• Title, Summary, Keyword: cryo-SEM

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Observations of the Cyanobacteria Synechocystis sp. PCC 6803 using Cryo-Methods and Cryo-SEM (Cryo-Methods와 Cryo-SEM을 이용한 Cyanobacteria, Synechocystis sp. PCC 6803 미세구조 관찰)

  • Lee, Eun-Ju;Moon, Yoon-Jung;Oh, Hyun-Woo;Kim, Su-Jin;Chung, Young-Ho;Kweon, Hee-Seok;Kim, Youn-Joong
    • Applied Microscopy
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    • v.39 no.1
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    • pp.65-72
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    • 2009
  • Cryo-SEM which enables specimens to be observed in frozen form has been used to study liquid specimens in their native states. Cryo-methods, sample preparation for cryo-SEM, are quite complex and involve several discrete but vitally interconnected steps which are rapid cooling, fracturing, sectioning, etching and coating. It is important to select practical techniques and to optimize conditions of each steps considering analytic purpose and specimen characters, viz., sample dimension, water contents. In this study, etching methods and sample preparation before freezing had been studied for observation of cyanobacteria, Synechocystis sp. PCC 6803 using cryo-SEM and their cryo-SEM images were compared to Conventional SEM (CSEM) images treated by chemical fixation. We could observe the improved morphological images of the pili of the surface and membranes of Synechocystis sp. PCC 6803 and the three-dimensional architectures of their biofilm, which were difficult to observe using chemical fixation and CSEM. These results suggest that cryo-methods/cryo-SEM are useful techniques for morphological study of biological specimen.

Cryo-SEM Methodology of Arabidopsis thaliana Stem Using High-Pressure Freezing (고압동결고정을 이용한 애기장대 줄기의 cryo-SEM 분석법)

  • Choi, Yun-Joung;Lee, Kyung-Hwan;Je, A-Reum;Chae, Hee-Su;Jang, Ji-Hoon;Lee, Eun-Ji;Kweon, Hee-Seok
    • Applied Microscopy
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    • v.42 no.2
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    • pp.111-114
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    • 2012
  • The scanning electron microscopy is an ideal technique for examining plant surface at high resolution. Most hydrate samples, however, must be fix and dehydrate for observation in the scanning electron microscope. Because the microscopes operate under high vacuum, most specimens, especially biological samples, cannot withstand water removal by the vacuum system without morphological distortion. Cryo-techniques can observe in their original morphology and structure without various artifacts from conventional sample preparation. Rapid cooling is the method of choice for preparing plant samples for scanning electron microscopy in a defined physiological state. As one of cryo-technique, high-pressure freezing allows for fixation of native non-pretreated samples up to $200{\mu}M$ thick and 2 mm wide with minimal or no ice crystal damage for the freezing procedure. In this study, we could design to optimize structural preservation and imaging by comparing cryo-SEM and convention SEM preparation, and observe a fine, well preserved Arabidopsis stem's inner ultrastructure using HPF and cryo-SEM. These results would suggest a useful method of cryo-preparation and cryo-SEM for plant tissues, especially intratubule and vacuole rich structure.

An Optimized Methodology to Observe Internal Microstructures of Aloe vera by Cryo-Scanning Electron Microscope

  • Choi, Yoon Mi;Shin, Da Hye;Kim, Chong-Hyeak
    • Applied Microscopy
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    • v.46 no.2
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    • pp.76-82
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    • 2016
  • Aloe vera has been used in the pharmaceutical, food and cosmetic industry for its therapeutic properties. However, there are not many current studies on the microstructure of A. vera compared to studies on the chemical constituents and health efficacy of A. vera. Therefore, we compared the morphology of an A. vera leaf using an optical microscope, a conventional scanning electron microscope (SEM) and a cryo-SEM. Especially, this study focused on observing the gel in the inner leaf of A. vera, which is challenging using standard imaging techniques. We found that cryo-SEM is most suitable method for the observation of highly hydrated biomaterials such as A. vera without removing moisture in samples. In addition, we found the optimal analytical conditions of cryo-SEM. The sublimation conditions of $-100^{\circ}C$ and 10 minutes possibly enable the surface of the inner leaf of A. vera to be observed in their "near life-like" state with retaining moisture. The experiment was repeated with A. arborescens and A. saponaria to confirm the feasibility of the conditions. The results of this study can be applied towards the basic research of aloe and further extend previous knowledge about the surface structures of the various succulent plants.

Influence of Ceramide III on the Structure of a Phospholipid Lamellar Liquid Crystalline Phase Hydrated in Glycerin : Structural and Thermal Behaviors (Glycerin에 수화된 인지질 라멜라 액정상의 구조에 미치는 Ceramide 3의 영향 : 구조적 및 열적거동)

  • Jeong, Kwan-Young;Lee, Dong-Kyu
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.603-609
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    • 2010
  • This paper aims to investigate the lyotropic behaviors of DSPC and CER3 when they are swollen by GLY as a solvent. The analyses were carried out on DSC, XRDs, PM, and Cryo-SEM. CER3 which has its high crystallinity and structural similarity with DSPC was well arranged up to 7.0 wt% in comparison to 20 wt% DSPC without any separation, but it was separated from the liquid crystalline (LC) phase to form another crystalline phase with the expression of its characteristic peak in XRDs and eutectic thermal behavior in DSC. Introducing CER3, two types of patterns were shown in XRD spectra; one is SPP expressed in a normal LC and another is LPP expressed in human skin SC. Therefore, it was confirmed that the incorporation of CER3 makes LC structure more similar to human skin. In Cryo-SEM study, it was shown that CER3 makes LC structure thicker and denser.

Mechanism of Cryogenic Shredding Process of Scrap Tire

  • Taipau Chia;Shanshin Ton;Shu, Hung-Yee;Chien, Yeh-chung;Lee, Ming-Huang
    • Proceedings of the IEEK Conference
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    • pp.225-229
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    • 2001
  • There are about 41% (by weight) of scrap tires were pulverized to produce rubber powder and granules in the tire recycling industry of Taiwan. However, the reuse of the by-products, steel and fiber, of the scrap tires still needs to be improved. It is difficult to remove the remaining rubber on the surface of steel or fiber. This problem reduce the availability for further reuse of steel and fiber. In addition to the improvement of magnetic, gravity separation techniques or carbonization process, using cryogenic shredding process to separate rubber and fiber (or steel) had been used as another alternative. Cryogenic shredding process for scrap tires showed many advantages, the objective of this paper is to explore the mechanisms for the cryogenic shredding process of scrap tires. Cryo-SEM is used to investigate the topographic information, in-situ, from room temperature to -195$^{\circ}C$ . One square inch shredded tire chips are prepared for SEM study. The percentage of the shrinkage of rubber is also estimated, ca. 6.7%. Mechanisms of cryogenic shredding effects on the tire chips are discussed. The proper practice of cryogenic shredding process far scrap tires is also suggested.

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Study on Stability of Ceramides in Liquid Crystalline Emulsions at High Temperature (세라마이드의 액정에멀젼 내 고온 제형 안정성 연구)

  • Hong, Sung Yun;Chang, Yujin;Lee, Jun Bae;Park, Chun Ho;Park, Myung Sam
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.45 no.1
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    • pp.1-7
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    • 2019
  • We introduce to prepare liquid crystalline emulsion composed of cetearyl alcohol, cetyl palmitate, sorbitan palmitate, sorbitan olivate, ceramide and so on which can enforce interface between oil-based particle and water phase. In terms of structural analysis, the stability of the liquid crystalline emulsion including ceramide, which is immisible ingredient, at high temperature was proved by polarized microscope, cryo-SEM, small-angle x-ray scattering, in addition to viscometer and static light scattering by physical analysis.

Effect of Milling Temperature on Formation of Al-Cr-Zr Metal Powder (Al-Cr-Zr 분말형성에 미치는 밀링 온도의 영향)

  • 김현승
    • Journal of Korean Powder Metallurgy Institute
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    • v.7 no.1
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    • pp.19-26
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    • 2000
  • Al-Cr-Zr metal powders were prepared by cryo-milling(-75$^{\circ}C$),ambi-milling(25$^{\circ}C$) and warm-milling(200$^{\circ}C$) to investige the effect of milling temperature. The morphogical changes and microstructural evolution of Al-6wt.%Cr-3wt.%Zr metal powder ball milling were investigated by SEM, OM and XRD. The cryo-milling at -75$^{\circ}C$ caused the more refinement of powder particle size than ambi-milling and warm-milling. The partic morpholgy of Al-Cr-Zr metal powders changed changes into spheroidal particles at 25$^{\circ}C$and spherical particles at 200$^{\circ}C$The spherical particles were formed by agglomertion and contiuous wrapping of the spheroidal particles. The calculated Al crystallite size in Al-Cr-Zr metal powders by the Scherer equation were refined rapidly for short milling time -75$^{\circ}C$compared with milling at 25$^{\circ}C$ and 200$^{\circ}C$.

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Comparison of Panicle and Spikelet Development in Rice Cultivars Milyang 23 and Koshihikari (벼 품종 밀양 23호와 고시히카리의 유수 및 영화 발달 비교)

  • 강시용
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.5
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    • pp.503-514
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    • 1997
  • The morphogenesis of panicle and spikelet in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in $5000^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicle of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage until heading stage. Although the date of panicle differentiation and heading in Koshihikari earlier than those of Milyang 23. the sequence of panicle development in two cultivars begins when first bract primordium at opposite side of flag-leaf primordium differentiated, synchronously followed by growth of the primary branch primordia (PBPs) and secondary branch primordia (SBPs), spikelet primordia(SPs), glumes as lateral organs on rachilla and organs composing single floret, and successive sporogenesis in the young spikelets continue after the enclosure by lemma and palea. The PBPs are acropetally initiated from the base of the panicle primordium, and the SBPs alternately differentiate from the base of upper PBP which differentiate later than the lower PBP. Spikelet development starts at the top of upper side PBP of the young panicle and continue basipetally even though SBPs continue to develop at the lower primary branch. Each PBP, SBP and SP differentiate with differentiation bract or bract hair cell around the base of each their primordia. The observation could confirm that Milyang 23 has not only 2~3 more defferentiated PBPs, but also more SBPs and SPs especially from middle-lower primary branch, at end of their differentiation stages, as compared to those of Koshihikari.

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Differences in Panicle Structure and Spikelet Degeneration in Two Different Types of Rice Cultivars; Milyang 23 and Koshihikari (벼 품종 밀양 23호와 고시히카리의 수형태와 영화 퇴화 차이)

  • 강시용
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.6
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    • pp.833-840
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    • 1997
  • Differentiation and degeneration of spikelets in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in 5000$^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicles of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage, and investigated about formation position of the differentiation and degeneration spikelet within a panicle of 7 days after heading. The degeneration of spikelet appeared simultaneously throughout panicle just after closure of spikelet by the palea and lemma. Differentiated and degenerated spikelets per panicle were about 240, 80 for Milyang 23 and 87, 6 for Koshihikari, respectively. The spikelets degeneration in Milyang 23 was mainly on the secondary and tertiary branch which were developed from primary branch of middle-basal panicle node and hardly not the spikelets of primary branch, and degeneration rate of secondary and tertiary rachis branch and spikelets for Milyang 23 were 2.5 times greater than those of Koshihikari. The proper relation equation between total differentiation or normal spikelets number per panicle(Y) and each rachis branch number were different between cultivars, Le., Y=5.5X$_1$+3.0X$_2$ for Koshihikari as previously proposed, but those of Milyang 23, Y=5.7X$_1$+3.5X$_2$+2.8X$_3$ for total differentiation spikelets and Y=5.6X$_1$+3.2X$_2$+2.4X$_3$ for normally developed spikelets, where X$_1$, X$_2$, X$_3$ are number of primary, secondary, tertiary rachis branch, respectively.

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Raman Spectroscopy of Irradiated Normoxic Polymethacrylic Acid Gel Dosimeter

  • Bong, Ji-Hye;Choi, Kyu-Seok;Yu, Soo-Chang;Kwon, Soo-Il;Cho, Yu-Ra;Park, Chae-Hee;Park, Hyung-Wook
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.625-629
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    • 2011
  • A quantitative analysis of the decreasing rate of the monomer and increasing rate of the polymerization was made by monitoring radiation level increments using Raman spectroscopy within the therapeutic radiation range for a normoxic polymethacrylic acid gel dosimeter. The gel dosimeter was synthesized by stirring materials such as gelatin, distilled water, methacrylic acid, hydroquinone and tetrakis phosphonium chloride at $50^{\circ}C$, and the synthesized gel was contained in a 10- mm diameter and 32-mm high vial to conduct measurement. 24 hours after gel synthesis, it was irradiated from 0 Gy to 20 Gy by 2 Gy using a Co-60 radiotherapy unit. With use of the Cryo FE-SEM, structural changes in the 0 Gy and 10 Gy gel dosimeters were investigated. The Raman spectra were acquired using 532-nm laser as the excitation source. In accordance with fitting the changes in C-COOH stretching (801 $cm^{-1}$), C=C stretching (1639 $cm^{-1}$) and vinyl $CH_2$ stretching (3114 $cm^{-1}$) vibrational modes for monomer and $CH_2$ bending vibrational mode (1451 $cm^{-1}$) for polymer, sensitive parameter S for each mode was calculated. The values of S for monomer bands and polymer band were ranged in $6.0{\pm}2.6$ Gy and $7.2{\pm}2.3$ Gy, respectively, which shows a relatively good conformity of the decreasing rate of monomer and the increasing rate of polymerization within the range of error.