Examining visual measures of coat and body condition in wild ring-tailed lemurs at the Bezà Mahafaly Special Reserve, Madagascar

Coat and body mass status provide a potential noninvasive way to assess primate health status as well as the effects of seasonality, resource use and reproductive state. Coat and body condition were scored visually for 36 wild Lemur catta at the Bezà Mahafaly Special Reserve, Madagascar, from July 2012 to March 2013. Coat quality generally increased during the wet season when resource availability increased, in contrast to that observed during the resource-depleted dry season. Alopecia frequency increased from June to December and declined between January and March. Sex differences for coat condition were only observed in January, when males had superior coat scores. Body condition did not vary by month or sex except in February, when males were larger than females. Females that birthed infants were of lower body size than individuals who did not for November and from January to March. Our results indicate visual methods effectively detect variability in coat and body condition related to seasonality and reproductive status. Such methods present a noninvasive means for assessing the impact of seasonal resource availability, stresses of infant care and reproductive state on ring-tailed lemurs, and may be useful for assessing the impacts of these factors on general health status.

The effect of hair density on the coupling between the tactor and the skin of the human head

The purpose of this study was to determine the effect of hair density on vibration detection thresholds associated with the perception of low frequency vibration stimuli applied to the head. A host of tactile sensitivity information exists for other parts of the body, however the same information is lacking for the head. Thirty-three college students, age 18-35, were recruited for the study. A mixed design was used to evaluate the effect of hair density, head location, and frequency on vibration detection thresholds. Results suggest that hair density might slightly impede vibration signals from reaching the scalp and reduce vibration sensitivity, for the least sensitive locations on the head. This research provides design recommendations for head-mounted tactile displays for women and those with hair that can be used to convey directional cues for navigation and as alerts to critical events in the environment.

Carbon (δ13C) and Nitrogen (δ15N) Stable Isotope Signatures in Bat Fur Indicate Swarming Sites Have Catchment Areas for Bats from Different Summering Areas

Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ13C and δ15N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ13C and δ15N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEAc), of bats at swarming sites and much less overlap in SEAc among groups sampled at summering areas. Meaningful inference could not be made on M. septentrionalis because their low variation in SEAc may have been the result of sampling only 3 summering areas. However, for M. lucifugus, swarming sites had larger SEAc than summering areas and predictive discriminant analysis assigned swarming bats to multiple summering areas, supporting the contention that swarming bats are mixed aggregations of bats from several summering areas. Together, these data support the contention that swarming sites have catchment areas for bats from multiple summering areas and it is likely that the catchment areas for swarming sites overlap. These data suggest that δ13C and δ15N profiling of bat fur offer some potential to make inferences about regional migration in bats.

2.5D Cartoon Hair Modeling and Manipulation

This paper addresses a challenging single-view modeling and animation problem with cartoon images. Our goal is to model the hairs in a given cartoon image with consistent layering and occlusion, so that we can produce various visual effects from just a single image. We propose a novel 2.5D modeling approach to deal with this problem. Given an input image, we first segment the hairs of the cartoon character into regions of hair strands. Then, we apply our novel layering metric, which is derived from the Gestalt psychology, to automatically optimize the depth ordering among the hair strands. After that, we employ our hair completion method to fill the occluded part of each hair strand, and create a 2.5D model of the cartoon hair. By using this model, we can produce various visual effects, e.g., we develop a simplified fluid simulation model to produce wind blowing animations with the 2.5D hairs. To further demonstrate the applicability and versatility of our method, we compare our results with real cartoon hair animations, and also apply our model to produce a wide variety of hair manipulation effects, including hair editing and hair braiding.

Normal and aging hair biology and structure 'aging and hair'

Much like an individual's hairstyle, hair fibers along the scalp see a number of changes over the course of one's lifetime. As the decades pass, the shine and volume synonymous with youthful hair may give way to thin, dull, and brittle hair commonly associated with aging. These changes are a result of a compilation of genetic and environmental elements influencing the cells of the hair follicle, specifically the hair follicle stem cells and melanocytes. Telomere shortening, decrease in cell numbers, and particular transcription factors have all been implicated in this process. In turn, these molecular alterations lead to structural modifications of the hair fiber, decrease in melanin production, and lengthening of the telogen phase of the hair cycle. Despite this inevitable progression with aging, there exists an array of treatments such as light therapy, minoxidil, and finasteride which have been designed to mitigate the effects of aging, particularly balding and thinning hair. Although each works through a different mechanism, all aim to maintain or potentially restore the youthful quality of hair.

Bio-inspired flow sensor from printed PEDOT:PSS micro-hairs

This paper reports on the creation of a low-cost, disposable sensor for low flow velocities, constructed from extruded micro-sized 'hair' of conducting polymer PEDOT. These microstructures are inspired by hair strands found in many arthropods and chordates, which play a prime role in sensing air flows. The paper describes the fabrication techniques and the initial prototype testing results toward employing this sensing mechanism in applications requiring sensing of low flow rates such as a flow sensor in neonatal resuscitators. The fabricated 1000 μm long, 6 μm diameter micro-hairs mimic the bending movement of tactile hair strands to sense the velocity of air flow. The prototype sensor developed is a four-level direct digital-output sensor and is capable of detecting flow velocities of up to 0.97 m s(-1).

[Hair and their environment]

Hair is influenced by the effects of the daily environment. Some toxic xenobiotics slow down or block the cell renewal of the hair matrix, thus inhibiting hair growth. The ultraviolet light obviously influences the physical structure and physiology of the hair follicle. Tobacco is similarly responsible for negative influences on the evolution of various alopecias. Several cosmetic procedures for maintaining and making hair more attractive are not always harmless, and they occasionally represent a possible origin for alopecia.

Electroencephalogram measurement from the hairy part of the scalp using polymer-based dry microneedle electrodes

This paper reports a successful electroencephalogram (EEG) measurement from the hairy part of the scalp using a polymer-based dry microneedle electrode. The electrode consists of 25 pillars, each of which has a sharp microneedle on the top. Hairs are collected into the gaps of the pillars and the microneedles can reach the scalp surface. Since the microneedles can penetrate through the stratum corneum, no conductive gel is necessary to acquire high quality EEG. We experimentally investigated the pillar diameters in EEG measurement from the occipital region with hairs. The fabricated electrodes successfully measured EEG without any skin preparation or conductive gel.

Performance assessment of bio-inspired systems: flow sensing MEMS hairs

Despite vigorous growth in biomimetic design, the performance of man-made devices relative to their natural templates is still seldom quantified, a procedure which would however significantly increase the rigour of the biomimetic approach. We applied the ubiquitous engineering concept of a figure of merit (FoM) to MEMS flow sensors inspired by cricket filiform hairs. A well known mechanical model of a hair is refined and tailored to this task. Five criteria of varying importance in the biological and engineering fields are computed: responsivity, power transfer, power efficiency, response time and detection threshold. We selected the metrics response time and detection threshold for building the FoM to capture the performance in a single number. Crickets outperform actual MEMS on all criteria for a large range of flow frequencies. Our approach enables us to propose several improvements for MEMS hair-sensor design.

Microfluidic Isolation of CD34-Positive Skin Cells Enables Regeneration of Hair and Sebaceous Glands In Vivo

Skin stem cells resident in the bulge area of hair follicles and at the basal layer of the epidermis are multipotent and able to self-renew when transplanted into full-thickness defects in nude mice. Based on cell surface markers such as CD34 and the α6-integrin, skin stem cells can be extracted from tissue-derived cell suspensions for engraftment using the gold standard cell separation technique of fluorescence-activated cell sorting (FACS). This paper describes an alternative separation method using microfluidic devices coated with degradable antibody-functionalized hydrogels. The microfluidic method allows direct injection of tissue digestate (no preprocessing tagging of cells is needed), is fast (45 minutes from injected sample to purified cells), and scalable. This method is used in this study to isolate CD34-positive (CD34+) cells from murine skin tissue digestate, and the functional capability of these cells is demonstrated by transplantation into nude mice using protocols developed by other groups for FACS-sorted cells. Specifically, the transplantation of microfluidic isolated CD34+ cells along with dermal and epidermal cells was observed to generate significant levels of hair follicles and sebaceous glands consistent with those observed previously with FACS-sorted cells.

To each its own: Thermoregulatory strategy varies among neonatal polar phocids

Cold environmental conditions and small body size promote heat loss and may create thermoregulatory challenges for marine mammals born in polar regions. However, among polar-born phocid seal species there are variations in physical attributes and environmental conditions at birth, allowing for an interesting contrast in thermoregulatory strategy. We compared thermoregulatory strategies through morphometrics, sculp attributes (conductivity and resistance), nonshivering thermogenesis (NST via uncoupling protein 1; UCP1), and muscle thermogenesis (via enzyme activity) in neonatal harp (Pagophilus groenlandicus), hooded (Cystophora cristata), and Weddell seals (Leptonychotes weddellii). Harp seals are the smallest at birth (9.8±0.7 kg), rely on lanugo (82.49±3.70% of thermal resistance), and are capable of NST through expression of UCP1 in brown adipose tissue (BAT). In contrast, hooded seal neonates (26.8±1.3 kg) have 2.06±0.23 cm of blubber, accounting for 38.19±6.07% of their thermal resistance. They are not capable of NST, as UCP1 is not expressed. The large Weddell seal neonates (31.5±4.9 kg) rely on lanugo (89.85±1.25% of thermal resistance) like harp seals, but no evidence of BAT was found. Muscle enzyme activity was highest in Weddell seal neonates, suggesting that they rely primarily on muscle thermogenesis. Similar total thermal resistance, combined with marked differences in thermogenic capacity of NST and ST among species, strongly supports that thermoregulatory strategy in neonatal phocids is more closely tied to pups' surface area to volume ratio (SA:V) and potential for early water immersion rather than mass and ambient environmental conditions.

Novel active comb-shaped dry electrode for EEG measurement in hairy site

Electroencephalography (EEG) is an important biopotential, and has been widely applied in clinical applications. The conventional EEG electrode with conductive gels is usually used for measuring EEG. However, the use of conductive gel also encounters with the issue of drying and hardening. Recently, many dry EEG electrodes based on different conductive materials and techniques were proposed to solve the previous issue. However, measuring EEG in the hairy site is still a difficult challenge. In this study, a novel active comb-shaped dry electrode was proposed to measure EEG in hairy site. Different form other comb-shaped or spike-shaped dry electrodes, it can provide more excellent performance of avoiding the signal attenuation, phase distortion, and the reduction of common mode rejection ratio. Even under walking motion, it can effectively acquire EEG in hairy site. Finally, the experiments for alpha rhythm and steady-state visually evoked potential were also tested to validate the proposed electrode.

A biomimetic accelerometer inspired by the cricket's clavate hair

Crickets use so-called clavate hairs to sense (gravitational) acceleration to obtain information on their orientation. Inspired by this clavate hair system, a one-axis biomimetic accelerometer has been developed and fabricated using surface micromachining and SU-8 lithography. An analytical model is presented for the design of the accelerometer, and guidelines are derived to reduce responsivity due to flow-induced contributions to the accelerometer's output. Measurements show that this microelectromechanical systems (MEMS) hair-based accelerometer has a resonance frequency of 320 Hz, a detection threshold of 0.10 ms(-2) and a dynamic range of more than 35 dB. The accelerometer exhibits a clear directional response to external accelerations and a low responsivity to airflow. Further, the accelerometer's physical limits with respect to noise levels are addressed and the possibility for short-term adaptation of the sensor to the environment is discussed.

Analysis of the torsional storage modulus of human hair and its relation to hair morphology and cosmetic processing

Through measurements of three different hair samples (virgin and treated) by the torsional pendulum method (22°C, 22% RH) a systematic decrease of the torsional storage modulus G' with increasing fiber diameter, i.e., polar moment of inertia, is observed. G' is therefore not a material constant for hair. This change of G' implies a systematic component of data variance, which significantly contributes to the limitations of the torsional method for cosmetic claim support. Fitting the data on the basis of a core/shell model for cortex and cuticle enables to separate this systematic component of variance and to greatly enhance the discriminative power of the test. The fitting procedure also provides values for the torsional storage moduli of the morphological components, confirming that the cuticle modulus is substantially higher than that of the cortex. The results give consistent insight into the changes imparted to the morphological components by the cosmetic treatments.

Changes in the mechanical parameters of hair in a group of women in reproductive age

OBJECTIVE

Hair quality and scalp characteristics are considered to be a significant marker of health. This marker is reflected in mechanical properties of hair. To investigate these properties, hair samples have been collected among women of different age and then analyzed. The thickness, Young's modulus of elasticity and ultimate strength limit were the main observed parameters.

METHODS

The diameter of each hair has been measured using an optical microscope equipped with a digital camera. The hair was then clipped into the uniaxial tensile testing device. Each sample has been stretched to failure at a speed of 2 mm/min and force vs. elongation was recorded. The mechanical results were converted with respect to the diameter and Stress-Strain curve was obtained for each sample. In addition, all the analyzed samples were divided into two groups in dependence on the age, namely samples from women younger than 35 and over 35 years of age. All the measured parameters were statistically evaluated.

RESULTS

Young's modulus, yield and elongation parameters showed no significant difference among samples. On the other hand there was a significant difference among the samples in ultimate strength values. Findings from group analysis showed that women under 35 years show about 5 times greater variability in hair strength than that of women above that age.

CONCLUSION

The results of our study indicate that hair tendency to grow persists up to 30 years of age, then slowly decreases and then achieves a steady state around 60 years of age.

The biology, structure, and function of eyebrow hair

Eyebrow hair serves many important biologic and aesthetic functions. This article reviews the structure and function of the hair follicle, as well as hair follicle morphogenesis and cycling. Eyebrow hair follicles share the same basic structure as hair follicles elsewhere on the body, but are distinguished by their shorter anagen (growing) phase. Knowledge of the hair follicle structure and cycle is important for understanding the pathophysiology of alopecia, as diseases affecting the stem cell portion of the hair follicle in the bulge region may cause permanent hair loss. Furthermore, therapeutic agents that target distinct phases and hormones involved in the hair cycle may be useful for promoting hair growth.

Theoretical analysis of body hair movement in ELF electric field exposure in different environmental conditions

To elucidate the mechanism of the biological effect of ELF (extremely low frequency, 0-300 Hz) electric field and to settle appropriate safety standards, the body hair movement in AC electric field exposure was analyzed. We derived the equation of motion to describe the body hair movement cause by the electric force, and obtained an analytic solution for AC input. We applied this solution to practical conditions and clarified the body hair movement in AC electric field exposure. Using this solution, we analyzed the body hair movement in different humidity and verified the validity of the analysis in experiments.

[Experimental research of hair follicle reconstruction with the aid of embryonic mice dermal cells]

OBJECTIVE

To investigate the effect of embryonic dermal signal on the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro.

METHODS

Embryonic mice dermal cells of embryonic day 14 were added to a chamber on the back of nude mice with neonatal mice dermal cells which had been amplified in vitro for 3 days and freshly isolated neonatal mice epidermal cells. The hair regeneration was compared between the groups with or without embryonic mice dermal cells. Meanwhile, chambers with following cells respectively were constructed as controls: embryonic mice dermal cells + neonatal mice epidermal cells; freshly isolated neonatal mice dermal cells + neonatal mice epidermal cells; amplified neonatal mice dermal cells only; embryonic mice dermal cells only; freshly isolated neonatal mice dermal cells only; neonatal mice epidermal cells only.

RESULTS

The number of regenerated hairs with the aid of embryonic mice dermal cells (207 +/- 15. 948) was significantly higher than that (67 +/- 8.963) in the group without embryonic mice dermal cells (n = 3, t = 7.653, P = 0.002).

CONCLUSION

Embryonic dermal signal can enhance the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro.

Hair and scalp disorders in ethnic populations

Human hair has been classified into 3 major groups, as determined by ethnic origin. In these populations, significant structural and biochemical variations of the hair follicle and shaft are seen, as well as unique hair grooming practices. These structural variations of the hair are closely linked to the common disorders of the hair and scalp, such as acquired trichorrhexis nodosa, seborrheic dermatitis, traction alopecia, central centrifugal cicatricial alopecia, dissecting cellulitis, frontal fibrosing alopecia, and pseudofolliculitis barbae.

[Coat changes in castrated bitches - a review of the literature]

OBJECT

Literature on veterinary medicine was searched for information on coat changes in castrated bitches. The data obtained was evaluated according to criteria of evidence-based veterinary medicine, to gain an objective basis for the evaluation of this undesired spaying-induced effect.

MATERIAL AND METHODS

The literature search was carried out via the search function of PubMed and of the "Deutsche Nationalbibliothek" (DNB). Furthermore, German journals were surveyed for relevant papers.

RESULTS

A total of 16 publications concerning the subject were found: ten expert opinions, three case series and three cohort studies.

CONCLUSION

Publications on "coat changes in castrated bitches" are rare. The contemporary literature is predominantly comprised of expert opinions and is therefore of little evidentiary value.

CLINICAL RELEVANCE

Because coat changes following spaying in bitches are often described, dog owners should be informed about these possible secondary effects after spaying. Analysis of frequency and promotive factors with high evidentiary value are still lacking. Consequently, it is difficult or impossible to predict the individual risk of a dog developing coat changes.

Module-based complexity formation: periodic patterning in feathers and hairs

Patterns describe order which emerges from homogeneity. Complex patterns on the integument are striking because of their visibility throughout an organism’s lifespan. Periodic patterning is an effective design because the ensemble of hair or feather follicles (modules) allows the generation of complexity, including regional variations and cyclic regeneration, giving the skin appendages a new lease on life. Spatial patterns include the arrangements of feathers and hairs in specific number, size, and spacing.We explorehowa field of equivalent progenitor cells can generate periodically arranged modules based on genetic information, physical–chemical rules and developmental timing. Reconstitution experiments suggest a competitive equilibrium regulated by activators/inhibitors involving Turing reaction-diffusion. Temporal patterns result from oscillating stem cell activities within each module (microenvironment regulation), reflected as growth (anagen) and resting (telogen) phases during the cycling of feather and hair follicles. Stimulating modules with activators initiates the spread of regenerative hair waves, while global inhibitors outside each module (macroenvironment) prevent this. Different wave patterns can be simulated by cellular automata principles. Hormonal status and seasonal changes can modulate appendage phenotypes, leading to ‘organ metamorphosis’, with multiple ectodermal organ phenotypes generated from the same precursors. We discuss potential novel evolutionary steps using this module-based complexity in several amniote integument organs, exemplified by the spectacular peacock feather pattern. We thus explore the application of the acquired knowledge of patterning in tissue engineering. New hair follicles can be generated after wounding. Hairs and feathers can be reconstituted through self-organization of dissociated progenitor cells.

Tuning Wnt signals for more or fewer hairs

Activation of β-catenin was shown to be of central importance for hair development and cycling. Recent progress brought more understanding to how Wnt signaling is regulated during hair follicle generation and regeneration, telogen-anagen reentry, and extra-follicular macro-environmental modulation. This new understanding presents multiple possibilities to fine tune Wnt signaling for desired hair growth.

Evidence for genetic variation in human mate preferences for sexually dimorphic physical traits

Intersexual selection has been proposed as an important force in shaping a number of morphological traits that differ between human populations and/or between the sexes. Important to these accounts is the source of mate preferences for such traits, but this has not been investigated. In a large sample of twins, we assess forced-choice, dichotomous mate preferences for height, skin colour, hair colour and length, chest hair, facial hair, and breast size. Across the traits, identical twins reported more similar preferences than nonidentical twins, suggesting genetic effects. However, the relative magnitude of estimated genetic and environmental effects differed greatly and significantly between different trait preferences, with heritability estimates ranging from zero to 57%.