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Introduction. The Beliefs about Medicines Questionnaire (BMQ) allows the assessment of cognitive representations encompassing patients' medication beliefs about taking medication for their disease in different cultures. Objective. To determine the construct validity and reliability of the BMQ questionnaire adapted to Colombian hypertensive patients. Materials and methods. An instrumental psychometric study was carried out in a sample of 238 hypertensive patients with an average age of 65 years (SD= 11.4), with a predominance of women (70%). Construct validity was assessed by exploratory and confirmatory factor analysis. Reliability was calculated using Cronbach's alpha coefficient method. Results. A reduced version of 16 items was obtained; in the BMQ-General section the 7 items were grouped into two factors that explained 64% of the common variance and good fit (χ²= 61.46; gl = 13; p = 0.000; CFI = 0.917; NNFI = 0.89; CFI=0.917; SRMR=0.054; RMSEA = 0.125; IC 90% [0,10, 0,16]). In the BMQ-Specific the 9 items grouped into two factors explained 63.17% of the common variance with an acceptable fit (χ² = 122.4; gl = 26; p = 0.000; CFI = 0.88; NNFI = 0.84; CFI=0.88; SRMR=0.106; RMSEA = 0.125; IC 90% [0.10, 0.15]). The Cronbach's alpha reliability for the BMQ-General and Specific was 0.82 and 0.78, respectively. Discussion and conclusions. The version of the BMQ adapted to Colombian hypertensive patients has adequate psychometric characteristics and its use is recommended in research. [ABSTRACT FROM AUTHOR]

In 2011, with the approval of the Economic and Social Policy Guidelines at the VI Congress of the Communist Party of Cuba, the creation of non-agro livestock cooperatives was promoted. In the province of Granma, in 2014, the first non-agro livestock cooperative "La Croquetera" was founded with the social purpose of providing gastronomic services. The cooperative sector in the province plays a fundamental role in satisfying the needs of the population. However, there are limitations that hinder and slow down the integral development of the cooperatives; for this reason, the objective of the research is to diagnose the main factors that limit the socioeconomic management of the non-agro livestock cooperative "La Croquetera". The theoretical method of high generalization used is the dialectical-materialistic one. As for the empirical methods, participant observation, survey and interview were used; the cooperative mirror instrument of the World Food Program was also used. As general results of the research, it was found that, among the factors limiting cooperative management, there is the lack of knowledge of cooperative principles, organizational problems and deficiency in contracts. [ABSTRACT FROM AUTHOR]

The public administrator has the responsibility to represent the state is a person with knowledge in political science that focuses its work on the State and the government. Using the economic, legal and social sciences. The combination of all these specialties expands the positions that can occupy within public bodies. Starting from this criterion it is necessary to create professionals in Public Administration, which can be in charge of a public management focused on the satisfaction of the individual and their needs, through organizations that function as a whole and fostering a new approach of the Public Administration, which in the doctrine has been called public management. Ecuador has tried to implement several trends for a public administration in different policies which have been considered for the curricular design of a degree in Public Administration. The objective of this work is to base the creation of a new career from a curricular perspective, demonstrating the tendencies of public administration related to the promotion and application of non-discriminatory laws and policies in favor of sustainable development, aspects that have been taken as a source and fundamentals of the curricular design of this university career. [ABSTRACT FROM AUTHOR]

Introduction. In Colombia, the General Education Law gave Educational Institutions the authority to organize their academic curricula according to their corresponding Educational Projects. Based on this institutional autonomy, some educational institutions have divided the area of mathematics into subjects such as statistics and geometry; also they have allocated a weekly time to each one of these subjects. In contrast, other institutions organize the area of mathematics by themes developed at specific times during the school year. In this sense, knowing the effects that one or another allocation could have on educational processes represents an interest for research and for teachers and educational institutions. Objective. Determine the effect that the allocation of teaching hours spent on the statistics subject could have on student performance on the Saber 11th Test in public educational institutions from Medellín- Colombia. Materials and Method. Data were extracted from the Saber 11-test results. A linear model was adjusted with mixed effects. Results. After controlling for the institution effect, it was found that some student-specific variables do impact the results in mathematics. However, allocation of teaching hours spent on statistics is not a significant factor. Conclusions. Time allocation and teaching hours spent on a statistics course do not have automatic or immediate impact on student performance. Every institution should consider strategies to promote student competencies according to their economic and social conditions. [ABSTRACT FROM AUTHOR]

Early diagnosis and therapy increasingly operate at the cellular, molecular, or even at the genetic level. As diagnostic techniques transition from the systems to the molecular level, the role of multimodality molecular imaging becomes increasingly important. Positron emission tomography (PET) and magnetic resonance imaging (MRI) are powerful techniques for in vivo molecular imaging. The inability of PET to provide anatomical information is a major limitation of standalone PET systems. Combining PET and CT proved to be clinically relevant and successfully reduced this limitation by providing the anatomical information required for localization of metabolic abnormalities. However, this technology still lacks the excellent soft-tissue contrast provided by MRI. Standalone MRI systems reveal structure and function but cannot provide insight into the physiology and/or the pathology at the molecular level. The combination of PET and MRI, enabling truly simultaneous acquisition, bridges the gap between molecular and systems diagnosis. MRI and PET offer richly complementary functionality and sensitivity; fusion into a combined system offering simultaneous acquisition will capitalize the strengths of each, providing a hybrid technology that is greatly superior to the sum of its parts. A combined PET/MRI system provides both the anatomical and structural description of MRI simultaneously with the quantitative capabilities of PET. In addition, such a system would allow exploiting the power of MR spectroscopy (MRS) to measure the regional biochemical content and to assess the metabolic status or the presence of neoplasia and other diseases in specific tissue areas. This paper briefly summarizes state-of-the-art developments and latest advances in dedicated hybrid PET/MRI instrumentation. Future prospects and potential clinical applications of this technology will also be discussed. [ABSTRACT FROM AUTHOR]

Abstract: Background: The C-allele of rs13266634 located in SLC30A8 (ZNT8) has been strongly associated with decreased insulin release and with type 2 diabetes (T2D) susceptibility in some but not all studies. To shed further light on this issue, we performed a meta-analysis of the association between rs13266634 and T2D in different ethnic groups and assessed the relationships between SLC30A8 genotypes and some properties of isolated human islets. Methods: From 32 original articles, a total of 77,234 control individuals and 44,945 subjects with T2D were studied in meta-analysis. To assess the relationships between SLC30A8 genotype and islet cell phenotype, insulin secretion in response to glucose, glucose plus arginine and glucose plus glibenclamide was determined in pancreatic islets isolated from 82 multiorgan donors genotyped for the rs13266634 polymorphism. Quantitative expression of SLC30A8, Insulin and Glucagon mRNA was also measured. Results: Overall, each SLC30A8 risk allele was associated with a 14% increased risk for T2D (P =2.78×10−34). The population risk of T2D attributable to this polymorphism was estimated at 9.5% in Europeans and 8.1% in East Asians. Basal and stimulated insulin secretion from human islets as well as islet expressions of SLC30A8, Insulin and Glucagon were not affected by the presence of the polymorphism. However, SLC30A8 expression was positively correlated with Insulin (r =0.75, P =6.43×10−6) and Glucagon (r: 0.70, P =4.89×10−5) levels. Conclusions: The SLC30A8 rs13266634 polymorphism is among the most confirmed genetic markers of T2D in Europeans and East Asians. In isolated human islets, the risk C-allele does not affect ex-vivo insulin secretion and SLC30A8 expression, which is correlated with that of insulin and glucagon. [Copyright &y& Elsevier]

Abstract: A wide library of 3,7,8,8a-tetrahydro-2H-thiazolo[3,2-a]pyridines has been prepared by simple heating in acetonitrile of β-enaminonitriles, α,β-unsaturated aldehydes and 2-aminothiol hydrochlorides. Chemical yields depend on the nature, hindrance, and position of the substituents. The scope, limitations, and stereocontrol associated to this three-component reaction have been studied in detail. In general, the diastereoinduction observed in the three new stereogenic centers generated in the pro-chiral α,β-unsaturated aldehyde is low. [Copyright &y& Elsevier]

Objective. Describe the degree of relationship between family functioning and the level of anxiety in adult patients with chronic disease in a health institution at the second level. Methodology. The study design was descriptive, cross correlation, was performed on a sample of 97 patients and an equal number of families, the first ones were selected with a potential analysis, covering the following inclusion criteria: adult- oriented patients about the services and outpatient consultation of an institution at second level of care. We used a sociodemographic card, the scale of effective family functioning of Friedemann (E-EFF) and the scale of Spielberger trait-anxiety, the latter with an internal consistency of .83 and .75, respectively, as determined by Alpha Cronbach. Data were analyzed using descriptive and inferential statistics. Results. The age group that prevailed in the family was from 33 to 47 years, a mean of 45.73, and in the patients, was the group of 60 to 70 years, an mean of 65.05; in both groups stressed the female gender. 56% of patients had diabetes mellitus type 2. As for the indices, trait-anxiety had a mean of 51 (10.7) in the EFF-E was 84 (11.5). Therefore, there was moderate level of anxiety in 92% of the patients and 91% integrating a functional family. The Spearman correlation showed no significant association between the two variables of the study (rho = -. 094, p = .362). Conclusion. The four subscales of the E-half EFF obtained significant values ranging from 77.0 to 92.0. The latter value is equivalent to the subscale of consistency, according to Friedemann, guide to family unity and membership also allows positive emotional bonds. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the performance evaluation of the small animal scanner YAP-(S)PET, both in PET and SPECT modalities following preliminary NEMA standards for small animal PET. Data are taken with a new version of the scanner that is installed at the IFC-CNR in Pisa (Italy) within the framework of the Center of Excellence AmbiSEN of the University of Pisa. This paper also reports some preliminary SPECT applications in neuroscience using 123I-FP-CIT (DaTSCAN). [Copyright &y& Elsevier]

Summary: At the University of Pisa we are building a PEM prototype, the YAP–PEM camera, consisting of two opposite 6×6×3cm3 detector heads of 30×30 YAP:Ce finger crystals, 2×2×30mm3 each. The camera will be equipped with breast compressors. The acquisition will be stationary. Compared with a whole body PET scanner, a planar Positron Emission Mammography (PEM) camera allows a better, easier and more flexible positioning around the breast in the vicinity of the tumor: this increases the sensitivity and solid angle coverage, and reduces cost. To avoid software rejection of data during the reconstruction, resulting in a reduced sensitivity, we adopted a 3D-EM reconstruction which uses all of the collected Lines Of Response (LORs). This skips the PSF distortion given by data rebinning procedures and/or Fourier methods. The traditional 3D-EM reconstruction requires several times the computation of the LOR-voxel correlation matrix, or probability matrix {p ij }; therefore is highly time-consuming. We use the sparse and symmetry properties of the matrix {p ij } to perform fast 3D-EM reconstruction. Geometrically, a 3D grid of cubic voxels (FOV) is crossed by several divergent 3D line sets (LORs). The symmetries occur when tracing different LORs produces the same p ij value. Parallel LORs of different sets cross the FOV in the same way, and the repetition of p ij values depends on the ratio between the tube and voxel sizes. By optimizing this ratio, the occurrence of symmetries is increased. We identify a nucleus of symmetry of LORs: for each set of symmetrical LORs we choose just one LOR to be put in the nucleus, while the others lie outside. All of the possible p ij values are obtainable by tracking only the LORs of this nucleus. The coordinates of the voxels of all of the other LORs are given by means of simple translation rules. Before making the reconstruction, we trace the LORs of the nucleus to find the intersecting voxels, whose p ij values are computed and stored with their voxel coordinates on a hard disk. Only the non-zero p ij are considered and their computation is performed just once. During the reconstruction, the stored values are loaded and are available in the random access memory for all of the operations of normalization, backprojection and projection: these are now performed rapidly, because the application of the translation rules is much faster than the probability computations. We tested the algorithm on Monte Carlo data fully simulating the typical YAP–PEM clinical condition. The adopted algorithm gives an excellent positioning capability for hot spots in the camera FOV. To use all of the possible skew LORs in the FOV avoids the software rejection of collected data. Reconstructed images indicate that a 5mm diameter tumor of 37kBq/cm3, in an active breast with a 10:1 Tissue to Background ratio (T/B), with a 10min acquisition, for a head distance of 5cm, can be detected by the YAP–PEM with a SNR of 8.7±1.0. The obtained SNR values depend linearly on the tumor volume. The algorithm allows one to discriminate between two hot sources of 5.0mm diameter if they do not lie on the same axis. The YAP–PEM is now in the assembly stage. [Copyright &y& Elsevier]

Phenylketonuria is an inherited condition characterised by neurotoxic accumulation of phenylalanine (Phe). APHENITY assessed the efficacy and safety of orally administered synthetic sepiapterin in children and adults with phenylketonuria. APHENITY was a phase 3, randomised, double-blind, placebo-controlled study performed at 34 clinics, hospitals, and university sites in 13 countries. Individuals of all ages with a clinical diagnosis of phenylketonuria were eligible for inclusion if they had a blood Phe concentration of 360 μmol/L or higher at study entry, whereas individuals with hyperphenylalaninaemia due to pathogenic variants in GCH1, PTS, QDPR, SPR , and PCBD1 , consistent with a diagnosis of primary BH 4 deficiency, were excluded. Part 1 was a 14-day open-label assessment of blood Phe concentration response to sepiapterin. In part 2, sepiapterin-responsive participants were randomly assigned (1:1) by a web-response system based on a block randomisation schedule (permuted block size of 2 and 4) to 6 weeks of sepiapterin (forced-dose escalation: 20, 40, and 60 mg/kg per day per consecutive 2-week period) or placebo. The investigational drug and placebo were identical in their appearance and delivery. Dried blood samples were collected for analysis of Phe concentration on days –1, 1 (before dose was administered), 5, 10, 14, 19, 24, 28, 33, 38, and 42 in part 2, either in-clinic or at home. The primary endpoint for part 2, mean change from baseline in blood Phe after 6 weeks, was assessed in the primary analysis set of participants with at least a 30% reduction in blood Phe concentration in part 1, who took at least one dose in part 2. Safety was evaluated in all participants receiving at least one dose of treatment. The completed study is registered at EudraCT (2021-000474-29) and ClinicalTrials.gov (NCT05099640). APHENITY was conducted between Sept 30, 2021, and April 3, 2023. 187 people were assessed for eligibility, of whom 157 were enrolled. In part 1, 156 participants were assessed or evaluated, of whom 114 (73%) were sepiapterin-responsive (ie, ≥15% reduction in blood Phe from baseline). In part 2, 98 participants (49 in the placebo group and 49 in the sepiapterin group) were in the primary analysis set. There was a significant reduction of blood Phe concentration after 6 weeks of sepiapterin (–63%, SD 20) compared with placebo (1%, 29; least squares mean change –395·9 μmol/L, SE 33·8; p<0·0001). Treatment-emergent adverse events were reported in 33 (59%) of 56 participants who received sepiapterin and 18 (33%) of 54 participants who received placebo. Most treatment-emergent adverse events were mild gastrointestinal events (11 [20%] of 56 participants who received sepiapterin and ten [19%] of 54 participants who received placebo) that resolved quickly. There were no deaths and no serious or severe adverse events. Sepiapterin is a promising oral therapy for individuals with phenylketonuria, was well tolerated, and resulted in significant and clinically meaningful reductions in blood Phe concentration in participants with varying disease severity. PTC Therapeutics. [ABSTRACT FROM AUTHOR]

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been developed as an alternative transplant strategy for children with hematological disorders who do not have an HLA-matched donor. We report the analysis of the outcome for 18 consecutive pediatric patients with various hematological diseases, who underwent haplo-HSCT using a reduced-intensity conditioning regimen and CD3/CD19 depletion in an outpatient setting. Twelve of the 18 patients (66.6%) engrafted either transiently or definitively (9 patients engrafted with full donor chimerism and 3 with mixed chimerism). Six patients with acute lymphoblastic leukemia were disease-free between 2 and 35 months (median 25 months) post-HSCT. The overall survival was 33.3% with a median of 25 months (range 2-35). Our results suggest that haplo-HSCT can be a feasible therapeutic alternative for children who do not have a suitable family donor or available cord blood units. These results also demonstrate that it is possible to perform this regimen on an outpatient basis. [ABSTRACT FROM AUTHOR]

A prototype for Positron Emission Mammography, the YAP-PEM, is under development within a collaboration of the Italian Universities of Pisa, Ferrara, and Bologna. The aim is to detect breast lesions, with dimensions of 5 mm in diameter, and with a specific activity ratio of 10:1 between the cancer and breast tissue. The YAP-PEM is composed of two stationary detection heads of 6×6 cm2, composed of a matrix of 30×30 YAP:Ce finger crystals of 2×2×30 mm3 each. The EGSnrc Monte Carlo code has been used to simulate several characteristics of the prototype. A fast EM algorithm has been adapted to reconstruct all of the collected lines of flight, also at large incidence angles, by achieving 3D positioning capability of the lesion in the FOV. The role of the breast compression has been studied. The performed study shows that a 5 mm diameter tumor of 37 kBq/cm3 (1 μCi/cm3), embedded in active breast tissue with 10:1 tumor/background specific activity ratio, is detected in 10 min with a Signal-to-Noise Ratio of 8.7±1.0. Two hot lesions in the active breast phantom are clearly visible in the reconstructed image. [Copyright &y& Elsevier]

This review describes the properties of available and emerging radiation detector and read-out technologies and discusses how they may affect PET scanner performance. After a general introduction, there is a section in which the physical properties of several different detector scintillators are compared. This is followed by a discussion of recent advances in read-out electronics. Finally, the physical performance of the several commercial PET scanners is summarized. [ABSTRACT FROM AUTHOR]

Since the float-zone (FZ) silicon has lower contaminations and longer minority-carrier lifetime than those in Czochralski silicon and other semiconductor materials, it has potential advantages to fabricate bipolar detectors on the high-purity FZ silicon substrate to achieve a high gain at ultra-low-signal levels. The authors present preliminary experimental results on a bipolar detector fabricated on an unusual high-purity FZ silicon substrate. A backside gettering layer of phosphorus-doped polysilicon was employed to preserve the long carrier lifetime of the high-purity FZ silicon. The device has been investigated in the detection of a continuous flux of X-ray and infrared light. The bipolar detector with a circular emitter of 2 mm diameter has demonstrated high gains up to 3820 for 22 keV X-ray from a 1 mCi Cd radioactive source (the X-ray photon flux, received by the detector is estimated to be ∼7.77×104/s). High gain up to 4400 for 0.17 nW light with a wavelength of 0.83 μm has been observed for the same device. [Copyright &y& Elsevier]

Since float-zone (FZ) silicon has lower contamination and longer minority carrier lifetime than those in Czochralski silicon and other semiconductor materials, it has potential advantages to fabricate a bipolar junction transistor on the FZ substrate to achieve high gain at very low current levels. In this report, the authors present preliminary experimental results on supergain bipolar junction transistors fabricated on unusual FZ refined high-resistivity silicon substrate and by ion implantation technology. A phosphorus-doped polycrystalline silicon backside gettering layer has been employed to preserve the long carrier lifetime of the high-purity FZ silicon. Bipolar junction transistors have demonstrated high current gain, more than 3300 for ultralow base current levels of 10 pA in this study. Possible applications of high-purity FZ silicon on some advanced semiconductor devices and circuits are discussed in this letter. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We tagged 125 sea trout kelts (460–925 mm) in seven Danish rivers with positively buoyant DSTs. Fifty-three (42%) tags were recovered, enabling a comparison of behaviour in kelts that survived the marine period and kelts that did not. Data revealed an estimated mean survival time at sea of 14.3 days (range 1–65 days) for fish that died at sea. Fish that did not survive had lower weight/length ratios when tagged than survivors (P = 0.005) but exhibited a similar diel diving pattern while at sea. Both surviving and non-surviving fish gradually increased diving activity and the daily visited maximum depths after sea entry, but some performed fewer dives and resided in shallower depths than others. This difference was pronounced when comparing surviving fish (most active divers) with fish caught by anglers (least active divers). The results show that the first weeks at sea are critical for kelt survival and that physical status of kelts may affect behaviour and probability of survival. The preference for shallower waters and less diving activity in some individuals indicate that coastally based fisheries and recreational angling may select against specific behavioural phenotypes which should be investigated more intensively. Image 1 • Sea trout (Salmo trutta) kelts were studied with a novel type of data storage tag. • Mortality was high in the first three weeks after sea entry. • Non-surviving fish had lower weight/length ratios when tagged than surviving fish. • Surviving fish performed more frequent foraging dives than non-surviving fish. • Angling from the coast could select against specific phenotypes in sea trout. [ABSTRACT FROM AUTHOR]

In this study the possibility of retrieving composition information in proton therapy with a planar in-beam PET scanner is investigated. The analysis focuses both on spatial activity distributions and time dependence of the recorded signal. The experimental data taking was performed at the Trento Proton Therapy Center (IT) by irradiating three different phantoms. We show that different phantom compositions reflect into different activity profile shapes. We demonstrate that the analysis of the event rate can provide significant information on the phantom elemental composition, suggesting that elemental analysis could be used along with activity profile analysis to achieve a more accurate treatment monitoring. [ABSTRACT FROM AUTHOR]

Background: Micro-CT is an established imaging technique for high-resolution non-destructive assessment of vascular samples, which is gaining growing interest for investigations of atherosclerotic arteries both in humans and in animal models. However, there is still a lack in the definition of micro-CT image metrics suitable for comprehensive evaluation and quantification of features of interest in the field of experimental atherosclerosis (ATS).Objective: A novel approach to micro-CT image processing for profiling of coronary ATS is described, providing comprehensive visualization and quantification of contrast agent-free 3D high-resolution reconstruction of full-length artery walls.Methods: Accelerated coronary ATS has been induced by high fat cholesterol-enriched diet in swine and left coronary artery (LCA) harvested en bloc for micro-CT scanning and histologic processing. A cylindrical coordinate system has been defined on the image space after curved multiplanar reformation of the coronary vessel for the comprehensive visualization of the main vessel features such as wall thickening and calcium content. A novel semi-automatic segmentation procedure based on 2D histograms has been implemented and the quantitative results validated by histology.Results: The potentiality of attenuation-based micro-CT at low kV to reliably separate arterial wall layers from adjacent tissue as well as identify wall and plaque contours and major tissue components has been validated by histology. Morphometric indexes from histological data corresponding to several micro-CT slices have been derived (double observer evaluation at different coronary ATS stages) and highly significant correlations (R2 > 0.90) evidenced. Semi-automatic morphometry has been validated by double observer manual morphometry of micro-CT slices and highly significant correlations were found (R2 > 0.92).Conclusion: The micro-CT methodology described represents a handy and reliable tool for quantitative high resolution and contrast agent free full length coronary wall profiling, able to assist atherosclerotic vessels morphometry in a preclinical experimental model of coronary ATS and providing a link between in vivo imaging and histology. [ABSTRACT FROM AUTHOR]

During particle therapy irradiation, positron emitters with half-lives ranging from 2 to 20 min are generated from nuclear processes. The half-lives are such that it is possible either to detect the positron signal in the treatment room using an in-beam positron emission tomography (PET) system, right after the irradiation, or to quickly transfer the patient to a close PET/CT scanner. Since the activity distribution is spatially correlated with the dose, it is possible to use PET imaging as an indirect method to assure the quality of the dose delivery. In this work, we present a new dedicated PET system able to operate in-beam. The PET apparatus consists in two 10 cm × 10 cm detector heads. Each detector is composed of four scintillating matrices of 23 × 23 LYSO crystals. The crystal size is 1.9 mm × 1.9 mm × 16 mm. Each scintillation matrix is read out independently with a modularized acquisition system. The distance between the two opposing detector heads was set to 20 cm. The system has very low dead time per detector area and a 3 ns coincidence window, which is capable to sustain high single count rates and to keep the random counts relatively low. This allows a new full-beam monitoring modality that includes data acquisition also while the beam is on. The PET system was tested during the irradiation at the CATANA (INFN, Catania, Italy) cyclotron-based proton therapy facility. Four acquisitions with different doses and dose rates were analysed. In all cases the random to total coincidences ratio was equal or less than 25%. For each measurement we estimated the accuracy and precision of the activity range on a set of voxel lines within an irradiated PMMA phantom. Results show that the inclusion of data acquired during the irradiation, referred to as beam-on data, improves both the precision and accuracy of the range measurement with respect to data acquired only after irradiation. Beam-on data alone are enough to give precisions better than 1 mm when at least 5 Gy are delivered. [ABSTRACT FROM AUTHOR]

In fully three-dimensional PET imaging, iterative image reconstruction techniques usually outperform analytical algorithms in terms of image quality provided that an appropriate system model is used. In this study we concentrate on the calculation of an accurate system model for the YAP-(S)PET II small animal scanner, with the aim to obtain fully resolution- and contrast-recovered images at low levels of image roughness. For this purpose we calculate the system model by decomposing it into a product of five matrices: (1) a detector response component obtained via Monte Carlo simulations, (2) a geometric component which describes the scanner geometry and which is calculated via a multi-ray method, (3) a detector normalization component derived from the acquisition of a planar source, (4) a photon attenuation component calculated from x-ray computed tomography data, and finally, (5) a positron range component is formally included. This system model factorization allows the optimization of each component in terms of computation time, storage requirements and accuracy. The main contribution of this work is a new, efficient way to calculate the detector response component for rotating, planar detectors, that consists of a GEANT4 based simulation of a subset of lines of flight (LOFs) for a single detector head whereas the missing LOFs are obtained by using intrinsic detector symmetries. Additionally, we introduce and analyze a probability threshold for matrix elements of the detector component to optimize the trade-off between the matrix size in terms of non-zero elements and the resulting quality of the reconstructed images. In order to evaluate our proposed system model we reconstructed various images of objects, acquired according to the NEMA NU 4-2008 standard, and we compared them to the images reconstructed with two other system models: a model that does not include any detector response component and a model that approximates analytically the depth of interaction as detector response component. The comparisons confirm previous research results, showing that the usage of an accurate system model with a realistic detector response leads to reconstructed images with better resolution and contrast recovery at low levels of image roughness. [ABSTRACT FROM AUTHOR]

Assessing psychosocial factors in occupational environment requires complicated procedures according to most methods. The project of Tuscany region has the aim to realize a free computerized instrument for a gradual risk assessment with two different modes, expert and beginner. A decisional flow chart helps to approach the risk assessment step by step on the basis of company features, management and organization problems and company symptoms of stress. This experience means a proposal of a computerized method for a quantitative assessment of psychosocial risks at workplace, but at the same time offers a detailed analysis of the problems in the organization suggesting different priority to solve them. [ABSTRACT FROM AUTHOR]

Abstract: Commercially constructed crystal matrices are characterised for use with PSPMT detectors for PET system developments and other nuclear medicine applications. The matrices of different scintillation materials were specified with pixel dimensions of 1.5×1.5mm2 in cross-section and a length corresponding to one gamma ray interaction length at 511keV. The materials used in this study were BGO, LSO, LYSO, YSO and CsI(Na). Each matrix was constructed using a white TiO loaded epoxy that forms a 0.2mm septa between each pixel. The white epoxy is not the optimum choice in terms of the reflective properties, but represents a good compromise between cost and the need for optical isolation between pixels. We also tested a YAP matrix that consisted of pixels of the same size specification but was manufactured by a different company, who instead of white epoxy, used a thin aluminium reflective layer for optical isolation that resulted in a septal thickness of just 0.01mm, resulting in a much higher packing fraction. The characteristics of the scintillation materials, such as the light output and energy resolution, were first studied in the form of individual crystal elements by using a single pixel HPD. A comparison of individual pixels with and without the epoxy/dielectric coatings was also performed. Then the matrices themselves were coupled to a PSPMT in order to study the imaging performance. In particular, the system pixel resolution and the peak to valley ratio were measured at 511 and 122keV. [Copyright &y& Elsevier]

The usefulness to generate attenuation maps from computed tomography (CT) system for compensation of photon attenuation in single photon emission computed tomography (SPECT) mammographic evaluation is discussed. The present investigation is part of a general project intended to perform co-registration of functional and morphological information. The experimental apparatus consists of a quasi-monochromatic X-ray computed tomography and a high resolution compact gamma camera. The projection data are reconstructed using filtered backprojection to form the X-ray CT image, which is then properly scaled to produce an estimate of the attenuation map at the energy of the emission nuclide. The scaling is done following a two phases model of the breast tissue which takes into account the realistic average composition of the basic components. It is shown that both for simulations and measurements, the attenuation maps, generated from the CT images, estimate accurately the attenuation of breast in the reconstructed SPECT evaluations. [Copyright &y& Elsevier]

A small animal PET-SPECT scanner (YAPPET) prototype was built at the Physics Department of the Ferrara University and is presently being used at the Nuclear Medicine Department for radiopharmaceutical studies on rats. The first YAPPET prototype shows very good performances, but needs some improvements before it can be fully used for intensive radiopharmaceutical research. The main problem of the actual prototype is its heavy electronics, based on NIM and CAMAC standard modules. For this reason a new, compact read-out electronics was developed and tested. The results of a first series of tests made on the first prototype will be presented in the paper. [Copyright &y& Elsevier]

In an effort to better understand the phenomenon of lipotoxicity in human beta-cells, we evaluated the effects of 48-h preculture with 1.0 or 2.0 mmol/l free fatty acid (FFA) (2:1 oleate to palmitate) on the function and survival of isolated human islets and investigated some of the possible mechanisms. Compared with control islets, triglyceride content was significantly increased and insulin content and glucose-stimulated insulin release were significantly reduced in islets precultured with increased FFA concentrations. These changes were accompanied by a significant reduction of glucose utilization and oxidation. By cell death detection techniques, it was observed that exposure to FFAs induced a significant increase of the amount of dead cells. Electron microscopy showed the involvement of beta-cells, with morphological appearance compatible with the presence of apoptotic phenomena. FFA-induced islet cell death was blocked by inhibition of upstream caspases and partially prevented by inhibiton of ceramide synthesis or serine protease activity, whereas inhibition of nitric oxide synthesis had no effect. RT-PCR studies revealed no major change of iNOS and Bax mRNA expression and a marked decrease of Bcl-2 mRNA expression in the islets cultured with FFA. Thus, prolonged exposure to FFAs has cytostatic and pro-apoptotic effects on human pancreatic beta-cells. The cytostatic action is likely to be due to the FFA-induced reduction of intraislet glucose metabolism, and the proapoptotic effects are mostly caspase mediated, partially dependent on ceramide pathway, and possibly Bcl-2 regulated. [ABSTRACT FROM AUTHOR]

A dedicated small animal PET scanner, YAPPET, was designed and built at Ferrara University. Each detector consists of a 20×20 matrix of 2×2×30 mm3 YAP:Ce finger-like crystals glued together and directly coupled to a Hamamatsu position sensitive photomultiplier. The scanner is made from four detectors positioned on a rotating gantry at a distance of 7.5 cm from the center and the field of view (FOV) is 4 cm both in the transaxial direction and in the axial direction. The system operates in 3D acquisition mode. The performance parameters of YAPPET scanner such as spatial, energy and time resolution, as well as its sensitivity and counting rate have been determined. The average spatial resolution over the whole FOV is 1.8 mm at FWHM and 4.2 mm at FWTM. The sensitivity at the center is 640 cps/μCi. [Copyright &y& Elsevier]

Three different types of Position Sensitive PhotoMultiplier tube have been studied and compared in terms of their imaging performance when coupled to scintillator arrays. Such position sensitive tubes often form the basis for the coincident detection of the 511 keV gamma-rays produced as a result of positron annihilation in PET. The three tubes studied here are the R2486, the R8520 and the H8500 all from Hamamatsu and span a number of years of technological development. The R2486 is a circular tube that has a photocathode of diameter 50 mm and a body diameter of 76 mm. The R8520 is a compact 25.7×25.7 mm2 square detector with a 22×22 mm2 active area. The H8500, also called the flat panel tube, is a large area square detector of 52×52 mm2 with an active area of 49×49 mm2. A 40×40 mm2 YAP:Ce matrix composed of 2×2×25 mm3 pixels is used in order to assess the imaging performance of each tube at 511 keV. This imaging performance is characterised here in terms of the image pixel FWHM and the peak-to-valley ratio. After the presentation of these results a discussion is given of the relative merits of each tube and its suitability for future PET applications. [Copyright &y& Elsevier]