Hair Dye Penetration in Monkeys and Human Beings

2021 ◽  
pp. 397-416
Author(s):  
Nadia Kashetsky ◽  
Rebecca M. Law ◽  
Leszek J. Wolfram ◽  
Howard I. Maibach
2021 ◽  
Vol 12 (3) ◽  
pp. 645-648
Author(s):  
Mrudula Vinayak Joshi ◽  
Joshi Vinayak Nilkanth ◽  
Shital Rahul Rasane

Introduction: Colour of hair is most conspicuous phenotype of human beings and plays an important role in one's overall physical beauty. Premature hair greying (PHG) has caused the increased use of various hair dyes in population though it has adverse effects. Aim- To assess knowledge, practice of hair dye users with purpose, frequency of use and adverse reactions if any on hair, scalp, skin. Methodology: A cross-sectional study was conducted on participants from PCMC region by interview method using a questionnaire (20 questions) specially prepared pertaining to use of hair dye and adverse reactions to it. Statistical Analysis-The demographic data is expressed as mean ± standard deviation, quantitative data expressed as percentages. Results: A total 98subjects including 75.5% and 24.5% females and males respectively. The participants started using hair dye at an age of 25 (±3.03) years. Herbal and Synthetic dyes were used by 36.74% and 63.27% respectively. Frequency of use in a year was 4-5 times in 58.16%.  Adverse reactions of dye on body of hair like dryness46.94%, loss of hair 30.62%, change in texture and thinning were reported. 29.59% of subjects showed ill effects during dyeing of scalp while in 68.36% of subjects after the dyeing process was complete. Conclusion: Majority Population started hair dyeing at very early age using Chemical dyes even though they perceived herbal dyes were safe. They continued hair colouring despite adverse reactions, which indicates aesthetic importance of hair colour and need of research in the field of Ayurveda for developing safe, natural hair dye.


2021 ◽  
Author(s):  
Anbalagan Sriniva ◽  
Rajagopal Mayildurai ◽  
Thiyagarajan Maruthavanan ◽  
Alagunambi Ramasubbu

Abstract The volatile organic compounds (VOCs) in cosmetics pose a series threat to the environment and their exposure causes a variety of ailments in human beings. The present work analyses systematically the presence of VOCs in samples of cosmetic products available in open market such as, aftershave lotion, face cream, hair dye, lipsticks, perfumes, shampoos and talcum powders by GC–MS. The investigation revealed the prevalence of more than 158 hazardous volatile organic compounds (VOCs) out of 243 organic compounds in 20 samples of the cosmetic products. The detected VOCs fall into six major groups viz., alcohols, esters, ethers, carboxylic acids and amides. Among all the VOCs detected, diethyl phthalate is found to be present in majority of the samples, which could cause mild eye and skin irritations and affect the central nervous system depending on the dosage. The samples were also found to contain certain fatty acid methyl esters. The study suggests proper instructions on the labels of such products to warn the customers. Further, finding non-toxic alternatives to existing additives has also been emphasized.


1954 ◽  
Vol 27 (5) ◽  
pp. 565-577 ◽  
Author(s):  
John F. Scholer ◽  
Charles F. Code

1949 ◽  
Vol 12 (6) ◽  
pp. 970-977 ◽  
Author(s):  
John M. McMahon ◽  
Charles F. Code ◽  
Willtam G. Saver ◽  
J. Arnold Bargen
Keyword(s):  

Author(s):  
Charles A. Doan ◽  
Ronaldo Vigo

Abstract. Several empirical investigations have explored whether observers prefer to sort sets of multidimensional stimuli into groups by employing one-dimensional or family-resemblance strategies. Although one-dimensional sorting strategies have been the prevalent finding for these unsupervised classification paradigms, several researchers have provided evidence that the choice of strategy may depend on the particular demands of the task. To account for this disparity, we propose that observers extract relational patterns from stimulus sets that facilitate the development of optimal classification strategies for relegating category membership. We conducted a novel constrained categorization experiment to empirically test this hypothesis by instructing participants to either add or remove objects from presented categorical stimuli. We employed generalized representational information theory (GRIT; Vigo, 2011b , 2013a , 2014 ) and its associated formal models to predict and explain how human beings chose to modify these categorical stimuli. Additionally, we compared model performance to predictions made by a leading prototypicality measure in the literature.


2015 ◽  
Vol 223 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Nina Schweinfurth ◽  
Undine E. Lang

Abstract. In the development of new psychiatric drugs and the exploration of their efficacy, behavioral testing in mice has always shown to be an inevitable procedure. By studying the behavior of mice, diverse pathophysiological processes leading to depression, anxiety, and sickness behavior have been revealed. Moreover, laboratory research in animals increased at least the knowledge about the involvement of a multitude of genes in anxiety and depression. However, multiple new possibilities to study human behavior have been developed recently and improved and enable a direct acquisition of human epigenetic, imaging, and neurotransmission data on psychiatric pathologies. In human beings, the high influence of environmental and resilience factors gained scientific importance during the last years as the search for key genes in the development of affective and anxiety disorders has not been successful. However, environmental influences in human beings themselves might be better understood and controllable than in mice, where environmental influences might be as complex and subtle. The increasing possibilities in clinical research and the knowledge about the complexity of environmental influences and interferences in animal trials, which had been underestimated yet, question more and more to what extent findings from laboratory animal research translate to human conditions. However, new developments in behavioral testing of mice involve the animals’ welfare and show that housing conditions of laboratory mice can be markedly improved without affecting the standardization of results.


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