Explore the vast range of titles available.

Delinquent behaviour is predominantly an expression of adolescent developmental phases, but at the same time a possible entry into criminal careers. Where socio-educational measures and admonitions no longer help, society reacts with youth detention and imprisonment as a last resort, in doing so it brings the young people into an environment of violence and power. The concept of the socio-educational pilgrimage as an alternative measure to imprisonment takes the young people out of this context and offers space for reflection and self-efficacy. In this article, different concepts of Learning Walks for young offenders are discussed and theoretically analysed.

The application of multiphoton microscopy in the field of biomedical research and advanced diagnostics promises unique insights into the pathophysiology of inflammatory skin diseases. In the present study, we combined multiphoton-based intravital tomography (MPT) and fluorescence lifetime imaging (MPT-FLIM) within the scope of a clinical trial of atopic dermatitis with the aim of providing personalised data on the aetiopathology of inflammation in a non-invasive manner at patients’ bedsides. These ‘optical biopsies’ generated via MPT were morphologically analysed and aligned with classical skin histology. Because of its subcellular resolution, MPT provided evidence of a redistribution of mitochondria in keratinocytes, indicating an altered cellular metabolism. Two independent morphometric algorithms reliably showed an even distribution in healthy skin and a perinuclear accumulation in inflamed skin. Moreover, using MPT-FLIM, detection of the onset and progression of inflammatory processes could be achieved. In conclusion, the change in the distribution of mitochondria upon inflammation and the verification of an altered cellular metabolism facilitate a better understanding of inflammatory skin diseases and may permit early diagnosis and therapy.

The diagnostic possibilities of multiphoton tomography (MPT) in dermatology have already been demonstrated. Nevertheless, the analysis of MPT data is still time-consuming and operator dependent. We propose a fully automatic approach based on convolutional neural networks (CNNs) to fully realize the potential of MPT. In total, 3,663 MPT images combining both morphological and metabolic information were acquired from atopic dermatitis (AD) patients and healthy volunteers. These were used to train and tune CNNs to detect the presence of living cells, and if so, to diagnose AD, independently of imaged layer or position. The proposed algorithm correctly diagnosed AD in 97.0 ± 0.2% of all images presenting living cells. The diagnosis was obtained with a sensitivity of 0.966 ± 0.003, specificity of 0.977 ± 0.003 and F-score of 0.964 ± 0.002. Relevance propagation by deep Taylor decomposition was used to enhance the algorithm’s interpretability. Obtained heatmaps show what aspects of the images are important for a given classification. We showed that MPT imaging can be combined with artificial intelligence to successfully diagnose AD. The proposed approach serves as a framework for the automatic diagnosis of skin disorders using MPT.

Background: Multiphoton tomography (MPT) is a femtosecond laser imaging technique that enables high-resolution virtual biopsies of human skin. It provides a non-invasive method for analyzing cellular metabolism, structural changes, and responses to cosmetic products, providing insights into cell–cosmetic interactions. This review explores the principles, historical development, and key applications of MPT in cosmetic research. Methods: The latest MPT device combines five modalities: (i) two-photon fluorescence: visualizes cells, elastin, and cosmetic ingredients; (ii) second harmonic generation (SHG): maps the collagen network; (iii) fluorescence lifetime imaging (FLIM): differentiates eumelanin from pheomelanin and evaluates the impact of cosmetics on cellular metabolic activity; (iv) reflectance confocal microscopy (RCM): images cell membranes and cosmetic particles; and (v) white LED imaging for dermoscopy. Results: MPT enables in-depth examination of extracellular matrix changes, cellular metabolism, and melanin production. It identifies skin responses to cosmetic products and tracks the intratissue distribution of sunscreen nanoparticles, nano- and microplastics, and other cosmetic components. Quantitative measurements, such as the elastin-to-collagen ratio, provide insights into anti-aging effects. Conclusions: MPT is a powerful in vivo imaging tool for the cosmetic industry. Its superior resolution and metabolic information facilitate the evaluation of product efficacy and support the development of personalized skincare solutions.

JBO guest editors introduce the Special Section Celebrating Thirty Years of Multiphoton Microscopy in the Biomedical Sciences..JBO guest editors introduce the Special Section Celebrating Thirty Years of Multiphoton Microscopy in the Biomedical Sciences..

The incidence of malignant melanoma has shown a dramatic increase over the past three decades. Patient outcome and curability depend on early diagnosis. In vivo multiphoton laser tomography represents a recently developed diagnostic tool that allows non-invasive tissue imaging. We aim to demonstrate the application of multiphoton laser tomography for the in vivo differentiation and diagnosis of melanoma. Laser radiation in the near infrared spectrum was used to image endogenous fluorophores by multiphoton excitation. Eighty-three melanocytic skin lesions have been investigated. The results showed distinct morphological differences in melanoma compared with melanocytic nevi. In particular, six characteristic features of malignant melanoma were specified and statistically evaluated. Sensitivity values up to 95% (range: 71–95%) and specificity values up to 97% (range: 69–97%) were achieved for diagnostic classification. Logistic regression analysis was performed to identify the most significant diagnostic criteria. We found that architectural disarray of the epidermis, poorly defined keratinocyte cell borders as well as the presence of pleomorphic or dendritic cells were of prime importance. By means of this procedure accuracy values up to 97% were reached. These findings underline the potential applicability of multiphoton laser tomography in melanoma diagnosis of melanocytic skin lesions.

The challenge for successful delivery of foreign DNA into cells in vitro, a key technique in cell and molecular biology with important biomedical implications, is to improve transfection efficiency while leaving the cell's architecture intact. Here we show that a variety of mammalian cells can be directly transfected with DNA without perturbing their structure by first creating a tiny, localized perforation in the membrane using ultrashort (femtosecond), high-intensity, near-infrared laser pulses. Not only does this superior optical technique give high transfection efficiency and cell survival, but it also allows simultaneous evaluation of the integration and expression of the introduced gene.

The clinical outcome of corneal collagen crosslinking (CXL) is typically evaluated several weeks after treatment. An earlier assessment of its outcome could lead to an optimization of the treatment, including an immediate re-intervention in case of failure, thereby, avoiding additional discomfort and pain to the patient. In this study, we propose two-photon imaging (TPI) as an earlier evaluation method. CXL was performed in human corneas by application of riboflavin followed by UVA irradiation. Autofluorescence (AF) intensity and lifetime images were acquired using a commercial clinically certified multiphoton tomograph prior to CXL and after 2 h , 24 h , 72 h , and 144 h storage in culture medium. The first monitoring point was determined as the minimum time required for riboflavin clearance from the cornea. As control, untreated samples and samples treated only with riboflavin (without UVA irradiation) were monitored at the same time points. Significant increases in the stroma AF intensity and lifetime were observed as soon as 2 h after treatment. A depth-dependent TPI analysis showed higher AF lifetimes anteriorly corresponding to areas were CXL was most effective. No alterations were observed in the control groups. Using TPI, the outcome of CXL can be assessed non-invasively and label-free much sooner than with conventional clinical devices.

Optoporation, the permeabilization of a cell membrane by laser pulses, has emerged as a powerful non-invasive and highly efficient technique to induce transfection of cells. However, the usual tedious manual targeting of individual cells significantly limits the addressable cell number. To overcome this limitation, we present an experimental setup with custom-made software control, for computer-automated cell optoporation. The software evaluates the image contrast of cell contours, automatically designates cell locations for laser illumination, centres those locations in the laser focus and executes the illumination. By software-controlled meandering of the sample stage, in principle all cells in a typical cell culture dish can be targeted without further user interaction. The automation allows for a significant increase in the number of treatable cells compared to a manual approach. For a laser illumination duration of 100 ms, 7-8 positions on different cells can be targeted every second inside the area of the microscope field of view. The experimental capabilities of the setup are illustrated in experiments with Chinese hamster ovary cells. Furthermore, the influence of laser power is discussed, with mention on post-treatment cell survival and optoporation-efficiency rates.

Multiphoton laser tomography (MPT) combined with fluorescence lifetime imaging (FLIM) is a non-invasive imaging technique, based on the study of fluorescence decay times of naturally occurring fluorescent molecules, enabling a non-invasive investigation of the skin with subcellular resolution. The aim of this retrospective observational ex vivo study, was to characterize melanoma both from a morphologic and a quantitative point of view, attaining an improvement in the diagnostic accuracy with respect to dermoscopy. In the training phase, thirty parameters, comprising both cytological descriptors and architectural aspects, were identified. The training set included 6 melanomas with a mean Breslow thickness±S.D. of 0.89±0.48 mm. In the test phase, these parameters were blindly evaluated on a test data set consisting of 25 melanomas, 50 nevi and 50 basal cell carcinomas. Melanomas in the test phase comprised 8 in situ lesions and had a mean thickness±S.D. of 0.77±1.2 mm. Moreover, quantitative FLIM data were calculated for special areas of interest. Melanoma was characterized by the presence of atypical short lifetime cells and architectural disorder, in contrast to nevi presenting typical cells and a regular histoarchitecture. Sensitivity and specificity values for melanoma diagnosis were 100% and 98%, respectively, whereas dermoscopy achieved the same sensitivity, but a lower specificity (82%). Mean fluorescence lifetime values of melanocytic cells did not vary between melanomas and nevi, but significantly differed from those referring to basal cell carcinoma enabling a differential diagnosis based on quantitative data. Data from prospective preoperative trials are needed to confirm if MPT/FLIM could increase diagnostic specificity and thus reduce unnecessary surgical excisions.