868 research outputs found
Proinflammatory cytokines inhibit osteogenic differentiation from stem cells: implications for bone repair during inflammation
SummaryObjectiveThe effects of inflammation on bone development from mesenchymal stem cells (MSC) are unclear due to the difficulty in isolating MSC. The aim of this study was to develop a MSC isolation method and to determine the in vitro effects of interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) on their osteogenic differentiation.MethodsMurine MSC were isolated from the limbs of C57/Bl6 mice through collagenase digestion of bone and enriched as the Stem cell antigen (Sca-1)+ CD31− CD45− population, using lineage immunodepletion, followed by fluorescence-activated cell sorting (FACS). They were differentiated along the osteoblast linage in the presence or absence of IL-1β and TNFα. Mineralization was measured as was the expression of a number of osteogenic genes by quantitative polymerase chain reaction (PCR).ResultsWe show that osteogenic differentiation from the MSC population is suppressed by IL-1β and TNFα. In addition to suppression of bone mineralization, both cytokines inhibited the differentiation-associated increases in alkaline phosphatase (ALP) activity and the gene expression for ALP, α1(I) procollagen, runt-related transcription factor 2 (Runx2) and osterix. However, only TNFα inhibited osteonectin and osteopontin mRNA expression and only IL-1β reduced cell proliferation.ConclusionsThe convenient isolation technique enables the easy generation of sufficient MSC to permit the molecular analysis of their differentiation. We were thus able to show that the proinflammatory cytokines, IL-1β and TNFα, can compromise bone development from this primary MSC population, although with some significant differences. The potential involvement of specific inflammatory mediators needs to be taken into account if optimal bone repair and presumably that of other tissues are to be achieved with MSC
Loin pain hematuria syndrome
Digitalitzat per Artypla
Scaling in Numerical Simulations of Domain Walls
We study the evolution of domain wall networks appearing after phase
transitions in the early Universe. They exhibit interesting dynamical scaling
behaviour which is not yet well understood, and are also simple models for the
more phenomenologically acceptable string networks. We have run numerical
simulations in two- and three-dimensional lattices of sizes up to 4096^3. The
theoretically predicted scaling solution for the wall area density A ~ 1/t is
supported by the simulation results, while no evidence of a logarithmic
correction reported in previous studies could be found. The energy loss
mechanism appears to be direct radiation, rather than the formation and
collapse of closed loops or spheres. We discuss the implications for the
evolution of string networks.Comment: 7pp RevTeX, 9 eps files (including six 220kB ones
Radiocarbon dates from jar and coffin burials of the Cardamom Mountains reveal a unique mortuary ritual in Cambodia's late- to post-Angkor period (15th-17th centuries AD)
We present the first radiocarbon dates from previously unrecorded, secondary burials in the Cardamom Mountains, Cambodia. The mortuary ritual incorporates nautical tradeware ceramic jars and log coffins fashioned from locally harvested trees as burial containers, which were set out on exposed rock ledges at 10 sites in the eastern Cardamom Massif. The suite of 28 14C ages from 4 of these sites (Khnorng Sroal, Phnom Pel, Damnak Samdech, and Khnang Tathan) provides the first estimation of the overall time depth of the practice. The most reliable calendar date ranges from the 4 sites reveals a high- land burial ritual unrelated to lowland Khmer culture that was practiced from cal AD 1395 to 1650. The time period is concurrent with the 15th century decline of Angkor as the capital of the Khmer kingdom and its demise about AD 1432, and the subsequent shift of power to new Mekong trade ports such as Phnom Penh, Udong, and Lovek. We discuss the Cardamom ritual relative to known funerary rituals of the pre to post-Angkorian periods, and to similar exposed jar and coffin burial rituals in Mainland and Island Southeast Asia
Electric current circuits in astrophysics
Cosmic magnetic structures have in common that they are anchored
in a dynamo, that an external driver converts kinetic energy into internal
magnetic energy, that this magnetic energy is transported as Poynting fl ux across the magnetically dominated structure, and that the magnetic energy
is released in the form of particle acceleration, heating, bulk motion,
MHD waves, and radiation. The investigation of the electric current system is
particularly illuminating as to the course of events and the physics involved.
We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial
magnetic storms
Quantum walks: a comprehensive review
Quantum walks, the quantum mechanical counterpart of classical random walks,
is an advanced tool for building quantum algorithms that has been recently
shown to constitute a universal model of quantum computation. Quantum walks is
now a solid field of research of quantum computation full of exciting open
problems for physicists, computer scientists, mathematicians and engineers.
In this paper we review theoretical advances on the foundations of both
discrete- and continuous-time quantum walks, together with the role that
randomness plays in quantum walks, the connections between the mathematical
models of coined discrete quantum walks and continuous quantum walks, the
quantumness of quantum walks, a summary of papers published on discrete quantum
walks and entanglement as well as a succinct review of experimental proposals
and realizations of discrete-time quantum walks. Furthermore, we have reviewed
several algorithms based on both discrete- and continuous-time quantum walks as
well as a most important result: the computational universality of both
continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing
Journa
HIV-1 diversity among young women in rural South Africa: HPTN 068
Background South Africa has one of the highest rates of HIV-1 (HIV) infection world-wide, with the highest rates among young women. We analyzed the molecular epidemiology and evolutionary history of HIV in young women attending high school in rural South Africa. Methods Samples were obtained from the HPTN 068 randomized controlled trial, which evaluated the effect of cash transfers for school attendance on HIV incidence in women aged 13–20 years (Mpumalanga province, 2011–2015). Plasma samples from HIV-infected participants were analyzed using the ViroSeq HIV-1 Genotyping assay. Phylogenetic analysis was performed using 200 pol gene study sequences and 2,294 subtype C reference sequences from South Africa. Transmission clusters were identified using Cluster Picker and HIV-TRACE, and were characterized using demographic and other epidemiological data. Phylodynamic analyses were performed using the BEAST software. Results The study enrolled 2,533 young women who were followed through their expected high school graduation date (main study); some participants had a post-study assessment (follow-up study). Two-hundred-twelve of 2,533 enrolled young women had HIV infection. HIV pol sequences were obtained for 94% (n = 201/212) of the HIV-infected participants. All but one of the sequences were HIV-1 subtype C; the non-C subtype sequence was excluded from further analysis. Median pairwise genetic distance between the subtype C sequences was 6.4% (IQR: 5.6–7.2). Overall, 26% of study sequences fell into 21 phylogenetic clusters with 2–6 women per cluster. Thirteen (62%) clusters included women who were HIV-infected at enrollment. Clustering was not associated with study arm, demographic or other epidemiological factors. The estimated date of origin of HIV subtype C in the study population was 1958 (95% highest posterior density [HPD]: 1931–1980), and the median estimated substitution rate among study pol sequences was 1.98x10-3 (95% HPD: 1.15x10-3–2.81x10-3) per site per year. Conclusions Phylogenetic analysis suggests that multiple HIV subtype C sublineages circulate among school age girls in South Africa. There were no substantive differences in the molecular epidemiology of HIV between control and intervention arms in the HPTN 068 trial
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
Analysis of LIGO data for gravitational waves from binary neutron stars
We report on a search for gravitational waves from coalescing compact binary
systems in the Milky Way and the Magellanic Clouds. The analysis uses data
taken by two of the three LIGO interferometers during the first LIGO science
run and illustrates a method of setting upper limits on inspiral event rates
using interferometer data. The analysis pipeline is described with particular
attention to data selection and coincidence between the two interferometers. We
establish an observational upper limit of 1.7 \times 10^{2}M_\odot$.Comment: 17 pages, 9 figure
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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