Nonlinear dynamic analysis of gas turbine combustor leaf seal

The leaf seals are one of the typical sealing systems in gas turbine and jet engines. In Baker Hughes LT family gas turbines, they are used to create sealing between the combustion chamber and the first stage nozzle. The leaf seals are thin metallic plates and subjected to dynamic loads and high temperatures. They have curved contacts, and depending on the inclination, they can experience partial contact. Furthermore, when excited by dynamic loads, the leaf seal can be subject to intermittent contact, possibly triggering wear out or vibratory phenomena. Due to its flexibility and its partial seating, it exhibits a complex nonlinear dynamic behaviour, strongly variable with the operating conditions. This study presents a numerical investigation using coupled static/dynamic harmonic balance method (HBM) frequency-based solution technique. The reported solutions include nonlinear forced response and contact studies for various operating and kinematic conditions along with brief insights

A Neutral and Stable Macrocyclic Mn(II) Complex for MRI Tumor Visualization

A stable and inert amphiphilic Mn(II) complex based on a bisamide derivative of 1,4-DO2A (DO2A=tetraazacyclododecane-1,4-diacetic acid) was synthesized and its H-1 NMR relaxometric behavior was investigated as a function of the magnetic field strength, pH and temperature. The interaction with human serum albumin (HSA) was also studied via relaxometry showing a good relaxivity enhancement at low field (at 1T and 298 K the relaxivity increases from 4.5 mM(-1) s(-1) of the Mn(II)-complex to 14.0 mM(-1) s(-1) of the complex-HSA supramolecular adduct). In vivo biodistribution and MRI studies highlighted a rapid and mixed renal/liver elimination without spleen accumulation from healthy mice and good contrast enhancing properties in a breast tumor murine model. A comparison with a clinically approved Gd(III) agent (GdBOPTA, Multihance (R)) underlined that the proposed Mn(II) contrast agent gave comparable tumor contrast enhancement up to 3 hours post-injection

Intranasal peptide-induced tolerance and linked suppression: consequences of complement deficiency.

A role for complement, particularly the classical pathway, in the regulation of immune responses is well documented. Deficiencies in C1q or C4 predispose to autoimmunity, while deficiency in C3 affects the suppression of contact sensitization and generation of oral tolerance. Complement components including C3 have been shown to be required for both B-cell and T-cell priming. The mechanisms whereby complement can mediate these diverse regulatory effects are poorly understood. Our previous work, using the mouse minor histocompatibility (HY) model of skin graft rejection, showed that both C1q and C3 were required for the induction of tolerance following intranasal peptide administration. By comparing tolerance induction in wild-type C57BL/6 and C1q-, C3-, C4- and C5-deficient C57BL/6 female mice, we show here that the classical pathway components including C3 are required for tolerance induction, whereas C5 plays no role. C3-deficient mice failed to generate a functional regulatory T (Treg) -dendritic cell (DC) tolerogenic loop required for tolerance induction. This was related to the inability of C3-deficient DC to up-regulate the arginine-consuming enzyme, inducible nitric oxide synthase (Nos-2), in the presence of antigen-specific Treg cells and peptide, leading to reduced Treg cell generation. Our findings demonstrate that the classical pathway and C3 play a critical role in the peptide-mediated induction of tolerance to HY by modulating DC function

Development of a tomato pomace biorefinery based on a CO2-supercritical extraction process for the production of a high value lycopene product, bioenergy and digestate

Tomato peels and seeds (TP) are the most abundant canning industry waste actually used to produce biogas. TP is rich in lycopene (lyc) and represent a more sustainable feedstock than tomato fruits actually employed. It was therefore chosen as feedstock together with supercritical CO2 extraction (SFE-CO2) technology to develop a TP-SFE-CO2 biorefinery, topic scarcely investigated. Two TP were tested and although TP-SFE-CO2 parameters were the same, lyc recoveries depended by peel structure changes occurred during pre -SFE-CO2 drying step. Higher moisture (102.7 g kg-1 wet weight) permitted 97 % lyc recovery and gave a water-in-oil emulsion as extract. Mass balance confirmed that lyc isomerisation did not cause lyc losses. After a significant oil extraction, exhaust TP showed a biodegradability 64% higher than the raw one, attributable to fibre structure disruption. The biorefinery proposed (SFE_CO2+anaerobic digestion) determined positive economic revenue (+787.9 \u20ac t-1 TP) on the contrary of the actual TP management

Effect of irradiation/bone marrow transplantation on alveolar epithelial type II cells is aggravated in surfactant protein D deficient mice.

Irradiation followed by bone marrow transplantation (BM-Tx) is a frequent therapeutic intervention causing pathology to the lung. Although alveolar epithelial type II (AE2) cells are essential for lung function and are damaged by irradiation, the long-term consequences of irradiation and BM-Tx are not well characterized. In addition, it is unknown whether surfactant protein D (SP-D) influences the response of AE2 cells to the injurious events. Therefore, wildtype (WT) and SP-D(-/-) mice were subjected to a myeloablative whole body irradiation dose of 8 Gy and subsequent BM-Tx and compared with age- and sex-matched untreated controls. AE2 cell changes were investigated quantitatively by design-based stereology. Compared with WT, untreated SP-D(-/-) mice showed a higher number of larger sized AE2 cells and a greater amount of surfactant-storing lamellar bodies. Irradiation and BM-Tx induced hyperplasia and hypertrophy in WT and SP-D(-/-) mice as well as the formation of giant lamellar bodies. The experimentally induced alterations were more severe in the SP-D(-/-) than in the WT mice, particularly with respect to the surfactant-storing lamellar bodies which were sometimes extremely enlarged in SP-D(-/-) mice. In conclusion, irradiation and BM-Tx have profound long-term effects on AE2 cells and their lamellar bodies. These data may explain some of the clinical pulmonary consequences of this procedure. The data should also be taken into account when BM-Tx is used as an experimental procedure to investigate the impact of bone marrow-derived cells for the phenotype of a specific genotype in the mouse

Measurements of the \gamma * p --> \Delta(1232) reaction at low Q2

We report new p$(\vec{e},e^\prime p)\pi^\circ$ measurements in the $\Delta^{+}(1232)$ resonance at the low momentum transfer region utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud dynamics are predicted to be dominant and appreciably changing in this region while the momentum transfer is sufficiently low to be able to test chiral effective calculations. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations with pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements

Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution

To determine nonspherical angular momentum amplitudes in hadrons at long ranges (low Q^2), data were taken for the p(\vec{e},e'p)\pi^0 reaction in the Delta region at Q^2=0.060 (GeV/c)^2 utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios at W=1232 MeV are: M_{1+}^{3/2} = (40.33 +/- 0.63_{stat+syst} +/- 0.61_{model}) (10^{-3}/m_{\pi^+}),Re(E_{1+}^{3/2}/M_{1+}^{3/2}) = (-2.28 +/- 0.29_{stat+syst} +/- 0.20_{model})%, and Re(S_{1+}^{3/2}/M_{1+}^{3/2}) = (-4.81 +/- 0.27_{stat+syst} +/- 0.26_{model})%. These disagree with predictions of constituent quark models but are in reasonable agreement with lattice calculations with non-linear (chiral) pion mass extrapolations, with chiral effective field theory, and with dynamical models with pion cloud effects. These results confirm the dominance, and general Q^2 variation, of the pionic contribution at large distances.Comment: 6 pages, 3 figures, 1 tabl

Determinants of antibody persistence across doses and continents after single-dose rVSV-ZEBOV vaccination for Ebola virus disease: an observational cohort study.

BACKGROUND: The recombinant vesicular stomatitis virus (rVSV) vaccine expressing the Zaire Ebola virus (ZEBOV) glycoprotein is efficacious in the weeks following single-dose injection, but duration of immunity is unknown. We aimed to assess antibody persistence at 1 and 2 years in volunteers who received single-dose rVSV-ZEBOV in three previous trials. METHODS: In this observational cohort study, we prospectively followed-up participants from the African and European phase 1 rVSV-ZEBOV trials, who were vaccinated once in 2014-15 with 300 000 (low dose) or 10-50 million (high dose) plaque-forming units (pfu) of rVSV-ZEBOV vaccine to assess ZEBOV glycoprotein (IgG) antibody persistence. The primary outcome was ZEBOV glycoprotein-specific IgG geometric mean concentrations (GMCs) measured yearly by ELISA compared with 1 month (ie, 28 days) after immunisation. We report GMCs up to 2 years (Geneva, Switzerland, including neutralising antibodies up to 6 months) and 1 year (Lambaréné, Gabon; Kilifi, Kenya) after vaccination and factors associated with higher antibody persistence beyond 6 months, according to multivariable analyses. Trials and the observational study were registered at ClinicalTrials.gov (Geneva: NCT02287480 and NCT02933931; Kilifi: NCT02296983) and the Pan-African Clinical Trials Registry (Lambaréné PACTR201411000919191). FINDINGS: Of 217 vaccinees from the original studies (102 from the Geneva study, 75 from the Lambaréné study, and 40 from the Kilifi study), 197 returned and provided samples at 1 year (95 from the Geneva study, 63 from the Lambaréné, and 39 from the Kilifi study) and 90 at 2 years (all from the Geneva study). In the Geneva group, 44 (100%) of 44 participants who had been given a high dose (ie, 10-50 million pfu) of vaccine and who were seropositive at day 28 remained seropositive at 2 years, whereas 33 (89%) of 37 who had been given the low dose (ie, 300 000 pfu) remained seropositive for 2 years (p=0·042). In participants who had received a high dose, ZEBOV glycoprotein IgG GMCs decreased significantly between their peak (at 1-3 months) and month 6 after vaccination in Geneva (p0·05). Neutralising antibodies seem to be less durable, with seropositivity dropping from 64-71% at 28 days to 27-31% at 6 months in participants from the Geneva study. INTERPRETATION: Antibody responses to single-dose rVSV-ZEBOV vaccination are sustained across dose ranges and settings, a key criterion in countries where booster vaccinations would be impractical. FUNDING: The Wellcome Trust and Innovative Medicines Initiative 2 Joint Undertaking