An electromagnetic valve for inspiratory occlusion pressures

1978 ◽  
Vol 45 (3) ◽  
pp. 481-483 ◽  
Author(s):  
E. M. Camporesi ◽  
M. Feezor ◽  
J. Fortune ◽  
J. Salzano
Keyword(s):  
Electronic Circuit ◽  
Breathing Circuit ◽  
Human Subjects ◽  
Respiratory Cycle ◽  
Electromagnetic Valve ◽  
Airway Occlusion ◽  
Co2 Rebreathing ◽  
Respiratory Valve ◽  
Early Phases ◽  
Different Levels

An electromagnetically powered respiratory valve to occlude a respiratory circuit for short (30--300ms) periods of the respiratory cycle may be inexpensively constructed from available laboratory instruments and controlled by an electronic circuit. Occlusion of the inspiratory breathing circuit may be repeated at different levels of ventilation without altering slopes or intercepts of CO2 rebreathing curves. The early phases of airway occlusion (P0.1) may therefore be studied in conscious unanesthetized human subjects.

Sweating and body temperatures following abrupt changes in environmental temperature

1962 ◽  
Vol 17 (1) ◽  
pp. 103-106 ◽  
Author(s):  
H. S. Belding ◽  
B. A. Hertig
Keyword(s):  
Skin Temperature ◽  
Environmental Temperature ◽  
Sweat Rate ◽  
Human Subjects ◽  
Body Temperatures ◽  
Hypothalamic Temperature ◽  
Abrupt Changes ◽  
Consistent Change ◽  
Different Levels ◽  
Skin Receptors

Human subjects were transferred between environments imposing different levels of heat stress. Analyses of measurements obtained after a reasonably steady state had been achieved in each of several environments revealed equally good correlation between a) sweat rate and ear temperature (tympanic membrane), and b) sweat rate and calculated deep skin temperature (hypothetical). The correlations are consistent with adjustment of sweating in response to either hypothalamic temperature or temperature of skin receptors or some combination of the two. However, during the first 20 min after transfer, changes in sweat rate and skin temperature occurred together and in the same direction, but were not accompanied by any consistent change in ear temperature. Thus, to the extent that ear temperature represents hypothalamic temperature, an hypothesis of control of sweating based on hypothalamic temperature alone is not tenable. Alternative physiological explanations are given for data developed elsewhere and used in support of an hypothesis of sweat control solely from the hypothalamus. Submitted on August 14, 1961

Costal and crural diaphragm in early inspiration: free breathing and occlusion

1987 ◽  
Vol 63 (4) ◽  
pp. 1622-1628 ◽  
Author(s):  
P. A. Easton ◽  
J. W. Fitting ◽  
A. E. Grassino
Keyword(s):  
Pressure Measurement ◽  
Neural Control ◽  
Free Breathing ◽  
Inspiratory Effort ◽  
Electromyographic Activity ◽  
Occlusion Pressure ◽  
Airway Occlusion ◽  
Co2 Rebreathing ◽  
Control Patterns ◽  
Crural Diaphragm

Changes in length of costal and crural segments of the canine diaphragm were measured by sonomicrometry within the first 100–300 ms of inspiration during CO2 rebreathing in anesthetized animals. Both segments showed small but significant decreases in end-expiratory length during progressive hypercapnia. Although both costal and crural segments showed electromyographic activity within the first 100 ms of inspiration, in early inspiration crural shortening predominated with minimal costal shortening. Neither segment contracted isometrically early in inspiration in the presence of airway occlusion. The amount of crural shortening during airway occlusion exceeded costal shortening; both segments showed increased shortening with prolonged occlusion and increasing CO2. Costal and crural shortening at 100 ms was not different for unoccluded and occluded states. These observations suggest that neural control patterns evoke discrete and unequal contributions from the diaphragmatic segments at the beginning of an inspiration; the crural segment may be predominately recruited in early inspiration. Despite traditional assumptions about occlusion pressure measurement (P0.1), diaphragm segments do not contract isometrically during early inspiratory effort against an occluded airway.

A Multi-Level Approach to Concept Selection in Sustainable Design

2014 ◽  
Author(s):  
Daniel Stratton ◽  
Sara Behdad ◽  
Kemper Lewis ◽  
Sundar Krishnamurty
Keyword(s):  
Environmental Sustainability ◽  
Utility Score ◽  
Concept Selection ◽  
Trade Offs ◽  
Design Alternatives ◽  
Multi Level ◽  
Early Phases ◽  
Different Levels ◽  
Selection Of ◽  
Lca Results

The motivation behind this work is to integrate economic and environmental sustainability into decision making at the early phases of design through the development of a hierarchical concept selection method. Life Cycle Assessment (LCA) is a frequently implemented technique used to assess the environmental impacts of products, but it does not provide a simple means for including preference at different levels that can be used for comparison across design alternatives. A method is proposed to accommodate this issue expanding the Hypothetical Equivalents and Inequivalents Method (HEIM) to handle multi-level and multi-attribute trade-offs. The selection of a coffee maker design is used as an example to illustrate the implementation of the method with actual LCA results. The example provides valuable insights into how preferences may be elicited at different hierarchical levels and then combined to create a single utility score that represents to what extent each design alternative is preferred by the decision maker.

scholarly journals Comparative study between ECL and ELISA to determine the reliable range of Estradiol in the treatment of infertility

Bionatura ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 1352-1355
Author(s):  
Ali Sadeghitabar ◽  
Narges Maleki ◽  
Maryam Armand ◽  
Nasiri Reza
Keyword(s):  
Human Subjects ◽  
Pearson Correlation ◽  
Diagnostic Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
P Value ◽  
Vitro Fertilization ◽  
The Relationship ◽  
Different Levels ◽  
Estradiol Concentration

Estradiol is one factor that can alter the outcome of the treatment of infertile couples following the application of in vitro fertilization techniques. Currently, the estradiol level is measured by two diagnostic methods Enzyme-Linked Immunosorbent Assay (ELISA) and Electrochemiluminescence (ECL). Accordingly, this study determines ELISA and ECL's sensitivity and consistency to measure different levels of estradiol and determine its reliable range and provide this information to laboratories and gynecologists. This study is performed on 250 patients of the Avicenna Fertility Center. The data of the study are analyzed in SPSS18 and MiniTab. Consent was obtained for experimentation with human subjects. Pearson correlation coefficient was used to investigate the relationship between these two methods. The results indicated a strong correlation between the two variables ECL and ELISA ( r= 0.735, P-value<0.001). High numbers indicate that the decrease and increase of one variable are proportional to the other variable's fluctuation. This study shows that the results of estradiol obtained from both ECL and ELISA are similar. In the ELISA method, due to the linear values' limitation, samples with estradiol concentration above the highest standard level should be diluted and the dilution coefficient should then be applied.

Effects of timing of inspiratory occlusion on cerebral evoked potentials in humans

1990 ◽  
Vol 68 (1) ◽  
pp. 282-288 ◽  
Author(s):  
W. R. Revelette ◽  
P. W. Davenport
Keyword(s):  
Evoked Potentials ◽  
Somatosensory Cortex ◽  
Human Subjects ◽  
Abrupt Decrease ◽  
Airway Occlusion ◽  
Mouth Pressure ◽  
Cerebral Evoked Potentials ◽  
Evoked Potentials In Humans ◽  
Bilateral Projection ◽  
The Right

Previous studies from these laboratories have shown that airway occlusion applied from the onset of inspiration or during midinspiration is associated with cerebral evoked potentials in human subjects. The hypothesis tested in the present study was that the more abrupt decrease in mouth pressure produced by midinspiratory occlusion will be associated with evoked potentials that have shorter peak latencies and greater peak amplitudes than those produced by occlusions from the onset of inspiration. The second objective of the present study was to determine whether there is bilateral projection of inputs from the respiratory system to the somatosensory cortex. Random presentation of 64 midinspiratory occlusions and 64 occlusions from the onset of inspiration was performed in eight subjects. The inspirations preceding the occlusions served as control. Evoked potentials were recorded from the scalp with electrode pairs Cz-C3 and Cz-C4. Reaction time to each type of occlusion was measured from the burst in electromyogram activity produced by contraction of the muscles encircling the eye. Each type of inspiratory occlusion was associated with evoked potentials that could be recorded bilaterally. The peak amplitudes of the evoked potentials recorded over the right cerebral hemisphere were significantly greater than those recorded from the left side. The peak amplitude was greater and the peak latency shorter for the evoked potentials produced by the midinspiratory occlusions. The results are consistent with the hypothesis that afferents mediating these potentials are stimulated by added loads to breathing and project bilaterally to the somatosensory cortex in humans.

scholarly journals The precision of temporal judgement: milliseconds, many minutes, and beyond

2009 ◽  
Vol 364 (1525) ◽  
pp. 1897-1905 ◽  
Author(s):  
P.A. Lewis ◽  
R.C. Miall
Keyword(s):  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Human Subjects ◽  
Short Interval ◽  
Time Measurement ◽  
Scalar Property ◽  
Timing Mechanisms ◽  
Timing Data ◽  
The Mean ◽  
Different Levels

The principle that the standard deviation of estimates scales with the mean estimate, commonly known as the scalar property, is one of the most broadly accepted fundamentals of interval timing. This property is measured using the coefficient of variation (CV) calculated as the ratio between the standard deviation and the mean. In 1997, John Gibbon suggested that different time measurement mechanisms may have different levels of absolute precision, and would therefore be associated with different CVs. Here, we test this proposal by examining the CVs produced by human subjects timing a broad range of intervals (68 ms to 16.7 min). Our data reveal no evidence for multiple mechanisms, but instead show a continuous logarithmic decrease in CV as timed intervals increase. This finding joins other recent reports in demonstrating a systematic violation of the scalar property in timing data. Interestingly, the estimated CV of circadian judgements fits onto the regression of decreasing CV, suggesting a link between short interval and circadian timing mechanisms.

scholarly journals Exhaled air speed measurements of respiratory air flow, generated by ten different human subjects, under uncontrolled conditions

2019 ◽  
Vol 111 ◽  
pp. 02074 ◽  
Author(s):  
Martin Ivanov
Keyword(s):  
Human Subjects ◽  
Air Flow ◽  
Flow Characteristics ◽  
Respiratory Cycle ◽  
Numerical Studies ◽  
Exponential Trend ◽  
Measured Speed ◽  
Air Speed ◽  
The One ◽  
Human Nose

The presented study reveals a multi-point experimental measurement of the airflow speed, generated in the exhalation phase from the human respiratory cycle, based on data from 10 real human subjects. The results obtained demonstrate the exceptional irregularity and the transient character of the human respiratory cycle, in terms of measured speed at different points of man-generated exhalation air flow. The presented exponential trend lines show as expected, that there is a reduction in the exhalation speed, with the increase of the distance from the nose. The summary analysis shows that at 10 cm distance from the nose the maximum as well as the average measured speeds are higher than the one, measured at 5 cm distance. This suggests that due to the physiology of the human nose, 5 cm distance is not enough to characterize the fully developed exhalation jet flow. It is suggested that at this distance the exhalation jets are still two, issuing from each nostril, with different flowrate ratio. The obtained flow characteristics can be used to compare, validate and verify data from conducted numerical studies of the breathing process, via virtual models or real breathing thermal mannikins.

scholarly journals Quantification of Mental Stress using fNIRS Signals

2019 ◽  
Author(s):  
Fares Al-Shargie
Keyword(s):  
Mental Stress ◽  
Task Difficulty ◽  
Near Infrared ◽  
Time Pressure ◽  
Human Subjects ◽  
Difficulty Level ◽  
Functional Near Infrared Spectroscopy ◽  
Arithmetic Task ◽  
Stress Task ◽  
Different Levels

In this study, we propose functional near infrared spectroscopy (fNIRS) to objectively grade different levels of mental stress. The levels of stress were set based on arithmetic task difficulty, time pressure and negative feedback about peer performance. We examined the proposed approach on twelve human subjects using the Montreal Imaging Stress Task. The experiment results revealed a reduction in cortical activations at prefrontal cortex when stressed, and the differences in hemodynamic response between control condition and under stress were significant with mean p-values of 0.0023, 0.00015 and 0.0004 for arithmetic difficulty level one, two and three, respectively. We thus confirm the feasibility of fNIRS in grading mental stress.

TOWARD A NEW DIMENSION IN HUMAN GROWTH

PEDIATRICS ◽  
1965 ◽  
Vol 36 (6) ◽  
pp. 825-835
Author(s):  
Gilbert B. Forbes
Keyword(s):  
Human Subjects ◽  
Human Growth ◽  
The Body ◽  
Tissue Composition ◽  
Early Nineteenth Century ◽  
Systematic Fashion ◽  
Recent Innovation ◽  
Von Liebig ◽  
The University ◽  
Early Phases

It is with a deep sense of appreciation that I accept this honor, and proudly join the roll of distinguished Borden Awardees. In doing so, I should like to pay special tribute to two of my mentors—Dr. William Bradford and the late Dr. Alexis Hartmann—who stimulated and encouraged me in my work, and more importantly, gave me time in which to pursue it; and to Dr. John Hursh, of the University of Rochester Atomic Energy Project, for his most generous collaboration. The measurement of human subjects in systematic fashion is a recent innovation, dating only to the early nineteenth century. This period also marked the rise of modern chemistry, and by mid-century von Liebig had found that sodium was the principal cation in body fluids while potassium was predominant in cells, and Carl Schmidt had analyzed blood serum in great detail. The year 1857 saw the publication of one of the first attempts to analyze the body as a whole. The young author, Albert von Bezold*, analyzed the bodies of small animals for water, solids, and ash1, and announced as a result of his findings a fundamental concept in regard to tissue composition, namely, that animals possess water, organic matter, and ash contents which are characteristic of species and age. He found that growth was accompanied by a decrease in percentage of water and an increase in ash; and further that these changes occurred more rapidly in the early phases of the growth process. Similar trends in composition were predicted for man.

Rapid and coupled phenotypic and genetic divergence in Icelandic Arctic char (Salvelinus alpinus)

1999 ◽  
Vol 56 (12) ◽  
pp. 2229-2234 ◽  
Author(s):  
Davíð Gíslason ◽  
Moira M Ferguson ◽  
Skúli Skúlason ◽  
Sigurður S Snorrason
Keyword(s):  
Genetic Divergence ◽  
Driving Force ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Variable Degree ◽  
Morphological Divergence ◽  
Resource Polymorphism ◽  
Trophic Diversification ◽  
Early Phases ◽  
Different Levels

Resource polymorphism has been proposed as an important phase of diversification and speciation in vertebrates. Studies of fish in young lakes of the Northern Hemisphere indicate variably advanced cases of adaptive trophic diversification. We have previously proposed a scheme describing this variation in terms of a gradient of resource-based polymorphic traits, emphasizing flexible behaviour in early phases and morphological divergence in more advanced phases. Here, we present data on Arctic char (Salvelinus alpinus) in Icelandic lakes exhibiting a variable degree of phenotypic and genotypic segregation. We show that (i) the morphs are at different levels of phenotypic segregation and reproductive isolation and in one case completely reproductively isolated, (ii) morphs within lakes appear to be of intralacustrine origin, and (iii) the morphological and genetic divergence of morphs is correlated, suggesting a role for trophic adaptation as a driving force in morph segregation.

Sign in / Sign up

Export Citation Format

Share Document