• Journal of Biomedical Engineering Research
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• v.39 no.5
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• pp.220-228
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• 2018

The internal resistance of microbial fuel cell (MFC) using stainless steel skein for oxidizing electrode was investigated and the factors affecting the voltage generation were identified. We also investigated the effect of power management system (PMS) on the usability for MFC and the removal efficiency of organic pollutants. The performance of a stack microbial fuel cell connected with (PMS) or PMS+LED was analyzed by the voltage generation and organic matter reduction. The maximum power density of the unit cells was found to be $5.82W/m^3$ at $200{\Omega}$. The maximum current density was $47.53A/m^3$ without power overshoot even under $1{\Omega}$. The ohmic resistance ($R_s$) and the charge transfer resistance ($R_{ct}$) of the oxidation electrode using stainless steel skein electrode, were $0.56{\Omega}$ and $0.02{\Omega}$, respectively. However, the sum of internal resistance for reduction electrode using graphite felts loaded Pt/C catalyst was $6.64{\Omega}$. Also, in order to understand the internal resistance, the current interruption method was used by changing the external resistance as $50{\Omega}$, $300{\Omega}$, $5k{\Omega}$. It has been shown that the ohm resistance ($R_s$) decreased with the external resistance. In the case of a series-connected microbial fuel cell, the reversal phenomenon occurred even though two cells having the similar performance. However, the output of the PMS constantly remained for 20 hours even when voltage reversal occurred. Also the removal ability of organic pollutants (SCOD) was not reduced. As a result of this study, it was found that buffering effect for a certain period of time when the voltage reversal occurred during the operation of the microbial fuel cell did not have a serious effect on the energy loss or the operation of the microbial fuel cell.

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.42-47
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• 2008

Purpose: Advanced techniques now make it possible to remove considerable amounts of subcutaneous adipose tissue more safely with minimum blood loss. However, few have analyzed the metabolic consequences of liposuction. The purpose of this study was to identify the early effects of the surgical removal of subcutaneous fat on metabolic changes in patients who have undergone liposuction. Methods: Nineteen patients were evaluated from June 2005 to December 2005. Preoperative body weight, serums levels of lipids, apolipoprotein A1, dehydroepiandrosterone(DHEA), uric acid, insulin, and glucose were evaluated. Insulin resistance was determined using the homeostasis model assessment of insulin resistance (HOMA-IR), which is based on fasting glucose and insulin concentrations. All of these data were remeasured in 1 and 4 weeks postoperatively. Tumescent fluid was infiltrated using the superwet technique. The liposuction device used was a $Liposlim^{(R)}$ power-assisted unit. Results: Average volumes of infiltrate and aspirate were 3,268mL and 2,892mL, respectively. Results in 1 week postoperatively demonstrated a significant difference in high-density lipoprotein(HDL) cholesterol, apolipoprotein A1, insulin, and HOMA-IR levels. However, all values were within normal limits and returned to baseline in 4 weeks postoperatively.Conclusion: This study provides little to support the presumed therapeutic effect of liposuction. And, it is unclear whether liposuction can prevent or be used to treat the metabolic complications of obesity. However, the results of the present study lead us to believe that liposuction is a metabolically safe procedure.

• Structural Engineering and Mechanics
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• v.87 no.1
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• pp.47-56
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• 2023

Any pre-existed delamination defect present during manufacturing or induce during service loading conditions in the wingskin adherend invariably shows a greater loss of structural integrity of the spar wingskin joint (SWJ). In the present study, inter-laminar delamination propagation at the critical location of the SWJ has been carried out using contact and multi-point constraint finite elements available with commercial FE software (ANSYS APDL). Strain energy release rates (SERR) based on virtual crack closure technique have been computed for evaluation of the opening (Mode-I), sliding (Mode-II) and cross sliding (Mode-III) modes of delamination by sequential release of multi point constraint elements. The variations of different modes of SERR are observed to be significant by considering varied delamination lengths, material properties of adherends and radius of curvature of the SWJ panel. The SERR rates are seen to be much different at the two pre-embedded delamination ends. This shows dissimilar delamination propagation rates. The maximum is seen to occur in the delamination front in the unstiffened region of the wingskin. The curvature geometry and material anisotropy of SWJ adherends significantly influences the SERR values. Increase in the SERR values are observed with decrease in the radius of curvature of wingskin panel, keeping its width unchanged. SWJs made with flat FRP composite adherends have superior resistance to delamination damage propagation than curved composite laminated SWJ panels. SWJ made with Boron/Epoxy (B/E) material shows greater resistance to the delamination propagation.

• Corrosion Science and Technology
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• v.3 no.6
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• pp.227-232
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• 2004

The carboxylates as a corrosion inhibitor has been studied by many researchers because of its environmental safety and low depletion rate. However, conventional test methods of inhibitor such as weight loss measurements, linear polarization resistance and corrosion potential monitoring etc., evaluate uniform corrosion of metals. These methods are unable to evaluate crevice-related corrosions, which are encountered in most of heat exchanging facilities. In order to choose the optimum corrosion inhibitor, the appropriate test methods are required to evaluate their performances in service environment. From this point of view, polarization technique was used to evaluate the characteristics of sodium heptanoate on corrosion behavior for carbon steel. Especially a thin film crevice sensor technique were applied to simulate the crevice corrosion in this study. From these experiments, we found that oxygen as an oxidizing agent was required to obtain stable passive film on the metal. Presence of oxygen, however, accelerated crevice corrosion. Potential shift by oxygen depletion and weakened inhibitive film inside the crevice were responsible for such accelerated feature. It is shown that film for corrosion inhibition is a mixture of sodium heptanoate and iron (II) heptanoate as reaction product of iron surface and sodium heptanoate. The iron (II) heptanoate which has been synthesized by reaction of heptanoic acid and ferrous chloride in methanol solution forms bidentate complex.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.156-158
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• 1995

Total spinal anesthesia is a well documented serious life threatening complication which results from an attempted spinal or epidural analgesia. We had an accidental total spinal anesthesia associated with a cranial nerve paralysis and an eventual unconsciousness during epidural analgesia. A 45-year-old female with an uterine myoma was scheduled for a total abdominal hysterectomy under the epidural analgesia. A lumbar tapping for the epidural analgesia was performed in a sitting position at a level between $L_{3-4}$, using a 18 gauge Tuohy needle. Using the "Loss of Resistance" technique to identify the epidural space, the first attempt failed; however, the second attempt with the same level and the technique was successful. The epidural space was identified erroneously. However, fluid was dripping very slowly through the needle, which we thought was the fluid from the normal saline which was injected from the outside to identify the space. Then 20 ml of 2% lidocaine was administered into the epidural space. Shortly after the spinal injection of lidocaine, many signs of total spinal anesthesia could be clearly observed, accompanied by the following progressing signs of intracrainal nerve paralysis: phrenic nerve, vagus nerve, glossopharyngeal nerve and trigeminal nerve in that order. Then female was intubated and her respiration was controlled without delay. The scheduled operation was carried out uneventfully for 2 hours and 20 minutes. The patient recovered gradually in th4e reverse order four hours from that time.

• Korea-Australia Rheology Journal
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• v.13 no.2
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• pp.67-81
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• 2001

The development of new techniques for the dynamic measurement of linear viscoelastic properties is an active area of rheometry, and this paper surveys some novel deformation geometries which have been recently reported e.g. oscillating probe-type devices which are imbedded in or placed on the surface of the sample. Small amplitude band-limited pseudorandom noise is used for the displacement signal, with Fourier analysis of the complex waveform of the resistance force yielding the frequency dependent viscoelastic material functions (e.g. storage and loss moduli G", G"). Theoretical calculations of the fundamental equations relating force to displacement and instrument geometry, were carried out with the aid of the correspondence principle of linear viscoelasticity. The rapidity of the tests and flexibility in terms of sample preparation and stiffness mean that this basic technique should find many applications in rheometry. Three examples of oscillatory tests are presented in detail squeeze flow, imbedded needle and concentric sliding cylinder geometries.eometries.

• Development and Reproduction
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• v.27 no.1
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• pp.1-7
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• 2023

Small-cell lung cancer (SCLC) continues to be the deadliest of all lung cancer types. Its high mortality is largely attributed to the unchangeable development of resistance to standard chemo/radiotherapies, which have remained invariable for the past 30 years, underlining the need for new therapeutic approaches. Recent studies of SCLC genome revealed a large number of somatic alterations and identified remarkable heterogeneity of the frequent mutations except for the loss of both RB and P53 tumor suppressor genes (TSGs). Identifying the somatic alterations scattered throughout the SCLC genome will help to define the underlying mechanism of the disease and pave the way for the discovery of therapeutic vulnerabilities associated with genomic alterations. The new technique made it possible to determine the underlying mechanism for the discovery of therapeutic targets. To these ends, the techniques have been focused on understanding the molecular determinants of SCLC.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1858-1860
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• 1999

To fabricate superconducting multiplexers with narrow pass band characteristics and reduce the physical size of device, we have designed multiplexer using hair-pin type filters with the center frequency of 13.6 GHz. Multiplexers have been fabricated superconductor(HTS), because It has low surface resistance. The $YBa_2Cu_3O_{7-{\delta}}$(YBCO) films were deposited on MgO substrates$(20{\times}20{\times}0.5mm^3)$ by using pulsed laser deposition and conventional photo-lithographic methods were used to pattern the multiplexer. Epitaxial YBCO films were grown on(100) MgO substrates and showed strongly c_axis orientations observed by X-ray diffraction technique. Superconducting transition temperatures were measured to be about 89K. Simulated results of superconducting multiplexer consisting of hair-pin type filters show the insertion loss of about 1.2dB. The measured frequency response will be compared with the simulated results.

• The Korean Journal of Pain
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• v.14 no.2
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• pp.276-279
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• 2001

Epidural steroid injection is one method of releiving chronic back pain. However, problems with the loss of resistance to air technique include the possible subarachnoid or subdural injection of air resulting in headache, venous air embolism, and the introduction of air bubbles into the epidural space. Pneumocephalus is a rare complication of epidural block for epidural steroid injection. We report a case of a 58-year-old woman who developed a severe headache and posterior nuchal pain with incomplete oculomotor palsy due to pneumocephalus occuring after an epidural steroid injection.

• The Korean Journal of Pain
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• v.25 no.4
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• pp.262-266
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• 2012

Several complications are possible after a lumbar epidural block. However pneumocephalus are rare. In this case, we report a case of pneumocephalus. A 68-year-old male patient received lumbar epidural block with the loss of resistance technique using air, and after 35 minutes, apnea, unconsciousness, hypotension, and bradycardia occurred. Immediately, brain CT was done, and we found pneumocephalus. The patient complained of severe occipital headache and itchiness due to pneumocehalus. After conservative treatment, the patient recovered without neurologic complications, and on the seventh day of his hospitalization, he was discharged from the hospital.