Determination of short-lived radionuclides in neutron-activated human head-hair samples

Young's modulus of 12 samples of human scalp hair, representing both sexes, has been determined to find out whether this physical characteristic could be used in the determination of sex, age or identity of a person. Hair samples of an individual were tested before as well as after washing and drying by ‘Constant Rate of Loading’ (CRL) method. Results indicate that washing and drying have some influence on the Young's modulus of human head hair. On washing and drying, the values of this parameter for both male and female hair are found to increase, but statistically the difference is insignificant. The Young's modulus values appear to be of little value in determining the sex of an individual. For differentiating between individuals also, due to large variation in the random values of hair of the same scalp, this property appears to be useful only for purposes of elimination in certain circumstances, particularly if hair is found in some fair quantity, and not for positive identification.

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Evaluating Endogenous GHB Variation in Hair with a Synthetic Hair Matrix

Journal of Analytical Toxicology ◽

10.1093/jat/bkz095 ◽

2020 ◽

Vol 44 (4) ◽

pp. 354-361 ◽

Cited By ~ 2

Author(s):

Erin W Lloyd ◽

Jennifer L Thomas ◽

Christopher C Donnelly ◽

Madeline A Montgomery ◽

Roman P Karas ◽

...

Keyword(s):

Limit Of Detection ◽

Human Head ◽

Calibration Model ◽

Head Hair ◽

Drug Concentrations ◽

Hair Samples ◽

Limit Of Quantitation ◽

Hair Matrix ◽

Liquid Chromatography Tandem Mass ◽

Multiple Donors

Abstract The variation in drug concentrations in human head hair from 22 donors was measured using a synthetic hair matrix (SMx™ hair). This matrix is being reported for the first time as a calibrator for an endogenous substance. In comparison to authentic hair or melanin, the synthetic hair provided a reliable batch-to-batch source of liquid matrix similar in composition to authentic hair, but without detectable concentrations of endogenous gamma-hydroxybutyric acid (GHB). Using the synthetic matrix for calibrator samples, validation of a liquid chromatography–tandem mass spectrometry (LC-MS/MS) quantitative method for GHB in human head hair was completed. Validation included the evaluation of the following parameters: accuracy, precision, calibration model, carryover, interferences, limit of detection (LOD), limit of quantitation (LOQ) and processed sample stability. The method was valid over a range of 0.4–12 ng/mg, and its LOD and LOQ were both experimentally estimated to be 0.4 ng/mg. After validation, the variation in endogenous GHB concentrations across multiple donors and locations in the vertex posterior region of the human head were evaluated. Results for 11 non-GHB users showed minimal variability (average 3.0% RSD) across the vertex posterior for hair samples taken from three different areas. There was also low variability (average 1.8% RSD) in repeat samples taken from the same location for 11 other non-users. Endogenous GHB concentrations from the LOD/LOQ to 5.60 ng/mg were determined for the 22 donors using the synthetic hair as a calibrator. These results demonstrate the successful application of a synthetic hair matrix in the analysis of GHB in human hair.

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Gender determination of caucasoid hair using image analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146928 ◽

1993 ◽

Vol 51 ◽

pp. 216-217

Author(s):

T.B. Ball ◽

W.M. Hess

Keyword(s):

Image Analysis ◽

Cross Sections ◽

Scalp Hair ◽

The Body ◽

Equivalent Diameter ◽

Cross Sectional ◽

Hair Samples ◽

Length Width ◽

Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

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