bluuebunny/crossref_metadata_2025 huggingface dataset:
The Use of an Array Processor for Calculation of High Resolution
Images
Authors: Rez P.
Published: June 2020

Computer simulation of high resolution images is often necessary to
determine the effects of different model structures on the image and to
check that images show the correct behaviour with defocus.

To calculate the image of a defect, periodic continuation must be
used.1,2 The scattering from the defect is then
sampled by a large number of beams and a slice method is optimal for
calculating these Images. The multislice method has proven to be popular for
these applications and the algorithm for generating the beam amplitudes at t
+ Δt is 3
Elemental Distribution in Pt-Re:Al2O3 Naphtha
Reforming Catalysts
Authors: Freed R. L. , Kelley M. J.
Published: June 2020

The commercial introduction of Pt-Re supported catalysts to replace Pt
alone on Al2O3 has brought
improvements to naphtha reforming. The bimetallic catalyst can be operated
continuously under conditions which lead to deactivation of the single metal
catalyst by coke formation. Much disagreement still exists as to the exact
nature of the bimetallic catalyst at a microscopic level and how it
functions in the process so successfully. The overall purpose of this study
was to develop the materials characterization tools necessary to study
supported catalysts. Specifically with the
Pt-Re:Al2O3 catalyst, we
sought to elucidate the elemental distribution on the catalyst.
Cold Stage Scanning Electron Microscopy of Bentonite Suspensions
Authors: Jenekhe S. A. , Davis H. T. , Scriven L. E.
Published: June 2020

Aqueous suspensions of clay mineral particles evidently form gels owing
to interactions between the electrically charged particles. It is generally
accepted that physical properties of a suspension, especially rheological
properties, reflect its microstructure and that deformation brings about
structural changes (1) We have applied fast-freeze cold-stage scanning
electron microscopy to visualize the microstructures of bentonite clay
suspensions of known shear history.
Analytical Electron Microscopy of (W,Ti)C
Authors: Shinde Subhash L.
Published: June 2020

Addition of titanium to tungsten carbide changes its structure from
hexagonal to NaCl type in the single phase region of the W-Ti-C ternary.
This results in a change of the slip systems active during deformation. It
Is thus possible to improve the mechanical properties of WC (especially
toughness) by the alloying addition of Ti. The purpose of this study is to
identify the appropriate deformation mechanisms, using TEM
techniques.

The present report deals with investigations on deformed and undeformed
single phase ternary carbides. The bulk (W,Ti)C samples were obtained by arc
melting presintered pellets of mechanically mixed WC and TiC powders with a
nominal composition of 22.5% W, 32.5% Ti, and 45% C (atomic). Three
millimeter dia. discs of 100 μm thickness were obtained from these samples
by spark cutting and further mechanical grinding. The deformation was
introduced by creating a square array of micro-indentations. The discs were
then ion-beam thinned.
The Characterization of Coal Structures for Coal Gasification Reactions
Using Tem/Stem Techniques
Authors: Little J. A. , Evans J. W. , Westmacott K. H.
Published: June 2020

The liquefaction and gasification of various coals are increasingly
important technological utilizations of coal which are dependent upon its
physical characteristics as well as its chemistry. In this respect, both the
size and distribution of pores and the size, distribution and chemical
identity of the submicron size minerals are physical parameters of great
interest because of their probable influence in the coal conversion
processes. In Berkeley, this study is proceeding by examination of such
processes using an environmental cell in a high voltage microscope, by which
the influence of different gases, temperatures and pressure upon the
gasification reaction can be studied. An important first step in such a
study is the primary characterization of the coals to be studied and the
combined use of both transmission (TEM) and scanning transmission electron
microscope (STEM) analyses utilizing both convergent beam methods and an
energy dispersive X-ray analytical detector is thus a powerful tool in such
a characterization.
Collection and Analysis of Sem and Tem Data Using a Random Access Video
Frame Store
Authors: Harland C.J. , Venables J. A.
Published: June 2020

We have investigated the possibility of using a large random access
video frame store (VFS) for the collection, storage and analysis of SEM and
TEM data. Here we describe how such a store can be used to enhance the
microanalytical facilities in our laboratory, and we show some preliminary
results to demonstrate its power.

A block diagram of the proposed system is shown in fig. 1. The store is
arranged so that data can be collected, displayed and randomly accessed by
the computer, all independently and asynchronously. The VFS can be addressed
either from an external source or addressing can be software generated, with
the computer also controlling the source timing. The computer has access to
any part of the VFS and can thus remove, modify and replace any stored data
at any time allowing simple processing routines to be performed in
real-time, or more complex operations on 'frozen' images. Standard computer
peripherals are used for operator interaction for program storeage and for
hard-copy recording of graphs and numerical data. Synchronous read and write
operations on the VFS allow noise-reduction of TV rate images by
time-averaging or recursive filtering. This is of particular advantage over
long lime-constant SEM and SAM imaging as it enables one to observe the
image continuosly while greatly reducing the effects of 1/f noise.
Asynchronous operations enable the VFS to be used for scan-conversion of SEM
slow-scan inputs into good quality TV rate images for display and video
recording.
Factors in Photographic Emulsions for Low Dose Electron
Crystallography
Authors: Jeng T.W. , Chiu W.
Published: June 2020

With the advances in preparing biological materials in a thin and highly
ordered form, and in maintaining them hydrated under vacuum, electron
crystallography has become an important tool for biological structure
investigation at high resolution (1,2). However, the electron radiation
damage would limit the capability of recording reflections with low
intensities in an electron diffraction pattern. It has been demonstrated
that the use of a low temperature stage can reduce the radiation damage
effect and that one can expose the specimen with a higher dose in order to
increase the signal contrast (3). A further improvement can be made by
selecting a proper photographic emulsion. The primary factors in evaluating
the suitability of photographic emulsion for recording low dose diffraction
patterns are speed, fog level, electron response at low electron exposure,
linearity, and usable range of exposure. We have compared these factors with
three photographic emulsions including Kodak electron microscopic plate
(EMP), Industrex AA x-ray film (AA x-ray) and Kodak nuclear track film
(NTB3).
Coiled Construction of Exinous Units in Pollen of Artemisia
Authors: Rowley John R. , Orville Dahl A. , Rowley Joanne S.
Published: June 2020

We find the pollen grain exine of Artemisia
vulgaris to be composed of units 60-100nm in diameter,
consisting of helical subunits about 10nm in diameter. Ontogenetically the
unit originates at the plasma membrane as a rod-shaped complex of glycocalyx
elements, which we call a tuft (1). During
development subunits of the exine become embedded within the polymer,
sporo-pollenin, and thereafter exines appear amorphous in sections.
Assessment of The Effects of Sulfur Dioxide (SO2) on Lichens
Using Energy Dispersive X-Ray Spectroscopy
Authors: Swafford J. R. , Moser T. J.
Published: June 2020

Lichens which are ubiquitous plants composed of a symbiont fungus and
alga have been known for years to be sensitive bioindicators of air
pollutants. Their presence has been used as an index of atmospheric purity.
It is thought that sulfur dioxide (SO2) is the prime
cause for the disappearance of lichens from urban areas (a lichen desert).
Air quality can be monitored by observing the deterioration of lichen flora
by their ability to absorb pollutants efficiently. Although certain
pollutant-sensitive species do not readily demonstrate macroscopic changes
in early stress situations, monitoring of photosynthetic capabilities and
chlorophyll content have been used as a measure of subtle metabolic changes.
Concomitant with a reduction in photosynthesis, an intracellular loss of
potassium (K+) has been noted.
Theoretical And Practical Design Considerations for Ultra-High Resolution
Electron Lenses
Authors: Harada Y. , Tsuno K. , Arai Y.
Published: June 2020

Magnetic objective lenses, from the point of view of pole piece
geometry, can he roughly classified into two types, viz., symmetrical and
asymmetrical. In the case of the former, the optical properties have been
calculated by several authors1-3) and the results would
appear to suggest that, in order to reduce the spherical and chromatic
aberration coefficients, Cs and Cc, it is necessary to decrease the
half-width value of the axial field distribution and to increase the peak
flux density. The expressions for either minimum Cs or minimum Cc were
presented in the form of ‘universal’ curves by Mulvey and
Wallington4).
Spiral Distortion in Electron Mtcroscopy During Use of Three-Pole-Piece
Lens
Authors: Tsuno K. , Ishida Y. , Harada Y.
Published: June 2020

A projector lens with three pole pieces and double gaps of opposite
excitation (three-pole-piece lens) has some advantages. There include 1),
Rotation-free images can be obtained even if the lens excitation is
changed1; 2) , Radial
distortion1 is reduced to zero at an excitation of
minimum focal length. However, spiral distortion was not
reduced1. We investigated spiral distortion of a
three-pole-piece lens by changing the lens dimension in order to find a lens
shape that resulted in zero spiral distortion in electron
microscopy.
Tem Studies of Laser Pulse-Annealed Silicon
Authors: Cullis A.G.
Published: June 2020

The evolution of semiconductor technology depends for its impetus upon
continuing advances in materials processing. Over the past few years
particularly dramatic advances have been made in the area of the pulsed
annealing of semiconductors. The present article will be concerned with the
use of Q-switched laser radiation for Si annealing - a technique which has
received in-depth study?.1-4 As will be shown below,
transmission electron microscope (TEM) analysis of annealed samples can give
detailed information about the annealing mechanism and its associated
characteristic phenomena.
The Crystallization Behavior of The Metglas Alloy
2826MB(Fe38Ni40Mo4B18)
Authors: Mizgalski K. , Inal O.T. , Murr L.E. , Yost F.
Published: June 2020

We have detected a Si hexagonal phase in wafers implanted at high dose
rate, P-type, 2-12 Ωcm, <001> oriented Si wafers were implanted by 80
keV As+ ions to a dose of
1016/cm2 at a current of 100
μA. These samples, without further heat treatment, were analyzed by TEM
observations. The hex Si appears as a few hundred Å long rods elongated in
the matrix <110> direction, see Fig. 1. They produce weak but
observable diffraction effects which led to their identification, Fig. 2.
The orientation relationship of the hex and dc Si is that
[000l]hex | | [110]dc and
[1010]hex | | [001]dc. Because
of their small sizes, we could not identify their habit planes. Mechanical
deformation experiments, however, showed that large size hex Si platelets
with {115}dc habit planes may be
produced.3 We have performed such experiments to
confirm this point. We now propose a dc to hex phase transformation scheme
for Si. Assume that the transformation driving force is a large compressive
stress in the dc [110] direction. Then the bond between an atom and one of
its two nearest neighbors on the (110) plane may be broken and a new bond
between this atom and one of its two second nearest neighbors along the
[110] direction may be formed. In this way, six membered atomic rings
appropriate for the hex type structure are formed, Fig. 3(a). Relaxation of
these new rings proceeds simultaneously to give the structure in Fig. 3(b),
which is the hex Si structure with proper orientation relationship w.r.t. dc
Si. After the transformation, the material expanded by ~18% in the
[110]dc direction, contracted by ~18% in the
[110]dc direction. Thus, the transformation
facilitates a stress relieving mechanism which provided a relief of the
equivalent of ~18% of a pure elastic compression in the dc
[110]dc direction. We estimated that the hex Si is
~1011 ergs/cm3 higher in
energy than the dc Si, and an activation energy of
~1011 ergs/cm3 is needed to
induce this transformation. We have also constructed an atomic model for the
dc-hex Si interface, the (115) habit plane. This interface is composed of
5-7 membered atomic rings with no dangling bonds or long range strains and
it is therefore a low energy configuration, Fig. 4. Hexagonal Si were
generated in ion implanted samples, we believe, because of direct transfer
of momentum from the the impinging ions provided enough energy to overcome
the nucleation barrier. Once they are generated, stress provided by
dislocations and amorphous zones stabilized the transformed
regions.
Interfacial Solute Segregation Observed Using X-Ray Microanalysis in the
TEM/STEM
Authors: Williams D. B.
Published: June 2020

Solute segregation occurring at grain boundaries or interphase
interfaces can take the form of Gibbsian (equilibrium) segregation or
segregation associated with phase transformations occurring at the
interface. Gibbsian segregation results in monolayer level segregation and
has been associated with the cause of temper embrittlement in metals and the
formation of thin amorphous grain boundary films in powder-compacted
ceramics. To date the most successful technique for its study has been Auger
electron spectroscopy (AES) which possesses the necessary surface resolution
but has the specific drawbacks of UHV operation, the need for intergranular
fracture in-situ and poor image resolution. Solute segregation associated
with grain boundary and interphase interface phase transformations
occasionally occurs over distances > 1 μm and hence is detectable by
conventional electron microprobe microanalysis. However the properties of
alloys are more often than not governed by sub-micron precipitation and
associated composition profiles. To date quantitative microanalysis of such
phenomena has only been achieved using plasmon energy loss
microanalysis(1) which unfortunately is only
applicable to low Z alloys such as Al and Mg base with well defined plasmon
loss spectra.
Mc Precipitate Characterization in Austenitic Stainless Steel
Authors: Maziasz P. J. , Carpenter R. W.
Published: June 2020

MC precipitate particles in austenitic stainless steels have an
important and unique effect on radiation response of these materials in a
fusion reactor environment.Radiation-generated helium agglomerates at the
precipitate/matrix interfaces in the form of small bubbles. There are two
morphological variants of the precipitate and both have similar helium
trapping behavior. In this note we describe initial observations of one
crystallographic and morphological variant of MC in austenite, which is the
dominant variant formed during neutron irradiation in HFIR.
Yielding and Plastic Flow in Stainless Steel: A TEM Study of the
Evolution of Microstructure Associated with the Stress-Strain
Diagram
Authors: Murr L.E. , Wang S-H.
Published: June 2020

In spite of the fascination with dislocation pile-ups and the
description of flow in metals and alloys based upon pile-up models, evidence
has existed for decades suggesting that slip often if not always starts at
grain boundaries in polycrystalline metals and alloys. Hook and Hirth showed
that elastic incompatibility could result in local slip at the boundary
between bicrystals, and their contention that local elastic stress
concentrations at grain boundaries would aid slip nucleation was confirmed
by Carrington, etal. Ashby has also described polycrystalline metals and
alloys as plastically non-homogeneous because gradients of plastic
deformation are imposed by the grain boundaries, and Murr has discussed the
role of grain boundary ledges as initial sources for dislocations when
polycrystalline metals and alloys are deformed. Brentnall and Rostoker
earlier concluded that grain boundaries are both sources of early
dislocations and barriers limiting their movement at higher stresses, and
that slip is confined to grains in which it was initiated until the yield
point is reached.
Analysis of Sputtered Zinc Oxide Films
Authors: Emma T. A. , Singh M. P.
Published: June 2020

Optical quality zinc oxide films have been characterized using
reflection electron diffraction (RED), replication electron microscopy
(REM), scanning electron microscopy (SEM), and X-ray diffraction (XRD).
Significant microstructural differences were observed between rf sputtered
films and planar magnetron rf sputtered films.

Piezoelectric materials have been attractive for applications to
integrated optics since they provide an active medium for signal processing.
Among the desirable physical characteristics of sputtered ZnO films used for
this and related applications are a highly preferred crystallographic
texture and relatively smooth surfaces. It has been found that these
characteristics are very sensitive to the type and condition of the
substrate and to the several sputtering parameters: target, rf power, gas
composition and substrate temperature.
The Actin Lattice: Composition, Structure and Membrane Attachment
Authors: Condeelis J. , Wolosewick J.
Published: June 2020

Actin containing structures in the cytoplasm of non-muscle cells have
been implicated in cell locomotion and control of the distribution of
cytoplasmic and cell surface components. Consistent with this versatility of
actin function is the complexity of actin containing structures that are
found in non-muscle cells.

Actin is a highly conserved protein with identical functional properties
from cell to cell. Recently a number of actin binding proteins have been
purified that may account for the assembly of actin into the different
structures found in vivo. We have been investigating the actin binding
proteins that are responsible for Ca++ regulated gelation of actin that was
first documented in cell free extracts of Dictyostelium discoideum, a
cellular slime mold. In this case these actin binding proteins will be
referred to as gelation factors. Our method for purifying the gelation
factors from Dictyostelium is briefly outlined as follows. Cell free
extracts that contained gelation activity were fractionated with ammonium
sulfate into O-45 and 45-60% pellets. Gelation activity in each pellet was
purified by chromatography. The 45-60% pellet contained 95% of the gelation
activity in the extract and was resolved into two gelation factors that
measure 250,000 daltons and 120,000 daltons in SDS (Figure 1 b and d
respectively). The remaining 5? of the gelation activity that was collected
in the 0-40% pellet was recovered with a complex of 5 low molecular weight
components that measure 48,000, 38,000, 32,000, 24,000 and 20,000 daltons in
SDS (Figure le). The polypeptides appear to be proteolytic breakdown
products of higher molecular weight gelation factors since their presence in
the extract was abolished by inclusion of proteolytic inhibtors.
Analytical Electron Microscopy Identification of Zirconium Induced
Granuloma
Authors: Mehard C.W. , Epstein W.L.
Published: June 2020

Contact with certain organic zirconates or inorganic zirconium salts may
induce granuloma in the skin. Zirconium (element No. 40) is used in a number
of industrial applications and therefore may present health haz-zards either
during industrial preparation or upon exposure to the product.

Clinical identification of the causative agent of a skin granuloma in
general is a difficult task without a proper history of the patient and in
some instances may be virtually impossible if the patient is contaminated
unknowingly. Conventional clinical microscopy evaluation of skin biopsies
does not reveal the elemental content of granular inclusions of cells.
Qualitative elemental analysis of a diseased tissue by techniques such as
atomic absorption, mass spectroscopy or wet chemical methods may be used to
determine the composition if there is sufficient biopsy material. Element
identification of an unknown or presumed causative agent by analytical
electron microscopy (AEM), i.e. STEM-EDS, of a single cell or cell
organelle, in amounts that are orders of magnitude smaller than required for
the other analytical techniques, makes this technique more applicable for
diagnostic evaluations of biopsy specimens.
Fine Structural Changes in the Ca2+, Ca2+ and
Mg2+–Activated ATPase, and Alkaline Phosphatases in Renal
Tubules after Cisplatin Treatment
Authors: Aggarwal S.K. , Hammouda E.M.
Published: June 2020

Cisplatin is increasingly being used clinically as a broad spectrum
antitumor agent. Recently it has been approved by the U.S. Department of
Food and Drug Administration for use against the ovarian and testicular
tumors. However, the drug is not without its side effects like kidney
toxicity, neurotoxicity, intestinal toxicity and toxicity to the
hematopoetic organs. The nephrotoxicity is still the major concern of the
clinicians. Possible means of amelioration of these toxic side effects are
presently under active investigation and the knowledge of the mode of action
of this drug at the cellular level would be of immense significance. Our
previous biochemical studies have demonstrated an effect of cisplatin on the
uncoupling of the oxidative phosphorylation, causing an efflux of the
Ca2+ from the isolated liver or kidney mitochondria
and an inactivation of ATPase as measured by Pi release.
Heptatic Response to Hyperthermia
Authors: Bowers W. D. , Hubbard R. , Chisholm P. , Murphy M. , Williams P.
Published: June 2020

Pettigrew et al. (1) proposed that above 41.8° C normal cells were
subject to hyperthermic injury while at or below this temperature no serious
cellular injury occurred. Cancer patients were maintained at this
temperature for several hours, with little evidence of injury, in efforts to
kill the more heat sensitive cancer cells. Inherent in this treatment regime
was the theory that the duration of hyperthermic treatment at or below
41.8°C had no impact on injury to normal cells. Previous work in our
laboratory, using the time course of enzyme leakage from isolated rat livers
perfused with KRB at 37° C-43° C for 90 min, suggested that injury followed
a time/temperature relationship. Ultrastructural, histological, and
enzymatic data indicated that injury could occur below 41.8°C. Electron
microscopy revealed celluar injury in livers which appeared normal by light
microscopy. The time at which ultrastructural changes occurred at specific
temperatures could not be determined since specimens were taken at the end
of the perfusion experiments. In this study, livers were perfused for varing
time intervals at temperatures from 41° C to 43° C, and these were compared
with control livers perfused at 37° C for 90 min. The liver was chosen for
this study because it is a common site of injury in both heatstroke and
hyperthermic therapy. In addition, perfusion allows precise control of the
organ's environment.
Unusual Cytoplasmic Inclusion Bodies in Medullary Carcinoma of the
Thyroid
Authors: Kakudo K. , Spurlock B. O. , Miyauchi A. , Kuma K. , Shimaoka K.
Published: June 2020

Medullary Thyroid Carcinoma(MTC) was first described by Hazard et al.
and it is known to be C-cell origin and one of the members of APUDomas.
Recently we have studied ultrastructural characteristics of 17 cases of MTC
and this report describesultrastructural features of an unusual case in
which 4 types of cytoplasmic inclusions other than typical secretory
granules and ordinary cytoplasmic organelle were observed. The clinical and
histologic features of this case were typical of the MTC and the patient was
treated with Co radiation 90 days prior to the surgery.

Small pieces of the tumor tissues(lymph node metastasis) obtained from
43 year-old male patient at total thyroidectomy and left modified neck
disection were prepared for transmission electron microscopy by standard
methods.
TEM and SEM Studies on Alteration of Collagen Fibrils in the Inguinal
Herniation
Authors: Sun C. N. , White H. J. , Read R. C , Watson J. H. L.
Published: June 2020

Although a large number of conditions in man and animals has been
designated as collagen diseases, there is as yet no conclusive evidence to
prove collagen involvement in most of these conditions. In a study of
patients undergoing inguinal herniorrhaphy, the anterior rectus sheath some
inches above the defect was noted to be thinner than normal, especially in
those with the direct type. This observation was confirmed by weighing
samples of constant area. Further study revealed that the lighter weight of
rectus sheath biopsies from adults with inguinal herniation could be
accounted for by a striking decrease in hydroxyproline. The content of
hydroxyproline in the direct inguinal herniation as measured in terms of
tissue dry weight was lower and the amount of proline in the direct hernia
specimens was significantly higher, thus accounting for a significantly
lower ratio of hydroxyproline:proline compared to control or indirect hernia
samples.
Bluetongue Virus Association with Fibrils and Macrotubules in Cultured
Cells
Authors: Breckon Ruth D. , Foster Neil M.
Published: June 2020

Filaments and tubules have been observed1-4 in
association with viroplasms and progeny particles in bluetongue virus
(BTV)-infected cells. Clusters of virions often had fine filaments attached
to the particle core with possible connections between
filaments.2 Macrotubules had diameters of 45-50
nm2,5,6 when observed in thin section and
approximated the diameter of the BTV core particle of 50-55
nm.4 Macrotubules often contained dark-staining
centers that were similar in size to the inside diameters of the tubules (35
nm) and to the dark-staining BTV RNA cores (30 nm).6
This report further describes the fibrils (filaments) and tubules in
BTV-infected cells.
Fibrils, Tubules, and Crystals in Cells Infected with Epizootic
Hemorrhagic Disease Virus
Authors: Breckon Ruth D. , Foster Neil M.
Published: June 2020

Epizootic hemorrhagic disease virus (EHDV), an orbivirus taxonomically
and an arbovirus epidemiologically, replicated in cytoplasmic matrixes of
infected cells.1-3 Filaments and macrotubules were
observed in the cytoplasm and in association with viroplasms in
EHDV-infected cells.1-3 In two
studies,2,3 the diameters of the macrotubules were
similar to that of the virion, i.e., 53 and 62 nm. One
study1 reported that the outer and inner diameters
of macrotubules were 40-50 and 35-40 nm and the diameter of the virions was
59 nm with an electron-dense core of 40 nm. Another
report4 gave macrotubule outer and inner diameters
of ca 35 and 25 nm and a virus diameter of ca 60 nm with an RNA core of 30
nm. Many tubules contained dark-staining centers similar in diameters to
that of the interiors of the macrotubules and the EHDV RNA
cores.4 This report describes additional
morphological features associated with EHDV-infected cells.
Cytopathology of Tissues from Chicken Embryos Infected with Venezuelan
Equine Encephalomyelitis Virus
Authors: Foster Neil M. , Alders Marjorie A.
Published: June 2020

The morphology and morphogenesis of Venezuelan equine encephalomyelitis
(VEE) virus in cultured cells and suckling mouse brains have been
described.1-3 Briefly, VEE virus entered cells by
viropexis and was uncoated; the virus RNA induced virus-specific synthesis
which resulted in viroplasms where nucleoids were formed. Virions were
formed by nucleoids that budded through plasma or cytoplasmic organelle
membranes.

Ten to 11-day-old embryonating chicken eggs were inoculated with VEE
virus (TC-83 vaccine strain) and incubated until the embryos showed terminal
stages of the disease at 19 hours after infection. Liver, lung, heart,
kidney, and skin samples from the embryos were processed for viewing in thin
section.4
Scanning and Transmission Microscopy of Microbial Flora Adherent to
Colonic Polyps
Authors: Edmiston C.E. , Goheen M. , Allen S.D. , Wilson F.A.
Published: June 2020

Fiberoptic colonoscopy was used to obtain mucosal biopsies of colonic
polyps and normal mucosa for the purpose of studying microbial ecology and
mucosal adherence in vivo. These studies involved the taking of multiple
mucosal biopsies throughout the length of the large bowel, specifically
biopsies of colonic polyps (adenomatous and hyperplastic) and the areas
immediately adjacent to them. Earlier observations have documented the
feasibility of this technique for studying microbial populations in
situ1. The mucosal samples were evaluated by
quantitative bacteriology, transmission microscopy and scanning electron
microscopy. The colonic mucosal biopsies obtained during routine colonoscopy
were immediately prefixed in 3% glutaraldehyde buffered in 0.1M sodium
cacodylate. Those specimens for TEM were postfixed in 1% osmium, dehydrated
and embedded in Epon. Biopsies for SEM were prepared according to the OTO
method described by Kelley2. Specimens for TEM were
observed in a Phillips 300 at 80KV, while specimens for SEM were processed
in a Phillips 500 at 25KV with a spot size of 80Å.
Ultrastructure of Mitosis in the Aquatic Phycomycete Chytriomyces
Hyalinus
Authors: Pechak David G.
Published: June 2020

The aquatic Phycomycetes, particularly the Chytridiales, are a group of
fungi with a rather simple life cycle and morphology. With the advent of
ultrastructural investigations on these organisms, two stable
characteristics (zoospore ultrastructure and nuclear division) have proven
helpful in elucidating relationships in this perplexing taxon. The latter is
described in this communication. Conventional techniques were employed in
the preparation of the material.

Interphase nuclei of C. hyalinus are essentially spherical in shape,
measure approximately 2.8 μm in diameter, and have a single, centrally
located, nucleus. Prophase nuclei, while not exhibiting condensed chromatin,
are characterized by the presence of migrating centrioles and a fusiform or
spindle-shape to the nuclear profile (Fig. 1). Nuclear pores predominate
near the polar ends of the nuclear envelope. No evidence has been found to
indicate that centrioles replicate during prophase.
Immunoferritin Labelling of Murine Leukemia Virus Antigens in thin
Sections
Authors: Weigand Ray A. , Varjabedian Gregory C.
Published: June 2020

We previously described the intracellular localization of murine mammary
tumor virus (MuMTV) p28 protein in thin sections (1). In that study, MuMTV
containing cells fixed in 3% paraformaldehyde plus 0.05% glutaraldehyde were
labelled after thin sectioning using ferritin-antiferritin in an unlabelled
antibody technique. We now describe the labelling of murine leukemia virus
(MuLV) particles using the unlabelled antibody technique coupled to
ferritin-Fab antiferritin.

Cultures of R-MuLV in NIH/3T3 cells were grown to 90% confluence (2),
fixed with 2% paraformaldehyde plus 0.5% glutaraldehyde in 0.1 M cacodylate
at pH 7.2, postfixed with buffered 17 OsO4, dehydrated
with a series of etha-nols, and embedded in Epon. Thin sections were
collected on nickel grids, incubated in 107
H2O2, rinsed in HEPES buffered
saline, and subjected to the immunoferritin labelling procedure. The
procedure included preincubation in 27 egg albumin, a four hour incubation
in goat antisera against purified gp69/71 of MuLV (3) (primary antibody),
incubation in F(ab’)2 fragments of rabbit antisera to
goat IgG (secondary antibody), incubation in apoferritin, incubation in
ferritin-Fab ferritin, and a brief fixation with 2% glutaraldehyde. The
sections were stained with uranyl acetate and examined in a Siemens IA
electron microscope at an accelerating voltage of 60 KV.
Early Events in Virus Budding: Murine Leukemia Virus Envelope
Glycoprotein-Core Protein Organization at the Cell Surface
Authors: Demsey A.
Published: June 2020

Structurally, the murine leukemia virus consists of a core, which forms
at the cell surface membrane, and an envelope, composed principally of host
lipid and virus-specified glycoprotein, which is acquired as the core
emerges through the cell membrane during budding. The core is composed of
four proteins (p30, p15, p12, and p10), initially translated as part of
larger precursor polypeptides, whereas the major virus surface glycoprotein,
gp70, is initially part of a separate precursor, also containing a 15000 MW
moiety (pl5E) which is highly hydrophobic and thought to be embedded within
the membrane. Our present work is directed toward determining some of the
associations which exist between these molecules just prior to, and at the
onset of budding.

We have previously demonstrated that the onset of the budding process is
marked on the cell surface by the aggregation of 10nm particles (knobs) into
small clusters (1). These knobs have been shown to consist of approximately
three gp70 molecules, and to be dispersed on the generalized cell surface
prior to budding (2, 3). As the budding process continues, the virus surface
becomes increasingly covered with knobs, while the core components
simultaneously aggregate at the subjacent cytoplasmic surface. We have
verified the transmembrane associations of these viral components prior to
budding by antibody-mediated ferritin labelings of the cell surface as well
as of the cell interior. Employing NIH/3T3 cells infected with a
temperature-sensitive mutant (ts25) of Rauscher murine leukemia virus and
producing no virus at 39° although all necessary protein components are
present, we have demonstrated that areas of the cell surface, which are
heavily labeled using anti-gp70 serum, protrude slightly and overlie dense
areas of the cytoplasm which, in turn, are labeled using anti-p30
serum.
Infant Brain Stem: Structural Correlation between Scanning Electron
Microscopy and the Rapid Golgi Technique
Authors: Quattrochi James J.
Published: June 2020

Reticular ultrastructure was studied in the magnocellular and
parvo-cellular complexes of postmortem infant brain stem with the
application of scanning electron microscopy (SEM). A correlative technique
using an AMR 1000A scanning electron microscope at 20,000 to 40,000 x and
the rapid Golgi method identified neuronal morphology and reticular
processes in sixty-one infants ranging in age from 1 day to 8 months. In all
cases the postmortem time did not exceed six hours. Dendritic projections in
SEM was compared with dimension and structure of dendritic spines in light
microscopy sections taken from the immediately adjacent area and stained
with rapid Golgi impregnations (Fig. 1&2). A strong resemblance is noted
in these structures. Stellate neuronal aggregations were observed within a
dense fibrillary neuropil (Fig. 3). HCL-etching before osmication of SEM
tissue showed a striking disruption of neuronal-glial interrelationships. In
addition, neurites in close parallel apposition appeared to resemble a
topographical synaptic arrangement (Fig. 4).
Influence of Exogenous Albumin on Intraendothelial Vesicles of Lymphatic
Capillaries
Authors: Yang V. V. , O’Morchoe P. J. , O’Morchoe C. C. C.
Published: June 2020

Vesicular transport across lymphatic endothelium is one of the possible
pathways for the transfer of protein from interstitium to lymph. In previous
studies, horseradish peroxidase (HRP) was used as a tracer to study
trans-lymphatic transport in the rat renal cortex. The results indicated
that the formation of intracytoplasmic vesicles could be stimulated by the
presence of tracer in the interstitium and thereby provided evidence that
these vesicles play a role in the transport of protein into lymph. However,
it is possible that a foreign protein such as HRP might induce in lymphatic
endothelium changes that are not necessarily simulated by native protein
administration. The present study therefore, was designed to investigate the
effect of an increase in the rat albumin on the volume and numerical density
of lymphatic endothelial vesicles in the rat.
Ultrastrucure of Peruvian and Aleutian Mummified Tissues
Authors: Rivera E.R. , Coughlin E.A.
Published: June 2020

Electron microscopy has been employed in the study of Egyptian and
Aleutian human mumified tissues (1,2). The Egyptian mummification process
apparently fixed some tissues well enough to allow observation of some
cytoplasmic organelles (1). In observed Aleutian tissues, nucleoli and
possibly endoplasmic reticulum have been found in cartilage but not in other
tissues (2). The use of TEM methods may provide some indication of the
preservation procedure during mummification.

Arm muscle and pleura from Peruvian and Aleutian mummies were cut into 1
mm cubes and floated in 5% glutaraldehyde in 0.075 M PIPES buffer for 2
weeks at 4°C. This procedure allowed rehydration of tissue and fixation to
proceed simultaneously. These tissues were then post-fixed in 2%
OsQ4 and embedded in Spurr’s low viscosity resin
(3) and sectioned for TEM. Functional human striated muscle and pleura were
similarly prepared as controls.
Electron Diffraction from DNA Crystals
Authors: Downing Kenneth H.
Published: June 2020

Thin, broad crystals of DNA can be grown by slow precipitation in
ethanolic aqueous solution (1,2). Crystals of this form are well suited to
study by electron diffraction and electron microscopy. In preliminary
experiments to test the feasibility of applying electron crystal 1ographic
techniques to obtain a direct structure determination of the DNA in these
crystals, we have obtained electron diffraction patterns from the crystals.
These patterns are the first diffraction patterns of any kind to be obtained
from single crystals of highly polymerized DNA.
X-Ray Analysis of Sediment Regions and Transport of Sediment Particular
Material on the Gill of the Fingernail Clam, Musculium Transversum
Authors: Paparo Anthony , Murphy Judith A. , Sparks Richard
Published: June 2020

Fingernail clams are dominant bottom dwelling animals in some waters of
the midwestern part of the U.S. These clams prefer big river habitats with a
silt bottom where peak numbers may exceed 100,000/m2 as
in Keokuk Pool, Mississippi R. In the mid 1950’s, fingernail clams
disappeared from a 100-mile section of the Illinois R., a tributary of the
Mississippi R., due to unknown causes. In order to determine if the unknown
factor(s) in the Illinois R. are present in the bed of this river, a
sediment core of material was obtained. This material was divided into four
samples (A thru D, upper to lower region, respectively). Particle matter
from each sample was characterized as to size(μm), mass(mg/1), and
concentration(particles/1). The lateral cilia on the gill (Fig. 1) of the
fingernail clam are primarily responsible for the transport of sediment
particles over the lamellae. These cilia are under the control of the
nervous system and as such can respond directly to adverse environmental
stress factors. Therefore, gill preps were isolated and subsequent
measurement of the effects of temperature on rate(mm/sec) of sediment
transport of samples A thru D were determined from dorsal to ventral border
of the gill. For x-ray analysis, mud samples were dried and mounted on C
stubs, coated with C, and examined in a Cambridge IIA SEM fitted with an
Ortec computer-based EDS system.
The Interaction of Blood with Amorphous Carbon
Authors: Rudee M. L. , Price T. M.
Published: June 2020

When in contact with blood, some materials cause relatively little
alteration in the natural properties of the blood, while others rapidly
cause the formation of a clot. Thus understanding how blood reacts with
foreign materials has both scientific importance, in understanding the
details of clotting mechanisms, and practical consequences, in materials
selection for prosthetic applications.

It has been observed that the layer adsorbed on all synthetic materials
in contact with blood appears to be the same by all techniques thus far
utilized, no matter whether the material is bio-compatible or causes
clotting. In order to attack this paradox, we have initiated a study of the
morphology of the early stages of the interaction of blood with a foreign
material, amorphous carbon, that is both convenient for electron microscopy
and is an important prosthetic material.
Introductory Remarks
Authors: Mohri H.
Published: June 2020

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.
Rate of Sublimation of Ice by Radiative Heating in Freeze-Etching
Authors: Talmon Yeshayahu
Published: June 2020

To bring out details in the fractured surface of a frozen sample in the
freeze fracture/freeze-etch technique,the sample or part of it is warmed to
enhance water sublimation.One way to do this is to raise the temperature of
the entire sample to about -100°C to -90°C. In this case sublimation rates
can be calculated by using plots such as Fig.1 (Talmon and Thomas),or by
simplified formulae such as that given by Menold and Liittge. To achieve
higher rates of sublimation without heating the entire sample a radiative
heater can be used (Echlin et al.). In the present paper a simplified method
for the calculation of the rates of sublimation under a constant heat flux F
[W/m2] at the surface of the sample from a heater
placed directly above the sample is described.
Water Containing Epon 812/815 Embedding Method for Electron
Microscopy
Authors: Shinagawa Yoshiya , Shlnagawa Yasuko , Uchida Sadao
Published: June 2020

The special types of epoxy resins such as Durcupan or Quetol 651 have
been used as water-miscible embedding media for electron microscopy
hitherto. However, difficulties exist in handling of these resins,
especially in thin-sectioning. We have developed a method of polymerization
of the conventional epoxy resins, Epon 812, 815 (Shell Co.) and Luveak 812
(Nakarai Co.) in the presence of water. The authorsl) previously reported
melamine resins as water-containing embedding media which have been recently
sold by Nakarai Co. as Luveak A and B. The melamine resins as well as
aldehyde or urea resins have atypical electron staining. The
water-containing epoxy resins embedding method in this report provides usual
electron staining and facile sectioning like as the traditional Epon
embedding method. Negatively stained micrograph in part is obtained in this
method (Fig. la).
Approaches to the High Resolution Structure of Periodic Membrane
Proteins
Authors: Wiggins J.W.
Published: June 2020

Integral membrane proteins are particularly difficult to study at high
resolution for several reasons. Amino acid sequence determination may be
difficult because the fragmentation reagents cannot gain access to the
required site, fragments are insoluble in aqueous media, or lipids are
difficult to remove. X-ray diffraction studies cannot be undertaken without
large enough crystals. Electron microscopy studies of the usual sort cannot
be used because dehydration, negative staining, embedding, and other typical
procedures are incompatible with the preservation and contrasting of the
structure. Even determinations of molecular weight are made difficult by the
presence of bound lipid and polysaccharide.
High Resolution Imaging of Purple Membrane at Low Temperature
Authors: Hayward S. B.
Published: June 2020

When the purple membrane of Halobacterium halobium was successfully
imaged to 7Å resolution by Unwin and Henderson a natural question arose:
would it be possible to obtain higher resolution images, per¬haps even
approaching the resolution limit of the microscope? Such a possibility was
especially tempting since the specimen was known to be ordered to ~3Å
resolution. It is possible that such images would contribute new information
about the structure of bacteriorhodopsin. Furthermore, the methods used in
obtaining such images could serve as a model for future structural studies
of other ordered systems, some of which may contain important structural
information in the 7-4Å resolution range.
Reduction in Radiation Damage at Low Temperature
Authors: Egerton R. F.
Published: June 2020

Previous low-temperature measurements of radiation damage in organic
materials have been based on the diffraction pattern, changes in total
scattering power, background in the X-ray emission spectrum or the O - 10 eV
region of electron energy-loss spectra. Here we observe instead the 200-600
eV region of the energy-loss spectrum, which contains information relating
to the concentration of carbon, nitrogen and oxygen present in a thin
sample.

Specimens were irradiated by 80 keV electrons in a JEM IOOB transmission
microscope fitted with a specially-constructed specimen holder which could
be cooled to 77°K by circulation of liquid nitrogen. Cooled apertures above
and below the specimen reduce heat radiation and possible condensation of
residual gases from the surroundings. For the dose rates (<0.4 mA cm"2)
and specimen thicknesses (< 50 nm) employed here, temperature rise due to
the electron beam is expected to be negligible7.
Enlarged Crystalline Patches on the Plasma Membrane of Yeast
Protoplasts
Authors: Sosinsky G. , Schekman R. , Glaeser R.
Published: June 2020

The crystalline patches of intramembraneous particles that form in the
yeast plasma membrane, under stationary state physiological conditions,
represent a potentially interesting specimen for high resolution electron
microscopy. Isolation of these crystalline membrane patches first requires
removal of the cell wall and the formation of osmotically fragile yeast
protoplasts. In developing a procedure for the isolation of these
crystalline membrane patches, we have found that the intramembraneous
particles form much larger crystalline patches in protoplasts than in intact
yeast cells. We have performed deep etch experiments and have found that the
crystalline array of particles is not expressed on the extracellular surface
of the plasma membrane.