Maria Curie Sklodowska University

www.umcs.lublin.pl
Lublin, Poland

Maria Curie-Skłodowska University was founded October 23, 1944 in Lublin. It is named in honour of Marie Curie-Sklodowska.Currently the number of students is almost 36,000. The university has 302 professors , 231 habilitated doctors, 826 senior lecturers, and 1829 teachers in total. Total staff is 3628.To meet the growing demand for higher education, the university has established branches in other cities. Wikipedia.

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Jurak M.,Maria Curie Sklodowska University
Journal of Physical Chemistry B | Year: 2013

Cholesterol is an important component of lipid rafts in mammalian cell membranes. Studies of phospholipid monolayers containing cholesterol provide insight into the role of cholesterol in regulating the properties of animal cells, raft stability, and organization. In this contribution, a study of the characteristics of binary Langmuir monolayers consisting of phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3- phosphocholine (DOPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG), and cholesterol (Chol), was conducted on the basis of the surface pressure-area per molecule (π-A) isotherms. Analysis of the results obtained provided information on the mean molecular area, the excess Gibbs energy of mixing, and condensation in the monolayer. The mixed monolayers were also deposited onto the mica plates and investigated by the contact angle measurements of water, formamide, and diiodomethane. The contact angles allowed calculating surface free energy of the films from the van Oss et al. approach. It was found that cholesterol determines the molecular packing and ordering of the monolayers closely connected with the kind of phospholipid. This is reflected in the values of surface free energy of the model membranes. From the thermodynamic analysis of phospholipid/cholesterol/liquid interactions, one may draw conclusions about the most favorable composition (stoichiometry) of the binary film which is especially important in view of the lipid rafts formation. © 2013 American Chemical Society.


Rogatko M.,Maria Curie Sklodowska University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Making use of the conformal positive energy theorem, we prove the uniqueness of four-dimensional static electrically charged black holes being the solution of Chern-Simons modified gravity equations of motion. We assume that black hole spacetime contains an asymptotically flat spacelike hypersurface with compact interior and nondegenerate components of the event horizon. © 2013 American Physical Society.


Wardak C.,Maria Curie Sklodowska University
Journal of Hazardous Materials | Year: 2011

A new polyvinylchloride membrane sensor for Pb2+ with solid contact based on ionic liquid has been prepared. The electrode shows a Nernstian response for lead ions over a wide concentration range (1×10-8 to 1×10-1molL-1) and the slope of 29.8mV/decade. The limit of detection is 4.3×10-9molL-1. It has a fast response time of 5-7s and can be used for 4 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 3.5-7.3 and shows a very good discriminating ability towards Pb2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied as an indicator electrode in potentiometric titration of lead ions with K2CrO4 and for direct determination of Pb2+ ions in real sample solution. © 2010 Elsevier B.V.


In the article, a new integrated kinetic Langmuir equation (IKL) is derived. The IKL equation is a simple and easy to analyze but complete analytical solution of the kinetic Langmuir model. The IKL is compared with the nth-order, mixed 1,2-order, and multiexponential kinetic equations. The impact of both equilibrium coverage θ eq and relative equilibrium uptake u eq on kinetics is explained.Anewly introduced Langmuir batch equilibrium factor f eq that is the product of both parameters θ equ eq is used to determine the general kinetic behavior. The analysis of the IKL equation allows us to understand fully the Langmuir kinetics and explains its relation with respect to the empirical pseudo-first-order (PFO, i.e., Lagergren), pseudo-second-order (PSO), and mixed 1,2-order kinetic equations, and it shows the conditions of their possible application based on the Langmuir model. The dependence of the initial adsorption rate on the system properties is analyzed and compared to the earlier published approximate equations. © 2010 American Chemical Society.


Kloskowski J.,Maria Curie Sklodowska University
Oikos | Year: 2012

In anthropogenic landscapes animals may be lured into low-quality habitats where they survive or reproduce poorly ('ecological traps'). I investigated breeding habitat selection in relation to intra-seasonal changes in food availability and reproductive output in red-necked grebes Podiceps grisegena, a size-limited predator, of common carp Cyprinus carpio ponds. Carp farms constitute highly heterogeneous habitat mosaics due to separate stocking of different age/size fish. Pond features significant for grebe settling decisions, i.e. hydroperiod and emergent vegetation cover, had no obvious effects on prey abundance for chicks and on fledging success. Breeding grebes avoided ponds containing fish too large for them to ingest but exhibited little preference between ponds with medium-sized one-year-old carp that could be exploited by pre-laying birds, and ponds designated for young-of-the-year carp, where only invertebrates and amphibians were available as prey in early spring. Red-necked grebes settling on ponds with medium-sized fish failed to predict future shifts in interactions with carp stocks; carp exceeded the prey-size threshold of chicks and adversely affected their non-fish prey levels. The resulting food shortage led to severe egg-to-fledging mortality rates compared to fishless ponds or those containing young-of-the-year fish. This study shows that waterbirds vulnerable to competition from fish can risk maladaptive habitat selection due to unrecognised spatial and temporal variation in food resources caused by fish stocking practices. Ecological traps created by perturbations to trophic interactions may be common but difficult to detect because altered dynamics of trophic resources can affect wildlife indirectly. As with other types of ecological traps, manipulation of habitat features identified as attractive cues for settling animals, but not related to critical food resources, may help to reduce perceptual pitfalls. For example, wetland management to mitigate trap effects driven by commercially stocked fish should preserve abundant emergent vegetation in habitats with weak fish impact and extend their hydroperiod. © 2012 The Authors.


Podgorski M.,Maria Curie Sklodowska University
Dental Materials | Year: 2012

Objectives: In this study five novel dimethacrylates of different chain lengths having rigid aromatic rings were synthesized and proposed as possible dental monomers for dental resin mixtures. Methods: Four monomers were prepared by the reaction of glycidyl methacrylate with dicarboxylic acid esters obtained from phthalic anhydride and 1,3-propylene, 1,4-butylene, 1,5-penthylene and 1,6-hexylene glycols. The addition reaction of glycidyl methacrylate and the acidic compound was carried out in the presence of tetraethylammonium bromide. The fifth monomer was obtained from 1,5-penthylene glycol-based dimethacrylate by blocking its hydroxyl groups with acetyl groups. The monomers were photo-copolymerized with triethyleneglycol dimethacrylate (TEGDMA) in the presence of a photoinitiator which was 2,2-dimethoxy-2-phenyloacetophenone. Unfilled polymers were evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. The prepared polymers were also subjected to dynamic mechanical studies (DMA). Results: Results show that, increasing the distance between double bonds decreases flexural modulus and hardness. As expected, the curing shrinkage increased with increasing degree of conversion. The acetylation of hydroxyl groups resulted in improved water uptake properties of the compositions. It was demonstrated that, depending upon the content of acetyl groups in the network, the glass transition temperature may be significantly lowered. In polymers with large amounts of pendant groups, β relaxation overlaps with α relaxation (glass transition temperature), and it is the former that discloses the maximum on the tan δ curve. Significance: The systematic change in the length of the new dimethacrylates provided insight into the effects on the resultant material properties. It was shown in the article that the properties of the new monomers compare favorably with properties of the commercially available resins. © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.


Podgorski M.,Maria Curie Sklodowska University
Dental Materials | Year: 2010

Objective: In this study three novel dimethacrylates of different chain lengths having bulky bicycloaliphatic rings were synthesized and proposed as possible dental monomers for dental resin mixtures. Methods: The monomers were prepared by the reaction of glycidyl methacrylate with dicarboxylic acid esters obtained from nadic anhydride and ethylene, 1,4-butylene and 1,6-hexylene glycols. The addition reaction of glycidyl methacrylate and the acidic compound was carried out in the presence of basic catalyst-tetraethylammonium bromide. The monomers were photopolymerized in the presence of a photoinitiator which was 2,2-dimethoxy-2-phenyloacetophenone. Unfilled homopolymers were evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. The prepared polymers were also subjected to dynamic mechanical studies (DMA). Results: The proposed dimethacrylates exhibit low curing shrinkage (about 4-5%) and high degree of double bond conversion (up to 84%). Their water sorption and water solubility are comparable to those of Bis-GMA composite resin. Furthermore, their thermo-mechanical properties are better than those of the commonly known dimethacrylates. Significance: The new dimethacrylates are promising photocurable dental monomers owning to simple synthesis, high degree of conversion coupled with low curing shrinkage and good mechanical properties. © 2010 Academy of Dental Materials.


Zdziennicka A.,Maria Curie Sklodowska University
Langmuir | Year: 2010

In this Article, the surface behavior of mixtures of nonionic Triton X-165 (TX-165) with methanol, ethanol, and propanol at constant Triton X-165 concentration in the range from 1 x 10-7 to 10-3 M in aqueous solutions was investigated by surface tension measurements of their solutions in a wide range of alcohol concentrations. The obtained values of the surface tension of solutions were compared with, those calculated from. Szyszkowski, Connors, and Fainerman and Miller equations. On the basis of the surface tension data, the Triton X-165 and alcohol concentrations at water-air interface and. their standard free energy of adsorption as well as the composition of the monolayer at this interface were determined. Taking into account this composition and activity coefficient of Triton X-165 and alcohol, the free entalphy of their mixing was also calculated. From the measurements and. calculations, it results, among other things, that unexpectedly the Fainerman and. Miller equation derived for ideal mixtures of homologous surfactant can be useful for the description of changes of the solution surface tension of the investigated mixtures and that the amount of short chain alcohols at the water-air interface at their low concentration in the bulk phase is proportional to the activity coefficient. © 2009 American Chemical Society.


Krawiec M.,Maria Curie Sklodowska University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

A structural model of Au induced Si(553) surface is proposed. The model is based on the recently revised value of Au coverage of 0.48 monolayers, which suggests the formation of two gold chains on each Si(553) terrace. The resulting structural model, such as the models of other vicinal Si surfaces, features the honey-comb chain, but no buckling of the step edge is observed, unlike in the case of the Si(335)-Au and Si(557)-Au surfaces. The present model is more stable than the models with single Au chain only, and agrees well with existing experimental data. In particular, calculated band structure, featuring two metallic bands coming from the hybridization of gold in both chains with neighboring Si atoms, matches well the photoemission data. Moreover, theoretical scanning tunneling microscopy topographs remain in good agreement with the experiment. © 2010 The American Physical Society.


Grzadka E.,Maria Curie Sklodowska University
Cellulose | Year: 2011

The adsorption of carboxymethylcellulose (CMC) in the presence or absence of the surfactants: anionic SDS, nonionic Triton X-100 and their mixture SDS/TX-100 from the electrolyte solutions (NaCl, CaCl2) on the alumina surface (Al2O3) was studied. In each measured system the increase of CMC adsorption in the presence of surfactants was observed. This increase was the smallest in the presence of SDS, a bit larger in the presence of Triton X-100 and the largest when the mixture of SDS/Triton X-100 was used. These results are a consequence of formation of complexes between the CMC and the surfactant particles. Moreover, the dependence between the amount of surfactants' adsorption and the CMC initial concentration was measured. It comes out that the surfactants' adsorption amount is not dependent on the CMC initial concentration and moreover, it is unchanged in the whole measured concentration range. The influence of kind of electrolyte, its ionic strength as well as pH of a solution on the amount of the CMC adsorption at alumina surface was also measured. The amount of CMC adsorption is larger in the presence of NaCl than in the presence of CaCl2 as the background electrolyte. It is a result of the complexation reaction between Ca2+ ions and the functional groups of CMC belonging to the same macromolecule. As far as the electrolyte ionic strength is concerned the increase of CMC adsorption amount accompanying the increase of electrolyte ionic strength is observed. The reason for that is the ability of electrolyte cations to screen every electrostatic repulsion in the adsorption system. Another observation is that the increase of pH caused the decrease of CMC adsorption. The explanation of this phenomenon is connected with the influence of pH on both dissociation degree of polyelectrolyte and kind and concentration of surface active groups of the adsorbent. © 2011 Springer Science+Business Media B.V.

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