Monolithic crystals for PET devices: Optical coupling optimization González, A.J.; Peiró, A.; Conde, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
731
Journal Article
Recenzirano
Odprti dostop
In this work we present a method to efficiently collect scintillation light when using monolithic scintillator crystals. The acceptance angle of the scintillation light has been reduced by means of ...optical devices reducing the border effect which typically affects continuous crystals. We have applied this procedure on gamma detectors for PET systems using both position sensitive PMTs and arrays of SiPMs. In the case of using SiPMs, this approach also helps to reduce the photosensor active area.
We evaluated the method using PMTs with a variety of different crystals with thicknesses ranging from 10 to 24mm. We found that our design allows the use of crystal blocks with a thickness of up to 18mm without degrading the spatial resolution caused by edge effects and without a significant detriment to the energy resolution. These results were compared with simulated data. The first results of monolithic LYSO crystals coupled to an array of 256 SiPMs by means of individual optical light guides are also presented.
•Acceptance angle reduction decreases border effect in continuous crystals.•Experimental measurements with PMTs correlate well with simulated data.•Optical devices called faceplates serve to control the scintillation light angle.•Simulation on the light propagation for SiPMs requires exhaustive modeling.
Does age affect endometrial gene expression?
Using unsupervised artificial intelligence methods, we report for the first time that endometrial gene expression changes from 35 years of age in women.
...Female fertility declines with age, largely attributed to declining oocyte quality and ovarian reserve. Combined with other evidence, a longstanding paradigm holds that age does not affect the endometrial function and age has not been controlled for properly in endometrial studies.
A retrospective in silico analysis was performed of endometrial transcriptomic data from the Gene Expression Omnibus (GEO) sample repository for 27 women of different ages. Results were validated in an independent gene expression dataset of 20 endometrial samples from women aged 23-43 years.
A systematic search was performed in GEO from October 2016 to January 2019 to identify transcriptomic studies involving women of different ages. Included samples were from norm-ovulatory, women of reproductive age (23-49 years) with regular menstrual cycles who were free of endometriosis and used as controls in a previous endometrial study. We used raw gene expression data and metadata from these samples to investigate the effect of age on endometrial gene expression. Files were downloaded, pre-processed and explored for potential confounding variables and outliers. Artificial intelligence methods were applied to define age groups, and differential expression and functional analyses were applied to demonstrate and understand the effect of age on gene expression at the molecular level. Functional results were validated in an independent gene expression dataset of 20 endometrial samples from women aged 23-43 years.
Analysis of the initially retrieved endometrial datasets revealed the age of participants was not available (33.33%) or traceable (43.33%) in most studies. However, one study was suitable for age analysis (GSE4888, n = 27, 23-49 years). Samples showed different transcriptomic profiles according to age, beginning at 35 years. A total of 5778 differentially expressed genes and 27 significantly altered endometrial functions (false discovery rate (FDR) < 0.05) were associated with endometrial gene expression changes related to age. Interestingly, 81.48% of affected functions were related to up-regulation of ciliary processes, with 91 genes involved in cilia motility and ciliogenesis. Other functions included dysregulation of the vascular endothelial growth factor signalling pathway and inhibition of epithelial proliferation triggered by 37 genes involved in cell cycle arrest, angiogenesis, insulin signalling and telomere protection. These findings were validated in an independent dataset using a non-targeted approach; 20 up-regulated ciliary processes (FDR < 0.02) and 6 down-regulated functions related to cell cycle arrest were identified as affected by age, among other hallmarks of ageing such as DNA repair inhibition or sugar metabolism (FDR < 0.05).
Data underlying this article are available in GEO, IDs: GSE4888 (main dataset) and GSE102131 (validation dataset).
This study is limited in size, as are most studies of endometrial transcriptomics where whole-transcriptome analysis considers nearly 22 000 variables in a relatively small population. Yet, our study includes a main sample set and subsequent validation set that enhances reproducibility of our results and provides reasonable evidence for concluding that age affects endometrial gene expression. A larger study prospectively controlling for patient characteristics is needed to accurately describe changes related to age, with a higher sample size and across a wide age range. Additional studies also are necessary to determine the endometrial ageing contribution to infertility for ultimate translation to a clinical setting.
Our findings support an influence of age on the endometrium in a genome-wide functional approach, breaking the endometrial ageing paradigm in human reproduction. To our knowledge, this work is the first to identify, using a genome-wide functional non-targeted approach, ciliary processes as the primary dysregulated function associated with maternal age. These results should guide the research community to control for age as a potential confounding variable in endometrial gene expression studies and to consider endometrial ageing in further studies as a potential cause of infertility in the clinical setting. The reported functional dysregulations could contribute to diminished embryo implantation with age and further studies will demonstrate if such dysregulation underlies some cases of implantation failure. Additionally, the discovery of these functional alterations could enable mechanistic studies, particularly around the age-related increase in uterine pathologies.
This research was funded by the Instituto de Salud Carlos III through Miguel Servet programme (CP20/00118) granted to Patricia Diaz-Gimeno (Spanish Government) co-funded by FEDER; and by IVI Foundation (1706-FIVI-041-PD). A.D.-P. (FPU/15/01398) and A.P.-L. (FPU18/01777) are granted by the pre-doctoral programme fellowship from the Ministry of Science, Innovation and Universities (Spanish Government). The authors do not have any competing interests to declare.
N/A.
Design of the PET–MR system for head imaging of the DREAM Project González, A.J.; Conde, P.; Hernández, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2013, Letnik:
702
Journal Article
Recenzirano
Odprti dostop
In this paper we describe the overall design of a PET–MR system for head imaging within the framework of the DREAM Project as well as the first detector module tests. The PET system design consists ...of 4 rings of 16 detector modules each and it is expected to be integrated in a head dedicated radio frequency coil of an MR scanner.
The PET modules are based on monolithic LYSO crystals coupled by means of optical devices to an array of 256 Silicon Photomultipliers. These types of crystals allow to preserve the scintillation light distribution and, thus, to recover the exact photon impact position with the proper characterization of such a distribution. Every module contains 4 Application Specific Integrated Circuits (ASICs) which return detailed information of several light statistical momenta. The preliminary tests carried out on this design and controlled by means of ASICs have shown promising results towards the suitability of hybrid PET–MR systems.
The analysis of sperm DNA fragmentation has become a new marker to predict male infertility, and many techniques have been developed. The sperm Comet assay offers the possibility of differentiating ...single- and double-stranded DNA (ssDNA and dsDNA) breaks, which could have different effects on fertility. The objective of this study was to perform a descriptive characterization of different groups of patients, such as those with asthenoteratozoospermic (ATZ) with or without varicocele, oligoasthenoteratozoospermic (OATZ) or balanced chromosome rearrangements, as compared with fertile donors. The Comet assay was used to investigate sperm samples for ssDNA and dsDNA breaks.
METHODS AND RESULTS
The analysis of alkaline and neutral Comet assays in different groups of patients showed different sperm DNA damage profiles. Most fertile donors presented low values for ssDNA and dsDNA fragmentation (low-equivalent Comet profile), which would be the best prognosis for achieving a pregnancy. OATZ, ATZ and ATZ with varicocele presented high percentages of ssDNA and dsDNA fragmentation (high-equivalent Comet assay profile), ATZ with varicocele being associated with the worst prognosis, due to higher levels of DNA fragmentation. Rearranged chromosome carriers display a very high variability and, interestingly, two different profiles were seen: a high-equivalent Comet assay profile, which could be compatible with a bad prognosis, and a non-equivalent Comet assay profile, which has also been found in three fertile donors.
CONCLUSIONS
Comet assay profiles, applied to different clinical groups, may be useful for determining prognosis in cases of male infertility.
Background: Overexpression and functional mutations of p53 have been found in the synovial tissue (ST) of patients with rheumatoid arthritis (RA), but their clinical significance remains unclear. ...Objective: To analyse p53 expression in the ST of patients with RA and psoriatic arthritis (PsA) and its association with joint damage. Methods: Synovial biopsy specimens were obtained by arthroscopy in 45 patients (27 RA, 18 PsA). Radiographs of hands, feet, and the joint undergoing arthroscopy were obtained to evaluate the presence of erosive disease. Synovial cell populations were analysed using CD4, CD8, CD138, CD20, and CD68 monoclonal antibodies (mAbs). The p53 protein was determined by immunohistology using DO7 mAb in 34 patients (18 RA, 16 PsA). In 11 patients with early RA, the association between p53 and 1 year progression of radiographic damage was analysed using the Larsen-Scott method. Results: The p53 protein was detected in 16/18 (89%) patients with RA and in 9/16 (56%) patients with PsA, but its expression in RA was significantly higher than in PsA. In RA, p53 expression was significantly associated with erosive disease, and its scores were higher in patients with radiological progression. CD68 expression was also associated with erosions and radiological progression in RA. No association was found between either p53 or CD68 and erosive disease in PsA. Conclusions: These results suggest that p53 ST overexpression and association with joint damage is characteristic of RA rather than PsA, and that p53 ST expression might be a prognostic marker of joint damage in RA.
To describe our series of patients with giant cell tumour of bone with a long-term follow-up to show the results obtained with our treatment protocol.
A total of 97 histologically confirmed giant ...cell tumour of bone were treated in our center between 1982 and 2009. The mean follow-up period was 12 years (2-27 years). The treatment received was determined by the radiological grade based on the Campanacci classification. The series consisted of 53 women (54.6%) and 44 men (54.4%) with a median age of 34.16 years (15-71 years). The data collected was focused on the clinical presentation, location, phase, extension, recurrences, and complications.
The treatment most used in Campanacci grades i and ii was intralesional excision with high velocity drilling and filling with a graft. In grades iii that could not be treated with the aforementioned method, it was decided to perform en bloc resection. An overall recurrence rate of around 25.8% was observed. Seven cases (7.2%) presented with a recurrence of the malignancy. The death rate at the end of follow-up was 2.1% (2 cases).
Curettage with a high-velocity drill and a bone graft in giant cell tumour of bone Campanacci grades i and ii obtain good results after long-term follow-up. Some grade iii giant cell tumour of bone that cannot be treated with this therapeutic option require en bloc resection and reconstruction.
Crystalline TiO2 films have been deposited on several substrates (glass, F-doped SnO2-covered glass, and silicon wafers) by a drain-coating method from a colloidal anatase aqueous solution. The ...process is performed at low-temperature, 333 K, in open atmosphere. The colloidal TiO2 consists on anatase nanoparticles of about 9 × 5 nm size, stabilized by tetrabutylammonium cations (TBA+). This colloid has also been obtained under mild conditions (i.e., low temperature and ambient pressure) by hydrolysis of tetraisopropyl orthotitanate (TIP) in the presence of (TBA)OH and subsequent treatment by microwave radiation to enhance crystallization. Different film thicknesses have been obtained by consecutive deposition processes. Titania films thus obtained were transparent and showed good adherence. FT-IR analysis of the films reveal that TBA cations were not trapped in the film during the deposition process. No further thermal posttreatment was required to eliminate organics from the films or to induce titania crystallization. The photocatalytic activity of as-deposited titania has been assessed by the photodegradation of salicylic acid in aqueous solution under aerated conditions.
PDF
