A wideband CPW ring power combiner with low insertion loss and high port isolation

In this paper we present a coplanar waveguide (CPW)-based ring power combiner that exhibits less than 0.8 dB insertion loss, better than 15 dB port match and higher than 22 dB isolation loss over the frequency range from 50 GHz to 100 GHz. Compared with the conventional 2-way Wilkinson combiner, the proposed ring power combiner replaces the resistor between the two input ports with two quasi quarter-wave CPWs, a 180º CPW phase inverter, and two resistors that lead to frequency-insensitive port isolation and wideband port match. The power combiner is realized using an electron beam-based GaAs MMIC process along with simple electron beam airbridge technology. These results agree well with 3D full-wave simulations

Phase-sensitive FMCW radar system for high-precision Antarctic ice shelf profile monitoring

Ice shelves fringe much of the Antarctic continent, and, despite being up to 2 km thick, are vulnerable to climate change. Owing to their role in helping to control the ice sheet contribution to sea level change there is great interest in measuring the rate at which they are melting into the ocean. This study describes the development and deployment of an ice-penetrating phase-sensitive FMCW radar, sufficiently robust and with sufficiently low-power consumption to be run through the Antarctic winter as a standalone instrument, yet with the stability and mm-precision needed to detect the very slow changes in ice shelf thickness in this exceptionally demanding environment. A number of elegant processing techniques are described to achieve reliable, high-precision performance and results presented on field data obtained from the Larsen-C ice shelf, Antarctica

Incidence of lymph node metastases in clinical early-stage mucinous and seromucinous ovarian carcinoma: a retrospective cohort study

Objective: The use of lymph node sampling during staging procedures in clinical early-stage mucinous ovarian carcinoma (MOC) is an ongoing matter of debate. Furthermore, the incidence of lymph node metastases (LNM) in MOC in relation to tumour grade (G) is unknown. We aimed to determine the incidence of LNM in clinical early-stage MOC per tumour grade. Design: Retrospective study with data from the Dutch Pathology Registry (PALGA). Setting: The Netherlands, 2002–2012. Population or sample: Patients with MOC. Methods: Histology reports on patients with MOC diagnosed in the Netherlands between 2002 and 2012 were obtained from PALGA. Reports were reviewed for diagnosis, tumour grade and presence of LNM. Clinical data, surgery reports and radiology reports of patients with LNM were retrieved from hospital files. Main outcome measures: Incidence of LNM, disease-free survival (DFS). Results: Of 915 patients with MOC, 426 underwent lymph node sampling. Cytoreductive surgery was performed in 267 patients. The other 222 patients received staging without lymph node sampling. In eight of 426 patients, LNM were discovered by sampling. In four of 190 (2.1%) patients with G1 MOC, LNM were present, compared with one of 115 (0.9%) patients with G2 MOC and three of 22 (13.6%) patients with G3 MOC. Tumour grade was not specified in 99 patients. Patients with clinical early-stage MOC had no DFS benefit from lymph node sampling. Conclusions: LNM are rare in early-stage G1 and G2 MOC without clinical suspicion of LNM. Therefore, lymph node sampling can be omitted in these patients

Incidence of hepatocellular carcinoma in chronic hepatitis B patients receiving nucleos(t)ide therapy: A systematic review

Background & Aims: Chronic hepatitis B patients are at increased risk for hepatocellular carcinoma (HCC). The effect of medium-term nucleos(t)ide analogue therapy on HCC incidence is unclear; therefore, we systematically reviewed all the data on HCC incidence from studies in chronic hepatitis B patients treated with nucleos(t)ide analogues. Methods: We performed a literature search to identify studies with chronic hepatitis B patients treated with nucleos(t)ide analogues for ⩾24months. Results: Twenty-one studies including 3881 treated and 534 untreated patients met our inclusion criteria. HCC was diagnosed in 2.8% and 6.4% of treated and untreated patients, respectively, during a 46 (32–108) month period (p=0.003), in 10.8% and 0.5% of nucleos(t)ide naive patients with and without cirrhosis (p<0.001) and in 17.6% and 0% of lamivudine resistance patients with and without cirrhosis (p<0.001). HCC developed less frequently in nucleos(t)ide naive patients compared to those without virological remission (2.3% vs 7.5%, p<0.001), but there was no difference between lamivudine resistance patients with or without virological response to rescue therapy (5.9% vs 8.8%, p=0.466). Conclusions: Chronic hepatitis B patients receiving medium-term nucleos(t)ide analogue therapy had a significantly lower incidence of HCC compared to untreated patients but treatment does not completely eliminate the risk of HCC. Among the treated patients, cirrhosis, HBeAg negative at baseline and failure to remain in virological remission were associated with an increased risk of HCC

Intravenous immunoglobulin (IVIg) dampens neuronal toll-like receptor-mediated responses in ischemia

10.1186/s12974-015-0294-8Journal of Neuroinflammation12

Micro-SQUID technique for studying the temperature dependence of switching fields of single nanoparticles

An improved micro-SQUID technique is presented allowing us to measure the temperature dependence of the magnetisation switching fields of single nanoparticles well above the critical superconducting temperature of the SQUID. Our first measurements on 3 nm cobalt nanoparticle embedded in a niobium matrix are compared to the Neel Brown model describing the magnetisation reversal by thermal activation over a single anisotropy barrier.Comment: 3 pages, 4 figures; conference proceeding: 1st Joint European Magnetic Symposia (JEMS'01), Grenoble (France), 28th August - 1st September, 200

A Bayesian nonparametric method for detecting rapid changes in disease transmission

Whether an outbreak of infectious disease is likely to grow or dissipate is determined through the time-varying reproduction number, Rt. Real-time or retrospective identification of changes in Rt following the imposition or relaxation of interventions can thus contribute important evidence about disease transmission dynamics which can inform policymaking. Here, we present a method for estimating shifts in Rt within a renewal model framework. Our method, which we call EpiCluster, is a Bayesian nonparametric model based on the Pitman-Yor process. We assume that Rt is piecewise-constant, and the incidence data and priors determine when or whether Rt should change and how many times it should do so throughout the series. We also introduce a prior which induces sparsity over the number of changepoints. Being Bayesian, our approach yields a measure of uncertainty in Rt and its changepoints. EpiCluster is fast, straightforward to use, and we demonstrate that it provides automated detection of rapid changes in transmission, either in real-time or retrospectively, for synthetic data series where the Rt profile is known. We illustrate the practical utility of our method by fitting it to case data of outbreaks of COVID-19 in Australia and Hong Kong, where it finds changepoints coinciding with the imposition of non-pharmaceutical interventions. Bayesian nonparametric methods, such as ours, allow the volume and complexity of the data to dictate the number of parameters required to approximate the process and should find wide application in epidemiology

Nonequilibrium Atom-Dielectric Forces Mediated by a Quantum Field

In this paper we give a first principles microphysics derivation of the nonequilibrium forces between an atom, treated as a three dimensional harmonic oscillator, and a bulk dielectric medium modeled as a continuous lattice of oscillators coupled to a reservoir. We assume no direct interaction between the atom and the medium but there exist mutual influences transmitted via a common electromagnetic field. By employing concepts and techniques of open quantum systems we introduce coarse-graining to the physical variables - the medium, the quantum field and the atom's internal degrees of freedom, in that order - to extract their averaged effects from the lowest tier progressively to the top tier. The first tier of coarse-graining provides the averaged effect of the medium upon the field, quantified by a complex permittivity (in the frequency domain) describing the response of the dielectric to the field in addition to its back action on the field through a stochastic forcing term. The last tier of coarse- graining over the atom's internal degrees of freedom results in an equation of motion for the atom's center of mass from which we can derive the force on the atom. Our nonequilibrium formulation provides a fully dynamical description of the atom's motion including back action effects from all other relevant variables concerned. In the long-time limit we recover the known results for the atom-dielectric force when the combined system is in equilibrium or in a nonequilibrium stationary state.Comment: 24 pages, 2 figure

A Satellite-Based Multi-Pollutant Index of Global Air Quality

Air pollution is a major health hazard that is responsible formillions of annual excess deaths worldwide. Simpleindicators are useful for comparative studies and to asses strends over time. The development of global indicators hasbeen impeded by the lack of ground-based observations in vast regions of the world. Recognition is growing of the need for amultipollutant approach to air quality to better represent human exposure. Here we introduce the prospect of amultipollutant air quality indicator based on observations from satellite remote sensing