• Journal of Microbiology and Biotechnology
• /
• v.21 no.1
• /
• pp.20-27
• /
• 2011

The purification and characterization of a $Mn^{2+}$-dependent alkaline serine protease produced by Bacillus pumilus TMS55 were investigated. The enzyme was purified in three steps: concentrating the crude enzyme using ammonium sulfate precipitation, followed by gel filtration and cation-exchange chromatography. The purified protease had a molecular mass of approximately 35 kDa, was highly active over a broad pH range of 7.0 to 12.0, and remained stable over a pH range of 7.5 to 11.5. The optimum temperature for the enzyme activity was found to be $60^{\circ}C$. PMSF and AEBSF (1 mM) significantly inhibited the protease activity, indicating that the protease is a serine protease. $Mn^{2+}$ ions enhanced the activity and stability of the enzyme. In addition, the purified protease remained stable with oxidants ($H_2O_2$, 2%) and organic solvents (25%), such as benzene, hexane, and toluene. Therefore, these characteristics of the protease and its dehairing ability indicate its potential for a wide range of commercial applications.

• Mycobiology
• /
• v.40 no.1
• /
• pp.79-81
• /
• 2012

Cankers are localized dead areas in the bark of stems, branches or twigs of many types of trees and shrubs, and are usually caused by fungi. We observed severe canker symptoms in oak trees located in Gyeongnam province in 2011. A total 31 trees were discovered with cankers of varied size, with an average of $48.5{\times}15.2cm$. Black, half-rounded globular mound shaped stromata were associated with the cankers, and the asci of the fungi associated with the cankers were cylindrical shaped with their spore-bearing parts being up to 84 ${\mu}m$ in length. The average fungal ascospores size was $7.59{\times}4.23{\mu}m$. The internal transcribed spacer sequence for the canker causing fungus showed 99% similarity to the sequence of $Annulohypoxylon$ $truncatum$. In this study, the isolated fungus was precisely described and then compared with fungi of similar taxa.

• Mycobiology
• /
• v.40 no.1
• /
• pp.14-19
• /
• 2012

A $Mariannaea$ fungus was isolated during investigation of an elm tree infested with unidentified beetles. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA sequence, the fungus was identified as $Mariannaea$ $elegans$ var. $elegans$. Fungal growth was better on malt extract agar than on potato dextrose agar and oatmeal agar. Optimal temperature and pH for growth of the fungus were $30^{\circ}C$ and pH 7.0, respectively. The fungus was found to have the ability to produce extracellular enzymes such as amylase, ${\beta}$-glucosidase, cellulase, and protease. This is first report on $M.$ $elegans$ var. $elegans$ in Korea.

• Journal of Animal Science and Technology
• /
• v.62 no.5
• /
• pp.741-752
• /
• 2020

Herein, the in vitro protein digestibility of lyophilized Protaetia brevitarsis larvae flour with and without defatting using 70% ethanol was compared with beef loin. Proximate analysis showed that the defatted larvae contained the highest protein content (p < 0.05). The viable counts of total aerobic bacteria, Escherichia coli, and coliform bacteria decreased significantly after defatting the larval samples with 70% ethanol (p < 0.05). Measurement of α-amino group content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed higher amounts of low molecular weight proteins in the larvae compared to beef loin (p < 0.05). After in vitro digestion, the degree of protein hydrolysis of the digesta was higher for both larvae samples compared to beef loin (p < 0.05). No change was observed in the in vitro larval protein digestibility after defatting. These results highlight the excellent protein digestibility of P. brevitarsis larvae with high protein content. Defatting insect flour with 70% ethanol could enhance microbial safety while maintaining excellent protein digestibility.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.8
• /
• pp.2560-2566
• /
• 2012

The present study investigates how the thermal stability of retinol (vitamin A) encapsulated in polyester nanoparticles is influenced by the types of polyester used for the nanoparticles. A variety of polyester-retinol nanoparticles were prepared with various polyesters like: poly(ethylene adipate), PEA; poly(butylene adipate), PBA; poly(hexamethylene adipate), PHMA; and three polycaprolactones, PCL, of different molecular weights ($M_n$ ~10, 40, and 80K). The chemical stability of retinol in these nanoparticles, monitored in an aqueous solution at $25^{\circ}C$ and $40^{\circ}C$ for 4 weeks, was high in the following order of the nanoparticles prepared with PHMA > PCL 40K > PCL 10K > PCL 80K > PBA~PEA at $25^{\circ}C$ and PCL 10K > PCL 40K > PHMA > PCL 80K > PEA > PBA at $40^{\circ}C$. More importantly, this study has also found that the thermal stability of the retinol in the nanoparticles was closely connected with the melting temperatures of polyesters and polyester nanoparticles. The results were further discussed with possible factors - such as sample preparation condition (or history) and miscibility between the polyesters and retinol - affecting $T_m$ of the polyesters and the nanoparticles.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.6
• /
• pp.3815-3817
• /
• 2013

Background: Breast cancer is a common cancer worldwide. With the establishment of Thailand's population-based cancer registry and availability of complete data from 2002-2011, it is of interest to investigate the epidemiologic and clinic-pathological profiles of breast cancer based on the population-based registry data. Methods: The data of all breast cancer patients in the registry for the period of 2002-2011 were included. All medical records of the patients diagnosed from documents of National Cancer Registry of Thailand were retrieved and the following information abstracted: age, clinical characteristics, and histological variables. Thailand census data for the period of 2002-2011 were used to provide the general population's statistics on age, gender, and other related demographic factors. Results: Over the 10 year-period, 7,711 breast cancer cases were included. The disease incidence under age 40 years was relatively low (4.13/$10^5$) while the incidence in the age groups 40 and older was very high (39.2/$10^5$). The vast majority of breast cancer cases (88.8%) were diagnosed by histology as primary lesions in the breast. The most common of patients with breast cancer (36.4%) had regional lymph node involvement and the most common of histopathology diagnosed in patients (84.2%) was an infiltrating duct carcinoma. Conclusions: This study showed a high incidence of breast cancer in older subjects, and high rate of breast cancer in Thailand. Future studies should explore clinical and molecular disease patterns.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.3
• /
• pp.115-122
• /
• 2004

When porous materials are dried, the particles flocculate into fish-net structure in gel phase. In order to exactly analyze the stress distribution of porous materials during drying process, the elastic tensor of microscopic gel structures has to be predicted considering pore shapes as well as porosities of porous materials. The elastic characteristics of porous materials associated with porosities were predicted analyzing microscopic gel structures with circular and cross pores via homogenization method and the drying processes of the electric porous ceramic insulator were simulated using finite element method (FEM). Comparing analysis results between consideration and negligence of pores, the deformed shape and distributions of temperature and moisture were similar but the residual stress was significantly different.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.33 no.1
• /
• pp.78-82
• /
• 2020

In this study, MOSFETs fabricated on Si-doped, MBE-grown β-Ga₂O₃ are demonstrated. A Si-doped Ga₂O₃ epitaxial layer was grown on a Fe-doped, semi-insulating 1.5 cm × 1 cm Ga₂O₃ substrate using molecular beam epitaxy (MBE). The fabricated devices are circular type MOSFETs with a gate length of 3 ㎛, a source-drain spacing of 20 ㎛, and a gate width of 523 ㎛. The device exhibited a good pinch-off characteristic, a high on-off drain current ratio of approximately 2.7×10⁹, and a high breakdown voltage of 1,080 V, which demonstrates the potential of Ga₂O₃ for power device applications including electric vehicles, railways, and renewable energy.

• Clinical and Experimental Pediatrics
• /
• v.60 no.12
• /
• pp.408-412
• /
• 2017

Combined oxidative phosphorylation deficiency-17 (COXPD-17) is very rare and is caused by homozygous or compound heterozygous mutations in the ELAC2 gene on chromosome 17p12. The ELAC2 gene functions as a mitochondrial tRNA processing gene, and only 4 different pathogenic mutations have been reported in ELAC2-associated mitochondrial dysfunction involving oxidative phosphorylation. Affected patients show various clinical symptoms and prognosis, depending on the genotype. We report a novel mutation in the ELAC2 gene (c.95C>G [p.Pro32Arg], het), in an infant with COXPD-17 who presented with encephalopathy including central apnea and intractable epilepsy, and growth and developmental retardation. During hospitalization, consistently elevated serum lactic acid levels were noted, indicative of mitochondrial dysfunction. The patient suddenly died of shock of unknown cause at 5 months of age. This is the first case report of COXPD-17 in Korea and was diagnosed based on clinical characteristics and genetic analysis.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.432.2-432.2
• /
• 2016

A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.