93 research outputs found
Data Processing Engine (DPE): Data Analysis Tool for Particle Tracking and Mixed Radiation Field Characterization with Pixel Detectors Timepix
Hybrid semiconductor pixelated detectors from the Timepix family are advanced
detectors for online particle tracking, offering energy measurement and precise
time stamping capabilities for particles of various types and energies. This
inherent capability makes them highly suitable for various applications,
including imaging, medical fields such as radiotherapy and particle therapy,
space-based applications aboard satellites and the International Space Station,
and industrial applications. The data generated by these detectors is complex,
necessitating the development and deployment of various analytical techniques
to extract essential information. For this purpose, and to aid the Timepix user
community, it was designed and developed the "Data Processing Engine" (DPE) as
an advanced tool for data processing designed explicitly for Timepix detectors.
The functionality of the DPE is structured into three distinct processing
levels: i) Pre-processing: This phase involves clusterization and the
application of necessary calibrations and corrections. ii) Processing: This
stage includes particle classification, employing machine learning algorithms,
and the recognition of radiation fields. iii) Post-processing: Involves various
analyses, such as directional analysis, coincidence analysis, frame analysis,
Compton directional analysis, and the generation of physics products, are
performed. The core of the DPE is supported by an extensive experimental
database containing calibrations and referential radiation fields of typical
environments, including protons, ions, electrons, gamma rays and X-rays, as
well as thermal and fast neutrons. To enhance accessibility, the DPE is
implemented into various user interface platforms such as a command-line tool,
an application programming interface, and as a graphical user interface in the
form of a web portal.Comment: 9 pages, proceedings IWORI
Proton Radiography for a Small-Animal Irradiation Platform Based on a Miniaturized Timepix Detector
Pre-treatment proton radiography and computed tomography can improve precision of proton therapy. A compact imaging setup for small-animal proton radiography, based on a miniaturized Timepix detector is presented along with results from proof-of-concept experiments. The MiniPIX detector was placed behind a µ-CT calibration phantom with 10 different tissue-equivalent inserts. The intensity of the 70 MeV proton beam was adjusted such that pixel signal clusters from individual protons on the detector could be resolved. Analysis and event filtering on various cluster properties were used to suppress unwanted events. The energy deposition of the selected clusters was converted to water-equivalent thickness (WET) of the traversed material using a conversion curve based on Monte Carlo simulations and measured clusters of protons after traversing PMMA slabs of known thickness. Despite a systematic underestimation of up to 3%, retrieved WET values are in good agreement with ground truth values from literature. The achieved spatial resolution ranges from 0.3 to 0.7 mm for phantom-detector-distances of 1 to 5 cm. Applicability to living animals is currently limited by the relatively long acquisition time of up to 20 minutes per radiography. This obstacle can however be overcome with the latest detector generation Timepix3, allowing to handle higher particle rates and thus requiring shorter irradiation times
Covalent Graft of Lipopeptides and Peptide Dendrimers to Cellulose Fibers
Introduction: Bacterial proliferation in health environments may lead to the development of specific pathologies, but can be highly dangerous under particular conditions, such as during chemotherapy. To limit the spread of infections, it is helpful to use gauzes and clothing containing antibacterial agents. As cotton tissues are widespread in health care environments, in this contribution we report the preparation of cellulose fibers characterized by the covalent attachment of lipopeptides as possible antimicrobial agents. Aim: To covalently link peptides to cotton samples and characterize them. Peptides are expected to preserve the features of the fabrics even after repeated washing and use. Peptides are well tolerated by the human body and do not induce resistance in bacteria. Materials and Methods: A commercially available cotton tissue (specific weight of 150 g/m2, 30 Tex yarn fineness, fabric density of 270/230 threads/10 cm in the warp and weft) was washed with alkali and bleached and died. A piece of this tissue was accurately weighed, washed with methanol (MeOH) and N,N-dimethylformamide (DMF), and air-dried. Upon incubation with epibromohydrin, followed by treatment with Fmoc-NH-CH2CH2-NH2 and Fmoc removal, the peptides were synthesized by incorporating one amino acid at a time, beginning with the formation of an amide bond with the free NH2 of 1,2\u2013diaminoethane. We also linked to the fibers a few peptide dendrimers, because the mechanism of action of these peptides often requires the formation of clusters. We prepared and characterized seven peptide-cotton samples. Results: The new peptide-cotton conjugates were characterized by means of FT-IR spectroscopy and X-ray Photoelectron Spectroscopy (XPS). This latter technique allows for discriminating among different amino acids and thus different peptide-cotton samples. Some samples maintain a pretty good whiteness degree even after peptide functionalization. Interestingly, these samples also display encouraging activities against a Gram positive strain. Conclusions: Potentially antimicrobial lipopeptides can be covalently linked to cotton fabrics, step-by-step. It is also possible to build on the cotton Lys-based dendrimers. XPS is a useful technique to discriminate among different types of nitrogen. Two samples displaying some antibacterial potency did also preserve their whiteness index
Measurement of the time structure of FLASH beams using prompt gamma rays and secondary neutrons as surrogates
We aim to investigate the feasibility of online monitoring of irradiation
time (IRT) and scan time for FLASH radiotherapy using a pixelated semiconductor
detector. Measurements of the time structure of FLASH irradiations were
performed using fast, pixelated spectral detectors, AdvaPIX-TPX3 and
Minipix-TPX3. The latter has a fraction of its sensor coated with a neutron
sensitive material. With little or no dead time and an ability to resolve
events that are closely spaced in time (tens of ns), both detectors can
accurately determine IRTs as long as pile-ups are avoided. To avoid pile-ups,
we placed the detectors beyond the Bragg peak or at a large scattering angle.
We acquired prompt gamma rays and secondary neutrons and calculated IRTs based
on timestamps of the first (beam-on) and the last (beam-off) charged species.
We also measured scan times in x, y, and diagonal directions. We performed
these measurements for a single spot, a small animal field, a patient field,
and a ridge filter optimized field to demonstrate in vivo online monitoring of
IRT. All measurements were compared to vendor log files. Differences between
measurements and log files for a single spot, a small animal field, and a
patient field were within 1%, 0.3% and 1%, respectively. In vivo monitoring of
IRTs was accurate within 0.1% for AdvaPIX-TPX3 and within 6.1% for
Minipix-TPX3. The scan times in x, y, and diagonal directions were 4.0, 3.4,
and 4.0 ms, respectively. Overall, the AdvaPIX-TPX3 can measure FLASH IRTs
within 1% accuracy, indicating that prompt gamma rays are a good surrogate for
primary protons. The Minipix-TPX3 showed a higher discrepancy, suggesting a
need for further investigation. The scan times (3.4 \pm 0.05 ms) in the 60-mm
distance of y-direction were less than (4.0 \pm 0.06 ms) in the 24-mm distance
of x-direction, confirming the much faster scanning speed of the Y magnets than
that of X.Comment: 11 pages, 5 figure
Probiotics and red fruit extracts with bioactive properties for innovative dietary supplements for human health.
Alimenti funzionali e nutraceutici per la salute. A cura delle Piattaforme Tematiche di Ateneo su "Alimenti e Nutrizione" e "Salute Umana ed Animale
Silicon Carbide Timepix3 detector for quantum-imaging detection and spectral tracking of charged particles in wide range of energy and field-of-view
The hybrid architecture of the Timepix (TPX) family of detectors enables the
use of different semiconductor sensors, most commonly silicon (Si), as well as
high-density materials such as Cadmium Telluride (CdTe) or Gallium Arsenide
(GaAs). For this purpose, we explore the potential of a silicon carbide (SiC)
sensor bump-bonded on a Timepix3 detector as a radiation imaging and particle
tracking detector. SiC stands as a radiation-hard material also with the
ability to operate at elevated temperatures up to several hundreds of degrees
Celsius. As a result, this sensor material is more suitable for radiation harsh
environments compared to conventional e.g., Si sensors. In this work, we
evaluate the response for precise radiation spectrometry and high-resolution
particle tracking of newly developed SiC Timepix3 detector which is built and
operated as a compact radiation camera MiniPIX-Timepix3 with integrated readout
electronics. Calibration measurements were conducted with mono-energetic proton
beams with energies of 13, 22, and 31 MeV at the U-120M cyclotron at the
Nuclear Physics Institute Czech Academy of Science (NPI CAS), Prague, as well
as 100 and 226 MeV at the Proton Therapy Center Czech (PTC) in Prague.
High-resolution pattern recognition analysis and single-particle spectral
tracking are used for detailed inspection and understanding of the sensor
response. Results include distributions of deposited energy and linear energy
transfer (LET) spectra. The spatial uniformity of the pixelated detector
response is examined in terms of homogeneously distributed deposited energy.Comment: 9 pages, proceedings iWoRi
Determinazione del contenuto totale di polifenoli e valutazione in vitro dell'attività antiossidante, antimicrobica e prebiotica di estratti vegetali
Razionale dello studio. I polifenoli sono componenti essenziali della frutta con elevate attività biologiche (antiossidante, antinfiammatoria e antimicrobica) e proprietà salutari.
Metodi. ll contenuto totale di antociani, di fenoli e di flavonoidi è stato determinato in estratti di prugne, uva e bacche di sambuco utilizzando rispettivamente i metodi del pH differenziale, Folin-Ciocalteu e colorimetrico. lnoltre, è stata valutata l'attività antiossidante e quella inibente o stimolante degli estratti su microrganismi patogeni e probiotici (Synbiotec Srl).
Risultati. Lo studio ha rilevato un alto contenuto di antociani (355,4+51 1,7mg/l) negli estratti della buccia e polpa delle bacche di sambuco e della buccia d'uva. ll contenuto totale di flavonoidi e fenoli risulta più elevato nell'estratto della buccia delle bacche di sambuco (66,8 e 125,6p9/ml). lnoltre, quest'ultimo e l'estratto d'uva mostrano un'attività antiossidante del 90% di inibizione di DPPH. Tutti gli estratti inibiscono significativamente i patogeni testati (zona inibizione tra 7,5 e 19,3mm), dati confermati dai valori delle MlC, mentre non hanno attività inibente sui ceppi probiotici, ma ne stimolano la crescita.
Conclusioni. Gli estratti testati hanno una concentrazione di polifenoli, in particolare antociani, tale da poter essere considerati efficaci per la salute. Per la loro attività antiossidante, antimicrobica e prebiotica questi estratti vegetali possono essere considerati componenti bioattivi utili per la produzione di nuovi alimenti funzionali e prodotti nutraceutici benefici per la salute
Genetic landscape of 6089 inherited retinal dystrophies affected cases in Spain and their therapeutic and extended epidemiological implications
Inherited retinal diseases (IRDs), defined by dysfunction or progressive loss of photoreceptors, are disorders characterized by elevated heterogeneity, both at the clinical and genetic levels. Our main goal was to address the genetic landscape of IRD in the largest cohort of Spanish patients reported to date. A retrospective hospital-based cross-sectional study was carried out on 6089 IRD affected individuals (from 4403 unrelated families), referred for genetic testing from all the Spanish autonomous communities. Clinical, demographic and familiar data were collected from each patient, including family pedigree, age of appearance of visual symptoms, presence of any systemic findings and geographical origin. Genetic studies were performed to the 3951 families with available DNA using different molecular techniques. Overall, 53.2% (2100/3951) of the studied families were genetically characterized, and 1549 different likely causative variants in 142 genes were identified. The most common phenotype encountered is retinitis pigmentosa (RP) (55.6% of families, 2447/4403). The most recurrently mutated genes were PRPH2, ABCA4 and RS1 in autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) NON-RP cases, respectively; RHO, USH2A and RPGR in AD, AR and XL for non-syndromic RP; and USH2A and MYO7A in syndromic IRD. Pathogenic variants c.3386G > T (p.Arg1129Leu) in ABCA4 and c.2276G > T (p.Cys759Phe) in USH2A were the most frequent variants identified. Our study provides the general landscape for IRD in Spain, reporting the largest cohort ever presented. Our results have important implications for genetic diagnosis, counselling and new therapeutic strategies to both the Spanish population and other related populations.This work was supported by the Instituto de Salud Carlos III (ISCIII) of the Spanish Ministry of Health (FIS; PI16/00425 and PI19/00321), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER, 06/07/0036), IIS-FJD BioBank (PT13/0010/0012), Comunidad de Madrid (CAM, RAREGenomics Project, B2017/BMD-3721), European Regional Development Fund (FEDER), the Organización Nacional de Ciegos Españoles (ONCE), Fundación Ramón Areces, Fundación Conchita Rábago and the University Chair UAM-IIS-FJD of Genomic Medicine. Irene Perea-Romero is supported by a PhD fellowship from the predoctoral Program from ISCIII (FI17/00192). Ionut F. Iancu is supported by a grant from the Comunidad de Madrid (CAM, PEJ-2017-AI/BMD7256). Marta del Pozo-Valero is supported by a PhD grant from the Fundación Conchita Rábago. Berta Almoguera is supported by a Juan Rodes program from ISCIII (JR17/00020). Pablo Minguez is supported by a Miguel Servet program from ISCIII (CP16/00116). Marta Corton is supported by a Miguel Servet program from ISCIII (CPII17/00006). The funders played no role in study design, data collection, data analysis, manuscript preparation and/or publication decisions
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