Endoscopic ultrasound (EUS) elastography represents a new imaging procedure that might characterize the differences of hardness and strain between diseased tissue and normal tissue. The aim of this ...study was to assess the efficiency of EUS elastography for the differentiation of focal masses in chronic pancreatitis and pancreatic cancer.
The study group comprised 258 patients with focal pancreatic masses included prospectively at 13 participating centers. Qualitative analysis of the diagnoses made by two expert doctors using all recorded video clips was performed in order to test the interobserver variability. A post-processing software analysis was used to examine the EUS elastography videos by calculating average-hue histograms of individual elastography images. The quantitative information was used to calculate intra-observer variability and the accuracy of the method.
Qualitative analysis of the recorded videos revealed a kappa value of 0.72. Intra-observer variability analysis revealed that the single measure intraclass correlation ranged between 0.86 and 0.94. The average-hue histogram analysis of the data indicated a sensitivity of 93.4 %, a specificity of 66.0 %, a positive predictive value of 92.5 %, a negative predictive value of 68.9 %, and an overall accuracy of 85.4 %, based on a cut-off value of 175. Area under the receiver operating characteristic curve (AUROC) was 0.854 ( P < 0.0001) with a confidence interval of 0.804 - 0.894.
The value of quantitative analysis of EUS elastography recordings was proven by good reproducibility of the videos, as well as good parameters of the AUROC analysis. (Clinical Trials.gov identifier: CT00909103).
Spectroscopic characteristics of Pr3+ ions doped CNGG and CLNGG single crystals were investigated in order to assess their potential as laser materials for visible emission. The Judd-Ofelt intensity ...parameters for the f-f transitions of Pr3+ ions were used to determine spectroscopic and laser emission features. The temperature dependence of the absorption spectra for the 3H4 → 3P0 transition was used to highlight the multicenter structure, different Stark levels, hot bands, and also the connection between the vibronic and electronic lines. The presence of electron-phonon interaction was also observed in the emission spectra corresponding to the 3P0 → 3H4 transition under different excitation wavelengths. Based on low temperature absorption and emission spectra, partial energy level diagrams of Pr3+ ions doped in CNGG and CLNGG single crystals were obtained. The emission cross-sections for different transitions of Pr3+ ions were evaluated by the Fuchtbauer-Ladenburg formula. The fluorescence decay curve of the 1D2 level was measured under selective excitation at different concentrations and temperatures. The concentration quenching process for the 1D2 state was also studied.
•Optical properties ofPr3+ ions in CNGG and CLNGG crystals have been investigated.•Judd-Ofelt parameters and radiative properties of Pr3+ ions have been calculated.•Partial energy level diagrams of Pr3+ions dopedCNGG and CLNGG were determined.•Pr-dopedCNGG and CLNGG are promising laser materials in the visible domain.
Lead isotopic ratios of cassiterite, the dominant ore of tin, evolve after crystallization through decay of uranium (U) and thorium (Th) to lead (Pb), due to the relatively elevated U/Pb ratios of ...this mineral. We show that the Pb isotopic ratios of smelted tin at Rooiberg, South Africa, form an isochron with a model age that matches the known geological age (∼2 Ga) of the host granite for the Rooiberg cassiterite deposits. Since the Pb isotopic ratios of many prehistoric tin and bronze artifacts throughout southern Africa also fall on this isochron, we deduce that they were made with tin from either the Rooiberg deposits or similar age deposits that exist nearby. In addition, we show that bronze artifacts from Romania define an isochron corresponding to a Variscan age (∼0.3 Ga), suggesting a central or western European tin deposit as its source, since no Variscan tin is known from the neighboring Carpathian Mountains. Implications of this approach for provenance studies of tin and bronzes around the world are examined given various major tin deposits and their age distribution.
Systematic and continuous monitoring of athletic performance for the purpose of developing incrementally adaptive optimized training solutions is often presented as the future of more efficient ...training systems. This is a shared view in the specialty literature, with authors such as Lyle J (2005, p. 21) stating that "operational training implies the existence of a continuous monitoring process, not only within a competition but also within the training and preparation". The periodic analysis of key performance parameters with a great effect on performance during a sports contest is a process based on a coherent, self-adaptive and continuously developing system, being the result of a a systemic analysis mechanism that focuses on the analytical evaluation, data collection and analytics, interpreting, and reporting the information obtained as a result of the research. Our approach is to apply and expand on the video analysis method by focusing on certain key questions: how much, how well, how precise but with what costs, with what effort, with what efficiency. Eliminating the "traditional" methods prompt the conclusions that using advanced mechatronic devices render us capable continuous monitoring, recording, and developing comparison solutions that enable concrete interventions on improving the technical execution of various athletic events and more.
The response of a position-sensitive Li-glass scintillator detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using collimated beams of thermal ...neutrons. The detector was moved perpendicularly through the neutron beams in 0.5 to 1.0 mm horizontal and vertical steps. Scintillation was detected in an 8 × 8 pixel multi-anode photomultiplier tube on an event-by-event basis. In general, several pixels registered large signals at each neutron-beam location. The number of pixels registering signal above a set threshold was investigated, with the maximization of the single-hit efficiency over the largest possible area of the detector as the primary goal. At a threshold of ∼50% of the mean of the full-deposition peak, ∼80% of the events were registered in a single pixel, resulting in an effective position resolution of ∼5 mm in X and Y. Lower thresholds generally resulted in events demonstrating higher pixel multiplicities, but these events could also be localized with ∼5 mm position resolution.
Comparative high resolution spectroscopic investigation between 10 and 300 K of the less investigated Pr3+ and Sm3+ ions in the YAG crystals and transparent ceramics evidenced that the satellite ...structures around the main optical lines corresponding to the ions in the dodecahedral c-sites belong either to ions whose crystal field is perturbed by adjacent lattice irregularities or to vibronics. In case of Pr:YAG such irregularities are mainly caused by presence of doping ions in near sites (n.n. and n.n.n. pairs) in both types of materials, while in the melt-grown crystal an additional irregularity is the presence of excess Y3+ ions that occupy part of the octahedral Al3+ sites. The new data on perturbed Pr3+ pair centers remove the ambiguity in identification of several lines that were previously attributed to transitions of the isolated Pr3+ ions forbidden in the D2 symmetry of YAG ceramics and rule out the forced assumption of lowering of symmetry. In case of Sm3+:YAG ceramic the main perturbed center corresponds to n.n. pairs and plays major role in utilization of this material as ASE suppressor for the Nd:YAG laser. The presence of electron-phonon interaction was evidenced by shift or broadening of lines or by resolved weak vibronic structures. For selected optical transitions, such as the 10 K Sm3+4G5/2 → 6H5/2,7/2,9/2 emission in YAG the presence of enhanced electron-phonon effects was evidenced by strong alteration of the shape of electronic lines, such as apparition of asymmetries or even doubling of electronic lines whose Stark gap to other transitions is in quasi-resonance with Raman phonons of YAG. zero phonon lines at energies close to Raman phonons of YAG of T2g symmetry. The shape of the lines is analyzed in terms of the theory of the quasi-resonant electron-phonon coupling between a pure electronic state and vibronics.
•New high resolution spectral data for Pr:YAG and Sm:YAG in crystals or transparent ceramics.•First unambiguous assignment of the satellite structure of Pr:YAG.•Vibronics in Pr3+3P0 → 3H4, 1D2 → 3H4 emission spectra of YAG ceramics.•Near-resonant electron-phonon interaction in 4G5/2 → 4HJ emission lines of Sm:YAG ceramic.
Yttrium aluminum garnet (Yb3+:Y3Al5O12) laser ceramics doped by 5, 10 and 15 at% of ytterbium ions were obtained by reactive sintering. Optimal sintering temperature range for the formation of ...highly-dense transparent Yb3+:Y3Al5O12 ceramics under normal recrystallization conditions was found to be T=1750–1800°C. The influence of Yb3+ ions on structural-phase state, phase composition, microstructure, optical and luminescent properties of sintered samples was experimentally investigated. It was shown that lattice parameter a of Yb3+:Y3Al5O12 ceramics decreases linearly with increasing of Yb3+ concentration in a good agreement with L. Vegard’s rule, that indicates to the formation of (Y1−xYbx)3Al5O12 (х=0.05–0.15) substitutional solid solutions. No concentration quenching of Yb3+ luminescence was observed in Yb3+:Y3Al5O12 within the 5–15 at% doping range. Quasi-CW lasing of Yb3+:Y3Al5O12 ceramics was studied under diode-pumping at 970nm. A highest slope efficiency of about 50% was obtained for 15 at%-doped Yb3+:Y3Al5O12 ceramics sintered at T=1800°C for 10h.
Abstract Abstract The stress of Antenatal Maternal Hypoxia (AMH) can lead to a number of physiological and pathological changes in both mother and fetus, changes which can be linked to alterations in ...placental morphology and gene regulation. Recently, in the Brown Norway rat “model” of placental insufficiency, we reported alterations in placental renin-angiotensin system (RAS) genes. Moreover, AMH can lead to reduced oxygen availability to the fetus, similar to a state of placental insufficiency. Thus, in pregnant mice dams we tested the hypothesis that antenatal maternal hypoxic stress leads to alterations in the placental RAS. These alterations may, in part, account for the phenotypic changes in both pregnant mice dams as well as fetus and adult offspring. Methods Pregnant FVB/NJ mice dams were either maintained as controls, or exposed to 10.5% O2 for 48 h from 15.5 to 17.5 day post coitum. We then measured placental mRNA and protein expression of several RAS genes ( n = 4 to 5; P < 0.05 was considered significant). Result In murine placenta: (1) angiotensinogen (AGT) mRNA was undetectable; however, AGT protein was detectable and increased significantly with AMH. (2) In AMH, although renin mRNA was reduced protein expression increased, in association with decreased microRNA (miRNA) 199b, which can lead to increased renin translation. (3) Also in AMH placenta, angiotensin converting enzyme (ACE) -1 mRNA was unaltered; however, protein expression increased significantly, in association with decreased miRNA 27a, which can result in increased ACE-1 translation. (4) In AMH placenta, ACE-2 mRNA was reduced significantly, whereas protein expression was significantly greater, in association with reduced miRNA 429. (5) In AMH placenta, angiotensin II type (AT) -1a receptor mRNA expression was unaltered while AT-1b receptor mRNA was undetectable in both groups. Moreover, AT-1 receptor protein expression was unchanged in response to AMH. (6) AT-2 receptor mRNA and proteins were undetectable in both groups. Conclusion The normal murine placenta possesses several components of RAS, and in response to AMH several of these elements undergo important changes. In addition, differential expression of RAS mRNA, miRNA and protein, indicate post-transcriptional regulatory mechanisms involved with hypoxic stress, and necessitate further investigation.
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