Academic literature on the topic 'L410 NG'

The mechanism of vasoactive intestinal peptide (VIP)-induced pulmonary relaxation in tracheally perfused guinea pig lungs was defined with the use of inhibitors of nitric oxide synthase (NOS) and by direct measurement of nitric oxide (NO) equivalents recovered from lung perfusion fluid. Lungs treated with 200 microM NG-nitro-L-arginine were resistant to the relaxant effects of VIP in these lungs; the 50% inhibitory dose (ID50) for VIP was 32 nmol/kg (95% confidence interval, 16–79), which was approximately 100-fold greater than the ID50 of control lungs which was 0.39 nmol/kg, (0.16–0.79, P < 0.0001). This inhibitory effect could be overcome with excess L- but not D-arginine. In contrast, VIP-induced relaxation of isolated guinea pig trachea was not modified by inhibitors of NOS. To confirm that VIP infusion resulted in NO generation in whole lungs, we measured NO equivalents in lung effluent by two distinct technologies. We found that VIP injection caused a significant increase in NO equivalents from 0.11 +/- 0.04 microM to 0.78 +/- 0.15 microM (P < 0.05) and that this increase preceded VIP-induced pulmonary relaxation. Lungs pretreated with the putative guanylyl cyclase inhibitor methylene blue were less responsive to VIP [ID50 4.0 nmol/kg (1.5–10), P < 0.005 compared with control lungs], consistent with a physiologically significant guanosine 3',5'-cyclic monophosphate-dependent mechanism. Our data demonstrate that VIP has the capacity to relax whole lungs in part by stimulating the generation of NO.

By inference, muscarinic stimulation of glycoconjugate release from tracheal submucosal gland cells appears to be a transient, nonequilibrium process (J. M. Farley and T. M. Dwyer, Life Sci. 48: 59–67, 1991). To directly characterize the release kinetics of glycoconjugate, we developed an enzyme-linked lectin assay (ELLA) of much improved precision and resolution. To collect secreted products with an improved time resolution, freshly isolated swine tracheal submucosal gland cells were continuously superfused with medium 199 at 37 degrees, buffered with N-2-hydroxyethylpiperazine-N$#x0027-2-ethanesulfonic acid (HEPES) and CO2 or bicarbonate; fractions were collected every 15 s to 2 min. A 30-s pulse of 30 nM acetylcholine (ACh) increased the rate of glycoconjugate release by 10- to 25-fold for 2–3 min. The peak response averaged 14.2 +/- 9.0 ng protein.ml-1.min-1. 4 million cells-1 or 3.6 +/- 2.3 fg.cell-1.min-1 for 30 nM ACh and 16.2 +/- 3.0 ng protein.ml-1.min-1 for 100 nM ACh. There was no significant glycoconjugate release following a 30-s pulse of either 10 nM or 1 microM ACh. A second pulse after 7 min had no measurable effect on glycoconjugate release but a full response was obtained after 30 min. A continuous superfusion begun 1 min following the 30-s pulse resulted in a greater release of glycoconjugate than the pulse alone, but the response was not sustained, falling to twice basal levels within 5 min. We conclude that a brief muscarinic stimulation causes a triggered release of mucus glycoprotein followed by a relative refractory period.

Elevation in cell cAMP content can inhibit mitogenic signaling in cultured human airway smooth muscle (HASM) cells. We studied the effects of the type 3-selective phosphodiesterase inhibitor siguazodan, the type 4-selective phosphodiesterase inhibitor rolipram, and the nonselective inhibitor 3-isobutyl-1-methylxanthine (IBMX) on proliferation of cultured HASM cells. At concentrations selective for the type 3 phosphodiesterase isoform, siguazodan inhibited both [3H]thymidine incorporation (IC50 2 μM) and the increase in cell number (10 μM; 64% reduction) induced by platelet-derived growth factor-BB (20 ng/ml). These effects were mimicked by IBMX. At concentrations selective for type 4 phosphodiesterase inhibition, rolipram was without effect. A 20-min exposure to siguazodan and rolipram did not increase whole cell cAMP levels. However, in HASM cells transfected with a cAMP-responsive luciferase reporter (p6CRE/Luc), increases in cAMP-driven luciferase expression were seen with siguazodan (3.9-fold) and IBMX (16.5-fold). These data suggest that inhibition of the type 3 phosphodiesterase isoform present in airway smooth muscle results in inhibition of mitogenic signaling, possibly through an increase in cAMP-driven gene expression.

Nitric oxide (NO) is continuously produced and released in human airways, but the biological significance of this process is unknown. In this study, we have used Calu-3 cells to investigate the effects of NO on transepithelial anion secretion. An inhibitor of NO synthase, NG-nitro-l-arginine methyl ester, reduced short- circuit current ( Isc), whereas an NO donor, S-nitrosoglutathione (GSNO), increased Isc, with an EC50∼1.2 μM. The NO-activated current was inhibited by diphenylamine-2-carboxylate, clotrimazole, and charybdotoxin. Selective permeabilization of cell membranes indicated that NO activated both apical anion channels and basolateral potassium channels. An inhibitor of soluble guanylate cyclase, 1 H-[1,2,4]oxadiazolo[4,3- a]quinoxalin-1-one, prevented activation of Iscby NO but not by 8-bromo-cGMP, suggesting that NO acts via a cGMP-dependent pathway. Sequential treatment of cells with forskolin and GSNO or 1-ethyl-2-benzimidazolinone and GSNO showed additive effects of these chemicals on Isc. Interestingly, GSNO elevated intracellular Ca2+concentration ([Ca2+]i) but had no effect on Iscactivated by thapsigargin. These results show that NO activates transepithelial anion secretion via a cGMP-dependent pathway that involves cross talk between NO and [Ca2+]i.

Abstract. Throughout the year 2001, aerosol samples were collected continuously for 10 to 15 days at the French Antarctic Station Dumont d'Urville (DDU) (66°40' S, l40°0' E, 40 m above mean sea level). The nitrogen and oxygen isotopic ratios of particulate nitrate at DDU exhibit seasonal variations that are among the most extreme observed for nitrate on Earth. In association with concentration measurements, the isotope ratios delineate four distinct periods, broadly consistent with previous studies on Antarctic coastal areas. During austral autumn and early winter (March to mid-July), nitrate concentrations attain a minimum between 10 and 30 ng m−3 (referred to as Period 2). Two local maxima in August (55 ng m−3) and November/December (165 ng m−3) are used to assign Period 3 (mid-July to September) and Period 4 (October to December). Period 1 (January to March) is a transition period between the maximum concentration of Period 4 and the background concentration of Period 2. These seasonal changes are reflected in changes of the nitrogen and oxygen isotope ratios. During Period 2, which is characterized by background concentrations, the isotope ratios are in the range of previous measurements at mid-latitudes: δ18Ovsmow=(77.2±8.6)‰; Δ17O=(29.8±4.4)‰; δ15Nair=(−4.4±5.4)‰ (mean ± one standard deviation). Period 3 is accompanied by a significant increase of the oxygen isotope ratios and a small increase of the nitrogen isotope ratio to δ18Ovsmow=(98.8±13.9)‰; Δ17O=(38.8±4.7)‰ and δ15Nair=(4.3±8.20‰). Period 4 is characterized by a minimum 15N/14N ratio, only matched by one prior study of Antarctic aerosols, and oxygen isotope ratios similar to Period 2: δ18Ovsmow=(77.2±7.7)‰; Δ17O=(31.1±3.2)‰; δ15Nair=(−32.7±8.4)‰. Finally, during Period 1, isotope ratios reach minimum values for oxygen and intermediate values for nitrogen: δ18Ovsmow=63.2±2.5‰; Δ17O=24.0±1.1‰; δ15Nair=−17.9±4.0‰). Based on the measured isotopic composition, known atmospheric transport patterns and the current understanding of kinetics and isotope effects of relevant atmospheric chemical processes, we suggest that elevated tropospheric nitrate levels during Period 3 are most likely the result of nitrate sedimentation from polar stratospheric clouds (PSCs), whereas elevated nitrate levels during Period 4 are likely to result from snow re-emission of nitrogen oxide species. We are unable to attribute the source of the nitrate during periods 1 and 2 to local production or long-range transport, but note that the oxygen isotopic composition is in agreement with day and night time nitrate chemistry driven by the diurnal solar cycle. A precise quantification is difficult, due to our insufficient knowledge of isotope fractionation during the reactions leading to nitrate formation, among other reasons.

This master´s thesis deals with compiling a marketing plan for L 410 NG aircraft, manufactured by Aircraft Industries a.s.. The first part includes general theoretical knowledge, focusing on the process of formulating a plan by analyzing the external environment SLEPTE , Porter's five forces model, SWOT analysis and marketing mix 5P. In the second analytical part, the fundamental theory is applied to the company. On the basis of the results achieved, the individuals steps of a new marketing plan, including costs and time schedule are formulated in the final part of the thesis.

Master’s thesis deals with the damage tolerance evaluation of L410 NG aircraft lower wing integrally stiffened panel including crack growth and residual strength analyses and inspection program proposal. Presented DT evaluation has been done using FE model of the wing and AFGROW software.

This diploma thesis describes the design of composite structures rudder NG aircraft L410 based on the present Dural-weave construction. According to FAR 23 and circulars certification process is designed composite primary structure of the aircraft. It proposes the construction of a new rudder and selected materials design of a track composite materials. Program MSC Patran is this structure developed FEM model and using Nastran software Compost and the strength check.

The computational model design of a twin-engine, turbo-propeller, commuter aircraft and its two landing configuration analysis is the subject of the Master‘s thesis. The solution contents calibration part, creation of a computational mesh, global aerodynamics characteristics definition and detailed high lift devices load of L410 NG aircraft. The acquired results are compared to wind tunnel data. The comparison of accuracy and advantages of CFD is involved as well.

This master thesis deals with computational stress-strain analysis of the tailskid of airplane L410 NG with main focus firstly the check current design of the tailskid and then the design another design solution with the able to absorb as much as possible the deformation energy. Solution of this problem is performed using computational modeling utilizing numerical simulation of quasi-static and crash deformation load of the tailskid with using explicit Finite Element Method (FEM) in program ABAQUS v6.14. After the introduction with problem situation and tailskid assembly introductory part is devoted to the research study of various designs of the tailskid for different types of airplanes. There follows these theoretical general principles of thin-walled structures and buckling of them. Before the creating of the computational model itself, the explicit form of the Finite Element Method is better described. The conclusion of this thesis deals with the mutual comparison of the most advantageous design variants of the tailskid and the selection of the most suitable one of them for the airplane L410 NG.