689 research outputs found
Light Higgsino from Axion Dark Radiation
The recent observations imply that there is an extra relativistic degree of
freedom coined dark radiation. We argue that the QCD axion is a plausible
candidate for the dark radiation, not only because of its extremely small mass,
but also because in the supersymmetric extension of the Peccei-Quinn mechanism
the saxion tends to dominate the Universe and decays into axions with a sizable
branching fraction. We show that the Higgsino mixing parameter mu is bounded
from above when the axions produced at the saxion decays constitute the dark
radiation: mu \lesssim 300 GeV for a saxion lighter than 2m_W, and mu less than
the saxion mass otherwise. Interestingly, the Higgsino can be light enough to
be within the reach of LHC and/or ILC even when the other superparticles are
heavy with mass about 1 TeV or higher. We also estimate the abundance of axino
produced by the decays of Higgsino and saxion.Comment: 18 pages, 1 figure; published in JHE
Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections.
Background:
A number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.<p></p>
Methods:
Minimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.<p></p>
Results:
CHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.<p></p>
Conclusions:
Overall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.<p></p>
Landscape of multi-nucleotide variants in 125,748 human exomes and 15,708 genomes.
Multi-nucleotide variants (MNVs), defined as two or more nearby variants existing on the same haplotype in an individual, are a clinically and biologically important class of genetic variation. However, existing tools typically do not accurately classify MNVs, and understanding of their mutational origins remains limited. Here, we systematically survey MNVs in 125,748 whole exomes and 15,708 whole genomes from the Genome Aggregation Database (gnomAD). We identify 1,792,248 MNVs across the genome with constituent variants falling within 2 bp distance of one another, including 18,756 variants with a novel combined effect on protein sequence. Finally, we estimate the relative impact of known mutational mechanisms - CpG deamination, replication error by polymerase zeta, and polymerase slippage at repeat junctions - on the generation of MNVs. Our results demonstrate the value of haplotype-aware variant annotation, and refine our understanding of genome-wide mutational mechanisms of MNVs
Low dose radiation and cancer in A-bomb survivors: latency and non-linear dose-response in the 1950–90 mortality cohort
BACKGROUND: Analyses of Japanese A-bomb survivors' cancer mortality risks are used to establish recommended annual dose limits, currently set at 1 mSv (public) and 20 mSv (occupational). Do radiation doses below 20 mSv have significant impact on cancer mortality in Japanese A-bomb survivors, and is the dose-response linear? METHODS: I analyse stomach, liver, lung, colon, uterus, and all-solid cancer mortality in the 0 – 20 mSv colon dose subcohort of the 1950–90 (grouped) mortality cohort, by Poisson regression using a time-lagged colon dose to detect latency, while controlling for gender, attained age, and age-at-exposure. I compare linear and non-linear models, including one adapted from the cellular bystander effect for α particles. RESULTS: With a lagged linear model, Excess Relative Risk (ERR) for the liver and all-solid cancers is significantly positive and several orders of magnitude above extrapolations from the Life Span Study Report 12 analysis of the full cohort. Non-linear models are strongly superior to the linear model for the stomach (latency 11.89 years), liver (36.90), lung (13.60) and all-solid (43.86) in fitting the 0 – 20 mSv data and show significant positive ERR at 0.25 mSv and 10 mSv lagged dose. The slope of the dose-response near zero is several orders of magnitude above the slope at high doses. CONCLUSION: The standard linear model applied to the full 1950–90 cohort greatly underestimates the risks at low doses, which are significant when the 0 – 20 mSv subcohort is modelled with latency. Non-linear models give a much better fit and are compatible with a bystander effect
Effects of vessel traffic on relative abundance and behaviour of cetaceans : the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea
Acknowledgements This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco (CTS) and by the National Park of the Archipelago de La Maddalena. We thank the Natural Reserve of Bocche di Bonifacio for the support provided during data collection. The authors thank the numerous volunteers of the Caprera Dolphin Research Centre and especially Marco Ferraro, Mirko Ugo, Angela Pira and Maurizio Piras whose assistance during field observation and skills as a boat driver were invaluable.Peer reviewedPostprin
AAV5-Factor VIII Gene Transfer in Severe Hemophilia A.
BACKGROUND: Patients with hemophilia A rely on exogenous factor VIII to prevent bleeding in joints, soft tissue, and the central nervous system. Although successful gene transfer has been reported in patients with hemophilia B, the large size of the factor VIII coding region has precluded improved outcomes with gene therapy in patients with hemophilia A. METHODS: We infused a single intravenous dose of a codon-optimized adeno-associated virus serotype 5 (AAV5) vector encoding a B-domain-deleted human factor VIII (AAV5-hFVIII-SQ) in nine men with severe hemophilia A. Participants were enrolled sequentially into one of three dose cohorts (low dose [one participant], intermediate dose [one participant], and high dose [seven participants]) and were followed through 52 weeks. RESULTS: Factor VIII activity levels remained at 3 IU or less per deciliter in the recipients of the low or intermediate dose. In the high-dose cohort, the factor VIII activity level was more than 5 IU per deciliter between weeks 2 and 9 after gene transfer in all seven participants, and the level in six participants increased to a normal value (>50 IU per deciliter) that was maintained at 1 year after receipt of the dose. In the high-dose cohort, the median annualized bleeding rate among participants who had previously received prophylactic therapy decreased from 16 events before the study to 1 event after gene transfer, and factor VIII use for participant-reported bleeding ceased in all the participants in this cohort by week 22. The primary adverse event was an elevation in the serum alanine aminotransferase level to 1.5 times the upper limit of the normal range or less. Progression of preexisting chronic arthropathy in one participant was the only serious adverse event. No neutralizing antibodies to factor VIII were detected. CONCLUSIONS: The infusion of AAV5-hFVIII-SQ was associated with the sustained normalization of factor VIII activity level over a period of 1 year in six of seven participants who received a high dose, with stabilization of hemostasis and a profound reduction in factor VIII use in all seven participants. In this small study, no safety events were noted, but no safety conclusions can be drawn. (Funded by BioMarin Pharmaceutical; ClinicalTrials.gov number, NCT02576795 ; EudraCT number, 2014-003880-38 .).BioMarin Pharmaceutical
Phenomenological Implications of Deflected Mirage Mediation: Comparison with Mirage Mediation
We compare the collider phenomenology of mirage mediation and deflected
mirage mediation, which are two recently proposed "mixed" supersymmetry
breaking scenarios motivated from string compactifications. The scenarios
differ in that deflected mirage mediation includes contributions from gauge
mediation in addition to the contributions from gravity mediation and anomaly
mediation also present in mirage mediation. The threshold effects from gauge
mediation can drastically alter the low energy spectrum from that of pure
mirage mediation models, resulting in some cases in a squeezed gaugino spectrum
and a gluino that is much lighter than other colored superpartners. We provide
several benchmark deflected mirage mediation models and construct model lines
as a function of the gauge mediation contributions, and discuss their discovery
potential at the LHC.Comment: 29 pages, 9 figure
Robust penetrating microelectrodes for neural interfaces realized by titanium micromachining
Neural prosthetic interfaces based upon penetrating microelectrode devices have broadened our understanding of the brain and have shown promise for restoring neurological functions lost to disease, stroke, or injury. However, the eventual viability of such devices for use in the treatment of neurological dysfunction may be ultimately constrained by the intrinsic brittleness of silicon, the material most commonly used for manufacture of penetrating microelectrodes. This brittleness creates predisposition for catastrophic fracture, which may adversely affect the reliability and safety of such devices, due to potential for fragmentation within the brain. Herein, we report the development of titanium-based penetrating microelectrodes that seek to address this potential future limitation. Titanium provides advantage relative to silicon due to its superior fracture toughness, which affords potential for creation of robust devices that are resistant to catastrophic failure. Realization of these devices is enabled by recently developed techniques which provide opportunity for fabrication of high-aspect-ratio micromechanical structures in bulk titanium substrates. Details are presented regarding the design, fabrication, mechanical testing, in vitro functional characterization, and preliminary in vivo testing of devices intended for acute recording in rat auditory cortex and thalamus, both independently and simultaneously
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