• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.400-404
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• 2007

The objective of this study was to analyze change of soil organic matter fraction from a range of livestock manure compost that differed in their total C, N content and C quality, to gain a better understanding of their influence on soil organic matter. The chicken (CHM), pig (PIM), and cow (COM) manure-based composts, and manure-sawdust-based composts (CHMS, PIMS, and COMS) were applied annually to the upland soil with $3Mg\;C\;ha^{-1}$ during 4 years. After 4 years, the soil carbon content was increased to 25-30 and 40% for manure-based compost and manure-sawdust-based compost compared to control. In the all treatments, the content of light fraction C was sharply increased after second year. The content of light fraction C in the manure-sawdust-based compost was higher than in the manure-based compost. By contrast, the content of heavy fraction C was higher in the manure-based compost than in the manure-sawdust-based compost. These results indicate that stabilization of carbon applied from microbiological process was faster in the manure-based compost than in the manure-sawdust-based compost.

• Anxiety and mood
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• v.8 no.1
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• pp.22-30
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• 2012

Objective : We investigated whether Posttraumatic stress disorder patients have a higher tendency to exaggerate the extent of their psychological symptoms compared to other psychiatric patients. Methods : Medical records of patients, who had received psychiatric treatment at four university hospitals in Korea between January 2009 and December 2010, were retrospectively reviewed. We compared a group of 37 patients diagnosed with PTSD, and another group of 41 patients diagnosed with neurotic, stress-related and somatoform disorders according to the ICD-10. To compare the extent of malingering in the two groups, we compared the validity scales of MMPI-2 and Personality Assessment Inventory. We determined the number of participants in both groups feigning their responses by using various cutoff scores of the validity indicators. Results : The PTSD group showed significantly higher scores on the F (p=0.001), F (B)(p=0.000), F (P)(p=0.030), F-K (p=0.003) scale of the MMPI-2 compared to the other group of psychiatric patients. The PTSD group had a significantly higher NIM score (p=0.001) but a lower PIM score (p=0.020) of the PAI compared to the other group of psychiatric patients. Using the cutoff scores, the PTSD group showed a significantly higher number of patients who feigned responses compared to the other group ($Fb{\geq}75$ (p=0.010), $F-K{\geq}1$ (p=0.005), $F-K{\geq}10$ (p=0.011) from the MMPI-2, and $NIM{\geq}80$ (p=0.001) from the PAI). Conclusion : These results suggest that PTSD patients have a tendency to exaggerate their symptom. This group of patients overreported the severity of their condition during standardized personality assessment that included the MMPI-2 or PAI compared to patients diagnosed with other psychiatric disorders. Additional research is required to determine the factors influencing symptom exaggeration in PTSD.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.218-228
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• 2010

Components of dental resin-based restorative materials are reported to leach from the filling materials even after polymerization. Hydroquinone (HQ) is one of the major monomers used in the dental resin and is known as a carcinogen. Thus, carcinogenic risk of HQ leaching from the dental resin becomes a public health concern. The present study attempted to examine the carcinogenic potentials of HQ on the human epithelial cell, which is the target cell origin of the most of oral cancers. Cytotoxicity of HQ was observed above 50${\mu}M$ as measured by LDH assay, indicating a relatively low toxicity of this substance in human epithelial cells. The parameters of neoplastic cellular transformation such as cell saturation density, soft agar colony formation and cell aggregation were analyzed to examine the carcinogenic potential of HQ. The study showed that 2-week exposure of HQ showed the tendency of increase in the saturation density and the significant enhancement of soft agar colony formation at the highest dose, 50 ${\mu}M$ only. It is suggested that HQ has a weak potential of carcinogenicity. When cells were treated with HQ and TPA, a well-known tumor promoter, the parameters of neoplastic cellular transformation was significantly increased. This result indicates that the potential risk of carcinogenicity from HQ is largely dependent upon the presence of promoter. Exposure of 50 ${\mu}M$ HQ increased the time-dependent apoptosis as measured by the ELISA kit. This concentration coincides with a dose of neoplastic transformation, indicating a possible link between apoptosis and HQ-induced cellular transformation. Hydroquinone generated Reactive Oxygen Species (ROS) which was evidenced by the treatment of antioxidants such as trolox and N-acetyl cysteine and the GSH depleting agent, BSO. Antioxidants blocked the generation of ROS and the GSH depleting agent, BSO dramatically increased the ROS production. Since HQ is known to increase ROS production thru activation of transcriptional factor such as c-Myb and Pim-1, it is speculated that ROS generation by HQ plays a role in the activation of oncogene, which may lead to neoplastic transformation. In addition, ROS is involved in the alteration of signal transduction, which regulates the apoptosis in many cellular systems. Thus, ROS-mediated apoptosis may be involved in the HQ-induced carcinogenic processes. Protein kinase C (PKC) is known to play pivotal roles in neoplastic transformation of cells and its high expression is often found in a variety of types of tumors including oral cancer. PKC translocation of PKC-${\alpha}$ was observed following HQ exposure. Altered signaling system may also play a role in the transformation process. Taken together, HQ leached from the dental resin does not pose a significant threat as a cancer causing agent, but its carcinogenic potential can be significantly elevated in the presence of promoter. The mechanism of HQ-induced carcinogenesis involved ROS generation, apoptosis and altered signaling pathway. The present study will provide a valuable data to estimate the potential risk of HQ as a carcinogen and understand mechanism of HQ-induced carcinogenesis in human epithelial cells.