51 research outputs found

    Study of the wetting of coke by different pitches

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    Prebaked anodes are made of dry aggregates (coke, recycled butts and rejected green/baked anodes) and the binder pitch. During the mixing process, the wettability of coke by pitch influences the anode paste behavior. Coke particles (-125 +100 m) were prepared from the same source using two different procedures, and the wettability of cokes by five pitches with different properties was studied using a sessile-drop system at 170ÂşC. The contact angle results show that the wettability of coke by all pitches follows a similar trend for both cases, but the actual contact angles are different. The cokes and the pitch-coke interfaces were also investigated by the optical and scanning-electron microscopy (SEM) techniques. The image analysis results indicated that the coke particle size distribution depends on the coke preparation, which seems to influence its wettability

    A New Microsphere-Based Immunoassay for Measuring the Activity of Transcription Factors

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    There are several traditional and well-developed methods for analyzing the activity of transcription factors, such as EMSA, enzyme-linked immunosorbent assay, and reporter gene activity assays. All of these methods have their own distinct disadvantages, but none can analyze the changes in transcription factors in the few cells that are cultured in the wells of 96-well titer plates. Thus, a new microsphere-based immunoassay to measure the activity of transcription factors (MIA-TF) was developed. In MIA-TF, NeutrAvidin-labeled microspheres were used as the solid phase to capture biotin-labeled double-strand DNA fragments which contain certain transcription factor binding elements. The activity of transcription factors was detected by immunoassay using a transcription factor-specific antibody to monitor the binding with the DNA probe. Next, analysis was performed by flow cytometry. The targets hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-kappa B (NF-κB) were applied and detected in this MIA-TF method; the results that we obtained demonstrated that this method could be used to monitor the changes of NF-κB or HIF within 50 or 100 ng of nuclear extract. Furthermore, MIA-TF could detect the changes in NF-κB or HIF in cells that were cultured in wells of a 96-well plate without purification of the nuclear protein, an important consideration for applying this method to high-throughput assays in the future. The development of MIA-TF would support further progress in clinical analysis and drug screening systems. Overall, MIA-TF is a method with high potential to detect the activity of transcription factors

    Incentive or Habit Learning in Amphibians?

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    Toads (Rhinella arenarum) received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive values ranging from appetitive (deionized water, DW, leading to weight gain), to neutral (300 mM slightly hypertonic solution, leading to no net weight gain or loss), and aversive (800 mM highly hypertonic solution leading to weight loss). In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mM solutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization

    The N-Terminal Region of the PA Subunit of the RNA Polymerase of Influenza A/HongKong/156/97 (H5N1) Influences Promoter Binding

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    BACKGROUND: The RNA polymerase of influenza virus is a heterotrimeric complex of PB1, PB2 and PA subunits which cooperate in the transcription and replication of the viral genome. Previous research has shown that the N-terminal region of the PA subunit of influenza A/WSN/33 (H1N1) virus is involved in promoter binding. METHODOLOGY/PRINCIPAL FINDINGS: Here we extend our studies of the influenza RNA polymerase to that of influenza strains A/HongKong/156/97 (H5N1) and A/Vietnam/1194/04 (H5N1). Both H5N1 strains, originally isolated from patients in 1997 and 2004, showed significantly higher polymerase activity compared with two classical human strains, A/WSN/33 (H1N1) and A/NT/60/68 (H3N2) in vitro. This increased polymerase activity correlated with enhanced promoter binding. The N-terminal region of the PA subunit was the major determinant of this enhanced promoter activity. CONCLUSIONS/SIGNIFICANCE: Overall we suggest that the N-terminal region of the PA subunit of two recent H5N1 strains can influence promoter binding and we speculate this may be a factor in their virulence

    Quantification of sodium present in dry aggregates and anodes

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    In aluminum industry, it is important to determine the concentration of contaminants present in anode raw materials as rapidly as possible in order to adjust the anode recipe. Sodium, which is an impurity coming largely from anode butts, significantly influences the anode reactivity, and an increase in its concentration increases the anode consumption. A simple and inexpensive method was developed to quantify the sodium content in dry aggregates and anodes without grinding the samples. The method is based on potentiometric principles using a sodium-ion specific electrode. A sample can be analyzed easily within thirty minutes. In order to prevent the rapid degradation of the specific electrode due to experimental conditions, sodium is extracted from samples by electrophoresis prior to the test. The comparison shows that the measured sodium concentrations obtained are similar to the results determined by other test methods

    Gravitational-wave research as an emerging field in the Max Planck Society. The long roots of GEO600 and of the Albert Einstein Institute

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    On the occasion of the 50th anniversary since the beginning of the search for gravitational waves at the Max Planck Society, and in coincidence with the 25th anniversary of the foundation of the Albert Einstein Institute, we explore the interplay between the renaissance of general relativity and the advent of relativistic astrophysics following the German early involvement in gravitational-wave research, to the point when gravitational-wave detection became established by the appearance of full-scale detectors and international collaborations. On the background of the spectacular astrophysical discoveries of the 1960s and the growing role of relativistic astrophysics, Ludwig Biermann and his collaborators at the Max Planck Institute for Astrophysics in Munich became deeply involved in research related to such new horizons. At the end of the 1960s, Joseph Weber's announcements claiming detection of gravitational waves sparked the decisive entry of this group into the field, in parallel with the appointment of the renowned relativist Juergen Ehlers. The Munich area group of Max Planck institutes provided the fertile ground for acquiring a leading position in the 1970s, facilitating the experimental transition from resonant bars towards laser interferometry and its innovation at increasingly large scales, eventually moving to a dedicated site in Hannover in the early 1990s. The Hannover group emphasized perfecting experimental systems at pilot scales, and never developed a full-sized detector, rather joining the LIGO Scientific Collaboration at the end of the century. In parallel, the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) had been founded in Potsdam, and both sites, in Hannover and Potsdam, became a unified entity in the early 2000s and were central contributors to the first detection of gravitational waves in 2015.Comment: 94 pages. Enlarged version including new results from further archival research. A previous version appears as a chapter in the volume The Renaissance of General Relativity in Context, edited by A. Blum, R. Lalli and J. Renn (Boston: Birkhauser, 2020

    Exploring new physics frontiers through numerical relativity

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    The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

    The Confrontation between General Relativity and Experiment

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    Quality control via electrical resistivity measurement of industrial anodes

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    Aluminum production requires the use of carbon anodes. Anode quality influences strongly the cell stability, energy consumption, green house gas (GHG) emissions, and production cost. Current practice for anode quality evaluation (visual inspection and analysis of a core taken from the top of a small number of anodes produced) gives limited information. A simple and non-intrusive technique has been developed to measure the electrical resistivity distribution in industrial anodes with the objective of using it for on-line quality control in the paste plant to eliminate defective green anodes. This helps avoid the unnecessary baking of substandard anodes and reduces energy consumption and GHG emissions. The technology could ultimately be used also for baked anodes. The electrical resistivity is a distinctive characteristic of anode quality, and its distribution indicates anode homogeneity. In this article, the measurement technique will be explained and results will be presented which demonstrate its use for the determination of anode quality
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