102 research outputs found

    Method for upgrading a component within refurbishment

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    One of the arguments against an increased use of repair is that, due to the constantly growing progress, an often already outdated component would be restored. However, refurbishment also allows a component to be modified in order to upgrade it to the state of the art or to adapt it to changed requirements. Many existing approaches regarding Design for Upgradeability are based on a modular product architecture. In these approaches, however, only the upgradeability of a product is considered through the exchange of components. Nevertheless, the exchange and improvement of individual component regions within a refurbishment has already been successfully carried out using additive processes. In this paper, a general method is presented to support the reengineering process, which is necessary to refurbish and upgrade a damaged component. In order to identify which areas can be replaced in the closed system of a component, the systematics of the modular product architecture are used. This allows dependencies between functions and component regions to be identified. Thus, it possible to determine which functions can be integrated into the intended component

    Additive refurbishment of a vibration-loaded structural component

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    In the event of damage to additively manufactured components whose shape cannot be produced by machining, an additive repair can potentially be not only ecologically but also ecologically more favorable than the production of a new component. In addition, a number of hurdles that otherwise often impede the use of additive repair, e.g. the availability of the material of the damaged component for the additive process, are eliminated. As far as the authors are aware, this publication is the first to present a process for the additive refurbishment of additively manufactured components using the example of a wheel carrier. In this context, the possibility of increasing the fatigue strength of a structural component in refurbishment is discussed for the first time. To increase the fatigue strength of the wheel carrier, the chosen approach is to integrate the effect of particle damping into the component. Particularly in the case of components subjected to bending stresses, the effect of particle damping can be integrated into the component's interior without having to accept a significant loss of strength

    Plasmodium falciparum CRK4 directs continuous rounds of DNA replication during schizogony.

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    : Plasmodium parasites, the causative agents of malaria, have evolved a unique cell division cycle in the clinically relevant asexual blood stage of infection(1). DNA replication commences approximately halfway through the intracellular development following invasion and parasite growth. The schizont stage is associated with multiple rounds of DNA replication and nuclear division without cytokinesis, resulting in a multinucleated cell. Nuclei divide asynchronously through schizogony, with only the final round of DNA replication and segregation being synchronous and coordinated with daughter cell assembly(2,3). However, the control mechanisms for this divergent mode of replication are unknown. Here, we show that the Plasmodium-specific kinase PfCRK4 is a key cell-cycle regulator that orchestrates multiple rounds of DNA replication throughout schizogony in Plasmodium falciparum. PfCRK4 depletion led to a complete block in nuclear division and profoundly inhibited DNA replication. Quantitative phosphoproteomic profiling identified a set of PfCRK4-regulated phosphoproteins with greatest functional similarity to CDK2 substrates, particularly proteins involved in the origin of replication firing. PfCRK4 was required for initial and subsequent rounds of DNA replication during schizogony and, in addition, was essential for development in the mosquito vector. Our results identified an essential S-phase promoting factor of the unconventional P. falciparum cell cycle. PfCRK4 is required for both a prolonged period of the intraerythrocytic stage of Plasmodium infection, as well as for transmission, revealing a broad window for PfCRK4-targeted chemotherapeutics.<br/

    Asymmetric function theory

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    The classical theory of symmetric functions has a central position in algebraic combinatorics, bridging aspects of representation theory, combinatorics, and enumerative geometry. More recently, this theory has been fruitfully extended to the larger ring of quasisymmetric functions, with corresponding applications. Here, we survey recent work extending this theory further to general asymmetric polynomials.Comment: 36 pages, 8 figures, 1 table. Written for the proceedings of the Schubert calculus conference in Guangzhou, Nov. 201

    A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR

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    Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed

    Liver Transplantation because of Acute Liver Failure due to Heme Arginate Overdose in a Patient with Acute Intermittent Porphyria

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    In acute attacks of acute intermittent porphyria, the mainstay of treatment is glucose and heme arginate administration. We present the case of a 58-year-old patient with acute liver failure requiring urgent liver transplantation after erroneous 6-fold overdose of heme arginate during an acute attack. As recommended in the product information, albumin and charcoal were administered and hemodiafiltration was started, which could not prevent acute liver failure, requiring super-urgent liver transplantation after 6 days. The explanted liver showed no preexisting liver cirrhosis, but signs of subacute liver injury and starting regeneration. The patient recovered within a short time. A literature review revealed four poorly documented cases of potential hepatic and/or renal toxicity of hematin or heme arginate. This is the first published case report of acute liver failure requiring super-urgent liver transplantation after accidental heme arginate overdose. The literature and recommendations in case of heme arginate overdose are summarized. Knowledge of a potentially fatal course is important for the management of future cases. If acute liver failure in case of heme arginate overdose is progressive, super-urgent liver transplantation has to be evaluated

    Experience with short-period, small gap undulators at the SwissFEL aramis beamline

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    The SwissFEL Aramis beamline provides hard X-ray FEL radiation down to 1 Angström with 5.8 GeV and short period, 15mm, in-vacuum undulators (U15). To reach the maximum designed K-value of 1.8 the U15s have to be operated with vacuum gaps down to 3.0 mm. The thirteen-undulator modules are 4m long and each of them is equipped with a pair of permanent magnet quadrupoles at the two ends, aligned magnetically to the undulator axis. Optical systems and dedicated photon diagnostics are used to check the alignment and improve the K-value calibration. In this talk the main steps of the undulator commissioning will be recalled and a systematic comparison between the magnetic results and the electron and photon based measurements will be reported to highlight achievements and open issues.peer-reviewe

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Retinal Axonal Loss Begins Early in the Course of Multiple Sclerosis and Is Similar between Progressive Phenotypes

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    To determine whether retinal axonal loss is detectable in patients with a clinically isolated syndrome (CIS), a first clinical demyelinating attack suggestive of multiple sclerosis (MS), and examine patterns of retinal axonal loss across MS disease subtypes.Spectral-domain Optical Coherence Tomography was performed in 541 patients with MS, including 45 with high-risk CIS, 403 with relapsing-remitting (RR)MS, 60 with secondary-progressive (SP)MS and 33 with primary-progressive (PP)MS, and 53 unaffected controls. Differences in retinal nerve fiber layer (RNFL) thickness and macular volume were analyzed using multiple linear regression and associations with age and disease duration were examined in a cross-sectional analysis. In eyes without a clinical history of optic neuritis (designated as "eyes without optic neuritis"), the total and temporal peripapillary RNFL was thinner in CIS patients compared to controls (temporal RNFL by -5.4 µm [95% CI -0.9 to--9.9 µm, p = 0.02] adjusting for age and sex). The total (p = 0.01) and temporal (p = 0.03) RNFL was also thinner in CIS patients with clinical disease for less than 1 year compared to controls. In eyes without optic neuritis, total and temporal RNFL thickness was nearly identical between primary and secondary progressive MS, but total macular volume was slightly lower in the primary progressive group (p<0.05).Retinal axonal loss is increasingly prominent in more advanced stages of disease--progressive MS>RRMS>CIS--with proportionally greater thinning in eyes previously affected by clinically evident optic neuritis. Retinal axonal loss begins early in the course of MS. In the absence of clinically evident optic neuritis, RNFL thinning is nearly identical between progressive MS subtypes

    Integrated genome-wide chromatin occupancy and expression analyses identify key myeloid pro-differentiation transcription factors repressed by Myb

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    To gain insight into the mechanisms by which the Myb transcription factor controls normal hematopoiesis and particularly, how it contributes to leukemogenesis, we mapped the genome-wide occupancy of Myb by chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-Seq) in ERMYB myeloid progenitor cells. By integrating the genome occupancy data with whole genome expression profiling data, we identified a Myb-regulated transcriptional program. Gene signatures for leukemia stem cells, normal hematopoietic stem/progenitor cells and myeloid development were overrepresented in 2368 Myb regulated genes. Of these, Myb bound directly near or within 793 genes. Myb directly activates some genes known critical in maintaining hematopoietic stem cells, such as Gfi1 and Cited2. Importantly, we also show that, despite being usually considered as a transactivator, Myb also functions to repress approximately half of its direct targets, including several key regulators of myeloid differentiation, such as Sfpi1 (also known as Pu.1), Runx1, Junb and Cebpb. Furthermore, our results demonstrate that interaction with p300, an established coactivator for Myb, is unexpectedly required for Myb-mediated transcriptional repression. We propose that the repression of the above mentioned key pro-differentiation factors may contribute essentially to Myb’s ability to suppress differentiation and promote self-renewal, thus maintaining progenitor cells in an undifferentiated state and promoting leukemic transformation
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