893 research outputs found
Pulmonary hypertension in infants with congenital heart defects: are leukotrienes involved?
The circulating levels of leukotriene E4 in infants with congenital heart defects, increased pulmonary blood flow and pulmonary arterial hypertension, were determined and compared with infants with decreased pulmonary blood flow (Tetralogy of Fallot). There was no correlation (r=0.38) between the pulmonary arterial pressure
(56 ± 4 mmHg) and the leukotriene E4 levels (1.37 ± 0.67 ng/ml blood) measured in peripheral blood samples from the hypertensive group prior to surgery. There was considerable variation in the detectable leukotriene E4 levels in blood samples from different patients. The levels detected in the blood samples between the two groups of patients was similar. These data suggest that neither the surgical repair during cardiopulmonary bypass nor the pulmonary hypertension appeared to modify the leukotriene E4 blood levels in the small number of patients studied
Іван Франко - публіцист
Проаналізовано соціально-економічну і культурно-освітню публіцистику І. Франка,
зокрема, його ставлення до податкової політики Австро-Угорщини, діяльності
банківської системи, еміграції з Галичини, кооперативного руху, майбутнього
української держави.The article analyses social and economic and cultural and educational publications by Ivan
Franko, as well as his attitude to tax policies in Austro-Hungarian Empire, banking system
activities, emigration from Halychyna, co-operative societies movement, and the future of
Ukraine
Anti-IgE Response in Human Airways: Relative Contribution of Inflammatory Mediators
Heman airway preparations at resting tone were relaxed with either
the leukotriene synthesis inhibitor BAY x1005 (3 μM),
chlorpheniramine (1 μM) or the thromboxane receptor antagonist
BAY u3405 (0.1 μM). The response to anti-IgE (1:1000) was 58
± 8% of acetylcholine pre-contraction (2.19 ±
0.28 g). Indomethacin (3 μM) enhanced the anti-IgE-induced
contraction by 28%. The anti-IgE maximal response was not
modified by either chlorpheniramine, BAY x1005 or BAY u3405. When
the tissues were treated with either BAY xl005/indomethacin or
BAY x1005/chlorpheniramine, the anti-IgE-induced contraction was
reduced. In addition, in presence of BAY
xl005/indomethacin/chlorpheniramine the response was
completely blocked. These results suggest that mediatots released
during anti-IgE challenge cause airway contraction which may mask
the evaluation of the leukotriene component
Modeling emission features of salicylidene aniline molecular crystals: A QM/QM' approach
A new computational protocol relying on the use of electrostatic embedding, derived from QM/QM' ONIOM calculations, to simulate the effect of the crystalline environment on the emission spectra of molecular crystals is here applied to the beta-form of salicylidene aniline (SA). The first singlet excited states (S-1) of the SA cis-keto and trans-keto conformers, surrounded by a cluster of other molecules representing the crystalline structure, were optimized by using a QM/QM' ONIOM approach with and without electronic embedding. The model system consisting of the central salicylidene aniline molecule was treated at the DFT level by using either the B3LYP, PBE0, or the CAM-B3LYP functional, whereas the real system was treated at the HF level. The CAM-B3LYP/HF level of theory provides emission energies in good agreement with experiment with differences of 220/232 nm (cis-keto form) and 28/214 nm (trans-keto form), respectively, whereas notably larger differences are obtained using global hybrids. Though such differences on the optical properties arise from the density functional choice, the contribution of the electronic embedding is rather independent of the functional used. This plays in favor of a more general applicability of the present protocol to other crystalline molecular systems
Resonant Lifetime of Core-Excited Organic Adsorbates from First Principles
We investigate by first-principles simulations the resonant electron-transfer
lifetime from the excited state of an organic adsorbate to a semiconductor
surface, namely isonicotinic acid on rutile TiO(110). The
molecule-substrate interaction is described using density functional theory,
while the effect of a truly semi-infinite substrate is taken into account by
Green's function techniques. Excitonic effects due to the presence of
core-excited atoms in the molecule are shown to be instrumental to understand
the electron-transfer times measured using the so-called core-hole-clock
technique. In particular, for the isonicotinic acid on TiO(110), we find
that the charge injection from the LUMO is quenched since this state lies
within the substrate band gap. We compute the resonant charge-transfer times
from LUMO+1 and LUMO+2, and systematically investigate the dependence of the
elastic lifetimes of these states on the alignment among adsorbate and
substrate states.Comment: 24 pages, 6 figures, to appear in Journal of Physical Chemistry
Absence of cardiotrophin 1 is associated with decreased age-dependent arterial stiffness and increased longevity in mice
Cardiotrophin 1 (CT-1), an interleukin 6 family member, promotes fibrosis and arterial stiffness. We hypothesized
that the absence of CT-1 influences arterial fibrosis and stiffness, senescence, and life span. In senescent 29-month-
old mice, vascular function was analyzed by echotracking device. Arterial histomorphology, senescence, metabolic,
inflammatory, and oxidative stress parameters were measured by immunohistochemistry, reverse transcription polymerase
chain reaction, Western blot, and ELISA. Survival rate of wild-type and CT-1–null mice was studied. Vascular smooth
muscle cells were treated with CT-1 (10
−9
mol/L) for 15 days to analyze senescence. The wall stress-incremental elastic
modulus curve of old CT-1–null mice was shifted rightward as compared with wild-type mice, indicating decreased
arterial stiffness. Media thickness and wall fibrosis were lower in CT-1–null mice. CT-1–null mice showed decreased
levels of inflammatory, apoptotic, and senescence pathways, whereas telomere-linked proteins, DNA repair proteins,
and antioxidant enzyme activities were increased. CT-1–null mice displayed a 5-month increased median longevity
compared with wild-type mice. In vascular smooth muscle cells, chronic CT-1 stimulation upregulated apoptotic and
senescence markers and downregulated telomere-linked proteins. The absence of CT-1 is associated with decreased
arterial fibrosis, stiffness, and senescence and increased longevity in mice likely through downregulating apoptotic,
senescence, and inflammatory pathways. CT-1 may be a major regulator of arterial stiffness with a major impact on the
aging proces
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
Contribution to the understanding of tribological properties of graphite intercalation compounds with metal chloride
Intrinsic tribological properties of lamellar compounds are usually attributed to the presence of van der Waals gaps in their structure through which interlayer interactions are weak. The controlled variation of the distances and interactions between graphene layers by intercalation of electrophilic species in graphite is used in order to explore more deeply the friction reduction properties of low-dimensional compounds. Three graphite intercalation compounds with antimony pentachloride, iron trichloride and aluminium trichloride are studied. Their tribological properties are correlated to their structural parameters, and the interlayer interactions are deduced from ab initio bands structure calculations
Status of the SOLEIL femtosecond X-ray source
http://accelconf.web.cern.ch/AccelConf/FEL2012/papers/wepd04.pdfInternational audienceAn electron bunch slicing setup is presently under construction on the SOLEIL storage ring for delivering 100 fs (rms) long photon pulses to two undulator-based beamlines providing soft (TEMPO) and hard X-rays (CRISTAL). Thanks to the non-zero dispersion function present in all straight sections of the storage ring, the sliced bunches can be easily separated from the core bunches. The modulator is a wiggler composed of 20 periods of 164.4 mm. It produces a magnetic field of 1.8 T at a minimum gap of 14.5 mm. To modulate the kinetic energy of the electrons in the wiggler, a Ti:Sa laser will be used, which produces 50 fs pulses at 800 nm with a repetition rate of 2.5 kHz. The laser beam is splitted into two branches in order to provide 2 mJ to the modulator and 0.5 mJ as pump pulse for the CRISTAL and TEMPO end stations. Focusing optics and beam path, from the laser hutch to the inside of the storage ring tunnel are presently under finalization. In this paper, we will report on the specificities of the SOLEIL setup, the status of its installation and the expected performances
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