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Relation Between Contraction and Metabolic Efficiency
Published in Samuel Sideman, Rafael Beyar, Analysis and Simulation of the Cardiac System — Ischemia, 2020
Joseph Kedem, M. Scheinowitz, E. Furman, J. Sonn, H. R. Weiss
You showed essentially tension/length-type measurements. Tension times length is not going to give you work; it is going to give you force. I was wondering what your measurement actually is. Do you truly have a tension gauge and a length gauge? If so, what you showed is not work; it is force. If you had a force gauge, then you would have work. This may explain why there is a discrepancy. In other words, your measurements may not be measurements of absolute work. They may only be relative.
Experimental Methods in Cardiovascular Mechanics
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
Regardless of whether one piece of testing equipment is intrinsically better suited to carry out displacement- or force-controlled protocols, it is interesting to note the following: with equibiaxial displacement testing (green dashed line in Figure 4.2), it is possible to miss the upward turn in the curve for the softer direction of the material (and possibly that in the curve for the stiffer direction as well) if the range of displacements is not large enough, or if the capacity of the force gauge is too low in the axis of the stiffer direction of the material. With equibiaxial force testing (black dashed line in Figure 4.2), one could miss both upward turns if the applied force is not high enough, but if it is high enough, assuming that displacements are not restricted, the upward turns of the curves for both the softer and stiffer directions of the material will be properly captured. Based on these observations, efficient testing protocols can be devised to simulate equibiaxial and general force-controlled testing by using displacement-controlled equipment (Labrosse et al. 2016).
Infertility Diagnosis and Treatment
Published in Sujoy K. Guba, Bioengineering in Reproductive Medicine, 2020
Column model suggests that an approach to the quantification of penile rigidity is to measure the force P. A simple way to perform the measurement is to have the subject lying down and then press down on the glans penis with a dial type of force gauge (Figure 4.16). Dial reading in kilograms when buckling is prominent is the buckling force. Frahrib et al.50 have conducted studies on subjects with erectile dysfunctions after producing erection with intracavernous injection of a mixture of papaverine hydrochloride and phentolamine neoylate. If patient had a poor penile venous closure mechanism and erection was not maintained spontaneously following the drug treatment, they continuously infused heparinized saline into the corpus cavernosum of patients. In subjects with adequate venous closure the corporal body pressure, as measured with a catheter and a pressure transducer, was sustained with occasional pulsed infusion of saline. Axial loading for buckling force assessment was repetitively applied for short durations of 5 to 10 s. A radial rigidity equivalent to circumferential rigidity was also determined. Two loops placed around the proximal and distal penile shaft measured the penile circumference. When the circumference increased by 1 cm, a controlled tensile force of 2.78 N (10 oz) was applied to the loops and released every 30 seconds. Distortion of the penis from its unstressed state was interpreted as circumferential rigidity. The study demonstrated that circumferential and axial rigidities are related to the corporal body pressure but not to penile circumferential changes. As corporal pressure falls, rigidity declines but tumescence and circumferential girth remain unaffected. This finding, if substantiated by further research, would call for a radical review of the interpretation of tumescence data vis a vis impotence.
Measurement of trunk muscle strength after stroke: An integrative review
Published in Topics in Stroke Rehabilitation, 2022
Relevant studies were conducted in 8 countries with the largest number originating in Japan, Brazil, and the United States. Most of the participants with stroke were in the subacute or chronic stage of recovery. Trunk strength was measured in the majority of studies (n = 20) while participants were sitting and most often under isometric conditions using some model of hand-held dynamometer or modified sphygmomanometer (10 studies). However, a Cybex or Biodex isokinetic dynamometer was used with 8 studies of sitting or standing participants. The majority of these studies involved the measurement of isometric strength, but some of the studies measured concentric strength as well – at speeds ranging from 60⁰/s to 150⁰/s. The 4-category abdominal strength score of the Stroke Impairment Assessment Scale (SIAS) was used in 7 studies. The SIAS abdominal strength scores were based on a patient’s ability to sit up from a 45⁰ semi-reclined position (0 = unable to sit up, 1 = able to sit up, 2 = able to sit up despite tester’s application of pressure on sternum, 3 = able sit up despite considerable resistance).15 Two studies employed an instrumented Spine Balance System. A single study used a fixed force gauge. The strength of 1 or more trunk motions (ie, sagittal flexion, sagittal extension, lateral flexion, or rotation) was measured in the reviewed studies, but trunk flexion strength was measured most frequently.
The effect of bone vibrator coupling method on the neonate auditory brainstem response
Published in International Journal of Audiology, 2019
Andrew Stuart, Hannah M. Nelson
The bone vibrator was placed in a temporal area supero-posterior auricular position (Stuart, Yang, and Stenstrom 1990) in all three test conditions: In the first “hand-held” condition, the tester manually held the bone vibrator with no applied force. In the second hand-held “force gauge” condition, the force gauge described above was manually held in place. Testing began when the LED light was maintained in the Green (450–550 g) position and remained so throughout testing (Figure 1). In the third “band” condition, an elastic band with Velcro was used to hold the bone vibrator with a coupling force of 425 ± 25 g (Yang and Stuart 1990). A spring scale (Ohaus 8014) was used to verify the coupling force. The spring scale manually pulled the bone vibrator away from the skull by a nylon monofilament attached to the bone vibrator. When the vibrator cleared and became level with the surface of the scalp, the coupling force was measured (Figure 2).
Neonate auditory brainstem response repeatability with controlled force gauge bone-conducted stimulus delivery
Published in International Journal of Audiology, 2018
Andrew Stuart, Hannah M. Dorothy
Previous researchers have demonstrated various bone vibrator coupling methods to be reliable in the assessment of evoked potentials with neonates and young infants. Yang et al. (1993) and Small, Hatton, and Stapells (2007) have shown repeatable neonate ABRs and auditory steady-state responses, respectively, with an elastic band coupling of the bone vibrator to the cranium. Recently, Cobb and Stuart (2014) confirmed the same with neonate ABRs to chirp stimuli. They examined 30 newborns. ABRs were evoked with 45, 30, and 15 dB nHL BC CE-Chirps. Two different testers repeated all measures. They found statistically significant correlations and predictive linear relations between the two testers for wave V latencies and amplitudes. Small, Hatton, and Stapells (2007), as noted above, also established that a hand-held coupling method is comparable to and evidence the same variability as the elastic band coupling method provided trained personal are utilised. The findings of the present study suggest that the hand-held applied force gauge is also a reliable means of delivering controlled BC stimuli in ABR assessments in neonates. As such, the handheld applied force gauge provides another alternative for bone vibrator coupling in the electrophysiological diagnostic audiologic assessments of newborns.