The surface and internal features of pubic hair: A comparative study with those of scalp hair.

Although pubic hair has been a subject of public interest, little is known about its structure or characteristics beyond its curly and coarse appearance. In this study, we investigated the surface and internal features of pubic hair from Korean males and compared them to those of scalp hair from the same donors. Our findings indicate that the cuticle layer of pubic hair has a greater number of scales than that of scalp hair, resulting in a thicker cuticle layer overall. Fourier-transform infrared (FT-IR) spectroscopy analysis showed that the protein in the cortex layer of pubic hair was less affected by exposure to urine or ammonia than the protein in the cortex layer of scalp hair. This suggests that the cuticle layer of pubic hair, which is thicker and composed of more scales, acts as a physical barrier that protects the hair's internal structure. Furthermore, we observed that the secondary and tertiary structures of keratin in the pubic hair cuticle layer are essentially different from those in scalp hair. Based on these findings, we hypothesize that the thickened cuticle layer in pubic hair may have evolved as a defence mechanism against chemical damage from urine, urea and ammonia.

Distribution of bacterial community structures on human scalp hair shaft in relation to scalp sites.

Bacterial community structure on the human skin is specific to each individual and varies among different body sites. In this study, we investigated differences in bacterial community structure among 5 hair sampling sites and among 12 individuals. Significant differences were found between individuals in terms of alpha diversity and relative abundance of major bacterial phyla and genera, whereas no differences were found between hair sampling sites. The principal coordinate analysis plots of within-individual group tended to converge individually, whereas those of within-hair sampling site group did not cluster. In addition, weighted UniFrac analysis showed that the individual-based category was a statistically significant category but not the scalp hair sampling site-based category. These results suggest that the distribution of bacterial community structures on scalp hair shafts within individuals was relatively steady, even when the scalp hair sampling site was different.

Levels of trace elements in human hair samples of adolescents living near petrochemical plants.

The aim of the study is a comparative analysis to investigate human hair metal profiles of adolescents residing near petrochemical plants (Sicily, Italy). We selected the small town of Augusta, Gela, and Pace del Mela, and a control area made up of the towns characterized by low anthropogenic activity. Twenty trace elements were measured in samples of scalp hair from adolescents (11-14 years old) of both genders. Hair samples were cleaned using a rigorous cleaning method, mineralized, and processed for analyses by inductively coupled plasma-mass spectrometry (ICP-MS). In industrial sites, zinc was always the most abundant element, ranging from186 to 217 µg g-1. Following zinc, the elements Al, Ba, Cu, Fe, and Sr were in the range 1-20 µg g-1. The remaining elements had concentrations < 1 µg g-1. The comparison with adolescents living in suburban area highlighted that As, Ba, Mn, Sr, U, and V have the highest median concentrations in an industrial location. An industrial factor (As, Mn, Sr, U, and V) and an urban factor (Cd, Cr, Cu, Mo, Ni, and Sb) were distinguished by the multivariate statistical analysis between a cohort residing in urban and industrial areas. Statistically significant differences (Kruskal-Wallis test, p < 0.05) between the genders were found for Ba, Mn, Ni, Sr, and V in all industrial sites with median concentrations higher in females' hair than males'. The data confirm that the study areas are heavily affected by industrial and urban emissions of metals and metalloids, representing a potential hazard to the local population.

Further delineation of putative ACTB loss-of-function variants: A 4-patient series.

ACTB encodes ß-cytoplasmic actin, an essential component of the cytoskeleton. Based on chromosome 7p22.1 deletions that include the ACTB locus and on rare truncating ACTB variants, a phenotype resulting from ACTB haploinsufficiency was recently proposed. We report putative ACTB loss-of-function variants in four patients. To the best of our knowledge, we report the first 7p22.1 microdeletion confined to ACTB and the second ACTB frameshifting mutation that predicts mRNA decay. A de-novo ACTB p.(Gly302Ala) mutation affects ß-cytoplasmic actin distribution. All four patients share a facial gestalt that is distinct from that of individuals with dominant-negative ACTB variants in Baraitser-Winter cerebrofrontofacial syndrome. Two of our patients had strikingly thin and sparse scalp hair. One patient had sagittal craniosynostosis and hypospadias. All three affected male children have attention deficits and mild global developmental delay. Mild intellectual disability was present in only one patient. Heterozygous ACTB deletion can allow for normal psychomotor function.

Relationship between the bacterial community structures on human hair and scalp.

In this study, we investigated and compared characteristics of the bacterial community structures on hair (scalp hair) and scalp in 18 individuals. Significant differences were found between the sites, in terms of cell density, alpha and beta diversity, and relative abundance of the phyla, Firmicutes and Proteobacteria, whereas no difference was found in relative abundance of the phylum Actinobacteria. Bacteria of the genus Cutibacterium showed similar relative abundance at both sites, whereas those of genus Pseudomonas were highly abundant on hair, and those of genus Staphylococcus were significantly lesser in abundance on hair than on scalp. Statistical correlations between the sites were high for the individual relative abundance of five major operational taxonomic units (OTUs). This suggests that the bacterial community structure on hair is composed of hair-specific genus, Pseudomonas, and skin-derived genera, Cutibacterium and Staphylococcus, and is distinguishable from other human skin microbiomes.

Chemical Markers for Short- and Long-Term Areca Nut Exposure.

Background: Areca nut (AN) chewing causes oral cancer. AN cessation programs are the most effective approach to reduce AN chewing induced cancers but require biomarkers to determine program compliance and success. Objectives: To explore chemical markers for short- and long-term AN exposure using non-invasively collected saliva, buccal cells (BCs), and scalp hair of chewers. Methods: Saliva was collected from a male chewer before and up to 2 days after AN chewing. Saliva was separated into supernatant and pellet (BCs) then analyzed by spectrophotometry and liquid chromatography (LC) with UV/VIS detection. Scalp hair was collected from four chewers and analyzed for areca alkaloids using direct analysis in real time-tandem mass spectrometry (DART-MSMS). Results: The red pigmented saliva after chewing showed no valuable signals when either the saliva supernatant or pellet (BCs) were analyzed by spectrophotometry. Saliva analysis by LC-UV/VIS showed diagnostically valuable signals at 488 nm up to 5 and 24 h post chewing in the supernatant and pellet, respectively. DART-MSMS analysis detected two of the four AN specific alkaloids (arecoline and arecaidine) in male but none in female hair. Conclusions/Importance: LC-UV/VIS analysis of the red pigments extracted from saliva and BCs after AN chewing showed distinct signals up to 24 h post chewing while DART-MSMS analysis in BCs and scalp hair showed selective signals of AN alkaloids for several weeks or months after AN exposure. Chemical hair treatment might prevent detection of areca alkaloids in hair. AN cessation trials and other programs now have essential tools for bioverification.

Revealing details of stays abroad by sequential stable isotope analyses along human hair strands.

Multi-element stable isotope analyses of δ13C, δ15N, δ34S and δ2H values were performed along scalp hair strands to detect isotopic changes resulting from different stays abroad. One hair strand with a hair length of more than 50 cm originated from a German woman, who frequently made long-distance travels of 1 to 4 weeks. The second hair strand with a length of 15 cm was taken from a Japanese woman who went to Germany for a period of some months. Stable isotopic influences due to the stays abroad were clearly reflected in the 5-mm segments along the proximal part of the hair strand; whereas in the more distal parts, the isotopic influences were blurred. This can be regarded as the result of the highly variable intra-individual hair growth rate of single hairs of at least ± 30% compared to the mean growth rate. Consequently, the initial isotope signal obtained by short stays abroad became rapidly attenuated in the more distal parts of the hair strand. Furthermore, decreasing sulphur content associated with higher sulphur isotope values was observed with increasing hair length. The isotope shifts along the scalp hair strand, provoked by dietary changes at new locations, appeared at such points of hair length, which correspond well with the maximum growth rate of single hairs. Consequently, the exact date for any changes coming along with isotopic shifts may be calculated by best approach considering a hair growth value of 1.4 cm per 30 days, instead of the commonly used mean monthly hair growth rate of 1.1 cm. This may be important in forensics, if detailed information about a person's recent lifetime should be figured out by segmental scalp hair analyses.

Distribution characteristics and influencing factors of heavy metals in scalp hair of Huainan urban residents.

In order to explore the level of heavy metal pollution in human hair of residents in Huainan City and provide theoretical guidance for prevention and control of heavy metal pollution, human hair samples from 174 residents in Huainan City were collected so that heavy metal (Cr, Cu, Pb, Zn, As, and Fe) concentrations in scalp hair could be tested, and meanwhile their relationship with sex, age, and spatial distribution characteristics could be explored as well. According to the final analysis, the average concentration of Cr, Pb, Cu, Fe, Zn, and As in human hair amounted to 1.56, 6.41, 14.96, 31.13, 166.54, and 1.07 mg/kg. The highest average of Cr and Pb contents in human hair occurred in the area of Xiejiaji District; Fe, Zn, and Hg were in Datong District; and Cu and As were in Panji District respectively. Overall, the lowest risk of heavy metal exposure existed in Tianjia'an District. Heavy metal content in hair varied across sexes and ages. Pb concentration in hair would decrease as age increased. The highest Pb concentration appeared in children between ages 0 and 10, the amount of which was significantly different from that in other age groups; hence, children appear to be more susceptible to Pb pollution than other ages. Contents of Cr, Fe, Zn, and As in hair would also increase with age; Fe content in hair was particularly correlated with age. The contents of Cr, Pb, Fe, and As in men's hair were higher than those in women's, whereas the case of Cu and Zn was just the opposite. There were significant differences between sexes concerning the contents of Cr, Cu, and As, and a highly significant difference about Zn between sexes as well. These results indicated that the contents of heavy metal in residents' hair would be closely related to the features of the local environment and population.

Essential and Non-essential Elements in Scalp Hair of Diabetics: Correlations with Glycated Hemoglobin (HbA1c).

Essential elements (Ca, Mg, Zn, Cu, Fe, Cr, Mn and V) and non-essential elements (As, Cd, Hg and Pb) were measured in scalp hair samples of 45 diabetic subjects and 59 control subjects in Japan using inductively coupled plasma mass spectrometry. All diabetic subjects took insulin and/or antidiabetic agents, with glycated hemoglobin (HbA1c) ranging between 6.2 and 14.4%. The levels of Zn, Cu and Cr in the diabetic subjects (HbA1c>7) were significantly lower than those in the control subjects (p<0.05), and these concentrations decreased significantly with increases in HbA1c (p<0.01). The levels of Fe and Mg in the diabetic subjects were insignificantly lower, and the concentration of Fe decreased significantly with increases in HbA1c (p<0.05) and the concentration of Mn tended to decrease (p<0.10). In contrast, the concentration of As tended to increase with increases in HbA1c (p<0.10). The concentrations of other elements, such as Ca, Mn, V, Pb, Cd and Hg, in the diabetic subjects were similar to those of control subjects, and did not correlate with HbA1c. The average of estimated glomerular filtration rate (eGFR) in the diabetic subjects was 77.7±29.7 mL/min/1.73 m2 with large variation (12.7-148 mL/min/1.73 m2), and previous study reported the increase of urinary excretion of Zn, Cr, Mn and Mg in diabetic subjects. The decreases of Zn, Cu, Cr, Fe and Mg concentrations in hair may reflect increased urinary excretion of these elements due to diabetic nephropathy.

Evaluation of scalp hair nickel and chromium level changes in patients with fixed orthodontic appliance: a one-year follow-up study.

BACKGROUND AND OBJECTIVES: The release of metal ions from orthodontic appliances is part of the dissolution and biomechanical processes of alloys. Nickel (Ni) and chromium (Cr) are the elements commonly used in the manufacture of various components of fixed orthodontic appliances, including bands, brackets and wires. This study was aimed to measure the Ni and Cr ions levels in the scalp hair of patients treated with fixed orthodontic appliances in comparison of the control group. MATERIALS AND METHODS: The patient group consisted of 24 patients treated with fixed orthodontic appliances for one year, while the control group included 28 healthy individuals without orthodontic appliances. Analysis of the Cr and Ni was performed using atomic absorption spectrophotometer by graphite furnace method. The data were analyzed via student and paired samples t-test and ANOVA repeated measurement test. RESULTS: After one year, the levels of Ni and Cr in two groups showed significant differences (0.086 ± 0.007 and 0.258 ± 0.009 µg/g for control group and 0.149 ± 0.010 and 0.339 ± 0.013 µg/g for patient group, respectively for Ni and Cr, p < .001). ANCOVA test by removing the effects of age, gender and the baseline levels of Ni and Cr showed that changes in these ions in the scalp hair of both groups after one year were statistically significant. CONCLUSION: Due to the slightly elevated levels of Ni and Cr ions in the scalp hair of patients treated with fixed orthodontic appliances and considering the cytotoxic and allergic effects of these ions, changing the ingredients in fixed orthodontic appliances is suggested for the future.

Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China.

The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 µg (kg bw)-1 day-1 of Cu, 288 µg (kg bw)-1 day-1 of Zn, 2.01 µg (kg bw)-1 day-1 of Pb, 0.41 µg (kg bw)-1 day-1 of Cd, 0.01 µg (kg bw)-1 day-1 of Hg, and 0.52 µg (kg bw)-1 day-1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 µg (kg bw)-1 day-1 and 1.68 µg (kg bw)-1 day-1, respectively, which are above the recommended levels [i.e., 3.58 µg (kg bw)-1 day-1 for Pb and 1.0 µg (kg bw)-1 day-1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg-1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.

Correlation of lithium levels between drinking water obtained from different sources and scalp hair samples of adult male subjects.

There is some evidence that natural levels of lithium (Li) in drinking water may have a protective effect on neurological health. In present study, we evaluate the Li levels in drinking water of different origin and bottled mineral water. To evaluate the association between lithium levels in drinking water with human health, the scalp hair samples of male subjects (25-45 years) consumed drinking water obtained from ground water (GW), municipal treated water (MTW) and bottled mineral water (BMW) from rural and urban areas of Sindh, Pakistan were selected. The water samples were pre-concentrated five to tenfold at 60 °C using temperature-controlled electric hot plate. While scalp hair samples were oxidized by acid in a microwave oven, prior to determined by flame atomic absorption spectrometry. The Li content in different types of drinking water, GW, MTW and BMW was found in the range of 5.12-22.6, 4.2-16.7 and 0.0-16.3 µg/L, respectively. It was observed that Li concentration in the scalp hair samples of adult males consuming ground water was found to be higher, ranged as 292-393 µg/kg, than those who are drinking municipal treated and bottle mineral water (212-268 and 145-208 µg/kg), respectively.

Distribution and health risk assessment to heavy metals near smelting and mining areas of Hezhang, China.

Mining and smelting areas in Hezhang have generated a large amount of heavy metals into the environment. For that cause, an evaluative study on human exposure to heavy metals including Co, Ni, Cu, Zn, Cr, As, Cd, Pb, Sb, Bi, Be, and Hg in hair and urine was conducted for their concentrations and correlations. Daily exposure and non-carcinogenic and carcinogenic risk were estimated. Sixty-eight scalp hair and 66 urine samples were taken from participants of different ages (6-17, 18-40, 41-60, and ≥ 65 years) living in the vicinity of an agricultural soil near mine and smelting areas. The results compared to the earlier studies showed an elevated concentration of Pb, Be, Bi, Co, Cr, Ni, Sb, and Zn in hair and urine. These heavy metals were more elevated in mining than in smelting. Considering gender differences, females were likely to be more affected than male. By investigating age differences in this area, high heavy metal concentrations in male's hair and urine existed in age of 18-40 and ≥ 66, respectively. However, females did not present homogeneous age distribution. Hair and urine showed a different distribution of heavy metals in different age and gender. In some cases, significant correlation was found between heavy metals in hair and urine (P > 0.05 and P > 0.01) in mining area. The estimated average daily intake of heavy metals in vegetables showed a great contribution compared to the soil and water. Non-carcinogenic and carcinogenic risk values of total pathways in mining and smelting areas were higher than 1 and exceeded the acceptable levels. Thus, the obtained data might be useful for further studies. They can serve as a basis of comparison and assessing the effect of simultaneous exposure from heavy metals in mining and smelting areas, and potential health risks from exposure to heavy metals in vegetables need more consideration.

A population assessment of mercury exposure from two cities of Pakistan with respect to freshwater and marine fish consumption.

In this study, we aimed to estimate the level of mercury (Hg) in scalp hair samples of human subjects and its association with consumption of sea- and freshwater fish species. The scalp hairs were collected from both genders (male and female) aged between 15 and 50 years (n = 200), living in coastal areas of Karachi, who mostly consumed sea fish species, referred to as exposed subjects. For comparison purposes, scalp hair samples of both genders (n = 160) were collected from the inhabitants of Karachi and Hyderabad cities who consumed freshwater fish species termed as referent subjects. The frequently consumed fresh and marine fish species were also collected. The level of Hg was determined in fish and scalp hair samples by cold vapor atomic absorption spectrometry, prior to ultrasonic-assisted acid digestion in a mixture of nitric acid and hydrogen peroxide. The validity of methodology was checked by certified reference material (CRM) BCR 397 (human hair) and DORM-2. The concentrations of Hg in sea- and freshwater fish were found in the range of 1.47-2.09 and 0.402-0.676 µg/g, respectively. The exposed subjects had significantly elevated levels of Hg in scalp hair samples (1.8-4.3 µg/g) as compared to referent subjects (0.87-1.95 µg/g) (p < 0.001). A significant positive correlation was obtained between the concentration of Hg in hair and age of study population. Exposed and referent female subjects had higher levels of Hg in scalp hair than that in males of both study groups (p = 0.02-0.031).

Assessment of environmental and occupational exposure to heavy metals in Taranto and other provinces of Southern Italy by means of scalp hair analysis.

The monitoring of heavy metals in industrialized areas to study their association with different occupational and environmental factors is carried out in different ways. In this study, scalp hair analysis was used for the assessment of exposure to these metals in the industrial city of Taranto, characterized by a severe environmental pollution. The highest median values were observed for aluminum, barium, cadmium, lead, mercury, and uranium. Moreover, in the industrial area of Taranto, high levels of barium, cadmium, lead, mercury, nickel, and silver were observed in comparison with other Apulia areas. The risk odds ratios (ORs) for observing values above the 50th percentile were elevated for mercury and fish consumption, uranium and milk consumption, lead and female sex, and aluminum and mineral water consumption. No significant increased risk was observed for occupational activities. In a dendrogram of a cluster analysis, three clusters were observed for the different areas of Taranto (Borgo, San Vito, and Statte). A scree plot and score variables plot underline the presence of two principal components: the first regarding antimony, lead, tin, aluminum and silver; the second regarding mercury and uranium. The observed clusters (Borgo, San Vito, and Statte) showed that lead, antimony, tin, aluminum, and silver were the main component. The highest values above the 50th percentile of these minerals, especially lead, were observed in the Borgo area. The observed metal concentration in the Borgo area is compatible with the presence in Taranto of a military dockyard and a reported increase of lung cancer risk among residents of that area.

Association of protein intakes and variation of diet-scalp hair nitrogen isotopic discrimination factor in Papua New Guinea highlanders.

OBJECTIVES: We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ(15) NHair-Diet : δ(15) NHair - δ(15) NDiet ) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ(15) N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ(15) N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ(15) N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants. MATERIALS AND METHODS: These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ(15) N was estimated by comparing hair δ(15) N values to mean dietary δ(15) N values calculated from the recorded intake of each food item and their δ(15) N values. RESULTS: The results showed that: i) there was a significant difference in Δ(15) N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2-7.3‰ for all participants); and ii) estimated Δ(15) N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9-7.6%). DISCUSSION: We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ(15) N values of the participants.

Occupational and environmental lead exposure to adolescent workers in battery recycling workshops.

Lead (Pb), as other environmental neurotoxicant substances, has the capability to interfere with many biochemical events present in cells throughout the body. In the present study, the environmental and occupational exposure to Pb has been assessed by analyzing the scalp hair samples of male adolescents aged 12-15 years, who have worked for the last 12-36 months in Pb battery recycling workshops (BRWs). For comparative purposes, gender and age-matched subjects living in the vicinity of recycling workshops as well as in areas without industrial activity were used as controls. The scalp hair samples were oxidized by acid in a microwave oven prior to determination of Pb by electrothermal atomic absorption spectrometry. The results indicated that both workers and nonworking exposed subjects had higher levels of Pb than nonexposed controls. The contents of Pb in scalp hair of adolescent workers in the present study were compared with those reported in other studies.

Children with asthma have significantly lower long-term cortisol levels in their scalp hair than healthy children.

AIM: Noninvasive measurement of long-term cortisol levels is a useful way of evaluating the effect of chronic disease on the hypothalamic-pituitary-adrenal axis in children. The aim of this pilot study was to compare hair cortisol levels in children using inhaled corticosteroids for asthma and healthy children and to determine the association with short-term salivary cortisol levels. METHODS: Cortisol levels were measured in the scalp hair and saliva of prepubertal children with asthma (n = 10) and without asthma (n = 10). Asthma control was assessed using an asthma questionnaire and pulmonary function tests. RESULTS: The median (95% CI) cortisol level in the scalp hair of the children with asthma (2.0 pg/mg; 1.4-4.1) was significantly lower than the healthy children (4.3 pg/mg; 1.8-5.9). Morning salivary cortisol levels were significantly lower for the children with asthma (5.9 nmol/L; 3.2-11.1) than the healthy children (9.0 nmol/L; 4.4-31.6). There was no significant association between cortisol levels in hair and saliva. CONCLUSION: Long-term cortisol levels were significantly lower in children with asthma than healthy children. Measuring long-term cortisol levels in scalp hair is an attractive, noninvasive tool that can evaluate the effect of asthma and its treatment on the hypothalamic-pituitary-adrenal axis.

Risk assessment of arsenic and other metals via atmospheric particles, and effects of atmospheric exposure and other demographic factors on their accumulations in human scalp hair in urban area of Guangzhou, China.

Eighty-eight scalp hair samples were collected from Guangzhou (GZ) urban population (15-65 years) to investigate the accumulation of As and other metals (Cr, Mn, Ni, Cu, Zn, Cd, Sn, Sb, Hg and Pb). Demographic information, including body weight, height, age, gender, habits of smoking and drinking, types of drinking water, duration of stay in GZ, days of stay in GZ per year (days/year), and hours spent in indoor environment per day (h/day), were also recorded during hair sampling to refine the uncertainty of risk assessment derived from exposures to elements via dust and airborne particles. No significant non-carcinogenic risk was found. However, the cancer risks of Cr and As for both ingestion and inhalation exceeded the most tolerable regulated level (1.0×10(-6)). The environmental exposures to urban dust and airborne particles were observed significantly correlated to accumulations of Cd (R=0.306, p=0.005) and Ni (R=0.333, p=0.002) in scalp hair. Furthermore, the hair burden of elements was also significantly (p<0.05) dependent on gender (Mn, Ni, Zn, As, Sn and Hg), age (Cr, As, Cd and Hg), duration of stay in GZ (Hg) as well as nutritional and physical status, reflected by BMI and BSA (Cr, Ni, Cd, Sb and Hg). Nutritional and physical status was observed as the exclusive important factor influencing As speciation in human scalp hair. However, habits of smoking and alcohol drinking as well as types of drinking water were not identified as the significant influencing factors on any element (p>0.05).

Recent Progress in Hair Science and Trichology.

Hair is important to our appearance as well as to protect our heads. Human hair mainly consists of proteins (80-85%), melanin pigments (0-5%), water (10-13%), and lipids (1-6%). The physicochemical properties of hair have been studied for over 100 years. However, they are not yet thoroughly understood. In this review, recent progress and the latest findings are summarized from the following three perspectives: structural characteristics, delivery and distribution of active ingredients, and hair as a template. The structural characteristics of hair have been mainly investigated by microscopic and/or spectroscopic techniques such as atomic force microscopy integrated with infrared spectroscopy (AFM-IR) and rheological measurements. The distribution of active ingredients has been generally evaluated through techniques such as nanoscale secondary ion mass spectrometry (NanoSIMS). And finally, attempts to explore the potential of hair to be used as a substrate for flexible device fabrication will be introduced.