1,761 research outputs found
Tissue eosinophilia and eosinophil degranulation in Riedel's invasive fibrous thyroiditis.
The etiology of Riedel's invasive fibrous thyroiditis (IFT) has remained obscure. This rare disorder has been confused in the past with the more common fibrous variant of Hashimoto's disease. The typical histological features of IFT, in particular the presence of an invasive fibrosclerotic process in conjunction with a prominent chronic inflammatory infiltrate, suggest that the release of fibrogenic cytokines and other factors from these cellular infiltrates may play an important role in the pathogenesis of this condition. Our observations in routinely processed tissue sections obtained from patients with documented IFT of striking tissue eosinophilia led us to hypothesize that eosinophils and their products may play a role in the evolution of this disease. Immunofluorescence staining with affinity-purified polyclonal rabbit antibody directed against human eosinophil granule major basic protein revealed marked tissue eosinophilia and abundant extracellular deposition of major basic protein in all specimens from 16 patients with IFT. By contrast, only occasional eosinophils and no extracellular major basic protein were detected in control thyroid tissues obtained from patients with multinodular goiter, Graves' disease, Hashimoto's disease, and normal thyroid tissue. The presence of marked eosinophil infiltration and extracellular major basic protein deposition in IFT and other associated fibrosclerotic conditions suggests a role for eosinophils and their products in propagating the fibrogenesis seen in IFT
Analysis of testbed airborne multispectral scanner data from Superflux II
A test bed aircraft multispectral scanner (TBAMS) was flown during the James Shelf, Plume Scan, and Chesapeake Bay missions as part of the Superflux 2 experiment. Excellent correlations were obtained between water sample measurements of chlorophyll and sediment and TBAMS radiance data. The three-band algorithms used were insensitive to aircraft altitude and varying atmospheric conditions. This was particularly fortunate due to the hazy conditions during most of the experiments. A contour map of sediment, and also chlorophyll, was derived for the Chesapeake Bay plume along the southern Virginia-Carolina coastline. A sediment maximum occurs about 5 nautical miles off the Virginia Beach coast with a chlorophyll maximum slightly shoreward of this. During the James Shelf mission, a thermal anomaly (or front) was encountered about 50 miles from the coast. There was a minor variation in chlorophyll and sediment across the boundary. During the Chesapeake Bay mission, the Sun elevation increased from 50 degrees to over 70 degrees, interfering with the generation of data products
Partly Occupied Wannier Functions
We introduce a scheme for constructing partly occupied, maximally localized
Wannier functions (WFs) for both molecular and periodic systems. Compared to
the traditional occupied WFs the partly occupied WFs posses improved symmetry
and localization properties achieved through a bonding-antibonding closing
procedure. We demonstrate the equivalence between bonding-antibonding closure
and the minimization of the average spread of the WFs in the case of a benzene
molecule and a linear chain of Pt atoms. The general applicability of the
method is demonstrated through the calculation of WFs for a metallic system
with an impurity: a Pt wire with a hydrogen molecular bridge.Comment: 5 pages, 4 figure
Identification of proteomic signatures associated with depression and psychotic depression in post-mortem brains from major depression patients
Major depressive disorder (MDD) is a leading cause of disability worldwide and results tragically in the loss of almost one million lives in Western societies every year. This is due to poor understanding of the disease pathophysiology and lack of empirical medical tests for accurate diagnosis or for guiding antidepressant treatment strategies. Here, we have used shotgun proteomics in the analysis of post-mortem dorsolateral prefrontal cortex brain tissue from 24 MDD patients and 12 matched controls. Brain proteomes were pre-fractionated by gel electrophoresis and further analyzed by shotgun data-independent label-free liquid chromatography-mass spectrometry. This led to identification of distinct proteome fingerprints between MDD and control subjects. Some of these differences were validated by Western blot or selected reaction monitoring mass spectrometry. This included proteins associated with energy metabolism and synaptic function and we also found changes in the histidine triad nucleotide-binding protein 1 (HINT1), which has been implicated recently in regulation of mood and behavior. We also found differential proteome profiles in MDD with (n=11) and without (n=12) psychosis. Interestingly, the psychosis fingerprint showed a marked overlap to changes seen in the brain proteome of schizophrenia patients. These findings suggest that it may be possible to contribute to the disease understanding by distinguishing different subtypes of MDD based on distinct brain proteomic profiles
Mathematical Model of Easter Island Society Collapse
In this paper we consider a mathematical model for the evolution and collapse
of the Easter Island society, starting from the fifth century until the last
period of the society collapse (fifteen century). Based on historical reports,
the available primary sources consisted almost exclusively on the trees. We
describe the inhabitants and the resources as an isolated system and both
considered as dynamic variables. A mathematical analysis about why the
structure of the Easter Island community collapse is performed. In particular,
we analyze the critical values of the fundamental parameters driving the
interaction humans-environment and consequently leading to the collapse. The
technological parameter, quantifying the exploitation of the resources, is
calculated and applied to the case of other extinguished civilization (Cop\'an
Maya) confirming, with a sufficiently precise estimation, the consistency of
the adopted model.Comment: 9 pages, 1 figure, final version published on EuroPhysics Letter
The role of structural evolution on the quantum conductance behavior of gold nanowires during stretching
Gold nanowires generated by mechanical stretching have been shown to adopt
only three kinds of configurations where their atomic arrangements adjust such
that either the [100], [111] or [110] zone axes lie parallel to the elongation
direction. We have analyzed the relationship between structural rearrangements
and electronic transport behavior during the elongation of Au nanowires for
each of the three possibilities. We have used two independent experiments to
tackle this problem, high resolution transmission high resolution electron
microscopy to observe the atomic structure and a mechanically controlled break
junction to measure the transport properties. We have estimated the conductance
of nanowires using a theoretical method based on the extended H\"uckel theory
that takes into account the atom species and their positions. Aided by these
calculations, we have consistently connected both sets of experimental results
and modeled the evolution process of gold nanowires whose conductance lies
within the first and third conductance quanta. We have also presented evidence
that carbon acts as a contaminant, lowering the conductance of one-atom-thick
wires.Comment: 10 page
Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping
We address one of the main challenges to TiO2-photocatalysis, namely band gap
narrowing, by combining nanostructural changes with doping. With this aim we
compare TiO2's electronic properties for small 0D clusters, 1D nanorods and
nanotubes, 2D layers, and 3D surface and bulk phases using different
approximations within density functional theory and GW calculations. In
particular, we propose very small (R < 0.5 nm) but surprisingly stable
nanotubes with promising properties. The nanotubes are initially formed from
TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing
to a rutile nanorod structure. We find that quantum confinement effects - as
expected - generally lead to a widening of the energy gap. However,
substitutional doping with boron or nitrogen is found to give rise to
(meta-)stable structures and the introduction of dopant and mid-gap states
which effectively reduce the band gap. Boron is seen to always give rise to
n-type doping while depending on the local bonding geometry, nitrogen may give
rise to n-type or p-type doping. For under coordinated TiO2 surface structures
found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise
to acceptor states while for larger clusters and bulk structures donor states
are introduced
Effects of climate extremes on the terrestrial carbon cycle : concepts, processes and potential future impacts
This article is protected by copyright. All rights reserved. Acknowledgements This work emerged from the CARBO-Extreme project, funded by the European Community’s 7th framework programme under grant agreement (FP7-ENV-2008-1-226701). We are grateful to the Reviewers and the Subject Editor for helpful guidance. We thank to Silvana Schott for graphic support. Mirco Miglivacca provided helpful comments on the manuscript. Michael Bahn acknowledges support from the Austrian Science Fund (FWF; P22214-B17). Sara Vicca is a postdoctoral research associate of the Fund for Scientific Research – Flanders. Wolfgang Cramer contributes to the Labex OT-Med (n° ANR-11- LABX-0061) funded by the French government through the A*MIDEX project (n° ANR-11-IDEX-0001-02). Flurin Babst acknowledges support from the Swiss National Science Foundation (P300P2_154543).Peer reviewedPublisher PD
Magnetic phenomena in 5d transition metal nanowires
We have carried out fully relativistic full-potential, spin-polarized,
all-electron density-functional calculations for straight, monatomic nanowires
of the 5d transition and noble metals Os, Ir, Pt and Au. We find that, of these
metal nanowires, Os and Pt have mean-field magnetic moments for values of the
bond length at equilibrium. In the case of Au and Ir, the wires need to be
slightly stretched in order to spin polarize. An analysis of the band
structures of the wires indicate that the superparamagnetic state that our
calculations suggest will affect the conductance through the wires -- though
not by a large amount -- at least in the absence of magnetic domain walls. It
should thus lead to a characteristic temperature- and field dependent
conductance, and may also cause a significant spin polarization of the
transmitted current.Comment: 7 pages, 5 figure
Overcoming cross-cultural group work tensions: mixed student perspectives on the role of social relationships
As universities worldwide rapidly internationalise, higher education classrooms have become unique spaces for collaboration between students from different countries. One common way to encourage collaboration between diverse peers is through group work. However, previous research has highlighted that cross-cultural group work can be challenging and has hinted at potential social tensions. To understand this notion better, we have used robust quantitative tools in this study to select 20 participants from a larger classroom of 860 students to take part in an in-depth qualitative interview about cross-cultural group work experiences. Participant views on social tensions in cross-cultural group work were elicited using a unique mediating artefact method to encourage reflection and in-depth discussion. In our analysis of emergent interview themes, we compared student perspectives on the role of social relationships in group work by their academic performance level. Our findings indicated that all students interviewed desired the opportunity to form social relationships with their group work members, but their motivations for doing so varied widely by academic performance level
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