144 resultados para suppression ratio
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Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Delta phi, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Delta phi dependence of jet yields in 0.14 nb(-1) of root s(NN) = 2.76 TeV Pb + Pb collisions at the LHC for jet transverse momenta p(T) > 45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Delta phi was characterized by the parameter, nu(jet)(2), and the ratio of out-of-plane (Delta phi similar to pi/2) to in-plane (Delta phi similar to 0) yields. Nonzero nu(jet)(2) values were measured in all centrality bins for p(T) < 160 GeV. The jet yields are observed to vary by as much as 20% between in-plane and out-of-plane directions.
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BACKGROUND CONTEXT In canine intervertebral disc (IVD) disease, a useful animal model, only little is known about the inflammatory response in the epidural space. PURPOSE To determine messenger RNA (mRNA) expressions of selected cytokines, chemokines, and matrix metalloproteinases (MMPs) qualitatively and semiquantitatively over the course of the disease and to correlate results to neurologic status and outcome. STUDY DESIGN/SETTING Prospective study using extruded IVD material of dogs with thoracolumbar IVD extrusion. PATIENT SAMPLE Seventy affected and 13 control (24 samples) dogs. OUTCOME MEASURES Duration of neurologic signs, pretreatment, neurologic grade, severity of pain, and outcome were recorded. After diagnostic imaging, decompressive surgery was performed. METHODS Messenger RNA expressions of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF), interferon (IFN)γ, MMP-2, MMP-9, chemokine ligand (CCL)2, CCL3, and three housekeeping genes was determined in the collected epidural material by Panomics 2.0 QuantiGene Plex technology. Relative mRNA expression and fold changes were calculated. Relative mRNA expression was correlated statistically to clinical parameters. RESULTS Fold changes of TNF, IL-1β, IL-2, IL-4, IL-6, IL-10, IFNγ, and CCL3 were clearly downregulated in all stages of the disease. MMP-9 was downregulated in the acute stage and upregulated in the subacute and chronic phase. Interleukin-8 was upregulated in acute cases. MMP-2 showed mild and CCL2 strong upregulation over the whole course of the disease. In dogs with severe pain, CCL3 and IFNγ were significantly higher compared with dogs without pain (p=.017/.020). Dogs pretreated with nonsteroidal anti-inflammatory drugs revealed significantly lower mRNA expression of IL-8 (p=.017). CONCLUSIONS The high CCL2 levels and upregulated MMPs combined with downregulated T-cell cytokines and suppressed pro-inflammatory genes in extruded canine disc material indicate that the epidural reaction is dominated by infiltrating monocytes differentiating into macrophages with tissue remodeling functions. These results will help to understand the pathogenic processes representing the basis for novel therapeutic approaches. The canine IVD disease model will be rewarding in this process.
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Stable carbon isotope analysis of methane (delta C-13 of CH4) on atmospheric samples is one key method to constrain the current and past atmospheric CH4 budget. A frequently applied measurement technique is gas chromatography (GC) isotope ratio mass spectrometry (IRMS) coupled to a combustion-preconcentration unit. This report shows that the atmospheric trace gas krypton (Kr) can severely interfere during the mass spectrometric measurement, leading to significant biases in delta C-13 of CH4, if krypton is not sufficiently separated during the analysis. According to our experiments, the krypton interference is likely composed of two individual effects, with the lateral tailing of the doubly charged Kr-86 peak affecting the neighbouring m/z 44 and partially the m/z 45 Faraday cups. Additionally, a broad signal affecting m/z 45 and especially m/z 46 is assumed to result from scattered ions of singly charged krypton. The introduced bias in the measured isotope ratios is dependent on the chromatographic separation, the krypton-to-CH4 mixing ratio in the sample, the focusing of the mass spectrometer as well as the detector configuration and can amount to up to several per mil in delta C-13. Apart from technical solutions to avoid this interference, we present correction routines to a posteriori remove the bias.
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BACKGROUND Interferon-α (IFN-α) treatment suppresses HIV-1 viremia and reduces the size of the HIV-1 latent reservoir. Therefore, investigation of the molecular and immunologic effects of IFN-α may provide insights that contribute to the development of novel prophylactic, therapeutic and curative strategies for HIV-1 infection. In this study, we hypothesized that microRNAs (miRNAs) contribute to the IFN-α-mediated suppression of HIV-1. To inform the development of novel miRNA-based antiretroviral strategies, we investigated the effects of exogenous IFN-α treatment on global miRNA expression profile, HIV-1 viremia, and potential regulatory networks between miRNAs and cell-intrinsic anti-HIV-1 host factors in vivo. METHODS Global miRNA expression was examined in longitudinal PBMC samples obtained from seven HIV/HCV-coinfected, antiretroviral therapy-naïve individuals before, during, and after pegylated interferon-α/ribavirin therapy (IFN-α/RBV). We implemented novel hybrid computational-empirical approaches to characterize regulatory networks between miRNAs and anti-HIV-1 host restriction factors. RESULTS miR-422a was the only miRNA significantly modulated by IFN-α/RBV in vivo (p<0.0001, paired t test; FDR<0.037). Our interactome mapping revealed extensive regulatory involvement of miR-422a in p53-dependent apoptotic and pyroptotic pathways. Based on sequence homology and inverse expression relationships, 29 unique miRNAs may regulate anti-HIV-1 restriction factor expression in vivo. CONCLUSIONS The specific reduction of miR-422a is associated with exogenous IFN-α treatment, and likely contributes to the IFN-α suppression of HIV-1 through the enhancement of anti-HIV-1 restriction factor expression and regulation of genes involved in programmed cell death. Moreover, our regulatory network analysis presents additional candidate miRNAs that may be targeted to enhance anti-HIV-1 restriction factor expression in vivo.
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BACKGROUND AND AIMS We investigated the association between significant liver fibrosis, determined by AST-to-platelet ratio index (APRI), and all-cause mortality among HIV-infected patients prescribed antiretroviral therapy (ART) in Zambia METHODS: Among HIV-infected adults who initiated ART, we categorized baseline APRI scores according to established thresholds for significant hepatic fibrosis (APRI ≥1.5) and cirrhosis (APRI ≥2.0). Using multivariable logistic regression we identified risk factors for elevated APRI including demographic characteristics, body mass index (BMI), HIV clinical and immunologic status, and tuberculosis. In the subset tested for hepatitis B surface antigen (HBsAg), we investigated the association of hepatitis B virus co-infection with APRI score. Using Kaplan-Meier analysis and Cox proportional hazards regression we determined the association of elevated APRI with death during ART. RESULTS Among 20,308 adults in the analysis cohort, 1,027 (5.1%) had significant liver fibrosis at ART initiation including 616 (3.0%) with cirrhosis. Risk factors for significant fibrosis or cirrhosis included male sex, BMI <18, WHO clinical stage 3 or 4, CD4+ count <200 cells/mm(3) , and tuberculosis. Among the 237 (1.2%) who were tested, HBsAg-positive patients had four times the odds (adjusted odds ratio, 4.15; 95% CI, 1.71-10.04) of significant fibrosis compared HBsAg-negatives. Both significant fibrosis (adjusted hazard ratio 1.41, 95% CI, 1.21-1.64) and cirrhosis (adjusted hazard ratio 1.57, 95% CI, 1.31-1.89) were associated with increased all-cause mortality. CONCLUSION Liver fibrosis may be a risk factor for mortality during ART among HIV-infected individuals in Africa. APRI is an inexpensive and potentially useful test for liver fibrosis in resource-constrained settings. This article is protected by copyright. All rights reserved.
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Heterodyne receivers at millimeter and submillimeter wavelength are widely used for radiometric spectral line observations for atmospheric remote sensing or radio astronomy. The quantitative analysis of such observations requires an accurate knowledge of the mixers's sideband ratio. In addition, its potential sensitivity to spurious harmonics needs to be well understood. In this paper, we discuss a measurement technique for these receiver characteristics, which is based on a scanning Martin Puplett Interferometer used in conjunction with a wide band digital autocorrelation spectrometer for the analysis of the intermediate frequency band. We present measurement results of different double sideband and sideband separating mixers, which were developed for the proposed 340GHz multi-beam limb sounder STEAMR.
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OBJECTIVE Cyclic recruitment and derecruitment of atelectasis can occur during mechanical ventilation, especially in injured lungs. Experimentally, cyclic recruitment and derecruitment can be quantified by respiration-dependent changes in PaO2 (ΔPaO2), reflecting the varying intrapulmonary shunt fraction within the respiratory cycle. This study investigated the effect of inspiration to expiration ratio upon ΔPaO2 and Horowitz index. DESIGN Prospective randomized study. SETTING Laboratory investigation. SUBJECTS Piglets, average weight 30 ± 2 kg. INTERVENTIONS At respiratory rate 6 breaths/min, end-inspiratory pressure (Pendinsp) 40 cm H2O, positive end-expiratory pressure 5 cm H2O, and FIO2 1.0, measurements were performed at randomly set inspiration to expiration ratios during baseline healthy and mild surfactant depletion injury. Lung damage was titrated by repetitive surfactant washout to induce maximal cyclic recruitment and derecruitment as measured by multifrequency phase fluorimetry. Regional ventilation distribution was evaluated by electrical impedance tomography. Step changes in airway pressure from 5 to 40 cm H2O and vice versa were performed after lavage to calculate PO2-based recruitment and derecruitment time constants (TAU). MEASUREMENTS AND MAIN RESULTS In baseline healthy, cyclic recruitment and derecruitment could not be provoked, whereas in model acute respiratory distress syndrome, the highest ΔPaO2 were routinely detected at an inspiration to expiration ratio of 1:4 (range, 52-277 torr [6.9-36.9 kPa]). Shorter expiration time reduced cyclic recruitment and derecruitment significantly (158 ± 85 torr [21.1 ± 11.3 kPa] [inspiration to expiration ratio, 1:4]; 25 ± 12 torr [3.3 ± 1.6 kPa] [inspiration to expiration ratio, 4:1]; p < 0.0001), whereas the PaO2/FIO2 ratio increased (267 ± 50 [inspiration to expiration ratio, 1:4]; 424 ± 53 [inspiration to expiration ratio, 4:1]; p < 0.0001). Correspondingly, regional ventilation redistributed toward dependent lung regions (p < 0.0001). Recruitment was much faster (TAU: fast 1.6 s [78%]; slow 9.2 s) than derecruitment (TAU: fast 3.1 s [87%]; slow 17.7 s) (p = 0.0078). CONCLUSIONS Inverse ratio ventilation minimizes cyclic recruitment and derecruitment of atelectasis in an experimental model of surfactant-depleted pigs. Time constants for recruitment and derecruitment, and regional ventilation distribution, reflect these findings and highlight the time dependency of cyclic recruitment and derecruitment.
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Etomidate is an intravenous hypnotic with a favourable clinical profile in haemodynamic high-risk scenarios. Currently, there is an active debate about the clinical significance of the drug's side effects and its overall risk-benefit ratio. Etomidate-induced transient adrenocortical suppression is well documented and has been associated with increased mortality in sepsis. In surgical patients at risk of hypotensive complications, however, a review of current literature provides no robust evidence to contraindicate a single-bolus etomidate induction. Large randomised controlled trials as well as additional observational data are required to compare safety of etomidate and its alternatives.
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The relationship between facial shape and attractiveness has been extensively studied, yet few studies have investigated the underlying biological factors of an attractive face. Many researchers have proposed a link between female attractiveness and sex hormones, but there is little empirical evidence in support this assumption. In the present study we investigated the relationship between circulating sex hormones and attractiveness. We created prototypes by separately averaging photographs of 15 women with high and low levels of testosterone, estradiol, and testosterone-to-estradiol ratio levels, respectively. An independent set of facial images was then shape transformed toward these prototypes. We paired the resulting images in such a way that one face depicted a female with high hormone level and the other a low hormone level. Fifty participants were asked to choose the more attractive face of each pair. We found that low testosterone-to-estradiol ratio and low testosterone were positively associated with female facial attractiveness. There was no preference for faces with high estradiol levels. In an additional experiment with 36 participants we confirmed that a low testosterone-to-estradiol ratio plays a larger role than low testosterone alone. These results provide empirical evidence that an attractive female face is shaped by interacting effects of testosterone and estradiol.
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We report on a comprehensive signal processing procedure for very low signal levels for the measurement of neutral deuterium in the local interstellar medium from a spacecraft in Earth orbit. The deuterium measurements were performed with the IBEX-Lo camera on NASA’s Interstellar Boundary Explorer (IBEX) satellite. Our analysis technique for these data consists of creating a mass relation in three-dimensional time of flight space to accurately determine the position of the predicted D events, to precisely model the tail of the H events in the region where the H tail events are near the expected D events, and then to separate the H tail from the observations to extract the very faint D signal. This interstellar D signal, which is expected to be a few counts per year, is extracted from a strong terrestrial background signal, consisting of sputter products from the sensor’s conversion surface. As reference we accurately measure the terrestrial D/H ratio in these sputtered products and then discriminate this terrestrial background source. During the three years of the mission time when the deuterium signal was visible to IBEX, the observation geometry and orbit allowed for a total observation time of 115.3 days. Because of the spinning of the spacecraft and the stepping through eight energy channels the actual observing time of the interstellar wind was only 1.44 days. With the optimised data analysis we found three counts that could be attributed to interstellar deuterium. These results update our earlier work.
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Anticipatory cognitive stress appraisal (ACSA) can affect the stress-induced release of stress hormones, which, in turn, can modulate microbicidal potential of macrophages. This study examines whether ACSA modulates wound-induced activation of macrophage microbicidal potential in 22 acutely stressed compared to 17 nonstressed healthy men. After catheter-induced wound infliction and completing the ACSA questionnaire, the stress group underwent an acute mental stress task, while the nonstressed group did not. Macrophage microbicidal potential and stress hormones were repeatedly measured. In acutely stressed men, but not in nonstressed men, higher scores in ACSA related to lower macrophage microbicidal potential. This association was statistically mediated by the norepinephrine (NE) stress response. Our data suggest that ACSA modulates stress-induced suppression of wound-induced macrophage activation and that the NE stress response underlies this effect.