Shear thickening in suspensions of particles with dynamic brush layers.

Control of frictional interactions among liquid-suspended particles has led to tunable, strikingly non-Newtonian rheology the formation of strong flow constraints as particles come into close proximity under shear. Typically, these frictional interactions have been in the form of physical contact, controllable particle shape and surface roughness. We investigate a different route, where molecular bridging between nearby particle surfaces generates a controllable constraint to relative particle movement.

Faceted wrinkling by contracting a curved boundary.

Single-mode deformations of two-dimensional materials, such as the Miura-ori zig-zag fold, are important to the design of deployable structures because of their robustness; these usually require careful pre-patterning of the material. Here we show that inward contraction of a curved boundary produces a fine wrinkle pattern with a novel structure that suggests similar single-mode characteristics, but with minimal pre-patterning. Using finite-element representation of the contraction of a thin circular annular sheet, we show that these sheets wrinkle into a structure well approximated by an isometric structure composed of conical sectors and flat, triangular facets.

Nonhormonal Pharmacotherapies for the Treatment of Postmenopausal Vasomotor Symptoms.

An average of 60-80% of all menopausal women experience bothersome vasomotor symptoms (VMSs), such as flushing and sweating, within the first seven years of onset. However, despite increasing prevalence, these hot flashes remain hard to treat and have a negative effect on the quality of life. Though hormone replacement therapy is commonly utilized as a standard treatment for VMSs, this therapy is not recommended for all women.

Treatment modalities for infantile spasms: current considerations and evolving strategies in clinical practice.

Infantile spasms, newly classified as infantile epileptic spasm syndrome (IESS), occur in children under 2 years of age and present as an occur as brief, symmetrical, contractions of the musculature of the neck, trunk, and extremities. When infantile spasms occur with a concomitant hypsarrhythmia on electroencephalogram (EEG) and developmental regression, it is known as West Syndrome. There is no universally accepted mainstay of treatment for this condition, but some options include synthetic adrenocorticotropic hormone (ACTH), repository corticotropin injection (RCI/Acthar Gel), corticosteroids, valproic acid, vigabatrin, and surgery.

Granular convergence as an iterated local map.

Granular convergence is a property of a granular pack as it is repeatedly sheared in a cyclic, quasistatic fashion, as the packing configuration changes via discrete events. Under suitable conditions the set of microscopic configurations encountered converges to a periodic sequence after sufficient shear cycles. Prior work modeled this evolution as the iteration of a pre-determined, random map from a set of discrete configurations into itself.

Stochastic synchronization induced by noise.

Random perturbations applied in tandem to an ensemble of oscillating objects can synchronize their motion. We study multiple copies of an arbitrary dynamical system in a stable limit cycle, described via a standard phase reduction picture. The copies differ only in their arbitrary phases ϕ.

Transgender and Gender Diverse People's Fear of Seeking and Receiving Care in Later Life: A Multiple Method Analysis.

The purpose of the current research is to understand concerns about receiving care in a sample of transgender, gender nonbinary, and gender diverse (TGD) adults across the lifespan. A total of 829 participants, predominantly from the United States and Canada, aged 18-70, completed the (TMLS) section on caregiving and are included in this study. We found middle-aged adults, people of Color, and people living with a disability reported the highest level of concern for their ability to function independently because of financial resources, physical concerns, cognitive impairment, or a lack of someone to care for them.

Oxidative Stress and Inflammation Are Associated With Age-Related Endothelial Dysfunction in Men With Low Testosterone.

Context: Vascular aging, including endothelial dysfunction secondary to oxidative stress and inflammation, increases the risk for age-associated cardiovascular disease (CVD). Low testosterone in middle-aged/older men is associated with increased CVD risk.

Objective: We hypothesized that low testosterone contributes to age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation.

Assessment of macrovascular and microvascular function in aging males.

Aging is associated with reductions in endothelial function, observations primarily reported using brachial artery ultrasound. There is growing interest in the use of peripheral artery tonometry (PAT) of microvessels in the fingertip to assess endothelial function because it is less technically demanding and has a high sensitivity and specificity for assessing coronary endothelial function. Moreover, similar to brachial artery flow-mediated dilation (FMD), PAT predicts cardiovascular disease outcomes.

A review of shaped colloidal particles in fluids: anisotropy and chirality.

This review treats asymmetric colloidal particles moving through their host fluid under the action of some form of propulsion. The propulsion can come from an external body force or from external shear flow. It may also come from externally-induced stresses at the surface, arising from imposed chemical, thermal or electrical gradients.

Transgender and gender non-conforming adult preparedness for aging: Concerns for aging, and familiarity with and engagement in planning behaviors.

Research on transgender and gender-nonconforming (TGNC) aging is limited. To date, most of the literature about TGNC aging has focused on discrimination (particularly in healthcare), violence and abuse, caregiving and family relations, and religiosity. The purposes of this study were to: (a) document concerns about aging among TGNC adults, including concerns that are identity-specific; (b) examine preparation for aging and end of life (i.

Chiral motion in colloidal electrophoresis.

Asymmetrically charged, nonspherical colloidal particles in general perform complex rotations and oblique motions under an electric field. The interplay of electrostatic and hydrodynamic forces complicates the prediction of these motions. We demonstrate a method of calculating the body tensors that dictate translational and rotational velocity vectors arising from an external electric field.

Nucleation and shape dynamics of model nematic tactoids around adhesive colloids.

Recent experiments have shown how nematically ordered tactoid shaped actin droplets can be reorganized and divided by the action of myosin molecular motors. In this paper, we consider how similar morphological changes can potentially be achieved under equilibrium conditions. Using simulations, both atomistic and continuum, and a simple macroscopic model, we explore how the nucleation dynamics, shape changes, and the final steady state of a nematic tactoid droplet can be modified by interactions with model adhesive colloids that mimic a myosin motor cluster.

Cyclic annealing as an iterated random map.

Disordered magnets, martensitic mixed crystals, and glassy solids can be irreversibly deformed by subjecting them to external deformation. The deformation produces a smooth, reversible response punctuated by abrupt relaxation "glitches." Under appropriate repeated forward and reverse deformation producing multiple glitches, a strict repetition of a single sequence of microscopic configurations often emerges.

Self-organizing motors divide active liquid droplets.

The cytoskeleton is a collection of protein assemblies that dynamically impose spatial structure in cells and coordinate processes such as cell division and mechanical regulation. Biopolymer filaments, cross-linking proteins, and enzymatically active motor proteins collectively self-organize into various precise cytoskeletal assemblies critical for specific biological functions. An outstanding question is how the precise spatial organization arises from the component macromolecules.

Engineering single-polymer micelle shape using nonuniform spontaneous surface curvature.

Conventional micelles, composed of simple amphiphiles, exhibit only a few standard morphologies, each characterized by its mean surface curvature set by the amphiphiles. Here we demonstrate a rational design scheme to construct micelles of more general shape from polymeric amphiphiles. We replace the many amphiphiles of a conventional micelle by a single flexible, linear, block copolymer chain containing two incompatible species arranged in multiple alternating segments.

Mechanics of population aging and survival.

In this paper we extend the previous work of Witten and her team on defining a classical physics-driven model of survival in aging populations (Eakin, Bull Math Biol 56(6):1121-1141, 1994; Eakin and Witten, Mech Aging Dev 78(2):85-101, 1995; Witten and Eakin, Exp Gerontol 32(2):259-285, 1997) by revisiting the concept of a force of aging and introducing the concepts of a momentum of aging, a kinetic energy and a potential energy of an aging population. We further extend the analysis beyond the deterministic Newtonian mechanics of a macroscopic population as a whole by considering the probabilistic nature of survival of individual population cohort members, thus producing new statistical physics-based concepts of entropy and of a gerontological "temperature". These new concepts are then illustrated with application to the classic parametric Gompertz survival model, which is a commonly used empirical descriptor for survival dynamics of mammalian species, human populations in particular.

Predicting tensorial electrophoretic effects in asymmetric colloids.

We formulate a numerical method for predicting the tensorial linear response of a rigid, asymmetrically charged body to an applied electric field. This prediction requires calculating the response of the fluid to the Stokes drag forces on the moving body and on the countercharges near its surface. To determine the fluid's motion, we represent both the body and the countercharges using many point sources of drag known as Stokeslets.

Impact of Anticipated Bias from Healthcare Professionals on Perceived Successful Aging Among Transgender and Gender Nonconforming Older Adults.

Purpose: Transgender and gender nonconforming (TGNC) persons have routinely experienced high rates of violence and discrimination. Discrimination in healthcare can affect the ability of TGNC persons to age successfully as it often deters them from seeking care. The purpose of this study was to determine if anticipation of bias from healthcare professionals, as well as other variables, predicted perceived successful aging in a sample of TGNC adults.

Geometrical frustration yields fiber formation in self-assembly.

Controlling the self-assembly of supramolecular structures is vital for living cells, and a central challenge for engineering at the nano- and microscales [1, 2]. Nevertheless, even particles without optimized shapes can robustly form well-defined morphologies. This is the case in numerous medical conditions where normally soluble proteins aggregate into fibers [3, 4].

Self-folding origami at any energy scale.

Programmable stiff sheets with a single low-energy folding motion have been sought in fields ranging from the ancient art of origami to modern meta-materials research. Despite such attention, only two extreme classes of crease patterns are usually studied; special Miura-Ori-based zero-energy patterns, in which crease folding requires no sheet bending, and random patterns with high-energy folding, in which the sheet bends as much as creases fold. We present a physical approach that allows systematic exploration of the entire space of crease patterns as a function of the folding energy.

Screening, Hyperuniformity, and Instability in the Sedimentation of Irregular Objects.

We study the overdamped sedimentation of non-Brownian objects of irregular shape using fluctuating hydrodynamics. The anisotropic response of the objects to flow, caused by their tendency to align with gravity, directly suppresses concentration and velocity fluctuations. This allows the suspension to avoid the anomalous fluctuations predicted for suspensions of symmetric spheroids.

Liquid behavior of cross-linked actin bundles.

The actin cytoskeleton is a critical regulator of cytoplasmic architecture and mechanics, essential in a myriad of physiological processes. Here we demonstrate a liquid phase of actin filaments in the presence of the physiological cross-linker, filamin. Filamin condenses short actin filaments into spindle-shaped droplets, or tactoids, with shape dynamics consistent with a continuum model of anisotropic liquids.

Prevalence of Antimicrobial Use and Opportunities to Improve Prescribing Practices in U.S. Nursing Homes.

Objectives: To describe the prevalence and epidemiology of antimicrobial use (AU) in nursing home residents.

Design: One-day point prevalence survey.

Setting And Participants: Nine nursing homes in four states; 1,272 eligible residents.