Publications by authors named "Sander T"

Article Synopsis
  • Dystonia is a movement disorder linked to an imbalance in brain pathways involving the striatum and internal pallidum, but its neuronal causes are not fully understood.
  • This study conducted invasive recordings from ten dystonia patients using deep brain stimulation electrodes to observe brain activity across different basal ganglia nuclei.
  • Findings showed that low-frequency brain activity between the striatum and internal pallidum correlates with the severity of dystonic symptoms, highlighting the importance of the direct striato-pallidal pathway in the disorder's development.
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Magnetoencephalography (MEG) allows the non-invasive measurement of brain activity at millisecond precision combined with localization of the underlying generators. So far, MEG-systems consisted of superconducting quantum interference devices (SQUIDS), which suffer from several limitations. Recent technological advances, however, have enabled the development of novel MEG-systems based on optically pumped magnetometers (OPMs), offering several advantages over conventional SQUID-MEG systems.

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Knowledge about the 3-dimensional structure, orientation and interaction of chemical compounds is important in many areas of science and technology. X-ray crystallography is one of the experimental techniques capable of providing a large amount of structural information for a given compound, and it is widely used for characterisation of organic and metal-organic molecules. The method provides precise 3D coordinates of atoms inside crystals, however, it does not directly deliver information about certain chemical characteristics such as bond orders, delocalization, charges, lone electron pairs or lone electrons.

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Purpose: Fasting guidelines for children recommend restricting clear fluids for one or two hours before a procedure to reduce pulmonary aspiration. Gastric volumes < 1.5 mL·kg do not seem to present an increased risk of pulmonary aspiration.

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We present an efficient algorithm for substructure search in combinatorial libraries defined by synthons, i.e., substructures with connection points.

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Thermal noise magnetometry (TNM) is a recently developed magnetic characterization technique where thermally induced fluctuations in magnetization are measured to gain insight into nanomagnetic structures like magnetic nanoparticles (MNPs). Due to the stochastic nature of the method, its signal amplitude scales with the square of the volume of the individual fluctuators, which makes the method therefore extra attractive to study MNP clustering and aggregation processes. Until now, TNM signals have exclusively been detected by using a superconducting quantum interference device (SQUID) sensor.

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Article Synopsis
  • Alanine is highly effective as a secondary standard detector in cancer radiation therapy for MV photon energies, achieving over 1% accuracy, but shows large uncertainties at low keV x-ray energies.
  • The study involved irradiating 0.5 mm thick alanine pellets with monoenergetic x-rays at the Diamond Light Source to gauge their response in the 8-20 keV range compared to cobalt radiation.
  • Results indicated a relative response between 0.616 and 0.643, with a combined uncertainty of 3.4%-3.5%, and the findings support the use of alanine as a secondary dosimeter for low-energy x-ray sources.
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Robust preclinical models are inevitable for researchers to unravel pathomechanisms of subarachnoidal hemorrhage (SAH). For the mouse perforation model of SAH, the goal of this meta-review was the determination of variances in mortality, SAH severity grade, and vasospasm, and their experimental moderators, as many researchers are facing with incomparable results. We searched on the databases PubMed, Embase, and Web of Science for articles describing in vivo experiments using the SAH perforation mouse model and measuring mortality, SAH grade, and/or vasospasm.

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Introduction: Musculoskeletal injuries (MSKIs) are ubiquitous during initial entry military training, with overuse injuries the most common. A common injury mechanism is running, an activity that is integral to US Coast Guard (USCG) training and a requirement for graduation. The purpose of this study was to assess the effects of a policy that allowed for athletic footwear choice on risk of lower quarter MSKI in USCG recruits.

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Transcranial magnetic stimulation (TMS) has widespread clinical applications from diagnosis to treatment. We combined TMS with non-contact magnetic detection of TMS-evoked muscle activity in peripheral limbs to explore a new diagnostic modality that enhances the utility of TMS as a clinical tool by leveraging technological advances in magnetometry. We recorded measurements in a regular hospital room using an array of optically pumped magnetometers (OPMs) inside a portable shield that encloses only the forearm and hand of the subject.

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Objectives: Heterogeneity of results of exact same research experiments oppose a significant socioeconomic burden. Insufficient methodological reporting is likely to be one of the contributors to results heterogeneity; however, little knowledge on reporting habits of in vitro cancer research and their effects on results reproducibility is available. Exemplified by a commonly performed in vitro assay, we aim to fill this knowledge gap and to derive recommendations necessary for reproducible, robust and translational preclinical science.

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Cleaving single crystals in situ under ultra-high vacuum conditions provides a reliable and straightforward approach to prepare clean and atomically well-defined surfaces. Here, we present a versatile sample cleaver to efficiently prepare ionic crystal surfaces under ultra-high vacuum conditions, which is suitable for preparation of softer materials, such as alkali halides, and harder materials, such as metal oxides. One of the advantages of the presented cleaver design is that the cleaving blade and anvil to support the crystal are incorporated into the device.

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Magnetoencephalography (MEG) is a neuroimaging technique that measures the magnetic fields of the brain outside of the head. In the past, the most suitable magnetometer for MEG was the superconducting quantum interference device (SQUID), but in recent years, a new type has also been used, the optically pumped magnetometer (OPM). OPMs can be configured to measure multiple directions of magnetic field simultaneously.

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The subthalamic nucleus (STN) is a primary target for deep brain stimulation in Parkinson's disease (PD). Although small in size, the STN is commonly partitioned into sensorimotor, cognitive/associative, and limbic subregions based on its structural connectivity profile to cortical areas. We investigated whether such a regional specialization is also supported by functional connectivity between local field potential recordings and simultaneous magnetoencephalography.

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In drug discovery, molecules are optimized towards desired properties. In this context, machine learning is used for extrapolation in drug discovery projects. The limits of extrapolation for regression models are known.

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Synthetically accessible chemical spaces provide a valuable source to search for small-molecule analogues or new starting points in drug discovery projects. Having a toolbox at hand that can automatically create searchable representations of such spaces using reaction definitions and building blocks as inputs is a prerequisite to put this approach into practice. Herein, we present a tool kit to create such virtual chemical spaces.

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Optically pumped magnetometers (OPMs) have recently become so sensitive that they are suitable for use in magnetoencephalography (MEG). These sensors solve operational problems of the current standard MEG, where superconducting quantum interference device (SQUID) gradiometers and magnetometers are being used. The main advantage of OPMs is that they do not require cryogenics for cooling.

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Recent developments in performance and practicality of optically-pumped magnetometers (OPMs) have enabled new capabilities in non-invasive brain function mapping through magnetoencephalography. In particular, the lack of cryogenic operating conditions allows for more flexible placement of sensor heads closer to the brain, leading to improved spatial resolution and source localisation capabilities. Through recording visually evoked brain fields (VEFs), we demonstrate that the closer sensor proximity can be exploited to improve temporal resolution.

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Background: Analyses of few gene-sets in epilepsy showed a potential to unravel key disease associations. We set out to investigate the burden of ultra-rare variants (URVs) in a comprehensive range of biologically informed gene-sets presumed to be implicated in epileptogenesis.

Methods: The burden of 12 URV types in 92 gene-sets was compared between cases and controls using whole exome sequencing data from individuals of European descent with developmental and epileptic encephalopathies (DEE, n = 1,003), genetic generalized epilepsy (GGE, n = 3,064), or non-acquired focal epilepsy (NAFE, n = 3,522), collected by the Epi25 Collaborative, compared to 3,962 ancestry-matched controls.

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Objective: To compare the effectiveness of different mask types in limiting the dispersal of coughed air.

Method: The Schlieren method with a single curved mirror was used in this study. Coughed air has a slightly higher temperature than ambient air, which generates a refractive index gradient.

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Cancer cells, like microbes, live in complex metabolic environments. Recent evidence suggests that microbial behavior across metabolic environments is well described by simple empirical growth relationships, or growth laws. Do such empirical growth relationships also exist in cancer cells? To test this question, we develop a high-throughput approach to extract quantitative measurements of cancer cell behaviors in systematically altered metabolic environments.

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Increasing evidence indicates the pathogenetic relevance of regulatory genomic motifs for variability in the manifestation of brain disorders. In this context, cis-regulatory effects of single nucleotide polymorphisms (SNPs) on gene expression can contribute to changing transcript levels of excitability-relevant molecules and episodic seizure manifestation in epilepsy. Biopsy specimens of patients undergoing epilepsy surgery for seizure relief provide unique insights into the impact of promoter SNPs on corresponding mRNA expression.

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Using fMRI, a core evaluation mechanism was found for aesthetic judgments with add-on neural activities for moral and commercial judgments. We propose that aesthetic evaluations serve as a basic core mechanism implicitly for moral and commercial judgments.

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