Microscopic examination of the deep donor EL2 in undoped semi-insulating GaAs

Microscopic Examination of EL2 Associated with Single Dislocations in GaAs

MRS Proceedings ◽

10.1557/proc-46-213 ◽

1985 ◽

Vol 46 ◽

Author(s):

D.J. Stirland ◽

M.R. Brozel

Keyword(s):

Dislocation Density ◽

Microscopic Examination ◽

Donor Level ◽

Infrared Transmission ◽

Transmission Microscopy ◽

Low Dislocation Density ◽

Infra Red ◽

Deep Donor ◽

Deep Donor Level

Abstract2" diameter wafers cut from indium doped, liquid encapsulated Czochralski (LEC) grown GaAs ingots have been examined by two different methods. Dislocations were revealed by etching, and isolated regions of enhanced [EL2], the concentration of the deep donor level EL2, weredetected by infrared transmission microscopy. In regions of low dislocation density (∼5 × 102 cm−2) single isolated dislocations were identified and at the identical sites infra-red micrographs showed increased absorption. The results demonstrate that enhancement of [EL2]occurs at single dislocations, and that the enhancement can be detected by suitable etching techniques.

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Properties of Isolated Mitochondria of Agaricus Bisporus: Their Relationship to Dormancy and the Germination of Spores

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072733 ◽

1973 ◽

Vol 31 ◽

pp. 458-459

Author(s):

K. S. McCarty ◽

R. F. Weave ◽

L. Kemper ◽

F. S. Vogel

Keyword(s):

Mitochondrial Dna ◽

Ethidium Bromide ◽

Microscopic Examination ◽

Agaricus Bisporus ◽

Osmotic Shock ◽

Electron Microscopic Examination ◽

Electron Microscopic ◽

Isolated Mitochondria ◽

Dna Strands ◽

Cytoplasmic Ribosomes

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.

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Artifact-free electron microscopic immunocytochemistry on rat brain tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085666 ◽

1991 ◽

Vol 49 ◽

pp. 272-273

Author(s):

Veronika Burmeister ◽

N. Ludvig ◽

P.C. Jobe

Keyword(s):

Microscopic Examination ◽

Free Electron ◽

Electron Microscopic Examination ◽

Ultrastructural Localization ◽

Rabbit Serum ◽

Electron Microscopic ◽

Electron Microscopic Immunocytochemistry ◽

Phosphate Buffered Saline ◽

Rat Brain Tissue ◽

Immune Rabbit

Electron microscopic immunocytochemistry provides an important tool to determine the ultrastructural distribution of various molecules in both normal and pathologic tissues. However, the specific immunostaining may be obscured by artifactual immunoreaction product, misleading the investigator. Previous observations show that shortening the incubation period with the primary antibody from the generally used 12-24 hours to 1 hour substantially reduces the artifactual immunostaining. We now extend this finding by the demonstration of artifact-free ultrastructural localization of the Ca2/calmodulindependent cyclic nucleotide phosphodiesterase (CaM-dependent PDE) immunoreactivity in brain.Anesthetized rats were perfused transcardially with phosphate-buffered saline followed by a fixative containing paraformaldehyde (4%) and glutaraldehyde (0.25%) in PBS. The brains were removed, and 40μm sections were cut with a vibratome. The sections were processed for immunocytochemistry as described by Ludvig et al. Both non-immune rabbit serum and specific CaM-dependent PDE antibodies were used. In both experiments incubations were at one hour and overnight. The immunostained sections were processed for electron microscopic examination.

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Ineffective Thrombopoiesis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158881 ◽

1990 ◽

Vol 48 (3) ◽

pp. 266-267

Author(s):

JM Radley ◽

SL Ellis

Keyword(s):

Microscopic Examination ◽

Phosphate Buffer ◽

Primary Myelofibrosis ◽

Transient Increase ◽

Major Difficulty ◽

Adult Mice ◽

Dense Cytoplasm

In effective thrombopoies is has been inferred to occur in several disease sates from considerations of megakaryocyte mass and platelet kinetics. Microscopic examination has demonstrated increased numbers of megakaryocytes, with a typical forms particularly pronounced, in primary myelofibrosis. It has not been documented if megakaryocyte ever fail to reach maturity in non-pathological situations. A major difficulty of establishing this is that the number of megakaryocytes normally present in the marrow is extremely low. A large transient increase in megakaryocytopoiesis can how ever be induced in mice by an injection of 5-fluorouracil. We have utilised this treatment and report here evidence for in effective thrombopoies is in healthy mice.Adult mice were perfused (2% glutaraldehyde in 0.08M phosphate buffer, pH 7.4) 8 days following an injection of 5-fluorouracil (150mg/kg). Femurs were subsequently decalcified in 10% neutral E.D.T.A. and embedded in Spurrs resin. Transverse sections of marrow revealed many megakaryocytes at various stages of maturity. Occasional megakaryocytes (less than 1%) were found to be under going degeneration prior to achieving full maturation and releasing cytoplasm as platelets. These cells were characterized by a peripheral rim of dense cytoplasm which enveloped a mass of organelles and vacuoles (Fig. 1). Numerous microtubules were foundaround and with in the organelle-rich zone (Fig 2).

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