• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.111-117
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• 2016

Vagal nerve activity has been known to play a crucial role in the induction and maintenance of atrial fibrillation (AF). However, it is unclear how the distribution and concentration of local acetylcholine (ACh) promotes AF. In this study, we investigated the effect of the spatial distribution and concentration of ACh on fibrillation patterns in an in silico human atrial model. A human atrial action potential model with an ACh-dependent $K^+$ current ($I_{KAch}$) was used to examine the effect of vagal activation. A simulation of cardiac wave dynamics was performed in a realistic 3D model of the atrium. A model of the ganglionated plexus (GP) and nerve was developed based on the "octopus hypothesis". The pattern of cardiac wave dynamics was examined by applying vagal activation to the GP areas or randomly. AF inducibility in the octopus hypothesis-based GP and nerve model was tested. The effect of the ACh concentration level was also examined. In the single cell simulation, an increase in the ACh concentration shortened $APD_{90}$ and increased the maximal slope of the restitution curve. In the 3D simulation, a random distribution of vagal activation promoted wavebreaks while ACh secretion limited to the GP areas did not induce a noticeable change in wave dynamics. The octopus hypothesis-based model of the GP and nerve exhibited AF inducibility at higher ACh concentrations. In conclusion, a 3D in silico model of the GP and parasympathetic nerve based on the octopus model exhibited higher AF inducibility with higher ACh concentrations.

• Journal of Biomedical Engineering Research
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• v.41 no.5
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• pp.185-194
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• 2020

Arrhythmia is basically diagnosed with the electrocardiogram (ECG) signal, however, ECG is difficult to measure and it requires expert help in analyzing the signal. On the other hand, the radial pulse can be measured with easy and uncomplicated way in daily life, and could be suitable bio-signal for the recent untact paradigm and extensible signal for diagnosis of Korean medicine based on pulse pattern. In this study, we developed an irregular radial pulse detection algorithm based on a learning model and considered its applicability as arrhythmia screening. A total of 1432 pulse waves including irregular pulse data were used in the experiment. Three data sets were prepared with minimal preprocessing to avoid the heuristic feature extraction. As classification algorithms, elastic net logistic regression, random forest, and extreme gradient boosting were applied to each data set and the irregular pulse detection performances were estimated using area under the receiver operating characteristic curve based on a 10-fold cross-validation. The extreme gradient boosting method showed the superior performance than others and found that the classification accuracy reached 99.7%. The results confirmed that the proposed algorithm could be used for arrhythmia screening. To make a fusion technology integrating western and Korean medicine, arrhythmia subtype classification from the perspective of Korean medicine will be needed for future research.

• Journal of Life Science
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• v.14 no.1
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• pp.32-37
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• 2004

A portion of ribosomal internal transcribed spacer (ITS) 2 was sequenced from the samples of Pseudo nitzschia (P. deticatissima, P. multiseries, P. pungens and P. subfraudulenta) to investigate the genetic characteristics by measuring tile magnitude of genetic diversity and the degree of similarity coefficient using random amplified polymorphic DNAs (RAPD)-PCR patterns. The phylogenetic trees inferred from the genetic distance analyses showed the placement of P. delicatissima formed a quite long distance from p. P. multiseries, P. pungens, and even P. subfraudulenta. The phylogenetic tree from RAPD patterns showed that P. multiseries and P. pungens had dissimilarity coefficient of 0.31, while P. delicatissima and three species of Pseudo-nitzschia had that of 0.81. It is likely thought that the genetic position of P. delicatissima formed far from P. multiseries, P. punges, and P. subfraudulenta. These results imply that ITS2 region is expected to support a useful molecular characters for recognizing at the species level and for even discriminating P. multiseries from P. pungens. RAPD method also will be used to differentiate the species of Pseudo-nitzschia in a short time.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.2
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• pp.87-96
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• 2012

With a view to determine a safe speed the limit of a manipulator arm, several experiments was performed with a multi-jointed manipulator in maintenance and decommissioning tasks of nuclear facilities. Under the simulated emergency conditions, which were generated with random combinations of manipulator arm speed, failure probability and failure type, response characteristics of human operators to various malfunctions of a manipulator arm were measured in terms of reaction time, number of false alarm, and number of misses. This paper demonstrated that failure type, manipulator axes and manipulator arm speed has significant effects on human reaction time. As a whole the reaction time was slightly increased with manipulator arm speed, which is showed somewhat different pattern due to failure type. The reaction time to an axis acting on a workpiece directly, which could flex and extend, was fastest and much more its standard deviation was small. Various factors which may affect safe speed were also described.

• Archives of Plastic Surgery
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• v.36 no.6
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• pp.720-726
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• 2009

Purpose: Fasciocutaneous flap with random pattern flap has limitation in mobility and length - width ratio. This characteristic is more pronounced in lower extremity which has relatively poor vascularity. Perforator based flap in lower extremity reconstruction has various advantages as a axial flap, allowing abundant blood supply and widening of mobility range. So if it is not a case of wide defect, free flap can be replaced by perforator based flap. Methods: From April 2007 to March 2009, 18 cases of perforator flap were performed. 8 had defect in upper 1/3 of calf, 6 in middle 1/3, and 4 in lower 1/3. In 10 cases island flap were used, 3 case had transposition flap, 2 cases used advancement flap, 2 case had propeller flap and 1 case had rotation flap. Results: 17 cases survived without flap necrosis. Partial flap necrosis occurred in 1 case, so secondary split thickness skin graft was done. Chronic wound with pseudomonas infection occurred in 1 case, but it was completely cured with conservative treatment. Conclusion: Perforator based flap is useful in lower extremity reconstruction because of relative freedom in changing the size and thickness of the flap depending on the recipient site, good mobility, and abundant vascularity. And donor site morbidity can be minimized. Lower extremity reconstruction using perforator based flap is a good method because it can minimize the complication and obtain effective result.

• The Journal of Korean Physical Therapy
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• v.32 no.4
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• pp.228-232
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• 2020

Purpose: This study examined the electromyography (EMG) activity of the abdominal muscles and the ratio of the oblique abdominal muscle activity to the rectus abdominis muscle during a single-leg holding position with isometric shoulder abduction (SLHISA) in the supine position on a foam roller. Methods: Nineteen healthy males were recruited to the study. Each subject was asked to lay on a round foam roller and perform singleleg (nondominant) holding with contralateral shoulder abduction to one of three angles (45°, 90°, or 135°) in random order. The surface EMG signals of the bilateral rectus abdominis (RA), external oblique abdominis (EO), and combined internal oblique abdominis (IO) and transverse abdominis (TrA) muscle were collected during the tasks. The EO/RA and (IO & TrA)/RA ratios were determined using surface EMG. One way repeated measure ANOVA with three SLHISAs was used to assess the significant abdominal muscle EMG activity and the ratio of the oblique abdominal muscles activity to the RA muscle. The statistical significance level was p<0.05. Results: The results were as follows. The SLHISA 135° showed significantly higher EMG activity of both RAs, left EO, and right IO & TrA muscles (p<0.05). The right EO and left IO and TrA muscles/RA were significantly different among the SLHISA angles. The SLHISA 45° showed a significantly greater ratio of right EO/RA and left IO & TrA/RA (p<0.05). Conclusion: SLHISA on a foam roller is useful for lumbopelvic stabilization exercise by increasing the activity and recruiting a specific pattern of the oblique abdominal muscle.

• Journal of Fashion Business
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• v.5 no.3
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• pp.9-18
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• 2001

This study is to provide basic data for the development of domestic ready-made shoes industry by illustrating any problem in regards to the ready-made shoes for ordinary salary men through looking into its uses and gratifications. Subjects for this study were in between twenties and sixties by applying convenient random sampling method, which was done in January to February, 2001. The results were as follows: 1. General foot shape of subjects was that foot breadth was wide whereas instep height was average. In regards to the metamorphic parts of foot, the most metamorphic part was the fifth toe which could be occurred by disagreeable shoes to foot. 2. General salary men (69.5%) wear the formal shoes and their wearing time per day is over 10 hours (49%), which illustrates that more suitable and convenient functional shoes needs to be developed. 3. Almost of subjects tended to purchase ready-made shoes, and their concerns to be considered when to purchase ready-made shoes were its size and solidity. This finding suggests that the size specification of the ready-made shoes needs to be more specific in terms of its length as well as foot breadth. 4. The most unsatisfied point on the ready-made shoes was the foot breadth. According to the Crosstabulation analysis on the discomfort part and the foot breadth, there existed a significant correlation between the discomfort part and the foot breadth (p$\leq$0.05). The above results make clear that overall salary men have complaints on the ready-made formal shoes in terms of its size and wearing comfort level. This suggests that the subdivision of the shoes size specification needs to be developed to improve the wearing comfort level.

• Journal of Life Science
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• v.8 no.1
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• pp.8-13
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• 1998

The maize mitochondrial mutant (NCS2) is derived from homologous recombination between genes encoding NADH dehydrogenase subunit 4 and subunit 6. Plants from mitochondria mutants exhibited severe related growth and development including dwarfism and striping on the leaves. Aborted embryos from NCS2 mutants have been rescued and cultured on the N6 medium supplemented with 2,4-D 1 mg/l. Most calli from NCS2 aborted embryos showed slow growing pattern at first stage. However, upon continuous culturing them on the medium, those were segregated into mutant and normal callus lines. These segregations could be detected by using PCR method with three primers. Such segregation seems to be resulted from the preferential growth of normal cells over the mutant cells on the normal culture condition. Therefore, this method can be used for determining rate of indirect cytoplasmic segregation by estimating amplified band intensities. When NCS2 mutant callus lines cultured on regeneration medium, no adventitious shoot induction was observed. However, callus lines with more mitochondria induced adventitious shoots. These studies suggest that mitochondria NADH-dehydrogenase for electron transport in the inner membrane of mitochondria is essential for the differentiation and development of plants.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.379-385
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• 1991

Morphological changes of starch granules from 12 different varieties of rice were examined by scanning electron microscopy during heating at 2.5% (w/v) concentration. Rice starch granules proceeded through a similar pattern of progressive morphological changes daring heating, regardless of variety. Rice starch granules began to swell radially in the initial stage of gelatinization and then undergo radial contraction and random tangential expansion to form complex structures in the latter stage of gelatinization temperature range. At higher temperatures, starch granules softened and melted into thin flat discs, and then stretched into thin filaments to form three-dimensional networks. These progressive morphological changes were reflected in the changes of swelling power, solubility and amylograph viscosity of starch. During the transition of melting or softening, swelling power, solubility and amylograph viscosity increased rapidly. The time of loss of granular structure of starch depended on gelatinization temperature range. The ratio of amylose to amylopectin was largely responsible fur the rate of melting or softening and the fineness of a three-dimensional filamentous network above the gelatinization temperature range. Therefore, both the gelatinization temperature range and amylose content of starch affect the rate of cooking, and amylose content of starch affects the final texture of cooked starch paste.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.1881-1900
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• 2014

Since 802.11 wireless LANs are so widely used, it has become common for numerous access points (APs) to overlap in a region, where most of those APs are managed individually without any coordinated control. This pattern of wireless LAN usage is called the private OBSS (Overlapping Basic Service Set) environment in this paper. Due to frame collisions across BSSs, each BSS in the private OBSS environment suffers severe performance degradation. This study approaches the problem from the perspective of congestion control rather than noise or collision resolution. The retry limit, one of the 802.11 attributes, could be used for traffic control in conjunction with TCP. Reducing the retry limit causes early discard of a frame, and it has a similar effect of random early drops at a router, well known in the research area of congestion control. It makes the shared link less crowded with frames, and then the benefit of fewer collisions surpasses the penalty of less strict error recovery. As a result, the network-wide performance improves and so does the performance of each BSS eventually. Reducing the retry limit also has positive effects of merging TCP ACKs and reducing HOL-like blocking time at the AP. Extensive experiments have validated the idea that in the OBSS environment, reducing the retry limit provides better performance, which is contrary to the common wisdom. Since our strategy is basically to sacrifice error recovery for congestion control, it could yield side-effects in an environment where the cost of error recovery is high. Therefore, to be useful in general network and traffic environments, adaptability is required. To prove the feasibility of the adaptive scheme, a simple method to dynamically adjust the value of the retry limit has been proposed. Experiments have shown that this approach could provide comparable performance in unfriendly environments.