A diagnostic study comparing conventional and real-time PCR for Strongyloides stercoralis on urine and on faecal samples

Abstract Strongyloides stercoralis is a soil-transmitted helminth with a wide distribution in tropical and subtropical areas. The diagnosis of S. stercoralisinfection can be challenging, due to the low sensitivity of microscopic examination of stool samples and coproculture. In the last decade, different in-house molecular biology techniques for S. stercoralis have been implemented. They demonstrated good accuracy, although sensitivity does not seem sufficiently high yet. Recently, a novel PCR technique has been evaluated for the detection of S. stercoralis DNA in urine. Aim of this work was to compare the sensitivity of the real-time PCR (qPCR) on feces routinely used at the Centre for Tropical Disease (CTD) of Negrar, Verona, Italy, with that of the novel based PCR on urine. As secondary objective, we evaluated a Urine Conditioning Buffer ® (Zymoresearch) with the aim of improving nucleic acid stability in urine during sample storage/transport at ambient temperatures. Patients attending the CTD and resulting positive at routine screening with serology for S. stercoralis were invited, previous written consent, to supply stool and urine samples for molecular biology. A convenience sample of 30 patients was included. The sensitivity of qPCR on feces resulted 63%, and that of based PCR on urine was 17%. In all the samples treated with the Urine Conditioning Buffer ® there was no detectable DNA. In conclusion, the sensitivity of the novel technique resulted low, and needs further implementation before being considered as a valid alternative to the validated method

Active deep learning for nonlinear optics design of a vertical FFA accelerator

Vertical Fixed-Field Alternating Gradient (vFFA) accelerators exhibit particle orbits which move vertically during acceleration. This recently rediscovered circular accelerator type has several advantages over conventional ring accelerators, such as zero momentum compaction factor. At the same time, inherently non-planar orbits and a unique transverse coupling make controlling the beam dynamics a complex task. In general, betatron tune adjustment is crucial to avoid resonances, particularly when space charge effects are present. Due to highly nonlinear magnetic fields in the vFFA, it remains a challenging task to determine an optimal lattice design in terms of maximising the dynamic aperture. This contribution describes a deep learning based algorithm which strongly improves on regular grid scans and random search to find an optimal lattice: a surrogate model is built iteratively from simulations with varying lattice parameters to predict the dynamic aperture. The training of the model follows an active learning paradigm, which thus considerably reduces the number of samples needed from the computationally expensive simulations

Online fit of an analytical response matrix model for orbit correction and optical function measurement

At the Karlsruhe Research Accelerator (KARA), an analytical online model of the orbit response matrix (ORM) has been developed and tested. The model, called the bilinear-exponential model with dispersion (BE+d model), is derived from the Mais-Ripken formalism describing coupled betatron motion. Compared to the standard approach of measuring the ORM, this method continuously adapts to changing beam optics without a dedicated measurement. It is especially useful for storage rings without turn-by-turn capable beam position monitors (BPMs) as the online model also gives access to estimates of the coupled optical functions. In the following, experimental orbit correction results and a comparison of fitted and simulated optical functions are presented

Split-ring resonator experiments and data analysis at FLUTE

FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a compact linac-based test facility for accelerator and diagnostics R&D located at the Karlsruher Institute of Technology (KIT). A new accelerator diagnostics tool, called the split-ring resonator (SRR), was tested at FLUTE, which aims at measuring the longitudinal bunch profile of fs-scale electron bunches. Laser-generated THz radiation is used to excite a high frequency oscillating electromagnetic field in the SRR. Electrons passing through the 20 µm x 20 µm SRR gap are time-dependently deflected in the vertical plane, leading to a vertical streaking of the electron bunch. During the commissioning of the SRR at FLUTE, large series of streaking attempts with varying machine parameters and set-ups were investigated in an automatized way. The recorded beam screen images during this experiment have been analyzed and evaluated. This contribution motivates and presents the automatized experiment and discusses the data analysis

Investigations on NbTi superconducting racetrack coils under pulsed-current excitations

One of the key issues in the technology of superconductors is the protection against quenches. When designing a superconductor as a magnet, a coil or even current leads, the design should be made such that the superconductor withstands all operational conditions as fast discharges, pulsed loads or even rapid transient background fields. Computational modeling of pulsed-current characterization in a self-field NbTi racetrack sample coil has been performed using the finite element modelling software Opera as a step towards understanding the thermal and electromagnetic processes during a quench. The pulse was modelled to be generated by discharging a capacitor into an RLC circuit, which includes the NbTi racetrack coil as the sample under test. The coil was driven to the resistive state and the quench occurred by applying the pulse with a peak value exceeding the critical current of the sample coil. This contribution presents the results obtained from investigating a pulsed NbTi coil in a model based on an electromagnetic analysis. In addition, a comparison to the theoretical expectations derived for the damped oscillations in the pulse-driving circuit is given. Finally, the results from a coupled analysis, where both thermal and electromagnetic properties are being considered, within a quench multi-physics study are presented

Characterization and optimization of laser-generated THz beam for THz based streaking

At the Ferninfrarot Linac- und Test-Experiment (FLUTE) at the Karlsruhe Institute of Technology (KIT) a new and compact method for longitudinal diagnostics of ultrashort electron bunches is being developed. For this technique, which is based on THz streaking, strong electromagnetic pulses with frequencies around 240 GHz are required. Therefore, a setup for laser-generated THz radiation using tilted-pulse-front pumping in lithium niobate was designed, delivering up to 1 µJ of THz pulse energy with a conversion efficiency of up to 0.03 %. In this contribution we study the optimization of the THz beam transport and environment

Commissioning of a 1.6 m long 16mm period superconducting undulator at the Australian Synchrotron

A 1.6 m long 16 mm period superconducting undulator (SCU16) has been installed and commissioned at the Australian Synchrotron. The SCU16, developed by Bilfinger Noell GmbH, is based on the SCU20 currently operating at at KIT. The SCU16 is conduction cooled with a maximum on axis field of 1.084 T and a fixed effective vacuum gap of 5.5 mm. The design and performance of the longest superconducting undulator at a light source will be presented

A low-latency feedback system for the control of horizontal betatron oscillations

Reinforcement learning (RL) algorithms are investigated at KIT as an option to control the beam dynamics at storage rings. These methods require specialized hardware to satisfy throughput and latency constraints dictated by the timescale of the relevant phenomena. The KINGFISHER platform, based on the novel Xilinx Versal Adaptive Compute and Acceleration Platform, is an ideal candidate to deploy RL-on-a-chip thanks to its ability to execute computationally intensive and low latency feedback loops in the order of tens of microseconds. In this publication, we will present the integration of the KINGFISHER system at the Karlsruhe Research Accelerator (KARA), as a proof-of-principle turn-by-turn control feedback loop, to control induced transversal oscillations of an electron beam

Electron beam test facilities for novel applications

Delivering and tailoring high brightness electron beams for a wide range of novel applications is a challenging task in single pass accelerator test facilities. This paper will review beam dynamics challenges at single pass accelerator test facilities in Europe to generate, transport and tailor low- to medium-energy high brightness electron beams for a range of novel applications

Prospects for photon science and beam dynamics studies of a THz undulator at FLUTE

n recent years the interest in high intensity, short-pulse coherent THz radiation for non-linear experimental research and applications grew with upcoming high intensity lasers. In contrast to lasers, accelerators provide free electrons for which emission properties can be tailored to the demand at typically much higher repetition rates than high-intensity lasers can provide. Efforts are ongoing to augment short-bunch accelerators such as the European XFEL with THz radiation sources such as undulators. At the far-infrared linac and test experiment (FLUTE) at KIT, we can facil- itate experiments to investigate coherent THz radiation from different sources and provide short electron bunches. As an additional THz source, a superconducting undulator can be inserted and investigated. In this contribution, we evaluate the opportunities of this THz undulator at FLUTE for linear accelerators and FELs in terms of photon science and beam dynamics