172 research outputs found

    Applicability of fluidic controls to a Rankine cycle automotive engine Final report

    Get PDF
    Fluidic controls for automotive engine examined by Rankine cycle performance with water, CP-34, and freon TF and investigation for boiler and feed pump control criteri

    The positive impact of agile retrospectives on the collaboration of distributed development teams – A practical approach on the example of Bosch engineering GmbH

    Get PDF
    To counteract competitive pressure, increasing customer requirements and growing product complexity successful distributed collaboration in product development is vital. Companies have to face new challenges, such as efficiency losses in communication. To overcome these challenges agile working practices, such as agile retrospectives, could be beneficial. The objective of this scientific work is to evaluate the benefit of agile working practices on the example of agile retrospectives, for the improvement of collaboration in distributed development teams. Based on literature analysis, qualitative and quantitative expert interviews following the DRM by Blessing and Chakrabarti, this scientific work shows that agile working practices have a high potential to improve distributed collaboration. To address this potential, several virtual agile retrospectives are developed and conducted within a distributed team at Bosch Engineering GmbH. The evaluation of this approach results in a high potential of agile retrospectives indicating an improvement tendency. Especially iteratively implemented virtual agile retrospectives have a positive impact on successful distributed collaboration

    The vascular bone marrow niche influences outcome in chronic myeloid leukemia via the E-selectin - SCL/TAL1-CD44 axis.

    Get PDF
    The endosteal bone marrow niche and vascular endothelial cells provide sanctuaries for leukemic cells. In murine chronic myeloid leukemia (CML) CD44 on leukemia cells and E-selectin on bone marrow endothelium are essential mediators for the engraftment of leukemic stem cells. We hypothesized that non-adhesion of CML-initiating cells to E-selectin on the bone marrow endothelium may lead to superior eradication of leukemic stem cells in CML after treatment with imatinib than imatinib alone. Indeed, here we show that treatment with the E-selectin inhibitor GMI-1271 in combination with imatinib prolongs survival of mice with CML via decreased contact time of leukemia cells with bone marrow endothelium. Non-adhesion of BCR-ABL1(+) cells leads to an increase of cell cycle progression and an increase of expression of the hematopoietic transcription factor and proto-oncogene Scl/Tal1 in leukemia-initiating cells. We implicate SCL/TAL1 as an indirect phosphorylation target of BCR-ABL1 and as a negative transcriptional regulator of CD44 expression. We show that increased SCL/TAL1 expression is associated with improved outcome in human CML. These data demonstrate the BCR-ABL1-specific, cell-intrinsic pathways leading to altered interactions with the vascular niche via the modulation of adhesion molecules - which could be exploited therapeutically in the future

    Synthesis and Characterisation of Hierarchically Structured Titanium Silicalite‐1 Zeolites with Large Intracrystalline Macropores

    Get PDF
    The successful synthesis of hierarchically structured titanium silicalite‐1 (TS‐1) with large intracrystalline macropores by steam‐assisted crystallisation of mesoporous silica particles is reported. The macropore topology was imaged in 3D by using electron tomography and synchrotron radiation‐based ptychographic X‐ray computed tomography, revealing interconnected macropores within the crystals accounting for about 30 % of the particle volume. The study of the macropore formation mechanism revealed that the mesoporous silica particles act as a sacrificial macropore template during the synthesis. Silicon‐to‐titanium ratio of the macroporous TS‐1 samples was successfully tuned from 100 to 44. The hierarchically structured TS‐1 exhibited high activity in the liquid phase epoxidation of 2‐octene with hydrogen peroxide. The hierarchically structured TS‐1 surpassed a conventional nano‐sized TS‐1 sample in terms of alkene conversion and showed comparable selectivity to the epoxide. The flexible synthesis route described here can be used to prepare hierarchical zeolites with improved mass transport properties for other selective oxidation reactions

    Precise Spatiotemporal Control of Optogenetic Activation Using an Acousto-Optic Device

    Get PDF
    Light activation and inactivation of neurons by optogenetic techniques has emerged as an important tool for studying neural circuit function. To achieve a high resolution, new methods are being developed to selectively manipulate the activity of individual neurons. Here, we report that the combination of an acousto-optic device (AOD) and single-photon laser was used to achieve rapid and precise spatiotemporal control of light stimulation at multiple points in a neural circuit with millisecond time resolution. The performance of this system in activating ChIEF expressed on HEK 293 cells as well as cultured neurons was first evaluated, and the laser stimulation patterns were optimized. Next, the spatiotemporally selective manipulation of multiple neurons was achieved in a precise manner. Finally, we demonstrated the versatility of this high-resolution method in dissecting neural circuits both in the mouse cortical slice and the Drosophila brain in vivo. Taken together, our results show that the combination of AOD-assisted laser stimulation and optogenetic tools provides a flexible solution for manipulating neuronal activity at high efficiency and with high temporal precision

    The proteasome inhibitor MG-132 sensitizes PC-3 prostate cancer cells to ionizing radiation by a DNA-PK-independent mechanism

    Get PDF
    BACKGROUND: By modulating the expression levels of specific signal transduction molecules, the 26S proteasome plays a central role in determining cell cycle progression or arrest and cell survival or death in response to stress stimuli, including ionizing radiation. Inhibition of proteasome function by specific drugs results in cell cycle arrest, apoptosis and radiosensitization of many cancer cell lines. This study investigates whether there is also a concomitant increase in cellular radiosensitivity if proteasome inhibition occurs only transiently before radiation. Further, since proteasome inhibition has been shown to activate caspase-3, which is involved in apoptosis, and caspase-3 can cleave DNA-PKcs, which is involved in DNA-double strand repair, the hypothesis was tested that caspase-3 activation was essential for both apoptosis and radiosensitization following proteasome inhibition. METHODS: Prostate carcinoma PC-3 cells were treated with the reversible proteasome inhibitor MG-132. Cell cycle distribution, apoptosis, caspase-3 activity, DNA-PKcs protein levels and DNA-PK activity were monitored. Radiosensitivity was assessed using a clonogenic assay. RESULTS: Inhibition of proteasome function caused cell cycle arrest and apoptosis but this did not involve early activation of caspase-3. Short-time inhibition of proteasome function also caused radiosensitization but this did not involve a decrease in DNA-PKcs protein levels or DNA-PK activity. CONCLUSION: We conclude that caspase-dependent cleavage of DNA-PKcs during apoptosis does not contribute to the radiosensitizing effects of MG-132

    On the origin of glioma

    Get PDF
    Glioma is the most frequent primary brain tumor of adults that has a presumably glial origin. Although our knowledge regarding molecular mechanisms and signaling pathways involved in gliomagenesis has increased immensely during the past decade, high-grade glioma remains a lethal disease with dismal prognosis. The failure of current therapies has to a large extent been ascribed the functional heterogeneity of glioma cells. One reason for this heterogeneity is most certainly the large number of variations in genetic alterations that can be found in high-grade gliomas. Another factor that may influence glioma heterogeneity could be the cell type from which the glioma is initiated. The cell of origin for glioma is still undefined, and additional knowledge about this issue may prove critical for a more complete understanding of glioma biology. Based on information from patients, developmental biology, and experimental glioma models, the most putative target cells include astrocytes, neural stem cells, and oligodendrocyte precursor cells, which are all discussed in more detail in this article. Animal modeling of glioma suggests that these three cell types have the capability to be the origin of glioma, and we have reason to believe that, depending on the initiating cell type, prognosis and response to therapy may be significantly different. Thus, it is essential to explore further the role of cellular origin in glioma

    Experimental traumatic brain injury

    Get PDF
    Traumatic brain injury, a leading cause of death and disability, is a result of an outside force causing mechanical disruption of brain tissue and delayed pathogenic events which collectively exacerbate the injury. These pathogenic injury processes are poorly understood and accordingly no effective neuroprotective treatment is available so far. Experimental models are essential for further clarification of the highly complex pathology of traumatic brain injury towards the development of novel treatments. Among the rodent models of traumatic brain injury the most commonly used are the weight-drop, the fluid percussion, and the cortical contusion injury models. As the entire spectrum of events that might occur in traumatic brain injury cannot be covered by one single rodent model, the design and choice of a specific model represents a major challenge for neuroscientists. This review summarizes and evaluates the strengths and weaknesses of the currently available rodent models for traumatic brain injury
    corecore