Multiscale dynamical symmetries and selection rules in nonlinear optics.

Symmetries and their associated selection rules are extremely useful in many fields of science. For systems of electromagnetic (EM) fields interacting with matter, the symmetries of matter and the EM fields' time-dependent polarization determine the properties of the nonlinear responses, and they can be facilitated for controlling light emission and enabling ultrafast symmetry breaking spectroscopy of various properties. Here, we formulate a general theory that describes the macroscopic and microscopic dynamical symmetries (including quasicrystal-like symmetries) of EM vector fields, revealing many previously unidentified symmetries and selection rules in light-matter interactions.

Topological Order in an Antiferromagnetic Tetratic Phase.

We study lattice melting in two-dimensional systems of spinful particles that interact antiferromagnetically. We argue that, for strong spin interactions, single lattice dislocations are forbidden by magnetic frustration. This leads to a melting scenario in which a tetratic phase, containing free dislocation pairs and bound disclinations, separates the solid from the liquid.

Resonantly enhanced polariton wave mixing and parametric instability in a Floquet medium.

We introduce a new theoretical approach for analyzing pump and probe experiments in non-linear systems of optical phonons. In our approach, the effect of coherently pumped polaritons is modeled as providing time-periodic modulation of the system parameters. Within this framework, propagation of the probe pulse is described by the Floquet version of Maxwell's equations and leads to phenomena such as frequency mixing and resonant parametric production of polariton pairs.

Floquet group theory and its application to selection rules in harmonic generation.

Symmetry is one of the most generic and useful concepts in science, often leading to conservation laws and selection rules. Here we formulate a general group theory for dynamical symmetries (DSs) in time-periodic Floquet systems, and derive their correspondence to observable selection rules. We apply the theory to harmonic generation, deriving closed-form tables linking DSs of the driving laser and medium (gas, liquid, or solid) in (2+1)D and (3+1)D geometries to the allowed and forbidden harmonic orders and their polarizations.

SHANK3 Regulates Intestinal Barrier Function Through Modulating ZO-1 Expression Through the PKCε-dependent Pathway.

Background: The integrity of the gut barrier in patients with inflammatory bowel disease is known to be impaired but the exact mechanisms remain mostly unknown. SHANK3 mutations are associated with autism, and patients with autism are known to have higher proportions of inflammatory bowel disease. Here, we explore the role of SHANK3 in inflammatory bowel disease, both in vivo and in vitro.

Dynamical Response near Quantum Critical Points.

We study high-frequency response functions, notably the optical conductivity, in the vicinity of quantum critical points (QCPs) by allowing for both detuning from the critical coupling and finite temperature. We consider general dimensions and dynamical exponents. This leads to a unified understanding of sum rules.

Collective Modes in a Quantum Solid.

We provide a theoretical explanation for the optical modes observed in inelastic neutron scattering on the bcc solid phase of helium 4 [T. Markovich et al., Phys.

Gastroenterology, Academic Medicine and a Changing Landscape.

The forces that are reshaping the delivery of health care through much of the developed world are especially acute within academic centers that carry the responsibility for delivering that care while advancing medical knowledge and ensuring well-trained physicians. Gastroenterology will not be spared any of those forces, and in some ways represents the leading edge of their impact. Though the dynamics vary within the context of the health-care delivery and scientific enterprise of individual countries, common elements are demands for greater accountability and transparency in how academic medical centers demonstrate their value while assuring broad access to their expertise.

Public reporting of patient safety metrics: ready or not?

In its 1999 report, the Institute of Medicine estimated that medical error leads to between 44,000 and 98,000 deaths per year. Given that statistic, public reporting of quality and safety metrics is a welcome response that may serve to reduce the rate of adverse events and restore patients' trust in the health care system. To ensure that any public reporting system fulfills its potential, several questions must be addressed: Are we measuring the right metrics? Are the metrics accurate, valid, and is their public reporting effecting change? Based on a review of the literature, it is clear that current metrics suffer from low reliability, low validity, and possibly minimal relevance to the intended consumer.

SLCO3A1, A novel crohn's disease-associated gene, regulates nf-κB activity and associates with intestinal perforation.

Background & Aims: To date, only one gene (TNFSF15) has been identified and validated as a Crohn's disease (CD)-associated gene in non-Caucasian populations. This study was designed to identify novel CD-associated single nucleotide polymorphisms (SNPs)/genes and to validate candidate genes using a functional assay.

Methods: SNPs from 16 CD patients and 16 age- and sex-matched control patients were analyzed using Illumina platform analysis.

Gastroenterology's editors-in-chief: historical and personal perspectives of their editorships.

Fourteen editors-in-chiefs have steered Gastroenterologyto success since its inception in 1943. Five (Alvarez, Ivy, Aaron, Grossman, and Donaldson) are no longer with us. Their personalities and editorships, along with those of Marvin Sleisenger, are presented by their admirers.

Loss of TLR2 worsens spontaneous colitis in MDR1A deficiency through commensally induced pyroptosis.

Variants of the multidrug resistance gene (MDR1/ABCB1) have been associated with increased susceptibility to severe ulcerative colitis (UC). In this study, we investigated the role of TLR/IL-1R signaling pathways including the common adaptor MyD88 in the pathogenesis of chronic colonic inflammation in MDR1A deficiency. Double- or triple-null mice lacking TLR2, MD-2, MyD88, and MDR1A were generated in the FVB/N background.

Photonic Floquet topological insulators.

Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on their surfaces. In two dimensions, electrons on the surface of a topological insulator are not scattered despite defects and disorder, providing robustness akin to that of superconductors. Topological insulators are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics.

Fate of the Higgs mode near quantum criticality.

We study a relativistic O(N) model near the quantum critical point in 2 + 1 dimensions for N = 2 and N = 3. The scalar susceptibility is evaluated by Monte Carlo simulation. We show that the spectrum contains a well-defined peak associated with the Higgs mode arbitrarily close to the critical point.

Increased T-helper 2 cytokines in bile from patients with IgG4-related cholangitis disrupt the tight junction-associated biliary epithelial cell barrier.

Background & Aims: IgG4-related cholangitis is a chronic inflammatory biliary disease that involves different parts of the pancreatobiliary system, but little is known about its mechanisms of pathogenesis. A T-helper (Th) 2 cell cytokine profile predominates in liver tissues from these patients. We investigated whether Th2 cytokines disrupt the barrier function of biliary epithelial cells (BECs) in patients with IgG4-related cholangitis.

Modulated Floquet topological insulators.

The application of spatially uniform light on conventional insulators can induce Floquet spectra with characteristics akin to those of topological insulators. We demonstrate that spatial modulation of light allows for remarkable control of the properties in these systems. We provide configurations to generate one-dimensional bulk modes, photoinduced currents, as well as fractionalized excitations.

Tribbles 2 (Trib2) is a novel regulator of toll-like receptor 5 signaling.

Background: Toll-like receptors (TLRs) are expressed by a variety of cells, including intestinal epithelia. However, the full spectrum of regulators modulating innate responses via TLRs has not been delineated. Tribbles (Trib) have been identified as a highly conserved family of kinase-like proteins.

Enhanced innate immune responsiveness and intolerance to intestinal endotoxins in human biliary epithelial cells contributes to chronic cholangitis.

Background: Pattern recognition receptors (PRRs) orchestrate the innate immune defence in human biliary epithelial cells (BECs). Tight control of PRR signalling provides tolerance to physiological amounts of intestinal endotoxins in human bile to avoid constant innate immune activation in BECs.

Aims: We wanted to determine whether inappropriate innate immune responses to intestinal endotoxins contribute to the development and perpetuation of chronic biliary inflammation.

Toll-like receptor 4 variant D299G induces features of neoplastic progression in Caco-2 intestinal cells and is associated with advanced human colon cancer.

Background & Aims: The Toll-like receptor (TLR) 4 mediates homeostasis of the intestinal epithelial cell (IEC) barrier. We investigated the effects of TLR4-D299G on IEC functions.

Methods: We engineered IECs (Caco-2) to stably overexpress hemagglutinin-tagged wild-type TLR4, TLR4-D299G, or TLR4-T399I.