Desislava Todorova - Academia.edu (original) (raw)

Uploads

Papers by Desislava Todorova

Cellulose Chemistry and Technology

Cardiology

Introduction: In dilated cardiomyopathy (DCM) left ventricular (LV) strain and twist are signific... more Introduction: In dilated cardiomyopathy (DCM) left ventricular (LV) strain and twist are significantly decreased. However, the rate of attenuation has not been investigated well in patients with varying degrees of systolic dysfunction. Aim: The present study aimed to investigate the relationship between LV deformational and rotational mechanics and conventional and tissue Doppler imaging (TDI) parameters, and to search for a constellation of findings distinguishing patients with severe systolic dysfunction (SSD) in DCM. Methods: Fifty-two patients with heart failure NYHA class III–IV and ejection fraction (EF) ≤45% were prospectively enrolled (mean age 61.8 ± 13.4 years; 36 males, 69%). Severe systolic LV dysfunction was considered as EF <30%. Echocardiography with 2D-speckle tracking analysis was performed. Results: The relationships of global longitudinal strain (GLS) with EF, circumferential strain at mid-level (CSmid), and systolic medial mitral annulus velocity were strong (...

RUDN Journal of Agronomy and Animal Industries

The use of amperometric express method made it possible to measure quickly and evaluate content o... more The use of amperometric express method made it possible to measure quickly and evaluate content of waterand alcohol-soluble antioxidants in extracts from Amaranthus tricolor L. plants. Accumulation of low molecular weight antioxidants: ascorbic acid, beta-cyanine (amaranthine) and the total content of antioxidants in various organs of Valentina amaranth seedlings were studied. The maximum amount of low molecular weight antioxidants accumulates in leaves, compared with roots and stems of seedlings grown in open and protected ground. In open ground conditions, amaranth leaves and stems have 1.5-fold and 2-fold increased level of ascorbic acid than seedlings grown in protected ground. But the total content of water-soluble antioxidants in leaves and roots of seedlings is lower compared to seedlings of protected ground. Minimum amount of antioxidants was found in alcohol extracts of stems and roots in open ground, while the total content of antioxidants in stems and roots was 1.6 fold h...

Volga Region Pedagogical Search

Аннотация. Цель данного исследования-проанализировать полученную от учителей информацию о развити... more Аннотация. Цель данного исследования-проанализировать полученную от учителей информацию о развитии коммуникативной речевой компетенции у учащихся на ранних этапах, выяснить способность педагогов оценивать становление языковой компетентности учащихся. В качестве диагностического инструмента исследования была использована анкета. С опорой на полученные результаты можно заявить, что учителя должны быть в состоянии чётко оценивать способности учащихся уже на базовом уровне коммуникативной речевой компетенции детей, что в дальнейшем поможет точно определять содержание и уровень сложности образовательного контента для учащихся. Ключевые слова: коммуникативная речевая компетенция, болгарский язык и литература, базовый уровень образования.

Nature Communications

A thin elastic sheet lying on a soft substrate develops wrinkled patterns when subject to an exte... more A thin elastic sheet lying on a soft substrate develops wrinkled patterns when subject to an external forcing or as a result of geometric incompatibility. Thin sheet elasticity and substrate response equip such wrinkles with a global preferred wrinkle spacing length and with resistance to wrinkle curvature. These features are responsible for the liquid crystalline smectic-like behaviour of such systems at intermediate length scales. This insight allows better understanding of the wrinkling patterns seen in such systems, with which we explain pattern breaking into domains, the properties of domain walls and wrinkle undulation. We compare our predictions with numerical simulations and with experimental observations.

A gradient dynamics model based on an extended interface Hamiltonian is presented that is able to... more A gradient dynamics model based on an extended interface Hamiltonian is presented that is able to describe the dynamics of structuring processes in thin films of liquid mixtures, solutions and suspensions on solid substrates including coupled dewetting and decomposition. After discussing known limiting cases the model is employed to investigate the dewetting of thin films of liquid mixtures and suspensions under the influence of effective long-range van der Waals forces that depend on solute concentration. The occurring fluxes are discussed and it is shown that spinodal dewetting may be triggered through the coupling of film height and concentration fluctuations. Fully nonlinear calculations provide the time evolution and resulting steady film height and concentration profiles.

We discuss a thin film evolution equation for a wetting evaporating liquid on a smooth solid subs... more We discuss a thin film evolution equation for a wetting evaporating liquid on a smooth solid substrate. The model is valid for slowly evaporating small sessile droplets when thermal effects are insignificant, while wettability and capillarity play a major role. The model is first employed to study evaporating drops that are fed locally through the substrate as steady state solutions.

Central European Journal of Medicine, 2008

Thin Solid Films, 2012

The infra-red (IR) transmission spectra of SiO x (x ≤ 2) layers containing crystalline or amorpho... more The infra-red (IR) transmission spectra of SiO x (x ≤ 2) layers containing crystalline or amorphous Si nanoparticles deposited on p-Si substrates is simulated in the range 300-1500 cm − 1. To that purpose the average dielectric function of the nanocomposites is calculated by means of the Bruggeman effective medium approximation. The IR spectra of the system (film and substrate) are computed. The results are compared with experimental IR spectra measured on Si-SiO x nanocomposite layers with identical composition, fabricated by thermal evaporation of SiO in vacuum followed by thermal annealing at 700°C or 1030°C. A good correspondence between theory and experiment is found from where valuable information about important characteristics of the investigated nanocomposites is obtained, such as matrix density, homogeneity and composition of the layers.

Plant Growth Regulation, 2009

The effect of low doses (LD)-0.1 kJ m-2 d-1 and high doses (HD)-0.3 kJ m-2 d-1 of UV-C irradiatio... more The effect of low doses (LD)-0.1 kJ m-2 d-1 and high doses (HD)-0.3 kJ m-2 d-1 of UV-C irradiation on free, conjugated and bound spermine, spermidine and putrescine in leaves of young pea plants after 7 and 14 days of consecutive treatment was studied. Free polyamine (PA) fractions increased mainly in LD treated plants, while conjugated fractions decreased. Bound fractions accumulated mainly at the end of the experiment (after 14 days of UV-C irradiation). The results are interpreted in relation to the possible role of endogenous bound PAs in the prevention of membrane damage induced by UV-C irradiation. Stress markers (malondialdehyde and electrolyte leakage) increased after 7 days of UV-C treatment, and reached control values by the end of the experiment (mainly after HD treatment). Malondialdehyde concentration correlated negatively with UV-C-induced bound fraction and total PAs. The results support the conclusion that endogenous PAs lessen membrane damage in young pea plants provoked by UV-C irradiation.

Physical Review Letters, 2013

A thermodynamically consistent gradient dynamics model for the evolution of thin layers of liquid... more A thermodynamically consistent gradient dynamics model for the evolution of thin layers of liquid mixtures, solutions and suspensions on solid substrates is presented which is based on a film height-and mean concentration-dependent free energy functional. It is able to describe a large variety of structuring processes including coupled dewetting and decomposition processes. As an example, the model is employed to investigate the dewetting of thin films of liquid mixtures and suspensions under the influence of effective long-range van der Waals forces that depend on solute concentration. The occurring fluxes are discussed and it is shown that spinodal dewetting may be triggered through the coupling of film height and concentration fluctuations. Fully nonlinear calculations provide the time evolution and resulting steady film height and concentration profiles.

… European Journal of …, 2009

Post-communist Bulgaria has experienced the full impact of a socioeconomic disaster. Under prolon... more Post-communist Bulgaria has experienced the full impact of a socioeconomic disaster. Under prolonged and powerful stress the human body may exhaust its adaptive potential and a variety of pathophysiological symptoms may occur. The cardiovascular system is most vulnerable to stress. The aim of this study is to analyze the role of psychological factors correlating with Acute Myocardial Infarction (AMI) during the transition period in post-communist Bulgaria. A case-control epidemiological study was performed. 306 cases of acute myocardial infarction (AMI) and 210 controls were studied. Analysis of patients' records was made and a direct faceto-face interview was carried out. The study covers a 15-year transition period lasting from 1989 until 2005. The interview questions are based on W. Zung's standardized self-evaluation tests of anxiety and depression (Self Rating Depression Scale-SDS, 1965, SAS-Self Rating Anxiety Scale, 1976) and on a test of aggression, as a part of the Minnesota Multiphase personality inventory, adapted from A.A. Krilov and F. Korozi's FPI test. Average levels of anxiety and depression appear to be higher among patients suffering from coronary heart diseases than in control group members. Levels of aggression do not show a direct correlation with coronary heart disease. Both groups demonstrate symptoms of psychological disturbances caused, most probably, by the socioeconomic instability of the transition period. In conclusion, certain socioeconomic factors significantly increase the level of anxiety and depression in the respondents. The AMI patients are considerably more anxious and depressed than the controls. The results provide evidence that high levels of anxiety and depression may correlate to and be interpreted as a potential risk factor for coronary heart disease.

The Journal of Chemical Physics, 2013

We study equilibrium properties of polymer films and droplets on a solid substrate employing part... more We study equilibrium properties of polymer films and droplets on a solid substrate employing particle-based simulation techniques (Molecular Dynamics) and a continuum description. Parameter-passing techniques are explored that facilitate a detailed comparison of the two models. In particular, the liquid-vapor, solid-liquid and solid-vapor interface tensions, and the Derjaguin or disjoining pressure are determined by Molecular Dynamics simulations. This information is then introduced into continuum descriptions accounting for (i) the full curvature and (ii) a long-wave approximation of the curvature (thin film model). A comparison of the dependence of the contact angle on droplet size indicates that the theories agree well if the contact angles are defined in a compatible manner.