562 research outputs found
Particle-Based Monte-Carlo Simulations of Steady-State Mass Transport at Intermediate Péclet Numbers
Conventional approaches for simulating steady-state distributions of dilute particles under diffusive and advective transport involve solving the diffusion and advection equations in at least two dimensions. Here, we present an alternative computational strategy by combining a particle-based rather than a field-based approach with the initialisation of particles in proportion to their flux. This method allows accurate prediction of the steady state and is applicable even at intermediate and high Péclet numbers (Pe>1) swhere traditional particle-based Monte-Carlo methods starting from randomly initialised particle distributions fail. We demonstrate that generating a flux of particles according to a predetermined density and velocity distribution at a single fixed time and initial location allows for accurate simulation of mass transport under flow. Specifically, upon initialisation in proportion to their flux, these particles are propagated individually and detected by summing up their Monte-Carlo trajectories in predefined detection regions. We demonstrate quantitative agreement of the predicted concentration profiles with the results of experiments performed with fluorescent particles in microfluidic channels under continuous flow. This approach is computationally advantageous and readily allows non-trivial initial distributions to be considered. In particular, this method is highly suitable for simulating advective and diffusive transport in microfluidic devices, for instance in the context of diffusive sizing.Financial support from the Biotechnology and Biological Sciences Research Council (BBSRC), the European Research Council (ERC), the Frances and Augustus Newman Foundation as well as the Swiss National Science Foundation is gratefully acknowledged
An optimized resilient advance bandwidth scheduling for media delivery services
Part 3: Evaluation and Experimental Study of Rich Network ServicesInternational audienceIn IP-based media delivery services, we often deal with predictable network load and traffic, making it beneficial to use advance reservations even when network failure occurs. In such a network, to offer reliable reservations, fault-tolerance related features should be incorporated in the advance reservation system. In this paper, we propose an optimized protection mechanism in which backup paths are selected in advance to protect the transfers when any failure happens in the network. Using a shared backup path protection, the proposed approach minimizes the backup capacity of the requests while guaranteeing 100% single link failure recovery. We have evaluated the quality and complexity of our proposed solution and the impact of different percentages of backup demands and timeslot sizes have been investigated in depth. The presented approach has been compared to our previously-designed algorithm as a baseline. Our simulation results reveal a noticeable improvement in request acceptance rate, up to 9.2%. Moreover, with fine-grained timeslot sizes and under limited network capacity, the time complexity of the proposed solution is up to 14% lower
Nuclear localization of the mitochondrial factor HIGD1A during metabolic stress.
Cellular stress responses are frequently governed by the subcellular localization of critical effector proteins. Apoptosis-inducing Factor (AIF) or Glyceraldehyde 3-Phosphate Dehydrogenase (GAPDH), for example, can translocate from mitochondria to the nucleus, where they modulate apoptotic death pathways. Hypoxia-inducible gene domain 1A (HIGD1A) is a mitochondrial protein regulated by Hypoxia-inducible Factor-1α (HIF1α). Here we show that while HIGD1A resides in mitochondria during physiological hypoxia, severe metabolic stress, such as glucose starvation coupled with hypoxia, in addition to DNA damage induced by etoposide, triggers its nuclear accumulation. We show that nuclear localization of HIGD1A overlaps with that of AIF, and is dependent on the presence of BAX and BAK. Furthermore, we show that AIF and HIGD1A physically interact. Additionally, we demonstrate that nuclear HIGD1A is a potential marker of metabolic stress in vivo, frequently observed in diverse pathological states such as myocardial infarction, hypoxic-ischemic encephalopathy (HIE), and different types of cancer. In summary, we demonstrate a novel nuclear localization of HIGD1A that is commonly observed in human disease processes in vivo
The relationship between the insulin-like growth factor-1 axis, weight loss, an inflammation-based score and survival in patients with inoperable non-small cell lung cancer
<b>Background & aims:</b>
The involvement of a systemic inflammatory response, as evidenced by the Glasgow Prognostic Score (GPS), is associated with weight loss and poor outcome in patients with non-small cell lung cancer. There is good evidence that nutritional and functional decline in patients with advanced malignant disease is associated with catabolic changes in metabolism. However, defects in anabolism may also contribute towards nutritional decline in patients with cancer. The aim of the present study was to examine the relationship between IGF-1 and IGFBP-3, performance status, mGPS and survival in patients with inoperable NSCLC.
<b>Methods:</b>
56 patients with inoperable NSCLC were studied. The plasma concentrations of IGF-1, IGFBP-3 and leptin were measured using ELISA and RIA.
<b>Results:</b>
The patients were predominantly male (61%), over 60 years old (80%), with advanced (stage III or IV) disease (98%), with a BMI≥20 (84%), an ECOG-ps of 0 or 1 (79%), a haemoglobin (59%) and white cell count (79%) in the reference range. On follow-up 43 patients died of their cancer. On univariate analysis, BMI (p<0.05), Stage (p<0.05), ECOG-ps (p<0.05), haemoglobin (p<0.05), white cell count (p<0.05) and mGPS (p<0.05) were associated with cancer specific survival. There was no association between age, sex, treatment, IGF-1, IGFBP-3, IGF-1:IGFBP-3 ratio, or leptin and cancer specific survival. With an increasing mGPS concentrations of haemoglobin (p<0.005) and IGFBP-3 (p<0.05) decreased. mGPS was not associated with either IGF-1(p>0.20), or leptin (p>0.20).
<b>Conclusions:</b>
In summary, the results of this study suggest that anabolism (IGF-1 axis) does not play a significant role in the relationship between nutritional and functional decline, systemic inflammation and poor survival in patients with inoperable NSCLC
Endovascular Therapy vs Medical Management for Patients With Acute Stroke With Medium Vessel Occlusion in the Anterior Circulation
Importance Randomized clinical trials have shown the efficacy of endovascular therapy (EVT) for acute large vessel occlusion strokes. The benefit of EVT in acute stroke with distal, medium vessel occlusion (DMVO) remains unclear.
Objective To examine the efficacy and safety outcomes associated with EVT in patients with primary DMVO stroke when compared with a control cohort treated with medical management (MM) alone.
Design, Setting, and Participants This multicenter, retrospective cohort study pooled data from patients who had an acute stroke and a primary anterior circulation emergency DMVO, defined as any segment of the anterior cerebral artery (ACA) or distal middle cerebral artery, between January 1, 2015, and December 31, 2019. Those with a concomitant proximal occlusion were excluded. Outcomes were compared between the 2 treatment groups using propensity score methods. Data analysis was performed from March to June 2021.
Exposures Patients were divided into EVT and MM groups.
Main Outcomes and Measures Main efficacy outcomes included 3-month functional independence (modified Rankin Scale [mRS] scores, 0-2) and 3-month excellent outcome (mRS scores, 0-1). Safety outcomes included 3-month mortality and symptomatic intracranial hemorrhage.
Results A total of 286 patients with DMVO were evaluated, including 156 treated with EVT (mean [SD] age, 66.7 [13.7] years; 90 men [57.6%]; median National Institute of Health Stroke Scale [NIHSS] score, 13.5 [IQR, 8.5-18.5]; intravenous tissue plasminogen activator [IV tPA] use, 75 [49.7%]; ACA involvement, 49 [31.4%]) and 130 treated with medical management (mean [SD] age, 69.8 [14.9] years; 62 men [47.7%]; median NIHSS score, 7.0 [IQR, 4.0-14.0], IV tPA use, 58 [44.6%]; ACA involvement, 31 [24.0%]). There was no difference in the unadjusted rate of 3-month functional independence in the EVT vs MM groups (151 [51.7%] vs 124 [50.0%]; P = .78), excellent outcome (151 [38.4%] vs 123 [31.7%]; P = .25), or mortality (139 [18.7%] vs 106 [11.3%]; P = .15). The rate of symptomatic intracranial hemorrhage was similar in the EVT vs MM groups (weighted: 4.0% vs 3.1%; P = .90). In inverse probability of treatment weighting propensity analyses, there was no significant difference between groups for functional independence (adjusted odds ratio [aOR], 1.36; 95% CI, 0.84-2.19; P = .20) or mortality (aOR, 1.24; 95% CI, 0.63-2.43; P = .53), whereas the EVT group had higher odds of an excellent outcome (mRS scores, 0-1) at 3 months (aOR, 1.71; 95% CI, 1.02-2.87; P = .04).
Conclusions and Relevance The findings of this multicenter cohort study suggest that EVT may be considered for selected patients with ACA or distal middle cerebral artery strokes. Further larger randomized investigation regarding the risk-benefit ratio for DMVO treatment is indicated
Modeling work practices under socio-technical systems for sustainable manufacturing performance
In light of the overwhelming consumption of resources by the manufacturing sector, this paper examined three key subsystems that are critical in greening the sector. Whereas the extant literature has focused on technological development to reduce environmental damage, it has not analyzed profoundly how manufacturing processes can be greened effectively. Hence, using carefully gathered data of 299 respondents and structural equation modeling, this paper sought to investigate the mediating effect of social, environmental, and technical subsystems on the relationship between management support and sustainable manufacturing performance. The results show that management support has a positive relationship with sustainable manufacturing performance (p < 0.005), while social, environmental, and technical subsystems partially mediate this relationship. Hence, efforts must be taken to encourage management of manufacturing firms to support sustainable management performance, while at the same time supporting them to introduce innovative social, environmental, and technical practices
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