74 research outputs found
Poszukiwanie aktywnych związków fotouczulających pod kątem ich aplikacji w fotodynamicznej diagnostyce i terapii nowotworowej
Celem pracy była charakterystyka sześciu nowych, nie badanych wcześniej,
fotouczulaczy z grupy chloryn, które zaprojektowano i zsyntezowano z myślą
o potencjalnym zastosowaniu w diagnostyce i terapii fotodynamicznej. Aby poprawić
ich powinowactwo do komórek nowotworowych, do części z nich przyłączono
fragmenty cukrów. W makroskali pozwala to na wykorzystanie wzmożonego
metabolizmu i zwiększonej glikolizy szybko proliferujących komórek nowotworowych
do wybiórczego transportu związków. W skali bardziej lokalnej umożliwia specyficzne
oddziaływanie z komórkami nowotworowymi za pośrednictwem wiążących cukier
receptorów lektynowych. Badania wykonane w ramach pracy miały charakter badań podstawowych
i pozwoliły na wyjaśnienie wielu kwestii dotyczących aktywności biologicznej
i charakterystyki fizykochemicznej proponowanych fotouczulaczy. Jednocześnie
ujawniły nowe zagadnienia, które w przyszłości będą wymagały rozwiązania
i wyjaśnienia, wskazując dalsze kierunki badań. Ukończenie niniejszej pracy
z pewnością nie oznacza zakończenia prac nad możliwością zastosowania omawianych
fotouczulaczy w terapii fotodynamicznej, a jedynie otwiera nowy, kolejny etap badań
Emergence of a substrate-temperature-dependent dielectric process in a prototypical vapor deposited hole-transport glass
Since the discovery of ultrastability, vapor deposition has emerged as a relevant tool to further understand the nature of glasses. By this route, the density and average orientation of glasses can be tuned by selecting the proper deposition conditions. Dielectric spectroscopy, on the other hand, is a basic technique to study the properties of glasses at a molecular level, probing the dynamics of dipoles or charge carriers. Here, and for the first time, we explore the dielectric behavior of vapor deposited N,N-Diphenyl-N,N’bis(methylphenyl)-1,1′-biphenyl-4,4′-diamines (TPD), a prototypical hole-transport material, prepared at different deposition temperatures. We report the emergence of a new relaxation process which is not present in the ordinary glass. We associate this process to the Maxwell-Wagner polarization observed in heterogeneous systems, and induced by the enhanced mobility of charge carriers in the more ordered vapor deposited glasses. Furthermore, the associated activation energy establishes a clear distinction between two families of glasses, depending on the selected substratetemperature range. This finding positions dielectric spectroscopy as a unique tool to investigate the structural and electronic properties of charge transport materials and remarks the importance of controlling the deposition conditions, historically forgotten in the preparation of optoelectronic devices
Electrophoretic deposition of chitosan coatings on the Ti15Mo biomedical alloy from a citric acid solution
Chitosan biocoatings were successfully deposited on the Ti15Mo alloy surface via cataphoretic deposition from a solution of 1 g dm−3 of chitosan in 4% (aq) citric acid. The influence of the cataphoretic deposition parameters on quality and morphology of the obtained coatings were investigated using fluorescence and scanning electron microscopy. The functional groups' presence in chitosan chine were confirmed by ATR-FTIR methods. X-ray analysis revealed the amorphous structure of the chitosan coatings on the Ti15Mo alloy surface. The conducted studies also include assessing the abrasion resistance and adhesion to the substrate of the obtained chitosan coatings. The results show that utilizing the citric acid as a solvent results in the formation of pore free coatings. The yield of the electrophoretic deposition process was in the range of 2–10 mg of deposited chitosan per 1 cm2. The obtained coatings through the unique properties of chitosan are a promising biomaterial for application in medicine
Distinguishing different classes of secondary relaxations from vapour deposited ultrastable glasses
Secondary relaxations persistent in the glassy state after structural arrest are especially relevant for the
properties of the glass. A major thrust in research in dynamics of glass-forming liquids is to identify what
secondary relaxations exhibit a connection to the structural relaxation and are hence more relevant. Via
the Coupling Model, secondary relaxations having such connection have been identified by properties
similar to the primitive relaxation of the Coupling Model and are called the Johari–Goldstein (JG)
b-relaxations. They involve the motion of the entire molecule and act as the precursor of the structural
a-relaxation. The change in dynamics of the secondary relaxation by aging an ordinary glass is one way
to understand the connection between the two relaxations, but the results are often equivocal.
Ultrastable glasses, formed by physical vapour deposition, exhibit density and enthalpy levels comparable
to ordinary glasses aged for thousands of years, as well as some particular molecular arrangement. Thus,
ultrastable glasses enable the monitoring of the evolution of secondary processes in case aging does
not provide any definitive information. Here, we study the secondary relaxation of several ultrastable
glasses to identify different types of secondary relaxations from their different relationship with the
structural relaxation. We show the existence of two clearly differentiated groups of relaxations: those
becoming slower in the ultrastable state and those becoming faster, with respect to the ordinary unaged
glass. We propose ultrastability as a way to distinguish between secondary processes arising from the
particular microstructure of the system and those connected in properties to and acting as the
precursor of the structural relaxation in the sense of the Coupling Model
New limits of secondary β-relaxation
Glass is an ultraviscous liquid that ceases to flow on a laboratory timescale but continues to relax on a geological timescale. Quintessentially, it has become hopeless for humans to explore the equilibrium behavior of glass, although the technology of glass making witness a remarkable advance. In this work, we propose a novel thermodynamic path to prepare a high density amorphous state of matter (carvedilol dihydrogen phosphate) using high pressure. In addition, we provide the impeccable experimental evidence of heterogeneous nature of secondary β-relaxation and probe its properties to understand the various aspects of pressure densified glass, such as dynamics, packing and disorder. These features are expected to provide new horizons to glass preparation and functional response to pharmaceutical applications
Design, synthesis and in Vitro activity of anticancer styrylquinolines. The p53 Independent Mechanism of Action
A group of styrylquinolines were synthesized and tested for their anti-proliferative activity.
Anti-proliferative activity was evaluated against the human colon carcinoma cell lines that
had a normal expression of the p53 protein (HCT116 p53+/+) and mutants with a disabled
TP53 gene (HCT116 p53-/-) and against the GM 07492 normal human fibroblast cell line. A
SAR study revealed the importance of Cl and OH as substituents in the styryl moiety. Several
of the compounds that were tested were found to have a marked anti-proliferative activity
that was similar to or better than doxorubicin and were more active against the p53 null
than the wild type cells. The cellular localization tests and caspase activity assays suggest
a mechanism of action through the mitochondrial pathway of apoptosis in a p53-independent
manner. The activity of the styrylquinoline compounds may be associated with their
DNA intercalating ability
Secondary relaxation in ultrastable etoricoxib : evidence of correlation with structural relaxation
Secondary relaxations are fundamental for their impact in the properties of glasses and for their
inseparable connection to the structural relaxation. Understanding their density dependence and aging
behavior is key to fully address the nature of glasses. Ultrastable glasses establish a new benchmark to
study the characteristics of secondary relaxations, since their enthalpy and density levels are unattainable
by other routes. Here, we use dielectric spectroscopy at ambient and elevated pressures to study the
characteristics of the secondary relaxation in ultrastable etoricoxib, reporting a 71% decrease in dielectric
strength and one decade increase in relaxation time compared to the ordinary glass. Interestingly, we
find an unprecedented connection between secondary and structural relaxations in ultrastable etoricoxib
in exactly the same manner as in the ordinary glass, manifested through different properties, such as
aging and devitrification. These results further support and extend the general validity of the connection
between the secondary and structural relaxation
Complex reorientation dynamics of sizable glass-formers with polar rotors revealed by dielectric spectroscopy
We present the results of dielectric measurements for three sizable glass-formers
with identical nonpolar cores linked to various dipole-labeled rotors that shed new light on the
picture of reorientation of anisotropic systems with significant moment of inertia revealed by
broadband dielectric spectroscopy. The dynamics of sizable glass-formers formed by partially
rigid molecular cores linked to small polar rotors in many respects differs from that of typical
glass-formers. For instance, the extraordinarily large prefactors (τ0 > 10−12 s) in the Vogel−
Fulcher−Tammann equation were found. The rich and highly diverse relaxation pattern was
governed by the location of a dipole, its ability to rotate freely, and the degree of coupling to the
motion of the entire sizable system
Experimental evidence of high pressure decoupling between charge transport and structural dynamics in a protic ionic glass-former
In this paper the relaxation dynamics of ionic glass-former acebutolol hydrochloride (ACB-HCl) is studied as a function of temperature and pressure by using dynamic light scattering and broadband dielectric spectroscopy. These unique experimental data provide the first direct evidence that the decoupling between the charge transport and structural relaxation exists in proton conductors over a wide T-P thermodynamic space, with the time scale of structural relaxation being constant at the liquid-glass transition (τα = 1000 s). We demonstrate that the enhanced proton transport, being a combination of intermolecular H+ hopping between cation and anion as well as tautomerization process within amide moiety of ACB molecule, results in a breakdown of the Stokes-Einstein relation at ambient and elevated pressure with the fractional exponent k being pressure dependent. The dT g /dP coefficient, stretching exponent βKWW and dynamic modulus E a /ΔV # were found to be the same regardless of the relaxation processes studied. This is in contrast to the apparent activation volume parameter that is different when charge transport and structural dynamics are considered. These experimental results together with theoretical considerations create new ideas to design efficient proton conductors for potential electrochemical applications
Synthesis of New Styrylquinoline Cellular Dyes, Fluorescent Properties, Cellular Localization and Cytotoxic Behavior
New styrylquinoline derivatives with their photophysical constants are described. The synthesis was achieved via Sonogashira coupling using the newly developed heterogeneous nano-Pd/Cu catalyst system, which provides an efficient synthesis of high purity products. The compounds were tested in preliminary fluorescent microscopy studies to in order to identify their preferable cellular localization, which appeared to be in the lipid cellular organelles. The spectroscopic properties of the compounds were measured and theoretical TD- DFT calculations were performed. A biological analysis of the quinolines that were tested consisted of cytotoxicity assays against normal human fibroblasts and colon adenocarcinoma cells. All of the compounds that were studied appeared to be safe and indifferent to cells in a high concentration range. The presented results suggest that the quinoline compounds that were investigated in this study may be valuable structures for development as fluorescent dyes that could have biological applications
- …