Ultrastructure and anatomy of Macadamia (Proteaceae) kernels

2012 ◽  
Vol 60 (4) ◽  
pp. 291 ◽  
Author(s):  
David A. Walton ◽  
Helen M. Wallace ◽  
Richard Webb
Keyword(s):  
Electron Microscopy ◽  
High Frequency ◽  
Negative Relationship ◽  
Low Frequency ◽  
Mature Embryos ◽  
Macadamia Integrifolia ◽  
Transmission Electron ◽  
Nut Cracking ◽  
Crust Type ◽  
Gap Width

Macadamia integrifolia Maiden & Betche and M. tetraphylla L.A.S.Johnson, and their hybrids, are cultivated for their edible kernels (mature embryos). Some kernels separate into halves (cotyledons) during post-harvest handling, and embryo cuticular characteristics may influence breakage. Some kernels have a gap between cotyledons before nut cracking, and this anatomical feature may be related to breakage. Kernels from cultivars producing high or low frequency of breakage were examined by transmission electron microscopy and scanning electron microscopy to identify differences in inner-cuticular wax. Whole seeds of each cultivar were opened without cracking to measure gaps between cotyledons and determine relationships between gaps and embryo breakage. Kernels from cultivars with low frequency of breakage had inner-epicuticular wax layers that were of the sculptured crust type whereas those of cultivars with high frequency of breakage were mainly of a wax-film type. Gap width and length of kernels separate at nut opening were more than twice those for intact kernels. There was a negative relationship between whole-kernel percentage and gap width between cotyledons.

scholarly journals Noise-induced gastric lesions: a light and electron microscopy study of the rat gastric wall exposed to low frequency noise

2012 ◽  
Vol 49 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Jorge Fonseca ◽  
José Martins-dos-Santos ◽  
Pedro Oliveira ◽  
Nuno Laranjeira ◽  
Artur Aguas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gastric Wall ◽  
Low Frequency ◽  
Collagen Iv ◽  
Control Group ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Transmission Electron ◽  
Significant Difference

CONTEXT: Only a few studies evaluated the digestive alterations caused by low frequency noise (LFN) and most focused only on mucosal alterations. OBJECTIVES: To investigate the morphological injury of LFN-exposed gastric wall, beyond the epithelial layer. METHODS: Wistar rats were exposed to low frequency noise (LFN), during increasing periods, 1 to 13 weeks. A control group was kept in silence. Gastric specimens were studied using: (i) light microscopy with hematoxylin-eosin and immunostaining for collagens; (ii) transmission electron microscopy; (iii) morphometry allowing statistical analysis. RESULTS: Submucosa of all LFN-exposed animals exhibit increased thickness with fibrous proliferation. Transmission electron microscopy showed massive collagen deposition. Immunostaining identified collagen IV as responsible for the increased thickness. Morphometry allowed the demonstration of a significant difference of thickness between control and exposed groups. Vascular alterations included: i) intima proliferation and thickening, rupture of the internal elastic lamina, thrombotic changes; ii) thickening of the media; iii) after 9 weeks of LFN-exposure, we found new formed vessel presenting tortuous and twisted. There is a significant difference of arterial wall thickness between control and exposed groups. CONCLUSIONS: Deeper layers of gastric wall undergo alterations, including fibrosis of the submucosa caused by collagen IV deposition, an early marker of neoangiogenesis. Vascular alterations included thickening and thrombotic phenomena, but also images of newly formed vessels. This study suggests that, at least in the stomach, LFN-induced fibrosis could be linked with neoangiogenesis.

A study of Al2O3:C films on Si(100) grown by low pressure MOCVD

2002 ◽  
Vol 747 ◽  
Author(s):  
M. P. Singh ◽  
C. S. Thakur ◽  
N. Bhat ◽  
S. A. Shivashankar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
High Frequency ◽  
Aluminium Oxide ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
X Ray ◽  
Transmission Electron ◽  
Current Voltage ◽  
Low Pressure Mocvd

ABSTRACTWe report the characterization of carbonaceous aluminium oxide, Al2O3:C, films grown on Si(100) by metalorganic chemical vapor deposition. The focus is on the study of the effects of carbon on the dielectric properties of aluminium oxide in a qualitative manner. The carbon present in the aluminium oxide film derives from aluminium acetylacetonate used as the source of aluminium. As-grown films comprise nanometer-sized grains of alumina (∼ 20–50 nm) in an amorphous carbonaceous matrix, as examined by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The films are shiny; they are smooth as observed by scanning electron microscopy (SEM). An attempt has been made to explore the defects (viz., oxide charge density) in the aluminium oxide films using room temperature high frequency capacitance – voltage (C-V) and current–voltage (I-V) measurements. The hysteresis and stretch-out in the high frequency C-V plots is indicative of charge trapping. The role of heteroatoms, as characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, in the transport of charge in Al2O3:C films is discussed.

Pulse Plated Amorphous Fe-P Thin Layers for High Frequency Magnetic Applications

2007 ◽  
Vol 537-538 ◽  
pp. 231-238
Author(s):  
Annamaria Mikó ◽  
Márton Takács ◽  
M. Lakatos-Varsányi ◽  
L.K. Varga
Keyword(s):  
Electron Microscopy ◽  
High Frequency ◽  
Thin Layers ◽  
Electrochemical Technique ◽  
X Ray Diffraction ◽  
Frequency Limit ◽  
Amorphous Iron ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetic Applications

Amorphous and partly nanocrystalline amorphous iron-phosphorus (Fe-P) layers have been deposited by pulse electrochemical technique. X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) have been used to characterize the structure in the layers. Depending on the pulse parameters, the structure of Fe-P layers changed from mostly amorphous to partly nanocrystalline amorphous. The magnetic coercivity and the frequency limit of the samples are discussed in terms of the structure of the Fe-P layers. The frequency limit as determined from the permeability spectra is above 10 MHz, which makes these layers suitable for high frequency inductive element applications.

Size of Cd(S,Se) quantum dots in glasses: Correlation between measurements by high‐resolution transmission electron microscopy, small‐angle x‐ray scattering, and low‐frequency inelastic Raman scattering

1993 ◽  
Vol 73 (6) ◽  
pp. 2775-2780 ◽  
Author(s):  
Bernard Champagnon ◽  
Bruno Andrianasolo ◽  
Aline Ramos ◽  
Madeleine Gandais ◽  
Mireille Allais ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
High Resolution ◽  
Raman Scattering ◽  
Small Angle ◽  
Low Frequency ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron

scholarly journals Nanocrystalline 6061 Al Powder Fabricated by Cryogenic Milling and Consolidated via High Frequency Induction Heat Sintering

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Walid Hanna ◽  
Khinlay Maung ◽  
Ehab A. El-Danaf ◽  
Abdulhakim A. Almajid ◽  
Mahmoud S. Soliman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
High Frequency ◽  
Milling Time ◽  
X Ray Diffraction ◽  
Induction Heat ◽  
X Ray ◽  
Cryogenic Milling ◽  
Transmission Electron ◽  
High Frequency Induction

Nanocrystalline 6061 Al alloy was synthesized by cryogenic milling (cryomilling). Both transmission electron microscopy and X-ray diffraction were used to monitor the change in grain size as a function of milling time. The results of both techniques demonstrated a close agreement with respect to two observations: (a) during cryomilling, the grain size of 6061 Al decreased with milling time, and (b) after 15 h of milling, the grain size approached a minimum value of about 22 nm. Despite this agreement, there was a discrepancy: for grain sizes > 40 nm, the grain size measured by transmission electron microscopy was appreciably larger than that inferred from X-ray diffraction. It was shown that powders consolidated via high frequency induction heat sintering (HFIHS) at 500 and 550°C maintained close to nanoscale grain sized microstructure in addition to high compact density in bulk samples. This was manifested by high strength values as compared to microscale grain samples.

Low-frequency noise effects on the rat parotid gland: A transmission electron microscopy study

2017 ◽  
Vol 41 (4) ◽  
pp. 291-295
Author(s):  
Pedro Oliveira ◽  
Goncalo Martins Pereira ◽  
Margarida Seara Simões ◽  
Emanuel Monteiro ◽  
António Pedro Alves de Matos ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Frequency ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Frequency Noise ◽  
Transmission Electron Microscopy Study ◽  
Noise Effects ◽  
Transmission Electron ◽  
Rat Parotid Gland ◽  
Rat Parotid

A study of Al2O3:C films on Si(100) grown by low pressure MOCVD

2002 ◽  
Vol 745 ◽  
Author(s):  
M. P. Singh ◽  
C. S. Thakur ◽  
N. Bhat ◽  
S. A. Shivashankar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
High Frequency ◽  
Aluminium Oxide ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
X Ray ◽  
Transmission Electron ◽  
Current Voltage ◽  
Low Pressure Mocvd

ABSTRACTWe report the characterization of carbonaceous aluminium oxide, Al2O3:C, films grown on Si(100) by metalorganic chemical vapor deposition. The focus is on the study of the effects of carbon on the dielectric properties of aluminium oxide in a qualitative manner. The carbon present in the aluminium oxide film derives from aluminium acetylacetonate used as the source of aluminium. As-grown films comprise nanometer-sized grains of alumina (∼ 20–50 nm) in an amorphous carbonaceous matrix, as examined by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The films are shiny; they are smooth as observed by scanning electron microscopy (SEM). An attempt has been made to explore the defects (viz., oxide charge density) in the aluminium oxide films using room temperature high frequency capacitance – voltage (C-V) and current–voltage (I-V) measurements. The hysteresis and stretch-out in the high frequency C-V plots is indicative of charge trapping. The role of heteroatoms, as characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, in the transport of charge in Al2O3:C films is discussed.

Histological observations of latent infection and tissue colonization by Diaporthe toxica in resistant and susceptible narrow-leafed lupins

1998 ◽  
Vol 76 (7) ◽  
pp. 1305-1316 ◽  
Author(s):  
M Shankar ◽  
W A Cowling ◽  
M W Sweetingham
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Frequency ◽  
Latent Infection ◽  
Epidermal Cells ◽  
Lupinus Angustifolius ◽  
Transmission Electron ◽  
Incompatible Reaction ◽  
Latent Phase

Latent infection and tissue colonization by Diaporthe toxica was examined by light, scanning, and transmission electron microscopy in stems, leaves, and petioles of resistant and susceptible narrow-leafed lupins (Lupinus angustifolius). Resistance was observed during the latent phase of the disease as an incompatible reaction between the host and pathogen that appeared to occur after penetration of the cuticle. Conidia were attached firmly to the cuticle by an extracellular substance presumably exuded from the conidia. Conidia penetrated the cuticle directly via an infection peg and formed subcuticular coralloid hyphae. The frequency of subcuticular coralloid hyphae was similar on stems, leaves, and petioles of each line. At 14 days after inoculation, resistant plants had a high frequency of small coralloid hyphae (10-80 µm length). The epidermal cells beneath these small coralloid hyphae appeared necrotic and collapsed with accumulation of polyphenolics and electron-dense substances and a loss of internal organisation in the cytoplasm. Necrosis was occasionally observed in small coralloid hyphae as well. Susceptible plants had a high frequency of large coralloid hyphae (80-400 µm length) in which intrahyphal hyphae were observed, and host epidermal cells beneath large coralloid hyphae appeared normal. Colonization of tissues below the cuticle began immediately after excision of stems from susceptible plants, but was delayed in resistant plants. At 8 days after excision, hyphae had invaded all stem tissues and initiated the formation of pycnidia in susceptible plants, but few hyphae were observed in stems of resistant plants.Key words: Diaporthe toxica, coralloid hyphae, Lupinus angustifolius, resistance.

On the GHz Frequency Response in Nanocrystalline FeXN Ultra-Soft Magnetic Films

2002 ◽  
Vol 720 ◽  
Author(s):  
N.G. Chechenin ◽  
C.B. Craus ◽  
A.R. Chezan ◽  
T. Vystavel ◽  
D.O. Boerma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Frequency Response ◽  
High Frequency ◽  
Strong Dependence ◽  
Magnetic Films ◽  
Soft Magnetic ◽  
High Frequency Response ◽  
Lifshitz Equation ◽  
Transmission Electron ◽  
Lorentz Transmission Electron Microscopy

AbstractThe periodicity and angular spread of the in-plane magnetization for ultrasoft nanocrystalline FeZrN films were estimated from an analysis of the ripple structure, observed in Lorentz transmission electron microscopy (LTEM) images. The influence of the micromagnetic ripple on the ferromagnetic resonance (FMR) width is analyzed using an approach based on the Landau-Lifshitz equation. A strong dependence of the resonance width on the magnetic moment dispersion is predicted. To a large extent this particular aspect explains the high frequency response in some of our films.

Plasma Cleaning and Its Applications for Electron Microscopy

1999 ◽  
Vol 5 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Thomas C. Isabell ◽  
Paul E. Fischione ◽  
Catherine O'Keefe ◽  
Murat U. Guruz ◽  
Vinayak P. Dravid
Keyword(s):  
Electron Microscopy ◽  
High Frequency ◽  
Analytical Techniques ◽  
Low Energy ◽  
Hydrocarbon Contamination ◽  
Plasma Cleaning ◽  
Tem Analysis ◽  
Gas Plasma ◽  
Transmission Electron ◽  
Reactive Gas

The effectiveness of applying a high-frequency, low-energy, reactive gas plasma for the removal of hydrocarbon contamination from specimens and components for electron microscopy has been investigated with a variety of analytical techniques. Transmission electron microscopy (TEM) analysis of specimens that have been plasma cleaned shows an elimination of the carbonaceous contamination from the specimen. With extended cleaning times the removal of existing carbon contamination debris due to previously conducted microanalysis is shown. Following plasma cleaning, specimens may be examined in the electron microscope for several hours without exhibiting evidence of recontamination. The effectiveness of plasma cleaning is not limited to applications for TEM specimens. Scanning electron microscopy (SEM) specimens that have been plasma cleaned likewise show an elimination of carbonaceous contamination. Furthermore, other electron microscopy parts and accessories, such as aperture strips, specimen clamping rings, and Wehnelts, among others, can benefit from plasma cleaning.

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