Basic Principles of Ultrasonic Imaging
Asim Kurjak in CRC Handbook of Ultrasound in Obstetrics and Gynecology, 2019
We can describe a sound wave in many ways. We can describe it as a traveling disturbance of the medium or as a traveling pressure wave, etc. All these descriptions are valid and are used in discussions of sound characteristics and effects. Usually, a description which suits the particular problem best is used, although different authors have different definitions for “most suitable”. However, for us, it is important to remember that many descriptions are possible. From now on, we shall describe sound waves as pressure waves because many effects of interest depend on the pressure variations. The energy in our case can be defined as ability to do some work. We cannot see or measure the energy itself. We can only detect it by observing the effects which are produced when the energy changes or is spent in some way. The amount of energy spent is equal to the work done.
Bioenergetics
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan in Strength and Conditioning in Sports, 2023
From a biological standpoint, energy is the ability or capacity to perform work. Energy can be conceptualized as either potential (stored) or kinetic (performing work). Various forms of energy exist; for example, elastic, nuclear, electromagnetic, mechanical, and chemical. Biochemical processes form the basis of metabolism and metabolic energy transformations are necessary for all activities accomplished by living systems. Indeed, the concepts of specificity of exercise and training depend to a great extent upon understanding underlying aspects of metabolism, energy use, and generation. Background knowledge of how energy is created for different types of exercises, and how specific types of training can modify energy production, can lead to more efficient and efficacious designs for training programs. Thus, a thorough understanding of bioenergetics and metabolism is necessary for sport scientists and coaches alike.
Haemodynamics: flow, pressure and resistance
Neil Herring, David J. Paterson in Levick's Introduction to Cardiovascular Physiology, 2018
Darcy’s law deals with pressure, but this is only one of three kinds of mechanical energy that affect flow. The other two are gravitational potential energy and kinetic energy, as recognized by Bernoulli, an 18th-century Swiss mathematician and physicist, who became a professor of mathematics at the age of 25. Bernoulli’s theory states that the energy loss between points A and B, in the steady state, is the difference in the mechanical energy of the fluid; and the mechanical energy is the sum of the pressure energy, potential energy and kinetic energy:Pressure energy equals pressure x volume, P x V.Potential (gravitational) energy is the capacity of a mass to do work in a gravitational field by virtue of its height. The potential energy of blood relative to the heart is the blood mass (volume V x density p) x height above the heart h x acceleration due to gravity g.Kinetic energy is the energy of movement. It depends on mass and velocity, increasing in proportion to velocity squared (v2). The kinetic energy of flowing blood is pVv2/2, where V is blood volume.
The systems view of life: Undergirding and unifying three philosophies of occupation
Published in Journal of Occupational Science, 2018
At the micro levels of life, quantum physics describes relations among molecules, atoms, and particles, and contributes to our understanding of energy (Capra & Luisi, 2014). Energy is commonly understood as the ability to work and is frequently paired with the concept of activity (Capra & Luisi, 2014). Activities are intertwined in occupations: embedded, directing, or otherwise entangled (Pierce, 2001b). In all cases, they represent a dynamic relationship between inner and outer worlds and therefore have potential to hold meaning. Activities that do not hold personal meaning may reflect the original interpretation of the second law of thermodynamics which describes the loss of useful energy to heat or friction. Where meaning forges more and deeper connections between the outer world and inner dimensions, new and intricate connections can be established in different aspects (social, emotional, spiritual, etc.) of the individual. These new connections would resonate with the existing bank of experiences, raising the rate of molecular vibration as the new information is engaged (Capra & Luisi, 2014; Pert, 1997), and stimulating a re-organization (perhaps subtle) of the existing pattern of experience.
Novel pyrrolopyrimidine derivatives: design, synthesis, molecular docking, molecular simulations and biological evaluations as antioxidant and anti-inflammatory agents
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Amira I. Sayed, Yara E. Mansour, Mohamed A. Ali, Omnia Aly, Zainab M. Khoder, Ahmed M. Said, Samar S. Fatahala, Rania H. Abd El-Hameed
Similar results were obtained from the molecular simulations of complexes of 4b and 8e with TLR-4. The TLR-4-4b and TLR-4-8e complexes had RMSD values of 0.18 nm and 0.22 nm, respectively Figure 9(a). Besides, most of the residues of TLR-4-4b and TLR-4-8e complexes reached an average RMSF of 0.19 and 0.21 nm, respectively Figure 9(b). In conclusion, the RMSD and RMSF analysis of the formed complexes between 4b and 8e with COX-2 and TLR-4 showed favourable stability for both the compounds and emphasised the results from the experimental assays. (2) Binding Free Energy Calculations using MM-PBSA approach: attempting to further endorse the binding strength between the COX-2 enzyme and TLR-4 with the newly developed compounds 4b and 8e, the g_mmpbsa package was brought in action to compute the binding free energies between the two targets and the proposed molecules 4b and 8e. The generated trajectories from the production stage were used to calculate all the forms of binding free energy. These energy types include electrostatic energy, van der Waal energy, polar solvation energy and SASA energy. All the previous types of energy were calculated for the four complexes containing COX-2 and TLR-4 bound to 4b or 8e (Table 7).
Heat transfer from nanoparticles for targeted destruction of infectious organisms
Published in International Journal of Hyperthermia, 2018
Michael B. Cortie, David L. Cortie, Victoria Timchenko
The use of an elevated temperature to destroy pathogens has been on a firm scientific footing since the pioneering work of Louis Pasteur in the mid-nineteenth century. However, the industrial process of pasteurisation sterilises almost everything – pathogen or not – in the material that it is applied to. It is only comparatively recently that strategies for selectively applying heat to a specific target cell or organism have been identified. If this can be done efficiently, then destruction would be localised at the position of a target cell or pathogenic organism and collateral damage to the patient’s healthy cells would be minimised. Although several strategies have been considered, the idea of targeting a micro- or nanoparticle to the infectious organism, followed by coupling of an external energy source with the particle, is probably receiving the most attention. Essentially the external source of energy can be light or other electromagnetic radiation, an oscillating magnetic field, ultrasound, or an electric field or current. Depending on the rate and the intensity of the heating, there are two basic outcomes: hyperthermia (increase in local temperature of a few tens of degrees Celsius) and thermoablation. The latter may also involve thermolysis: fragmentation or decomposition of the nanoparticle due to it reaching an extremely high temperature. Of course, if a particle is used then it must be non-toxic, and it should somehow be invisible to the patient’s immune system. There are significant challenges in the field [1–5] but the first clinical use of magnetic hyperthermia has begun [6,7].