Publications by authors named "Bussmann M"

Femtosecond high-intensity laser pulses at intensities surpassing 10 W/cm can generate a diverse range of functional surface nanostructures. Achieving precise control over the production of these functional structures necessitates a thorough understanding of the surface morphology dynamics with nanometer-scale spatial resolution and picosecond-scale temporal resolution. In this study, we show that single XFEL pulses can elucidate structural changes on surfaces induced by laser-generated plasmas using grazing-incidence small-angle X-ray scattering (GISAXS).

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We demonstrate live-updating ptychographic reconstruction with the extended ptychographical iterative engine, an iterative ptychography method, during ongoing data acquisition. The reconstruction starts with a small subset of the total data, and as the acquisition proceeds the data used for reconstruction are extended. This creates a live-updating view of object and illumination that allows monitoring the ongoing experiment and adjusting parameters with quick turn around.

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Application Experiences on a GPU-Accelerated Arm-based HPC Testbed.

Proc Int Conf High Perform Comput Asia Pac Reg HPC Asia 2023 Workshops (2023)

February 2023

This paper assesses and reports the experience of ten teams working to port, validate, and benchmark several High Performance Computing applications on a novel GPU-accelerated Arm testbed system. The testbed consists of eight NVIDIA Arm HPC Developer Kit systems, each one equipped with a server-class Arm CPU from Ampere Computing and two data center GPUs from NVIDIA Corp. The systems are connected together using InfiniBand interconnect.

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Background: The first evaluation of radiotherapy results in patients with breast cancer treated as part of a multimodal oncologic therapy in the Nahe Breast Center is presented. Analysis of the results was performed using an in-practice registry.

Patients And Methods: From September 2016 to December 2017, 138 patients (median age 62.

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Laser plasma-based particle accelerators attract great interest in fields where conventional accelerators reach limits based on size, cost or beam parameters. Despite the fact that particle in cell simulations have predicted several advantageous ion acceleration schemes, laser accelerators have not yet reached their full potential in producing simultaneous high-radiation doses at high particle energies. The most stringent limitation is the lack of a suitable high-repetition rate target that also provides a high degree of control of the plasma conditions required to access these advanced regimes.

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Corynebacterium glutamicum is the major host for the industrial production of amino acids and has become one of the best studied model organisms in microbial biotechnology. Rational strain construction has led to an improvement of producer strains and to a variety of novel producer strains with a broad substrate and product spectrum. A key factor for the success of these approaches is detailed knowledge of transcriptional regulation in C.

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In kraft paper mills, supersonic steam jets are used to remove deposits that build up on the heat exchanger tubes in the recovery boiler. In this study, the fracture toughness and work of fracture, , of simulated boiler deposits were measured at temperatures up to 500 °C to determine the optimal conditions for deposit removal. The model deposits experienced an important brittle to ductile transition at ~450 °C.

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Background: Increasingly, patients with cancer are asking for additional, complementary therapy options for treating the side effects of oncological therapy. Thus, the members of the Breast and Bowel Center Nahe at the Sankt Marienwörth Hospital Bad Kreuznach decided to define the content of this type of counseling for patients before treatment.

Methods: In 2018, a team of internal oncologists, gynecological oncologists, radio-oncologists, nutritionists, psycho-oncologists, and study nurses met several times to define the content of counseling.

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Plasma wakefield accelerators are capable of sustaining gigavolt-per-centimeter accelerating fields, surpassing the electric breakdown threshold in state-of-the-art accelerator modules by 3-4 orders of magnitude. Beam-driven wakefields offer particularly attractive conditions for the generation and acceleration of high-quality beams. However, this scheme relies on kilometer-scale accelerators.

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The [Formula: see text] and [Formula: see text] transitions in Li-like carbon ions stored and cooled at a velocity of [Formula: see text] in the experimental storage ring (ESR) at the GSI Helmholtz Centre in Darmstadt have been investigated in a laser spectroscopy experiment. Resonance wavelengths were obtained using a new continuous-wave UV laser system and a novel extreme UV (XUV) detection system to detect forward emitted fluorescence photons. The results obtained for the two transitions are compared to existing experimental and theoretical data.

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With the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. In addition, an application of X-ray Free-Electron Lasers (XFELs) delivering intense femtosecond X-ray pulses, allows to investigate sample evolution in IR pump - X-ray probe experiments with an unprecedented time resolution. Here we present a detailed study of the periodic plasma created from the colloidal crystal.

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Borderline personality disorder (BPD) is characterized by instability of affect, emotion dysregulation, and interpersonal dysfunction. Especially shame and guilt, so-called self-conscious emotions, are of central clinical relevance to BPD. However, only few experimental studies have focused on shame or guilt in BPD and none investigated their neurobiological underpinnings.

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Background: Impaired oral health affects oral health-related quality of life (OHrQoL) in orthogeriatric hospitalized patients, and both might be associated with potential risk factors for functional impairment, based on the comprehensive geriatric assessment (CGA) and related blood laboratory values. As data on this field are scarce, we investigated possible associations between oral health, items of the geriatric oral health assessment instrument (GOHAI), CGA assessment tools, and relevant laboratory values.

Methods: Explorative cross-sectional pilot study investigating oral and general health, OHrQoL, and functionality based on objective oral health, GOHAI, CGA, and routinely assessed laboratory parameters of orthogeriatric patients.

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In , cyclic adenosine monophosphate (cAMP) serves as an effector of the global transcriptional regulator GlxR. Synthesis of cAMP is catalyzed by the membrane-bound adenylate cyclase CyaB. In this study, we investigated the consequences of decreased intracellular cAMP levels in a Δ mutant.

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We present a conceptual design for a hybrid laser-driven plasma wakefield accelerator (LWFA) to beam-driven plasma wakefield accelerator (PWFA). In this set-up, the output beams from an LWFA stage are used as input beams of a new PWFA stage. In the PWFA stage, a new witness beam of largely increased quality can be produced and accelerated to higher energies.

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Extreme field gradients intrinsic to relativistic laser-interactions with thin solid targets enable compact MeV proton accelerators with unique bunch characteristics. Yet, direct control of the proton beam profile is usually not possible. Here we present a readily applicable all-optical approach to imprint detailed spatial information from the driving laser pulse onto the proton bunch.

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Purpose: Falls are a common cause of morbidity and mortality in older people, and identification of risk indicators and risk factors to prevent falling is essential. Dry mouth (xerostomia and hyposalivation) can exacerbate conditions known to be fall risk indicators, such as nutritional status and sarcopenia. But there is little evidence regarding whether it is an independent risk factor for falling.

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Background: Caregiving relatives of dementia patients are exposed to considerable burdens. A multimodal rehabilitation concept which enables the inpatient treatment of caregiving relatives together with the dementia patients was evaluated.

Methods: Questionnaire survey including 121 caring relatives at 3 times of measurement.

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Purpose: Given its sensitivity to anatomical variations, proton therapy is expected to benefit greatly from integration with magnetic resonance imaging for online anatomy monitoring during irradiation. Such an integration raises several challenges, as both systems mutually interact. The proton beam will experience quasi-continuous energy loss and energy-dependent electromagnetic deflection at the same time, giving rise to a deflected beam trajectory and an altered dose distribution with a displaced Bragg peak.

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Often, the interpretation of experiments concerning the manipulation of the energy distribution of laser-accelerated ion bunches is complicated by the multitude of competing dynamic processes simultaneously contributing to recorded ion signals. Here we demonstrate experimentally the acceleration of a clean proton bunch. This was achieved with a microscopic and three-dimensionally confined near critical density plasma, which evolves from a 1 µm diameter plastic sphere, which is levitated and positioned with micrometer precision in the focus of a Petawatt laser pulse.

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Interaction of relativistic electron beams with high power lasers can both serve as a secondary light source and as a novel diagnostic tool for various beam parameters. For both applications, it is important to understand the dynamics of the inverse Compton scattering mechanism and the dependence of the scattered light's spectral properties on the interacting laser and electron beam parameters. Measurements are easily misinterpreted due to the complex interplay of the interaction parameters.

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For the relativistic Kelvin-Helmholtz instability (KHI), which occurs at shear interfaces between two plasma streams, we report results on the polarized radiation over all observation directions and frequencies emitted by the plasma electrons from ab initio kinetic simulations. We find the polarization of the radiation to provide a clear signature for distinguishing the linear phase of the KHI from its other phases. During the linear phase, we predict the growth rate of the KHI radiation power to match the growth rate of the KHI to a high degree.

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Laser-plasma wakefield accelerators have seen tremendous progress, now capable of producing quasi-monoenergetic electron beams in the GeV energy range with few-femtoseconds bunch duration. Scaling these accelerators to the nanocoulomb range would yield hundreds of kiloamperes peak current and stimulate the next generation of radiation sources covering high-field THz, high-brightness X-ray and γ-ray sources, compact free-electron lasers and laboratory-size beam-driven plasma accelerators. However, accelerators generating such currents operate in the beam loading regime where the accelerating field is strongly modified by the self-fields of the injected bunch, potentially deteriorating key beam parameters.

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We report on recent experimental results deploying a continuous cryogenic hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 10 particles per MeV per steradian is demonstrated, showing for the first time that the acceleration performance is comparable to solid foil targets with thicknesses in the micrometer range. Two different target geometries are presented and their proton beam deliverance characterized: cylindrical (∅ 5 μm) and planar (20 μm × 2 μm).

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