• Applied Microscopy
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• 제38권2호
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• pp.107-115
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• 2008

콩팥의 모세여과관문은 토리모세혈관, 내피세포, 혈관사이바탕질, 토리바닥막, 발세포로 구성되어 있다. 콩팥의 노화가 일어나게 되면 형태학적 변형이 일어난다고 보고되었는데, 그 중 흰쥐의 경우 생쥐나 사람보다 노화에 따른 토리의 형태가 다양하게 관찰된다는 보고가 있다. 하지만 이런 연구들은 대부분 단면 위주로, 형태변화에 관한 입체적인 연구는 부족한 실정이다. 본 연구에서는 3개월이 지난 성숙한 흰쥐와 24개월이 지난 노화 흰쥐의 토리 모세여과관을 비교하여 그에 따른 형태변화를 광학 및 투과전자현미경을 이용하여 관찰하였으며, 이러한 결과를 바탕으로 연속절편을 통해 컴퓨터 프로그램을 기반으로 한 3차원 재구성을 시행하였다. 그 결과 노화 흰쥐의 토리에서 요공간의 확장, 모세혈관 내피세포의 변형, 토리바닥막의 비대, 혈관사이바탕질의 확장을 관찰할 수 있었다. 또한 3차원 재구성을 시행한 결과 노화 흰쥐의 토리에서 바닥막 경계의 붕괴 현상, 발세포 핵막의 조각화와 분절 양상, 발세포 세포돌기의 부분적인 수축과 세포돌기의 가늘어짐으로 인한 여과틈새의 확장을 관찰할 수 있었다. 이상의 결과로 미루어 볼 때, 노화가 진행되면 토리의 여과관문의 변형으로 인하여 콩팥의 생리학적 역할과 조절이 영향을받을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.917-930
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• 2018

Intracellular synthesis of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Meyerozyma guilliermondii KX008616 is reported under aerobic and anaerobic conditions for the first time. The biogenic synthesis of Ag-NP types has been proposed as an easy and cost-effective alternative for various biomedical applications. The interaction of nanoparticles with ethanol production was mentioned. The purified biogenic Ag/AgCl-nanoparticles were characterized by different spectroscopic and microscopic approaches. The purified nanoparticles exhibited a surface plasmon resonance band at 419 and 415 nm, confirming the formation of Ag/AgCl-NPs under aerobic and anaerobic conditions, respectively. The planes of the cubic crystalline phase of the Ag/AgCl-NPs were confirmed by X-ray diffraction. Fourier-transform infrared spectra showed the interactions between the yeast cell constituents and silver ions to form the biogenic Ag/AgCl-NPs. The intracellular Ag/AgCl-NPs synthesized under aerobic condition were homogenous and spherical in shape, with an approximate particle size of 2.5-30nm as denoted by the transmission electron microscopy (TEM). The reaction mixture was optimized by varying reaction parameters, including temperature and pH. Analysis of ultrathin sections of yeast cells by TEM indicated that the biogenic nanoparticles were formed as clusters, known as nanoaggregates, in the cytoplasm or in the inner and outer regions of the cell wall. The study recommends using the biomass of yeast that is used in industrial or fermentation purposes to produce Ag/AgCl-NPs as associated by-products to maximize benefit and to reduce the production cost.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.416-424
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• 2018

Microstructure of oxide formed on Zr-Nb-Sn tube sample was intensively examined by scanning transmission electron microscopy after exposure to simulated primary water chemistry conditions of various concentrations of Zn (0 or 30 ppb) and dissolved hydrogen ($H_2$) (30 or 50 cc/kg) for various durations without applying desirable heat flux. Microstructural analysis indicated that there was no noticeable change in the microstructure of the oxide corresponding to water chemistry changes within the test duration of 100 days (pretransition stage) and no significant difference in the overall thickness of the oxide layer. Equiaxed grains with nano-size pores along the grain boundaries and microcracks were dominant near the water/oxide interface, regardless of water chemistry conditions. As the metal/oxide interface was approached, the number of pores tended to decrease. However, there was no significant effect of $H_2$ concentration between 30 cc/kg and 50 cc/kg on the corrosion of the oxide after free immersion in water at $360^{\circ}C$. The adsorption of Zn on the cladding surface was observed by X-ray photoelectron spectroscopy and detected as ZnO on the outer oxide surface. From the perspective of $OH^-$ ion diffusion and porosity formation, the absence of noticeable effects was discussed further.

• Restorative Dentistry and Endodontics
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• 제47권1호
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• pp.4.1-4.13
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• 2022

Objectives: This study evaluated the effects of different smear layer preparations on the dentin permeability and microtensile bond strength (µTBS) of 2 self-etching adhesives (Clearfil SE Bond [CSE] and Clearfil Tri-S Bond Universal [CTS]) under dynamic pulpal pressure. Materials and Methods: Human third molars were cut into crown segments. The dentin surfaces were prepared using 4 armamentaria: 600-grit SiC paper, coarse diamond burs, superfine diamond burs, and carbide burs. The pulp chamber of each crown segment was connected to a dynamic intra-pulpal pressure simulation apparatus, and the permeability test was done under a pressure of 15 cmH₂O. The relative permeability (%P) was evaluated on the smear layer-covered and bonded dentin surfaces. The teeth were bonded to either of the adhesives under pulpal pressure simulation, and cut into sticks after 24 hours water storage for the µTBS test. The resin-dentin interface and nanoleakage observations were performed using a scanning electron microscope. Statistical comparisons were done using analysis of variance and post hoc tests. Results: Only the method of surface preparation had a significant effect on permeability (p < 0.05). The smear layers created by the carbide and superfine diamond burs yielded the lowest permeability. CSE demonstrated a higher µTBS, with these values in the superfine diamond and carbide bur groups being the highest. Microscopic evaluation of the resin-dentin interface revealed nanoleakage in the coarse diamond bur and SiC paper groups for both adhesives. Conclusions: Superfine diamond and carbide burs can be recommended for dentin preparation with the use of 2-step CSE.

• Asian Journal of Atmospheric Environment
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• 제7권1호
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• pp.1-7
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• 2013

To establish the method for investigating the behavior of aerosol particles deposited on the leaf surface against fog water under natural conditions, scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analysis and wash water analysis by ion chromatography after the washing treatment were performed using leaves of white birch collected from low part of the tree crown and the top of the tree in Sapporo City, Hokkaido, northern Japan. Each of collected leaves was divided into two parts according to the treatment performed: leaf surface (adaxial side) was 1) untreated, and 2) washed with deionized water with a pipette. In untreated samples, many particles of various shapes, including soil particles and organic debris, were deposited on the surface. Particles containing S were found on the surface of samples collected from only low part of the tree crown. After the washing treatment, SEM-EDX analysis revealed that soil particles and particles containing S had been washed off with water, although some particles such as soil particles and organic debris still remained on the leaf surface. The major anion such as $SO{_4}^{2-}$ was detected in wash water of all samples, although the peak of S in X-ray spectra was not detected from samples collected at top of the tree. The combination of SEM-EDX analysis with wash water analysis indicated that $SO{_4}^{2-}$ was deposited on the leaf surface in dissolved state and/or in state of submicron particles. These results suggested that fog water could remove soil particles and particles containing S and $SO{_4}^{2-}$ from the leaf surfaces, but not all particles. There was no difference in sampling position in the tree crown. Our study suggested that combination with SEM-EDX analysis and wash water analysis would be effective for investigation of the behavior of particles on the leaf surface against fog water.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 2005년도 제36차 추계학술대회 및 제4회 HVEM 이용자 워크샵
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• pp.127-129
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• 2005

Bacterial lipopolysaccharide(LPS) is can stimulate the most LPS-responsive cells in the mammalian host. The macrophage response to LPS can protect the host from infection but high levels, contribute to systemic inflammatory response syndrome and destruction of host itself, The previously study, secretory leukocyte pretense inhibitor (SLPI) was known LPS-induced product of macrophage and had the function that antagonizes their LPS-induced activation of pro-inflammation signaling factors. Purpose of this study was to identify the expression of SLPI involving the infection in various cell lines including odontoblast cell line. Therefore, we conducted in vitro researches, which treated the LPS to the MDPC-23, and compared to NIH3T3, RAW264.7. To investigate the expressionof SLPI in mRNA level, the methods was used RT-PCR and western blotting for protein expression of SLPI. Moreover, we performed the scanning electron microscopic (SEM) observation for the morphological change. This work was supported by Korea Science and Engineering Foundation.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3383-3386
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• 2012

SnS thin films were deposited on glasses through metal organic chemical vapor deposition (MOCVD) method at relatively mild conditions, using bis(3-mercapto-1-propanethiolato) tin(II) precursor without toxic $H_2S$ gas. The MOCVD process was carried out in the temperature range of $300-400^{\circ}C$ and the average grain size in fabricated SnS films was about 500 nm. The optical band gap of the SnS film was about 1.3 eV which is in optimal range for harvesting solar radiation energy. The precursor and SnS films were characterized through infrared spectroscopy, nuclear magnetic resonance spectroscopy, DIP-EI mass spectroscopy, elemental analyses, thermal analysis, X-ray diffraction, and field emission scanning electron microscopic analyses.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1722-1726
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• 2013

A kinetic study on nucleophilic substitution reactions of phenyl Y-substituted-phenyl carbonates (5a-5j) with ethylamine in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$ is reported. The plots of $k_{obsd}$ vs. [amine] are linear for the reactions of substrates possessing a strong electron-withdrawing group (EWG) but curve upward for those of substrates bearing a weak EWG, indicating that the electronic nature of the substituent Y in the leaving group governs the reaction mechanism. The reactions have been concluded to proceed through a stepwise mechanism with one or two intermediates (a zwitterionic tetrahedral intermediate $T^{\pm}$ and its deprotonated form $T^-$) depending on the nature of the substituent Y. Analysis of Bronsted-type plots and dissection of $k_{obsd}$ into microscopic rate constants have revealed that the reactions of substrates possessing a strong EWG (e.g., 5a-5f) proceed through $T^{\pm}$ with its formation being the rate-determining step, while those of substrates bearing a weak EWG (e.g., 5g-5j) proceed through $T^{\pm}$ and $T^-$.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2041-2043
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• 2013

A layered perovskite of Dion-Jacobson phase, $RbLaTa_2O_7$, was successfully exfoliated into colloidal suspension via successive ion-exchange and intercalation reaction. The pristine perovskite $RbLaTa_2O_7$ was synthesized by conventional solid-state reaction, and then, it was ion-exchanged with hydrochloric acid to obtain a protonic form of perovskite. The resulting proton-exchanged perovskite was reacted with ethylamine to increase interlayer spaces for further intercalation reaction. Finally, the ethylamine-intercalated form was exfoliated into nanosheets via an intercalation of bulky organic cations (tetrabutylammonium). According to X-ray diffraction (XRD) analysis, the TBA-intercalated form showed remarkably increased interlayer spacing (${\Delta}d$ = 1.67 nm) in comparison with that of the pristine material. Transmission electron microscopic image of exfoliated perovskite clearly revealed that the present exfoliated perovskite were composed of very thin layers. This exfoliated perovskite nanosheets could be applicable as building blocks for fabricating functional nanocomposites.

• 한국축산식품학회지
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• 제38권1호
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• pp.14-25
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• 2018

Chemical compositions, trypsin inhibitory activity, and gelling properties of albumen from duck egg during salting of 30 days were studied. As the salting time increased, moisture content decreased, the salt content and surface hydrophobicity increased (p<0.05). Trypsin inhibitory activity and specific activity were continuously decreased throughout the salting time of 30 days (p<0.05). This coincided with the decrease in band intensity of inhibitor with molecular weight of 44 kDa as examined by inhibitory activity staining. Nevertheless, no differences in protein patterns were observed in albumen during the salting of 30 days. Based on texture profile analysis, hardness, springiness, gumminess, chewiness, and resilience of albumen gel decreased with increasing salting time. Conversely, salted albumen gels exhibited higher cohesiveness and adhesiveness, compared to those of fresh albumen. Scanning electron microscopic study revealed that gel of salted albumen showed the larger voids and less compactness. In general, salting lowered trypsin inhibitory activity and gelling property of albumen from duck egg to some extent. Nevertheless, the salted albumen with the remaining inhibitor could be an alternative additive for surimi or other meat products to prevent proteolysis.