bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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
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.
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.
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.
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.
The Nature of the Intramembrane Particle
Authors: Verkleij A.J. 
Published: June 2020

Freeze-fracturing splits membranes into two helves, thus allowing an
examination of the membrane interior. The 5-10 rm particles visible on both
monolayers are widely assumed to be proteinaceous in nature.
Most membranes do not reveal impressions complementary to particles on
the opposite fracture face, if the membranes are fractured under conditions
without etching. Even if it is considered that shadowing, contamination or
fracturing itself might obscure complementary pits', there is no
satisfactory explanation why under similar physical circimstances matching
halves of other membranes can be visualized. A prominent example of
uncomplementarity is found in the erythrocyte manbrane. It is wall
established that band 3 protein and possibly glycophorin represents these
nonccmplanentary particles. On the other hand a number of membrane types
show pits opposite the particles. Scme well known examples are the ";gap
junction',"; tight junction, the luminal membrane of the bladder epithelial
cells and the outer membrane of Escherichia coli.
Observation of Wet Specimens Using a Modified Cambridge Mark II
SEM
Authors: Neal Richard J. , Mills Addison 
Published: June 2020

It has become possible in recent years to observe hydrated specimens in
the presence of water in the SEM. Since the advent of the wet cell in 1960
by Thornley1, followed by Lane's work to develop the
environmental cell in 19702, and culminating in the
extensive advances made by Robinson throughout the
1970's3, the development of a method to observe wet
specimens in a SEM while maintaining good image quality and high resolution
capabilities has become a reality. A Cambridge Mark II Stereo-scan SEM has
likewise been modified to study hydrated systems. The modifications made to
the Mark II to allow it to be used as an environmental scanning electron
microscope (ESEM) follow.
A new specimen stage was fabricated and substituted for the Mark II
specimen stage. This new stage has a reservoir for holding 2-3 ml of water,
and is capable of controlled cooling to below O°C Cooling is accomplished by
flowing cold ethanol through this specimen stage.
A separate mechanical rotary pump was used to evacuate the specimen
chamber and the pressure was monitored using a U-tube mercury
manometer.
Applications of Electron Energy Loss Spectroscopy in Materials
Science
Authors: Krivanek Ondrej L. 
Published: June 2020

The electron energy loss spectrometer developed at Berkeley differs from
most other ones in four ways: 1) it uses the projector lens crossover as the
spectrometer entrance object plane, 2) its magnet is asymmetric so that the
entrance object is de-magnified about 5x, 3) it counts electrons admitted
through the energy-selecting slit singly at rates up to 20MHz while adding
zero dark count, and 4) it fits neatly at the back of the available leg
space of the electron microscope, and requires no substantial alterations to
the microscope.
The energy resolution attainable routinely at any primary voltage is 3eV
over an energy loss range 0 to 1keV, as illustrated by resolving the π*
transition on the K-edge of amorphous carbon (Fig. 1). The 3 eV limit comes
mainly from 120Hz stray magnetic fields (the 60Hz component has been
compensated out). Fast scanning of the spectrum improves the resolution to
1eV (Fig. 2). This indicates that with proper magnetic shielding of the
electron flight path, especially in the microscope viewing chamber which is
made out of brass, the energy resolution attainable with the spectrometer
will be limited only by the energy spread of the primary beam.
Experimental investigation of beam-steering applied to 2 × 2 MIMO system with single receiving RF chain and time-modulated antenna array
Authors: Bogdan Grzegorz , Godziszewski Konrad , Yashchyshyn Yevhen 
Published: June 2020

AbstractMultiple antennas and multiple radio frequency (RF) chains in both the transmitter and receiver are required in conventional radio systems employing the multiple-input multiple-output (MIMO) method. This paper presents an experimental investigation of a beam-steering time-modulated MIMO receiver with a single RF chain. Implementation of the receiver is based on a time-modulated antenna array (TMAA) and a software-defined radio. The sidebands generated inherently by the TMAA are utilized as virtual spatial channels with the beam-steering functionality. Performance of the system is investigated experimentally. The bit error rate and condition number of the channel matrix are examined for different radiation patterns in order to determine favorable configurations in a given multipath environment. Obtained results show a considerable impact of the beam-steering on the performance of MIMO transmission.
An Examination of the Spanish Translation of the 50-item International Personality Item Pool Big-five Inventory in a Spanish Speaking Peruvian Sample
Authors: Hughes David J. , de Olazabal Daniel Pizarro , Kratsiotis Ioannis K. , Twumasi Ricardo , Booth Tom 
Published: June 2020

Abstract
The International Personality Item Pool (IPIP) five-factor model inventories are widely used for personality research and have been translated into multiple languages. However, the extent of the psychometric assessment of translated scales is variable, often minimal. The lack of psychometric scrutiny is particularly problematic because translation is an inherently complex process. Here, we present a structural analysis of one Spanish translation of the 50-item IPIP five-factor inventory in a sample of Peruvian, non-university educated, working adults (n = 778). A global confirmatory factor analytic (CFA) model of the a priori five factors failed to fit. So too did single factor models for four of the five factors, the exception being Neuroticism. Fit was improved via use of an exploratory structural equation measurement model, but the resultant solution showed very poor theoretical coherence. So, we explored the data for systematic measurement artefacts and sought to model them to improve the psychometric properties of the scale. Specifically, the pattern of factor loadings suggested that the lack of coherence might be due to the effects of the valence of item wording (i.e., positively or negatively worded items). CFA models including five substantive factors and a series of method factors modelling shared covariance based on item wording, improved fit and coherence. This investigation suggests that unless method factors are explicitly modelled the tested Spanish translation may not be suitable for use in certain Spanish-speaking countries or samples composed of non-university educated participants. More broadly, the study has implications for many translated scales, especially when used without thorough psychometric evaluation.
Identifying Perceptual, Motor, and Cognitive Components Contributing to Slowness of Information Processing in Multiple Sclerosis with and without Depressive Symptoms
Authors: Lubrini Genny , Periáñez José A. , Fernández-Fournier Mireya , Tallón Barranco Antonio , Díez-Tejedor Exuperio , Frank García Ana , Ríos-Lago Marcos 
Published: June 2020

Abstract
Increasing findings suggest that different components of the stimulus-response pathway (perceptual, motor or cognitive) may account for slowed performance in Multiple Sclerosis (MS). It has also been reported that depressive symptoms (DS) exacerbate slowness in MS. However, no prior studies have explored the independent and joint impact of MS and DS on each of these components in a comprehensive manner. The objective of this work was to identify perceptual, motor, and cognitive components contributing to slowness in MS patients with and without DS. The study includes 33 Relapsing-Remitting MS patients with DS, 33 without DS, and 26 healthy controls. Five information processing components were isolated by means of ANCOVA analyses applied to five Reaction Time tasks. Perceptual, motor, and visual search components were slowed down in MS, as revealed by ANCOVA comparisons between patients without DS, and controls. Moreover, the compounding effect of MS and DS exacerbated deficits in the motor component, and slowed down the decisional component, as revealed by ANCOVA comparisons between patients with and without DS. DS seem to exacerbate slowness caused by MS in specific processing components. Identifying the effects of having MS and of having both MS and DS may have relevant implications when targeting cognitive and mood interventions.
VIPIR and 50 MHz Radar Studies of Gravity Wave Signatures in 150‐km Echoes Observed at Jicamarca
Authors: Reyes Pablo M. , Kudeki Erhan , Lehmacher Gerald A. , Chau Jorge L. , Milla Marco A. 
Published: June 2020

AbstractRange‐time‐intensity (RTI) plots of 50 MHz radar backscatter detected at Jicamarca from the 150‐km region of the equatorial ionosphere exhibit necklace‐shaped multilayered structures first reported by Kudeki and Fawcett (1993, https://doi.org/10.1029/93GL01256). The backscatter layers also exhibit quasi‐periodic intensity fluctuations with periods of about 5–15 min and are separated from adjacent layers by thin and undulating regions of no detectible power returns. A study of the fluctuating backscatter layers and undulating gap regions will be presented using VIPIR ionosonde data taken at the Jicamarca Radio Observatory simultaneously with high‐resolution 50‐MHz radar backscatter data. VIPIR virtual reflection height variations in time are noted to match the RTI gap‐region undulations very closely at selected VIPIR frequencies (or, equivalently, electron densities at reflection heights). This matching enables assigning “true heights” to VIPIR virtual height contour maps, and a joint study of the contour maps with the 50‐MHz radar RTI maps strongly suggests that correlated fluctuations and undulations observed in VIPIR and 50‐MHz radar data are indicative of gravity wave‐induced variations in the 150‐km region ionosphere. Accordingly, a complete explanation of the 150‐km echo phenomenon will need to include gravity wave coupling and forcing effects in the enhancement and suppression processes that can account for the observed fluctuations and gap‐region features of necklace‐shaped 150‐km echo maps.