Natural Skin Color Research Articles

Effects of Chemical and Herbal Disinfection Methods on the Color Stability of Maxillofacial Silicone: An In Vitro Study

ABSTRACT Introduction: Maxillofacial prostheses used in rehabilitation of patients are fabricated with medical grade silicone and are tinted corresponding to the patients natural skin color. However, exposure to environment and disinfectants can affect the color stability. Due to rising microorganism resistance and fewer adverse effects of chemical agents, phytoextracts appear to be a viable option. This study aimed to evaluate the effects of two different disinfection methods one containing the leaf extracts of Mangifera indica (M. indica) and another containing 2% chlorhexidine solution on the color stability of precolored and hand-colored maxillofacial silicones. Material and Methods: Twenty specimens each of precolored and hand-colored silicone were randomly divided into four groups (n = 10) and cleansed with two different disinfection methods. Disinfection was carried out six times/day for 60 days, simulating once-a-day disinfection for a year. Color evaluation was carried out at day 0 and day 60 using a UV-vis spectrophotometer. Color alterations were calculated by the CIE L*a*b* system. Data were analyzed by two-way ANOVA with post hoc Tukey HSD and t-tests (α = 0.05). Result and Conclusion: In our study, 2% chlorhexidine solution resulted in the higher color change as compared to M.indica extract. Precolored silicone showed higher color stability than its hand-colored counterpart.

Towards equitable reporting of Indigenous status, ethnicity, language and country of birth in Australian paediatric clinical studies: A scoping review.

This scoping review aims to expansively review the reporting of Indigenous status, ethnicity, culture, language and country of birth in Australian paediatric clinical studies. Scoping review of Australian clinical studies, including randomised controlled trials, non-randomised controlled trials, cluster randomised controlled trials and quasi-experimental studies, with paediatric participants (<18 years) or mixed adult and paediatric participants. PubMed, Cumulated Index to Nursing and Allied Health Literature and Embase databases were searched for clinical studies published 1 January 2018 to 28 November 2022. Of the 2717 studies identified in the search, 209 clinical studies were included. Overall, 131 (62.7%) clinical studies captured in this review did not report any of the variables of interest. When reported, terms used by study authors varied extensively and subsequently five study-defined categories emerged 'Indigenous status', 'race', 'race and ethnicity', 'ethnicity', or 'natural skin colour'. 'Indigenous status' was most reported (n = 37, 17.7%), followed by 'ethnicity and/or cultural background' (n = 15, 7.2%), 'race and ethnicity' (n = 4, 1.9%), race (n = 1, 0.5%) and 'natural skin colour' (n = 1, 0.5%). Furthermore, language used at home was reported in 27 studies (12.9%) and country of birth in 23 studies (11.0%). This review demonstrated very low reporting of Indigenous status, ethnicity, culture, language and country of birth in Australian paediatric clinical studies. Poor reporting has raised concerns surrounding generalisability of findings from these trials in addition to equity. The recent international shift encompassing improved clinical trial reporting requirements, for ethnicity and race, require prompt establishment in the Australian clinical trial domain.

Reporting Indigenous status, ethnicity, language and country of birth to build equity in international paediatric clinical trials with Australian sites: a scoping review.

ObjectiveEnsuring equitable access to clinical trials for children from Indigenous and ethnically and linguistically diverse backgrounds should be central to clinical trial design. This review aims to expansively review the reporting of Indigenous status (Aboriginal and/or Torres Strait Islander origin), ethnicity, culture, location, language and country of birth in paediatric clinical trials with Australian sites.MethodsThis scoping review systematically searched PubMed, CINAHL and Embase for international clinical trials with Australian sites conducted between 2018 and 2022 involving children (aged <18years) to determine the reporting of Indigenous status, race, ethnicity, language and country of birth.ResultsOf the 262 studies included, 154 (58.8%) clinical trials did not report any of the variables of interest. When reported, terms used by authors were heterogeneous. 'Indigenous status' was most reported (n=40, 15.3%) and self-identification was the most common method to determine this (n=14, 35.9%). International clinical trials had higher rates of reporting for ethnicity, cultural background and race. Overall, more than 60 terms were used to categorise study participants in relation to 'Indigenous status', 'ethnicity and cultural background', 'race', 'race and ethnicity' or 'natural skin colour'.ConclusionsThis review demonstrated low rates of reporting of demographic variables in paediatric clinical trials. Clear reporting standards, partnering with consumers to co-design trials and self-identification during collection are required. Ensuring adequate access to clinical trials for Indigenous children and children from ethnically, linguistically and geographically diverse backgrounds is essential in building health equity and ensuring patient safety.

Investigating the robustness of the AlignRT InBore™ co-calibration process and determining the overall tracking errors

ObjectiveTo determine the overall tracking errors inherent to the co-calibration procedure of AlignRT InBore™’s (Vision RT Ltd., London, UK) ceiling-mounted and ring-mounted cameras. MethodsExtrinsic calibration errors related to the mismatch between ceiling and InBore cameras’ isocentres and treatment isocentre were determined using MV images and the SRS package and compared to traditional plate-based error. Next, using a realistic anthropomorphic female phantom, intrinsic calibration errors were determined while varying source-skin distance (80 to 100 cm), breast board inclination (0° to 12.5°), room lighting conditions (0 to 258 lx), skin colour (dark, white and natural skin colour), and pod occlusion. ResultsMV images of the cube proved plate-based calibration to suffer from large errors especially in the vertical direction (up to 2 mm). Intrinsic calibration errors were considerably lower. Indeed, RTD values of ceiling and InBore cameras showed little variability with isocentre depth (within 1.0 mm/0.4°), surface orientation and breast board inclination (within 0.7 mm/0.3°), changing lighting conditions (within 0.1 mm/0.2°), skin colour/tone (within 0.3 mm/0.3°) and camera pod occlusion (within 0.3 mm/0.2°). ConclusionThe use of MV-images proved critical to maintain co-calibrating errors of ceiling and InBore cameras to Halcyon’s treatment isocentre below 1 mm.

The Level of Surface Coverage of Surgical Site Disinfection Depends on the Visibility of the Antiseptic Agent-A Virtual Reality Randomized Controlled Trial.

Surgical site infections (SSIs) have a significant impact on outcome associated with surgical treatment. Therefore, skin antisepsis has evolved as a standard preoperative procedure in the operating room to reduce the perioperative risk of an SSI. In their "Global Guidelines for the prevention of surgical site infections", the World Health Organization (WHO) recommend the use of an agent with remanent additives and considers colored agents as helpful. However, colored and remanent disinfectants are not available in Germany. The aim of the present study was to investigate whether using a colored antiseptic solution increases the quality of preoperative skin antisepsis. This study was designed as a randomized, double-blinded controlled trial. To examine the level of coverage of skin antisepsis, an appropriate virtual reality (VR) environment was generated. Participants could see a movable surgical clamp with a swab in their hand. When touching the skin, the participants recognized an optical change in the appearance of the skin: Using a colored antiseptic solution resulted in orange-colored skin. Using an uncolored agent, a shiny wet look was visible without a change in natural skin color. Data of 141 participants (female: 61.0% (n = 86); mean age: 28 y (Range 18-58 y, SD = 7.53 y)) were included in the study. The level of disinfection coverage was higher in the group using the colored disinfectant. On average, 86.5% (sd = 10.0) of the leg skin was covered when a colored disinfectant was used, whereas only 73.9% (sd = 12.8) of the leg skin was covered when the participants had to use an uncolored agent (p < 0.001, effect size: f = 0.56, η2 = 0.24). The use of an uncolored disinfectant leads to a lower surface coverage of the perioperative skin disinfection. Thus far, it is unclear whether using uncolored disinfectants is associated with higher risks for perioperative infections compared with the use of non-remanent disinfectants. Therefore, further research is necessary and current German guidelines should be re-evaluated accordingly.

Development, Evaluation, and Comparison of an Indigenous ‘APDS’ AI-based Digital Application for Effective Shade Selection of Silicone Maxillofacial Prosthesis: Protocol for A Cross-sectional Study

Introduction: Reconstruction of maxillofacial defects is challenging in achieving aesthetic results. Replicating natural skin colour in maxillofacial prosthesis has been traditionally done using trial-and-error methods. However, with their respective limitations, multiple methods have been developed recently, like colourimeter and spectrophotometer. Need for the study: The natural appearance of the prosthesis affects the patient’s emotional and psychological well-being. Therefore, aesthetics is a prime concern now. So, the problem with colour matching of the maxillofacial prosthesis is profound. So, there is a need to develop customised shade guides and more advanced digitised shade-matching applications with Artificial Intelligence (AI) help. Therefore, a concoction of a customised silicon shade guide was contemplated with Advanced Programme in Data Sciences (APDS) AI-based digital application, and its reproducibility in clinical practice will be analysed. Aim: Phase 1- To develop and validate a customised broad spectrum silicon shade guide and APDS AI-based digital application on a survey of the Indian population. Phase 2- Comparative evaluation of the efficacy of indigenous APDS AI-based digital application with available shade guide systems for shade selection for silicone maxillofacial prosthesis. Methodology: A cross-sectional study. The shade guide will be fabricated with medical grade room temperature vulcanising silicone based on an observational survey. The shade guide will consist of three main groups ABC, divided into different subgroups from lighter to darker skin shades, and its accuracy evaluation is done by spectrophotometer. APDS AI-based digital application will be developed using reference from broadspectrum customised maxillofacial shade guide, and efficacy will be evaluated with visual assessment of colour matching by fabricating facial veneers for participants through investigators to investigate the consent of perfect colour match. Data will be statistically analysed.

Postinflammatory pigment changes.

After the skin is irritated or injured, the color of the skin can change. The skin may become darker or lighter than the natural skin color. This skin color change is called postinflammatory pigment alteration. The color change is temporary but can be worrisome for families.

Effects of Disinfection Methods on the Color Stability of Precolored and Hand-Colored Maxillofacial Silicone: An In Vitro Study.

Maxillofacial prostheses are used in rehabilitation of patients with facial defects. Typically, these prostheses are fabricated with medical grade silicone and are tinted corresponding to the patients' natural skin color. However, exposure to environment and disinfectants can result in color changes. This study aimed to evaluate the effects of four different disinfection methods on the color stability of precolored and hand-colored maxillofacial silicones. Forty specimens each of precolored and hand-colored silicone were prepared. The specimens were randomly divided into eight groups (n = 10) and cleansed with four different disinfection methods. Disinfection was carried out six times/day for 60 days, simulating once-a-day disinfection for a year. Color evaluation was carried out at day 0 and day 60 using a UV-vis spectrophotometer. Color alterations were calculated by the CIE L∗a∗b∗ system. Data were analyzed by two-way ANOVA with post hoc Tukey HSD and t-tests (α = 0.05). Disinfectants can affect the color stability of maxillofacial silicone. In our study, chlorhexidine solution and liquid soap resulted in the highest color change. Precolored silicone showed higher color stability than its hand-colored counterpart.

Effect of skin colors due to hemoglobin or melanin modulation on facial expression recognition

Facial color is thought to contribute to the perception of emotional expression. Previous studies on facial recognition have shown that reddish and bluish faces enhance the perceptions of anger and sadness, respectively. However, the effect of facial color on the recognition of facial expressions in the range of natural skin colors remains unexplored. In this study, we examined the effect of natural skin color changes on the perception of facial expressions of anger, sadness, and happiness. We used five skin color conditions for each facial expression: standard, and hemoglobin or melanin decrease/increase (H-, H+, M-, and M + ). In the experiment, we used images of different facial expressions ranging from neutral to maximum intensity. Observers judged whether a face stimulus was perceived as “angry” (“happy” or “sad”) or “not angry” (“not happy” or “not sad”). The results showed that H+, M+, H-, and M- enhanced the perception of anger and happiness, respectively. However, the change in the perception of sadness due to these modulations was small. These results suggest that the range of natural facial colors by hemoglobin and melanin modulation affects facial expression recognition. We further consider the possibility that these results could be partially explained by the lightness of the stimulus.

Clinical efficacy of dissolvable microneedles armed with anti-melanogenic compounds to counter hyperpigmentation.

Hyperpigmentation is a complex physiological process associated with alterations of skin color due to melanin overproduction and distribution. Both intrinsic and extrinsic factors influence discoloration with the involvement of multiple pathways in cooperative manners. Restoring natural skin color requires a multi-targeted approach. Latest advances in anti-melanogenic compounds and microneedle delivery system have presented opportunities for tackling hyperpigmentationsuccessfully. This work was aimed at assessing the dermal tolerability and efficacy of hyaluronic acid-based microneedle patches loaded with anti-melanogenic actives for improvements of skin discoloration. The test products consist of hyaluronic acid with niacinamide, ascorbic acid 2-glucoside, tranexamic acid, resveratrol, 4-n-butyl-resorcinol, and Halidrys siliquosa extract. In a monocentric 12weeks clinical trial, the HA-MNs patches were applied to the affected areas of the faces on subjects with hyperpigmented skin. The color properties of the skin were analyzed spectrophotometrically. The products were tolerated remarkably; none of the subjects informed any primary or cumulative skin responses. Evaluation of color related measurable skin properties provided insight into the general effectiveness: The individual topology measurements showed 51.4% noticeable improvements in hyperpigmented zones, which were also in good agreement with the personal impressions of the subjects determined by questionnaires before and after the treatments. The concentrated blends of actives in microneedle patches act in a multi-targeted manner, and they could be worked in a complementary fashion for the improvement of skin color and appearance. The study has established the overall convenience of the HA-MNs with the formulation of anti-melogenic compounds against skin discoloration.

694 An epidermal model containing melanocytes for skin pigmentation and lightening studies

Considerable interest exists in evaluating raw materials and/or skin care formulations which cause lightening of the skin. These products are utilized to modulate one’s natural skin color or to combat skin pigmentation disorders such as melasma, dark spots, solar lentigo, and other hyperpigmentation lesions. To aid in the development and testing of such products, we have developed a skin whitening protocol using the epidermal skin model, MelanoDerm™, to evaluate both raw materials and skin lightening formulations. MelanoDerm is a highly differentiated, three-dimensional tissue culture model of human epidermis that contains normal human melanocytes (NHM) and keratinocytes (NHK). Epidermal tissues have been produced containing NHM of varying skin phototypes which follow the pigmentation level of the donor tissue, i.e. black > Asian > Caucasian. For lightening studies, tissues were treated topically three times a week over a two to three week period to mimic consumer application. Several over-the-counter skin lightening products were evaluated in cultures containing NHM from black and Asian donors. Over the treatment period, negative control cultures became increasingly pigmented with retention of normal epithelial morphology. In contrast, tissues treated topically with cosmetic skin lightening agents containing tyrosinase inhibitors such as kojic acid and magnesium ascorbyl phosphate remained lighter than the control cultures. The skin lightening effect on treated tissues was quantitatively evaluated for melanin content using a Solvable melanin assay and for skin brightness (L* value) using a hand-held spectrometer. Treated tissues showed significant changes in overall melanin content and brightness compared to control tissues. These results suggest that this model can provide valuable in vitro data for screening raw materials prior to the commencement of costly clinical trials and that it will be useful to study melanogenesis, skin lightening, and other pigmentation phenomena of the skin.

Abstract 234: Understanding melanoma susceptibility through GWAS of risk phenotypes

Abstract Melanoma susceptibility SNPs can be categorized by their impact on known susceptibility phenotypes (pigmentation, nevus count, telomere length, or other). In an ongoing meta-analysis of melanoma, at this stage involving 17,800 cases but soon expanding to more than 30,000 cases, 26 SNPs have achieved genome-wide significance. UK Biobank is a population-based cohort of 500,000 UK persons aged at recruitment 40-69 years; participants reported pigmentation characteristics including ease of tanning, natural hair color, skin color (in the absence of tan), and number of childhood sunburns. To conduct analyses, we separately analyzed the red hair phenotype while ordering the other hair colors from black to blond. Among the 26 SNPs from the melanoma GWAS, 15 were associated with at least one pigmentation factor assessed in UK Biobank (each at p &amp;lt;10-5) with 5 being associated with all pigmentation factors (e.g., SLC45A2, ASIP, MC1R) while others were associated with a subset of factors (e.g., RAD23B/TAL2 was strongly associated with hair color alone). 13 of the melanoma SNPs were associated with "ease of tanning." Detailed analysis of "ease of tanning" SNPs found 29 genome-wide significant in a subset of UK Biobank, of which 13 were associated with melanoma risk (p &amp;lt;0.001) but notably 4 of the SNPs showed no evidence of melanoma risk even when being among the strongest effects for "ease of tanning" and the remainder showing weaker evidence of association. For all pigmentation factors (except having red hair), the effect sizes for a SNP on melanoma risk and pigmentation were highly correlated. We examined the 26 melanoma SNPs in recent GWAS of nevus count and telomere length, and similarly observed overlaps with these phenotypes. While the telomere, nevus and pigmentation instruments were largely distinct, we found evidence of some overlap in genetic susceptibility (for instance, the PLA2G6 SNP rs2092180 is strongly associated with nevus count, ease of tanning and skin color [all p &amp;lt;10-12]). Combined analysis of the melanoma GWAS results with the GWAS of each of these phenotypes provides overwhelming evidence of further susceptibility loci, indicating that GWAS of intermediate phenotypes can benefit identification of the underlying genetic profile. Supported by Cancer Research UK (C588/A19167) &amp; NIH (CA083115). This research has been conducted using the UK Biobank Resource. Citation Format: David T. Bishop, Mark M. Iles, Julia A. Newton-Bishop, Jennifer H. Barrett, Adam Trouwer, Matthew Law, Stuart MacGregor, David Duffy, Nicholas G. Martin, Nicholas Hayward, Anne Cust, Maria T. Landi, Alisa Goldstein, Jianxin Shi, Mitch Machiela, Florence Demenais, Peter Kanetsky, GenoMEL &amp; MELANOSTRUM. Understanding melanoma susceptibility through GWAS of risk phenotypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 234.

Effects of Mild Hyperthermia Treatment Using Nano-Mist Sauna on Blood Gas Parameters and Skin Appearance

Physicians often observe patients’ complexion (their natural skin color) as an indicator of health. The complexion may depend on the internal environment, however, very few researchers studied its evidence. We previously reported various benefits of a mild hyperthermia treatment on human health using the nano-mist sauna (NMS), including acceleration of gas exchange (O2 and CO2) in the venous blood, enhancement of immunity, and the modulation of autonomic nervous system. However, the effects of NMS on skin appearance are unknown. There is a historical and widespread belief that mild hyperthermic treatments such as hot springs are good for improving skin appearance. However, the effect of NMS on the skin appearance has not been examined. In the present study, we examined the color of venous blood using the CIELAB (a color space specified by the French Commission internationale de l’eclairage) method, and then compared the color changes before and after NMS stimulation. Next, we examined correlations of blood gas parameters with color elements of the venous blood, which are highly dependent on oxygen. Our results suggest that the colors and appearance of the face depend on the internal environment, because there are numerous vessels under the skin. Thus, the color of the venous blood may provide medical evidence of changes in complexion. This new method may be useful for assessment of medical complexion by physicians, for use in determining internal health based on skin color information.

Association of Sun Exposure, Skin Colour and Body Mass Index with Vitamin D Status in Individuals Who Are Morbidly Obese.

Vitamin D deficiency is a common issue, particularly in obese populations, and is tested by assessing serum 25(OH)D concentrations. This study aimed to identify factors that contribute to the vitamin D status in fifty morbidly obese individuals recruited prior to bariatric surgery. Data collected included serum 25(OH)D concentrations, dietary and supplement intake of vitamin D, sun exposure measures, skin colour via spectrophotometry, and genotype analysis of several single nucleotide polymorphisms in the vitamin D metabolism pathway. Results showed a significant correlation between serum 25(OH)D concentrations and age, and serum 25(OH)D and ITAC score (natural skin colour). Natural skin colour accounted for 13.5% of variation in serum 25(OH)D, with every 10° increase in ITAC score (i.e., lighter skin) leading to a 9 nmol/L decrease in serum 25(OH)D. Multiple linear regression using age, ITAC score, and average UV index in the three months prior to testing, significantly predicted serum 25(OH)D concentrations (R2 = 29.7%). Single nucleotide polymorphisms for all vitamin D genes tested, showed lower serum 25(OH)D for those with the rare genotype compared to the common genotype; this was most pronounced for fok1 and rs4588, where those with the rare genotype were insufficient (<50 nmol/L), and those with the common genotype were sufficient (≥50 nmol/L). Assessing vitamin D status in individuals with morbid obesity requires testing of 25(OH)D, but potential risk factors for this population include natural skin colour and age.

SOCIAL MEDIA AND THE CULTURAL IDEOLOGY OF BEAUTY AMONG YOUNG BLACK WOMEN IN SOUTH AFRICA

Celebrities and celebrity culture tend to influence young people’s ideas of culture and the aspirational perception of self and identity. With social media platforms increasingly becoming spaces of influence for celebrities, how do they use these platforms to communicate their perceptions of beauty and the feminine body, and what messages do they communicate in this manner? This articles reports on a study that explored the cultural ideology of beauty against the backdrop of a digital culture that draws on celebrity beauty performances on social media. Through non-participatory digital ethnographic observations on social media of four female South African celebrities and conversational interviews with young adults, the study examined how celebrities present their bodies in the performance of beauty on social media and explored the messages that pertain to feminine beauty amongst young women. The findings revealed that celebrity culture perpetuates the ideology that black beauty can be achieved through natural skin colour erasure, extended artificial weaves and a thin body frame.

CDC Grand Rounds: Prevention and Control of Skin Cancer

Skin cancer is the most common cancer in the United States, and most cases are preventable. Persons with certain genetic risk factors, including having a lighter natural skin color; blue or green eyes; red or blonde hair; dysplastic nevi or a large number of common moles; and skin that burns, freckles, or reddens easily or becomes painful after time in the sun, have increased risk for skin cancer. Persons with a family or personal history of skin cancer, especially melanoma, are also at increased risk. Although these genetic factors contribute to individual risk, most skin cancers are also strongly associated with ultraviolet (UV) radiation exposure. Most UV exposure comes from the sun, although some persons use UV-emitting indoor tanning devices (e.g., beds, booths, and lamps).

A Custom Made Intrinsic Silicone Shade Guide for Indian Population.

Replication of natural skin colour in maxillofacial prosthesis has been traditionally done using trial and error method, as concrete shade guides are unavailable till date. Hence a novel custom made intrinsic silicone shade guide has been attempted for Indian population. Reconstruction of maxillofacial defects is challenging, as achieving an aesthetic result is not always easy. A concoction of a novel intrinsic silicone shade guide was contemplated for the study and its reproducibility in clinical practice was analysed. Medical grade room temperature vulcanising silicone was used for the fabrication of shade tabs. The shade guide consisted of three main groups I, II and III which were divided based upon the hues yellow, red and blue respectively. Five distinct intrinsic pigments were added in definite proportions to subdivide each group of different values from lighter to darker shades. A total number of 15 circular shade tabs comprised the guide. To validate the usage of the guide, visual assessment of colour matching was done by four investigators to investigate the consent of perfect colour correspondence. Data was statistically analysed using kappa coefficients. The kappa values were found to be 0.47 to 0.78 for yellow based group I, 0.13 to 0.65 for red based group II, and 0.07 to 0.36 for blue based group III. This revealed that the shade tabs of yellow and red based hues matched well and showed a statistically good colour matching. This intrinsic silicone shade guide can be effectively utilised for fabrication of maxillofacial prosthesis with silicone in Indian population. A transparent colour formula with definite proportioning of intrinsic pigments is provided for obtaining an aesthetic match to skin tone.

CDC Grand Rounds: Prevention and Control of Skin Cancer.

Skin cancer is the most common cancer in the United States, and most cases are preventable. Persons with certain genetic risk factors, including having a lighter natural skin color; blue or green eyes; red or blonde hair; dysplastic nevi or a large number of common moles; and skin that burns, freckles, or reddens easily or becomes painful after time in the sun, have increased risk for skin cancer. Persons with a family or personal history of skin cancer, especially melanoma, are also at increased risk. Although these genetic factors contribute to individual risk, most skin cancers are also strongly associated with ultraviolet (UV) radiation exposure. Most UV exposure comes from the sun, although some persons use UV-emitting indoor tanning devices (e.g., beds, booths, and lamps).

Self‐reported skin colour and erythemal sensitivity vs. objectively measured constitutive skin colour in an African population with predominantly dark skin

Skin colour is an important factor in skin-related diseases. Accurate determination of skin colour is important for disease prevention and supporting healthy sun behaviour, yet such data are lacking for dark skin types. Self-perceived, natural skin colour and sun-skin reaction were compared with objectively measured skin colour among an African population with predominantly dark skin. Unexposed skin of 556 adults (70.1% Black) was measured with a reflectance spectrophotometer to calculate an individual typology angle (°ITA). Participants reported self-perceived skin colour and erythemal sensitivity. There was a strong, positive monotonic correlation between self-reported and measured skin colour (Spearman ρ=0.6438, P<0.001), but only a weak correlation between self-reported erythemal sensitivity and measured skin colour (Spearman ρ=0.2713, P<0.001). Self-report biases in underestimation and overestimation of skin colour were evident. Many participants with 'dark brown' and 'black' skin had difficulty in classifying erythemal sensitivity. In Africa, self-reported skin colour could potentially be used in lieu of spectrophotometer measurements, but options for questions on sunburn and tanning require suitable adjustment. Our study provides evidence of range in °ITA values among residents in Africa and reinforces previous results that self-report may be reliable for determining skin colour, but not erythemal sensitivity, for dark skin individuals.

Enzyme mediated beam house operations of leather industry: a needed step towards greener technology

Abstract Leather industries, due to pollution of water, careless disposal of solid wastes and gaseous emissions, are categorized as a red industry and are under deep pressure to develop environmentally efficient leather-making processes to comply with modern pollution and discharge legislation. In the present study, completely enzyme based beam house operations (dehairing & degreasing) of leather industry has been standardized for skins & hides using Bacillus licheniformis protease and Bacillus subtilis lipase. Owing to its immense importance and demand the productions of these enzymes were optimized and scaled up in a 300 L bioreactor resulting in a maximum yield of 4568 U/mL in 18 h for protease and 34.91 IU/mL of lipase in 36 h. 100% enzymatic dehairing & degreasing of skins and hides could be obtained at pH value of 8.0 and temperature 30–37 °C with the enzyme concentration of 2–5% (w/v) of protease for dehairing and 5–10% (w/v) of lipase for degreasing within 8–12 h. An interesting observation noted for enzyme based leather processing was that natural skin colour was preserved along with a drastic reduction of BOD and COD values of effluent. Crust leather formed using enzymatically processed skins exhibited similar physical and tactile properties as observed for conventional crust leather. On the bases of internally quenched fluorescent substrate specific method, this protease is subtilisin-like serine protease with low collagenase activity. High collagenase activity can damage the hide (leather) grain and the physical-mechanical characteristics of the hides. Successful demonstrations of large size (Industrial trials −100 kg skin/hide at Central Leather Research Institute, Chennai, India) 100% chemical free dehairing and degreasing further supports the authenticity of the work. Thus all this makes the beam house operations of leather tannery enzymatically feasible and environmentally benign.