• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.215-220
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• 2002

The structures of 1-fluorosilatrane and the silatranyl cation were calculated by Hartree-Fock (HF), Mofller-Plesset second order (MP2), and various density functional theory (DFT) methods using many different basis sets, demonstrating that the Si-N bonds in two species are quite different. The N${\rightarrow}$Si bond distance of 1-fluorosilatrane from the hybrid DFT calculations $({\sim}2.32{\AA})$ using the Perdew-Wang correlation functional agrees with the gas phase experimental value $(2.324{\AA})$, while other functionals yield larger distances. The MP2 bond distance (2.287${\AA}$ with 6-311$G^{\ast}$) is shorter, and the HF one (2.544 ${\AA}$ with 6-311$G^{\ast}$) larger than those of DFT calculations. The MP2 bond distance is in good agreement with experiment indicating that the electron correlations are crucial for the correct description of the N${\rightarrow}$Si interaction. The silatranyl cation is a stable local minimum on the potential energy surface in all methods employed suggesting that the cation could be a reaction intermediate. The Si-N bond length for the cation is about 1.87 ${\AA}$ for all calculations tested implying that the Si-N bond is mainly conventional. Bonding characteristics of the Si-N bond in two species derived from the natural bond orbital analysis support the above argument based on calculated bond lengths.

• Structural Monitoring and Maintenance
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• v.1 no.2
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• pp.183-195
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• 2014

Scour is one of the leading causes of overwater bridge failures worldwide. While monitoring systems have already been implemented or are still being developed, they suffer from limitations such as high costs, inaccuracies, and low reliability, among others. Also, most sensors only measure scour depth at one location and near the pier. Thus, the objective is to design a simple, low cost, scour hole topography monitoring system that could better characterize the entire depth, shape, and size of bridge scour holes. The design is based on burying a robust, waterproofed, piezoelectric sensor strip in the streambed. When scour erodes sediments to expose the sensor, flowing water excites it to cause the generation of time-varying voltage signals. An algorithm then takes the time-domain data and maps it to the frequency-domain for identifying the sensor's resonant frequency, which is used for calculating the exposed sensor length or scour depth. Here, three different sets of tests were conducted to validate this new technique. First, a single sensor was tested in ambient air, and its exposed length was varied. Upon verifying the sensing concept, a waterproofed prototype was buried in soil and tested in a tank filled with water. Sensor performance was characterized as soil was manually eroded away, which simulated various scour depths. The results confirmed that sensor resonant frequencies decreased with increasing scour depths. Finally, a network of 11 sensors was configured to form a distributed monitoring system in the lab. Their exposed lengths were adjusted to simulate scour hole formation and evolution. Results showed promise that the proposed sensing system could be scaled up and used for bridge scour topography monitoring.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.939-944
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• 2016

Background: Cell-free DNA circulating in blood is a candidate biomarker for malignant tumors. Unlike uniformly truncated DNA released from apoptotic non diseased cells, DNA released from necrotic cancer cells varies in size. Objectives: To measure the DNA integrity index in serum and the absolute DNA concentration to assess their clinical utility as potential serum biomarkers for colorectal carcinoma (CRC) compared to CEA and CA19-9. Materials and Methods: Fifty patients with CRC, 10 with benign colonic polyps and 20 healthy sex and age matched volunteers, were investigated by real time PCR of ALU repeats (ALU q-PCR) using two sets of primers (115 and 247 bp) amplifying different lengths of DNA fragments. The DNA integrity index was calculated as the ratio of q-PCR results of ALU 247/ALU 115bp. Results: Serum DNA integrity was statistically significantly higher in CRC patients compared to the benign and control groups (p<0.001). ROC curves for differentiating CRC patients from normal controls and benign groups had areas under curves of 0.90 and 0.85 respectively. Conclusions: The DNA integrity index is superior to the absolute DNA concentration as a potential serum biomarker for screening and diagnosis of CRC. It may also serve as an indicator for monitoring the progression of CRC patients. Combining CEA and CA19-9 with either of the genetic markers studied is better than either of them alone.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.222-227
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• 1997

To diagnose cardiac arrhythmia owing to reentry mechanism, cardiac conduction system was modeled by modified Hidden Markov modeled by evaluated. First, simulation of transient conduction states and output waves were made with initially assumed parametric values of cardiac muscle repolariztion time, conduction velocity and its automaticity. The output was a series of onset time and the name of the wave. Parameters determined the rate of beating, lengths of wave intervals, rate of abnormal beats, and the like. Several parameter sets were found to simulate normal sinus rhythm, supraventricular /ventricular tachycardia, atrial /vetricular extrasystole, etc. Then, utilizing the estimation theorems of Hidden Markov Model, the best conduction path was estimated given the previous output. With this modified estimation method, close matching between the simulated conduction path and the estimated one was confirmed.

• Journal of Korean Society of Steel Construction
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• v.12 no.3 s.46
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• pp.259-268
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• 2000

In the friction-type joints the external applied load is transmitted by frictional force acting on the contact area of the plates fastened by the high strength bolts. This frictional force is proportional to the product of the bolt clamping force and slip coefficient of the faying surface. But the bolt clamping force is dependent on many factors when the turn-of-nut method is used. The preserved thread length and length-to-diameter ratios are one of the major factors governing the bolt clamping force. This paper presents the correct method of high strength bolt tightening through the experiment on the mechanical properties on sets of high strength bolts in accordance with preserved thread length and length-to-diameter ratios.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.225-230
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• 2009

Sex-sorting of sperm is an assisted reproductive technology (ART) used by the livestock industry for the mass production of animals of a desired sex. The standard method for sorting sperm is the detection of DNA content differences between X and Y chromosome-bearing sperm by flow cytometry. However, this method has variable efficiency and therefore requires verification by a second method. We have developed a sex determination method based on quantitative real-time polymerase chain reaction (qPCR) of the porcine amelogenin (AMEL) gene. The AMEL gene is present on both the X and the Y chromosome, but the length and sequence of its noncoding regions differ between the X and Y chromosomes. By measuring the threshold cycle (Ct) of qPCR, we were able to calculate the relative frequency of X chromosome. Two sets of AMEL primers were used in these studies. One set (AME) targeted AMEL gene sequences present in both X and Y chromosome, but produced PCR products of different lengths for each chromosome. The other set (AXR) bound to AMEL gene sequences present on the X chromosome but absent esholthe Y-chromosome. Relative product levels were calculated by normalizing the AXR fluorescence to the AME fluorescence. The AMEL method accurately predicted the sex ratios of boar sperm, demonstrating that it has potential value as a sex determination method.

• Structural Engineering and Mechanics
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• v.83 no.4
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• pp.495-513
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• 2022

This paper aims to study the fracture mechanism of rocks under the 'u'shape cutters considering the effects of crack (pre-existing crack) distances, crack spacing and crack inclination angles. The effects of loading rates on the rock fragmentation underneath these cutters have been also studied. For this purpose, nine experimental samples with dimensions of 5 cm×10 cm×10 cm consisting of the non-persistent cracks were prepared. The first three specimens' sets had one non-persistent crack (pre-existing crack) with a length of 2 cm and angularity of 0°, 45°, and 90°. The spacing between the crack and the "u" shape cutter was 2 cm. The second three specimens" set had one non-persistent crack with a length of 2 cm and angularity of 0°, 45°, and 90° but the spacing between pre-existing crack and the "u" shape cutter was 4 cm. The third three specimens'set has two non-persistent cracks with lengths of 2 cm and angularity of 0°, 45° and 90°. The spacing between the upper crack and the "u" shape cutter was 2 cm and the spacing between the lower crack and the upper crack was 2 cm. The samples were tested under a loading rate of 0.005 mm/s. concurrent with the experimental investigation. The numerical simulations were performed on the modeled samples with non-persistent cracks using PFC2D. These models were tested under three different loading rates of 0.005 mm/s, 0.01 mm/sec and 0.02 mm/sec. These results show that the crack number, crack spacing, crack angularity, and loading rate has important effects on the crack growth mechanism in the rocks underneath the "u" shape cutters. In addition, the failure modes and the fracture patterns in the experimental tests and numerical simulations are similar to one another showing the validity and accuracy of the current study.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.165-172
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• 2013

This study was conducted to investigate the effect of bulblet size on growth and bulb enlargement of Lilium Oriental hybrids, such as 'Sorbonne', 'Siberia', and 'Casa Blanca', grown in areas of high altitude (780 m), in 2009. The bulblets were oriented from tissue culture and planted to produce virus-free bulblets. All the three cultivars showed high vitality, with more than 93% producing shoots, even from small bulblets with a bulb circumference (BC) of less than 6 cm. Bulblets with BC 9-10 cm showed an increased height and number of leaves rapidly to induce the phase conversation from vegetative growth to reproductive growth. The bulblets of BC 9-10 cm in 'Sorbonne', 'Siberia', and 'Casa Blanca' had 2.0, 2.9, and 2.8 flower bud sets per plant, respectively. However, the flowers from those bulblets were not adequate as standard bulbs to produce cut-flowers for the domestic market. The larger bulblets showed more prosperous characteristics in growth and development of Lilium Oriental hybrids. Small bulblets had a high occurrence of viruses and leaf blight symptoms during cultivation, indicating the aggravated disease symptoms in the previously infected bulbs. 'Sorbonne' cultivars showed a high rate of enlargement of bulbs, and small bulblets under BC 6 cm produced more than 23% of the standard bulbs of BC 14-16 cm, which could produce cut-flowers for export. However, 'Casa Blanca' bulblets with BC 6-9 cm produced low bulbs of BC 14-16 cm at 21% level. 'Casa Blanca' cultivars had more bulb roots, longer root lengths, and higher weights than 'Sorbonne' and 'Siberia' cultivars. 'Casa Blanca' cultivars with BC over 9-10 cm grew rapidly and produced a high quantity of bulbs. In these results, 'Sorbonne' bulblets of BC 9-10, 'Siberia' bulblets of BC 10-12 cm, and 'Casa Blanca' bulblets of BC 10-12 cm produced 89%, 86%, and 93% of the standard bulbs of BC 14-16 cm, respectively. It is recommended that bulblets larger than the above sizes be used to produce cut-flowers for the export market. Experiment results suggest that production of bulbs larger than BC 18 cm requires bulblets that are larger than BC 12-14 cm of the three cultivars for the highest quality cut-flowers.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.305-312
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• 2023

Objective: Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a recently recognized disease. We aimed to evaluate the enterographic findings of CEAS. Materials and Methods: Altogether, 14 patients with CEAS were confirmed based on known SLCO2A1 mutations. They were registered in a multicenter Korean registry between July 2018 and July 2021. Nine of the patients (37.2 ± 13 years; all female) who underwent surgery-naïve-state computed tomography enterography (CTE) or magnetic resonance enterography (MRE) were identified. Two experienced radiologists reviewed 25 and 2 sets of CTE and MRE examinations, respectively, regarding the small bowel findings. Results: In initial evaluation, eight patients showed a total of 37 areas with mural abnormalities in the ileum on CTE, including 1-4 segments in six and > 10 segments in two patients. One patient showed unremarkable CTE. The involved segments were 10-85 mm (median, 20 mm) in length, 3-14 mm (median, 7 mm) in mural thickness, circumferential in 86.5% (32/37), and showed stratified enhancement in the enteric and portal phases in 91.9% (34/37) and 81.8% (9/11), respectively. Perienteric infiltration and prominent vasa recta were noted in 2.7% (1/37) and 13.5% (5/37), respectively. Bowel strictures were identified in six patients (66.7%), with a maximum upstream diameter of 31-48 mm. Two patients underwent surgery for strictures immediately after the initial enterography. Follow-up CTE and MRE in the remaining patients showed minimal-to-mild changes in the extent and thickness of the mural involvement for 17-138 months (median, 47.5 months) after initial enterography. Two patients required surgery for bowel stricture at 19 and 38 months of follow-up, respectively. Conclusion: CEAS of the small bowel typically manifested on enterography in varying numbers and lengths of abnormal ileal segments that showed circumferential mural thickening with layered enhancement without perienteric abnormalities. The lesions caused bowel strictures that required surgery in some patients.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.1-11
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• 2014

To compare the catches made using gillnets, trammel nets, and gillnets with supporting lines, several experiments were conducted with commercial vessels near Uljin and Pohang in Eastern Korea between July 2010 and May 2011. Two sets of 13 different nets were used, including 5 panels of gillnets and trammel nets each with stretched mesh sizes of 7.6, 9.1, 10.6, 12.1, and 13.6 cm and 3 panels of gillnets with a mesh size of 9.1 cm with supporting lines with different line spacing. The outer (stretched) mesh size of the trammel nets measured 51.5 cm. The target fishes of the fishing nets were various types of flounders. The catch rate of flounders was 50.7% of the total catch in weight. The total catch for all nets was 443.8 kg. The predominant species was pointhead flounder (Cleisthenes pinetorum). The total catch by trammel nets was 1.4 times that of the comparable gillnets. But more pointhead flounder were caught by gillnets than by trammel nets, though there was no significant difference. Fishermen catching the pointhead flounder in Korea said that there was no need to use trammel net to catch it; this was an unexpected finding compared to the findings of other flounder fisheries. The amounts of roughscale sole, brown sole, and blackfin flounder caught by trammel nets were greater than those caught by gillnets. The mean lengths (standard deviation) of blackfin flounder, pointhead flounder, brown sole, and roughscale sole were 21.0 (4.57), 22.9 (3.40), 24.7 (4.90), and 28.3 (5.43) cm, respectively; there were significant differences in mean length (p < 0.00001). Therefore, in order to catch flounder efficiently, the fishing nets and mesh size should be chosen according to the target species. One advantage of using supporting lines is that it prevents breakage by strengthening the material especially when utilized on a rough bottom. Catch by using gillnet with supporting lines was not greater than that by using trammel net for the conservation of fisheries resources.