7,371 research outputs found
An absorption spectrum amplifier for determining gas composition
Compositions of gas samples are frequently studied by laser absorption spectroscopy. Sensitivity is improved by two orders of magnitude when absorption cell is placed inside an organic-dye laser cavity
Moments of Wigner function and Renyi entropies at freeze-out
Relation between Renyi entropies and moments of the Wigner function,
representing the quantum mechanical description of the M-particle
semi-inclusive distribution at freeze-out, is investigated. It is shown that in
the limit of infinite volume of the system, the classical and quantum
descriptions are equivalent. Finite volume corrections are derived and shown to
be small for systems encountered in relativistic heavy ion collisions.Comment: 15 pages, one figur
The anomalous threshold, confinement, and an essential singularity in the heavy-light form factor
The analytic behavior of the heavy-light meson form factor is investigated
using several relativistic examples including unconfined, weakly confined, and
strongly confined mesons. It is observed that confinement erases the anomalous
threshold singularity and also induces an essential singularity at the normal
annihilation threshold. In the weak confinement limit, the "would be" anomalous
threshold contribution is identical to that of the real singularity on its
space-like side.Comment: Latex 2.09 with epsf.sty. 24 pages of text and 8 postscript figures.
Postscript version of complete paper will also be available soon at
http://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-983 or at
ftp://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-98
Association of serum levels of lipoprotein A-I and lipoprotein A-I/A-II with high on-treatment platelet reactivity in patients with ST-segment elevation myocardial infarction
Objective: High-density lipoproteins (HDLs) are a very heterogeneous group of particles. Little is known about the impact of their subfractions including lipoprotein A-I (LpA-I) and lipoprotein A-I/A-II (LpA-I/A-II) on platelet function and high on-treatment platelet reactivity (HPR), particularly in the acute phase of ST-segment elevation myocardial infarction (STEMI). The aim of the study was to evaluate the relationship between serum levels of LpA-I and LpA-I/A-II and HPR in STEMI patients. Methods: Fifty-two consecutive STEMI patients (26.9% women, mean age 60.6±9.1 years) were enrolled into this study. Clinical and demographic data were collected and HDL subfractions were measured by rocket immunoelectrophoresis. Platelet reactivity was assessed using light transmission aggregometry and quantitative flow cytometry. Results: We found a positive correlation between platelet aggregation after both ADP-5 and ADP-20 stimulation and serum level of LpA-I. Compared with subjects with satisfactory platelet response to clopidogrel, patients with HPR had 32.44% higher serum level of LpA-I (p=0.021). On the other hand, patients with HPR assessed by ADP-5 stimulation had 22.13% lower serum level of LpA-I/A-II (p=0.040). Regression analysis showed that LpA-I [odds ratio (OR) 1.03; 95% confidence interval (CI) 1-1.07; p=0.049] and current smoking (OR 0.18; 95% CI 0.04-0.81; p=0.025) were independent predictors of HPR. With receiver operating characteristic (ROC) curve analysis, we designated the cut-off point at serum level of 57.52 mg/dL for LpA-I for predicting HPR (AUC=0.71, p=0.010). Conclusion: This study showed that higher serum level of LpA-I measured in the acute phase of STEMI is an independent risk factor for HPR. Our study is the first to demonstrate an important and distinct activity of LpA-I and LpA-I/A-II that can prove pleiotropic and different functions of HDL subfractions in acute STEMI. (Anatol J Cardiol 2018; 19: 374-81
Baseline design of a sorption-based Joule-Thomson cooler chain for the METIS instrument in the E-ELT
METIS, the Mid-Infrared E-ELT Imager and Spectrograph, is one of the proposed instruments in E-ELT (European Extremely Large Telescope). Its infrared detectors require multiple operating temperatures below 77 K. Therefore, active coolers have to be deployed to provide sub-liquid-nitrogen (sub-LN2) temperature cooling. However, the sensitive imaging optical detecting system also demands very low levels of vibration. Thus, the University of Twente proposed a vibration-free cooling technique based on physical sorption. In this paper, we describe the baseline design of such a sorption-based Joule-Thomson cooler chain for the METIS instrument, that is able to deliver cooling powers of 0.4 W at 8 K, 1.1 W at 25 K and 1.4 W at 40 K from a 70-K heat sinking. This design is based on working fluid selection, cascading cooler stages and operating parameter optimization. Also, the performance of the resulting cooler design is analyzed
Neonatal-onset multisystem inflammatory disease responsive to interleukin-1 beta inhibition
BACKGROUND:Neonatal-onset multisystem inflammatory disease is characterized by fever, urticarial rash, aseptic meningitis, deforming arthropathy, hearing loss, and mental retardation. Many patients have mutations in the cold-induced autoinflammatory syndrome 1 (CIAS1) gene, encoding cryopyrin, a protein that regulates inflammation.METHODS:We selected 18 patients with neonatal-onset multisystem inflammatory disease (12 with identifiable CIAS1 mutations) to receive anakinra, an interleukin-1-receptor antagonist (1 to 2 mg per kilogram of body weight per day subcutaneously). In 11 patients, anakinra was withdrawn at three months until a flare occurred. The primary end points included changes in scores in a daily diary of symptoms, serum levels of amyloid A and C-reactive protein, and the erythrocyte sedimentation rate from baseline to month 3 and from month 3 until a disease flare.RESULTS:All 18 patients had a rapid response to anakinra, with disappearance of rash. Diary scores improved (P<0.001) and serum amyloid A (from a median of 174 mg to 8 mg per liter), C-reactive protein (from a median of 5.29 mg to 0.34 mg per deciliter), and the erythrocyte sedimentation rate decreased at month 3 (all P<0.001), and remained low at month 6. Magnetic resonance imaging showed improvement in cochlear and leptomeningeal lesions as compared with baseline. Withdrawal of anakinra uniformly resulted in relapse within days; retreatment led to rapid improvement. There were no drug-related serious adverse events.CONCLUSIONS:Daily injections of anakinra markedly improved clinical and laboratory manifestations in patients with neonatal-onset multisystem inflammatory disease, with or without CIAS1 mutations
Four-photon interference: a realizable experiment to demonstrate violation of EPR postulates for perfect correlations
Bell's theorem reveals contradictions between the predictions of quantum
mechanics and the EPR postulates for a pair of particles only in situations
involving imperfect statistical correlations. However, with three or more
particles, contradictions emerge even for perfect correlations. We describe an
experiment which can be realized in the laboratory, using four-photon entangled
states generated by parametric down-conversion, to demonstrate this
contradiction at the level of perfect correlations.Comment: publishe
Zinc and zinc transporters in macrophages and their roles in efferocytosis in COPD
Our previous studies have shown that nutritional zinc restriction exacerbates airway inflammation accompanied by an increase in caspase-3 activation and an accumulation of apoptotic epithelial cells in the bronchioles of the mice. Normally, apoptotic cells are rapidly cleared by macrophage efferocytosis, limiting any secondary necrosis and inflammation. We therefore hypothesized that zinc deficiency is not only pro-apoptotic but also impairs macrophage efferocytosis. Impaired efferocytic clearance of apoptotic epithelial cells by alveolar macrophages occurs in chronic obstructive pulmonary disease (COPD), cigarette-smoking and other lung inflammatory diseases. We now show that zinc is a factor in impaired macrophage efferocytosis in COPD. Concentrations of zinc were significantly reduced in the supernatant of bronchoalveolar lavage fluid of patients with COPD who were current smokers, compared to healthy controls, smokers or COPD patients not actively smoking. Lavage zinc was positively correlated with AM efferocytosis and there was decreased efferocytosis in macrophages depleted of Zn in vitro by treatment with the membrane-permeable zinc chelator TPEN. Organ and cell Zn homeostasis are mediated by two families of membrane ZIP and ZnT proteins. Macrophages of mice null for ZIP1 had significantly lower intracellular zinc and efferocytosis capability, suggesting ZIP1 may play an important role. We investigated further using the human THP-1 derived macrophage cell line, with and without zinc chelation by TPEN to mimic zinc deficiency. There was no change in ZIP1 mRNA levels by TPEN but a significant 3-fold increase in expression of another influx transporter ZIP2, consistent with a role for ZIP2 in maintaining macrophage Zn levels. Both ZIP1 and ZIP2 proteins were localized to the plasma membrane and cytoplasm in normal human lung alveolar macrophages. We propose that zinc homeostasis in macrophages involves the coordinated action of ZIP1 and ZIP2 transporters responding differently to zinc deficiency signals and that these play important roles in macrophage efferocytosis
- …