178 research outputs found

    Modeling the effect of workpiece temperature on micromagnetic high-speed-3MA-testing in case of AISI 4140

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    The growing trend towards industry 4.0 requires in-process identification of the surface properties. The non-destructive highspeed-3MA-testing can be used to characterize surface layers of ferrous materials during turning processes. However, in-process measurements will result in higher workpiece temperatures and thus would interfere with the micromagnetic properties of the workpiece. In the presented study, workpiece surface temperatures will be experimentally determined when turning AISI 4140. Further on, workpieces will be heated up to the respective temperatures, which will then be measured with the 3MA-sensor as they rotate. The effect of temperature will be modelled and used for compensating the associated errors

    The phosphatidylserine receptor from Hydra is a nuclear protein with potential Fe(II) dependent oxygenase activity

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    BACKGROUND: Apoptotic cell death plays an essential part in embryogenesis, development and maintenance of tissue homeostasis in metazoan animals. The culmination of apoptosis in vivo is the phagocytosis of cellular corpses. One morphological characteristic of cells undergoing apoptosis is loss of plasma membrane phospholipid asymmetry and exposure of phosphatidylserine on the outer leaflet. Surface exposure of phosphatidylserine is recognised by a specific receptor (phosphatidylserine receptor, PSR) and is required for phagocytosis of apoptotic cells by macrophages and fibroblasts. RESULTS: We have cloned the PSR receptor from Hydra in order to investigate its function in this early metazoan. Bioinformatic analysis of the Hydra PSR protein structure revealed the presence of three nuclear localisation signals, an AT-hook like DNA binding motif and a putative 2-oxoglutarate (2OG)-and Fe(II)-dependent oxygenase activity. All of these features are conserved from human PSR to Hydra PSR. Expression of GFP tagged Hydra PSR in hydra cells revealed clear nuclear localisation. Deletion of one of the three NLS sequences strongly diminished nuclear localisation of the protein. Membrane localisation was never detected. CONCLUSIONS: Our results suggest that Hydra PSR is a nuclear 2-oxoglutarate (2OG)-and Fe(II)-dependent oxygenase. This is in contrast with the proposed function of Hydra PSR as a cell surface receptor involved in the recognition of apoptotic cells displaying phosphatidylserine on their surface. The conservation of the protein from Hydra to human infers that our results also apply to PSR from higher animals

    Horizontal gene transfer contributed to the evolution of extracellular surface structures

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    The single-cell layered ectoderm of the fresh water polyp Hydra fulfills the function of an epidermis by protecting the animals from the surrounding medium. Its outer surface is covered by a fibrous structure termed the cuticle layer, with similarity to the extracellular surface coats of mammalian epithelia. In this paper we have identified molecular components of the cuticle. We show that its outermost layer contains glycoproteins and glycosaminoglycans and we have identified chondroitin and chondroitin-6-sulfate chains. In a search for proteins that could be involved in organising this structure we found PPOD proteins and several members of a protein family containing only SWT (sweet tooth) domains. Structural analyses indicate that PPODs consist of two tandem β-trefoil domains with similarity to carbohydrate-binding sites found in lectins. Experimental evidence confirmed that PPODs can bind sulfated glycans and are secreted into the cuticle layer from granules localized under the apical surface of the ectodermal epithelial cells. PPODs are taxon-specific proteins which appear to have entered the Hydra genome by horizontal gene transfer from bacteria. Their acquisition at the time Hydra evolved from a marine ancestor may have been critical for the transition to the freshwater environment

    Importance of Co-operative Hydrogen Bonding in the Apramycin-Ribosomal Decoding A-Site Interaction

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    An intramolecular hydrogen bond between the protonated equatorial 7'-methylamino group of apramycin and the vicinal axial 6'-hydroxy group acidifies the 6'-hydroxy group leading to a strong hydrogen bond to A1408 in the ribosomal drug binding pocket in the decoding A site of the small ribosomal subunit. In 6'-epiapramycin, the trans-nature of the 6'-hydroxy group and the 7'-methylamino group results in a much weaker intramolecular hydrogen bond, and a consequently weaker cooperative hydrogen bonding network with A1408, resulting overall in reduced inhibition of protein synthesis and antibacterial activity

    Power supply for battery charging

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    В системах энергоснабжения космических аппаратов очень много внимания уделяется системам заряда аккумуляторных батарей. В состав данных систем входят фотоэлектрические преобразователи, преобразующие энергию солнца в электрический ток. Данные преобразователи имеют крайне низкие энергетические показатели. Предлагаемая работа направлена на повышение эффективности заряда аккумуляторных батарей, посредством применения резонансного инвертора.In the space power systems, much attention is paid to battery charging systems. The composition of these systems includes photoelectric converters that convert the energy of the sun into electric current. These converters have extremely low energy performance. The proposed paper is aimed at increasing the efficiency of batteries chargers, by applying a resonant inverter

    Acoustic process monitoring in laser beam welding

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    Structure-borne acoustic emission (AE) measurement shows major advantages regarding quality assurance and process control in industrial applications. In this paper, laser beam welding of steel and aluminum was carried out under varying process parameters (welding speed, focal position) in order to provide data by means of structure-borne AE and simultaneously high-speed video recordings. The analysis is based on conventionally (e.g. filtering, autocorrelation, spectrograms) as well as machine learning methods (convolutional neural nets) and showed promising results with respect to the use of structure-borne AE for process monitoring using the example of spatter formation

    Treatment outcome definitions in nontuberculous mycobacterial pulmonary disease: an NTM-NET consensus statement

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    Nontuberculous mycobacterial pulmonary diseases (NTM-PD) are increasingly recognised as opportunistic infections of humans. These chronic pulmonary infections have two main presentations. The first is a fibro-cavitary disease, that occurs in patients with pre-existing pulmonary diseases, such as chronic obstructive pulmonary disease, bronchiectasis, previous tuberculosis or other structural lung disease. The second presentation is a nodular- bronchiectatic disease of primarily the lingula and middle lobe that tends to affect a middle- aged and elderly female population [1]. Treatment of NTM-PD requires long-term administration of complex multidrug therapies that are species-specific. Currently recommended regimens are supported by a very limited evidence base [2, 3]. The increasing incidence of NTM-PD has sparked increased interest in performing prospective randomised clinical trials [4]. One of the drawbacks of the existing case series and clinical trials is that they have applied different outcome measures [5]. This hampers meta-analyses, which are important in these still understudied infectious diseases. To enhance the quality and interpretability of the results of future trials and retrospective cohort studies, we aimed to formulate clear and broadly acceptable outcome definitions for NTM-PD treatment
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