Search Results (16)

This study presents a comprehensive evaluation and an equivalent circuit modeling of the skin–electrode impedance characteristics of three types of ultra-thin tattoo electrodes, all based on Parylene C nanofilms but with different active materials: Gold, Silver, and PEDOT:PSS. Their performance was compared to standard disposable Ag/AgCl electrodes. Impedance measurements were carried out on six human subjects under controlled conditions, assessing the frequency response in the range of 20 Hz to 1 kHz. For each subject, the impedance was recorded six times over one hour to investigate the stability and the temporal performance. The collected data were subsequently analyzed to model the electrical properties and interface behavior of each electrode type. The findings demonstrate that the tattoo electrodes offer impedance levels comparable to those of Ag/AgCl electrodes (in the order of tens of kΩ at 20 Hz), while providing additional benefits such as enhanced conformability, improved skin adhesion, and reduced skin irritation during use. Furthermore, the modeling of the skin–electrode interface through a more detailed equivalent circuit than the single time constant model enables a more detailed interface analysis and description, with fitting algorithm R² scores of about 0.999 and 0.979 for the impedance magnitude and impedance phase, respectively. The proposed equivalent circuit offers valuable insights for optimizing electrode design, supporting the potential of Parylene C-based tattoo electrodes as promising alternatives for next-generation wearable bioelectronic applications. Full article

Tattoo inks contain varying amounts of metal nanoparticles (NPs) < 100 nm that, due to their unique physicochemical properties, may have specific biological uptake and cause skin or systemic toxicities. The toxic effects of certified reference standards of metal NPs and samples of commercially available tattoo inks were investigated using an in vitro system and a novel human ex vivo model. In vitro toxicity was evaluated using vitality assays on human skin cells (HaCaT cell line, primary fibroblasts, and keratinocytes). No toxicity was observed for Al₂O₃, Cr₂O₃, Fe₂O₃, and TiO₂ NPs, whereas CuO NPs showed dose-dependent toxicity on HaCaT and primary fibroblasts. Fibroblasts and keratinocytes were also sensitive to high concentrations of ZnO NPs. Reference standards and ink samples were then injected ex vivo into human skin explants using tattoo needles. Histological analysis showed pigment distribution deep in the dermis and close to dermal vessels, suggesting possible systemic diffusion. The presence of an inflammatory infiltrate was also observed. Immunohistochemical analysis showed increased apoptosis and expression of the inflammatory cytokine interleukin-8 in explants specifically tattooed with the reference standard or red ink. Taken together, the results suggest that the tattooing technique leads to exposure to toxic metal NPs and skin damage. Full article

Background: Patients’ compliance to inhalation therapy is usually sub-optimal in young asthmatics. Adolescents poorly compliant to regular anti-asthma treatments and those with tattoos (and the associated attitude) can share some personality traits and maladaptive behaviors. This relationship has not been investigated. Objective: To assess if “extended” tattoos can predict long-term compliance to regular therapy of adolescents with mild-to-moderate asthma. Methods: A 12-month retrospective observational investigation was conducted on non-smoker asthmatic adolescents of both genders. Patients assuming <70% of prescribed vilanterol/fluticasone furoate o.d. were defined as “non-compliant”. Tattoo surfaces were defined as “mild” or “extended” if they were < or ≥400 cm², respectively. The relationship between tattoos and compliance on the evolution of resources consumption at 6 and 12 months was assessed by generalized estimating equation (GEE) models at the first and second semester of the treatment period. Results: It was found that 13.2% of compliant adolescents had mild tattoos, while 47.2% of non-compliant adolescents had mild-to-extended tattoos (odds ratio (OR) 6.91, 95% CI 2.49 to 19.17, p < 0.001). The mean annual adherence to treatment was 57.8% ± 10.1 SD expected doses in non-compliant subjects with “mild tattoos” (54.8 cm² ± 36.9 SD), but 38.6% ± 11.4 SD expected doses in those with “extended tattoos” (568.4 cm² ± 111.6 SD, p < 0.001). Total cost proved to be a linear trend from the lowest values of compliant patients with no/mild tattoos (EUR 65.22 at 6 months and EUR 33.63 at 12 months) to the highest values of non-compliant adolescents with extended tattoos (EUR 330.75 at 6 months and EUR 297.34 at 12 months). Conclusions: Tattoo extension might be used as a reliable predictor of poor compliance and higher health care costs in adolescents with mild-to-moderate asthma. Patients characterized by poor compliance to a long-term therapeutic strategy and tattooing attitude likely share some aspects of their personality profile. Full article

Hepatitis C virus (HCV) infection is among the leading causes of cirrhosis and hepatocellular carcinoma. Knowledge of its prevalence and risk factors can help to effectively fight the virus. This study was the first to investigate the seroprevalence of HCV, its genotypes, and factors associated with it among the general adult population of Armenia selected countrywide via cluster sampling. Anti-HCV antibodies were detected using third-generation immunoassay. Polymerase chain reaction and genotyping was performed among anti-HCV-positive individuals. Shortly after testing, the participants underwent a telephone survey. Logistic regression models were fitted to identify factors associated with anti-HCV antibody positivity and chronic HCV infection. The prevalence of anti-HCV antibodies among 3831 tested individuals was 2% (99% CI 1.4, 2.5), and chronic HCV infection was 0.7% (99% CI 0.4, 1.0), with genotypes 3 and 2 being the most common. The risk factors for chronic HCV infection included self-reported chronic liver disease (95% CI 1.47, 15.28), having tattoos (95% CI 1.34, 10.94), ever smoking (95% CI 1.16, 9.18), and testing positive for hepatitis B virus core antibody (95% CI 1.02, 7.17). These risk factors demonstrate that there could be room for strengthening infection control measures to prevent the transmission of HCV in Armenia. Full article

In breast cancer, Targeted Axillary Dissection (TAD) allows for the selective excision of the sentinel lymph node (SLN) during primary tumor surgery. TAD consists of the resection of labelled SLNs prior to neoadjuvant chemotherapy (NACT). Numerous clinical and preclinical studies have explored the use of carbon-based colloids for SLN tattooing prior to NACT. However, carbon vectors show varying degrees of inflammatory reactions and, in about one fifth of cases, carbon particles migrate via the lymphatic pathway to other nodes, causing the SLN to mismatch the tattooed node. To overcome these limitations, in this study, we explored the use of melanin as a staining endogenous pigment. We synthesized and characterized melanin-loaded polymeric nanoparticles (Mel-NPs) and used them to tattoo lymph nodes in pig animal models given the similarity in the size of the human and pig nodes. Mel-NPs tattooed lymph nodes showed high identification rates, reaching 83.3% positive identification 16 weeks after tattooing. We did not observe any reduction in the identification as time increased, implying that the colloid is stable in the lymph node tissue. In addition, we performed histological and ultrastructural studies to characterize the biological behavior of the tag. We observed foreign-body-like granulomatous inflammatory responses associated with Mel-NPs, characterized by the formation of multinucleated giant cells. In addition, electron microscopy studies showed that uptake is mainly performed by macrophages, and that macrophages undergo cellular damage associated with particle uptake. Full article

The large number of images in the different areas and the possibilities of technologies lead to various solutions in automatization using image data. In this paper, tattoo detection and identification were analyzed. The combination of YOLOv5 object detection methods and similarity measures was investigated. During the experimental research, various parameters have been investigated to determine the best combination of parameters for tattoo detection. In this case, the influence of data augmentation parameters, the size of the YOLOv5 models (n, s, m, l, x), and the three main hyperparameters of YOLOv5 were analyzed. Also, the efficiency of the most popular similarity distances cosine and Euclidean was analyzed in the tattoo identification process with the purpose of matching the detected tattoo with the person’s tattoo in the database. Experiments have been performed using the deMSI dataset, where images were manually labeled to be suitable for use by the YOLOv5 algorithm. To validate the results obtained, the newly collected tattoo dataset was used. The results have shown that the highest average accuracy of all tattoo detection experiments has been obtained using the YOLOv5l model, where mAP@0.5:0.95 is equal to 0.60, and mAP@0.5 is equal to 0.79. The accuracy for tattoo identification reaches 0.98, and the F-score is up to 0.52 when the highest cosine similarity tattoo is associated. Meanwhile, to ensure that no suspects will be missed, the cosine similarity threshold value of 0.15 should be applied. Then, photos with higher similarity scores should be analyzed only. This would lead to a 1.0 recall and would reduce the manual tattoo comparison by 20%. Full article

Permanent makeup (PMU) is a popular application for the correction of face and body imperfections. It can be applied over the facial area to correct the shape and color of eyebrows, to the eyelids to create permanent eyeliner shapes, and the lips to create permanent lipliner and lip shading features. Furthermore, its “medical” use on the scalp and men’s facial hair area to camouflage hair follicles and to cover hairless areas makes it popular for hair transplants. No matter how useful these procedures are, there are always mistakes and the factor of bad application which raises the number of patients who want to “remove” it or “correct” it on their face or body. In order to find a non-laser solution for PMU removal, we investigated the decolorization capacity of common plants and plant origin extracts on mouse models. Two methods were used for PMU decolorization. The first one included the use of traditional tattooing with needles combined with plant origin extracts applied over the tattooed area. The second one included the use of electroporation technology application with the combination of plant origin materials to remove the PMU colorants over the tattooed area. In both cases, the permanent makeup colorants for eyebrows, eyeliners, and lipliners were applied in vivo. Full article

Evaluation of the United States Centers for Disease Control and Prevention (CDC)-defined HCV-related risk factors are not consistently performed as part of routine care, rendering risk-based testing susceptible to clinician bias and missed diagnoses. This work uses natural language processing (NLP) and machine learning to identify patients who are at high risk for HCV infection. Models were developed and validated to predict patients with newly identified HCV infection (detectable RNA or reported HCV diagnosis). We evaluated models with three types of variables: structured (structured-based model), semi-structured and free-text notes (text-based model), and all variables (full-set model). We applied each model to three stratifications of data: patients with no history of HCV prior to 2020, patients with a history of HCV prior to 2020, and all patients. We used XGBoost and ten-fold C-statistic cross-validation to evaluate the generalizability of the models. There were 3564 unique patients, 487 with HCV infection. The average C-statistics on the structured-based, text-based, and full-set models for all the patients were 0.777 (95% CI: 0.744–0.810), 0.677 (95% CI: 0.631–0.723), and 0.774 (95% CI: 0.735–0.813), respectively. The full-set model performed slightly better than the structured-based model and similar to text-based models for patients with no history of HCV prior to 2020; average C-statistics of 0.780, 0.774, and 0.759, respectively. NLP was able to identify six more risk factors inconsistently coded in structured elements: incarceration, needlestick, substance use or abuse, sexually transmitted infections, piercings, and tattoos. The availability of model options (structured-based or text-based models) with a similar performance can provide deployment flexibility in situations where data is limited. Full article

Systems that analyse faces have seen significant improvements in recent years and are today used in numerous application scenarios. However, these systems have been found to be negatively affected by facial alterations such as tattoos. To better understand and mitigate the effect of facial tattoos in facial analysis systems, large datasets of images of individuals with and without tattoos are needed. To this end, we propose a generator for automatically adding realistic tattoos to facial images. Moreover, we demonstrate the feasibility of the generation by using a deep learning-based model for removing tattoos from face images. The experimental results show that it is possible to remove facial tattoos from real images without degrading the quality of the image. Additionally, we show that it is possible to improve face recognition accuracy by using the proposed deep learning-based tattoo removal before extracting and comparing facial features. Full article

Tattooing is a technique that introduces colored substances under the skin in order to color it permanently. Decomposition products of tattoo pigments produce numerous damages for the skin and other organs. We studied the effects of a commercial red ink tattoo, PR170, on Xenopus laevis embryos and Daphnia magna nauplii using concentrations of 10, 20, and 40 mg/L. For Xenopus, we applied the FETAX protocol analyzing survival, malformations, growth, heart rate, and the expression of genes involved in the development. In D. magna, we evaluated the toxicity with an immobilization test. Moreover, we investigated the production of ROS, antioxidant enzymes, and the expression of the ATP-binding cassette in both models. Our results indicate that PR170 pigment has nanoparticle dimensions, modifies the survival and the ATP-binding cassette activity, and induces oxidative stress that probably produces the observed effects in both models. Deformed embryos were observed in Xenopus, probably due to the modification of expression of genes involved in development. The expression of pro-inflammatory cytokines was also modified in this amphibian. We think that these effects are due to the accumulation of PR170 and, in particular, to the presence of the azoic group in the chemical structure of this pigment. Further studies needed to better understand the effects of commercial tattoo inks. Full article

Sak Yan Ontology (SYO) models knowledge derived from Thai tattoos in the design of cultural heritage preservation planning. Ontology Development 101 is a technique of ontology model creation. The aims of this study are to share the performance of ontology development and ontology evaluation. The study is specifically focused on validation from domain experts and automation evaluated using the OOPS! tools (OntOlogy Pitfall Scanner is a tool that helps detect some of the most common pitfalls appearing when developing ontologies). The results obtained from OOPS! show that SYO is devoid of critical errors; however, it does have one critical, three important, and three minor problems. Four of the problems are fixed, whereas the others are continuous. The combination of automatic and human validation methodologies improves the quality of the ontology being modeled. The tools enhance the traditional methodology with quicker, easier, and smaller amounts of subjective analysis. In conclusion, for the reparation movement, solutions for the above problems are suggested. Full article

Diseases of the kidney contribute a significant morbidity and mortality burden on society. Localized delivery of therapeutics directly into the kidney, via its arterial blood supply, has the potential to enhance their therapeutic efficacy while limiting side effects associated with conventional systemic delivery. Targeted delivery in humans is feasible given that we can access the renal arterial blood supply using minimally invasive endovascular techniques and imaging guidance. However, there is currently no described way to reproduce or mimic this approach in a small animal model. Here, we develop in mice a reproducible microsurgical technique for the delivery of therapeutics directly into each kidney, via its arterial blood supply. Using our technique, intra-arterially (IA) injected tattoo dye homogenously stained both kidneys, without staining any other organ. Survival studies showed no resulting mortality or iatrogenic kidney injury. We demonstrate the therapeutic potential of our technique in a mouse model of cisplatin-induced acute kidney injury (AKI). IA injection of mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) successfully reversed AKI, with reduced physiological and molecular markers of kidney injury, attenuated inflammation, and restoration of proliferation and regeneration markers. This reproducible delivery technique will allow for further pre-clinical translational studies investigating other therapies for the treatment of renal pathologies. Full article

Laser lights have been used by dermatologists for tattoo removal through photothermal interactions. However, most clinical studies used a visual scoring method to evaluate the tattoo removal process less objectively, leading to unnecessary treatments. This study aimed to develop a simple and quantitative imaging method to monitor the degree of tattoo removal in in vivo skin models. Sprague Dawley rat models were tattooed with four different concentrations of black inks. Laser treatment was performed weekly on the tattoos using a wavelength of 755 nm over six weeks. Images of non-treated and treated samples were captured using the same method after each treatment. The intensities of the tattoos were measured to estimate the contrast for quantitative comparison. The results demonstrated that the proposed monitoring method quantified the variations in tattoo contrast after the laser treatment. Histological analysis validated the significant removal of tattoo inks, no thermal injury to adjacent tissue, and uniform remodeling of epidermal and dermal layers after multiple treatments. This study demonstrated the potential of the quantitative monitoring technique in assessing the degree of clearance level objectively during laser treatments in clinics. Full article

There is increasing interest in the development of non-invasive tools for studying the properties of skin, due to the potential for non-destructive sampling, reduced ethical concerns and the potential comparability of results in vivo and in vitro. The present research focuses on the use of a range of non-invasive approaches for studying skin and skin barrier properties in human skin and human skin equivalents (HSE). Analytical methods used include pH measurements, electrical sensing of the epidermis and detection of volatile metabolic skin products. Standard probe based measurements of pH and the tissue dielectric constant (TDC) are used. Two other more novel approaches that utilise wearable platforms are also demonstrated here that can assess the electrical properties of skin and to profile skin volatile species. The potential utility of these wearable tools that permit repeatability of testing and comparability of results is considered through application of our recently reported impedance-based tattoo sensors and volatile samplers on both human participants and HSEs. The HSE exhibited a higher pH (6.5) and TDC (56) than human skin (pH 4.9–5.6, TDC 29–36), and the tattoo sensor revealed a lower impedance signal for HSEs, suggesting the model could maintain homeostasis, but in a different manner to human skin, which demonstrated a more highly resistive barrier. Characterisation of volatiles showed a variety of compound classes emanating from skin, with 16 and 27 compounds identified in HSEs and participants respectively. The continuing development of these tools offers potential for improved quality and relevance of data, and potential for detection of changes that are undetectable in traditional palpable and visual assessments, permitting early detection of irritant reactions. Full article

Current genetically-engineered mouse melanoma models are often based on Tyr::CreER^T2-controlled MAPK pathway activation by the BRAF^V600E mutation and PI3K pathway activation by loss of PTEN. The major drawback of these models is the occurrence of spontaneous tumors caused by leakiness of the Tyr::CreER^T2 system, hampering long-term experiments. To address this problem, we investigated several approaches to optimally provide local delivery of Cre recombinase, including injection of lentiviral particles, DNA tattoo administration and particle-mediated gene transfer, to induce melanomas in Pten^LoxP/LoxP;Braf^CA/+ mice lacking the Tyr::CreER^T2 allele. We found that dermal delivery of the Cre recombinase gene under the control of a non-specific CAG promoter induced the formation of melanomas, but also keratoacanthoma and squamous cell carcinomas. Delivery of Cre recombinase DNA under the control of melanocyte-specific promoters in Pten^LoxP/LoxP;Braf^CA/+ mice resulted in sole melanoma induction. The growth rate and histological features of the induced tumors were similar to 4-hydroxytamoxifen-induced tumors in Tyr::CreER^T2;Pten^LoxP/LoxP;Braf^CA/+ mice, while the onset of spontaneous tumors was prevented completely. These novel induction methods will allow long-term experiments in mouse models of skin malignancies. Full article