• Elastomers and Composites
• /
• v.58 no.3
• /
• pp.128-135
• /
• 2023

To improve the adhesive strength of natural rubber (NR) for a seismic isolation damper, citraconic acid-g-NR (CCA-g-NR) was synthesized via the melt grafting of citraconic acid (CCA) onto NR using an azobisisnomerobutyronitrile (AIBN) initiator. Subsequently, the influence of CCA and AIBN concentrations on the graft ratio G/R (%) and graft efficiency G/E (%) of the CCA-g-NR was investigated. The optimum CCA and AIBN concentrations required to achieve the desired G/R (3.49%) and G/E (49.8%) were found to be 7 phr and 0.13 phr, respectively. Additionally, we studied the influence of CCA-g-NR concentration on the mechanical properties (tensile strength, elongation at break, and modulus at 300%), adhesive strength, and cure characteristics of the rubber compound in the seismic isolation damper. As the concentration of CCA-g-NR increased, the elongation at break and adhesive strength of the compound increased, whereas its tensile strength and modulus at 300% decreased. Moreover, as the concentration increased, the maximum torque decreased and the scorch time was delayed to obtain an optimal vulcanization time.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.9
• /
• pp.1538-1545
• /
• 2007

Clavulanic acid (CA) is an inhibitor of ${\beta}$-lactamase that is produced from Streptomyces clavuligerus NRRL3585 and is used in combination with other antibiotics in clinical treatments. In order to increase the production of CA, the replicative and integrative expressions of ccaR (encoding for a specific regulator of the CA biosynthetic operon) and cas2 (encoding for the rate-limiting enzyme in the CA biosynthetic pathway) were applied. Six recombinant plasmids were designed for this study. The pIBRHL1, pIBRHL3, and pIBRHL13 were constructed for overexpression, whereas pNQ3, pNQ2, and pNQ1 were constructed for chromosomal integration with ccaR, cas2, and ccaR-cas2, respectively. All of these plasmids were transformed into S. clavuligerus NRRL3585. CA production in transformants resulted in a significantly enhanced amount greater than that of the wild type, a 2.25-fold increase with pIBRHLl, a 9.28-fold increase with pNQ3, a 5.06-fold increase with pIBRHL3, a 2.93-fold increase with pNQ2 integration, a 5.79-fold increase with pIBRHLl3, and a 23.8-fold increase with pNQ1. The integrative pNQl strain has been successfully applied to enhance production.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.2
• /
• pp.116-120
• /
• 2006

We constructed four recombinant plasm ids to enhance the production of clavulanic acid (CA) in Streptomyces clavuligerus NRRL3585: (1) pIBRHL1, which includes ccaR, a pathway-specific regulatory gene involved in cephamycin C and CA biosynthesis; (2) pIBRHL2, containing claR, again a regulatory gene, which controls the late steps of CA biosynthesis; (3) pGIBR containing afsR-p, a global regulatory gene from Streptomyces peucetius; and (4) pKS, which harbors all of the genes (ccaR/ claR/ afsR-p). The plasmids were expressed in S. clavuligerus NRRL3585 along with the $ermE^*$ promoter. All of them enhanced the production of CA; 2.5-fold overproduction for pIBRHL1, 1.5-fold for pIBRHL2, 1.6-fold for pGIBR, and 1.5-fold for pKS compared to the wild type.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.13
• /
• pp.5443-5447
• /
• 2014

The cholangiocarcinoma (CCA) is a relatively rare cancer worldwide but it is highly prevalent in Thailand where the liver fluke, Opisthorchis viverrini is endemic. There are reports that interleukin 6 (IL-6) may play an important role in the pathogenesis of opisthorchiasis associated CCA. Functionally, IL-6 can act on target cells through its receptor, IL-6R, and IL-6R polymorphisms may affect the functional activity of IL-6 leading to susceptibility to cholangiocarcinogenesis. Therefore, we assessed the association of the 48892 A/C (Asp358Ala) polymorphism in exon 9 of the IL-6R gene in 79 CCA cases compared to 80 healthy controls using the PCR-RFLP technique. The results showed significant differences between CCA cases and controls in overall genotype (p=0.001) and allele frequencies (p=0.0002). Chi-square for trend test revealed a significant association between genotype and CCA susceptibility (p=0.0002). The odds ratios (ORs) for genotype were 0.283 (95% CI=0.131-0.605, AC vs. AA; p=0.0003) and 0.206 (95% CI=0.196-1.245, CC vs. AA; p=0.0416), the OR for alleles was 0.347 (95% CI=0.187-0.633, allele C vs. allele A; p=0.0002) and that for the carrier C variant was 0.272 (95% CI=0.130-0.564; p=0.0001). This study demonstrated a close association between an IL-6R polymorphism, specifically higher A allele, and cholangiocarcinoma.

• Journal of Yeungnam Medical Science
• /
• v.40 no.1
• /
• pp.65-77
• /
• 2023

Background: This study aimed to compare clinical outcomes between surveillance and adjuvant therapy (AT) groups after R0 resection for cholangiocarcinoma (CCA). Methods: A total of 154 patients who underwent R0 resection for CCA at the Daegu Catholic University Medical Center between January 2010 and December 2019 were included. Overall survival (OS) and progression-free survival (PFS) were analyzed. Results: The median follow-up duration was 899 days. There were 109 patients in the AT group and 45 patients in the surveillance group. The patients in the AT group were younger (67 years vs. 74 years, p<0.001) and included more males (64.2% vs. 46.7%, p=0.044). The proportion of patients with stage III CCA was larger in the AT group than in the surveillance group (13.8% vs. 2.2%, p=0.005). In addition, AT did not improve OS (5-year OS rate, 69.3% in the AT group vs. 64.2% in the surveillance group, p=0.806) or PFS (5-year PFS rate, 42.6% in the AT group vs. 48.9% in the surveillance group, p=0.113). In multivariate analysis using the Cox proportional hazards model, stage III CCA (hazard ratio [HR], 10.81; 95% confidence interval [CI], 2.92-40.00; p<0.001) was a significant predictor of OS. American Society of Anesthesiologists classification II (HR, 0.50; 95% CI, 0.31-0.81; p=0.005), and American Joint Committee on Cancer stages II (HR, 3.14; 95% CI, 1.25-7.89; p=0.015) and III (HR, 8.08; 95% CI, 2.80-23.32; p<0.001) were independent predictors of PFS. Conclusion: AT after R0 resection for CCA did not improve OS or PFS.

• Parasites, Hosts and Diseases
• /
• v.60 no.4
• /
• pp.261-271
• /
• 2022

This study provides an overview of the current status of clonorchiasis and cholangiocarcinoma (CCA), and their relationship in Korea during 2012-2020. Data were obtained from the Health Insurance Review & Assessment Service of Korea. Cluster, trend, and correlation analyses were performed. Gyeongsangnam-do and Seoul had the highest average number of cases (1,026 and 4,208) and adjusted rate (306 and 424) for clonorchiasis and CCA, respectively. The most likely clusters (MLC) for clonorchiasis and CCA were Busan/Gyeongsangnam-do/Ulsan/Daegu/Gyeongsangbuk-do (Relative Risk; RR=4.55, Likelihood Ratio; LLR=9,131.115) joint cluster and Seoul (RR=2.29, LLR=7,602.472), respectively. The MLC for clonorchiasis was in the southeastern part of Korea, while that for CCA was in the southern part. Clonorchiasis showed a decreasing trend in the southeastern districts, while increased in the southwestern districts. Cities in the central region had a decreasing trend, while the western districts had an increasing trend. In most adults (30-59), infection rate of clonorchiasis showed a significant decrease until 2018, while thereafter increased, although not significant. CCA showed a sharply decreasing tendency. The incidence of clonorchiasis and CCA were positively correlated. In general, the correlation was weak (r=0.39, P<0.001), but it was strongly positive around the 4 river basins (r=0.74, P<0.001). This study might provide an analytic basis for developing an effective system against clonorchiasis and CCA.

• The Korean Journal of Ecology
• /
• v.20 no.2
• /
• pp.125-132
• /
• 1997

A study of forest vegetation in Mt. $T\v{o}kyu$ National Park was investigated by ordination technique. By TWINSPAN(Two-Way Indicator Species Analysis) method, 10 groups were recognized as follows: pinus densiflora, Quercus variabilis, Quercus serrata, Quercus mongolica-Rhododendron schlippenbachii, Quercus mongolica-Abies koreana, Quercus mongolica-Acer pseudo-sieboldi-amum, Quercus mongolica-Symplocos chinensis for. pilosa, Carpinus laxiflora, Fraxinus mandshurica and Taxus cuspidata groups. The floristic composition of these groups showed high correlation to soil moisture(r=0.831), altitude(r=0.784), topography(r=-0.722), organic matter(r=0.642), and pH(r=-0.509) among various environmental factors. According to the results of CCA(Canonical Correspondence Analysis) Pinus densiflora group and Quercus variabilis group were situated in a xeric area at a lower altitude where soil nutrients were poor compared with the other groups. Fraxinus mandshurica group was distributed throughout the valley with high soil moisture and good nutrients, Quercus serrata group and Carpinus laxiflora group were found in the low altitude region with good nutrients, Quercus mongolica group, at the high altitude region with good nutrients, and Quercus mongolica-Acer koreana and Taxus cuspidata at higher altitudes(1, 400-1600 m).

• Journal of the Korean Wood Science and Technology
• /
• v.31 no.6
• /
• pp.55-59
• /
• 2003

The fixation and leaching characteristics of chromated copper arsenate (CCA Type C) and chromium- copper-fluoride-zinc (CCFZ) in domestic softwood (Japanese red pine, Korean pine, and Japanese larch) sapwood were investigated using the expressate method to follow chromium fixation and the American Wood-Preservers' Association (AWPA) leaching procedure to determine leaching properties after fixation. The rates of fixation were affected by preservative types; CCA was fixed much faster than CCFZ for all species evaluated. There were definite differences in the fixation rates of different species, with Korean pine requiring shorter to fix than the other species evaluated. Chromium fixation was greatly enhanced by elevated temperatures, and fixation time can be estimated according to fixation temperatures applied. The percentage of arsenic and zinc leached from domestic softwoods was relatively high compared to chromium and copper, indicating that there is still a relatively high unfixed arsenic and zinc components after complete chromium fixation in CCA-and CCFZ-treated samples, respectively.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.14
• /
• pp.5873-5878
• /
• 2014

Hypoxia and autophagy are known to facilitate tumor progression. We here aimed to investigate the role of hypoxia-associated autophagy in cholangiocarcinoma (CCA) survival and metastasis. Immunostaining of hypoxic-responsive proteins (HIF-$1{\alpha}$ and BNIP3) and a key regulator of autophagy (PI3KC3) were examined in CCA tissues and their expression levels were compared with clinicopathological parameters. A hypoxia mimicking condition ($CoCl_2$ treatment) was also tested regarding CCA cell functions. Our results showed that HIF-$1{\alpha}$ (66%), BNIP3 (44%) and PI3KC3 (46%) showed strong staining in human CCA tissues. Positive expression of HIF-$1{\alpha}$ (p=0.033), BNIP3 (p=0.040) and PI3KC3 (p=0.037) was significantly correlated with lymph node metastasis. HIF-$1{\alpha}$ was well associated with BNIP3 (r=0.3, p<0.01) and PI3KC3 (r=0.2, p<0.01). The survival rates of patients who were positive with HIF-$1{\alpha}$ (p=0.047) or co-expressed HIF-$1{\alpha}$ and BNIP3 (p=0.032) or HIF-$1{\alpha}$ and PI3KC3 (p=0.043) were significantly greater than in the negative groups. CCA cells treated with $CoCl_2$ showed an increase in HIF-$1{\alpha}$, BNIP3, PI3KC3 and LC3-II, with increased cell migration and pFAK levels. These data suggest that hypoxia associated autophagy enhances CCA metastasis, resulting in a poor prognosis of CCA.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.1
• /
• pp.401-406
• /
• 2016

Background: Cholangiocarcinoma is relatively rare worldwide. Most previous reports collected only patients with pathological diagnosis. In fact, however, many patients coming to hospital are diagnosed by clinical suspicion with radiologic imaging and receive treatment without histological confirmation. Real survival data and outcome of each treatment, especially for patients that do not have histologic confirmation, are lacking. In this study, therefore, we aimed to analyze the survival rates of CCA patients and the proportions of patients receiving different treatments. Materials and Methods: A total of 270 patients clinically suspected of CCA and visiting Srinagarind Hospital in May-July 2010, were prospectively followed until December 2014. After checking their clinical records, 163 of 270 patients were finally diagnosed as having CCA, and the data of this group were analyzed for survival rate and received treatments. Results: Of the 163 patients, 96 (58.9%) had intrahepatic, 56 (34.4%) had perihilar and 11 (6.7%) had distal CCA. The majority [107 (65.6%, 95%CI, 57.8-73.0)] received only supportive care. Overall median survival was 4 months (95%CI, 3.3-4.7), and 2-years survival was only 8.1% (95%CI,4.5-12.9). However, the 4 year survival of the R0 resection group was 100%. Conclusions: The present results show that the prognosis of CCA is very poor in North-east Thailand. Most CCA patients receive only treatment to alleviate symptoms due to their advanced stage of disease. Complete surgical resection at the early stage is the only treatment that significantly improves patient survival.