574 research outputs found

    Ensemble averaging of acoustic data

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    A computer program called Ensemble Averaging of Acoustic Data is documented. The program samples analog data, analyzes the data, and displays them in the time and frequency domains. Hard copies of the displays are the program's output. The documentation includes a description of the program and detailed user instructions for the program. This software was developed for use on the Ames 40- by 80-Foot Wind Tunnel's Dynamic Analysis System consisting of a PDP-11/45 computer, two RK05 disk drives, a tektronix 611 keyboard/display terminal, and FPE-4 Fourier Processing Element, and an analog-to-digital converter

    Spin chain from membrane and the Neumann-Rosochatius integrable system

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    We find membrane configurations in AdS_4 x S^7, which correspond to the continuous limit of the SU(2) integrable spin chain, considered as a limit of the SU(3) spin chain, arising in N=4 SYM in four dimensions, dual to strings in AdS_5 x S^5. We also discuss the relationship with the Neumann-Rosochatius integrable system at the level of Lagrangians, comparing the string and membrane cases.Comment: LaTeX, 16 pages, no figures; v2: 17 pages, title changed, explanations and references added; v3: more explanations added; v4: typos fixed, to appear in Phys. Rev.

    Inhibition of the activity of pro-inflammatory secretory phospholipase A2 by acute phase proteins

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    Pro-Inflammatory non-pancreatic phospholipase A2 (sPLA2) is markedly over-expressed in acute systemic and chronic local inflammatory processes. Since in acute phase reaction sPLA2 is often over-expressed simultaneously with acute phase proteins (APP), it is important to determine whether APP interacts with sPLA2. We tested ten APPs for interaction with sPLA2 using as a substrate multilamellar Hposomes composed either of PC:Lyso PC or PE:Lyso PE. Using PC:Lyso PC substrate, CRP, lactoferrin and SAP were found to inhibit sPLA2 activity with an IC50 of 25 μg/ml, 7.5 μg/ml and 50 μg/ml, respectively, corresponding to 0.21 μM, 0.1 μM and 0.21 μM respectively. Using PE:Lyso PE substrate only SAP was inhibitory, with an IC50 of 10 μg/ml (0.04 μM). Phosphorylcholine abolished the inhibitory activity of CRP but not of SAP or lactoferrin. Addition of phosphorylethanolamine or of excess calcium had no effect on the inhibitory activity of APP. Limulin, lysozyme, transferrin, β2-microglobulin, α2-macroglobulin, human and bovine albumins had no effect on sPLA2 activity. Therefore neither the structure of pentraxins, or ironbinding, bacteriostatic property or amyloidogenic property preclude whether APP modulates sPLA2 activity. Inhibition of pro-inflammatory sPLA2 by APP may be one of the protective mechanisms of the acute phase reaction

    Ruminal metabolism of ammonia N and rapeseed meal soluble N fraction

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    The present study was conducted to investigate ruminal N metabolism in dairy cows using N-15 labeled N sources [ammonia N (AN), soluble non-ammonia N (SNAN) from rapeseed meal, and insoluble nonammonia N (NAN) from rapeseed meal]. To describe the observed pattern of N-15 transactions in the rumen, dynamic compartmental models were developed. The experiment consisted of 3 experimental treatments allocated to 4 cows according to a changeover design. The results from 2 treatments (AN and rapeseed meal SNAN) are reported in this paper. Ammonia N and rapeseed SNAN, both labeled with N-15, were administered intraruminally. Rumen evacuations in combination with grab samples from the rumen contents were used to determine ruminal N pool sizes. The N-15-atom% excess was determined in N fractions of rumen digesta samples that were distributed between 0 and 82 h after dosing. For the AN treatment, a 2-compartment model was developed to describe the observed pattern in N-15-atom% excess pool sizes of AN and bacterial NJ and to estimate kinetic parameters of ruminal N-15 transactions. For the SNAN treatment, an additional compartment of SNAN was included in the model. Model simulations were used to estimate N fluxes in the rumen. Both models described the observed pattern of N-15-atom% excess pool sizes accurately, based on small residuals between observed and predicted values. Immediate increases in N-15-atom% excess of bacterial N with AN treatment suggested that microbes absorbed AN from extracellular pools rapidly to maintain sufficient intracellular concentrations. Proportionally 0.69 of the AN dose was recovered as NAN flow from the rumen. A rapid disappearance of labeled SNAN from rumen fluid and appearance in bacterial N pool indicated that, proportionally, 0.56 of SNAN was immediately either adsorbed to bacterial cell surfaces or taken up to intracellular pools. Immediate uptake of labeled SNAN was greater than that of AN (proportionally 0.56 vs. 0.16 of the dose). Degradation rate of SNAN to AN was relatively slow (0.46/h), but only 0.08 of the SNAN dose was estimated to escape ruminal degradation because of rapid uptake by the bacteria. Overall, losses of the N-15 dose as AN absorption and outflow from the rumen were higher (P <0.01) for the AN than the SNAN treatment (0.31 and 0.11 of the dose, respectively). Consequently, recovery as NAN flow was greater for SNAN than for AN treatment (0.89 vs. 0.69 of the dose). Estimated rate of bacterial N recycling to AN was on average 0.006/h, which suggests that N losses due to intraruminal recycling are small in dairy cows fed at high intake levels. We conclude that SNAN isolated from rapeseed meal had better ruminal N utilization efficiency than AN, as indicated by smaller rurninal N losses as AN (0.11 vs. 0.31 of the dose) and greater bacterial N flow (0.81 vs. 0.69 of the dose). Furthermore, the current findings indicate that rapid adsorption of soluble proteins to bacterial cells plays an important role in ruminal N metabolism.Peer reviewe

    Ruminal metabolism of ammonia N and rapeseed meal soluble N fraction

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    The present study was conducted to investigate ruminal N metabolism in dairy cows using N-15 labeled N sources [ammonia N (AN), soluble non-ammonia N (SNAN) from rapeseed meal, and insoluble nonammonia N (NAN) from rapeseed meal]. To describe the observed pattern of N-15 transactions in the rumen, dynamic compartmental models were developed. The experiment consisted of 3 experimental treatments allocated to 4 cows according to a changeover design. The results from 2 treatments (AN and rapeseed meal SNAN) are reported in this paper. Ammonia N and rapeseed SNAN, both labeled with N-15, were administered intraruminally. Rumen evacuations in combination with grab samples from the rumen contents were used to determine ruminal N pool sizes. The N-15-atom% excess was determined in N fractions of rumen digesta samples that were distributed between 0 and 82 h after dosing. For the AN treatment, a 2-compartment model was developed to describe the observed pattern in N-15-atom% excess pool sizes of AN and bacterial NJ and to estimate kinetic parameters of ruminal N-15 transactions. For the SNAN treatment, an additional compartment of SNAN was included in the model. Model simulations were used to estimate N fluxes in the rumen. Both models described the observed pattern of N-15-atom% excess pool sizes accurately, based on small residuals between observed and predicted values. Immediate increases in N-15-atom% excess of bacterial N with AN treatment suggested that microbes absorbed AN from extracellular pools rapidly to maintain sufficient intracellular concentrations. Proportionally 0.69 of the AN dose was recovered as NAN flow from the rumen. A rapid disappearance of labeled SNAN from rumen fluid and appearance in bacterial N pool indicated that, proportionally, 0.56 of SNAN was immediately either adsorbed to bacterial cell surfaces or taken up to intracellular pools. Immediate uptake of labeled SNAN was greater than that of AN (proportionally 0.56 vs. 0.16 of the dose). Degradation rate of SNAN to AN was relatively slow (0.46/h), but only 0.08 of the SNAN dose was estimated to escape ruminal degradation because of rapid uptake by the bacteria. Overall, losses of the N-15 dose as AN absorption and outflow from the rumen were higher (P <0.01) for the AN than the SNAN treatment (0.31 and 0.11 of the dose, respectively). Consequently, recovery as NAN flow was greater for SNAN than for AN treatment (0.89 vs. 0.69 of the dose). Estimated rate of bacterial N recycling to AN was on average 0.006/h, which suggests that N losses due to intraruminal recycling are small in dairy cows fed at high intake levels. We conclude that SNAN isolated from rapeseed meal had better ruminal N utilization efficiency than AN, as indicated by smaller rurninal N losses as AN (0.11 vs. 0.31 of the dose) and greater bacterial N flow (0.81 vs. 0.69 of the dose). Furthermore, the current findings indicate that rapid adsorption of soluble proteins to bacterial cells plays an important role in ruminal N metabolism.Peer reviewe

    Magnon-Like Dispersion Relation from M-Theory

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    We investigate classical rotating membranes in two different backgrounds. First, we obtain membrane solution in AdS4×S7AdS_4\times S^7 background, analogous to the solution obtained by Hofman and Maldacena in the case of string theory. We find a magnon type dispersion relation similar to that of Hofman and Maldacena and to the one found by Dorey for the two spin case. In the appendix of the paper, we consider membrane solutions in AdS7×S4AdS_7\times S^4, which give new relations between the conserved charges.Comment: 16 pages, typos corrected; V3: New section and comments added, to appear in Nucl. Phys.

    Highly Dynamic AC Current Control for Modular Multilevel Converters

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    A highly robust and dynamic control of the MMC grid currents is necessary to ensure grid stability. Based on a state space modelling of the MMC, a real time capable indirect modelbased control is presented. Measurements with a laboratory setup show the reliability even under disturbed grid conditions

    Synchronous motion of two vertically excited planar elastic pendula

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    The dynamics of two planar elastic pendula mounted on the horizontally excited platform have been studied. We give evidence that the pendula can exhibit synchronous oscillatory and rotation motion and show that stable in-phase and anti-phase synchronous states always co-exist. The complete bifurcational scenario leading from synchronous to asynchronous motion is shown. We argue that our results are robust as they exist in the wide range of the system parameters.Comment: Submitte

    Tenidap sodium inhibits secretory non-pancreatic phospholipase A2 synthesis by foetal rat calvarial osteoblasts

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    Tenidap (TD) was initially defined as a dual inhibitor of cyclooxygenase and lipoxygenase. This study was designed to assess its inhibitory activity against proinflammatory phospholipase A2. This study shows that TD inhibits the synthesis of pro-inflammatory secretory non-pancreatic phospholipase A2 (sPLA2). Concentrations as low as 0.25 μg/ml (0.725 μM) reduced the release of sPLA2 by 40% from foetal rat calvarial osteoblasts stimulated with IL-1β and TNFα, whereas a concentration of 2.5 μg/ml (7.25 μM) reduced the release by over 80%. TD also markedly reduced the release of sPLA2 from unstimulated cells. There was no direct inhibition of sPLA2 enzymatic activity by TD in vitro. Northern blot analysis showed that TD did not affect the sPLA2 mRNA levels; however, immunoblotting showed a dose-dependent reduction in sPLA2 enzyme. These results, together with a marked reduction in sPLA2 enzymatic activity, suggest that TD inhibits sPLA2 synthesis at the post-transcriptional level. Therefore TD seems to inhibit the arachidonic acid cascade proximally to cyclooxygenase and lipoxygenase and its anti-inflammatory activity may be related at least in part to the inhibition of sPLA2 synthesis
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