Publications by authors named "Sokoloff J"

Unlabelled: Intestinal microbes, whether resident or transient, influence the physiology of their hosts, altering both the chemical and the physical characteristics of the gut. An example of the latter is the human pathogen ability to induce strong mechanical contractions, discovered in zebrafish. The underlying mechanism has remained unknown, but the phenomenon requires the actin crosslinking domain (ACD) of 's type VI secretion system (T6SS), a multicomponent protein syringe that pierces adjacent cells and delivers toxins.

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Dogs' comprehension of human gestures has been characterized as more human-like than that of our closest primate relatives, due to a level of flexibility and spontaneous performance on par with that of human infants. However, many of the critical experiments that have been the core evidence for an understanding of human communicative intentions in dogs have yet to be replicated. Here we test the ability of dogs to comprehend a pointing gesture while varying the salience of the gesture and the context in which it is made.

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In this Letter, we present a simple mechanism that explains the recent experimental observation of the breakdown of the Nernst-Einstein (NE) relation for an ion moving in a carbon nanotube of subnanometer diameter. We argue that the friction acting on the ion is largely independent of the ion velocity, i.e.

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Postoperative pain is a major clinical problem imposing a significant burden on patients and society. In a survey 2 years after orthopedic surgery, 57% of patients reported persisting postoperative pain. However, only limited progress has been made in the development of safe and effective therapies to prevent the onset and chronification of pain after orthopedic surgery.

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A simple model for the friction experienced by the one-dimensional water chains that flow through subnanometer diameter carbon nanotubes is studied. The model is based on a lowest order perturbation theory treatment of the friction experienced by the water chains due to the excitation of phonon and electron excitations in both the nanotube and the water chain, as a result of the motion of the chain. On the basis of this model, we are able to demonstrate how the observed flow velocities of water chains through carbon nanotubes of the order of several centimeters per second can be accounted for.

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Postoperative pain is a major clinical problem imposing a significant burden on our patients and society. Up to 57% of patients experience persistent postoperative pain 2 years after orthopedic surgery [49]. Although many studies have contributed to the neurobiological foundation of surgery-induced pain sensitization, we still lack safe and effective therapies to prevent the onset of persistent postoperative pain.

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Electrical image potentials can be important in small spaces, such as nanoscale pores in porous electrodes, which are used in capacitive desalination and in supercapacitors, as argued by Bazant's group at Massachusetts Institute of Technology. It will be shown here that inside pores in porous metallic materials the image potentials can be considerably larger than near flat walls, as a result of the fact that the dielectric constant for an electric field perpendicular to a wall is much smaller than the bulk dielectric constant of water. Calculations will be presented for the image potential in spherical and cylindrically shaped pores.

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Electrical image potentials near a metallic or a dielectric wall of higher dielectric constant than that of the solution are attractive, and therefore, could concentrate salt ions near the wall. In fact, ions in room temperature ionic liquids have been observed to precipitate near a metallic surface (but not near a nonmetallic surface). It will be argued that a likely reason for why precipitation of ions in salt water due to electrical image forces has not as yet been observed is that the solvation of the ions is reduced near the wall.

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We conducted a systematic investigation of droplet evaporation on different surfaces. We found that droplets formed even with distilled water do not disappear with evaporation but instead shrink to a residue of a few micrometers lasting over 24 h. The residue formation process differs across surfaces and humidity levels.

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Effects of electrical image potentials on the salt ion concentration near a solid wall are studied using a one-loop approximation treatment of the grand canonical partition function, which is the Debye-Hückel approximation. Electrical image potentials resulting from both metallic and dielectric walls of dielectric constant larger than that of water near the wall are considered. Our treatment of this problem supports the conclusions of an earlier publication by one of the authors which shows that near a solid wall there should be a high concentration of ions, resulting from image potentials.

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It will be shown that for a solution of salt dissolved in water in contact with a metallic or dielectric wall, the concentration of salt ions (both positive and negative) near the wall can be large enough to exceed the salt's solubility limit, as a result of electrical image charge forces. In addition, since the dielectric constant of water increases from 2.1 at the wall to 81 at about 1 nm from a solid wall, there will be an attractive image potential near the plane on which this increase of the dielectric constant occurs.

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A mechanism for removal of salt from salt water is discussed, which results from friction due to Ohm's law heating, resulting from motion of an electron charge induced in the tube walls by the water molecules' dipoles and the ions' charges. The desalination occurs because this friction is larger for salt ions than for water molecules. Friction due to Ohm's law heating might also provide an explanation for the observation by Secchi et al.

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It is argued that Voronoi tessellation theory can be used to model the observed diffusion of microgel particles in a highly compressed microgel colloid. It is shown that this model is able to account for the fact that even when the microgel colloid is highly compressed, the particles can diffuse, while the diffusion rate decreases as the degree of compression of the microgel colloid increases, as observed.

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Secchi et al. [Nature (London) 537, 210 (2016)10.1038/nature19315] observed a large enhancement of the permeability and slip length in carbon nanotubes when the tube radius is of the order of 15 nm, but not in boron nitride nanotubes.

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A theoretical treatment is provided for effects of capillary forces on a hemispherically shaped hydrogel sample pressed against a solid hydrophilic surface. It is pointed out that the adhesion of a hydrogel to a surface resulting from capillary forces is different from that of a nonporous solid because of the porous nature of the hydrogel. Because of this, the Laplace pressure subtracts from the osmotic pressure inside the gel.

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The compression of polyelectrolyte microgel particles in a salt-free highly compressed colloid due to osmotic pressure outside of the particles due to counterions located there is studied for a model based on a quasi-analytic solution of the Poisson-Boltzmann equation and a model for the gel elasticity based on counterion osmotic pressure inside the particles and polymer elasticity (of entropic origin). It is found that for particles of radius of the order of a tenth of a micron, the counterion osmotic pressure should play a significant role in the compression of the particles, especially particles which do not have a corona (i.e.

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One role of a lubricant is to prevent wear of two surfaces in contact, which is likely to be the result of adhesive forces that cause a pair of asperities belonging to two surfaces in contact to stick together. Such adhesive sticking of asperities can occur both for sliding surfaces and for surfaces which are pressed together and then pulled apart. The latter situation, for example, is important for contact lenses, as prevention of sticking reduces possible damage to the cornea as the lenses are inserted and removed from the eye.

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Evidence suggests over-representation of autism spectrum disorders (ASDs) and behavioral difficulties among people referred for gender issues, but rates of the wish to be the other gender (gender variance) among different neurodevelopmental disorders are unknown. This chart review study explored rates of gender variance as reported by parents on the Child Behavior Checklist (CBCL) in children with different neurodevelopmental disorders: ASD (N = 147, 24 females and 123 males), attention deficit hyperactivity disorder (ADHD; N = 126, 38 females and 88 males), or a medical neurodevelopmental disorder (N = 116, 57 females and 59 males), were compared with two non-referred groups [control sample (N = 165, 61 females and 104 males) and non-referred participants in the CBCL standardization sample (N = 1,605, 754 females and 851 males)]. Significantly greater proportions of participants with ASD (5.

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Background: Unstuck and On Target (UOT) is an executive function (EF) intervention for children with autism spectrum disorders (ASD) targeting insistence on sameness, flexibility, goal-setting, and planning through a cognitive-behavioral program of self-regulatory scripts, guided/faded practice, and visual/verbal cueing. UOT is contextually-based because it is implemented in school and at home, the contexts in which a child uses EF skills.

Methods: To evaluate the effectiveness of UOT compared with a social skills intervention (SS), 3rd-5th graders with ASD (mean IQ = 108; UOT n = 47; SS n = 20) received interventions delivered by school staff in small group sessions.

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The interaction between two grafted polymer gels was investigated. We studied a defect-free network of diamond-like topology containing 8 tetra-functional nodes linked by 16 non-crossing chains. In order to explain the very low friction coefficient observed for polyelectrolyte hydrogels, we computed the monomer density profile of these polymer gels, the interpenetration between two polymer gels (defined as the percentage of monomers belonging to one gel which have penetrated the second gel), the normal force per unit area, and the radial distribution function of the interacting monomers.

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A Poisson-Boltzmann equation solution is used to determine the thickness of a thin fluid lubricating layer predicted to separate two polyelectrolyte hydrogels in contact for arbitrary salt concentration as a function of applied load and fixed charge and salt concentration. We consider loads ranging from 1 Pa, at which the thin fluid layer thickness is of the order of micron, up to loads of the order of a MPa, at which it is estimated to be of the order of an angstrom. This allows us to predict the thickness of this layer over the wide range of loads that can occur in various applications of hydrogels.

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Background: The attentional blink (AB) phenomenon was used to assess the effect of emotional information on early visual attention in typically developing (TD) children and children with autism spectrum disorders (ASD). The AB effect is the momentary perceptual unawareness that follows target identification in a rapid serial visual processing stream. It is abolished or reduced for emotional stimuli, indicating that emotional information has privileged access to early visual attention processes.

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Age-related changes in social attribution skills were assessed using the "Triangles Playing Tricks" task in 7-17 year old high functioning children with ASDs (n=41) and in typically developing (TD) children (n=58) matched on age, IQ, and sex ratio. Children with ASDs gave responses that received lower intentionality and appropriateness ratings than did TD children in both the goal-directed and theory of mind (ToM) conditions. Results remained unchanged when the effects of verbal output (i.

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Surface roughness and dry friction.

Phys Rev E Stat Nonlin Soft Matter Phys

February 2012

Persson's multiscale contact mechanics theory combined with a multiscale Brillouin-Prandtl-Tomlinson model is used to show that on the basis of these models "dry friction" [i.e., kinetic friction that remains at exceedingly small velocities (but still above the creep range) close to its value at higher velocities] should almost always occur for self-affine surfaces when the dominant interaction between two surfaces in contact is due to interatomic hard core repulsion, except for extremely smooth surfaces (i.

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Background And Objectives: Neuropsychological impairment among patients with substance use disorders (SUDs) contributes to poorer treatment processes and outcomes. However, neuropsychological assessment is typically not an aspect of patient evaluation in SUD treatment programs because it is prohibitively time and resource consuming. In a previous study, we examined the concurrent validity, classification accuracy, and clinical utility of a brief screening measure, the Montreal Cognitive Assessment (MoCA), in identifying cognitive impairment among SUD patients.

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