• Title/Summary/Keyword: cross-over studies

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Time dependent numerical simulation of MFL coil sensor for metal damage detection

  • Azad, Ali;Lee, Jong-Jae;Kim, Namgyu
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.727-735
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    • 2021
  • Recently, non-destructive health monitoring methods such as magnetic flux leakage (MFL) method, have become popular due to their advantages over destructive methods. Currently, numerical study on this field has been limited to simplified studies by only obtaining MFL instead of induced voltage inside coil sensor. In this study, it was proposed to perform a novel numerical simulation of MFL's coil sensor by considering vital parameters including specimen's motion with constant velocity and saturation status of specimen in time domain. A steel-rod specimen with two stepwise cross-sectional changes (i.e., 21% and 16%) was fabricated using low carbon steel. In order to evaluate the results of numerical simulation, an experimental test was also conducted using a magnetic probe, with same size specimen and test parameters, exclusively. According to comparative results of numerical simulation and experimental test, similar signal amplitude and signal pattern were observed. Thus, proposed numerical simulation method can be used as a reliable source to check efficiency of sensor probe when different size specimens with different defects should be inspected.

An Empirical Study of the Effect of Oil Prices on International Price Dispersion (원유가격이 국가 간 가격분산에 미치는 영향에 대한 실증 연구)

  • Lee, Inkoo
    • Korea Trade Review
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    • v.43 no.2
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    • pp.69-86
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    • 2018
  • The paper studies the degree of international price dispersion for 300 individual goods and services between cities of three country groups over 1999 and 2013, focusing on the role of oil prices in generating deviations from the law of one price. We find that while oil prices did not contribute to the trend in cross-country price dispersion, it does account for within-country price dispersion. Once the oil price effect is subtracted out, the remaining price dispersion between U.S. cities no longer exhibits a noticeable upward trend. If oil prices increase transportation costs, they should increase the deviations from the law of one price, raising price dispersion. Our findings indicate that this effect is more pronounced within a country, while factors such as elasticity of substitution and other trade barriers are likely to matter more in price dispersion across borders. We view our results as complementary to those that emphasize the role of time-varying factors in accounting for price dispersion.

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The Effect of Elastic Tape on Lower Extremity Muscle Activity in Squats of Young Female Adults: A Cross-sectional Pilot Study

  • Namjeong Cho;Yangrae Kim
    • Physical Therapy Korea
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    • v.30 no.3
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    • pp.169-173
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    • 2023
  • Background: In terms of physical performance, elastic tape (ET) is known to contribute to injury prevention and performance enhancement. Objects: This study aimed to compare and analyze the effect on lower extremity muscle activity of young adult women with and without ET during squats. Methods: In this study, six healthy, young women were recruited as participants in a university laboratory. Participants were allocated to two groups of three after measuring muscle activity in a pre-test, and the experiment was conducted for a total of two weeks (two sessions). First, 10 half squats were taped once in the first week, and 10 half squats were performed without taping in the second week. The other group did this in reverse and measured muscle activity after the squat was over. Results: As a result of this study, there was no significant difference in the quadriceps with or without ET (Z = -0.11, p > 0.05). Similarly, no significant difference was found in hamstring (Z = -0.31, p > 0.05). Conclusion: No beneficial effect was found on changes in muscle activity following ET application during squats. Further studies require randomized controlled trials that increase the number of participants and the intensity of the intervention, and measure pain, function, and performance rather than muscle properties depending on the biomechanical lifting mechanism.

Online Tie Formation in Enterprise Social Media

  • Yongsuk Kim;Gerald C. (Jerry) Kane
    • Asia pacific journal of information systems
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    • v.29 no.3
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    • pp.382-406
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    • 2019
  • We study the antecedents to tie formation on an (Facebook-like) enterprise social media platform implemented to support cross-boundary connections. Research has produced mixed findings regarding the role of social media in cultivating bridging vs. closed networks. We examine the tie formation patterns of 1,386 enterprise social media users over a two-year period. Specifically, we observe who became (or chose not s become) "friends" with whom at the dyadic level and relate the decisions to various mechanisms that affect one's network to expand, constrain, or bridge. Using logistic and OLS regressions, we find that users tend to form ties via reciprocity and transitivity (with friends of friends), both of which help expand one's network. We also find strong networking tendency toward functional and hierarchical homophily (same business unit and same rank, respectively), which is likely to constrain one's network (closed network structure). We find that one's participation in various online interest groups is likely to open one's network (bridging network structure) while no evidence found for preferential attachment. Overall, we find that enterprise social media offers features, some of which are likely to foster bridging while others foster closed networks via different mechanisms.

Release and Characterization of Multiple Coated Pellets Containing Melatonin (멜라토닌이 함유된 다층 코팅 펠렛의 방출 및 특성분석)

  • Kang, Bok-Ki;Khang, Gil-Son;Kim, Jong-Min;Jeung, Sang-Young;Lee, Hai-Bang;Cho, Sun-Hang
    • Journal of Pharmaceutical Investigation
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    • v.33 no.3
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    • pp.179-185
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    • 2003
  • Melatonin (MT) is an indole amide pineal hormone. It has not only very short half-life but also pH-sensitive property. The sustained release dosage form which delivers MT in a circadian fashion over 8 h is clinical value. The purpose of this study is to prepare sugar beads using multiple coating methods and enteric-coated in a sustained release to evaluate in vitro release characteristics in simulated gastric and intestinal fluids. The $Eudragit^{\circledR}$ as a polymer, sustained release membrane, and triethylcitrate (TEC) as a plasticzer were used. Multi-coated melatonin delivery system was composed of sugar, various excipients, $Eudragit^{\circledR}$ and enteric materials (e.g. hydroxy propyl methyl cellulose phthalate, HPMCP), and prepared by fluid bed coater. The dissolution test was carried out using the basket method at a stirring speed of 100 rpm at $37^{\circ}C$ in simulated gastric (pH 1.2) and intestinal fluid (pH 7.4). The released amount of MT was determined by High performance liquid chromatography method. The morhologies of surface and cross section of multi-coated beads were observed by scanning electron microscope. Size of multi-coated sugar beads was ranged over $1000{\sim}1300\;{\mu}m$. The release rate of MT from coated beads was limited in simulated gastric fluid (pH 1.2), but it was sustained in intestinal fluid (pH 7.4) during $3{\sim}8$ hours. The MT beads may provide small-intestine-targeted device for oral delivery. Studies on animal and relative experiment are in process.

The Estimation of Prevalence of Diabetes Mellitus in a Rural Adult Population (일부 농촌 성인의 당뇨병 유병률 추정)

  • Park, Sue-Kyung;Kim, Joung-Soon
    • Journal of Preventive Medicine and Public Health
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    • v.29 no.3 s.54
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    • pp.483-494
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    • 1996
  • The objectives of this study are to estimate the prevalence of diabetes mellitus (DM) and to identify risk factors associated with fasting blood sugar in a rural adult population. We carried out a cross - sectional study on the residents over 30-year old. Among the 1077 eligible subjects, 725 persons responded to the study;the study consisted of interview on family and past history of DM, anthropometry, blood pressure, and blood sugar level in each subjects. Only 707 subjects of 725 participants had fasting blood sugar(FBS) examined and the rest, 18 subjects were had casual blood sugar examined due to failure of fasting over 8 - hour. When subjects had $FBS\geq140mg/dl$, 2 hours postprandial blood sugar level was checked after 75g oral glucose loading. The prevalence of DM was 8.9%, and age standarized prevalence rate adjusted to Korean population of 1995 was 5.8%. Mean and SD of fasting blood sugar in men was $99.8{\pm}22.6$, and in women was $111.5{\pm}29.9$. Mean levels of fasting blood sugar were significantly higher in women than in man and as their ages advanced the prevalences increased in both sexes. PP2 blood sugar levels were significantly higher in elder age and in persons with higher FBS levels than others. The risk factors associated with FBS were past history of diabetes, sex, socioeconomic status and waist - to - hip circumference ratio;the risk of diabetes was increased in female, people with past DM history, central obesity and low socioeconomic state. The low socioeconomic status associated with DM in this study, which is different from other study results, should be pursued in further studies.

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COMPARATIVE HISTOMORPHOMETRIC ANALYSIS OF MANDIBLE AND ILIAC BONE ON BONE DENSITY (하악골과 장골의 조직형태계측 비교)

  • Yoo, So-Jeong;Chung, Moon-Kyu
    • The Journal of Korean Academy of Prosthodontics
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    • v.38 no.1
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    • pp.12-25
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    • 2000
  • To demonstrate possible influences of general bone density on the mandible, histomorphometric analysis was carried out in mandibles and iliac bones and the correlation of the two bone densities was tested. Comparison of bony density in women and men over 60 years in the mandible was carried out too. Quantitative computed tomography(QCT) was taken in cross-section of mandibles at the same site where histomorphometric analysis was peformed to evaluate the reliability of QCT. The analysis included 40 cadavers with no known diseases affecting the bones. The subjects consisted of 15 females and 25 males with a mean age of 60.3 years. Spearman correlation analysis and Wilcoxon rank sum test was performed. The results were as follows. 1. There was statistically no correlation between the mandible and iliac bone in the values of corrected cortical width(CCW), cortical porosity(POR) in cortex, and total bone volume(TBV), mean trabecular plate thickness(MTPT), mean trabecular plate density(MTPD), and mean trabecular plate separation(MTPS) in trabecular bone. 2. Comparison of women and men over 60 years, men had statistically higher bone density than women except fir POR of buccal and lingual cortex, and WTPD of alveolar trabeculae in mandible. 3. There was statistically significant correlation between TBV of trabecular bone and CT No., but not between POR and CT No. in mandible. According to the results above, there was no correlation between mandible and iliac bone density and between mandibular bony density and age. Further studies are required to support the results. A more noninvasive method to be able to measure the bone density of mandible should be developed and it is necessary to accumulate data on the normal values of bone density of mandible according to age and sex. Further study should be carried out about QCT to measure mandibular bony density using QCT.

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Comparison Study of Uptake of Colorectal Cancer Testing between Ethnic Minorities and the General Population in Hong Kong

  • Choi, Kai-Chow;So, Winnie Kwok-Wei;Chen, Joanne Man-Ting;Lau, Grace Chieh;Lee, Paul Chi-Wai;Chan, Carmen Wing-Han
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7713-7720
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    • 2015
  • Background: Colorectal cancer (CRC) is one of the most common cancers. This study aimed to compare the uptake of CRC testing in the general public and in ethnic minorities in Hong Kong. Materials and Methods: This cross-sectional survey covered 2,327 South Asian and Chinese adults aged over 50, recruited from two separate studies. A structured questionnaires were administered by research staff over the telephone or in faceto-face interviews. Results: The uptake rate of CRC testing among South Asians was significantly lower than that of the general population in Hong Kong. Factors associated with the uptake rate were health professional's recommendation, perception of regular visits to doctor, use of complementary therapy, ethnicity, perceived susceptibility to cancer, presence of chronic illness, and education level. In addition, a significant interaction (p<0.05) between ethnicity and health professionals' recommendations was found, after adjustment for the main independent factors identified. Conclusions: Older people with lower educational attainment, without chronic illness and those have lower perceived susceptibility to cancer may be targeted for CRC testing promotion in the society. In addition, health professionals can play a highly influential role in promoting such testing, particularly among ethnic minorities.

Age Specific Cytological Abnormalities in Women Screened for Cervical Cancer in the Emirate of Abu Dhabi

  • Al Zaabi, Muna;Al Muqbali, Shaikha;Al Sayadi, Thekra;Al Ameeri, Suhaila;Coetsee, Karin;Balayah, Zuhur;Ortashi, Osman
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.15
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    • pp.6375-6379
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    • 2015
  • Background: Cervical cancer is the second most common cancer in women worldwide, with about 500,000 new cases and 270,000 deaths each year. Globally, it is estimated that over one million women currently have cervical cancer, most of whom have not been diagnosed, or have no access to treatment that could cure them or prolong their lives. In the United Arab Emirates (UAE) cervical cancer is the third most common cancer in women. Materials and Methods: A population-based cross-sectional retrospective survey of cervical smear abnormalities was conducted in the Emirate of Abu Dhabi, UAE, from January 2013 to December 2013 by collecting consecutive liquid-based cytology samples from the Department of Pathology at the SKMC Hospital in Abu Dhabi city. Results: The total number of women screened for cervical cancer for the year 2013 at SKMC was 4,593, with 225 (4.89%) abnormal smears. The majority of the abnormal smear results were atypical squamous cells of undetermined significance (ASCUS) 114 (2.48%). This study showed 60% increase in the rate of abnormal cervical smears in the UAE over the last 10 years. In this study the highest incidence of high grade abnormalities were seen in women above the age of 61years (1.73%), this might be due to the fact that this group of women missed the chance of screening of cervical cancer earlier in their lives or could be explained by the well-known second peak of HPV infection seen in many prevalence studies. Conclusions: We conclude that the rate of abnormal cervical smear in the screened Abu Dhabi women is not different from the rate in developed countries. A notable increase in both low and high grade abnormalities has occurred within the last decade.

Transnational Labor Migration in Southeast Asia and Regional Governance: In Search of Good Governance (동남아시아의 이주노동과 지역 거버넌스)

  • Choi, Horim
    • The Southeast Asian review
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    • v.20 no.2
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    • pp.135-178
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    • 2010
  • This study is to seek alternatives for regional governance related to transnational labor migration issues in Southeast Asia. This study examined the present situation and trends of labor migration in the region, reviewed involved transnational issues, and identified the current issues of governance to seek alternatives for regional governance. The increase in cross-border labor migration is no doubt a sign of growth and dynamism of the region and greater integration of their economies. But it also poses complex policy and management issues as well as transnational issues over such as unequal economic profits, illegal migration, human rights, and social security issues. In this reality, regional governance is a very important theme and the efforts to manage their migration inherently involve fundamental conflict and tension between related countries and regions. However, politics and governance of transnational migrant workers in Southeast Asia are still pursued at the national level. To resolve these issues, it is urgently required to secure not only collaboration between the parties concerned but also governance at the regional level. Findings of this study are: First, although labor migration has been a relatively long-time transnational issue, the history of addressing the issue at the regional governance is very short and still inceptive. Second, given its size, labor migration in Southeast Asia requires effective regional governance but no breakthrough was possible due to the conflict of interests between origin and destination countries and the conflict of logic between the labor market and the state. Third, the issue of labor migration is an important element for the formation of economic and socio-cultural communities the ASEAN countries have pursued. Fourth, it is urgently needed to seek alternatives for good and effective regional governance as a key to resolving these issues over migrant workers in Southeast Asia.