A Scanned Perturbation Technique For Imaging Electromagnetic Standing Wave Patterns of Microwave Cavities

We have developed a method to measure the electric field standing wave distributions in a microwave resonator using a scanned perturbation technique. Fast and reliable solutions to the Helmholtz equation (and to the Schrodinger equation for two dimensional systems) with arbitrarily-shaped boundaries are obtained. We use a pin perturbation to image primarily the microwave electric field amplitude, and we demonstrate the ability to image broken time-reversal symmetry standing wave patterns produced with a magnetized ferrite in the cavity. The whole cavity, including areas very close to the walls, can be imaged using this technique with high spatial resolution over a broad range of frequencies.Comment: To be published in Review of Scientific Instruments,September, 199

A Statistical Mechanical Load Balancer for the Web

The maximum entropy principle from statistical mechanics states that a closed system attains an equilibrium distribution that maximizes its entropy. We first show that for graphs with fixed number of edges one can define a stochastic edge dynamic that can serve as an effective thermalization scheme, and hence, the underlying graphs are expected to attain their maximum-entropy states, which turn out to be Erdos-Renyi (ER) random graphs. We next show that (i) a rate-equation based analysis of node degree distribution does indeed confirm the maximum-entropy principle, and (ii) the edge dynamic can be effectively implemented using short random walks on the underlying graphs, leading to a local algorithm for the generation of ER random graphs. The resulting statistical mechanical system can be adapted to provide a distributed and local (i.e., without any centralized monitoring) mechanism for load balancing, which can have a significant impact in increasing the efficiency and utilization of both the Internet (e.g., efficient web mirroring), and large-scale computing infrastructure (e.g., cluster and grid computing).Comment: 11 Pages, 5 Postscript figures; added references, expanded on protocol discussio

Targeting FGFR inhibition in cholangiocarcinoma

Cholangiocarcinomas (CCAs) are rare but aggressive tumours of the bile ducts, which are often diagnosed at an advanced stage and have poor outcomes on systemic therapy. Somatic alterations with therapeutic implications have been identified in almost half of CCAs, in particular in intrahepatic CCA (iCCA), the subtype arising from bile ducts within the liver. Among patients with CCA, fibroblast growth factor receptor 2 (FGFR2) fusions or rearrangements occur almost exclusively in iCCA, where they are estimated to be found in up to 10–15% of patients. Clinical trials for selective FGFR kinase inhibitors have shown consistent activity of these agents in previously treated patients with iCCA harbouring FGFR alterations. Current FGFR kinase inhibitors show differences in their structure, mechanisms of target engagement, and specificities for FGFR1, 2, 3 and 4 and other related kinases. These agents offer the potential to improve outcomes in FGFR-driven CCA, and the impact of variations in the molecular profiles of the FGFR inhibitors on efficacy, safety, acquired resistance mechanisms, and patients’ health-related quality of life remains to be fully characterized. The most common adverse event associated with FGFR inhibitors is hyperphosphatemia, an on-target off-tumour effect of FGFR1 inhibition, and strategies to manage this include dose adjustment, chelators, and the use of a low phosphate diet. As FGFR inhibitors and other targeted agents enter the clinic for use in FGFR-driven CCA, molecular testing for actionable mutations and monitoring for the emergence of acquired resistance will be essential

Cholangiocarcinoma miscoding in hepatobiliary centres

INTRODUCTION: Cholangiocarcinoma (CCA) are sub-divided into intrahepatic (iCCA) or extrahepatic (eCCA). eCCA are further subdivided into perihilar (pCCA) and distal (dCCA). Current and previous versions of the WHO International Coding of Disease and Oncology classifications (ICD) have separate topography codes for iCCA and eCCA, but none for pCCA. Over recent decades, multiple studies report rising incidence rates of iCCA with declining rates of eCCA, without reference to pCCA. We hypothesised the lack of a specific code for pCCA has led to errors CCA coding, specifically with miscoding of pCCA as iCCA. METHODS: Clinical notes of cases coded as hepatobiliary carcinoma using ICD-10 criteria (C22.1/Intrahepatic Bile Duct carcinoma, C24.0/Extrahepatic Bile Duct carcinoma, C23X/Malignant Neoplasm Gall Bladder, C22.0/Malignant Neoplasm Liver Cell Carcinoma) over a 2 year period (2015-2017), were reviewed by two independent clinicians at three independent UK regional HepatoPancreatoBiliary centres. The agreed final diagnosis was compared to the originally allocated ICD-10 code. RESULTS: Of the 625 CCA cases fully reviewed, 226 were coded as C22.1/iCCA. 98 (43%) of these were true iCCA and coded correctly, while 76 cases (34%) were actually pCCA. 92% all pCCA cases were incorrectly coded as iCCA. CONCLUSION: CCA coding misclassification in UK HPB centres is common, particularly the miscoding of pCCA, which is extrahepatic and the commonest form of CCA, as iCCA. This may be contributing to apparent rising incidence rates of iCCA. Our findings confirm the need to implement distinct topographical codes for iCCA, pCCA and dCCA in future iterations of ICD

Traveling Granular Segregation Patterns in a Long Drum Mixer

Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in certain mixtures: bi-directional traveling waves. By preparing initial conditions, we found that the wave speed decreased with wavelength. Such waves appear to be inconsistent with simple PDE models which are first order in time.Comment: 11 page