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Search Results: 1 - 10 of 32 matches for " Andreana STOYKOVA-KANALIEVA "
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Scientific Annals of the Alexandru Ioan Cuza University of Iasi : Economic Sciences Series , 2010,
Abstract: In the current economic situation the comparison of the degree of economic development be-tween the countries in United Europe is becoming more up-to-date. New approaches and tools for such comparison are being developed.This article offers a possible approach, focusing on the statistic analysis of growth and differ-ences. It is based on the modification of this method of analysis, proposed by V. Tzonev and T. Kunaliev. The method has been adapted for the needs of international comparative analyses in order to compare the GVA growth (Gross Value Added) based on growth sources in R. Bulgaria and R. Romania for the period from 2002 to 2007. The adjusted method is (has been) applied in three directions of analysis, focusing on their cognitive values. This specific comparative study has taken them into consideration, interpreting in details the obtained results.
Isotropic shear bond strength behavior of superficial bovine dentin: A pilot study  [PDF]
Camila Sabatini, Sebastiano Andreana
Open Journal of Stomatology (OJST) , 2013, DOI: 10.4236/ojst.2013.31001

The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovine coronal dentin (n = 20) with a two-step etch-and-rinse adhesive (Optibond Solo Plus) and resin composite (Z100). Shear bond strength was evaluated at 24 h and failure modes of representative specimens wereobserved with FE-SEM. Non-parametric Kruskal-Wallis test with a significance level of 0.05 was used for data analysis. Mean shear bond strength values for the incisal, middle, and cervical thirds were 36.9 (3.1), 42.6 (2.6), and 37.1 (2.1) respectively with no significant differences evidenced between the crown thirds (p = 0.19). Observation of the failure mode of representative specimens demonstrated that specimens with high bond strength values exhibited predominantly mixed-type failures whereas low strength specimens exhibited adhesive failures between the dentin and adhesive. The absence of significant differences in shear bond strength between crown thirds indicate that, regardless of tubule orientation, any crown region can be used when superficial bovine incisor dentin is used for shear bond strength testing.

Surface preparation and isotropic shear bond strength properties of superficial bovine dentin  [PDF]
Camila Sabatini, Sebastiano Andreana, Zhe Wu
Open Journal of Stomatology (OJST) , 2013, DOI: 10.4236/ojst.2013.34046

The effect of different types of surface preparation with SiC abrasive paper on the shear bond strength (SBS) of superficial bovine dentin obtained from the incisal, middle and cervical thirds were evaluated. Dentin substrates were obtained with twenty specimens for each locationgrit combination. Superficial dentin was exposed and prepared to 120-, 320-, or 600-grit SiC; the dentin surfaces were treated with Optibond Solo Plus (Kerr) and polymerized for 20 s. The specimens were placed in a jig, filled with resin composite Z100 (3M-ESPE), polymerized for 40 s according to manufacturer’s instructions, and stored for 24 h at 37℃ and 100% humidity. After 24 h, SBS was measured using a loading testing machine (Ul-tradent) and expressed in megapascals. A two-way ANOVA and Tukey test were used for data analysis. No statistically significant effect of the location (P = 0.254) or interaction grit-location (P = 0.629) were observed on SBS. Statistically significant effect of the grit on the SBS was detected (P < 0.001) with 320-grit being statistically different from 600-grit (P = 0.011) and 120-grit (P < 0.001). No significant differences were observed between 600-grit and 120-grit (P = 0.413). Regardless of the location, 320-grit consistently showed the lowest SBS indicating that different surface grit preparations have an effect on dentin SBS values.

Er81 is a downstream target of Pax6 in cortical progenitors
Tran Tuoc, Anastassia Stoykova
BMC Developmental Biology , 2008, DOI: 10.1186/1471-213x-8-23
Abstract: We identified and analyzed the regulatory function of an evolutionarily conserved upstream DNA sequence in the putative mouse Er81 promoter. Three potential Pax6 binding sites were identified in this region. We found that the presence of one of these sites is necessary and sufficient for full activation of the Er81 promoter in Pax6-transfected HeLa cells, while other still unknown factors appear to contribute to Er81 promoter activity in cortical progenitors and neuronal cells. The results suggest that endogenous Pax6, which is expressed at the highest level in progenitors of the rostrolateral cortex, exerts region-specific control of Er81 activity, thus specifying a subpopulation of layer 5 projection neurons.We conclude that the genetic interplay between the transcription factors, Pax6 and Er81, is responsible, in part, for the regional specification of a distinct sublineage of layer 5 projection neurons.In the mammalian neocortex (pallium), neurons with striking morphological and functional diversity are organized radially in six layers, and tangentially into numerous functional domains. Only recently have the molecular and cellular mechanisms that guide the process of corticogenesis responsible for this organization begun to be resolved [1,2]. The main source of cortical projection neurons is the population of pluripotent radial glial progenitors (RG), which divide asymmetrically at the apical surface of the ventricular zone (VZ) and generate both neuronal and glial progeny [3]. After midgestation, RG generate neuronal progenitors, termed intermediate or basal progenitors (BPs), that divide symmetrically at the basal surface of the VZ and in the subventricular zone (SVZ). Thus, while the asymmetric division of RG progenitors gives rise to progeny with distinct cell fates, the symmetric division of BPs primarily modulates the number of cells in previously established neuronal cell lineages [4]. The projection neurons of the lower (6 and 5) and upper (4–2) layers
Bulgarian Society of Individual Psychology
Zhaneta Stoykova,Tiha Delcheva
Psychological Thought , 2013, DOI: 10.5964/psyct.v6i1.59
Abstract: It has been two years since the Bulgarian Society of Individual Psychology was founded on the initiative of Trakia University faculty membersand students. On the occasion of its first anniversary, the goals of the Society and its activity over the course of the last year will be presentedin this article.
Why Sociology Has a Marginal Position in Civic Education in Bulgaria Nationally Specific and/or Universal Trends
Georgi Dimitrov,Elena Stoykova
Journal of Social Science Education , 2009,
Abstract: The authors claim that, to an extent, the marginalization is a by-product of relationship among sociology, citizenship education and school education in general. This relationship is pretty complex and problematic because each of the three constituents undergoes a phase of fundamental crisis of axiological and institutional character. The developments in American sociology that exemplifies the state of affairs in the field are taken as point of departure while the Bulgarian case is used just as a magnifying glass to see clearer the triple crises which bring us to the roots of the civilizational transformation experienced today.The moral of the story is that sociology has been marginalized in last decades because its public and academic status won by the previous generation can not be taken for granted. It does not correspond to the pressing demands of the changing world for a different type of sociology. Thus sociology falls easy prey to the academic competitors who follow aggressive strategy and policy of public expansion even in civil education. The particular situation in other countries may be different but these are common general rules of construing sociology. At the end the paper offers some guidelines for transformation of the pattern in which contemporary sociology should be practiced in order to raise its public and civic relevance through refocusing it on sophisticated mediation of public policy and actions of citizens and through new forms of cultural communication.
Vascular Functions and Brain Integrity in Midlife: Effects of Obesity and Metabolic Syndrome
Andreana P. Haley
Advances in Vascular Medicine , 2014, DOI: 10.1155/2014/653482
Abstract: Intact cognitive function is the best predictor of quality of life and functional ability in older age. Thus, preventing cognitive decline is central to any effort to guarantee successful aging for our growing population of elderly. The purpose of the work discussed in this outlook paper is to bridge knowledge from basic and clinical neuroscience with the aim of improving how we understand, predict, and treat age- and disease-related cognitive impairment. Over the past six years, our research team has focused on intermediate neuroimaging phenotypes of brain vulnerability in midlife and isolating the underlying physiological mechanisms. The ultimate goal of this work was to pave the road for the development of early interventions to enhance cognitive function and preserve brain integrity throughout the lifespan. 1. Introduction The most rapidly rising threat to brain health in US adults is the clustering of obesity, high blood pressure, elevated fasting glucose, and abnormal lipid metabolism in a single individual, a condition known as metabolic syndrome. A staggering 34–45% of US adults currently fulfill criteria for metabolic syndrome [1]. These numbers are alarming as metabolic syndrome is associated not only with increased risk for cardiovascular disease and diabetes [2], but also with current cognitive dysfunction and risk for future cognitive decline, over and above the detrimental effects of its components [3–10]. While we have some information about each of the disrupted peripheral physiological mechanisms in turn, very little is known about the central mechanisms that connect metabolic syndrome to brain health and cognition. The goal of our work over the past six years has been to explore the underlying neural mechanisms of midlife brain vulnerability related to peripheral vascular and metabolic disturbances, before clinically significant and permanent cognitive dysfunction has developed. Understanding the preclinical stages of disease has the enormous advantage of presenting opportunities for early intervention, a task with much higher prospect of success than attempting to restore lost function later in life. Early identification of brain vulnerability is crucial; yet it presents a significant challenge due to the low sensitivity of clinical paper-and-pencil measures of cognitive impairment and lack of norms for tests with higher ceiling performance values. Our team has endeavored to solve this problem through combining sophisticated behavioral analyses with modern neuroimaging techniques. 2. Early Markers of Brain Vulnerability As noted
(S)-N-[(4-{(S)-1-[2-(4-Methoxybenzamido)-2-methylpropanoyl]pyrrolidine-2-carboxamido}-3,4,5,6-tetrahydro-2H-pyran-4-yl)carbonyl]proline dimethyl sulfoxide monosolvate (4-MeBz-Aib-Pro-Thp-Pro-OH)
Svetlana A. Stoykova,Anthony Linden,Heinz Heimgartner
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536813004546
Abstract: The asymmetric unit of the title compound, C28H38N4O8·C2H6OS, contains one tetrapeptide and one disordered dimethyl sulfoxide (DMSO) molecule. The central five-membered ring (Pro2) of the peptide molecule has a disordered envelope conformation [occupancy ratio 0.879 (2):0.121 (2)] with the envelope flap atom, the central C atom of the three ring methylene groups, lying on alternate sides of the mean ring plane. The terminal five-membered ring (Pro4) also adopts an envelope conformation with the C atom of the methylene group closest to the carboxylic acid function as the envelope flap, and the six-membered tetrahydropyrane ring shows a chair conformation. The tetrapeptide exists in a helical conformation, stabilized by an intramolecular hydrogen bond between the amide N—H group of the heterocyclic α-amino acid Thp and the amide O atom of the 4-methoxybenzoyl group. This interaction has a graph set motif of S(10) and serves to maintain a fairly rigid β-turn structure. In the crystal, the terminal hydroxy group forms a hydrogen bond with the amide O atom of Thp of a neighbouring molecule, and the amide N—H group at the opposite end of the molecule forms a hydrogen bond with the amide O atom of Thp of another neighbouring molecule. The combination of both intermolecular interactions links the molecules into an extended three-dimensional framework.
Pattern Projection with a Sinusoidal Phase Grating
Elena Stoykova,Jana Harizanova,Ventseslav Sainov
EURASIP Journal on Advances in Signal Processing , 2008, DOI: 10.1155/2009/351626
Abstract: The aim of this work is to study the diffractive properties of a sinusoidal phase grating for incorporation as a pattern projection element in a multisource and multicamera phase-shifting profilometric system. Two challenges should be overcome for successful operation of such a system, which are connected to inherent limitations of the phase-shifting algorithm ¢ € ”requirements for a sinusoidal fringe profile and for equal background and contrast of fringes in the recorded patterns. As a first task, we analyze the frequency content of the projected fringes in the Fresnel diffraction zone for parallel and divergent light illumination at different grating parameters and wavelengths. As a second task, we evaluate the systematical errors due to higher harmonics and multiwavelength illumination. Finally, operation of the four-wavelength profilometric system is simulated, and the error of the profilometric measurement evaluated. The results of test measurements are also presented.
Luminescence of Speleothems in Italian Gypsum Caves: Preliminary Report
Yavor Y. Shopov,Diana Stoykova,Paolo Forti
Physics , 2009,
Abstract: The luminescence of 3 speleothem samples from the Acquafredda karst system and 1 from the Novella Cave (Gessi Bolognesi Natural Park, Italy) has been recorded using excitation by impulse Xe- lamp. All these carbonate speleothems are believed to be formed only from active CO2 from the air, because the bedrock of the cave consist of gypsum and does not contain carbonates. The obtained photos of luminescence record the climate changes during the speleothem growth. U/Th and 14C dating proved that studied speleothems started to grow since about 5,000 years ago. The detailed analyses of the luminescence records is still in progress.
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