41 research outputs found

    Bosentan therapy for chronic thromboembolic pulmonary hypertension. A national open label study assessing the effect of Bosentan on haemodynamics, exercise capacity, quality of life, safety and tolerability in patients with chronic thromboembolic pulmonary hypertension (BOCTEPH-Study).

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    we performed an open-label national study to evaluate the effects of Bosentan on haemodynamics, exercise capacity, quality of life, safety and tolerability in patients with chronic thromboembolic pulmonary hypertension (CTEPH). fifteen patients with CTEPH not eligible or waiting for surgery were enrolled. The primary endpoint was the change in pulmonary vascular resistance (PVR). Secondary endpoints included quality of life (measured by the Minnesota living with heart failure questionnaire, MLHF), 6 minute walk distance (6MWD), World Health Organization (WHO) functional class, Borg dyspnoea scale, plasma endothelin, serum values of disease severity such as uric acid, N-terminal-pro brain natriuretic peptide (NTproBNP), C-reactive protein measured by a highly sensitive method (CRPs) and other serum and haemodynamic parameters. after six months of treatment with bosentan, the PVR decreased from 852 (319) to 657(249) dyn*s*m-5 (p = 0.02). Quality of life considerably improved from a mean total score of 48(14) to 35(17) (p = 0.003) with improvements in the physical (from 25(5) to 17(7)) and emotional (from 11(6) to 6(5)) subscores (p = 0.005 and 0.011), respectively. The 6MWD improved from 389(78) to 443(79) meters (p = 0.005). 4 patients (27%) improved and 11 patients (73%) maintained their WHO class with no deterioration during the six months of bosentan treatment (p = 0.02). Uric acid serum levels declined from 525(145) to 453(151) micromol/l (p = 0.006), NTproBNP and CRPs declined insignificantly. Endothelin serum levels increased from 4.3(1.5) to 5.9(2.2) pg/ml (p = 0.025). Patients tolerated the treatment well, and there were no severe adverse events or deaths. this open-label study suggests a beneficial effect of bosentan therapy not only on pulmonary haemodynamics, but also on quality of life and exercise capacity for patients with severe CTEPH

    A fully relativistic radial fall

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    Radial fall has historically played a momentous role. It is one of the most classical problems, the solutions of which represent the level of understanding of gravitation in a given epoch. A {\it gedankenexperiment} in a modern frame is given by a small body, like a compact star or a solar mass black hole, captured by a supermassive black hole. The mass of the small body itself and the emission of gravitational radiation cause the departure from the geodesic path due to the back-action, that is the self-force. For radial fall, as any other non-adiabatic motion, the instantaneous identity of the radiated energy and the loss of orbital energy cannot be imposed and provide the perturbed trajectory. In the first part of this letter, we present the effects due to the self-force computed on the geodesic trajectory in the background field. Compared to the latter trajectory, in the Regge-Wheeler, harmonic and all others smoothly related gauges, a far observer concludes that the self-force pushes inward (not outward) the falling body, with a strength proportional to the mass of the small body for a given large mass; further, the same observer notes an higher value of the maximal coordinate velocity, this value being reached earlier on during infall. In the second part of this letter, we implement a self-consistent approach for which the trajectory is iteratively corrected by the self-force, this time computed on osculating geodesics. Finally, we compare the motion driven by the self-force without and with self-consistent orbital evolution. Subtle differences are noticeable, even if self-force effects have hardly the time to accumulate in such a short orbit.Comment: To appear in Int. J. Geom. Meth. Mod. Phy

    On a class of invariant coframe operators with application to gravity

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    Let a differential 4D-manifold with a smooth coframe field be given. Consider the operators on it that are linear in the second order derivatives or quadratic in the first order derivatives of the coframe, both with coefficients that depend on the coframe variables. The paper exhibits the class of operators that are invariant under a general change of coordinates, and, also, invariant under the global SO(1,3)-transformation of the coframe. A general class of field equations is constructed. We display two subclasses in it. The subclass of field equations that are derivable from action principles by free variations and the subclass of field equations for which spherical-symmetric solutions, Minkowskian at infinity exist. Then, for the spherical-symmetric solutions, the resulting metric is computed. Invoking the Geodesic Postulate, we find all the equations that are experimentally (by the 3 classical tests) indistinguishable from Einstein field equations. This family includes, of course, also Einstein equations. Moreover, it is shown, explicitly, how to exhibit it. The basic tool employed in the paper is an invariant formulation reminiscent of Cartan's structural equations. The article sheds light on the possibilities and limitations of the coframe gravity. It may also serve as a general procedure to derive covariant field equations

    Fourth order gravity: equations, history, and applications to cosmology

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    The field equations following from a Lagrangian L(R) will be deduced and solved for special cases. If L is a non-linear function of the curvature scalar, then these equations are of fourth order in the metric. In the introduction we present the history of these equations beginning with the paper of H. Weyl from 1918, who first discussed them as alternative to Einstein's theory. In the third part, we give details about the cosmic no hair theorem, i.e., the details how within fourth order gravity with L= R + R^2 the inflationary phase of cosmic evolution turns out to be a transient attractor. Finally, the Bicknell theorem, i.e. the conformal relation from fourth order gravity to scalar-tensor theory, will be shortly presented.Comment: 51 pages, LaTeX, no figure, lecture for 42nd Karpacz Winter School 6.-11.2.06, references 99-109 and related comments are adde

    Comparison of apple tree water requirements in the Bydgoszcz (Poland) and Isparta (Turkey) regions

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    The aim of the present research was an attempt to compare apple tree water requirements in the vegetation period in the Bydgoszcz region (Poland) and in the Isparta region (Turkey). The paper refers to the 1984-2014 temperature and precipitation values in the Bydgoszcz and Isparta regions. To determine the reference evapotranspiration (ET0), the calculation model by Hargreaves modified by Droogers and Allen was applied. Potential evapotranspiration, identified with apple tree water requirements, was determined using the method of plant coefficients proposed by Doorenbos and Pruitt. In each of the seven months considered (April-October) higher apple tree water requirements occurred in the Isparta region. The highest apple tree water requirements were noted in July and for that month during the thirty-year period they were 167.3 mm and 286 mm, on average, in the Bydgoszcz and Isparta regions, respectively. Daily water requirements of apple trees in July were more than 9.2 mm in the Isparta region and 5.4 mm in the Bydgoszcz region. Apple tree water requirements throughout the vegetation period (April-October) were much higher (by 120 %) in the Isparta region than in the Bydgoszcz region. The highest precipitation deficits occurred in July and amounted to 95.5 mm and 269.1 mm for the Bydgoszcz and Isparta regions, respectively. The differences in the irrigation requirements for apple tree, next to water requirements differences, were affected by a different precipitation distribution in time in the regions com pared. In the Isparta region higher precipitation occurred at the beginning (April, May) and at the end (October) of the vegetation period, while in the Bydgoszcz region - just opposite - in summer months (June, July, August)

    Genetic polymorphisms of the serotonin transporter, but not the 2a receptor or nitric oxide synthetase, are associated with pulmonary hypertension in chronic obstructive pulmonary disease

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    Background: Pulmonary hypertension (PH) is prognosti- cally important in chronic obstructive pulmonary disease (COPD). Since PH only weakly correlates with hypoxemia, other factors must play a role. Objective: To investigate whether polymorphisms of the serotonin transporter (5HTT), serotonin-2a receptor (5HTR2a) and endothelial nitric oxide synthetase (eNOS) are related to PH in COPD. Methods: In 59 COPD patients who underwent right heart catheterization, 6-min walking distance, NYHA functional class, pulmonary function tests, blood gases and 5HTT, 5HTR2a and eNOS (4ab and T298C) polymorphisms were determined. Results: Forty-nine COPD patients in NYHA functional class III-IV were included. Ten were excluded due to comorbid causes of PH (mainly chronic thromboembolic). PH (mPAP ge25 mm Hg) was present in 55% and usually mild, but out of proportion (mPAP ge40 mm Hg) in 12%. Patients with PH had significantly higher frequencies of the 5HTT-L-allele (52%) compared to individuals without PH (36%), and LL homozygote patients had more severe PH. In patients with out-of-proportion PH, the L-allelic frequency was even 75%. We found no association of 5HTR2a and eNOS polymorphism with PH in COPD. Conclusions: In this COPD cohort we confirm that PH is frequent and usually mild, but out of proportion in a subgroup. We found a significant association of the L-allelic variant of 5HTT with PH overall and especially in out-of-proportion PH. These findings may point towards a role of the serotonin system in COPD-PH and warrant further studies

    Necessity of disinfecting water for crop irrigation

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    The purpose of that article was to show the significance of water as the source of plant pathogens, and need of it effective disinfection methods in modern agriculture and horticulture. The increase in the cost of agricultural water use for crop irrigation and the necessity of using the same water several times, as well as the changing climatic conditions, including prolonged shortage of atmospheric precipitation and often extreme temperatures during the summer, necessitate the selection of an effective, easy to apply and economical method of disinfecting recirculated water to eliminate or minimize the occurrence of the most serious plant pathogens inhabiting various water sources. Among them, microorganisms of the genera Phytophthora, Pythium and Fusarium, and the species Rhizoctonia solani, Verticillium dahliae and some pathogenic bacteria pose the most serious threat. Some of them can be found in rivers, streams, ponds and water reservoirs, others are soil-borne pathogens that cause root and stem base rot of many plant species. The available literature describes at least a dozen methods of water disinfection, among them slow filtration through sand or lava filters, chlorination and heating. The literature data indicates that the use of sand filters is the most effective, safe and cheapest method of water disinfection
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