Self-Assembled Asperities for Pressure-Tunable Adhesion.

Control of adhesion is important in a host of applications including soft robotics, pick-and-place manufacturing, wearable devices, and transfer printing. While there are adhesive systems with discrete switchability between states of high and low adhesion, achieving continuously variable adhesion strength remains a challenge. In this work, a pressure-tunable adhesive (PTA) that is based on the self-assembly of stiff microscale asperities on an elastomeric substrate is presented.

Discrimination and Rejection: The Effects of Ethnic and Sexuality-Based Discrimination Against Latino Gay and Bisexual Men.

Latino gay and bisexual men (GBM) may experience discrimination attributed to their sexual orientation and ethnicity, necessitating an examination of their experiences from an intersectional lens. While relationships between discrimination and the internalization of those messages have been previously researched, less is known about experiencing discrimination attributed to different identities and its relationships with discrete attributions of internalized stigma. Understanding how different attributes of identity-based discrimination are related to different attributes of identity-based internalization of stigma among gay and bisexual men of color may be important in the design of interventions to help Latino GBM cope with discrimination and prevent negative mental health outcomes.

Preventing Catastrophic Failure of Microfibrillar Adhesives in Compliant Systems Based on Statistical Analysis of Adhesive Strength.

Adhesives based on fibrillar surface microstructures have shown great potential for handling applications requiring strong, reversible, and switchable adhesion. Recently, the importance of the statistical distribution of adhesive strength of individual fibrils in controlling the overall performance was revealed. Strength variations physically correspond to different interfacial defect sizes, which, among other factors, are related to surface roughness.

Yang-Mills structure for electron-phonon interactions in vanadium dioxide.

This work presents a method of grouping the electron spinors and the phonon modes of metal oxide crystals such as vanadium dioxide into an SU(2) gauge theory. The gauge "charge" is the electron spin, which is assumed to couple to the transverse acoustic phonons on the basis of spin ordering phenomena in [Formula: see text]- and [Formula: see text]-[Formula: see text], while the longitudinal mode is neutral. A generalization of the Peierls Mechanism is presented based on the discrete gauge invariance of crystals and the corresponding Ward-Takahashi identity.

Statistical properties of defect-dependent detachment strength in bioinspired dry adhesives.

Dry adhesives using surface microstructures inspired by climbing animals have been recognized for their potentially novel capabilities, with relevance to a range of applications including pick-and-place handling. Past work has suggested that performance may be strongly dependent on variability in the critical defect size among fibrillar sub-contacts. However, it has not been directly verified that the resulting adhesive strength distribution is well described by the statistical theory of fracture used.

Lymphatic Vessels Balance Viral Dissemination and Immune Activation following Cutaneous Viral Infection.

Lymphatic vessels lie at the interface between peripheral sites of pathogen entry, adaptive immunity, and the systemic host. Though the paradigm is that their open structure allows for passive flow of infectious particles from peripheral tissues to lymphoid organs, virus applied to skin by scarification does not spread to draining lymph nodes. Using cutaneous infection by scarification, we analyzed the effect of viral infection on lymphatic transport and evaluated its role at the host-pathogen interface.

Influence of Humidity on Grip and Release Adhesion Mechanisms for Gecko-Inspired Microfibrillar Surfaces.

Geckos have developed foot pads that allow them to maintain their unique climbing ability despite vast differences of surfaces and environments, from dry desert to humid rainforest. Likewise, successful gecko-inspired mimics should exhibit adhesive and frictional performance across a similarly diverse range of climates. In this work, we focus on the effect of relative humidity (RH) on the "frictional-adhesion" behavior of gecko-inspired adhesive pads.

Quantification of probe-sample interactions of a scanning thermal microscope using a nanofabricated calibration sample having programmable size.

We report a method for quantifying scanning thermal microscopy (SThM) probe-sample thermal interactions in air using a novel temperature calibration device. This new device has been designed, fabricated and characterised using SThM to provide an accurate and spatially variable temperature distribution that can be used as a temperature reference due to its unique design. The device was characterised by means of a microfabricated SThM probe operating in passive mode.

Correlating the Energetics and Atomic Motions of the Metal-Insulator Transition of M1 Vanadium Dioxide.

Materials that undergo reversible metal-insulator transitions are obvious candidates for new generations of devices. For such potential to be realised, the underlying microscopic mechanisms of such transitions must be fully determined. In this work we probe the correlation between the energy landscape and electronic structure of the metal-insulator transition of vanadium dioxide and the atomic motions occurring using first principles calculations and high resolution X-ray diffraction.

Cultural Adaptation of Interventions in Real Practice Settings.

This article provides an overview of some common challenges and opportunities related to cultural adaptation of behavioral interventions. Cultural adaptation is presented as a necessary action to ponder when considering the adoption of an evidence-based intervention with ethnic and other minority groups. It proposes a roadmap to choose existing interventions and a specific approach to evaluate prevention and treatment interventions for cultural relevancy.

Interactions of Anopheles gambiae odorant-binding proteins with a human-derived repellent: implications for the mode of action of n,n-diethyl-3-methylbenzamide (DEET).

The Anopheles gambiae mosquito, which is the vector for Plasmodium falciparum malaria, uses a series of olfactory cues emanating from human sweat to select humans as their source for a blood meal. Perception of these odors within the mosquito olfactory system involves the interplay of odorant-binding proteins (OBPs) and odorant receptors and disrupting the normal responses to those odorants that guide mosquito-human interactions represents an attractive approach to prevent the transmission of malaria. Previously, it has been shown that DEET targets multiple components of the olfactory system, including OBPs and odorant receptors.

1H, 13C and 15N NMR assignments of the C1A and C1B subdomains of PKC-delta.

The Protein Kinase C family of enzymes is a group of serine/threonine kinases that play central roles in cell-cycle regulation, development and cancer. A key step in the activation of PKC is translocation to membranes and binding of membrane-associated activators including diacylglycerol (DAG). Interaction of novel and conventional isotypes of PKC with DAG and phorbol esters occurs through the two C1 regulatory domains (C1A and C1B), which exhibit distinct ligand binding selectivity that likely controls enzyme activation by different co-activators.

Periodic mesoporous Li(x)(Mn(1/3)Ni(1/3)Co(1/3))O2 spinel.

A monoclinic periodic mesoporous Li(x)(Mn(1/3)Ni(1/3)Co(1/3))O(2) spinel has been successfully prepared for the first time using a 'two solvents' pore infiltration methodology on hard silica templates. More commonly used synthetic techniques are not applicable to this complex material. This important battery cathode has a surface area of over 180 m(2)g(-1) and a pore size of 5.

Production of VO2 M1 and M2 nanoparticles and composites and the influence of the substrate on the structural phase transition.

A two-step, high-purity, high-yield synthesis of nanoparticulate vanadium dioxide, which has a greater than 10-fold potential cost reduction is reported. This consists of a short reflux of V2O5 with aspartic acid, followed by calcination at 600 degrees C or above. The particles produced have a mean diameter of approximately 90 nm with phase change characteristics of transition temperature and enthalpy that compare favorably with a commercial standard.

Anisotropic structure deformation in the VO2 metal-insulator transition.

X-ray absorption fine structure data of tungsten (VI)-doped vanadium dioxide in the insulating phase, and during the metal-insulator transition, are presented for the first time. Tungsten L(III)- and vanadium K-edge data suggest that significant expansion in the [110] and [110] directions occurs across the phase transition from low to high temperature. This distortion breaks the bonds between Peierls-paired vanadium ions, opening a band gap, and reveals the nature of the mechanism by which tungsten doping lowers the transition temperature and enthalpy.

Diversifying the solid state and lyotropic phase behavior of nonionic urea-based surfactants.

The solid state and lyotropic phase behavior of 10 new nonionic urea-based surfactants has been characterized. The strong homo-urea interaction, which can prevent urea surfactants from forming lyotropic liquid crystalline phases, has been ameliorated through the use of isoprenoid hydrocarbon tails such as phytanyl (3,7,11,15-tetramethyl-hexadecyl) and hexahydrofarnesyl (3,7,11-trimethyl-dodecyl) or the oleyl chain (cis-octadec-9-enyl). Additionally, the urea head group was modified by attaching either a hydroxy alkyl (short chain alcohol) moiety to one of the nitrogens of the urea or by effectively "doubling" the urea head group by replacing it with a biuret head group.

Gold nanoparticle formation during bromoaurate reduction by amino acids.

The synthesis and characterization of water-soluble dispersions of gold nanoparticles by the reduction of a potassium tetrabromoaurate precursor solution using the amino acids L-tyrosine, glycyl-L-tyrosine, and L-arginine using alkaline synthesis conditions are reported. The particle sizes determined by small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM) measurements are found to be inversely proportional to the rate of particle formation, which was determined by time-resolved UV-visible spectrophotometry measurements, and vary very slowly at intermediate gold concentrations and rapidly at the extremes. Dispersions produced with a mixture of the two amino acids glycyl-L-tyrosine and L-tyrosine showed particle sizes and particle size distributions which were directly proportional to the ratio of the two L-amino acids, thus offering the possibility for control over the properties of the gold nanoparticle dispersions.