Hemisilicone Elastomers That Are Recyclable to the Monomer.

Methyl-, vinyl-, and hydride-terminated polymers of the heterocyclic monomer, 2,2,5,5-tetramethyl-2,5-disila-1-oxacyclopentane (-ME) were prepared by sulfuric acid-catalyzed, ring-opening equilibration with the end-capping agents hexamethyldisiloxane (MM), divinyltetramethyldisiloxane (MM), and tetramethyldisiloxane (MM), respectively. The molecular weights of the polymers were controlled by adjusting the ratio of monomer to end-capping agent. All of these polymers are oils and exhibit molecular weight-dependent viscosities that are qualitatively similar to those of polydimethylsiloxane (PDMS)-based analogs prepared by the same reaction using octamethylcyclotetrasiloxane (D) instead of -ME.

Rediscovering Silicones: The Anomalous Water Permeability of "Hydrophobic" PDMS Suggests Nanostructure and Applications in Water Purification and Anti-Icing.

Cross-linked polydimethylsiloxane (PDMS) is simultaneously water-repellent and highly permeable to water vapor. Unfilled and silica-free cross-linked PDMS films of variable thickness (8-160 µm) are prepared and their water vapor transmission rates and permeability values are determined. Vapor transmission rate increases as membrane thickness decreased from 160 to 15 µm, but does not increase further when the film thickness is decreased to 8 µm.

A Different Silica Surface: Radical Oxidation of Poly(methylsilsesquioxane) Thin Films and Particles (Tospearl).

Surfaces that exhibit the reactivity of silica toward surface modification (silanol condensation) were prepared by treating thin films and particles of poly(methylsilsesquioxane) with aqueous potassium persulfate at elevated temperature. Parallel experiments were carried out using a highly cross-linked poly(dimethylsiloxane). Advancing (θ) and receding (θ) water contact angles for all of these oxidized surfaces were θ/θ = ∼10/∼0°, and these low values remain unchanged for months.

Identifying Injury Patterns Associated With Physical Elder Abuse: Analysis of Legally Adjudicated Cases.

Study Objective: Elder abuse is common and has serious health consequences but is underrecognized by health care providers. An important reason for this is difficulty in distinguishing between elder abuse and unintentional trauma. Our goal was to identify injury patterns associated with physical elder abuse in comparison with those of patients presenting to the emergency department (ED) with unintentional falls.

Sessile Liquid Features as Molds for Silicone Elastomers.

Liquid applied to a chemically patterned (wetting/nonwetting, lyophilic/lyophobic) substrate forms a 3-dimensional contoured surface, the shape of which depends on the volume of liquid applied and the shape of the three-phase contact lines of air (or other phase in contact), liquid, and the wetted pattern. The resulting binary contoured interface with air, which consists of flat unwetted regions of the substrate and the mean curvature liquid-vapor interfaces of the sessile structures, can be used as a mold for imprinting solid polymers by curing liquid resins in contact. The success, flexibility with regard to shape, and reproducibility of this molding process depend on numerous issues.

Carbon Nanotubes Readily Disperse in Linear Silicones and Improve the Thermal Stability of Dimethylsilicone Elastomers.

Stable silicone fluid-carbon nanotube dispersions were prepared in minutes by simple mixing processes, without the addition of solvents or surfactants and without the chemical modification of the nanotubes. With linear silicones of sufficient viscosity, a dual asymmetric centrifuge (SpeedMixer) was sufficient for dispersion; lower viscosity silicones required a brief ultrasound treatment. Optical microscopy indicates a homogeneous dispersion of multiwalled carbon nanotube (MWCNT) bundles in linear poly(dimethylsiloxane) (PDMS) oils.

Near infrared light amplifies endothelial progenitor cell accumulation after stroke.

Damage-associated molecular pattern signals may play key roles in mediating non-cell autonomous effects of pre and post-conditioning. Here, we show that near-infrared (NIR) light stimulation of astrocytes increases a calcium-dependent secretion of the prototypical DAMP, HMGB1, which may then accelerate endothelial progenitor cell (EPC) accumulation after stroke. Conditioned media from NIR-stimulated astrocytes increased EPC proliferation in vitro, and blockade of HMGB1 with siRNA diminished the effect.

Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs.

Difflugia are testate amoebae that use particulate inorganic matter to build a protective shell (generally called a test or theca). Difflugia globulosa were grown both in culture containing only naturally occurring theca-building materials and under conditions where synthetic particles were present also. The presence of monodisperse Stöber silica microspheres of 1, 3, and 6 μm in diameter or 4 μm polystyrene spheres dramatically increased the rate of Difflugia growth, and foreign microspheres became the overwhelmingly dominant construction material.

Emergency department provider perspectives on elder abuse and development of a novel ED-based multidisciplinary intervention team.

Background: An ED visit provides a unique opportunity to identify elder abuse, which is common and has serious medical consequences. Despite this, emergency providers rarely recognise or report it. We have begun the design of an ED-based multidisciplinary consultation service to improve identification and provide comprehensive medical and forensic assessment and treatment for potential victims.

Melatonin and Sleep in Preventing Hospitalized Delirium: A Randomized Clinical Trial.

Purpose: Studies suggest that melatonin may prevent delirium, a condition of acute brain dysfunction occurring in 20%-30% of hospitalized older adults that is associated with increased morbidity and mortality. We examined the effect of melatonin on delirium prevention in hospitalized older adults while measuring sleep parameters as a possible underlying mechanism.

Methods: This was a randomized clinical trial measuring the impact of 3 mg of melatonin nightly on incident delirium and both objective and subjective sleep in inpatients age ≥65 years, admitted to internal medicine wards (non-intensive care units).

Superhydrophobic, Low-Hysteresis Patterning Chemistry for Water-Drop Manipulation.

A method for preparing superhydrophobic surfaces containing guiding lines that control water motion is described. The background surfaces exhibit contact angles of θ/θ = 173°/171°, and the guiding lines are also hydrophobic (θ/θ = 104°/102°). The low-contact-angle hysteresis allows facile water motion.

Rapid and Clean Covalent Attachment of Methylsiloxane Polymers and Oligomers to Silica Using B(CF) Catalysis.

The rapid, room-temperature covalent attachment of alkylhydridosilanes (RSi-H) to silicon oxide surfaces to form monolayers using tris(pentafluorophenyl)borane (B(CF), BCF) catalysis has recently been described. This method, unlike alternative routes to monolayers, produces only unreactive H gas as a byproduct and reaches completion within minutes. We report the use of this selective reaction between surface silanols and hydridosilanes to prepare surface-grafted poly(dimethylsiloxane)s (PDMSs) with various graft architectures that are controlled by the placement of hydridosilane functionality at one end, both ends, or along the chain of PDMS samples of controlled molecular weight.

Emergency Medical Services Perspectives on Identifying and Reporting Victims of Elder Abuse, Neglect, and Self-Neglect.

Background: Emergency Medical Services (EMS) providers, who perform initial assessments of ill and injured patients, often in a patient's home, are uniquely positioned to identify potential victims of elder abuse, neglect, or self-neglect. Despite this, few organized programs exist to ensure that EMS concerns are communicated to or further investigated by other health care providers, social workers, or the authorities.

Objective: To explore attitudes and self-reported practices of EMS providers surrounding identification and reporting of elder mistreatment.

Achieving high aspect ratio wrinkles by modifying material network stress.

Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate.

Describing visible acute injuries: development of a comprehensive taxonomy for research and practice.

Background: Little literature exists classifying and comprehensively describing intentional and unintentional acute injuries, which would be valuable for research and practice. In preparation for a study of injury patterns in elder abuse, our goal was to develop a comprehensive taxonomy of relevant types and characteristics of visible acute injuries and evaluate it in geriatric patients.

Methods: We conducted an exhaustive review of the medical and forensic literature focusing on injury types, descriptions, patterns and analyses.

Radiologists' Training, Experience, and Attitudes About Elder Abuse Detection.

Objective: Elder abuse is underrecognized, and identification of subtle cases requires a high index of suspicion among all health care providers. Because many geriatric injury victims undergo radiographic imaging, diagnostic radiologists may be well positioned to identify injury patterns suggestive of abuse. Little is known about radiologists' experience with elder abuse.

Sulfone-Containing Methacrylate Homopolymers: Wetting and Thermal Properties.

Although the sulfonyl functional group has a large dipole moment and compounds containing them (sulfones) have correspondingly high dielectric constants, this chemical structure has been neglected for use as a functional group to render surfaces hydrophilic. We have prepared three methacrylate polymers containing side chains capped with sulfolane, methylsulfone, and ethylsulfone functionality. The sulfolane-containing polymer exhibits an unusually high glass transition temperature (Tg = 188°C) for a methacrylate polymer and slightly different thermal degradation behavior than the other two sulfone-containing polymers, likely due to the bulky structure of the sulfolane group in the polymer side chain.

Covalently Attached Liquids: Instant Omniphobic Surfaces with Unprecedented Repellency.

Recent strategies to prepare "omniphobic" surfaces have demonstrated that minimizing contact angle hysteresis (CAH) is the key criterion for effectiveness. CAH is affected by chemistry and topography defects at the molecular and higher levels, thus most surfaces exhibit significant CAH. Preparative methods for stable coatings on smooth substrates with negligible CAH (<2°) for a broad range of liquids have not been reported.

Near infrared radiation protects against oxygen-glucose deprivation-induced neurotoxicity by down-regulating neuronal nitric oxide synthase (nNOS) activity in vitro.

Near infrared radiation (NIR) has been shown to be neuroprotective against neurological diseases including stroke and brain trauma, but the underlying mechanisms remain poorly understood. In the current study we aimed to investigate the hypothesis that NIR may protect neurons by attenuating oxygen-glucose deprivation (OGD)-induced nitric oxide (NO) production and modulating cell survival/death signaling. Primary mouse cortical neurons were subjected to 4 h OGD and NIR was applied at 2 h reoxygenation.

Capillary-bridge-derived particles with negative Gaussian curvature.

We report the preparation of millimeter-scale particles by thermal polymerization of liquid monomer capillary bridges to form catenoid-shaped particles that exhibit negative Gaussian curvature. The shape of the capillary bridges and resulting particles can be finely tuned using several addressable parameters: (i) the shape, size, and orientation of lithographic pinning features on the spanned surfaces; (ii) the distance between opposing support surfaces; and (iii) the lateral displacement (shear) of opposing features. The catenoid-shaped particles exhibit controllable optical properties as a result of their concave menisci, the shape of which can be easily manipulated.

Simple and improved approaches to long-lasting, hydrophilic silicones derived from commercially available precursors.

Three types of commercially derived methylsilicone materials, Sylgard-184, Q(V)Q(H) (an MQ-based silicone containing no dimethylsiloxane, D units), and D(V)D(H) (a D-based silicone with no additives), were judiciously chosen to study the conditions under which long-lasting hydrophilicity after oxygen plasma treatment can be obtained. A 30 s plasma treatment time under controlled conditions was found to be optimal in terms of achieving the lowest initial advancing and receding contact angles of θ(A)/θ(R) = 10°/5° with undetectable surface damage. Vacuum treatment, a necessary step prior to plasma ignition that has been overlooked in previous studies, as well as room temperature curing were explored as means to remove low molecular weight species.

Liquid marbles supported by monodisperse poly(methylsilsesquioxane) particles.

The preparation of model, well-controlled colloidal assemblies has been a central approach to understanding and optimizing the characteristics and functionality of complex colloidal dispersion systems. This approach, which has created a significant literature and rather deep understanding for emulsions and foams, has yet to be established for the liquid marble (water-in-air) motif. In this article we report the preparation of well-controlled liquid marbles using monodisperse micron-size particles of poly(methylsilsesquioxane) (PMSQ).

Near infrared radiation rescues mitochondrial dysfunction in cortical neurons after oxygen-glucose deprivation.

Near infrared radiation (NIR) is known to penetrate and affect biological systems in multiple ways. Recently, a series of experimental studies suggested that low intensity NIR may protect neuronal cells against a wide range of insults that mimic diseases such as stroke, brain trauma and neurodegeneration. However, the potential molecular mechanisms of neuroprotection with NIR remain poorly defined.

Dip-coating deposition on chemically patterned surfaces: a mechanistic analysis and comparison with topographically patterned surfaces.

Chemically patterned surfaces containing hydrophilic features on a hydrophobic background have been used by a number of groups to deposit arrays of particles/crystals/substances by dip-coating deposition. In this technique, a substrate is simply withdrawn from a solution (or dispersion) of the desired substance, the solution dewets from the hydrophobic region and wets the hydrophilic features, and the particles/crystals/substances deposit on the hydrophilic features after solvent evaporation. An apparently similar approach, recently described by several groups, involves dip-coating deposition of substances from solutions onto hydrophobic topographic features (arrays of posts on superhydrophobic surfaces) that are separated by air.