Accurate Determination of the Cold Detection Threshold with High-Speed Cooling of the Skin

Pain Medicine ◽  
2020 ◽  
Vol 21 (12) ◽  
pp. 3428-3436
Author(s):  
Segolene Lithfous ◽  
Olivier Després ◽  
Thierry Pebayle ◽  
Claudia Casadio ◽  
Andre Dufour
Keyword(s):  
High Speed ◽  
Accurate Determination ◽  
Detection Threshold ◽  
Detection Thresholds ◽  
Temperature Ramp ◽  
Temperature Ramps ◽  
The Subject ◽  
Order Four ◽  
Healthy Participants

Abstract Objective This study used high-speed cooling of the skin and exact control of stimulus duration to measure the cold detection threshold in healthy participants. The objective was to compare the method of limits, in which the temperature is slowly and gradually increased/decreased until the subject perceives the stimulation, and the method of levels, in which the subject must detect brief thermal stimulations close to the threshold of perception. Methods Twenty healthy volunteers (nine women, 11 men) aged 20–30 years participated in the study. The method of limits and method of levels were performed in all subjects in a counterbalanced order. Four cold detection thresholds were measured with the method of levels, with a temperature ramp of 300°C/sec and stimulus durations of 50 ms, 100 ms, 300 ms, and 500 ms. Three thresholds were measured with the method of limits, with temperature ramps of 1°C/sec, 2°C/sec, and 4°C/sec. Results On average, the cold detection thresholds were −0.47°C below skin temperature with the method of levels and −1.67°C the method of limits. Interindividual variability was significantly lower with the method of levels than with the method of limits. Conclusions These results suggest that the method of levels is more accurate than the method of limits for measuring cold detection threshold. The improvement of cold detection threshold measurement may provide new perspectives to more precisely assess the function of A-delta fibers and the spino-thalamic pathway.

scholarly journals Is Peripheral Motion Detection Affected by Myopia?

2021 ◽  
Vol 15 ◽  
Author(s):  
Junhan Wei ◽  
Deying Kong ◽  
Xi Yu ◽  
Lili Wei ◽  
Yue Xiong ◽  
...  
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Motion Detection ◽  
High Speed ◽  
Detection Threshold ◽  
High Spatial Frequency ◽  
Spherical Equivalent ◽  
Detection Thresholds ◽  
Significant Difference ◽  
Motion Speed

PurposeThe current study was to investigate whether myopia affected peripheral motion detection and whether the potential effect interacted with spatial frequency, motion speed, or eccentricity.MethodsSeventeen young adults aged 22–26 years participated in the study. They were six low to medium myopes [spherical equivalent refractions −1.0 to −5.0 D (diopter)], five high myopes (<-5.5 D) and six emmetropes (+0.5 to −0.5 D). All myopes were corrected by self-prepared, habitual soft contact lenses. A four-alternative forced-choice task in which the subject was to determine the location of the phase-shifting Gabor from the four quadrants (superior, inferior, nasal, and temporal) of the visual field, was employed. The experiment was blocked by eccentricity (20° and 27°), spatial frequency (0.6, 1.2, 2.4, and 4.0 cycles per degree (c/d) for 20° eccentricity, and 0.6, 1.2, 2.0, and 3.2 c/d for 27° eccentricity), as well as the motion speed [2 and 6 degree per second (d/s)].ResultsMixed-model analysis of variances showed no significant difference in the thresholds of peripheral motion detection between three refractive groups at either 20° (F[2,14] = 0.145, p = 0.866) or 27° (F[2,14] = 0.475, p = 0.632). At 20°, lower motion detection thresholds were associated with higher myopia (p < 0.05) mostly for low spatial frequency and high-speed targets in the nasal and superior quadrants, and for high spatial frequency and high-speed targets in the temporal quadrant in myopic viewers. Whereas at 27°, no significant correlation was found between the spherical equivalent and the peripheral motion detection threshold under all conditions (all p > 0.1). Spatial frequency, speed, and quadrant of the visual field all showed significant effect on the peripheral motion detection threshold.ConclusionThere was no significant difference between the three refractive groups in peripheral motion detection. However, lower motion detection thresholds were associated with higher myopia, mostly for low spatial frequency targets, at 20° in myopic viewers.

Factors affecting the accurate determination of cerebrovascular blood flow using high-speed droplet imaging

1998 ◽  
Author(s):  
Stephen Rudin ◽  
Afshin Divani ◽  
Ajay K. Wakhloo ◽  
Baruch B. Lieber ◽  
William Granger ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Accurate Determination ◽  
Factors Affecting

An Experimental Study of the Stability of an Externally Pressurized, Gas-Lubricated Thrust Bearing

1966 ◽  
Vol 33 (1) ◽  
pp. 25-30 ◽  
Author(s):  
L. Licht ◽  
H. G. Elrod
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Thrust Bearing ◽  
Accurate Determination ◽  
Experimental Program ◽  
The Subject ◽  
The Stability ◽  
Stability Limits ◽  
Prior Analysis

The subject of this experimental investigation is the phenomenon of self-excited vibrations occurring in externally pressurized, gas-lubricated bearings. The experimental program pursued here is guided by predictions based on prior analysis. An apparatus is designed and instrumented to provide for the variation of governing parameters and for the accurate determination of their critical values. Stability bounds are obtained for a circular thrust bearing and the experimental results are compared and contrasted with previously reported, theoretical stability limits.

scholarly journals New high-speed centre of mass method incorporating background subtraction for accurate determination of fluorescence lifetime

2016 ◽  
Vol 24 (7) ◽  
pp. 6899 ◽  
Author(s):  
Simon P. Poland ◽  
Ahmet T. Erdogan ◽  
Nikola Krstajić ◽  
James Levitt ◽  
Viviane Devauges ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Background Subtraction ◽  
High Speed ◽  
Accurate Determination ◽  
Centre Of Mass

Experimental device for the accurate determination of wood-water relations on micro-samples

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 419-429 ◽  
Author(s):  
Patrick Perré
Keyword(s):  
Moisture Content ◽  
Water Relations ◽  
High Speed ◽  
Growth Ring ◽  
Accurate Determination ◽  
Longitudinal Direction ◽  
Experimental Device ◽  
Normal Wood ◽  
Diamond Wire Saw

Abstract This paper describes an experimental device designed for the accurate determination of wood/water relations on micro-samples. The moisture content of the sample is measured with a highly sensitive electronic microbalance. Moreover, the dimensions of the sample in tangential and longitudinal direction are collected continuously without contact by means of two high-speed laser scan micrometers. The device is placed in a climatic chamber. The micro-samples investigated were prepared with a diamond wire saw. A sample thickness of less than 1 mm allows the moisture content to be almost uniform during the test. The data obtained are of excellent quality and accuracy, in spite of the very small mass and dimensions of the samples. The device provides a perfect tool for investigating the dynamic interaction between relative humidity, moisture content, and shrinkage. Results collected for beech, spruce and eucalyptus are presented. Important findings include: deviation from a linear relation between shrinkage and moisture content in beech; uniqueness of the shrinkage versus moisture content curve during desorption/adsorption cycles; evidence of cell collapse in eucalyptus, especially for tension wood; and property variations within the growth ring of normal wood and compression wood of spruce.

Comparison of Two ELISA Screening Tests with Liquid Chromatography for Determination of Aflatoxins in Raw Peanuts

1989 ◽  
Vol 72 (6) ◽  
pp. 962-964
Author(s):  
Joe W Dorner ◽  
Richard J Cole
Keyword(s):  
Liquid Chromatography ◽  
Detection Threshold ◽  
Screening Tests ◽  
Rapid Screening ◽  
Detection Thresholds ◽  
Immunosorbent Assays ◽  
Card Test

Abstract A study was conducted to evaluate the performance of 2 enzymelinked immunosorbent assays (ELISA) for rapidly screening samples of peanuts for the presence of aflatoxin. The EZ-Screen Quick Card Test and the Afla-10 Cup Test were compared with liquid chromatography in duplicate analyses of common extracts of peanuts contaminated in the range of 0-70 ppb (ng/g). Each assay properly identified 95% of samples containing no detectable aflatoxin as negative and >97% of samples containing >10 ppb aflatoxin as positive. The card test, which had a 20 ppb detection threshold, identified as positive 32 of 34 samples in the 11-20 ppb range. This indicates that the card test might actually have a detection threshold closer to 10 ppb. Most of the errors associated with the assays occurred on samples containing <10 ppb aflatoxin. The cup and card tests identified 76 and 67% of the samples, respectively, as negative, in the range of 4-10 ppb. For samples either negative or contaminated above their detection thresholds for the assays, the methods are well suited for use as rapid screening tests.

scholarly journals Determination of digesta flow entering the omasal canal of dairy cows using different marker systems

2003 ◽  
Vol 90 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Seppo Ahvenjärvi ◽  
Aila Vanhatalo ◽  
Kevin J. Shingfield ◽  
Pekka Huhtanen
Keyword(s):  
Particulate Matter ◽  
Liquid Phase ◽  
Dairy Cows ◽  
High Speed ◽  
Volatile Fatty Acids ◽  
Accurate Determination ◽  
Water Soluble ◽  
Neutral Detergent Fibre ◽  
Inorganic Matter

Four studies were conducted to compare the effect of four indigestible markers (LiCoEDTA, Yb-acetate, Cr-mordanted straw and indigestible neutral-detergent fibre (INDF)) and three marker systems on the flow of digesta entering the omasal canal of lactating dairy cows. Samples of digesta aspirated from the omasal canal were pooled and separated using filtration and high-speed centrifugation into three fractions defined as the liquid phase, small particulate and large particulate matter. Co was primarily associated with the liquid phase, Yb was concentrated in small particulate matter, whilst Cr and INDF were associated with large particles. Digesta flow was calculated based on single markers or using the reconstitution system based on combinations of two (Co + Yb, Co + Cr and Co + INDF) or three markers (Co + Yb + Cr and Co + Yb + INDF). Use of single markers resulted in large differences between estimates of organic matter (OM) flow entering the omasal canal suggesting that samples were not representative of true digesta. Digesta appeared to consist of at least three phases that tended to separate during sampling. OM was concentrated in particulate matter, whilst the liquid phase consisted mainly of volatile fatty acids and inorganic matter. Yb was intimately associated with nitrogenous compounds, whereas Cr and INDF were concentrated in fibrous material. Current data indicated that marker systems based on Yb in combination with Cr or INDF are required for the accurate determination of OM, N and neutral-detergent fibre flow. In cases where the flow of water-soluble nutrients entering the omasal canal is also required, the marker system should also include Co.

On the variation of the electromotive force of different forms of the Clark standard cell with temperature and with strength of solution

1898 ◽  
Vol 62 (379-387) ◽  
pp. 117-152 ◽  
Keyword(s):  
Electromotive Force ◽  
Accurate Determination ◽  
Scientific Paper ◽  
Standard Cells ◽  
Temperature Coefficients ◽  
Primary Object ◽  
Mcgill University ◽  
Series Of Experiments ◽  
The Subject

The primary object of the present series of experiments was that of equipping the McDonald Physics Building of McGill University with a reliable and accurate set of standard cells, and not that of forming the subject of a communication to any scientific paper. In the course of the work, however, several points have come under our notice, which we venture to think may be of interest to others engaged in any investigation requiring the employment or construction of such standards. Among other points, we have devoted special attention to the accurate determination of the temperature-coefficients of various forms of Clark cell; to the construction of cells free from “diffusion-lag” consequent upon change of temperature; and to the investigation of the limits of accuracy attainable with Clark cells under both constant and varying temperature conditions.

Crystal orientation effects in the x-ray microanalysis of spinels

1992 ◽  
Vol 50 (2) ◽  
pp. 1240-1241
Author(s):  
Ian M. Anderson
Keyword(s):  
Crystal Orientation ◽  
Spinel Phase ◽  
Accurate Determination ◽  
Test Case ◽  
Second Phase ◽  
X Ray ◽  
Impurity Atoms ◽  
Electron Intensity ◽  
The Subject

Compounds with the crystal structure of the mineral spinel (MgAl2O4) provide an interesting test case for the quantitative x-ray microanalysis of crystals. The cations occupy more than one crystallographic site, two thirds occupying the octahedral 16d interstices and one third occupying the tetrahedral 8a interstices of the oxygen anion sublattice (Fd3m). Under dynamical electron diffraction conditions in the AEM, the standing-wave electron intensity on the two sublattices may differ considerably, in turn yielding proportionally different x-ray count rates from the cations on these sublattices. This effect has been exploited to determine the sites of impurity atoms in spinels using the ALCHEMI technique. The strong crystal orientation effect obstructs the accurate determination of the composition of spinels using x-ray microanalysis, however. In the system NiO-TiO2, which is the subject of ongoing investigation, a second phase is always found finely dispersed within the metastable spinel phase. The AEM is the only instrument which provides the high spatial resolution necessary to probe the composition.

scholarly journals Implementation of the AHP Method for Determining the Weights of Factors Decisive for the Location of the Municipal Waste Conversion Plant, on the Example of the City of Krakow

2017 ◽  
Vol 20 (1) ◽  
pp. 19-23
Author(s):  
Monika Siejka ◽  
Monika Mika
Keyword(s):  
Accurate Determination ◽  
Waste Incineration ◽  
Optimal Choice ◽  
Municipal Waste ◽  
Analytical Hierarchical Process ◽  
Incineration Plant ◽  
The Subject ◽  
The City ◽  
Municipal Waste Incineration

AbstractThe paper proposes a methodology for calculating the weights of factors determining the choice of location of municipal waste incineration plant (MWIP). Objective and accurate determination of the weights offers the optimal choice of location. To achieve the planned purpose, the method of the analytical hierarchical process was applied. The study included seven potential locations for the municipal waste incineration plant, located within the area of the city of Krakow. The objective of the analysis, which is the subject of this publication, is determination of weights of factors decisive for the choice of MWIP location. These weights were calculated using the method of the analytical hierarchical process. The choice of the method is dictated by the fact that in the studied case we deal with multivariate analysis, and its components are described both in quantitative and qualitative ways.

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