• International Journal of Oral Biology
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• v.34 no.1
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• pp.1-6
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• 2009

The purpose of the present study was to examine the role of peripheral nitric oxide (NO) pathways in the onset of interleukin (IL)-1$\beta$-induced mechanical allodynia in the orofacial area. Experiments were carried out on male Sprague-Dawley rats weighing 230-280 gm and surgical procedures were performed under pentobarbital sodium (40 mg/kg, i.p.). Under anesthesia, a polyethylene tube (PE10) was implanted into the subcutaneous area of one vibrissa pad, which enabled the injection of IL-1$\beta$ or other chemicals. We subcutaneously injected 50 ${\mu}L$ of IL-1$\beta$ into a vibrissa pad through the implanted polyethylene tube with a 100 ${\mu}L$ Hamilton syringe. After the administration of 0.01, 0.1, 1, or 10 pg of IL-1$\beta$, withdrawal behavioral responses were examined. The subcutaneous injection of saline had no effects on the air-puff thresholds. Following the subcutaneous injection of 0.01, 0.1, 1, or 10 pg of IL-1$\beta$, the threshold of air puffs decreased significantly to 12 $\pm$ 3, 7 $\pm$ 2, 5 $\pm$ 1, or 5 $\pm$ 1 psi, respectively, in a dose dependent manner. Pretreatment with L-NAME, a nitric oxide synthase (NOS) inhibitor, blocked IL-1$\beta$-induced mechanical allodynia. However, neither D-NAME, an inactive isomer of L-NAME, nor vehicle affected the IL-1$\beta$-induced mechanical allodynia. Subcutaneous injection of IL-1$\beta$ increased the number of c-fos-like immunoreactive neurons, whereas pretreatment with L-NAME decreased this number, in the trigeminal caudal nucleus. These results suggest that pro-inflammatory cytokines and NO are important contributors to the pathogenesis of persistent and exaggerated IL-1$\beta$-induced pain states. Based on these observations, peripheral application of NOS inhibitors may be of therapeutic value in treating pain disorders in the clinic.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.563-572
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• 1998

An experimental study of hot filament chemical vapor deposition(HFCVD) has been carried out for the fabrication of diamond thin film. Of particular interest is the measurement of deposition uniformity on large substrates. Experimental apparatus including a vacuum chamber, heating elements, etc. has been designed and manufactured. Deposition profiles for different pretreatment powders and different flow rates have been measured in conjunction with the measurement of substrate temperature distribution on a large substrate surface. As the flow rate increases, deposition rate increases, however, the crystallinity becomes worse. Higher growth rate has been found on the region closer to the center location where substrate temperature is higher. The crystallinity has been improved as gas flow rate decreases. The growth rate and morphology of deposition were identified by SEM and the existence of diamond phase was proved by Raman spectroscopy.

• Journal of Fashion Business
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• v.7 no.6
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• pp.50-56
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• 2003

Chitosan has been widely applied to the products in various industries such as textile fabrics, apparels, foods, medical area, etc. Cochineal has long been employed as one of natural dyestuffs in the textile industry. The effect of chitosan pre-treatment on the low-stress physical and mechanical properties of cochineal-dyed fabrics including cotton, silk, nylon and polyester fabrics was investigated in this study. The chitosan treatment and mordanting of the fabrics changed the bending, shear, compression, and surface properties of the fabrics. In cotton fabric specimens, while the increase of B(bending rigidity) of cotton is relatively high, the increase of G(shear rigidity) of cotton is relatively low. In nylon and PET fabric specimens, while the increase tendency of B is relatively low, that of G is high compared to the corresponding cotton fabrics.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.82-90
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• 2009

Disintegration of sewage sludge (SS) was investigated by batch experiments using mechanical pre-treatment. Mechanical disintegration of SS increased the amount of soluble chemical oxygen demand (SCOD), protein and carbohydrate due to the break-up of cell walls. The mechanical disintegration incorporated with alkaline pre-treatment demonstrated higher amount of SCOD compared with mechanical one only. In terms of anaerobic biodegradability, mechanical pretreatment enhanced the anaerobic biodegradation of SS, leading to the methane production improvement. The improvement in BMP for SS treated with mechanical and alkaline-mechanical pre-treatments were 24.1% and 44.5%, respectively. This result suggested that disintegration of SS was effective for improving anaerobic biodegradability.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.565-575
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• 2010

Background: Various decellularization methods have been studied in order to develop tissue graft which is less immunogenic and more durable. This study was performed to investigate the physico-dynamic and histological effect of trypsin pretreatment on decellularization protocols. Material and Method: Two groups of bovine pericardium specimen each underwent decellularization process based on SDS and Triton X-100 or N-lauroylsarcosinate and Triton X-100. Two more groups additionally underwent pretreatment with 0.1% Trypsin/0.1% EDTA. After decellularization process, mechanical tensile strength was tested, then biomechanical test of permeability and compliance was tested before and after fatigue test. Light microscopy and electron microscopy was performed to observe histological findings. Result: There was no difference in mechanical tensile strength between groups, but permeability and compliance was decreased in trypsin pretreated groups. Light microscopic and electron microscopic findings revealed damage of the extracellular matrix in trypsin pretreated groups and in groups which underwent the fatigue test also. Conclusion: Trypsin pretreatment in decellularizing process of bovine pericardium damages extracellular matrix and increases permeability and compliance of the bovine pericardium, but did not decrease tensile strength. Further studies are needed to use enzymatic treatments in decellularization protocols.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.433-439
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• 2022

Background: Repeated administration of opioid analgesics for pain treatment can produce paradoxical hyperalgesia via peripheral and/or central mechanisms. Thus, this study investigated whether spinally (centrally) administered orexin A attenuates opioid-induced hyperalgesia (OIH). Methods: [D-Ala², N-Me-Phe⁴, Gly⁵-ol]-enkephalin (DAMGO), a selective µ-opioid receptor agonist, was used to induce mechanical hypersensitivity and was administered intradermally (4 times, 1-hour intervals) on the rat hind paw dorsum. To determine whether post- or pretreatments with spinal orexin A, dynorphin A, and anti-dynorphin A were effective in OIH, the drugs were injected through an intrathecal catheter whose tip was positioned dorsally at the L3 segment of the spinal cord (5 ㎍ for all). Mechanical hypersensitivity was assessed using von Frey monofilaments. Results: Repeated intradermal injections of DAMGO resulted in mechanical hypersensitivity in rats, lasting more than 8 days. Although the first intrathecal treatment of orexin A on the 6th day after DAMGO exposure did not show any significant effect on the mechanical threshold, the second (on the 8th day) significantly attenuated the DAMGO-induced mechanical hypersensitivity, which disappeared when the type 1 orexin receptor (OX1R) was blocked. However, intrathecal administration of dynorphin or an anti-dynorphin antibody (dynorphin antagonists) had no effect on DAMGO-induced hypersensitivity. Lastly, pretreatment with orexin A, dynorphin, or anti-dynorphin did not prevent DAMGO-induced mechanical hypersensitivity. Conclusions: Spinal orexin A attenuates mechanical hyperalgesia induced by repetitive intradermal injections of DAMGO through OX1R. These data suggest that OIH can be potentially treated by activating the orexin A-OX1R pathway in the spinal dorsal horn.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.371-372
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• 2002

It is well known that red blood cells (RBCs) are suffered from chronic stresses in systemic circulation. The objective of this study is to clarify the effect of the aging of RBCs on rheological properties and hemolysis. Initially, RBCs age fractionation was performed by using a high-speed centrifugation (15[min] at 1500[G]), then young and aged RBCs were suspended in plasma to adjust the hematocrit level of 40[%]. After this pretreatment, the viscosity was measured by using a capillary type and a cone-plate type viscometers, respectively, and the hemolysis test was carried out by a seesaw type shaker. Results from these experiments showed that the viscosity of the aged RBCs measured by the capillary viscometer was increased by 10[%] as compared with that of the young RBCs. Under the condition of all shear zones, the viscosity of the aged RBCs was increased in case of using the cone-plate type viscometer. And the hemolytic level was increased twice as the aging. The data obtained in this study indicated that the ability of aggregation of RBCs was increased and the deformability of RBCs membrane got lower with the aging. Furthermore, it was exhibited that the fragility of RBCs ’ membrane was increased with the aging.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.172-177
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• 1999

Effect of fiber treatment with cellulase (Liftase A40), and with two refining methods (Valley beating and impact refining) on wood fiber and handsheet properties were investigated at three refining levels (300, 400, and 500ml) for two furnishes (NBKP and LBKP). Part of the treated furnishes were classified by 150 mesh screen into fine-free fiber, and fines. Fiber length analysis, WRV, zero-span strength, and other handsheet mechanical properties were compared. The study showed that Liftase A40 lowered the zero-span and the folding endurance of both furnishes (NBKP much more and LBKP much less). Pretreatment with Liftase A 40 followed by refining significantly lowered the fiber length and refining energy to reach to the target freeness. Impact refining, which is done by hitting the fibers vertically with rod at 20% solid content, kept the fiber length increased WRV, and improved handsheet mechanical properties much more than valley beating. Properties of fines from different sources were compared in detail in the study.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.49-57
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• 2019

Biomass, a carbon-neutral fuel, has great advantages because it can replace fossil fuels to reduce greenhouse gas emissions. However, due to its low density, high water content, and hydrophilicity, biomass has disadvantages for transportation and storage. To improve these properties, a pretreatment process of biomass is required. One of the various pre-treatment technologies, torrefacion, makes biomass similar to coal through low-temperature pyrolysis. In this study, torrefacion treatment was carried out at 200, 230, 250, 280, and $300^{\circ}C$ for wood pellet, empty fruit bunch (EFB) and kenaf, and the feasibility of replacing coal with fuel was examined. Hygroscopicity tests were conducted to analyze the hydrophobicity of biomass, and its chemical structure changes were investigated using Infrared spectrum analysis. It was confirmed that the hygroscopicity was decreased gradually as the torrefacion temperature increased according to the hygroscopicity tests. The hydrophilicity was reduced according to the pyrolysis of hemicellulose, cellulose, and lignin of biomass.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.311-317
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• 1996

Background: Following peripheral nerve injury, rats will show a tactile allodynia and hyperalgesia. But the mechanism of allodynia is still obscure. Previous studies have shown this allodynia was reversed by intrathecal alpha-2 agonists and NMDA antagonists, but not by morphine. In formalin test, either the pretreatment of NMDA antagonist or morphine prevents the hyperalgesia. The present studies, using rats rendered allodynic by ligation of the left L5 and L6 nerves, aimed to investigate the effects of pretreatment of MK-801 and morphine on the development of tactile allodynia. Methods and Material: Male Sprague-Dawley rats (100~150g) were anesthetized with halothane, the left L5 and L6 spinal nerves were ligated tightly by 6-0 black silk. For sham operation muscle dissection was performed but the spinal nerve was not ligated. For pretreatment of drugs, MK-801 (NMDA antagonist; 0.3 mg/kg). CNQX (non-NMDA) antagonist; 0.3 mg/kg), morphine (1 mg/kg) or saline (placebo) was administered subcutaneously 30 minutes before operation. A second dose was administered subcutaneously 24 hours after operation and further doses were given daily for 2 days further. The volume of injection was 5 ml/kg. To assess the mechanical allodynia, paw withdrawal thresholds of ipsilateral limb were determined using 8 von Frey hairs. Results: Within 2 days saline, CNQX or morphine injected rats developed tactile allodynia (paw withdrawal threshold was about 2g), and persisted for over 2 weeks. Pretreatment of MK-801 delayed the development of tactile allodynia for 3 days comparing to that of saline injected rat. Conclusion: NMDA receptor in the central nerve system plays an important role in the development of tactile allodynia induced by peripheral nerve injury. But the mechanism may be different from hyperalgesia developed in formalin test.