In vivo tomographic characterization of skin chromophore based on hyperspectral imaging.

Effects of dietary oxidized rice bran on the coloration, antioxidant capacity, and immunity in channel catfish (Ictalurus punctatus)

PurposeThis study aimed to evaluate iris melanin concentration using polarization-sensitive anterior segment optical coherence tomography (PS-AS-OCT) and to explore its correlation with iris color in individuals with brown irides.MethodsIris cross-sectional images were acquired using PS-AS-OCT. Substructural layers were automatically segmented using a deep learning model. The melanin concentration ratio (MCR) was derived from entropy-based PSAS-OCT images to quantify melanin within the iris layers. Iris surface color was analyzed using CIE L*a*b* values from high-resolution photographs. Correlation analyses were performed between MCR and L*a*b* values. Additionally, a three-grade iris color classification was used, and K-nearest neighbors (KNN) modeling assessed the predictive value of MCR.ResultsEighty-eight participants (mean age: 39 years) were included. MCR of the iris stroma showed a strong negative correlation with iris color: L* (r = 0.72), a* (r = -0.56), and b* (r = -0.68), all P < 0.001. Stromal MCR significantly differed among color grades (P < 0.001), and the KNN model achieved 85% classification accuracy.ConclusionsPS-AS-OCT-derived stromal MCR is strongly associated with iris color and offers a noninvasive approach for evaluating iris melanin. This technique may provide new insights into ocular pigmentation.

A case of seemingly progressive color dilution is documented in a male White-necked Jacobin Florisuga mellivora observed over a 16-month period in the southwestern Andes of Ecuador. In the earliest photographic records, the individual exhibited a noticeably lighter coloration, consistent with a pastel dilution-type chromatic aberration. This appearance was maintained for several months, but in more recent observations, the plumage shows a darker tone, possibly associated with a higher concentration of melanin. This variation has been interpreted as a gradual change in pigmentation, although it is acknowledged that the progressive nature of the process still requires further evaluation. Its persistence in the same locality, despite its high conspicuousness and repeated aggression by conspecifics, suggests that continuous access to food at artificial feeders may support its survival. This new record underscores the importance of long-term monitoring and provides valuable insights into the ecological and behavioral dynamics of atypical hummingbirds in anthropogenic environments, opening new avenues of research on their long-term adaptation and survival.

We investigate the impact of melanin concentration CMel and photoplethysmography (PPG) sensor configuration on signal quality and estimation accuracy of oxygen saturation mathrm {SpO_2}. We deploy Monte Carlo (MC) simulations of photon-skin interactions to estimate arterial oxygen saturations mathrm {SaO_2} ranging from 70 to 100% and melanin concentration CMel ranging from 2.55 to 30.5%. We analysed the effects of red and infrared wavelengths (624 nm, 660 nm, 850 nm, and 940 nm), beam profiles (LED and VCSEL), as well as beam incidence angles of light sources (0°, 45°, and − 45°) on Perfusion Index (PI), reflective mathrm {SpO_2} estimation, and signal-to-noise ratio (SNR) for source-detector distances ranging from 2 mm to 9 mm. Maximum PI was observed for in the red spectral range at 624 nm and in the infrared spectral range at 940 nm. In contrast, reflective pulse oximetry provided more accurate results at 660 nm and 850 nm, independent of wavelength combination. We conclude that the VCSEL beam profile at 0° is the optimal light source for a wide range of applications, as it offers a balance between PI and absolute mathrm {SpO_2} estimations error.

Background: Long non-coding RNAs (LncRNAs) represent a subset of genetic material exceeding 200 base pairs that lack protein-coding capacity, yet possess the unique capability to modulate gene expression. This study was conducted with the purpose of identifying the expression levels of LncRNA SIRT-1, LncRNA MCH, as well as the serum levels of IL-17, IL-33, and IFNγ in individuals with vitiligo. Furthermore, the investigation aimed to explore the potential correlation between long non-coding RNA and the parameters of study. Methods: The investigation was carried out on a cohort consisting of 30 patients with Generalized Vitiligo (GV) - both treated and untreated, 30 patients with Segmented Vitiligo (SV) - also both treated and untreated, and 25 Healthy Controls (HC). Using ELISA, the serum levels of IL-17, IL-33, IFNγ, SIRT 1, and PMCH were measured. Additionally, a gene expression analysis of long non-coding RNA (LncRNA) SIRT-1 and LncRNA PMCH was conducted in patients with GV and SV in order to shed light on their potential implications in the pathogenesis of vitiligo. Results: LncRNA SIRT-1 expression was significantly higher in GV compared to SV (p=0.030, Mann-Whitney test), with mean expression levels of 2.851 (SE: 1.052) and 0.507 (SE: 0.134), respectively. In contrast, no significant difference in LncRNA MCH expression was observed between the two vitiligo types. Conclusion: After investigation of the association between lncRNA expression of the SIRT1 and MCH genes and their corresponding serum concentrations in vitiligo patients, this research elucidated the dysregulated manifestations of LncRNA SIRT-1 and LncRNA MCH in individuals diagnosed with vitiligo, indicating their potential contributions to the etiology of vitiligo. This mechanism could involve the down regulation of serum SIRT-1 and MCH, as well as the elevation of cytokines. `

In this work, two types of Staphylococcus epidermidis fermentation broth were prepared in beef-protein medium and beef-protein medium with glucose, named as SFB and Glu-SFB. As a positive control, 0.5 mg/mL kojic acid was utilized, which led to a 33.1 ± 1.32 % drop in melanin content and a 30.9 ± 2.95 % reduction in tyrosinase activity in B16-F10 cells. After treatment with SFB and Glu-SFB, the intracellular melanin content diminished by 35.4 ± 0.67 % and 48.5 ± 1.36 %, while tyrosinase activity declined by 59.1 ± 1.49 % and 64.4 ± 2.03 %, respectively. The two S. epidermidis fermentation broth markedly diminish intracellular melanin concentrations and tyrosinase activity, leading to a whitening effect. The whitening efficacy of Glu-SFB surpasses that of SFB and exceeds that of 0.5 mg/mL kojic acid. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with untargeted metabolomics analysis was utilized to identify differential metabolites. Six oligopeptides were identified as Trp-Phe-Tyr-Leu (WFYL), Gln-Ile-Gly-Pro (QIGP), Val-Arg-Phe-Ile (VRFI), Tyr-Ile-Arg (YIR), Glu-Gln-Ile-Trp (EQIW), and His-Gly-Tyr-Lys (HGYK), exhibiting greater relative abundance in Glu-SFB than in SFB. At a dosage of 0.1 mg/mL, oligopeptide exhibits a greater capacity to diminish intracellular melanin levels and tyrosinase activity compared to 0.5 mg/mL kojic acid. Gly-SFB is prepared by replacing glucose with glycerol, the relative concentration of oligopeptides in Gly-SFB is positioned between that of SFB and Glu-SFB, while its whitening efficacy is similarly intermediate between SFB and Glu-SFB. Western blot research shown that all the S. epidermidis fermentation broths may suppress the expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), tyrosinase-related protein-2 (TRP-2), and microphthalmia-associated transcription factor (MITF), which is the primary mechanism underlying the whitening impact of these broths.

Comprehensive analysis of anatomical sites for transcutaneous bilirubin measurements in neonates using Monte Carlo multi-layered simulations.

This study uses COMSOL Multiphysics to create an optical model incorporating layered skin structures to investigate the impact of melanin concentration on light absorption characteristics at red and infrared wavelengths. The dynamic calibration algorithm is proposed to enhance measurement accuracy. Simulation results show that under high melanin concentrations, red light transmission intensity decreases by 23.5%, leading to an R-value deviation of 6.8%. By integrating the Individual Typology Angle for skin tone quantification and applying multiple linear regression, the root mean square error (RMSE) is reduced from 5.44% to 1.2%. This research provides theoretical support for optimizing optical design and skin-tone calibration in pulse oximeters, contributing to improved health monitoring equity for darker-skinned populations.

The objective of this experiment was to investigates effects of inclusion of black soldier fly larvae (BSFL) on growth performance, relative organ weight, and meat quality of broiler chickens. A total of 180 1-d-old broiler chickens were randomly allotted to 1 of 3 dietary treatments with 5 replicates. Each replicate consisted of 12 birds. Experimental diets were formulated to contain full-fat BSFL at inclusion levels of 0 %, 1 %, and 2 %. These diets were provided on an ad libitum basis for 5 wk. Results indicated that birds fed diet containing 1 % BSFL had greater (P < 0.05) feed efficiency than those fed diets containing 2 % BSFL. However, BW gain and feed intake of broiler chickens were not affected by increasing inclusion levels of BSFL in diets. Increasing inclusion levels of BSFL in diets showed a quadratic relationship (P < 0.05) with relative thymus weight. For meat color, values for redness (a*) and yellowness (b*) were decreased (linear, P < 0.05) as BSFL inclusion level of diets increased. Thiobarbituric acid reactive substance decreased (quadratic, P < 0.05) with increasing inclusion levels of BSFL in diets. Melanin concentrations in breast meat and liver characteristics were not affected by increasing inclusion levels of BSFL in diets. Increasing concentrations of BSFL in diets increased myristic acid concentrations (linear, P < 0.01) and eicosapentaenoic acid concentrations (linear, P < 0.05) in breast meat. These results suggest that dietary supplementation of BSFL has positive effects on immune organ weight, breast meat quality, and fatty acid compositions in breast meat. Therefore, BSFL can be used as a feed ingredient for broiler chickens. Also, we suggest that dietary supplementation of 1 % BSFL improves the performance and health of broiler chickens.

Skin tone bias in pulse oximetry is frequently reported to lead to overestimation of arterial blood oxygen saturation ( ) in individuals with darker skin tones. We introduce clinically applicable, skin tone corrected pulse oximetry models to address this disparity and promote more equitable patient care. We aim to mitigate skin tone bias in pulse oximetry by integrating a melanin correction factor into the conventional ratio-of-ratios approach. We employ pulsatile Monte Carlo simulation to systematically map the "ratio of ratios" ( ) to across varying melanin concentrations, thereby enabling comprehensive quantitative assessments of different correction models. A six-layered skin model is implemented to approximate the microstructure of human skin, allowing diffuse reflectance computations through Monte Carlo methods. Pulsatile effects are captured by modeling diastolic and systolic phrases, facilitating the calculation of values under diverse and melanin conditions. Skin tone induced error is quantified and mitigated by incorporating a melanin correction factor into conventional ratio-of-ratios. The inclusion of a melanin-dependent variable results in a substantial reduction in skin tone bias. Monte Carlo simulations offer precise control over both melanin content and , conditions that are challenging to replicate in vivo, and enable the development of robust correction models. These findings represent a valuable step toward more equitable pulse oximetry practices, ultimately improving patient care across diverse skin tones.

Oral and intralesional tranexamic acid (TXA), used in melasma treatment, pose systemic and invasive risks, while topical TXA suffers from poor permeability (logP = -1.6) and retention. The current study aimed to develop a topically effective polymeric micelles (PMs) based product incorporating 5% w/v TXA for deeper skin permeation and efficient melanocyte targeting. Developed PMs were novel in terms of: (i) composition, (ii) high drug loading of 250% with respect to the polymeric matrix, and (iii) transparent system. TXA-PMs had a particle size of 47.0 ± 3.6 nm, exhibited an entrapment efficiency of 81 ± 1.4%, and were transformed into a hydrogel (Hgel) for better skin retention by incorporating 0.5% Carbopol 934P. TXA-PMs Hgel had a pH of 5.7 and demonstrated favorable Newtonian pseudoplastic behavior, diffusion-controlled Higuchi release (>97%) up to 48 h, enhanced skin permeation (93% versus 74% observed with the marketed product), and retention (160% versus marketed product). On the other hand, free TXA in the Hgel matrix and the marketed product were released within 8 h. Three tier safety of TXA-PMs Hgel was demonstrated in in vitro cytotoxicity, in vivo acute toxicity, and biocompatibility tests. It substantially reduced melanin concentration (>50% inhibition) in B16F10 melanoma cell lines in comparison to free TXA Hgel (34%). The accelerated stability studies (6 months) revealed no significant change in the prepared formulations. TXA-PMs Hgel thus offers a promising therapeutic approach for melasma treatment as indicated by its enhanced permeation, stay in skin, and significant reduction in melanin content. Further, the production method is simple, industry amenable, and scalable.

The aim of the current investigation is to study the embryogenesis of the pseudobranchia (PB) in the Eastern mosquito fish Gambusia holbrooki, Girard, 1859 (Cyprinodontiformes, Poeciliidae). Histological sections from 2-4 mm long embryos revealed the presumable PB as a cell mass surrounded by a row of squamous cells in the operculum, as well as the formation of cartilage and blood vessels, and the beginning of the formation of its lamellae. In 5-7.75 mm long embryos, a prominent rise appeared in the mass of cells and PB lamellae, along with an increase in melanin deposition around the blood vessels. Moreover, a row of squamous cells encircled the rise from the front and back. At this stage, the parallel arrangement of the cartilage-attached lamellae correlated with increased melanin concentration around the blood vessels. In newborns, the differentiated cells increased similar to that appearing in the adult’s stages.

.SignificanceCurrent paradigms for the optical characterization of layered tissues involve explicit consideration of an inverse problem which is often ill-posed and whose resolution may retain significant uncertainty. Here, we present an alternative approach, structured light imaging mesoscopy (SLIM), that leverages the inherent sensitivity of raw spatial frequency domain (SFD) reflectance measurements for the detection of embedded subsurface scattering changes in tissue.AimWe identify wavelength–spatial frequency () combinations that provide optimal sensitivity of SFD reflectance changes originating from scattering changes in an embedded tissue layer. We specifically consider the effects of scattering changes in the superficial dermis which is a key locus of pathology for diverse skin conditions such as cancer, aging, and scleroderma.ApproachWe used Monte Carlo simulations in a four-layer skin model to analyze the SFD reflectance changes resulting from changes in superficial dermal scattering across wavelength ( to 851 nm) and spatial frequency ( to 0.5/mm). Within this model, we consider different values for epidermal melanin concentration to simulate variations in skin tone.ResultsMonte Carlo simulations revealed that scattering changes within the superficial dermis produce SFD reflectance changes which are maximized at specific () pairs and vary with skin tone. For light skin tones, SFD reflectance changes due to scattering reductions in the superficial dermis are maximized at and spatial frequency . By contrast, for darker skin tones, maximal SFD reflectance changes occur at wavelengths in the near-infrared () at a spatial frequency of . Interestingly, the change in SFD reflectance produced by such scattering changes is most uniform across all skin tones when using the longest wavelength tested () and a spatial frequency of . Taken together, our computational model identifies specific () pairs to optimally detect embedded structural alterations in the superficial dermis.ConclusionsThe findings establish the SLIM methodology as a means to detect morphological changes in an embedded subsurface tissue layer by leveraging inherent sensitivities of spatial frequency domain reflectance. This approach promises to enable simplified clinical tracking of subsurface microstructural alterations without the explicit need to consider an inverse problem approach.

Melanin is ubiquitous in nature, and how the arrangement and concentration of melanin affect its optical and thermal properties aids in understanding the role of melanin in natural systems and technological applications. In this study, a model system consisting of silica and melanin particles with different compositions and degrees of mixing is designed to study the impact on light absorption. The structures are generated using coarse‐grained molecular dynamics simulations, and their optical properties were calculated using finite‐difference time‐domain simulations. The results show that the supraballs with uneven distribution of melanin particles (strongly demixed) exhibit higher absorption (in the range of 360–1000 nm) at melanin concentrations of 40%–80%. Even for a simulation box with a thickness of 16 μm, the strongly demixed samples with melanin concentrations of 50%–100% absorb almost 80% of the total input light at 360–1000 nm. Since light absorption also correlates with thermal heat, thermal heat maps are presented for these systems as a function of melanin concentration and particle distribution. The fundamental knowledge of how melanin distribution alters power absorption will inform the development of photothermally responsive materials for medical applications (photothermal agents), sensors/communication devices, and coatings.

Abstract Introduction: Melanin deposition in the kidney is rare and appears to be limited to the conditions of malignant melanoma with melanuria and oculocutaneous (OCA) albinism. Melanin is generally an insoluble polymer, and it is curious how people with albinism who have little or no skin pigmentation can secrete melanin into the bloodstream, have it pass through the glomerular filtration barrier, and be absorbed by renal tubules. Methods: The concentration and solubility of melanin were analyzed in kidney tissue and urine of a renal transplant donor who had a pre-nephrectomy biopsy performed on a black kidney. Genetic testing of a donor blood sample found a novel homozygous Hermansky-Pudlak syndrome (HPS) HPS1 mutation (c.70G &gt; T; p.Glu24Ter). Melanin was extracted from a 24-hour urine collection, and tissue and urine melanin concentrations were determined by spectrophotometry. Results: In the kidney, non-melanosomal melanin was deposited as fine granules in the proximal tubular epithelium and as large aggregates within macrophages in renal tubular lumens. The kidney melanin concentration was 2 mg/g of tissue. Urine melanin was mainly water-soluble, with an excretion of 54 µmol of melanin per mmol of creatinine. Conclusions: Water-soluble melanin was excreted in the urine of an indiviual with a novel HSP1 mutation predicted to produce a truncated protein. The kidney showed no apparent short-term effect, but HSP can be associated with kidney, colon, and lung pathology, and the long-term outlook for the recipient's kidney and donor’s health is uncertain.

To assess the distribution of depolarization and its association with demographic and ocular biometric factors, we used polarization-sensitive anterior segment optical coherence tomography (PS-AS-OCT), to investigate the characteristics of the iris pigment epithelium (IPE) in healthy eyes. A group of 105 healthy Japanese adults participated in this study, and PS-AS-OCT images were captured for both eyes. The IPE depolarization region was segmented from the horizontal scan of the left eye images. The measurement of depolarization was determined by assessing two parameters: the height of the IPE depolarization region in the grayscale entropy image and the melanin concentration rate in the color entropy image. To investigate the distribution of depolarization, the segmented region was evenly divided into 99 fractions. This division was then evaluated at various locations within the IPE depolarization region using the depolarization parameters. Subsequantly, we analyzed the values obtained in relation to demographic and ocular biometric factors. Such factors include age, gender, axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), and lens thickness (LT). A total of 105 patients (age 39 ± 11yrs) fulfilled the inclusion criteria, including 84 males and 21 females. The height of the IPE depolarization region increased in both the pupillary and peripheral regions, while it remained stable in the midzone region. The distribution of melanin concentration rate exhibited a smooth pattern, with a decrease observed only in the periphery. Furthermore, the height of IPE depolarization in the peripheral region was found to be negatively correlated with AL and ACD, but positively correlated with LT, while the melanin concentration rate of specific points in mid-peripheral region was negatively correlated with AL (P < 0.05). By observing the distribution of IPE melanin-related depolarization in vivo though PS-AS-OCT, we identified the association between depolarization parameters and biometric factors AL, ACD and LT. This comprehensive baseline of the IPE depolarization parameters in healthy Japanese adults may offer valuable insights, especially in the context of pathological conditions.

To evaluate the changes of skin surface parameters in a patient with vitiligo using Antera 3D® Skin Image Analysis System, and to observe the clinical efficacy of the treatment of facial vitiligo. A patient with facial vitiligo was treated with intradermal injection of psoralen solution into the lesion combined with 308nm excimer laser therapy. Vitiligo lesion images were captured using the Antera 3D® camera before treatment and every 2 weeks after the start of the treatment. The associated software analysis system was used to measure the parameters of melanin level, ultra-low melanin concentration, and L* value as objective indexes for the evaluation of vitiligo treatment efficacy. After 10 treatments, the melanin level of the patient's skin lesions increased from 0.480 to 0.580, while the ultra-low melanin concentration and L* value decreased from 9.360 to 64.10 to 3.032 and 58.10, respectively. The Antera 3D® skin image analysis system provides objective data, which are conducive to improving patients' treatment compliance and confidence, as well as facilitating the development of treatment plans.

Protection of seeds from ionizing radiation is an important future need in space travel. We examined the usefulness of eumelanin from the fungus Gliocephalotrichum MTCC 5489 for this purpose. Seeds of Oryza sativa, Brassica nigra, Vigna radiata and V. aconitifolia were enclosed in Petri dishes coated with paint containing various concentrations of nanomelanin and exposed to doses of 0.1 to 2.0 kGy Cs-137 or 0.1 to 0.5 kGy Co-60 radiation. While Cs-137 radiation severely affected the rate of germination (germination index, GI) and germination percentage of Oryza sativa, whereas other seeds were less affected, Co-60 markedly diminished the GI of all the seeds. Increasing concentrations of melanin coating afforded significant protection to the GI of O. sativa seeds exposed to Cs-137 and to all seeds exposed to Co-60 radiation. The germination percentage of seeds was dose- and radiation dependent, with no effect observed for all doses of Cs-137 or 0.1 kGy Co-60 radiation, whereas 0.5 kGy Co-60 radiation killed 50 to 60% of the unprotected seeds. Melanin paint offered nearly 100% survival. This study demonstrated that melanin-containing materials can provide effective shielding from gamma radiation for diverse types of seeds that are important for human consumption, which has implications for space agriculture and agriculture in extreme environments.

This study investigates the incorporation of melanin extracted from pecan nutshell residues into a polyacrylonitrile (PAN) matrix during the electrospinning of microfiber membranes. Melanin concentrations of 0.5, 2.0, and 5.0% w/w were incorporated to enhance the physicochemical and biological properties of the fibers. The melanin-loaded PAN fibers exhibited significant antioxidant activity against DPPH and ABTS radicals, with scavenging rates ranging from 46.58% to 62.77% and 41.02% to 82.36%, respectively, while unmodified PAN fibers showed no activity. Furthermore, the melanin-loaded membranes demonstrated antimicrobial effects. The membranes also exhibited an important enzyme inhibition activity against collagenase (37%), hyaluronidase (22%), tyrosinase (36%), and elastase (33%). Molecular docking studies reveal different potential amino acids of the active sites of aging enzymes that interact strongly with melanin pigment, particularly collagenase, followed by hyaluronidase, tyrosinase, and elastase. These results suggest that the novel melanin-loaded PAN membranes possess promising bioactive properties with potential applications in different skin-care applications.