• Macromolecular Research
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• v.16 no.6
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• pp.492-502
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• 2008

This study examined the adsorption of a synthetic cutting fluid and cutting fluid effluent on chitosan and SDS-modified chitosan, Chitosan and SDS-modified chitosan were prepared in form of beads and fibers. A series of batch experiments were carried out as a function of the initial concentration of cutting fluid, contact time and pH of the fluid. The contact angle study suggested that the SDS-modified chitosan was more hydrophobic than chitosan. The Zeta potential study showed that chitosan, SDS-modified chitosan and synthetic cutting fluid had a point of zero charge (PZC) at pH 7.8, 9 and 3.2, respectively. SDS-modified chitosan has a greater adsorption capacity than chitosan. The experimental results show that adsorption capacity of the cutting fluid on 1.0 g of SDS-modified chitosan at pH 3 and for a contact time of 120 min was approximately 2,500 g/kg. The adsorption capacity of chitosan and SDS-modified chitosan increased with decreasing pH. The Langmuir, Freundlich, and Brunauer Emmett and Teller (BET) adsorption models were used to explain the adsorption isotherm. The Langmuir isotherm fitted well with the experimental data of chitosan while the BET isotherm fitted well with the SDS-modified chitosan data. Pseudo first- and second-order kinetic models and intraparticle diffusion model were used to examine the kinetic data. The experimental data was fitted well to a pseudo second-order kinetic model. The significant uptake of cutting fluid on chitosan and SDS-modified chitosan were demonstrated by FT-IR spectroscopy, SEM and heat of combustion.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.232-238
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• 2019

Polyethylenimine-crosslinked chitin (PEI-chitin) was developed as a biosorbent to effectively remove dyestuffs from dye-containing wastewater. A representative reactive dye, Reactive Orange 16 (RO16) was used as a model dye. The effect of pH, isotherm, kinetic and desorption experiments were performed to evaluate the adsorption/desorption ability of PEI-chitin for RO16. As a result, the maximum adsorption capacity calculated by the Langmuir model was 266.3 mg/g at pH 2, and the time needed for adsorption equilibrium was evaluated to be about 20, 60, and 240 min for 50, 100, and 200 mg/L, respectively. The desorption experiments were carried out using various eluents such as ammonia/ethanol mixture, NaOH, $NaHCO_3$, and $Na_2CO_3$, and the highest desorption rate was 75.24% in the ammonia/ethanol mixture.

• Clean Technology
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• v.16 no.3
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• pp.206-212
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• 2010

The adsorption characteristics of quinoline yellow by granular activated carbon were investigated experimently in the batch adsorber and packed column. The adsorptivity of activated carbon for quinoline yellow were largely improved by acidic pH and higher temperature. When the pH was 3 at $60^{\circ}C$, quinoline yellowcould be removed 97 percent of initial concentration(10 mg/L). It was estabilished that the adsorption equilibrium of quinoline yellow on granular activated carbon was successfully fitted by Freundlich isotherm equation in the temperature range from $25^{\circ}C$ to $60^{\circ}C$. The estimated values of k and ${\beta}$ are 38.71~166.60, 0.380~0.490, respectively. The breakthrough curve of activated carbon-packed column depends on the design variables such as initial concentration, bed height, and flow rate.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.26 no.3
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• pp.235-243
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• 2022

Backgrounds/Aims: Historically, the incidence and prognosis of patients diagnosed with intrahepatic cholangiocarcinoma (ICC) have been inadequately understood. Survival analysis in ICC has yet to be investigated in a population-based study. Methods: We conducted a retrospective cohort study using the Surveillance, Epidemiology, and End Results Program (SEER) 18 Registry. Risk ratios were estimated via Poisson regression. Hazard ratios for 5-year survival were estimated using hierarchical Cox regression models. Results: Males show a higher rate of age-adjusted ICC incidence. Blacks carried a decreased risk of ICC diagnosis than Whites, while Asians revealed a higher risk of ICC diagnosis when compared with Whites. The observed survival rates at 12, 36, and 60 months were 36.3%, 12.8%, and 8.1%, respectively. Compared with Whites, Blacks showed an increased risk of death (p < 0.01). Lymph node resection during surgery was associated with a 64.1% reduced risk of mortality (p < 0.01). A higher T stage at diagnosis was associated with poor survival (p < 0.01). Surgery combined with chemoradiotherapy, radiotherapy, or chemotherapy was associated with a reduced risk of mortality compared with nonsurgical interventions (p < 0.01). Conclusions: ICC incidence has been increasing since 2000, especially in White males. The risk of ICC rises with age. Lymph node removal is associated with better survival. In recent years, survival had worsened, and surgical intervention improved survival compared with nonsurgical management.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.70-77
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• 1999

Objective of this research is to obtain fundamental data of carbonized wood wastes for soil condition, de-ordorization, absorption of water, carrier for microbial activity, and purifying agent for water quality of river. The carbonization technique and the properties of carbonized wood wastes(thinned trees) are analyzed. Proximate analysis shows the thinned wood contains 0.22-0.73% ash, 77-80% volatile matter, and 10-14% fixed carbon. The charcoal yield decreases and the shrinkage rate increases as the carbonization temperature and time increase. The charcoal yields of Larix leptolepis, Pinus rigida and Pinus densiflora are high, whereas those of Pinus koraiensis and Quercus variabilis are low. The shrinkage rate by carbonization has same trend as water removal of wood. The specific gravity after the carbonization decreases about 50% comparing to green wood. The charcoal has 0.89-4.08% ash, 6.31-13.79% volatile matter, and 73.9-83.5% fixed carbon. As the carbonization temperature and time increase, pH of charcoal increases. When the carbonization temperature is $400^{\circ}C$, pH is about 7.5. When the temperature is between 600 to $800^{\circ}C$, pH is about 10 with small difference. The water-retention capacity is not affected by the carbonization temperature and time. The water-retention capacity within 24hr is about 2.5 - 3times of sample weight, and the equivalent moisture content becomes 2-10% after 24 hr.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.221-226
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• 2006

Purpose: Controversy still exists over in the prognostic significance of microscopic tumor cell dissemination in patients with cancer. This study evaluated the prognostic implication of isolated tumor cells in the bone marrow of patients with gastric cancer. Materials and Methods: Four hundred nineteen (419) patients who underwent surgery for gastric cancer between June 1998 and July 2000 were enrolled in the study. Bone marrow aspirate was obtained from the iliac crest before removal of the primary tumor. Mononuclear cells were isolated and stained with AE-1/AE-3 PAN-CYTOKERATIN. Results: Cytokeratin-positive cells were found in the bone marrow of 219 patients (52.3%). The incidence varied significantly with the depth of invasion (P=0.021) and the stage (P=0.026). The five-year survival rate of patients with cytokeratin-positive cells was 74.1% and that of patients without cytokeratin-positive cells was 81.1%(P=0.2481). There were no significant differences in the recurrence rate and the site of recurrence according to whether or not cytokeratin-positive cells were present in the bone marrow. Conclusion: The presence of cytokeratin-positive cells in the bone marrow of patients with gastric cancer did not predict outcome and recurrence. Therefore, it cannot be used as a prognostic factor.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.89-95
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• 1997

The current processer of the textile wastewater treatment are mostly consisted of a combination of a physico-chemical and a biological treatment. The overall efficiency of these processes is, however, assessed to be fairly low. It is even worse during the summer season when temperature of the wastewater rises above 40$\circ $C. Therefore, a feasible process of the textile wastewater treatment which can work efficiently at higher temperatures was investigated in this work. We used a bench scale reactor consisted of one 4 liter anaerobic and one 8 liter aerobic tank, and the thermophilic symbiotic PVA degraders, Pasteruella hemolytica KMG1 and Pseudomonas sp. KMG6 that had been isolated in our laboratory. In the preliminary flask experiments, we observed that the thermophilic symbiotic PVA degraders could not grow in the wastewater substrate. Then, we isolated the mutant strains by acclimating the KMG1and KMG6 strains to the wastewater medium. The mutant symbionts (KMG1-1 and KMG6-1) were isolated through 6 times successive transfers into the fresh wastewater medium after 5 days culture for each. The mutant strains obtained grew well in the mixed medium composed of 75% wastewater and 25% synthetic medium, and supplemented with 0.5% PVA as a sole carbon source. During the culture for 14 days at pH 7.0 and 40$\CIRC $C, the bacteria assimilated about 89% of the added PVA. The symbionts degraded equally well all the PVA substrates of different molecular weight (nd=500~30000). In contrast to the flask experiments, in the reactor system the mutant strains showed very low levels of the PVA and COD removal rates. However, the new reactor system with an additional aerobic tank attained 82% removal rate of COD, 94% of PVA degradation and 71% of color index under the conditions of 5% inoculm on the tank 2, incubation temperature of 40$\circ $C, dissolved oxygen level of 2~3 mg/l and retention time of 30 hours. This result ensures that the process described above could be an efficient and feasible treatment for the PVA contained textile wastewater at higher temperatures.

• Environmental Engineering Research
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• v.19 no.1
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• pp.15-22
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• 2014

In this study, the performances of various adsorbents-red mud, zeolite, limestone, and oyster shell-were investigated for the adsorption of multi-metal ions ($Cr^{3+}$, $Ni^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $As^{3+}$, $Cd^{2+}$, and $Pb^{2+}$) from aqueous solutions. The result of scanning electron microscopy analyses indicated that the some metal ions were adsorbed onto the surface of the media. Moreover, Fourier transform infrared spectroscopy analysis showed that the Si(Al)-O bond (red mud and zeolite) and C-O bond (limestone and oyster shell) might be involved in heavy metal adsorption. The changes in the pH of the aqueous solutions upon applying adsorbents were investigated and the adsorption kinetics of the metal ions on different adsorbents were simulated by pseudo-first-order and pseudo-second-order models. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact (except for $As^{3+}$). From the maximum capacity of the adsorption kinetic model, the removal of $Pb^{2+}$ and $Cu^{2+}$ were higher than for the other metal ions. Meanwhile, the reaction rate constants ($k_{1,2}$) indicated the slowest sorption in $As^{3+}$. The adsorption mechanisms of heavy metal ions were not only surface adsorption and ion exchange, but also surface precipitation. Based on the metal ions' adsorption efficiencies, red mud was found to be the most efficient of all the tested adsorbents. In addition, impurities in seawater did not lead to a significant decrease in the adsorption performance. It is concluded that red mud is a more economic high-performance alternative than the other tested adsorption materials for applying a removal of multi-metal in seawater.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.216-225
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• 2018

Over the past 40 years, the public sector has continued to invest in the sewage treatment plants (STPs) in Korea. Currently, the domestic sewage treatment rate is over 90% with the enhancement of operating efficiency of the STPs, and water quality of major rivers has been continuously improved. However, COD and T-N indicators are stagnating or slightly worsening, and though advanced treatment facilities are installed in most of the STPs, there is a limit to the removal of nutrients. Since there are a lot of water pollution sources in the vicinity of the watershed because of high population density in Korea, it is essential to reduce the inflow of the nutrients in order to prevent the eutrophication of the rivers and lakes. While the effluent T-P standard in STPs has greatly strengthened since 2012, which results in the considerable investment for the improvement of treatment process in STPs for the last few years, it is necessary to strengthen the T-N standards, as the effluent standard of T-N has been maintained at 20 mg/L since 2002. In this study, based on the analysis of the effluent T-N standard status of major industrialized countries, and the domestic nitrogen load in public waters, the option of appropriate T-N standard level is reviewed, and the required investment costs and the effect of strengthening the standard are estimated.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.7
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• pp.962-968
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• 2009

The aim of this study was to compare the effects of oviductal fluid, porcine zygote medium (PZM)-3, PZM-4 and PZM-5, and modified PZM-5 culture media, and determine the effects of zona pellucida (ZP) removal on the development of nuclear transfer (NT) embryos. There were no significant differences in the rates of fusion and cleavage among the five different oviductal fluid concentrations. However, the rates of blastocyst formation and the cell numbers per blastocyst were high in the embryos at the 14 and 28 $\mu{g}$/ml concentrations of oviductal fluid compared to the 0, 56 and 100 $\mu{g}$/ml concentrations. The rates of cleavage and blastocyst formation, and the cell numbers per blastocyst were higher in the PZM-3, PZM-5 and modified PZM-5 media than in the PZM-4 medium. However, there were no significant differences in the fusion rates of oocytes among the four culture media. The cell numbers per blastocyst in the embryos without ZP were significantly greater than those with ZP. However, there were no significant differences in the rates of fusion, cleavage and blastocyst formation between the embryos with and without ZP. In conclusion, we improved blastocyst development and the quality of NT embryos by replacing PVA with 3 mg/ml of BSA in PZM-5 medium and supplementing the PZM-5 medium with 14 $\mu{g}$/ml oviductal fluid. The NT embryos produced by the zona-free NT method had a high rate of blastocyst formation in the modified PZM-5 medium.