• Environmental Engineering Research
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• v.23 no.3
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• pp.301-308
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• 2018

We investigated simultaneous removal of heavy metals such as Cr, Ni, and Zn by adsorption onto powdered activated carbon (PAC) and PAC modified with sodium diethyldithiocarbamate (PAC-SDDC). Modification of PAC was confirmed by Fourier transform infrared spectroscopy and Scanning electron microscopy and energy dispersive X-ray spectroscopy. Both PAC and PAC-SDDC reached adsorption equilibrium within 48 h, and the adsorption kinetics followed a pseudo-second order reaction kinetics. The removal of metals was enhanced with increasing both adsorbent dosage and followed the descending order of Cr > Ni > Zn for PAC and Cr > Zn > Ni for PAC-SDDC, respectively. Adsorption kinetics followed pseudo-second order kinetics. Adsorption kinetic results were well fitted by the Freundlich isotherm except for Cr adsorption onto PAC. The optimum pH for heavy metal adsorption onto PAC was 5, whereas that for PAC-SDDC ranged from 7 to 9, indicating that modification of PAC with SDDC significantly enhanced heavy metal adsorption, especially under neutral and alkaline pH conditions. Our results imply that SDDC modified PAC can be applied to effectively remove heavy metals especially Cr in plating wastewaters without adjusting pH from alkaline to neutral.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.3
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• pp.143-150
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• 2023

Background: The successful production of superior or transgenic offspring from in vitro produced embryos in cattle relies heavily on the quality of blastocyst stage embryos. In order to enhance the developmental competency of these embryos, a novel culture method was devised. Methods: This study utilized stem cell culture medium (SCM) from hESCs as a supplement within the culture medium for bovine in vitro produced embryos. To gauge the efficacy of this approach, in vitro fertilized embryos were subjected to culture in CR1aa medium enriched with one of three supplements: 0.3% BSA, 10% FBS, or 10% SCM. Results: The blastocyst development and hatching rates of one-cell zygotes cultured in CR1aa medium supplemented with SCM (23.9% and 10.2%) surpassed those cultured in CR1aa medium supplemented with BSA (9.3% and 0.0%) or FBS (3.1% and 0.0%) (p < 0.05). Furthermore, post-zygotic gene activation, cleaved embryos cultured in CR1aa medium supplemented with SCM (57.8% and 34.5%) exhibited notably higher rates (p < 0.05) compared to those cultured with BSA (12.9% and 0.0%) or FBS (45.7% and 22.5%) supplementation. Furthermore, the microinjection of SCM into the cytoplasm or pronucleus of fertilized zygotes resulted in elevated blastocyst development and hatching rates, particularly when the microinjected embryos were subsequently cultured in CR1aa medium supplemented with SCM from the 8-cell embryo stage onwards (p < 0.05), in contrast to those cultured with FBS supplementation. Conclusions: In conclusion, this study conclusively demonstrated that the incorporation of SCM into the culture medium significantly enhances the developmental progress of preimplantation embryos.

• Korean Journal of Radiology
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• v.24 no.9
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• pp.890-902
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• 2023

Objective: The clinical impact of artificial intelligence-based computer-aided detection (AI-CAD) beyond diagnostic accuracy remains uncertain. We aimed to investigate the influence of the clinical implementation of AI-CAD for chest radiograph (CR) interpretation in daily practice on the rate of referral for chest computed tomography (CT). Materials and Methods: AI-CAD was implemented in clinical practice at the Seoul National University Hospital. CRs obtained from patients who visited the pulmonology outpatient clinics before (January-December 2019) and after (January-December 2020) implementation were included in this study. After implementation, the referring pulmonologist requested CRs with or without AI-CAD analysis. We conducted multivariable logistic regression analyses to evaluate the associations between using AI-CAD and the following study outcomes: the rate of chest CT referral, defined as request and actual acquisition of chest CT within 30 days after CR acquisition, and the CT referral rates separately for subsequent positive and negative CT results. Multivariable analyses included various covariates such as patient age and sex, time of CR acquisition (before versus after AI-CAD implementation), referring pulmonologist, nature of the CR examination (baseline versus follow-up examination), and radiology reports presence at the time of the pulmonology visit. Results: A total of 28546 CRs from 14565 patients (mean age: 67 years; 7130 males) and 25888 CRs from 12929 patients (mean age: 67 years; 6435 males) before and after AI-CAD implementation were included. The use of AI-CAD was independently associated with increased chest CT referrals (odds ratio [OR], 1.33; P = 0.008) and referrals with subsequent negative chest CT results (OR, 1.46; P = 0.005). Meanwhile, referrals with positive chest CT results were not significantly associated with AI-CAD use (OR, 1.08; P = 0.647). Conclusion: The use of AI-CAD for CR interpretation in pulmonology outpatients was independently associated with an increased frequency of overall referrals for chest CT scans and referrals with subsequent negative results.

• Journal of Powder Materials
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• v.21 no.4
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• pp.294-300
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• 2014

The connecting rod is one of the most important parts in automotive engines, transforming the reciprocal motion of a piston generated by internal combustion into the rotational motion of a crankshaft. Recent advances in high performance automobile engines demand corresponding technological breakthroughs in the materials for engine parts. In the present research, the powder metallurgy (P/M) process was used to replace conventional quenching and/or tempering processes for mass production and ultimately for more cost-efficient manufacturing of high strength connecting rods. The development of P/M alloy powder was undertaken not only to achieve the improvement in mechanical properties, but also to enhance the machinability of the P/M processed connecting rods. Specifically $MoS_2$ powders were added as lubricants to non-normalizing Fe-Cr-Mn-V-C alloy powder to improve the post-sintering machinability. The effects of $MoS_2$ addition on the microstructure, mechanical properties, and machining characteristics were investigated.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.497-502
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• 1999

Removal of Pb(Ⅱ), Cu(Ⅱ), Cr(Ⅲ), and Zn(Ⅱ) ions from aqueous solutions using the adsorption process on domestic loess minerals has been investigated. Variations of contact time, pH, adsorption isotherms and selectivity of coexisting ions and leachate were experimental parameters. YDI, YPT and KRT samples diluted in 1% aquous solution which was adjusted pH 10.8, 8.0 and 6.50, respectively. The result of XRD measurement, Quartz was mainly observed in all samples. In the case of KRT sample, Kaolinite, Feldspar, Chlorite consisting of clay minerals shows almost same pattern with YPT samples. Different properties showed from the YDI sample containing Iillite, remarkably. For all the metals, maximum adsorption was observed at 30min∼60min. Adsorption of metal ions on loess minerals were reached an equilibrium by shaking the solution for about 30min. Removal efficiency of Pb(Ⅱ) ion for KRT, YPT and YDI were 84.7%, 92% and 100%, respectively. The Cu(Ⅱ) and Zn(Ⅱ) adsorptivity on KRT showed the low in various pH solution However, those on YPT and YDI were high than 90% except for the pH 2 solution. The orders of adsorptivities for domestic loess minerals showed as following : YPT>KRT>YDI. The adsorption isotherms of Cu(Ⅱ) and Zn(Ⅱ) ions on clay minerals were fitted to a Freundlich's. Freundlich constants(1/n) of KRT and YPT domestic loess minerals were 0.63, 0.97 and 0.36, 0.25, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.9039-9043
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• 2014

There is a continuing need for innovative alternative therapies for liver cancer. DNA vaccines for hormone/growth factor immune deprivation represent a feasible and attractive approach for cancer treatment. We reported a preventive effect of a DNA vaccine based on six copies of the B cell epitope GRP18-27 with optimized adjuvants against H22 hepatocarcinoma. Vaccination with pCR3.1-VS-HSP65-TP-GRP6-M2 (vaccine) elicited much higher level of anti-GRP antibodies and proved efficacious in preventing growth of transplanted hepatocarcinoma cells. The tumor size and weight were significantly lower (p<0.05) in the vaccine subgroup than in the control pCR3.1-VS-TP-HSP65-TP-GRP6, pCR3.1-VS-TP-HSP65-TP-M2 or saline subgroups. In addition, significant reduction of tumor-induced angiogenesis associated with intradermal tumors of H22 cells was observed. These potent effects may open ways towards the development of new immunotherapeutic approaches in the treatment of liver cancer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.909-912
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• 2001

Lanthanide orthochromite materials have been widely studied as refractory conducting ceramics because of their electrical conductivity, oxidation resistance and high melting points. In this paper theoretical and experimental analysis about electric conductivity of the SHS prepared ceramics was carried out. The usefulness of the Seebeck-coefficient measurements as a function of P(O$_2$) is emphasized. Electronic conduction was found to be n-type in the lower P(O$_2$) range, and p-type in the higher P(O$_2$) range. The carrier concentrations were calculated as a function of P(O$_2$) and defect structure.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1279-1281
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• 1998

The Co-Cr thin films are one of the most suitable candidates for perpendicular magnetic recording media. The facing targets sputtering(FTS) method has a advantage of preparing films over a wide range of working gas pressure on plasma-free substrates. In this study, we investigated the possibility of employing FTS system for depositing Co-Cr films, Co-Cr thin films were deposited with continuously sputter gas pressure ($P_{Ar}$ = 0.1 mTorr) by FTS method at temperature of $40^{\circ}C$. We find that the change of thickness and deposition rate of sputtered Co-Cr thin films affect crystal orientation and magnetic properties. Crystallographic and magnetic properties were evaluated by x-ray diffractometry(XRD) and vibrating sample magnetometer(VSM) respectively. It has been confirmed that the FTS method is very useful for preparing Co-Cr thin film recording media.

• Korean Journal of Metals and Materials
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• v.50 no.5
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• pp.361-368
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• 2012

Fe-(10, 20, 30, 40) wt%Cr alloys were corroded in $Na_2SO_4$ salts ($m.p.=884^{\circ}C$) at $800{\sim}900^{\circ}C$ for 3-300 hrs. Their corrosion resistance increased with an increase in Cr content owing to the formation of slowly growing $Cr_2O_3$. During corrosion, $Na_2SO_4$ dissociated and reacted with the alloys to form $Cr_2O_3$ and $Fe_2O_3$. Since $Fe_2O_3$ dissolved fast into the salts, most of the scales consisted primarily of $Cr_2O_3$. Inside the scale, a small amount of sulfides also existed. The oxidation, dissolution and detachment of the formed scales occurred significantly.

• Animal Bioscience
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• v.36 no.8
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• pp.1151-1155
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• 2023

Objective: This study analyzes interactions of body condition score (BCS) with other factors and the effect of BCS on estimates of genetic paremeters of conception rate (CR) in Japanese Black cows. Methods: Factors affecting CR were analyzed through the linear mixed model, and genetic parameters of CR were estimated through the threshold animal model. Results: The interactions between BCS and each season and the number of artificial inseminations (AI) was significant (p<0.05), but that between BCS and parity showed no significance for CR. High CR was observed with BCS 3 in autumn (0.56±0.01) and BCS 4 in summer (0.56±0.02). The highest CR with BCS 3 (0.56±0.02) and BCS 4 (0.55±0.01) was observed at first AI. With BCS 5, however, the highest CR (0.55±0.08) was observed at second AI. Conclusion: The model with BCS was notably conducive to the estimation of genetic parameters because of a low deviance information criterion of heritability that, nevertheless, was slightly lower than the model without BCS.