Bound States and Supercriticality in Graphene-Based Topological Insulators

We study the bound state spectrum and the conditions for entering a supercritical regime in graphene with strong intrinsic and Rashba spin-orbit interactions within the topological insulator phase. Explicit results are provided for a disk-shaped potential well and for the Coulomb center problem

Oral Food Challenge Failures Among Foods Restricted Due to Atopic Dermatitis

BACKGROUND Recent studies have suggested that removing foods from the diet to manage atopic dermatitis (AD), based on positive allergy tests, may lead to immediate allergic reactions on reintroduction of that food. OBJECTIVE The purpose of this study was to examine the frequency of oral food challenge (OFC) failures among foods removed from the diet as suspected AD triggers, focusing on the five major food allergens in the US. METHODS OFCs to egg, milk, peanut, soy, and wheat, performed from 2008-14, at a children's hospital's allergy clinics, were reviewed. OFCs were offered based on history and laboratory values. Reasons for food avoidance were classified as food allergy (IgE-mediated reaction occurring within two hours); sensitization only (lack of introduction due to positive test results); and removal due to test results during AD evaluation. RESULTS There were 442 OFCs performed, with 89 failures (20.1%). Reasons for OFCs included a history of food allergy (320/442; 72.4%); food sensitization without any introduction (77/442; 17.4%); and AD (45/442; 10.2%). OFC failures among those who had food allergy (70/320; 21.9%); sensitization only (13/77; 16.9%); and suspected AD trigger (6/45; 13.3%) did not significantly differ (p=0.63). Wheat was more likely to be avoided than the other four foods for AD concerns (p<0.0001). CONCLUSION The frequency of OFC failure among those who removed foods suspected as AD triggers was 13.3%, indicating a loss of tolerance. Restriction of foods to manage AD must be done with caution and close monitoring

Role of the Microbiome in Allergic Disease Development

PURPOSE OF REVIEW: Evidence suggests that the microbiome of the skin, gastrointestinal tract, and airway contribute to health and disease. As we learn more about the role that the microbiota plays in allergic disease development, we can develop therapeutics to alter this pathway. RECENT FINDINGS: Epidemiologic studies reveal that an association exists between environmental exposures, which alter the microbiota, and developing atopic dermatitis, food allergy, and/or asthma. In fact, samples from the skin, gastrointestinal tract, and respiratory tract reveal distinct microbiotas compared with healthy controls, with microbial changes (dysbiosis) often preceding the development of allergic disease. Mechanistic studies have confirmed that microbes can either promote skin, gut, and airway health by strengthening barrier integrity, or they can alter skin integrity and damage gut and airway epithelium. In this review, we will discuss recent studies that reveal the link between the microbiota and immune development, and we will discuss ways to influence these changes

Detection of Pathogenic Bacteria During Rhinovirus Infection is Associated with Increased Respiratory Symptoms and Exacerbations of Asthma

Background Detection of either viral or bacterial pathogens is associated with wheezing in children, however the influence of both bacteria and virus on illness symptoms has not been described. Objective We evaluated bacterial detection during peak RV season in children with and without asthma to determine if an association exists between bacterial infection and the severity of RV illnesses. Methods 308 children (166 with asthma, 142 without asthma) ages 4–12 years provided five consecutive weekly nasal samples during September, and scored cold and asthma symptoms daily. Viral diagnostics and quantitative PCR for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were performed on all nasal samples. Results Detection rates were 53%, 17% and 11% for H. influenzae, S. pneumoniae and M. catarrhalis, respectively, with detection of RV increasing the risk of detecting bacteria within the same sample (OR 2.0, 95% CI 1.4–2.7, p<0.0001) or the following week (OR 1.6 (1.1–2.4), p=0.02). In the absence of RV, S. pneumoniae was associated with increased cold symptoms (mean 2.7 (95% CI 2.0–3.5) vs. 1.8 (1.5–2.2), p=0.006) and moderate asthma exacerbations (18% (12%–27%) vs. 9.2% (6.7%–12%), p=0.006). In the presence of RV, S. pneumoniae was associated with increased moderate asthma exacerbations (22% (16%–29%) vs. 15% (11%–20%), p=0.01). Furthermore, M. catarrhalis detected alongside RV increased the likelihood of experiencing cold and/or asthma symptoms compared to isolated detection of RV (OR 2.0 (1.0–4.1), p=0.04). Regardless of RV status, H. influenzae was not associated with respiratory symptoms. Conclusion RV infection enhances detection of specific bacterial pathogens in children with and without asthma. Furthermore, these findings suggest that M. catarrhalis and S. pneumoniae contribute to the severity of respiratory illnesses, including exacerbations of asthma

Geminate recombination dynamics studied via electron reexcitation: Kinetic analysis for anion CTTS photosystems

Recently, it became practicable to study geminate recombination dynamics of solvated electrons in polar liquids by using short pulses of light to reexcite these electrons back into the conduction band of the liquid and observe a change in the fraction of electrons that escape geminate recombination. In this Letter, the potential of this technique to provide additional insight into the recombination dynamics of electrons generated by charge-transfer-to-solvent (CTTS) photodetachment from monovalent anions in polar liquids is studied theoretically. The resulting expression accounts for the recent results from B.J. Schwartz's group at UCLA for electron photodetachment from Na- in tetrahydrofuran.Comment: 12 pages, 1 figure; to be submitted to Chem. Phys. Let

Recombination of Geminate (OH,eaq-) Pairs in Concentrated Alkaline Solutions: Lack of Evidence For Hydroxyl Radical Deprotonation

Picosecond dynamics of hydrated electrons and hydroxyl radicals generated in 200 nm photodissociation of aqueous hydroxide and 400 nm (3-photon) ionization of water in concentrated alkaline solutions were obtained. No deprotonation of hydroxyl radicals was observed on sub-nanosecond time scale, even in 1-10 M KOH solutions. This result is completely at odds with the kinetic data for deprotonation of OH radical in dilute alkaline solutions. We suggest that the deprotonation of hydroxyl radical is slowed down dramatically in concentrated alkaline solutions.Comment: 12 pages; 2 figures; submitted to Chem. Phys. Let

Increased Sleep Fragmentation Leads to Impaired Off-Line Consolidation of Motor Memories in Humans

A growing literature supports a role for sleep after training in long-term memory consolidation and enhancement. Consequently, interrupted sleep should result in cognitive deficits. Recent evidence from an animal study indeed showed that optimal memory consolidation during sleep requires a certain amount of uninterrupted sleep