INTRODUCTION: Surgery of craniopharyngiomas and skull base chordomas represents a challenge even for experienced surgeons. Although a safe strategy of treatment does not exist, many options can be ...considered to manage this baffling problem. The aim of this study is to describe the evolution from traditional open surgery to the application of the endoscopic endonasal technique and compare the different surgical approaches establishing the validity of each procedure, in order to propose a valid and safe treatment algorithm. METHODS: A retrospective analysis was conducted on 130 patients aged between 3 and 84 years who underwent surgical procedures for craniopharyngioma in the decade 1993-2013 and 16 patients aged between 13 and 85 years affected by skull base chordomas who underwent surgical treatment at the Besta Neurological Institute in the last four years (2010-2014). The plan of treatment and the surgical procedure used for each patient, were object of critical essay. RESULTS: Overall, 170 surgical procedures were performed for primitive and recurrent craniopharyngiomas on 130 patients. The pterional approach was used in 104 cases, followed by four hands-four eyes endoscopic endonasal in 23 cases, inter-hemipheric trans-lamina terminalis in 19, stereotactic local interferon administration and endoscopic procedures for intracystic fluid drainage in 17 and others approaches in 7. In the skull base chordoma group, 10 patients underwent an endoscopic endonasal approach to the skull base. The other patients were treated as follows: 5 fully microscopic approach (2 facial degloving, 2 far lateral approaches and 1 transpetrous) and one transnasal microscopic endoscopic-assisted approach. CONCLUSIONS: Although the period of the study showed the strong presence of the open microsurgery approaches, the selective analysis of the last four years showed a dramatic change of the surgical options in support of as less invasive as efficacious ones. The use of traditional approaches, still indicated in few cases, is constantly decreasing in recent years. A "maximal safe resection" followed by adjuvant therapies should guarantee a good compromise between survival and quality of life with lower mortality and morbidity for craniopharyngioma and skull base chordoma patients.
Silicon photomultipliers (SiPMs) are highly-sensitive photodetectors emerging as the technology of choice for many applications, including among the others, large high-energy physics experiments and ...detectors for space instruments, where they are often exposed to a large amount of radiation. In recent years, there has been an increasing interest in assessing the performance deterioration of such detectors after ionizing and non-ionizing radiation, such as protons, neutrons and X or gamma rays. It is therefore interesting to characterize the effect of irradiation on such Geiger-mode detectors, differentiating between the ionizing and non-ionizing energy-loss effects. Moreover, it is interesting to compare the radiation damage effects on several types of SiPMs, to assess the main phenomena and the deterioration mechanisms, aiming to a more radiation tolerant SiPM design.
In this work we irradiated several types of SiPM structures, produced in FBK (Trento, Italy), with 40 keV X-rays, at several doses, up to 100 kGy (in silicon), performing both online measurements (after each irradiation step) and offline functional characterization, after one month of room temperature annealing. The SiPMs are made with many different technologies, in particular different layouts, junction polarities, internal structures and starting materials. We studied the variation in the reverse current–voltage curves, distinguishing the effects on multiplied and not-multiplied current components, the primary dark count rate, the correlated noise probabilities and photon detection efficiency. Comparing all the measurement results, knowing the internal structure and the fabrication processes, we were able to extract and distinguish different deterioration mechanisms, also supported by TCAD simulations on the different effects of ionizing radiation inside the microcells.
•This is the first multicolour analysis of the binary system V658 Lyr.•Using the W-D code we found that it is an A-Subtype W UMa system.•V658 Lyr is an solar-type system and show a decreasing ...period.•It belong to the group of the deep, low mass-ratio (DLMR) systems.•The absolute dimensions of V658 Lyr are estimated and discussed.
We present the first light curve analysis of the eclipsing binary V658 Lyr.
B, V and Ic photometric observations made from 2014 to 2017 of this W UMa-type binary star are collected, the complete light curves were obtained in 2015 (4 nights) and 2016 (11 nights) and are used for a detailed photometric analysis to determine orbital and physical parameters using the Wilson-Devinney code.
The results obtained indicates that V658 Lyr is an A-type overcontact binary system with both components of spectral type (G2 + G4).
Based on our 17 ToM the short orbital period of the eclipsing binary was confirmed and revised to P = 0.3302577 days.
The orbital period was found to show a cyclic variations and a decrease rate of dP/dt = −2.97×10−7 days yr−1, which can be interpreted as a mass transfer from the more massive component to the less massive one.
We have not found an asymmetry of the light curves.
The mass of the primary and secondary stars are calculated to be M1 = 1.18M⊙( ± 0.08) and M2 = 0.21M⊙( ± 0.01) indicating the primary to be underluminous for its mass and the secondary to be overluminous for its mass.
Microvessel density (MVD) represents a measure of angiogenesis and may be used as an indicator of neoplastic aggressiveness. Vascular endothelial growth factor (VEGF) plays a pivotal role as ...angiogenic promoter by stimulating endothelial cell proliferation and migration and enhancing vascular permeability. The aim of this study was to investigate MVD and VEGF expression in human pituitary adenomas and normal pituitary gland tissues by immunohistochemistry, and to correlate data with clinical characteristics. Fragments from 46 pituitary adenomas (18 non-functioning, 12 ACTH-secreting, 12 GH-secreting, 4 PRL-secreting) and 19 specimens of normal anterior pituitary gland obtained at surgery were evaluated. MVD in normal anterior pituitary was significantly higher than in tumors (69.2 +/- 28.5 vs 29.3 +/- 19.7; p < 0.0001). Within adenomas, no difference was found in MVD when different histotype, size, sex, age, rate of recurrence or medical pre-surgical treatment were considered. The degree of vascularity was somewhat related only to clinical invasiveness, as evaluated by pre-surgical MRI grading (grade 0 p < 0.05 vs grade 1 and vs grade 2). No statistically significant difference in VEGF expression was found between normal tissue and adenomas and among tumors of different histotype (p = 0.3978). Size, sex, age, rate of recurrence and medical pre-surgical treatment did not influence VEGF expression. No correlation was found between MVD and VEGF expression. In conclusion, MVD was reduced in pituitary adenomas with respect to normal gland. VEGF expression is however well preserved in adenomas and this might contribute to adequate tumoral vascular supply with complex mechanisms other than endothelial cells proliferation.
3D integration technologies for custom SiPM: From BSI to TSV interconnections Parellada-Monreal, L.; Acerbi, F.; Ficorella, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
April 2023, 2023-04-00, Letnik:
1049
Journal Article
Recenzirano
Progress in 3D interconnecting technologies paved the way for a new generation of Silicon Photomultipliers (SiPM) and Single Photon Avalanche Diode (SPAD): hybrid devices which combine the integrated ...functionalities of the digital SiPM with the high performance of custom technologies, like low noise and high detection efficiency. Recently, Fondazione Bruno Kessler (FBK) has been working on the implementation of recently developed 3D integration technologies, on SiPMs devices, to improve both performances and functionalities by creating backside-illuminated (BSI) devices and Through Silicon Vias (TSV) interconnections.
Two different technology platforms have been investigated: a BSI design for near-infrared (NIR) sensitive SiPMs and TSV interconnections for near- and vacuum-ultraviolet (NUV/VUV) sensitive detectors.
For NIR applications, electrical characterization of ultra-thin (about 10μm) SiPM wafers with a metal reflector on the frontside has shown an improved photon detection efficiency (PDE) when operated in BSI configuration compared with non-thinned front-side illuminated (FSI) devices, allowing at the same time full high-segmentation access to the SiPM output from the front-side.
Instead, for NUV/VUV applications, a FSI stacked approach is considered more suitable since the junction depth needs to be shallower. In this case, TSV interconnections using two different approaches (named Via-Mid and Via-Last) have been implemented allowing the placement of the contacts on the backside of the wafer.
•A first demonstrator of BSI SiPM for NIR light detection was developed at FBK.•SiPMs with thick epitaxial layer and metal reflector on top show the highest PDE.•Two fabrication process flows with TSV for VUV detection are proposed.•Via-Mid approach shows proper electrical isolation between the TSV and bulk-silicon.•TSV filling with a dielectric polymer has been demonstrated for Via-Last approach.
•We present the first multi-color light curve analysis of the eclipsing binary star NSVS 7051868.•The system belong to the A-subtype W Ursae Majoris systems.•A moderate degree of contact and a ...relatively large difference of temperature between the components is found.•NSVS 7051868 may be in a key evolutionary stage of the TRO theory.•Its position in the H-R diagram is showed and the physical parameter are estimated.
The first CCD photometric complete light curves of the eclipsing binary NSVS 7051868 were obtained during six nights in January 2016 in the B, V and Ic bands using the 0.25 m telescope of the Stazione Astronomica Betelgeuse in Magnago, Italy.
These observations confirm the short period (P = 0.517 days) variation found by Shaw and collaborators in their online list (http://www.physast.uga.edu/~jss/nsvs/) of periodic variable stars found in the Northern Sky Variability Survey.
The light curves were modelled using the Wilson–Devinney code and the elements obtained from this analysis are used to compute the physical parameters of the system in order to study its evolutionary status.
A grid of solutions for several fixed values of mass ratio was calculated.
A reasonable fit of the synthetic light curves of the data indicate that NSVS 7051868 is an A-subtype W Ursae Majoris contact binary system, with a low mass ratio of q = 0.22, a degree of contact factor f = 35.5% and inclination i = 85°. Our light curves shows a time of constant light in the secondary eclipse of approximately 0.1 in phase. The light curve solution reveals a component temperature difference of about 700 K. Both the value of the fill-out factor and the temperature difference suggests that NSVS 7051868 is a system in a key evolutionary stage of the Thermal Relaxation Oscillation theory.
The distance to NSVS 7051868 was calculated as 180 pc from this analysis, taking into account interstellar extinction.
Purpose
To report experience on the use of self-closing nitinol U-Clips for different types of intracranial arterial microanastomosis.
Methods
We treated 7 patients (3 females and 4 males, age ...ranging from 25 to 68 yo) admitted from November 2005 to January 2008 to the Neurological Institute C. Besta of Milan. One patient had cerebral hypoperfusion and the others a complex intracranial aneurysm. In each patient a bypass procedure was completed by using self-closing Nitinol U-Clips for intracranial arterial microanastomoses.
Results
The total time of temporary occlusion was 15.71 ± 4.386 min. Bypass patency was confirmed intraoperatively by near-infrared indocyanine green videoangiography and microdoppler in each patient. No spasm of the graft was encountered and immediate post-operative bypass patency was confirmed in 6/7 patients. The graft thrombosed in 1 patient with antiphospholipid syndrome. 1 patient died from a massive Subarachnoid Hemorrhage due to rupture of an aneurysm while waiting for an endovascular procedure. In the 5 patients at the last follow-up, long-term patency of the bypass was confirmed and no neurological deficits occurred related to the procedure.
Conclusion
This is the first report of the use of U-Clips for intracranial microanastomosis. Our data indicated that it is a safe technique, reduces the time taken to perform an anastomosis and the risk of an ischemic complication. Further studies of the longer-term patency of bypass as performed with U-Clips are required.
In this work, we propose a new analog SiPM structure, characterized by the Passive Quenching Active Recharge operation of the microcells. The structure is obtained by including a MOSFET transistor ...close to each cell. The transistor is built without any changes to the standard SiPM micro-fabrication process and it does not significantly reduce the fill-factor of the device. We operated this detector in a periodic pulsed reset mode. Potential advantages of this approach are: reduction of the effective Dark Count Rate, strong suppression of the afterpulsing, very short pulse duration, lower fabrication cost. In this paper, we provide a preliminary characterization of the first 1×1 mm 2 prototype of the structure, with 50×50 μm 2 cells, fabricated at FBK. The measured duration of the single-cell response is 3.4 ns FWHM. Using a pulsed LED source, we were able to measure a very good photon counting resolution at a level of 18 detected photons and more, thanks to the absence of after pulses.
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