3,114 research outputs found
Upregulation and function of GADD45γ in unilateral ureteral obstruction
We performed differential display analysis to determine transcriptional activity in the rat kidney, following unilateral ureteral obstruction and found a 12-fold increase in the expression of Growth Arrest and DNA Damage-45γ (GADD45γ), a stress-responsive molecule that interacts with cell-cycle proteins. GADD45γ was strongly expressed in as little as 6 h following ureteric obstruction in the renal tubules, and was also found in kidney tissue of patients with chronic glomerulonephritis. Adenovirus-mediated expression of GADD45γ in cultured renal tubular cells activated p38 along with a significant upregulation of C–C and C–X3–C chemokine ligands and fibrosis-related factors such as several matrix metalloproteinases, transforming growth factor-β1, decorin, and bone morphogenetic protein 2. Silencing of GADD45γ expression significantly blunted the upregulation of these inflammatory and fibrogenic mediators and monocyte infiltration in the ureteral obstructed rat kidney. Our study shows that GADD45γ is quickly upregulated in the kidney with an obstructed ureter, enhancing the production of factors regulating the pathogenesis of kidney disease
Exclusive Measurement of the Nonmesonic Weak Decay of ^{5}_{\Lambda}He Hypernucleus
We performed a coincidence measurement of two nucleons emitted from the
nonmesonic weak decay (NMWD) of ^{5}_{\Lambda}He formed via the
^{6}Li(\pi^+,K^+) reaction. The energies of two nucleons and the pair number
distributions in the opening angle between them were measured. In both np and
nn pairs, we observed a clean back-to-back correlation coming from the two-body
decay of \Lambda p --> n p and \Lambda n --> n n, respectively. The ratio of
the nucleon pair numbers was N_{nn}/N_{np}=0.45 \pm 0.11(stat)\pm 0.03(syst) in
the kinematic region of cos(theta_{NN}) < -0.8. Since each decay mode was
exclusively detected, the measured ratio should be close to the ratio of
\Gamma(\Lambda p --> np)/\Gamma(\Lambda n --> nn).
The ratio is consistent with recent theoretical calculations based on the
heavy meson/direct quark exchange picture.Comment: Submitted to Phys. Rev. lett., 4 pages, 3 figure
Impact of low-pressure systems on winter heavy air pollution in the northwest Sichuan Basin, China
The cities of Chengdu, Deyang, and
Mianyang in the northwest Sichuan Basin are part of a rapidly developing
urban agglomeration adjoining the eastern slopes of the Tibetan Plateau.
Heavy air pollution events have frequently occurred over these cities in recent
decades, but the effects of meteorological conditions on these pollution
events are unclear. We explored the effects of weather systems on winter
heavy air pollution from 1 January 2006 to 31 December 2012 and from
1 January 2014 to 28 February 2017. A total of 10 heavy air pollution events occurred
during the research period and 8 of these took place while the region was
affected by a dry low-pressure system at 700 hPa. When the urban
agglomeration was in front of the low-pressure system and the weather
conditions were controlled by a warm southerly air flow, a strong
temperature inversion appeared above the atmospheric boundary layer acting as
a lid. Forced by this strong inversion layer, the local secondary circulation
was confined to the atmospheric boundary layer, and the horizontal wind
speed in the lower troposphere was low. As a result, vertical mixing and
horizontal dispersion in the atmosphere were poor, favoring the formation of
heavy air pollution events. After the low-pressure system had transited over
the region, the weather conditions in the urban agglomeration were controlled
by a dry and cold air flow from the northwest at 700 hPa. The strong
inversion layer gradually dissipated, the secondary circulation enhanced and
uplifted, and the horizontal wind speed in the lower troposphere also
increased, resulting in a sharp decrease in the concentration of air
pollutants. The strong inversion layer above the atmospheric boundary layer
induced by the low-pressure system at 700 hPa thus played a key role in the
formation of heavy air pollution during the winter months in this urban
agglomeration. This study provides scientific insights for forecasting heavy
air pollution in this region of China.</p
Structure of a model TiO2 photocatalytic interface
The interaction of water with TiO2 is crucial to many of its practical
applications, including photocatalytic water splitting. Following the first
demonstration of this phenomenon 40 years ago there have been numerous studies
of the rutile single-crystal TiO2(110) interface with water. This has provided
an atomic-level understanding of the water-TiO2 interaction. However, nearly
all of the previous studies of water/TiO2 interfaces involve water in the
vapour phase. Here, we explore the interfacial structure between liquid water
and a rutile TiO2(110) surface pre-characterized at the atomic level. Scanning
tunnelling microscopy and surface X-ray diffraction are used to determine the
structure, which is comprised of an ordered array of hydroxyl molecules with
molecular water in the second layer. Static and dynamic density functional
theory calculations suggest that a possible mechanism for formation of the
hydroxyl overlayer involves the mixed adsorption of O2 and H2O on a partially
defected surface. The quantitative structural properties derived here provide a
basis with which to explore the atomistic properties and hence mechanisms
involved in TiO2 photocatalysis
Constitutive modeling of deformation behavior of high-entropy alloys with face-centered cubic crystal structure
A constitutive model based on the dislocation glide and deformation twinning is adapted to face-centered cubic high-entropy alloys (HEAs) as exemplified by the CrMnFeCoNi system. In this model, the total dislocation density is considered as the only internal variable, while the evolution equation describing its variation during plastic deformation is governed by the volume fraction of twinned material. The suitability of the model for describing the strain hardening behavior of HEAs was verified experimentally through compression tests on alloy CrMnFeCoNi and its microstructure characterization by electron backscatter diffraction and X-ray diffraction using synchrotron radiation. ? 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.1111Ysciescopu
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