756 research outputs found
Freeze-In Production of FIMP Dark Matter
We propose an alternate, calculable mechanism of dark matter genesis,
"thermal freeze-in," involving a Feebly Interacting Massive Particle (FIMP)
interacting so feebly with the thermal bath that it never attains thermal
equilibrium. As with the conventional "thermal freeze-out" production
mechanism, the relic abundance reflects a combination of initial thermal
distributions together with particle masses and couplings that can be measured
in the laboratory or astrophysically. The freeze-in yield is IR dominated by
low temperatures near the FIMP mass and is independent of unknown UV physics,
such as the reheat temperature after inflation. Moduli and modulinos of string
theory compactifications that receive mass from weak-scale supersymmetry
breaking provide implementations of the freeze-in mechanism, as do models that
employ Dirac neutrino masses or GUT-scale-suppressed interactions. Experimental
signals of freeze-in and FIMPs can be spectacular, including the production of
new metastable coloured or charged particles at the LHC as well as the
alteration of big bang nucleosynthesis.Comment: 30 pages, 7 figures, PDFLaTex. References adde
A Hypertension Risk Score for Middle-Aged and Older Adults
Determining which demographic and medical variables predict the development of hypertension could help clinicians stratify risk in both prehypertensive and nonhypertensive persons. Subject-level data from 2 community-based biracial cohorts were combined to ascertain the relationship between baseline characteristics and incident hypertension. Hypertension, defined as diastolic blood pressure â„90 mm Hg, systolic blood pressure â„140 mm Hg, or reported use of medication known to treat hypertension, was assessed prospectively at 3, 6, and 9 years. Internal validation was performed by the split-sample method with a 2:1 ratio for training and testing samples, respectively. A scoring algorithm was developed by converting the multivariable regression coefficients to integer values. Age, level of systolic or diastolic blood pressure, smoking, family history of hypertension, diabetes mellitus, high body mass index, female sex, and lack of exercise were associated with the development of hypertension in the training sample. Regression models showed moderate to high capabilities of discrimination between hypertension vs nonhypertension (area under the receiver operating characteristic curve 0.75â0.78) in the testing sample at 3, 6, and 9 years of follow-up. This risk calculator may aide health care providers in guiding discussions with patients about the risk for progression to hypertension
Abelian gauge potentials on cubic lattices
The study of the properties of quantum particles in a periodic potential
subject to a magnetic field is an active area of research both in physics and
mathematics; it has been and it is still deeply investigated. In this review we
discuss how to implement and describe tunable Abelian magnetic fields in a
system of ultracold atoms in optical lattices. After discussing two of the main
experimental schemes for the physical realization of synthetic gauge potentials
in ultracold set-ups, we study cubic lattice tight-binding models with
commensurate flux. We finally examine applications of gauge potentials in
one-dimensional rings.Comment: To appear on: "Advances in Quantum Mechanics: Contemporary Trends and
Open Problems", G. Dell'Antonio and A. Michelangeli eds., Springer-INdAM
series 201
Crystalline Gaq3Nanostructures: Preparation, Thermal Property and Spectroscopy Characterization
Crystalline Gaq31-D nanostructures and nanospheres could be fabricated by thermal evaporation under cold trap. The influences of the key process parameters on formation of the nanostructures were also investigated. It has been demonstrated that the morphology and dimension of the nanostructures were mainly controlled by working temperature and working pressure. One-dimensional nanostructures were fabricated at a lower working temperature, whereas nanospheres were formed at a higher working temperature. Larger nanospheres could be obtained when a higher working pressure was applied. The XRD, FTIR, and NMR analyses evidenced that the nanostructures mainly consisted of ÎŽ-phase Gaq3. Their DSC trace revealed two small exothermic peaks in addition to the melting endotherm. The one in lower temperature region was ascribed to a transition from ÎŽ to ÎČ phase, while another in higher temperature region could be identified as a transition from ÎČ to ÎŽ phase. All the crystalline nanostructures show similar PL spectra due to absence of quantum confinement effect. They also exhibited a spectral blue shift because of a looser interligand spacing and reduced orbital overlap in their ÎŽ-phase molecular structures
Humanization and Characterization of an Anti-Human TNF-α Murine Monoclonal Antibody
A murine monoclonal antibody, m357, showing the highly neutralizing activities for human tumor necrosis factor (TNF-α) was chosen to be humanized by a variable domain resurfacing approach. The non-conserved surface residues in the framework regions of both the heavy and light chain variable regions were identified via a molecular modeling of m357 built by computer-assisted homology modeling. By replacing these critical surface residues with the human counterparts, a humanized version, h357, was generated. The humanized h357 IgG1 was then stably expressed in a mammalian cell line and the purified antibody maintained the high antigen binding affinity as compared with the parental m357 based on a soluble TNF-α neutralization bioassay. Furthermore, h357 IgG1 possesses the ability to mediate antibody-dependent cell-mediated cytotoxicity and complement dependent cytotoxicity upon binding to cells bearing the transmembrane form of TNF-α. In a mouse model of collagen antibody-induced arthritis, h357 IgG significantly inhibited disease progression by intra-peritoneal injection of 50 ”g/mouse once-daily for 9 consecutive days. These results provided a basis for the development of h357 IgG as therapeutic use
Combination of the novel histone deacetylase inhibitor YCW1 and radiation induces autophagic cell death through the downregulation of BNIP3 in triple-negative breast cancer cells in vitro and in an orthotopic mouse model
Regulation of the Matriptase-Prostasin Cell Surface Proteolytic Cascade by Hepatocyte Growth Factor Activator Inhibitor-1 during Epidermal Differentiation
Matriptase, a membrane-tethered serine protease, plays essential roles in epidermal differentiation and barrier function, largely mediated via its activation of prostasin, a glycosylphosphatidylinositol-anchored serine protease. Matriptase activity is tightly regulated by its inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) such that free active matriptase is only briefly available to act on its substrates. In the current study we provide evidence for how matriptase activates prostasin under this tight control by HAI-1. When primary human keratinocytes are induced to differentiate in a skin organotypic culture model, both matriptase and prostasin are constitutively activated and then inhibited by HAI-1. These processes also occur in HaCaT human keratinocytes when matriptase activation is induced by exposure of the cells to a pH 6.0 buffer. Using this acid-inducible activation system we demonstrate that prostatin activation is suppressed by matriptase knockdown and by blocking matriptase activation with sodium chloride, suggesting that prostatin activation is dependent on matriptase in this system. Kinetics studies further reveal that the timing of autoactivation of matriptase, prostasin activation, and inhibition of both enzymes by HAI-1 binding are closely correlated. These data suggest that, during epidermal differentiation, the matriptase-prostasin proteolytic cascade is tightly regulated by two mechanisms: 1) prostasin activation temporally coupled to matriptase autoactivation and 2) HAI-1 rapidly inhibiting not only active matriptase but also active prostasin, resulting in an extremely brief window of opportunity for both active matriptase and active prostasin to act on their substrates
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at â s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fbâ1 of â s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Hyperspectral phasor analysis enables multiplexed 5D in vivo imaging
Time-lapse imaging of multiple labels is challenging for biological imaging as noise, photobleaching and phototoxicity compromise signal quality, while throughput can be limited by processing time. Here, we report software called Hyper-Spectral Phasors (HySP) for denoising and unmixing multiple spectrally overlapping fluorophores in a low signal-to-noise regime with fast analysis. We show that HySP enables unmixing of seven signals in time-lapse imaging of living zebrafish embryos
Elderly persons in the risk zone. Design of a multidimensional, health-promoting, randomised three-armed controlled trial for "prefrail" people of 80+ years living at home
Background The very old (80+) are often described as a "frail" group that is particularly exposed to diseases and functional disability. They are at great risk of losing the ability to manage their activities of daily living independently. A health-promoting intervention programme might prevent or delay dependence in activities of daily life and the development of functional decline. Studies have shown that those who benefit most from a health-promoting and disease-preventive programme are persons with no, or discrete, activity restrictions. The three-armed study "Elderly in the risk zone" is designed to evaluate if multi-dimensional and multi-professional educational senior meetings are more effective than preventive home visits, and if it is possible to prevent or delay deterioration if an intervention is made when the persons are not so frail. In this paper the study design, the intervention and the outcome measures as well as the baseline characteristics of the study participants are presented. Methods/Design The study is a randomised three-armed single-blind controlled trial with follow-ups 3 months, 1 and 2 years. The study group should comprise a representative sample of pre-frail 80-year old persons still living at home in two municipalities of Gothenburg. To allow for drop-outs, it was estimated that a total of about 450 persons would need to be included in the study. The participants should live in their ordinary housing and not be dependent on the municipal home help service or care. Further, they should be independent of help from another person in activities of daily living and be cognitively intact, having a score of 25 or higher as assessed with the Mini Mental State Examination (MMSE). Discussion We believe that the design of the study, the randomisation procedure, outcome measurements and the study protocol meetings should ensure the quality of the study. Furthermore, the multi-dimensionality of the intervention, the involvement of both the professionals and the senior citizens in the planning of the
intervention should have the potential to effectively target the heterogeneous needs of the
elderly. Trial registration ClinicalTrials.gov, NCT0087705
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