The Relation of Vibrator Surface Area and Static Application Force to the Vibrator-to-Head Coupling

1968 ◽  
Vol 11 (4) ◽  
pp. 805-810 ◽  
Author(s):  
E. R. Nilo
Keyword(s):  
Young Adult ◽  
Surface Area ◽  
Unit Area ◽  
Bone Conduction ◽  
Pressure Force ◽  
Adult Men ◽  
Surface Areas ◽  
History Of ◽  
Preliminary Study ◽  
Bone Conduction Hearing

Twelve young adult men with normal hearing and no history of ear disease took part in our study of the relation of vibrator surface area and static application force to the vibrator-to-head coupling. For vibrator surface areas of 1.125, 2.25, and 4.5 cm 2 coupled to the forehead under static forces of 150, 300, and 600 gm, monaural thresholds of bone-conduction hearing were determined at frequencies 250, 500, 1000, and 2000 Hz. With surface area constant, threshold improvement was frequency dependent. It decreased with increasing frequency until at 2000 Hz it was minimal. In contrast to this, with force constant, the influence of surface area was observed to begin at 2000 Hz. Preliminary study suggests this influence would extend to 4000 Hz. In view of the respective influence of application force and surface area to bone-conduction hearing, equating vibrator-to-head coupling on the basis of pressure (force per unit area), when there are two or more vibrators, may not represent an adequate control.

scholarly journals Determination of Testosterone level as predictor for insulin resistance in young men with family history of type2 diabetes and hypertension.

2013 ◽  
Vol 10 (3) ◽  
pp. 945-953
Author(s):  
Baghdad Science Journal
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Risk Factor ◽  
Young Adult ◽  
Family History ◽  
Total Testosterone ◽  
Adult Men ◽  
Type2 Diabetes ◽  
History Of

Background: Insulin resistance is associated with metabolic syndrome , type 2 diabetes and representing a risk factor for cardiovascular disease . This relationship may be modulated to some extent by age related changes in sex hormone status.. In particular, reduced total testosterone (TT) levels have been associated with insulin resistance and subsequent risk for developing type 2 diabetes. Aim of study: we examined whether low total testosterone level were associated with insulin resistance in young adult men. Methods: a total of 83 men (young adult men) divided into 2 group : (group1 ) 49 men with a risk factor for insulin resistance(with a family history of type2 diabetes and hypertension) and (group2) 34 men without any risk factor aged (20-40) years. Age, body mass index (BMI) and waist circumference were measured. Early morning, they were assayed for total testosterone, and insulin levels. Insulin resistance was assessed using a homeostatic model (HOMA-IR). Results: Total testosterone, declined progressively across increasing quintiles of HOMA-IR as a mean of(4.49±1.87) ng/ml in group1 compared mean (7.82±2.21) ng/ml in group 2 and correlated inversely with HOMA-IR( r = -0.424 , p = 002) also with insulin (r= -0.541) (p< 0.0001) in group1 . Total testosterone correlated inversely with BMI (r=-0.471 , p=0.001) in group1. There is a significant positive correlation between HOMA- IR of group1 and BMI (r= 0.472) (p

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

Sign in / Sign up

Export Citation Format

Share Document