THE ELECTRON MICROSCOPY OF LEAF SURFACES PRESERVED IN PEAT

Phragmites communis, Eriophorum vaginatum, Calluna vulgaris, and Sphagnum palustre are representative of plants whose remains are frequently encountered in Scottish peat deposits. The effects of preservation in peat on the surface features of their leaves were followed by electron microscopy. Wax projections were observed on the surfaces of mature living leaves of Phragmites and Eriophorum but not on Calluna or Sphagnum. Details of cell wall outlines and stomata (or pores) were clearly defined in Phragmites, Eriophorum, and Sphagnum, but obscured in Calluna. The previous year's leaves differed by displaying a general absence of wax projections, an erosion of the cuticular surface, which took the form of either a loss in definition of the cell wall outlines or a definite etching of the surface, and the presence of numerous microorganisms. The surface features of preserved leaves exhibited to a greater degree this erosion of cell wall outline and cuticular surface. This preliminary study has indicated that major alterations in the submicroscopic features of cuticularized leaf surfaces occur at the leaf litter stage. The primary agents responsible for this degradation would appear to be microorganisms in conjunction with the physical and chemical processes of peat formation.

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Application of Scanning Electron Microscopy to Medical Research

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061963 ◽

1969 ◽

Vol 27 ◽

pp. 12-13

Author(s):

J. D. Hutchison

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Medical Research ◽

Prosthetic Heart Valve ◽

School Of Medicine ◽

Transmission Electron ◽

Definition Of ◽

Mechanism Of Failure ◽

The Brain ◽

Scanning Electron

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.

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Selection and Preparation of Specific Tissue Regions For Tem Using Large Epoxy-Embedded Blocks

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007206x ◽

1973 ◽

Vol 31 ◽

pp. 324-325 ◽

Cited By ~ 1

Author(s):

P. M. Lowrie ◽

W. S. Tyler

Keyword(s):

Electron Microscopy ◽

Anatomical Structures ◽

Ultrastructural Studies ◽

Transmission Electron ◽

Microscopic Evaluation ◽

Embedded Blocks ◽

Specific Tissue ◽

Definition Of ◽

Areas Of Interest ◽

Selection Of

The importance of examining stained 1 to 2μ plastic sections by light microscopy has long been recognized, both for increased definition of many histologic features and for selection of specimen samples to be used in ultrastructural studies. Selection of specimens with specific orien ation relative to anatomical structures becomes of critical importance in ultrastructural investigations of organs such as the lung. The uantity of blocks necessary to locate special areas of interest by random sampling is large, however, and the method is lacking in precision. Several methods have been described for selection of specific areas for electron microscopy using light microscopic evaluation of paraffin, epoxy-infiltrated, or epoxy-embedded large blocks from which thick sections were cut. Selected areas from these thick sections were subsequently removed and re-embedded or attached to blank precasted blocks and resectioned for transmission electron microscopy (TEM).

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High resolution electron microscopy of lanthanum phosphate crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108519 ◽

1978 ◽

Vol 36 (1) ◽

pp. 274-275

Author(s):

J. C. Wheatley ◽

J. M. Cowley

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

High Resolution ◽

Petroleum Industry ◽

High Resolution Electron Microscopy ◽

Lanthanum Phosphate ◽

Good Catalyst ◽

Resolution Electron ◽

Good Catalytic Activity ◽

Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

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Silicification of wood-cell walls

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169870 ◽

1994 ◽

Vol 52 ◽

pp. 428-429

Author(s):

S. E. Keckler ◽

D. M. Dabbs ◽

N. Yao ◽

I. A. Aksay

Keyword(s):

Electron Microscopy ◽

Cell Wall ◽

Cell Walls ◽

Lignin Content ◽

Resin Composite ◽

Middle Lamella ◽

Cellulose Fibers ◽

Complex Structures ◽

Rich Region ◽

Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

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A Unifying Principle for a Researcher Learning Safety: Reduce Uncertainty!

10.26434/chemrxiv.5917162.v2 ◽

2018 ◽

Author(s):

Camilla Kao ◽

Russell Furr

Keyword(s):

Decision Making ◽

Best Practices ◽

Mission Statement ◽

Safety Information ◽

Health And Safety ◽

Mission Statements ◽

Definition Of ◽

Physical And Chemical

Conveying safety information to researchers is challenging. A list of rules and best practices often is not remembered thoroughly even by individuals who want to remember everything. Researchers in science thinking according to principles: mathematical, physical, and chemical laws; biological paradigms. They use frameworks and logic, rather than memorization, to achieve the bulk of their work. Can safety be taught to researchers in a manner that matches with how they are trained to think? Is there a principle more defined than "Think safety!" that can help researchers make good decisions in situations that are complex, new, and demanding?<div><br></div><div>Effective trainings in other professions can arise from the use of a mission statement that participants internalize as a mental framework or model for future decision-making. We propose that mission statements incorporating the concept of <b>reducing uncertainty</b> could provide such a framework for learning safety. This essay briefly explains the definition of <b>uncertainty</b> in the context of health and safety, discusses the need for an individual to <b>personalize</b> a mission statement in order to internalize it, and connects the idea of <b>greater control</b> over a situation with less uncertainty with respect to safety. The principle of reducing uncertainty might also help <b>non-researchers</b> think about safety. People from all walks of life should be able to understand that more control over their situations provides more protection for them, their colleagues, and the environment.</div>

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Some small-sized Cosmarium (Conjugatophyceae, Desmidiales) from sphagnum bogs of Moscow Region

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2013.47.13 ◽

2013 ◽

Vol 47 ◽

pp. 13-20

Author(s):

O. V. Anissimova

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Cell Wall ◽

Moscow Region ◽

Biological Station ◽

Sphagnum Bogs ◽

Different Seasons ◽

Scanning Electron

Algae samples were collected during different seasons from 1997 to 2011 in two swamps located at Zvenigorod Biological Station in Moscow Region. There were found 25 Cosmarium species and varieties, 9 taxa of them being new to the region. Descriptions of the taxa were specified by observation of cell wall ornamentation with light and scanning electron microscopy. Original descriptions, photos and drawings of algae are presented.

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Effect of Exogenously Applied 24-Epibrassinolide and Brassinazole on Xylogenesis and Microdistribution of Cell Wall Polymers in Leucaena leucocephala (Lam) De Wit

Journal of Plant Growth Regulation ◽

10.1007/s00344-021-10313-6 ◽

2021 ◽

Author(s):

S. Pramod ◽

M. Anju ◽

H. Rajesh ◽

A. Thulaseedharan ◽

Karumanchi S. Rao

Keyword(s):

Electron Microscopy ◽

Cell Wall ◽

Leucaena Leucocephala ◽

Higher Plants ◽

Lignin Content ◽

Wood Quality ◽

Wall Structure ◽

Vessel Element ◽

Xylem Differentiation ◽

Cell Wall Polymers

AbstractPlant growth regulators play a key role in cell wall structure and chemistry of woody plants. Understanding of these regulatory signals is important in advanced research on wood quality improvement in trees. The present study is aimed to investigate the influence of exogenous application of 24-epibrassinolide (EBR) and brassinosteroid inhibitor, brassinazole (BRZ) on wood formation and spatial distribution of cell wall polymers in the xylem tissue of Leucaena leucocephala using light and immuno electron microscopy methods. Brassinazole caused a decrease in cambial activity, xylem differentiation, length and width of fibres, vessel element width and radial extent of xylem suggesting brassinosteroid inhibition has a concomitant impact on cell elongation, expansion and secondary wall deposition. Histochemical studies of 24-epibrassinolide treated plants showed an increase in syringyl lignin content in the xylem cell walls. Fluorescence microscopy and transmission electron microscopy studies revealed the inhomogenous pattern of lignin distribution in the cell corners and middle lamellae region of BRZ treated plants. Immunolocalization studies using LM10 and LM 11 antibodies have shown a drastic change in the micro-distribution pattern of less substituted and highly substituted xylans in the xylem fibres of plants treated with EBR and BRZ. In conclusion, present study demonstrates an important role of brassinosteroid in plant development through regulating xylogenesis and cell wall chemistry in higher plants.

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Characterization of Spent Ni-MH Batteries

Materials Science Forum ◽

10.4028/www.scientific.net/msf.730-732.569 ◽

2012 ◽

Vol 730-732 ◽

pp. 569-574

Author(s):

Marta Cabral ◽

Fernanda Margarido ◽

Carlos A. Nogueira

Keyword(s):

Quantitative Analysis ◽

Electrode Materials ◽

Phase Identification ◽

Recycling Process ◽

X Ray ◽

Leaching Experiments ◽

Plastic Components ◽

Definition Of ◽

Physical And Chemical

Spent Ni-MH batteries are not considered too dangerous for the environment, but they have a considerable economical value due to the chemical composition of electrodes which are highly concentrated in metals. The present work aimed at the physical and chemical characterisation of spent cylindrical and thin prismatic Ni-MH batteries, contributing for a better definition of the recycling process of these spent products. The electrode materials correspond to more than 50% of the batteries weight and contain essentially nickel and rare earths (RE), and other secondary elements (Co, Mn, Al). The remaining components are the steel parts from the external case and supporting grids (near 30%) containing Fe and Ni, and the plastic components (<10%). Elemental quantitative analysis showed that the electrodes are highly concentrated in metals. Phase identification by X-ray powder diffraction combined with chemical analysis and leaching experiments allowed advancing the electrode materials composition. The cathode is essentially constituted by 6% metallic Ni, 66% Ni(OH)2, 4.3% Co(OH)2 and the anode consists mainly in 62% RENi5 and 17% of substitutes and/or additives such as Co, Mn and Al.

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Electron microscopy of the replicative events of A25 bacteriophages in group A streptococci

Canadian Journal of Microbiology ◽

10.1139/m72-015 ◽

1972 ◽

Vol 18 (1) ◽

pp. 93-96 ◽

Cited By ~ 3

Author(s):

S. E. Read ◽

R. W. Reed

Keyword(s):

Electron Microscopy ◽

Cell Wall ◽

Electron Microscope ◽

Nucleic Acid ◽

Group A Streptococcus ◽

Group A Streptococci ◽

Virulent Phage ◽

Acid Pool ◽

Group A ◽

A Cell

The replicative events of a virulent phage (A25) infection of a group A Streptococcus (T253) were studied using the electron microscope. The first intracellular evidence of phage replication in a cell occurred 30 min after infection with arrest of cell division and increase in the nucleic acid pool. Phage heads were evident in the nucleic acid pool of the cells 45 min after infection. Release of phages occurred by splitting of the cell wall along discrete lines. This appeared to be at sites of active wall synthesis, i.e., near the region of septum formation. Many phage components were released but relatively few complete phages indicating a relatively inefficient replicative system.

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