Hydrogen peroxide (H2O2) is widely used in bleaching treatments in the pulp and paper industry, in wastewater treatment, and as a food additive. However, H2O2 solutions are unstable and decompose slowly when subjected to external factors such as light, high temperatures, or metal compounds. Therefore, a simple and reliable method to measure the concentration of H2O2 is required for its proper use in various applications. We determined the concentration of an H2O2 solution by measurement at a single wavelength (249 nm) without any reagents or complex analytical procedures. In the present work, the measurable concentration of H2O2 was as low as 0.015 wt% (4.41 mM) and as high as 0.300 wt% (88.2 mM), with high linearity (99.99% at 249 nm) between the concentration of H2O2 and the optical density (OD) values. In addition, the method could be used to measure the concentration of H2O2 in a peracetic acid solution without interference from acetic acid and peracetate ion.

Background: Single nucleotide polymorphisms (SNPs) are widely used genetic markers with applications in human disease diagnostics, animal breeding, and evolutionary studies, but existing genotyping methods can be labor-intensive and costly. The aim of this study is to develop a simple and rapid method for identification of a single nucleotide change. Methods: A modified Polymerase Chain Reaction Amplification of Multiple Specific Alleles (PAMSA) and high resolution melt (HRM) analysis was performed to discriminate a bovine polymorphism in the NCAPG gene (rs109570900, 1326T > G). Results: The inclusion of tails in the primers enabled allele discrimination based on PCR product lengths, detected through agarose gel electrophoresis, successfully determining various genotypes, albeit with some time and labor intensity due to the use of relatively costly high-resolution agarose gels. Additionally, high-resolution melt (HRM) analysis with tailed primers effectively distinguished the GG genotype from the TT genotype in bovine muscle cell lines, offering a reliable way to distinguish SNP polymorphisms without the need for time-consuming AS-PCR. Conclusions: Our experiments demonstrated the importance of incorporating unique mismatched bases in the allele-specific primers to prevent cross-amplification by fragmented primers. This efficient and cost-effective method, as presented here, enables genotyping laboratories to analyze SNPs using standard real-time PCR.

For practical applications of graphene sheets in a variety of fields, mass production of high-quality graphene sheets is necessary. Herein, we reported a cost-effective, green, and simple approach to synthesizing mass production exfoliated graphene (EG) flakes employing electrochemical exfoliation of pencil graphite in neutral aqueous electrolytes. Pencil graphite cores of different grades were applied as anode and cathode electrodes and exposed to the electrolyte solution at a different voltage. Several parameters were examined and optimized, including pencil grade (2,4,6,8 B), applied voltage (10, 15, 20, 30 V), different inorganic electrolytes ((NH4)2SO4, Na2SO4, NaNO3, NaCl, and CH3COONa), and the concentration of electrolytes. The optimal condition was chosen by considering the mass of produced graphene and the conductivity of the graphene solution. The optimal conditions were as follow: pencil grade: 6B; applied voltage: 10 V; electrolyte type: Na2SO4; electrolyte concentration: 0.1 M. Under these conditions, the production yield was > 95% within 3 h and 9 min. The EG was characterized by utilizing FT-IR, XRD, Raman spectroscopy, FE-SEM, Cyclic Voltammetry, and Electrochemical Impedance Spectroscopy (EIS). Characterization indicates that the synthesized EG had an XRD peak at 2θ = 26.6° and an ID/ IG ratio of 0.36. Furthermore, the EG showed good conductivity when tested by cyclic voltammetry and EIS whereas the R2 values were 985.8 and 76.3 Ω for bare GCE and EG/GCE, respectively. In addition, EG effectively removed cadmium (Cd(II)) with an adsorption level of 8.72 mg/g. The results from this study suggest that EG can be scaled up and commercialized in an environmentally friendly and low-cost manner, especially in low-income countries, and using it to rectify metal ions.

Copper nanoparticles (CuNPs) are considered of great importance due to their high catalytic and antimicrobial activities. This study focuses on the preparation and characterization of CuNPs, and on their antibacterial/antifungal activities. A copper salt (copper sulfate pentahydrate) as precursor, starch as stabilizing agent, and ascorbic acid as reducing agent were used to fabricate CuNPs. The resulting product was characterized via different techniques such as X-ray diffractrometry (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning electron microscopy (SEM) to confirm its characteristic properties. Employing the Scherrer formula, the mean crystallite sizes of copper (Cu) and cuprous oxide (Cu2O) nanocrystals were found to be 29.21 and 25.33 nm, respectively, as measured from the main X-ray diffraction peaks. The functional groups present in the resulting CuNPs were confirmed by FTIR. In addition, the engineered CuNPs showed antibacterial and antifungal activity against tested pathogenic bacterial and fungal strains.

본 논문에서는 압입시험을 통해서 초탄성 재료 물성치를 평가하는 간단한 방법을 제시하였다. 초탄성 재료 모델 중, 3개의 물성치(C10, C20, C30)를 가지는 Yeoh 모델을 선택하여 주연신률로 표현되는 변형률 에너지 밀도를 적용하였다. Yeoh 물성치를 변화시키며, 구형 압입시험 유한요소해석을 수행하여 압입자 반력-변위 곡선을 획득하였다. 압입자 반력-변위 곡선을 3차 다항식으로 근사하였고, 이 다항식을 물성치(C10, C20, C30)의 3차 곱으로 근사된 3차 다항식으로 표현하였다. 압입자 반력-변위 곡선 근사를 위해 회귀분석을 진행하여 수식들의 계수를 결정하였으며, 이 회귀식을 이용하여 초탄성 재료의 물성치를 평가 하였다. 초탄성 재료 물성치 평가를 수행하고 오차를 비교하여 유효성을 보여 주었다.

Among the 8,700 in-service bridges in national highway, the steel bridges cover the 1600 sites and make up approximately the 20 percentage of the total amounts. Due to recent rapid increase both in traffic volume and in frequency of overloaded vehicles, the need for re-evaluating the fatigue life of the steel bridges is increasing. However, the existing fatigue life assessment method are too complicate and difficult to apply to field directly. To improve such deficiency of the existing fatigue life assessment procedures, this study reviews the fatigue life assessment methods in Eurocode and then proposes an easier and simpler fatigue life assessment procedure that could evaluate the remaining fatigue life of the steel bridges using traffic data collected from a high-speed weigh-in-motion system installed in the national highway network. The Proposed fatigue life evaluation method is as follows; 1. Calculation of fatigue resistance 𝛾𝑀f and fatigue strength Δ𝜎𝑐 used in design, 2. Calculation of partial safety factor 𝛾𝐹f for equivalent stress range, 3. Calculation of stress range Δ𝜎𝐸2 using influence line, 4. Calculation of damage equivalent factor λ, 5. Review of Fatigue state and evaluation of fatigue life. The Proposed method can omit the existing complicated and repetitive calculation. Therefore, proposed method can estimate the fatigue damage and the theoretical fatigue life simply by comparing with the existing method.

The recent increase in truck traffic volume and overloading frequency causes a growing need to re-evaluation of fatigue life of steel bridges. However, the traditional fatigue analysis method, that is cumulative damage method(CDM), has limitation to apply to a number of bridges because the required calculation steps are very cumbersome and complicated. This study investigates the feasibility and applicability of proposed simple fatigue evaluation method based on the equivalent damage method (EDM) in Eurocode to estimate the remaining fatigue life for a highway bridge. The Proposed fatigue life evaluation method is as follows; 1. Calculation of fatigue resistance 𝛾𝑀f and fatigue strength Δ𝜎𝑐 used in design, 2. Calculation of partial safety factor 𝛾𝐹f for equivalent stress range, 3. Calculation of stress range Δ𝜎𝐸2 using influence line, 4. Calculation of damage equivalent factor λ, 5. Review of Fatigue state and evaluation of fatigue life. The specifications of the target bridge are as follows; Location : Gyeongbu Expressway, Design Life : 100yr, Construction year : 2006, Total length : 341m, Type of superstructure : continuous steel box girder. The resulting remaining fatigue life estimated by both EDM and CDM have been compared. Remaining fatigue life of target bridge in 2016 was calculated 365yr(EDM using WIM data in 2014), 334yr(CDM using strain gauge data in 2012 and reflecting 2% annual traffic volume increase, Gil and Kang(2012)). As a result of comparison, The remaining fatigue life using proposed method(EDM) was evaluated about 10% higher than the CDM. This result, because traffic volume increase had not reflected when calculation of remaining fatigue life using EDM. Proposed method(EDM) can evaluate remaining fatigue life more easily and simply than CDM.

Almost all buildings and infrastructures made of advanced composite materials are fabricated without proper design. Unlike airplanes or automobiles, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long span bridges. People try to build 100-story buildings or several thousand meter long span bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design. Simple method of analysis, Folded plate theory, Size effects in failure, and Critical natural frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method. In this paper, folded plate theory are presented for practicing engineers.

The white button mushroom, Agaricus bisporus, is commercially the fifth most important edible mushroom, accounting for the production of 9,732 tons of mushrooms in Korea in 2015. The genus Agaricus has been known for its potential to degrade lignocellulosic materials. Chemical analyses carried out during the cultivation of A. bisporus indicated that the cellulose, hemicellulose, and lignin fractions were changed preferentially for both vegetative growth and sexual reproduction. We screened A. bisporus strains for effective biodegradation through extracellular enzyme activity using cellulase, xylanase, and ligninolytic enzymes. The enzyme biodegradations were conducted as follows: mycelia of collected strains were incubated in 0.5% CMC-MMP (malt-mops-peptone), 0.5 Xylan-MMP, and 0.5% lignin-MMP media for 14 days. Incubated mycelia were stained with 0.2% trypan blue. Eighteen strains were divided into 8 groups based on different extracellular enzyme activity in MMP media. These strains were then incubated in sterilized compost and compost media for 20 days to identify correlations between mycelial growth in compost media and extracellular enzyme activity. In this study, the coefficient of determination was the highest between mycelial growth in compost media and ligninolytic enzyme activity. It is suggested that comparison with ligninolytic enzyme activity of the tested strains is a simple method of screening for rapid mycelial growth in compost to select good mother strains for the breeding of A. bisporus.

To prepare Mn4+-activated K2TiF6 phosphor, a precipitation method without using hydrofluoric acid (HF) was designed. In the synthetic reaction, to prevent the decomposition of K2MnF6, which is used as a source of Mn4+ activator, NH5F2 solution was adopted in place of the HF solution. Single phase K2TiF6:Mn4+ phosphors were successfully synthesized through the designed reaction at room temperature. To acquire high luminance of the phosphor, the reaction conditions such as the type and concentration of the reactants were optimized. Also, the optimum content of Mn4+ activator was evaluator based on the emission intensity. Photoluminescence properties such as excitation and emission spectrum, decay curve, and temperature dependence of PL intensity were investigated. In order to examine the applicability of this material to a white LED, the electroluminescence property of a pc-WLED fabricated by combining the K2TiF6:Mn4+ phosphor with a 450 nm blue-LED chip was measured.

This study was carried out to study the survival rate of thawed Hanwoo embryos frozen by the slow-rate freezing or the cryotop vitrification method. Hanwoo cumulus-oocyte complexes were recovered from ovaries at a slaughter house, matured for 20~22 hours, fertilized with Hanwoo semen for 5~6 hours, and cultured for 7~9 days in 38.5℃, 5% CO2 incubator. For freezing, Day 7∼9 blastocysts were collected. Embryos for the slow-rate freezing were equilibrated in 1.8 M ethylene glycol (EG) with Dulbecco's phosphate-buffered saline (D-PBS). Programmable cell freezer was precooled down to —7℃, and the straw was seeded during 8 minutes-holding time, and was cooled to —35℃ at the cooling rate of 0.3℃/min, and then was plunged and stored in liquid nitrogen. Embryos for the cryotop vitrification were treated in TCM199 with 0.5 M sucrose, 16% EG, 16% dimethylsulfoxide (DMSO). Embryos were then loaded individually onto cryotop and plunged directly into liquid nitrogen. The survival rates of embryos frozen by these two freezing methods were evaluated at 12 to 24h post-thawing. The survival rates of frozen/thawed Hanwoo embryos by the cryotop vitrification method (56.86 ± 26.53%) were slightly higher than those by the slow-rate freezing method (55.07 ± 26.43%) with no significant difference. Using the cryotop vitrification and the slow-rate freezing of Hanwoo blastocysts on Day 7 following in-vitro fertilization (IVF) treatment, the survival rates of frozen/thawed Hanwoo embryos were 72.65 ± 18.3% and 79.06 ± 17.8%, respectively. The survival rates by the cryotop vitrification were higher than those by the slow-rate freezing on both Day 8 and 9 with significantly higher survival rate on Day 9 (p<0.05). Using the cryotop vitrification and the slow-rate freezing of Hanwoo embryos to compare between three different blastocyst stages, the survival rates of the blastocyst stage embryos were 66.22 ± 18.8% and 45.76 ± 12.8%, respectively with higher survival rate by the vitrification method (p<0.05). And the survival rate of expanded blastocysts was higher than those of early blastocysts and blastocysts in two freezing methods with significantly higher survival rate by the slow-rate freezing method (p<0.05).

Almost all buildings and infrastructures made of advanced composite materials are fabricated without proper design. Unlike airplanes or automobiles, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long span bridges. People try to build 100-story buildings or several thousand meter long span bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design. Concept optimization, Simple method of analysis, Folded plate theory, Size effects in failure, and Critical natural frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method. In this paper, concept optimization and folded plate theory are presented for practicing engineers.

사과는 전 세계적으로 대표적 과수의 하나로서 우량 사과의 생산을 위하여 신속하고 경제적이며 정확한 사과바이러스 진단이 요구되고 있다. RT-PCR은 사과바이러스 진단을 위한 중요한 기술로 서 우선 시료조직의 분쇄 및 균질화를 통한 양질의 RNA 추출이 필수적이다. 그러나 분쇄작업은 다 량의 시료의 경우 많은 시간과 노동이 요구된다. 본 연구에서는 조직 분쇄과정이 없이 단순 가열에 의한 RNA 추출을 시도하였으며 줄기조직이 잎조직보다 약간 더 적합함을 보여주었다. 그러나 RT-PCR에 의한 사과바이러스 진단에서는 모두 동일한 결과를 나타냈다. 이로써 사과 조직에 대한 단순가열로써 매우 간편하게 양질의 RNA추출이 가능함을 제시하였다.

단순지지된 슬래브교량의 경우 특별직교이방성 판이론에 의하여 해석하였다. 이 방법은 일반 기술자들에게는 너무 어려워서 현장에서 기술자들이 실무적으로 접근하기에는 많은 어려움이 있다. 본 연구에서는 일반 현장의 실무 기 술자들이 사용할 수 있는 보 이론을 사용하여 단순지지된 콘크리트 슬래브를 단위 폭을 가진 보로 해석이 가능하도 록 수정계수를 만들어서 실무에 적용할 때의 사용 가능한 자료를 만들고자 하였다. 본 연구에서는 1 : 1 ～ 1 : 6 까 지 형상비를 변화 시켜가며 해석을 수행하였다. 본 논문의 연구의 결과는 단순지지된 슬래브교량의 해석에 이용할 수 있다.

Bone marrow (BM) cell harvesting is a crucial element in the isolation of mesenchymal stem cells (MSCs). A simple method for harvesting cat BM cells is described. The results show that a large number of BM cells can rapidly be harvested from the cat by this simple procedure. MSCs prepared by density-gradient method were spindle-shaped morphology with bipolar or polygonal cell bodies and strongly positive for CD9 and CD44 and negative for CD18 and CD45-like. They were capable of differentiation to adipocytic and osteocytic phenotypes when exposed to appropriate induction media. The advantages of this method are its rapidity, simplicity, low invasiveness, and low donor attrition and good outcome.

본 논문에서는 중고주파수 영역에서 진동하는 단순평판의 진동을 해석하기 위하여 파워흐름유한요소법을 적용하였다. 파워흐름해석법에서 주어지는 진동 에너지지배방정식의 해를 구하기 위한 수치해석 도구로써 유한요소법을 활용하였다. 이러한 파워흐름유한요소법을 적용하여 중고주파수 영역에서 진동하는 단순평판의 진동 변위와 진동인텐시티 분포를 구하였다. 또한 수치해 결과를 엄밀해와 유한요소법에 의한 근사해와 비교함으로써, 파워흐름유한요소법은 중고주파수 영역에서 진동 변위 및 진동 인텐시티를 예측하기 위하여 효과적으로 적용될 수 있음을 보였다.