bluuebunny/crossref_metadata_2025 huggingface dataset:
A Proposed Mechanism for the Formation of Immune Complexes in Mercury
Associated Glomerulonephritis
Authors: Tubbs R. R. , McMahon J. T. , Gephardt G. N. , Barenberg S.
Published: June 2020

Nephrotoxicity has been associated with several heavy metals including
mercury, gold, bismuth, cadmium, and lead. Mercuric nephropathy may be
manifested as a selective necrosis of proximal tubules in experimental
animals given large intravenous doses of mercury or as an immune complex
glomerulonephritis when small doses are administered subcutaneously over a
long period of time. Two patients with industrial exposure to mercury were
admitted to The Cleveland Clinic following the occurrence of proteinuria. A
multidisciplinary approach was undertaken in order to more precisely define
the pathogenic mechanisms involved in the production of the glomerular
lesion.
Pseudotendon: Ultrastructural Similarities to Scar Development
Authors: Kischer C.W. , Arem A.J.
Published: June 2020

Pseudotendon is a remarkable attempt to reform a working, gliding, unit
of organized collagen in the wake of tendon transection. Tension forces
transmitted from the severed muscle-tendon unit through the newly forming
scar may organize the collagen into a functional configuration. The dynamics
of collagen remodeling appear precise and orderly, and excess collagen is
not built up as it is in the case of hypertrophic
scar1.

Since tendon repair and regeneration of skin each involve formation of
scar tissue, but, since the former process is abbreviated and the latter is
prolonged a comparison of the two cases with respect to scar production
seems beneficial. The ultrastructural character of each may show significant
differences which could account for the different fates of each healing
process.
Bluetongue Virus Maturation in Cultured Cells
Authors: Foster Neil M. , Breckon Ruth D.
Published: June 2020

It was reported that cell release of bluetongue virus (BTV) occurred via
breaks in the plasma membrane,1
extrusion,2 budding,3 and by
cell lysis.4 Most authors have stated that BTV
essentially has no envelope, although the presence of a membrane on at least
a small proportion of the virions has been reported.3,5
One study found that 99% of BT virions had density of ≃1.2 in sucrose and
were each enclosed within a membrane.6 These authors
concluded that the common BTV particle was membraned and not “naked” as
conventionally described. Therefore, in order to gain more insight into the
structure of BTV, we reexamined maturation and release of BTV from infected
cells.
High Voltage Electron Microscopy of Viral Inclusion Bodies
Authors: Mazzone H.M. , Engler W.F. , Wray G. , Szirmae A. , Conroy J. , Zerillo R. , Bahr G.F.
Published: June 2020

Viral inclusion bodies isolated from infected pest insects are being
evaluated by the U.S. Dept. of Agriculture as biological insecticides
against their hosts. Our research on these inclusion bodies constitutes part
of an effort to support their approval by the Environmental Protection
Agency as insect control agents.

The inclusion bodies in this study are polyhedral in shape and contain
rod-shaped viral particles. When ingested by pest insects, the inclusion
bodies are broken down in the insect gut and release the viral particles
which infect and multiply in the nuclei of host cells. These viruses are
termed nucleopolyhedrosis viruses (NPV) and are representatives of the
baculoviruses (Wildy, P. 1971 IN J.L. Melnick, ed., Monographs in Virology,
vol. 5, S.Karger, New York).
Fine Structure of the Lateral Area of the Posterior Rhombencephalic Tela
of the Bullfrog, Rana Catesbiana
Authors: Michaels J. E. , Tornheim P. A.
Published: June 2020

In mammals, the caudal roof of the fourth ventricle consists of an inner
layer of ependymal cells and an outer layer of leptomeningeal cells. It
contains specializations in the form of tufts of choroid plexus for the
elaboration of cerebrospinal fluid (CSF) as well as gross apertures that
permit open communication between the ventricular system and the
subarachnoid space, an essential feature for mammalian CSF circulation. In
the bullfrog, as in most submammals, the roof of the fourth ventricle
contains a rostral rhombencephalic choroid plexus with no gross evidence of
fourth ventricular apertures. Communication between the ventricular system
and the subarachnoid space in this animal, however, has been demonstrated to
occur by way of microscopic openings or pores in the caudal roof of the
hindbrain or the posterior rhombencephalic tela choroidea.
The Valves of Canine Renal Hilar Lymphatics
Authors: Albertine K.H. , Fox L.M. , O’Morchoe C.C.C.
Published: June 2020

Lymph moves through the lymphatic microcirculation with the aid of
valves which are oriented for centrally directed flow. The morphological
arrangement of these valves is controversial and two theories have been put
forward. The proponents of one theory (1,2,3) maintain that lymphatic valves
are primarily bicuspid, that is they occur as two semilunar cusps attached
at their base to opposite sides of the vessel wall for a variable length,
although valves with 3-5 cusps have been described. The alternative
hypothesis is that lymphatic valves are primarily funnel-shaped (monocuspid)
with the base circumferentially attached to the vessel wall (4).
Morphological techniques which have been used to develop the two opposing
theories include light microscopy (LM), TEM, and stereomicroscopy. We have
used SEM, which provides three-dimensional images of entire valves, in
combination with LM and TEM to investigate the architecture of canine renal
hilar lymphatic valves.
The Occurrence of Polycomplexes During the Sporogenesis in Psilotum
Nudum
Authors: Lee Kit W.
Published: June 2020

The structure of the polycomplexes has been extensively studied in
recent years (1,2,3). Theres structures are usually described as stacks or
aggregates of the tripartite synaptonemal complexes. Although the presence
of the synaptonemal complexes is a consistent feature in the late zygotene
or pachytene stages of chlasmate meiosis and Its role in the processes of
chromosome synapsis and crossing over has been suggested (4), the function
of the polycomplexes remains obscure. Most of our understandings of the
polycomplexes are obtained from the observations during the gametogenesis of
the insects, and only a few examples of this structure in fungi and higher
plants have been reported. The present study examines the occurrence of
polycomplexes during the sporogenesis in the primitive vascular
plant.

Sporangia at different developmental stages were fixed with 3%
glutaraldehyde in 0.1 M phosphate buffer, and postflxed in 2% osmium
tetroxide. Dehydration was carried out with the ethanol series followed by
embedding in Epon 812. Ultrathln sections were stained with uranyl acetate
and lead citrate.
The Reconstruction of Large Microscopic Bodies from Wide-Field Electron
Micrographs
Authors: Yang Grace C.H. , Morrison Ashton B.
Published: June 2020

The technique of wide-field electron microscopy can be applied to
reconstruct 3-D models of microscopic bodies which are too large for the
conventional electron microscopy, yet whose details are too minute to be
resolved by light microscopy. The renal glomerulus is a good example. The
branching patterns of its smaller capillaries are so tortuous and complex
that the vascular arrangement of the glomerular capillary tuft has been the
subject of much controversy.

We have completed a project in which the 3-D models of three rat
glomeruli have been constructed. The models are made of low density
styrofoam discs. They are large (about I6”xl6”x22”) yet light in weight
(about 1.8 gm), and can be dissected to reveal internal intricate
structures. They disclose much interesting information not previously
reported. For instance, all three glomerular models are consisted of three
major lobules, e.g. frontal right, frontal left, and dorsal central. The
lobule occupying the central portion bridges the two lateral lobules with
few anastomoses, but no direct connection exists between the two lateral
lobules. There are two efferent openings which extend to the outside of
Bowman’s capsule, the right opening is the end of right lobules, and the
left opening is the end of left lobule.
The Mechanomorphology of Microtubule Sliding
Authors: Satir P. , Wais-Steder J. , Avolio J.
Published: June 2020

In 1977, Sale and Satir showed that active microtubule sliding in
trypsin-treated Tetrahymena axonemes is always of a single polarity. If the
doublet bearing active arms is labelled N, by convention, the doublet that
is pushed by those arms is N+l. In active sliding in trypsin-treated
axonemes doublet N+l is always displaced tipwards with respect to
N.

Several different configurations of the dynein arms have been described.
These include: (1) an extended configuration, where the dynein arms are
tilted about 40° towards the base of the axoneme and are long enough to span
the space between doublets N and Ntl completely (2) a standard, unattached
image, such as is usually seen in thin section. In this configuration, the
arms do not span the interdoublet gap. (3) the rigor image, where the arms
always bridge the gap. This differs from the extended configuration because
tilt is often absent, so that the arms often lie normal to doublets N and
N+l.
Identification of Intramembrane Particles by Pre- and Post-Fracture
Labelling Techniques: A Progress Report
Authors: Rash J. E. , Johnson T. J. A. , Hudson C. S. , Copio D. S. , Graham W. F. , Eldefrawi M. E. , Giddings F. D.
Published: June 2020

Conventional freeze-fracture replicas provide for high resolution,
three-dimensional replication of the internal macromolecular architecture of
cell membranes, but they have the distinct disadvantage that no biologically
rele¬vant macromolecules remain for subsequent in situ labelling and
positive identification. Recently, several ingenious freeze-fracture
techniques have been devised to localize biochemical components before the
tissues are diges-ted away. These methods include (a) freeze-fracture
autoradiography of the frozen whole mount preparation (1, 2) and (b) deep
etching (freeze-drying) to expose immunoglobins or other large protein
markers attached to membrane surfaces (3). However, freeze-fracture
autoradiography has insufficient resolution to permit localization of labels
to individual intramembrane particles (IMPs) exposed by the cleaving
process, while deep etching to reveal membrane surfaces does not reveal
IMPs. To overcome some of these difficulties, we recently introduced the
"sectioned replica technique" to provide a method for direct and unambiguous
correlation of freeze-fracture and thin section images within a single
electron micrograph (4). The fractured and replicated tissues are thawed,
but instead of digesting the tissues, the replica-tissue sandwich is
post-fixed in 30% buffered glycerol solution con-taining 1%
OsO4, post-stained, embedded in plastic, and
sectioned parallel to the replica-tissue interface. Using this
sectioned-replica technique, we have been able to obtain (a) pre-fracture
radioisotope-labelled mouse neuromuscular junctions and (b) pre- and
post-fracture immunoferritin and colloidal gold-labelled membrane fragments
and intact neuromuscular junctions.
Localization of Intracisternal a Particle Antigens in Neoplastic Cells
and Preimplantation Mouse Embryos
Authors: Huang Thomas T.F. , Calarco Patricia G.
Published: June 2020

The stage specific appearance of a retravirus, termed the Intracisternal
A particle (IAP) is a normal feature of early preimplantation development.
To date, all feral and laboratory strains of Mus musculus and even Asian
species such as Mus cervicolor and Mus pahari express the particles during
the 2-8 cell stages. IAP form by budding into the endoplasmic reticulum and
appear singly or as groups of donut-shaped particles within the cisternae
(fig. 1). IAP are also produced in large numbers in several neoplastic cells
such as certain plasmacytomas and rhabdomyosarcomas. The role of IAP, either
in normal development or in neoplastic behavior, is unknown.
Scanning Electron Microscopy of the Developing Optic Cup and Fissure in
the Rat
Authors: Morse D. E.
Published: June 2020

Formation of an adult organ from its developmental anlage most often is
the consequence of considerable alteration in structure during the embryonic
and/or fetal periods. Some of the most widely recognized alterations involve
cell differentiation, extracellular matrix changes (including cell coat),
cell death, and fusion of proliferating tissues. The mechanisms responsible
for fusion processes have been the foci of numerous investigations since
failure of fusion may result in disfigurement, loss of function and, in some
cases, death.
Mammosomatotroph Cell Adenoma of the Human Pituitary
Authors: Horvath E. , Kovacs K. , Killinger D.W. , Smythe H.S. , Platts M.E. , Weiss M.S. , Ezrin C.
Published: June 2020

In the morphologic study of surgically-removed pituitary adenomas,
histology, electron microscopy as well as immunocytochemistry at the light
microscopic and ultrastructural level were used. In material of 370
adenomas, 226 tumors (61.7%) were found to derive from the “acidophil” cell
line. Thirty-one of these were densely granulated growth hormone cell
adenomas; 38 were sparsely granulated growth hormone cell adenomas; 1 was
composed of densely granulated prolactin cells and 114 of sparsely
granulated prolactin cells. The latter represent the most common tumor type
in the human pituitary. Twentyone adenomas were mixed, consisting of growth
hormone cells and prolactin cells; 17 tumors were classified as acidophil
stem cell adenomas. The latter are immature, aggressive neoplasms assumed to
originate in the common precursor of growth hormone cells and prolactin
cells.
Ultrastructural Study of Apocrine Differentiation in Human Mammary
Carcinoma: Correlation of Granule Content With Sex Steroid Binding
Authors: Levine S. E. , Brinkhous A. D. , McCarty K. S. , Mossier J. A. , McCarty K.S.
Published: June 2020

A variant of ductal carcinoma of the human breast which has been
designated apocrine carcinoma has distinctive light and electron microscopic
features. Such tumors comprise approximately 0.5% of breast carcinomas.
Abundant cytoplasmic membrane bound vesicles (400-600 nm) with dense
homogeneous osmophilic cores characterize these tumors. These granules are
also seen in apocrine metaplastic breast epithelial
lesions1 and appear to be responsible for the
finely granular eosinophilic cytoplasm observed by light microscopy. A high
content of intermediate affinity non-saturable 4S progesteroneestrogen
binding protein (PEBP) in apocrine carcinoma has been
reported.2 The present ultrastructural study
evaluates the presence of apocrine granules in infiltrating ductal carcinoma
(NOS) to determine if a correlation exists between apocrine granule content
and the quantity of PEBP present.
Positional Microstructure of The Human Lung: Microdissection and
Correlative Microscopy Techniques (LM, SEM, TEM)
Authors: Bastacky J. , Sprague L.M. , Hayes T. L
Published: June 2020

The scanning electron microscope (SEM) can image surface features in
biological samples over a broad range of magnification from the tissue level
to the subcellular level. The power of SEM analysis can be fundamentally
increased by presenting to the microscope a surface prepared such that
structure of the sample is revealed at each level of magnification.
Studies on Lipidic Intramembrane Particles (LIPS)
Authors: Stewart T. P. , Hui S. W.
Published: June 2020

Particulated features seen on freeze fractured faces of membranes are
commonly believed to be of proteinaceous origin. Recently, particulated
features have been observed on the freeze fractured faces of liposomes
without the addition of protein1. The origin of this
particulated feature, termed lipidic intramembrane particles (LIP), is not
clear. It has been suggested that some of the LIPs could be inverted
micelles of lipids1.
Intramembrane Particles (IMPs) in Halobacterium Halobium
Authors: Robertson J.D. , Schreil W. , Reedy M.
Published: June 2020

Whole organisms of Halobacterium halobium were frozen in liquid propane
and fractured in a Balzers 360 apparatus at ~−140ÅC at
~10−7 Torr and replicated without etching. Fig. 1
is a reverse print of a micrograph of two fractured organisms. The one above
shows two purple patches in the EF face and the one below one in the PF
face. The area labelled “1” was used for the filtered image in Fig. 2 and
area “2” for the one in Fig. 3. The arrows in Figs. 2-3 indicate the centers
of adjacent repeating units of the hexagonal lattice (d ~60Å). The repeating
unit in Fig. 2 is a glob of metal representing three bacteriorhodopsin (BR)
molecules. Each repeating unit in Fig. 3 consists of a ring of metal
surrounding a dark shadow in the center of which there is a bright spot of
metal. Each dark shadow ring is the complement of each ~50Å circular glob of
metal in Fig. 2. Hence it is the impression of a set of three BR molecules
around a three-fold axis of the molecular lattice. Note that there is a
slight depression perpendicular to the shadowing direction at the edge of
the purple membrane patch (black arrow). The area labelled “3” is another
purple membrane patch turned up ~45°. The regular pattern is prominent here
because of the shadowing angle. Note the many large intramembrane particles
that at first sight appear globular. Many of these cast rectangular shadows
(inset enlargements above of particles labelled “4-10)”. Some particles, eg.
#7, are linear. The angularity of the shadows shows that these particles
represent water crystals (Gross, H., O. Kuebler, P. Bass and H. Moor, 1978,
J. Cell Biol. , 79:646). Fig. 4 is an enlargement of a PF face showing
triplets of metallic aggregates ~50Å in diameter spaced ~100Å apart. Several
are encircled and the spacing indicated by arrows. Fig. 5 is an EF face in
which complementary triplets can be seen as sets of three dark circular
shadows (encircled to the lower left). Note the very small (<10Å) spots
of metal approximately in the center of some triplet components. The
center-to-center spacing of ~100Å of three adjacent triplets is indicated to
the upper center. The triplet structures in the EF and PF faces are
complementary. The features of the filtered image of the EF face in Fig. 3
indicate that the spots of metal in the center of the triplet impressions in
Fig. 4 are significant. Fig. 6 is a diagram showing the BR lattice above
with three-fold axes separated by 62Å. In the lower part of the diagram the
appearance of the PF faces is shown at the same scale. Comparison shows that
each triplet consists of three sets of three BR molecules. Each ~50Å metal
glob in the triplet is therefore a replica of three bacteriorhodopsin
molecules. We interpret the <10Å spots in the dark ring shadows in Fig. 5
and the globs of metal around the ring shadows in the EF face as lipid
molecules. They are revealed by decoration and shadowing.
The U.S. Atom-Resolving Microscope Project
Authors: Gronsky R.
Published: June 2020

The largest project in transmission electron microscopy ever to be
undertaken in this country has recently been initiated within the Materials
and Molecular Research Division of the Lawrence Berkeley Laboratory due to
the support of the Division of Materials Research, Office of Basic Energy
Sciences, U.S. Department of Energy. This project has been given the name
“Atomic Resolution Microscopy” and its goal is to provide the
instrumentation and expertise necessary to conduct materials research
directly at the atomic level. Taking advantage of the best available
technology in electron-optical design, its core instrumentation is a unique
machine, the Atomic Resolution Microscope (ARM), which is to be built by
commercial manufacturers to the specifications of LBL and used in basic
research programs requiring atomic imaging capabilities. The project will
also include an in-house instrument development effort to maintain
state-of-the-art performance from the ARM. Details of history, organization
and performance specifications are outlined below.
HVEM Radiation Damage Studies: Past, Present and Future
Authors: Mitchell T.E. , Hobbs L.W.
Published: June 2020

First let it be said that this article is not intended to be a
comprehensive review of HVEM radiation damage studies. The reader will do
much better to peruse the writings of Urban, Kiritani, Cosslett and others,
or to scan the various HVEM symposium reports. Nor is this article intended
to justify the use of HVEM to develop suitable materials for fast-breeder
reactors, fusion reactors, ion implantation devices, nuclear waste disposal
or any other technological problem where radiation damage is important.
Rather, this article seeks to assess the role that HVEM has, can, and will
display in understanding the fundamental aspects of radiation damage
processes. The point to be made is that HVEM provides an excellent
scientific method of investigating the primary displacement process, and,
especially, secondary defect formation. However, although the electron
damage process is much simpler than neutron or ion damage, HVEM damage
observations still must be evaluated with extreme caution.
Microanalysis of Light Elements with an Ultrathin Window X-Ray
Spectrometer
Authors: Thomas L. E.
Published: June 2020

Compared to electron energy loss spectrometry (ELS), energy-dispersive
X-ray (EDX) spectrometry at first appears inefficient for microanalysis of
light elements. K-shell ionization cross sections increase rapidly at low
atomic numbers, as shown in Figure 1, while the corresponding X-ray yields
remain about constant. Also, the efficiency of the EDX detector decreases at
low X-ray energies (Figure 2) due to X-ray absorption in its inactive outer
layers and protective window. Even if the window is eliminated, these
considerations clearly favor ELS for detection of small, light element
masses.
Microanalysis of Precipitate Free Zones (PFZ) In Al-Zn-Mg and Cu-Ni-Nb
Alloys
Authors: Raghavan M.
Published: June 2020

Due to their possible detrimental effect on the stress corrosion and
mechanical properties, Precipitate Free Zones (PFZ) in precipitation
hardening alloy systems have been the subject of several investigations.
Earlier studies by Nicholson and other workers convincingly demonstrated
that PFZ can form as a result of vacancy concentration profile near the
grain boundaries (1,2). Based on these and other investigations, PFZ in
alloys are generally attributed as due to either solute depletion or vacancy
depletion. Recently, several investigations have applied microanalytical
techniques (plasmon loss, electron energy loss and X-ray microanalysis) to
understand the solute profile in the PFZ particularly in the Al-Mg and
Al-Zn-Mg systems (3,4). The present investigation was conducted to provide a
better understanding of the formation of PFZ in alloys by analyzing the
solute profiles in the PFZ by X-ray analysis in two alloys (5). One was an
Al-2.2% Zn-4.7% Mg* alloy which has been demonstrated to form PFZ due to the
vacancy concentration profile (1,2). The other alloy is a Cu-30% Ni-0.9% Nb
alloy in which the PFZ was suggested to form due to depletion of Nb (6).
Samples of these alloy samples were examined after selected heat
treatments.
Vernalization affects absorption and translocation of clopyralid and aminopyralid in rush skeletonweed (Chondrilla juncea)
Authors: Burke Tara L. , Burke Ian C.
Published: June 2020

The developmental status of perennial weeds such as rush skeletonweed (Chondrilla juncea L.) can influence herbicide absorption and translocation. Differential efficacy between fall and spring applications suggests vernalization impacts herbicide absorption and translocation in other perennial asters. Clopyralid and aminopyralid absorption and translocation were quantified in nonvernalized and vernalized plants following application of 14C-labeled herbicides 2, 4, 8, 24, and 72 h after treatment. Less 14C clopyralid was absorbed, and at a slower rate, in vernalized plants. Movement out of the treated leaf was slower, with 14C clopyralid translocating more rapidly than 14C aminopyralid. More 14C moved to the roots in nonvernalized plants compared with vernalized plants, regardless of herbicide. Increased translocation to belowground survival structures is needed for effective control of C. juncea.
Global View of Ionospheric Disturbance Impacts on Kinematic GPS Positioning Solutions During the 2015 St. Patrick's Day Storm
Authors: Yang Zhe , Morton Y. T. Jade , Zakharenkova Irina , Cherniak Iurii , Song Shuli , Li Wei
Published: June 2020

The 2015 St. Patrick's Day geomagnetic storm caused numerous disturbances of the ionosphere, particularly, plasma irregularities, large‐scale traveling ionospheric disturbances, and equatorial ionization anomaly enhancement. This study for the first time quantifies the global‐scale impacts of the ionospheric disturbances on Global Positioning System (GPS) precise point positioning (PPP) solutions during this extreme space weather event by taking advantage of 5,500 + GNSS stations installed worldwide. The overall impact was more severe at high latitudes, while PPP degradation at low latitudes was associated with different types of ionospheric disturbances. Specifically, our results show that kinematic PPP solutions degraded following an intensified auroral particle precipitation during the storm's main phase (06–23 UT) when up to ~70% of the high‐latitude stations experienced degraded position solutions in the multimeter range at 16–18 UT. Around magnetic noon and midnight, the storm‐induced plasma irregularities caused notable PPP errors (>10 m) at high latitudes. Interhemispheric differences were observed with a more severe impact seen in the Southern Hemisphere, where PPP outage lasted for ~12 hr during the second main phase (12–23 UT). At low latitudes, post sunset equatorial plasma irregularities were suppressed across most longitudes, but large PPP errors (>2 m) associated with storm‐induced plasma bubbles were registered at the Indian sector at 14–18 UT. The storm‐induced equatorial ionization anomaly enhancement and large‐scale traveling ionospheric disturbances were responsible for the low‐latitude PPP degradation at dayside sectors. This study fills the research gap between physical and practical aspects of severe ionospheric storm effects.
Spatiotemporal Variations of Mesoscale Eddies in the Southeast Indian Ocean
Authors: Zhang Ningning , Liu Guoqiang , Liu Qinyan , Zheng Shaojun , Perrie William
Published: June 2020

Strong eddy activities exist in the Leeuwin Current (LC) and the South Indian Countercurrent (SICC) systems. Through a detailed investigation based on satellite observations, we find a cyclonic preference for eddies with more frequent genesis, longer lifespan, smaller size and stronger intensity in both systems. The evolutions of amplitudes, radii and total vorticities of eddies can be classified as the generation, stable, and decay stages; however, those of the EKE and relative vorticities lack the stable stage, due to planetary vorticity changes related to the meridional deflections, as eddies drift westward. Eddy properties exhibit significant seasonal and interannual variations. In the LC system, more and stronger eddies tend to be generated in winter and in La Niña years; while in the SICC system, eddy properties generally reach their peaks in spring and in years when the negative Southern Annular Mode (SAM) occurs. And eddy intensities in the SICC system are also modulated by ENSO with about a one‐year phase lag. Through instability analysis, we find that baroclinic instability is the most dominant contributor to the development of eddies. By contrast, barotropic instability mainly acts to dampen eddies. Advection of EKE makes almost no net contribution when spatially averaged, although it is locally significant. Pressure work and dissipation may be nonnegligible EKE sinks in the LC system. The EKE variations in these two systems have close connections through the westward‐propagating baroclinic instability anomalies, which may explain the phase lags between these two systems.
Hydrothermal Precipitation of Sanidine (Adularia) Having Full Al,Si Structural Disorder and Specular Hematite at Maunakea Volcano (Hawai'i) and at Gale Crater (Mars)
Authors: Morris R. V. , Rampe E. B. , Vaniman D. T. , Christoffersen R. , Yen A. S. , Morrison S. M. , Ming D. W. , Achilles C. N. , Fraeman A. A. , Le L. , Tu V. M. , Ott J. P. , Treiman A. H. , Hogancamp J. V. , Graff T. G. , Adams M. , Hamilton J. C. , Mertzman S. A. , Bristow T. F. , Blake D. F. , Castle N. , Chipera S. J. , Craig P. I. , Des Marais D. J. , Downs G. , Downs R. T. , Hazen R. M. , Morookian J.‐M. , Thorpe M.
Published: June 2020

Hydrothermal high sanidine and specular hematite are found within ferric‐rich and gray‐colored cemented basaltic breccia occurring within horizontal, weathering‐resistant strata exposed in an erosional gully of the Pu'u Poliahu cinder cone in the summit region of Maunakea volcano (Hawai'i). The cone was extensively altered by hydrothermal, acid‐sulfate fluids at temperatures up to ~400 °C, and, within strata, plagioclase was removed by dissolution from progenitor Hawaiitic basalt, and sanidine and hematite were precipitated. Fe2O3T concentration and Fe3+/∑Fe redox state are ~12 wt.% and ~0.4 for progenitor basalt and 46–60 wt.% and ~1.0 for cemented breccias, respectively, implying open‐system alteration and oxic precipitation. Hydrothermal high sanidine (adularia) is characterized by full Al,Si structural disorder and monoclinic unit‐cell (Rietveld refinement): a = 8.563(19) Å, b = 13.040(6) Å, c = 7.169(4) Å, β = 116.02(10)°, and V = 719.4(19) Å3. Hematite (structure confirmed by Rietveld refinement) is the predominant Fe‐bearing phase detected. Coarse size fractions of powdered hematite‐rich breccia (500–1000 μm) are dark and spectrally neutral at visible wavelengths, confirming specular hematite, and SEM images show platy to polyhedral hematite morphologies with longest dimensions >10 μm. Smectite and 10‐Å phyllosilicate, both chemically dominated by Mg as octahedral cation, are additional diagenetic hydrothermal alteration products. By analogy and as a working hypothesis, high sanidine (Kimberly formation) and specular hematite (Mt. Sharp group at Hartmann's Valley and Vera Rubin ridge) at Gale crater are interpreted as diagenetic alteration products of Martian basaltic material by hydrothermal processes.
Record Lack of Cyclones in Southern Australia During 2019
Authors: Pepler Acacia
Published: June 2020

Australia experienced its driest calendar year on record in 2019. A number of factors contributed to the persistently dry conditions, including a record‐low number of cyclones in the Australian region south of 30°S as well as very high numbers of anticyclones during the southern wet season (April–September). The record year is likely a result of natural climate variability together with an underlying trend. The number of cyclones in southern Australia has decreased since 1979, and the number of cool season anticyclones has increased, although large interannual variability means that these trends currently cannot be distinguished from natural variability. However, the longer NCEP1 and JRA55 reanalyses provide evidence of a long‐term decline in cyclone frequency in southern Australia since the 1950s.
High-resolution mapping of mitotic DNA synthesis regions and common fragile sites in the human genome through direct sequencing
Authors: Macheret Morgane , Bhowmick Rahul , Sobkowiak Katarzyna , Padayachy Laura , Mailler Jonathan , Hickson Ian D. , Halazonetis Thanos D.
Published: June 2020

DNA replication stress, a feature of human cancers, often leads to instability at specific genomic loci, such as the common fragile sites (CFSs). Cells experiencing DNA replication stress may also exhibit mitotic DNA synthesis (MiDAS). To understand the physiological function of MiDAS and its relationship to CFSs, we mapped, at high resolution, the genomic sites of MiDAS in cells treated with the DNA polymerase inhibitor aphidicolin. Sites of MiDAS were evident as well-defined peaks that were largely conserved between cell lines and encompassed all known CFSs. The MiDAS peaks mapped within large, transcribed, origin-poor genomic regions. In cells that had been treated with aphidicolin, these regions remained unreplicated even in late S phase; MiDAS then served to complete their replication after the cells entered mitosis. Interestingly, leading and lagging strand synthesis were uncoupled in MiDAS, consistent with MiDAS being a form of break-induced replication, a repair mechanism for collapsed DNA replication forks. Our results provide a better understanding of the mechanisms leading to genomic instability at CFSs and in cancer cells.
miR2118-dependent U-rich phasiRNA production in rice anther wall development
Authors: Araki Saori , Le Ngoc Tu , Koizumi Koji , Villar-Briones Alejandro , Nonomura Ken-Ichi , Endo Masaki , Inoue Haruhiko , Saze Hidetoshi , Komiya Reina
Published: June 2020

Reproduction-specific small RNAs are vital regulators of germline development in animals and plants. MicroRNA2118 (miR2118) is conserved in plants and induces the production of phased small interfering RNAs (phasiRNAs). To reveal the biological functions of miR2118, we describe here rice mutants with large deletions of the miR2118 cluster. Our results demonstrate that the loss of miR2118 causes severe male and female sterility in rice, associated with marked morphological and developmental abnormalities in somatic anther wall cells. Small RNA profiling reveals that miR2118-dependent 21-nucleotide (nt) phasiRNAs in the anther wall are U-rich, distinct from the phasiRNAs in germ cells. Furthermore, the miR2118-dependent biogenesis of 21-nt phasiRNAs may involve the Argonaute proteins OsAGO1b/OsAGO1d, which are abundant in anther wall cell layers. Our study highlights the site-specific differences of phasiRNAs between somatic anther wall and germ cells, and demonstrates the significance of miR2118/U-phasiRNA functions in anther wall development and rice reproduction.
Heterostructures formed through abraded van der Waals materials
Authors: Nutting Darren , Felix Jorlandio F. , Tillotson Evan , Shin Dong-Wook , De Sanctis Adolfo , Chang Hong , Cole Nick , Russo Saverio , Woodgate Adam , Leontis Ioannis , Fernández Henry A. , Craciun Monica F. , Haigh Sarah J. , Withers Freddie
Published: June 2020

To fully exploit van der Waals materials and their vertically stacked heterostructures, new mass-scalable production routes which are low cost but preserve the high electronic and optical quality of the single crystals are required. Here, we demonstrate an approach to realise a variety of functional heterostructures based on van der Waals nanocrystal films produced through the mechanical abrasion of bulk powders. We find significant performance enhancements in abraded heterostructures compared to those fabricated through inkjet printing of nanocrystal dispersions. To highlight the simplicity, applicability and scalability of the device fabrication, we demonstrate a multitude of different functional heterostructures such as resistors, capacitors and photovoltaics. We also demonstrate the creation of energy harvesting devices, such as large area catalytically active coatings for the hydrogen evolution reaction and enhanced triboelectric nanogenerator performance in multilayer films. The ease of device production makes this a promising technological route for up-scalable films and heterostructures.
Surface regulation enables high stability of single-crystal lithium-ion cathodes at high voltage
Authors: Zhang Fang , Lou Shuaifeng , Li Shuang , Yu Zhenjiang , Liu Qingsong , Dai Alvin , Cao Chuntian , Toney Michael F. , Ge Mingyuan , Xiao Xianghui , Lee Wah-Keat , Yao Yudong , Deng Junjing , Liu Tongchao , Tang Yiping , Yin Geping , Lu Jun , Su Dong , Wang Jiajun
Published: June 2020

Single-crystal cathode materials for lithium-ion batteries have attracted increasing interest in providing greater capacity retention than their polycrystalline counterparts. However, after being cycled at high voltages, these single-crystal materials exhibit severe structural instability and capacity fade. Understanding how the surface structural changes determine the performance degradation over cycling is crucial, but remains elusive. Here, we investigate the correlation of the surface structure, internal strain, and capacity deterioration by using operando X-ray spectroscopy imaging and nano-tomography. We directly observe a close correlation between surface chemistry and phase distribution from homogeneity to heterogeneity, which induces heterogeneous internal strain within the particle and the resulting structural/performance degradation during cycling. We also discover that surface chemistry can significantly enhance the cyclic performance. Our modified process effectively regulates the performance fade issue of single-crystal cathode and provides new insights for improved design of high-capacity battery materials.
Engineering unsymmetrically coordinated Cu-S1N3 single atom sites with enhanced oxygen reduction activity
Authors: Shang Huishan , Zhou Xiangyi , Dong Juncai , Li Ang , Zhao Xu , Liu Qinghua , Lin Yue , Pei Jiajing , Li Zhi , Jiang Zhuoli , Zhou Danni , Zheng Lirong , Wang Yu , Zhou Jing , Yang Zhengkun , Cao Rui , Sarangi Ritimukta , Sun Tingting , Yang Xin , Zheng Xusheng , Yan Wensheng , Zhuang Zhongbin , Li Jia , Chen Wenxing , Wang Dingsheng , Zhang Jiatao , Li Yadong
Published: June 2020

Atomic interface regulation is thought to be an efficient method to adjust the performance of single atom catalysts. Herein, a practical strategy was reported to rationally design single copper atoms coordinated with both sulfur and nitrogen atoms in metal-organic framework derived hierarchically porous carbon (S-Cu-ISA/SNC). The atomic interface configuration of the copper site in S-Cu-ISA/SNC is detected to be an unsymmetrically arranged Cu-S1N3 moiety. The catalyst exhibits excellent oxygen reduction reaction activity with a half-wave potential of 0.918 V vs. RHE. Additionally, through in situ X-ray absorption fine structure tests, we discover that the low-valent Cuprous-S1N3 moiety acts as an active center during the oxygen reduction process. Our discovery provides a universal scheme for the controllable synthesis and performance regulation of single metal atom catalysts toward energy applications.
Evolution from unimolecular to colloidal-quantum-dot-like character in chlorine or zinc incorporated InP magic size clusters
Authors: Kwon Yongju , Oh Juwon , Lee Eunjae , Lee Sang Hyeon , Agnes Anastasia , Bang Gyuhyun , Kim Jeongmin , Kim Dongho , Kim Sungjee
Published: June 2020

Magic-sized clusters (MSCs) can be isolated as intermediates in quantum dot (QD) synthesis, and they provide pivotal clues in understanding QD growth mechanisms. We report syntheses for two families of heterogeneous-atom-incorporated InP MSCs that have chlorine or zinc atoms. All the MSCs could be directly synthesized from conventional molecular precursors. Alternatively, each series of MSCs could be prepared by sequential conversions. 386-InP MSCs could be converted to F360-InP:Cl MSCs, then to F399-InP:Cl MSCs. Similarly, F360-InP:Zn MSCs could be converted to F408-InP:Zn MSCs, then to F393-InP:Zn MSCs. As the conversion proceeded, evolution from uni-molecule-like to QD-like characters was observed. Early stage MSCs showed active inter-state conversions in the excited states, which is characteristics of small molecules. Later stage MSCs exhibited narrow photoinduced absorptions at lower-energy region like QDs. The crystal structure also gradually evolved from polytwistane to more zinc-blende.
Topological framework for directional amplification in driven-dissipative cavity arrays
Authors: Wanjura Clara C. , Brunelli Matteo , Nunnenkamp Andreas
Published: June 2020

Directional amplification, in which signals are selectively amplified depending on their propagation direction, has attracted much attention as key resource for applications, including quantum information processing. Recently, several, physically very different, directional amplifiers have been proposed and realized in the lab. In this work, we present a unifying framework based on topology to understand non-reciprocity and directional amplification in driven-dissipative cavity arrays. Specifically, we unveil a one-to-one correspondence between a non-zero topological invariant defined on the spectrum of the dynamic matrix and regimes of directional amplification, in which the end-to-end gain grows exponentially with the number of cavities. We compute analytically the scattering matrix, the gain and reverse gain, showing their explicit dependence on the value of the topological invariant. Parameter regimes achieving directional amplification can be elegantly obtained from a topological ‘phase diagram’, which provides a guiding principle for the design of both phase-preserving and phase-sensitive multimode directional amplifiers.
Diauxie and co-utilization of carbon sources can coexist during bacterial growth in nutritionally complex environments
Authors: Perrin Elena , Ghini Veronica , Giovannini Michele , Di Patti Francesca , Cardazzo Barbara , Carraro Lisa , Fagorzi Camilla , Turano Paola , Fani Renato , Fondi Marco
Published: June 2020

It is commonly thought that when multiple carbon sources are available, bacteria metabolize them either sequentially (diauxic growth) or simultaneously (co-utilization). However, this view is mainly based on analyses in relatively simple laboratory settings. Here we show that a heterotrophic marine bacterium, Pseudoalteromonas haloplanktis, can use both strategies simultaneously when multiple possible nutrients are provided in the same growth experiment. The order of nutrient uptake is partially determined by the biomass yield that can be achieved when the same compounds are provided as single carbon sources. Using transcriptomics and time-resolved intracellular 1H-13C NMR, we reveal specific pathways for utilization of various amino acids. Finally, theoretical modelling indicates that this metabolic phenotype, combining diauxie and co-utilization of substrates, is compatible with a tight regulation that allows the modulation of assimilatory pathways.
Strain-induced room-temperature ferroelectricity in SrTiO3 membranes
Authors: Xu Ruijuan , Huang Jiawei , Barnard Edward S. , Hong Seung Sae , Singh Prastuti , Wong Ed K. , Jansen Thies , Harbola Varun , Xiao Jun , Wang Bai Yang , Crossley Sam , Lu Di , Liu Shi , Hwang Harold Y.
Published: June 2020

Advances in complex oxide heteroepitaxy have highlighted the enormous potential of utilizing strain engineering via lattice mismatch to control ferroelectricity in thin-film heterostructures. This approach, however, lacks the ability to produce large and continuously variable strain states, thus limiting the potential for designing and tuning the desired properties of ferroelectric films. Here, we observe and explore dynamic strain-induced ferroelectricity in SrTiO3 by laminating freestanding oxide films onto a stretchable polymer substrate. Using a combination of scanning probe microscopy, optical second harmonic generation measurements, and atomistic modeling, we demonstrate robust room-temperature ferroelectricity in SrTiO3 with 2.0% uniaxial tensile strain, corroborated by the notable features of 180° ferroelectric domains and an extrapolated transition temperature of 400 K. Our work reveals the enormous potential of employing oxide membranes to create and enhance ferroelectricity in environmentally benign lead-free oxides, which hold great promise for applications ranging from non-volatile memories and microwave electronics.
Establishing the carrier scattering phase diagram for ZrNiSn-based half-Heusler thermoelectric materials
Authors: Ren Qingyong , Fu Chenguang , Qiu Qinyi , Dai Shengnan , Liu Zheyuan , Masuda Takatsugu , Asai Shinichiro , Hagihala Masato , Lee Sanghyun , Torri Shuki , Kamiyama Takashi , He Lunhua , Tong Xin , Felser Claudia , Singh David J. , Zhu Tiejun , Yang Jiong , Ma Jie
Published: June 2020

Chemical doping is one of the most important strategies for tuning electrical properties of semiconductors, particularly thermoelectric materials. Generally, the main role of chemical doping lies in optimizing the carrier concentration, but there can potentially be other important effects. Here, we show that chemical doping plays multiple roles for both electron and phonon transport properties in half-Heusler thermoelectric materials. With ZrNiSn-based half-Heusler materials as an example, we use high-quality single and polycrystalline crystals, various probes, including electrical transport measurements, inelastic neutron scattering measurement, and first-principles calculations, to investigate the underlying electron-phonon interaction. We find that chemical doping brings strong screening effects to ionized impurities, grain boundary, and polar optical phonon scattering, but has negligible influence on lattice thermal conductivity. Furthermore, it is possible to establish a carrier scattering phase diagram, which can be used to select reasonable strategies for optimization of the thermoelectric performance.
Genome-wide analysis in the mouse embryo reveals the importance of DNA methylation for transcription integrity
Authors: Dahlet Thomas , Argüeso Lleida Andrea , Al Adhami Hala , Dumas Michael , Bender Ambre , Ngondo Richard P. , Tanguy Manon , Vallet Judith , Auclair Ghislain , Bardet Anaïs F. , Weber Michael
Published: June 2020

Mouse embryos acquire global DNA methylation of their genome during implantation. However the exact roles of DNA methyltransferases (DNMTs) in embryos have not been studied comprehensively. Here we systematically analyze the consequences of genetic inactivation of Dnmt1, Dnmt3a and Dnmt3b on the methylome and transcriptome of mouse embryos. We find a strict division of function between DNMT1, responsible for maintenance methylation, and DNMT3A/B, solely responsible for methylation acquisition in development. By analyzing severely hypomethylated embryos, we uncover multiple functions of DNA methylation that is used as a mechanism of repression for a panel of genes including not only imprinted and germline genes, but also lineage-committed genes and 2-cell genes. DNA methylation also suppresses multiple retrotransposons and illegitimate transcripts from cryptic promoters in transposons and gene bodies. Our work provides a thorough analysis of the roles of DNA methyltransferases and the importance of DNA methylation for transcriptome integrity in mammalian embryos.
Deconstructing sarcomeric structure–function relations in titin-BioID knock-in mice
Authors: Rudolph Franziska , Fink Claudia , Hüttemeister Judith , Kirchner Marieluise , Radke Michael H. , Lopez Carballo Jacobo , Wagner Eva , Kohl Tobias , Lehnart Stephan E. , Mertins Philipp , Gotthardt Michael
Published: June 2020

Proximity proteomics has greatly advanced the analysis of native protein complexes and subcellular structures in culture, but has not been amenable to study development and disease in vivo. Here, we have generated a knock-in mouse with the biotin ligase (BioID) inserted at titin’s Z-disc region to identify protein networks that connect the sarcomere to signal transduction and metabolism. Our census of the sarcomeric proteome from neonatal to adult heart and quadriceps reveals how perinatal signaling, protein homeostasis and the shift to adult energy metabolism shape the properties of striated muscle cells. Mapping biotinylation sites to sarcomere structures refines our understanding of myofilament dynamics and supports the hypothesis that myosin filaments penetrate Z-discs to dampen contraction. Extending this proof of concept study to BioID fusion proteins generated with Crispr/CAS9 in animal models recapitulating human pathology will facilitate the future analysis of molecular machines and signaling hubs in physiological, pharmacological, and disease context.