• Journal of Korean Dental Science
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• 제10권2호
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• pp.66-73
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• 2017

Purpose: To evaluate the effect of different-sized drill tips and laser irradiation times on the initial stability of orthodontic miniscrews placed in Er,Cr:YSGG-laser pre-drilled holes in an animal model. Materials and Methods: Laser pre-drilled holes were made in dog mandibular bone with an Er,Cr:YSGG laser using irradiation times of 5, 7, 9, 11, and 13 seconds, and tip diameters of 0.4 and 0.6 mm. The maximum diameter and depth of the pre-drilled holes was measured with micro computed tomography. The maximum insertion torque was measured during placement the miniscrew. Result: Laser pre-drilled holes were conical shaped. The maximum diameter of pre-drilled holes increased with longer laser irradiation times (P>0.05) and larger tip diameters (P<0.05). The depth of pre-drilled holes increased with longer laser irradiation times and larger tip diameters (P<0.05). When the 0.4 mm tip, but not the 0.6 mm tip, was used, the insertion torque decreased significantly with longer laser irradiation times (P<0.05). Conclusion: Tip diameter impacted insertion torque more than irradiation time. It takes at least 9 seconds using a 0.6 mm tip to create a 0.8 mm diameter and 1.0 mm depth hole in thick cortical bone.

• 한국압력기기공학회 논문집
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• 제14권1호
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• pp.1-7
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• 2018

Materials in nuclear power plants can be embrittled by neutron irradiation. According to existing studies, the effect of the material property by irradiation embrittlement can be approximately simulated by cold working (pre-strain). In this study, finite element damage analysis method using the stress-modified fracture strain model is proposed to predict J-Resistance curves of irradiated SUS316 stainless steel. Experimental data of pre-strained SUS316 stainless steel material are obtained from literature and the damage model is determined by simulating the tensile and fracture toughness tests. In order to consider damage caused by the pre-strain, a pre-strain constant is newly introduced. Experimental J-Resistance curves for various degrees of pre-strain are well predicted.

• 한국염색가공학회지
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• 제17권6호
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• 펄프종이기술
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• 제47권6호
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• pp.81-88
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• 2015

The molecular weight (MW) and crystallinity of cotton linter need to be controlled to be dissolved well in N-methylmorpholine N-oxide (NMMO) solvent for manufacturing regenerated fibers of clothing fabrics. Electron beam irradiation or sulfuric acid pre-treatment followed by alkaline peroxide bleaching has been used to control MW effectively and to improve brightness of cotton linter. Auto-hydrolysis of cotton linter without electron beam irradiation or chemical pre-treatment was found to be effective as an alternative pre-treatment method. Removal of metal ions, that hampered dissolution of cotton linter by NMMO, was also investigated when the auto-hydrolysis was accompanied with ionic polymers and chelating agent.

• 한국동물학회지
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• 제8권2호
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• pp.33-36
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• 1965

We have carried out a study on the modification of the frequency of X-ray induced lethal and slow growing mutations by colchincine treatment before and after X-ray irradiation in Paramecium aurelia. 1. Lethal and slow-growing mutation induced by X-ray in Paramecium aurelia were reduced by colchicine treatment. 2. The effects of colchicine on the X-ray induced mutations were remarkable in the radiosensitive stages of cell division. 3. The pre-irradiation treatment with colchicine showed no significant influence on the frequency of mutations. 4. It is believed that the reduction of mutation induced by X-ray after treatment with colchicine was due to the fact that the delay of the cell division allowed more time for the pre-mutational damage to recover.

• Radiation Oncology Journal
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• 제32권4호
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• pp.221-230
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• 2014

Purpose: To evaluate the risk of vertebral compression fracture (VCF) after conventional radiotherapy (RT) for colorectal cancer (CRC) with spine metastasis and to identify risk factors for VCF in metastatic and non-metastatic irradiated spines. Materials and Methods: We retrospectively reviewed 68 spinal segments in 16 patients who received conventional RT between 2009 and 2012. Fracture was defined as a newly developed VCF or progression of an existing fracture. The target volume included all metastatic spinal segments and one additional non-metastatic vertebra adjacent to the tumor-involved spines. Results: The median follow-up was 7.8 months. Among all 68 spinal segments, there were six fracture events (8.8%) including three new VCFs and three fracture progressions. Observed VCF rates in vertebral segments with prior irradiation or pre-existing compression fracture were 30.0% and 75.0% respectively, compared with 5.2% and 4.7% for segments without prior irradiation or pre-existing compression fracture, respectively (both p < 0.05). The 1-year fracture-free probability was 87.8% (95% CI, 78.2-97.4). On multivariate analysis, prior irradiation (HR, 7.30; 95% CI, 1.31-40.86) and pre-existing compression fracture (HR, 18.45; 95% CI, 3.42-99.52) were independent risk factors for VCF. Conclusion: The incidence of VCF following conventional RT to the spine is not particularly high, regardless of metastatic tumor involvement. Spines that received irradiation and/or have pre-existing compression fracture before RT have an increased risk of VCF and require close observation.

• Transactions on Electrical and Electronic Materials
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• 제10권1호
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• pp.16-19
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• 2009

We have studied the liquid crystal alignment properties for various alignment methods on the homogeneous polyimide surface. Suitable liquid crystal alignment for one-side alignment cell on the polyimide surface by all alignment method was observed. Highly pre-tilt angle of the NLC for both-side rubbing cell was measured. But, low pre-tilt angle of the NLC for one-side ion beam and UV irradiation cell was observed. We consider that the pre-tilt angle of NLC for one-side ion beam and UV irradiation on the PI surface is lower than that of the PI surface with rubbing. Also, the suitable transmittance-voltage curves for the one-side rubbing TN-LCD on the PI surface with one-side UV irradiation were measured. Also, good response time characteristics of the one-side rubbing TN-LCD on the polyimide surface with one-side UV irradiation can be measured.

• 한국작물학회지
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• 제10권
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• pp.45-50
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• 1971

방사선조사시 열처리의 효과를 알기 위하여 수도종자에 방사선조사시 열전후처리를 행하였던바$M_1$ 세대의 생물학적인 반응 및 $M_2$ 세대의 변이율에 대해 몇가지 결과를 얻었다. 1. 방사선선량 20kR에서 열전처리는 방사선단독조사에 비해 생물학적인 장해를 적게하고 변이율을 증가시켰다. 2. 방사선단독조사 및 조사전열처리에 비해 heat shocking으로서 열후처리하는 것은 변이율을 증가시켰다. 3. 열전처리에 의해 $M_1$ 세대의 장해가 적고 변이율이증가되는 가장 효과적인 열처리온도 및 시간은 6$0^{\circ}C$에서 30분간이었다. 4. 열처리는 방사선단독조사에 비해 mutation spectrum을 달리했다.

• IMMUNE NETWORK
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• 제11권1호
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• pp.68-78
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• 2011

Background: Graft-versus-host disease (GVHD) is a huddle for success of hematopoietic stem cell transplantation. In this study, effects of irradiation dose on immune kinetics of GVHD were investigated using B6 ${\rightarrow}$ BALB.B system, a mouse model for GVHD after MHC-matched allogeneic transplantation. Methods: BALB.B mice were transplanted with bone marrow and spleen cells from C57BL/6 mice after irradiation with different doses. Leukocytes residing in the peripheral blood and target organs were collected periodically from the GVHD hosts for analysis of chimerism formation and immune kinetics along the GVHD development via flow cytometry. Myeloid cells were tested for production of IL-17 via flow cytometry. Results: Pre-conditioning of BALB.B hosts with 900 cGy and 400 cGy resulted in different chimerism of leukocytes from the blood and affected survival of GVHD hosts. Profiles of leukocytes infiltrating GVHD target organs, rather than profiles of peripheral blood leukocytes (PBLs), were significantly influenced by irradiation dose. Proportions of IL-17 producing cells in the infiltrating $Gr-1^+$ or $Mac-1^+$ cells were higher in the GVHD hosts with high does irradiation than those with low dose irradiation. Conclusion: Pre-conditioning dose affected tissue infiltration of leukocytes and cytokine production by myeloid cells in the target organs.

• 대한한방내과학회지
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• 제25권4호
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• pp.25-33
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• 2004

Objective : The effects of Indium-Gallium-Aluminium-Phosphide(InGaAlP) laser transcutaneous irradiation on heart rate variability(HRV) in healthy adults are investigated with power spectrum analysis(PSA) of HRV. Methods : The control group consisted of 20 healthy volunteers (10 men, 10 women). The experiment was divided into 5 different periods, the pre-1st laser period(10 minutes), the 1st laser period(30 minutes), the post-1st laser period(5 minutes), the 2nd laser period( 30 minutes) and the post-2nd laser period(30 minutes). HRV was measured for 5 minutes at the pre-1 st laser period, the post-l st laser period and the post-2nd laser period. The laser period is the period in which InGaAlP laser transcutaneous Irradiation treatment occurs. Results : 1. SDNN of volunteers at post-1st laser period and post-2nd laser period significantly increased compared with that of the pre- 1 st laser period. 2, Ln(VLF) at post-I st laser period significantly increased compared with that of pre-1st laser period, while Ln(HF) at post-2nd laser period significantly decreased compared with those of pre- I st laser period and post-1st laser period, 3. Ln(TP) at post-1st laser period and post-2nd laser period significantly increased compared with that of pre-1st laser period, 4, LF/HF Ratio at post-2nd laser period significantly increased compared with those of pre-1st laser period and post-1st laser period. But the other variables did not significantly change. Conclusions : The results suggest that InGaAlp laser transcutaneous Irradiation in healthy adults is associated with the autonomic nervous systems. Further study is needed for investigating the effects of laser irradiation on autonomic nervous systems.