Low-temperature zircon growth related to hydrothermal alteration of siderite concretions in Mississippian shales, Scotland

Zircon occurs in voids and cracks in phosphatic coprolites enclosed in siderite concretions in Mississippian shales near Edinburgh, Scotland. The zircon formed during hydrothermal alteration of early-diagenetic concretions and occurs as spherical aggregates of prismatic crystals, sometimes radiating. Vitrinite reflectance measurements indicate temperatures of ~270°C for the zircon-bearing concretions and the host shales. Molecular parameter values based on dibenzothiophene and phenanthrene distribution and occurrence of di- and tetra-hydro-products of polycyclic aromatic compounds suggest that the rocks experienced relatively high-temperature aqueous conditions related to hydrothermal fluids, perhaps associated with neighboring mafic intrusions. The zircon was dissolved from the concretions, transported in fluids, and reprecipitated in voids. This is the first record of the precipitation of authigenic zircon in sedimentary rock as a new phase, not as outgrowths

Tuneable helices of plasmonic nanoparticles using liquid crystal templates: molecular dynamics investigation of an unusual odd–even effect in liquid crystalline dimers

Liquid crystalline (LC) dimers formed helical nanofilaments depending on the parity of the alkyl linker, revealing an unusual odd–even effect. Molecular dynamics simulations were used to investigate the observed tendency. Elongation of the linker translates to an increase of the pitch of the helices, which allows achieving tuneable helical assemblies of Au nanoparticles doped to the LC matrix. The impact of the tuneable pitch of helices on the chiral optical properties of composites was investigated with full-wave simulations based on the T-matrix method

Combined anticancer therapy with imidazoacridinone analogue C-1305 and paclitaxel in human lung and colon cancer xenografts : modulation of tumour angiogenesis

The acridanone derivative 5-dimethylaminopropylamino-8-hydroxytriazoloacridinone (C-1305) has been described as a potent inhibitor of cancer cell growth. Its mechanism of action in in vitro conditions was attributed, among others, to its ability to bind and stabilize the microtubule network and subsequently exhibit its tumour-suppressive effects in synergy with paclitaxel (PTX). Therefore, the objective of the present study was to analyse the effects of the combined treatment of C-1305 and PTX in vivo. In addition, considering the results of previous genomic analyses, particular attention was given to the effects of this treatment on tumour angiogenesis. Treatment with C-1305 revealed antitumor effect in A549 lung cancer cells, and combined treatment with PTX showed tendency to anticancer activity in HCT116 colon cancer xenografts. It also improved tumour blood perfusion in both tumour models. The plasma level of CCL2 was increased and that of PDGF was decreased after combined treatment with C-1305 and PTX. The experimental results showed that the levels of FGF1, TGF-beta and Ang-4 decreased, whereas the levels of ERK1/2 and Akt phosphorylation increased in HCT116 tumour tissue following combined treatment with both drugs. The results of in vitro capillary-like structure formation assay demonstrated the inhibiting effect of C-1305 on this process. Although previous in vitro and in vivo studies suggested a positive effect of C-1305 on cancer cells, combined treatment of HCT116 human colon and A549 lung cancer cells with both PTX and C-1305 in vivo showed that the antitumor activity was restricted and associated with the modulation of tumour angiogenesis

A mild and efficient approach to the 6H-oxazolo[3,2-f]pyrimidine-5,7-dione scaffold via unexpected rearrangement of 2,3-dihydropyrimido[6,1-b][1,5,3]dioxazepine-7,9(5H,8H)-diones:synthesis, crystallographic studies, and cytotoxic activity screening

We report a mild and efficient approach to the optically pure 6H-oxazolo[3,2-f]pyrimidine-5,7-dione scaffold via the unexpected rearrangement and ring contraction of 2,3-dihydropyrimido[6,1-b][1,5,3]- dioxazepine-7,9(5H,8H)-diones derived from nucleoside precursors. The developed procedure enables the synthesis of a wide range of compounds with great structural diversity. The structure of the obtained compounds was confirmed by NMR spectroscopy and single crystal X-ray structural analysis. The final products were tested for cytotoxic effect on one non-cancerous (fibroblasts) and six cancer cell lines of different origins (colon, glioma, breast, cervix, vulvar, and lung). The synthesized products are low molecular weight compounds with lead-like properties suitable for a medicinal chemistry optimization program

Low-temperature zircon growth related to hydrothermal alteration of siderite concretions in Mississippian shales, Scotland

Zircon occurs in voids and cracks in phosphatic coprolites enclosed in siderite concretions in Mississippian shales near Edinburgh, Scotland. The zircon formed during hydrothermal alteration of early-diagenetic concretions and occurs as spherical aggregates of prismatic crystals, sometimes radiating. Vitrinite reflectance measurements indicate temperatures of ~270°C for the zircon-bearing concretions and the host shales. Molecular parameter values based on dibenzothiophene and phenanthrene distribution and occurrence of di- and tetra-hydro-products of polycyclic aromatic compounds suggest that the rocks experienced relatively high-temperature aqueous conditions related to hydrothermal fluids, perhaps associated with neighboring mafic intrusions. The zircon was dissolved from the concretions, transported in fluids, and reprecipitated in voids. This is the first record of the precipitation of authigenic zircon in sedimentary rock as a new phase, not as outgrowths

Fluid simulation using smooth particle hydrodynamics

Wygładzona hydrodynamika cząstek (eng.: Smooth Particle Hydrodynamics, dalej nazywane SPH) jest metodą numeryczną służącą do badania zachowania płynów. Chociaż pierwotnie została opracowana do prowadzenia badań w dziedzinie astrofizyki w 1977 przez R.A. Gingolda i J.J. Monaghana, została również łatwo zaadoptowana w hydrodynamice. Praca ta oparta jest głównie na publikacji M. Müllera, D. Charypara oraz M. Grossa z 2003 roku. Równania SPH rozwiązywane są za pomocą metody Lagrange’a. Są one szczególnym przypadkiem równań Naviera-Stokesa. Oprócz podstawowych sił obecnych w równaniach, zaimplementowano również dodatkowo siły napięcia powierzchniowego. Sama aplikacja tworzona jest w oparciu o środowisko Windows, a do kompilacji używany jest Visual Studio 2008. Do renderowania płynu używany jest OpenGL.Smooth particle hydrodynamics (later called SPH) is a numerical method used to study the behavior of fluids. Although it was originally developed for research in astrophysics in 1977 by RA Gingold and JJ Monaghan, it was also easily adapted for hydrodynamics. This work is mainly based on publication written by M. Müller, D. and M. Gross Charypara in 2003. SPH equations are solved by the Lagrange method equations which are a special case of the Navier-Stokes equations. Apart from the basic forces present in the equations, i have also included additional surface tension forces. The application itself is created in the Windows OS environment, built using Visual Studio 2008. For fluid rendering OpenGL is used

Active Plasmonics with Responsive, Binary Assemblies of Gold Nanorods and Nanospheres

Self-assembly of metal nanoparticles has applications in the fabrication of optically active materials. Here, we introduce a facile strategy for the fabrication of films of binary nanoparticle assemblies. Dynamic control over the configuration of gold nanorods and nanospheres is achieved via the melting of bound and unbound fractions of liquid-crystal-like nanoparticle ligands. This approach provides a route for the preparation of hierarchical nanoparticle superstructures with applications in reversibly switchable, visible-range plasmonic technologies

Electromagnetic angular positioner based on DC micromotor

The presented works concerned launching of an angular positioner powered by an electromagnetic actuator, designed for performing angular micromovements within a range of few microradians. The principle of operation is based on balancing the electromagnetic torque of the motor with a torque that is twisting a compliant element. As electrodynamic actuators have no distinguished controlled positions, therefore in typical positioning systems desired positions are obtained applying a closed-loop position control. Usually, such systems employ also a feedback (dumping) related to velocity of the moving elements, what simplifies forming of dynamics of the system. The design of the physical model employs a DC micromotor, whose rotor is coupled with a torsional torquemeter. A feedback signal is generated by resistive strain gauges. The paper presents a mathematical model of the positioning system, results of simulation study as well as results of experimental study. The simulation study indicates that it is possible to select such design features and such type of the micoromotor that a high dynamics of positioning is ensured

Constrained nucleoside analogues – crystal and molecular structure of 6,5’ - O-anhydrouridines fixed in the anti conformation.

A series of analogues of anhydrouridine have been synthesized and their crystal structures established using X-ray diffraction. For all cases, the ribose ring has O(4')-exo, C(4')-endo pucker and the pyrimidine base is in the anti conformation. Investigated compounds crystallise in different crystal systems (monoclinic, orthorhombic), have different space group symmetry (P21, P212121) and exhibit different intermolecular interactions (halogen and hydrogen bonds) among molecules in their crystal lattices. Moreover, in the case of the 5-benzyl-6,5'-O-anhydrouridine a significant positional disorder is present with the phenyl rings existing in two orientations