• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.27 no.2
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• pp.108-113
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• 2016

Background and Objectives : After thyroidectomy, many patients experience problems report such things as reduced voice range and vocal fatigue, swallowing problems without superior and recurrent laryngeal nerve injury. The purpose of this study was to evaluate voice and swallowing problems before and after thyroid surgery without laryngeal nerve injury. Materials and Methods : Ninety-three patients who underwent thyroidectomy without laryngeal nerve injury and completed the follow-up evaluations were studied between June 2013 and December 2015. Each evaluation was performed preoperatively, as well as 1 week, 1 month postoperatively. Analysis was performed including voice handicap index (VHI), dysphagia handicap index (DHI), and acoustic voice analysis. Results : Patients show significant variation of parameters in the fundamental frequency (F), maximal phonation time (MPT), shimmer, jitter and soft phonation index (SPI) early after operation, and most of them showed recovery of parameters after 1month of operation. Perceptive complaint of voice and swallowing also showed significant decreased after operation (p<0.005). After 1month of operation, MPT, highest frequency and frequency ranges still showed significant decreased parameters. Comparing acoustic and perceptive parameters of total thyroidectomy and lobectomy, there was no significant changes between them except highest frequency (p=0.042). Conclusion : The results from both subjective and objective evaluations show voice and swallowing disturbance after thyroidectomy even in the absence of laryngeal nerve and provide patients information about the recovery process after surgery. Highest frequency parameter showed most significant changes after operation.

• Journal of the Korean GEO-environmental Society
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• v.21 no.9
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• pp.25-32
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• 2020

The underground utilities installed under the ground is an important civil engineering structure, such as water supply and sewerage pipes, underground power lines, various communication lines, and city gas pipes. Such underground utilities can be exposed to risk due to external factors such as concentrated rainfall and vehicle load, and it is important to select and construct an appropriate backfill material. Currently, a method mainly used is to fill the soil around the underground utilities and compact it. But it is difficult to compact the lower part of the buried pipe and the compaction efficiency decreases, reducing the stability of the underground utilities and causing various damages. In addition, there are disadvantages such as a decrease in ground strength due to disturbance of the ground, a complicated construction process, and construction costs increase because the construction period becomes longer, and civil complaints due to traffic restrictions. One way to solve this problem is to use a liquid filler. The liquid filler has advantages such as self-leveling ability, self-compaction, fluidity, artificial strength control, and low strength that can be re-excavated for maintenance. In this study, uniaxial compression strength test and fluidity test were performed to characterize the mixed soil using marine clay, stabilizer, and in-situ soil as backfill material. A freezing-thawing test was performed to understand the strength characteristics of the liquid filler by freezing, and in order to examine the effect of the filling materials on the corrosion of the underground pipe, an electrical resistivity test and a pH test were performed.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.781-790
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• 2014

Contaminants such as organic matters, nutrients and toxic chemicals in rivers and lakes with a weak flow rate are first removed from the water and accumulated in the sediments. Subsequently, they are released into the water column again, posing direct/indirect adverse effects on the water quality and aquatic ecosystems. In particular, phosphorus is known to accelerate the eutrophication phenomenon when it is released into the water column via physical disturbance and biological/chemical actions as one of important materials that determine the primary production of aquatic ecosystems and an element that is stored mainly in the sediments in the process of material circulation in the body of water. In this study, the effect on reducing phosphorus release in sediments was analyzed by applying different capping materials to lake water, where the effect of aquatic microorganisms is taken into account, and to distilled water, where the effect of microorganisms is excluded. The experimental results showed that capping with chemical materials such as Fe-gypsum and $SiO_2$-gypsum further reduced the phosphorus release by at least 40% compared to the control case. Composite materials like granule gypsum+Sand showed over 50% phosphorus release reduction effect. Therefore, it is determined that capping with chemical materials such as granule-gypsum and eco-friendly materials such as sand is effective in reducing phosphorus release. The changes in phosphorus properties in the sediments before and after capping treatment showed that gypsum input helped to change the phosphorus that is present in lake sediments into apatite-P, a stable form that makes phosphorus release difficult. Based on the above results, it is expected that the application of capping technology will contribute to improving the efficiency of reducing phosphorus release that occurs in river and lake sediments.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.132-142
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• 2010

Hypokalemia usually reflects total body potassium deficiency, but less commonly results from transcellular potassium redistribution with normal body potassium stores. The differential diagnosis of hypokalemia includes pseudohypokalemia, cellular potassium redistribution, inadequate potassium intake, excessive cutaneous or gastrointestinal potassium loss, and renal potassium wasting. To discriminate excessive renal from extrarenal potassium losses as a cause for hypokalemia, urine potassium concentration or TTKG should be measured. Decreased values are indicative of extrarenal losses or inadequate intake. In contrast, excessive renal potassium losses are expected with increased values. Renal potassium wasting with normal or low blood pressure suggests hypokalemia associated with acidosis, vomiting, tubular disorders or increased renal potassium secretion. In hypokalemia associated with hypertension, plasam renin and aldosterone should be measured to differentiated among hyperreninemic hyperaldosteronism, primary hyperaldosteronism, and mineralocorticoid excess other than aldosterone or target organ activation. Hypokalemia may manifest as weakness, seizure, myalgia, rhabdomyolysis, constipation, ileus, arrhythmia, paresthesias, etc. Therapy for hypokalemia consists of treatment of underlying disease and potassium supplementation. The evaluation of hyperkalemia is also a multistep process. The differential diagnosis of hyperkalemia includes pseudohypokalemia, redistribution, and true hyperkalemia. True hyperkalemia associated with decreased glomerular filtration rate is associated with renal failure or increased body potassium contents. When glomerular filtration rate is above 15 mL/min/$1.73m^2$, plasma renin and aldosterone must be measured to differentiate hyporeninemic hypoaldosteronism, primary aldosteronism, disturbance of aldosterone action or target organ dysfunction. Hyperkalemia can cause arrhythmia, paresthesias, fatigue, etc. Therapy for hyperkalemia consists of administration of calcium gluconate, insulin, beta2 agonist, bicarbonate, furosemide, resin and dialysis. Potassium intake must be restricted and associated drugs should be withdrawn.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.121-132
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• 2007

This paper examines the spatial and temporal variability in the water depth caused by artificial structures in Geum Estuary of South Korea. Water depth data set extracted from marine maps of 1979, 1990, 1996 and 2004 were used in a GIS to derive volumetric estimates of gains and losses of sedimentary material. Artificial structures caused above 2m in water depth to be shallow between 1979 and 2002 in the estuary system, particularly through disturbance of a natural transport in suspended sediment concentrations. The mutt significant change in suspended sediment transport were observed in area affected by embankment for fresh water, inducing the water depth shallower than before in almost 80% of the area. This was probably because of an continuous abundant mud supply from coastal river oven after blocking the fresh water. The spatial analysis made it possible to identify area wide patterns of water depth change subject to many different type of artificial structures, which tanner be acquired by traditional field sampling. It is anticipated thai this research could be used as a valuable reference to confirm the outputs from past field researches for sedimental process in more visual and quantitative manner.

• Journal of Korean Society on Water Environment
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• v.33 no.5
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• pp.511-524
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• 2017

This study was carried out for the purpose of creating a restoration plan to improve the ecological quality of the Changwon and Nam streams. Based upon the results of comprehensive diagnostic assessment, restoration priority was given to the upstream reach, where conservation status is relatively superior. Restoration level was usually determined to practice active restoration as conservation, and the states of both Changwon and Nam streams were not so good. Restoration plans, by reach, were classified into "upstream", "midstream", and "downstream" were suggested in both terms of horizontal section frame and vegetation-based on the result of diagnostic assessment and the reference information. "Upstream", "mid-stream" and the "downstream" of Changwon and Nam streams were classified into "small-gravel- mountainous", "small-sand-plain", and "small-clay-plain streams" respectively (based on scale, and substrate and slope of river bed). The spatial arrangement of vegetation was laid out in diagram form by reflecting micro-topography and the water level of the horizontal section of river. Information regarding species composition was recommended as dominant species, which appear frequently in three vegetation zones composed of herbaceous plants, shrubs and trees and sub-tree- dominated zones divided by reflecting disturbance regime, depending on position on the horizontal section of river. Moreover, there have been prepared not only plans to improve the terrestrial ecosystems around the streams but also plans to create ecological networks, which can serve to improve the ecologic quality of the whole regional environment by serving to connect streams and terrestrial ecosystems, a process probably necessary and definitely recommended to realize true (genuine) restoration. Plans for ecological parks and networks were prepared by mimicking the species composition of Alnus japanica community, Zelkova serrata community, Carpinus laxiflora community, Quercus aliena community, and Q. serrata community.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.185-198
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• 2009

Tooth anklylosis is defined as the adhesion state of alveolar bone to dentin or cementum. Trauma, disturbed metabolic disease, and congenital disease have been given as etiologic factors. Complications of tooth ankylosis are tipping of the neighboring teeth, space loss, and supraeruption of the opposing teeth. Particularly if dental ankylosis occurs in maxillary incisors of a growing child, the ankylosed tooth can not move vertically with subsequent disturbance in vertical growth of the alveolar process. With an appropriate treatment approach, an esthetic condition must be achieved especially in the maxillary anterior region. In this report, two cases are presented which were treated by the surgical repositioning method. One is treated by alveolar bone distraction osteogenesis which used a tooth-borne type distraction device and the other by single tooth osteotomy.

• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.1-10
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• 2003

The successional status and potential natural vegetation were examined in the natural deciduous forest in Mt. Chombong area. The examination was based on the subsequent process of generation replacement by understory saplings for the dominant canopy trees within 106 20mx20m square sample plots. The transition matrix model, which was modified from mathematical theory of Markov chain, was employed to analyze the successional status of the study forest. The model suggests that study forest is still seral, and it is considered to be more than 500 years away from the steady state or climax in terms of species composition. The simulations predict a remarkable decrease in the proportion of species composition of the present dominant Quercus mongolica and Kalopanax pictus from current 42.6% and 8.1% to less than 13.3% and 0.5%, respectively, at the steady state. On the contrary, the proportions of Abies holophylla, Acer mono, Fraxinus mandshurica, Tilia amurensis, and Acer pseudo-sieboldianum will increase at the steady state. The change of predicted composition ratio was generally coincide with the result of tolerance index to be compared with the study model. The hypothesis and sensitivity of the model were also discussed to evaluate the applicability to the real situation. The overall results indicated that the present dynamics of the forest must reflect the seral state due to previous disturbance mainly by human related interference.

• Journal of the Korean earth science society
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• v.27 no.3
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• pp.279-288
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• 2006

We incorporated cooperative learning focusing on the 'Crustal Deformation' in five classes of second grade students, at an all-girls' middle school of Gimje city. The groups of cooperative learning were composed of four members of students each, according to the heterogeneous level. We conducted a pretest on the students' preference before incorporating the cooperative learning. After ten weeks of cooperative school work, the students took a post test with the same questions as the pretest. The result of this method greatly impacted the change on the students' scientific preference. It means that the students showed a positive change in their awareness of and participation in science classes, compared to before. However it is difficult to distinguish the differences in their scientific attitude on the recognition about scientists and habits which make them think scientifically. This resulted from the short period of ten weeks which is not sufficient to carry out the study strategy effectively. Surveys of the students on cooperative learning indicates that the middle level students prefer this method unlike the higher or lower level students. we are convinced that they can learn from the students of higher level and are able to help the lower level with the interaction through cooperative learning. According to the result of the survey, the method has some weaknesses; it arouses the high noise levels and consequent disturbance due to verbal interaction and of conflicts due to disagreements when they discuss the process. On the contrary, advantages are developing the students's interest in science class, helping them to learn, creating positive participation in class, and fostering mutual collaboration with other students through cooperative learning.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.4
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• pp.235-243
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• 2019

Osseointegration has been reported to be a dynamic process in which the alveolar bone comes in direct contact with the implant. Various methods were tried to evaluate degree of osseointegration and the measurement of bone-implant contact (BIC) have been commonly used among them. To properly assess the BIC, only histologic analysis is available. However, few studies evaluated BIC of successfully osseointegrated implants in humans. Thus, this is a unique opportunity when implants should be explanted due to inappropriate positioning of implant, presence of pain or sensory disturbance, or broken screw or fixture. This report presents a case of the implant underwent 3-year functional load and a histologic analysis after the fixture fracture. The histomorphometric analysis revealed 53.1% of BIC measured along the whole implant and 70.9% measured only in subcrestal area, respectively. In the present study, although the implant was fractured, a high degree of BIC was observed.