1,618 research outputs found
The consistency in macronutrient oxidation and the role for epinephrine in the response to fasting and overfeeding
No full textCONTEXT In humans, dietary versus intra-individual determinants of macronutrient oxidation preference and the role of the sympathetic nervous system (SNS) during short-term overfeeding and fasting are unclear.
OBJECTIVE To understand the influence of diet and the SNS during 24-h of overfeeding on metabolic changes.
DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS While residing on a clinical research unit, 64 participants with normal glucose regulation were assessed during energy balance, fasting, and four 24-h overfeeding diets, given in random order. The overfeeding diets contained 200% of energy requirements and varied macronutrient proportions: 1) standard (50% carbohydrate, 20% protein, and 30% fat), 2) 75% carbohydrate, 3) 60% fat, and 4) 3% protein.
MAIN OUTCOME MEASURES 24-hour energy expenditure (EE) and macronutrient oxidation rates were measured in an indirect calorimeter during the dietary interventions, with concomitant measurement of urinary catecholamines and free cortisol.
RESULTS EE decreased with fasting (-7.7±4.8%, p<0.0001) and increased with overfeeding. The smallest increase occurred during the diet with 3% protein (2.7±4.5%, p=0.001) and the greatest during the diet with 75% carbohydrate (13.8±5.7%, p<0.0001). Approximately 60% of macronutrient oxidation was determined by diet and 20% by intrinsic factors (p<0.0001). Only urinary epinephrine differed between fasting and overfeeding diets (Δ=2.25±2.9 µg/24h, p<0.0001). During fasting, higher urinary epinephrine concentrations correlated with smaller reductions in EE (ρ=0.34, p=0.01).
CONCLUSIONS Independent from dietary macronutrient proportions, there is a strong individual contribution to fuel preference that remains consistent across diets. Higher urinary epinephrine may reflect the importance of epinephrine in maintaining EE during fasting
Energy Expenditure and Hormone Responses in Humans After Overeating High-Fructose Corn Syrup versus Whole-Wheat Foods
No full textOBJECTIVE: This study sought to understand how the dietary source of carbohydrates, either high-fructose corn syrup (HFCS) or complex carbohydrates, affects energy expenditure (EE) measures, appetitive sensations, and hormones during 24 hours of overfeeding. METHODS: Seventeen healthy participants with normal glucose regulation had 24-hour EE measures and fasting blood and 24-hour urine collection during four different 1-day diets, including an energy-balanced diet, fasting, and two 75% carbohydrate diets (5% fat) given at 200% of energy requirements with either HFCS or whole-wheat foods as the carbohydrate source. In eight volunteers, hunger was assessed with visual analog scales the morning after the diets. RESULTS: Compared with energy balance, 24-hour EE increased 12.8% +/- 6.9% with carbohydrate overfeeding (P < 0.0001). No differences in 24-hour EE or macronutrient utilization were observed between the two high-carbohydrate diets; however, sleeping metabolic rate was higher after the HFCS diet (Delta = 35 +/- 48 kcal [146 +/- 200 kJ]; P = 0.01). Insulin, ghrelin, and triglycerides increased the morning after both overfeeding diets. Urinary cortisol concentrations (82.8 +/- 35.9 vs. 107.6 +/- 46.9 nmol/24 h; P = 0.01) and morning-after hunger scores (Delta = 2.4 +/- 2.0 cm; P = 0.01) were higher with HFCS overfeeding. CONCLUSIONS: The dietary carbohydrate source while overeating did not affect 24-hour EE, but HFCS overconsumption may predispose individuals to further overeating due to increased glucocorticoid release and increased hunger the following morning
Specific skeletal muscle sphingolipid compounds in energy expenditure regulation and weight gain in native Americans of Southwestern heritage
No full textBACKGROUND/OBJECTIVES: In animal models, a role in the regulation of energy expenditure (EE) has been ascribed to sphingolipids, active components of cell membranes participating in cellular signaling. In humans, it is unknown whether sphingolipids have a role in the modulation of EE and, consequently, influence weight gain. The present study investigated the putative association of EE and weight gain with sphingolipid levels in the human skeletal muscle, a component of fat-free mass (the strongest determinant of EE), in adipose tissue and plasma.
SUBJECTS/METHODS: Twenty-four-hour EE, sleeping metabolic rate (SMR) and resting metabolic rate (RMR) were assessed in 35 healthy Native Americans of Southwestern heritage (24 male; 30.2 +/- 7.73 years). Sphingolipid (ceramide, C; sphingomyelin, SM) concentrations were measured in skeletal muscle tissue, subcutaneous adipose tissue and plasma samples. After 6.68 years (0.2612.4 years), follow-up weights were determined in 16 participants (4 females).
RESULTS: Concentrations of C24: 0, SM18: 1/26: 1 and SM18: 0/24: 1 in muscle were associated with 24-h EE (r = -0.47, P = 0.01), SMR (r = -0.59, P = 0.0008) and RMR (r = -0.44, P = 0.01), respectively. Certain muscle sphingomyelins also predicted weight gain (for example, SM18: 1/23: 1, r = 0.74, P = 0.004). For specific muscle sphingomyelins that correlated with weight gain and EE (SM18: 1/23: 0, SM18: 1/23: 1 and SMR, r = -0.51, r = -0.41, respectively, all P<0.03; SM18: 1/24: 2 and RMR, r = -0.36, P = 0.03), associations could be reproduced with SMR in adipose tissue (all r < -0.46, all P < 0.04), though not in plasma.
CONCLUSIONS: This study provides preliminary, novel evidence, that specific muscle and adipose tissue sphingolipid compounds are associated with EE and weight gain in Native Americans of Southwestern heritage. Further studies are warranted to investigate whether sphingolipids of different body compartments act in concert to modulate energy balance in humans
Norepinephrine and thyroxine are predictors of fat mass gain in humans with cold-induced brown adipose tissue activation
No full textContext: In healthy adults with detectable cold-induced brown adipose tissue activation (CIBA), the relationships between sympathetic nervous system (SNS) or thyroid activity during energy balance (EBL) with CIBA and body composition change are undetermined.
Objective: To investigate the relationships between CIBA and thermoneutral catecholamines and thyroid hormones measured during EBL and to determine if CIBA, catecholamines, or thyroid hormones predict body composition changes.
Design, Setting, Participants, and Interventions: Twelve healthy volunteers (seven male and five female) with positive CIBA [>2 standardized uptake value (g/mL)] had 24-hour energy expenditure (24hEE) assessed during EBL via whole-room indirect calorimetry while residing on a clinical research unit. Positron emission tomography/computed tomography scans were performed after exposure to 16 degrees C for 2 hours to quantify CIBA.
Main Outcome Measures: CIBA, 24hEE during EBL, and thermoneutrality with concomitant measurement of urinary catecholamines and plasma free T3 and free T4. Body composition at baseline and 6 months by dual-energy X-ray absorptiometry.
Results: Lower urinary norepinephrine and free T4 were associated with higher CIBA (r = -0.65, P = 0.03; and r = -0.75, P < 0.01, respectively), but CIBA was not associated with 24hEE at thermoneutrality (P = 0.77). Lower CIBA (beta = -3.5 kg/standardized uptake value; P < 0.01) predicted fat mass gain, whereas higher urinary norepinephrine and free T4 predicted future fat mass gain at 6 months (beta = 3.0 kg per twofold difference in norepinephrine, P = 0.03; and beta = 1.2 kg per 0.1-ng/dL difference in free T4, P = 0.03, respectively).
Conclusion: Lower SNS and free thyroid measurements at baseline indicate a greater capacity for CIBA, which may be predictive against fat mass gain
Usefulness of quantifying serum KL-6 levels in the follow-up of uveitic patients with sarcoidosis
No full textBackground: KL-6 is a human glycoprotein secreted by type II alveolar cells in the lung, and its serum levels increase in pneumonia of various causes. We previously reported that serum KL-6 levels in uveitis patients with sarcoidosis were significantly higher than those of other uveitis patients and healthy controls. Additionally, the combined measurement of serum KL-6 and angiotensin converting enzyme (ACE) was useful for screening uveitic patients to diagnose sarcoidosis. The purpose of the present study was to investigate the clinical usefulness of quantifying serum KL-6 levels for following-up the patients with sarcoidosis. Methods: Sera were obtained from 36 uveitic patients diagnosed with sarcoidosis and the same number of healthy volunteers. To examine the influence of systemic medication, we also collected blood samples from four more sarcoidosis patients, who were systemically treated with corticosteroid or angiotensin converting enzyme (ACE) inhibitor, an anti-hypertensive drug. The serum concentration of KL-6 was measured by a human KL-6 electrochemiluminescence immunoassay (ECLIA). Results: The mean KL-6 concentrations of sarcoidosis patients and healthy controls were 449.3 +/- 66.3 (mean +/- SE) and 192.1 +/- 11.3, respectively. The average levels of serum KL-6 were significantly elevated in sarcoidosis patients compared with healthy control subjects (P < 0.001), and there were significant correlations between serum KL-6 and ACE levels in the patients with sarcoidosis (r=0.70 and P < 0.0001). Moreover, serum KL-6 concentrations were less affected by systemic corticosteroid, and unaffected by ACE inhibitory drugs in contrast to ACE levels. Conclusions: Measurement of serum KL-6 in the uveitic patients may be useful to follow-up the diagnosed sarcoidosis, as well as for diagnosing sarcoidosis, because the serum KL-6 level was well correlated with the ACE level, and less affected by systemic medication than ACE levels
Serial KL-6 measurements in COVID-19 patients
No full textSARS-CoV2-induced direct cytopathic effects against type II pneumocytes are suspected to play a role in mediating and perpetuating lung damage. The aim of this study was to evaluate serum KL-6 behavior in COVID-19 patients to investigate its potential role in predicting clinical course. Sixty patients (median age IQR, 65 (52–69), 43 males), hospitalized for COVID-19 at Siena COVID Unit University Hospital, were prospectively enrolled. Twenty-six patients were selected (median age IQR, 63 (55–71), 16 males); all of them underwent follow-up evaluations, including clinical, radiological, functional, and serum KL-6 assessments, after 6 (t1) and 9 (t2) months from hospital discharge. At t0, KL-6 concentrations were significantly higher than those at t1 (760 (311–1218) vs. 309 (210–408) p = 0.0208) and t2 (760 (311–1218) vs 324 (279–458), p = 0.0365). At t0, KL-6 concentrations were increased in patients with fibrotic lung alterations than in non-fibrotic group (755 (370–1023) vs. 305 (225–608), p = 0.0225). Area under the receiver operating curve (AUROC) analysis showed that basal KL-6 levels showed good accuracy in discriminating patients with fibrotic sequelae radiologically documented (AUC 85%, p = 0.0404). KL-6 concentrations in patients with fibrotic involvement were significantly reduced at t1 (755 (370–1023) vs. 290 (197–521), p = 0.0366) and t2 (755 (370–1023) vs. 318 (173–435), p = 0.0490). Serum concentrations of KL-6 in hospitalized COVID-19 patients may contribute to identify severe patients requiring mechanical ventilation and to predict those who will develop pulmonary fibrotic sequelae in the follow-up. © 2021, The Author(s)
A smooth Lyapunov function from a class-KL estimate involving two positive semidefinite functions
No full textWe consider differential inclusions where a positive semidefinite function of the solutions satisfies a class-KL estimate in terms of time and a second positive semidefinite function of the initial condition. We show that a smooth converse Lyapunov function, i.e., one whose derivative along solutions can be used to establish the class-KL estimate, exists if and only if the class-KL estimate is robust, i.e., it holds for a larger, perturbed differential inclusion. It remains an open question whether all class-KL estimates are robust. One sufficient condition for robustness is that the original differential inclusion is locally Lipschitz. Another sufficient condition is that the two positive semidefinite functions agree and a backward completability condition holds. These special cases unify and generalize many results on converse Lyapunov theorems for differential equations and differential inclusions that have appeared in the literature. Corresponding author. y Research supported i..
KL Process Design Group: unleashing natural sugars for tomorrow's strategic energy plan
No full textPresented at the Can forests meet our energy needs? The future of forest biomass in Colorado conference, February 21, 2008, Colorado State University, Fort Collins, Colorado.James Schultze is a process engineer with KL Process Design Group in Rapid City, South Dakota. He has been working on KL's biomass project since 2006 and has been involved in the research, construction and operation of the newly constructed biomass plant in Upton, WY. His industry experience started with Shell Oil Company in Houston, TX as a production engineer in Shell's Midcontinent Division. Jim is a chemical engineering graduate of the South Dakota School of Mines and Technology in Rapid City, SD
Aircraft component health analysis for predictive maintenance: using a dilated convolutional autoencoder and KL divergence
No full textThe detection of anomalous behaviour is fundamental to component health analysis techniques. However, detecting anomalies is a difficult and time consuming task if their form, location, and frequency are unknown. This research introduces an innovative unsupervised predictive maintenance pipeline that requires minimal domain knowledge and time to create competitive and insightful health monitoring models. First, a Dilated Convolutional Autoencoder learns to recreate healthy sensor data. Then, a Kullback-Leibler (KL) divergence based health analysis transforms discrepancies between the reconstruction and the sensor data into a single performance metric per sensor per flight. A novel evaluation method based on the KL divergence metric allows for quantitative evaluation and hyperparameter tuning of the autoencoder. Results provide new insights and show competitive performance on analysing the fuel level measuring system. Additionally, in a generalisability study on the braking system of a different aircraft type the proposed method outperforms the currently employed health monitoring model in precision and F1 score. The main advantages of the proposed method are; the ability to rapidly create unbiased health indicators on a sensor level, the capability to generalise to other components, and a framework to quantitatively evaluate the model’s performance when no truth labels are available.Mechanical Engineering | Vehicle Engineering | Cognitive Robotic
BIMA ARRAY 3 MM SPECTRAL LINE SURVEY OF ORION-KL
No full textAuthor Institution: University of Illinois, Dept. of Astronomy, 1002 W. Green St, Urbana, IL 61801; National Radio Astronomy Observatory, Charlottesville, VA 22903; NASA Goddard Space Flight Center, Space and Earth Data Computing Division, Code 930, Greenbelt, MD 20771; National Research Council Resident Research AssociateWith the Berkeley-Illinois-Maryland-Association (BIMA) Array we have carried out a 3 mm (80-115.9 GHz) spectral line survey of Orion-KL. Orion-KL is composed of several distinct regions separated by only a few arcseconds, most notably the ``Hot Core'', where N bearing species are most prevalent, and the ``Compact Ridge'', where O bearing species are most prevalent. For our observations the average synthesized beam was 14''x8''. We detected over 700 spectral features from the ``Hot Core'' and over 600 spectral features from the ``Compact Ridge''. We will present the abundances and spatial distribution of the detected species
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