHP constituted a natural and constant anatomical landmark of the relationship between the root of IMA and the left autonomic nerves. Proximal to this, the left autonomic nerves surrounded the root of the IMA. Distally, the left trunk of the SHP departed from the root of IMA under the anterior renal fascia. When high ligation of the IMA was performed distal to it, the left trunk of SHP could be preserved. The distance between the left descending branches to SHP and the origin of IMA varied widely from 1.3 cm to 2.3 cm. Conclusions: The divergences of the bilateral autonomic nerve preservation around the root of the IMA may contribute to provide anatomical evidence for more precise evaluation of the optimal position of high ligation of the IMA in the future.

• The Korean Journal of Pain
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• v.25 no.4
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• pp.213-220
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• 2012

Background: It has been demonstrated that the expression of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and apoptotic cell death in the dorsal root ganglion (DRG) following spinal nerve constriction injury play a role in the initiation and continuation of hyperalgesia and allodynia. The present study was designed to investigate the effects of ethyl pyruvate (EP) on mechanical and cold allodynia, TNF-${\alpha}$ expression, and apoptosis in DRG after spinal nerve ligation injury. Methods: Rats were divided into 3 groups: control, pre-EP, and post-EP. EP (50 mg/kg) was intraperitoneally injected 30 minutes before (pre-EP) or after (post-EP) surgery. Behavioral tests to determine mechanical and cold allodynia were conducted before surgery and 4 and 7 days after surgery. Seven days after surgery, TNF-${\alpha}$ protein levels in DRG were evaluated by enzyme-linked immunosorbent assay, and DRG apoptosis was determined by immunohistochemical detection of activated caspase-3. Results: Treatment with EP significantly reduced mechanical and cold allodynia following spinal nerve ligation injury. TNF-${\alpha}$ protein levels in the pre-EP ($4.7{\pm}1.2$ pg/200 ${\mu}g$; P < 0.001) and post-EP ($6.4{\pm}1.8$ pg/200 ${\mu}g$; P < 0.001) groups were 2-3 times lower than the control group ($14.4{\pm}1.2$ pg/200 ${\mu}g$). The percentages of neurons and satellite cells that co-localized with caspase-3 were also significantly lower in the pre-EP and post-EP groups than the control group. Conclusions: These results demonstrate that EP has a strong anti-allodynic effect that acts through the inhibition of TNF-${\alpha}$ expression and apoptosis in DRG after spinal nerve ligation injury.

• Perspectives in Nursing Science
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• v.17 no.2
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• pp.90-98
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• 2020

Purpose: This study examined the effects of breastfeeding education among preterm mothers. Methods: A nonequivalent control group, repeated measure, quasi-experimental study design was used. The participants comprised 46 preterm mothers recruited from the neonatal intensive care unit of a university hospital who were divided into two groups: 23 in the control group and 22 in the experimental group. The breastfeeding education program intervention to promote preterm mothers' self-efficacy used was devised based on the self-efficacy theory. The intervention program consisted of individual breastfeeding education with demonstrations and discharge education, and telephone follow-up education within one week after being discharged. The participants were surveyed before and after the intervention, and four weeks after being discharged from the newborn intensive care unit. Results: The intervention group showed a significant increase in breastfeeding self-efficacy compared with the control group (F=6.92, p=.003) and showed a significant increase in their breastfeeding attitude score (F=3.49, p=.039). Four weeks after discharge, the breastmilk volume of the intervention group increased significantly (t=-2.87, p=.006), and the same group continued to breastfeed more compared with the control group (χ²=4.50, p=.049). Conclusion: This study suggests that the preterm breastfeeding program had a positive effect on breastfeeding self-efficacy, breastfeeding attitude, and extending the breastfeeding period among preterm mothers.

• Journal of Chest Surgery
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• v.51 no.4
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• pp.231-240
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• 2018

Background: Analyses of the efficacy and safety of transcatheter aortic valve replacement (TAVR) in most countries have been based on outcomes obtained in accordance with national practice guidelines and monitoring protocols. The purpose of this study is to share our experience regarding the process for establishing guidelines and monitoring protocols for the use of TAVR in Korea, in the hopes that it may be helpful to others undergoing a similar process in their own country. Methods: The Korean guidelines for TAVR were established on June 1, 2015 in through a tri-party agreement involving the Department of Health and Welfare, the Korean Society of Thoracic and Cardiovascular Surgery and the Korean Society of Cardiology. We agreed to monitor the guidelines transparently and to exchange opinions regarding amendments or continuation of its contents after 3 years of monitoring. Results: The monitoring meetings were not held as regularly as agreed, and monitoring was also made difficult by insufficient and incomplete data. Nevertheless, during the meetings, measures to improve the monitoring process were discussed, and accordingly, an agreement was made to continue the monitoring process, with the aim of completing data collection by 2018. Conclusion: Compliance with guidelines is critical for assessing the efficacy and safety of TAVR. Moreover, the TAVR monitoring process must be properly conducted for an accurate evaluation to be made. Any country planning to introduce TAVR may encounter difficulties with regards to the optimal initiation strategy and subsequent monitoring. Nevertheless, continued efforts should be made to persuade the government and the corresponding medical societies to facilitate the optimal application of TAVR.