3,249 research outputs found
Specific heat study of the Na(0.3)CoO(2).1.3H(2)O superconductor: influence of the complex chemistry
We report results of specific heat measurements on polycrystalline samples of
the layered superconductor, Na(0.3)CoO(2).1.3H(2)O. The electronic contribution
to the specific heat, gamma, is found to be 12.2 mJ/mol-K2. The feature at the
superconducting transition is rather sharp, becoming broad and strongly
suppressed in an applied magnetic field. The data indicate a residual normal
state electronic specific heat at low temperatures, implying that there is a
sizable population of normal state electrons in the samples even below Tc.
Inhomogeneity in the Na content, to which the superconducting state is
exquisitely sensitive, appears to be the most likely explanation for these
results. These results further indicate that special sample handling is
required for an accurate characterization of the superconducting state in this
material.Comment: publication information adde
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Influence of biosurfactants on mass transfer, biodegradation, and transport of mixed wastes in multiphase systems: Final report
The overall results of this project suggest that is situ treatment with biosurfactants has the potential to be an effective,economical, and nontoxic remediation technology. Specifically, we have demonstrated that a rhamnolipid biosurfactant may be used to increase the apparent solubility and biodegradation rate of organic compounds
Chemical Instability of the Cobalt Oxyhydrate Superconductor under Ambient Conditions
The layered sodium cobalt oxyhydrate superconductor Na0.3CoO2*1.4H2O is shown
through X-ray diffraction and thermogravimetric studies to be one of a series
of hydrated phases of Na0.3CoO2. Further, it is shown that the material is
exceptionally sensitive to both temperature and humidity near ambient
conditions, easily dehydrating to a non-superconducting lower hydrate. The
observation of this stable lower hydrate with c=13.8 angstroms implies that the
superconductivity turns on in this system between CoO2 layer spacings of 6.9
and 9.9 angstroms at nominally constant chemical doping.Comment: 10 pages and 4 figure
Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA
We report results of air monitoring started due to the recent natural
catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the
Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered
the first arrival of the airborne fission products 131-I, 132-I, 132-Te,
134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic
gamma rays using a germanium detector. We measured the evolution of the
activities over a period of 23 days at the end of which the activities had
mostly fallen below our detection limit. The highest detected activity amounted
to 4.4 +/- 1.3 mBq/m^3 of 131-I on 19-20 March.Comment: 7 pages, 5 figures, published in Journal of Environmental
Radioactivit
Extracellular vesicles in acute respiratory distress syndrome: Understanding protective and harmful signaling for the development of new therapeutics
Acute respiratory distress syndrome (ARDS)
is a severe respiratory condition characterized by
increased lung permeability, hyper-inflammatory state,
and fluid leak into the alveolar spaces. ARDS is a
heterogeneous disease, with multiple direct and indirect
causes that result in a mortality of up to 40%. Due to the
ongoing Covid-19 pandemic, its incidence has increased
up to ten-fold. Extracellular vesicles (EVs) are small
liposome-like particles that mediate intercellular
communication and play a major role in ARDS
pathophysiology. Indeed, they participate in endothelial
barrier dysfunction and permeability, neutrophil, and
macrophage activation, and also in the development of a
hypercoagulable state. A more thorough understanding
of the variegated and cell-specific functions of EVs may
lead to the development of safe and effective
therapeutics. In this review, we have collected evidence
of EVs role in ARDS, revise the main mechanisms of
production and internalization and summarize the
current therapeutical approaches that have shown the
ability to modulate EV signaling
Short communication: Phenotypic and genetic diversity of wild Lactococcus lactis isolated from traditional Pecorino cheeses of Tuscany
Wild Lactococcus lactis isolates from traditional Pecorino cheeses in 4 regions of Tuscany were isolated and characterized to evaluate the diversity of autochthonous lactococci. Sixty strains of Lactococcus were clustered by the results of carbohydrate utilization and diagnostic enzyme activity. Twenty-one unique strains were then chosen for characterization of salt and temperature tolerance, as well as acidification and proteolytic activity in milk. Genetic analysis of these strains was performed via 16S ribosomal DNA sequencing and multilocus sequence typing (MLST) to elucidate diversity relative to their location of origin. Phylogenetic analysis showed distinct clustering by region within organism subspecies, and phenotypic properties demonstrated concomitant trends. Multilocus sequence typing thus allowed for the regional distinction of isolates separate from those of previous works, supporting the concept that distinctive regional qualities of cheeses are strongly influenced by microbial ecology
Nested Codes for Constrained Memory and for Dirty Paper
Dirty paper coding are relevant for wireless networks, multiuser channels, and digital watermarking. We show that the problem of dirty paper is essentially equivalent to some classes of constrained memories, and we explore the binary so-called nested codes, which are used for efficient coding and error-correction on such channels and memories. © Springer-Verlag Berlin Heidelberg 2006
Study on initial geometry fluctuations via participant plane correlations in heavy ion collisions: part II
Further investigation of the participant plane correlations within a Glauber
model framework is presented, focusing on correlations between three or four
participant planes of different order. A strong correlation is observed for
which is a reflection of the
elliptic shape of the overlap region. The correlation between the corresponding
experimental reaction plane angles can be easily measured. Strong correlations
of similar geometric origin are also observed for
,
,
,
,
, and
, which are also measurable.
Experimental measurements of the corresponding reaction plane correlators in
heavy ion collisions at RHIC and the LHC may improve our understanding of the
physics underlying the measured higher order flow harmonics.Comment: 5 pages, 5 figure
Influence of temperature gradients on tunnel junction thermometry below 1 K: cooling and electron-phonon coupling
We have studied thermal gradients in thin Cu and AlMn wires, both
experimentally and theoretically. In the experiments, the wires were Joule
heated non-uniformly at sub-Kelvin temperatures, and the resulting temperature
gradients were measured using normal metal-insulator-superconducting tunnel
junctions. The data clearly shows that even in reasonably well conducting thin
wires with a short (m) non-heated portion, significant temperature
differences can form. In most cases, the measurements agree well with a model
which includes electron-phonon interaction and electronic thermal conductivity
by the Wiedemann-Franz law.Comment: J. Low Temp. Phys. in pres
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