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Search Results: 1 - 10 of 19179 matches for " Hyuk Song "
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Evaluation of the relationship between dietary factors, CagA-positive Helicobacter pylori infection, and RUNX3 promoter hypermethylation in gastric cancer tissue
Yan-Wei Zhang,Sang-Yong Eom,Dong-Hyuk Yim,Young-Jin Song
World Journal of Gastroenterology , 2013, DOI: 10.3748/wjg.v19.i11.1778
Abstract: AIM: To evaluate the relationship among Helicobacter pylori (H. pylori) infection, CagA status, and dietary factors with RUNX3 promoter hypermethylation. METHODS: Gastric cancer tissue samples were collected from 184 South Korean patients. All patients were interviewed following a semi-quantitative food frequency questionnaire. The average frequencies of intake and portion sizes of 89 common food items were documented, and total intakes of calories, nutrients, vitamins, and minerals were calculated for each subject. DNA was extracted from gastric cancer tissue samples, and amplification of the HSP60 gene was performed to detect H. pylori infection. Nested polymerase chain reaction (PCR) was used to detect the presence of the CagA gene. RUNX3 gene expression was measured by reverse transcription-PCR, and RUNX3 methylation status was evaluated by methylation-specific PCR. The odds ratios (ORs) and 95%CI associated with RUNX3 promoter hypermethylation status were estimated for each of the food groups, lifestyle factors, and the interaction between dietary and lifestyle factors with CagA status of H. pylori infection. RESULTS: Overall, 164 patients (89.1%) were positive for H. pylori DNA, with the CagA gene detected in 59 (36%) of these H. pylori-positive samples. In all, 106 (57.6%) patients with gastric cancer demonstrated CpG island hypermethylation at the RUNX3 promoter. RUNX3 expression was undetectable in 52 (43.7%) of the 119 gastric cancer tissues sampled. A high consumption of eggs may increase the risk of RUNX3 methylation in gastric cancer patients, having a mean OR of 2.15 (range, 1.14-4.08). A significantly increased OR of 4.28 (range, 1.19-15.49) was observed with a high consumption of nuts in patients with CagA-positive H. pylori infection. High intakes of carbohydrate, vitamin B1, and vitamin E may decrease the risk of RUNX3 methylation in gastric cancer tissue, particularly in CagA- or H. pylori-negative infection, with OR of 0.41 (0.19-0.90), 0.42 (0.20-0.89), and 0.29 (0.13-0.62), respectively. A high consumption of fruits may protect against RUNX3 methylation. CONCLUSION: These results suggest that the CagA status of H. pylori infection may be a modifier of dietary effects on RUNX3 methylation in gastric cancer tissue.
Directional terahertz emission from diffusion-engineered InAs structures
Jong-Hyuk Yim,Hoonil Jeong,Jin-Dong Song,Young-Dahl Jho
Physics , 2012, DOI: 10.1364/OE.21.019709
Abstract: We have designed and fabricated a new type of terahertz (THz) emitter that radiates THz waves along the surface-normal direction because of the lateral distributions of the transient electric dipoles. The excitation and measurements were performed using a conventional THz time-domain spectroscopy scheme with femtosecond optical pulses. The corrugated mirror patterns on the InAs layers made the radiation directional along the surface-normal direction, and the emission efficiency was controlled by adjustment of the pattern width.
Nexus between directionality of THz waves and structural parameters in groove-patterned InAs
Jong-Hyuk Yim,Kyunggu Min,Hoonil Jeong,Jin-Dong Song,Young-Dahl Jho
Physics , 2012, DOI: 10.1063/1.4795541
Abstract: We have performed terahertz (THz)-time domain spectroscopy in various geometries, for characterizing the directivity of THz waves emitted from groove-patterned InAs structures. First, we have distinguished the THz emission mechanisms as a function of epilayer thickness. The carrier drift was predominant in thin sample group (10-70 nm) which the electronic diffusion motion was overriding the oppositely aligned drifting dipoles in thick sample group (370-900 nm) as revealed via amplitude and phase variations. By combined use of the electron-beam lithography and the inductively coupled plasma etching in 1 {\mu}m-thick InAs epilayers, we have further fabricated either asymmetric V-groove patterns or symmetric parabolic patterns. The THz amplitude was enhanced, particularly along line-of-sight transmissive direction when the groove patterns act as microscale reflective mirrors periodically separated by a scale of diffusion length.
Odysseus/DFS: Integration of DBMS and Distributed File System for Transaction Processing of Big Data
Jun-Sung Kim,Kyu-Young Whang,Hyuk-Yoon Kwon,Il-Yeol Song
Computer Science , 2014,
Abstract: The relational DBMS (RDBMS) has been widely used since it supports various high-level functionalities such as SQL, schemas, indexes, and transactions that do not exist in the O/S file system. But, a recent advent of big data technology facilitates development of new systems that sacrifice the DBMS functionality in order to efficiently manage large-scale data. Those so-called NoSQL systems use a distributed file system, which support scalability and reliability. They support scalability of the system by storing data into a large number of low-cost commodity hardware and support reliability by storing the data in replica. However, they have a drawback that they do not adequately support high-level DBMS functionality. In this paper, we propose an architecture of a DBMS that uses the DFS as storage. With this novel architecture, the DBMS is capable of supporting scalability and reliability of the DFS as well as high-level functionality of DBMS. Thus, a DBMS can utilize a virtually unlimited storage space provided by the DFS, rendering it to be suitable for big data analytics. As part of the architecture of the DBMS, we propose the notion of the meta DFS file, which allows the DBMS to use the DFS as the storage, and an efficient transaction management method including recovery and concurrency control. We implement this architecture in Odysseus/DFS, an integration of the Odysseus relational DBMS, that has been being developed at KAIST for over 24 years, with the DFS. Our experiments on transaction processing show that, due to the high-level functionality of Odysseus/DFS, it outperforms Hbase, which is a representative open-source NoSQL system. We also show that, compared with an RDBMS with local storage, the performance of Odysseus/DFS is comparable or marginally degraded, showing that the overhead of Odysseus/DFS for supporting scalability by using the DFS as the storage is not significant.
Treatment of neuromuscular scoliosis with posterior-only pedicle screw fixation
Hitesh N Modi, Seung-Woo Suh, Hae-Ryong Song, Harry M Fernandez, Jae-Hyuk Yang
Journal of Orthopaedic Surgery and Research , 2008, DOI: 10.1186/1749-799x-3-23
Abstract: Between 2003 and 2006, 26 consecutive patients (7 cerebral palsy, 10 Duchenne muscular dystrophy, 5 spinal muscular atrophy and 4 others) with neuromuscular scoliosis underwent posterior pedicle screw fixation for the deformity. Preoperative, immediate postoperative and final follow-up Cobb's angle and pelvic obliquity were analyzed on radiographs. The average age of the patients was 17.5 years (range, 8–44 years) and the average follow-up was 25 months (18–52 months).Average Cobb's angle was 78.53° before surgery, 30.70° after surgery (60.9% correction), and 33.06° at final follow-up (57.9% correction) showing significant correction (p < 0.0001). There were 9 patients with curves more than 90° showed an average pre-operative, post operative and final follow up Cobb's angle 105.67°, 52.33° (50.47% correction) and 53.33° (49.53% correction) respectively and 17 patients with curve less than 90° showed average per operative, post operative and final follow up Cobb's angle 64.18, 19.24(70% correction) and 21.41(66.64 correction); which suggests statistically no significant difference in both groups (p = 0.1284). 7 patients underwent Posterior vertebral column resection due to the presence of a rigid curve. The average spinal-pelvic obliquity was 16.27° before surgery, 8.96° after surgery, and 9.27° at final follow-up exhibited significant correction (p < 0.0001). There was 1 poliomyelitis patient who had power grade 3 in lower limbs pre-operatively, developed grade 2 power post-operatively and gradually improved to the pre-operative stage. There was 1 case of deep wound infection and no case of pseud-arthrosis, instrument failures or mortality.Results indicate that in patients with neuromuscular scoliosis, acceptable amounts of curve correction can be achieved and maintained with posterior-only pedicle screw instrumentation without anterior release procedure.The prevalence of severe spinal deformity in patients with neuromuscular disorders is estimated between 50% and 8
Differential wedging of vertebral body and intervertebral disc in thoracic and lumbar spine in adolescent idiopathic scoliosis – A cross sectional study in 150 patients
Hitesh N Modi, Seung Suh, Hae-Ryong Song, Jae-Hyuk Yang, Hak-Jun Kim, Chetna H Modi
Scoliosis , 2008, DOI: 10.1186/1748-7161-3-11
Abstract: This cross sectional study in 150 patients of adolescent idiopathic scoliosis was done to evaluate vertebral body and disc wedging in scoliosis and to compare the extent of differential wedging of body and disc, in thoracic and lumbar area. We measured wedging of vertebral bodies and discs, along with two adjacent vertebrae and disc, above and below the apex and evaluated them according to severity of curve (curve < 30° and curve > 30°) to find the relationship of vertebral body or disc wedging with scoliosis in thoracic and lumbar spine. We also compared the wedging and rotations of vertebrae.In both thoracic and lumbar curves, we found that greater the degree of scoliosis, greater the wedging in both disc and body and the degree of wedging was more at apex supporting the theory of growth retardation in stress concentration area. However, the degree of wedging in vertebral body is more than the disc in thoracic spine while the wedging was more in disc than body in lumbar spine. On comparing the wedging with the rotation, we did not find any significant relationship suggesting that it has no relation with rotation.From our study, we can conclude that wedging in disc and body are increasing with progression on scoliosis and maximum at apex; however there is differential wedging of body and disc, in thoracic and lumbar area, that is vertebral body wedging is more profound in thoracic area while disc wedging is more profound in lumbar area which possibly form 'vicious cycle' by asymmetric loading to spine for the progression of curve.Scoliosis is a three-dimensional deformity involving coronal, sagittal and axial angulations. Extent of the disease progress, decision to change the treatment strategy and efficacy of the treatment are mainly dependent on the severity in coronal plane angle, commonly known as Cobb's angle as a primary interest. In idiopathic scoliosis, factors responsible for the progression of curve are still unclear and authors have their own point of vi
Intraoperative blood loss during different stages of scoliosis surgery: A prospective study
Hitesh N Modi, Seung-Woo Suh, Jae-Young Hong, Sang-Heon Song, Jae-Hyuk Yang
Scoliosis , 2010, DOI: 10.1186/1748-7161-5-16
Abstract: We prospectively analyzed the estimated blood loss (EBL) and operation time over four stages of scoliosis surgery in 44 patients. The patients were divided into three groups: adolescent idiopathic (group 1), spastic neuromuscular (group 2) and paralytic neuromuscular (group 3). The per-level EBL and operation times of the groups were compared on a stage-by-stage basis. The bone marrow density (BMD) of each patient was also obtained, and the relationship between per-level EBL and BMD was compared using regression analysis.Per-level operation time was similar across all groups during surgical stage (p > 0.05). Per-level EBL was also similar during the dissection and bone-grafting states (p > 0.05). However, during the screw insertion stage, the per-level EBL was significantly higher in groups 2 and 3 compared to group 1 (p < 0.05). In the correction stage, per-level EBL was highest in group 3 (followed in order by groups 2 and 1) (p < 0.05). Preoperative BMD indicated that group 3 had the lowest bone quality, followed by groups 2 and 1 (in order), but the preoperative blood indices were similar in all groups. The differences in bleeding patterns in the screw insertion and correction stages were attributed to the poor bone quality of groups 2 and 3. Group 3 had the lowest bone quality, which caused loosening of the bone-screw interface during the correction stage and led to more bleeding. Patients with a T-score less than -2.5 showed a risk for high per-level EBL that was nine times higher than those with scores greater than -2.5 (p = 0.003).We investigated the blood loss patterns during different stages of scoliosis surgery. Patients with poor BMD showed a risk of blood loss nine times higher than those with good BMD.Underlying disorders play major roles in determining blood loss during surgical procedures. In particular, patients with neuromuscular diseases are thought to be at risk for increased blood loss during scoliosis surgery, but most reports addressing this q
A Comparative Study of Concretes Containing Crushed Limestone Sand and Natural Sand  [PDF]
Yeol Choi, Jae-Hyuk Choi
Open Journal of Civil Engineering (OJCE) , 2013, DOI: 10.4236/ojce.2013.31003
Abstract:

This paper describes the effects of high temperatures on the strength characteristic of crushed limestone sand concrete (CLSC). To compare, natural (river) sand concrete (NSC) and CLSC specimens were exposed to the three different high temperatures. Visual color-change and weight loss were also carefully examined through the tests. The test results indicated that the decreasing rate of compressive strength of CLSC after exposure to high temperature is slightly lower than that of NSC while the splitting tensile strength of CLSC indicated a very similar rate compared to NSC. Therefore, the strength variations of crushed limestone sand concrete after exposal to high temperature can be similarly treated as that of the natural sand concrete. Also it can be seen that the CLSC can use 0.5 power law equation to represent the relationship between compressive and splitting tensile strength before and after exposal to high temperature.

Bacterial Heavy Metal Resistance Genes and Bioremediation Potential  [PDF]
Hannah Johnson, Hyuk Cho, Madhusudan Choudhary
Computational Molecular Bioscience (CMB) , 2019, DOI: 10.4236/cmb.2019.91001
Abstract: There is a worldwide distribution of heavy metal pollution that can be managed with a bioremediation approach using microorganisms. Several bacterial species belonging to the Proteobacteria have been shown to tolerate heavy metal stress, including toxic salts of noblemetals. Rhodobacter sphaeroides, a model bacterium has previously been utilized for bioremediation studies. A bioinformatics approach was employed here to identify the distribution of genes associated with heavy metal tolerance among the sequenced bacterial genomes currently available on the NCBI database. The distribution of these genes among different groups of bacteria and the Cluster of Orthologous Groups (COGs) were further characterized. A total of 170,000 heavy metal related genes were identified across all bacterial species, with a majority of the genes found in Proteobacteria (46%) and Terrabacteria (39%). Analysis of COGs revealed that the majority of heavy metal related genes belong to metabolism (COG 3), including ionic transport, amino acid biosynthesis, and energy production.
Potential association between coronary artery disease and the inflammatory biomarker YKL-40 in asymptomatic patients with type 2 diabetes mellitus
Hyun Kim, Byung-Wan Lee, Young-Mi Song, Won Kim, Hyuk-Jae Chang, Dong-Hoon Choi, Hee Yu, EunSeok Kang, Bong Cha, Hyun Lee
Cardiovascular Diabetology , 2012, DOI: 10.1186/1475-2840-11-84
Abstract: We enrolled a total of 70 asymptomatic type 2 diabetic patients without a documented history of cardiovascular disease, and determined serum levels of chemerin, omentin-1, YKL-40, and sCD26. We performed coronary computed tomographic angiography (cCTA) in all subjects, and defined coronary artery stenosis?≥?50?% as significant CAD in this study.Subjects were classified into two groups: patients with suspected coronary artery stenosis on cCTA (group I, n?=?41) and patients without any evidence of stenosis on cCTA (group II, n?=?29). Group I showed significantly higher YLK-40 levels and lower HDL-C levels than group II (p?=?0.038, 0.036, respectively). Levels of chemerin, omentin-1, and sCD26 were not significantly different between the two groups. Serum YKL-40 levels were positively correlated with systolic/diastolic BP, fasting/postprandial triglyceride levels, and Framingham risk score. Furthermore, YKL-40 levels showed moderate correlation with the degree of coronary artery stenosis and the coronary artery calcium score determined from cCTA. In multivariate logistic analysis, after adjusting for age, gender, smoking history, hypertension, and LDL-cholesterol, YLK-40 levels showed only borderline significance.YKL-40, which is secreted primarily from inflammatory cells, was associated with several CVD risk factors and was elevated in type 2 diabetic patients with suspected coronary artery stensosis on cCTA. These results suggest the possibility that the inflammatory biomarker YKL-40 might be associated with coronary artery disease in asymptomatic patients with type 2 diabetes mellitus.Prediction and early diagnosis of coronary heart disease (CHD) facilitates appropriate intervention in the early stages of this disease. Despite our growing understanding of the pathophysiology of CHD in subjects with type 2 diabetes mellitus (T2D), predicting future CHD events remains largely reliant upon evaluation of traditional risk factors [1,2]. Even in apparently low- and interm
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