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Proton Therapy Dosimetry
Published in Arash Darafsheh, Radiation Therapy Dosimetry: A Practical Handbook, 2021
Michele M. Kim, Eric S. Diffenderfer
There are many ways to measure proton beams. Absolute dosimetry can be performed with calorimeters, FCs, and ICs, to name a few. Calorimeters are devices that measure changes in heat generated per unit mass of absorbing material. Corrections for calorimeters include a small estimate of the fraction of energy that goes into induction of chemical changes rather than heat.
Measurement Techniques
Published in Marvin C. Ziskin, Peter A. Lewin, Ultrasonic Exposimetry, 2020
Marvin C. Ziskin, Peter A. Lewin
An example of the flow calorimeter has been described by Szilard.1 It consists of two parts (one irradiated with ultrasound, the other heated electrically) through which the liquid flows continuously. The temperature elevations in the two parts are compared with each other. The calorimeter liquid chiefly used is water. The sensitivity of the instrument is given as 0.1 W; a power of 1 W is stated to be fairly well measurable.
Thermochemistry Calculations Heat Capacity and Enthalpy
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
Calorimetry is the experimental method for measurement of heat transfer. A calorimeter is an insulated container that isolates both the system and surroundings (the calorimeter plus contents) from the rest of the universe; heat transfer to outside the calorimeter is designed to be approximately zero. A constant pressure calorimeter is an open insulated container that allows the pressure to remain constant at atmospheric pressure; in this case, volume can expand. Under these conditions, heat transfer is a measure of ∆H (qp). A constant volume calorimeter is a sealed insulated container that does not allow volume to expand; in this case, pressure may change. Under these conditions, heat transfer is a measure of ∆E (qv).
A Pilot Controlled Feeding Trial Modifying Protein Intake in Healthy Subjects to Assess Adherence and the Metabolome
Published in Nutrition and Cancer, 2023
Josephine Connolly-Schoonen, Lorraine Danowski, Melissa Bistricer, Leslie Campo Catalan, Sarina Ailawadi, Emily M. Sicinski, Martien Schoonen, Brian Ingram, David C. Montrose
Subjects were recruited through email blasts to students and employees of Stony Brook University and flyers distributed on campus. These advertisements contained QR codes directing potential participants to an initial QualtricsXM survey to determine initial eligibility, willingness to avoid alcohol and commit to only eating food provided for the study for six weeks. Individuals meeting these criteria were scheduled for an in-depth in-person screening. After a review of study requirements, subjects were consented, height and weight measured and a health survey completed to finalize eligibility. Energy needs were determined using indirect calorimetry (MedGem® Microlife Calorimeter, Medical Holm Solutions, Golden, CO) and subjects were instructed to keep a three-day food record using a QualtricsXM® survey (October, 2019) (Qualtrics, Provo, UT). Food records were analyzed using Food Processor® nutrition analysis software to estimate habitual energy and macronutrient intake. Lastly, after reviewing the two potential 3-day cycle menus, subjects selected their preferred menu style (Table S1). In addition to meals, subjects were given a $300 honorarium divided into three payments across the study period.
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.
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.