• Biomaterials and Biomechanics in Bioengineering
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• 제4권1호
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• pp.21-32
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• 2019

Eggshell is a waste material after the usage of egg. In this work, biowaste chicken eggshells were used for preparing carbonated hydroxyapatite (HA) nanoparticles of high purity through aqueous precipitation method at room temperature. The eggshell-derived HA will be a cost-effective bioceramics for biomedical applications and an effective material-recycling technology. Additionally, mulberry leaf extract was used as a template to regulate the morphology, size and crystallinity of HA, and the effects of pH value were also examined. Characterization of the samples was performed by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) was used to determine the size, shape and morphology of HA. The results indicate that only one phase of HA were synthesized in the both absence and presence of mulberry leaf extract at pH of 7 and above, while DCPD or DCPA/DCPD phase was observed at pH 4 condition. The crystallite sizes of the HA samples obviously decreased when adding mulberry leaf extract as a template, while they decreased gradually as the solution pH levels increased. With increasing pH level from 7 to 14, the rod-like HA nanoparticles gradually changed to spherical shape at pH 14. Note that, the obtained product is Mg and Sr containing A- and B-type carbonate HA at alkaline pH and it can be a potential material for biomedical applications.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3841-3848
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• 2022

The effect of modifiers on the optical features and radiation defying ability of the Eu³⁺ ions doped multi constituent glasses was examined. XRD has established the amorphous nature of the specimen. The presence of various functional/fundamental groups in the present glasses was analyzed through FTIR spectra. The physical, structural and elastic traits of the glasses were explored. The variation in the structural compactness of the glass structure according to the incorporated modifier was enlightened to describe their suitability for a better shielding media. For the examined glasses, the metallization criterion value varied in the range 0.613-0.692, indicating the non-metallic character of the glasses with possible nonlinear optical applications. The computed elastic moduli expose the Li-containing glass (BTLi:Eu) to be tightly packed and rigid, which is a requirement for a better shielding channel. Furthermore, the optical bandgap and the Urbach energy values are calculated based on the optical absorption spectra. The evaluated bonding parameters revealed the nature of the fabricated glasses covalent. In addition, we investigated the radiation attenuation attributes of the prepared Eu³⁺ ions doped multi constituent glasses using Phy-X software. We determined the linear attenuation coefficient (LAC) and reported the influence of the five oxides Li₂O₃, CaO, BaO, SrO, and ZnO on the LAC values. The LAC varied between 0.433 and 0.549 cm^-1 at 0.284 MeV. The 39B₂O₃-25TeO₂-15Li₂O₃-10Na₂O-10K₂O-1Eu₂O₃ glass has a much smaller LAC than the other glasses.

• 수산해양기술연구
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• 제23권3호
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• pp.117-126
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• 1987

연구에서는 작동 유체중에 포집되어 있는 불용성 포집 계면층을 통과하는 금속입자 운동에 대한 특성을 조사하기 위하여 상호 불용인 착색 글리세린수용액과 사염화탄소 등의 계면층을 만들고 단일강구를 하강시켜 이 계면을 통과 할 때의 계면의 변화에 의한 유체 이동의 궤적과 그 후연에 생기는 기포체적에 관한 이론해석 및 실험분석을 통하여 다음의 결론을 얻었다. 1. 상층액 내에서의 강구 하강에 의한 유체 이동궤적은 상층액과 하층액의 비중 및 점도가 모두 같은 경우를 제외하고는 상층액의 두께에 영향을 받는다. 2. 하층액의 점도가 상층액의 점도와 같거나 큰 경우의 불용성 계면에서는 용액의 물성치에 관계없이 그 궤적 형상이 일정하고, 하층액의 점도에 의해 지배적이며 그 궤적의 형상은 다음과 같다. (1)/(V-2.35)=0.014+0.038$\mu$l super(-1) + 0.028$\mu$l super(-2). 3. 하층액의 점도가 상층액의 것보다 큰 경우의 유체 이동궤적의 체적은 구의 하강거리와 상하층액의 점도비에 의해 다음과 같다. V(Sr) super(0.34)=7.86a super(-2.08). 4. 후류기포생성체적의 비는 R sub(e)수가 100 이하에서 R sub(e)수에 의존하나 그 이상에서는 M sub(0)수의 영향이 지배적이며 그의 상관식은 다음과 같다. (V sub(w)/V sub(b))M sub(0) super(-0.22)=0.012R sub(e) super(1.53) ; R sub(e)<100. (V sub(w)/V sub(b))M sub(0) super(-0.22)=62.5 ;R sub(e)>100

• Journal of Animal Science and Technology
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• 제44권3호
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• pp.305-314
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• 2002

본 연구의 목적은 자돈시기에 있어서는 열 안정성을 갖는 Saccharomyces cerevisiae (SC)를 첨가하여 성장 및 분중 미생물의 변화에 미치는 영향을 조사하고, 비육돈시기에 있어서는 복합생균제 (complex probiotic : CPB, Phichia anomala ST, Galactomyces geotrichum SR59, Thiobacillus sp.)를 첨가하여 성장 및 분중 가스 발생에 미치는 영향을 평가하기 위하여 실시하였다. 시험 1은 3원 교잡종 자돈 72두를 공시하였으며, 시험개시시 체중은 10.53${\pm}$0.02kg이었다. 시험설계는 옥수수－건조유청－대두박 위주의 사료인 대조구 (CON; 기초사료), 대조구 사료내 SC를 0.2% (SC0.2)와 0.4% 첨가한 구 (SC0.4)로 하였다. 전체 사양시험 기간동안, 일당증체량, 일당사료섭취량 및 사료효율에 있어서는 처리구간에 통계적으로 유의적인 차이를 보이지 않았다. 사양시험 개시 후, 7일과 14일에 채취한 분내 젖산균 균수에 있어서는 SC의 첨가 수준이 증가함에 따라 분내 젖산균 균수가 유의적으로 증가하였다 (linear effect, P$<$0.01). 또한, 대장균수에 있어서는 사양시험 개시 후 7일령에서 SC의 첨가 수준이 증가함에 따라 유의적으로 감소하였다 (linear effect, P$<$0.02; quadratic effect, P$<$0.03). 시험 2는 3원 교잡종 비육돈 45두를 공시하였으며, 시험개시시 체중은 49.71${\pm}$0.45kg이었다. 시험설계는 옥수수－대두박 위주의 사료인 대조구 (CON; 기초사료), 대조구 사료내 CPB를 0.2% (CPB0.2)와 0.3% 첨가한 구 (CPB0.3)로 3개 처리로 하였다. 사양시험기간동안 CPB0.3 처리구가 다른 처리구와 비교하여 일당증체량이 유의적으로 증가하였다 (P$<$0.05). 그러나, 일당사료섭취량 및 사료효율에 있어서는 처리구간에 통계적으로 유의적인 차이를 보이지 않았다. 또한, CPB0.3 처리구가 대조구와 비교하여 건물 및 질소 소화율이 통계적인 차이를 보이면서 높게 평가되었다 (P$<$0.05). 암모니아태 질소 함량에 있어서는 CPB 첨가구가 대조구와 비교하여 유의적인 차이를 보이면서 감소하였으며 (P$<$0.05), 휘발성 지방산중 propionic acid에 있어서는 CPB0.3 처리구가 대조구와 비교하여 통계적인 차이를 보이면서 감소하였다 (P$<$0.05). 결론적으로, 생균제 (SC)의 첨가는 자돈시기에 있어서는 분내 젖산균수의 증가와 대장균수의 감소효과에 영향을 주는 것으로 사료되며, CPB는 비육돈 시기에 있어서 성장 및 영양소 소화율을 향상시키고 분내 가스 발생작용을 감소시키는 것으로 사료된다.

• IMMUNE NETWORK
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• 제13권4호
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• pp.123-132
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• 2013

Obesity is consistently increasing in prevalence and can trigger insulin resistance and type 2 diabetes. Many lines of evidence have shown that macrophages play a major role in inflammation associated with obesity. This study was conducted to determine metformin, a widely prescribed drug for type 2 diabetes, would regulate inflammation through down-regulation of scavenger receptors in macrophages from obesity-induced type 2 diabetes. RAW 264.7 cells and peritoneal macrophages were stimulated with LPS to induce inflammation, and C57BL/6N mice were fed a high-fat diet to generate obesity-induced type 2 diabetes mice. Metformin reduced the production of NO, $PGE_2$ and pro-inflammatory cytokines ($IL-1{\beta}$, IL-6 and $TNF-{\alpha}$) through down-regulation of $NF-{\kappa}B$ translocation in macrophages in a dose-dependent manner. On the other hand, the protein expressions of anti-inflammatory cytokines, IL-4 and IL-10, were enhanced or maintained by metformin. Also, metformin suppressed secretion of $TNF-{\alpha}$ and reduced the protein and mRNA expression of $TNF-{\alpha}$ in obese mice as well as in macrophages. The expression of scavenger receptors, CD36 and SR-A, were attenuated by metformin in macrophages and obese mice. These results suggest that metformin may attenuate inflammatory responses by suppressing the production of $TNF-{\alpha}$ and the expressions of scavenger receptors.

• 한국세라믹학회지
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• 제56권2호
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• pp.197-204
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• 2019

An electrochemical oxygen permeating membrane (OPM) is fabricated using Zr_0.895Sc_0.095Ce_0.005Gd_0.005O_2-δ (ScCeGdZ) as the solid electrolyte and aLa_0.7Sr_0.3MnO₃-bScCeGdZ composite (LZab, electrode) as the electrode. The crystal phase of the electrode and the microstructure of the membrane is investigated with X-ray diffraction and scanning electron microscopy. The electrochemical resistance of the membrane is examined using 2-p ac impedance spectroscopy, and LZ55 shows the lowest electrode resistance among LZ82, LZ55 and LZ37. The oxygen permeation is studied with an oxygen permeation cell with a zirconia oxygen sensor. The oxygen flux of the OPM with LZ55 is nearly consistent with the theoretical value calculated from Faraday's Law below a critical current. However, it becomes saturated above the critical current due to the limit of the oxygen ionic conduction of the OPM. The OPM with LZ55 has a very high oxygen permeation flux of ~ 3.5 × 10^-6 mol/㎠s in I = 1.4 A/㎠.

• International Journal of Industrial Entomology and Biomaterials
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• 제44권2호
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• pp.55-64
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• 2022

Bombyx shini Park & Sohn, 2002 (Lepidoptera: Bombycidae), which was listed as an endemic species in South Korea has recently been renamed as the East Asian silk moth Rotunda rotundapex Miyata & Kishida, 1990 (Lepidoptera: Bombycidae). In this study, we sequenced the complete mitochondrial genome (mitogenome) of the R. rotundapex to announce genomic characteristics and to clarify its validity with a new name. The 15,294-bp long complete mitogenome comprises a typical set of genes [13 protein-coding genes (PCGs), 2 rRNA genes, and 22 tRNA genes] and one major noncoding, A + T-rich region, with an arrangement identical to that observed in most lepidopteran mitogenomes. The A/T content of the whole mitogenome was 79.22%; however, it varied among the regions/genes as follows: A + T-rich region, 91.62%; srRNA, 84.67%; lrRNA, 83.01%; tRNAs, 81.43%; and PCGs, 77.46%. Phylogenetic analyses of 35 species in the Bombycoidea superfamily showed the sister relationship between the families Sphingidae and Bombycidae s. str., with the higher nodal support [bootstrap support (BS) = 78%]. The Saturniidae was placed as the sister to the two families, but the nodal support for this relationship was low (BS = 53%). Current R. rotundapex was placed together with previously reported con-species with the highest nodal support, forming a separate clade from Bombyx, validating that B. shini can have a new genus name, Rotunda. However, the Korean R. rotundapex showed a substantial sequence divergence at 5.28% to that originated from an individual of type locality Taiwan in 1,459-bp of COI sequences. Considering such a high sequence divergence an additional study, which includes morphological and DNA barcoding data from further extensive distributional range maybe is needed for further robust taxonomic conclusion.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1734-1741
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• 2023

This work presents the synthesis and preparation of a new glass system described by the equation of (70-x) B₂O₃-5TeO₂ -20SrCO₃-5ZnO -xBi₂O₃, x = 0, 1, 5, 10, and 15 mol. %, using the melt quenching technique at a melting temperature of 1100 ℃. The photon-shielding characteristics mainly the linear attenuation coefficient (LAC) of the prepared glass samples were evaluated using Monte Carlo (MC) simulation N-particle transport code (MCNP-5) at gamma-ray energy extended from 59 keV to 1408 keV emitted by the radioisotopes Am-241, Ba-133, Cs-137, Co-60, Na-22, and Eu-152. Furthermore, we observed that the Bi₂O₃ content of the glasses had a significantly stronger impact on the LAC at 59 and 356 keV. The study of the lead equivalent thickness shows that the performance of fabricated glass sample with 15 mol.% of Bi₂O₃ is four times less than the performance of pure lead at low gamma photon energy while it is enhanced and became two times lower the perforce of pure lead at high energy. Therefore, the fabricated glasses special sample with 15 mol.% of Bi₂O₃ has good shielding properties in low, intermediate, and high energy intervals.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.76-76
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• 2002

본 실험은 Piezo-미세조작기(PrimeTech Ltd., Japan)를 사용하여 마우스 핵이식 후 재구축배를 CZB와 KSOM 두가지 배양액을 사용하여 체외배양성적을 비교 검토하였다. MII의 미수정란은 성숙한 4~5주령 B6D2Fl에 hCG 주사 후 14시간째에 과적 방법을 통해 난관의 팽대부로 부터 회수하였고, metaphase II chromosome-spindle complex와 최소량의 세포질을 내경이 10$\mu\textrm{m}$인 피펫으로 흡입하여 탈핵하였다. 핵이식에 사용된 난구세포(8-l0$\mu\textrm{m}$)는 3시간동안 12% PVP 에처리 하여 piezo-미세조작기를 이용하여 세포질에 세포의 핵을 직접 미세주입 하였다. 핵이식 후 생존한 재구축배는 2시간동안 배양한 후 10mM SrC1$_2$와 5$\mu\textrm{g}$/$m\ell$의 cytochalasin B가 첨가된 $Ca^{2＋}$-free CZB에서 6시간 활성화 처리하였다, 활성화 처리 후 위전핵이 관찰된 재구축란을 CZB 와 KSOM 배지에서 배양하면서 발달률을 비교하였고, 상실배 및 배반포배로 발달한 재구축배를 day 3 대리모에 이식하였다. 표 1에서 보는 바와 같이 재구축배의 2-cell로의 발달률에 있어서 KSOM이 CZB에 비하여 유의적으로 높게 나타났으며(P<0.05), 또한 4-cell과 상실배/배반 포배로의 발달률에 있어서도 KSOM이 CZB에 비하여 유의적으로 높은 발달률을 나타내었다(P<0.01). 또한 KSOM 배지에서 배양된 상실배/배반포배를 대리모에 이식한 경우에 11.5 d.p.c에 생존한 태아가 관찰되었다. 이상의 결과로 핵이식 재구축배의 활성화 처리 후의 발생에는 KSOM 배지가 CZB 배지에 비하여 유효함을 확인 할 수 있었다.그와 같은 배양 기술을 이용하여 외래유전자를 도입한 일련의 결과에 관하여 보고 하고자한다., 이것은 세포내 유전자가 transfection되지 않은 세포도 neo selection에서 선발된다는 것을 제시하고 있다. 따라서 체세포를 이용한 형질전환동물 생산을 위해서는 세포내 유전자 도입과 선발 과정에서 나타난 colony에 대하여 보다 엄격한 screen을 하는 것이 필요한 것으로 생각된다.로 우점하였다. 여름철 식물플랑크톤 대발생에 영향은 수온과 직산염이 중요하였으나, 부유물질 크게 기여하지 못하였다.애를 확인하고 지도 관점을 파악하는 것을 포함한다. 그러나 본 논문은 역사발생적 수학 학습-지도 원리의 실제적인 적용에 관하여는 기초적인 연구에 지나지 않기 때문에, 역사발생적 원리를 학교수학에 실제적으로 적용하기 위해서는 각각의 내용에 대한 철저한 역사적 분석을 바탕으로 하는 후속 연구가 필요하다./TEX>구성교육${\lrcorner}$이 조선총독부의 관리하에서 실행되었다는 것을, 당시의 사범학교를 중심으로 한 교육조직을 기술한 문헌에 의해 규명시켰다.nd of letter design which represents -natural objects and was popular at the time of Yukjo Dynasty, and there are some documents of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to look into the origin of the letter designs in t

• 대한기계학회논문집B
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• 제24권4호
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• pp.589-598
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• 2000

A pilot-scale Spray Drying Sorber (SDS) system was set up to evaluate the effect of spray characteristics on the desulfurization yield. The size distribution and the Sauter Mean Diameters of slurry droplets were measured in advance using the optical size measurement system, Malvern 2600. The desulfurization yield of the drying chamber by size was measured for the conditions of inlet gas and spray injection. As a reagent, 10% limestone slurry of $Ca(OH)_2$ was treated with flue gas containing $SO_2$, and the combustion gas analyzer and gas detectors were attached to measure the $SO_2$ concentration. With a flow rate of 144 Nm3/h and a temperature range of $200{\sim}300^{\circ}C$, the experiments were performed for the Stoichiometric Ratio (SR) of 1.0 to 3.0 and droplet mean diameter of 6.5 to $34.3{\mu}m$. In case of smaller spray droplets, the desulfurization efficiency improved due to the increase of total droplet surface area, while the reduction in evaporation time reduced the contact time between the droplets and $SO_2$ gas. In some typical region of droplet diameter, this negative effect, reduction of contact time, became dominant and the desulfurization yield decreases the desulfurization yield in spite of the expansion in absorption area. These results revealed that there exists the optimal size of spray droplets for a given state, which is determined by the compromise between the total surface area of slurry droplets and the evaporation time of droplets. The measurements also indicated that the inlet temperature of flue gas changes the optimal injection condition by varying the driving force for evaporation. The results confirm that the effect of the evaporation time of slurry droplets should be considered in analyzing the desulfurization yield as well as the total surface area, for it is a significant aspect of the correlation with the capabilities of $SO_2$ absorption in wet droplets. In conclusion, the optimal condition of spray can be determined based on these results, which might be applied to design or scale-up of SDS system.