• Polymer(Korea)
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• v.32 no.2
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• pp.116-124
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• 2008

A commercialized biobased and biodegradable poly(lactic acid)(PLA) containing the functional monomer of glycidyl methacrylate (GMA) was chemically modified using reactive extrusion to enhance its melt strength. Modified PLAs were prepared with various contents of GMA and initiator, and were characterized by observing their gel fraction, thermal properties, melt viscoelasticity and biodegradability. The complex viscosity and storage modulus of chemically modified PLA with the initiator alone was increased by addition of initiator and were more increased in the presence of GMA. There was a optimum content of GMA showing the maximum complex viscosity with the amount of initiator. The biodegradebility of modified PLA was slightly decreased by addition of GMA.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.169-175
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• 2012

In the study, the effects of $130{\sim}150^{\circ}C$ annealing condition and 1~10 wt% isopropylphenyl diphenyl phosphate (IPPP) on crystallization behavior and flame retardancy of a full name (PLA) film were determined. The crystallization kinetics of PLA films with adding 1, 5, and 10 wt% IPPP at $140^{\circ}C$ were higher than those at 130 and $150^{\circ}C$. The average crystallinity and crystallite size of PLA film with 1 wt% IPPP were 21.3% and 24.8 nm, respectively. With an increasing IPPP content, the crystallinity of PLA film increased and the crystallite size decreased. The burning rate lowered with an increasing IPPP content as well.

• Tuberculosis and Respiratory Diseases
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• v.56 no.6
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• pp.638-645
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• 2004

Background : Uteroglobin is a protein produced by the normal bronchial epithelium and its expression level is lower in non-small cell lung cancer tissues and cell lines. It mainly functions as an anti-inflammatory, and when it is overexpressed in cancer cells, the neoplastic phenotype is antagonized. cPLA2 and COX-2, which are also associated with inflammation, were reported to be related to cancer. The relationship between cPLA2, COX-2 and uteroglobin is unclear. The relationship between uteroglobin and ERK, which is related to cell growth, is also not unclear. This study investigated the changes in the cPLA2 and COX-2 expression levels and the ERK activities after the overexpression of uteroglobin in non-small cell lung cancer cell lines. Methods : The A549 and NCI-H460 cell lines were infected by adenovirus-null and adenovirusuteroglobin. The cChange in the cPLA2, COX-2 expression level and ERK activity after uteroglobin overexpression was measured by Western blot. The change in MMP activity was measured by zymography. Results : Western blot revealed decreased expression levels of cPLA2, and COX-2, and increased pERK levels in nonsmall cell lung cancer cells after uteroglobin overexpression. Zymography revealed no changes in the MMP-2 activity and lower MMP-9 activity. U0126, which is a specific inhibitor of ERK-activating kinase MEK-1/-2, prevented the decrease in the MMP-9 activity Conclusions : A decrease in cPLA2 expression, COX-2 expression, MMP-9 activity and a increase in ERK activity may be related to the anticancer effects of uteroglobin in nonsmall cell lung cancer cells.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.416-422
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• 2020

In this study, eco-friendly biodegradable materials were prepared using poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and hydrogenated castor oil power (HCO) as an additive. The prepared PLA/PBAT/HCO blended films were characterized by the scanning electron microscope (SEM) and fourier-transform infrared spectroscopy (FT-IR). The results of SEM analysis indicated that PLA/PBAT (8 : 2) blended films added HCO showed no rough area, crack, or large agglomeration when compared with those adding various additives (12-hydroxy stearic acid (12HSA) and cellulose). The FT-IR results indicated the presence of specific peak of HCO in the PLA/PBAT blended films, and its peak intensity increased with increasing HCO content (0~5.0 wt%). Tensile strength, elongation at break, and water barrier and thermal properties of the prepared PLA/PBAT/HCO blended films were also investigated, indicating that the physical and thermal properties was improved more than three times by the addition of HCO. The biodegradability test in soil revealed that the prepared biodegradable materials were degraded by about 6.0~20% after 90 days.

• Tuberculosis and Respiratory Diseases
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• v.71 no.2
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• pp.97-105
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• 2011

Background: It was hypothesized that the immunomodulating effects of moxifloxacin contribute to ameliorate oleic acid (OA)-induced acute lung injury (ALI) by suppression of cytosolic phospholipase A2 (cPLA2). This was based on observations from experiments on rats associated with neutrophilic respiratory burst, cPLA2 activity, and expressions of cPLA2, $TNF{\alpha}$, and COX-II in the lung. Methods: ALI was induced by intravenous injection of OA in male Sprague-Dawley rats. Five hours after OA injection, protein content in bronchoalveolar lavage (BAL), lung myeloperoxidase (MPO) activity, and numbers of BAL neutrophils were measured. As an index of oxidative stress-induced lung injury, the content of malondialdehyde (MDA) in lung tissues was also determined. Lung histology, immunohistochemistry and determination of activity of cPLA2 in lung tissues were carried out. In addition, Western blotting of $TNF{\alpha}$ and COX-II in lung tissues was performed. Results: The accumulation of neutrophils in the lungs was observed after OA injection. BAL protein was increased along with neutrophilic infiltration and migration by OA. Moxifloxacin decreased all of these parameters of ALI and ameliorated ALI histologically. The increased malondialdehyde (MDA) in the lung by OA was also decreased by moxifloxacin. Moxifloxacin not only suppressed cPLA2 expression in the lungs and neutrophils but also decreased cPLA2 activity in lung tissues of rats given OA. The enhanced expressions of $TNF{\alpha}$ and COX-2 in the lung tissues of rats given OA were also suppressed by moxifloxacin. Conclusion: Moxifloxacin inhibited cPLA2 and down-regulated $TNF{\alpha}$ and COX-2 in the lungs of rats given OA, which resulted in the attenuation of inflammatory lung injury.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.31-39
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• 1990

An optimization problem of AND-EXOR PLA's with input decoders can be regarded as a minimization problem of Exclusive-Or Sum-Of-Products expressions (ESOP's) for multiple-valued input two-valued output functions. In this paper, We propose a minimization algorithm for ESOP's. The algorithm is based on an iterative improvement. Five rules are used to replace a pair of products with another one. We minimized many ESOP's for arithmetic circuits. In most cases, ESOP's required fewer products than SOP's to realized same functions.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4727-4731
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• 2013

Background: There have been no large-scale population-based studies to estimate the subsequent risk of primary liver cancer (PLC) among patients with pyogenic liver abscess (PLA). This study aimed to provide relevant data. Materials and Methods: The Taiwan Longitudinal Health Insurance Database for the years 2000 and 2005 was used. The PLA group were adult inpatients who were newly diagnosed with PLA from 2000 to 2008. The control group was randomly selected and matched with the PLA group in terms of age, sex, and date in which medical treatment was sought other than for PLA. Results: There were 1,987 patients each in the PLA and control groups. In total, 56 had PLC, 48 (2.4%, 601.5 per 100,000 person-years) from the PLA group, and 8 from the control group. After adjusting for potential covariates, the hazard ratio of PLC for the PLA group was 3.4 times that of the control group (95% confidence interval = 1.6-7.3, p <0.001). The PLC risk for the PLA group was significantly higher within the first year after PLA diagnosis (hazard ratio: 35.4) as compared with the control group and became insignificant (hazard ratio: 2.0, 95% confidence interval = 0.8-4.9) more than one year after PLA diagnosis. Conclusions: Patients with PLA have a higher rate of PLC than matched controls, especially within the first year after the diagnosis of PLA, suggesting PLA is a warning sign for PLC.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.79-86
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• 2023

In this study, poly(lactic acid) (PLA) and Poly(butylene-adipate-co-terephthalate) (PBAT) composite films containing calcined oyster shell powder (OSP) were evaluated for the applicability of antimicrobial packaging. PLA/PBAT-OSP composite films were prepared using twin-screw extruder. The OSP composite was incorporated into PLA/PBAT blend with different ratios (0, 1, 3, 5 and 10%) and the effect of OSP in the PLA/PBAT matrix was evaluated. The PLA/PBAT-OSP composite films were evaluated for properties using FT-IR, SEM, TGA, DSC, UTM, UV-vis, and Contact angle, as well as antimicrobial property was examined according to ISO 22196 - Antimicrobial Plastic Test. As OSP was added, it showed high antimicrobial activities for both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. On the other hand, it was found that mechanical properties decreased as OSP was added. For the application of PLA/PBAT-OSP composite films as an antimicrobial packaging material, it is necessary to improve the dispersibility of OSP in the PLA/PBAT composite films and their physical properties at the same time.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.263-273
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• 1999

The role of phospholipase $A_2\;(PLA_2)$ in acute lung leak induced by intestinal ischemia was investigated in association with neutrophilic respiratory burst. To induce lung leak, we generated intestinal ischemia for 60 min prior to the 120 min reperfusion by clamping superior mesenteric artery in Sprague-Dawley rats. Acute lung leak was confirmed by the increased lung leak index and protein content in bronchoalveolar fluid. These changes were inhibited by mepacrine, the non-specific $PLA_2$ inhibitor. The lung myeloperoxidase (MPO) activity denoting the pulmonary recruitment of neutrophils was increased by intestinal I/R, but decreased by mepacrine. Simultaneously, the number of leukocytes in bronchoalveolar fluid was increased by intestinal ischemia/reperfusion (I/R) and decreased by mepacrine. Gamma glutamyl transferase activity, an index of oxidative stress in the lung, was increased after intestinal I/R but decreased by mepacrine, which implicates that $PLA_2$ increases oxidative stress caused by intestinal I/R. The $PLA_2$ activity was increased after intestinal I/R not only in the intestine but also in the lung. These changes were diminished by mepacrine. In the cytochemical electron microscopy to detect hydrogen peroxide, intestinal I/R increased the generation of the hydrogen peroxide in the lung as well as in the intestine. Expression of interleukin-1 (IL-1) in the lung was investigated through RT-PCR. The expression of IL-1 after intestinal I/R was enhanced, and again, the inhibition of $PLA_2$ suppressed the expression of IL-1 in the lung. Taken together, intestinal I/R seems to induce acute lung leak through the activation of $PLA_2$, the increase of IL-1 expression associated with increased oxidative stress by neutrophilic respiratory burst.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.165-174
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• 2017

This study reports a synthesis of an amphiphilic linear block copolymer consisting of a hydrophobic poly (lactide) (PLA) block and a hydrophilic hyperbranched polyglycerol (hbPG) block, PLA-b-hbPG. Simple chemical modification of the hbPG block with 4-hydroxycinnamic acid (CA) led to a photo-crosslinkable block copolymer, PLA-b-hbPG-CA. Nanosized micelles of the block copolyemrs were used as drug carriers for sustainable release. The hbPG shell made of a small molecular weight hbPG block showed excellent hydrophilicity, which can minimize in vivo toxicity. The UV-crosslinked PLA-b-hbPG-CA micelles loaded with drugs colud be served as a drug delivery carrier for its biocompatibility and self-assembled structures.