scholarly journals The multi-layered protective cuticle of Collembola: a chemical analysis

2014 ◽  
Vol 11 (99) ◽  
pp. 20140619 ◽  
Author(s):  
Julia Nickerl ◽  
Mikhail Tsurkan ◽  
René Hensel ◽  
Christoph Neinhuis ◽  
Carsten Werner
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Decisive Role ◽  
Arthropod Cuticle ◽  
Characteristic Layers ◽  
Protein Rich ◽  
Base Structure ◽  
Soil Habitat

Collembola, also known as springtails, are soil-dwelling arthropods that typically respire through the cuticle. To avoid suffocating in wet conditions, Collembola have evolved a complex, hierarchically nanostructured, cuticle surface that repels water with remarkable efficiency. In order to gain a more profound understanding of the cuticle characteristics, the chemical composition and architecture of the cuticle of Tetrodontophora bielanensis was studied. A stepwise removal of the different cuticle layers enabled controlled access to each layer that could be analysed separately by chemical spectrometry methods and electron microscopy. We found a cuticle composition that consisted of three characteristic layers, namely, a chitin-rich lamellar base structure overlaid by protein-rich nanostructures, and a lipid-rich envelope. The specific functions, composition and biological characteristics of each cuticle layer are discussed with respect to adaptations of Collembola to their soil habitat. It was found that the non-wetting characteristics base on a rather typical arthropod cuticle surface chemistry which confirms the decisive role of the cuticle topography.

Effect of Seedings on the Microstructure of Hydrated Alumina

2012 ◽  
Vol 554-556 ◽  
pp. 709-713
Author(s):  
Yan Hong Liu ◽  
Hong Wen Ma ◽  
Mei Tang Liu
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Decisive Role ◽  
Mechanism Study ◽  
Hydrated Alumina ◽  
Crystal Nucleus ◽  
X Ray ◽  
Intrinsic Mechanism ◽  
Scanning Electron

The morphology and particle size of boehmite play a decisive role on the application of alumina that derived from it. In this paper, we employed pseudoboehmite that produced from Al2 (SO4)3•18H2O and NH3•H2O at 70 °C, pH 7.5 as precursor to synthesize boehmite, and utilized different seeding when preparing pseudoboehmite and boehmite. To identify the influence of seeding on the microstructure of pseudoboehmite and boehmite, the products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and BET. The results indicate that the pseudoboehmite seeding has a significant influence on the morphology and particle size of pseudoboehmite to which we should pay high attention. However, the boehmite seeding does not play the role of crystal nucleus as expected. The further intrinsic mechanism study is ongoing.

Interaction of Al-Si Alloys with SiC/C Ceramic Particles and their Influence on Microstructure of Composites

2011 ◽  
Vol 176 ◽  
pp. 55-62 ◽  
Author(s):  
Anna J. Dolata
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Chemical Elements ◽  
Chemical Compositions ◽  
Structural Studies ◽  
Liquid Aluminium ◽  
Ceramic Particles ◽  
Scanning Electron

Interaction of Al-Si alloys with SiC/C ceramic particles and their influence on microstructure of composites was discussed. This article presents a significant effect of modifying additives introduced into liquid aluminium. As it was shown in the research, Mg and Sr modifiers improve wetting conditions in Al/SiCp+Cp systems, as well as influence the composite’s structure and the structure of the interface between the components. The microstructure observations were performed using light microscopy (OLYMPUS GX 71) and scanning electron microscopy (PHILIPS XL30). Moreover, local analyses of chemical compositions as well as chemical elements mapping were performed using an EDX module for microarea chemical analysis. Based on structural studies, it was found that chemical composition of the aluminium alloy and its modification are equally important parameters.

Ultrastructure, chemical composition, and recrystallization of epicuticular waxes: transversely ridged rodlets

1999 ◽  
Vol 77 (5) ◽  
pp. 706-720 ◽  
Author(s):  
Iris Meusel ◽  
Christoph Neinhuis ◽  
Claus Markstädter ◽  
Wilhelm Barthlott
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Self Assembly ◽  
Crystallization Process ◽  
Plant Cuticle ◽  
Epicuticular Waxes ◽  
Chemical Analyses ◽  
Similar Mode ◽  
Scanning Electron

Transversely ridged rodlets (Aristolochia-type) are of high systematic significance characterizing the ancestral Aristolochiales, Magnoliales, and Laurales. Sporadically, they also occur in various unrelated derived taxa. The ultrastructure, chemistry, and recrystallization of epicuticular waxes of nine species were investigated by high resolution scanning electron microscopy, gas chromatography, and mass spectrometry. Chemical analyses show that transversely ridged rodlets clearly differ in their composition. Waxes of one group are characterized by ketones, whereas a second group completely lacks ketones and is dominated by alkanes. Hentriacontan-16-one (palmitone) was found to be characteristic for transversely ridged rodlets of Aristolochia, Laurus, and Paeonia. Standard solutions were taken for recrystallization experiments under different conditions of solvent, crystallization velocity, and temperature. It was shown that transversely ridged rodlets or related crystals grow from total waxes of all species but never crystallize from individual compounds such as alkanes or palmitone. We concluded that transversely ridged crystals are formed by self-assembly based on a slow crystallization process and the presence of additives. This paper shows that transversely ridged rodlets occur convergently within angiosperms based on a similar mode of crystallization but a different chemical composition. The role of palmitone as a chemotaxonomic character of ancestral angiosperms is discussed.Key words: plant cuticle, epicuticular waxes, chemistry, ultrastructure, recrystallization, systematics.

Mineralogy of a hydrothermal sequence in a core from the Atlantis II Deep, Red Sea

Clay Minerals ◽  
1987 ◽  
Vol 22 (3) ◽  
pp. 251-267 ◽  
Author(s):  
A. Singer ◽  
P. Stoffers
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Red Sea ◽  
Sediment Core ◽  
Depositional Sequence ◽  
The Core ◽  
Atlantis Ii Deep

AbstractThe clay fractions from a 1191-cm long sediment core in the SW Basin of the Atlantis II Deep, Red Sea, were investigated by XRD, electron microscopy and chemical analysis. Talc dominates in the botton portion of the core, near the brine discharge vent. At 1183 cm depth, the clay consists of vermiculite/chlorite and chrysotile. These minerals are of hydrothermal origin and two possible formation pathways are proposed: (i) vermiculite/chlorite and chrysotile formed by the submarine alteration of previously deposited talc; (ii) vermiculite/chlorite and chrysotile authigenically precipitated as a result of changes in the chemical composition of the brine. At 1170 cm depth, a new depositional sequence results from the progressive alteration of swelling 2:1 minerals into vermiculite. At 1025 cm, Mg-rich clay minerals such as chlorite, chrysotile and talc again become prominent. The upper part of the core is characterized by a transition from non-expanding Mg-rich clay minerals to Fe-rich expanding clays, principally nontronite. Periodically, the content of well-crystallized oxides such as hematite in the layers increases. At 1025 cm, some of the Fe-oxides have a morphology similar to that of akaganéite. In the uppermost part of the core, iron oxides appear to consist of a poorly crystalline hydrothermal hematite. An attempt has been made to correlate the various mineralogical assemblages geochemically.

Electron Microscopy of Metal-Matrix Composites

1970 ◽  
Vol 28 ◽  
pp. 404-405
Author(s):  
A. Lawley ◽  
M. R. Pinnel ◽  
A. Pattnaik
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Critical Evaluation ◽  
Elastic Behavior ◽  
Matrix Composites ◽  
Directionally Solidified ◽  
Fracture Characteristics ◽  
Broad Program

As part of a broad program on composite materials, the role of the interface on the micromechanics of deformation of metal-matrix composites is being studied. The approach is to correlate elastic behavior, micro and macroyielding, flow, and fracture behavior with associated structural detail (dislocation substructure, fracture characteristics) and stress-state. This provides an understanding of the mode of deformation from an atomistic viewpoint; a critical evaluation can then be made of existing models of composite behavior based on continuum mechanics. This paper covers the electron microscopy (transmission, fractography, scanning microscopy) of two distinct forms of composite material: conventional fiber-reinforced (aluminum-stainless steel) and directionally solidified eutectic alloys (aluminum-copper). In the former, the interface is in the form of a compound and/or solid solution whereas in directionally solidified alloys, the interface consists of a precise crystallographic boundary between the two constituents of the eutectic.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Analytical electron microscopy of grain boundaries in Al-Cu metallizations

1992 ◽  
Vol 50 (2) ◽  
pp. 1684-1685
Author(s):  
J. R. Michael ◽  
A. D. Romig ◽  
D. R. Frear
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Failure Mode ◽  
Current Density ◽  
Thermal History ◽  
Analytical Electron Microscopy ◽  
Cu Metallization ◽  
Analytical Electron ◽  
Interconnect Lines

Al with additions of Cu is commonly used as the conductor metallizations for integrated circuits, the Cu being added since it improves resistance to electromigration failure. As linewidths decrease to submicrometer dimensions, the current density carried by the interconnect increases dramatically and the probability of electromigration failure increases. To increase the robustness of the interconnect lines to this failure mode, an understanding of the mechanism by which Cu improves resistance to electromigration is needed. A number of theories have been proposed to account for role of Cu on electromigration behavior and many of the theories are dependent of the elemental Cu distribution in the interconnect line. However, there is an incomplete understanding of the distribution of Cu within the Al interconnect as a function of thermal history. In order to understand the role of Cu in reducing electromigration failures better, it is important to characterize the Cu distribution within the microstructure of the Al-Cu metallization.

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