• Title/Summary/Keyword: scanning EM

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Some living eukaryotes during and after scanning electron microscopy

  • Ki Woo Kim
    • Applied Microscopy
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    • v.51
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    • pp.16.1-16.7
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    • 2021
  • Electron microscopy (EM) is an essential imaging method in biological sciences. Since biological specimens are exposed to radiation and vacuum conditions during EM observations, they die due to chemical bond breakage and desiccation. However, some organisms belonging to the taxa of bacteria, fungi, plants, and animals (including beetles, ticks, and tardigrades) have been reported to survive hostile scanning EM (SEM) conditions since the onset of EM. The surviving organisms were observed (i) without chemical fixation, (ii) after mounting to a precooled cold stage, (iii) using cryo-SEM, or (iv) after coating with a thin polymer layer, respectively. Combined use of these techniques may provide a better condition for preservation and live imaging of multicellular organisms for a long time beyond live-cell EM.

Railway Track Extraction from Mobile Laser Scanning Data (모바일 레이저 스캐닝 데이터로부터 철도 선로 추출에 관한 연구)

  • Yoonseok, Jwa;Gunho, Sohn;Jong Un, Won;Wonchoon, Lee;Nakhyeon, Song
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.33 no.2
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    • pp.111-122
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    • 2015
  • This study purposed on introducing a new automated solution for detecting railway tracks and reconstructing track models from the mobile laser scanning data. The proposed solution completes following procedures; the study initiated with detecting a potential railway region, called Region Of Interest (ROI), and approximating the orientation of railway track trajectory with the raw data. At next, the knowledge-based detection of railway tracks was performed for localizing track candidates in the first strip. In here, a strip -referring the local track search region- is generated in the orthogonal direction to the orientation of track trajectory. Lastly, an initial track model generated over the candidate points, which were detected by GMM-EM (Gaussian Mixture Model-Expectation & Maximization) -based clustering strip- wisely grows to capture all track points of interest and thus converted into geometric track model in the tracking by detection framework. Therefore, the proposed railway track tracking process includes following key features; it is able to reduce the complexity in detecting track points by using a hypothetical track model. Also, it enhances the efficiency of track modeling process by simultaneously capturing track points and modeling tracks that resulted in the minimization of data processing time and cost. The proposed method was developed using the C++ program language and was evaluated by the LiDAR data, which was acquired from MMS over an urban railway track area with a complex railway scene as well.

Characteristics of the Fracture Distribution on the Granitic Rock by DC and VLF-EM Survey in the Northern Part of Yusong (유성북부 화강암지역에서 전기비저항탐사와 극저주파 전자탐사를 이용한 단열분포 특성)

  • 조성현;김천수;송무영
    • The Journal of Engineering Geology
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    • v.9 no.1
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    • pp.45-57
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    • 1999
  • Groundwater flow in rock mass is controlled by the fractures developed in the area. So, the conductive fractures are very important for groundwater flow in crystalline rock. This study aims to find out the characteristics of the fracture distributed in granitic rock in the northern part of the Yusong area (latitude $36^{\circ}24'18"~36^{\circ}25'08",{\;}longitude{\;}127^{\circ}21'00"~127^{\circ}23'23"$). The electric and EM surveys were carried out in the site to delineate the fracture the fracture zones. Since geophysical survey provides non-unique solution, hydraulic data and dilling log data including BHTV scanning were used as complementary data to achieve the objective of this study. Electric survey(DC) arrays used are schlumberger and dipole-dipole arrays. VLF is used for EM survey. The main charcteristics of the fracture developed in the study aera are that fractures associated with basic dyke cut corss the main fracture zone in NNW and play an important role as hydraulic barrier. In trun, groundwater table in the upstream area is lower than that downstream area.

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Effects of Sheet Thickness on the Electromagnetic Wave Absorbing Characterization of Li0.375Ni0.375Zn0.25-Ferrite Composite as a Radiation Absorbent Material

  • Kim, Dong-Young;Yoon, Young-Ho;Jo, Kwan-Jun;Jung, Gil-Bong;An, Chong-Chul
    • Journal of electromagnetic engineering and science
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    • v.16 no.3
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    • pp.150-158
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    • 2016
  • This paper reports on a study of LiNiZn-ferrite composite as a radiation absorbent material (RAM). The electromagnetic (EM) wave absorbers are composed of an EM wave absorbing material and a polymeric binder. The surface morphology, chemical composition, weight percent of the ferrite composite of the toroid sample, magnetic properties, and return loss are investigated using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and network analyzer. For preparing the absorbing sheet, chlorinated polyethylene (CPE) is used as a polymeric binder. The EM wave absorption properties of the prepared samples were studied at 4 - 8 GHz. We can confirm the effects of the thickness of the samples for absorption properties. An absorption bandwidth of more than a 10-dB return loss shifts toward a lower frequency range along with an increase in the thickness of the absorber.

Pressure Induced Structural Changes of Proteins Affecting the Ice Nucleation Temperature of Pork Loins

  • Cho, Youngjae;Lee, Eun-Jung;Lee, Jiseon;Lee, SangYoon;Yun, Young-Chan;Hong, Geun-Pyo
    • Food Science of Animal Resources
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    • v.39 no.6
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    • pp.1008-1014
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    • 2019
  • This study investigated the effects of pressure-mediated protein changes on the ice nucleation temperature of pork loins. To variate chemical state of meat proteins, pork loin was pressurized at varying pressure levels (100-500 MPa) for 3 min, and moisture content, expressible moisture (EM) and differential scanning calorimetry (DSC) were analyzed. Although, all treatments showed similar moisture content, EM and degree of protein unfolding of pork loin showed different features as of 300 MPa. At moderate pressure treatments (100-200 MPa), all protein fractions were detected in DSC experiments, and pork loin had lower EM than control (p<0.05). Meanwhile, myosin and actin of pork loin treated at greater than 300 MPa were completely unfolded, and the treatments showed high EM compared to control (p<0.05). Unfolding of meat proteins was a factor suppressing ice nucleation, and the ice nucleation temperature tended to decrease with increasing applied pressure level. The ice nucleation characteristics of pressurized pork loin exhibited a potential application in freezing storage of pressurized meat with less tissue damage comparing to freeze fresh meat, and further exploration regarding the quality change after freezing of fresh and pressurized meat was warranted.

Preparation of Cyclosporin A-loaded Nanoparticles Containing Ethyl Myristate or Chitosan and Pharmacokinetics in Rats

  • Nam, Dae-Sik;;Lee, Woo-Kyoung
    • Journal of Pharmaceutical Investigation
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    • v.37 no.1
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    • pp.15-22
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    • 2007
  • An oil-in-water solvent evaporation method was used to prepare the cyclosporin A (CyA)-loaded nanoparticles varying in poly (D,L-lactide-co-glycolide) (PLGA) polymer (RG 502H, RG 503H) and the amount of additive ethyl myristate (EM) or chitosan (CS). The particles were characterized for drug loading and entrapment efficiency by HPLC, surface morphology by scanning electron microscopy, particle size by dynamic light scattering and surface charge by Zetapotential. The results showed drug loadings ranging from 10.9% to 15.8% with high encapsulation efficiency (82.0-97.8%). SEM and DLS studies showed discrete and spherical particles with smooth surfaces and mean size ranging 257.6-721.7 nm. The additive EM or CS did not change the mean sizes of the nanoparticles, whereas by the coating effect of CS, the Zetapotential values of the CS-added nanoparticles were moved to the more positive direction as the amount of CS was increased. From the pharmacokinetic analysis, the nanoparticles formulations showed the higher bioavailability and MRT than $Neoral^{\circledR}$ While little adding effect of EM or CS was detected in pharmacokinetic profile when RG 503H was used as polymer carrier, more noticeable different pharmacokinetic behaviors could be observed in case of RC 502H. EM incorporation was found to elevate the $K_{el}$, whereas CS coating resulted in the decrease of F and $K_{el}$, which seems to be due to the function of CS as a barrier and a mucoadhesive coating.

Effects of PCB Surface Finishes on in-situ Intermetallics Growth and Electromigration Characteristics of Sn-3.0Ag-0.5Cu Pb-free Solder Joints (PCB 표면처리에 따른 Sn-3.0Ag-0.5Cu 무연솔더 접합부의 in-situ 금속간 화합물 성장 및 Electromigration 특성 분석)

  • Kim, Sung-Hyuk;Park, Gyu-Tae;Lee, Byeong-Rok;Kim, Jae-Myeong;Yoo, Sehoon;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.2
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    • pp.47-53
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    • 2015
  • The effects of electroless nickel immersion gold (ENIG) and organic solderability preservative (OSP) surface finishes on the in-situ intermetallics reaction and the electromigration (EM) reliability of Sn-3.0Ag-0.5Cu (SAC305) solder bump were systematically investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of the ENIG surface finish at solder top side, while at the OSP surface finish at solder bottom side,$ Cu_6Sn_5$ and $Cu_3Sn$ IMCs were formed. Mean time to failure on SAC305 solder bump at $130^{\circ}C$ with a current density of $5.0{\times}10^3A/cm^2$ was 78.7 hrs. EM open failure was observed at bottom OSP surface finish by fast consumption of Cu atoms when electrons flow from bottom Cu substrate to solder. In-situ scanning electron microscope analysis showed that IMC growth rate of ENIG surface finish was much lower than that of the OSP surface finish. Therefore, EM reliability of ENIG surface finish was higher than that of OSP surface finish due to its superior barrier stability to IMC reaction.

Physicochemical Properties of Starch Granules from Endosperm Mutants in Rice (배유돌연변이체 쌀전분의 이화학적 특성 비교)

  • Kang, Mi-Young;Han, Ji-Yeun;Nam, Seok-Hyun
    • Korean Journal of Food Science and Technology
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    • v.32 no.2
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    • pp.258-264
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    • 2000
  • Starches from the eight varieties of rice were analyzed using scanning electron microscope(SEM), differential scanning calorimetry(DSC) and X-ray diffractometry, and tested on the starch-granule susceptibility to 15% $H_2SO_4$ and glucoamylase. The shape of starch granules from normal rice varieties and low-amylose mutants were polygonal while shrunken and floury mutants were globular. According to DSC, starches from Nampung CB243 showed higher onset temperature$(T_o)$, completion temperature$(T_c)$ and Punchilmi, Nampung EM90 showed higher enthalpy$({\triangle}H)$ of gelatinization than others. shr showed the highest hydrolysis rate to 15% $H_2SO_4$ while Nampung CB243 showed the lowest one. Eight varieties of rice starch granules showed A-type pattern on X-ray diffractograms. The lower amylose content rice varieties showed the higher hydrolysis rate treated with glucoamylase.

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Evaluation of physicochemical and textural properties of chicken breast sausages containing various combinations of salt and sodium tripolyphosphate

  • Choi, Ji Seon;Chin, Koo Bok
    • Journal of Animal Science and Technology
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    • v.62 no.4
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    • pp.577-586
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    • 2020
  • This study was to investigate the effect of salt alone or in combination with phosphate on physicochemical and textural properties, and chemical interactions of low-fat model sausages. pH, color, expressible moisture (EM), cooking loss (CL), proximate analysis, textural profile analysis and low-vacuum scanning electron microscopy were performed. As salt content increased, color tended to decrease, as did EM and CL parameters, indicating that the ability to retain moisture was improved with increased salt levels (p < 0.05). In addition, textural hardness, gumminess and chewiness all increased with increasing salt (p < 0.05). Sausages with 0.3% salt showed the lowest cohesiveness compared to those with salt levels higher than 0.3% (p < 0.05). Addition of sodium tripolyphosphate (STPP) increased pH of sausages. Increasing salt and STPP did not affect lightness (p > 0.05), but did increase redness and yellowness (p < 0.05). The moisture content was higher when the salt and STPP contents were increased (p < 0.05), but no differences in the fat and protein contents (%) were observed (p > 0.05). EM and CL tended to decrease with increasing salt and STPP. In textural properties, the combination of 1.8% salt and 0.3% STPP was the best among other treatment (p < 0.05). Surface microstructure showed a flat and dense structure with increasing salt and STPP. Since the addition of salt and phosphate improved the functionality, textural and physicochemical properties of meat products in this study, meat products will need to be developed in line with consumer's preference.

Biodistribution of Inhaled Titania ($TiO_2$) Nanoparticles in Rats (백서에서 흡인된 티타니아 나노입자의 생체 내 분포에 관한 연구)

  • Choi, Se-Hoon;Park, Kay-Hyun;Jheon, San-Hhoon;Kim, Joo-Hyun;Chung, Jin-Haeng;Cho, So-Hye;Park, Jong-Ku;Kim, Tae-Heon
    • Korean Journal of Bronchoesophagology
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    • v.16 no.1
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    • pp.33-38
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    • 2010
  • Titania nanomaterials are widely used as cosmetics and dyes, however the impacts on human health are uncertain, We investigated the biodistribution of inhaled titania nanoparticles in rats, Methods Eight weeks-old SD rats were intubated and inhaled with 3 mg titania nanoparticles, twice a week, for 2 weeks, After inhalation, the rats were sacrificed and tissues or heart, lung. intestine, brain, and liver were obtained, We investigated the tissues with optical microscope (OM), transmission electron microscope (EM), scanning EM, And to analyze titania concentration of each tissue, we lysed the tissues with radioimmunoprecipitation assay (RlPA) lysis buffer or acid. Results Granulation tissues in lung were confirmed on the optical microscope, however the other organs had no abnormalities in OM images, In EM images, the rats which inhaled titania nanoparticles showed calcium deposition at heart, brain, and intestine, Titania concentration in lung was increased on the inhaled rat sacrificed I month after last exposure. Conclusion Inhaled titania nanoparticles is thought to be deposited and make inflammatory reaction in lung, and the deposition was not efficiently cleared over a month. However inhaled titania nanoparticles may rarely pass through the alveolus-blood barrier and distribute to other organs of the bod.

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