• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.47-51
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• 2012

In this study, the deformation behavior stability of sealing rings with three different cross sectional areas has been presented using a FEM technique. To investigate the deformation behavior stability, the initial compression rate of 25% has been applied to the sealing ring, which is molded with a nitrile butadiene rubber. The maximum strain, maximum stress, and maximum contact normal stress have been analyzed for the working fluid pressure of $25kgf/cm^2$. The FEM results show that the maximum strain of a hollow o-ring and a hollow rectangular ring with a hollow space in the center of a sealing ring is higher than that of a conventional o-ring, but the maximum stress and the maximum contact normal stress are low. In these results, the sealing rings with a hollow space in the center of the cross sectional area is recommended to increase an extended endurance stability of sealing rings. But, the solid sealing ring is designed to guarantee the sealing safety of a contact sealing ring.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.179-184
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• 2009

Magnetic Resonance Electrical Impedance Tomography (MREIT) is a new bio-imaging modality providing cross-sectional conductivity images from measurements of internal magnetic flux densities produced by externally injected currents. Recent MREIT studies demonstrated successful conductivity image reconstructions of postmortem and in vivo canine brain. However, the whole head imaging was not achieved due to technical issues related with electrodes and noise in measured magnetic flux density data. In this study, we used a new carbon-hydrogel electrode with a large contact area and injected 30 mA imaging current through a canine head. Using a 3T MREIT system, we performed a postmortem canine experiment and produced high-resolution conductivity images of the entire canine head. Collecting magnetic flux density data inside the head subject to multiple injection currents, we reconstructed cross-sectional conductivity images using the harmonic $B_z$ algorithm. The conductivity images of the canine head show a good contrast not only inside the brain region including white and gray matter but also outside the brain region including the skull, temporalis muscle, mandible, lingualis proprius muscle, and masseter muscle.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.655-660
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• 2016

Smoking is accountable for the fatality of a substantial number of persons and increases the likelihood of cancer and cardiovascular diseases. Although data have shown high prevalence rates of cigarette smoking in Saudi Arabia, relatively little is known about the broader scope. The objectives of this study were to investigate socio-demographic factors, patterns of use and cessation behavior associated with smoking in Saudi Arabia (KSA). The study utilized a cross-sectional, multi-step design of sampling. Residents (N=1,497; aged 15 years and older) were recruited from seven administrative areas in Southwest Saudi Arabia. A pretested questionnaire was utilized to obtain data on participant cigarette smoking, including their daily use, age, education, income, marital status and employment status. The current study is the first of its kind to gather data cessation behavior of Saudi subjects. With the exception of 1.5% females, all the respondents were male. The majority of the respondents were married, had a university level of education, were employed, and were younger than 34 years old. The same trends were also observed among smokers' samples. The current prevalence of cigarette smoking was 49.2% and 65.7% of smokers had smoking at less than 18 years of age. The mean daily use amongst smokers was 7.98 cigarettes (SD=4.587). More than 50% of the study sample had tried at least once to quit smoking. However, 42% of the smokers participating had never. On the other hand, about 25% of the respondents were willing to consider quitting smoking in the future. Modeling of cigarette smoking suggested that the most significant independent predictors of smoking behavior were geographic area, gender, marital status, education, job and age. Considerable variation in smoking prevalence was noted related with participant sociodemographics. Findings recommend the necessity for control and intervention programs in Saudi community.

• The Korean Journal of Pain
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• v.30 no.1
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• pp.51-58
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• 2017

Background: Recently symptoms-based screening questionnaires have gained attention for screening for a neuropathic pain component (NePC) in various chronic pain conditions. The present study assessed the usefulness of four commonly used NePC screening questionnaires including the Self-completed douleur neuropathique 4 (S-DN4), the ID Pain, the painDETECT questionnaire (PDQ), and the Self-completed Leeds Assessment of neuropathic Symptoms and Signs (S-LANSS) questionnaire in patients with chronic low back pain (CLBP) to assess the presence of NePC. Methods: This is a single-center cross-sectional study where patients with CLBP, with or without leg pain, were included. Participants were initially screened for NePC presence by a physician according to the regular practice, and later assessed using screening questionnaires. The diagnostic accuracy of these questionnaires was compared assuming the physician-made diagnosis as the gold standard. Results: A total of 215 patients with CLBP of which 164 (76.3%, 95% CI, 70.2-81.5) had a NePC were included. S-DN4, ID Pain, and PDQ have an area under the curve (AUC) > 0.8 indicating excellent discrimination. However, S-LANSS has an AUC of 0.69 (0.62-0.75), indicating low discrimination. S-DN4 has a significantly higher AUC as compared to ID Pain (d(AUC) = 0.063, P < 0.01) and S-LANSS (d(AUC) = 0.197, P < 0.01). But the AUC of S-DN4 does not significantly differ from that of PDQ (d(AUC) = 0.013, P = 0.62). Conclusions: S-DN4, ID Pain, and PDQ, but not S-LANSS, have good discriminant validity to screen for NePCs in patients with CLBP. Despite using all the tests, 20-30% of patients with an NePC were missed. Thus, these questionnaires can only be used as an initial clue in screening for NePCs, but do not replace clinical judgment.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.533-542
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• 2015

Little human tissue data are available for slow waves and migrating motor complexes, which are the main components of small bowel motility. We investigated the electrophysiological and mechanical characteristics of human ileal motility, in vitro. Ileum was obtained from patients undergoing bowel resection. Electrophysiological microelectrode recordings for membrane potential changes and mechanical tension recordings for contraction from smooth muscle strips and ileal segments were performed. Drugs affecting the enteric nervous system were applied to measure the changes in activity. Slow waves were detected with a frequency of 9~10/min. There were no cross-sectional differences in resting membrane potential (RMP), amplitude or frequency between outer and inner circular muscle (CM), suggesting that electrical activities could be effectively transmitted from outer to inner CM. The presence of the interstitial cell of Cajal (ICC) at the linia septa was verified by immunohistochemistry. Contractions of strips and segments occurred at a frequency of 3~4/min and 1~2/min, respectively. The frequency, amplitude and area under the curve were similar between CM and LM. In segments, contractions of CM were associated with LM, but propagation varied with antegrade and retrograde directions. Atropine, $N^W$-oxide-L-arginine, and sodium nitroprusside exhibited different effects on RMP and contractions. There were no cross-sectional differences with regard to the characteristics of slow waves in CM. The frequency of contractions in smooth muscle strips and ileal segments was lower than slow waves. The directions of propagation were diverse, indicating both mixing and transport functions of the ileum.

• Korean Journal of Veterinary Research
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• v.6 no.1
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• pp.82-91
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• 1966

Studies On the myelinated fibers of the recurrent laryneal nerves were made in five, species of domestic animals namely dog, pig, goat, horse and Korean ox. Throughout the studies, the following characteristics of the myelinated fibers were obtained. 1. The number, size and cross sectional area of the myelinated fibers seemed to be proportionally related to the animal body weights. 2. The highest peak of diameter size frequency distribution of the myelinated fibers, observed at the right cranial level, in dog, goat and horse were 4-6 micron group, while in the case of Korean ox, 10-12 micron group was the highest. 3. The highest peak of diameter size frequency distribution of the myelinated fibers, observed at the right caudal level of Korean ox was 6-8 micron group, and 4-6 micron group was the highest in the other animals. 4. The highest peak of diameter size frequency distribution of the myelinated fibers obsered at the left cranial level was same to that of right cranial level. 5. The highest peak of diameter size frequency distribution of the myelinated fibers, observed at the left caudal levels in dog, goat, horse and Korean ox was 4-6 micron group, while in case of pig, $14-16{\mu}$ group was the highest. 6. The largest cross sectional areas were found in the group of 10-16 micron in all species of animals. 7. The fiber diameter size frequency distribution of recurrent laryngeal nerves of dog, goat, pig and horse were bimodal and Korean ox seemed to be a unimodal.

• Journal of Integrative Natural Science
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• v.11 no.3
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• pp.139-147
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• 2018

Hippocampal atrophy is a well-established imaging biomarker of Alzheimer disease (AD). However, hippocampus is a non-homogenous structure with cytoarchitecturally and functionally distinct sub-regions or subfield, with each region performing distinct functions. Certain regions of the subfield have shown selective vulnerability to AD. Here, we are interested in studying the effects of normal aging and mild cognitive impairment on these sub-regional volumes. With a reliable automated segmentation technique, we segmented these subregions of the hippocampus in 101 cognitively normal (CN), 135 early mild cognitive impairment (EMCI), 67 late mild cognitive impairment (LMCI) and 48 AD subjects. Thereby, dividing the hippocampus into hippocampal tail (tail), subiculum (SUB), cornu ammonis 1 (CA1), hippocampal fissure (fissure), presubiculum (PSUB), parasubiculum (ParaSUB), molecular layer (ML), granule cells/molecular layer/dentate gyrus (GCMLDG), cornu ammonis 3(CA3), cornu ammonis 4(CA4), fimbria and hippocampal-amygdala transition area (HATA). In this cross sectional study of 351 ADNI subjects, no differences in terms of age, gender, and years of education were observed among the groups. Though, the groups had statistically significant differences (p < 0.05 after the multiple comparison correction) in the Mini-Mental State Examination (MMSE) scores. There was asymmetrical volume loss in the early stages of AD with the left hemisphere showing volume loss in regions that were unaffected in the right hemisphere. Bilateral parasubiculum, right cornu ammonis 1, 3 and 4, right fimbria and right HATA regions did not show any volume loss till the late MCI stages. Our findings suggest that the hippocampal subfield regions are selectively vulnerable to AD and also that these vulnerabilities are asymmetrical especially during the early stages of AD.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.20 no.3
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• pp.204-211
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• 2007

Objectives : Allergic rhinitis is one of the most common allergic diseases. The aim of this study was to evaluate the clincal effect of herbal medicine(Gamitonggue-tang) in patients with allergic rhinitis by using acoustic rhinometry. Methods : A total of 22 individuals with allergic rhinitis who visited the Dept. of Oriental Medical Opthalmology & Otolaryngology & Dermatology of Daegu Hanny Oriental Medical Center from June 1st, 2006 to February 28th, 2007 were included in this study. In this study, they were only treated with Gamitonggue-tang. For 4 weaks the flow resistance of nasal cavity and total nasal volume, nasal minimum cross-sectional area were measured by acoustic rhinometry at the 1st, the 14th and the 28th day. And symptom score of nasal obstruction were recorded. Results : There were no significant differences on sex, age and onset. After treatment(2, 4 weeks) the calculated flow resistance of nasal cavity, total nasal volume and nasal minimum cross-sectional showed no significant changes(p>0.05). But symptom score of nasal obstruction showed significant changes(p<0.05). Conclusions : Considering the above results, treatment with herbal medine(Gamitonggue-tang) could be efficacious in allergic rhinitis. Further studies in other methods are needed.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1515-1518
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• 2015

Background: Leukoplakia is an asymptomatic and potentially malignant change in the oral mucosa and high frequencies have been reported among smokers. The present study concerned the prevalence of tobacco use and leukoplakia and also associations between the two. Study design: This cross sectional survey was conducted amongst the Gond tribal population of Kundam Block, Jabalpur district, Madhya Pradesh state, Central India during 2007 to 2009. Screening for leukoplakia was conducted by a medical officer with two mouth mirrors. It is only based on visual inspection and oral pathology was not performed. A semi-structured questionnaire was used to collect information on socio-demographic and smoking habits. Prevalence of leukoplakia among users and non-users of tobacco was calculated in terms of percentages. Results: Of 1,552 individuals aged more than 12 years of age who were screened, 144 (9.3%) were found to have oral leukoplakia. The prevalence of leukoplakia was significantly elevated among tobacco users as compared to non-users (11% vs 2.5%; p<0.001). The percentage of leukoplakia was almost similar in both tobacco smokers and chewers (9% vs 11%; p=0.304). However, the percentage of leukoplakia was especially high among those chewers who also smoked tobacco (21.9%). Conclusions: The findings of the present study showed a positive effect of tobacco use and prevalence of leukoplakia. Also the prevalence was very high among Gond tribe, a marginalized population living in central India. There is a need for effective screening and treatment of leukoplakia in this area.