• International Journal of Oral Biology
• /
• v.37 no.4
• /
• pp.181-188
• /
• 2012

As the demand for large-scale analysis of gene expression using DNA arrays increases, the importance of the surface characterization of DNA arrays has emerged. We compared the efficiency of molecular biological applications on solid-phases with different surface polarities to identify the most optimal conditions. We employed thiol-gold reactions for DNA immobilization on solid surfaces. The surface polarity was controlled by creating a self-assembled monolayer (SAM) of mercaptohexanol or hepthanethiol, which create hydrophilic or hydrophobic surface properties, respectively. A hydrophilic environment was found to be much more favorable to solid-phase molecular biological manipulations. A SAM of mercaptoethanol had the highest affinity to DNA molecules in our experimetns and it showed greater efficiency in terms of DNA hybridization and polymerization. The optimal DNA concentration for immobilization was found to be 0.5 ${\mu}M$. The optimal reaction time for both thiolated DNA and matrix molecules was 10 min and for the polymerase reaction time was 150 min. Under these optimized conditions, molecular biology techniques including DNA hybridization, ligation, polymerization, PCR and multiplex PCR were shown to be feasible in solid-state conditions. We demonstrated from our present analysis the importance of surface polarity in solid-phase molecular biological applications. A hydrophilic SAM generated a far more favorable environment than hydrophobic SAM for solid-state molecular techniques. Our findings suggest that the conditions and methods identified here could be used for DNA-DNA hybridization applications such as DNA chips and for the further development of solid-phase genetic engineering applications that involve DNA-enzyme interactions.

• KSBB Journal
• /
• v.14 no.6
• /
• pp.661-664
• /
• 1999

Proteins were extracted from an aqueous phase with reversed micelles. The effect of pH, and salt concentration on the solubilization of lysozyme in AOT/isooctane solution was studied to explore the potential for employing this solvent system in the large-scale recovery and concentration of proteins using liquid extraction. For pH values below the isoelectric point, pl of the protein, solubilization was high, probably owing to strong electrostatic interactions between the positively charged proteins and the anionic surfactant heads forming the inner micelle wall. At low ionic strength complete solubilization of the protein was observed. A pH higher than the pl of lysozyme and a salt concentration lower than that of the water pool were required for the recovery aqueous phase to ensure the back extraction of lysozyme from the AOT reversed micelles.

• Geomechanics and Engineering
• /
• v.15 no.3
• /
• pp.869-877
• /
• 2018

The continually growing demand for underground space in dense urban cities is also driving the demand for underground highways. Building the underground highway tunnel, however, can involve complex design and construction considerations, particularly when there exists divergence or convergence in the tunnel. In this study, interaction between two asymmetric noncircular tunnels-that is, a larger main tunnel and a smaller tunnel diverging from the main tunnel, was investigated by examining the distributions of the principal stresses and the strength/stress ratio for varying geometric conditions between the two tunnels depending on diverging conditions using both numerical analysis and scale model test. The results of numerical analysis indicated that for the $0^{\circ}$, $30^{\circ}$, $60^{\circ}$ diverging directions, the major principal stress showed an initial gradual decrease and then a little steeper increase with the increased distance from the left main tunnel, except for $90^{\circ}$ where a continuous drop occurred, whereas the minor principal stress exhibited an opposite trend with the major principal stresses. The strength/stress ratio showed generally a bell-shaped but little skewed to left distribution over the distance increased from the left larger tunnel, similarly to the variation of the minor principal stress. For the inter-tunnel distance less than 0.5D, the lowest strength/stress ratio values were shown to be below 1.0 for all diverging directions ($0^{\circ}$, $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$). The failure patterns observed from the model test were found to be reasonably consistent with the results of numerical analysis.

• Journal of the Korea Society for Simulation
• /
• v.23 no.4
• /
• pp.181-188
• /
• 2014

Heterogeneous physical systems and computational devices are incorporated on a large-scale in a CPS (cyber-physical system) environment. Simulations can be useful for the reliable behaviors of CPSs. Time synchronization is one of major technical issues for the simulations. In the CPS, distributed systems control themselves by interacting with each other during runtime. When some simulation models have high complexity, wrong control commands as well as incorrect data can be exchanged due to the time error. We propose a time synchronization algorithm for the hybrid model that has characteristics of both continuous time systems and discrete event systems. In addition, we develop a CPS simulator based on our algorithm. For the verification of the algorithm and the execution of the simulator, we develop an example hybrid model and simulate considering user controls as well as interactions among the distributed systems.

• Archives of Plastic Surgery
• /
• v.44 no.5
• /
• pp.428-433
• /
• 2017

Background Candidate characteristics for hand surgery fellowship training remains unknown, as very little data is available in the literature. This study aims to provide information on the criteria that are employed to select candidates for the hand surgery fellowship match. Methods A 38-question survey was sent in April 2015 to all Accreditation Council for Graduate Medical Education recognized hand surgery fellowship program directors (n=81) involved in the U.S. match. The survey investigated factors used for the selection of applicants, including medical school, residency training, research experience, fellowship interview, and candidate characteristics. A 5-point Likert scale was used to grade 33 factors from "not at all important" (1) to "essential in making my decision" (5); or for five controversial factors from "very negative impact" (1) to "very positive impact in making my decision" (5). Results A total of 52% (42 out of 81) of responses were received from hand surgery fellowship program directors. The most important influential factors were interactions with faculty during interview and visit ($4.6{\pm}0.6$), interpersonal skills ($4.6{\pm}0.5$), overall interview performance in the selection process ($4.6{\pm}0.6$), professionalism and ethics ($4.6{\pm}0.7$), and letters of recommendation from hand surgeons ($4.5{\pm}0.7$). Factors that have a negative impact on the selection process include visa requirement ($2.1{\pm}1.2$), graduate of non-plastic surgery residency program ($2.4{\pm}1.3$), and graduate of a foreign medical school ($2.4{\pm}1.1$). Conclusions This study provides data on hand surgery fellowship directors' perception on the criteria important for fellowship applicant selection, and showed that interview-related criteria and letters of recommendation are the important factors.

• Journal of Science and Technology Studies
• /
• v.13 no.2
• /
• pp.1-35
• /
• 2013

The aim of this article is to criticize the discourses and practices of the appropriate technology for international development cooperation in Korea which focus narrowly on the technologies and are oriented to the providers of technologies. To present an alternative, we will discuss the appropriate technology by the insights from 'socio-technical system' studies which underline not only technological side but also the social, institutional and user's side, and analyze the interactions between them. This research deals with several cases mainly regarding small scale's renewable energy from Laos, Thailand, Bangladesh, Mongolia and Nepal. We put out some suggestions to improve the discourse and practices of appropriate technology in field of international cooperation by Korea.

• Journal of the Microelectronics and Packaging Society
• /
• v.14 no.3
• /
• pp.29-36
• /
• 2007

The main objectives of this study are to investigate the micro-scale energy transfer mechanism for silicon wafer and to find an efficient way for fabrication of silicon wafer through-hole by using the femtosecond pulse laser ablation. In addition, the electron-phonon interactions during laser irradiation are discussed and the carrier number density and temperatures are estimated. In particular, the present study observes the shapes of silicon wafer through-hole with $100\;{\mu}m$ diameter and it also measures the heat-affected area and the ablation depths fur different laser fluences by using the optic microscope and the three-dimensional profile measurement technique. First, from numerical investigation, it is found that the nonequilibrium state exists between electrons and phonons during laser irradiation. From experimental results, it should be noted that the heat-affected area increases with laser fluence, and the optimal conditions for through-hole formation with minimum heat affected zone are finally obtained.

• Structural Engineering and Mechanics
• /
• v.76 no.1
• /
• pp.141-151
• /
• 2020

This manuscript tends to investigate influences of nanoscale and surface energy on a static bending and free vibration of piezoelectric perforated nanobeam structural element, for the first time. Nonlocal differential elasticity theory of Eringen is manipulated to depict the long-range atoms interactions, by imposing length scale parameter. Surface energy dominated in nanoscale structure, is included in the proposed model by using Gurtin-Murdoch model. The coupling effect between nonlocal elasticity and surface energy is included in the proposed model. Constitutive and governing equations of nonlocal-surface perforated Euler-Bernoulli nanobeam are derived by Hamilton's principle. The distribution of electric potential for the piezoelectric nanobeam model is assumed to vary as a combination of a cosine and linear variation, which satisfies the Maxwell's equation. The proposed model is solved numerically by using the finite-element method (FEM). The present model is validated by comparing the obtained results with previously published works. The detailed parametric study is presented to examine effects of the number of holes, perforation size, nonlocal parameter, surface energy, boundary conditions, and external electric voltage on the electro-mechanical behaviors of piezoelectric perforated nanobeams. It is found that the effect of surface stresses becomes more significant as the thickness decreases in the range of nanometers. The effect of number of holes becomes significant in the region 0.2 ≤ α ≤ 0.8. The current model can be used in design of perforated nano-electro-mechanical systems (PNEMS).

• Journal of Oral Medicine and Pain
• /
• v.42 no.4
• /
• pp.116-124
• /
• 2017

Purpose: Burning mouth syndrome (BMS) is a disabling pain that mostly occurs in elderly women, but rarely in men. It is characterized by an unremitting oral burning sensation and pain without detectable oral mucosal changes. We investigated the clinical and hematologic features of middle-aged men with BMS, and compared the results to those of men with oral mucositis. Methods: Five men with BMS ($48.60{\pm}6.19years$) and five age-matched controls with oral mucositis ($49.80{\pm}15.26years$) underwent clinical and psychological evaluations and blood tests. Psychological status was evaluated using the Symptom Checklist-90-Revised. Cortisol, estradiol, progesterone, testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), and antidiuretic hormone (ADH) levels and erythrocyte sedimentation rate (ESR) were determined from the blood samples. Results: ADH level was significantly lower in men with BMS than in the controls. ADH levels correlated with testosterone (p<0.01), and ACTH levels strongly correlated with ESR (p<0.05). Progesterone level positively correlated with FSH and LH levels. Pain intensity on a visual analogue scale correlated with estradiol level only in men with BMS. Among psychological factors, the obsessive-compulsive disorder, interpersonal-sensitivity, and anxiety scores were higher in men with BMS than in the controls (p<0.05). However, no correlations were observed between the psychological and hematologic factors in both groups. The BMS symptoms presented only on the tongue, with the lateral border being the most prevalent area. Conclusions: Men with BMS may experience dysregulated endocrinologic or psychoneuroendocrinologic interactions, which might affect oral BMS symptoms, aggravating the severity of the burning sensation.

• Journal of Korea Water Resources Association
• /
• v.42 no.9
• /
• pp.691-702
• /
• 2009

This study makes a systematic approach to Hack's law considering self-affinity and self-similarity of natural basins as well as the elongation of corresponding catchment-plan forms. Catchment-plan forms extracted from DEM appear to be the population come from the interactions of 2 hypotheses on Hack's law. It is judged that the elongation measures based on inertia moments are more intuitive than the ones based on main channel lengths. The exponent of Hack's law, h, seems to be similar to the result of Gray's study (1961). However Hurst exponent, H, being 0.96 imply that catchment-plan forms considered in this study have isotropic increasing properties with scale. From this point of view it is inferred that the shapes of the basins in this study would be more affected from self-similarity of main channel lengths than self-affinity of catchment-plan forms.