120 results match your criteria: "Technical University of Sofia[Affiliation]"

A distinction between indolent and aggressive disease is a major challenge in diagnostics of prostate cancer. As genetic heterogeneity and complexity may influence clinical outcome, we have initiated studies on single tumor cell genomics. In this study, we demonstrate that sparse DNA sequencing of single-cell nuclei from prostate core biopsies is a rich source of quantitative parameters for evaluating neoplastic growth and aggressiveness.

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In this paper, we propose a fractional-order neural network system with time-varying delays and reaction-diffusion terms. We first develop a new Mittag-Leffler synchronization strategy for the controlled nodes via impulsive controllers. Using the fractional Lyapunov method sufficient conditions are given.

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Background: Data on coagulation changes in paroxysmal atrial fibrillation (PAF) are scarce. The aim of this study was to examine plasma antithrombin (AT) levels and activity as well as thrombin-antithrombin (TAT) complex levels in the early hours of the clinical manifestation of PAF.

Methods: Fifty-one patients (26 men and 25 women; mean age 59.

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Background: A number of data have been accumulated on inflammation in persistent and permanent atrial fibrillation (AF). Our aim was to study the process in paroxysmal AF (PAF) by measuring plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) and fibrinogen in dynamics.

Methods: The markers were investigated in 51 patients (26 males and 25 females; 59.

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The thin films of CdS(1-x)Se(x) were successfully deposited over glass substrates by chemical bath deposition technique. Cadmium acetate, thiourea and sodium selenosulfate were used as source materials for Cd(2+), S(2-) and Se(2-) ions, while 2-mercaptoethanol was used as capping agent. The various deposition conditions such as precursor concentration, deposition temperature, pH and deposition time were optimized for the deposition of CdS(1-x)Se(x) thin films of good quality and the films were annealed at 200° and 300 °C.

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The aim of this paper is to identify the common neural signatures based on which the positive and negative valence of human emotions across multiple subjects can be reliably discriminated. The brain activity is observed via Event Related Potentials (ERPs). ERPs are transient components in the Electroencephalography (EEG) generated in response to a stimulus.

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Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special "sweet" molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization.

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Background: The present study aimed at optimization of the biotechnological production of the lignan justicidin B by genetically transformed cultures of Linum leonii and the pharmacological evaluation of the pro-apoptotic effects of the compound in HL-60 cells.

Methods: A rapidly growing selected root line of L. leonii was grown in 2-L bioreactor for period of 40 days and the protocols for obtaining of the compound have been optimized.

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This paper studies impulsive control systems with finite and infinite delays. Several stability criteria are established by employing the largest and smallest eigenvalue of matrix. Our sufficient conditions are less restrictive than the ones in the earlier literature.

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The purpose of the current Letter is to give some relations between gravitational lensing in the strong-deflection limit and the frequencies of the quasinormal modes of spherically symmetric, asymptotically flat black holes. On the one side, the relations obtained can give a physical interpretation of the strong-deflection limit parameters. On the other side, they also give an alternative method for the measurement of the frequencies of the quasinormal modes of spherically symmetric, asymptotically flat black holes.

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The present work describes fast computation methods for real-time digital filtration and QRS detection, both applicable in autonomous personal ECG systems for long-term monitoring. Since such devices work under considerable artifacts of intensive body and electrode movements, the input filtering should provide high-quality ECG signals supporting the accurate ECG interpretation. In this respect, we propose a combined high-pass and power-line interference rejection filter, introducing the simple principle of averaging of samples with a predefined distance between them.

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Real-time detection of pathological cardiac events in the electrocardiogram.

Physiol Meas

March 2007

Department of Electronics, Technical University of Sofia, 8 Kl Ohridski str, 1000, Sofia, Bulgaria.

The development of accurate and fast methods for real-time electrocardiogram (ECG) analysis is mandatory in handheld fully automated monitoring devices for high-risk cardiac patients. The present work describes a simple software method for fast detection of pathological cardiac events. It implements real-time procedures for QRS detection, interbeat RR-intervals analysis, QRS waveform evaluation and a decision-tree beat classifier.

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We have used the collisional broadening of neutral argon lines to determine the electron density and gas temperature of a microwave discharge at atmospheric pressure. The gas temperature can be obtained from the Van der Waals broadening, provided that the Stark broadening is negligible. This can be achieved by using lines from low-lying levels (close to the ground state).

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Safety investigation of team performance in accidents.

J Hazard Mater

July 2004

Department of Thermal and Nuclear Power Engineering, Technical University of Sofia, 8 Kliment Ohridski Street, Room 2356, 1797, Bulgaria.

The paper presents the capacities of the performance evaluation of teamwork (PET) method. Its practicability and efficiency are illustrated by retrospective human reliability analyse of the famous nuclear and maritime accidents. A quantitative assessment of operators' performance on the base of thermo-hydraulic (T/H) calculations and full-scope simulator data for set of NPP design basic accidents with WWER is demonstrated.

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On the solidification of a supercooled liquid droplet lying on a surface.

J Colloid Interface Sci

April 2004

Department of Mechanics, Technical University of Sofia, Branch Plovdiv, 25 Zanko Djustabanov str., 4000 Plovdiv, Bulgaria.

We model the solidification and subsequent cooling of a supercooled liquid droplet that is lying on a cold solid substrate after impact. It is assumed that solidification occurs for a given fixed droplet shape. The shapes used by the model are a sphere, truncated spheres, and an experimentally registered droplet shape.

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The influence of sucrose, wheat starch and sorbitol upon the heat- and mass-exchanging processes forming the structure of sponge cake was studied. Under the influence of wheat starch and sorbitol the structure of the sucrose-free sponge cake was formed at more uniform total moisture release. This process was done at lower temperatures and smoother change of the sponge cake height with respect to the sucrose-sweetened sponge cake.

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Transthoracic defibrillation is a procedure applying high intensity electrical current through the thorax region by electrodes, in order to simultaneously activate most of the myocardial cells, thus enforcing them to reinstate a normal rhythm. A solution is proposed for analysis and synthesis of the current density distribution field in the heart region. In an attempt to reach uniform excitation of the greatest possible quantity of myocardial cells, a field image is searched for, with the J-vector uniformity distribution as a criterion.

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A modification of the fuzzy backpropagation (FBP) algorithm called QuickFBP algorithm is proposed, where the computation of the net function is significantly quicker. It is proved that the FBP algorithm is of exponential time complexity, while the QuickFBP algorithm is of polynomial time complexity. Convergence conditions of the QuickFBP, resp.

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Adaptive filtering for artefact cancellation in motor-sensory evoked potentials using signals obtained by subtraction methods (double-stimulus, off-nerve and subthreshold) is proposed. This is advantageous as inherent non-linear distortions can be overcome in an easier way by adaptive filtering. Efficiency is assessed with reference signals synthesised by varying the shape and reducing the amplitude of a 'pure' evoked potential in the range from 10% to 50%.

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Electrical field and current distributions in electrochemotherapy.

Bioelectrochem Bioenerg

February 1999

Technical University of Sofia, Department of Electrical Engineering, Bulgaria.

Electrochemotherapy is a method for cancer treatment consisting in combining intratumor injection of cytotoxic agent with the application of intensive electrical stimuli. Thus transient cell membranes permeabilization is created, allowing the agent to better exercise its destroying effect. Positive results have been published in the treatment of cutaneous malignant formations and other types of cancer are under consideration.

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