Electrical Characterization of SiPM as a Function of Test Frequency and Temperature

Silicon Photomultipliers (SiPM) represent a promising alternative to classical photomultipliers, for instance, for the detection of photons in high energy physics and medical physics. In the present work, electrical characterizations of test devices - manufactured by ST Microelectronics - are presented. SiPMs with an area of 3.5x3.5 micron^2 and a cell pitch of 54 micron were manufactured as arrays of 64x64 cells and exhibiting a fill factor of 31%. The capacitance of SiPMs was measured as a function of reverse bias voltage at frequencies ranging from from 20 Hz up to 1 MHz and temperatures from 300 K down to 85 K. While leakage currents were measured at temperatures from 400 K down to 85 K. Thus, the threshold voltage - i.e., voltage corresponding to that at which the multiplication regime for the leakage current begins - could be determined as a function of temperature. Finally, an electrical model suited to reproduce the dependence of the frequency dependence of capacitance is presented.Comment: To appear on the Proceedings of the 13th ICATPP Conference on Astroparticle, Particle, Space Physics and Detectors for Physics Applications, Villa Olmo (Como, Italy), 3-7 October, 2011, to be published by World Scientific (Singapore

Fiberless, multi-channel fNIRS-EEG system based on silicon photomultipliers: Towards sensitive and ecological mapping of brain activity and neurovascular coupling

Portable neuroimaging technologies can be employed for long-term monitoring of neurophysiological and neuropathological states. Functional Near-Infrared Spectroscopy (fNIRS) and Electroencephalography (EEG) are highly suited for such a purpose. Their multimodal integration allows the evaluation of hemodynamic and electrical brain activity together with neurovascular coupling. An innovative fNIRS-EEG system is here presented. The system integrated a novel continuous-wave fNIRS component and a modified commercial EEG device. fNIRS probing relied on fiberless technology based on light emitting diodes and silicon photomultipliers (SiPMs). SiPMs are sensitive semiconductor detectors, whose large detection area maximizes photon harvesting from the scalp and overcomes limitations of fiberless technology. To optimize the signal-to-noise ratio and avoid fNIRS-EEG interference, a digital lock-in was implemented for fNIRS signal acquisition. A benchtop characterization of the fNIRS component showed its high performances with a noise equivalent power below 1 pW. Moreover, the fNIRS-EEG device was tested in vivo during tasks stimulating visual, motor and pre-frontal cortices. Finally, the capabilities to perform ecological recordings were assessed in clinical settings on one Alzheimer’s Disease patient during long-lasting cognitive tests. The system can pave the way to portable technologies for accurate evaluation of multimodal brain activity, allowing their extensive employment in ecological environments and clinical practice

Effectiveness and safety of adjunctive cenobamate in people with focal-onset epilepsy: Interim results after 24-week observational period from the BLESS study

Objective: Cenobamate is an antiseizure medication (ASM) with a dual mechanism of action that was recently approved for the treatment of focal seizures in adults. This analysis aimed to describe the outcomes at 12 and 24 weeks after starting cenobamate therapy in a real-world setting. Methods: BLESS [NCT05859854] is an ongoing, observational, retrospective and prospective cohort study to evaluate the real-world effectiveness and safety of adjunctive cenobamate in adults with uncontrolled focal epilepsy. Subgroup analysis was performed in subjects with 2 to 3 previous ASMs (early users) and those with >3 previous ASMs (late users). Results: The second interim analysis of the BLESS study included 388 participants with a median (interquartile range) age of 43.0 (31.0-54.0) years. They had a median of 6.0 (4.0-9.0) prior ASMs and a median of 7.2 (3.0-20.6) monthly seizures at baseline. The median monthly seizure frequency was reduced by 59.9% (19.2%-87.3%) from baseline to 24 weeks; 229 (59.0%) subjects had a >= 50% seizure frequency reduction, and 44 (11.3%) showed sustained seizure freedom. The proportion of participants taking <= 2 concomitant ASMs increased from 217 (56.5%) at baseline to 239 (65.7%) at 24 weeks. Among the early users (n = 76, 19.6%), the median reduction in monthly seizure frequency at 24 weeks was 78.0% (50.0-97.1%), and 76.3% of subjects had a >= 50% response rate. The frequency of adverse drug reactions (ADRs) was 5.3% and 23.4% in early and late users. The most frequent ADRs were somnolence, dizziness, and balance disorder; after the occurrence of ADRs, 63.5% of participants maintained the prescribed dose, and 5.2% permanently discontinued treatment. Significance: Cenobamate was effective in reducing seizure frequency in a real-world setting and showed a manageable safety profile. The treatment with cenobamate also reduced the burden of concomitant ASMs in both early and late users

Prognostic factors and impact of management strategies for status epilepticus: The STEPPER study in the Emilia-Romagna region, Italy

Objective: The STEPPER (Status Epilepticus in Emilia-Romagna) study aimed to investigate the clinical characteristics, prognostic factors, and treatment approaches of status epilepticus (SE) in adults of the Emilia-Romagna region (ERR), Northern Italy. Methods: STEPPER, an observational, prospective, multicentric cohort study, was conducted across neurology units, emergency departments, and intensive care units of the ERR over 24 months (October 2019–October 2021), encompassing incident cases of SE. Patients were followed up for 30 days. Results: A total of 578 cases were recruited (56% female, mean age = 70 years, 32% with previous diagnosis of epilepsy, 43% with in-hospital onset, 35% stuporous/comatose, 46% with nonconvulsive SE). Etiology was known in 87% (acute 43%, remote 24%, progressive 17%, definite epileptic syndrome 3%). The mean pre-SE Rankin Scale score was 2, the Status Epilepticus Severity Score was ≥4 in 33%, the Epidemiology-Based Mortality Score in Status Epilepticus score was ≥64 in 61%, and 34% were refractory. The sequence of treatments followed current clinical practice guidelines in 63%. Benzodiazepines (BDZs) were underused as first-line therapy (71%), especially in in-hospital onset cases; 15% were treated with continuous intravenous anesthetic drugs. Mortality was 24%; 63% of survivors had functional worsening. At the two-step multivariable analysis, incorrect versus correct treatment sequence with correct BDZ dose was the strongest predictor of failure to resolve SE in the in-hospital group (odds ratio [OR] = 4.42, 95% confidence interval [CI] = 1.86–10.5), with a similar trend in the out-of-hospital group (OR = 2.22, 95% CI =.98–5.02). In turn, failure to resolve was the strongest predictor of 30-day mortality (OR = 11.3, 95% CI = 4.16–30.9, out-of-hospital SE; OR = 6.42, 95% CI = 2.79–14.8, in-hospital SE) and functional worsening (OR = 5.83, 95% CI = 2.05–16.6, out-of-hospital SE; OR = 9.30, 95% CI 2.22–32.3, in-hospital SE). Significance: The STEPPER study offers insights into real-world SE management, highlighting its significant morbidity and functional decline implications. Although nonmodifiable clinical factors contribute to SE severity, modifiable factors such as optimized first-line therapies and adherence to guidelines can potentially influence prognosis

Construction and characterization of the detection modules for the Muon Portal Project

The Muon Portal Project is a joint initiative between research and industrial partners, aimed at the construction of a real size detector protoype (6×3×7 m3) for the inspection of containers by the muon scattering technique, devised to search for hidden high-Z fissile materials and provide a full 3D tomography of the interior of the container in a scanning time of the order of minutes. The muon tracking detector is based on a set of 48 detection modules (size 1 m × 3 m), each built with 100 extruded scintillator strips, so as to provide four X-Y detection planes, two placed above and two below the container to be inspected. Two wavelength shifting (WLS) fibres embedded in each strip convey the emitted photons to Silicon Photomultipliers (SiPM) which act as photosensors. After a research and development phase, which led to the choice and test of the individual components, the construction of the full size detector has already started. The paper describes the results of the mass characterization of the photosensors and the construction and test measurements of the first detection modules of the Project

Expression of 19 microRNAs in glioblastoma and comparison with other brain neoplasia of grades I-III

Several biomarkers have been proposed as useful parameters to better specify the prognosis or to delineate new target therapy strategies for glioblastoma patients. MicroRNAs could represent putative target molecules, considering their role in tumorigenesis, cancer progression and their specific tissue expression. Although several studies have tried to identify microRNA signature for glioblastoma, a microRNA profile is still far from being well-defined. In this work the expression of 19 microRNAs (miR-7, miR-9, miR-9 17, miR-10a, miR-10b, miR-17, miR-20a, miR-21, miR-26a, miR-27a, miR-31, miR-34a, miR-101, miR-137, miR-182, miR-221, miR-222, miR-330, miR-519d) was evaluated in sixty formalin-fixed and paraffin-embedded glioblastoma samples using a locked nucleic acid real-time PCR. Moreover, a comparison of miRNA expressions was performed between primary brain neoplasias of different grades (grades IV-I). The analysis of 14 validated miRNA expression in the 60 glioblastomas, using three different non-neoplastic references as controls, revealed a putative miRNA signature: mir-10b and miR-21 were up-regulated, while miR-7, miR-31, miR-101, miR-137, miR-222 and miR-330 were down-regulated in glioblastomas. Comparing miRNA expression between glioblastoma group and gliomas of grades I-III, 3 miRNAs (miR-10b, mir-34a and miR-101) showed different regulation statuses between high-grade and low-grade tumors. miR-10b was up-regulated in high grade and significantly down-regulated in low-grade gliomas, suggesting that could be a candidate for a GBM target therapy. This study provides further data for the identification of a miRNA profile for glioblastoma and suggests that different-grade neoplasia could be characterized by different expression of specific miRNA

miRNAs Expression Analysis in Paired Fresh/Frozen and Dissected Formalin Fixed and Paraffin Embedded Glioblastoma Using Real-Time PCR

miRNAs are small molecules involved in gene regulation. Each tissue shows a characteristic miRNAs epression profile that could be altered during neoplastic transformation. Glioblastoma is the most aggressive brain tumour of the adult with a high rate of mortality. Recognizing a specific pattern of miRNAs for GBM could provide further boost for target therapy. The availability of fresh tissue for brain specimens is often limited and for this reason the possibility of starting from formalin fixed and paraffin embedded tissue (FFPE) could very helpful even in miRNAs expression analysis. We analysed a panel of 19 miRNAs in 30 paired samples starting both from FFPE and Fresh/Frozen material. Our data revealed that there is a good correlation in results obtained from FFPE in comparison with those obtained analysing miRNAs extracted from Fresh/Frozen specimen. In the few cases with a not good correlation value we noticed that the discrepancy could be due to dissection performed in FFPE samples. To the best of our knowledge this is the first paper demonstrating that the results obtained in miRNAs analysis using Real-Time PCR starting from FFPE specimens of glioblastoma are comparable with those obtained in Fresh/Frozen samples

Adjunctive Brivaracetam in People with Epilepsy and Intellectual Disability: Evidence from the BRIVAracetam Add-On First Italian netwoRk Study

Introduction: Subjects with intellectual disability are usually excluded from clinical trials and there is limited evidence-based guidance for the choice of antiseizure medications in this vulnerable population. The study explored the effectiveness of brivaracetam (BRV) in people with epilepsy and intellectual disability. Methods: BRIVAracetam add-on First Italian netwoRk Study (BRIVAFIRST) was a 12-month retrospective, multicenter study including adults prescribed adjunctive BRV. Main outcomes included the rates of seizure‐freedom, seizure response (≥ 50% reduction in baseline seizure frequency), and treatment discontinuation. The occurrence of adverse events (AEs) was also considered. Analyses by the presence and severity of intellectual disability were performed. Results: Subjects with intellectual disability were 253 (24.6%) out of 1029 participants. The 12-month rates of seizure freedom were 18.4% and 10.3% in participants without and with intellectual disability, respectively; the corresponding values for seizure response were 40.0% and 28.9%. Intellectual disability was not an independent predictor of seizure outcomes. The rates of treatment discontinuation were 25.8% and 26.4% in participants without and with intellectual disability. respectively. There were no statistically significant differences in the rates of any AEs, somnolence, nervousness/agitation, and aggressiveness by the presence and degree of intellectual disability. Conclusion: Brivaracetam can be a suitable treatment option and offer opportunities for clinical improvement in subjects with intellectual disability and uncontrolled seizures