Morphology, microstructure, and development of colonies of Acetobacter xylinum

1978 ◽  
Vol 24 (7) ◽  
pp. 772-779 ◽  
Author(s):  
L. C. Sowden ◽  
J. Ross Colvin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Cell Mass ◽  
Acetobacter Xylinum ◽  
Cellulose Microfibrils ◽  
Dividing Cells ◽  
Scanning Electron

Development of the morphology and microstructure of colonies of Acetobacter xylinum glowing on agar was studied by optical microscopy, and transmission and scanning electron microscopy. The mass of rapidly dividing cells surrounded by a sheath of cellulose microfibrils passes from a smooth spheroid to a flattened aggregate with a characteristic 'pillowed' surface. This morphology is the result of a repeated extrusion of cells from the confining sheath, followed by regeneration of a new portion of the sheath on the extruded cell mass. Relations of this mechanism to others which produce similar shapes are indicated.

The structure of spherulites of bacterial cellulose from Acetobacter xylinum

1974 ◽  
Vol 20 (4) ◽  
pp. 509-512 ◽  
Author(s):  
L. C. Sowden ◽  
J. Ross Colvin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Cellulose ◽  
Acetobacter Xylinum ◽  
Cellulose Microfibrils ◽  
Polarizing Microscopy ◽  
Scanning Electron

Evidence from phase and polarizing microscopy as well as scanning electron microscopy indicates that the cellulose microfibrils in the spherulites of bacterial cellulose are oriented tangentially, not radially. Also, the orientation may be limited to only a fraction of the thickness of the pellicle. It is suggested that the tangential deposition may be caused by a gradient of concentration of a weakly soluble inhibitor of cellulose formation about a center.

Digital imaging: When should one take the plunge?

1996 ◽  
Vol 54 ◽  
pp. 602-603
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Microscopy ◽  
Digital Imaging ◽  
Storage Devices ◽  
Major Benefit ◽  
Transmission Electron ◽  
New Instrument ◽  
Scanning Electron

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quaity positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).The problem for many researchers, however, is that they have perfectly serviceable microscopes that they routinely use that have no digital imaging capabilities with little hope of purchasing a new instrument.

Investigation of Die Tilting of Packages with Single and Multi-chips

2018 ◽  
Author(s):  
Lo Chea Wee ◽  
Tan Sze Yee ◽  
Gan Sue Yin ◽  
Goh Cin Sheng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Beam ◽  
Optical Microscopy ◽  
Device Performance ◽  
Electronic Components ◽  
Area Of Interest ◽  
On Chip ◽  
Scanning Electron

Abstract Advanced package technology often includes multi-chips in one package to accommodate the technology demand on size & functionality. Die tilting leads to poor device performance for all kinds of multi-chip packages such as chip by chip (CbC), chip on chip (CoC), and the package with both CbC and CoC. Traditional die tilting measured by optical microscopy and scanning electron microscopy has capability issue due to wave or electron beam blocking at area of interest by electronic components nearby. In this paper, the feasibility of using profilemeter to investigate die tilting in single and multi-chips is demonstrated. Our results validate that the profilemeter is the most profound metrology for die tilting analysis especially on multi-chip packages, and can achieve an accuracy of <2μm comparable to SEM.

The External Morphology of the Eggs of Culex (Culex) saltanensis (Diptera: Culicidae) Under Scanning Electron Microscopy

2020 ◽  
Author(s):  
J R Santos-Mallet ◽  
T D Balthazar ◽  
A A Oliveira ◽  
W A Marques ◽  
A Q Bastos ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscopy ◽  
Osmium Tetroxide ◽  
Neotropical Region ◽  
External Morphology ◽  
Metal Supports ◽  
Scanning Electron

Abstract The aim of the present study was to describe the morphology of the eggs of Culex (Culex) saltanensis Dyar that occurs in the Neotropical region. Eggs of the Cx. (Cux.) saltanensis were collected at the Mata Atlântica FIOCRUZ campus, fixed in 1% osmium tetroxide, prepared for mounting on metal supports, observed under a scanning electron microscope, and described morphologically. The eggs had a coniform shape with a length of approximately 0.5 mm (505–510 µm) and a width in the median portion of 117 µm (113–123 µm). Upper portion is lined with tubers of irregular shape and varying sizes (0.64–1.31 µm), located on a cross-linked matrix forming bands observed under optical microscopy. The micropyle is encased in a necklace of approximately 6.6-µm plates arranged in a flower-like shape. Comparing Cx. (Cux.) saltanensis eggs with several species of different genera, important divergent characteristics can be observed. However, this study points to the need for new descriptions of eggs of species belonging to the same subgenus in order to analyze if there will be differences between them. Culex (Cux.) saltanensis eggs have particular characteristics not observed in eggs of other Culicidae genera.

Damage Analysis of Heat Resistant Steels

2007 ◽  
Vol 537-538 ◽  
pp. 303-306
Author(s):  
Tamás Bíró ◽  
László Dévényi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Damage Analysis ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Advantages And Disadvantages ◽  
Heat Resistant ◽  
Heat Resistant Steels ◽  
Scanning Electron

This paper shows the result of some metallographical examinations that have been carried out on low-alloyed Cr-Mo-V heat resistant steel. The aim of this research is to present and compare the advantages and disadvantages of the mainly applied metallographical methods. These techniques are optical microscopy, scanning electron microscopy, replica method and special applications of these methods. We have proved that using the investigated methods together gives much more information about the lifetime of the specimen than using these techniques particularly.

scholarly journals Digital Imaging: When Should One Take The Plunge?

1997 ◽  
Vol 5 (4) ◽  
pp. 14-15
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Microscopy ◽  
Digital Imaging ◽  
High Quality ◽  
Storage Devices ◽  
Major Benefit ◽  
Transmission Electron ◽  
Scanning Electron

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quality positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

Determination of cotton fiber maturity and linear density (fineness) by examination of fiber cross-sections. Part 2: A comparison optical and scanning electron microscopy

2014 ◽  
Vol 84 (18) ◽  
pp. 1939-1947 ◽  
Author(s):  
Geoffrey RS Naylor ◽  
Margaret Pate ◽  
Graham J Higgerson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Optical Microscopy ◽  
Cross Sections ◽  
Linear Density ◽  
Wall Area ◽  
Density Values ◽  
Fiber Maturity ◽  
Scanning Electron

Previous researchers established a set of reference cottons with known fiber maturity and linear density (fineness) values based on the analysis of a large number of individual transverse fiber cross-sections viewed under the optical microscope. Part 1 identified that the limited optical resolution of the captured images may be the source of a significant systematic error in the assigned values of cell wall area and hence fiber maturity and linear density values. In this paper the optical microscopy technique was implemented. Individual cross-sections were measured using this approach and also higher resolution and higher magnification images were obtained using scanning electron microscopy. It was found that the data obtained from optical microscopy were similar to the SEM data, with the perimeter being 2% smaller, the cell wall area being 6% larger and the maturity ratio values being 8% higher. It was concluded that the combined approach of utilizing SEM in conjunction with optical imaging is a useful approach for verifying and perhaps correcting the data obtained from optical imaging. Further the SEM images highlighted that the current experimental protocol does not adequately address the challenge of ensuring that the fibers are mounted normal to the plane of cutting the transverse cross-section. Modeling demonstrated that while maturity ratio values are relatively insensitive to this misalignment, measured cell wall area values and hence fiber linear density values will be overestimated. This may be the major source of error associated with the technique and warrants further attention in future studies.

Scanning electron microscopy of the spines of the tunic of the ascidian, Boltenia ovifera

1970 ◽  
Vol 48 (3) ◽  
pp. 475-477 ◽  
Author(s):  
A. K. Mishra ◽  
J. Ross Colvin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Continuous Extension ◽  
Cellulose Microfibrils ◽  
Exterior Surface ◽  
Extracellular Synthesis ◽  
Scanning Electron

The presence of small spines on the exterior surface of the tunic of Boltenia ovifera, which contain axially oriented microfibrils of cellulose, was confirmed by scanning electron microscopy. These spines axe a continuous extension of the mass of the tissue without a recognizable discontinuity between them and the rest of the tunic. They show a trilobed form at their base after preparation for electron microscopy but this may be a result of desiccation. Tips of the spines are blunt and they, as well as the axial microfibrils which compose the shaft, are enclosed in a sheath which seems to be amorphous. On the surface of the tunic, the water-insoluble glycoprotein component is sparsely distributed. The distribution and morphology of these spines pose unusual problems for the mechanism of extracellular synthesis and deposition of cellulose microfibrils.

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