Stem cells are capable of self-renewal and differentiation into various specialized cells, making them a potential therapeutic option in regenerative medicine. This study establishes a comprehensive methodology for isolating, culturing, and characterizing rat hair follicle stem cells. Hair follicles were harvested from Sprague–Dawley rats and subjected to two different isolation techniques. Immunohistochemical analysis and real-time PCR confirm the expression of specific surface markers and genes, validating the cells' identity. Growth kinetics, colony formation units (CFU) and tri-differentiation capacity were also assessed. Additionally, the cells secretome was furthermore analyzed regarding its content in biofactors with wound healing properties. These findings highlight the potential of these cells as a valuable cell source for skin regeneration applications. They contribute to advancing our understanding of stem cell applications in regenerative medicine and hold promise for therapeutic interventions in various clinical contexts, aligning with broader research on the diverse capabilities of hair follicle stem cells.

Androgenetic alopecia is a genetic disorder caused by an excessive response to androgens. This alopecia is the most common cause of progressive hair loss in men and causes low self-esteem in patients. In this study we used various methods, including quantitative PCR, flow cytometry, ELISA, and immunocytochemistry, to evaluate the biological effects of germinated hemp seeds extract and exosomes derived from calli of germinated hemp seeds. This research reveals pre-ventive functions of two biomaterials (GE2000: 2000 ug/mL germinated hemp seeds extract; E40: 40 ng/mL exosomes derived from calli of germinated hemp seeds) for androgenetic alopecia through three biochemical categories: genetic modulation in hair follicle dermal papilla stem cells (HFDPSCs), cellular differentiation, and modulation of immune systems. Despite exposure to dihydrotestosterone (DT), two materials upregulated alopecia preventing genes including Wnt, β-catenin, and TCF in HFDPSCs. Conversely, alopecia activating genes (STAT1, 5α-reductase type 1, and IL-15R) were suppressed. Moreover, two materials suppressed alopecia genes (NKG2DL, IL2-Rβ, JAK1, and STAT1) in CD8+ T cells. Notably, E40 was effected more in-tensely in these biochemical categories than those of GE2000. Consequently, E40 and GE2000 ef-fectively prevented DT stress. Additionally, two materials activated mechanisms for hair for-mation through the biological activities of three categories.

The enormous diversity of hair fibers found in human population is striking, while the basic structure of human fibers is often the same! But why do some fibers curl? Curling is related to the machinery and processes that produce different keratin filament orientation in relation to the axis of hair growth, influenced by developmental and molecular control. It is established that a curly hair shaft is produced by a curved hair follicle that have an angulated dermal implantation, with a bulb bent in the shape of golf club, while the outer root sheath is dissymmetrical; have an outer side that is convex bulging and thin and a concave side in which the cells express alpha-smooth muscle protein reflecting internal mechanical force. Yet, the exact cause of hair curling is not known. All the previous studies were short of impacting curly hair treatment. My hypothesis is that the curling mechanical force is generated by a hypersensitive contracted Arrector Pili muscle (APM) of the hair follicle. In curly hair, each APM fiber is shortened; pulling its attachment spot upward towards the epidermis and obliquely or laterally; curling the outer root sheath to produce the curved follicle described above. This contraction has the influence at a time when the young hair root is being formed and keratin microfibrils are being oriented and packed. APM is a multi-unit muscle wherein each fiber contracts independently to create the enormous diversity of curly hair types. APM contraction can be modulated by oral administration of selective smooth muscle relaxing treatment that relax the curved follicle from within. Further studies are needed to confirm the role of APM in shaping curly hair follicle including AI studies, i.e., computer-aided target identification to demonstrate APM active site that can interact with herbal small molecules.

Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold certain promise for regenerative medicine. This paper is intended to clarify and facilitate the understanding, development and adoption of regenerative medicine in general and specifically of therapies based on unmodified, autologous adipose-derived regenerative cells (UA-ADRCs). To this end, results of landmark experiments on stem cells and stem cell therapy performed in the labs of the authors are summarized, the most intriguing of which are the following: (i) vascular associated mesenchymal stem cells (MSCs) can be isolated from different organs (adipose tissue, heart, skin, bone marrow and skeletal muscle) and differentiated into ectoderm, mesoderm and endoderm, providing significant support for the hypothesis of the existence of a small, ubiquitously distributed, universal vascular associated stem cell with full pluripotency; (ii) the orientation and differentiation of MSCs are driven by signals of the respective microenvironment; and (iii) these stem cells irrespective of the tissue origin exhibit full pluripotent differentiation potential without any prior genetic modification or the need for culturing. They can be obtained from a small amount of adipose tissue when using the appropriate technology for isolating the cells, and can be harvested from and re-applied to the same patient at the point of care without the need for complicated processing, manipulation, culturing, expensive equipment, or repeat interventions. These findings demonstrate the potential of UA-ADRCs for triggering the development of an entire new generation of medicine for the benefit of patients and of healthcare systems.

In the present study, we aimed to observed hair follicle development and describe Wnt10b/β-catenin signaling pathways related to hair follicle development in different ages of Rex rabbits. Six Rex rabbits (3 male and 3 female) of 15, 30, 60, 90, 120 and 150 days of age were selected and skin samples were collected for hair follicle development and Wnt/β-catenin signaling pathway genes expresion detection. The results showed that the the values for body weight, coat length, skin thickness, skin area, and skin weight of Rex rabbits were increased significantly with age (p < 0.05). The total hair follicle density, secondary hair follicle density and the ratio of the secondary hair follicle density to the primary hair follicle density in 120 days of Rex rabbits was higher than that in the other ages (p < 0.05), and the major hair follicles were in the growing period at 15 days and 30 days of age, some of them had already entered the degeneration period at 60 days of age, and most of them entered the degeneration period at 90 days of age, the presence of quiescent hair follicles and the enlargement of primary hair follicles were also observed. At 120 and 150 days of age, the back hair follicles entered the growing period, and the secondary hair follicles had obvious differentiation. Furthermore, the expression of the Wnt10b, CTNNB1, adenomatosis polyposis protein (APC), Disheveled 2 (DVL2), glycogen synthase kinase 3β（GSK-3β）, Lymphoid enhancer-binding factor 1 (LEF1), dickkopf-1 (DKK1) and transforming growth factor beta 1 (TGFβ-1) genes in the skin tissue of Rex rabbits at different age was significantly differences (p < 0.05), and the expression of the Wnt10b, CTNNB1, DVL2, GSK-3β, and TGFβ-1 genes at 90 days was higher than that in the other days, the expression of the LEF1 and DKK1 genes at 60 days was higher than that in the other days. As western blotting indicated, the β-catenin protein phosphorylation (P-CTNNB1) levels in the skin tissue of Rex rabbits shows the trend of first increasing, then decreasing and then increasing, 60 days, 120 days and 150 days significantly higher than 15 days, 30 days or 90 days (p < 0.05). With the increasing of ages, the GSK-3β protein phosphorylation (P-GSK-3β) levels in the skin tissue of Rex rabbits were increasing, and maximum at 120 days of age (p < 0.05). These results show that ages could influence on the fur quality and hair follicle traits of Rex rabbits, and Wnt10b/β-catenin signaling pathways is involved in the biological process of periodic hair follicle development in Rex rabbits. Considering the rule of fur growth, the slaughter age of Rex rabbits should not be earlier than 120 days.

Most hair relaxers or straighteners used for Afro-textured hair have a pH above 11. This pH, according to international occupational health and safety guidelines, is corrosive to the skin. Further, relaxers are associated with a 3-6 times increased risk of alopecia. The skin also gets into contact with these hair straightening products during application resulting in skin irritation. Using animals as test subjects to determine these products' potential risk and safety margin is standard practice; however, with the European Union (EU) ban on animal testing, the testing method needs to be replaced by newer in vitro laboratory technologies. This study used previously and newly established in vitro cell-based technologies and human-skin derived cells as laboratory models to evaluate relaxer-induced cytotoxicity. These technologies include endpoint (MTT, CCK-8 and flow cytometry) and real-time assays (real-time cell analysis (RTCA) and extracellular flux analysis). Cellular toxicity was evident following treatment of keratinocytes and fibroblasts with acceptable concentrations of thioglycolic acid (TGA, HSCH2COOH), ammonium bisulphite (NH4HSO3), lithium hydroxide (LiOH) and sodium hydroxide (NaOH) based relaxers. Real-time assays showed significant reductions (P<0.001) in cell index and ATP production following treatment of keratinocytes with as little as one-tenth of the acceptable concentrations. Increased apoptosis (47.9%, 58.0%, 76.7% and 80.3%) also occurred in cells after treatment with TGA, NH4HSO3, NaOH and LiOH, respectively. In conclusion, this study demonstrated that using skin cells in conjunction with advanced cell-based technologies could serve as alternatives to laboratory animals for accessing the toxicity margin of hair relaxers, straighteners and other cosmetics.

The objective of this study was to investigate the effects of body weight gain during the cashmere non-growing period on cashmere production performance and secondary hair follicle activity, to provide a theoretical basis for appropriate supplementary feeding of cashmere goats. Fifty Inner Mongolian cashmere goats aged 2-4 years old were randomly selected and weighed in May and September 2019, respectively. Based on body weight gain between the two weights, the experi-mental ewe goats were divided into two groups: 0-5.0 kg group (n = 30) and 5.0-10.0 kg group (n = 20). Skin samples and cashmere samples were collected. Results of Pearson correlation analysis showed that body weight gain during the cashmere non-growing period had a moderate and strong positive correlation with cashmere yield (P = 0.021) and cashmere staple length (P = 0.002) respectively, but did not correlate with cashmere diameter (P = 0.254). Compared with cashmere goats with a body weight gain of 0-5.0 kg, cashmere goats with a body weight gain of 5.0-10.0 kg had a 17.10% increment in cashmere yield (P = 0.037), 8.09% increase in cashmere staple length (P=0.045) and had no significant difference in cashmere diameter (P = 0.324). Results of Pearson correlation analysis showed that there was a strong positive correlation between body weight gain and the population of active secondary hair follicles in the skin of cashmere goats (P < 0.01). Compared with cashmere goats with a body weight gain of 0-5.0 kg, cashmere goats with a body weight gain of 5.0-10.0 kg had an increase in the population of active secondary hair follicles (P < 0.05). In conclusion, the body weight gain during the cashmere non-growing period had a sig-nificant effect on secondary hair follicle activity and cashmere production performance in cash-mere goats. Since body weight gain reflects nutritional level to a certain extent, this study suggests that nutritional manipulations such as supplementary feeding during cashmere non-growing periods can increase cashmere production performance. However, specific nutritional manipula-tions during the cashmere non-growing period need further research to increase cashmere pro-duction performance.

Purpose: The aim of this research was to prepare adhesive nanoparticles for the topical application of Minoxidil (MXD). Methods: Thiolated β-CDs were prepared via conjugation of cysteamine with oxidized CDs. MXD was encapsulated within thiolated and unmodified β-CDs. Nanoparticles (Thio-NP and blank NP) were prepared by ionic gelation of CDs with chitosan. Particle size and zeta potential were measured. FTIR analyses were performed for characterization of inclusion complex. Drug dissolution studies were carried out. An in vitro adhesion study over human hair was performed. An in vivo skin irritation study was performed. Ex vivo drug uptake was evaluated by using a Franz diffusion cell. Results: Thiolated β-CDs presented 1804.68 ± 25 μmol/g thiol groups and 902.34 ± 25 μmol/g disulfide bonds. Nanoparticles displayed particle sizes within a range of 231 nm to 319 nm. The zeta potential was in the range of ̶ 8.1 to + 12.0. FTIR analyses confirmed no interaction between the excipients and drug. Delayed drug release was observed from Thio-NP. Thio-NP retained over hair surfaces for a significantly longer time. Similarly, drug retention was significantly improved. Thio-NP displayed no irritation over rabbit skin. Conclusion: Owing to the above results, nanoparticles developed with MXD-loaded thiolated β-CDs might be a potential drug delivery system for topical scalp diseases.

Acute chemical ablation of lateral line hair cells is an important tool to understand lateral line-mediated behaviors in free-swimming fish larvae and adults. However, lateral line-mediated behaviors have not been described in fish larvae prior to swim bladder inflation, possibly because single doses of ototoxin do not effectively silence lateral line function at early developmental stages. To determine if ototoxins can effectively silence the lateral line during early development, we repeatedly expose zebrafish larvae to the ototoxin neomycin during a 36-hour period from 3-4 days post-fertilization (dpf). We use simultaneous transgenic and vital dye labeling of hair cells to compare 6- hour and 12-hour repeated treatment timelines and neomycin concentrations between 0–400 µM in terms of larval survival, hair cell death, regeneration, and functional recovery. Following exposure to neomycin, we find that the emergence of newly functional hair cells outpaces cellular regeneration, likely due to the maturation of ototoxin-resistant hair cells that survive treatment. Furthermore, hair cells of 4 dpf larvae exhibit faster recovery compared to 3 dpf larvae. Our data suggest that the rapid functional maturation of ototoxin-resistant hair cells limits the effectiveness of chemical-based methods to disrupt lateral line function. Furthermore, we show that repeated neomycin treatments can continually ablate lateral line hair cells between 3–4 dpf in larval zebrafish.

The quest for youthful, healthy skin and full, vibrant hair has long been a driving force in the dermocosmetics field. However, traditional approaches often struggle to address the underlying causes of aging, damage, and hair loss. Regenerative cosmetics, powered by skin tissue engineering, offer a transformative alternative. This review explores the emerging field of using engineered skin tissues for cosmetic purposes, focusing specifically on their potential for anti-aging, repair, and hair restoration applications. We discuss how these technologies aim to rejuvenate aging skin by promoting collagen production, reducing wrinkles, and improving overall skin function. Additionally, the use of engineered skin for wound healing and scar reduction is examined, highlighting their potential to improve the appearance and functionality of damaged skin. Finally, we advance the exciting prospects of utilizing skin tissue engineering techniques to regenerate hair follicles, potentially offering solutions for hair loss and promoting denser hair growth.

Human hair is characterized by significant diversity, which is dictated by the individual genetic makeup. It is estimated that up to 70% of the world’s population has textured hair, with a signif-icant proportion also living in areas with high exposure to ultraviolet radiation (UVR). This highlights the unique requirements for textured hair care products that can protect hair shafts from the harmful effects of the environment whilst enhancing the natural features of the fibre. In this study, we investigated the UV-protective effects of hair conditioner formulated from active ingredients, mangiferin, ferulic acid and naringin. The analysis of UV-irradiated straight and textured hair was performed by measurements of hair thickness and darkness, the uptake of the fluorescent dye, spectral absorbance of keratin extracts, ATR-FTIR and SEM. We found that tex-tured hair was more sensitive to UVR-induced changes than straight hair, with the primary mo-lecular targets represented by chemical groups in keratins. Pre-treatment of the hair with condi-tioner had protective effects against structural damage and oxidative stress caused by UVR. These data indicate the importance of the personalized approach to hair research and the formu-lation of hair care products tailored to the individual demands of textured hair types.

Hair cosmetics are in fashion. Numerous products are commonly used in combination. Frequent allergens are present in hair cosmetics, which, added to almost daily use, increase the risk of sensitization. Familiarity with the clinical distribution of the eczematous rash is necessary to seriously consider patch testing. There are haptens on the market, although not all of them. It is necessary to know how to patch your own products. When avoidance of the allergen cannot be possible, new treatments are being evaluated to combat allergic contact dermatitis, mainly of the occupational type. In this manuscript, a complete and practical review of the main allergens and contact sources of hair cosmetic origin has been carried out.

Epoxy matrix composites reinforced with high-performance fibers such as carbon, Kevlar, and glass, exhibit excellent specific stiffness and strength in many mechanical applications. However, these composites are disappointingly non-recyclable and are usually disposed of in landfill sites, with no realistic prospect for biodegradation in reasonable time. In contrast, moldable composites with carbonized elastomeric matrices developed in the last decades possess attractive mechanical properties in final net-shape products and can also be incinerated or recycled. Many carbon and inorganic fillers have recently been evaluated to adjust the properties of carbonized elastomeric composites. Renewable organic fillers such as human or animal hair offer an attractive fibrous material with substantial potential for reinforcing composites with elastomeric matrices. Samples of unidirectional fiber composites (with hair volume fraction up to 7 %) and quasi-isotropic short fiber composites (with hair volume fraction up to 20 %) of human hair-reinforced nitrile butadiene rubbers (HH-NBR) were produced in the peroxide-cured and carbonized states. The samples were characterized using SEM, Raman spectroscopy and photoacoustic microscopy. Mechanical tests were performed in tension using a miniature universal testing machine. The expected effect of fiber reinforcement on the overall mechanical performance has been demonstrated for both cured and carbonized composites. Considerable enhancement of the elastic modulus (up to 10 times), ultimate tensile strength (up to 3 times) and damage tolerance was achieved. The evidence of satisfactory interfacial bonding between hair and rubber was confirmed by SEM imaging of fracture surfaces. The suitability of photoacoustic microscopy was assessed for 3D reconstruction of the fiber sub-system spatial distribution and non-destructive testing.

Accurately diagnosing specific variants of alopecia remains challenging for pathologists, potentially delaying appropriate therapeutic decisions by dermatologists. Issues such as limited knowledge on optimal biopsy types and processing methods add complexity. Understanding the normal histology of hair follicles and their changes throughout the follicular cycle further complicates microscopic evaluation. This paper aims to summarize these characteristics and highlight essential diagnostic clues for pathologists to confidently suggest a diagnosis, therefore playing a key role in alopecia diagnosis. Ongoing education, collaboration with dermatologists, and staying updated on advancements is crucial for accurate diagnosis and effective management of different types of alopecia.

The human scalp is a common site of skin cancer in humans, with non-melanoma skin cancer being exceedingly common. In this review, two dermatologists with extensive experience in cutaneous oncology will discuss unique features of the epidemiology of cancer of the scalp. Clinical observations on these common skin cancers lead to insight into the pathogenesis and potential prevention and treatment of cutaneous scalp neoplasia. Our hypothesis is that the presence of hair protects against the development of skin cancer, but not by serving as a physical shield, but rather by providing a continuous IL-17 biased immunosurveillance. Loss of hair allow release from immunosurveillance, resulting in expansion of neoplastic cells towards skin cancer. Both hair follicles and metabolic changes in stroma allow permissiveness for tumor promotion.

Normally, people lose between 50 and 100 hairs a day and generate new ones from the stem cells of hair follicles, but in people suffering from baldness, the condition called alopecia or androgenetic alopecia, the stem cells remain inactive and are unable to regenerate new hair. The stages of hair growth have been studied to better understand how hair grows and what might be done to prevent or treat premature hair loss. Anagen is referred to as the active phase of hair growth in which the hair shaft is produced by the hair follicle, whereas during catagen and telogen phases the lower part of hair follicle regresses until its growth stops. Although 9% of hair follicles remain in telogen at any one time, a variety of factors including growth factors and cytokines promote the transition from telogen to anagen and the subsequent stimulation of hair growth. In this work, we discuss a new possible treatment, AMPLEX PLUS that could help significantly slow hair loss and encourage new hair growth.

Androgenetic alopecia, the most common cause of hair loss affecting both men and women, is typically treated using pharmaceutical options such as minoxidil and finasteride. While these medications work for many individuals, they are not suitable options for all. To date, the only non-pharmaceutical option that the United States Food and Drug Administration has cleared as a treatment for androgenetic alopecia is low-level laser therapy (LLLT). Various clinical trials utilizing LLLT devices of various types are available. However, a myriad of other physical treatments for this form of hair loss are reported in the literature. This review evaluated the effectiveness of microneedling, pulsed-electromagnetic field (PEMF) therapy, low-level laser therapy (LLLT), fractional laser therapy, and non-ablative laser therapy for the treatment of androgenetic alopecia (AGA). It also explores the potential of multimodal treatments combining these physical therapies. LLLT has the majority of evidence in the literature as a physical therapy for androgenetic alopecia. However, other physical treatments, such as non-ablative laser treatments, and multimodal approaches, such as PEMF-LLLT, seem to have the potential to be equally or more promising and merit further exploration.

Background: Hyaluronic acid (HA) is well known in the cosmetic industry for its hydrating properties linked to its interaction with keratin in the stratum corneum. Hair is also mainly composed of keratin, but no evidence of penetration and interaction of HA in hair had yet been established. Herein, we examined, with appropriate methods, this penetration and interaction. Methods: Confocal Raman Spectroscopy was used to track HA penetration in hair fibers. Human hair was UV-irradiated, or not, before washing with a number of different shampoo formulations. Low-molecular weight hyaluronic acid, high-molecular weight HA, and an optimized blend of low- and high-molecular weight HA, were used. The benefits of HA for cosmetic application were then evaluated at the ex vivo level. Results: Raman analysis of non-irradiated samples revealed that the HA blend penetrated the hair cortex 5.9 times more than the placebo and with irradiated samples, a 1.8-fold increase in penetration was observed. Whatever the irradiation status, penetration of this optimal HA blend was significantly greater than that of the other two active substances. Compared to the placebo, the HA blend significantly decreased spontaneous frizzing by 11%, repaired the hair by increasing the elastic modulus and the break force, and increased the water content in the hair shafts. Conclusion: Confocal Raman Spectroscopy can be considered as a powerful, non-invasive technique to investigate the penetration of active ingredients into the hair.

Noise induces oxidative stress in the cochlea followed by sensory cell death and hearing loss. The proof of principle that injections of antioxidant vitamins and Mg²⁺ prevent noise-induced hearing loss (NIHL) has been established. However, effectiveness of oral administration remains controversial and otoprotection mechanisms unclear. Using auditory evoked potentials, quantitative PCR and immunocytochemistry, we explored effects of oral administration of vitamins A, C, E and Mg²⁺ (ACEMg) on auditory function and sensory cell survival following NIHL in rats. Oral ACEMg reduced auditory thresholds shifts after NIHL. Improved auditory function correlated with increased survival of sensory outer hair cells. In parallel, oral ACEMg modulated the expression timeline of antioxidant enzymes in the cochlea after NIHL. There was increased expression of Glutathione peroxidase-1 and Catalase at 1 and 10 days, respectively. Also, pro-apoptotic Caspase-3 and Bax levels were diminished in ACEMg-treated rats, at 10 and 30 days, respectively, following noise overstimulation, whereas, at day 10 after noise exposure, the levels of anti-apoptotic Bcl-2, were significantly increased. Therefore, oral ACEMg improves auditory function by limiting sensory hair cell death in the auditory receptor following NIHL. Regulation of the expression of antioxidant enzymes and apoptosis-related proteins in cochlear structures is involved in such otoprotective mechanism.

Acne vulgaris is a chronic skin disease, which occurs due to inflammation of the hair follicles and sebum producing (sebaceous) glands of the skin called pilosebaceous unit and the anaerobic propionic acne bacterium, P.acne. Human sebum is dominantly made up of 57.5% of triglycerides and fatty acids, 26%wax esters, 12% Squalene and 4.5% Cholesterol. The increased level Androgen hormone, sebum lipid composition, P.acne over growth which induces monocytes and pro inflammatory cytokines attracts neutrophils, basophils, and T cells to the pilosebaceous unit and drive epithelial hyper proliferation i.e., Acne vulgaris. The actual biomolecular changes due to acne vulgaris disease are present in the blood, in the sebum, and in the noninvasive sample of human scalp hair follicles. The main objectives of the present study are to analyze human scalp hair follicles samples using FTIR-ATR spectroscopy to compare and discriminate the spectral signatures of acne vulgaris and healthy scalp hair tissue samples through acne biomarkers Protein, Amide I, Amide II and Squalene (LDL), using the method of internal ratio parameters. This work represents a first step in the development of an analytical tool for future drug development.

Background: The presence of fungal species on the surface skin and hair is a known finding in many mammalian species and humans are no exception. Superficial fungal infections are sometimes a chronic and recurring condition that affects approximately 10-20% of the world’s population. However, most species that are isolated from humans tend to occur as co-existing flora. This study was conducted to determine the diversity of fungal species isolated from the hair and nails of workers in the central region of Saudi Arabia where there are not many observational studies on the mycological species. Materials and Methods: Male workers from Riyadh, Saudi Arabia were recruited for this study and samples were obtained from their nails and hair for mycological analysis which was done using Saboraud’s agar and sterile wet soil. Fungal isolates were examined microscopically. Results: Twenty four hair samples yielded a total of 26 species from 19 fungal genera. Chaetomiumglobosum was the most commonly isolated fungal species followed by Emericellanidulans, Cochliobolusneergaardii, and Penicilliumoxalicum. Three fungal species were isolated from nail samples, namely, Alternariaalternata, Aureobasidiumpullulans, and Penicilliumchrysogenum. Most of the isolated fungal species (17 of the 26 or 65.38% of the isolated fungal species) have not been thoroughly characterised nor morphologically classified. Conclusion: This study demonstrates the presence of previously undescribed fungal species that contribute to the normal flora of the skin and its appendages and may have a role in their pathogenies.

In nature and engineering applications, flexible fiber beds covering biological surfaces can play a role in reducing resistance. These fibers deform under the action of fluids, and this deformation affects the fluid flow state, forming a complex fluid-solid interaction phenomenon. To quantitatively analyze such issues, the physical model is simplified to the deformation problem of an soft hair bed caused by Stokes flow, and the deformation problem of a single fiber caused by Stokes flow is further studied. The deformation problem of an elastic single fiber in a channel caused by Stokes flow can be described by a nonlinear integral equation. We have obtained a new series solution, which has been compared with the previous perturbation method to verify the accuracy and effectiveness of the series solution. Meanwhile, we have further provided an extended form of flexible fiber deformation through experimental fitting. This fluid-solid interaction problem involves multiple fields and is very important in many natural and engineering systems. The research in this paper can not only help us better understand complex phenomena in nature but also delve into the interaction mechanism between fluids and solids, providing a theoretical basis for future scientific research and engineering applications.

Human hair is characterised by significant variability, determined by genetic and macromolecular factors. Whilst European hair type has been a focus of extensive research, Afro-textured hair care faces challenges created by insufficient knowledge of its unique properties. Applications of hair care products that are incompatible with Afro-textured hair frequently have detrimental effects on the scalp, including alopecia. This highlights the need for scientific and clinical partnerships to bridge the gap between research and hair care practices and address challenges related to Afro-textured hair. In this review, we performed data mining of the existing literature and in-silico network analysis of the biomarkers relevant to Afro-textured hair. The approaches to hair maintenance are highlighted in the context of hair anatomy and growth cycles, organisation of keratins, surface lipids and chemical bonds. We discuss a range of biomarkers affecting hair fibre's shape and mechanical strength, with the gene interactive network pointing to the hierarchical organisation of important traits, notably hair shaft diameter, keratinisation, hair follicle development and patterning. We propose a better understanding of the genetic traits, molecular structure and biomechanics of Afro-textured hair is required to initiate more effective hair care solutions that would benefit the wider population.

The motor protein Prestin found in the outer hair cells (OHCs) of the inner ear is responsible for producing high sensitivity and sharp frequency selectivity for mammalian hearing. Some studies have suggested that Prestin could serve as a serological biomarker for cochlear damage since OHCs are highly vulnerable to damage from various sources of insults. However, the reported data are inconsistent and lack appropriate negative controls. To investigate this further, we measured Prestin quantities in the bloodstream using ELISA kits from different companies. Wildtype (WT) mice were exposed to different ototoxic treatments, including noise exposure and ototoxic reagents that kill OHCs rapidly. Prestin-knockout (KO) mice were used as a negative control. Our data show that some ELISA kits were not able to detect Prestin specifically. The ELISA kit that could detect Prestin protein from cochlear homogenates failed to detect Prestin in the bloodstream despite significant damage to OHCs in cochleae. Furthermore, the optical densities of samples, which correlate to Prestin quantities, were significantly influenced by hemolysis in the samples. In conclusion, Prestin from OHCs is not a sensitive and reliable serological biomarker for detecting cochlear damage in mice.

Much research has been conducted to determine how hair regeneration is regulated, as this could provide therapeutic, cosmetic, and even psychological interventions for hair loss. The current study focused on the hair growth effect and effective utilization of fatty oil obtained from Bryde's whales through high-throughput DNA microarray approach in conjunction with immunohistochemical observations. The research also examined the mechanisms and factors involved in hair growth. In an experiment using female C57BL/6J mice, the vehicle control group (VC: propylene glycol: ethanol: water), the positive control group (MXD: 3% minoxidil), and the experimental group (WO: 20% Whale Oil) were topically applied to the back of the mouse. The results showed that 3% MXD and 20% WO were more effective than VC in promoting hair growth, especially 20% WO. Furthermore, in hematoxylin and eosin-stained skin tissue, an increase in the number of hair follicles and subcutaneous tissue thickness was observed with 20% WO. Whole-genome transcriptomic analysis also showed that 20% WO may have lower stress- and inflammation-related responses than 3% MXD. Therefore, whale oil can be expected to be used as a safe hair growth agent.

Koalas (Phascolarctos cinereus) are one of Australia's most charismatic native small marsupial species. Unfortunately, populations of koalas are rapidly declining throughout Australia and they continue to face increasing pressure from a changing ecosystem. Negative stimulants in the environment can elicit stress responses through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Depending on the duration of the negative stimulant, the stress response can lead to either acute or chronic side effects, and is shown through the activation of the neuroendocrine stress system and the release of glucocorticoids (e.g., cortisol). Wild koalas entering clinical care face novel stressors that can be out of a wildlife carer's control. In this pilot study, we monitored physiological stress in three wild koalas at a wildlife rehabilitation centre in New South Wales, Australia. Acute and chronic stress was indexed non-invasively, with faecal samples taken to evaluate acute stress, and fur samples taken to evaluate chronic stress. Sampling occurred sporadically over four months, from the start of September 2018 to the end of December 2018. Results attempt to understand the stress response of koalas to negative stimulants in the environment by comparing faecal glucocorticoids on days where a known stressor was recorded with days where no known stressor was recorded. Furthermore, variations in faecal and fur glucocorticoids were compared between the three koalas in this study. To our knowledge, this is the first evidence of stress tracking of wild rescued koalas in a sanctuary. We suggest that further monitoring of baseline, acute and chronic stress will be needed to better understand how koalas respond to negative stimulants associated with clinical care.

Anxiety, chronical stress and depression during pregnancy are considered to affect the offspring, presumably through placental dysregulation. We have studied the term placentae of pregnancies clinically monitored with the Beck’s Anxiety Inventory (BAI) and Edinburgh Postnatal Depression Scale (EPDS). A cutoff threshold for BAI/EPDS of 10 classed patients into an Index group (>10, n=23) and a Control group (<10, n=23). Cortisol concentrations in hair (HCC) were periodically monitored throughout pregnancy and delivery. Expression differences of main glucocorticoid pathway genes: i.e. corticotropin-releasing hormone (CRH), 11β-hydroxysteroid dehydrogenase (HSD11B2), glucocorticoid receptor (NR3C1), as well as other key stress biomarkers (Arginine Vasopressin, AVP and O-GlcNAc transferase, OGT) were explored in medial placentae using real-time qPCR and western blotting. Moreover, gene expression changes were considered for their association with HCC, offspring, gender and birthweight. A significant dysregulation of gene expression for CRH, AVP and HSD11B2 genes was seen in the Index group, compared to controls, while OGT and NR3C1 expression remained similar between groups. Placental gene expression of the stress-modulating enzyme 11β-hydroxysteroid dehydrogenase (HSD11B2) was related to both hair cortisol levels (Rho= 0.54; p<0.01) and the sex of the newborn in pregnancies perceived as stressful (Index, p<0.05). Gene expression of CRH correlated with both AVP (Rho= 0.79; p<0.001) and HSD11B2 (Rho= 0.45; p<0.03), and also between AVP with both HSD11B2 (Rho= 0.6; p<0.005) and NR3C1 (Rho= 0.56; p<0.03) in the Control group but not in the Index group; suggesting a possible loss of interaction in the mechanisms of action of these genes under stress circumstances during pregnancy.

The objective of this study was to investigate age-related changes in cashmere production and the population of active secondary hair follicles in cashmere goats across different age groups, as well as to explore the association between secondary hair follicle activity and oxidative stress. A total of 104 adult Inner Mongolian ewe goats, aged between 2 and 7 years old, were randomly selected as experimental subjects. Skin samples were collected in August 2020 and cashmere samples were collected in April 2021. The cashmere fiber yield, staple length, and diameter showed age-related variations in cashmere goats aged 2 to 7 years (P < 0.05). Cashmere production was higher in goats aged 2-4 years compared to those aged 5-7 years (P < 0.05). There were no significant differences in the population of primary and secondary hair follicles among goats aged 2 to 7 years. However, the population of active secondary hair follicles varied significantly with age, with the younger group (aged 2-4 years) having a higher population than those aged 5 – 7 years (P < 0.05). A moderate negative correlation was observed between cashmere fiber diameter and the population of active secondary hair follicles (P < 0.05). Age-related variations in skin antioxidant capacity and oxidative damage were observed among cashmere goats aged 2 to 7 years old (P < 0.05). Goats aged 2 to 4 years exhibited higher antioxidant capacity and lower oxidative damage (P < 0.05). Interestingly, the skin antioxidant capacity and oxidative damage exhibited significant positive and negative correlations, respectively, with the population of active secondary hair follicles (P < 0.05). This study presents a novel approach to enhance the activity of secondary hair follicles and improve cashmere production performance through the regulation of oxidative stress.

The Korean water deer (WD), the dominant wildlife species in South Korea, is classified as vul-nerable on the IUCN Red List. Beside their several unique characteristics, they have a lower in-cidence of tick bites compared to other Cervidae species, particularly roe deer (RD). In natural environments, ticks exhibit questing behavior by waiting on grasses to climb onto host's hair coat. They use sensory organs to detect signals such as body temperature and chemicals from the host's skin, then move to preferred feeding location. Therefore, we conducted a comparative analysis of the skin tissue and hair features of both species to compare the factors leading to lower incidence of tick bites in WD. Notably, WD had significantly larger blood vessels, sebaceous glands, and sweat glands which maintain the barrier functions of the skin (p≤0.004), irregular scale surfaces in hair cuticles, and stiff and 2.83-times thicker primary hair diameter (p<0.001). Each parameters made the ticks difficult to move onto the epidermis of WD. To our knowledge, this is the first report which is focused on the comparative analysis for skin and hair feature in WD and RD. We suggest that these differences may attribute to evade tick bites in WD.

A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Background: Place the question addressed in a broad context and highlight the purpose of the study; (2) Methods: briefly describe the main methods or treatments applied; (3) Results: summarize the article's main findings; (4) Conclusions: indicate the main conclusions or interpretations. The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions.

Background: Drug incorporated in hair are exposed to the environment and to cosmetic and chemical treatments, with possible decrease of their content. Knowledge concerning the effect of sun light on drug content in hair can be helpful to the forensic toxicologist, in particular when investigating on drug concentrations above or below pre-determined cut-offs. Materials and Methods: Twenty authentic positive hair samples were selected that had previously tested positive for amphetamines and/or ketamine. Washed hairs were divided into two identical strands: the former was exposed at 765 W/m² (310–800 nm spectrum of irradiance) for 48 hours in a solar simulator, the latter was kept in the dark. Hair samples were extracted and analyzed by LC-HRMS detection. The percent photodegradation was calculated for each analyte (amphetamine, methamphetamine, methylendioxyamphetamine methylendioxymethamphetamine, ketamine, norketamine). In parallel, photodegradation processes of standard molecules dissolved in aqueous and organic solutions were studied. Results: In 20 hair samples positive for the targeted analytes, exposure to artificial sun light induced an appreciable decrease of drug concentrations. The concentration ranges in the non-irradiated hair samples were 0.01–24 ng/mg; 65% of samples exhibited a decrease in post-irradiation samples, with reduction from 3% to 100%. When more drugs were present in the same hair sample (e.g, MDMA and ketamine) the degradation yields were compound dependent. A degradation product induced by irradiation of ketamine in aqueous and methanol solutions was identified; it was also found to be present in a true positive hair sample after irradiation. Conclusions: Ketamine, amphetamines and their metabolites incorporated in hair of drug users undergo degradation when irradiated by artificial sunlight. Only for ketamine a photoproduct was identified in irradiated standard solutions and in true positive irradiated hair. When decisional cut-offs are applied to hair analysis, photodegradation must be taken into account since sunlight may produce false negative results. Moreover, new markers could be investigated as evidence of illicit drug use.

Background: We prepared reference materials of fentanyl and amphetamines in hair, and established methods for the certification of reference materials of fentanyl and amphetamines in hair samples. Methods: Hair samples containing 15 drugs were prepared by immersion method (water-dimethylsulfoxide). On the basis of single-factor experiment, Box-Behnken design-response surface was used to optimize the pre-treatment conditions of samples. In MRM/SIM mode, 15 drugs were quantitatively analyzed by LC-MS/MS and GC-MS/MS methods. Results: The contents of 15 drugs in the mixed hair samples were: 1.050 ng mg-1~7.771 ng mg-1, RSDs&lt;7%(n=11). The results showed that the two analytical methods developed were highly sensitive (LODs as low as 0.05 pg mg-1), reproducible (intra-day and inter-day precision RSDs were&lt;10%) and accurate. F-test was performed on the prepared hair samples and the results showed that the homogeneity of the prepared hair samples was good. Conclusions: The established methods were used for the detection of fentanyl and amphetamine drugs in human hair, with high sensitivity, accuracy and specificity. It can be used as a certified method for the development of fentanyl and amphetamine matrix certified reference materials. The developed hair reference materials are expected to be applied in forensic drug abuse detection and laboratory quality control.

A correlation of basic science and clinical symptoms in the human to propose a new theory for how the vestibular system works Neil S. Longridge Professor Emeritus, Division of Otolaryngology Department of Surgery, Faculty of Medicine, University of British Columbia Vancouver, BC CANADA *Arthur I. Mallinson, Clinical Associate Professor, Division of Otolaryngology Department of Surgery, Faculty of Medicine, University of British Columbia Vancouver, BC CANADA NS Longridge † *AI Mallinson † These authors contributed equally to this work. ABSTRACT; Bipedalism is unique among mammals. Until modern times, a fall and resulting leg fracture could be fatal. Balance maintenance after a destabilizing event requires instantaneous decision-making. The vestibular system plays an essential role in this process, initiating an emergency response. The afferent otolithic neural response is the first directionally oriented information to reach the cortex, and can then be used to initiate an appropriate protective response. Some vestibular efferent axons feed directly into the type I vestibular hair cells. This allows for rapid vestibular feedback via the striated organelle (STO), which has been largely ignored in most texts. We propose that this structure is essential in emergency fall prevention, and also that the system of sensory detection and resultant motor response works by having efferent movement information transmitted to the maculae simultaneously with the movement commands. This results in the otolithic membrane positioning itself precisely for the planned movement, and any error is due to an unexpected external cause. Error is fed back via the vestibular afferent system. The efferent system through the STO causes macular otolithic membrane movement which occurs simultaneously with the initiating motor command. As a result, no vestibular afferent activity occurs unless an error must be dealt with.

This work compares the multi-element analysis of human hair and nails using inductively coupled plasma mass spectrometry (ICP-MS) with an easy, fast, cheap, non-destructive method using energy dispersive x-ray fluorescence (EDX-RF). The ICP-MS-based method was more sensitive (over 30 elements could be quantified) and costly (requiring more time, sample, and chemicals). The EDX-based method required laboratory and certified reference materials made of hair for instrument calibration. It was less sensitive (16 elements could be quantified: S, Si, Ca, Br, Fe, Cu, Cr, Mg, Si, K, Mn, Ni, Zn, Se, Sr, Pb), but it allowed to replace troublesome grinding with the dissolution of keratin-based material with alkalic agent (tetramethylammonium hydroxide, TMAH) and formation of stable for days pellets. The method is simple, enables automation, and, due to the modification of wells in the autosampler of the EDX system by immersion of home-designed inserts, it requires smaller amounts of biological material and binder (down to 70 mg instead of 500 mg required by commercially available instrument) to perform analysis. It was concluded that the EDX-based method offers complementary selectivity and sensitivity to ICP-MS with the possibility of the reuse of the sample for further analysis.

The epidermis is the outermost layer of skin and provides a protective barrier against environmental insults. It is a rapidly renewing tissue undergoing constant regeneration, maintained by several types of stem cells. Hedgehog (HH) ligands activate one of the fundamental signaling pathways that contribute to epidermal development, homeostasis and repair. The HH pathway interacts with other signal transduction pathways such as those activated by Wnt and bone morphogenetic protein. Furthermore, aberrant activation of HH signaling is associated with various tumors, including basal cell carcinoma. Therefore, an understanding of the regulatory mechanisms of the HH signaling pathway is important to elucidate fundamental mechanisms underlying both organogenesis and carcinogenesis. In this review, we discuss the role of the HH signaling pathway in skin development, homeostasis and basal cell carcinoma formation, providing an update of current knowledge in this field.

This research explores the feasibility of a data-driven optimization algorithm for placing sparse arrays of artificial hair-cell airflow velocity sensors to enable agile and robust flight-by-feel control of unmanned aircraft. The Sparse Sensor Placement Optimization for Prediction (SSPOP) algorithm exploits the information-rich features of large flow datasets to find a near-optimal set of locations for flow sensors on a wing. The flow information from these sensors can be used to predict flight state parameters such as the angle of attack, mimicking the fly-by-feel control systems observed in nature. We evaluate the effectiveness of this approach for a blunt-edged 45∘ swept delta wing. Exploiting the information in the complex airflow patterns over this wing, the SSPOP algorithm selects a sensor location design point (DP) which reliably ranks within the top 1% of all possible DPs by root mean square error in angle of attack prediction. This performance was consistent across models of various artificial hair lengths, and one model with variable hair lengths. This bioinspired dimension-reducing method for sensor placement optimization exhibits reliability and flexibility benefits when compared with a conventional greedy search algorithm and gradient-based optimization using auto-differentiation. The successful application of SSPOP in complex 3D flows paves the way for experimental evaluation of data-driven sparse sensor placement optimization for artificial hair-cell airflow sensors and is a major step toward biomimetic flight-by-feel.

Auxin and ethylene pathways cooperatively regulate a variety of developmental processes in plants. Growth responses to ethylene are largely dependent on auxin, the key regulator of plant morphogenesis. Auxin, in turn, is capable of inducing ethylene biosynthesis and signaling making the interaction of these hormones reciprocal. Recent studies discovered a bunch of molecular events underlying auxin-ethylene crosstalk. In this review, we summarize the results of fine-scale and large-scale experiments on interaction of auxin and ethylene pathways in Arabidopsis. We integrate the knowledge on the molecular crosstalk events, their tissue specificity and associated phenotypic responses to decipher the crosstalk mechanisms at a systems level. We also discuss the prospects of applying systems biology approaches to study the mechanisms of crosstalk between plant hormones.

The visual appearance of humans derives significantly from our skin and hair color. While melanin from epidermal melanocytes protects our skin from the damaging effects of ultraviolet radiation, the biological value of pigmentation in the hair follicle, particularly in the scalp, is less clear. In this study, we explore the heterogeneity of pigment cells in the human scalp anagen hair follicle bulb, a site conventionally viewed to be focused solely on pigment production for transfer to the hair shaft. Using c-KIT/CD117 microbeads, we isolated bulbar c-KIT-positive and c-KIT-negative melanocytes. While both subpopulations expressed MITF, only the c-KIT-positive fraction expressed SOX10. We further localized bulbar melanocyte subpopulations (expressing c-KIT, SOX10, MITF, and DCT) that exhibited distinct/variable expression of downstream differentiation-associated melanosome markers (e.g., gp100 and Melan-A). Localization of a second ‘immature’ SOX10 negative melanocyte population, which was c-KIT/MITF double positive, was identified outside of the melanogenic zone in the most peripheral/proximal matrix. These studies describe an approach to purifying human scalp anagen hair bulb melanocytes, allowing us to identify unexpected levels of melanocyte heterogeneity. The function of the more immature melanocytes in this part of the hair follicle remains to be elucidated. Could they be in-transit migratory cells destined to synthesize mela-nin ultimately or could they contribute to the hair follicle in non-melanogenic ways.

Building on the job demands-resources (JD-R) and the allostatic load (AL) models, in this study we investigated the role of smart working (SW) in the longitudinal association between workload/job autonomy (JA) and a possible biomarker of work-related stress (WRS) in the hair, namely the cortisol to dehydroepiandrosterone sulphate (DHEA(S)) ratio, during the COVID-19 pandemic. Overall, 124 workers completed a self-report questionnaire (i.e., psychological data) at Time 1 (T1) and collected a strand of hair (i.e., biological data) three months later (Time 2, T2). Results from moderated multiple regression analysis showed that smart working at T1 was negatively associated with hair cortisol/DHEA(S) ratio at T2. Additionally, the interaction between workload and SW was significant, with workload at T1 being positively associated with hair cortisol/DHEA(S) ratio at T2 among smart workers. Overall, this study indicates that SW can be conceived as a double-edged sword, with both positive and negative consequences on employee well-being. Furthermore, our findings suggest that hair cortisol/DHEA(S) ratio is a promising biomarker of WRS. Practical implications that organizations and practitioners can adopt to promote organizational well-being are discussed.

Black hole collision produce gravitational radiation which is generally thought in a quantum limit to be gravitons. The stretched horizon of a black hole contains quantum information, or a form of quantum hair, which in a coalescence of black holes participates in the generation of gravitons. This may be facilitated with a Bohr-like approach to black hole (BH) quantum physics with quasi-normal mode (QNM) approach to BH quantum mechanics. Quantum gravity and quantum hair on event horizons is excited to higher energy in BH coalescence. The near horizon condition for two BHs right before collision is a deformed AdS spacetime. These excited states of BH quantum hair then relax with the production of gravitons. This is then argued to define RT entropy given by quantum hair on the horizons. These qubits of information from a BH coalescence should then appear in gravitational wave (GW) data. This is a form of the standard AdS/CF T correspondence and the Ryu-Takayanagi (RT) formula [1]. The foundations of physics is proposed to be quantum information and a duality between spacetime observables and quantum fields.

(1) Background: Considering the autoimmune nature with genetic predisposition of alopecia areata, and the immunomodulatory properties of some probiotics, the present study was conducted in patients with alopecia areata. (2) Method: A 24-weeks randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy of an oral probiotic intake in severity of alopecia areata and the effect on skin and gut microbiota. 3) Results: The number of alopecia areata plaques decresed in 56% of patients in the probiotic group vs. 30% in the placebo group. Patients with improvement on the affected skin surface area, showed a results of 45% and 20% in probiotic and placebo groups, respectively. For "activity", "inactivity” and "regrowth", an improvement in 55%, 67% and 55% of patients was respectively observed in the probiotic group, compared to 50%, 40% and 30% in the placebo group. No changes were observed in the gut microbiota during the intervention period. Regarding skin microbiota, changes were detected in the probiotic group, with reductions in characteristic genera during the study. (4) Conclusions: To our knowledge, this is the first clinical trial assessing the efficacy of a probiotic in patients with alopecia areata. This probiotic mixture improves the course and modify the skin microbiota of these patients.

Using the principle of equivalence, it has recently been shown that the electrostatic field lines of a charge, stationary in the gravitational field, bend exactly like the trajectories of photons emitted isotropically from a source at the charge location and that the fraction of electric flux crossing a surface `below' or `above' the charge is exactly similar to the fraction of photon trajectories intersecting these surfaces, with more flux in the downward direction than upward. As one goes much deeper in the gravitational field, all electric field lines increasingly point in the vertically downward direction as is also the case for a stream of photons. Since photon trajectories as well as electric field lines, at any location in the gravitational field, are affected by the local space-time curvature an inference can be drawn that this parallel between the photon trajectories and the electric field lines is a general result. We could then apply these results in the external gravitational field of a black hole, where the trajectories of photons in the gravitational field are already well-known and the behaviour of electric field lines of a stationary charge could be inferred therefrom. Accordingly, we show that the electric field through an external spherical surface surrounding the black hole steadily reduces as the charge location approaches the event horizon (Schwarzschild radius), and like photons from a source inside the Schwarzschild radius cannot escape outside, the electric field lines of a charge within the black hole too remain trapped inside the event horizon. From this one arrives at a conclusion that, contrary to the conventional wisdom, the electric charge contained inside a static black hole cannot be detected or inferred by an external observer. A black hole, said to have no hair with the only external identifying characteristics being mass, electric charge, and angular momentum, is therefore all the more `hairless', as even its charge cannot be ascertained. The derivation of the Reissner-Nordström metric, supposedly describing the gravitational field of a static charged black hole, presumes an external stress-energy tensor of the electrostatic field, as per Gauss law, even for the charges contained within the black hole. However, the absence of electric flux external to a static charged black hole implies that such a charged black hole is not described correctly by the Reissner-Nordström metric and the consequential peculiarities of the space-time geometry, leading in specific cases to the idea of a naked intrinsic singularity and a need for the ``cosmic censorship'' hypothesis, also do not arise here.