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Search Results: 1 - 10 of 1275 matches for " Alexandru Voicu "
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The Epistemological Structure in the Theories of International Relations
Alexandru Voicu
Sfera Politicii , 2012,
Abstract: Review of: Martin HOLLIS, Steve SMITH, Explaining and Understanding
Comparative Analysis of Emerging Green Certificate Markets from a Computable General Equilibrium Perspective
Cristina GALALAE,Alexandru VOICU
Economia : Seria Management , 2011,
Abstract: Whether using market mechanisms to allocate green certificates in various countries is an optimal solution for stimulating green electricity production represents a question proposed by numerous recent comparative analyses, with opinions being split. Our paper proposes a differing perspective, employing modern computational economics techniques in order to study if general equilibrium is achievable, nationally and internationally, and how it compares with the non-market steady state. We analyse the field, determining exogenous and endogenous factors of influence that we cast into functional relationships via econometric estimation. Subsequently, we study four multi-period general equilibrium models, recursive and non-recursive, solving the latter ones via a Johansen/Euler method for simultaneous all-year computation. General equilibrium is shown to be achievable but dependent on country specific conditions, with optimality being relative in a globalised context. In closing, we present a case study focused on providing useful guidelines for future international marketing efforts in this domain.
Solving a Supply Chain Management Problem to Near Optimality Using Ant Colony Optimization, in an International Context
Lumini?a Nicolescu,Cristina Galalae,Alexandru Voicu
Amfiteatru Economic , 2013, DOI: 1234567
Abstract: The importance of achieving optimality or near optimality in supply routing is on the rise as globalization leads to scenarios in which multiple, heterogeneous and highly spatially distributed demands have to be satisfied under stringent constraints. However, there is no consensus concerning what constitutes an all-encompassing objective function for the supply planner, who faces what can easily constitute a problem requiring Non-deterministic Polynomial time for determining the solution even in its simplest formulations. The work presented in this article proposes a mathematically grounded approach that uses Ant Colony Optimisation to yield near optimal results across a large set of problem formulations and objective functions. The latter are designed to capture real-world goals such as cost reduction, optimal transportation management, flexibility and minimal lead-time. This study adds a new dimension to topics traditionally encountered in the literature, namely that of the cultural differences between partners engaged in international trade relations. Furthermore, the impact of the lag between determining and implementing the quasi-optimal strategy is forecast for an array of objective functions tailored to represent approaches encountered in international companies dealing with supply challenges in fields such as Information Technology. Finally, the framework thus established is employed to analyse the indirect relationship between Asian “white box” suppliers and a Romanian firm operating in Mobile Integrated Device space.
NANOTECHNOLOGICAL SOLUTION FOR IMPROVING THE ANTIBIOTIC EFFICIENCY AGAINST BIOFILMS DEVELOPED BY GRAM-NEGATIVE BACTERIAL STRAINS
Ani Ioana Cotar,Alexandru Mihai Grumezescu,Ecaterina Andronescu,Georgeta Voicu
Letters in Applied NanoBioScience , 2013,
Abstract: At present bacteria involved in biofilm associated infections display the highest rates of antibiotic resistance among pathogenic bacteria, which made that treatment options to be limited, and determined the researchers to find out alternative treatments to antibiotics. In the recent years nanomaterials gained much attention in medicine, particularly in the fight to bacteria resistant to antibiotics by acting as drug delivery devices. Magnetic iron oxide nanoparticles (MNPs) have raised much interest during the recent years due to their potential applications in medicine. In the present study we synthesized MNPd functionalized with antibiotics for the study of their antimicrobial and anti-biofilm properties against Escherichia coli and Pseudomonas aeruginosa, two Gram-negative bacteria, frequently resistant to antibiotics, involved in biofilm infections in order to investigate their capacity to serve as potential drug delivery systems in the fight to these important opportunist pathogens.
Cognitive Impairment in Chronic Obstructive Pulmonary Disease
Alexandru F. Cri?an, Cristian Oancea, Bogdan Timar, Ovidiu Fira-Mladinescu, Alexandru Cri?an, Voicu Tudorache
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102468
Abstract: Background/Purpose Chronic obstructive pulmonary disease (COPD), especially in severe forms, is commonly associated with multiple cognitive problems. Montreal Cognitive Assessment test (MoCA) is used to detect cognitive impairment evaluating several areas: visuospatial, memory, attention and fluency. Our study aim was to evaluate the impact of stable COPD and exacerbation (AECOPD) phases on cognitive status using MoCA questionnaire. Methods We enrolled 39 patients (pts), smokers with COPD group D (30 stable and 9 in AECOPD) and 13 healthy subjects (control group), having similar level of education and no significant differences regarding the anthropometric measurements. We analyzed the differences in MoCA score between these three groups and also the correlation between this score and inflammatory markers. Results Patients with AECOPD had a significant (p<0.001) decreased MoCA score (14.6±3.4) compared to stable COPD (20.2±2.4) and controls (24.2±5.8). The differences between groups were more accentuated for the language abstraction and attention (p<0.001) and delayed recall and orientation (p<0.001) sub-topics. No significant variance of score was observed between groups regarding visuospatial and naming score (p = 0.095). The MoCA score was significantly correlated with forced expiratory volume (r = 0.28) and reverse correlated with C-reactive protein (CRP) (r = ?0.57), fibrinogen (r = ?0.58), erythrocyte sedimentation rate (ESR) (r = ?0.55) and with the partial pressure of CO2 (r = ?0.47). Conclusions According to this study, COPD significantly decreases the cognitive status in advanced and acute stages of the disease.
Effect of the Spin-Spin Interaction on the Coulomb’s Law: Application to Ferromagnetism  [PDF]
Voicu Dolocan, Voicu Octavian Dolocan
World Journal of Condensed Matter Physics (WJCMP) , 2012, DOI: 10.4236/wjcmp.2012.23019
Abstract: In this work we present a model for the determination of the interaction energy for triplet and singlet states in atoms with incomplete filled shells. Our model includes the modification of the Coulomb’s law by the interaction between the magnetic moments of the electrons. We find that the energy of the triplet state is lower than the energy of the singlet state. We calculate the interaction energy between the electrons from the adjacent atoms in fcc lattices and we find that the minimum interaction energy is attained for the triplet state. The result is presented for the interaction between the electrons of the first coordination group and those of the second coordination group. The interaction energy which aligns the spins is used to evaluate the Curie temperature in a mean field model.
Optimized Anti-pathogenic Agents Based on Core/Shell Nanostructures and 2-((4-Ethylphenoxy)ethyl)-N-(substituted-phenylcarbamothioyl)-benzamides
Carmen Limban,Alexandru Mihai Grumezescu,Crina Saviuc,Georgeta Voicu,Gentiana Predan,Robert Sakizlian,Mariana Carmen Chifiriuc
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms131012584
Abstract: The purpose of this study was to design a new nanosystem for catheter surface functionalization with an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 colonization and subsequent biofilm development . New 2-((4 ethylphenoxy)methyl)- N-(substituted-phenylcarbamothioyl)-benzamides were synthesized and used for coating a core/shell nanostructure. Their chemical structures were elucidated by NMR, IR and elemental analysis, being in agreement with the proposed ones. Fe 3O 4/C 12 of up to 5 nm size had been synthesized with lauric acid as a coating agent and characterized by XRD, FT-IR, TGA, TEM and biological assays. The catheter pieces were coated with the fabricated nanofluid in magnetic field. The microbial adherence ability was investigated in 6 multiwell plates by using culture based methods and Scanning Electron Microscopy (SEM). The nanoparticles coated with the obtained compounds 1a– c inhibited the adherence and biofilm development ability of the S. aureus and P. aeruginosa tested strains on the catheter functionalized surface, as shown by the reduction of viable cell counts and SEM examination of the biofilm architecture. Using the novel core/shell/adsorption-shell to inhibit the microbial adherence could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.
Magnetite nanoparticles influence the efficacy of antibiotics against biofilm embedded Staphylococcus aureus cells
Ani Ioana Cotar,Alexandru Mihai Grumezescu,Keng-Shiang Huang,Georgeta Voicu
Biointerface Research in Applied Chemistry , 2013,
Abstract: The expansion of bacterial antibiotic resistance is a growing problem today, and has determined the intensification of studies for finding out new alternatives to antibiotic treatment. The purpose of this study was to investigate the potential of magnetite nanoparticles (Fe3O4) to achieve a sustained and controlled drug release and subsequently improve the efficacy of antibiotics against Staphylococcus aureus, one of the most frequently isolated opportunistic pathogens, responsible for severe infections in immunocompromised patients with indwelling catheters or other biomedical devices. The obtained results showed that Fe3O4 nanoparticles functionalized with different antibiotics exhibited an inhibitory activity on growth and the biofilm formation of S. aureus strain superior to that exhibited by each antibiotic alone. The studied magnetic nanoparticles could act as efficient antibiotic potentiators and delivery systems for combating S. aureus biofilms on biomedical devices or human tissues.
How sociability and trust impact on welfare attitudes. A cross-european analysis
Bogdan VOICU,Malina VOICU
Revista de Cercetare ?i Interven?ie Social? , 2011,
Abstract: The bulk of the literature investigating the connection between social capital and the welfare state explores the impact of the latter one on various manifestations of the first one. The tested assumption is therefore usually related to the effects of the institutional arrangements on the existing resources. Our paper proposes a different approach, focusing on the effects of four social capital indicators on very general attitudes towards the welfare state. Using multilevel models, we show that the less formalized manifestations of social capital are negatively related to the support for a broader welfare state, while for the more formal ones the opposite holds true. Considering the relations between the welfare culture and the shape of the welfare state (as described in the literature), and our findings, we conclude that the institutional arrangements represent both a factor which models social capital, as well as a consequence of the latter one.
On the Fundamental Equations of Electromagnetism in Finslerian Spacetimes
Nicoleta Voicu
PIER , 2011, DOI: 10.2528/PIER10122108
Abstract: In spaces with Finslerian geometry, the metric tensor depends on the directional variable, which leads to a dependence on this variable of the electromagnetic tensor and of the 4-potential. In this paper, we investigate some of the consequences of this fact, regarding the basic notions and equations of classical electromagnetic field theory.
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