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Gong L, Jin Y, Zhao S, Wang K, Martínez-Alanis PR, Cabot A. Electrocatalytic Oxidation of Benzaldehyde on Gold Nanoparticles Supported on Titanium Dioxide. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1005. [PMID: 38921881 PMCID: PMC11206298 DOI: 10.3390/nano14121005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/27/2024]
Abstract
The electrooxidation of organic compounds offers a promising strategy for producing value-added chemicals through environmentally sustainable processes. A key challenge in this field is the development of electrocatalysts that are both effective and durable. In this study, we grow gold nanoparticles (Au NPs) on the surface of various phases of titanium dioxide (TiO2) as highly effective electrooxidation catalysts. Subsequently, the samples are tested for the oxidation of benzaldehyde (BZH) to benzoic acid (BZA) coupled with a hydrogen evolution reaction (HER). We observe the support containing a combination of rutile and anatase phases to provide the highest activity. The excellent electrooxidation performance of this Au-TiO2 sample is correlated with its mixed-phase composition, large surface area, high oxygen vacancy content, and the presence of Lewis acid active sites on its surface. This catalyst demonstrates an overpotential of 0.467 V at 10 mA cm-2 in a 1 M KOH solution containing 20 mM BZH, and 0.387 V in 100 mM BZH, well below the oxygen evolution reaction (OER) overpotential. The electrooxidation of BZH not only serves as OER alternative in applications such as electrochemical hydrogen evolution, enhancing energy efficiency, but simultaneously allows for the generation of high-value byproducts such as BZA.
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Affiliation(s)
- Li Gong
- Catalonia Institute for Energy Research–IREC Sant Adrià de Besòs, 08930 Barcelona, Spain
- Faculty of Chemistry, University of Barcelona, 08028 Barcelona, Spain
| | - Yu Jin
- Key Laboratory of Applied Organic Chemistry (SKLAOC), The Key Laboratory of Catalytic Engineering of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China;
| | - Shiling Zhao
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
| | - Kaizhi Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China
| | | | - Andreu Cabot
- Catalonia Institute for Energy Research–IREC Sant Adrià de Besòs, 08930 Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
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Waldman HS, O'Neal EK, Barker GA, Witt CR, Lara DA, Huber AK, Forsythe VN, Koutnik AP, D'Agostino DP, Staiano W, Egan B. A Ketone Monoester with Carbohydrate Improves Cognitive Measures Postexercise, but Not Performance in Trained Females. Med Sci Sports Exerc 2024; 56:725-736. [PMID: 38051034 DOI: 10.1249/mss.0000000000003352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
PURPOSE The acute ingestion of a ketone monoester with the coingestion of a carbohydrate (KME + CHO) compared with carbohydrate (CHO) was investigated on cycling performance and cognitive performance in trained females. METHODS Using a two condition, placebo-controlled, double-blinded and crossover design, 12 trained females (mean ± SD: age, 23 ± 3 yr; height, 1.64 ± 0.08 m; mass, 65.2 ± 12.7 kg) completed a baseline assessment of cognitive performance (psychomotor vigilance testing (PVT), task switching, and incongruent flanker), followed by 6 × 5-min intervals at 40%, 45%, 50%, 55%, 60%, and 65% of their maximal power output (W max ) and then a 10-km time trial, concluding with the same assessments of cognitive performance. Participants consumed either 375 mg·kg -1 body mass of KME with a 6% CHO solution (1 g·min -1 of exercise) or CHO alone, across three boluses (50:25:25). RESULTS Blood β-hydroxybutyrate concentrations averaged 1.80 ± 0.07 and 0.13 ± 0.01 mM during exercise in KME + CHO and CHO, respectively. Blood glucose decreased after drink 1 of KME + CHO (~15%; P = 0.01) but not CHO, and lactate concentrations were lower in KME + CHO at 50%, 55%, 60%, and 65% W max (all P < 0.05) compared with CHO. Despite these changes, no differences were found between conditions for time trial finishing times (KME + CHO, 29.7 ± 5.7 min; CHO, 29.6 ± 5.7 min; P = 0.92). However, only KME + CHO resulted in increases in psychomotor vigilance testing speed (~4%; P = 0.01) and faster reaction times (~14%; P < 0.01), speed (~15%; P < 0.01), and correct responses (~13%; P = 0.03) in the incongruent flanker during posttesting compared with CHO. CONCLUSIONS The acute ingestion of a KME + CHO elevated blood β-hydroxybutyrate and lowered glucose and lactate across multiple time points during exercise compared with CHO. Although these changes did not affect physical performance, several markers of cognitive performance were improved by the addition of a KME in trained females.
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Affiliation(s)
- Hunter S Waldman
- Department of Kinesiology, University of North Alabama, Florence, AL
| | - Eric K O'Neal
- Department of Kinesiology, University of North Alabama, Florence, AL
| | - Gaven A Barker
- Department of Kinesiology, University of North Alabama, Florence, AL
| | - Craig R Witt
- Department of Kinesiology, University of North Alabama, Florence, AL
| | - David A Lara
- Department of Kinesiology, University of North Alabama, Florence, AL
| | - Anna K Huber
- Department of Kinesiology, University of North Alabama, Florence, AL
| | | | | | | | - Walter Staiano
- Department of Physical Education and Sport, University of Valencia, Valencia, SPAIN
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Dörner R, Hägele FA, Müller MJ, Seidel U, Rimbach G, Bosy-Westphal A. Effect of exogenous and endogenous ketones on respiratory exchange ratio and glucose metabolism in healthy subjects. Am J Physiol Cell Physiol 2024; 326:C1027-C1033. [PMID: 38314726 PMCID: PMC11193512 DOI: 10.1152/ajpcell.00429.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/07/2024]
Abstract
This study examined the effect of exogenous ketone bodies (KB) on oxygen consumption (V̇o2), carbon dioxide production (V̇co2), and glucose metabolism. The data were compared with the effects of endogenous ketonemia during both, a ketogenic diet or fasting. Eight healthy individuals [24.1 ± 2.5 yr, body mass index (BMI) 24.3 ± 3.1 kg/m2] participated in a crossover intervention study and were studied in a whole-room indirect calorimeter (WRIC) to assess macronutrient oxidation following four 24-h interventions: isocaloric controlled mixed diet (ISO), ISO supplemented with ketone salts (38.7 g of β-hydroxybutyrate/day, EXO), isocaloric ketogenic diet (KETO), and total fasting (FAST). A physical activity level of 1.65 was obtained. In addition to plasma KB, 24-h C-peptide and KB excretion rates in the urine and postprandial glucose and insulin levels were measured. Although 24-h KB excretion increased in response to KETO and FAST, there was a modest increase in response to EXO only (P < 0.05). When compared with ISO, V̇o2 significantly increased in KETO (P < 0.01) and EXO (P < 0.001), whereas there was no difference in FAST. V̇co2 increased in EXO but decreased in KETO (both P < 0.01) and FAST (P < 0.001), resulting in 24-h respiratory exchange ratios (RER) of 0.828 ± 0.024 (ISO) and 0.811 ± 0.024 (EXO) (P < 0.05). In response to EXO there were no differences in basal and postprandial glucose and insulin levels, as well as in insulin sensitivity. When compared with ISO, EXO, and KETO, FAST increased homeostatic model assessment β-cell function (HOMA-B) (all P < 0.05). In conclusion, at energy balance exogenous ketone salts decreased respiratory exchange ratio without affecting glucose tolerance.NEW & NOTEWORTHY Our findings revealed that during isocaloric nutrition, additional exogenous ketone salts increased V̇o2 and V̇co2 while lowering the respiratory exchange ratio (RER). Ketone salts had no effect on postprandial glucose metabolism.
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Affiliation(s)
- Rebecca Dörner
- Department of Human Nutrition, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
| | - Franziska A Hägele
- Department of Human Nutrition, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
| | - Manfred J Müller
- Department of Human Nutrition, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
| | - Ulrike Seidel
- Department of Food Sciences, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
| | - Gerald Rimbach
- Department of Food Sciences, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
| | - Anja Bosy-Westphal
- Department of Human Nutrition, Institute of Human Nutrition and Food Sciences, Kiel University, Kiel, Germany
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Robberechts R, Poffé C. Defining ketone supplementation: the evolving evidence for postexercise ketone supplementation to improve recovery and adaptation to exercise. Am J Physiol Cell Physiol 2024; 326:C143-C160. [PMID: 37982172 DOI: 10.1152/ajpcell.00485.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 11/21/2023]
Abstract
Over the last decade, there has been a growing interest in the use of ketone supplements to improve athletic performance. These ketone supplements transiently elevate the concentrations of the ketone bodies acetoacetate (AcAc) and d-β-hydroxybutyrate (βHB) in the circulation. Early studies showed that ketone bodies can improve energetic efficiency in striated muscle compared with glucose oxidation and induce a glycogen-sparing effect during exercise. As such, most research has focused on the potential of ketone supplementation to improve athletic performance via ingestion of ketones immediately before or during exercise. However, subsequent studies generally observed no performance improvement, and particularly not under conditions that are relevant for most athletes. However, more and more studies are reporting beneficial effects when ketones are ingested after exercise. As such, the real potential of ketone supplementation may rather be in their ability to enhance postexercise recovery and training adaptations. For instance, recent studies observed that postexercise ketone supplementation (PEKS) blunts the development of overtraining symptoms, and improves sleep, muscle anabolic signaling, circulating erythropoietin levels, and skeletal muscle angiogenesis. In this review, we provide an overview of the current state-of-the-art about the impact of PEKS on aspects of exercise recovery and training adaptation, which is not only relevant for athletes but also in multiple clinical conditions. In addition, we highlight the underlying mechanisms by which PEKS may improve exercise recovery and training adaptation. This includes epigenetic effects, signaling via receptors, modulation of neurotransmitters, energy metabolism, and oxidative and anti-inflammatory pathways.
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Affiliation(s)
- Ruben Robberechts
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Chiel Poffé
- Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
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Brady AJ, Egan B. Acute Ingestion of a Ketone Monoester without Co-ingestion of Carbohydrate Improves Running Economy in Male Endurance Runners. Med Sci Sports Exerc 2024; 56:134-142. [PMID: 37565450 DOI: 10.1249/mss.0000000000003278] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
PURPOSE Acute ingestion of a ketone monoester, with and without co-ingestion of carbohydrate, was investigated for effects on running economy (RE), time to exhaustion (TTE), and other related indices of endurance running performance. METHODS Using a three condition, placebo-controlled, randomized crossover design, 11 male middle- and long-distance runners ran at five submaximal speeds (10-14 km·h -1 ) on a motorized treadmill for 8 min each, immediately followed by a ramp test to volitional exhaustion. Participants consumed either a 10% carbohydrate solution (CHO), a 10% carbohydrate solution with 750 mg·kg -1 body mass of an ( R )-3-hydroxybutyl ( R )-3-hydroxybutyrate ketone monoester (CHO + KE), or 750 mg·kg -1 body mass of the ketone monoester in flavored water (KE) before (two-thirds of the dose) and during (one-third of the dose) exercise. RESULTS β-hydroxybutyrate concentration averaged 1.8 ± 0.3 and 2.1 ± 0.3 mM during exercise in CHO + KE and KE, respectively. RE was lower at each submaximal running speed (effect size = 0.48-0.98) by an average of 4.1% in KE compared with CHO, but not between CHO + KE and CHO. TTE did not differ between CHO (369 ± 116 s), CHO + KE (342 ± 99 s), or KE (333 ± 106 s) ( P = 0.093). CONCLUSIONS Acute ingestion of a ketone monoester without carbohydrate, but not when coingested with carbohydrate, improved RE in middle- and long-distance runners at a range of submaximal running speeds and did not alter TTE in a short-duration ramp test to volitional exhaustion. Further investigation is required to examine if these differences translate into positive performance outcomes over longer durations of exercise.
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Margolis LM, Pasiakos SM, Howard EE. High-fat ketogenic diets and ketone monoester supplements differentially affect substrate metabolism during aerobic exercise. Am J Physiol Cell Physiol 2023; 325:C1144-C1153. [PMID: 37721006 PMCID: PMC10635661 DOI: 10.1152/ajpcell.00359.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/19/2023]
Abstract
Chronically adhering to high-fat ketogenic diets or consuming ketone monoester supplements elicits ketosis. Resulting changes in substrate metabolism appear to be drastically different between ketogenic diets and ketone supplements. Consuming a ketogenic diet increases fatty acid oxidation with concomitant decreases in endogenous carbohydrate oxidation. Increased fat oxidation eventually results in an accumulation of circulating ketone bodies, which are metabolites of fatty acids that serve as an alternative source of fuel. Conversely, consuming ketone monoester supplements rapidly increases circulating ketone body concentrations that typically exceed those achieved by adhering to ketogenic diets. Rapid increases in ketone body concentrations with ketone monoester supplementation elicit a negative feedback inhibition that reduces fatty acid mobilization during aerobic exercise. Supplement-derived ketosis appears to have minimal impact on sparing of muscle glycogen or minimizing of carbohydrate oxidation during aerobic exercise. This review will discuss the substrate metabolic and associated aerobic performance responses to ketogenic diets and ketone supplements.
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Affiliation(s)
- Lee M Margolis
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Stefan M Pasiakos
- Office of Dietary Supplements, U.S. Department of Health and Human Services, National Institutes of Health, Bethesda, Maryland, United States
| | - Emily E Howard
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
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Gonzalez JT. Ketone Esters and Their Effects on Carbohydrate Metabolism During Exercise. J Nutr 2023; 153:1663-1664. [PMID: 37054809 DOI: 10.1016/j.tjnut.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/07/2023] [Indexed: 04/15/2023] Open
Affiliation(s)
- Javier T Gonzalez
- Centre for Nutrition, Exercise and Metabolism, Department for Health, University of Bath, Bath, United Kingdom.
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