• Korean Journal of Radiology
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• v.2 no.1
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• pp.1-7
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• 2001

Objective: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. Materials and Methods: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2^*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calculated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. Results: Mean rCBV ratios were 4.90°±1.01 for glioblastomas, 3.97°±0.56 for anaplastic gliomas and 1.75°±1.51 for low-grade gliomas, and were thus significantly different; p < .05 between glioblastomas and anaplastic gliomas, p < .05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblastomas and low-grade gliomas. The rCBV ratio cutoff value which permitted discrimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. Conclusion: Perfusion MR imaging is a useful and reliable technique for estimating the histologic grade of gliomas.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.31-56
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• 2024

Pig farming, a vital industry, necessitates proactive measures for early disease detection and crush symptom monitoring to ensure optimum pig health and safety. This review explores advanced thermal sensing technologies and computer vision-based thermal imaging techniques employed for pig disease and piglet crush symptom monitoring on pig farms. Infrared thermography (IRT) is a non-invasive and efficient technology for measuring pig body temperature, providing advantages such as non-destructive, long-distance, and high-sensitivity measurements. Unlike traditional methods, IRT offers a quick and labor-saving approach to acquiring physiological data impacted by environmental temperature, crucial for understanding pig body physiology and metabolism. IRT aids in early disease detection, respiratory health monitoring, and evaluating vaccination effectiveness. Challenges include body surface emissivity variations affecting measurement accuracy. Thermal imaging and deep learning algorithms are used for pig behavior recognition, with the dorsal plane effective for stress detection. Remote health monitoring through thermal imaging, deep learning, and wearable devices facilitates non-invasive assessment of pig health, minimizing medication use. Integration of advanced sensors, thermal imaging, and deep learning shows potential for disease detection and improvement in pig farming, but challenges and ethical considerations must be addressed for successful implementation. This review summarizes the state-of-the-art technologies used in the pig farming industry, including computer vision algorithms such as object detection, image segmentation, and deep learning techniques. It also discusses the benefits and limitations of IRT technology, providing an overview of the current research field. This study provides valuable insights for researchers and farmers regarding IRT application in pig production, highlighting notable approaches and the latest research findings in this field.

• Progress in Medical Physics
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• v.11 no.2
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• pp.157-165
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• 2000

Purpose: For estimation of yields of l)NA damages induced by radiation and enhanced by oxygen, a mathematical model was used and tested. Materials and Methods: Reactions of the products of water radiolysis were modeled as an ordinary time dependant equations. These reactions include formation of radicals, DNA damage, damage repair, restitution, and damage fixation by oxygen and H-radical. Several rate constants were obtained from literature while others were calculated by fitting an experimental data. Sensitivity studies were performed changing the chemical rate constant at a constant oxygen number density and varying the oxygen concentration. The effects of oxygen concentration as well as the damage fixation mechanism by oxygen were investigated. Oxygen enhancement ratio(OER) was calculated to compare the simulated data with experimental data. Results: Sensitivity studies with oxygen showed that DNA survival was a function of both oxygen concentration and the magnitude of chemical rate constants. There were no change in survival fraction as a function of dose while the oxygen concentration change from 0 to 1.0 x 10$^{7}$ . When the oxygen concentration change from 1.0 $\times$ 107 to 1.0 $\times$ 101o, there was significant decrease in cell survival. The OER values obtained from the simulation study were 2.32 at 10% cell survival level and 1.9 at 45% cell survival level. Conclusion: Sensitivity studies with oxygen demonstrated that the experimental data were reproduced with the effects being enhanced for the cases where the oxygen rate constants are largest and the oxygen concentration is increased. OER values obtained from the simulation study showed good agreement for a low level of cell survival. This indicated that the use of the semi-empirical model could predict the effect of oxygen in cell killing.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.330-335
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• 2007

This study was performed to investigate the anti-diabetic mechanism of crude polysaccharides isolated from the fruiting bodies of Grifola frondosa. We treated 3T3-L1 adipocyte cells to observe whether the crude polysaccharides isolated from Grifola frondosa would stimulate insulin sensitivity. Significant insulin sensitizing activity was observed in the 3T3-L1 adipocytes, and giving the crude polysaccharide of Grifola frondosa with 1 nM of insulin caused glucose uptake to increase to a similar level as giving 50 nM of insulin alone. To confirm the mechanism for the anti-diabetic effect of the crude polysaccharides, we performed further examinations within $KK-A^{y}$ mice, an animal model of type 2 diabetes. The crude polysaccharides reduced blood glucose levels in the $KK-A^{y}$ mice for 2 weeks after feeding, and also significantly lowered plasma insulin levels. These results suggest that the anti-diabetic mechanism of the crude polysaccharide of Grifola frondosa is related to the enhancement of insulin sensitivity.

• Tuberculosis and Respiratory Diseases
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• v.67 no.4
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• pp.318-324
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• 2009

Background: A diagnosis and treatment of chest wall tuberculosis (CWTB) is both difficult and controversial. The aim of this study was to collect information on the optimal treatment for CWTB. Methods: The clinical features, radiographic findings, and treatment outcomes of 26 patients, who underwent surgery and were diagnosed histopathologically, were retrospectively analyzed. Results: The most common presenting symptom was a palpable mass found in 24 patients (92.3%). In all patients, CT revealed a soft tissue mass that was accompanied by a central low density, with or without peripheral rim enhancement. The sensitivity and specificity of the bone scintigram for bone involvement were 87.5% and 100%, respectively. CWTB was diagnosed preoperatively by aspiration cytology and smear for acid-fast bacilli in five out of 11 patients. Twenty-three patients (88.5%) underwent a radical excision and three underwent incision/drainage or an incisional biopsy. The duration of antituberculous medication was 7.5${\pm}$3.98 months with a follow-up period of 28.2${\pm}$26.74 months. Among the 20 patients who completed their treatment, nine received chemotherapy for six months or less and 11 received chemotherapy for nine months or more. Two patients had a recurrence four and seven months after starting their medication. Conclusion: A 6 month regimen may be appropriate for CWTB patients who have undergone a complete excision.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.151-151
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• 2009

Recently, there has been increasing interest in amorphous oxide semiconductors to find alternative materials for an amorphous silicon or organic semiconductor layer as a channel in thin film transistors(TFTs) for transparent electronic devices owing to their high mobility and low photo-sensitivity. The fabriction of amorphous oxide-based TFTs at room temperature on plastic substrates is a key technology to realize transparent flexible electronics. Amorphous oxides allows for controllable conductivity, which permits it to be used both as a transparent semiconductor or conductor, and so to be used both as active and source/drain layers in TFTs. One of the materials that is being responsible for this revolution in the electronics is indium-zinc-tin oxide(IZTO). Since this is relatively new material, it is important to study the properties of room-temperature deposited IZTO thin films and exploration in a possible integration of the material in flexible TFT devices. In this research, we deposited IZTO thin films on polyethylene naphthalate substrate at room temperature by using magnetron sputtering system and investigated their properties. Furthermore, we revealed the fabrication and characteristics of top-gate-type transparent TFTs with IZTO layers, seen in Fig. 1. The experimental results show that by varying the oxygen flow rate during deposition, it can be prepared the IZTO thin films of two-types; One a conductive film that exhibits a resistivity of $2\times10^{-4}$ ohm${\cdot}$cm; the other, semiconductor film with a resistivity of 9 ohm${\cdot}$cm. The TFT devices with IZTO layers are optically transparent in visible region and operate in enhancement mode. The threshold voltage, field effect mobility, on-off current ratio, and sub-threshold slope of the TFT are -0.5 V, $7.2\;cm^2/Vs$, $\sim10^7$ and 0.2 V/decade, respectively. These results will contribute to applications of select TFT to transparent flexible electronics.

• Archives of design research
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• v.18 no.4 s.62
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• pp.215-224
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• 2005

With the recent increase of sensitivity to decors, there has been an ever-increasing significance of exhibiting the beauty of the outer looks of an article. This trend has necessarily led to the diversification and also specialization of the color scheme activities. And so, it is inevitable that we should form the substantial ideas of the color scheme and further on, enhance the efficacy of its orientation under the prevailing circumstances. Now, we come to a realization that we must first take a glance at the whole picture of the arrays of color embedded in a variety of articles in the sixties and seventies of the 20th century, a bold introduction of color designs, thereby tracing the birth of color designs and finding a meaning in its mechanism. This study begins with the obtaining of a large collection of articles in those days, along with the literature on the commercial effects color suggest, and looking into the background of their trend and finding a meaning that underlies what these colors suggest. The general idea of those color designs exemplifies that the color selection was none other than the simplicity and convenience in the making of things in doser relation to the easy selling. With the advance of material quality and enhancement of the industrial idealism, it has been proved that color plays an important role in depicting the image of quality and tastes of class. In that role color has been given the indicator of visual delights and differentials in quality articles. All this has been reflected in a diversity of articles: for instance, white for household appliances, prime color for living necessaries and natural color for the decore like furniture. Formerly, after all, people used to have little regard for color. What is color for, it was thought, in relation to the selling image of articles? That is wily our preceding generation pays attention only to the first-hand looks of articles, neglecting the intensive study on color. We are beginning to understand what image a certain color scheme evokes in our feeling.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.207-213
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• 2013

BACKGROUND: This study was conducted to develop analytical method with reproducibility, accuracy and applicability to agricultural products than the existing methods. METHODS AND RESULTS: Mean recoveries of thidiazuron ranged from 89.2 to 91.2 in hulled rices, 87.2 to 92.1 in peppers, from 76.4 to 86.9 in potatoes, from 91.2 to 95.7 in watermelons, from 86.5 to 88.5 in kiwi fruits, and from 89.5 to 94.0 in grapes, with less than 10% of relative standard deviations. In addition, the limit of quantitation was set to be 0.05 mg/kg and there were no interfering peaks in integrating the thidiazuron peak. CONCLUSION(S): These results represent that the enhanced analytical method has reliable accuracy, precision, selectivity, and sensitivity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.809-819
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• 2020

In this study, the twist angle and wing planform shapes were selected as design variables and optimized to secure the stability of the flying-wing type UAV. Flying-wing aircraft has no separated fuselage and tails, which has advantages in aerodynamic characteristics and stealth performance, but it is difficult to secure the flight stability. In this paper, the sweep back angle and twist angle were optimized to obtain the lateral stability, the static margin and wing planform shapes were optimized to improve the longitudinal stability of the flying-wing, then effect of the twist angle was confirmed by comparing the stability of the shape with the winglet and the shape with the twist angle. In the optimization formulation, focusing on improving stability, constraints were established, objective functions and design variables were set, then design variable sensitivity analysis was performed using the Sobol method. AVL was used for aerodynamic analysis and stability analysis, and SQP was used for optimization. The CFD analysis of the optimized shape and the simulation of the dynamic stability proved that the twist angle can be applied to the improvement of the lateral stability as well as the stealth performance in the flying-wing instead of the winglet.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.324-325
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• 2014

Quantum wells infrared photodetectors (QWIPs) have been used to detect infrared radiations through the principle based on the localized stated in quantum wells (QWs) [1]. The mature III-V compound semiconductor technology used to fabricate these devices results in much lower costs, larger array sizes, higher pixel operability, and better uniformity than those achievable with competing technologies such as HgCdTe. Especially, GaAs/AlGaAs QWIPs have been extensively used for large focal plane arrays (FPAs) of infrared imaging system. However, the research efforts for increasing sensitivity and operating temperature of the QWIPs still have pursued. The modification of heterostructures [2] and the various fabrications for preventing polarization selection rule [3] were suggested. In order to enhance optical performances of the QWIPs, double barrier quantum well (DBQW) structures will be introduced as the absorption layers for the suggested QWIPs. The DBWQ structure is an adequate solution for photodetectors working in the mid-wavelength infrared (MWIR) region and broadens the responsivity spectrum [4]. In this study, InGaAs/GaAs/AlGaAs double barrier quantum well infrared photodetectors (DB-QWIPs) are successfully fabricated and characterized. The heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIPs are grown by molecular beam epitaxy (MBE) system. Photoluminescence (PL) spectroscopy is used to examine the heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIP. The mesa-type DB-QWIPs (Area : $2mm{\times}2mm$) are fabricated by conventional optical lithography and wet etching process and Ni/Ge/Au ohmic contacts were evaporated onto the top and bottom layers. The dark current are measured at different temperatures and the temperature and applied bias dependence of the intersubband photocurrents are studied by using Fourier transform infrared spectrometer (FTIR) system equipped with cryostat. The photovoltaic behavior of the DB-QWIPs can be observed up to 120 K due to the generated built-in electric field caused from the asymmetric heterostructures of the DB-QWIPs. The fabricated DB-QWIPs exhibit spectral photoresponses at wavelengths range from 3 to $7{\mu}m$. Grating structure formed on the window surface of the DB-QWIP will induce the enhancement of optical responses.