1,683 research outputs found
Imprint of Inhomogeneous Hydrogen Reionization on the Temperature Distribution of the Intergalactic Medium
We study the impact of inhomogeneous hydrogen reionization on the thermal
evolution of the intergalactic medium (IGM) using hydrodynamic + radiative
transfer simulations where reionization is completed either early (z ~ 9) or
late (z ~ 6). In general, we find that low-density gas near large-scale
overdensities is ionized and heated earlier than gas in the large-scale,
underdense voids. Furthermore, at a later time the IGM temperature is inversely
related to the reionization redshift because gas that is heated earlier has
more time to cool through adiabatic expansion and Compton scattering. Thus, at
the end of reionization the median temperature-density relation is an inverted
power-law with slope gamma-1 ~ -0.2, in both models. However, at fixed density,
there is up to order unity scatter in the temperature due to the distribution
of reionization redshifts. Because of the complex equation-of-state, the
evolved IGM temperature-density relations for the redshift range 4 < z < 6 can
still have significant curvature and scatter. These features must be taken into
account when interpreting the Lyman alpha absorption in high redshift quasar
spectra.Comment: 4 pages, 5 figures, accepted by ApJ Letter
Induction of microRNAs, mir-155, mir-222, mir-424 and mir-503, promotes monocytic differentiation through combinatorial regulation
Acute myeloid leukemia (AML) involves a block in terminal differentiation of
the myeloid lineage and uncontrolled proliferation of a progenitor state. Using
phorbol myristate acetate (PMA), it is possible to overcome this block in THP-1
cells (an M5-AML containing the MLL-MLLT3 fusion), resulting in differentiation
to an adherent monocytic phenotype. As part of FANTOM4, we used microarrays to
identify 23 microRNAs that are regulated by PMA. We identify four PMA-induced
micro- RNAs (mir-155, mir-222, mir-424 and mir-503) that when overexpressed
cause cell-cycle arrest and partial differentiation and when used in
combination induce additional changes not seen by any individual microRNA. We
further characterize these prodifferentiative microRNAs and show that mir-155
and mir-222 induce G2 arrest and apoptosis, respectively. We find mir-424 and
mir-503 are derived from a polycistronic precursor mir-424-503 that is under
repression by the MLL-MLLT3 leukemogenic fusion. Both of these microRNAs
directly target cell-cycle regulators and induce G1 cell-cycle arrest when
overexpressed in THP-1. We also find that the pro-differentiative mir-424 and
mir-503 downregulate the anti-differentiative mir-9 by targeting a site in its
primary transcript. Our study highlights the combinatorial effects of multiple
microRNAs within cellular systems.Comment: 45 pages 5 figure
Suizidprävention: Vorgehensweisen und Wirksamkeit
According to official statistics every year 11,000 persons in Germany die from suicide. 20 years ago nearly 19,000 suicides were registered. What are the causes for this decrease? Do suicide preventive measures contribute to the reduction of suicide rates? Different universal prevention strategies ( e. g. restriction of access to means) and selective approaches ( programs for special high-risk groups; e. g. patients after attempted suicide) are presented and discussed regarding their preventive value. In most cases it is hardly possible to scientifically prove the efficacy of suicide prevention strategies. Neither the role of psychosocial interventions nor the impact of psychotropic agents can be sufficiently quantified. Due to various methodological reasons ( e. g. small sample sizes and the lack of randomization), interpretation of the data is difficult. In terms of a comprehensive approach of suicide prevention a combination of different activities should be most adequate in the long run
Real-time non-invasive measurement and monitoring of wheel-rail contact using ultrasonic reflectometry
Rail stress levels are vital to the lifespan of rail tracks, and are responsible for the safe operation and ride comfort of train services. In particular, wheel–rail contact stress is a dominating factor affecting wear, cracking, fatigue and failure of both wheel and rail. The wheel–rail interaction problem has long been investigated, yet detailed contact information on real cases remains obscure due to the interface complexity, including the varying wheel and rail profiles and lack of effective stress characterisation methods. Ultrasound image study, as an excellent non-destructive evaluation (NDE) method, is widely used in railway systems for defect detection, stress determination and rail profile checking. Specifically, ultrasonic reflectometry has proved successful in making static machine-element contact measurements. This article introduces a novel measuring method for both short-term and long-term dynamic wheel–rail contact monitoring purposes based on ultrasonic reflectometry. The method is investigated in detail, including the study of ultrasound propagation pathways in the rail, and the optimum placement of ultrasonic elements as well as actuator–receiver combinations. The proposed monitoring technique is expected to characterise and monitor the contact behaviour of operating high-speed rail system in real-time
Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation
FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD
Ethanol reversal of tolerance to the respiratory depressant effects of morphine
Opioids are the most common drugs associated with unintentional drug overdose. Death results from respiratory depression. Prolonged use of opioids results in the development of tolerance but the degree of tolerance is thought to vary between different effects of the drugs. Many opioid addicts regularly consume alcohol (ethanol), and post-mortem analyses of opioid overdose deaths have revealed an inverse correlation between blood morphine and ethanol levels. In the present study, we determined whether ethanol reduced tolerance to the respiratory depressant effects of opioids. Mice were treated with opioids (morphine, methadone, or buprenorphine) for up to 6 days. Respiration was measured in freely moving animals breathing 5% CO(2) in air in plethysmograph chambers. Antinociception (analgesia) was measured as the latency to remove the tail from a thermal stimulus. Opioid tolerance was assessed by measuring the response to a challenge dose of morphine (10 mg/kg i.p.). Tolerance developed to the respiratory depressant effect of morphine but at a slower rate than tolerance to its antinociceptive effect. A low dose of ethanol (0.3 mg/kg) alone did not depress respiration but in prolonged morphine-treated animals respiratory depression was observed when ethanol was co-administered with the morphine challenge. Ethanol did not alter the brain levels of morphine. In contrast, in methadone- or buprenorphine-treated animals no respiratory depression was observed when ethanol was co-administered along with the morphine challenge. As heroin is converted to morphine in man, selective reversal of morphine tolerance by ethanol may be a contributory factor in heroin overdose deaths
Retinal glycoprotein enrichment by concanavalin a enabled identification of novel membrane autoantigen synaptotagmin-1 in equine recurrent uveitis.
Complete knowledge of autoantigen spectra is crucial for understanding pathomechanisms of autoimmune diseases like equine recurrent uveitis (ERU), a spontaneous model for human autoimmune uveitis. While several ERU autoantigens were identified previously, no membrane protein was found so far. As there is a great overlap between glycoproteins and membrane proteins, the aim of this study was to test whether pre-enrichment of retinal glycoproteins by ConA affinity is an effective tool to detect autoantigen candidates among membrane proteins. In 1D Western blots, the glycoprotein preparation allowed detection of IgG reactions to low abundant proteins in sera of ERU patients. Synaptotagmin-1, a Ca2+-sensing protein in synaptic vesicles, was identified as autoantigen candidate from the pre-enriched glycoprotein fraction by mass spectrometry and was validated as a highly prevalent autoantigen by enzyme-linked immunosorbent assay. Analysis of Syt1 expression in retinas of ERU cases showed a downregulation in the majority of ERU affected retinas to 24%. Results pointed to a dysregulation of retinal neurotransmitter release in ERU. Identification of synaptotagmin-1, the first cell membrane associated autoantigen in this spontaneous autoimmune disease, demonstrated that examination of tissue fractions can lead to the discovery of previously undetected novel autoantigens. Further experiments will address its role in ERU pathology
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Accuracy of epidemiological inferences based on publicly available information: retrospective comparative analysis of line lists of human cases infected with influenza A(H7N9) in China
Background: Appropriate public health responses to infectious disease threats should be based on best-available evidence, which requires timely reliable data for appropriate analysis. During the early stages of epidemics, analysis of ‘line lists’ with detailed information on laboratory-confirmed cases can provide important insights into the epidemiology of a specific disease. The objective of the present study was to investigate the extent to which reliable epidemiologic inferences could be made from publicly-available epidemiologic data of human infection with influenza A(H7N9) virus. Methods: We collated and compared six different line lists of laboratory-confirmed human cases of influenza A(H7N9) virus infection in the 2013 outbreak in China, including the official line list constructed by the Chinese Center for Disease Control and Prevention plus five other line lists by HealthMap, Virginia Tech, Bloomberg News, the University of Hong Kong and FluTrackers, based on publicly-available information. We characterized clinical severity and transmissibility of the outbreak, using line lists available at specific dates to estimate epidemiologic parameters, to replicate real-time inferences on the hospitalization fatality risk, and the impact of live poultry market closure. Results: Demographic information was mostly complete (less than 10% missing for all variables) in different line lists, but there were more missing data on dates of hospitalization, discharge and health status (more than 10% missing for each variable). The estimated onset to hospitalization distributions were similar (median ranged from 4.6 to 5.6 days) for all line lists. Hospital fatality risk was consistently around 20% in the early phase of the epidemic for all line lists and approached the final estimate of 35% afterwards for the official line list only. Most of the line lists estimated >90% reduction in incidence rates after live poultry market closures in Shanghai, Nanjing and Hangzhou. Conclusions: We demonstrated that analysis of publicly-available data on H7N9 permitted reliable assessment of transmissibility and geographical dispersion, while assessment of clinical severity was less straightforward. Our results highlight the potential value in constructing a minimum dataset with standardized format and definition, and regular updates of patient status. Such an approach could be particularly useful for diseases that spread across multiple countries
Phylogeography of Japanese encephalitis virus:genotype is associated with climate
The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate
Potential Role of miRNAs in Developmental Haemostasis
MicroRNAs (miRNAs) are an abundant class of small non-coding RNAs that are negative regulators in a crescent number of physiological and pathological processes. However, their role in haemostasis, a complex physiological process involving multitude of effectors, is just beginning to be characterized. We evaluated the changes of expression of miRNAs in livers of neonates (day one after birth) and adult mice by microarray and qRT-PCR trying to identify miRNAs that potentially may also be involved in the control of the dramatic change of hepatic haemostatic protein levels associated with this transition. Twenty one out of 41 miRNAs overexpressed in neonate mice have hepatic haemostatic mRNA as potential targets. Six of them identified by two in silico algorithms potentially bind the 3′UTR regions of F7, F9, F12, FXIIIB, PLG and SERPINC1 mRNA. Interestingly, miR-18a and miR-19b, overexpressed 5.4 and 8.2-fold respectively in neonates, have antithrombin, a key anti-coagulant with strong anti-angiogenic and anti-inflammatory roles, as a potential target. The levels of these two miRNAs inversely correlated with antithrombin mRNA levels during development (miR-19b: R = 0.81; p = 0.03; miR-18a: R = 0.91; p<0.001). These data suggest that miRNAs could be potential modulators of the haemostatic system involved in developmental haemostasis
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