Convergent Perturbation Theory for a q-deformed Anharmonic Oscillator

A $q$--deformed anharmonic oscillator is defined within the framework of $q$--deformed quantum mechanics. It is shown that the Rayleigh--Schr\"odinger perturbation series for the bounded spectrum converges to exact eigenstates and eigenvalues, for $q$ close to 1. The radius of convergence becomes zero in the undeformed limit.Comment: 14 pages, 2 figure using eps

Yangian Symmetry of smooth Wilson Loops in N=4 super Yang-Mills Theory

We show that appropriately supersymmetrized smooth Maldacena-Wilson loop operators in N=4 super Yang-Mills theory are invariant under a Yangian symmetry Y[psu(2,2|4)] built upon the manifest superconformal symmetry algebra of the theory. The existence of this hidden symmetry is demonstrated at the one-loop order in the weak coupling limit as well as at leading order in the strong coupling limit employing the classical integrability of the dual AdS_5 x S^5 string description. The hidden symmetry generators consist of a canonical non-local second order variational derivative piece acting on the superpath, along with a novel local path dependent contribution. We match the functional form of these Yangian symmetry generators at weak and strong coupling and find evidence for an interpolating function. Our findings represent the smooth counterpart to the Yangian invariance of scattering superamplitudes dual to light-like polygonal super Wilson loops in the N=4 super Yang-Mills theory.Comment: 36 pages, 1 figure. v2: Typos corrected, version to be published in JHE

Impact of thiopurines and anti-tumour necrosis factor therapy on hospitalisation and long-term surgical outcomes in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory condition affecting the large bowel and is associated with a significant risk of both requirement for surgery and the need for hospitalisation. Thiopurines, and more recently, anti-tumour necrosis factor (aTNF) therapy have been used successfully to induce clinical remission. However, there is less data available on whether these agents prevent long-term colectomy rates or the need for hospitalisation. The focus of this article is to review the recent and pertinent literature on the long-term impact of thiopurines and aTNF on long-term surgical and hospitalisation rates in UC. Data from population based longitudinal research indicates that thiopurine therapy probably has a protective role against colectomy, if used in appropriate patients for a sufficient duration. aTNF agents appear to have a short term protective effect against colectomy, but data is limited for longer periods. Whereas there is insufficient evidence that thiopurines affect hospitalisation, evidence favours that aTNF therapy probably reduces the risk of hospitalisation within the first year of use, but it is less clear on whether this effect continues beyond this period. More structured research needs to be conducted to answer these clinically important questions

Modelling and Simulation of Self-regulating Pneumatic Valves

In conventional aircraft energy systems, self-regulating pneumatic valves (SRPVs) are used to control the pressure and mass flow of the bleed air. The dynamic behavior of these valves is complex and dependent on several physical phenomena. In some cases, limit cycles can occur, deteriorating performance. This paper presents a complex multi-physical model of SRPVs implemented in Modelica. First, the working-principle is explained, and common challenges in control-system design-problems related to these valves are illustrated. Then, a Modelica-model is presented in detail, taking into account several physical domains. It is shown, how limit cycle oscillations occurring in aircraft energy systems can be reproduced with this model. The sensitivity of the model regarding both solver options and physical parameters is investigated

Targeting the Anti-Apoptotic Protein c-FLIP for Cancer Therapy

Cellular FLICE (FADD-like IL-1beta-converting enzyme)-inhibitory protein (c-FLIP) is a major resistance factor and critical anti-apoptotic regulator that inhibits tumor necrosis factor-alpha (TNF-alpha), Fas-L, and TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis as well as chemotherapy-triggered apoptosis in malignant cells. c-FLIP is expressed as long (c-FLIPL), short (c-FLIPS), and c-FLIPR splice variants in human cells. c-FLIP binds to FADD and/or caspase-8 or -10 in a ligand-dependent and-independent fashion, which in turn prevents death-inducing signaling complex (DISC) formation and subsequent activation of the caspase cascade. Moreover, c-FLIPL and c-FLIPS are known to have multifunctional roles in various signaling pathways, as well as activating and/or upregulating several cytoprotective signaling molecules. Upregulation of c-FLIP has been found in various tumor types, and its downregulation has been shown to restore apoptosis triggered by cytokines and various chemotherapeutic agents. Hence, c-FLIP is an important target for cancer therapy. For example, small interfering RNAs (siRNAs) that specifically knockdown the expression of c-FLIPL in diverse human cancer cell lines augmented TRAIL-induced DISC recruitment and increased the efficacy of chemotherapeutic agents, thereby enhancing effector caspase stimulation and apoptosis. Moreover, small molecules causing degradation of c-FLIP as well as decreasing mRNA and protein levels of c-FLIPL and c-FLIPS splice variants have been found, and efforts are underway to develop other c-FLIP-targeted cancer therapies. This review focuses on (1) the functional role of c-FLIP splice variants in preventing apoptosis and inducing cytokine and drug resistance; (2) the molecular mechanisms that regulate c-FLIP expression; and (3) strategies to inhibit c-FLIP expression and function

The Signature Center Initiative for the Cure of Glioblastoma

poster abstractGlioblastoma multiforme (GBM, World Health Organization/WHO grade IV) is the most common form of brain cancer in the central nervous system. Although conventional treatment-surgery, radiation, and temozolomide-is somewhat effective in adults, overall survival is still < 15 months. In pediatric patients, morbidity due to GBM is the highest among all pediatric cancers. In the context of brain cancers, new and existing therapeutics typically fail due to heterogeneity of genetic mutations within tumors, and because biologically effective doses of drug cannot be delivered to the primary site and invasive perimeter of the tumor due to the blood brain barrier. The Signature Center Initiative to Cure GBM is a funding mechanism that supports a research portal to foster investigations of the Brain Tumor Working Group for development of effective treatments for the eradication of GBM. The overall mission of the Signature Center Initiative is to: 1. Interrogate the molecular mechanisms of GBM biology and develop interventions that result in improved duration and quality of life for our patients. 2. Stimulate consistent and productive exchange of ideas between clinicians and basic scientists while employing bench-to-bedside and bedside-to-bench strategies to generate and prioritize scientific questions. 3. Provide infrastructure and mentorship needed to successfully compete for external funding. 4. Engage the community through patient advocacy to positively impact brain cancer patient outcomes and enhance philanthropic initiatives. The Brain Tumor Working Group brings together scientists committed to engaging in a team-based approach to study GBM biology. Infrastructure required to advance in vivo humanized intracranial tumor models, drug delivery, target validation, and development of new therapeutic strategies are in place. Additionally a patient sample pipeline to obtain, analyze, and distribute primary patient GBM specimens from the operating room to the research laboratory has been established. In year one of funding, over $70,000 in pilot project funding derived from the Signature Center Initiative and private donations has been distributed to the membership. The Brain Tumor Working Group meets in both small and large group formats to strategize experimental design and grant submissions. A network of basic scientists and clinicians has been developed that provides an effective forum for addressing clinically relevant questions related to GBM. A team-based approach, scientific expertise, and continued development of infrastructure provide our membership with a critical foundation to obtain new knowledge related to understanding how GBM cells evade therapy. In the future, this information can be applied to development of effective treatments that will cure GBM

New approach in numerical simulation of internal ballistics SRM problem

In this article new approach of simulating internal ballistics flows in SRM is considered. Two different phenomena should be taken into account for appropriate numerical simulation of internal ballistics problems: grain propellant regression and flow of combustion gases itself. The simulation is becoming more complicated as these two phenomena depend on each other: grain burning rate depends on flow parameters near the burning surface while flow parameters in SRM depend on current grain propellant position. Previous articles and theses considered complicated geometry of SRM grain but assumed only 1D flows of combustion gases. This assumption can be fulfilled for special types of SRMs but in general it may be far from truth. Thus, numerical schemes capable of simulating 2D and 3D gases flows are needed. This paper focuses on development, description and application of such schemes