An immunoassay is an analytical test method in which analyte quantitation is based on signal responses generated as a consequence of an antibody–antigen interaction. They are the method of choice for ...the measurement of a large panel of diagnostic markers. Not only are they fully automated, allowing for a short turnaround time and high throughput, but offer high sensitivity and specificity with low limits of detection for a wide range of analytes. Many immunoassay manufacturers exploit the extremely high affinity of biotin for streptavidin in their assay design architectures as a means to immobilize and detect analytes of interest. The biotin–(strept)avidin system is, however, vulnerable to interference with high levels of supplemental biotin that may cause elevated or suppressed test results. Since this system is heavily applied in clinical diagnostics, biotin interference has become a serious concern, prompting the FDA to issue a safety report alerting healthcare workers and the public about the potential harm of ingesting high levels of supplemental biotin contributing toward erroneous diagnostic test results. This review includes a general background and historical prospective of immunoassays with a focus on the biotin–streptavidin system, interferences within the system, and what mitigations are applied to minimize false diagnostic results.
The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in Namibia. It measures cosmic gamma rays of very high ...energies (VHE; >100GeV) using the Earth’s atmosphere as a calorimeter. The H.E.S.S. Array entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. This paper will give an overview of the current H.E.S.S. central data acquisition (DAQ) system with particular emphasis on the upgrades made to integrate the fifth telescope into the array. At first, the various requirements for the central DAQ are discussed then the general design principles employed to fulfil these requirements are described. Finally, the performance, stability and reliability of the H.E.S.S. central DAQ are presented. One of the major accomplishments is that less than 0.8% of observation time has been lost due to central DAQ problems since 2009.
The High Energy Stereoscopic System (H.E.S.S.) is an array of five imaging atmospheric Cherenkov telescopes located in the Khomas Highland in Namibia. Very high energy gamma rays are detected using ...the Imaging Atmospheric Cherenkov Technique. Using the fifth, larger telescope of the array with a huge mirror area of 600 m2, it was possible to lower the energy threshold down to ≈ 30 GeV. With this unique ability to observe large amounts of gamma rays in the high energy gamma-ray regime (< 100 GeV) by using the large effective area of the fifth telescope at these energies, the H.E.S.S. experiment is ideally suited to observe short time scale transient events like gamma-ray bursts (GRBs). Originally detected by the Vela satellites in 1967, GRBs are among the most energetic processes in the known Universe. Extrapolating the spectrum of long duration GRBs (i.e. a GRB duration of the order of a few seconds or above) measured by current satellite experiments like Fermi, which measured gamma rays up to 95 GeV for GRB 130427A, a detection of these phenomena with the H.E.S.S. array is possible. This paper will give an update on the H.E.S.S. Target of Opportunity (ToO) alert system. It is used for an immediate and fully automatic response to a prompt GRB alert received via the Gamma-Ray Coordinates Network (GCN). The key feature of this system is a fast repointing of the whole array to a new observation position. We will discuss the implementation of the ToO alert system as well as its overall performance. Moreover, we will show that software improvements alone reduced the average response time to a ToO alert to below 60s on average, a decrease by more than 50%.
Prebiotics in obesity Carnahan, S; Balzer, A; Panchal, S K ...
Panminerva medica
56, Številka:
2
Journal Article
Recenzirano
Obesity was probably rare in ancient times, with the current increase starting in the Industrial Revolution of the eighteenth century, and becoming much more widespread from about 1950, so concurrent ...with the increased consumption of carbohydrates from cereals in the Green Revolution. However, dietary components such as oligosaccharides from plants including cereals may improve health following fermentation to short-chain carboxylic acids in the intestine by bacteria which constitute of the microbiome. Such non-digestible and fermentable components of diet, called prebiotics, have been part of the human diet since at least Palaeolithic times, and include components of the cereals domesticated in the Neolithic Revolution. If consumption of these cereals has now increased, why is obesity increasing? One reason could be lowered prebiotic intake combined with increased intake of simple sugars, thus changing the bacteria in the microbiome. Processing of food has played an important role in this change of diet composition. Since obesity is a low-grade inflammation, changing the microbiome by increased consumption of simple carbohydrates and saturated fats may lead to obesity via increased systemic inflammation. Conversely, there is now reasonable evidence that increased dietary prebiotic intake decreases inflammation, improves glucose metabolism and decreases obesity. Would widespread increases in prebiotics in the modern diet, so mimicking Palaeolithic or Neolithic nutrition, decrease the incidence and morbidity of obesity in our communities?
Very high energy (VHE; E > or =, slanted E 100 GeV) and high-energy (HE; 100 MeV < or =, slanted E < or =, slanted 100 GeV) data from gamma-ray observations performed with the H.E.S.S. telescope ...array and the Fermi-LAT instrument, respectively, are analyzed in order to investigate the non-thermal processes in the starburst galaxy NGC 253. A power-law fit to the differential HE gamma-ray spectrum reveals a photon index of Gamma = 2.24 + or - 0.14 sub(stat) + or - 0.03 sub(sys) and an integral flux between 200 MeV and 200 GeV of F(0.2-200 GeV) = (4.9 + or - 1.0 sub(stat) + or - 0.3 sub(sys)) x 10 super(-9) cm super(-2) s super(-1). No evidence for a spectral break or turnover is found over the dynamic range of both the LAT instrument and the H.E.S.S. experiment: a combined fit of a power law to the HE and VHE gamma-ray data results in a differential photon index Gamma = 2.34 + or - 0.03 with a p-value of 30%..
Observations of astrophysical transients have brought many novel discoveries and provided new insights into the physical processes at work under extreme conditions in the Universe. Multi-wavelength ...and multi-messenger observations of variable objects require dedicated procedures and follow-up systems capable of digesting and reacting to external alerts to execute coordinated follow-up campaigns. The main functions of such follow-up systems are the processing, filtering, and ranking of the incoming alerts, the fully automated rapid execution of the observations according to an observation strategy tailored to the instrument, and real-time data analysis with feedback to the operators and other instruments. The High Energy Stereoscopic System (H.E.S.S.) has been searching for transient phenomena since its inauguration in 2003. In this paper, we describe the transients follow-up system of H.E.S.S. which became operational in 2016. The system allows H.E.S.S. to conduct a more versatile, optimised, and largely autonomous transient follow-up programme, combining all major functionalities in one systematic approach. We describe the design, central functionalities, and interfaces of the follow-up system in general and its three main components in detail: the Target of Opportunity (ToO) alert system, the data acquisition and central control system, and the real-time analysis. We highlight architectural decisions and features that enable fully automatic ToO follow-up and indicate key performance metrics of the subsystems. We discuss the system's capabilities and highlight the need for a fine-tuned interplay of the different subsystems in order to react quickly and reliably. Lessons learnt from the development, integration, and operation of the follow-up system are reviewed in light of new and large science infrastructures and associated challenges in this exciting new era of inter-operable astronomy.
The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the ...measurement of the imprint of the EBL opacity to γ-rays on the spectra of the brightest extragalactic sources detected with the High Energy Stereoscopic System (H.E.S.S.). The originality of the method lies in the joint fit of the EBL optical depth and of the intrinsic spectra of the sources, assuming intrinsic smoothness. Analysis of a total of ~105γ-ray events enables the detection of an EBL signature at the 8.8σ level and constitutes the first measurement of the EBL optical depth using very-high energy (E > 100 GeV) γ-rays. The EBL flux density is constrained over almost two decades of wavelengths 0.30 μm, 17 μm and the peak value at 1.4 μm is derived as λFλ = 15 ± 2stat ± 3sys nW m-2 sr-1.
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3-6) x 10(9) M-circle dot) provides a unique opportunity to investigate the origin of very high ...energy (VHE; E > 100 GeV) gamma-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE gamma-ray emitter since 2006. The VHE gamma-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE gamma-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of tau(rise)(d) = (1.69 +/- 0.30) days and tau(decay)(d) = (0.611 +/- 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (similar to day), peak fluxes (Phi(>0.35 TeV) similar or equal to (1-3) x 10(-11) photons cm(-2) s(-1)), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken similar to 3 days after the peak of the VHE gamma-ray emission reveal an enhanced flux from the core (flux increased by factor similar to 2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M 87, spanning from radio to VHE and including data from Hubble Space Telescope, Liverpool Telescope, Very Large Array, and European VLBI Network, is used to further investigate the origin of the VHE gamma-ray emission. No unique, common MWL signature of the three VHE flares has been identified. In the outer kiloparsec jet region, in particular in HST-1, no enhanced MWL activity was detected in 2008 and 2010, disfavoring it as the origin of the VHE flares during these years. Shortly after two of the three flares (2008 and 2010), the X-ray core was observed to be at a higher flux level than its characteristic range (determined from more than 60 monitoring observations: 2002-2009). In 2005, the strong flux dominance of HST-1 could have suppressed the detection of such a feature. Published models for VHE gamma-ray emission from M 87 are reviewed in the light of the new data.
In this study, the angiogenetic effect of sintered 45S5 Bioglass® was quantitatively assessed for the first time in the arteriovenous loop (AVL) model. An AVL was created by interposition of a venous ...graft from the contralateral side between the femoral artery and vein in the medial thigh of eight rats. The loop was placed in a Teflon isolation chamber and was embedded in a sintered 45S5 Bioglass® granula matrix filled with fibrin gel. Specimens were investigated 3 weeks postoperatively by means of microcomputed tomography, histological, and morphometrical techniques. All animals tolerated the operations well. At 3 weeks, both microcomputed tomography and histology demonstrated a dense network of newly formed vessels originating from the AVL. All constructs were filled with cell-rich, highly vascularized connective tissue around the vascular axis. Analysis of vessel diameter revealed constant small vessel diameters, indicating immature new vessel sprouts. This study shows for the first time axial vascularization of a sintered 45S5 Bioglass® granula matrix. After 3 weeks, the newly generated vascular network already interfused most parts of the scaffolds and showed signs of immaturity. The intrinsic type of vascularization allows transplantation of the entire construct using the AVL pedicle.
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