Design rules for controlling active topological defects.

Topological defects play a central role in the physics of many materials, including magnets, superconductors, and liquid crystals. In active fluids, defects become autonomous particles that spontaneously propel from internal active stresses and drive chaotic flows stirring the fluid. The intimate connection between defect textures and active flow suggests that properties of active materials can be engineered by controlling defects, but design principles for their spatiotemporal control remain elusive. Here, we propose a symmetry-based additive strategy for using elementary activity patterns, as active topological tweezers, to create, move, and braid such defects. By combining theory and simulations, we demonstrate how, at the collective level, spatial activity gradients act like electric fields which, when strong enough, induce an inverted topological polarization of defects, akin to a negative susceptibility dielectric. We harness this feature in a dynamic setting to collectively pattern and transport interacting active defects. Our work establishes an additive framework to sculpt flows and manipulate active defects in both space and time, paving the way to design programmable active and living materials for transport, memory, and logic.

Family matters inside the order Agaricales: systematic reorganization and classification of incertae sedis clitocyboid, pleurotoid and tricholomatoid taxa based on an updated 6-gene phylogeny.

The phylogenetic position of several clitocyboid/pleurotoid/tricholomatoid genera previously considered incertae sedis is here resolved using an updated 6-gene dataset of Agaricales including newly sequenced lineages and more complete data from those already analyzed before. Results allowed to infer new phylogenetic relationships, and propose taxonomic novelties to accommodate them, including up to ten new families and a new suborder. Giacomia (for which a new species from China is here described) forms a monophyletic clade with Melanoleuca (Melanoleucaceae) nested inside suborder Pluteineae, together with the families Pluteaceae, Amanitaceae (including Leucocortinarius), Limnoperdaceae and Volvariellaceae. The recently described family Asproinocybaceae is shown to be a later synonym of Lyophyllaceae (which includes also Omphaliaster and Trichocybe) within suborder Tricholomatineae. The families Biannulariaceae, Callistosporiaceae, Clitocybaceae, Fayodiaceae, Macrocystidiaceae (which includes Pseudoclitopilus), Entolomataceae, Pseudoclitocybaceae (which includes Aspropaxillus), Omphalinaceae (Infundibulicybe and Omphalina) and the new families Paralepistaceae and Pseudoomphalinaceae belong also to Tricholomatineae. The delimitation of the suborder Pleurotineae (= Schizophyllineae) is discussed and revised, accepting five distinct families within it, viz. Pleurotaceae, Cyphellopsidaceae, Fistulinaceae, Resupinataceae and Schizophyllaceae. The recently proposed suborder Phyllotopsidineae (= Sarcomyxineae) is found to encompass the families Aphroditeolaceae, Pterulaceae, Phyllotopsidaceae, Radulomycetaceae, Sarcomyxaceae (which includes Tectella), and Stephanosporaceae, all of them unrelated to Pleurotaceae (suborder Pleurotineae) or Typhulaceae (suborder Typhulineae). The new family Xeromphalinaceae, encompassing the genera Xeromphalina and Heimiomyces, is proposed within Marasmiineae. The suborder Hygrophorineae is here reorganized into the families Hygrophoraceae, Cantharellulaceae, Cuphophyllaceae, Hygrocybaceae and Lichenomphaliaceae, to homogenize the taxonomic rank of the main clades inside all suborders of Agaricales. Finally, the genus Hygrophorocybe is shown to represent a distinct clade inside Cuphophyllaceae, and the new combination H. carolinensis is proposed. Taxonomic novelties: New suborder: Typhulineae Vizzini, Consiglio & P. Alvarado. New families: Aphroditeolaceae Vizzini, Consiglio & P. Alvarado, Melanoleucaceae Locq. ex Vizzini, Consiglio & P. Alvarado, Paralepistaceae Vizzini, Consiglio & P. Alvarado, Pseudoomphalinaceae Vizzini, Consiglio & P. Alvarado, Volvariellaceae Vizzini, Consiglio & P. Alvarado, Xeromphalinaceae Vizzini, Consiglio & P. Alvarado. New species: Giacomia sinensis J.Z. Xu. Stat. nov.: Cantharellulaceae (Lodge, Redhead, Norvell & Desjardin) Vizzini, Consiglio & P. Alvarado, Cuphophyllaceae (Z.M. He & Zhu L. Yang) Vizzini, Consiglio & P. Alvarado, Hygrocybaceae (Padamsee & Lodge) Vizzini, Consiglio & P. Alvarado, Lichenomphaliaceae (Lücking & Redhead) Vizzini, Consiglio & P. Alvarado. New combination: Hygrophorocybe carolinensis (H.E. Bigelow & Hesler) Vizzini, Consiglio & P. Alvarado. New synonyms: Sarcomyxineae Zhu L. Yang & G.S. Wang, Schizophyllineae Aime, Dentinger & Gaya, Asproinocybaceae T. Bau & G.F. Mou. Incertae sedis taxa placed at family level: Aphroditeola Redhead & Manfr. Binder, Giacomia Vizzini & Contu, Hygrophorocybe Vizzini & Contu, Leucocortinarius (J.E. Lange) Singer, Omphaliaster Lamoure, Pseudoclitopilus Vizzini & Contu, Resupinatus Nees ex Gray, Tectella Earle, Trichocybe Vizzini. New delimitations of taxa: Hygrophorineae Aime, Dentinger & Gaya, Phyllotopsidineae Zhu L. Yang & G.S. Wang, Pleurotineae Aime, Dentinger & Gaya, Pluteineae Aime, Dentinger & Gaya, Tricholomatineae Aime, Dentinger & Gaya. Resurrected taxa: Fayodiaceae Jülich, Resupinataceae Jülich. Citation: Vizzini A, Alvarado P, Consiglio G, Marchetti M, Xu J (2024). Family matters inside the order Agaricales: systematic reorganization and classification of incertae sedis clitocyboid, pleurotoid and tricholomatoid taxa based on an updated 6-gene phylogeny. Studies in Mycology 107: 67-148. doi: 10.3114/sim.2024.107.02.

Constitutive model for the rheology of biological tissue.

The rheology of biological tissue is key to processes such as embryo development, wound healing, and cancer metastasis. Vertex models of confluent tissue monolayers have uncovered a spontaneous liquid-solid transition tuned by cell shape; and a shear-induced solidification transition of an initially liquidlike tissue. Alongside this jamming/unjamming behavior, biological tissue also displays an inherent viscoelasticity, with a slow time and rate-dependent mechanics. With this motivation, we combine simulations and continuum theory to examine the rheology of the vertex model in nonlinear shear across a full range of shear rates from quastistatic to fast, elucidating its nonlinear stress-strain curves after the inception of shear of finite rate, and its steady state flow curves of stress as a function of strain rate. We formulate a rheological constitutive model that couples cell shape to flow and captures both the tissue solid-liquid transition and its rich linear and nonlinear rheology.

Motility induced phase separation of deformable cells.

Using a multi-phase field model, we examine how particle deformability, which is a proxy for cell stiffness, affects motility induced phase separation (MIPS). We show that purely repulsive deformable, i.e., squishy, cells phase separate more effectively than their rigid counterparts. This can be understood as due to the fact that deformability increases the effective duration of collisions. In addition, the dense regions become increasingly disordered as deformability increases. Our results contextualize the applicability of MIPS to biological systems and have implications for how cells in biological systems may self-organize.

Finite elasticity of the vertex model and its role in rigidity of curved cellular tissues.

Using a mean field approach and simulations, we study the non-linear mechanical response of the vertex model (VM) of biological tissue to compression and dilation. The VM is known to exhibit a transition between solid and fluid-like, or floppy, states driven by geometric incompatibility. Target perimeter and area set a target shape which may not be geometrically achievable, thereby engendering frustration. Previously, an asymmetry in the linear elastic response was identified at the rigidity transition between compression and dilation. Here we show that the asymmetry extends away from the transition point for finite strains. Under finite compression, an initially solid VM can completely relax perimeter tension, resulting in a drop discontinuity in the mechanical response. Conversely, an initially floppy VM under dilation can rigidify and have a higher response. These observations imply that re-scaling of cell area shifts the transition between rigid and floppy states. Based on this insight, we calculate the re-scaling of cell area engendered by intrinsic curvature and write a prediction for the rigidity transition in the presence of curvature. The shift of the rigidity transition in the presence of curvature for the VM provides a new metric for predicting tissue rigidity from image data of curved tissues in a manner analogous to the flat case.

Overview on novel strategies and current guidelines for hematopoietic stem cell mobilisation and collection.

The success of the autologous stem cell transplantation is strictly related to an adequate hematopoietic stem cell mobilization and collection. The minimum threshold for a successful mobilization is currently defined as 2 × 106/kg CD34+ cells. However, the optimal stem cell mobilization strategy is still controversial. The availability of plerixafor, a selective and reversible CXCR4 inhibitor, has been associated with an higher use of chemo-free protocols by many centres. In the near future, it is conceivable that artificial intelligence may became more accurate and comprehensive, possibly guiding clinicians in choosing the optimal mobilisation treatment for the various patients undergoing hematopoietic stem cell transplantation. Machine learning-based scoring models may be the basis for the development of "intelligent" mobilisation algorithms.

Vorticity phase separation and defect lattices in the isotropic phase of active liquid crystals.

We use numerical simulations and linear stability analysis to study the dynamics of an active liquid crystal film on a substrate in the regime where the passive system would be isotropic. Extensile activity builds up local orientational order and destabilizes the quiescent isotropic state above a critical activity, eventually resulting in spatiotemporal chaotic dynamics akin to the one observed ubiquitously in the nematic state. Here we show that tuning substrate friction yields a variety of emergent structures at intermediate activity, including lattices of flow vortices with associated regular arrangements of topological defects and a new state where flow vortices trap pairs of +1/2 defect that chase each other's tail. These chiral units spontaneously pick the sense of rotation and organize in a hexagonal lattice, surrounded by a diffuse flow of opposite rotation to maintain zero net vorticity. The length scale of these emergent structures is set by the screening length of the flow, controlled by the shear viscosity η and the substrate friction Γ, and can be captured by simple mode selection of the vortical flows. We demonstrate that the emergence of coherent structures can be interpreted as a phase separation of vorticity, where friction plays a role akin to that of birth/death processes in breaking conservation of the phase separating species and selecting a characteristic scale for the patterns. Our work shows that friction provides an experimentally accessible tuning parameter for designing controlled active flows.

Controlling liquid-liquid phase behaviour with an active fluid.

Demixing binary liquids is a ubiquitous transition explained using a well-established thermodynamic formalism that requires the equality of intensive thermodynamics parameters across phase boundaries. Demixing transitions also occur when binary fluid mixtures are driven away from equilibrium, but predicting and designing such out-of-equilibrium transitions remains a challenge. Here we study the liquid-liquid phase separation of attractive DNA nanostars driven away from equilibrium using a microtubule-based active fluid. We find that activity lowers the critical temperature and narrows the range of coexistence concentrations, but only in the presence of mechanical bonds between the liquid droplets and reconfiguring active fluid. Similar behaviours are observed in numerical simulations, suggesting that the activity suppression of the critical point is a generic feature of active liquid-liquid phase separation. Our work describes a versatile platform for building soft active materials with feedback control and providing an insight into self-organization in cell biology.

Cost-Effectiveness of brexucabtagene autoleucel for relapsed/refractory mantle cell lymphoma.

Brexucabtagene autoleucel is a chimeric anti CD19 antigen receptor T-cell therapy that allows durable responses in relapsed/refractory (R/R) mantle cell lymphoma (MCL). The present study compared the clinical and economic outcomes of R/R MCL patients (pre-exposed to ibrutinib and chemoimmunotherapy) treated with brexucabtagene autoleucel versus Rituximab, bendamustine, cytarabine (R-BAC) in the Italian Healthcare System. A partitioned-survival model extrapolated survival and healthcare costs of R/R MCL patients over a lifetime horizon. Discounted and quality-adjusted life expectancy (QALY) was 6.40 versus 1.20 for brexucabtagene autoleucel versus R-BAC and lifetime costs were €411,403 versus €74,415, respectively, which corresponds to a cost of €64,798 per QALY gained. The results were highly sensitive to brexucabtagene autoleucel acquisition cost and to assumptions on long-term survival, therefore the cost-effectiveness of brexucabtagene autoleucel for patients with R/R MCL requires validation with longer follow-up data and in specific risk subgroups.

Reduction of double chin without surgery using ascorbic acid and ascorbyl-palmitate solution: a clinical study.

OBJECTIVE: The purpose of the present clinical study is to assess the effectiveness of a lipolytic solution containing sodium salt of ascorbic acid at 0.24% and a surfactant agent at 0.020% ascorbyl-palmitate (SAP) for the treatment of double chin. PATIENTS AND METHODS: A total of 10 healthy adult subjects affected by double chin (8 female and 2 male) were evaluated in the present investigation. The patients were admitted to a total of 4 sessions, with biweekly procedures, without no other active agents addiction. RESULTS: In all the subjects a reduction of the convexity of the chin after the treatment with SAP was observed. Improvement in submental appearance was achieved in 90% (9/10) of the patients. One patient did not see any improvement in submental appearance after two section treatments and withdrew from the treatment. CONCLUSIONS: In conclusion, in the present study, a new adipocytolytic solution consisting of sodium ascorbate mixed with ascorbyl-palmitate was used with success as a surfactant agent for the treatment of double chin.

Evaluation of the efficacy and safety of hyaluronic acid and supplemented with amino acids, and glutathione or colin, for the prevention and treatment of wrinkles on the face, neck, décolleté and hands.

OBJECTIVE: Hyaluronic acid has been used for a long time as a biorevitalizer to treat skin aging both in single formulation and in association with other compounds such as amino acids or vitamins. The purpose of this study was to evaluate the efficacy and safety of class III medical devices SKIN B, SKIN R, SKIN OX, SKIN COLIN, for the treatment of wrinkles on the face, neck, décolleté and hands. These medical devices are all based on hyaluronic acid and supplemented with amino acids (SKIN B and SKIN R) and glutathione (SKIN OX) or colin (SKIN COLIN). This gives broader possibilities to the aesthetic surgeon for personalization and pharmacological diversification based on the patient's deficits to treat. PATIENTS AND METHODS: A total of 60 subjects affected by skin damage such as rhytidids, dehydration, reduced sebum production and skin hypoxia were enrolled. The patients were treated with a session of mesotherapy every 7 days for 30 days, followed by other 2 sessions every 15 days for 30 days and the follow-up on day 90. The primary efficacy endpoint was evaluated by means of a 0-10 visual analog scale at day 60; the secondary efficacy endpoint was evaluated by means of a 0-10 visual analog scale at day 90. RESULTS: All patients completed the 3-month follow-up. Treatment with SKIN B, SKIN OX, SKIN COLIN and SKIN R medical devices for the prevention and treatment of wrinkles on the face, neck, décolleté and hands were associated with favorable and positive results. A clear reduction of wrinkles has been clinically observed with improvement in the texture, brightness, and turgor of the skin. No adverse events were reported. CONCLUSIONS: The medical devices SKIN B, SKIN SKIN OX, SKIN COLIN produce an aesthetic improvement in patients affected by skin defects, when administered by mesotherapy technique. This study confirms the safety and efficacy of the medical devices based on hyaluronic acid supplemented with amino acids and glutathione or colin.

The role of non-affine deformations in the elastic behavior of the cellular vertex model.

The vertex model of epithelia describes the apical surface of a tissue as a tiling of polygonal cells, with a mechanical energy governed by deviations in cell shape from preferred, or target, area, A0, and perimeter, P0. The model exhibits a rigidity transition driven by geometric incompatibility as tuned by the target shape index, . For with p*(6) the perimeter of a regular hexagon of unit area, a cell can simultaneously attain both the preferred area and preferred perimeter. As a result, the tissue is in a mechanically soft compatible state, with zero shear and Young's moduli. For p0 < p*(6), it is geometrically impossible for any cell to realize the preferred area and perimeter simultaneously, and the tissue is in an incompatible rigid solid state. Using a mean-field approach, we present a complete analytical calculation of the linear elastic moduli of an ordered vertex model. We analyze a relaxation step that includes non-affine deformations, leading to a softer response than previously reported. The origin of the vanishing shear and Young's moduli in the compatible state is the presence of zero-energy deformations of cell shape. The bulk modulus exhibits a jump discontinuity at the transition and can be lower in the rigid state than in the fluid-like state. The Poisson's ratio can become negative which lowers the bulk and Young's moduli. Our work provides a unified treatment of linear elasticity for the vertex model and demonstrates that this linear response is protocol-dependent.

Patterning of morphogenetic anisotropy fields.

Orientational order, encoded in anisotropic fields, plays an important role during the development of an organism. A striking example of this is the freshwater polyp Hydra, where topological defects in the muscle fiber orientation have been shown to localize to key features of the body plan. This body plan is organized by morphogen concentration gradients, raising the question how muscle fiber orientation, morphogen gradients and body shape interact. Here, we introduce a minimal model that couples nematic orientational order to the gradient of a morphogen field. We show that on a planar surface, alignment to a radial concentration gradient can induce unbinding of topological defects, as observed during budding and tentacle formation in Hydra, and stabilize aster/vortex-like defects, as observed at a Hydra's mouth. On curved surfaces mimicking the morphologies of Hydra in various stages of development-from spheroid to adult-our model reproduces the experimentally observed reorganization of orientational order. Our results suggest how gradient alignment and curvature effects may work together to control orientational order during development and lay the foundations for future modeling efforts that will include the tissue mechanics that drive shape deformations.

Defect self-propulsion in active nematic films with spatially varying activity.

We study the dynamics of topological defects in active nematic films with spatially varying activity and consider two set-ups: (i) a constant activity gradient and (ii) a sharp jump in activity. A constant gradient of extensile (contractile) activity endows the comet-like +1/2 defect with a finite vorticity that drives the defect to align its nose in the direction of decreasing (increasing) gradient. A constant gradient does not, however, affect the known self-propulsion of the +1/2 defect and has no effect on the -1/2 that remains a non-motile particle. A sharp jump in activity acts like a wall that traps the defects, affecting the translational and rotational motion of both charges. The +1/2 defect slows down as it approaches the interface and the net vorticity tends to reorient the defect polarization so that it becomes perpendicular to the interface. The -1/2 defect acquires a self-propulsion towards the activity interface, while the vorticity-induced active torque tends to align the defect to a preferred orientation. This effective attraction of the negative defects to the wall is consistent with the observation of an accumulation of negative topological charge at both active/passive interfaces and physical boundaries.

3D Whole-body skin imaging for automated melanoma detection.

BACKGROUND: Existing artificial intelligence for melanoma detection has relied on analysing images of lesions of clinical interest, which may lead to missed melanomas. Tools analysing the entire skin surface are lacking. OBJECTIVES: To determine if melanoma can be distinguished from other skin lesions using data from automated analysis of 3D-images. METHODS: Single-centre, retrospective, observational convenience sample of patients diagnosed with melanoma at a tertiary care cancer hospital. Eligible participants were those with a whole-body 3D-image captured within 90 days prior to the diagnostic skin biopsy. 3D-images were obtained as standard of care using VECTRA WB360 Whole Body 3-dimensional Imaging System (Canfield Scientific). Automated data from image processing (i.e. lesion size, colour, border) for all eligible participants were exported from VECTRA DermaGraphix research software for analysis. The main outcome was the area under the receiver operating characteristic curve (AUC). RESULTS: A total of 35 patients contributed 23,538 automatically identified skin lesions >2 mm in largest diameter (102-3021 lesions per participant). All were White patients and 23 (66%) were males. The median (range) age was 64 years (26-89). There were 49 lesions of melanoma and 22,489 lesions that were not melanoma. The AUC for the prediction model was 0.94 (95% CI: 0.92-0.96). Considering all lesions in a patient-level analysis, 14 (28%) melanoma lesions had the highest predicted score or were in the 99th percentile among all lesions for an individual patient. CONCLUSIONS: In this proof-of-concept pilot study, we demonstrated that automated analysis of whole-body 3D-images using simple image processing techniques can discriminate melanoma from other skin lesions with high accuracy. Further studies with larger, higher quality, and more representative 3D-imaging datasets would be needed to improve and validate these results.

Overview of the European species of the genus Clitocella (Entolomataceae, Agaricales) with notes on extralimital taxa.

A revision, based on morphological and multigene analysis, of the Clitocella species currently present in Europe is provided. Portions of nrITS rDNA, nr28S rDNA (LSU), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-alpha (EF-1α), and ATPase subunit 6 (ATP6), were used to sort out the relationships of the species within the genus. Three subgenera were recognized: Clitocella subg. Clitocella encompassing C. popinalis, C. colorata, C. mundula, C. nigrescens, C. obscura and the new species C. solaris from Switzerland; the new Clitocella subg. Paraclitopilus including C. fallax and C. blancii; and the new Clitocella subg. Rhodopleurella for accommodating C. termitophila, a peculiar entity characterized by a pleurotoid habit and growing on decaying, abandoned termite nests in the Dominican Republic. Clitocella colorata originally described from China is here reported and described for the first time in Europe (Italy and Estonia). Rhodocybe cupressicola and Clitopilus ammophilus are reduced to later synonyms of Rhodopaxillus nigrescens; similarly, Clitopilus amarus is treated as a later synonym of Omphalia fallax while Rhodocybe amarella and R. ochraceopallida of Rhodopaxillus blancii. Finally, Austrian and Swedish herbarium collections identified as Rhodocybe, a doubtful taxon considered by several modern authors occasionally as either a similar but distinct species from R. popinalis or as a dwarfish, puny and odourless form of R. popinalis, have been proved to be R. tugrulii, a species recently described from Turkey and Estonia, and also later reported from Italy and USA. Citation: Vizzini A, Consiglio G, Marchetti M. 2023. Overview of the European species of the genus Clitocella (Entolomataceae, Agaricales) with notes on extralimital taxa. Persoonia 50: 123-157. https://doi.org/10.3767/persoonia.2023.50.04.

Engineering tools for quantifying and manipulating forces in epithelia.

The integrity of epithelia is maintained within dynamic mechanical environments during tissue development and homeostasis. Understanding how epithelial cells mechanosignal and respond collectively or individually is critical to providing insight into developmental and (patho)physiological processes. Yet, inferring or mimicking mechanical forces and downstream mechanical signaling as they occur in epithelia presents unique challenges. A variety of in vitro approaches have been used to dissect the role of mechanics in regulating epithelia organization. Here, we review approaches and results from research into how epithelial cells communicate through mechanical cues to maintain tissue organization and integrity. We summarize the unique advantages and disadvantages of various reduced-order model systems to guide researchers in choosing appropriate experimental systems. These model systems include 3D, 2D, and 1D micromanipulation methods, single cell studies, and noninvasive force inference and measurement techniques. We also highlight a number of in silico biophysical models that are informed by in vitro and in vivo observations. Together, a combination of theoretical and experimental models will aid future experiment designs and provide predictive insight into mechanically driven behaviors of epithelial dynamics.

Active nematic defects in compressible and incompressible flows.

We study the dynamics of active nematic films on a substrate driven by active flows with or without the incompressible constraint. Through simulations and theoretical analysis, we show that arch patterns are stable in the compressible case, while they become unstable under the incompressibility constraint. For compressible flows at high enough activity, stable arches organize themselves into a smecticlike pattern, which induce an associated global polar ordering of +1/2 nematic defects. By contrast, divergence-free flows give rise to a local nematic order of the +1/2 defects, consisting of antialigned pairs of neighboring defects, as established in previous studies.

Local Yield and Compliance in Active Cell Monolayers.

The rheology of biological tissue plays an important role in many processes, from organ formation to cancer invasion. Here, we use a multiphase field model of motile cells to simulate active microrheology within a tissue monolayer. When unperturbed, the tissue exhibits a transition between a solidlike state and a fluidlike state tuned by cell motility and deformability-the ratio of the energetic costs of steric cell-cell repulsion and cell-edge tension. When perturbed, solid tissues exhibit local yield-stress behavior, with a threshold force for the onset of motion of a probe particle that vanishes upon approaching the solid-to-liquid transition. This onset of motion is qualitatively different in the low and high deformability regimes. At high deformability, the tissue is amorphous when solid, it responds compliantly to deformations, and the probe transition to motion is smooth. At low deformability, the monolayer is more ordered translationally and stiffer, and the onset of motion appears discontinuous. Our results suggest that cellular or nanoparticle transport in different types of tissues can be fundamentally different and point to ways in which it can be controlled.

Dynamics of active liquid interfaces.

Controlling interfaces of phase-separating fluid mixtures is key to the creation of diverse functional soft materials. Traditionally, this is accomplished with surface-modifying chemical agents. Using experiment and theory, we studied how mechanical activity shapes soft interfaces that separate an active and a passive fluid. Chaotic flows in the active fluid give rise to giant interfacial fluctuations and noninertial propagating active waves. At high activities, stresses disrupt interface continuity and drive droplet generation, producing an emulsion-like active state composed of finite-sized droplets. When in contact with a solid boundary, active interfaces exhibit nonequilibrium wetting transitions, in which the fluid climbs the wall against gravity. These results demonstrate the promise of mechanically driven interfaces for creating a new class of soft active matter.