Fracton order describes novel quantum phases of matter that host quasiparticles with restricted mobility and, thus, lies beyond the existing paradigm of topological order. In particular, excitations that cannot move without creating multiple excitations are called fractons. Here, we address a fundamental open question-can the notion of self-exchange statistics be naturally defined for fractons, given their complete immobility as isolated excitations? Surprisingly, we demonstrate how fractons can be exchanged and show that their self-statistics is a key part of the characterization of fracton orders.
View Article and Find Full Text PDFACS Appl Mater Interfaces
May 2021
Background: The prevalence of childhood obesity is higher in economically and socially deprived areas. Higher levels of physical activity reduce the risk of excessive weight gain in youth, and research has focused on environmental factors associated with children's physical activity, though the term "physical activity desert" has not come into wide use.
Methods: This exploratory study operationalized the term "physical activity desert" and tested the hypothesis that children living in physical activity deserts would be less physically active than children who do not.
ACS Appl Mater Interfaces
July 2020
Two-dimensional urea- and thiourea-containing covalent organic frameworks (COFs) were synthesized at ambient conditions at large scale within 1 h in the absence of an acid catalyst. The site-isolated urea and thiourea in the COF showed enhanced catalytic efficiency as a hydrogen-bond-donating organocatalyst compared to the molecular counterparts in epoxide ring-opening reaction, aldehyde acetalization, and Friedel-Crafts reaction. The COF catalysts also had excellent recyclability.
View Article and Find Full Text PDFThe acid-base dissociation constant, p, is a key parameter to define the ionization state of a compound and directly affects its biopharmaceutical profile. In this study, we developed a novel approach for p prediction using rooted topological torsion fingerprints in combination with five machine learning (ML) methods: random forest, partial least squares, extreme gradient boosting, lasso regression, and support vector regression. With a large and diverse set of 14 499 experimental p values, p models were developed for aliphatic amines.
View Article and Find Full Text PDFWe study the ground state phases of a rotating two-component, or binary, Bose-Einstein condensate, wherein one component possesses a large permanent magnetic dipole moment. A variety of nontrivial phases emerge in this system, including a half-quantum vortex (HQV) chain phase and a HQV molecule phase, where HQVs bind at short distances. We attribute these phases to the development of a minimum in the HQV interaction potential, which emerges without coherent coupling or attractive interactions between the components.
View Article and Find Full Text PDFJAMA Otolaryngol Head Neck Surg
January 2013
Arch Otolaryngol Head Neck Surg
December 2011
Objective: To test the perception that post-tympanostomy tube otorrhea caused by methicillin-resistant Staphylococcus aureus (MRSA) is a more virulent disease than otorrhea caused by other pathogens by analyzing the clinical differences and disease courses in children diagnosed with otorrhea caused by MRSA bacteria vs non-MRSA bacteria.
Design: Retrospective review.
Setting: Tertiary children's hospital.
This paper describes the application of de novo design utilizing exclusively ligand information. In the current approach, ligand design criteria, including pharmacophores, similarity and desired properties are applied as part of a fitness function driving the design process, instead of using them as filters after the process. This allows relevant parts of chemical space to be explored more efficiently.
View Article and Find Full Text PDFNatural peptide agonists of corticotrophin-releasing factor (CRF) receptors bind to the receptor by a two-site mechanism as follows: the carboxyl end of the ligand binds the N-terminal extracellular domain (ECD) of the receptor and the amino portion of the ligand binds the extracellular face of the seven transmembrane region. Recently, peptide antagonists homologous to the 12 C-terminal residues of CRF have been derived, which bind the CRF(1) receptor through an interaction with the ECD. Here we characterized the binding of a minimal 12-residue peptide antagonist while bound to the isolated ECD of the CRF(1) receptor.
View Article and Find Full Text PDFA new consensus approach has been developed for ligand-based virtual screening. It involves combining highly disparate properties in order to improve performance in virtual screening. The properties include structural, 2D pharmacophore and property-based fingerprints, scores derived using BCUT descriptors, and 3D pharmacophore approaches.
View Article and Find Full Text PDFVarious (arene)tricarbonylchromium complexes were synthesized within the confines of NaX zeolite and studied with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and carbon-13 magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy. In each case, the surface complex Cr(CO)3(Oz)3 (Oz represents a framework oxygen of the NaX zeolite) was prepared before a particular arene was added. The arenes benzene, toluene, mesitylene, anisole, and aniline all produce hexahapto pi-complexes physisorbed within the zeolite supercage.
View Article and Find Full Text PDFInt J Pediatr Otorhinolaryngol
January 2003
Producing quality clinical candidates less prone to late stage failure is greatly facilitated by better integration of the relevant high throughput functions and the inclusion of ADME/toxicology further upstream in the discovery process. We describe the tasks and their integration in the context of the design, make and test triad.
View Article and Find Full Text PDFWe describe statistical techniques for effective evaluation of large virtual combinatorial libraries (> 10(10) potential compounds). The methods described are used for computationally evaluating templates (prioritization of candidate libraries for synthesis and screening) and for the design of individual combinatorial libraries (e.g.
View Article and Find Full Text PDFWe have performed all atom simulations of blocked peptides of the form (AAXAA)3, where X = Gln, Asn, Glu, Asp, Arg, and Lys with explicit water molecules to examine the interactions between side chains spaced i,i-5 in the sequence. Although side chains in this i,i-5 arrangement are commonly believed to be noninteracting, we have observed the formation of unusual i,i-5 main chain hydrogen bonding in such sequences with positively charged residues (Lys) as well as polar uncharged groups (Gln). Our results are consistent with the unusual percentage of hydrogen bonding curves produced by amide exchange measurements on the well-studied sequence acetyl-(AAQAA)3-amide in water (Shalongo, W.
View Article and Find Full Text PDFJ Am Dent Assoc
December 1985
There are considerable demographic data that can be used in an organized manner to give dentists and graduating dental students greater insight relative to locating dental practices. This article further explores the concept and emphasizes the methods that can be used to measure and compare qualitatively the suitability of communities (service areas) and specific sites as practice locations. In addition, a method is reported that enables the user to ascertain the representativeness of a service area in terms of the demographic factors that affect the demand for dental services.
View Article and Find Full Text PDFA realistic approach to locating a dental practice involves the consideration of factors affecting the demand for dental services in an area. This dictates examination of the demographic and economic determinants of demand. Many retail businesses have used this approach to making locational decisions, and dentistry should benefit from this same process.
View Article and Find Full Text PDFNuclear magnetic resonance (NMR) measurements provide both structural and dynamical information about the molecules in which nuclear resonances are observed. This manuscript addresses NMR relaxation of water protons in protein powder systems. Inclusion of magnetic communication between the water proton spins and protein proton spins leads to a clearer view of water molecule dynamics at the protein surface than has been previously available.
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