• 한국육종학회지
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• 제42권5호
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• pp.431-438
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• 2010

Anthers of sweet pepper $F_1$ cultivar 'Special' were cultured on Dumas De Vaulx (C medium), supplemented with $0.1mgL^{-1}$ 2, 4-D and $0.1mg{\cdot}L^{-1}$ kinetin with 3% sucrose, and 0.32% phytagel. The calluses obtained were further sub-cultured on Murashige and Skoog (MS) medium without growth regulators for regeneration. Regenerated plantlets were grown in plastic pots under plastic house and characterized their cytological and morphological characters in spring, 2008. Twenty percent plantlets were identified as haploid plants after chromosome and ploidy analysis. Haploid plants contained 12 chromosomes, high stomatal density with small stomatal length as compared to diploid plants. Stomatal length in haploids was 23.3% smaller than diploids. Haploid plants were characterized as small leaf and petiole size, poor vigor, thin stem and short plant height, short internodes and small flower buds, fruit size and fruit weight as compared to diploid plants and most of the haploid fruits were seedless. SP55, SP62, SP68, SP72 and SP77 are found high yielding double haploids with high total soluble content (8.6, 8.7, 9.2, 9.1 and $9.8^{\circ}Brix$, respectively) and desirable fruit shape, and recommended them to exploit as inbred lines for heterosis breeding.

• 생약학회지
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• 제31권3호
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• pp.273-279
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• 2000

Leukotriene $B_4\;(LTB_4)$ is a pro-inflammatory mediator synthesized in myeloid cells from arachidonic acid. Elevated levels of $LTB_4$ have been found in a number of inflammatory diseases and levels are related to disease activity in some of these. Because $LTB_4$ interacts with cells through specific cell surface receptors, $LTB_4$ receptor blockade is the most specific approach to reduce the pathogenic role of $LTB_4$. In order to find $LTB_4$ receptor antagonist from plants, we screened the $LTB_4$ receptor antagonistic activity of the methanol extract and solvent fractions of herbal drugs. The ability of samples to inhibit specific binding of $[^3H]-LTB_4$ to human peripheral neutrophils was used as assay to evaluate the antagonistic activity of plant materials. Among the tested methanol extracts of herbal drugs, Mori Radicis Cortex, Perillae Semen, Armeniacae Semen and Sophorae subprostratae Radix showed potent inhibitory activity above 70% at the concentration of $100\;{mu}g/ml$. The inhibitory activities of $LTB_4$ binding to human neutrophils were evaluated for several solvent fractions at three different concentrations. Especially, hexane soluble fractions of Anemarrhenae Rhizoma and Embeliae Radix, and ethyl acetate soluble fractions of Aristolochiae Fructus, Magnoliae Cortex and Zingiberis Rhizoma crudus showed moderate activity at $25\;{mu}g/ml$. These fractions were promising candidates for the study of the activity-guided chromatographic purification of active compounds. Silica gel column chromatography of hexane soluble fractions of Anemarrhenae Rhizoma and Embeliae Radix gave very active sub-fractions, AA-4 and ES-4, and their inhibition activities of $LTB_4$ binding to human neutrophil at $30\;{mu}g/ml$ were 78% and 62%, respectively. From these results we could anticipate new $LTB_4$ receptor antagonist from herbal drugs, and the block of $LTB_4$ effects may provide beneficial in neutrophil mediated diseases such as inflammation and bronchial asthma.

• 한국축산식품학회지
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• 제35권6호
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• pp.765-771
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• 2015

The development of a sample preparation method and optimization of the analytical instrumentation conditions were performed for the determination of the vitamin B₁₂ content in emulsified baby foods sold on the Korea market. After removal of the milk protein and fats by chloroform extraction and centrifugation, the vitamin B₁₂ was water extracted from the sample. Following filtration of the solution through a nylon filter, the water-soluble extract was purified by solid-phase extraction using a Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The solution eluted from the cartridge was dried under a stream of nitrogen gas and reconstituted with 1 mL of water. The sample solution was injected into an LC-MS/MS system after optimizing the mobile phase for vitamin B₁₂ detection. The calibration curve showed good linearity with the coefficient of correlation (r²) value of 0.9999. The limit of detection was 0.03 µg/L and the limit of quantitation was 0.1 µg/L. The method of detection limit was 0.02 µg/kg. The vitamin B₁₂ recovery from a spiking test was 99.62% for infant formula and 99.46% for cereal-based baby food. The sample preparation method developed in this study would be appropriate for the rapid determination of the vitamin B₁₂ content in infant formula and baby foods with emulsified milk characteristics. The ability to obtain stable results more quickly and efficiently would also allow governments to exercise a more extensive quality control inspection and monitoring of products expected to contain vitamin B₁₂. This method could be implemented in laboratories that require time and labor saving.

• 한국지반공학회논문집
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• 제27권12호
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• pp.17-25
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• 2011

흙입자의 구조는 흙을 구성하는 용해성 입자의 용해작용, 건조작용 그리고 고결화 현상과 같은 특정요인에 의해 영향을 받으며 입자구조의 변화는 흙의 역학적 거동에 큰 영향을 미친다. 본 논문에서는 흙속에 포함된 용해성입자의 용해작용이 전단강도에 미치는 영향을 조사하였다. 직접전단실험을 위해 소금과 모래로 구성된 혼합재를 이용하여 시료를 조성하고 전체시료에 대한 용해성 입자의 부피비를 조절하면서 실험을 수행하였으며 실험과 동일한 조건하에 서 수치해석을 수행하였다. 입자의 소실과정을 위해 실험에서는 소금-모래 혼합재를 포화시켜 소금을 용해시켰으며 수치해석에서는 용해성 입자의 크기를 줄이는 것으로 용해과정을 모사하였다. 실험결과, 용해성 입자의 부피비가 증가할수록 내부마찰각은 감소하였고, 시료의 수직변형은 팽창거동에서 수축거동으로 변화하였다. 수치해석은 실험 결과와 유사한 거시적 거동을 보여주었다. 미시적관점에서, 입자가 용해됨에 따라 간극비의 증가, 접촉점 수의 감소, 전단접촉력의 증가, 접촉력 연결고리의 이방성에 의해 새로운 입자구조가 생성됨을 보여주었다. 이러한 미시적 거동의 변화는 입자의 용해작용 후 전단거동에 영향을 주게 된다. 본 연구에서는 기초나 지반구조물의 설계와 시공 시 지반재료의 용해에 따른 전단강도을 고려해야 함을 보여준다.

• 전기화학회지
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• 제18권1호
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• pp.17-23
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• 2015

$Li_4Ti_5O_{12}$는 우수한 안정성으로 자동차용 리튬 이온 이차전지의 음극 활물질로서 각광 받고 있다. 그러나 넓은 밴드갭에 기인한 절연체 특성으로 고율 충/방전을 가능하게 하기 위해서는 전자 전도도의 개선이 필수적이다. 본 연구에서는 Cr 도핑을 통해 $Li_4Ti_5O_{12}$의 전자 전도도 개선을 목표로 하였으며, wet-mixing법을 통한 물질 합성시 도판트인 Cr 프리커서의 용해도 차이에 의한 Cr-doped $Li_4Ti_5O_{12}$의 전기화학적 특성 변화를 고찰하고자 하였다. 시료의 물리적 특성은 ICP, XRD, SEM, EXAFS을 통하여 확인하였고 1.0V~3.0V (vs. $Li/Li^+$) 하에서 충/방전 특성을 조사하였다. 프리커서의 용해도는 합성된 물질의 상(phase) 및 모폴로지에 큰 영향을 미쳤으며, 가장 용해도가 높은 $Cr(NO_3)_2$ 프리커서로부터 합성된 경우 Bare $Li_4Ti_5O_{12}$와 비교하여 약 2배 개선된 고율 충/방전 특성(130 mAh/g @ 10 C)을 확인하였다.

• 해양환경안전학회지
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• 제22권2호
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• pp.253-258
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• 2016

선박 및 해양구조물에서의 생물학적 오손을 방지하기 위하여 나노크기의 $MnO_x-WO_3-TiO_2$ 분말을 졸겔법으로 합성하여 특성을 제어하였고, 입자의 결정과 미세구조 등 분체특성 평가를 실시하였다. 자기마모형 방오도료의 안료에 적용하기 위하여 수지에 첨가된 $TiO_2$계 나노분말 안료의 함량에 따른 표면특성 및 방오성능을 확인하였다. $TiO_2$계 안료의 분체특성으로 비표면적은 약 $90m^2/g$, 입자크기는 약 100 ~ 150 nm을 보였다. 텅스텐 산화물은 망간산화물과 티타늄산화물과 상관관계를 통해, 삼원계 분체가 분체특성 및 표면특성이 우수하였다. 망간산화물의 첨가는 독특한 산화환원 특성으로 인하여 방오성능을 증가시키고, 텅스텐 산화물은 안료의 분체특성을 향상시킴으로, 안료와 수지의 비율을 조절하여 분산성, 표면특성 및 방오성능을 제어하였다. 그 결과로, 분산성 및 표면특성에 있어서 1, 5 wt. % 안료가 첨가된 것이 일부 우수하였으나, 5개월 동안의 해상침지시험에서는 2 wt. % 함유된 시편이 높은 방오성능을 보여 해양구조물의 방오안료 적용가능성을 확인하였다.

• 한국세라믹학회지
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• 제39권5호
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• pp.490-497
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• 2002

$CaO-SiO_2-B_2O_3$계의 결정화유리의 소결 특성 및 기계적 특성, 생체활성을 알아보았다. 이 조성의 결정화유리는 750-830${\circ}$ 사이에서 소결 되었으며 치밀한 미세구조를 보였다. 이 결정화 유리는 단사정계 월라스토나이트(monoclinic wollastonite), 칼슘보레이트(Calcium borate, $CaB_2O_4$) 결정상과 보로실리케이트(borosilicate) 유리 기지상(matrix)의 3상으로 구성되었다. 기계적 강도는 지금까지 알려진 다른 생체활성 세라믹스보다 우수하였으며 특히 압축강도(2813 MPa), 파괴인성($3.12 MPa{\cdot}m^{1/2}$)이 높았다. 생체활성은 결정화유리 중 calcium borate와 보로실리케이트 유리의 양에 의존하였는데, 용해도가 높은 calcium borate는 의사체액(SBF)의 칼슘이온의 과포화도를 상승시키고 borosilicate 유리는 탄산아파타이트 핵생성에 필요한Si-OH기를 형성시켜 탄산아파타이트 층이 빨리 생성되기 때문으로 판단된다. 따라서 $CaB_2O_4$와 borosilicate 유리가 많을수록 결정화유리의 생체활성이 뛰어난 것으로 생각된다.

• Journal of Dairy Science and Biotechnology
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• 제38권3호
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• pp.161-167
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• 2020

Cheese pizzas fortified with casein phosphopeptide (CPP) and calcium were subjected to an in vitro digestion to assess whether CPP could prevent the precipitation of calcium. The total calcium content of the cheese pizzas was adjusted to 1,000 mg per pizza (~370 g) with the addition of calcium originating from eggshells. Two levels of trypsin-digested caseins (367 and 459 mg), with a CPP content of ~20%, were added to each pizza. The in vitro digested pizzas were then centrifuged and the supernatant was mixed with Na₂HPO₃ at 37℃ to estimate the possible soluble effect of CPP on calcium. After 24 h of reaction, the solution was centrifuged and the calcium content in the resultant supernatant was analyzed by inductively coupled plasma-atomic emission spectroscopy. One-way statistical analyses showed that CPP had a positive effect on the solubilization of calcium against phosphate (p<0.05). Cheese pizza supplemented with 459 mg of CPP powder was able to prevent precipitation of calcium by 98.8%, whereas no CPP-added cheese pizza solubilized 86.4% of the calcium. A sensory test was also carried out, revealing that panelists could not discern the bitter taste of the CPP added to the pizzas.

• 한국의류학회지
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• 제34권11호
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• pp.1767-1778
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• 2010

This study investigates applying $TiO_2$ (titanium dioxide) nanoparticles to polypropylene nonwoven fabrics via electrospinning for the development of UV-protective materials. To fabricate uniform nanocomposite fibers, three types of $TiO_2$ nanoparticles were applied: powder, colloid, and $TiO_2$ coated polymer pellets. $TiO_2$/polyurethane (PU) and $TiO_2$/poly(vinyl alcohol) (PVA) nanocomposite fibers were electrospun and the morphology was examined using a field-emission scanning electron microscope and a transmission electron microscope. Layered fabric systems with electrospun $TiO_2$ nanocomposite fiber webs were developed at various concentrations of $TiO_2$ in a range of the web area density. The effects of $TiO_2$ concentration and web area density on UV-protective properties were examined. When $TiO_2$ colloid was added into a PVA polymer solution, uniform nanocomposite fiber webs in which $TiO_2$ particles were evenly dispersed were produced. Water-soluble PVA nanofiber webs were given a heat treatment to stabilize the electrospun PVA fibrous structure against dissolution in water. $TiO_2$/PVA nanoeomposite fiber webs with 2wt% $TiO_2$ and 3.0g/$m^2$ web area density exhibited an ultraviolet protection factor of greater than 50, indicating excellent UV protection.

• 한국대기환경학회지
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• 제28권4호
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• pp.384-395
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• 2012

This study was performed to develop the source profiles for fine particles ($PM_{2.5}$) emitted from the biomass burning. The multi-method research strategy included a usage of combustion devices such as field burning, fireplace, and residential wood burning to burn rice straw, fallen leaves, pine tree, and oak tree. The data were collected from multiple sources and measured water-soluble ions, elements, elemental carbon (EC), and organic carbon (OC). From this study, it turned out that OC (34~67%) and EC (1.2~39%) are the major components emitted from biomass burning. In the case of burning rice straw at field burning, OC (66.6%) was the most abundant species, followed by EC (4.3%), $Cl^-$ (3.6%), Cl (2.1%), and $SO^{2-}_4$(1.9%). Burning rice straw, fallen leaves, pine tree, and oak tree at fireplace, the amount of OC was 58.5%, 52.7%, 52.5%, and 61.2%, and that of EC was 1.2%, 18.4%, 36.5%, and 2.7%, respectively. The ratio of OC for the burning of pine tree and oak tree from the residential wood burning device was 56.9% and 34.3%, and that of EC was 25% and 38.6%, respectively. Applying the measured data with respect to the proportion of components emitted from biomass burning to reference model, it turned out that self-diagnosed result was appropriate level, and the result based on the model is in highly corresponding to actual timing of biomass burning.