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Core-collapse Supernovae (SNe) are one of the most energetic events in the Universe, during which almost all the star's binding energy is released in the form of neutrinos. These particles are direct probes of the processes occurring in the stellar core and provide unique insights into the gravitational collapse. RES-NOVA will revolutionize how we detect neutrinos from astrophysical sources, by deploying the first ton-scale array of cryogenic detectors made from archaeological lead. Pb offers the highest neutrino interaction cross-section via coherent elastic neutrino-nucleus scattering (CEνNS). Such process will enable RES-NOVA to be equally sensitive to all neutrino flavours. For the first time, we propose the use archaeological Pb as sensitive target material in order to achieve an ultra-low background level in the region of interest (O(1 keV)). All these features make possible the deployment of the first cm-scale neutrino telescope for the investigation of astrophysical sources. In this contribution, we will characterize the radiopurity level and the performance of a small-scale proof-of-principle detector of RES-NOVA, consisting in a PbWO4 crystal made from archaeological-Pb operated as cryogenic detector.
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CRESST is a leading direct detection sub-GeVc-2 dark matter experiment. During its second phase, cryogenic bolometers were used to detect nuclear recoils off the CaWO4 target crystal nuclei. The previously established electromagnetic background model relies on Secular Equilibrium (SE) assumptions. In this work, a validation of SE is attempted by comparing two likelihood-based normalisation results using a recently developed spectral template normalisation method based on Bayesian likelihood. Albeit we find deviations from SE in some cases we conclude that these deviations are artefacts of the fit and that the assumptions of SE is physically meaningful.
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Analyzing COVID-19-related stress in children with affective dysregulation (AD) seems especially interesting, as these children typically show heightened reactivity to potential stressors and an increased use of maladaptive emotion regulation strategies. Children in out-of-home care often show similar characteristics to those with AD. Since COVID-19 has led to interruptions in psychotherapy for children with mental health problems and to potentially reduced resources to implement treatment strategies in daily life in families or in out-of-home care, these children might show a particularly strong increase in stress levels. In this study, 512 families of children without AD and 269 families of children with AD reported on COVID-19-related stress. The sample comprised screened community, clinical, and out-of-home care samples. Sociodemographic factors, characteristics of child and caregiver before the pandemic, and perceived change in external conditions due to the pandemic were examined as potential risk or protective factors. Interestingly, only small differences emerged between families of children with and without AD or between subsamples: families of children with AD and families in out-of-home care were affected slightly more, but in few domains. Improvements and deteriorations in treatment-related effects balanced each other out. Overall, the most stable and strongest risk factor for COVID-19-related stress was perceived negative change in external conditions-particularly family conditions and leisure options. Additionally, caregiver characteristics emerged as risk factors across most models. Actions to support families during the pandemic should, therefore, facilitate external conditions and focus on caregiver characteristic to reduce familial COVID-19-related stress. Trial registration: German Clinical Trials Register (DRKS), ADOPT Online: DRKS00014963 registered 27 June 2018, ADOPT Treatment: DRKS00013317 registered 27 September 2018, ADOPT Institution: DRKS00014581 registered 04 July 2018.
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COVID-19 , Regulação Emocional , Criança , Humanos , Pandemias , Fatores de Proteção , PsicoterapiaRESUMO
The preparation of novel technetium oxides, their characterization and the general investigation of technetium chemistry are of significant importance, since fundamental research has so far mainly focused on the group homologues. Whereas the structure chemistry of technetium in strongly oxidizing media is dominated by the Tc O 4 - ${{\left[{\rm { Tc}}{{\rm { O}}}_{{\rm { 4}}}\right]}^{-}}$ anion, our recent investigation yielded the new Tc O 3 N 2 - ${{\left[{\rm { Tc}}{{\rm { O}}}_{{\rm { 3}}}{\rm { N}}\right]}^{{\rm { 2}}-}}$ anion. Brown single crystals of Ba[TcO3 N] were obtained under hydrothermal conditions starting from Ba(OH)2 â 8H2 O and NH4 [TcO4 ] at 200 °C. Ba [ Tc O 3 N ] ${{\rm { Ba[Tc}}{{\rm { O}}}_{{\rm { 3}}}{\rm { N]}}}$ crystallizes in the monoclinic crystal system with the space group P21 /n (a=7.2159(4)â Å, b=7.8536(5)â Å, c=7.4931(4)â Å and ß=104.279(2)°). The crystal structure of Ba [ Tc O 3 N ] ${{\rm { Ba[Tc}}{{\rm { O}}}_{{\rm { 3}}}{\rm { N]}}}$ consists of isolated Tc O 3 N 2 - ${{\left[{\rm { Tc}}{{\rm { O}}}_{{\rm { 3}}}{\rm { N}}\right]}^{{\rm { 2}}-}}$ tetrahedra, which are surrounded by Ba2+ cations. XANES measurements complement the oxidation state +VII for technetium and Raman spectroscopic experiments on Ba[TcO3 N] single crystals exhibit characteristic Tc-O and Tc-N vibrational modes.
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The short-range structures of LiF-ThF4, NaF-AnF4, KF-AnF4, and Cs-AnF4 (An = Th, U), were probed using in situ high temperature Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. Signally, the EXAFS spectra of pure molten ThF4 and UF4 were measured for the first time. The data were interpreted with the aid of Molecular Dynamics (MD) and standard fitting of the EXAFS equation. As in related studies, a speciation distribution dominated by [AnFx]4-x (x = 7, 8, 9) coordination complexes was observed. The average coordination number was found to decrease with the increasing size of the alkali cation, and increase with AnF4 content. An average coordination number close to 6, which had not been detected before in melts of alkali actinide fluorides, was seen when CsF was used as solvent.
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The speciation, thermodynamics and structure of the Np(v) (as the NpO2+ cation) complexes with oxalate (Ox2-) are studied by different spectroscopic techniques. Near infrared absorption spectroscopy (Vis/NIR) is used to investigate complexation reactions as a function of the total ligand concentration ([Ox2-]total), ionic strength (Im = 0.5-4.0 mol kg-1 Na+(Cl-/ClO4-)) and temperature (T = 20-85 °C) for determination of the complex stoichiometry and thermodynamic functions (log ß0n(T), ΔrH0n, ΔrS0n). Besides the solvated NpO2+ ion, two NpO2+ oxalate species (NpO2(Ox)n1-2n; n = 1, 2) are identified. With increasing temperature a decrease of the molar fractions of the 1 : 1 - and 1 : 2 - complexes is observed. Application of the law of mass action yields the temperature dependent conditional stability constants log ß'n(T) at a given ionic strength which are extrapolated to IUPAC reference state conditions (Im = 0) according to the specific ion interaction theory (SIT). The log ß0n(T) values of both complex species (log ß01(25 °C) = 4.53 ± 0.12; log ß02(25 °C) = 6.22 ± 0.24) decrease with increasing temperature confirming an exothermic complexation reaction. The temperature dependence of the thermodynamic stability constants is described by the integrated van't Hoff equation yielding the standard reaction enthalpies (ΔrH01 = -1.3 ± 0.7 kJ mol-1; ΔrH02 = -8.7 ± 1.4 kJ mol-1) and entropies (ΔrS01 = 82 ± 2 J mol-1 K-1; ΔrS02 = 90 ± 5 J mol-1 K-1) for the complexation reactions. In addition, the sum of the specific binary ion-ion interaction coefficients Δε0n(T) for the complexation reactions are obtained from SIT modelling as a function of the temperature. The structure of the complexes and the coordination mode of oxalate are investigated using EXAFS spectroscopy and quantum chemical calculations. The results show, that in case of both species NpO2(Ox)- and NpO2(Ox)23-, chelate complexes with 5-membered rings are formed.
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The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) dark matter search experiment aims for the detection of dark matter particles via elastic scattering off nuclei in CaWO 4 crystals. To understand the CRESST electromagnetic background due to the bulk contamination in the employed materials, a model based on Monte Carlo simulations was developed using the Geant4 simulation toolkit. The results of the simulation are applied to the TUM40 detector module of CRESST-II phase 2. We are able to explain up to ( 68 ± 16 ) % of the electromagnetic background in the energy range between 1 and 40 keV .
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In this study a novel technique, micro-focus time-resolved laser-induced luminescence spectroscopy (µTRLFS) is presented to investigate heterogeneous systems like granite (mainly consisting of quartz, feldspar, and mica), regarding their sorption behavior. µTRLFS is a spatially-resolved upgrade of conventional TRLFS, which allows point-by-point analysis of single minerals by reducing the beam size of the analytic laser beam to below the size of mineral grains. This provides visualization of sorption capacity as well as speciation of a luminescent probe, here Eu3+. A thin-section of granitic rock from Eibenstock, Saxony, Germany was analyzed regarding its mineralogy with microprobe X-ray fluorescence (µXRF) and electron probe microanalysis (EPMA). Afterwards, it was reacted with 5.0 × 10-5 mol/L Eu3+ at pH 8.0 and uptake was quantified by autoradiography. Finally, the µTRLFS studies were conducted. The results clearly show that the materials interact differently with Eu3+, and often even on one mineral grain different speciations can be found. Alkali-feldspar shows very high uptake, with an inhomogeneous distribution, and intermediate sorption strength. On quartz uptake is almost 10-fold lower, while the complexation strength is higher than on feldspar. This may be indicative of adsorption only at surface defect sites, in accordance with low hydration of the observed species.
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The solubility of 99Tc(iv) was investigated in dilute to concentrated carbonate solutions (0.01 M ≤ Ctot≤ 1.0 M, with Ctot = [HCO3-] + [CO32-]) under systematic variation of ionic strength (I = 0.3-5.0 M NaHCO3-Na2CO3-NaCl-NaOH) and pHm (-log[H+] = 8.5-14.5). Strongly reducing conditions (pe + pHm≈ 2) were set with Sn(ii). Carbonate enhances the solubility of Tc(iv) in alkaline conditions by up to 3.5 log10-units compared to carbonate-free systems. Solvent extraction and XANES confirmed that Tc was kept as +IV during the timeframe of the experiments (≤ 650 days). Solid phase characterization performed by XAFS, XRD, SEM-EDS, chemical analysis and TG-DTA confirmed that TcO2·0.6H2O(am) controls the solubility of Tc(iv) under the conditions investigated. Slope analysis of the solubility data in combination with solid/aqueous phase characterization and DFT calculations indicate the predominance of the species Tc(OH)3CO3- at pHm≤ 11 and Ctot≥ 0.01 M, for which thermodynamic and activity models are derived. Solubility data obtained above pHm≈ 11 indicates the formation of previously unreported Tc(iv)-carbonate species, possibly Tc(OH)4CO32-, although the likely formation of additional complexes prevents deriving a thermodynamic model valid for this pHm-region. This work provides the most comprehensive thermodynamic dataset available for the system Tc4+-Na+-Cl--OH--HCO3--CO32--H2O(l) valid under a range of conditions relevant for nuclear waste disposal.
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CAT-ACT-the hard X-ray beamline for CATalysis and ACTinide/radionuclide research at the KIT synchrotron radiation facility ANKA-is dedicated to X-ray spectroscopy, including "flux hungry" photon-in/photon-out and correlative techniques and combines state-of-the-art optics with a unique infrastructure for radionuclide and catalysis research. Measurements can be performed at photon energies varying between 3.4 keV and 55 keV, thus encompassing the actinide M- and L-edge or potassium K-edge up to the K-edges of the lanthanide series such as cerium. Well-established X-ray absorption fine structure spectroscopy in transmission and fluorescence detection modes is available in combination with high energy-resolution X-ray emission spectroscopy or X-ray diffraction techniques. The modular beamline design with two alternately operated in-line experimental stations enables sufficient flexibility to adapt sample environments and detection systems to many scientific challenges. The ACT experimental station focuses on various aspects of nuclear waste disposal within the mission of the Helmholtz association to contribute to the solution of one of the greatest scientific and social challenges of our time-the safe disposal of heat producing, highly radioactive waste forms from nuclear energy production. It augments present capabilities at the INE-Beamline by increasing the flux and extending the energy range into the hard X-ray regime. The CAT experimental station focuses on catalytic materials, e.g., for energy-related and exhaust gas catalysis. Characterization of catalytically active materials under realistic reaction conditions and the development of in situ and operando cells for sample environments close to industrial reactors are essential aspects at CAT.
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One of the long standing debates in actinide chemistry is the level of localization and participation of the actinide 5f valence orbitals in covalent bonds across the actinide series. Here we illuminate the role of the 5f valence orbitals of uranium, neptunium and plutonium in chemical bonding using advanced spectroscopies: actinide M4,5 HR-XANES and 3d4f RIXS. Results reveal that the 5f orbitals are active in the chemical bonding for uranium and neptunium, shown by significant variations in the level of their localization evidenced in the spectra. In contrast, the 5f orbitals of plutonium appear localized and surprisingly insensitive to different bonding environments. We envisage that this report of using relative energy differences between the 5fδ/φ and 5fπ*/5fσ* orbitals as a qualitative measure of overlap-driven actinyl bond covalency will spark activity, and extend to numerous applications of RIXS and HR-XANES to gain new insights into the electronic structures of the actinide elements.
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A particularly challenging aspect of forensic casework is the accurate interpretation of samples that contain DNA from more than one contributor, since DNA analysis of specific identification markers often results in ambiguous mixed profiles. Physically separating the various haploid components of a diploid or polyploid DNA sample or of a specimen containing DNA from multiple individuals can resolve this problem. We adapted and combined previously developed methods of haplotype-specific extraction (HSE) to separate and analyze mitochondrial DNA (mtDNA) in samples containing DNA from two individuals. After optimizing conditions and probes, we performed HSE to separate mitochondrial DNA mixtures, which manifest as mixed nucleotide calls at single base positions. We were able to subsequently identify the DNA of the two individuals by sequencing. Based on our findings from this proof-of-concept experiment, this novel assay will be useful for distinguishing among the mtDNA of individuals in mixed DNA samples.
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DNA Mitocondrial/genética , Haplótipos , Polimorfismo Genético , Análise de Sequência de DNA/métodos , Impressões Digitais de DNA/métodos , Humanos , Reação em Cadeia da PolimeraseRESUMO
AIM: Pancreatic neuroendocrine tumors (PNETs) pose a diagnostic challenge with respect to the physiologic somatostatin receptor expression in the uncinate process representing a potential pitfall for receptor imaging with PET/CT. METHODS: We identified 49 PNETs from a total of 316 consecutive [68Ga]DOTATOC PET/CT examinations for whom the detections rates of PET and multiphase contrast enhanced (CE-) CT could be retrospectively compared and 38 PNETs for which SUVmax and SUVmax target-to-liver ratios could be calculated for the tumors and the uncinate process. RESULTS: The detection rate of PET (83.7%) was higher than of the different CT phases (arterial: 59.2%, P=0.017; portal-venous: 38.8%, P<0.001; venous: 46.9%, P=0.001; multiphase: 71.4%, P=0.286). Compared to the other method PET revealed 28.6% additional lesions and multiphase CE-CT 16.3%. The portal-venous phase revealed only lesions that were also detected in the arterial or venous phase. The detection rate for PNETs in the uncinate process (N.=9) was 66.7% for PET versus 55.6% for multiphase CE-CT. SUVmax and SUVmax target-to-liver ratios differed significantly (P<0.001) for PNETs (mean, range: SUVmax, 14.6, 1.4-69.3; SUVmax target-to-liver ratio, 3.2, 0.69-23.1) and uncinate process (4.32, 0.8-13.5; 0.94, 0.51-1.56), however with a wide overlap. CONCLUSION: Patients with PNETs should undergo [68Ga]DOTATOC PET/CT with at least an arterial and venous phase CT scan. SUVmax and SUVmax target-to-liver ratios provide additional information but do no reliably separate PNETs from normal tracer uptake in the uncinate process.
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Interpretação de Imagem Assistida por Computador/métodos , Imagem Multimodal/métodos , Tumores Neuroendócrinos/diagnóstico , Octreotida/análogos & derivados , Compostos Organometálicos , Neoplasias Pancreáticas/diagnóstico , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e EspecificidadeRESUMO
Aim: Pancreatic neuroendocrine tumors (PNETs) pose a diagnostic challenge with respect to the physiologic somatostatin receptor expression in the uncinate process representing a potential pitfall for receptor imaging with PET/CT. Methods: We identified 49 PNETs from a total of 316 consecutive [68Ga]DOTATOC PET/CT examinations for whom the detections rates of PET and multiphase contrast enhanced (CE-) CT could be retrospectively compared and 38 PNETs for which SUV max and SUV max target-to-liver ratios could be calculated for the tumors and the uncinate process. Results: The detection rate of PET (83.7%) was higher than of the different CT phases (arterial: 59.2%, P=0.017; portal-venous: 38.8%, P<0.001; venous: 46.9%, P=0.001; multiphase: 71.4%, P=0.286). Compared to the other method PET revealed 28.6% additional lesions and multiphase CE-CT 16.3%. The portal-venous phase revealed only lesions that were also detected in the arterial or venous phase. The detection rate for PNETs in the uncinate process (N.=9) was 66.7% for PET versus 55.6% for multiphase CE-CT. SUV max and SUV max target-to-liver ratios differed significantly (P<0.001) for PNETs (mean, range: SUV max,14.6, 1.4-69.3; SUV max target-to-liver ratio, 3.2, 0.69-23.1) and uncinate process (4.32, 0.8-13.5; 0.94, 0.51-1.56), however with a wide overlap. Conclusion: Patients with PNETs should undergo [68Ga]DOTATOC PET/CT with at least an arterial and venous phase CT scan. SUV max and SUV max target-to-liver ratios provide additional information but do no reliably separate PNETs from normal tracer uptake in the uncinate process.
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A wet chemical method to determine uranium (U) oxidation states in geological material has been developed and tested. The problem faced in oxidation state determinations with wet chemical methods is that U redox state may change when extracted from the sample material, thereby leading to erroneous results. In order to quantify and monitor U redox behavior during the acidic extraction in the procedure, an analysis of added isotopic redox tracers, (236)U(VI) and (232)U(IV), and of variations in natural uranium isotope ratio ((234)U/(238)U) of indigenous U(IV) and U(VI) fractions was performed. Two sample materials with varying redox activity, U bearing rock and U-rich clayey lignite sediment, were used for the tests. The Fe(II)/Fe(III) redox-pair of the mineral phases was postulated as a potentially disturbing redox agent. The impact of Fe(III) on U was studied by reducing Fe(III) with ascorbic acid, which was added to the extraction solution. We observed that ascorbic acid protected most of the U from oxidation. The measured (234)U/(238)U ratio in U(IV) and U(VI) fractions in the sediment samples provided a unique tool to quantify U oxidation caused by Fe(III). Annealing (sample heating) to temperatures above 500 °C was supposed to heal ionizing radiation induced defects in the material that can disturb U redox state during extraction. Good agreement between two independent methods was obtained for DL-1a material: an average 38% of U(IV) determined by redox tracer corrected wet chemistry and 45% for XANES.
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Sedimentos Geológicos/química , Urânio/química , Temperatura Alta , Ferro/química , Minerais/química , Oxirredução , Radiação Ionizante , Espectroscopia por Absorção de Raios XRESUMO
PURPOSE: Pain coping is important in health outcomes. In the current literature, pain coping usually means those goal-directed strategies to manage pain. The study goal was to explore what personal meaning "coping" has for work-disabled individuals in pain. METHOD: Qualitative, in depth interviews with follow-up verification interviews were conducted with 13 volunteers who were off work and in rehabilitation for chronic pain from a musculoskeletal injury. The two main questions were: (1) How did participants understand the term "coping with pain"; and (2) how did they come to this understanding of coping. The theoretical approach was social phenomenology and data were analyzed using thematic analysis. RESULTS: The dominant theme was that pain coping is an intrinsic and life-defining attitude and belief. This understanding primarily arose through early modeling by parents and significant others. Secondary theme was that coping is practical strategies to manage or eliminate pain. This arose through more current interactions with health care providers and others in the social network. CONCLUSIONS: Researchers' and clinicians' view of coping may not always match the views held by individuals with chronic pain. This might impact on the effectiveness of interventions designed to modify coping behaviors, and alternative ways of intervening may be needed.
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Adaptação Psicológica , Dor Crônica/psicologia , Pessoas com Deficiência/psicologia , Dor Musculoesquelética/psicologia , Traumatismos Ocupacionais/psicologia , Adulto , Idoso , Dor Crônica/reabilitação , Pessoas com Deficiência/reabilitação , Feminino , Seguimentos , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Dor Musculoesquelética/reabilitação , Traumatismos Ocupacionais/reabilitação , Medição da Dor , Pesquisa Qualitativa , Estresse Psicológico , Inquéritos e QuestionáriosRESUMO
Tomato plants have their leaves, petioles and stems covered with glandular trichomes that protect the plant against two-spotted spider mites and many other herbivorous arthropods, but also hinder searching by phytoseiid mites and other natural enemies of these herbivores. This trichome cover creates competitor-free and enemy-free space for the tomato russet mite (TRM) Aculops lycopersici (Acari: Eriophyidae), being so minute that it can seek refuge and feed inbetween the glandular trichomes on tomato cultivars currently used in practice. Indeed, several species of predatory mites tested for biological control of TRM have been reported to feed and reproduce when offered TRM as prey in laboratory experiments, yet in practice these predator species appeared to be unable to prevent TRM outbreaks. Using the phytoseiid mite, Amblydromalus limonicus, we found exactly the same, but also obtained evidence for successful establishment of a population of this predatory mite on whole plants that had been previously infested with TRM. This successful establishment may be explained by our observation that the defensive barrier of glandular plant trichomes is literally dropped some time after TRM infestation of the tomato plants: the glandular trichome heads first rapidly develop a brownish discoloration after which they dry out and fall over onto the plant surface. Wherever TRM triggered this response, predatory mites were able to successfully establish a population. Nevertheless, biological control was still unsuccessful because trichome deterioration in TRM-infested areas takes a couple of days to take effect and because it is not a systemic response in the plant, thereby enabling TRM to seek temporary refuge from predation in pest-free trichome-dense areas which continue to be formed while the plant grows. We formulate a hypothesis unifying these observations into one framework with an explicit set of assumptions and predictions to be tested in future experiments.
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Ácaros/fisiologia , Folhas de Planta/anatomia & histologia , Folhas de Planta/parasitologia , Solanum lycopersicum/parasitologia , Tricomas/parasitologia , Animais , Feminino , Herbivoria , Oviposição , Comportamento PredatórioRESUMO
PURPOSE: To evaluate morphologic characteristics and establish a standardized diagnostic algorithm to differentiate benign cystic pancreatic tumors (CPTs) in non-pancreatitis patients using multidetector computed tomography (CT) and magnetic resonance imaging (MRI). MATERIALS AND METHODS: Patients with histopathologically proven CPTs who had undergone MRI and/or CT and subsequent tumor resection in our institution were retrospectively identified. Images were analyzed for morphology and enhancement patterns by three independent blinded observers. Preoperative image findings were correlated with histopathological results. Based on the evaluated morphologic parameters, a standardized diagnostic algorithm was designed to help characterize the lesions. RESULTS: A total of 62 consecutive patients with 64 CPTs were identified from the surgical database (21 intraductal papillary mucinous neoplasms; 10 mucinous cystic neoplasms; 12 serous microcystic adenomas; 3 serous oligocystic adenomas; 6 solid pseudopapillary tumors; 12 neuroendocrine neoplasms). The overall averaged accuracy for the 3 observers was 89.9 % for CT and 93.1 % for MRI with increasing overall accuracy in relation to the experience of the observer (88.2 %, 91.5 %, and 93.8 %, respectively). Overall, the generalized kappa value was 0.69 (CT, 0.64; MRI, 0.76); p < 0.001). The accuracy of the standardized diagnostic algorithm was 91.1 %. CONCLUSION: It is possible to characterize benign CPTs with MRI and CT, while MRI appears to be superior to CT. Diagnostic accuracy depends on the observer's experience. The standardized algorithm can aid in the differential diagnosis but still needs to be tested in other patient populations.
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Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada Multidetectores/métodos , Cisto Pancreático/patologia , Neoplasias Pancreáticas/patologia , Adulto , Idoso , Algoritmos , Meios de Contraste/administração & dosagem , Diagnóstico Diferencial , Feminino , Humanos , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/normas , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores/normas , Pâncreas/patologia , Sensibilidade e EspecificidadeRESUMO
Since its inauguration in 2005, the INE-Beamline for actinide research at the synchrotron source ANKA (KIT North Campus) provides dedicated instrumentation for x-ray spectroscopic characterization of actinide samples and other radioactive materials. R&D work at the beamline focuses on various aspects of nuclear waste disposal within INE's mission to provide the scientific basis for assessing long-term safety of a final nuclear waste repository. The INE-Beamline is accessible for the actinide and radiochemistry community through the ANKA proposal system and the European Union Integrated Infrastructure Initiative ACTINET-I3. Experiments with activities up to 1 × 10(+6) times the European exemption limit are feasible within a safe but flexible containment concept. Measurements with monochromatic radiation are performed at photon energies varying between ~2.1 keV (P K-edge) and ~25 keV (Pd K-edge), including the lanthanide L-edges and the actinide M- and L3-edges up to Cf. The close proximity of the INE-Beamline to INE controlled area labs offers infrastructure unique in Europe for the spectroscopic and microscopic characterization of actinide samples. The modular beamline design enables sufficient flexibility to adapt sample environments and detection systems to many scientific questions. The well-established bulk techniques x-ray absorption fine structure (XAFS) spectroscopy in transmission and fluorescence mode have been augmented by advanced methods using a microfocused beam, including (confocal) XAFS/x-ray fluorescence detection and a combination of (micro-)XAFS and (micro-)x-ray diffraction. Additional instrumentation for high energy-resolution x-ray emission spectroscopy has been successfully developed and tested.
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OBJECTIVE: To assess the possible extent of dose reduction for low-dose computed tomography (CT) in the detection of body-packing (ingested drug packets) as an alternative to plain radiographs in an animal model. MATERIALS AND METHODS: Twelve packets containing cocaine (purity >80%) were introduced into the intestine of an experimental animal (crossbred pig), which was then repeatedly examined by abdominal CT with stepwise dose reduction (tube voltage, 80 kV; tube current, 10-350 mA). Three blinded readers independently evaluated the CT datasets starting with the lowest tube current and noted the numbers of packets detected at the different tube currents used. In addition, 1 experienced reader determined the number of packets detectable on plain abdominal radiographs and ultrasound. RESULTS: The threshold for correct identification of all 12 drug packets was 100 mA for reader 1 and 125 mA for readers 2 and 3. Above these thresholds all 3 readers consistently identified all 12 packets. The effective dose of a low-dose CT scan with 125 mA (including scout view) was 1.0 mSv, which was below that of 2 conventional abdominal radiographs (1.2 mSv). The reader interpreting the conventional radiographs identified a total of 9 drug packets and detected 8 packets by abdominal ultrasound. CONCLUSIONS: Extensive dose reduction makes low-dose CT a valuable alternative imaging modality for the examination of suspected body-packers and might replace conventional abdominal radiographs as the first-line imaging modality.