Finite volume analysis of temperature effects induced by active MRI implants: 2. Defects on active MRI implants causing hot spots

9106 Background: Most patients with advanced cancer want an idea of typical, best case, and worst case scenarios for overall survival (OS). Specific percentiles from OS curves of comparable patients are a reasonable starting point for estimating these scenarios. We summarized recent randomized trials to determine if simple multiples of the median OS from each curve provided reasonable estimates of these scenarios, and to determine the ratio of median OS to median PFS from corresponding curves. Methods: We searched the Cochrane register and major journals from 1999 to 2009 for randomized trials of first-line chemotherapy for MBC with ≥90 patients/arm. We recorded the median and following percentiles (represented scenario) from each OS curve: 90th (worst case), 75th (lower typical), 25th (upper typical) and 10th (best case). We estimated these percentiles for each OS curve by multiplying its median by the following simple multiples: 0.25 for the 90th, 0.5 for the 75th, 2 for the 25th, and 3 for the 10th. Each estimate was deemed accurate if within 0.75 to 1.33 times the actual value. Associations between trial characteristics and median OS were assessed with linear regression. Results: We analyzed 74 OS curves from 34 trials including 12,714 women followed for a median of 3 years. The average value (interquartile range, IQR) of the median OS was 22 months (18-24), of the median PFS was 7 months (6-9), and of the ratio of median OS to PFS was 3.0 (2.4-3.5). The average value (IQR) in months from all OS curves for each scenario was: worst case 6 (5-7), lower typical 12 (10-13), upper typical 36 (31-41) and best case 56 (47-60). Simple multiples of the median OS provided accurate estimates of the worst case in 75% of curves, lower typical in 97%, upper typical in 96% and best case in 96%. OS was longer in trials with a higher proportion of ER+ tumors (p=0.0018) and in trials of HER2+ women treated with trastuzumab (p=0.004). Conclusions: Worst, typical, and best case scenarios were remarkably consistent in a wide range of contemporary trials. Simple multiples of the median provided accurate estimates of these scenarios for most OS curves and are a good basis for discussing prognosis. No significant financial relationships to disclose.

A prestressed concrete cylinder pipe (PCCP) consists of a concrete core, a steel cylinder, prestressing wires, and a mortar coating. Most PCCP failures are related to the breakage of prestressing wires. It is thus expected that the load-bearing capacity of PCCP is significantly affected by the length of the prestress loss zone and the stress distribution in the broken wire. Based on a tri-linear bond-slip model, the length of prestress loss zone and the stress transfer mechanism between a broken wire and a mortar coating are analysed in this paper. During the breaking (unloading) process of a prestressing wire, the interfacial bondline exhibits the following three stages: elastic stage, elastic-softening stage, and elastic-softening-debonding stage. The closed-form solutions for the interfacial slip, the interfacial shear stress, and the axial stress in the broken wire are derived for each stage. The solutions are verified by the finite element predictions. A parametric study is presented to investigate the effects of the size of the prestressing wires, the prestressing level, the interfacial shear strength, and the residual interfacial shear strength on the interfacial stress transfer. For an example PCCP with an inner diameter of 4 m, the length of prestress loss zone increases from 500 mm to 3300 mm as the radius of prestressing wire increases from 1 mm to 7 mm. It increases from 2700 mm to 7700 mm when the interfacial shear strength reduces from 3.94 MPa to 0.62 MPa and reduces from 13,200 mm to 7300 mm as the residual interfacial shear stress factor increases from 0.1 to 0.9.

Hot spot locations and temperature distributions in a forced convection photochemical reactor

A dam break is a low-probability, high risk catastrophe event that is extremely destructive and has a substantial negative socio-economic impact on downstream and nearby areas. Simulating dam breach and analyzing flood propagation downstream from those events is vital for identifying and minimizing the risks associated downstream of dam location. This study is intended to anlayse the effect of overtopping failure of dam for two scenario (a) base-case scenario (scenario with average value of dam breach parameters from their range) and (b) worst case scenario (the breach with largest geometry, shortest formation time and highest peak outflow magnitude). Further, a hydrodyanmic modelling is perfomed to investigate the sensitivity analysis (local and global) of five dam breach parameters (dam breach elevation, dam breach width, breach formation time, weir coefficient, trigger failure elevation) on breach outflow in a proposed hydropower project located in Nepal. Aeronautical Reconnaissance Coverage Geographic Information System (ArcGIS), Hydraulic Engineering Center River Analysis System (HEC-RAS) and OriginPro 2022b are utilized to analyse the effect of dam breach and parameter sensitivity. Generation of outflow hydrograph shows that worst case scenario has devasting effect downstream with innudation of 1047 of househols and 50.83 kilometers of roads. The breach velocty was recorded as 15.16 m/s and 20.85 m/s for base and worst case respectively. The minimum depth and maximum depth of flooding downstream from dam location was found to be 24.51 m and 73.6 m for base case and 47.43 m and 106.75 m for worst case. Due to backwater effect at Bheri river, peak flow at 14 km downstream from dam reduces significantly to 124852.57 m3/s and 244204.41 m3/s for base and worst case respectively. From local sensitivty analysis it has been found that, dam breach elevation is more sensitive and triggering failure elevation is less sensitive for peak outflow hydrograph. Whereas, dam breach width seems more sensitive and TFE seems least sensitive for peak outflow using Monte Carlo Simulation for gloal sensitivity.

Mammals arousing from hibernation display pronounced regional heterothermy, where the thoracic and head regions warm faster than the abdominal and hindlimb regions. We used laser-Doppler flowmetry to measure peripheral hind foot blood flow during hibernation and arousal and gamma imaging of technetium-labeled albumin to measure whole blood volume distribution in hamsters arousing from hibernation. It was discovered that the hibernating hamster responds to physical but not to sound or hypercapnic stimulation with rapid, 73% reduction of hind foot blood flow. Hind foot blood flow vasoconstriction was maintained from the onset of arousal until late in arousal when rectal temperature was rapidly increased. alpha-Adrenergic blockade early in arousal increased hind foot blood flow by 700%, suggesting that vasoconstriction was mediated by activation of sympathetic tone. Gamma imaging revealed that, by the early phase of arousal from hibernation, the blood volume of the body below the liver is greatly reduced, whereas blood volumes of the thorax and head are much greater than corresponding volumes in anesthetized hamsters. As arousal progresses and cardiac activity increases and regional heterothermy develops, this regional blood volume distribution is largely maintained; however, blood volume slowly decreases in the thoracic region and slowly increases in the shoulder and head regions. The rapid increase in rectal temperature, characteristic of mid- to late- arousal phases, is probably mediated, in part, by reduction of adrenergic tone on abdominal and hindlimb vasculature. Warm blood then moves into the hind body, produces an increase in temperature, blood flow, and blood volume in the hind body and compensatory reductions of blood volume in the neck, head, and thoracic regions.

As the advance of memory technologies, multiple types of memory such as different kinds of non-volatile memory (NVM), SRAM, DRAM, etc. provide a flexible configuration considering performance, energy and cost. For improving the performance of systems with multiple types of memory, data allocation is one of the most important tasks. The previous studies on data allocation problem assume the worst (fixed) case of data-access frequencies. However, the data allocation produced by employing worst case usually leads to an inferior performance for most of time. In this paper, we model this problem by probabilities and design efficient algorithms that can give optimal-cost data allocation with a guaranteed probability. The proposed DAGP algorithm produces a set of feasible data allocation solutions which generates the minimum access time or cost guaranteed by a given probability. The experiments show that our technique can significantly reduce the access time or cost compared with the technique considering worst case scenario. For example, comparing with the optimal result generated by employing the worst cases, our technique can reduce memory access time by 10.35% on average when guaranteed probability is set to be 0.8. Moreover, for 80 percents of cases, memory access time is reduced by 23.98% on average.

To dynamically quantify pancreatic perfusion and flow within the arteries supplying the pancreas in response to secretin stimulation. Twelve healthy male subjects were scanned at 1.5T with arterial spin labeling to measure tissue perfusion and phase contrast magnetic resonance imaging (MRI) to measure vessel flow. Superior mesenteric (SMA), gastroduodenal (GDA), common hepatic (HA), and splenic (SA) arterial flow and pancreatic perfusion were serially measured for 50 minutes following 1 IU/kg intravenous secretin. The significance of differences between timepoints was tested using a repeated measures one-way analysis of variance (ANOVA). Baseline blood flow (mean ± SEM or median [IQR]) for SMA, HA, SA, and GDA was 7.6 ± 1.3, 4.0 ± 0.5, 8.2 ± 0.8, and 0.9 (0.8-1.4) ml/s, respectively. Baseline pancreatic perfusion was 200 ± 25 ml/100g/min. Blood flow increased in the SMA (234%, P < 0.0001) and GDA (155%, P = 0.015) immediately after secretin injection. Reduced HA blood flow was observed after 10 minutes (P = 0.066) with no change in SA flow (P = 0.533). Increased pancreatic perfusion was maintained for 40 minutes after injection with a maximal increase at 5 minutes (16.8%, P = 0.025). Intravenous secretin resulted in significant temporal changes in pancreatic perfusion and arterial blood flow.

Incorporating adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitors abemaciclib and ribociclib along with endocrine therapy has been shown to improve invasive disease-free survival (iDFS) for hormone receptor-positive (HR+) human epidermal receptor 2-negative (HER2-) early breast cancer (EBC). This study assesses the cost-effectiveness of this strategy, along with adjuvant aromatase inhibitors from an Indian perspective. A Markov chain model evaluated the cost-effectiveness of abemaciclib and ribociclib with letrozole compared with letrozole alone for HR+/HER2- EBC from a payer perspective in India. Key measures included lifetime quality-adjusted life-years (QALY), life-years (LY), and total costs. This study explores two scenarios for effectiveness: a best-case (BC) scenario, where the benefit of CDK4/6 inhibitors in improving iDFS lasts a lifetime, and a worst-case (WC) scenario, where benefits disappear after 5 years. Probabilistic sensitivity analyses (PSA) were used to account for simulation uncertainty. In the BC scenario, abemaciclib added 2.17 QALY and 4.96 LY, incurring ₹2,317,957.7 ($27,756.65 in US dollars [USD]) in additional costs. However, the incremental cost-effectiveness ratio (ICER) for abemaciclib exceeded India's willingness-to-pay threshold in the BC and WC scenarios. In the BC scenario, ribociclib added 0.98 QALY and 2.58 LY with added costs of ₹1,711,504.32 ($20,494.6 USD). The ICER for ribociclib also surpassed India's threshold in both scenarios. PSA showed that neither drug was cost-effective at the current market prices in either BC/WC scenario. The cost of abemaciclib and ribociclib needs to be reduced by at least 78.61% and 87.19%, respectively, to be cost-effective in the BC scenario. The combination of adjuvant abemaciclib or ribociclib with letrozole is not cost-effective for HR+/HER2- EBC in India in either the BC or WC scenario.

This paper investigates trends of historical and projected future South African coal-fired power station criteria (total primary Particulate Matter (PM), Sulphur Dioxide (SO2) and Nitrogen Oxides (NOx)) and Carbon Dioxide (CO2) emissions. It was found that an energy restricted environment has an increasing effect on emissions, as emissions per energy unit increased from the onset of the South African energy crisis. PM emissions particularly, increased during the energy crisis period, due to increased pressure on PM abatement and lowered maintenance opportunity. Projections of future coal-fired power station criteria and CO2 emissions are made for four different future scenarios for the period 2015 to 2030. Three of the four scenarios are based on the lower projected energy demand baseline case as published in the updated Integrated Development Plan (IRP). The difference between these three scenarios is different retrofit rates of power stations with emissions abatement technologies. The fourth scenario is a worst case scenario and assumes high energy demand (and therefore no decommissioning of power stations), high emission rates (similar to worst past emission rates during the period 1999-2012) and no further abatement of emissions above and beyond current mitigation efforts. This scenario gives an indication of what South African coal-fired power station emissions could look like if the energy crisis persists. There is a marked difference between projected best and worst case PM emissions during the entire projected period, but especially during 2030 when worst case PM emissions compared to a 2015 baseline value are expected to rise by 40% and best case PM emissions are projected to decline by 40%. Worst case NOx emissions are expected to increase by 40% in 2030 from a 2015 baseline value whereas best case emissions are expected to decline 10% from the same level in 2030. Worst case SO2 emissions are predicted to increase by around 38% in 2030 and best case emissions are expected to decrease by around 20% in 2030 from a 2015 baseline value. Relative emissions used in the projection of future CO2 emissions in this paper differ from that used in the energy demand and energy mix modelling done for the updated IRP baseline case. The reason for this is that the modelling for the updated IRP assumed relative CO2 emission factors for supercritical boilers, whereas only Kusile and Medupi fall in this category and relative emissions from all other stations are, in fact, between 5% and 16% higher. For this reason, it seems unlikely that the South African climate commitment target for 2030 will be made.

Analysis of Worst Case Stochastic Link Capacity Degradation to Aid Assessment of Transportation Network Reliability

Background: The autonomic nervous system is the main determinant of the blood flow directed towards a body part, and it is tightly connected to the representation of the body in the brain; would the experimental modulation of the sense of ownership of the limb affect its blood perfusion? Methods: In healthy participants, we employed the rubber hand illusion paradigm to modulate limb ownership while we monitored the brachial artery blood flow and resistance of the investigated limb. Results: In all conditions with brush-stroking, we found an initial drop in the blood flow due to tactile stimulation. Subsequently, in the illusion condition where both the rubber and real hand experience synchronous brush-stroking, the blood flow rose significantly faster and reached significantly higher values. Moreover, the increase in blood flow correlated to the embodiment level measured by questionnaires and, negatively, to the change of peripherical vascular resistance. Conclusions: These findings demonstrate that modulating the representation of a body part impacts its blood perfusion.

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Purpose: To determine the effect of vibrating rollers on skin blood flow after running for recovery from muscle fatigue. Method: 23 healthy runners, aged between 20 to 45 years, participated in a crossover trial. Muscle fatigue was induced by running, and recovery using a vibrating roller was determined before and after the intervention. Each subject was measured at three time points (prerun, postrun, and postroller) to compare skin blood flow perfusion and blood flow oscillation at the midpoint of the dominant gastrocnemius muscle. The results show that blood perfusion is greater when a vibrating roller is used than a foam roller, but there is no statistical difference. The analysis of blood flow oscillation shows that vibrating rollers induce 30% greater endothelial activation than a foam roller. Vibrating rollers significantly stimulate the characteristic frequency for myogenic activation (p < 0.05); however, the effect size is conservative.

A Comparison of Changes in Rhythms of Sacral Skin Blood Flow in Response to Heating and Indentation

OPINION article Front. Pharmacol., 25 October 2012Sec. Experimental Pharmacology and Drug Discovery Volume 3 - 2012 | https://doi.org/10.3389/fphar.2012.00187