263 research outputs found
A type-2 fuzzy modelling framework for aircraft taxi-time prediction
Knowing aircraft taxi-time precisely a-priori is increasingly important for any airport management system. This work presents a new approach for estimating and characterising the taxi-time of an aircraft based on historical information. The approach makes use of the interval type-2 fuzzy logic system, which provides more robustness and accuracy than the conventional type-1 fuzzy system. To compensate for erroneous modelling assumptions, the error distribution of the model is further analysed and an error compensation strategy is developed. Results, when tested on a real data set for Manchester Airport (U.K.), show improved taxi-time accuracy and generalisation capability over a wide range of modelling assumptions when compared with existing fuzzy systems and linear regression-based methods
Dynamic glucose disposal is driven by reduced endogenous glucose production in response to voluntary wheel running: A stable isotope approach
Ā© 2020 the American Physiological Society. Dynamic glucose disposal is driven by reduced endogenous glucose production in response to voluntary wheel running: A stable isotope approach. Am J Physiol Endocrinol Metab 319: E2-E10, 2020. First published April 28, 2020; doi:10.1152/ajpendo.00450.2019.-To resolve both the systems level and molecular mechanisms responsible for exerciseinduced improvements in glucose tolerance, we sought to test the effect of voluntary wheel running exercise on postprandial glucose dynamics. We utilized a stable isotope-labeled oral glucose tolerance test (SI-OGTT) incorporating complementary deuterium glucose tracers at a 1:1 ratio (2-2H-glucose and 6-6 2H-glucose; 2g/kg lean body mass) to distinguish between endogenous glucose production (EGP) and whole-body glucose disposal. SI-OGTT was performed in C57BL/6J mice after 8 wk on a high-fat diet (HFD; 45% fat). Mice were then randomized to either a wheel-running cage (n = 13, HFD Ex) or a normal cage (n = 13, HFD Sed) while maintaining the HFD for 4 wk before performing a SI-OGTT. HFD Ex mice demonstrated improvements in whole blood glucose total area under the curve (AUC) that was attributed primarily to a reduction in EGP AUC. Serum insulin levels measured at 0 and 15 min post-glucose gavage were significantly elevated in the HFD Sed mice, whereas HFD Ex mice demonstrated the expected reduction in insulin at both time points. Overall, exercise improved hepatic insulin sensitivity by reducing postprandial EGP, but also increased whole-body glucose disposal. Finally, these results demonstrate the benefits of exercise on hepatic insulin sensitivity by combining a more physiological route of glucose administration (oral glucose) with the resolution of stable isotope tracers. These novel observations clearly demonstrate that SI-OGTT is a sensitive and cost-effective method to measure exercise adaptations in obese mice with as little as 2 Ī¼l of tail blood
Serological markers of gluten sensitivity in Border terriers with gall bladder mucocoeles
Objectives
To evaluate serological markers of gluten sensitivity in conjunction with cholecystokinin measurement in Border terriers with gall bladder mucocoeles.
Materials and Methods
Medical records from two referral hospitals were obtained between 2011 and 2019 to identify Border terriers with gall bladder mucocoeles, nonāBorder terriers with gall bladder mucocoeles and control Border terriers with nonābiliary diseases. Enzymeālinked immunosorbent assays were performed on stored fasted serum samples for antiāgliadin IgG, antiācanine transglutaminaseā2āIgA autoantibodies and cholecystokinin. Statistical analysis was performed using the KruskallāWallis test to identify differences between the groups.
Results
Fifteen Border terriers with gall bladder mucocoeles, 17 nonāBorder terriers with gall bladder mucocoeles and 14 control Border terriers with nonābiliary diseases were recruited. Median transglutaminaseā2āIgA autoantibodies in Border terriers with gall bladder mucocoeles was 0.73 (range: 0.18 to 1.67), which was significantly greater than in control Border terriers at 0.41 (0.07 to 1.14). Median cholecystokinin concentration in Border terriers with gall bladder mucocoeles was 13āpg/mL (6 to 45 pg/mL), which was significantly lower than in control Border terriers at 103āpg/mL (9 to 397 pg/mL). There was no difference in the antiāgliadin IgG between these groups. There was no difference observed in the nonāBorder terriers with gall bladder mucocoeles with either of the other groups.
Clinical Significance
Reduced cholecystokinin and increased transglutaminaseā2āIgA autoantibodies was detected in Border terriers with gall bladder mucocoeles; which is in part homologous to gall bladder disease identified in human coeliac disease. The results suggest an immunological disease with impaired cholecystokinin release may be affecting gall bladder motility and possibly contributing to mucocoele formation in Border terriers
Muscle volume is related to trabecular and cortical bone architecture in typically developing children
Introduction: Muscle is strongly related to cortical bone architecture in children; however, the relationship between muscle volume and trabecular bone architecture is poorly studied. The aim of this study was to determine if muscle volume is related to trabecular bone architecture in children and if the relationship is different than the relationship between muscle volume and cortical bone architecture. Materials and methods: Forty typically developing children (20 boys and 20 girls; 6 to 12. y) were included in the study. Measures of trabecular bone architecture [i.e., apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th) and trabecular separation (appTb.Sp)] in the distal femur, cortical bone architecture [cortical volume, total volume, section modulus (Z) and polar moment of inertia (J)] in the midfemur, muscle volume in the midthigh and femur length were assessed using magnetic resonance imaging. Total physical activity and moderate-to-vigorous physical activity were assessed using an accelerometer-based activity monitor worn around the waist for four days. Calcium intake was assessed using diet records. Relationships among the measures were tested using multiple linear regression analysis. Results: Muscle volume was moderately-to-strongly related to measures of trabecular bone architecture [appBV/TV (r=0.81), appTb.N (r=0.53), appTb.Th (r=0.67), appTb.Sp (r=-0.71); all p0.05). Because muscle volume and femur length were strongly related (r=0.91, p2.77). When muscle volume/femur length2.77 was included in a regression model with femur length, sex, physical activity and calcium intake, muscle volume/femur length2.77 was a significant predictor of appBV/TV, appTb.Th and appTb.Sp (partial r=0.44 to 0.49, p<0.05) and all measures of cortical bone architecture (partial r=0.47 to 0.54; p<0.01). Conclusions: The findings suggest that muscle volume in the midthigh is related to trabecular bone architecture in the distal femur of typically developing children. The relationship is weaker than the relationship between muscle volume in the midthigh and cortical bone architecture in the midfemur, but the discrepancy is driven, in large part, by the greater dependence of cortical bone architecture measures on femur length
0111i I ll III ACTUATOR PLACEMENT FOR ACTIVE SURGE CONTROL IN A MULTI-STAGE AXIAL COMPRESSOR
ABSTRACT. This paper describes an actuator placement methodology for the active control of purely onedimensional instabilities of a seven-stage axial compressor using an air bleeding strategy. In this theoretical study, using stage-by-stage non-linear modelling based on the conservation equations of mass, momentum, and energy, a scheduling LQR (Linear Quadratic Regulator) controller is designed for several actuator locations in a compressor from the first stage to the plenum. In this controller design, the LQR weighting matrices are selected so that the associated cost function includes only air bleeding mass flow leading to the minimisation of the air bleed. The LQR cost function represents a measure of the consumption of air bleeding and can be calculated analytically using the solution of an Algebraic Riccati Equation. From analysis of the cost at different compressor stages, the location of an air bleeding actuator is selected at the stage with the minimum cost. Finally, using an ACSL simulation program, the scheduling controller has been integrated with a non-lineat stage-by-stage model and the time response of the air bleeding mass flow at different locations has been obtained to confirm the results from the analytical approach. Results are presented to show actively stabilised compressor flow beyond the surge point where the air bleed is minimised. These results also indicate the preferred location of the actuator at the compressor downstream stages for both low and high compressor speeds
Co-ingestion of whey protein with a carbohydrate-rich breakfast boes not affect glycemia, insulinemia or subjective appetite following a subsequent meal in healthy males
We aimed to assess postprandial metabolic and appetite responses to a mixed-macronutrient lunch following prior addition of whey protein to a carbohydrate-rich breakfast. Ten healthy males (age: 24 Ā± 1 y; body mass index (BMI): 24.5 Ā± 0.7 kg/m2) completed three trials in a non-isocaloric, crossover design. A carbohydrate-rich breakfast (93 g carbohydrate; 1799 kJ) was consumed with (CHO+WP) or without (CHO) 20 g whey protein isolate (373 kJ), or breakfast was omitted (NB). At 180 minutes, participants consumed a mixed-macronutrient lunch meal. Venous blood was sampled at 15 minute intervals following each meal and every 30 minutes thereafter, while subjective appetite sensations were collected every 30 minutes throughout. Post-breakfast insulinaemia was greater after CHO+WP (time-averaged area under the curve (AUC0-180 min): 193.1 Ā± 26.3 pmol/L), compared to CHO (154.7 Ā± 18.5 pmol/L) and NB (46.1 Ā± 8.0 pmol/L; p < 0.05), with no difference in post breakfast (0-180 min) glycaemia (CHO+WP, 3.8 Ā± 0.2 mmol/L; CHO, 4.2 Ā± 0.2 mmol/L; NB, 4.2 Ā± 0.1 mmol/L; p = 0.247). There were no post lunch (0-180 min) effects of condition on glycaemia (p = 0.492), insulinaemia (p = 0.338) or subjective appetite (p > 0.05). Adding whey protein to a carbohydrate-rich breakfast enhanced the acute postprandial insulin response, without influencing metabolic or appetite responses following a subsequent mixed-macronutrient meal
The effects of collagen peptides on muscle damage, inflammation and bone turnover following exercise:a randomized, controlled trial
This study examined whether consuming collagen peptides (CP) before and after strenuous exercise alters markers of muscle damage, inflammation and bone turnover. Using a double-blind, independent groupās design, 24 recreationally active males consumed either 20 g dayā1 of CP or a placebo control (CON) for 7 days before and 2 days after performing 150 drop jumps. Maximal isometric voluntary contractions, countermovement jumps (CMJ), muscle soreness (200 mm visual analogue scale), pressure pain threshold, Brief Assessment of Mood Adapted (BAM +) and a range of blood markers associated with muscle damage, inflammation and bone turnover C-terminal telopeptide of type 1 collagen (Ī²-CTX) and N-terminal propeptides of type 1 pro-collagen (P1NP) were measured before supplementation (baseline; BL), pre, post, 1.5, 24 and 48 h post-exercise. Muscle soreness was not significantly different in CP and CON (P = 0.071) but a large effect size was evident at 48 h postexercise, indicative of lower soreness in the CP group (90.42 Ā± 45.33 mm vs. CON 125.67 Ā± 36.50 mm; ES = 2.64). CMJ height recovered quicker with CP than CON at 48 h (P = 0.050; CP 89.96 Ā± 12.85 vs. CON 78.67 Ā± 14.41% of baseline values; ES = 0.55). There were no statistically significant effects for the other dependent variables (P > 0.05). Ī²-CTX and P1NP were unaffected by CP supplementation (P > 0.05). In conclusion, CP had moderate benefits for the recovery of CMJ and muscle soreness but had no influence on inflammation and bone collagen synthesis
Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery
This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle
damage following a marathon. Using a double blind, independent groupās design, 34 runners
(~16 previous marathons completed) consumed either BTJ or an isocaloric placebo (PLA) for
3 days following a marathon. Maximal isometric voluntary contractions (MIVC),
countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine
kinase (CK), high sensitivity C-reactive protein (hs-CRP) and aspartate aminotransferase
(AST) were measured pre, post, and on the 2 days after the marathon. CMJ and MIVC were
reduced after the marathon (P0.05).
Muscle soreness was increased in the day after the marathon (BTJ; 45Ā±48 vs. PLA; 46Ā±39
mm) and had returned to baseline by day 2, irrespective of supplementation (P=0.694).
Cytokines (Interleukin-6; IL-6, interleukin-8, tumour necrosis factor-Ī±) were increased
immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post.
No interaction effects were evident for IL-6 (P=0.213). Leucocytes increased 1.7 fold after
the race and remained elevated 2 days post, irrespective of supplement (P<0.0001). CK
peaked at 1 day post marathon (BTJ: 965Ā±967 & PLA: 1141Ā±979 IUĀ·L-1) and like AST and
hs-CRP, was still elevated 2 days after the marathon (P<0.05); however, no group differences
were present for these variables. Beetroot juice did not attenuate inflammation or reduce
muscle damage following a marathon, possibly because most of these indices were not
markedly different from baseline values in the days after the marathon
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