Toward Bottom-Up Understanding of Transport in Concentrated Battery Electrolytes.

Bottom-up understanding of transport describes how molecular changes alter species concentrations and electrolyte voltage drops in operating batteries. Such an understanding is essential to predictively design electrolytes for desired transport behavior. We herein advocate building a structure-property-performance relationship as a systematic approach to accurate bottom-up understanding.

Microcomputed tomography void analysis after cement cleanup methods.

Statement Of Problem: Cement at the restorative margin after implementation of the manufacturer's recommended procedure for cement cleanup has not been extensively evaluated.

Purpose: The purpose of this in vitro study was to use microcomputed tomography (μCT) to evaluate the number, volume, and width of voids left at the margin when dental cement is cleaned during the cementation process as per 2 manufacturer-prescribed methods for cement cleanup by evaluating a self-adhesive resin cement and a resin-modified glass ionomer cement.

Material And Methods: Twenty molar Ivorine Typodont prepared teeth were scanned, and lithium disilicate crowns were milled and cemented to the prepared teeth as per the manufacturer-recommended cementation process.

Pushing and Pulling: A Dual pH Trigger Controlled by Varying the Alkyl Tail Length in Heme Coordinating Peptide Amphiphiles.

Some organisms in nature that undergo anaerobic respiration utilize 1D nanoscale arrays of densely packed cytochromes containing the molecule heme. The assemblies can be mimicked with 1D nanoscale fibrils composed of peptide amphiphiles designed to coordinate heme in dense arrays. To create such materials and assemblies, it is critical to understand the assembly process and what controls the various aspects of hierarchical assembly.

Free energy calculations of the functional selectivity of 5-HT2B G protein-coupled receptor.

G Protein-Coupled Receptors (GPCRs) mediate intracellular signaling in response to extracellular ligand binding and are the target of one-third of approved drugs. Ligand binding modulates the GPCR molecular free energy landscape by preferentially stabilizing active or inactive conformations that dictate intracellular protein recruitment and downstream signaling. We perform enhanced sampling molecular dynamics simulations to recover the free energy surfaces of a thermostable mutant of the GPCR serotonin receptor 5-HT2B in the unliganded form and bound to a lysergic acid diethylamide (LSD) agonist and lisuride antagonist.

Sleep, fatigue and burnout among physicians: an American Academy of Sleep Medicine position statement.

Physician burnout is a serious and growing threat to the medical profession and may undermine efforts to maintain a sufficient physician workforce to care for the growing and aging patient population in the United States. Burnout involves a host of complex underlying associations and potential for risk. While prevalence is unknown, recent estimates of physician burnout are quite high, approaching 50% or more, with midcareer physicians at highest risk.

What is the role of sleep in physician burnout?

The occurrence of physician burnout is widespread among clinicians and academic faculty, who report indicators such as low quality of life and poor work-life balance. Chronic insufficient sleep, whether due to extended work hours, circadian misalignment, or unrecognized sleep disorders, is a critically important risk factor for burnout that is overlooked and under-studied, and interventions to promote healthy sleep may reduce burnout susceptibility among attending physicians. While strategies to reduce burnout among resident and attending physicians have been under-evaluated, evidence suggests a need to address burnout at both individual and organizational levels.

Effect of Chain Length Dispersity on the Mobility of Entangled Polymers.

While nearly all theoretical and computational studies of entangled polymer melts have focused on uniform samples, polymer synthesis routes always result in some dispersity, albeit narrow, of distribution of molecular weights (Đ_{M}=M_{w}/M_{n}∼1.02-1.04).

Polymers at Liquid/Vapor Interface.

Polymers confined to the liquid/vapor interface are studied using molecular dynamics simulations. We show that for polymers which are weakly immiscible with the solvent, the density profile perpendicular to the liquid/vapor interface is strongly asymmetric. On the vapor side of the interface, the density distribution falls off as a Gaussian with a decay length on the order of the bead diameter, whereas on the liquid side, the density profile decays as a simple exponential.

Coarse-Grained Modeling of Polyethylene Melts: Effect on Dynamics.

The distinctive viscoelastic behavior of polymers results from a coupled interplay of motion on multiple length and time scales. Capturing the broad time and length scales of polymer motion remains a challenge. Using polyethylene (PE) as a model macromolecule, we construct coarse-grained (CG) models of PE with three to six methyl groups per CG bead and probe two critical aspects of the technique: pressure corrections required after iterative Boltzmann inversion (IBI) to generate CG potentials that match the pressure of reference fully atomistic melt simulations and the transferability of CG potentials across temperatures.

A multi-chain polymer slip-spring model with fluctuating number of entanglements: Density fluctuations, confinement, and phase separation.

Coarse grained simulation approaches provide powerful tools for the prediction of the equilibrium properties of polymeric systems. Recent efforts have sought to develop coarse-graining strategies capable of predicting the non-equilibrium behavior of entangled polymeric materials. Slip-link and slip-spring models, in particular, have been shown to be capable of reproducing several key aspects of the linear response and rheology of polymer melts.

A multichain polymer slip-spring model with fluctuating number of entanglements for linear and nonlinear rheology.

A theoretically informed entangled polymer simulation approach is presented for description of the linear and non-linear rheology of entangled polymer melts. The approach relies on a many-chain representation and introduces the topological effects that arise from the non-crossability of molecules through effective fluctuating interactions, mediated by slip-springs, between neighboring pairs of macromolecules. The total number of slip-springs is not preserved but, instead, it is controlled through a chemical potential that determines the average molecular weight between entanglements.

Missing teeth and pediatric obstructive sleep apnea.

Background: Missing teeth in early childhood can result in abnormal facial morphology with narrow upper airway. The potential association between dental agenesis or early dental extractions and the presence of obstructive sleep apnea (OSA) was investigated.

Methods: We reviewed clinical data, results of polysomnographic sleep studies, and orthodontic imaging studies of children with dental agenesis (n = 32) or early extraction of permanent teeth (n = 11) seen during the past 5 years and compared their findings to those of age-, gender-, and body mass index-matched children with normal teeth development but tonsilloadenoid (T&A) hypertrophy and symptoms of OSA (n = 64).

Fully atomistic simulations of the response of silica nanoparticle coatings to alkane solvents.

Molecular dynamics simulations are used to study the effect of passivating ligands of varying lengths grafted to a nanoparticle and placed in various alkane solvents. Average height and density profiles for methyl-terminated alkoxylsilane ligands (-O-Si(OH)(2)(CH(2))(n)CH(3), with n = 9, 17, and 35) attached to a 5-nm-diameter amorphous silica nanoparticle with coverages of between 1.0 and 3.

Identifying viral integration sites using SeqMap 2.0.

Unlabelled: Retroviral integration has been implicated in several biomedical applications, including identification of cancer-associated genes and malignant transformation in gene therapy clinical trials. We introduce an efficient and scalable method for fast identification of viral vector integration sites from long read high-throughput sequencing. Individual sequence reads are masked to remove non-genomic sequence, aligned to the host genome and assembled into contiguous fragments used to pinpoint the position of integration.

In silico functional profiling of human disease-associated and polymorphic amino acid substitutions.

An important challenge in translational bioinformatics is to understand how genetic variation gives rise to molecular changes at the protein level that can precipitate both monogenic and complex disease. To this end, we compiled datasets of human disease-associated amino acid substitutions (AAS) in the contexts of inherited monogenic disease, complex disease, functional polymorphisms with no known disease association, and somatic mutations in cancer, and compared them with respect to predicted functional sites in proteins. Using the sequence homology-based tool SIFT to estimate the proportion of deleterious AAS in each dataset, only complex disease AAS were found to be indistinguishable from neutral polymorphic AAS.

Evaluation of features for catalytic residue prediction in novel folds.

Structural genomics projects are determining the three-dimensional structure of proteins without full characterization of their function. A critical part of the annotation process involves appropriate knowledge representation and prediction of functionally important residue environments. We have developed a method to extract features from sequence, sequence alignments, three-dimensional structure, and structural environment conservation, and used support vector machines to annotate homologous and nonhomologous residue positions based on a specific training set of residue functions.

Identification of similar regions of protein structures using integrated sequence and structure analysis tools.

Background: Understanding protein function from its structure is a challenging problem. Sequence based approaches for finding homology have broad use for annotation of both structure and function. 3D structural information of protein domains and their interactions provide a complementary view to structure function relationships to sequence information.

Individual differences in the consideration of future consequences scale correlate with sleep habits, sleep quality, and GPA in university students.

The present study examined relationships between individual differences in the consideration of future consequences, sleep habits and sleep quality, and academic achievement in a sample of 231 undergraduates, 156 women and 75 men, whose ages ranged from 18 to 41 years (M = 19.0 yr., SD=2.