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Background Many aspects are currently being investigated, with the aim of improving the application of PDT in the clinic by rendering it more effective. One of the current trends focuses on the use of nanocarriers. The aim of this study is to describe novel photosensitizers among polyol amide chlorin e6 derivatives for photodynamic therapy (PDT) using liposomes. Methods In addition to their intracellular localization and antiproliferative activity against HCT116 cells, appropriate photophysical features have been determined (especially high 1O2 quantum yield production). Results and conclusions Fluorescent microscopy demonstrated that the compounds entered the endoplasmic reticulum (ER), lysosomes, mitochondria and partially the cytoplasm. All of the chlorins showed no dark cytotoxicity; however, high phototoxicity was observed. Using optical and electron microscopy, we investigated the impact of chlorin-based PDT upon cell damage leading to cell death. Chl ara 3 was identified as the most promising compound among polyol amide chlorin e6 derivatives and improved phototoxicity was observed as compared with a clinically approved temoporfin. Our results indicate that newly-synthesized chlorins seem to be promising candidates for PDT application, and two of them (chl ara 3 and chl mme 2) may create promising new drugs, both in the form of a free compound and as a liposomal formulation.

In order to accommodate an increasing demand for glassy carbon products with tailored characteristics, one has to understand the origin of their structure-related properties. In this work, through the use of high-resolution transmission electron microscopy, Raman spectroscopy, and electron energy loss spectroscopy it has been demonstrated that the structure of glassy carbon at different stages of the carbonization process resembles the curvature observed in fragments of nanotubes, fullerenes, or nanoonions. The measured nanoindentation hardness and reduced Young’s modulus change as a function of the pyrolysis temperature from the range of 600–2500 °C and reach maximum values for carbon pyrolyzed at around 1000 °C. Essentially, the highest values of the mechanical parameters for glassy carbon manufactured at that temperature can be related to the greatest amount of non-planar sp 2 -hybridized carbon atoms involved in the formation of curved graphene-like layers. Such complex labyrinth-like structure with sp 2 -type bonding would be rigid and hard to break that explains the glassy carbon high strength and hardness.

Granulocyte colony‐stimulating factor (G‐CSF) is used in clinical practice to mobilize cells from the bone marrow to the blood; however, it is not always effective. We show that cobalt protoporphyrin IX (CoPP) increases plasma concentrations of G‐CSF, IL‐6, and MCP‐1 in mice, triggering the mobilization of granulocytes and hematopoietic stem and progenitor cells (HSPC). Compared with recombinant G‐CSF, CoPP mobilizes higher number of HSPC and mature granulocytes. In contrast to G‐CSF, CoPP does not increase the number of circulating T cells. Transplantation of CoPP‐mobilized peripheral blood mononuclear cells (PBMC) results in higher chimerism and faster hematopoietic reconstitution than transplantation of PBMC mobilized by G‐CSF. Although CoPP is used to activate Nrf2/HO‐1 axis, the observed effects are Nrf2/HO‐1 independent. Concluding, CoPP increases expression of mobilization‐related cytokines and has superior mobilizing efficiency compared with recombinant G‐CSF. This observation could lead to the development of new strategies for the treatment of neutropenia and HSPC transplantation., Recombinant G‐CSF is the mobilizing factor used for treating neutropenia and prior to harvesting hematopoietic stem cells for transplantation. This article describes cobalt protoporphyrin IX as a new efficient mobilizing factor upstream of G‐CSF.

Six monophenyltripyridylporphyrin derivatives were synthesized and characterized by spectroscopy in order to demonstrate their potential usefulness as photosensitizers for anticancer therapy purposes. Compounds 1 and 3–5 are amphiphilic, thus they may be suitable for transfer inside cells. Photochemical parameters such as fluorescence yield and singlet oxygen yield were determined. The former parameter does not exceed 10% which makes them unsuitable for photodynamic diagnosis (PDD). However, singlet oxygen yields are high and sufficient for these compounds to be considered as potential photodynamic therapy (PDT) photosensitizers.

Two platinum(II) coordination compounds, [PtCl(4′-R1-terpy)](SO3CF3) (1) and [PtCl(4′-R2-terpy)](SO3CF3) (2), with 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine (4′-R1-terpy) or 4′-(3-pyridyl)-2,2′:6′,2″-terpyridine (4′-R2-terpy) were synthesized and the impact of the pendant pyridyl ring on the structure and cytotoxic activity of Pt(II)-terpyridine complexes was explored. The single-crystal X-ray diffraction analysis confirmed square planar coordination of the cations [PtCl(4′-Rn-terpy)]+. The mode of binding of 1 and 2 to calf thymus DNA was examined by UV–Vis absorption titration, ethidium displacement assay and reaction with 9-ethylguanine, and the mixed covalent-intercalative mode was demonstrated. The cytotoxicity of the Pt(II) complexes against six cancer cell lines and three normal ones was determined using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and compared to cisplatin. The IC50 values for the compound 2 towards the cancer cell lines are in the low micromolar range. Most remarkably, 2 was over 4 times more effective than 1 and cisplatin against non-small lung adenocarcinoma (A549), and its selectivity index was ~60–80 times higher than that for 1 and cisplatin. The mechanisms underlying the loss of viability under treatment of 2 was further investigated including F-actin staining, mitotic index analysis, cytometric cell cycle analysis, Fluorescein isothiocyanate (FITC) -conjugated Annexin V antibody and propidium iodide (PI) staining, measurements of reactive oxygen species (ROS) in cells, analysis of changes in the mitochondrial mass and potential and quantitative real time polymerase chain reaction (qRT-PCR) genes analysis. The compound 2 was found to have a pro-oxidative effect by strong stimulation of cells for the production of reactive oxygen species and cytostatic effect through cell cycle arrest.

This research evaluated the suitability of synthetic photosensitizers for their use as potential photosensitizers in photodynamic therapy using steady state and time-resolved spectroscopic techniques. Four tetraphenylporphyrin derivatives were studied in ethanol and dimethyl sulfoxide. The spectroscopic properties namely electronic absorption and emission spectra, ability to generate singlet oxygen, lifetimes of the triplet state, as well as their fluorescence quantum yield were determined. Also time-correlated single photon counting method was used to precisely determine fluorescence lifetimes for all four compounds. Tested compounds exhibit high generation of singlet oxygen, low generation of fluorescence and they are chemical stable during irradiation. The studies show that the tested porphyrins satisfy the conditions of a potential drug in terms of physicochemical properties.

In non-invasive anticancer photodynamic therapy (PDT), a nontoxic photosensitizer (PS), which is activated by visible light, is used as a magic bullet that selectively destroys cancer cells. Recently, we described the combined therapy of 5-aminolevulinic acid (ALA-PDT) with thiosemicarbazone (TSC), i.e. an iron-chelating agent. This resulted in a strong synergistic effect. Herein, we investigated a novel strategy using a combination of PDT consist of the xenobiotic-porphyrin type PS with TSC. We observed a synergistic effect for all of the pairs of TSC-PS. This approach can be rationalized by the fact that both chlorin and TSC can affect the generation of reactive oxygen species (ROS). In order to elucidate the plausible mechanism of action, we also combined the investigated PSs with DFO, which forms complexes that are redox inactive. We detected a slight antagonism or additivity for this combination. This may suggest that the ability of an iron chelator (IC) to participate in the production of ROS and the generation of oxidative stress is important.

Powder composed of copper oxides nanoparticles with various capping agents has been synthesized and characterized with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol (PVA), glycol propylene, glycerin and glycerin plus ammonia were used as capping agents. The scanning electron microscopy (SEM) studies showed that nanoparticles form agglomerates with the size from 80 to 120 nm while particles size determined from the XRD experiment was in the range from 7 to 21 nm. XPS and XRD experiments revealed that depending on capping and reducing agents used in the synthesis nanoparticles are composed of Cu2O, CuO or a mixture of them. The biological activity test performed for a selected sample where the capping agent was glycerin plus ammonia has shown promising killing/inhibiting behavior, very effective especially for Gram negatives bacteria.

Two series of thiosemicarbazone-based iron chelators (twenty-seven compounds) were designed and synthesized using a microwave-assisted approach. Quinoline and halogenated phenyl were selected as parent scaffolds on the basis of a similarity search. The lipophilicity of the synthesized compounds was measured using HPLC and then calculated. Primary in vitro screening of the synthesized compounds was performed against eight pathogenic fungal strains. Only a few compounds showed moderate activity against fungi, and (E)-2-(quinolin-2-ylvinyl)-N,N-dimethylhydrazine-carbothioamide appeared to be more effective than fluconazole against most of the fungal strains tested. Antiproliferative activity was measured using a human colon cancer cell line (HCT-116). Several of the tested compounds showed submicromolar antiproliferative activity. Compounds were also tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The structure-activity relationships are discussed for all of the compounds.

Collagen fibrils type I display a typical banding pattern, so-called D-periodicity, of about 67 nm, when visualized by atomic force or electron microscopy imaging. Herein we report on a significant shortening of the D-period for human corneal collagen fibrils type I (21 ± 4 nm) upon air-drying, whereas no changes in the D-period were observed for human scleral collagen fibrils type I (64 ± 4 nm) measured under the same experimental conditions as the cornea. It was also found that for the corneal stroma fixed with glutaraldehyde and air-dried, the collagen fibrils show the commonly accepted D-period of 61 ± 8 nm. We used the atomic force microscopy method to image collagen fibrils type I present in the middle layers of human cornea and sclera. The water content in the cornea and sclera samples was varying in the range of .066-.085. Calculations of the D-period using the theoretical model of the fibril and the FFT approach allowed to reveal the possible molecular mechanism of the D-period shortening in the corneal collagen fibrils upon drying. It was found that both the decrease in the shift and the simultaneous reduction in the distance between tropocollagen molecules can be responsible for the experimentally observed effect. We also hypothesize that collagen type V, which co-assembles with collagen type I into heterotypic fibrils in cornea, could be involved in the observed shortening of the corneal D-period.

Engineered nanomaterials, especially metallic nanoparticles, are the most popular system applied in daily life products. The study of their biological and toxicity properties seems to be indispensable. In this paper, we present results of biological activity of Ag/Cu nanoparticles. These nanoparticles show more promising killing/inhibiting properties on Gram-negative bacteria than for Gram-positive ones. The Gram-negative bacteria show strong effect already at the concentration of 1 ppm after 15 min of incubation. Moreover, in vitro tests of toxicity made on normal human dermal fibroblast cultures showed that after 72 h of incubation with Ag/Cu nanoparticles, they are less toxic then Cu2O/CuO nanoparticles.

Profile analysis of powder diffraction lines was used to determine the changes of the lattice parameters versus temperature in perovskite SrTiO3 doped by W6+, Ni3+, Fe3+ and La3+ cations. The experiments were conducted in the temperature range from 12 K up to 300 K using the X-ray diffraction method. The temperatures of the structural phase transitions (SPT) as well as the type of distortion were determined from the splitting of some cubic lines such as (200), (220), (330), (400), (420). Our experiments revealed a small distortion from the cubic to the tetragonal symmetry. From our studies it also resulted that the tilting of oxygen octahedra is the main mechanism responsible for the SPT. The scheme of these transitions (according to Glazer's notation) may be written as follows: . For this model the crystal structure at low and high temperature symmetry was determined with the use of the Rietveld profile method.

The molecular structure of the 5,10,15,20-tetra(1-naphthyl)porphyrin and 5,10-di(4-hexadecyloxyphenyl)-15,20-di(4-pyridyl)porphyrin were studied using high-energy X-ray diffraction (ID15-B beam line) at ESRF, Grenoble, France. The energy of the incident photons was 90.45 keV. Two-dimensional detector was used. The intensity data were converted to the pair correlation function via the Fourier transform. The theoretical pair correlation functions were simulated using the density functional theory and compared with the experimental data. Obtained results indicate that the used experimental technique together with the applied interpretation method can be regarded as efficient tools for the determination of the atomic arrangement in molecules of such kind.

The aim of this article is to examine the crystallization tendencies of three chemically related amorphous anti-inflammatory agents, etoricoxib, celecoxib, and rofecoxib. Since the molecular mobility is considered as one of the factors affecting the crystallization behavior of a given material, broadband dielectric spectroscopy was used to gain insight into the molecular dynamics of the selected active pharmaceutical ingredients. Interestingly, our experiments did not reveal any significant differences in their relaxation behavior either in the supercooled liquid or in the glassy state. Hence, as a possible explanation for the enhanced physical stability of etoricoxib, its ability to undergo a tautomerization reaction was recognized. The occurrence of intramolecular proton transfer in the disordered etoricoxib was proven experimentally by time-dependent dielectric and infrared (IR) measurements. Additionally, IR spectroscopy combined with density functional theory calculations pointed out that in the etoricoxib drug, being in fact a binary mixture of tautomers, the individual isomers may interact with each other through a hydrogen bonding network. A possible explanation of this issue was achieved by performing dielectric experiments at elevated pressure. Since compression results in etoricoxib recrystallization, the possible influence of pressure on the observed stabilization effect is also carefully discussed.

Cell parameter evolution versus temperature has been established for both V 2 O 5 and MoO 3 , from 15 to 953 and 893 K, respectively. Both oxides preserve their orthorhombic crystal system and their respective space groups Pmmn and Pnma in the whole temperature range. Unusual evolution of the unit cells have been detected in these oxides and proposals are made to follow them based on detailed structural analysis. Three temperature domains have been evidenced for V 2 O 5 marked by breaks at RT and 800 K; for MoO 3 , only two domains are defined below and above 400 K. For each domain the quality of cell parameters and X-ray powder pattern indexing, have been checked by mathematical functions to buttress their coherent evolution within each temperature domain.

Photodynamic therapy (PDT) and photodynamic diagnostics (PDD) of cancer are based on the use of non-toxic dyes (photosensitisers) in combination with harmless visible light. This paper reports physicochemical properties, cell uptake, localisation as well as photodynamic efficiency of two novel lipophilic porphyrin derivatives, suitable for use as PDT sensitisers. Both compounds are characterised by high quantum yield of singlet oxygen generation which was measured by time-resolved phosphorescence. Photodynamic in vitro studies were conducted on three cancer cell lines. Results of cell survival tests showed negligible dark cytotoxicity but high phototoxicity. The results also indicate that cell death is dependent on energy dose and time following light exposure. Using confocal laser scanning microscopy both compounds were found to localise in the cytoplasm around the nucleus of the tumour cells. The mode of cell death was evaluated based on the morphological changes after differential staining. In summary, good photostability, high quantum yield of singlet oxygen and biological effectiveness indicate that the examined lipophilic porphyrin derivatives offer quite interesting prospects of photodynamic therapy application.

The Pb(Mn1/3Nb2/3)O3 ceramics has been obtained from oxides by sintering in air, using a two-stage process with precursor columbite-like (Mn0.5Nb)O3 phase. The PbO oxide was added in the second stage. Analysis of the X-ray diffraction pattern shows that the ceramics consist of 91% of major perovskite phase. A monoclinic distortion of the perovskite structure was found. The cell parameters are a = 12.193(3) A, b = 11.966(6) A, c = 12.144(2) A, β = 90°10.7′. The microanalysis made with SEM exhibited fluctuation in chemical composition of the perovskite phase. Precipitation of MnO2, PbO and the Pb–Mn–Nb–O phase different from perovskite was found. The X-ray photoelectron spectroscopy was used to study the electronic structure of the Pb(Mn1/3Nb2/3)O3 ceramics. The core levels of lead, manganese, niobium and oxygen were measured. The shape of valence band ridge is influenced by Mn 3d states. The real average chemical composition obtained from the XPS measurement is Pb0.99(Mn0.42Nb0.67)O2.92. Broadband dielectric measurement was carried out in 10−2 to 106 Hz and within 80–700 K ranges. The dominant relaxation process exhibits characteristic times typical for ionic processes τ0,H = 1 × 10−11 s for the higher temperature range and, τ0,L = 1 × 10−9 s for lower temperatures. The activation energy of relaxation process, EM,H = 0.43 eV and EM,L = 0.34 eV corresponds to activation energy of electric conductivity. The dielectric relaxation is ascribed to dipoles created by oxygen vacancies and/or Mn–VO complexes.

Ferroelectric relaxor 0.91PbMg1/3Nb2/3O3?0.09PbTiO3 single crystals in a wide temperature range were studied using dielectric, x-ray powder diffraction and Raman scattering techniques. Dielectric studies show that without applying an external electric field, 0.91PMN?0.09PT exhibits typical relaxor behaviour with at 310?K (1?kHz), while after cooling in an electric field the transition from the relaxor state to the long-range ferroelectric one is observed at 270?K. X-ray powder diffraction reveals that 0.91PMN?0.09PT undergoes structural phase transition from cubic to rhombohedral symmetry (R3m) at Tc = 283?K. However, based on the results of Raman scattering, the existence of clusters with 1?:?1 order in the B-sublattice, leading to the doubling of the unit cell parameters, and the appearance of (Z = 2) space group symmetry above Tc, and R3m (Z = 2) below Tc were stated. These results indicate the special role played by the Pb ion dynamics. Correlated Pb ion displacements creating the polar nanoregions, and the temperature evolution of these nanoregions directly determine all physical properties of 0.91PMN?0.09PT. An overall view of the behaviour of this solid solution within a wide temperature range is presented.

New (Na 0.5 Pb 0.5 )(Nb 0.5 Mn 0.5 )O 3 ceramics have been obtained from oxides by sintering in air, using a two-step process with precursor phase. The ceramics showed a perovskite phase (98%) with symmetry identified as monoclinic space group P 2 1 / m . The cell parameters were: a = 11.195(2) A, b = 11.249(1) A, c = 11.303(2) A, β = 89.77(1) 0 , V = 1423.2(3) A 3 . XPS examination of the compound allowed it to estimate the average composition as (Na 0.90 Pb 0.55 )(Mn 0.32 Nb 0.53 )O 2.70 . The SEM analysis showed the real distribution of the atoms within the perovskite phase. Precipitates of lead, sodium and manganese oxides were found. The valence band consisted of O 2p states hybridized with Nb 4d states containing an admixture of Mn 3d and Pb 6p states. A mixed ionic and covalent character of the bonds was found from the chemical shift. The presence of oxygen vacancies was deduced from the electric conductivity, characterized by an activation energy equal to 0.37 and 0.48 eV.

The structural and vibrational properties of above mentioned crystals were determined using X-ray powder diffraction and Raman scattering experiments. At room temperature hydrate layered perovskites: Rb{sub 2}MnF{sub 5}{center_dot}H{sub 2}O and K{sub 2}FeF{sub 5}{center_dot}H{sub 2}O exhibit orthorhombic--Cmcm (D{sub 2h}{sup 17}) and monoclinic--C2/c (C{sub 2h}{sup 6}) symmetry. Their structure is built up of MnF{sub 6} or FeF{sub 5}{center_dot}H{sub 2}O octahedra forming trans-linked zig-zag chains or hydrogen bonded zig-zag chains along the major crystallographic direction [0 0 1], respectively. To confirm crystal structures and to describe lattice dynamics of these compounds the vibrational normal modes (in {gamma} point of first Brillouin zone) were calculated on the base of the group theory analysis and compared with the spectra obtained from Raman scattering experiments. A relatively good reliability was obtained for both X-ray powder diffraction and Raman scattering.

The structures and phase transitions of AgNbO3 were investigated using neutron powder diffraction and restricted single-crystal x-ray diffraction. Both methods have revealed the high temperature M3–O1, O2–T and T–C phase transitions but have not given any significant evidence of low temperature M1–M2 and M2–M3 ones. The refinements of neutron diffraction patterns allowed us to determine the symmetry, space group and crystal structure for all phases except the O1 one. The existence of structural disorder in the T and probably O2 phases was found. The high temperature paraelectric phase transitions can be interpreted on the basis of consecutive condensation of oxygen octahedron tilts around the main axis. The ferroelectric and antiferroelectric behaviour has been associated with Ag and Nb cations. The reason why phase transitions between low temperature ferroelectric and antiferroelectric phases are not detectable by diffraction methods is discussed. The sequence of phase transitions in AgNbO3 can then be understood in the framework of a long range and/or local order–disorder type arrangement.

We describe our study of ballistic transport in nanostructures of lead telluride, PbTe. Submicron devices have been fabricated by electron beam lithography and chemical etching of 50 nm wide PbTe single quantum wells embedded between Pb 0.92 Eu 0.08 Te barriers grown by MBE on BaF 2 . The electron concentration in the devices was tuned by the gate voltage applied across an interfacial p–n junction. The most important observation was zero-magnetic field conductance quantization (in multiplies of 2 e 2 / h ) in narrow constrictions of dimensions comparable to electron mean free path calculated from transport mobility. This indicates considerable relaxation of requirements for quantum ballistic transport in comparison with other materials. We argue that the huge static dielectric constant of PbTe ( e 0 =1350 at 4.2 K ) leads to suppression of the long-range Coulomb potentials of charged impurities and, thus, provides favorable conditions for the conductance quantization.

The influence of substitution of Li+, Na+, Rb+ and Cs+ ions in the archetype KMnF3 perovskite crystal was studied by the Raman method. The Raman spectra of (K1-xAx)MnF3 mixed crystals (x≤0.15) were recorded in the range between 30 and 300 K and interpreted in terms of a `one-mode' behaviour. Attention was paid to evidence of the static and dynamical disorder. From this point of view the behaviour of hard Raman modes versus temperature has been studied together with two unexpected broad Raman bands in the normally inactive ideal cubic phase. The existence of these two broad peaks in the theoretically inactive cubic phase and also the persistence of the hard Raman modes of the tetragonal phase in cubic symmetry suggest the existence of a large structural disorder far above the cubic-to-tetragonal phase transition. The results of Raman investigations are discussed in the more general framework of structural disorder in perovskite systems.

Thiosemicarbazones (TSCs) are an interesting class of ligands that show a diverse range of biological activity, including anti-fungal, anti-viral and anti-cancer effects. Our previous studies have demonstrated the potent in vivo anti-tumor activity of novel TSCs and their ability to overcome resistance to clinically used chemotherapeutics. In the current study, 35 novel TSCs of 6 different classes were designed using a combination of retro-fragments that appear in other TSCs. Additionally, di-substitution at the terminal N4 atom, which was previously identified to be critical for potent anti-cancer activity, was preserved through the incorporation of an N4-based piperazine or morpholine ring. The anti-proliferative activity of the novel TSCs were examined in a variety of cancer and normal cell-types. In particular, compounds 1d and 3c demonstrated the greatest promise as anti-cancer agents with potent and selective anti-proliferative activity. Structure-activity relationship studies revealed that the chelators that utilized “soft” donor atoms, such as nitrogen and sulfur, resulted in potent anti-cancer activity. Indeed, the N,N,S donor atom set was crucial for the formation of redox active iron complexes that were able to mediate the oxidation of ascorbate. This further highlights the important role of reactive oxygen species generation in mediating potent anti-cancer activity. Significantly, this study identified the potent and selective anti-cancer activity of 1d and 3c that warrants further examination.

Practical applications of photosynthesis-inspired processes depend on a thorough understanding of the structures and physiochemical features of pigment molecules such as chlorophylls and bacteriochlorophylls. Consequently, the major structural features of these pigments have been systematically examined as to how they influence the S_{1} state energy, lifetimes, quantum yields, and pigment photostability. In particular, the effects of the macrocyclic π-electron system, central metal ion (CMI), peripheral substituents, and pigment aggregation, on these critical parameters are discussed. The results obtained confirm that the π-electron system of the chromophore has the greatest influence on the light energy conversion capacity of porphyrinoids. Its modifications lead to changes in molecular symmetry, which determine the energy levels of frontier orbitals and hence affect the S_{1} state properties. In the case of bacteriochlorophylls aggregation can also strongly decrease the S_{1} energy. The CMI may be considered as another influential structural feature which only moderately influences the ground-state properties of bacteriochlorophylls but strongly affects the singlet excited-state. An introduction of CMIs heavier than Mg^{2+} significantly improves pigments' photostabilities, however, at the expense of S_{1} state lifetime. Modifications of the peripheral substituents may also influence the S1 energy, and pigments’ redox potentials, which in turn influence their photostability.

In photodynamic therapy (PDT), a noninvasive anticancer treatment, visible light, is used as a magic bullet selectively destroying cancer cells by a photosensitizer that is nontoxic in the dark. Protoporphyrin IX (PpIX) is a natural photosensitizer synthesized in the cell, which is also a chelating agent that if bonded to Fe(2+) forms heme, a central component of hemoglobin. Therefore, xenobiotic iron chelators can disturb iron homeostasis, increasing the accumulation of PpIX, obstructing the last step of heme biosynthesis, and enhancing PDT efficiency. However, the attempts to use this promising idea have not proved to be hugely successful. Herein, we revisited this issue by analyzing the application of iron chelators highly toxic in the dark, which should have higher Fe(2+) affinity than the nontoxic chelators used so far. We have designed and prepared thiosemicarbazones (TSC) with the highest dark cellular cytotoxicity among TSCs ever reported. We demonstrate that compound 2 exerts powerful PDT enhancement when used in combination with 5-aminolevulinic acid (ALA), a precursor of PpIX.

A study of the influence of cationic Na+ substitution in the archetype KMnF3 perovskite crystal was performed using the Raman method. The Raman spectra of mixed K1-xNaxMnF3 crystals with x = 0.029, 0.048 and 0.065 were recorded versus temperature and fully interpreted in terms of a “one mode” behaviour. In addition to the soft mode not completely vanishing close to Tc, attention was especially paid to evidence of static and dynamical disorder. From this point of view the behaviour of the hard Raman modes versus temperature has been studied together with two unexpected Raman bands in the cubic phase. The interpretation has been made within the more general framework of structural disorder existing in such perovskites with anisotropic interactions.

The optical excitation and luminescence spectra of (Pr3+,Ce3+) ions in KCaF3 are presented. High-resolution excitation and emission spectra of Pr3+ and Ce3+ were measured at temperatures between 77 and 293 K. First measurements of KCaF3 : Ce3+ crystal show that there are nonequivalent Ce3+ centers which radiate either in UV or visible range. The major Ce3+ nonequivalent center in KCaF3 is Ce3+ ion in the site with tetragonal site symmetry (S4). Energy levels for the 4f2 ground configuration of Pr3+ in KCaF3 were established from excitation and fluorescence spectra. Energy levels assignments were made assuming electric-dipole transition selection rules for S4 site symmetry. Twenty-seven energy levels in the lowest six multiplets of the ground configuration were established. In the analysis of experimental data, the Oh magnetic-dipole selection rules were also considered to explain missing or weak transitions which are allowed in S4. Spectra of Pr3+ in KCaF3 have been analyzed with a crystal-field Hamiltonians of S4 or Oh symmetries including J mixing effects. Crystal-field parameters in these Hamiltonians have been determined by the minimization the RMS deviation between calculated and experimental energy Stark levels. We conclude that both model calculations in the S4 and Oh site symmetries for Pr3+ in KCaF3, provide the basis for a consistently good correlation with data.

It is known that the spectroscopic properties of 3d impurities in crystals are very sensitive to the environment of the ion and can be changed considerably by using different matrices. The crystal structure of KCaF3 has been previously determined by the Rietveld profile method. At room temperature, KCa1−xMnxF3 (x

A full investigation of structural instabilities in the mixed perovskite crystal Rb0.68K0.32CaF3 was performed by optical birefringence, X-ray diffraction and Raman scattering. A sequence for the phase transitions, according to the Glazer formalism, is proposed in agreement with that occurring in both the pure crystals RbCaF3 and KCaF3. Raman spectra are interpreted using group theory analysis and discussed in the framework of a classical Landau behaviour. With this work, the unusual phase transition mechanism observed for the perovskite KCaF3 appears accessible to experiment and is then studied in detail.

The structure of a series of activated carbon materials prepared from a polymer of phenol formaldehyde resin with different degree of “burn-off” from 0 to 32% and variable porosity has been studied by wide-angle neutron scattering. The intensity measurements, extended to Q values of 50 A−1 yielded the radial distribution functions with the real space resolution of about 0.12 A. The obtained results show that the structural features of the investigated materials are not affected by the activation process. All well-defined peaks of the radial distribution functions can be reproduced by the model consisting of the defective graphite-like layers with weak inter-layer correlations.

The cubic-to-tetragonal phase transition in the mixed perovskite K{sub 1{minus}x}Li{sub x}MnF{sub 3} (x < 0.036) was investigated by single-crystal X-ray diffraction. Results of the structure refinement at 298 and 145 K are discussed. They confirm the cubic symmetry, the space group Pm3m, of the room temperature phase with strongly anisotropic thermal vibration amplitudes of the F atoms, which were also observed in the parent KMnF{sub 3}. Substitutional lattice imperfections at the K{sup +} sites shift the ferrodistortive phase transition to higher temperature T{sub c1} = 191 K, compared to 186.5 K in KMnF{sub 3}. The structural changes in the tetragonal phase (I4/mcm) are characterized by the displacements of the F atoms from the positions they occupy above T{sub cl}. However, the Li{sup +} ion dopants do not affect the octahedral network, the MnF{sub 6} octahedra remain regular, and no displacements of K{sup +}/Li{sup +} cations along the tetragonal c axis are observed. The thermodynamic character of the transition is illustrated with the critical behavior of the unit cell parameters and the temperature-dependent evolution of the tetragonal deformation and the macroscopic strain. A variation of the integrated intensity of superstructure reflections close to T{sub cl} has been assumed to describe themore » behavior of the order parameter. As far as the precision of the present experiment allows, all these observations show that 3.6% Li{sup +} substitution at the K{sup +} site does not radically change the nature of the transition in KMnF{sub 3} at T{sub cl}.« less

Profile analysis of powder diffraction lines was used to determine the changes of the lattice parameters versus temperature in KMnF 3 doped by Li + , Na + and Rb + cations. The temperatures of the structural phase transitions (SPT), the type of distortion and the phase diagram in the concentration range x < 0.15 were determined from the splitting of some cubic lines as 211, 220 and 400. The discussion of the order of the SPT as a function of concentration is presented.

Spectral characteristics study of meso-tetraphenylporphyrin derivatives (TPP1 and TPP2) used as photosensitizers for utilization in photodynamic therapy (PDT) has been performed by density functional theory (DFT) and time dependent DFT (TD-DFT) calculations at B3LYP/6-31 G(d) level of theory using PCM solvation model. The geometrical parameters of porphyrins have been studied for ground and excited-state geometry to deduce the influence of various substituents as well as solvent effect on the deformation of porphyrin ring. Two theoretical approaches - linear response (LR) and external iteration (EI) - have been performed to replicate absorption and fluorescence emission spectra. Experimental and theoretical investigations have shown that EI method reproduces the absorption energies very well for both singlet-singlet and triplet-triplet transitions, whereas the LR approach is more coherent with experimental fluorescence emission spectra. Spectral features and HOMO-LUMO band gap analysis have shown that TPP1 can be more useful in PDT. Calculations have revealed that two the highest occupied and two the lowest unoccupied molecular orbitals are responsible for the Q-band absorption and are located mainly on the porphyrin ring. In order to verify the substituent effect on the activity of tested compounds in their ground and excited states, the molecular electrostatic potential surfaces have been analyzed.

Structural phase transitions have been found in the mixed fluoroperovskites crystals (Rb1−xKx)CaF3 (x=0.05, 0.2, 0.35, 0.5, 0.88, 1.0) by optical birefringence and X-ray diffraction. Profile analysis of powder diffraction lines was performed to determine the change of lattice parameters versus temperature in order to establish the crystal symmetry of each structural phase and to measure the temperatures of the transitions. From the splitting of the 400 cubic Bragg line and consideration of Glazer's classification of tilted octahedra in perovskites, the various types of distortions were found. Sequences of CaF6 tilting octahedra occurring during the phase transitions are suggested and discussed for each concentration.

Iron chelators have emerged as a potential anti-cancer treatment strategy. In this study, a series of novel thiosemicarbazone iron chelators containing a quinoline scaffold were synthesized and characterized. A number of analogs show markedly greater anti-cancer activity than the 'gold-standard' iron chelator, desferrioxamine. The anti-proliferative activity and iron chelation efficacy of several of these ligands (especially compound 1b), indicates that further investigation of this class of thiosemicarbazones is worthwhile.

We have studied the structural and magnetic properties of two compounds from the Me32+(Fe3+(CN)6-)23-.H2O family, where Me=Ni and Co. From x-ray analysis we find that the compounds crystallize in the face-centred cubic structure with the space group of F43m. Both the Fe and Me ions are coordinated octahedrally by six carbon atoms and six nitrogen atoms, respectively. The Fe ions are in a strong crystalline field, while the Me ions are in an intermediate field with cubic symmetry. From the magnetic studies a quantitative bulk ferromagnetic behaviour (a spontaneous magnetization and a hysteresis loop) has been established for both complex compounds. In addition, from the magnetization against temperature curves we obtained, for both compounds, the Curie as well as Curie-Weiss temperatures, the Curie constants and the effective moments in the paramagnetic state. From the assumed value of the spin for every cation we fitted the chi T=F(T) curves and from the field dependence of the magnetization we determined the high-field susceptibility. The magnetic properties of the compounds were analysed in the framework of the mean-field theory.

Unit-cell parameters of KMnF3 single crystals have been measured by X-ray diffraction under hydrostatic pressure up to 9.5 GPa in a diamond-anvil cell. A cubic/tetragonal structural phase transition has been observed at Pc = 3.1 GPa. The tetragonal phase was stable to the upper limit of the measured pressure range (P = 10.0 GPa) and a linear pressure dependence of the macroscopic spontaneous strain ϵs above Pc has been shown. The linear and volume compressibilities of both phases have been calculated.

X-ray diffraction measurements of the lattice parameters as a function of temperature are reported for the mixed compounds KMn1-xNixF3 and KMn1-xCoxF3 where x 0.10. From the splitting of the cubic 400 Bragg reflections the transition temperatures of the structural phase transitions were determined. In the KMn0.99Co0.01F3 and KMn0.97Ni0.03F3 crystals three structural phase transitions were established. It was concluded that higher admixture quantities lead to a change in phase transition character which appeared to be smeared over a temperature range.

Profile analysis of powder diffraction lines was used to determine the variations in lattice parameters as a function of temperature. Using this procedure, phase diagrams of (K1-xNax)MnF3 and (K1-xLix)MnF3 were obtained in the concentration range x

Ce modele propose par Kassan-Ogly & Naish [Acta Cryst. (1986), B42, 297-335] sert a decrire l'evolution de la structure cristalline du compose en fonction de la temperature. Dans ce type de cristaux ont lieu deux transformations de phase structurales: cubique→tetragonal (T 1 =186K) et tetragonal→orthorhombique (T 2 =91K)

A group of styrylazanaphthalenes and azanaphthalenediones were synthesized and tested for their anti-proliferative activity. Most of the compounds were obtained with the use of microwave-assisted synthesis. The lipophilicity of the compounds was measured by RP-HPLC and their anti-proliferative activity was assayed against the human SK-N-MC neuroepithelioma and HCT116 human colon carcinoma cell lines. Active compounds were also tested in clonogenity and comet assays. Several quinazolinone and styrylquinazoline analogues were found to have markedly greater anti-proliferative activity than desferoxamine and cis-platin.

Photosensitizers with desirable combinations of chemical, photophysical and biological properties are essential for improving the efficacy of photodynamic therapy (PDT) against various cancers. Chlorins seem to be promising candidates for photodynamic therapy (PDT) owing to their photophysical properties. This paper reports spectroscopic and biological properties of a novel synthetic chlorin derivative. Cytotoxicity, phototoxicity as well as subcellular localization of the novel derivative was studied using Lewis lung carcinoma cultured cells (LLC). In the examined concentration range no significant cytotoxic effects were found but high phototoxicity was observed. Confocal laser scanning microscopy demonstrated that the compound, upon entering cells, was localized in the perinuclear cytoplasm of LLC cells. Using fluorescent microscopy we investigated the impact of PDT based on the novel compound upon cytoskeleton and DNA structure of LLC cells. Our results indicate that liposomes are effective in transferring the chlorin photosensitizer into the studied cells, leading to their high photosensitization, whereas the non-carrier delivery mode (i.e., DMSO) is rather useless for such purposes.

The molecule of the title compound, C12H16N2O4, is centrosymmetric and the amide group is twisted relative to the benzene ring by 14.40 (13)°. The molecules are hydrogen bonded into a three-dimensional framework, with the hydroxy O atoms acting as acceptors in N—H...O hydrogen bonds and as donors in O—H...O=C interactions.

The computational results of the features observed in the room-temperature Q-band absorption spectrum of free-base chlorin (H2Ch) are presented. The vibrational structures of the first and second excited singlet states were calculated based on a harmonic approximation using density functional theory and its time dependent extension within the Franck-Condon and Herzberg-Teller approaches. The outcome allowed to identify the experimental bands and to assign them to the specific vibrational transitions. A very good agreement between the simulated and measured wavelengths and their relative intensities provided the opportunity to predict the origin of the S0 → S2 transition which could not be determined experimentally.

International audience; In this work a systematic comparison of DC electrical conductivity and IR optical properties of thin films of (RxR'1-xNiO3), where R' = Nd and R = Sm or Eu, is performed. Independently of the nature of R, it is confirmed that the metal-insulator transition temperature (T-MI) in RxR'1-xNiO3 as well as in RNiO3 is driven by the mean lattice distortion quantified by the tolerance factor of the perovskite. The internal chemical pressure decrease due to substitution of Nd by another rare earth element with smaller cationic radius gives rise to an increasing resistivity in the metallic state together with a decrease of the screening effect in the IR reflectance. We suggest this is due to a modification of the free electron properties at the Fermi level and of the Fermi surface proper-ties consistent with photoemission literature data. On the other hand, similar transmittance spectra for various systems are reported in the insulating state. A systematic temperature independent drop of the transmittance above 0.6 eV is found for each system whatever the value of T-MI

The crystal structure of Cr2[Ni(CN)4]3·10H2O has been determined on X-ray diffraction powder data by means of the Rietveld method. The starting model was based on the isomorphic, disordered structure of Mn3[Co(CN)6]2·12H2O. At room temperature the crystal is cubic, F4¯3m, a=10.097(6) Å, V=1029.4(5) Å3. The structure is disordered and contains 1.33 formula weights per unit cell. The Ni and Cr ions are coordinated by N and C atoms, respectively, forming octahedra linked by CN groups. The water molecules replace partly the chromium, carbon, and nitrogen positions in the crystal. The final R values are: Rwp=0.032 (Rexp=0.023), RB=0.088, and DW-Stat.=1.31 (DWexp=1.8).

Two water soluble porphyrins: meso-tetra-4-N-methylpyridyl-porphyrin iodide (P1) and 5,10-di-(4-acetamidophenyl)-15,20-di-(4-N-methylpyridyl) porphyrin (P2) were synthesised and evaluated in respect to their photochemical and photophysical properties as well as biological activity. Cytotoxic and phototoxic effects were evaluated in human malignant melanoma Me45 line using clonogenic assay, cytological study of micronuclei, apoptosis and necrosis frequency and inhibition of growth of megacolonies. Both porphyrins were characterised by high UV and low visible light absorptions. Dark toxicity measured on the basis of the clonogenic assay and inhibition of megacolony growth area indicated that P1 was non-toxic at concentrations up to 50 microg/ml (42.14 microM) and P2 at concentrations up to 20 microg/ml (16.86 microM). The photodynamic effect induced by red light above 630 nm indicated that both porphyrins were able to inhibit growth of melanoma megacolonies at non-toxic concentrations. Cytologic examination showed that the predominant mode of cell death was necrosis.

In the title compound, C48H38N4O8·C3H6O2, the porphyrin molecule is centrosymmetric. The propionic acid solvent molecule is disordered over two sets of sites with equal occupancy factors. The porphyrin central core is almost planar, with an r.m.s. deviation of the fitted atoms of 0.045 Å. The substituent benzene rings make dihedral angles of 70.37 (4) and 66.95 (4)° with respect to the porphyrin core plane. The crystal structure is stabilized by an interesting network of hydrogen bonds. Porphyrin molecules are connected by O—H...O hydrogen bonds creating ribbons running along the [101] direction. Weak C—H...O hydrogen bonds connect separate molecular ribbons in the [110] direction, creating (-111) layers. Intramolecular N—H...N hydrogen bonds also occur. The propionic acid molecules are connected by pairs of —H...O hydrogen bonds, creating dimers.

We report the synthesis, photochemical and photophysical properties and preliminary studies on biological effect of a new tritolylporphyrin dimer (T-D). Absorption and emission properties of T-D suggest its possible use in photodynamic therapy. T-D is capable of singlet oxygen production with 0.8 quantum yield. It also has a high photostability. The photodynamic properties of the dimer were examined following the growth of SKMEL 188 (human melanoma) cells irradiated with red light (cut off < 630 nm). The surviving fraction of the cells decreased about 3-fold (vs. non-irradiated cells) for an 81 J/cm dose. Our results suggest that tritolylporphyrine dimer T-D may be an interesting hydrophobic sensitizer for photodynamic therapy.