Milieu-adopted in vitro and in vivo differentiation of mesenchymal tissues derived from different adult human CD34-negative progenitor cell clones

Adult mesenchymal stem cells with multilineage differentiation potentially exist in the bone marrow, but have also been isolated from the peripheral blood. The differentiation of stem cells after leaving their niches depends predominately on the local milieu and its new microenvironment, and is facilitated by soluble factors but also by the close cell-cell interaction in a three-dimensional tissue or organ system. We have isolated CD34-negative, mesenchymal stem cell lines from human bone marrow and peripheral blood and generated monoclonal cell populations after immortalization with the SV40 large T-antigen. The cultivation of those adult stem cell clones in an especially designed in vitro environment, including self-constructed glass capillaries with defined growth conditions, leads to the spontaneous establishment of pleomorphic three-dimensional cell aggregates ( spheroids) from the monoclonal cell population, which consist of cells with an osteoblast phenotype and areas of mineralization along with well-vascularized tissue areas. Modifications of the culture conditions favored areas of bone-like calcifications. After the transplantation of the at least partly mineralized human spheroids into different murine soft tissue sites but also a dorsal skinfold chamber, no further bone formation could be observed, but angiogenesis and neovessel formation prevailed instead, enabling the transplanted cells and cell aggregates to survive. This study provides evidence that even monoclonal adult human CD34-negative stem cells from the bone marrow as well as peripheral blood can potentially differentiate into different mesenchymal tissues depending on the local milieu and responding to the needs within the microenvironment. Copyright (C) 2005 S. Karger AG, Basel

Visualization of leukocyte transendothelial and interstitial migration using reflected light oblique transillumination in intravital video microscopy

Dynamic visualization of the intravascular events leading to the extravasation of leukocytes into tissues by intravital microscopy has significantly expanded our understanding of the underlying molecular processes. In contrast, the detailed observation of leukocyte transendothelial and interstitial migration in vivo has been hampered by the poor image contrast of cells within turbid media that is obtainable by conventional brightfield microscopy. Here we present a microscopic method, termed reflected light oblique transillumination microscopy, that makes use of the optical interference phenomena generated by oblique transillumination to visualize subtle gradients of refractive indices within tissues for enhanced image contrast. Using the mouse cremaster muscle, we demonstrate that this technique makes possible the reliable quantification of extravasated leukocytes as well as the characterization of morphological phenomena of leukocyte transendothelial and interstitial migration

Meta-surrogate benchmarking for hyperparameter optimization

Despite the recent progress in hyperparameter optimization (HPO), available benchmarks that resemble real-world scenarios consist of a few and very large problem instances that are expensive to solve. This blocks researchers and practitioners not only from systematically running large-scale comparisons that are needed to draw statistically significant results but also from reproducing experiments that were conducted before. This work proposes a method to alleviate these issues by means of a meta-surrogate model for HPO tasks trained on off-line generated data. The model combines a probabilistic encoder with a multi-task model such that it can generate inexpensive and realistic tasks of the class of problems of interest. We demonstrate that benchmarking HPO methods on samples of the generative model allows us to draw more coherent and statistically significant conclusions that can be reached orders of magnitude faster than using the original tasks. We provide evidence of our findings for various HPO methods on a wide class of problems

A Parameter Study of Classical Be Star Disk Models Constrained by Optical Interferometry

We have computed theoretical models of circumstellar disks for the classical Be stars $\kappa$ Dra, $\beta$ Psc, and $\upsilon$ Cyg. Models were constructed using a non-LTE radiative transfer code developed by \citet{sig07} which incorporates a number of improvements over previous treatments of the disk thermal structure, including a realistic chemical composition. Our models are constrained by direct comparison with long baseline optical interferometric observations of the H$\alpha$ emitting regions and by contemporaneous H$\alpha$ line profiles. Detailed comparisons of our predictions with H$\alpha$ interferometry and spectroscopy place very tight constraints on the density distributions for these circumstellar disks.Comment: 10 figures,28 pages, accepted by Ap

Decontamination of groundwater using membrane-assisted solvent extraction

This report describes the development of a new process to remove volatile organic compounds at dilute concentrations (VOCs) from groundwater was recently begun at Argonne. This process consists of membrane-assisted solvent extraction and membrane-assisted distillation stripping (MASX/MADS). The use of membranes is the solvent extraction and distillation stripping units improves mass transfer by increasing the interfacial surface area, thus allowing the process to be performed efficiently at high throughputs. The thermodynamics of the separation process and regions of applicability of this process are discussed

Decontamination of groundwater using membrane-assisted solvent extraction

This report describes the development of a new process to remove volatile organic compounds at dilute concentrations (VOCs) from groundwater was recently begun at Argonne. This process consists of membrane-assisted solvent extraction and membrane-assisted distillation stripping (MASX/MADS). The use of membranes is the solvent extraction and distillation stripping units improves mass transfer by increasing the interfacial surface area, thus allowing the process to be performed efficiently at high throughputs. The thermodynamics of the separation process and regions of applicability of this process are discussed