Phase separation dynamics in wetting ridges of polymer surfaces swollen with oils of different viscosities.

When drops are placed on a sufficiently soft surface, the drop surface tension drives an out of plane deformation around the contact line (, a wetting ridge). For soft elastomeric surfaces that are swollen with a liquid, capillarity from a drop can induce a phase separation in the wetting ridge. Using confocal microscopy, we study the dynamics of phase separation at the wetting ridge of glycerol drops on silicone elastomers, which are swollen with silicone oils of varying viscosity (, molecular weight).

Wetting on silicone surfaces.

Silicone is frequently used as a model system to investigate and tune wetting on soft materials. Silicone is biocompatible and shows excellent thermal, chemical, and UV stability. Moreover, the mechanical properties of the surface can be easily varied by several orders of magnitude in a controlled manner.

Controlling Anti-Penetration Performance by Post-Grafting of Fluorinated Alkyl Chains onto Polystyrene--poly(vinyl methyl siloxane).

Polydimethylsiloxane (PDMS) has been widely used as a surface coating material, which has been reported to possess dynamic omniphobicity to a wide range of both polar and nonpolar solvents due to its high segmental flexibility and mobility. However, such high flexibility and mobility also enable penetration of small molecules into PDMS coatings, which alter the chemical and physical properties of the coating layers. To improve the anti-penetration properties of PDMS, a series of fluorinated alkyl segments are grafted to a diblock copolymer of polystyrene--poly(vinyl methyl siloxane) (PS--PVMS) using thiol-ene click reactions.

27-year trends in incidence rates for testis cancer across a large statewide registry.

Purpose: To review 27-years of testicular cancer (TC) incidence data (1990-2017) within the state of Pennsylvania to better define incidence, geographic distribution, and trends over time.

Methods: The Pennsylvania Cancer Registry was reviewed for statewide and component county age-adjusted TC incidence rates and stage distribution. We reported annual percent changes (APCs) in age-adjusted rates.

Effectiveness and Safety of Antiobesity Medications in Patients With Obesity and Inflammatory Bowel Disease.

Introduction: Limited data exist evaluating antiobesity medications (AOM) in patients with inflammatory bowel disease (IBD).

Methods: We performed a case-control study evaluating the effectiveness and safety of AOM in patients with IBD with obesity, matched to non-IBD controls.

Results: After 12 months, the case (n = 36) and control (n = 36) groups achieved similar percent total body weight loss of -6.

Visualizing Penetration of Fluorescent Dye through Polymer Coatings.

Understanding how small molecules penetrate and contaminate polymer films is of vital importance for developing protective coatings for a wide range of applications. To this end, rhodamine B fluorescent dye is visualized diffusing through polystyrene-polydimethylsiloxane block copolymer (BCP) coatings using confocal microscopy. The intensity of dye inside the coatings grows and decays non-monotonically, which is likely due to a combination of dye molecule transport occurring concurrently in different directions.

Capillary detachment of a microparticle from a liquid-liquid interface.

The attachment and detachment of microparticles at a liquid-liquid interface are common in many material systems, from Pickering emulsions and colloidal assemblies to capillary suspensions. Properties of these systems rely on how the particles interact with the liquid-liquid interface, including the detachment process. In this study, we simultaneously measure the capillary detachment force of a microparticle from a liquid-liquid interface and visualize the shape of the meniscus by combining colloidal probe microscopy and confocal microscopy.

Engineering ligand reactivity enables high-temperature operation of stable perovskite solar cells.

Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically.

Creasing in microscale, soft static friction.

Utilizing colloidal probe, lateral force microscopy and simultaneous confocal microscopy, combined with finite element analysis, we investigate how a microparticle starts moving laterally on a soft, adhesive surface. We find that the surface can form a self-contacting crease at the leading front, which results from a buildup of compressive stress. Experimentally, creases are observed on substrates that exhibit either high or low adhesion when measured in the normal direction, motivating the use of simulations to consider the role of adhesion energy and interfacial strength.

Phase Separation in Wetting Ridges of Sliding Drops on Soft and Swollen Surfaces.

Drops in contact with swollen, elastomeric substrates can induce a capillary mediated phase separation in wetting ridges. Using confocal microscopy, we visualize phase separation of oligomeric silicone oil from a cross-linked silicone network during steady-state sliding of water drops. We find an inverse relationship between the oil tip height and the drop sliding speed, which is rationalized by competing transport timescales of the oil molecules: separation rate versus drop-advection speed.

Cronkhite-Canada syndrome: treatment responses and improved overall survival.

Background: Cronkhite-Canada syndrome (CCS) is considered a relentlessly progressive disease with high mortality rates. Although disease understanding and treatment options have greatly improved, the prognosis from these advancements has not been well documented. This study aimed to evaluate treatment outcomes and overall survival of CCS.

Synchronous melanosis of upper and lower urinary tract.

Urothelial melanosis is an exceptionally rare diagnosis, with less than 25 cases being reported in the literature. Melanosis of the urothelium is characterized by abnormal melanin deposition within tissues, producing a black, velvety appearance to the urothelial mucosa. We present a 67-year-old male undergoing cystoscopy during a routine percutaneous nephrolithotomy (PCNL), who was found to have diffuse bladder melanosis extending up the ureter and into the renal pelvis.

Shaping Nanoscale Ribbons into Microhelices of Controllable Radius and Pitch.

We report fabrication of highly flexible micron-sized helices from nanometer-thick ribbons. Building upon the helical coiling of such ultrathin ribbons mediated by surface tension, we demonstrate that the enhanced creep properties of highly confined materials can be leveraged to shape helices into the desired geometry with full control of the final shape. The helical radius, total length, and pitch angle are all freely and independently tunable within a wide range: radius within ∼1-100 μm, length within ∼100-3000 μm, and pitch angle within ∼0-70°.

Temperature-dependent soft wetting on amorphous, uncrosslinked polymer surfaces.

The wetting of polymer melts at high temperatures is studied by placing a glycerol drop on a poly(-butyl methacrylate) film and measuring the wetting ridge. The height of the wetting ridge grows continuously over time. These wetting ridge growth rates can be explained by polymer chain dynamics occurring at the molecular level, determined using oscillatory shear rheology of the polymer melt.

Erodible thermogelling hydrogels for localized mitochondrial transplantation to the spinal cord.

We developed a thermal-gelling, erodible hydrogel system for localized delivery of viable mitochondria in vivo, as well as labeled transplanted mitochondria with specific dyes and/or genetically modified mitochondria tagged with red fluorescence protein (RFP). We also employed cell lines to optimize a hydrogel composed of methylcellulose and hyaluronic acid designed to preserve bioenergetics while facilitating mitochondrial release. We further investigated how transplantation of allogeneic or xenogeneic mitochondria into respective cell lines affects host cellular metabolism, as measured by MTS assay.

Hydrophobic surface patterning with soft, wax-infused micro-stamps.

Hypothesis: Waxy hydrocarbons diffuse freely in polydimethylsiloxane (PDMS), and this capability can be leveraged to generate inexpensive surface micropatterns that modify adhesion and wetting.

Experiments: Patterns are created by placing a waxy Parafilm sheet on the back of a PDMS stamp containing microscale surface features. When heated, the paraffin liquefies and diffuses through the stamp, creating a thin liquid layer on the micropatterned stamp surface; when placed in contact with a target surface, the layer solidifies and is retained on the target when the stamp is removed.

Programmable Local Orientation of Micropores by Mold-Assisted Ice Templating.

Pore geometry plays a crucial role in determining the properties and functions of porous materials. Various methods have been developed to prepare porous materials that have randomly distributed or well-aligned pores. However, a technique capable of fine regulation of local pore orientation is still highly desired but difficult to attain.

Quantitative CT Predictors of Portal Venous Intervention in Uncontrolled Variceal Bleeding.

The purpose of this study was to quantify abdominal CT predictors of endoscopically refractory, uncontrolled variceal hemorrhage requiring portal venous intervention. From 2009 to 2018, 64 patients with endoscopically refractory variceal hemorrhage requiring portal venous intervention (variceal hemorrhage group) and 67 patients without hemorrhage but with symptomatic, pressure gradient-proven portal hypertension (control group) underwent CT. CT scans were retrospectively reviewed for the following: varix size, variceal intraluminal protrusion, liver and spleen volumes, and portal vein diameter.

Lifting a sessile oil drop from a superamphiphobic surface with an impacting one.

Colliding drops are encountered in everyday technologies and natural processes, from combustion engines and commodity sprays to raindrops and cloud formation. The outcome of a collision depends on many factors, including the impact velocity and the degree of alignment, and intrinsic properties like surface tension. Yet, little is known on binary impact dynamics of low-surface-tension drops on a low-wetting surface.

Cell Death Persists in Rapid Extrusion of Lysis-Resistant Coated Cardiac Myoblasts.

As the demand for organ transplants continues to grow faster than the supply of available donor organs, a new source of functional organs is needed. High resolution high throughput 3D bioprinting is one approach towards generating functional organs for transplantation. For high throughput printing, the need for increased print resolutions (by decreasing printing nozzle diameter) has a consequence: it increases the forces that cause cell damage during the printing process.

Capillary-driven indentation of a microparticle into a soft, oil-coated substrate.

Small scale contact between a soft, liquid-coated layer and a stiff surface is common in many situations, from synovial fluid on articular cartilage to adhesives in humid environments. Moreover, many model studies on soft adhesive contacts are conducted with soft silicone elastomers, which possess uncrosslinked liquid molecules (i.e.

Orthogonal photo-switching of supramolecular patterned surfaces.

We used Azo/α-CD and ipAzo/γ-CD host-guest complexes to demonstrate that four independent stable states can be orthogonally photo-switched by UV (365 nm), blue (470 nm), green (530 nm) and red light (625 nm). A supramolecular patterned surface was fabricated and orthogonally photo-switched by light with different wavelengths.

Spontaneous jumping, bouncing and trampolining of hydrogel drops on a heated plate.

The contact between liquid drops and hot solid surfaces is of practical importance for industrial processes, such as thermal spraying and spray cooling. The contact and bouncing of solid spheres is also an important event encountered in ball milling, powder processing, and everyday activities, such as ball sports. Using high speed video microscopy, we demonstrate that hydrogel drops, initially at rest on a surface, spontaneously jump upon rapid heating and continue to bounce with increasing amplitudes.

When the going gets rough - studying the effect of surface roughness on the adhesive abilities of tree frogs.

Tree frogs need to adhere to surfaces of various roughnesses in their natural habitats; these include bark, leaves and rocks. Rough surfaces can alter the effectiveness of their toe pads, due to factors such as a change of real contact area and abrasion of the pad epithelium. Here, we tested the effect of surface roughness on the attachment abilities of the tree frog .

Guiding cell migration with microscale stiffness patterns and undulated surfaces.

Unlabelled: By placing stiff structures under soft materials, prior studies have demonstrated that cells sense and prefer to position themselves over the stiff structures. However, an understanding of how cells migrate on such surfaces has not been established. Many studies have also shown that cells readily align to surface topography.