• 한국세라믹학회지
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• 제56권5호
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• pp.497-505
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• 2019

Lanthanum-based transition metal cations containing perovskites have emerged as potential catalysts for the intermediate-temperature (600-800℃) oxygen reduction reaction (ORR). Here, we report a facile acetylacetone-assisted combustion route for the synthesis of nanostructured La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF6428) cathodes for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). The as-prepared powder was analyzed by thermogravimetry analysis-differential scanning calorimetry. The powder calcined at 800℃ was characterized by X-ray diffraction, scanning electrode microscopy, energy dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller surface area measurements. It was found that the porosity of the air electrode significantly increased by utilizing the nanostructured LSCF6428 instead of commercial powder. The performance of a single cell fabricated with the nanostructured LSCF6428 cathode increased by 112%, from 0.4 to 0.85 W cm^-2, at 700℃. Electrochemical impedance spectroscopy showed a considerable reduction in the area-specific resistance and activation energy from 133.5 to 61.5 kJ/mol, resulting in enhanced electrocatalytic activity toward ORR and overall cell performance.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.268-279
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• 2023

The pharmaceutical industry in Bangladesh produces a diverse range of antibiotics for human and animal use, however, waste disposal management is inadequate. This results in substantial quantities of antibiotics being discharged into water bodies, which provide suitable environment for the growth of antibiotic-resistant bacteria, capable of spreading resistance genes. This study intended for exploring the bacterial antibiotic resistance profile in adjoining aquatic environmental sources of pharmaceutical manufacturing facilities in Bangladesh. Seven surface water samples were collected from the vicinity of two pharmaceutical industries located in the Savar area and 51 Escherichia coli isolates were identified using both phenotypic and genotypic methods. Antibiotic susceptibility tests revealed the highest percentage of resistance against ampicillin, azithromycin, and nalidixic acid (100%) and the lowest resistance against meropenem (1.96%) out of sixteen different antibiotics tested. 100% of the study E. coli isolates were observed with Multidrug resistance phenotypes, with the Multiple Antibiotic Resistance (MAR) value ranging from 0.6-1.0. Furthermore, 69% of the isolates were Extended Spectrum Beta-Lactamases (ESBL) positive as per the Double Disk Diffusion Synergy Test (DDST). ESBL resistance genes bla_TEM, bla_CTX-M-13, bla_CTX-M-15, and bla_SHV were detected in 70.6% (n = 36), 60.8% (n = 32), 54.9% (n = 28), and 1.96% (n = 1) of the isolates, respectively, by Polymerase Chain Reaction (PCR). Additionally, 15.68% (n = 8) of the isolates were positive for E. coli specific virulence genes in PCR. These findings suggest that pharmaceutical wastewater, if not properly treated, could be a formidable source of antibiotic resistance spread in the surrounding aquatic environment. Therefore, continued surveillance for drug resistance among bacterial populations around drug manufacturing facilities in Bangladesh is necessary, along with proper waste disposal management.

• Korean Chemical Engineering Research
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• 제49권1호
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• pp.10-14
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• 2011

철 이온 교환방법에 의해 메조기공을 갖는 활성탄소 섬유(ACF)를 제조하고, 이를 사용하여 전기 이중층 커패시터(EDLC)의 전극소재 성능을 조사하였다. 질산처리에 의해 제조된 메조기공 ACF는 비표면적이 1,249, 664 $m^2/g$이고, 메조 기공 분율이 70.6-81.3%이고, 평균 기공크기는 약 2.78~4.14 nm이다. 질산처리시간이 짧을수록 비표면적이 크고 메조 기공이 적게 발달됨을 알 수 있었다. 전기이중층 커패시터의 성능을 조사하기 위해서, 메조기공 ACF, 도전제, 바인더를 사용하여 단위 셀을 제조하였으며, 유기 전해질을 사용하였다. 2시간 질산으로 처리된 ACF의 비 축전양은 0.47 $F/cm^2$이고, 20회 충.방전 테스트에서 안정된 실험결과를 얻을 수 있었다. EDLC의 전기화학적 성능은 ACF 전극의 비표면적에 크게 영향을 받으며 메조기공은 전하의 확산저항을 감소시키는 것을 알 수 있었다.

• Nutrition Research and Practice
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• 제4권4호
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• pp.259-269
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• 2010

Resistance training (RT) is associated with reduced risk of low grade inflammation related diseases, such as cardiovascular disease and type 2 diabetes. The majority of the data studying cytokines and exercise comes from endurance exercise. In contrast, evidence establishing a relationship between RT and inflammation is more limited. This review focuses on the cytokine responses both following an acute bout, and after chronic RT. In addition, the effect of RT on low grade systemic inflammation such as individuals at risk for type 2 diabetes is reviewed. Cytokines are secreted proteins that influence the survival, proliferation, and differentiation of immune cells and other organ systems. Cytokines function as intracellular signals and almost all cells in the body either secrete them or have cytokine receptors. Thus, understanding cytokine role in a specific physiological situation such as a bout of RT can be exceedingly complex. The overall effect of long term RT appears to ameliorate inflammation, but the specific effects on the inflammatory cytokine, tumor necrosis factor alpha are not clear, requiring further research. Furthermore, it is critical to differentiate between chronically and acute Interleukin-6 levels and its sources. The intensity of the RT and the characteristics of the training protocol may exert singular cytokine responses and as a result different adaptations to exercise. More research is needed in the area of RT in healthy populations, specifically sorting out gender and age RT acute responses. More importantly, studies are needed in obese individuals who are at high risk of developing low grade systemic inflammatory related diseases. Assuring adherence to the RT program is essential to get the benefits after overcoming the first acute RT responses. Hence RT could be an effective way to prevent, and delay low grade systemic inflammatory related diseases.

• Geomechanics and Engineering
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• 제12권3호
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• pp.399-415
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• 2017

A series of direct shear tests were conducted to investigate the frictional properties of the interface between structures and the filling soil of Chongqing airport fourth stage expansion project. Two types of structures are investigated, one is low carbon steel and the other is the bedrock sampled from the site. The influence of soil water content, surface roughness and material types of structure were analyzed. The tests show that the interface friction and shear displacement curve has no softening stage and the curve shape is close to the Clough-Duncan hyperbola, while the soil is mainly shear contraction during testing. The interface frictional resistance and normal stress curve meets the Mohr-Coulomb criterion and the derived friction angle and frictional resistance of interface increase as surface roughness increases but is always lower than the internal friction angle and shear strength of soil respectively. When surface roughness is much larger than soil grain size, soil-structure interface is nearly shear surface in soil. In addition to the geometry of structural surface, the material types of structure also affects the performance of soil-structure interface. The wet interface frictional resistance will become lower than the natural one under specific conditions.

• 한국세라믹학회지
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• 제42권12호
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• pp.833-841
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• 2005

The oxidation resistance and electrical conductivity of various commercial ferritic stainless steels including STS444 were tested in an air atmosphere at $700^{\circ}C$. Crofer22 developed specially for SOFC interconnect was also examined for the aim of comparing with the test results of STS444. Although STS444 exhibited higher oxidation resistance than Corfer22, the electrical conductivity of the scale formed on Crofer22 was higher, indicating that the resistivity of scale formed on Crofer22 is much lower than that of STS444. To gain a better understanding of the relation between oxidation behavior and electrical conductivity, the oxide scales formed on STS444 and Crofer22 were analyzed in terms of the structure, composition, and phase. Consequently, the influence of alloying elements on electrical conductivity of Fe-Cr alloys was discussed.

• BMB Reports
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• 제56권6호
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• pp.347-352
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• 2023

The protein family of poly (ADP-ribose) polymerases (PARPs) is comprised of multifunctional nuclear enzymes. Several PARP inhibitors have been developed as new anticancer drugs to combat resistance to chemotherapy. Herein, we characterized PARP4 mRNA expression profiles in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. PARP4 mRNA expression was significantly upregulated in cisplatin-resistant ovarian cancer cell lines, and this upregulation was associated with the hypomethylation of specific cytosine-phosphate-guanine (CpG) sites (cg18582260 and cg17117459) on its promoter. Reduced PARP4 expression was restored by treating cisplatin-sensitive cell lines with a demethylation agent, implicating the epigenetic regulation of PARP4 expression by promoter methylation. Depletion of PARP4 expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance and promoted cisplatin-induced DNA fragmentation. The differential mRNA expression and DNA methylation status at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) according to cisplatin responses, was further validated in primary ovarian tumor tissues. The results showed significantly increased PARP4 mRNA expressions and decreased DNA methylation levels at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) in cisplatin-resistant patients. Additionally, the DNA methylation status at cg18582260 CpG sites in ovarian tumor tissues showed fairly clear discrimination between cisplatin-resistant patients and cisplatin-sensitive patients, with high accuracy (area under the curve = 0.86, P = 0.003845). Our findings suggest that the DNA methylation status of PARP4 at the specific promoter site (cg18582260) may be a useful diagnostic biomarker for predicting the response to cisplatin in ovarian cancer patients.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1593-1595
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• 1999

Effects of carbon black species and concentration on the mechanical and electrical properties of alumina trihydrate filled EPDM compounds were investigated. Mechanical properties improved with increasing carbon black concentration, and these effects were prominent in carbon blacks haying large specific area. In the case of non-conductive carbon black. tracking resistance improved when a small amount of carbon black was added to EPDM. Conductive carbon black showed detrimental effect to dielectric losses, volume resistivity and tracking resistance of EPDM compound.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.364-367
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• 2006

The decrease of polarization resistance in cathode is the key point for intermediate temperature SOFC(Solid Oxide Fuel Cell). In this study, the Influence of Co substitution in B-site at perovskite PSCM (Pr0.3Sr0.7CoxMn(1-x)) was investigated. The PSCM series exhibits excellent MIEC(Mixed ionic Electronic Conductor) properties. The ASR(Area Specific Resistance) of PSCM3773 was $0.174{\Omega}cm^2\;at\;700^{\circ}C$. The activation energy of PSCM3773 was also lower than other compositions of PSCM. The ASR values were increased gradually during the thermal cycling test of PSCM37773 due to the delamination between electrolyte and cathode materials.

• Computers and Concrete
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• 제2권5호
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• pp.381-388
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• 2005

This paper presents the results of a study on binary blends of Portland cement and fly ash with complex admixture used for the concrete structures to meet specific performance objectives in east coastal area of China. The concretes were evaluated for workability, strength, water permeability, drying shrinkage, sulfate resistance and electrical resistance. Environmental Scanning Electron Microscopy (ESEM) was used to examine the microstructure of concrete made by complex admixture compared with control batches without complex admixture. The combined efforts of fly ash and complex admixture led to an improvement in the workability, strength and durability.