Components of Nutrition
Christopher Cumo in Ancestral Diets and Nutrition, 2020
Returning to a general discussion of energy, a piece of laboratory equipment known as a bomb calorimeter measures calories in carbohydrates, fat, and protein. Numbers may vary, clustering near 3.6 calories per gram for the sugar glucose (C6H12O6), 4.1 for starch, 5.6 for protein, and 9.4 for fat.12 Note that glucose and starch, both carbohydrates, differ by half a calorie per gram, debunking the generalization that all carbohydrates have about 4 calories per gram as too imprecise for comfort. Having the most calories by mass, fat is the richest energy source. Alcohol also has calories but will not receive treatment in order to focus on foods rather than beverages. Admittedly the distinction between food and beverage is somewhat arbitrary. Any nourishment may be classified as food. For this reason, part of Chapter 7 examines milk in the conviction that it qualifies as food and beverage. Carbohydrates, fat, and protein aside, the body requires minerals, vitamins, possibly some phytochemicals, and water, none of which has calories.
ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
A calorimeter is a chamber, entirely closed from the outside world, in which one can house an animal and record its body heat. It is used to determine the METABOLIC RATE of small animals—calorimeters for use by large animals (including humans) are used, but less often. Calorimetry is the process of taking such recordings. BOMB CALORIMETRY involves determining the amount of energy present in something by burning it in a sealed unit—a bomb calorimeter—and measuring the heat given off. This is a process occasionally used to determine the energy composition of animal carcasses.
Nutrition for health and sports performance
Nick Draper, Helen Marshall in Exercise Physiology, 2014
It is possible to measure the stored energy in food using a bomb calorimeter; an example of this is shown in Figure 2.6. In a bomb calorimeter the food to be tested is burned completely within a chamber containing oxygen and started by an electrical ignition. The burning of the foodstuff will result in the release of heat energy.
Discovery of RNA-targeted small molecules through the merging of experimental and computational technologies
Published in Expert Opinion on Drug Discovery, 2023
The gold standard for obtaining binding constants and thermodynamic parameters for target–ligand interactions is ITC [143]. During an ITC experiment, a ligand (small molecule) solution is typically injected into a sample cell containing the label-free target biomolecule (RNA) (Figure 4(a)). A sensitive calorimeter measures the heat released or absorbed during titration until the binding reaction has reached equilibrium. The measured heat values are then used to obtain the binding affinity (KD), stoichiometry (N), and change in enthalpy (∆H), from which the changes in free energy (∆G) and entropy (∆S) are calculated. Obtaining these thermodynamic parameters for binding of the hit compounds to the target RNA can help in compound classification and prioritization at a later stage. Although a trusted technique, ITC requires large amounts of sample and high solubility of the small-molecule compound.
The specific heat of the human body is lower than previously believed: The journal Temperature toolbox
Published in Temperature, 2023
Xiaojiang Xu, Timothy P. Rioux, Michael P. Castellani
Our method is novel and calculates the specific heat of the body from the tissue masses and tissue specific heat according to the definition of the body specific heat described in Equation (1). A calorimeter can be used to measure the specific heat of individual tissue [4], but not the specific heat of the whole body. This is primarily because the calculation of the mean body temperature, either from the core and skin or from the core, muscle, and skin temperatures, requires coefficients that are inconsistent across studies, difficult to determine accurately, and dependent on the body thermal status [1,8,9]. In our new method, the masses of body tissues are derived from the medical images of volunteers [6,7]. Many specific heat values in Table 2 were measured and some were estimated from the tissue composition and water content [4,5]. Thus, the specific heat determined by our new method can be considered a measured value. As heat content is an important parameter for the assessment of human thermal status [1,10–16], we believe this new information will improve the accuracy of calculations related to human heat balance in future studies of exercise, thermal stress, and related areas.
The impact of data selection and fitting on SAR estimation for magnetic nanoparticle heating
Published in International Journal of Hyperthermia, 2020
Hattie L. Ring, Anirudh Sharma, Robert Ivkov, John C. Bischof
The challenges of reliably comparing SARv across laboratories are related to the complex nature of the heat losses involved with the heating system and the sample. Most research findings report field strength, field amplitude, and sample information; however, many details related to the experimental setup are necessary to understand the heat losses within the system. Calibration of calorimeter, field properties, and other components of the apparatus are rarely performed, presenting significant challenges for comparisons absent standard reference materials. Additionally, the precision and accuracy with which the iron content is quantified will affect the calculated SLP. While ICP-MS is the gold-standard for iron quantification due to its sensitivity (ng/L detection limits), less expensive spectrophotometric assays have been optimized to measure iron content in 0.1–1μg/mL range [22,23], which should be suitable for SLP evaluation. Finally, the sample volume used for measurements has been shown to critically affect the results, likely due to heat transfer between sample and environment [27,28]. We recommend researchers report at least the experimental details listed in Table 2 to indicate the sample preparation and heat losses within an experimental setup. Finally, it cannot be overlooked that each experimental setup has an optimal range of SARv and adjustment of IONP concentration to be within that range can reduce variation results caused by fitting method.
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