Integrated Information System for Demographic Statistics 'ESGRAON-TDS' in Bulgaria

In this paper we describe the Bulgarian statistical system that provides unique research possibilities for demographic analyses. In particular, we review the methodology, structure and informational flows for population registration and the registration of vital events in Bulgaria. In addition, we describe the main elements of the most recent Bulgarian census from March 1, 2001. In the last part of the paper, we pay special attention to data protection and data confidentiality issues in Bulgaria.Bulgaria, census, demographic statistics, statistics

PRACTICAL APPLICATION OF QSAR TECHNIQUE FOR PREDICTION OF BIOLOGICAL ACTIVITY OF SELECTED HYDRAZONES

One important class of organic compounds is hydrazones which find huge application in many scientific areas. They demonstrate fascinating biological activities like as antioxidant, anti-inflammatory, anticonvulsants, antidepressant, anxiolytic, antihypertensive, anticancer, antimicrobial, anti-tuberculosis, and antifungal activity. This wide palette of the useful medical properties has attracted considerable scientific interest for their synthesis. The biological activity and the changes in this activity depend on the substituents present in the hydrazone molecule. The hydrazones can be used in agriculture as herbicides, insecticides, and plant growth stimulants because of their physiological properties. A series of substituted aromatic hydrazones have been synthesized and evaluated for in vitro antimicrobial activity against: Bacillus subtilis. QSAR study was performed to estimate the quantitative effects of the selected descriptors of derivatives on their antibacterial activity. Topological and physicochemical descriptors were calculated for each molecule and a several two-parametric mathematical models have been selected for further discussion. The statistical significance of each model was measured by a few cross-validation parameters (Q, PRESS/SSY; SPRESS; PSE andQ2). Statistical evaluation of the data used to test the quality of the obtained models, indicated that in statistically significant model both parameters AC (Atom count) and MAPA (Maximal projection area) have opposite input to the modeling of biological activity of the selected hydrazones. Following statistical parameters were obtained for this model: R2 = 0.9444; Sd = 0.0097; F-test = 101.9875; R2adj = 0.9352; Q = 100.1858; PRESS/SSY = 0.0564; SPRESS = 0.0098; PSE = 0.0088 and Q2 = 0.9436

Dynamics of nearly spherical vesicles in an external flow

We analytically derive an equation describing vesicle evolution in a fluid where some stationary flow is excited regarding that the vesicle shape is close to a sphere. A character of the evolution is governed by two dimensionless parameters, $S$ and $\Lambda$, depending on the vesicle excess area, viscosity contrast, membrane viscosity, strength of the flow, bending module, and ratio of the elongation and rotation components of the flow. We establish the ``phase diagram'' of the system on the $S-\Lambda$ plane: we find curves corresponding to the tank-treading to tumbling transition (described by the saddle-node bifurcation) and to the tank-treading to trembling transition (described by the Hopf bifurcation).Comment: 4 pages, 1 figur

ANTIMICROBIAL EVALUATION OF SOME HYDRAZONE DERIVATIVES

Hydrazone derivatives represent one of the most active classes of compounds possessing a broad spectrum of biological activity. The use of the hydrazones is due to their anti-inflammatory, antimicrobial, antidepressant, antitumoral, analgesic, antiplatelet, anticonvulsant, antischistosomiasis and antiviral activity. Due to their physiological activity, they are also used in agriculture as herbicides, insecticides, fungicides and plant growth regulators. Furthermore, hydrazone derivatives possessing an azomethine proton (-NH-N=CH-) constitute a significant class of compounds for new drug development in order to synthesize effective agents against microbial activity. Considering these applications some psubstituted aromatic hydrazones were previously synthesized and characterized. In this study a series of aromatic hydrazones were evaluated for their in vitro growth and inhibitory activity against Bacillus subtilis, Aspergillus niger and Candida utilis, using filter paper disc method. Stock solutions of compounds were prepared in DMSO, as inert medium in three different concentration levels: 1, 5 and 10 mg/mL. A control disc using DMSO without any test compound was included and there was no inhibitory activity in those disks. The diameter of zone of inhibition (mm) was measured. Every test was done in triplicate to confirm the findings. The screening results indicate that not all investigated compounds exhibited antimicrobial activities. It can be noted that compounds with N-p-methoxy substitute group showed the greatest inhibitory effect against Bacillus subtilis (max zone of inhibition of 14.3 mm) and Candida utilis (max zone of inhibition of 16 mm). All investigated hydrazones showed no inhibitory effects against Aspergillus niger

Modulating membrane shape and mechanics of minimal cells by light: area increase, softening and interleaflet coupling of membrane models doped with azobenzene-lipid photoswitches

Light can effectively interrogate biological systems providing control over complex cellular processes. Particularly advantageous features of photo-induced processes are reversibility, physiological compatibility, and spatiotemporal precision. Understanding the underlying biophysics of light-triggered changes in bio-systems is crucial for cell viability and optimizing clinical applications of photo-induced processes in biotechnology, optogenetics and photopharmacology. Employing membranes doped with the photolipid azobenzene-phosphatidylcholine (azo-PC), we provide a holistic picture of light-triggered changes in membrane morphology, mechanics and dynamics. We combine microscopy of giant vesicles as minimal cell models, Langmuir monolayers, and molecular dynamics simulations. We employ giant vesicle elelctrodeformation as a facile and accurate approach to quantify the magnitude, reversibility and kinetics of light-induced area expansion/shrinkage as a result of azo-PC photoisomerization and content. Area increase as high as ~25% and a 10-fold decrease in the membrane bending rigidity is observed upon trans-to-cis azo-PC isomerization. These results are in excellent agreement with simulations data and monolayers. Simulations also show that trans-to-cis isomerization of azo-PC decreases the membrane leaflet coupling. We demonstrate that light can be used to finely manipulate the shape and mechanics of photolipid-doped minimal cell models and liposomal drug carriers, thus, presenting a promising therapeutic alternative for the repair of cellular disorders.Competing Interest StatementThe authors have declared no competing interest