• 한국해양공학회지
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• 제12권3호통권29호
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• pp.86-95
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• 1998

CAD/CAM program developers have made substantial progress in enabling engineers to design, analyze, visualize, visualize, and simulate the performance of structures and systems. Many researchers, however, agree that there is still a way to go before the existing commercial computer software can be used in ship structural analysis to their full potential as solvers which can identify opportunities to reduce man-hours and cut costs. CAD systems used for these works in ship yards are general-purposed and not custom-tailored for ship structures, which force end-users to do tiresome and routine works. The new preprocessor "MeshGen" announced in this study can load several ship types and user-friendly generate their FE meshes employing the object-oriented approach based on the parametric and top-down design. Also "MeshGen" reduces dramatically the time required to prepare CAD models under window-based environments on desktop personal computers and makes it much easier and faster for end-users to change topology and material properties.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 추계학술발표대회
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• pp.842-845
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• 2020

본 연구는 시각-관성 기반의 딥러닝 학습으로 자유분방하게 움직이는 드론의 주행기록을 정확하게 추정하는 것을 목표로 한다. 드론의 비행주행은 드론의 온보드 센서와 조정값을 이용하는 것이 일반적이다. 본 연구에서는 이 온보드 센서 데이터를 학습에 사용하여 비행주행의 위치추정을 실험하였다. 선행연구로써 DeepVO[1]룰 구현하여 KITTI[3] 데이터와 Midair[4] 데이터를 비교, 분석하였다. 3D 좌표면에서의 위치 추정에 선행연구 모델의 한계가 있음을 확인하고 IMU를 Feature로써 사용하였다. 본 모델은 FlowNet[2]을 모방한 CNN 네트워크로부터 Optical Flow Feature에 IMU 데이터를 더해 RNN으로 학습을 진행하였다. 본 연구를 통해 주행기록 예측을 다소 정확히 했다고 할 수 없지만, IMU Feature를 통해 주행기록의 예측이 가능함을 볼 수 있었다. 본 연구를 통해 시각-관성 분야에서 사람의 지식이나 조정이 들어가는 센서를 융합하는 기존의 방식에서 사람의 제어가 들어가지 않는 End-to-End 방식으로 인공지능을 학습했다. 또한, 시각과 관성 데이터를 통해 주행기록을 추정할 수 있었고 시각적으로 그래프를 그려 정답과 얼마나 차이 있는지 확인해보았다.

• Biomolecules & Therapeutics
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• 제11권3호
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• pp.178-182
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• 2003

The clinical use of once daily aminoglycoside (ODA) dosing has been increased because of the potential therapeutic advantages of this dosing regimen. To evaluate the optimal sampling times of ODA dosing method in a clinical setting, the study was prospectively conducted in a total of 28 patients with UTI. All of the patients were intravenously administered gentamicin at a dose of 7 mg/kg over 60 minutes and randomly divided into two groups. Blood was collected at 0, 2, and 6 hours in Group A and at 1, 2, and 6 hours in Group B after the end of 1-hour infusion. The pharmacokinetic parameters (Ke, Vd and Cmax) obtained using the 0, 6 hour levels and 2, 6 hour levels in Group A were statistically different while those of 1, 6 hour levels and 2, 6 hour levels in Group B were similar. This finding indicated that the distributional phase of ODA is completed within 1 hour following the end of the I-hour infusion. If we are allowed to collect only two blood samples in ODA considering patients comfort and the analytical cost of drug, the first one should be drawn after 1 hour following the end of infusion to obtain adequate pharmacokinetic information.

• Journal of Korean Neurosurgical Society
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• 제59권3호
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• pp.259-268
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• 2016

Objective : Accumulation of advanced glycation end-products (AGE) and mitochondrial glycation is importantly implicated in the pathological changes of the brain associated with diabetic complications, Alzheimer disease, and aging. The present study was undertaken to determine whether sildenafil, a type 5 phosphodiesterase type (PDE-5) inhibitor, has beneficial effect on neuronal cells challenged with AGE-induced oxidative stress to preserve their mitochondrial functional integrity. Methods : HT-22 hippocampal neuronal cells were exposed to AGE and changes in the mitochondrial functional parameters were determined. Pretreatment of cells with sildenafil effectively ameliorated these AGE-induced deterioration of mitochondrial functional integrity. Results : AGE-treated cells lost their mitochondrial functional integrity which was estimated by their MTT reduction ability and intracellular ATP concentration. These cells exhibited stimulated generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential, induction of mitochondrial permeability transition, and release of the cytochrome C, activation of the caspase-3 accompanied by apoptosis. Western blot analyses and qRT-PCR demonstrated that sildenafil increased the expression level of the heme oxygenase-1 (HO-1). CoPP and bilirubin, an inducer of HO-1 and a metabolic product of HO-1, respectively, provided a similar protective effects. On the contrary, the HO-1 inhibitor ZnPP IX blocked the effect of sildenafil. Transfection with HO-1 siRNA significantly reduced the protective effect of sildenafil on the loss of MTT reduction ability and MPT induction in AGE-treated cells. Conclusion : Taken together, our results suggested that sildenafil provides beneficial effect to protect the HT-22 hippocampal neuronal cells against AGE-induced deterioration of mitochondrial integrity, and upregulation of HO-1 is involved in the underlying mechanism.

• Macromolecular Research
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• 제15권4호
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• pp.337-342
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• 2007

The n-butyllithium-initiated ring-opening polymerization of ethylene oxide, in a mixture of benzene and dimethylsulfoxide (DMSO), between $25-45^{\circ}C$, with potassium tert-butoxide, is a useful and powerful method to control the molecular weight as well as achieve a quantitative chain-end functionalization yield of the resulting polymeric alkoxide via a one pot synthesis. The molecular weight of the product could be controlled by adjusting the ratio of grams of monomer to moles of initiators, such as n-butyllithium ([n-BuLi]) and potassium t-butoxide ([t-BuOK]). The yields for the macromonomer and ${\omega}-brominated$ poly(ethylene oxide) (PEO) were quantitative in relation to the chain-end functionalizations of the polymeric alkoxide formed. The resulting products were characterized by a combination of $^1H-NMR$ spectroscopic and size exclusion chromatographic analyses.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.105-111
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• 2005

End-stage renal disease is a fatal and devastating disease that is caused by progressive and irreversible loss of functioning nephrons in the kidney. Dialysis and renal transplantation are the common treatments at present, but these treatments have severe limitations. The present study investigated the possibility of reconstructing renal tissues by transplantation of renal precursor cells to replace the current treatments for end-stage renal disease. Embryonic renal precursor cells, freshly isolated from metanephroi of rat fetus at day 15 post-gestation, were seeded on biodegradable polymer scaffolds and transplanted into peritoneal cavities of athymic mice for three weeks. Histologic sections stained with hematoxylin & eosin and periodic acid-Schiff revealed the formation of primitive glomeruli, tubules, and blood vessels, suggesting the potential of embryonic renal precursor cells to reconstitute renal tissues. Immunohistochemical staining for proliferating cell nuclear antigen, a marker of proliferating cells, showed intensive nuclear expression in the regenerated renal structures, suggesting renal tissue reconstitution by transplanted embryonic renal precursor cells. This study demonstrates the reconstitution of renal tissue in vivo by transplanting renal precursor cells with biodegradable polymer scaffolds, which could be utilized as a new method for partial or full restoration of renal structure and function in the treatment of end-stage renal disease.

• Advances in pediatric surgery
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• 제13권1호
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• pp.23-29
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• 2007

Tapering enteroplasty was first described by Thomas in 1969 as one method of intestinal anastomosis. The advantages of tapering enteroplasty in the intestinal atresia are: First, it makes end-to-end anastomosis possible between the atretic bowel ends with considerable differences in diameters. Second, it promotes the recover of the postoperative bowel function. Third, it prevents the possibility of the short bowel syndrome by eliminating the need of resecting the dilated bowel. A total of 22 patients with intestinal atresia who underwent tapering enteroplasty from January 1988 to December 2005 at our institute were reviewed. In 3 of 22 cases, tapering enteroplasty was the $2^{nd}$ operation after an initial end-to-oblique anastomosis. We reviewed the following items: age, sex, type and location of intestinal atresia, initial feeding and total enteral feeding start day, the length of hospital stay and complications. The average age of the patients was 7 days. Male to female ratio was 1 to 1.2 (10 cases: 12 cases). We performed the tapering enteroplasty on all types and locations of the intestinal atresia from the duodenum to the colon: type I (n=3), type II (n=4), type IIIA (n=7), type IIIB (n=5), type IIIB and IV (n=1), type IV (n=1) and type C (duodenum) and type IIIB and IV (jejunum). On the average, the oral feeds were started on the postoperative $8.8^{th}$ day, and full caloric intake via the enteric route was achieved on postoperative $13.3^{th}$ day. The average length of hospital stay was 19.6 days. There were 1 case (4.5 %) of anastomotic complication and 2 cases (9 %) of adhesive ileus among 22 patients. The tapering enteroplasty on all types of intestinal atresia is a usefull operative method when there are considerable diameter differences between the atretic bowel ends.

• Current Optics and Photonics
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• 제5권3호
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• pp.250-260
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• 2021

A tapered As₂S₃ photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As₂S₃ PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 ㎛ propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As₂S₃ PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.

• Molecules and Cells
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• 제22권2호
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• pp.146-153
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• 2006

Cell polarity is critical for the division, differentiation, migration, and signaling of eukaryotic cells. RAX2 of budding yeast encodes a membrane protein localized at the cell cortex that helps maintain the polarity of the bipolar pattern. Here, we designate SPAC6f6.06c as $rax2^+$ of Schizosaccharomyces pombe, based on its sequence homology with RAX2, and examine its function in cell polarity. S. pombe $rax2^+$ is not essential, but ${\Delta}rax2$ cells are slightly smaller and grow slower than wild type cells. During vegetative growth or arrest at G1 by mutation of cdc10, deletion of $rax2^+$ increases the number of cells failing old end growth just after division. In addition, this failure of old end growth is dramatically increased in ${\Delta}tea1{\Delta}rax2$, pointing to genetic interaction of $rax2^+$ with $tea1^+$. ${\Delta}rax2$ cells contain normal actin and microtubule cytoskeletons, but lack actin cables, and the polarity factor for3p is not properly localized at the growing tip. In ${\Delta}rax2$ cells, and endogenous rax2p is localized at the cell cortex of growing cell tips in an actin- and microtubule-dependent manner. However, ${\Delta}rax2$ cells show no defects in cell polarity during shmoo formation and conjugation. Taken together, these observations suggest that rax2p controls the cell polarity of fission yeast during vegetative growth by regulating for3p localization.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권1호
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• pp.11-16
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• 2014

Objectives: The aim of this study was to evaluate the pattern of lingual split line when performing a bilateral sagittal split osteotomy (BSSO) for asymmetric prognathism. This was accomplished with the use of cone-beam computed tomography (CBCT) and three-dimensional (3D) software program. Materials and Methods: The study group was comprised of 40 patients (20 males and 20 females) with asymmetric prognathism, who underwent BSSO (80 splits; n=80) from January 2012 through June 2013. We observed the pattern of lingual split line using CBCT data and image analysis program. The deviated side was compared to the contralateral side in each patient. To analyze the contributing factors to the split pattern, we observed the position of the lateral cortical bone cut end and measured the thickness of the ramus that surrounds the mandibular lingula. Results: The lingual split patterns were classified into five types. The true "Hunsuck" line was 60.00% (n=48), and the bad split was 7.50% (n=6). Ramal thickness surrounding the lingual was $5.55{\pm}1.07$ mm (deviated) and $5.66{\pm}1.34$ mm (contralateral) (P =0.409). The position of the lateral cortical bone cut end was classified into three types: A, lingual; B, inferior; C, buccal. Type A comprised 66.25% (n=53), Type B comprised 22.50% (n=18), and Type C comprised 11.25% (n=9). Conclusion: In asymmetric prognathism patients, there were no differences in the ramal thickness between the deviated side and the contralateral side. Furthermore, no differences were found in the lingual split pattern. The lingual split pattern correlated with the position of the lateral cortical bone cut end. In addition, the 3D-CT reformation was a useful tool for evaluating the surgical results of BSSO of the mandible.