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Older female mice lacking triggering recepter expressed on myeloid cells-2 have worse post-stroke neurological function and enhanced pro-inflammatory responses
A Theory of Anisotropic Semiconductor of Heavy Fermions
It is demonstrated that a {\veck}-dependence of the hybridization matrix
element between - and conduction electrons can give rise to an anisotropic
hybridization gap of heavy fermions if the filling of electrons corresponds to
that of the band insulator. The most interesting case occurs when the
hybridization vanishes along some symmetry axis of the crystal reflecting a
particular symmetry of the crystal field. The results of a model calculation
are consistent with wide range of anomalous properties observed in CeNiSn and
its isostructural compounds, the anisotropic semiconductor of heavy fermions.
In particular, highly sensitive effect of impurity scattering on the residual
density of states for zero energy excitation and the anisotropic temperature
dependence of the resistivity are well explained. It is also discussed that a
weak semimetallic behavior arises through the weak \veck-dependence of the
-electron self-energy \Sigma_{f}(\veck,0).Comment: 21 pages, LaTeX (JPSJ style file) and 13 postscript figures, To
appear in J. Phys. Soc. Jp
Iron (Fe) speciation in size-fractionated aerosol particles in the Pacific Ocean: The role of organic complexation of Fe with humic-like substances in controlling Fe solubility
Atmospheric deposition is one of the main sources of dissolved iron (Fe) in
the ocean surfaces. Atmospheric processes are recognized as controlling
fractional Fe solubility (Fesol%) in marine aerosol particles.
However, the impact of these processes on Fesol% remains unclear.
One of the reasons for this is the lack of field observations focusing on
the relationship between Fesol% and Fe species in marine aerosol
particles. In particular, the effects of organic ligands on Fesol%
have not been thoroughly investigated in observational studies. In this
study, Fe species in size-fractionated aerosol particles in the Pacific
Ocean were determined using X-ray absorption fine structure (XAFS)
spectroscopy. The internal mixing states of Fe and organic carbon were
investigated using scanning transmission X-ray microscopy (STXM). The
effects of atmospheric processes on Fesol% in marine aerosol
particles were investigated based on the speciation results. Iron in
size-fractionated aerosol particles was mainly derived from mineral dust,
regardless of aerosol diameter, because the enrichment factor of Fe was
almost 1 in both coarse (PM>1.3) and fine aerosol particles
(PM1.3). Approximately 80 % of the total Fe (insoluble + labile
Fe) was present in PM>1.3, whereas labile Fe was mainly present in
PM1.3. The Fesol% in PM>1.3 was not significantly
increased (2.56±2.53 %, 0.00 %–8.50 %, n=20) by the
atmospheric processes because mineral dust was not acidified beyond the
buffer capacity of calcite. In contrast, mineral dust in PM1.3 was
acidified beyond the buffer capacity of calcite. As a result, Fesol%
in PM1.3 (0.202 %–64.7 %, n=10) was an order of magnitude higher
than that in PM>1.3. The PM1.3 contained ferric organic complexes
with humic-like substances (Fe(III)-HULIS, but not Fe-oxalate complexes),
and the abundance correlated with Fesol%. Iron(III)-HULIS was formed
during transport in the Pacific Ocean because Fe(III)-HULIS was not found in
aerosol particles in Beijing and Japan. The pH estimations of mineral dust
in PM1.3 established that Fe was solubilized by proton-promoted
dissolution under highly acidic conditions (pH < 3.0), whereas
Fe(III)-HULIS was stabilized under moderately acidic conditions (pH 3.0–6.0). Since the observed labile Fe concentration could not be
reproduced by proton-promoted dissolution under moderately acidic
conditions, the pH of mineral dust increased after proton-promoted
dissolution. The cloud process in the marine atmosphere increases the
mineral dust pH because the dust particles are covered with organic carbon
and Na. The precipitation of ferrihydrite was suppressed by Fe(III)-HULIS
owing to its high water solubility. Thus, the organic complexation of Fe
with HULIS plays a significant role in the stabilization of Fe that was
initially solubilized by proton-promoted dissolution.</p
Measurement report: Stoichiometry of dissolved iron and aluminum as an indicator of the factors controlling the fractional solubility of aerosol iron – results of the annual observations of size-fractionated aerosol particles in Japan
The atmospheric deposition of iron (Fe) promotes primary production in the
surface ocean, which results in the enhanced uptake of carbon dioxide into
surface seawater. Given that microorganisms in seawater utilize dissolved Fe
(d-Fe) as a nutrient, the bioavailability of Fe in aerosol particles depends
on its solubility. However, the factors controlling fractional Fe solubility
(Fesol %) in aerosol particles have not been fully understood. This
study performed annual observations of the total and dissolved metal
concentrations in size-fractionated (seven fractions) aerosol particles at
Higashi-Hiroshima, Japan. The feasibility of the molar concentration ratio
of d-Fe relative to dissolved Al ([d-Fe] / [d-Al]) as an indicator of sources
of d-Fe in aerosol particles was investigated because this ratio is likely
dependent on the emission sources of Fe (e.g., mineral dust, fly ash, and
anthropogenic Fe oxides) and their dissolution processes (proton- and
ligand-promoted dissolutions). Approximately 70 % of the total Fe in
total suspended particulates (TSPs) was present in coarse aerosol particles,
whereas about 70 % of d-Fe in TSPs was mainly found in fine aerosol
particles. The average Fesol % in fine aerosol particles (11.4 ± 7.0 %) was higher than that of coarse aerosol particles (2.19 ± 2.27 %). In addition, the average ratio of [d-Fe] / [d-Al] in coarse
aerosol particles (0.408 ± 0.168) was lower than that in fine aerosol
particles (1.15 ± 0.80). The range of [d-Fe] / [d-Al] ratios in the
coarse aerosol particles (0.121–0.927) was similar to that obtained by
proton-promoted dissolution of mineral dust (0.1–1.0), which indicates that
the d-Fe in coarse aerosol particles was derived from mineral dust. The
[d-Fe] / [d-Al] ratios of fine aerosol particles ranged from 0.386 to 4.67,
and [d-Fe] / [d-Al] ratios greater than 1.50 cannot be explained by proton-
and ligand-promoted dissolutions (1.00 < [d-Fe] / [d-Al] < 1.50). The [d-Fe] / [d-Al] ratio correlated with the enrichment factor of Fe
in fine aerosol particles (r: 0.505), which indicates that anthropogenic Fe
with a high [d-Fe] / [d-Al] ratio was the source of d-Fe in fine aerosol
particles. The high [d-Fe] / [d-Al] ratio was attributed to anthropogenic Fe
oxides emitted from high-temperature combustions. Finally, the fraction of
anthropogenic Fe oxides to d-Fe in TSPs was
calculated based on the [d-Fe] / [d-Al] ratio of aerosols and their emission
source samples. As a result, the fraction of anthropogenic Fe oxides to d-Fe
in TSPs varied from 1.48 % to 80.7 %. A high fraction was observed in
summer when air masses originated from industrial regions in Japan. By
contrast, approximately 10 % of d-Fe in the TSPs collected in
spring and during Asian dust events was derived from anthropogenic Fe oxides
when air masses were frequently transported from East Asia to the Pacific Ocean.
Thus, mineral dust was the dominant source of d-Fe in Asian outflow to the
Pacific Ocean.</p
Dobutamine stress echocardiography for assessing the role of dynamic intraventricular obstruction in left ventricular ballooning syndrome
<p>Abstract</p> <p>Background</p> <p>Dynamic intraventricular obstruction has been observed in patients with left ventricular ballooning syndrome (LVBS) and has been hypothesized as a possible mechanism of the syndrome. The aim of this study was to assess the prevalence and significance of dynamic intraventricular obstruction in patients with LVBS.</p> <p>Methods and Results</p> <p>Dobutamine stress echocardiography was carried out in 22 patients with LVBS (82% apical), all women, aged 68 ± 9 years. At baseline 1 patient had a > 30 mmHg LV gradient; during stress a LV gradient > 30 mm Hg developed in 6/21 patients (28%) and was caused by systolic anterior motion of the mitral valve in the 3 patients with severe gradient (mean 116 ± 29 mmHg), who developed mitral regurgitation and impaired apical wall motion and by obstruction at mid-ventricular level in the other 3 with a moderate gradient (mean 46 ± 16 mmHg). Compared with patients without obstruction those with obstruction had a greater mean septal thickness (11.6 ± .6 vs 9.8. ± 3, p < .01), a higher prevalence of septal hypertrophy (71% vs 7%, p < .005) and a higher peak wall motion score index (1.62 ± .4 vs 1.08 ± .4, p < .01).</p> <p>Conclusion</p> <p>Spontaneous or dobutamine-induced dynamic LV obstruction is documented in 32% of patients with LVBS, is correlated with the presence of septal hypertrophy and may play a role in the development of LVBS in this subset of patients. In those without septal hypertrophy a dynamic obstruction is rarely induced with dobutamine and is unlikely to be a major pathogenetic factor of the syndrome.</p
Lectin-like bacteriocins from pseudomonas spp. utilise D-rhamnose containing lipopolysaccharide as a cellular receptor
Lectin-like bacteriocins consist of tandem monocot mannose-binding domains and display a genus-specific killing activity. Here we show that pyocin L1, a novel member of this family from Pseudomonas aeruginosa, targets susceptible strains of this species through recognition of the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide that is predominantly a homopolymer of d-rhamnose. Structural and biophysical analyses show that recognition of CPA occurs through the C-terminal carbohydrate-binding domain of pyocin L1 and that this interaction is a prerequisite for bactericidal activity. Further to this, we show that the previously described lectin-like bacteriocin putidacin L1 shows a similar carbohydrate-binding specificity, indicating that oligosaccharides containing d-rhamnose and not d-mannose, as was previously thought, are the physiologically relevant ligands for this group of bacteriocins. The widespread inclusion of d-rhamnose in the lipopolysaccharide of members of the genus Pseudomonas explains the unusual genus-specific activity of the lectin-like bacteriocins
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