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1 | INTRODUCTION Black women are disproportionately impacted by chronic illness and are significantly more likely to experience severe morbidity and mortality as a consequence of pregnancy and childbirth. (1,2) [...]

Abstract: The article analyzes the impact of the sanctions policies of Western countries on the agri-food sector. It is noted that in difficult geopolitical and macroeconomic conditions, many problems that existed in the agri-food sector even before the increase in sanctions pressure on the Russian economy were exposed and intensified. With a high level of self-sufficiency in food products, the industry has maintained a high level of import dependence of agricultural production, primarily for seeds and breeding material, as well as for many other components of agricultural production. Adaptation strategies of the agri-food sector to new conditions are aimed at accelerating import substitution and increasing domestic production and replacing the importer from Western countries with a supplier of similar products from friendly countries. The increased attention to import substitution and the growth of investment attractiveness of the industry are shown. Key problem areas of the industry have been identified, including rising production costs, decreasing profitability and, as a consequence, decreasing demand for domestic agricultural machinery, and exacerbating the problem of personnel shortages in agriculture. The role of exports as a driver of production growth in a few agricultural sectors is noted in the absence of prerequisites for the growth of domestic consumption, which is hampered by a decrease in the purchasing power of per capita monetary income of the population and the lack of population growth. A decrease in profitability in agriculture against the backdrop of a significant increase in costs leads to a reduction in the purchase of domestic agricultural machinery products by agricultural producers and hits producers in related industries up and down the value chain. It is concluded that the sources of growth in agricultural production in the short and medium term will be import substitution in the field of breeding, ensuring an increase in the profitability of agricultural production, eliminating the shortage of labor resources in agriculture, increasing the investment attractiveness of the agri-food sector for new investors, developing exports.

In the over 100 years since the recognition of pulmonary hypertension (PH), immense progress and significant achievements have been made with regard to understanding the pathophysiology of the disease and its treatment. These advances have been mostly in idiopathic pulmonary arterial hypertension (IPAH), which was classified as Group 1 Pulmonary Hypertension (PH) at the Second World Symposia on PH in 1998. However, the pathobiology of PH due to chronic lung disease, classified as Group 3 PH, remains poorly understood and its treatments thus remain limited. We review the history of the classification of the five groups of PH and aim to provide a state-of-the-art review of the understanding of the pathogenesis of Group 1 PH and Group 3 PH including insights gained from novel high-throughput omics technologies that have revealed heterogeneities within these categories as well as similarities between them. Leveraging the substantial gains made in understanding the genomics, epigenomics, proteomics, and metabolomics of PAH to understand the full spectrum of the complex, heterogeneous disease of PH is needed. Multimodal omics data as well as supervised and unbiased machine learning approaches after careful consideration of the powerful advantages as well as of the limitations and pitfalls of these technologies could lead to earlier diagnosis, more precise risk stratification, better predictions of disease response, new sub-phenotype groupings within types of PH, and identification of shared pathways between PAH and other types of PH that could lead to new treatment targets. © 2023 American Physiological Society. Compr Physiol13:4295-4319, 2023. New methodologies have demonstrated significant heterogeneity in the types of pulmonary vascular lesions observed in pulmonary arterial hypertension (PAH). They have also revealed both pathobiologic similarities as well as differences between PAH and other diseases in which pulmonary hypertension (PH) is observed, such as idiopathic pulmonary fibrosis (IPF).Patients with pulmonary hypertension secondary to lung disease (Group 3 PH) have equally poor if not worse mortality compared to those with pulmonary arterial hypertension (Group 1 PH) despite having lower pulmonary arterial pressure and right ventricular dysfunction, highlighting the urgent need to understand its pathobiologic underpinnings, which could lead to identification of new therapeutic options.At present, it remains unclear whether treatment of other groups of PH with the pulmonary vasodilator therapies used in Group 1 PH is appropriate or potentially harmful.While there are likely pathologic differences between Group 1 and Group 3 PH, application of rigorous techniques including lung stereology (i.e. quantification of three-dimensional anatomic abnormalities) and precise localization of vascular lesions (for example in relationship to areas of fibrosis) will help define the significance of these differences.Multimodal omics data as well as supervised and unbiased machine learning could lead to earlier diagnosis, more precise risk stratification, better predictions of disease response, new sub-phenotype groupings within types of PH, and identification of shared pathways between PAH and other types of PH that could lead to new treatment targets.

In this work, the structure of aluminum alloy modified with shungite carbon additives after high-pressure thermal treatment is studied. Introducing shungite carbon into an aluminum matrix is shown to inhibit aluminum grain growth and to increase the microhardness of the composite.

Our objective was to determine whether left ventricular (LV) vorticity (ω), the local spinning motion of a fluid element, correlated with markers of ventricular interdependency in pulmonary hypertension (PH). Maladaptive ventricular interdependency is associated with interventricular septal shift, impaired LV performance, and poor outcomes in PH patients, yet the pathophysiologic mechanisms underlying fluid-structure interactions in ventricular interdependency are incompletely understood. Because conformational changes in chamber geometry affect blood flow formations and dynamics, LV ωmay be a marker of LV-RV (right ventricular) interactions in PH. Echocardiography was performed for 13 PH patients and 10 controls for assessment of interdependency markers, including eccentricity index (EI), and biventricular diastolic dysfunction, including mitral valve (MV) and tricuspid valve (TV) early and late velocities (Eand A, respectively) as well as MV septal and lateral early tissue Doppler velocities (e′). Same-day 4-dimensional cardiac magnetic resonance was performed for LV E (early)-wave ωmeasurement. LV E-wave ωwas significantly decreased in PH patients (P =0.008) and correlated with diastolic EI (Rho = −0.53, P =0.009) as well as with markers of LV diastolic dysfunction, including MV E(Rho = 0.53, P =0.011), E/A(Rho = 0.56, P =0.007), septal e′ (Rho = 0.63, P =0.001), and lateral e′ (Rho = 0.57, P =0.007). Furthermore, LV E-wave ωwas associated with indices of RV diastolic dysfunction, including TV e′ (Rho = 0.52, P =0.012) and TV E/A(Rho = 0.53, P =0.009). LV E-wave ωis decreased in PH and correlated with multiple echocardiographic markers of ventricular interdependency. LV ωmay be a novel marker for fluid-tissue biomechanical interactions in LV-RV interdependency.

Pulmonary hypertension (PH) is associated with proximal pulmonary arterial remodeling characterized by increased vessel diameter, wall thickening, and stiffness. In vivo assessment of wall shear stress (WSS) may provide insights into the relationships between pulmonary hemodynamics and vascular remodeling. We investigated the relationship between main pulmonary artery (MPA) WSS and pulmonary hemodynamics as well as markers of stiffness. As part of a prospective study, 17 PH patients and 5 controls underwent same-day four-dimensional flow cardiac magnetic resonance imaging (4-D CMR) and right heart catheterization. Streamwise velocity profiles were generated in the cross-sectional MPA in 45° increments from velocity vector fields determined by 4-D CMR. WSS was calculated as the product of hematocrit-dependent viscosity and shear rate generated from the spatial gradient of the velocity profiles. In-plane average MPA WSS was significantly decreased in the PH cohort compared with that in controls (0.18 ± 0.07 vs. 0.32 ± 0.08 N/m2; P =0.01). In-plane MPA WSS showed strong inverse correlations with multiple hemodynamic indices, including pulmonary resistance (ρ = –0.74, P <0.001), mean pulmonary pressure (ρ = –0.64, P =0.006), and elastance (ρ = –0.70, P <0.001). In addition, MPA WSS had significant associations with markers of stiffness, including capacitance (ρ =0.67, P <0.001), distensibility (ρ =0.52, P =0.013), and elastic modulus (ρ = –0.54, P =0.01). In conclusion, MPA WSS is decreased in PH and is significantly associated with invasive hemodynamic indices and markers of stiffness. 4-D CMR-based assessment of WSS may represent a novel methodology to study blood-vessel wall interactions in PH.

Pulmonary arterial hypertension (PAH) is a progressive disease that puts excessive mechanical loads on the ventricle due to a gradual increase in pulmonary vascular impedance. We hypothesize that the increase in right ventricular (RV) afterload is reflected in the concentration of circulating biochemical markers of ventricular strain and stress (B-type natriuretic peptide [BNP] and N-terminal prohormone BNP [NT-proBNP]). We retrospectively analyzed right heart catheterization (RHC) and serum biochemical analysis data () for a pediatric PAH cohort with no sign of left ventricular dysfunction. Using RHC data, we computed an estimate of pulmonary vascular resistance (PVR), compliance, and ventricular-vascular coupling. We also compared how the early onset of interventricular decoupling (characterized as septal flattening) impacts serum NT-proBNP concentrations. Our data revealed correlated NT-proBNP expression with both the resistive and reactive components of RV afterload, an estimate of ventricular-vascular coupling, and a significant increase in biomarker expression in patients with a flattened interventricular septum. Furthermore, the strong correlation between PVR and NT-proBNP appears to break down under flat septum morphology. Over 80% of resistive RV afterload variance is reflected in serum NT-proBNP concentration in pediatric patients with PAH with no sign of left ventricular dysfunction. Reactive afterload appears to contribute to myocardial NT-proBNP release at advanced stages of PAH. Therefore, in mild-to-moderate PAH, resistive afterload is likely the greatest contributor to RV wall stress. These findings could also be used to estimate invasive RHC measurements from serum biochemical analysis, but more work is needed to improve correlations and overcome the issue of interventricular decoupling.

Pulmonary hypertension (PH) is a devastating disease affecting approximately 15–50 people per million, with a higher incidence in women. PH mortality is mostly attributed to right ventricle (RV) failure, which results from RV hypotrophy due to an overburdened hydraulic workload. The objective of this study is to correlate wall shear stress (WSS) with hemodynamic metrics that are generally accepted as clinical indicators of RV workload and are well correlated with disease outcome. Retrospective right heart catheterization data for 20 PH patients were analyzed to derive pulmonary vascular resistance (PVR), arterial compliance (C), and an index of wave reflections (Γ). Patient-specific contrast-enhanced computed tomography chest images were used to reconstruct the individual pulmonary arterial trees up to the seventh generation. Computational fluid dynamics analyses simulating blood flow at peak systole were conducted for each vascular model to calculate WSS distributions on the endothelial surface of the pulmonary arteries. WSS was found to be decreased proportionally with elevated PVR and reduced C. Spatially averaged WSS (SAWSS) was positively correlated with PVR (R2= 0.66), C(R2= 0.73), and Γ (R2= 0.5) and also showed promising preliminary correlations with RV geometric characteristics. Evaluating WSS at random cross sections in the proximal vasculature (main, right, and left pulmonary arteries), the type of data that can be acquired from phase-contrast magnetic resonance imaging, did not reveal the same correlations. In conclusion, we found that WSS has the potential to be a viable and clinically useful noninvasive metric of PH disease progression and RV health. Future work should be focused on evaluating whether SAWSS has prognostic value in the management of PH and whether it can be used as a rapid reactivity assessment tool, which would aid in selection of appropriate therapies.

Introduction:Right ventricular (RV) failure is the leading cause of death in patients with pulmonary arterial hypertension (PAH). Capillary rarefaction has been proposed as the hallmark of RV failure, yet our understanding of the capillary architecture is limited by 2D image analysis. Three-dimensional (3D) confocal deep tissue imaging offers the unparalleled opportunity to characterize the architectural microvascular changes in relationship to cardiomyocytes in pressure-overloaded RV failure.Methods and Results:250 μm heart tissue slices from mice with RV failure, 7-weeks after Pulmonary Artery Banding (PAB) were harvested and the microvascular network was assessed for density, segment length, diameter, orientation, as well as microvasculature-cardiomyocyte contact area in regions with and without interstitial fibrosis using confocal 3D imaging. Human heart tissue from end-stage PAH patients was compared to controls with normal RV function. In PAB mice, 3D imaging of the RV free wall revealed tortuous, shorter, thicker and higher-branched microvascular segments as well as development of fibrosis compared to Sham animals (Fig A). When corrected for fibrosis, the microvascular density was preserved even in advanced stages of RV failure. Physical contact between the microvasculature and cardiomyocytes was preserved in areas without fibrosis, yet significantly impaired in areas with interstitial fibrosis (Fig B), accompanied by an overexpression of β-myosin heavy chain suggesting local ischemia (Fig C). 3D imaging of human RV tissue of end-stage PAH patients revealed architectural microvascular remodeling that varied depending on etiologies and length of disease yet showed preserved microvascular density. (Fig. D).Conclusions:3D deep tissue imaging revealed compensatory changes of the microvascular network to maintain a stable cardiomyocyte coverage in pressure-overloaded RV failure, which was impaired in areas of interstitial fibrosis.

The canonical quantum theory of gravity-quantum geometrodynamics (QG)-is applied to the homogeneous Bianchi type IX cosmological model. As a result, a framework for the quantum theory of homogeneous cosmologies is developed. We show that the theory is internally consistent and prove that it possesses the correct classical limit (the theory of general relativity). To emphasize the special role that the constraints play in this new theory, we compare it to the traditional ADM square-root and Wheeler-DeWitt quantization schemes. We show that, unlike traditional approaches, QG leads to a well-defined Schrödinger equation for the wavefunction of the universe that is inherently coupled to the expectation value of the constraint equations. This coupling to the constraints is responsible for the appearance of a coherent spacetime picture. Thus, the physical meaning of the constraints of the theory is quite different from Dirac's interpretation. In light of this distinctive feature of the theory, we re-address the question of the dark energy effects in the Bianchi IX cosmological model for highly non-classical quantum states. We show that, at least for this model, for any choice of the initial wavefunction, quantum corrections will not produce accelerated expansion of the universe.

The search for an understanding of an energy source great enough to explain the gamma-ray burst (GRB) phenomenon has attracted much attention from the astrophysical community since its discovery. In this paper we extend the work of Asano and Fukuyama, and Salmonson and Wilson and analyze the off-axis contributions to the energy-momentum deposition rate (MDR) from the n-img1.gif collisions above a rotating black hole/thin accretion disk system. Our calculations are performed by imaging the accretion disk at a specified observer using the full geodesic equations and calculating the cumulative MDR from the scattering of all pairs of neutrinos and antineutrinos arriving at the observer. Our results shed light on the beaming efficiency of GRB models of this kind. Although we confirm Asano and Fukuyama's conjecture as to the constancy of the beaming for small angles away from the axis, we find that the dominant contribution to the MDR comes from near the surface of the disk with a tilt of approximately p/4 in the direction of the disk's rotation. We find that the MDR at large radii is directed outward in a conic section centered around the symmetry axis and is larger by a factor of 10-20 than the on-axis values. By including this off-axis disk source, we find a linear dependence of the MDR on the black hole angular momentum.

We analyze the Schild's ladder parallel transport procedure for an arbitraryconnection. We demonstrate that the procedure, while it can be performed forany connection, in fact is only capable of detecting the symmetric part of thisconnection. In geometries with a symmetric connection it fulfills its goal toexpress connection and parallel transport of any vector in terms of geodesics ofsuch geometries.

Introduction:Right ventricular (RV) function determines the prognosis of pulmonary hypertension. Capillary rarefaction using 2D imaging has been proposed as the hallmark of RV failure, although this paradigm is controversially discussed. By applying 3D deep-tissue imaging, we characterized the adaptive and maladaptive response of the capillaries in the pressure-overloaded RV in hypertrophy and failure.Methods and Results:Mice subjected to pulmonary artery banding (PAB) were harvested after 3 weeks (w) (compensated RV hypertrophy) and 7w post-surgery (decompensated RV failure). Hearts were sectioned into 250 μm and capillaries were stained with isolectin B4. Samples were imaged with confocal microscopy and reconstructed into 3D using Imaris imaging software (Fig. A, n=4). In the RV free wall, mean capillary length decreased, and branching, tortuosity, mean and total capillary diameter increased 3w post-PAB. Mean and total diameter, and total length decreased at 7w resulting in a reduced capillary volume normalized to heart volume at 7w vs 3w, but not significantly reduced vs baseline suggesting that this is not the mechanism of RV failure (Fig. B). However, most strikingly we uncovered by sparsely labeling cardiomyocytes that the capillary-cardiomyocyte contact surface was maintained at w3, yet significantly decreased in areas of interstitial fibrosis in the decompensated RV at 7w compared to baseline and 3w (Fig. C, D).Conclusions:3D deep-tissue imaging uncovered the remarkable adaptive response of the RV microvasculature in the pressure-overloaded RV to maintain an adequate capillary-cardiomyocyte contact by increasing capillary branching, length and diameter. These mechanisms failed in the decompensating RV when interstitial fibrosis impaired the capillary-cardiomyocyte interaction. Our method offers the unprecedented opportunity to study microvascular adaption in the pressure overloaded RV and is readily transferable to human tissue.

Introduction:The left ventricle (LV) is known to transfer kinetic mechanical energy to the right ventricle (RV) during systole. Normally, the RV relies on this mechanical assistance for up to 70% of its pressure generation. However, this biventricular relationship and its effect on RV function has not been explored in the progression in the pressure overloaded RV. In this study, we developed a longitudinal mouse model of pulmonary arterial (PA)-banding concomitant with transverse aortic constriction (TAC) to initiate an adaptive LV remodeling response. We hypothesized that adaptive LV remodeling would improve RV systolic function in an RV pressure overloaded setting.Methods:Surgical PAB was performed on mice to induce RV pressure overload and myocardial remodeling. Mild surgical TAC was performed on these mice 2-weeks (w) post-PAB. Steady-state free precession (SSFP) cardiac magnetic resonance (CMR) imaging (SSFP-CMR) was performed at 1w post-PAB, 1 w post-TAC (PAB-TAC) and 4 w and 7 w post-surgery (n=7). As controls we used Sham (n=5), TAC-only (n=4, TAC) as well as PAB-only (n=4, PAB) mice at 1, 4, and 7 w after surgery. These images were analyzed using feature-tracking (FT) software to compute measurements of ventricular volumes.Results:RV ejection fraction (RVEF) was reduced in PAB mice compared to Sham at 1w (p=0.02, 0.38±0.06 versus 0.52±0.08, respectively). After TAC, PAB-TAC mice showed an increase in RVEF compared to PAB-only mice at 4 w (p=0.03, 0.49±0.04 versus 0.39±0.08, respectively), and at 7 w (p=0.001, 0.50±0.06 versus 0.37±0.1, respectively). Similarly, tricuspid annular plane systolic excursion (TAPSE) showed a decrease in PAB mice compared to sham (p=0.002, 0.85±0.15mm versus 1.73±0.33mm, respectively) and an increase after TAC at 2 w (p=0.001, 1.55±0.29mm versus 0.85±0.15mm, respectively), 4 w (p=0.002, 1.75±0.32mm versus 0.93±0.21mm, respectively), and at 7 w post-surgery (p=0.001, 1.70±0.33mm versus 0.91±0.14mm, respectively).Conclusions:Even though LV-to-RV mechanical energy transfer is well established in normotensive animals, our data supports a mechanistic link between RV systolic function and LV pressure in remodeled and pressure-overloaded RVs.

Editor's Note: This article has been retracted. Please see the retraction notice for more detail: https://www.nature.com/articles/s41443-020-0321-x

We discuss quantum insights due to the null-strut formalism. These insights deal primarily with two topics: the formalism of a theory of canonical simplicial quantum gravity based on the geometrodynamic duality of null-strut calculus, and the natural implementation of spinors and spin networks in null-strut calculus.

We establish a correspondence between the recently proposedP(4) affine and the standard superhamiltonian descriptions of the electrodynamics of classical charged particles. TheP(4) theory uses a generalized affine connection on the affine frame bundleA(M) over spacetime, and an affine connection is induced on phase space thought of as the vector bundleT*M. On the phase space manifoldT*M this affine structure defines a covariant canonical symplectic form, which, when coupled with the canonical free-particle superhamiltonian, reproduces the Lorentz force law for classical charged particles. Conversely, one may “split” the noncanonical symplectic form onT*M to define an affine connection onA(M) and thus return to theP(4) theory from symplectic geometry. The correspondence also allows a geometrization of superhamiltonian dynamics. Roughly speaking, the symplectic form onT*M is geometrized as anR4-affine connection onA(M), and the superhamiltonian is geometrized as an affine difference function on the local momentum-energy tangent affine spaces.

Abstract: The boundary of a boundary principle in field theories is described. The difference in treatment of the principle in electrodynamics and general relativity is pointed out and reformulated in terms of underlying mathematical structure of the theories. The problem of unifying the treatment is formulated and solved. The role of E. Cartan's concept of the moment of rotation associated with the curvature of a Levi-Civita connection on a frame bundle is shown to be crucial for the unification. The analysis of the boundary of a boundary principle in Kaluza-Klein theory is performed and the recipe for a unified treatment of the principle in electrodynamics and general relativity is shown to follow from the analysis. It is pointed out that the unification cand be extended to Yang-Mills fields easily.

An ability to analyze the geometrodynamic degrees of freedom and initial-data formulation is central to the canonical quantization of gravity. In the metric theory of gravity York provided the most powerful technique to analyze the dynamic degrees of freedom and to solve the initial-data problem. In this paper we extend York's analysis to tetrad gravity. Such an extension is necessary for the quantization of gravity when coupled to a half-integer-spin field. We present a comparative analysis of the geometric information carried by (1) a 3-metric of an initial hypersurface and (2) the spacelike triad of a time-gauged tetrad. We apply the tetrad initial-data formulation to Ashtekar's connection variables, and provide a comparison with other alternative choices of canonical tetrad variables.

We formulate the boundary of a boundary principle, review its applications in electrodynamics, Yang-Mills theory, and general relativity and translate its basic ideas into geometric language. In each of these three theories the density of the source lets itself be constructed-we discover-out of the curvature associated with the field as a Cartan-like moment of this curvature.

Pulmonary hypertension may arise as a complication of chronic lung disease typically associated with tissue hypoxia, as well as infectious agents or injury eliciting a type 2 immune response. The onset of pulmonary hypertension in this setting (classified as Group 3) often complicates treatment and worsens prognosis of chronic lung disease. Chronic lung diseases such as chronic obstructive lung disease (COPD), emphysema, and interstitial lung fibrosis impair airflow and alter lung elastance in addition to affecting pulmonary vascular hemodynamics that may culminate in right ventricle dysfunction. To date, functional endpoints in murine models of chronic lung disease have typically been limited to separately measuring airway and lung parenchyma physiology. These approaches may be lengthy and require a large number of animals per experiment. Here, we provide a detailed protocol for combined assessment of airway physiology with cardiovascular hemodynamics in mice. Ultimately, a comprehensive overview of pulmonary function in murine models of injury and disease will facilitate the integration of studies of the airway and vascular biology necessary to understand underlying pathophysiology of Group 3 pulmonary hypertension.

We randomly assigned 39 patients with stroke and homonymous hemianopia or unilateral visual neglect to treatment with 15-diopter plastic press-on Fresnel prisms (n 18) or to serve as controls (n 21). Baseline evaluations of visual perception and activities-of-daily-living (ADL) function were similar for both groups. After 4 weeks, the prism-treated group performed significantly better than controls on the following: (1) Motor Free Visual Perception Test; (2) Line Bisection Task; (3) Line Cancellation Task; (4) Harrington Flocks Visual Field Screener; and (5) Tangent Screen Examination. There was no significant difference in Barthel ADL assessment at 4 weeks. Thus, treatment with 15-diopter Fresnel prisms improves visual perception test scores but not ADL function in stroke patients with homonymous hemianopia or unilateral visual neglect.

Conclusions 1.The existing methods of quenching fix the residual austenite in the structure of ShKh15 and KhVG steels.2.The aging of tempered specimens at 130–140° for 24–48 hours does not cause any further reduction in the residual austenite and should not be recommended.3.The aging of parts made of ShKh15 and KhVG steels at 160° reduces the amount of residual austenite by 1.5–2.5%, the most intensive decomposition occurring in the case of KhVG steel within the first 2 to 4 hours, and in the case of ShKh15 steel within the first 5–7 hours. Further soaking is technologically inadvisable.4.Tempering at temperatures not above 160° as well as prolonged aging at 130–140° do not harden the residual austenite. Stable dimensions of parts made of ShKh15 and KhVG steels are only obtained after cold working (-30–70°) if the latter is applied immediately after quenching.5.We can recommend the following heat treatment regime for parts made of ShKh15 or KhVG steels for fuel equipment:a)quenching from 830–840° in alkali or oil;b)cold working at -30–-70°;c)tempering at 160° for 4 or 5 hours, cooling in air;d)aging after machining for 2 or 3 hours at 160°.

The right ventricle and left ventricle are physically coupled through the interventricular septum. Therefore, changes in the geometry and mechanics of one ventricle can directly affect the function of the other. In treatment of pediatric pulmonary arterial hypertension, the left ventricle is often overlooked, with clinical focus primarily on improving right ventricular function. Pediatric pulmonary arterial hypertension represents a disease distinct from adult pulmonary arterial hypertension based on etiology and survival rates. We aimed to assess left ventricular torsion rate in pediatric pulmonary arterial hypertension and its role in right ventricular dysfunction. Cardiac magnetic resonance images with tissue tagging were prospectively acquired for 18 pediatric pulmonary arterial hypertension (WHO class I) patients and 17 control subjects with no known cardiopulmonary disease. The pulmonary arterial hypertension cohort underwent cardiac magnetic resonance within 48 hours of clinically indicated right heart catheterization. Using right heart catheterization data, we computed single beat estimation of right ventricular end-systolic elastance (as a measure of right ventricular contractility) and ventricular vascular coupling ratio (end-systolic elastance/arterial afterload). Left ventricular torsion rate was quantified from harmonic phase analysis of tagged cardiac magnetic resonance images. Ventricular and pulmonary pressures and pulmonary vascular resistance were derived from right heart catheterization data. Right ventricular ejection fraction and interventricular septum curvature were derived from cardiac magnetic resonance. Left ventricular torsion rate was significantly reduced in pulmonary arterial hypertension patients compared to control subjects (1.40 ± 0.61° vs. 3.02 ± 1.47°, P< 0.001). A decrease in left ventricular torsion rate was significantly correlated with a decrease in right ventricular contractility (end-systolic elastance) (r= 0.61, P= 0.007), and an increase in right ventricular systolic pressure in pulmonary arterial hypertension kids (r= –0.54, P= 0.021). In both pulmonary arterial hypertension and control subjects, left ventricular torsion rate correlated with right ventricular ejection fraction (controls r= 0.45, P= 0.034) (pulmonary arterial hypertension r= 0.57, P= 0.032). In the pulmonary arterial hypertension group, interventricular septum curvature demonstrated a strong direct relationship with right ventricular systolic pressure (r= 0.7, P= 0.001) and inversely with left ventricular torsion rate (r= –0.57, P= 0.013). Left ventricular torsion rate showed a direct relationship with ventricular vascular coupling ratio (r= 0.54, P= 0.021), and an inverse relationship with mean pulmonary arterial pressure (r= –0.60, P= 0.008), and pulmonary vascular resistance (r= –0.47, P= 0.049). We conclude that in pediatric pulmonary arterial hypertension, reduced right ventricular contractility is associated with decreased left ventricular torsion rate.

The capabilities of geometrically accurate computational 3D models construction with the use of programming are presented. The construction of models of an architectural arch and a glo-boid worm gear is considered as an example. The models are designed in the AutoCAD pack-age. Three programs of construction are given. The first program is for designing a multi-section architectural arch. The control of the arch's geometry by impacting its main parameters is shown. The second program is for designing and studying the working surface of a globoid gear's worm. The article shows how to make the animation for this surface's formation. The third program is for formation of a worm gear cavity surface. The cavity formation dynamics is studied. The programs are written in the AutoLisp programming language. The program texts are provided.

The paper gives a geometric proof of the theorem which states that in case of the plane section of a second-order surface of rotation (quadrics of rotation, QR), such conics as an ellipse, a hyperbola or a parabola (types of conic sections) are formed. The theorem supplements the well-known Dandelin's theorem which gives the geometric proof only for a circular cone and applies the proof to all QR, namely an ellipsoid, a hyperboloid, a paraboloid and a cylinder. That's why the considered theorem is known as the generalized Dandelin's theorem (GDT). The GDT proof is based on a relatively unknown generalized directrix definition (GDD) of conics. The work outlines the GDD proof for all types of conics as their necessary and sufficient condition. Based on the GDD, the author proves the GDT for all QR in case of a random position of the cutting plane. The graphical stereometric structures necessary for the proof are given. The implementation of the structures by 3d computer methods is considered. The article shows the examples of the builds made in the AutoCAD package. The theorem is intended for the training course of theoretical training of elite student groups of architectural and construction specialties.

The use of 3D modeling when constructing and analyzing perspective projections and shadows is considered. The creation of photorealistic image is shown. The perspective of the construction project and characterization of its image are given as an example. The authors consider the construction of a dynamic block as a means of graphical information storage and automation of geometric constructions. The example of the dynamic block construction at creating a truss node is demonstrated. The constructions are considered as applied to the Auto-CAD software. The paper is aimed at improving the graphic methods of architectural design and improving the educational process when training the Bachelor's degree students majoring in construction.

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