770 research outputs found
Mechanical On-Chip Microwave Circulator
Nonreciprocal circuit elements form an integral part of modern measurement
and communication systems. Mathematically they require breaking of
time-reversal symmetry, typically achieved using magnetic materials and more
recently using the quantum Hall effect, parametric permittivity modulation or
Josephson nonlinearities. Here, we demonstrate an on-chip magnetic-free
circulator based on reservoir engineered optomechanical interactions.
Directional circulation is achieved with controlled phase-sensitive
interference of six distinct electro-mechanical signal conversion paths. The
presented circulator is compact, its silicon-on-insulator platform is
compatible with both superconducting qubits and silicon photonics, and its
noise performance is close to the quantum limit. With a high dynamic range, a
tunable bandwidth of up to 30 MHz and an in-situ reconfigurability as beam
splitter or wavelength converter, it could pave the way for superconducting
qubit processors with integrated and multiplexed on-chip signal processing and
readout.Comment: References have been update
Hepatic effects of Cimicifuga racemosa extract in vivo and in vitro
Abstract.: Extracts of Cimicifuga racemosa are used frequently for menopausal complaints. Cimicifuga is well tolerated but can occasionally cause liver injury. To assess hepatotoxicity of cimicifuga in more detail, ethanolic C. racemosa extract was administered orally to rats, and liver sections were analyzed by electron microscopy. Tests for cytotoxicity, mitochondrial toxicity and apoptosis/necrosis were performed using HepG2 cells. Mitochondrial toxicity was studied using isolated rat liver mitochondria. Microvesicular steatosis was found in rats treated with > 500 μg/kg body weight cimicifuga extract. In vitro, cytotoxicity was apparent at concentrations ≥ 75 μg/mL, and mitochondrial β-oxidation was impaired at concentrations ≥ 10 μg/mL. The mitochondrial membrane potential was decreased at concentrations ≥ 100 μg/mL, and oxidative phosphorylation was impaired at concentrations ≥ 300 μg/mL. The mechanism of cell death was predominantly apoptosis. C. racemosa exerts toxicity in vivo and in vitro, eventually resulting in apoptotic cell death. The results are compatible with idiosyncratic hepatotoxicity as observed in patients treated with cimicifuga extract
MetaboLab - advanced NMR data processing and analysis for metabolomics
Background\ud
Despite wide-spread use of Nuclear Magnetic Resonance (NMR) in metabolomics for the analysis of biological samples there is a lack of graphically driven, publicly available software to process large one and two-dimensional NMR data sets for statistical analysis.\ud
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Results\ud
Here we present MetaboLab, a MATLAB based software package that facilitates NMR data processing by providing automated algorithms for processing series of spectra in a reproducible fashion. A graphical user interface provides easy access to all steps of data processing via a script builder to generate MATLAB scripts, providing an option to alter code manually. The analysis of two-dimensional spectra (1H,13C-HSQC spectra) is facilitated by the use of a spectral library derived from publicly available databases which can be extended readily. The software allows to display specific metabolites in small regions of interest where signals can be picked. To facilitate the analysis of series of two-dimensional spectra, different spectra can be overlaid and assignments can be transferred between spectra. The software includes mechanisms to account for overlapping signals by highlighting neighboring and ambiguous assignments.\ud
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Conclusions\ud
The MetaboLab software is an integrated software package for NMR data processing and analysis, closely linked to the previously developed NMRLab software. It includes tools for batch processing and gives access to a wealth of algorithms available in the MATLAB framework. Algorithms within MetaboLab help to optimize the flow of metabolomics data preparation for statistical analysis. The combination of an intuitive graphical user interface along with advanced data processing algorithms facilitates the use of MetaboLab in a broader metabolomics context.\ud
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Heat shock protein expression during gametogenesis and embryogenesis.
When cells are subjected to various stress factors, they increase the production of a group of proteins called heat shock proteins (hsp). Heat shock proteins are highly conserved proteins present in organisms ranging from bacteria to man. Heat shock proteins enable cells to survive adverse environmental conditions by preventing protein denaturation. Thus the physiological and pathological potential of hsps is enormous and has been studied widely over the past two decades. The presence or absence of hsps influences almost every aspect of reproduction. They are among the first proteins produced during mammalian embryo development. In this report, the production of hsps in gametogenesis and early embryo development is described. It has been suggested that prolonged and asymptomatic infections trigger immunity to microbial hsp epitopes that are also expressed in man. This may be relevant for human reproduction, since many couples with fertility problems have had a previous genital tract infection. Antibodies to bacterial and human hsps are present at high titers in sera of many patients undergoing in vitro fertilization. In a mouse embryo culture model, these antibodies impaired the mouse embryo development at unique developmental stages. The gross morphology of these embryos resembled cells undergoing apoptosis. The TUNEL (terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling) staining pattern, which is a common marker of apoptosis, revealed that embryos cultured in the presence of hsp antibodies stained TUNEL-positive more often than unexposed embryos. These data extend preexisting findings showing the detrimental effect of immune sensitization to hsps on embryo development
Prominin-1+/CD133+ bone marrow-derived heart-resident cells suppress experimental autoimmune myocarditis
AIMS: Experimental autoimmune myocarditis (EAM) is a CD4(+) T cell-mediated mouse model of inflammatory heart disease. Tissue-resident bone marrow-derived cells adopt different cellular phenotypes depending on the local milieu. We expanded a specific population of bone marrow-derived prominin-1-expressing progenitor cells (PPC) from healthy heart tissue, analysed their plasticity, and evaluated their capacity to protect mice from EAM and heart failure. METHODS AND RESULTS: PPC were expanded from healthy mouse hearts. Analysis of CD45.1/CD45.2 chimera mice confirmed bone marrow origin of PPC. Depending on in vitro culture conditions, PPC differentiated into macrophages, dendritic cells, or cardiomyocyte-like cells. In vivo, PPC acquired a cardiac phenotype after direct injection into healthy hearts. Intravenous injection of PPC into myosin alpha heavy chain/complete Freund's adjuvant (MyHC-alpha/CFA)-immunized BALB/c mice resulted in heart-specific homing and differentiation into the macrophage phenotype. Histology revealed reduced severity scores for PPC-treated mice compared with control animals [treated with phosphate-buffered saline (PBS) or crude bone marrow at day 21 after MyHC-alpha/CFA immunization]. Echocardiography showed preserved fractional shortening and velocity of circumferential shortening in PPC but not PBS-treated MyHC-alpha/CFA-immunized mice. In vitro and in vivo data suggested that interferon-gamma signalling on PPC was critical for nitric oxide-mediated suppression of heart-specific CD4(+) T cells. Accordingly, PPC from interferon-gamma receptor-deficient mice failed to protect MyHC-alpha/CFA-immunized mice from EAM. CONCLUSION: Prominin-1-expressing, heart-resident, bone marrow-derived cells combine high plasticity, T cell-suppressing capacity, and anti-inflammatory in vivo effect
Regulatory limits for pesticide residues in water (IUPAC Technical Report)
National governments introduced residue limits and guideline levels forpesticide residues in water when policies were implemented to minimize the con-tamination of ground and surface waters. Initially, the main attention was given todrinking water.Regulatory limits for pesticide residues in waters should have the followingcharacteristics: definition of the type of water, definition of the residue, a suitableanalytical method for the residues, and explanation for the basis for each limit. Limits may be derived by applying a safety factor to a no-effect-level, orfrom levels occurring when good practices are followed and also passing a safetyassessment, or from the detection limit of an analytical method, or directly by leg-islative decision
Initial Results from the CHOOZ Long Baseline Reactor Neutrino Oscillation Experiment
Initial results are presented from CHOOZ, a long-baseline reactor-neutrino
vacuum-oscillation experiment. Electron antineutrinos were detected by a liquid
scintillation calorimeter located at a distance of about 1 km. The detector was
constructed in a tunnel protected from cosmic rays by a 300 MWE rock
overburden. This massive shielding strongly reduced potentially troublesome
backgrounds due to cosmic-ray muons, leading to a background rate of about one
event per day, more than an order of magnitude smaller than the observed
neutrino signal. From the statistical agreement between detected and expected
neutrino event rates, we find (at 90% confidence level) no evidence for
neutrino oscillations in the electron antineutrino disappearance mode for the
parameter region given approximately by deltam**2 > 0.9 10**(-3) eV**2 for
maximum mixing and (sin(2 theta)**2) > 0.18 for large deltam**2.Comment: 13 pages, Latex, submitted to Physics Letters
Limits on Neutrino Oscillations from the CHOOZ Experiment
We present new results based on the entire CHOOZ data sample. We find (at 90%
confidence level) no evidence for neutrino oscillations in the anti_nue
disappearance mode, for the parameter region given by approximately Delta m**2
> 7 x 10**-4 eV^2 for maximum mixing, and sin**2(2 theta) = 0.10 for large
Delta m**2. Lower sensitivity results, based only on the comparison of the
positron spectra from the two different-distance nuclear reactors, are also
presented; these are independent of the absolute normalization of the anti_nue
flux, the cross section, the number of target protons and the detector
efficiencies.Comment: 19 pages, 11 figures, Latex fil
Search for neutrino oscillations on a long base-line at the CHOOZ nuclear power station
This final article about the CHOOZ experiment presents a complete description
of the electron antineutrino source and detector, the calibration methods and
stability checks, the event reconstruction procedures and the Monte Carlo
simulation. The data analysis, systematic effects and the methods used to reach
our conclusions are fully discussed. Some new remarks are presented on the
deduction of the confidence limits and on the correct treatment of systematic
errors.Comment: 41 pages, 59 figures, Latex file, accepted for publication by
Eur.Phys.J.
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