Search results for "tolerance"
showing 10 items of 956 documents
Heart rate response and functional capacity in patients with chronic heart failure with preserved ejection fraction
2018
Aims The mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF) are not yet elucidated. Chronotropic incompetence has emerged as a potential mechanism. We aimed to evaluate whether heart rate (HR) response to exercise is associated to functional capacity in patients with symptomatic HFpEF. Methods and results We prospectively studied 74 HFpEF patients [35.1% New York Heart Association Class III, 53% female, age (mean ± standard deviation) 72.5 ± 9.1 years, and 59.5% atrial fibrillation]. Functional performance was assessed by peak oxygen consumption (peak VO2 ). The mean (standard deviation) peak VO2 was 10 ± 2.8 mL/min/kg. The following chronotropic pa…
NFAT transcription factors in control of peripheral T cell tolerance.
2006
The Ca++-regulated calcineurin/NFAT cascade is one of the crucial signalling pathways that controls adaptive immunity. However, a number of novel experimental data suggest that, in addition to their role in T cell activation, NFATc transcription factors play also a decisive role in the generation of peripheral tolerance against self-antigens. This function of NFATc factors is mediated by controlling activation-induced cell death and clonal anergy of T helper cells and the activity of regulatory T cells. The multi-functional role of NFATc proteins characterize these transcription factors as key regulators of immunological tolerance and, if dysregulated, of development of autoimmune diseases.
Tolerance towards resident intestinal flora in mice is abrogated in experimental colitis and restored by treatment with interleukin-10 or antibodies …
1996
There is now increasing evidence that hyperresponsiveness towards intestinal flora is a crucial event in the pathogenesis of inflammatory bowel disease (IBD). In support of this hypothesis, we recently described in humans that tolerance exists towards indigenous intestinal flora but is broken in active IBD lesions. In the present study, we have attempted to transfer this model into mice from different genetic backgrounds (BALB/c, SJL/J, C3H/HeJ). We found that mononuclear cells from spleen, small bowel and large bowel of mice do not proliferate, i.e. are tolerant when exposed to bacterial sonicates derived from autologous intestine (BsA) but do proliferate, i.e. are immune when exposed to b…
Fault Injection into VHDL Models: Experimental Validation of a Fault-Tolerant Microcomputer System
1999
This work presents a campaign of fault injection to validate the dependability of a fault tolerant microcomputer system. The system is duplex with cold stand-by sparing, parity detection and a watchdog timer. The faults have been injected on a chip-level VHDL model, using an injection tool designed with this purpose. We have carried out a set of injection experiments (with 3000 injections each), injecting transient and permanent faults of types stuck-at, open-line and indetermination on both the signals and variables of the system, running a workload. We have analysed the pathology of the propagated errors, measured their latency, and calculated both detection and recovery coverage. We have…
Reducing False Node Failure Predictions in HPC
2019
Future HPC applications must be able to scale to thousands of compute nodes, while running for several days. The increased runtime and node count inconveniently raises the probability of hardware failures that may interrupt computations. Scientists must therefore protect their simulations against hardware failures. This is typically done using frequent checkpoint& restart, which may have significant overheads. Consequently, the frequency in which checkpoints are taken should be minimized. Predicting hardware failures ahead of time is a promising approach to address this problem, but has remaining issues like false alarms at large scales. In this paper, we introduce the probability of unnece…
A survey on data center network topologies
2018
Data centers are the infrastructures that support the cloud computing services. So, their topologies have an important role on controlling the performance of these services. Designing an efficient topology with a high scalability and a good network performance is one of the most important challenges in data centers. This paper surveys recent research advances linked to data center network topologies. We review some representative topologies and discuss their proprieties in details. We compare them in terms of average path length, network fault tolerance, scalability and connection pattern techniques. Springer Nature Switzerland AG 2018. Acknowledgment. This publication was made possible by …
MSS: A Multi-Level Data Placement Scheme for Data Survival in Wireless Sensor Networks
2009
In recently popularized unattended wireless sensor networks, sensed data are stored locally or some designated nodes for a long term and retrieved sometime by collectors on demand. Such data may be delete or modified as sensor nodes are always exposed to risks such as random failure and mobile adversary. To maximize the data survival, we propose a secure and efficient scheme - MSS. MSS makes use of hopbounded computational secret sharing to achieve fault tolerance and compromise resilience, and takes advantages of multi-level secret sharing to mitigate communication overhead and improve overall security. MSS has the most advantages in terms of security and efficiency among presented schemes…
PTNet: A parameterizable data center network
2016
This paper presents PTNet, a new data center topology that is specifically designed to offer a high and parameterized scalability with just one layer architecture. Furthermore, despite its high scalability, PTNet grants a reduced latency and a high performance in terms of capacity and fault tolerance. Consequently, compared to widely known data center networks, our new topology shows better capacity, robustness, cost-effectiveness and less power consumption. Conducted experiments and theoretical analyses illustrate the performance of the novel system. 2016 IEEE. Scopus
Short-term walking physical training and changes in body hydration status, B-type natriuretic peptide and C-reactive protein levels in compensated co…
2008
BACKGROUND: Congestive heart failure (CHF) is associated with decreased exercise tolerance, alterations in body fluid balance and activation of neurohumoral and inflammatory pathways. Physical training, despite the contraindications of the past, is recommended for its beneficial effects on exercise capacity and quality of life. We investigate the effects of a short-term (ten weeks) walking physical training program (PT) on body hydration state (HS), B-type natriuretic peptide (BNP) and C-reactive protein (CRP) levels. METHODS AND RESULTS: 22 patients with CHF (mean age 62.7+/-4.8 years, 15 men, mean ejection fraction 38.9+/-3.6%, NYHA class II-III), were enrolled. Eleven patients were rando…
Robust fault tolerant tracking controller design for a VTOL aircraft
2013
This paper deals with the fault tolerant control (FTC) design for a Vertical Takeoff and Landing (VTOL) aircraft subject to external disturbances and actuator faults. The aim is to synthesize a fault tolerant controller ensuring trajectory tracking for the nonlinear uncertain system represented by a Takagi-Sugeno (T-S) model. In order to design the FTC law, a proportional integral observer (PIO) is adopted which estimate both of the faults and the faulty system states. Based on the Lyapunov theory and ℓ2 optimization, the trajectory tracking performance and the stability of the closed loop system are analyzed. Sufficient conditions are obtained in terms of linear matrix inequalities (LMI). …