Fermi-surface pockets in YBa2Cu3O6.5YBa_2Cu_3O_{6.5} : A comparison of ab initio techniques

We study the Fermi surface of metallic, non-magnetic \textit{ortho}-II YBa$_2$Cu$_3$O$_{6.5}$ using three different density-functional-based band-structure techniques (GGA, GGA+U, PSIC). The calculated Fermi surface exhibits no pockets in GGA+U and PSIC, a minor one in GGA. Upon shifting the Fermi level in the vicinity of the calculated value, we instead observe several pocket structures. We calculate their cross-sectional areas and cyclotron masses. Overall, our calculations show no solid evidence of the existence of electron-like --nor, in fact, of any-- Fermi surface pockets in this phase. This suggests that the origin of the pockets should be sought for in other, different phases.Comment: 7 pages, 5 figures, in print on PRB 79 (2009

The relationships between the immunoexpression of KAI1, MMP-2, MMP-9 and steroid receptors expression in endometrial cancer

The role of the parallel expression of the KAI1 protein and metalloproteinases (MMP-2 and MMP-9) in respect to the status of steroid receptors in endometrial cancer is still incompletely understood. The aim of this study was to evaluate the expression of and correlation between KAI1 on one hand and MMP-2 and MMP-9 on the other hand in terms of the status of the estrogen (ER) and progesterone receptors (PR) in 100 patients with endometrial cancer. The expressions of KAI1, MMP-2, MMP-9, ER and PR were assessed immunohistochemically on paraffin-embedded tissues. No correlations were found between these biomarkers and the clinical and pathological parameters of the endometrial cancer. However, in KAI1-positive cases, the expression was limited to a small area of tumor tissue in FIGO stages III–IV. A tendency towards the high expression of MMP-9 and MMP-2 was observed in the advanced stages of endometrial cancer (FIGO IIIA–IV). Positive correlations between the presence of KAI1 and PR and between the presence of MMP-9 and PR were found in endometrial cancer. A positive correlation was also observed between KAI1 and MMP-2 expression, and a borderline one between KAI1 and MMP-9 expression in endometrial cancer. KAI1+/PR+ and KAI1+/ER– immunophenotypes were observed more frequently in FIGO low stages and with well-differentiated tumor grade. However, the KAI1–/ER+ and KAI1–/PR+ immunophenotypes were mainly observed in advanced stages of endometrial cancer. KAI1+/MMP-2+ and KAI1+/MMP-9+ immunophenotypes were observed in FIGO Istage and with well-differentiated tumors. KAI1–/MMP-2+ and KAI1–/MMP-9+ phenotypes were more often observed in FIGO stage II. Our study showed that KAI1 protein, as well as steroid receptors, might modulate MMP-2 and MMP-9 expression in endometrial cancer. Our study revealed that the overlapping expression of the biomarkers investigated here suggests that cooperation between these molecules exists, even at the early stages of endometrial cancer growth, and may determine the speed of tumor cell dissemination and might characterize the biological behavior of endometrial cancer

The role of nesfatin and selected molecular factors in various types of endometrial cancer

Objectives: Endometrial cancers (ECs) are the most common gynaecological cancers in well developed countries. Diabetes and metabolic syndrome are among the biggest risk factors. Nesfatin-1, the adipokine derivative of NUCB2 (nucleobindin derivative 2) is linked to the clinical course of EC. Molecular factors, including mutations in MLH1 and MHS2 genes, c-MET and ARID1A are also related to prognosis in endometrial cancer. Material and methods: Using sections of paraffin-embedded preparations and immunohistochemistry, the expression of NESF1, MLH1, MSH2,c-MET and ARID1A were examined. Results: In this study on protein expression, EC tissues manifested (although insignificantly) an elevated expression of NESF-1 in type II EC. In type I EC, NESF-1 expression was significantly higher in G1 in comparison to G2 and G3 together. A significantly lower expression of MLH1 was demonstrated in type I EC. Conclusions: The most pronounced expression involved c-MET in all EC I and EC II tissues (in over 80% of cases). A tendency was detected for a high expression of NESF-1 in patients with type II EC, who also exhibited a high expression of MSH2

Measurements of Matching and High Count Rate Performance of Multichannel ASIC for Digital X-Ray Imaging Systems

We present the measurements of matching and high count rate performance of a 64 channel readout ASIC called DEDIX for high count rate position-sensitive measurements using semiconductor detectors. The ASIC is designed in 0.35 mum CMOS process and its total area is 3900 times 5000 mum2. The DEDIX has a binary readout architecture. Each channel is built of a charge sensitive amplifier (CSA) with a pole-zero cancellation circuit, a shaper, two independent discriminators and two independent 20-bit counters. The size of the input device in CSA has been optimized for a detector capacitance in the range of 1-3 pF per strip. An equivalent noise charge of 110 el rms has been achieved for a total detector capacitance of 1 pF at the shaper peaking time of 160 ns. Internal correction DAC implemented in each channel independently ensures a low spread of discriminator effective threshold, namely 0.4 mV at one sigma level. The mean gain in the multichannel ASIC is 54 muV/el, with a good uniformity from channel-to-channel (sd/mean ap 0.8%). Low noise performance and high rate capability have been demonstrated by the measurement up to and above 1 MHz average rate of input signals

Characterization of Seamless CdTe Photon Counting X-Ray Detector

Spectrally selective X-ray imaging provides improved material and tissue discrimination in comparison with the state-of-the-art dual energy technologies that are commonly used in medical, industrial, and security applications. Cadmium telluride (CdTe)- and cadmium zinc telluride (CdZnTe)-based line scanners and small size two-dimensional X-ray sensors are emerging to the market, but the need for large-scale panels is axiomatic. In this study, a seamless CdTe tile was developed that enables the implementation of large-sized, energy selective X-ray detector panels. The developed tile consists of a 64 x 64 pixel array (with 150 mu m pitch) with a necessary substrate, ASIC, and CdTe crystal. The performance of the constructed seamless tile was characterized by focusing on spectral resolution and stability. In addition, a simple pixel trimming method that automates the equalization of each energy selective pixel was developed and analyzed. The obtained results suggest that the proposed concept of seamless (tileable) detector structures is a feasible approach to scale up panel sizes. The seamless tile shows comparable spectral resolution and stability performance with commercial CdTe sensors. The effect of tile to tile variation, the realization of a large-scale panel, as well as the charge sharing performance were left out of the scope and are to be studied in the next phase.Peer reviewe

Characterization of Seamless CdTe Photon Counting X-Ray Detector

Spectrally selective X-ray imaging provides improved material and tissue discrimination in comparison with the state-of-the-art dual energy technologies that are commonly used in medical, industrial, and security applications. Cadmium telluride (CdTe)- and cadmium zinc telluride (CdZnTe)-based line scanners and small size two-dimensional X-ray sensors are emerging to the market, but the need for large-scale panels is axiomatic. In this study, a seamless CdTe tile was developed that enables the implementation of large-sized, energy selective X-ray detector panels. The developed tile consists of a 64 x 64 pixel array (with 150 mu m pitch) with a necessary substrate, ASIC, and CdTe crystal. The performance of the constructed seamless tile was characterized by focusing on spectral resolution and stability. In addition, a simple pixel trimming method that automates the equalization of each energy selective pixel was developed and analyzed. The obtained results suggest that the proposed concept of seamless (tileable) detector structures is a feasible approach to scale up panel sizes. The seamless tile shows comparable spectral resolution and stability performance with commercial CdTe sensors. The effect of tile to tile variation, the realization of a large-scale panel, as well as the charge sharing performance were left out of the scope and are to be studied in the next phase.Peer reviewe

Fractionation of lead in soil by isotopic dilution and sequential extraction

‘Reactivity’ or ‘lability’ of lead is difficult to measure using traditional methods. We investigated the use of isotopic dilution with 204Pb to determine metal reactivity in four soils historically contaminated with contrasting sources of Pb, including (i) petrol-derived Pb, (ii) Pb/Zn minespoil, (iii) long-term sewage sludge application and (iv) 19th century urban waste disposal; total soil Pb concentrations ranged from 217 to 13 600 mg kg–1. A post-spike equilibration period of 3 days and suspension in 5.0 × 10–4 M ethylenediaminetetraacetic acid provided reasonably robust conditions for measuring isotopically exchangeable Pb. However, in acidic organic soils a dilute Ca(NO3)2 electrolyte may be preferable to avoid mobilisation of ‘non-labile’ Pb. Results showed that the reactive pool of soil Pb can be a large proportion of the total soil lead content but varies with the original Pb source. A comparison of isotopic exchangeability with the results of a sequential extraction procedure showed that (isotopically) ‘non-labile’ Pb may be broadly equated with ‘residual’ Pb in organic soils. However, in mineral soils the ‘carbonate’ and ‘oxide-bound’ Pb fractions included non-labile forms of Pb. The individual isotopic signatures of labile and non-labile Pb pools suggested that, despite prolonged contact with soil, differences between the lability of the original contaminant and the native soil Pb may remain