Review

Authors: Rodrigo Fernández-Verdejo, Guillermo Sanchez-Delgado, Eric Ravussin...

Humans require energy to sustain their daily activities throughout their lives. This narrative review aims to () summarize principles and methods for studying human energy expenditure, () discuss the main determinants of energy expenditure, and () discuss the changes in energy expenditure throughout the human life course. Total daily energy expenditure is mainly composed of resting energy expenditure, physical activity energy expenditure, and the thermic effect of food. Total daily energy expenditure and its components are estimated using variations of the indirect calorimetry method. The relative contributions of organs and tissues determine the energy expenditure under different physiological conditions. Evidence shows that energy expenditure varies along the human life course, at least in part due to changes in body composition, the mass and specific metabolic rates of organs and tissues, and levels of physical activity. This information is crucial to estimate human energy requirements for maintaining health throughout the life course.

Topics: Humans; Energy Metabolism; Body Composition; Exercise; Calorimetry, Indirect

PubMed: 38759093
DOI: 10.1146/annurev-nutr-062122-031443

Review

Authors: Matthew N Cramer, Ollie Jay

For thermal physiologists, calorimetry is an important methodological tool to assess human heat balance during heat or cold exposures. A whole body direct calorimeter remains the gold standard instrument for assessing human heat balance; however, this equipment is rarely available to most researchers. A more widely accessible substitute is partitional calorimetry, a method by which all components of the conceptual heat balance equation-metabolic heat production, conduction, radiation, convection, and evaporation-are calculated separately based on fundamental properties of energy exchange. Since partitional calorimetry requires relatively inexpensive equipment (vs. direct calorimetry) and can be used over a wider range of experimental conditions (i.e., different physical activities, laboratory or field settings, clothed or seminude), it allows investigators to address a wide range of problems such as predicting human responses to thermal stress, developing climatic exposure limits and fluid replacement guidelines, estimating clothing properties, evaluating cooling/warming interventions, and identifying potential thermoregulatory dysfunction in unique populations. In this Cores of Reproducibility in Physiology (CORP) review, we summarize the fundamental principles underlying the use of partitional calorimetry, present the various methodological and arithmetic requirements, and provide typical examples of its use. Strategies to minimize estimation error of specific heat balance components, as well as the limitations of the method, are also discussed. The goal of this CORP paper is to present a standardized methodology and thus improve the accuracy and reproducibility of research employing partitional calorimetry.

Topics: Animals; Body Temperature Regulation; Calorimetry; Energy Metabolism; Humans; Models, Biological; Predictive Value of Tests; Reproducibility of Results; Sweating; Thermogenesis

PubMed: 30496710
DOI: 10.1152/japplphysiol.00191.2018

Authors: Oana Alina Tatucu-Babet, Emma Jean Ridley

Topics: Calorimetry, Indirect; Humans; Psychometrics

PubMed: 31477499
DOI: 10.1016/j.jphys.2019.07.002

Review

Authors: Agnes Rodler, Rene Ueberbacher, Beate Beyer...

Hydrophobic interaction chromatography is a very popular chromatography method for purification of proteins and plasmids in all scales from analytical to industrial manufacturing. Despite this frequent use, the complex interaction mechanism and the thermodynamic aspects of adsorption in hydrophobic interaction chromatography are still not well understood. Calorimetric methods such as isothermal titration calorimetry and flow calorimetry can help to gain a deeper understanding of the adsorption strength, the influence of salt type and temperature. They can be used to study conformational changes of proteins, which are often associated with the adsorption in hydrophobic interaction chromatography. This review offers a detailed introduction into the thermodynamic fundamentals of adsorption in hydrophobic interaction chromatography with a special focus on the potential applications of isothermal titration calorimetry and flow calorimetry for studying specific problems and relationships of the adsorption behavior of proteins and its various influencing factors. Models for characterizing conformational changes upon adsorption are presented together with methods for assessing this problem for different proteins and stationary phases. All of this knowledge can contribute greatly to forming a sound basis for method development, process optimization and finding modelling strategies in hydrophobic interaction chromatography.

Topics: Adsorption; Calorimetry; Chromatography, Liquid; Hydrophobic and Hydrophilic Interactions; Proteins; Thermodynamics

PubMed: 30735098
DOI: 10.1080/10826068.2018.1487852

Authors: Zane Hopper, Ben Desbrow, Shelley Roberts...

Standardised bomb calorimetry methods are essential to accurately quantify the gross energy within food and beverages, yet no accepted protocols exist. The objective of this review was to synthesise literature on food and beverage sample preparation methods used for conducting bomb calorimetry. This synthesis enhances our understanding of the extent to which methodological variances may currently affect estimates of the caloric values of dietary items. Five electronic databases were searched for peer reviewed literature on food and beverage energy measurement via bomb calorimetry. Data were extracted on seven identified methodological themes, including: (1) initial homogenisation, (2) sample dehydration, (3) post-dehydration homogenisation, (4) sample presentation, (5) sample weight, (6) sample frequency, and (7) equipment calibration. A tabular and narrative approach was used to synthesise the data. Studies that specifically explored the impact of any methodological variance on the energy derived from foods and/or beverages were also considered. In total, 71 documents describing food and beverage sample preparation techniques and processes used for bomb calorimetry were identified. Only 8% of studies described all seven identified sample preparation and calibration processes. The most frequent approaches used included: initial homogenisation - mixing or blending (n = 21); sample dehydration - freeze drying (n = 37); post-dehydration homogenisation - grinding (n = 24); sample presentation - pelletisation (n = 29); sample weight - 1g (n = 14); sample frequency - duplicate (n = 17); and equipment calibration - benzoic acid (n = 30). The majority of studies that have measured food and beverage energy via bomb calorimetry do not describe sample preparation and calibration methods in detail. The extent to which different sample preparation processes influence the energy derived from food and beverage items is yet to be fully elucidated. Use of a bomb calorimetry reporting checklist (described within) may assist with improving the methodological quality of bomb calorimetry studies.

Topics: Humans; Checklist; Dehydration; Energy Intake; Beverages; Calorimetry

PubMed: 37335168
DOI: 10.38212/2224-6614.3461

Review

Authors: Jean-Paul Renaud, Chun-Wa Chung, U Helena Danielson...

Over the past 25 years, biophysical technologies such as X-ray crystallography, nuclear magnetic resonance spectroscopy, surface plasmon resonance spectroscopy and isothermal titration calorimetry have become key components of drug discovery platforms in many pharmaceutical companies and academic laboratories. There have been great improvements in the speed, sensitivity and range of possible measurements, providing high-resolution mechanistic, kinetic, thermodynamic and structural information on compound-target interactions. This Review provides a framework to understand this evolution by describing the key biophysical methods, the information they can provide and the ways in which they can be applied at different stages of the drug discovery process. We also discuss the challenges for current technologies and future opportunities to use biophysical methods to solve drug discovery problems.

Topics: Animals; Biophysical Phenomena; Calorimetry; Drug Design; Drug Discovery; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Humans; Pharmaceutical Preparations; Surface Plasmon Resonance

PubMed: 27516170
DOI: 10.1038/nrd.2016.123

Authors: Hui Zhang, Huahui Zeng, Mengfei Li...

A series of co-crystals of ascorbic acid were prepared with equimolar amounts of co-crystal formers (CCFs), including isonicotinic acid, nicotinic acid, 3,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid and m-hydroxybenzoic acid, by slow solvent evaporation and solvent-assisted grinding. The co-crystals were characterized by single-crystal X-ray diffraction spectroscopy, powder X-ray diffraction, IR spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Molecular dynamics (MD) simulations further validated the interaction energy and the possible intermolecular hydrogen bonds among VC and CCFs. The co-crystals showed improved stability when exposed to different wavelengths of light, pH and temperatures compared to the free analogue, especially at higher pH (~9) and lower temperature (~4 °C).

Topics: Ascorbic Acid; Powders; Calorimetry, Differential Scanning; Niacin; Solvents

PubMed: 36432100
DOI: 10.3390/molecules27227998

Authors: Conrad L Smart, Alejandro J Cortese, B J Ramshaw...

We present in situ calorimetry, thermal conductivity, and thermal diffusivity measurements of materials using temperature-sensing optical wireless integrated circuits (OWiCs). These microscopic and untethered optical sensors eliminate input wires and reduce parasitic effects. Each OWiC has a mass of ∼100 ng, a 100-μm-scale footprint, and a thermal response time of microseconds. We demonstrate that they can measure the thermal properties of nearly any material, from aerogels to metals, on samples as small as 100 ng and over thermal diffusivities covering four orders of magnitude. They also function over a broad temperature range, and we present proof-of-concept measurements of the thermodynamic phase transitions in both liquid crystal 5CB and gadolinium.

Topics: Thermal Conductivity; Temperature; Calorimetry; Thermodynamics; Liquid Crystals

PubMed: 36367955
DOI: 10.1073/pnas.2205322119

Review

Authors: Kong Y Chen, Steve Smith, Eric Ravussin...

Whole-room indirect calorimeters have been used to study human metabolism for more than a century. These studies have contributed substantial knowledge to the assessment of nutritional needs and the regulation of energy expenditure and substrate oxidation in humans. However, comparing results from studies conducted at different sites is challenging because of a lack of consistency in reporting technical performance, study design, and results. In May 2019, an expert panel was convened to consider minimal requirements for conducting and reporting the results of human whole-room indirect calorimeter studies. We propose Room Indirect Calorimetry Operating and Reporting Standards, version 1.0 (RICORS 1.0) to provide guidance to ensure consistency and facilitate meaningful comparisons of human energy metabolism studies across publications, laboratories, and clinical sites.

Topics: Calorimetry, Indirect; Energy Metabolism; Humans; Reference Standards

PubMed: 32841524
DOI: 10.1002/oby.22928

Authors: Tarek Elsewify, Hisham Elhalabi, Bassem Eid...

INTRODUCTION

The aim of this study was to assess the dynamic cyclic fatigue resistance of an R-Motion file at simulated body temperature and document corresponding phase transformations compared to OneCurve and HyFlex EDM (HFEDM).

METHODS

R-Motion (25/.06), OneCurve (25/.06), and HFEDM (25/.06) files were selected and divided into 3 groups (n = 9) according to the file type. Dynamic cyclic fatigue testing was done with a custom-made artificial stainless-steel canal that had a 90° angle of curvature and a 5-mm radius of curvature. Files were operated continuously at body temperature until fracture in the artificial canal. The time to fracture was calculated. Statistical analysis was performed, and significance was set at 5%. Phase transformation temperatures for 2 instruments of each group were analysed by differential scanning calorimetry (DSC) analysis.

RESULTS

The highest mean time to fracture value was measured in the HFEDM group (277.84 ± 2.51), followed by the R-Motion group (115.09 ± 0.01), whilst the lowest value was found in the OneCurve group (44.28 ± 3.63). Post hoc pairwise comparisons were all statistically significant (P < .001). DSC heating curves show austinite start temperatures to be 33.94 °C and 43.32 °C and austinite finish temperatures to be 35.09 °C and 50 °C for R-Motion and HFEDM, respectively. DSC cooling curves show martensite start temperatures to be 27.54 °C and 44.52 °C and martensite finish temperatures to be 29.13 °C and 37.68 °C for R-Motion and HFEDM, respectively. DSC curves of OneCurve failed to demonstrate transformation temperatures within the tested heat range.

CONCLUSIONS

Crystalline arrangement of Ni and Ti atoms within the NiTi alloys greatly affects the dynamic cyclic fatigue resistance of the file.

Topics: Humans; Equipment Failure; Calorimetry, Differential Scanning; Alloys; Materials Testing; Equipment Design

PubMed: 36631389
DOI: 10.1016/j.identj.2022.12.007