It has already been shown how the shape of the current pulse produced by a SiPM in response to an incident photon is sensibly affected by the characteristics of the front-end electronics (FEE) used ...to read out the detector. When the application requires to approach the best theoretical time performance of the detection system, the influence of all the parasitics associated to the coupling SiPM–FEE can play a relevant role and must be adequately modeled. In particular, it has been reported that the shape of the current pulse is affected by the parasitic inductance of the wiring connection between SiPM and FEE. In this contribution, we extend the validity of a previously presented SiPM model to account for the wiring inductance. Various combinations of the main performance parameters of the FEE (input resistance and bandwidth) have been simulated in order to evaluate their influence on the time accuracy of the detection system, when the time pick-off of each single event is extracted by means of a leading edge discriminator (LED) technique.
Objective
Intracranial electroencephalographic (icEEG) studies show that interictal ripples propagate across the brain of children with medically refractory epilepsy (MRE), and the onset of this ...propagation (ripple onset zone ROZ) estimates the epileptogenic zone. It is still unknown whether we can map this propagation noninvasively. The goal of this study is to map ripples (ripple zone RZ) and their propagation onset (ROZ) using high‐density EEG (HD‐EEG) and magnetoencephalography (MEG), and to estimate their prognostic value in pediatric epilepsy surgery.
Methods
We retrospectively analyzed simultaneous HD‐EEG and MEG data from 28 children with MRE who underwent icEEG and epilepsy surgery. Using electric and magnetic source imaging, we estimated virtual sensors (VSs) at brain locations that matched the icEEG implantation. We detected ripples on VSs, defined the virtual RZ and virtual ROZ, and estimated their distance from icEEG. We assessed the predictive value of resecting virtual RZ and virtual ROZ for postsurgical outcome. Interictal spike localization on HD‐EEG and MEG was also performed and compared with ripples.
Results
We mapped ripple propagation in all patients with HD‐EEG and in 27 (96%) patients with MEG. The distance from icEEG did not differ between HD‐EEG and MEG when mapping the RZ (26–27mm, p = 0.6) or ROZ (22–24mm, p = 0.4). Resecting the virtual ROZ, but not virtual RZ or the sources of spikes, was associated with good outcome for HD‐EEG (p = 0.016) and MEG (p = 0.047).
Interpretation
HD‐EEG and MEG can map interictal ripples and their propagation onset (virtual ROZ). Noninvasively mapping the ripple onset may augment epilepsy surgery planning and improve surgical outcome of children with MRE. ANN NEUROL 2021;89:911–925
The study of RNA structure is fundamental to clarify the RNA molecular functioning. The flexible RNA nature, the huge number of expressed RNAs, and the variety of functions make it challenging to ...obtain a quantity of structural information comparable to what is already available for proteins. The in silico prediction of RNA 3D structures is of particular relevance, to understand the fundamental features of the structure-function relationship, because the 3D structure drives the molecular interaction with DNA or protein complexes. The quality of the prediction of the RNA 3D structure is determined by the knowledge of a properly predicted or measured secondary structure. In this paper, we comparatively evaluate computational tools to model RNA secondary structure, focusing our investigation, among the dozens of methods in literature, on tools which are freely available and implemented in web-server versions, providing a more direct access to the final users, not necessarily bioinformatics experts. Our focus is on assessing performances for long sequences, with the final aim of selecting best methods for perspective lncRNAs investigation. Indeed, among RNAs, the non-coding and long non-coding RNAs (lncRNAs, with sequence length larger than 200 nts) assume special relevance, due to their function in regulatory mechanisms, which is still largely unexplored in the case of lncRNAs. As lncRNA experimental structures are at present missing, other families of large RNAs are here used as test cases, to establish the reliability of predictive bioinformatics tools and their perspective applicability to the case of lncRNAs.
Communicated by Ramaswamy H. Sarma
CMOS analog front-end channel for silicon photo-multipliers Corsi, F.; Foresta, M.; Marzocca, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
A complete self-triggered CMOS analog front-end suitable for silicon photo-multiplier detectors (SiPM) is proposed here, mainly intended for medical imaging applications. The exploitation of a ...current mode approach allows to achieve the large dynamic range and fast timing required by this kind of detectors without excessive power consumption. Results from characterization measurements on the prototype of the analog channel are also reported: the trigger signal produced by the circuit in response to a fast input current pulse exhibits a measured timing accuracy better than 60
ps and a dynamic range of about 50
pC has been obtained.
Abstract
Neurosurgical intervention is the best available treatment for selected patients with drug resistant epilepsy. For these patients, surgical planning requires biomarkers that delineate the ...epileptogenic zone, the brain area that is indispensable for the generation of seizures. Interictal spikes recorded with electrophysiological techniques are considered key biomarkers of epilepsy. Yet, they lack specificity, mostly because they propagate across brain areas forming networks. Understanding the relationship between interictal spike propagation and functional connections among the involved brain areas may help develop novel biomarkers that can delineate the epileptogenic zone with high precision. Here, we reveal the relationship between spike propagation and effective connectivity among onset and areas of spread and assess the prognostic value of resecting these areas.
We analysed intracranial EEG data from 43 children with drug resistant epilepsy who underwent invasive monitoring for neurosurgical planning. Using electric source imaging, we mapped spike propagation in the source domain and identified three zones: onset, early-spread and late-spread. For each zone, we calculated the overlap and distance from surgical resection. We then estimated a virtual sensor for each zone and the direction of information flow among them via Granger causality. Finally, we compared the prognostic value of resecting these zones, the clinically-defined seizure onset zone and the spike onset on intracranial EEG channels by estimating their overlap with resection.
We observed a spike propagation in source space for 37 patients with a median duration of 95 ms (interquartile range: 34–206), a spatial displacement of 14 cm (7.5–22 cm) and a velocity of 0.5 m/s (0.3–0.8 m/s). In patients with good surgical outcome (25 patients, Engel I), the onset had higher overlap with resection 96% (40–100%) than early-spread 86% (34–100%), P = 0.01 and late-spread 59% (12–100%), P = 0.002, and it was also closer to resection than late-spread 5 mm versus 9 mm, P = 0.007. We found an information flow from onset to early-spread in 66% of patients with good outcomes, and from early-spread to onset in 50% of patients with poor outcome. Finally, resection of spike onset, but not area of spike spread or the seizure onset zone, predicted outcome with positive predictive value of 79% and negative predictive value of 56% (P = 0.04).
Spatiotemporal mapping of spike propagation reveals information flow from onset to areas of spread in epilepsy brain. Surgical resection of the spike onset disrupts the epileptogenic network and may render patients with drug resistant epilepsy seizure-free without having to wait for a seizure to occur during intracranial monitoring.
Matarrese et al. provide insights into the pathophysiology of epilepsy by linking spike propagation and effective connectivity. They highlight the clinical value of spike onset as a biomarker that may improve presurgical evaluation and outcome prediction in patients with drug-resistant epilepsy.
Purpose
This manuscript presents a parallel among important EU legal frameworks, such as the Medical Device Regulations and General Data Protection Regulation and economic-historical challenges faced ...by European citizens. This parallel offers a prospective for understanding the direction taken by policymakers for forthcoming regulations, such as the European Health Data Space and the AI-Act.
Method
The paper describes key commonalities and differences among those regulations, which may help scholars working with AI in medicine, navigating this articulated legal framework.
Results
The European Union journey started with the European Coal and Steel Community, enforced after the WWII for nurturing European physical reconstruction and as a mean for peacekeeping: without coil it was not possible to transform steel, and with shared control of steel it was not possible for individual member states to build war weapons.
Conclusions
In this century, modern coal are data and modern steel is the AI, which is a crucial enabler for European economy growth and competitiveness, and, potentially, a powerful war weapon. Ensuring a fair data-sharing and correct use of AI is crucial for sustainable development, peace, and democracy in Europe and beyond.
High-gain photomultiplier detectors are employed in an increasing number of applications in different fields to evaluate with great accuracy the occurrence time of light flashes composed by few or ...even single photons. Examples of these application fields are medical imaging, astroparticle and high energy physics, laser spectroscopy and LIDAR. To fulfill a good single photon timing accuracy, in the range of few hundreds of picoseconds, not only detectors with intrinsic excellent timing resolution (photomultiplier tubes, microchannel plated detectors, silicon photo multipliers, etc.) must be used, but the very first front-end amplifier (FEA) stage, used to read-out the detector, must also be carefully chosen and designed.
We compare here three commonly used solutions for the FEA, from the point of view of the best achievable timing resolution: the charge sensitive amplifier (CSA), the voltage amplifier (VA) and the current buffer (CB). The results show that the CSA solution is limited in terms of frequency response by the usually large equivalent capacitance of the detector and that, surprisingly, the presence of the parasitic inductance L, due to interconnection detector–FEA, has a noise shaping effect which favorably affects the timing accuracy of the CB over the VA configuration. To support this study, simulations of simple implementations of the compared FEA solutions have been performed, under the same conditions.
Moreover, with reference to a given detector and to a particular value of L, we show how the best timing accuracy of the CB is obtained by selecting an appropriate combination of input resistance and bandwidth of the FEA.
•Design issues of the Front-end amplifier of photomultipliers for best timing accuracy.•Comparative study of three classical architectures for the Front-end amplifier.•Effect of the interconnection parasitic inductance L on the maximum timing resolution.•An optimal combination of Front-end parameters can be found for best timing accuracy.
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