scholarly journals Guiding Ketogenic Diet with Breath Acetone Sensors

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3655 ◽  
Author(s):  
Andreas T. Güntner ◽  
Julia F. Kompalla ◽  
Henning Landis ◽  
S. Theodore ◽  
Bettina Geidl ◽  
...  
Keyword(s):  
Ketogenic Diet ◽  
Standard Treatment ◽  
Refractory Epilepsy ◽  
Neurological Diseases ◽  
Endurance Performance ◽  
Response Characteristics ◽  
Si Doped ◽  
Breath Acetone ◽  
Relevant Range ◽  
Good Agreement

Ketogenic diet (KD; high fat, low carb) is a standard treatment for obesity, neurological diseases (e.g., refractory epilepsy) and a promising method for athletes to improve their endurance performance. Therein, the level of ketosis must be regulated tightly to ensure an effective therapy. Here, we introduce a compact and inexpensive breath sensor to monitor ketosis online and non-invasively. The sensor consists of Si-doped WO3 nanoparticles that detect breath acetone selectively with non-linear response characteristics in the relevant range of 1 to 66 ppm, as identified by mass spectrometry. When tested on eleven subjects (five women and six men) undergoing a 36-h KD based on the Johns Hopkins protocol, this sensor clearly recognizes the onset and progression of ketosis. This is in good agreement to capillary blood β-hydroxybutyrate (BOHB) measurements. Despite similar dieting conditions, strong inter-subject differences in ketosis dynamics were observed and correctly identified by the sensor. These even included breath acetone patterns that could be linked to low tolerance to that diet. As a result, this portable breath sensor represents an easily applicable and reliable technology to monitor KD, possibly during medical treatment of epilepsy and weight loss.

scholarly journals The modified ketogenic diet for adults with refractory epilepsy: An evaluation of a set up service

Seizure ◽  
2017 ◽  
Vol 52 ◽  
pp. 1-6 ◽  
Author(s):  
Kirsty J. Martin-McGill ◽  
Michael D. Jenkinson ◽  
Catrin Tudur Smith ◽  
Anthony G. Marson
Keyword(s):  
Ketogenic Diet ◽  
Refractory Epilepsy ◽  
Set Up ◽  
Modified Ketogenic Diet

Theoretical Prediction of Motions of High-Speed Planing Boats in Waves

1978 ◽  
Vol 22 (03) ◽  
pp. 140-169
Author(s):  
Milton Martin
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Nonlinear Effects ◽  
Theoretical Method ◽  
Valuable Insight ◽  
Response Characteristics ◽  
Theoretical Predictions ◽  
Response Amplitude Operators ◽  
Phase Angles ◽  
Good Agreement

A theoretical method is derived for predicting the linearized response characteristics of constant deadrise high-speed planing boats in head and following waves. Comparisons of the theoretical predictions of the pitch and heave response amplitude operators and phase angles with existing experimental data show reasonably good agreement for a wide variety of conditions of interest. It appears that nonlinear effects are more severe at a speed to length ratio of 6 than of, say, 4 or less, principally because of the reduction of the damping ratio of the boat with increasing speed, and the consequent increase in motions in the vicinity of the resonant encounter frequency. However, it is concluded that the linear theory can provide a simple and fast means of determining the effect of various parameters such as trim angle, deadrise, loading, and speed on the damping, natural frequency, and linearized response in waves, and that this can furnish valuable insight into the actual boat dynamics, even though the accurate predictions of large motions and peak accelerations would require a nonlinear analysis.

Thermocouple Response Characteristics in Deflagrating Low-Conductivity Materials

1971 ◽  
Vol 93 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Nam P. Suh ◽  
C. L. Tsai
Keyword(s):  
Theoretical Model ◽  
Gas Phase ◽  
Wire Diameter ◽  
Solid Propellants ◽  
Optimum Ratio ◽  
Response Characteristics ◽  
Bead Diameter ◽  
Double Base ◽  
Theoretical Results ◽  
Good Agreement

The transient thermocouple response characteristics in deflagrating low-conductivity materials with high temperature gradients were investigated theoretically and experimentally. The theoretical model considers the thermocouple bead and lead wires separately, and the two resulting partial differential equations are solved simultaneously by a finite difference technique. The experimental results are obtained by embedding various size thermocouple wires in double-base solid propellants and consequently measuring the temperature profiles and the surface temperatures. The theoretical model is used to predict the experimentally measured temperatures. There is good agreement. The experimentally measured values are smaller than the correct surface temperature, corresponding to the model prediction for zero wire diameter, by at least 20 percent even when 1/2-mil thermocouple wire is used. Both the experimental and theoretical results show a plateau when the thermocouple bead emerges from the solid into the gas phase. The theoretical results also show that there is an optimum ratio of. the thermocouple bead diameter to the wire diameter, which is found to be close to three

Autonomic and Perceptual Responses to Induction of a Ketogenic Diet in Free-Living Endurance Athletes: A Randomized, Crossover Trial

2020 ◽  
pp. 1-7
Author(s):  
Ed Maunder ◽  
Deborah K. Dulson ◽  
David M. Shaw
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Capacity ◽  
Ketogenic Diet ◽  
Physiological Stress ◽  
Endurance Performance ◽  
Endurance Athletes ◽  
Recovery Stress ◽  
Individual Level ◽  
Dietary Shift

Purpose: Considerable interindividual heterogeneity has been observed in endurance performance responses following induction of a ketogenic diet (KD). It is plausible that a physiological stress response in the period following the dramatic dietary shift associated with transition to a KD may explain this heterogeneity. Methods: In a randomized, crossover study design, 8 trained male runners completed an incremental exercise test and ran to exhaustion at 70%VO2max before and after a 31-day rigorously controlled habitual diet or KD intervention, and recorded heart rate variability (root mean square of the sum of successive differences in R–R intervals [rMSSD]) upon waking each morning along with the recovery–stress questionnaire for athletes each week. Data were analyzed using linear mixed models. Results: A significant reduction in rMSSD was observed in the KD (−9.77 [4.03] ms, P = .02), along with an increase in day-to-day variability in rMSSD (2.1% [1.0%], P = .03). The reduction in rMSSD in the KD for the subgroup of individuals exhibiting impaired exercise capacity following induction of the KD approached significance (Δ −22 [15] ms, P = .06, N = 4); whereas no effect was observed in those who exhibited unchanged exercise capacity (Δ 5 [18] ms, P = .61, N = 4). No main effects were observed for recovery–stress questionnaire for athletes. Conclusions: Our data suggest those working with endurance athletes transitioning onto a KD may consider using noninvasive, inexpensive resting heart rate variability measures to gain individual-level insights into the likely short-term effects on exercise capacity.

scholarly journals Ketogenic diet treatment as adjuvant to standard treatment of glioblastoma multiforme: a feasibility and safety study

2019 ◽  
Vol 11 ◽  
pp. 175883591985395 ◽  
Author(s):  
Elles J. T. M. van der Louw ◽  
Joanne F. Olieman ◽  
Patricia M. L. A. van den Bemt ◽  
Jacoline E. C. Bromberg ◽  
Esther Oomen-de Hoop ◽  
...  
Keyword(s):  
Overall Survival ◽  
Glioblastoma Multiforme ◽  
Ketogenic Diet ◽  
Standard Treatment ◽  
Medium Chain Triglyceride ◽  
High Grade Glioma ◽  
Future Research ◽  
Clinical Trial Registration ◽  
Beneficial Effects ◽  
Neurological Functioning

Background: High-grade glioma cells consume mainly glucose and cannot compensate for glucose restriction. Apoptosis may potentially occur under carbohydrate restriction by a ketogenic diet (KD). We explored the feasibility and safety of KD during standard treatment of chemoradiation in patients with glioblastoma multiforme. Methods: A full liquid KD induced ketosis within 2 weeks before start of chemoradiation. After 6 weeks, the KD was modified with solid foods and medium-chain-triglyceride emulsions and used for an additional 6 weeks while maintaining ketosis. During the total study period (14 weeks), feasibility, safety, coping (both patient and partner), quality of life (QoL), neurological functioning and impairment were measured. Overall survival was analyzed with actuarial estimates. Results: Eleven patients started the study protocol, nine reached ketosis and six (67%) completed the study. Severe adverse effects did not occur. The majority of coping scores ranged from 3 to 6 on a 10-point scale at all timepoints; QoL, neurological functioning, and impairment did not essentially change over time; overall survival ranged between 9.8 and 19.0 months. Conclusion: KD was feasible and safe as an adjuvant to standard chemoradiation treatment of glioblastoma multiforme. A supportive partner and intensive counseling were essential for coping. Future research should identify possible beneficial effects on overall survival. Clinical trial registration: Netherlands Trial Registry: NTR5167 (registration date 29-01-2015), http://www.trialregister.nl/trialreg/index.asp

Analytical Electromechanical Model of Cantilevered Bi-Stable Composites for Broadband Energy Harvesting

2013 ◽  
Author(s):  
Andres F. Arrieta ◽  
Tommaso Delpero ◽  
Paolo Ermanni
Keyword(s):  
Energy Harvesting ◽  
Large Amplitude ◽  
Wide Band ◽  
Electrical Energy ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Rapid Reduction ◽  
Electromechanical Model ◽  
Response Characteristics ◽  
Good Agreement

Vibration based energy harvesting has received extensive attention in the engineering community for the past decade thanks to its potential for autonomous powering small electronic devices. For this purpose, linear electromechanical devices converting mechanical to useful electrical energy have been extensively investigated. Such systems operate optimally when excited close to or at resonance, however, for these lightly damped structures small variations in the ambient vibration frequency results in a rapid reduction of performance. The idea to use nonlinearity to obtain large amplitude response in a wider frequency range, has shown the potential for achieving so called broadband energy harvesting. An interesting type of nonlinear structures exhibiting the desired broadband response characteristics are bi-stable composites. The bi-stable nature of these composites allows for designing several ranges of wide band large amplitude oscillations, from which high power can be harvested. In this paper, an analytical electromechanical model of cantilevered piezoelectric bi-stable composites for broadband harvesting is presented. The model allows to calculate the modal characteristics, such as natural frequencies and mode shapes, providing a tool for the design of bi-stable composites as harvesting devices. The generalised coupling coefficient is used to select the positioning of piezoelectric elements on the composites for maximising the conversion energy. The modal response of a test specimen is obtained and compared to theoretical results showing good agreement, thus validating the model.

scholarly journals A Prospective Study on Changes in Nutritional Status and Growth Following Two Years of Ketogenic Diet (KD) Therapy in Children with Refractory Epilepsy

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1596 ◽  
Author(s):  
Marisa Armeno ◽  
Antonella Verini ◽  
Mariana del Pino ◽  
Maria Beatriz Araujo ◽  
Graciela Mestre ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Prospective Study ◽  
Ketogenic Diet ◽  
Refractory Epilepsy ◽  
Growth Monitoring ◽  
Male Predominance ◽  
History Of ◽  
A Prospective Study ◽  
Growth Deceleration

Introduction: Epilepsy is a neurological disorder characterized by an increased susceptibility to seizures. The ketogenic diet (KD) is currently the most important alternative non-pharmacological treatment. Despite its long history of clinical use, it is not clear how this diet affects longitudinal growth in children. Methods: A prospective study was designed to evaluate growth and nutritional status in 45 children on KD. Growth was assessed by measuring weight, height, and body mass index (BMI). Standard deviation scores (SDS) were calculated for all measurement parameters at KD initiation and at a two-year follow-up. Results: Overall, 45 patients who completed 24 months on KD were enrolled. Median age was 6.6 years (0.8 to 17.3), with a male predominance (n = 23); 74% of the 45 patients were responders on seizure reduction at three months; 26% of patients were non-responders. In our study, using −1 SDS as a cut-off point, growth deceleration was observed in 9% (n: 4) of the patients; however, the nutritional status was maintained or even improved. No correlation with age, sex, or ambulatory status was found. Conclusions: The nutritional follow-up of these patients was helpful to improve overweight and thinness but could not avoid growth deceleration in some of them. These findings confirm that children with refractory epilepsy on KD treatment require careful growth monitoring.

scholarly journals The ketogenic diet is effective for refractory epilepsy associated with acquired structural epileptic encephalopathy

2018 ◽  
Vol 60 (7) ◽  
pp. 718-723 ◽  
Author(s):  
Mel Michel Villaluz ◽  
Lysa Boissé Lomax ◽  
Trupti Jadhav ◽  
J Helen Cross ◽  
Ingrid E Scheffer
Keyword(s):  
Ketogenic Diet ◽  
Refractory Epilepsy ◽  
Epileptic Encephalopathy
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