250 research outputs found
EEG-based cognitive control behaviour assessment: an ecological study with professional air traffic controllers
Several models defining different types of cognitive human behaviour are available. For this work, we
have selected the Skill, Rule and Knowledge (SRK) model proposed by Rasmussen in 1983. This model
is currently broadly used in safety critical domains, such as the aviation. Nowadays, there are no tools
able to assess at which level of cognitive control the operator is dealing with the considered task, that
is if he/she is performing the task as an automated routine (skill level), as procedures-based activity
(rule level), or as a problem-solving process (knowledge level). Several studies tried to model the SRK
behaviours from a Human Factor perspective. Despite such studies, there are no evidences in which such
behaviours have been evaluated from a neurophysiological point of view, for example, by considering
brain activity variations across the different SRK levels. Therefore, the proposed study aimed to
investigate the use of neurophysiological signals to assess the cognitive control behaviours accordingly
to the SRK taxonomy. The results of the study, performed on 37 professional Air Traffic Controllers,
demonstrated that specific brain features could characterize and discriminate the different SRK levels,
therefore enabling an objective assessment of the degree of cognitive control behaviours in realistic
setting
Predicting clinical outcomes using baseline and followâup laboratory data from the hepatitis C longâterm treatment against cirrhosis trial
Predicting clinical outcomes in patients with chronic hepatitis C is challenging. We used the hepatitis C longâterm treatment against cirrhosis (HALTâC) trial database to develop two models, using baseline values of routinely available laboratory tests together with changes in these values during followâup to predict clinical decompensation and liverârelated death/liver transplant in patients with advanced hepatitis C. Patients randomized to no treatment and who had â„2âyear followâup without a clinical outcome were included in the analysis. Four variables (platelet count, aspartate aminotransferase [AST]/alanine aminotransferase [ALT] ratio, total bilirubin, and albumin) with three categories of change (stable, mild, or severe) over 2 years were analyzed. Cumulative incidence of clinical outcome was determined by KaplanâMeier analysis and Cox regression was used to evaluate predictors of clinical outcome. In all, 470 patients with 60 events were used to develop models to predict clinical decompensation. Baseline values of all four variables were predictive of decompensation. There was a general trend of increasing outcomes with more marked worsening of laboratory values over 2 years, particularly for patients with abnormal baseline values. A model that included baseline platelet count, AST/ALT ratio, bilirubin, and severe worsening of platelet count, bilirubin, and albumin was the best predictor of clinical decompensation. A total of 483 patients with 79 events were used to evaluate predictors of liverârelated death or liver transplant. A model that included baseline platelet count and albumin as well as severe worsening of AST/ALT ratio and albumin was the best predictor of liverârelated outcomes. Conclusion: Both the baseline value and the rapidity in change of the value of routine laboratory variables were shown to be important in predicting clinical outcomes in patients with advanced chronic hepatitis C. (H EPATOLOGY 2011;)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88084/1/24550_ftp.pd
Human Factors and Neurophysiological Metrics in Air Traffic Control: a Critical Review
International audienceThis article provides the reader a focused and organised review of the research progresses on neurophysiological indicators, also called âneurometricsâ, to show how neurometrics could effectively address some of the most important Human Factors (HFs) needs in the Air Traffic Management (ATM) field. The state of the art on the most involved HFs and related cognitive processes (e.g. mental workload, cognitive training) is presented together with examples of possible applications in the current and future ATM scenarios, in order to better understand and highlight the available opportunities of such neuroscientific applications. Furthermore, the paper will discuss the potential enhancement that further research and development activities could bring to the efficiency and safety of the ATM service
How neurophysiological measures can be used to enhance the evaluation of remote tower solutions
International audienceNew solutions in operational environments are often, among objective measurements, evaluated by using subjective assessment and judgement from experts. Anyhow, it has been demonstrated that subjective measures suffer from poor resolution due to a high intra and inter operator variability. Also, performance measures, if available, could provide just partial information, since an operator could achieve the same performance but experiencing a different workload. In this study we aimed to demonstrate i) the higher resolution of neurophysiological measures in comparison to subjective ones, and ii) how the simultaneous employment of neurophysiological measures and behavioural ones could allow a holistic assessment of operational tools. In this regard, we tested the effectiveness of an EEG-based neurophysiological index (WEEG index) in comparing two different solutions (i.e. Normal and Augmented) in terms of experienced workload. In this regard, 16 professional Air Traffic Controllers (ATCOs) have been asked to perform two operational scenarios. Galvanic Skin Response (GSR) has also been recorded to evaluate the level of arousal (i.e. operator involvement) during the two scenarios execution. NASA-TLX questionnaire has been used to evaluate the perceived workload, and an expert was asked to assess performance achieved by the ATCOs. Finally, reaction times on specific operational events relevant for the assessment of the two solutions, have also been collected. Results highlighted that the Augmented solution induced a local increase in subjects performance (Reaction times). At the same time, this solution induced an increase in the workload experienced by the participants (WEEG). Anyhow, this increase is still acceptable, since it did not negatively impact the performance and has to be intended only as a consequence of the higher engagement of the ATCOs. This behavioural effect is totally in line with physiological results obtained in terms of arousal (GSR), that increased during the scenario with augmentation. Subjective measures (NASA-TLX) did not highlight any significant variation in perceived workload. These results suggest that neurophysiological measure provide additional information than behavioural and subjective ones, even at a level of few seconds, and its employment during the pre-operational activities (e.g. design process) could allow a more holistic and accurate evaluation of new solutions
Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation
BACKGROUND: Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established. OBJECTIVE: To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease. DATA SOURCES: We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists. METHODS: We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted. RESULTS: Given a cost-effectiveness threshold of ÂŁ20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of ÂŁ9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of ÂŁ28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (ÂŁ30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a ÂŁ20,000 threshold (ICER: ÂŁ19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of ÂŁ822. LIMITATIONS: A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments. CONCLUSIONS: Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD. STUDY REGISTRATION: This study is registered as PROSPERO CRD42011001561. FUNDING: The National Institute for Health Research Health Technology Assessment programme
Stromal Cell-Derived Factor-1/CXCL12 Contributes to MMTV-Wnt1 Tumor Growth Involving Gr1+CD11b+ Cells
BACKGROUND: Histological examinations of MMTV-Wnt1 tumors reveal drastic differences in the tumor vasculature when compared to MMTV-Her2 tumors. However, these differences have not been formally described, nor have any angiogenic factors been implicated to be involved in the Wnt1 tumors. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that MMTV-Wnt1 tumors were more vascularized than MMTV-Her2 tumors, and this correlated with significantly higher expression of a CXC chemokine, stromal cell-derived factor-1 (SDF1/CXCL12) but not with VEGFA. Isolation of various cell types from Wnt1 tumors revealed that SDF1 was produced by both tumor myoepithelial cells and stromal cells, whereas Her2 tumors lacked myoepithelial cells and contained significantly less stroma. The growth of Wnt1 tumors, but not Her2 tumors, was inhibited by a neutralizing antibody to SDF1, but not by neutralization of VEGFA. Anti-SDF1 treatment decreased the proportion of infiltrating Gr1(+) myeloid cells in the Wnt1 tumors, which correlated with a decrease in the percentage of endothelial cells. The involvement of Gr1(+) cells was evident from the retardation of Wnt1 tumor growth following in vivo depletion of these cells with an anti-Gr1-specific antibody. This degree of inhibition on Wnt1 tumor growth was comparable, but not additive, to the effect observed with anti-SDF1, indicative of overlapping mechanisms of inhibition. In contrast, Her2 tumors were not affected by the depletion of Gr1(+) cells. CONCLUSIONS/SIGNIFICANCE: We demonstrated that SDF1 is important for Wnt1, but not for HER2, in inducing murine mammary tumor and the role of SDF1 in tumorigenesis involves Gr1(+) myeloid cells to facilitate growth and/or angiogenesis
PTEN deficiency: a role in mammary carcinogenesis
The PTEN gene is often mutated in primary human tumors and cell lines, but the low rate of somatic PTEN mutation in human breast cancer has led to debate over the role of this tumor suppressor in this disease. The involvement of PTEN in human mammary oncogenesis has been implicated from studies showing that germline PTEN mutation in Cowden disease predisposes to breast cancer, the frequent loss of heterozygosity at the PTEN locus, and reduced PTEN protein levels in sporadic breast cancers. To assay the potential contribution of PTEN loss in breast tumor promotion, Li et al. [1] crossed Pten heterozygous mice with mouse mammary tumor virus-Wnt-1 transgenic (Wnt-1 TG, Pten+/-) mice. Mammary ductal carcinoma developed earlier in Wnt-1 TG, Pten+/- mice than in mice bearing either genetic change alone, and showed frequent loss of the remaining wild-type PTEN allele. These data indicate a role for PTEN in breast tumorigenesis in an in vivo model
Liver Enzyme Alterations in HCV-Monoinfected and HCV/HIV-Coinfected Patients
Hepatitis C virus (HCV) is the most common blood-borne infection in developed countries and co-infection with the Human Immunodeficiency Virus (HIV) is frequent in individuals with history of injecting drug use (IDU)
Apoptosis-like cell death in Leishmania donovani treated with KalsomeTM10, a new liposomal amphotericin B
The present study aimed to elucidate the cell death mechanism in Leishmania donovani upon treatment with KalsomeTM10, a new liposomal amphotericin B.
Methodology/Principal findings We studied morphological alterations in promastigotes through phase contrast and scanning electron microscopy. Phosphatidylserine (PS) exposure, loss of mitochondrial membrane potential and disruption of mitochondrial integrity was determined by flow cytometry using annexinV-FITC, JC-1 and mitotraker, respectively. For analysing oxidative stress,
generation of H2O2 (bioluminescence kit) and mitochondrial superoxide O2 â (mitosox) were
measured. DNA fragmentation was evaluated using terminal deoxyribonucleotidyl transferase mediated dUTP nick-end labelling (TUNEL) and DNA laddering assay. We found that
KalsomeTM10 is more effective then Ambisome against the promastigote as well as intracellular amastigote forms. The mechanistic study showed that KalsomeTM10 induced several morphological alterations in promastigotes typical of apoptosis. KalsomeTM10 treatment showed a dose- and time-dependent exposure of PS in promastigotes. Further,study on mitochondrial pathway revealed loss of mitochondrial membrane potential as well as disruption in mitochondrial integrity with depletion of intracellular pool of ATP. KalsomeTM10 treated promastigotes showed increased ROS production, diminished GSH levels and increased caspase-like activity. DNA fragmentation and cell cycle arrest was observed in KalsomeTM10 treated promastigotes. Apoptotic DNA fragmentation was also
observed in KalsomeTM10 treated intracellular amastigotes. KalsomeTM10 induced generation of ROS and nitric oxide leads to the killing of the intracellular parasites. Moreover, endocytosis is indispensable for KalsomeTM10 mediated anti-leishmanial effect in host
macrophag
A first test of CUPID prototypal light detectors with NTD-Ge sensors in a pulse-tube cryostat
CUPID is a next-generation bolometric experiment aiming at searching for
neutrinoless double-beta decay with ~250 kg of isotopic mass of Mo. It
will operate at 10 mK in a cryostat currently hosting a similar-scale
bolometric array for the CUORE experiment at the Gran Sasso National Laboratory
(Italy). CUPID will be based on large-volume scintillating bolometers
consisting of Mo-enriched LiMoO crystals, facing thin
Ge-wafer-based bolometric light detectors. In the CUPID design, the detector
structure is novel and needs to be validated. In particular, the CUORE cryostat
presents a high level of mechanical vibrations due to the use of pulse tubes
and the effect of vibrations on the detector performance must be investigated.
In this paper we report the first test of the CUPID-design bolometric light
detectors with NTD-Ge sensors in a dilution refrigerator equipped with a pulse
tube in an above-ground lab. Light detectors are characterized in terms of
sensitivity, energy resolution, pulse time constants, and noise power spectrum.
Despite the challenging noisy environment due to pulse-tube-induced vibrations,
we demonstrate that all the four tested light detectors comply with the CUPID
goal in terms of intrinsic energy resolution of 100 eV RMS baseline noise.
Indeed, we have measured 70--90 eV RMS for the four devices, which show an
excellent reproducibility. We have also obtained outstanding energy resolutions
at the 356 keV line from a Ba source with one light detector achieving
0.71(5) keV FWHM, which is -- to our knowledge -- the best ever obtained when
compared to detectors of any technology in this energy range.Comment: Prepared for submission to JINST; 16 pages, 7 figures, and 1 tabl
- âŠ