Directed emission of CdSe nanoplatelets originating from strongly anisotropic 2D electronic structure

ntrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k-space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters

Use of Rome II criteria in childhood defecation disorders: Applicability in clinical and research practice

Objectives To evaluate the prevalence of pediatric functional gastrointestinal disorders with the use of the Rome II criteria and to compare these data with the classic Iowa criteria. Study design Patients recorded defecation and encopresis frequency. A standard history was taken and a physical examination including a rectal examination was done. The prevalence of both criteria was assessed and compared. Results One hundred ninety-eight consecutive patients (age, 0.66 to 15.76 years; 131 male subjects) were included. According to the Rome II criteria, 64%, 18%. and 21% of patients fulfilled the criteria for functional constipation, functional fecal retention, and functional nonretentive fecal soiling, respectively. Using the classic criteria, 74% and 18% of patients fulfilled the criteria for pediatric constipation and solitary encopresis, respectively; 16% of the patients fulfilling the pediatric constipation criteria were not recognized by the Rome II constipation criteria. Fair agreement was found between functional nonretentive fecal soiling and solitary encopresis. Encopresis was present in 79% of constipated children. Conclusions The Rome criteria are restrictive and exclude several children with constipation. We recommend including encopresis and rectal digital examination and excluding arbitrary age limits and retentive behavior in the revision of the Rome criteri

Cystic fibrosis and the role of gastrointestinal outcome measures in the new era of therapeutic CFTR modulation

With the development of new drugs that directly affect CFTR protein function, clinical trials are being designed or initiated for a growing number of patients with cystic fibrosis. The currently available and accepted clinical endpoints, FEV1 and BMI, have limitations. The aim of this report is to draw attention to the need and the ample possibilities for the development and validation of relevant gastrointestinal clinical endpoints for scientific evaluation of CFTR modulation treatment, particularly in young children and infants. The gastrointestinal tract offers very good opportunities to measure CFTR protein function and systematically evaluate CF related clinical outcomes based on the principal clinical gastrointestinal manifestations of CF: intestinal pH, intestinal transit time, intestinal bile salt malabsorption, intestinal inflammation, exocrine pancreatic function and intestinal fat malabsorption. We present a descriptive analysis of a variety of gastrointestinal outcome measures for clinical relevance, reliability, validity, responsiveness to interventions, feasibility in particular in young children and the availability of reference values. (C) 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved

Treatment of inflammatory bowel disease in childhood: Best available evidence

The physician treating children with inflammatory bowel disease is confronted with a number of specific problems, one of them being the lack of randomized, controlled drug trials in children. In this review, the role of nutritional therapy is discussed with a focus on primary treatment, especially for children with Crohn's disease. Then, the available medical therapies are highlighted, reviewing the evidence of effectiveness and side effects in children, as compared with what is known in adults. Nutritional therapy has proven to be effective in inducing and maintaining remission in Crohn's disease while promoting linear growth. Conventional treatment consists of aminosalicylates and corticosteroids, whereas the early introduction of immunosuppressives (such as azathioprine or 6-mercaptopurine) is advocated as maintenance treatment. If these drug., are not tolerated or are ineffective, methotrexate may serve as an alternative in Crohn's disease. Cyclosporine is an effective rescue therapy in severe ulcerative colitis, but only will postpone surgery. A novel strategy to treat Crohn's disease is offered by infliximab, a monoclonal antibody to the proinflammatory cytokine tumor necrosis factor (TNF)-alpha. Based on the best-available evidence, suggested usage is provided for separate drugs with respect to dosage and monitoring of side effects in childre