• The korean journal of orthodontics
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• v.44 no.5
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• pp.246-253
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• 2014

Objective: To evaluate the bioactivity, and the biomechanical and bone-regenerative properties of Ti6Al4V miniscrews subjected to anodization, cyclic precalcification, and heat treatment (APH treatment) and their potential clinical use. Methods: The surfaces of Ti6Al4V alloys were modified by APH treatment. Bioactivity was assessed after immersion in simulated body fluid for 3 days. The hydrophilicity and the roughness of APH-treated surfaces were compared with those of untreated (UT) and anodized and heat-treated (AH) samples. For in vivo tests, 32 miniscrews (16 UT and 16 APH) were inserted into 16 Wistar rats, one UT and one APH-treated miniscrew in either tibia. The miniscrews were extracted after 3 and 6 weeks and their osseointegration (n = 8 for each time point and group) was investigated by surface and histological analyses and removal torque measurements. Results: APH treatment formed a dense surface array of nanotubular TiO2 layer covered with a compact apatite-like film. APH-treated samples showed better bioactivity and biocompatibility compared with UT and AH samples. In vivo, APH-treated miniscrews showed higher removal torque and bone-to-implant contact than did UT miniscrews, after both 3 and 6 weeks (p < 0.05). Also, early deposition of densely mineralized bone around APH-treated miniscrews was observed, implying good bonding to the treated surface. Conclusions: APH treatment enhanced the bioactivity, and the biomechanical and bone regenerative properties of the Ti6Al4V alloy miniscrews. The enhanced initial stability afforded should be valuable in orthodontic applications.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.133-137
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• 2011

In this study, illite was size-reduced using a wet-ball-milling treatment to improve its dispersion. Changes in illite particle size, size distribution, and dispersion characteristics after varying the treatment period were investigated. And the dispersion and dispersion stability of illite solution after 2 h wet ball milling treatment with different pH conditions were also evaluated. The illite particle size significantly decreased as the treatment time increased and the size reduction effect of wet ball milling deteriorated above 2 h treatment time. In addition, illite particle size was more evenly distributed as the treatment time increased. X-ray diffraction (XRD) analysis showed that no crystal structural changes of illite were induced, but the characteristic peak of illite the weaker due to the size reduction and exfoliation, as the treatment time increased. Zeta potential analysis showed that the illite dispersion improved, as the treatment time increased. The illite wet-ball-mill treated at pH 2 had the lowest dispersion stability. Illite dispersion and dispersion stability increased as pH increased, due to the increase in surface ionization. Hence, the results showed that as the treatment time increased, the illite particle size decreased, and dispersion and dispersion stability improved due to the increase in surface energy and repulsion force between particles.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.8
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• pp.1047-1054
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• 2018

This paper proposed the strategies for controlling both the heater temperature and the output voltage of a single-phase inverter for the heat treatment. The single-phase inverter system for the heat treatment controls the heater temperature to its reference one, and also it limits the inverter output voltage to 60 V for safety. The stability may be deteriorated due to the large time constant difference between the heater temperature and inverter output voltage. In order to ensure the stability, a hysteresis on/off control approach for the heater temperature control is adapted, and both the open-loop and the closed-loop control strategies of the output voltage are suggested. The performances for the proposed strategies are demonstrated with the experiments.

• Elastomers and Composites
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• v.54 no.3
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• pp.241-246
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• 2019

Carbon master batch (CMB) rubber sheets, which are stored in stacks, are difficult to separate during reuse because of the adhesion between sheets caused by the stacked weight over time. To solve this problem, in the actual rubber product manufacturing process, various anti-tacking agents (solid powder or liquid surfactants) are applied to the sheet surface. In this study, the emulsion samples of zinc (Zn)-stearate/triethanolamine (TEA)-stearate mixtures were prepared using TEA-stearate as a surfactant, prepared using an industrially manufactured Zn-stearate powder, and their basic anti-tacking properties were studied. During the process of manufacturing emulsion, a heat treatment process and an auxiliary surfactant were introduced to improve the dispersion stability. Results showed that the heat-treated sample exhibited a significant improvement in terms of sedimentation, storage stability, and anti-tacking characteristics since the Zn-stearate particles were reduced to a smaller size by the heat-treatment than that of the original Zn-stearate powder.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.59-62
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• 2002

Recently, advanced system for water and wastewater treatment is introduced and operated because of water pollution and etc. One of this System makes use of O3(Ozone) for water and wastewater treatment. In airtight concrete structure, waterproofing phase as well as water are affected by strong oxidative O3 in the long-term. For this reason, material stability against O3 is examined. Consequently, the purpose of this study is to find out material stability an object of epoxy resin by way of accelerated O3 testing.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.215-222
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• 2008

Multilocation trials on 36 rice(Oryza sativa) genotypes of 3 different maturity groups were conducted at four different locations of Orissa for 3 years and 30 ragi(Eleusine coracana) genotypes of 2 different maturity groups were evaluated in three environmental conditions for 3 years. Grain yield data were subjected to stability analysis following linear regression model to estimate adaptability and stability parameters, i.e. b, and $S^2d$ Stability of performance of genotypes was also estimated by two other stability parameters viz., ecovalence W and AMMI stability value ASV. The rice and ragi genotypes of different duration groups showed wide variation in their mean yield, b, $S^2d$, W and ASV parameters. Seeds of the 36 rice and 30 ragi genotypes were treated with 500 and 100 ppm aqueous solution of maleic hydrazide(MH) for 24 hours, respectively to study MH-sensitivity. Sensitivity of genotypes to MH treatment was estimated in terms of seedling growth inhibition index(SGI). The rice and ragi genotypes showed wide differences in their MH-sensitivity in terms of SGI. Relationship of MH-sensitivity of genotypes with their yielding ability, adaptability and stability of performance was tested by contingency $x^2$ test. Low sensitivity of rice and ragi genotypes to MH in terms of SGI appeared to be good indicators of high yielding ability of genotypes. Also, low and high MH-sensitivity of genotypes would be a good indicator of better adaptability to rich and poor environments, respectively, in ragi but not in rice. Low MH-sensitivity of genotypes could be the good indicator of stability of yield performance in rice but not in ragi.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.407-412
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• 2011

Purpose: The purpose of the present study was to evaluate the postoperative skeletal stability of two-jaw surgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) via surgery first orthodontic treatment (SFOT) in class III malocclusion. Methods: Thirty-two patients who had two-jaw surgery via SFOT were included in this study. Serial lateral cephalograms were obtained before (T0), immediately after (T1), and six months after (T2) surgery. Twelve variables were measured for horizontal and vertical skeletal stability as well as for dental change. All measurements were evaluated statistically by a paired t-test ($P$ <0.05). Results: The mean skeletal changes were $0.1{\pm}2.5$ mm at point A and $-12.0{\pm}7.4$ mm at the pogonion. The mean horizontal relapse was 11.6% at the pogonion, and the mean vertical surgical changes included an upward displacement of $2.1{\pm}7.1$ mm and a forward displacement of $1.4{\pm}4.6$ mm at the pogonion. Upper incisor inclination decreased after surgery and was maintained at T2, and lower incisors were proclined from T1 to T2 by postsurgical orthodontic treatment. Conclusion: Postoperative skeletal stability of two-jaw surgery via surgery first orthodontic treatment in class III malocclusion was clinically acceptable.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.2
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• pp.115-123
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• 2021

PURPOSE: This study aimed to investigate the benefits of thoracic manipulation and the trunk stability exercises on spine trunk flexibility and the pain index of chronic low back pain patients. METHODS: The study included 44 patients suffering from chronic low back pain. The participants were divided into two groups: the first group was assigned for trunk stability exercises (TSE), and the second group was randomly assigned TSE and thoracic manipulation at the same time (TSE+TM). Both groups carried out each assigned treatment thrice a week for 8 weeks. The study outcome was based on assessment of spine trunk flexibility and the pain index. Spine trunk flexibility was measured by spine flexion and extension through a range of motion and thoracic cage circumference. The pain index was measured using a visual analog scale (VAS). RESULTS: Spine flexion and extension range of motion showed a significant difference within each group and between the groups before and after the treatment. The measurement of the thoracic cage circumference also showed a notable difference within each group and between the groups before and after the treatment. There was no change in the pain index. CONCLUSION: These results indicate that thoracic manipulation with the trunk stability exercises is an efficient treatment for improving the spine trunk flexibility and soothing pain for chronic low back pain patients.

• Physical Therapy Korea
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• v.15 no.1
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• pp.30-37
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• 2008

This study was designed to examine the effects of temporary immobilization of the ankle and knee joints on standing in healthy young adults with the use of a postural control mechanism. The subjects were twenty-four college students (12 males and 12 females, aged between 20 and 28). A Biodex balance system SD 950-302 and its software were used to measure indirect balance parameters in standing. Each subject underwent postural stability tests in 4-different joint conditions: free joints, ankle immobilization only, knee immobilization only, and ankle and knee immobilization. In addition, the postural stability test was conducted once with the subject's eyes open and once with the eyes closed conditions. For data analysis of the postural stability tests, the overall stability index, antero-posterior stability index, and medio-lateral stability index were recorded. The overall stability index (p=.000) and medial-lateral index (p=.003) were significantly greater different conditions with eyes closed in postural stability. Therefore, the eyes closed condition is expected to be used as an effective postural stability training for treatment planning in patients with unstable postures. In addition, training based on the dynamic multi-segment model can improve postural stability and is available to therapeutic programs, helping people with unstable balance to reduce their risk of falling.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.2
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• pp.107-112
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• 2001

The prosthodontic treatment of severely resorbed edentulous patients has been one of the frustrating areas due to extensive loss of tissues. The integrated neuromuscular balance among tongue, lip, and cheek is compromised. The retention, stability, and support are the three major factors to influence the clinical outcome. Fish described a denture as having three surface, with each surface playing an independent and important role in the over all fit, stability, and comfort of the denture. He recommended that the polished surface should be a series of inclines so that pressure from muscular activity will retain dentures. Within the denture space there is an area that has been termed the neutral zone. The neutral zone is that area in the mouth where, during function, the forces of the tongue pressing outward are neutralized by the forces of the cheeks and lips pressing inward. According to Jacobson and Krol, neuromuscular control interacts to provide retention and the relationship of polished surface of denture base to the surrounding muscular structure of orofacial capsule facilitates the stability and retention. This neutral zone concept has been demonstrated with various modification by a number of authors. The theory used to develop the denture base contours is based on the belief that the muscle should functionally mold not only the border but the entire polished surface. Lott and Walsh reported the clinical success on complete mandibular dentures with application of neutral zone concept. A number of studies demonstrated that denture stability and retention are more dependent on correct position of the teeth and correct contour of external surfaces of the denture in a severely resorbed alveolar ridge. This article presents a prosthodontic approach to treatment of a edentulous patient using neutral zone technique to improve the retention and stability of the prosthesis.