Search

In situ investigations of cracks propagating at up to 2.5 km s-1 along an (001) plane of a silicon single crystal are reported, using X-ray diffraction megahertz imaging with intense and time-structured synchrotron radiation. The studied system is based on the Smart Cut process, where a buried layer in a material (typically Si) is weakened by microcracks and then used to drive a macroscopic crack (10-1 m) in a plane parallel to the surface with minimal deviation (10-9 m). A direct confirmation that the shape of the crack front is not affected by the distribution of the microcracks is provided. Instantaneous crack velocities over the centimetre-wide field of view were measured and showed an effect of local heating by the X-ray beam. The post-crack movements of the separated wafer parts could also be observed and explained using pneumatics and elasticity. A comprehensive view of controlled fracture propagation in a crystalline material is provided, paving the way for the in situ measurement of ultra-fast strain field propagation. [ABSTRACT FROM AUTHOR]

Introduction: Software to predict the impact of aging on physical appearance is increasingly popular. But it does not consider the complex interplay of factors that contribute to skin aging. Objectives: To predict the +15‐year progression of clinical signs of skin aging by developing Causal Bayesian Belief Networks (CBBNs) using expert knowledge from dermatologists. Material and methods: Structures and conditional probability distributions were elicited worldwide from dermatologists with experience of at least 15 years in aesthetics. CBBN models were built for all phototypes and for ages ranging from 18 to 65 years, focusing on wrinkles, pigmentary heterogeneity and facial ptosis. Models were also evaluated by a group of independent dermatologists ensuring the quality of prediction of the cumulative effects of extrinsic and intrinsic skin aging factors, especially the distribution of scores for clinical signs 15 years after the initial assessment. Results: For easiness, only models on African skins are presented in this paper. The forehead wrinkle evolution model has been detailed. Specific atlas and extrinsic factors of facial aging were used for this skin type. But the prediction method has been validated for all phototypes, and for all clinical signs of facial aging. Conclusion: This method proposes a skin aging model that predicts the aging process for each clinical sign, considering endogenous and exogenous factors. It simulates aging curves according to lifestyle. It can be used as a preventive tool and could be coupled with a generative AI algorithm to visualize aging and, potentially, other skin conditions, using appropriate images. [ABSTRACT FROM AUTHOR]

Background: In addition to general measures, pharmacological treatment is the basis of the management of scabies. No recent data in real‐life are available on the efficacy and safety of 10% benzyl benzoate emulsion for skin application administered as monotherapy. Method: This prospective, multicenter, French observational study comprised a registry and a prospective cohort with a follow‐up at 28 days and a telephone call at week 12. To participate in the registry, patients had to be over 1 month old, ambulatory, presenting common, nonhyperkeratotic, untreated scabies. To be included in the cohort, patients had to be included in the registry and treated with two applications of 10% benzyl benzoate emulsion 8 days apart. The primary endpoint was cure at day 28. Results: Of the 186 patients included in the registry, 116 were included in the cohort. Fourteen patients were included in the cohort without being included in the registry, which led to a total of 130 patients in the cohort. At day 28, 119/130 (91.5%; 95% CI 85.4–95.6%) were clinically cured. The cure was confirmed by dermoscopy in 44/47 patients (93%). Among the 130 patients, the cure rate was 82% at week 12. Of the 119 patients cured at day 28, the rate of cure at week 12 was 89.9%. Conclusion: In real life, two applications of 10% benzyl benzoate emulsion 8 days apart provides high cure rates in patients with common scabies. [ABSTRACT FROM AUTHOR]

The article titled "Back Cover" is based on the original article "Predicting the evolution of clinical skin aging in a multi-ethnic population: Developing causal Bayesian networks using dermatological expertise" by Hussein Jouni et al. The study focuses on predicting the progression of skin aging in a diverse population using Bayesian networks. The authors include a wide range of experts in the field of dermatology and explore the impact of various factors on skin aging. This research provides valuable insights into understanding and addressing skin aging in different ethnic groups. [Extracted from the article]

Background: Some keloids show cystic cavities that give rise to acute inflammatory flares and oozing. These suppurative keloids (SK) have rarely been systematically studied. We conducted a retrospective cohort study to evaluate SK frequency and its risk factors. We also reviewed microbiological analyses as well as the histological features of removed SKs. Methods: Between July 1, 2015, and September 30, 2016, all adult patients attending a specialized keloid clinic were asked to participate. Clinical information and microbiological results were extracted from each patient's file. Histological features were observed and interpreted. Results: In this study, we observed an SK rate of 26% for a mean keloid history of 17.2 years. Male gender, African ancestry, and a family history of keloids were significantly associated with suppuration. Microbiological examination revealed commensal skin flora 7/9 (77.8%), Staphylococcus aureus 1/9 (11.1%), and Enterococcus faecalis 1/9 (11.1%). Conclusion: Suppuration is a common complication of keloids occurring in patients with severe keloid disease and may arise from pilosebaceous occlusion and aseptic inflammation. [ABSTRACT FROM AUTHOR]

Folliculitis decalvans (FD) is a chronic inflammatory disease of unknown aetiology. Although Staphylococcus aureus, frequently found on lesional skin, is thought to play a causal role, the importance of its involvement remains controversial. To examine the role of S aureus, we compared superficial and subepidermal microbiota in 20 FD patients who had S aureus on lesional skin and in 20 healthy controls using culture techniques and genomic identification, before and after an anti‐staphylococcal treatment; we also screened for S aureus virulence factors. When present on lesional skin, S aureus colonized non‐lesional and subepidermal skin in 80% of cases. These data imply a break in the epidermal barrier integrity and that an abnormal non‐lesional skin microbiota persists in FD. S aureus had no superantigenic toxin in 31% of cases and no toxin specificity. Clinical improvement obtained in most cases upon treatment was associated with the disappearance of S aureus in all studied areas, with an incomplete restoration of normal microbiota and a significant increase in negative bacterial samples. This persistent unbalanced, subepidermal microbiota may act as a reservoir of abnormal flora and explain the chronicity of FD, suggesting new avenues of research to restore normal microbiota. [ABSTRACT FROM AUTHOR]

Background Livedoid vasculopathy ( LV) is a thrombotic vasculopathy of the skin of unknown origin. No treatment has been validated in this indication, but case reports suggest the successful use of intravenous immunoglobulins (IVIG) in LV. Methods Outcomes in five patients treated with IVIG for treatment-resistant ulcerated LV were retrospectively analyzed. Results Treatment with IVIG induced complete remission (based on clinical evaluation and a pain-related visual analog scale) in four patients but was ineffective in one patient. Three patients relapsed; the median time to relapse was 10.7 months. Re-treatment with IVIG in these three patients was successful. Conclusions These cases confirm previous reports that IVIG seems to be a rapid, effective, and safe treatment for patients with idiopathic refractory ulcerated LV. However, a placebo-controlled study is mandatory to confirm these results. [ABSTRACT FROM AUTHOR]