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Vein mineralization observed in boreholes, quarries and outcrops of Upper Permian and Mesozoic sediments in the Thuringian Syncline, Germany, was investigated for the first time by petrography, electron microprobe analysis and stable isotope analysis. The objective was a characterization of paleo-fluid systems within this basin. Veins are mostly restricted to NW-SE trending fault systems and comprise carbonates (calcite, dolomite), minor sulfates (gypsum/anhydrite, celestite, barite), and rarely sulfides. They are variably distributed within the Late Paleozoic to Mesozoic succession. Calcite vein mineralization occurs in almost all Triassic strata, though dominating in the Lower Muschelkalk subgroup (mu). Gypsum/anhydrite veins occur in the Middle Keuper subgroup (km), Middle Muschelkalk subgroup (mm), Middle and Upper Buntsandstein subgroup (sm, so) as well as in the Upper Permian (Zechstein). Sulfate and carbonate isotope analyses indicate that most vein mineralization dominantly crystallized from intraformational fluids within the Upper Permian and Triassic sediments. Crystallization from descending meteoric waters was observed especially for calcite veins in the Lower Muschelkalk, but also for gypsum/anhydrite veins in the Upper Buntsandstein. Mineralization from ascending, carbonate-pH-buffered, warm waters was restricted to individual parts of the southern, deep reaching main border fault zone of the Thuringian Syncline. Mixing and fault crossing fluid movements are subordinate within the Thuringian Syncline. We conclude that no large scale cross-formational fluid flow occurred in Thuringian Syncline over the last millions of years.

We extend a recent three-loop calculation of nuclear matter in chiral perturbation theory by including the effects from two-pion exchange with single and double virtual $\Delta(1232)$-isobar excitation. Regularization dependent short-range contributions from pion-loops are encoded in a few NN-contact coupling constants. The empirical saturation point of isospin-symmetric nuclear matter, $\bar E_0 = -16 $MeV, $\rho_0 = 0.16 $fm$^{-3}$, can be well reproduced by adjusting the strength of a two-body term linear in density (and weakening an emerging three-body term quadratic in density). The nuclear matter compressibility comes out as $K = 304 $MeV. The real single-particle potential $U(p,k_{f0})$ is substantially improved by the inclusion of the chiral $\pi N\Delta$-dynamics: it grows now monotonically with the nucleon momentum $p$. The effective nucleon mass at the Fermi surface takes on a realistic value of $M^*(k_{f0})=0.88M$. As a consequence of these features, the critical temperature of the liquid-gas phase transition gets lowered to the value $T_c \simeq 15 $MeV. In this work we continue the complex-valued single-particle potential $U(p,k_f)+i W(p,k_f)$ into the region above the Fermi surface $p>k_f$. The effects of $2\pi$-exchange with virtual $\Delta$-excitation on the nuclear energy density functional are also investigated. The effective nucleon mass associated with the kinetic energy density is $\widetilde M^*(\rho_0)= 0.64M$. Furthermore, we find that the isospin properties of nuclear matter get significantly improved by including the chiral $\pi N\Delta$-dynamics., Comment: 28 pages, 13 figures

We extend a recent three-loop calculation of nuclear matter in the systematic framework of chiral perturbation theory to finite temperatures T. The contributions from one- and two-pion exchange diagrams which cause nuclear binding and saturation at T=0 are included for T>0 in the density and temperature dependent free energy per particle, $\bar F(rho,T)$. The so-called anomalous 2pi-exchange contribution $\bar A(rho,T)$ (with no counterpart in the ground state energy density at T=0) is consistently included. The calculated pressure isotherms display the familiar first-order liquid-gas phase transition of isospin symmetric nuclear matter with a critical point at T_c = 25.5 MeV and rho_c = 0.09 fm^{-3}. The too high value of the critical temperature originates from the strong momentum dependence of the underlying single-particle potential U(p,k_{f0}) near the Fermi-surface. We also consider pure neutron matter at T>0 in the same framework and find fair agreement with sophisticated many-body calculations for neutron densities rho_n < 0.2 fm^{-3}., 10 pages, 4 figures, submitted to Physics Letters B

Using the two-loop approximation of chiral perturbation theory, we calculate the momentum and density dependent single particle potential of nucleons in isospin-symmetric nuclear matter. The contributions from one- and two-pion exchange diagrams give rise to a potential depth for a nucleon at rest of $U(0,k_{f0}) = -53.2 $MeV at saturation density. The momentum dependence of the real part of the single particle potential $U(p,k_{f0})$ is non-monotonic and can be translated into a mean effective nucleon mass of $\bar M^* \simeq 0.8 M$. The imaginary part of the single particle potential $W(p,k_f)$ is generated to that order entirely by iterated one-pion exchange. The resulting half width of a nucleon hole-state at the bottom of the Fermi sea comes out as $W(0,k_{f0})=29.7 $MeV. The basic theorems of Hugenholtz-Van-Hove and Luttinger are satisfied in our perturbative two-loop calculation of the nuclear mean field., Comment: 13 pages, 5 figures, submitted to Nuclear Physics A

Primary malignant melanoma of the esophagus is a rare but aggressive tumor that accounts for less than 0.1-0.2% of all esophageal malignancies. The aim of this study was to report a case of primary malignant melanoma of the esophagus in a 72-year-old woman. The diagnosis was histologically proven, but the patient died despite extensive surgical resection.

The structure and the microstructure of nickel manganite NTC thermistors have been determined and correlated with their electrical properties in order to understand the `ageing' phenomenon observed in these semiconductor devices. It has been shown that the heat treatment of metallization by serigraphy is responsible for structural and microstructural modifications. During this annealing some of the Ni 2+ cations migrate from the octahedral sites to the tetrahedral sites. At the same time, the ceramic is oxidized and precipitates of a cationic defect spinel phase appear. These modifications lead to a decrease in resistivity. During the ageing test at 125°C the cationic distribution does not change but the precipitates disappear. It induces an increase in resistivity. An improved serigraphy process is proposed to achieve stable NTC thermistors.

Believing that figural zoom invariance and the cross-figural boundary linking implied by medial loci are important aspects of object shape, we present the mathematics of and algorithms for the extraction of medial loci directly from image intensities. The medial loci called cores are defined as generalized maxima in scale space of a form of medial information that is invariant to translation, rotation, and, in particular, zoom. These loci are very insensitive to image disturbances, in strong contrast to previously available medial loci, as demonstrated in a companion paper. Core-related geometric properties and image object representations are laid out which, together with the aforementioned insensitivities, allow the core to be used effectively for a variety of image analysis objectives.

With the view of understanding the electrical conduction mechanism in the nickel-copper manganite spinels, the cation distribution and the ionic configurations of these compounds have been established by associating powder neutron diffraction, thermogravimetric measurements and XPS spectroscopy analysis. Neutron diffraction measurements allow us to reach the scattering lengths in both tetrahedral and octahedral sites. From this information we deduce lower and upper limits for the different cation fractions in both sites. The XPS spectroscopy analysis shows a predominately divalent copper, localized in tetrahedral sites. The monovalent copper is also present, but at a much smaller content. The additional information supplied by Mn 2+ tetrahedral thermogravimetric measurements resolves the cation distribution in these compounds. Finally, the discussion of the electrical properties using these structural formulas has shown that the presence of copper probably induces a mean-range hopping, the average distance of jumps being estimated to ≈ 9 A.

Purpose: The purpose of this investigation was to develop methods and software for computing realistic digitally reconstructed electronic portal images with known setup errors for use as benchmark test cases for evaluation and intercomparison of computer-based methods for image matching and detecting setup errors in electronic portal images. Methods and Materials: An existing software tool for computing digitally reconstructed radiographs was modified to compute simulated megavoltage images. An interface was added to allow the user to specify which setup parameter(s) will contain computer-induced random and systematic errors in a reference beam created during virtual simulation. Other software features include options for adding random and structured noise, Gaussian blurring to simulate geometric unsharpness, histogram matching with a "typical" electronic portal image, specifying individual preferences for the appearance of the "gold standard" image, and specifying the number of images generated. The visible male computed tomography data set from the National Library of Medicine was used as the planning image. Results: Digitally reconstructed electronic portal images with known setup errors have been generated and used to evaluate our methods for automatic image matching and error detection. Any number of different sets of test cases can be generated to investigate setup errors involving selected setup parameters and anatomic volumes. This approach has proved to be invaluable for determination of error detection sensitivity under ideal (rigid body) conditions and for guiding further development of image matching and error detection methods. Example images have been successfully exported for similar use at other sites. Conclusions: Because absolute truth is known, digitally reconstructed electronic portal images with known setup errors are well suited for evaluation of computer-aided image matching and error detection methods. High-quality planning images, such as the visible human CT scans from the National Library of Medicine, are essential for producing realistic images. Sets of test cases with systematic and random errors in seelcted setup parameters and anatomic volumes are suitable for use as standard benchmarks by the radiotherapy community. In addition to serving as an aid to research and development, benchmark images may also be useful for evaluation of commercial systems and as part of a quality assurance program for clinical systems. Test cases and software are available upon request.

PURPOSE Portal imaging is the most important quality assurance procedure for monitoring the reproducibility of setup geometry in radiation therapy. The role of portal imaging has become even more critical in recent years due to the migration of three-dimensional (3D) treatment planning technology, including high-precision conformal therapy, from the research setting to routine clinical practice. Unfortunately, traditional methods for acquiring and interpreting portal images suffer from a number of deficiencies that contribute to the well-documented observation that many setup errors go undetected, and some persist for a clinically significant portion of the prescribed dose. Significant improvements in both accuracy and efficiency of detecting setup errors can, in principle, be achieved by using automatic image registration for on-line screening of images obtained from electronic portal imaging devices (EPIDs). METHODS AND MATERIALS This article presents recent developments in a method called core-based image analysis that shows great promise for achieving the desired improvements in error detection. Core-based image analysis is a fundamental computer vision method that is capable of exploiting the full power of EPIDs by providing for on-line detection of setup errors via automatic registration of user-selected anatomical structures. We describe a robust method for automatic portal image registration based on core analysis and demonstrate an approach for assessing both accuracy and precision of registration methods using realistic, digitally reconstructed portal radiographs (DRPRs) where truth is known. RESULTS Automatic core-based analysis of a set of 20 DRPRs containing known, random field positioning errors was performed for a patient undergoing treatment for prostate cancer. In all cases, the reported translation was within 1 mm of the actual translation with mean absolute errors of 0.3 mm and standard deviations of 0.3 mm. In all cases, the reported rotation was within 0.6 degree of the actual rotation with a mean absolute error of 0.18 degree and a standard deviation of 0.23 degree. CONCLUSION Our results, using digitally reconstructed portal radiographs that closely resemble clinical portal images, suggest that automatic core-based registration is suitable as an on-line screening tool for detecting and quantifying patient setup errors.

The multiscale medial axis (MMA) is a principled means of describing both the spatial and width properties of objects in grey-scale images. We describe its computation and provide an example of its use in an image registration task.

Laparoscopic surgery has gained wide acceptance. However, there is still debate as to its role in assessment and staging of gastrointestinal malignancies(1)since it may promote dissemination of cancer cells.(2)We report the first case of a low-grade mesenteric nodal lymphoma for laparoscopic hernia repair, complicated by distant implants both on the peritoneum and wall mesh.