PET-CT vs brain MRI for the detection of cerebral metastases of melanoma, a 5-year retrospective study.

BACKGROUND: Melanoma patients present a high risk of developing extra cutaneous metastases. PET-CT is one of the preferred examinations for the staging of oncological patients. It is not the method of choice to detect brain metastases, but this technique has shown significant improvement and allows the detection of some of them, although it is unclear how it performs compared to the MRI, the current gold standard for diagnosing brain metastases. OBJECTIVE: To compare the accuracy of PET-CT and cerebral MRI to detect brain metastases in melanoma patients. METHODS: We retrospectively included all patients diagnosed with melanoma stage IIC-IV (AJCC 8th Edition-2017) presented at the skin tumor board of the University Hospital of Bern between 01/2018 and 12/2022. All radiological reports extracted from the patient management system were analyzed to assess a discrepancy between the visibility of brain metastases on PET-CT and brain MRI. RESULTS: In this study including 393 patients, brain MRI demonstrated significantly higher performance than PET-CT in detecting brain metastases. Cerebral metastases were detected completely, partially or were not detected by PET-CT in respectively 2 patients (4%), 15 patients (32%) and 30 patients (64%) out of 47. CONCLUSION: Despite the increasing performance of PET-CT, this study highlights the crucial role of brain MRI, which remains the gold standard to detect cerebral metastases. Brain MRI should be performed on patients with high-risk melanoma from stage IIC to exclude brain metastases.

Confidence collapse in a multihousehold, self-reflexive DSGE model.

We investigate a multihousehold dynamic stochastic general equilibrium (DSGE) model in which past aggregate consumption impacts the confidence, and therefore consumption propensity, of individual households. We find that such a minimal setup is extremely rich and leads to a variety of realistic output dynamics: high output with no crises; high output with increased volatility and deep, short-lived recessions; and alternation of high- and low-output states where a relatively mild drop in economic conditions can lead to a temporary confidence collapse and steep decline in economic activity. The crisis probability depends exponentially on the parameters of the model, which means that markets cannot efficiently price the associated risk premium. We conclude by stressing that within our framework, narratives become an important monetary policy tool that can help steer the economy back on track.

Alignment and scattering of colliding active droplets.

Active droplets emit a chemical solute at their surface that modifies their local interfacial tension. They exploit the nonlinear coupling of the convective transport of solute to the resulting Marangoni flows in order to self-propel. Such swimming droplets are by nature anti-chemotactic and are repelled by their own chemical wake or their neighbours. The rebound dynamics resulting from pairwise droplet interactions was recently analysed in detail for purely head-on collisions using a specific bispherical approach. Here, we extend this analysis and propose a reduced model of a generic collision to characterise the alignment and scattering properties of oblique droplet collisions and their potential impact on collective droplet dynamics. A systematic alignment of the droplets' trajectories is observed for symmetric collisions, when the droplets interact directly, and arises from the finite-time rearrangement of the droplets' chemical wake during the collision. For more generic collisions, complex and diverse dynamical regimes are observed, whether the droplets interact directly or through their chemical wake, resulting in a significant scattering.

Laser-Assisted Hyaluronic Acid Delivery by Fractional Carbon Dioxide Laser in Facial Skin Remodeling: A Prospective Randomized Split-Face Study in France.

BACKGROUND AND OBJECTIVES: Combining the efficacy of ablative fractional carbon dioxide lasers (AFXL) to laser-assisted hyaluronic acid delivery (LAHAD) has not yet been studied. The objective of our study was to evaluate the safety and the efficacy of laser-assisted hyaluronic acid (HA) delivery with AFXL in facial skin remodeling. STUDY DESIGN/MATERIALS AND METHODS: We conducted a prospective, double-blinded, randomized split-face study on 20 patients from 30 to 70 years old, with a skin phototype from I to IV. Each patient received full-face treatment with AFXL, immediately followed by the application in droplets into the fractional ablative tunnels of 1 ml of HA gel on one hemiface and 1 ml of physiological saline on the other hemiface. To evaluate postlaser aftermath, the intensity of erythema, edema, and crusts was graded. To assess facial skin remodeling, we scored the improvement of skin texture, firmness, fine lines, and skin radiance from baseline. Patients were evaluated on the 3rd and 7th day, 1st and 3rd month using clinical evaluations, photographs, and patient questionnaires. RESULTS: We showed equivalence in postlaser aftermath between HA-treated and nontreated hemiface. Trend data analyses at the 3rd month suggested that immediate application of HA after AFXL resulted in a greater improvement in facial skin remodeling, especially for skin texture (mean score of 2.60 vs. 2.45) and skin firmness (mean score of 2.55 vs. 2.40). Skin radiance showed the best improvement, reaching almost a score of 5/10. CONCLUSIONS: LAHAD with AFXL is a safe treatment showing promising results in facial skin remodeling. These findings need to be confirmed by a larger study to evaluate the value of LAHAD in daily clinical practice. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Update on the anti-programmed cell death-1 receptor antibodies in advanced cutaneous squamous-cell carcinoma.

Regarding the rising incidence and the not negligible mortality, the treatment of cutaneous squamous-cell carcinoma (cSCC) has a high clinical relevance. Immune checkpoint inhibitors (ICI), especially anti-programmed cell death-1 receptor (anti-PD-1) antibodies such as pembrolizumab and cemiplimab have shown promising results in Phase 2 studies for patients with locally advanced and/or metastatic cSCC. We are presenting a review of the latest results in the treatment of cSCC with ICI. Patients with locally advanced or metastatic cSCC have been treated with cemiplimab 3 mg/kg every 2 weeks. For locally advanced cSCC, an objective response was observed in 44% of patients, 13% patients with a complete response, and 31% with a partial response. For metastatic patients, the overall response rate was 49.2%. The approved dose for cemiplimab in the United States and Europe is 350 mg every 3 weeks. These ICI seem to achieve higher response rates compared with epidermal growth factor receptor (EGFR) inhibitors, with a durable response superior to both chemotherapy and EGFR inhibitors. The side effect profile of anti-PD-1 antibodies appears to be favorable compared to chemotherapy. In this way, PD-1 inhibitors are expected to become the new gold-standard treatment for patients with locally advanced and metastatic cSCC.

By force of habit: Self-trapping in a dynamical utility landscape.

Historically, rational choice theory has focused on the utility maximization principle to describe how individuals make choices. In reality, there is a computational cost related to exploring the universe of available choices and it is often not clear whether we are truly maximizing an underlying utility function. In particular, memory effects and habit formation may dominate over utility maximization. We propose a stylized model with a history-dependent utility function, where the utility associated to each choice is increased when that choice has been made in the past, with a certain decaying memory kernel. We show that self-reinforcing effects can cause the agent to get stuck with a choice by sheer force of habit. We discuss the special nature of the transition between free exploration of the space of choice and self-trapping. We find, in particular, that the trapping time distribution is precisely a Zipf law at the transition, and that the self-trapped phase exhibits super-aging behavior.

Development and accuracy of an artificial intelligence algorithm for acne grading from smartphone photographs.

We developed an artificial intelligence algorithm (AIA) for smartphones to determine the severity of facial acne using the GEA scale and to identify different types of acne lesion (comedonal, inflammatory) and postinflammatory hyperpigmentation (PIHP) or residual hyperpigmentation. Overall, 5972 images (face, right and left profiles) obtained with smartphones (IOS and/or Android) from 1072 acne patients were collected. Three trained dermatologists assessed the acne severity for each patient. One acne severity grade per patient (grade given by the majority of the three dermatologists from the two sets of three images) was used to train the algorithm. Acne lesion identification was performed from a subgroup of 348 images using a tagging tool; tagged images served to train the algorithm. The algorithm evolved and was adjusted for sensibility, specificity and correlation using new images. The correlation between the GEA grade and the quantification and qualification of acne lesions both by the AIA and the experts for each image were evaluated for all AIA versions. At final version 6, the GEA grading provided by AIA reached 68% and was similar to that provided by the dermatologists. Between version 4 and version 6, AIA improved precision results multiplied by 1.5 for inflammatory lesions, 2.5 for non-inflammatory lesions and by 2 for PIHP; recall was improved by 2.6, 1.6 and 2.7. The weighted average of precision and recall or F1 score was 84% for inflammatory lesions, 61% for non-inflammatory lesions and 72% for PIHP.

Crossover from Linear to Square-Root Market Impact.

Using a large database of 8 million institutional trades executed in the U.S. equity market, we establish a clear crossover between a linear market impact regime and a square-root regime as a function of the volume of the order. Our empirical results are remarkably well explained by a recently proposed dynamical theory of liquidity that makes specific predictions about the scaling function describing this crossover. Allowing at least two characteristic timescales for the liquidity ("fast" and "slow") enables one to reach quantitative agreement with the data.

Waltzing route toward double-helix formation in cholesteric shells.

Liquid crystals, when confined to a spherical shell, offer fascinating possibilities for producing artificial mesoscopic atoms, which could then self-assemble into materials structured at a nanoscale, such as photonic crystals or metamaterials. The spherical curvature of the shell imposes topological constraints in the molecular ordering of the liquid crystal, resulting in the formation of defects. Controlling the number of defects, that is, the shell valency, and their positions, is a key success factor for the realization of those materials. Liquid crystals with helical cholesteric order offer a promising, yet unexplored way of controlling the shell defect configuration. In this paper, we study cholesteric shells with monovalent and bivalent defect configurations. By bringing together experiments and numerical simulations, we show that the defects appearing in these two configurations have a complex inner structure, as recently reported for simulated droplets. Bivalent shells possess two highly structured defects, which are composed of a number of smaller defect rings that pile up through the shell. Monovalent shells have a single radial defect, which is composed of two nonsingular defect lines that wind around each other in a double-helix structure. The stability of the bivalent configuration against the monovalent one is controlled by c = h/p, where h is the shell thickness and p the cholesteric helical pitch. By playing with the shell geometry, we can trigger the transition between the two configurations. This transition involves a fascinating waltz dynamics, where the two defects come closer while turning around each other.

Slip-mediated dewetting of polymer microdroplets.

Classical hydrodynamic models predict that infinite work is required to move a three-phase contact line, defined here as the line where a liquid/vapor interface intersects a solid surface. Assuming a slip boundary condition, in which the liquid slides against the solid, such an unphysical prediction is avoided. In this article, we present the results of experiments in which a contact line moves and where slip is a dominating and controllable factor. Spherical cap-shaped polystyrene microdroplets, with nonequilibrium contact angle, are placed on solid self-assembled monolayer coatings from which they dewet. The relaxation is monitored using in situ atomic force microscopy. We find that slip has a strong influence on the droplet evolutions, both on the transient nonspherical shapes and contact line dynamics. The observations are in agreement with scaling analysis and boundary element numerical integration of the governing Stokes equations, including a Navier slip boundary condition.

Dipeptidyl peptidase IV inhibitors, a risk factor for bullous pemphigoid: Retrospective multicenter case-control study from France and Switzerland.

BACKGROUND: Case reports have suggested an association between dipeptidyl peptidase-4 inhibitors (DPP4is) and development of bullous pemphigoid (BP). OBJECTIVE: To evaluate the association between DPP4i treatment and development of BP. METHODS: We conducted a retrospective 1:2 case-control study, comparing case patients with diabetes and BP with age- and sex-matched control patients with diabetes issued from Swiss (Bern) and French (Marseille) dermatologic departments from January 1, 2014, to July 31, 2016. RESULTS: We collected 61 case patients with diabetes and BP and 122 controls. DPP4is were associated with an increased risk for development of BP (adjusted odds ratio, 2.64; 95% confidence interval, 1.19-5.85; P = .02), with vildagliptin showing the highest adjusted odds ratio (3.57 [95% confidence interval, 1.07-11.84; P = .04]). Stratified analysis showed a stronger association in males and patients age 80 years or older. DPP4i withdrawal and the initiation of first-line treatments led to clinical remission in 95% of cases. LIMITATIONS: This was a retrospective study in tertiary referral hospitals. We focused the analysis on DPP4i intake, without analyzing the potential isolated effect of metformin. CONCLUSIONS: DPP4is, especially vildagliptin, are associated with an increased risk for development of BP. Their use needs to be carefully evaluated, particularly in high-risk patients, such as males and those age 80 years or older.

Paradoxical pustular psoriasis induced by ustekinumab in a patient with Crohn's disease-associated spondyloarthropathy.

Palmoplantar pustular psoriasis (PPP) is a clinical form of psoriasis, for which tumor necrosis factor alpha inhibitors (TNFi) or interleukins 12/23 inhibitor (ustekinumab) can be a therapeutic option. Paradoxical psoriatic reactions induced by TNFi are now well known. We present the exceptional case of a paradoxical PPP appeared under ustekinumab in a patient with Crohn's disease-associated spondyloarthropathy. A 58-year-old woman presented with recent peripheral inflammatory arthralgias appeared in the context of a Crohn's disease diagnosed in 2008. Three weeks after the first injection of ustekinumab 390 mg for a refractory Crohn's disease, a slight pruritic erythematous and pustular dermatosis appeared on the right hand palm. The clinical aspect was strongly in favor of a PPP. Ustekinumab was discontinued and replaced by golimumab, leading to a complete healing of PPP after 15 days of discontinuation. Causality assessment calculated using the French method was plausible for ustekinumab in the induction of PPP. It was based on a compatible chronology according to time to onset associated with complete recovery 2 weeks after cessation of treatment, and on the negative assessment of an alternative etiology (nor bacterial or viral infection, nor other treatment taken by the patient, nor previous history of psoriasis). The worsening of underlying psoriasis under ustekinumab through the appearance of generalized or palmoplantar pustules has already been reported in five cases. We describe to our knowledge the first case of paradoxical PPP under ustekinumab in a patient with no known underlying psoriasis.

Primary cutaneous nocardiosis caused by Nocardia takedensis with pulmonary dissemination in an immunosuppressed patient.

We present a remarkable case of primary cutaneous nocardiosis with pulmonary dissemination due to Nocardia takedensis in a 76-year-old man suffering from marginal zone lymphoma and hypogammaglobulinaemia. We also discuss an alternative treatment to trimethoprim-sulfamethoxazole, which could be contraindicated due to haematological and cutaneous toxicities. This case report is of interest due to the emergence of cutaneous nocardiosis in dermatology.

Capillary Leveling of Freestanding Liquid Nanofilms.

We report on the capillary-driven leveling of a topographical perturbation at the surface of a freestanding liquid nanofilm. The width of a stepped surface profile is found to evolve as the square root of time. The hydrodynamic model is in excellent agreement with the experimental data. In addition to exhibiting an analogy with diffusive processes, this novel system serves as a precise nanoprobe for the rheology of liquids at interfaces in a configuration that avoids substrate effects.

Topological defects in cholesteric liquid crystal shells.

We investigate experimentally and numerically the defect configurations emerging when a cholesteric liquid crystal is confined to a spherical shell. We uncover a rich scenario of defect configurations, some of them non-existent in nematic shells, where new types of defects are stabilized by the helical ordering of the liquid crystal. In contrast to nematic shells, here defects are not simple singular points or lines, but have a large structured core. Specifically, we observe five different types of cholesteric shells. We study the statistical distribution of the different types of shells as a function of the two relevant geometrical dimensionless parameters of the system. By playing with these parameters, we are able to induce transitions between different types of shells. These transitions involve interesting topological transformations in which the defects recombine to form new structures. Surprisingly, the defects do not approach each other by taking the shorter distance route (geodesic), but by following intricate paths.

Shape and Effective Spring Constant of Liquid Interfaces Probed at the Nanometer Scale: Finite Size Effects.

We investigate the shape and mechanical properties of liquid interfaces down to nanometer scale by atomic force microscopy (AFM) and scanning electron microscopy (SEM) combined with in situ micromanipulation techniques. In both cases, the interface is probed with a cylindrical nanofiber with radius R of the order of 25-100 nm. The effective spring constant of the nanomeniscus oscillated around its equilibrium position is determined by static and frequency-modulation (FM) AFM modes. In the case of an unbounded meniscus, we find that the effective spring constant k is proportional to the surface tension γ of the liquid through k = (0.51 ± 0.06)γ, regardless of the excitation frequency from quasi-static up to 450 kHz. A model based on the equilibrium shape of the meniscus reproduces well the experimental data. Electron microscopy allowed to visualize the meniscus profile around the fiber with a lateral resolution of the order of 10 nm and confirmed its catenary shape. The influence of a lateral confinement of the interface is also investigated. We showed that the lateral extension L of the meniscus influences the effective spring constant following a logarithmic evolution k ∼ 2πγ/ln(L/R) deduced from the model. This comprehensive study of liquid interface properties over more than 4 orders of magnitude in meniscus size shows that advanced FM-AFM and SEM techniques are promising tools for the investigation of mechanical properties of liquids down to nanometer scale.

Universal contact-line dynamics at the nanoscale.

The relaxation dynamics of the contact angle between a viscous liquid and a smooth substrate is studied at the nanoscale. Through atomic force microscopy measurements of polystyrene nanostripes we simultaneously monitor both the temporal evolution of the liquid-air interface and the position of the contact line. The initial configuration exhibits high curvature gradients and a non-equilibrium contact angle that drive liquid flow. Both these conditions are relaxed to achieve the final state, leading to three successive regimes in time: (i) stationary contact line levelling; (ii) receding contact line dewetting; (iii) collapse of the two fronts. For the first regime, we reveal the existence of a self-similar evolution of the liquid interface, which is in excellent agreement with numerical calculations from a lubrication model. For different liquid viscosities and film thicknesses we provide evidence for a transition to dewetting featuring a universal critical contact angle and dimensionless time.

Capillary levelling of a cylindrical hole in a viscous film.

The capillary levelling of cylindrical holes in viscous polystyrene films was studied using atomic force microscopy as well as quantitative analytical scaling arguments based on thin film theory and self-similarity. The relaxation of the holes was shown to consist of two different time regimes: an early regime where opposing sides of the hole do not interact, and a late regime where the hole is filling up. For the latter, the self-similar asymptotic profile was derived analytically and shown to be in excellent agreement with experimental data. Finally, a binary system of two holes in close proximity was investigated where the individual holes fill up at early times and coalesce at longer times.