94 research outputs found
Control of Uterine Microenvironment by Foxp3+ Cells Facilitates Embryo Implantation
Implantation of the fertilized egg into the maternal uterus depends on the fine balance between inflammatory and anti-inflammatory processes. Whilst regulatory T cells (Tregs) are reportedly involved in protection of allogeneic fetuses against rejection by the maternal immune system, their role for pregnancy to establish, e.g., blastocyst implantation, is not clear. By using 2-photon imaging we show that Foxp3(+) cells accumulated in the mouse uterus during the receptive phase of the estrus cycle. Seminal fluid further fostered Treg expansion. Depletion of Tregs in two Foxp3.DTR-based models prior to pairing drastically impaired implantation and resulted in infiltration of activated T effector cells as well as in uterine inflammation and fibrosis in both allogeneic and syngeneic mating combinations. Genetic deletion of the homing receptor CCR7 interfered with accumulation of Tregs in the uterus and implantation indicating that homing of Tregs to the uterus was mediated by CCR7. Our results demonstrate that Tregs play a critical role in embryo implantation by preventing the development of a hostile uterine microenvironment.DFG grants: (ZE526/4-2, SFB854TP7), Wilhelm Sander Stiftung Germany grant: (2009.022.1), Helmholtz Alliance for Immunotherapy, FCT, Medical Faculty Otto-von-Guericke University PhD grant
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Mitochondria Targeted Protein-Ruthenium Photosensitizer for Efficient Photodynamic Applications
Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity toward several cancerous cell lines. In particular, enhanced anticancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proliferation and clonogenicity occurs. Finally, attractive two-photon absorbing properties further underlined the great significance of this PS for mitochondria targeted PDT applications in deep tissue cancer therapy
Tribological system for cold sheet metal forming based on volatile lubricants and laser structured surfaces
AbschlussberichtA novel tribological system has been developed, in which volatile lubricants (carbon dioxide - CO2 or nitrogen- N2) are used as a substitute for mineral oil-based lubricants in deep drawing processes. This process enables the introduction of an intermediate medium under high pressure through flow-optimized, laser-drilled micro holes into the contact surfaces. This eliminates the need for subsequent, cost-intensive cleaning processes, as the volatile lubricants evaporate without leaving any residue during expansion to ambient pressure.
The design of initial micro hole geometries was based on simulations of the flow behaviour of the lubricants passing through, which in turn were validated using pressure reactor tests. In addition, the wetting behaviour of CO2 on relevant surfaces (tool surface and sheet material surface) was investigated experimentally using the captive-bubble-method. Thus, the optimal design of the micro holes (diameter, hole geometry and number of micro holes) could be determined using flat strip drawing tests. The optimal micro hole geometry determined in this way is suited for the use of both CO2 and N2 as volatile lubricant. Furthermore, extensive investigations for the production of the required micro hole geometry by laser drilling were carried out. The fundamentals for drilling micro holes in steel with high aspect ratios could be developed using an ultrashort pulsed research laser with very high pulse energy. Further experiments were conducted using an ultrashort pulsed prototype laser of the kW-class specially developed to increase productivity when drilling a multitude of micro holes with higher average laser power. The novel tribological system has been characterised by means of strip drawing tests and stretch bending tests. For both, CO2 (liquid) and N2 (gaseous), relatively low friction values could be achieved compared to conventional lubricants. It could be shown that deep drawing with both CO2 and N2 as dry lubricants is possible. Here, usage of the volatile lubricants not only allows the replacement of mineral oil based lubricants, but even improves the tribological system with regard to frictional forces in sheet metal forming. The feasibility of the new tribological system has been proven by performing deep drawing tests of rectangular cups. These tests showed a significantly enlarged process window of the forming process, which emphasise the tremendous potential of this new tribological system.12816
Making maps of cosmic microwave background polarization for B-mode studies: The POLARBEAR example
Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. For instance, in the context of ground-based observations, filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we have explicitly constructed a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigated the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then discuss the potential implications of these observations on the choice of map-making and power spectrum estimation approaches in the context of B-mode polarization studies. Specifically, we have studied the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may haveon the performance of the popular pseudo-spectrum estimators. We conclude that although maps produced by the proposed estimators arguably provide the most faithful representation of the sky possible given the data, they may not straightforwardly lead to the best constraints on the power spectra of the underlying sky signal and special care may need to be taken to ensure this is the case. By contrast, simplified map-makers which do not explicitly correct for time-domain filtering, but leave it to subsequent steps in the data analysis, may perform equally well and be easier and faster to implement. We focused on polarization-sensitive measurements targeting the B-mode component of the CMB signal and apply the proposed methods to realistic simulations based on characteristics of an actual CMB polarization experiment, POLARBEAR. Our analysis and conclusions are however more generally applicable. \ua9 ESO, 2017
Predictions of flavonoid solubility in ionic liquids by COSMO-RS: experimental verification, structural elucidation, and solvation characterization
Predictions of the solubility of flavonoids in a large variety of ionic liquids (ILs) with over 1800 available structures were examined based on COSMO-RS computation. The results show that the solubilities of flavonoids are strongly anion-dependent. Experimental measurement of the solubilities of esculin and rutin in 12 ILs with varying anions and cations show that predicted and experimental results generally have a good agreement. Based on the sound physical basis of COSMO-RS, the solubility changes of flavonoids were quantitatively associated with solvation interactions and structural characteristics of ILs. COSMO-RS derived parameters, i.e. misfit, H-bonding and van der Waals interaction energy, are shown to be capable of characterizing the complicated multiple interactions in the IL system effectively. H-bonding interaction is the most dominant interaction for ILs (followed by misfit and van der Waals interactions) to determine the solubility of flavonoids, and the anionic part has greater effect on the overall H-bonding capability of the IL. Based on basicity of anions, ILs were categorized into 3 groups, corresponding to the classification of the solubility of flavonoid. COSMO sigma-moment descriptors, which roughly denote the characteristic properties of the ILs, might be of general value to have a fast estimation for the solubilities of flavonoids as well as those compounds with massive moieties as H-bonding donors. The results obtained in this work may be important for achieving an improved understanding of IL solvations and the tailoring of the desired structures of ILs used as the media for efficient enzymatic esterification of flavonoids
Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles
We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles
Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles
We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles
Modulation of dendritic spine development and plasticity by BDNF and vesicular trafficking: fundamental roles in neurodevelopmental disorders associated with mental retardation and autism
The process of axonal and dendritic development establishes the synaptic circuitry of the central nervous system (CNS) and is the result of interactions between intrinsic molecular factors and the external environment. One growth factor that has a compelling function in neuronal development is the neurotrophin brain-derived neurotrophic factor (BDNF). BDNF participates in axonal and dendritic differentiation during embryonic stages of neuronal development, as well as in the formation and maturation of dendritic spines during postnatal development. Recent studies have also implicated vesicular trafficking of BDNF via secretory vesicles, and both secretory and endosomal trafficking of vesicles containing synaptic proteins, such as neurotransmitter and neurotrophin receptors, in the regulation of axonal and dendritic differentiation, and in dendritic spine morphogenesis. Several genes that are either mutated or deregulated in neurodevelopmental disorders associated with mental retardation have now been identified, and several mouse models of these disorders have been generated and characterized. Interestingly, abnormalities in dendritic and synaptic structure are consistently observed in human neurodevelopmental disorders associated with mental retardation, and in mouse models of these disorders as well. Abnormalities in dendritic and synaptic differentiation are thought to underlie altered synaptic function and network connectivity, thus contributing to the clinical outcome. Here, we review the roles of BDNF and vesicular trafficking in axonal and dendritic differentiation in the context of dendritic and axonal morphological impairments commonly observed in neurodevelopmental disorders associated with mental retardation
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