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In this paper we present a general theoretical framework to study interacting electrons under the influence of an external time-periodic driving, such as a homogeneous laser field. This is performed through a true many-body calculation and the use of Floquet theory. In particular, we consider a linear atomic chain using the Hubbard model to describe the short-ranged Coulomb interactions between electrons, plus Cluster Perturbation Theory to embed the many-body exact solution for a finite system into both an extended and an infinite lattice. Due to the presence of the external time-periodic perturbation, the electronic problem can be mapped into the study of photon-dressed quasiparticles thanks to Floquet theorem, keeping into account of all the virtual processes (absorption and emission of photons by electrons) with the laser field. This leads to an extension of the many-body static theories to out-of-equilibrium systems. This theoretical approach allowed us to show how the electronic properties of the system can be controlled and tuned varying the laser parameters. Above all, an inverse insulator-to-metal transition can be obtained for the one dimensional infinite lattice, and edge localized states appear as a finite size effect in an extended truncated chain.

Background: Survivin is detected in few adult normal cells and it is highly expressed in cancer. Nuclear survivin facilitates cell cycle entry, whereas the mitochondrial pool protects cells from apoptosis. Survivin is overexpressed in keratinocyte stem cells (KSCs) and protects them from apoptosis. Methods: As KSCs are at the origin of squamous cell carcinoma (SCC), we evaluated survivin expression in normal and cancerous skin in vivo by immunohistochemistry and western blotting. HaCaT cells overexpressing survivin and wound-healing assay are used. Analysis of variance and Student’s T -tests are used for statistical analysis. Results: Survivin is localised in both the cytoplasm and nucleus of normal adult and young keratinocytes. Nuclear survivin is detected in one every 10 of 11 basal keratinocytes. When present in suprabasal cells, nuclear survivin is coexpressed with K10 but not with K15 or p75-neurotrophin receptor (p75NTR), a transit amplifying cell marker. Nuclear, but not cytoplasmic, survivin expression markedly increases in actinic keratosis and in SCC in situ , as compared with normal epidermis, and it is highest in poorly differentiated SCC. In SCC tumours, nuclear survivin-positive cells are mainly K10/p75NTR-negative and K15-positive. In poorly differentiated tumours, survivin mostly localises in the deep infiltrating areas. When overexpressed in keratinocytes, survivin increases cell migration. Conclusion: High survivin expression and the subcellular localisation of survivin correlate with keratinocyte differentiation and are associated with undifferentiated and more invasive SCC phenotype.

Based on a solution of the Floquet Hamiltonian we have studied the time evolution of electronic states in graphene nanoribbons driven out of equilibrium by time-dependent electromagnetic fields in different regimes of intensity, polarization, and frequency. We show that the time-dependent band structure contains many unconventional features that are not captured by considering the Floquet eigenvalues alone. By analyzing the evolution in time of the state population we have identified regimes for the emergence of time-dependent edge states responsible for charge oscillations across the ribbon.

The Fas/Fas ligand system triggers the extrinsic apoptotic pathway and is involved in several inflammatory conditions, also at the skin level. The Fas/Fas ligand cell death pathway plays a major role in anoikis, a type of apoptosis characterized by cell detachment. As pemphigus is characterized by loss of cell to cell adhesion, we evaluated the role of anoikis and Fas ligand in this bullous disease. We report that, in suprabasal epidermis from perilesional pemphigus skin, most keratinocytes are apoptotic. Moreover, Fas ligand levels are markedly increased in sera from pemphigus patients, whereas they are undetectable in sera from patients undergoing steroid treatment. Sera from untreated patients but not from patients under steroids induce keratinocyte apoptosis. Pemphigus-sera-induced cell death is partially inhibited by pretreatment with anti-Fas ligand antibodies and by incubation with caspase-8 inhibitor Z-IETD-FMK. Finally, caspase-8 is activated in keratinocytes provided with sera from pemphigus patients, whereas cleavage is partially blocked by pretreatment of sera with anti-Fas ligand antibody. These results suggest that increased Fas ligand in pemphigus sera is responsible for keratinocyte apoptosis, which occurs through the activation of a caspase-8-driven extrinsic apoptotic pathway.

A new cream formulation containing hyaluronic acid 5%, complexed with a mix of a bacterial-wall-derived glycoprotein and peptide glycan complex (EDS), has been recently developed. We evaluated in a prospective, assessor-blinded, 6-week study the efficacy and tolerability of EDS in the treatment of facial seborrheic dermatitis (SD) and the effects on skin microbiota. Seventy-five subjects (mean age 46; 60 men) with moderate-severe SD of the face were enrolled. EDS cream was applied twice daily. The primary outcome was the evolution of the Investigator Global Assessment (IGA) score, evaluating erythema, scale/flaking, grade of seborrhea and itch. Superficial skin bacterial microbiome at baseline and after treatment was assessed, using the 16S rRNA gene methodology, in affected and non-affected face areas. Local tolerability was evaluated checking self-reported side effects at each visit. Baseline IGA scores (mean±SD) was 10±3. The use of EDS reduced IGA score significantly by 70% at week 3 and by 88% at week 6. An increase in the abundance of genera associated with a significant drop of genera presence was detected in affected areas. The ratio of relative abundance of genera Cutibacterium increased significantly after treatment in affected areas. The product was very well tolerated. Treatment with EDS applied twice daily for 6 consecutive weeks was associated with a reduction of the signs and symptoms of SD. Furthermore, after EDS cream treatment, a reequilibrating effect on facial skin microbiota was observed. The product was very well tolerated.

Introduction Lesion and field-targeted treatments of actinic keratosis (AK) are commonly indicated for grade I and II type lesions. Grade III lesions are in general more difficult to treat. A film-forming medical device containing piroxicam 0.8% and sunscreen (SPF 50+) (PS) has been shown to be effective in the treatment of grade I and II AK lesions. Topical and oral retinoids have been utilized in AK and non-melanoma skin cancers. Topical glycolic acid promotes keratolysis and stimulates collagen synthesis for repair and skin rejuvenation and could be useful in AK treatment strategies. A gel containing retinoid acid (0.02%) and glycolic acid (4%) (RC) is commercially available. The objective of the study was to evaluate the efficacy and local tolerability of a combined treatment approach with PS and RC in subjects with multiple grade II and III AK lesions. Methods Twenty-two subjects (16 males and 6 females; mean age 68 years) with more than five AK lesions were enrolled after obtaining their informed consent in a 3-month trial. PS cream was applied twice daily every day and RC gel was applied twice daily for 2 consecutive days every week. The primary endpoint was the evolution of the AK mean number from baseline to the end of the trial. Secondary endpoints were the thickness of the target lesion (expressed in mm 3 ) and the erythema score (hemoglobin content), evaluated using a standardized computer-based image acquisition analysis system (Anthera 3D). Results At baseline, the mean (SD) lesion number was 7.7 (3) for grade II and 1.4 (1) for grade III AK. At the end of the study, a significant ( P  = 0.001) reduction was observed for both grade II (− 81%; from 7.7 to 1.5) and grade III (− 22%) lesions. Six grade III lesions out of 31 (20%), presented at baseline, completely disappeared at month 3. For grade III lesions, a significant mean thickness reduction of 51% was observed at month 3. The erythema score (all lesions) was reduced by 70%. Four patients out of 22 (18%) were completely free of AK lesions at month 3. No severe side effects were reported. Conclusion In this exploratory trial, a combined treatment with a cream containing piroxicam and sunscreen and a retinoic/glycolic gel was associated with a substantial reduction of both grade II and III AK lesions with good local tolerability. Funding Cantabria Labs Difa Cooper.

We propose a method to study the time evolution of correlated electrons driven by an harmonic perturbation. Combining Floquet formalism to include the time-dependent field and Cluster Perturbation Theory to solve the many-body problem in the presence of short-range correlations, we treat the electron double dressing - by photons and by e-e interaction - on the same footing. We apply the method to an extended Hubbard chain at half occupation and we show that in the regime of small field frequency and for given values of field strength the zero-mode Floquet band is no more gapped and the system recovers a metallic state. Our results are indicative of an omnipresent mechanism for insulator-to-metal transition in 1D systems.

In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to eV-light mainly in a non-linear Raman-like process. The experimental non-equilibrium results on isotropic superconductors have been explained going beyond the BCS theory including the Higgs mode. Furthermore, in anisotropic d-wave superconductors strong interaction effects with other modes are expected. Here we calculate the Raman contribution of the Higgs mode from a new perspective, including many-body Higgs oscillations effects and their consequences in conventional, spontaneous Raman spectroscopy. Our results suggest a significant contribution to the intensity of the A1g symmetry Raman spectrum in d-wave superconductors. In order to test our theory, we predict the presence of measurable characteristic oscillations in THz quench-optical probe time-dependent reflectivity experiments.

Negative nonlinear electron-phonon coupling involving an infrared-active phonon mode can lead to an instability towards the formation of a polar lattice distortion with ferrielectric (FE) moments accompanied by an electronic charge-density wave (CDW). Analyzing a small model system in and out of thermal equilibrium, we investigate the FE-CDW and its melting dynamics following an ultrashort laser pulse that drives the ionic dipoles. We observe nonequilibrium coherent phonon amplitude mode oscillations that soften towards the transition to the normal phase. Our case study serves as a first step towards a microscopic understanding of quantum nonlinear phononics as a basis for nonequilibrium control in quantum materials.