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X ray phase contrast

Christina N Banti, Constantina Papatriantafyllopoulou, Anastasios J Tasiopoulos, Sotiris K Hadjikakou
The non steroidal anti-inflammatory drugs (NSAID's)-silver(I) metallodrugs of aspirin (aspH), salicylic acid (salH2), naproxen (napH) acid or p-hydrobenzoic acid (pHbzaH) and the mitochondriotropic triphenylarsine (tpAs) with the formulae [Ag(asp)(tpAs)3] (1), [Ag(salH)(tpAs)3] (2), [Ag(nap)(tpAs)3] (3) and {[Ag(pHbza)(tpAs)3]∙(dmf)} (4) and [Ag(tpAs)3(NO3)] (5) have been synthesized and characterized by m.p., FT-IR, UV-vis and (1)H NMR, spectroscopic techniques and X-ray crystallography. The in vitro cytotoxic activity of 1-5 against human breast adenocarcinoma cancer cells: MCF-7 (positive to estrogen receptors (ERs)) and MDA-MB-231 (negative to estrogen receptors (ERs)) was evaluated...
November 10, 2017: European Journal of Medicinal Chemistry
Anthony R Bradley, Aude Echalier, Michael Fairhead, Claire Strain-Damerell, Paul Brennan, Alex N Bullock, Nicola A Burgess-Brown, Elisabeth P Carpenter, Opher Gileadi, Brian D Marsden, Wen Hwa Lee, Wyatt Yue, Chas Bountra, Frank von Delft
The ongoing explosion in genomics data has long since outpaced the capacity of conventional biochemical methodology to verify the large number of hypotheses that emerge from the analysis of such data. In contrast, it is still a gold-standard for early phenotypic validation towards small-molecule drug discovery to use probe molecules (or tool compounds), notwithstanding the difficulty and cost of generating them. Rational structure-based approaches to ligand discovery have long promised the efficiencies needed to close this divergence; in practice, however, this promise remains largely unfulfilled, for a host of well-rehearsed reasons and despite the huge technical advances spearheaded by the structural genomics initiatives of the noughties...
November 8, 2017: Essays in Biochemistry
Joydip De, Santosh Prasad Gupta, Indu Bala, Sandeep Kumar, Santanu Kumar Pal
Five novel columnar liquid crystalline compounds (4.1-4.5) consisting of a central anthraquinone core carrying four alkoxy chains (R = n-C6H13, n-C8H17, n-C10H21, n-C12H25, and 3,7-dimethyl octyl) with two diagonally opposite 1-ethynyl-4-pentylbenzene units were synthesized, and their phase transitions were investigated between changes in the molecular structure and their self-assembly into the columnar mesophases. Small and wide-angle X-ray scattering (SAXS/WAXS) studies were performed to deduce the exact nature of the mesophases, and their corresponding electron density maps were derived from the intensities of the peaks observed in the diffraction patterns...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Nasima Kanwal, Delia S Brauer, Jonathan Earl, Rory M Wilson, Natalia Karpukhina, Robert G Hill
OBJECTIVES: The in-vitro dissolution of bioactive glass-based toothpastes and their capacity to form apatite-like phases in buffer solutions have been investigated. MATERIALS AND METHODS: The commercial toothpaste samples were tested on immersion in artificial saliva, Earle's solution and Tris buffer for duration from 10minutes to four days. The powder samples collected at the end of the immersion were studied using solid-state (31)P and (19)F nuclear magnetic resonance spectroscopy (NMR), X-ray powder diffraction and Fourier transform infrared (FTIR) spectroscopy...
October 30, 2017: Journal of Dentistry
Rachel Roccanova, Wenmei Ming, Vincent R Whiteside, Michael A McGuire, Ian R Sellers, Mao-Hua Du, Bayrammurad Saparov
We report the synthesis, crystal and electronic structures, as well as optical properties of the hybrid organic-inorganic compounds MA2CdX4 (MA = CH3NH3; X = Cl, Br, I). MA2CdI4 is a new compound, whereas, for MA2CdCl4 and MA2CdBr4, structural investigations have already been conducted but electronic structures and optical properties are reported here for the first time. Single crystals were grown through slow evaporation of MA2CdX4 solutions with optimized conditions yielding mm-sized colorless (X = Cl, Br) and pale yellow (X = I) crystals...
November 2, 2017: Inorganic Chemistry
Thomas Gaumnitz, Arohi Jain, Yoann Pertot, Martin Huppert, Inga Jordan, Fernando Ardana-Lamas, Hans Jakob Wörner
Attosecond metrology has so far largely remained limited to titanium:sapphire lasers combined with an active stabilization of the carrier-envelope phase (CEP). These sources limit the achievable photon energy to ∼100 eV which is too low to access X-ray absorption edges of most second- and third-row elements which are central to chemistry, biology and material science. Therefore, intense efforts are underway to extend attosecond metrology to the soft-X-ray (SXR) domain using mid-infrared (mid-IR) drivers. Here, we introduce and experimentally demonstrate a method that solves the long-standing problem of the complete temporal characterization of ultra-broadband (≫10 eV) attosecond pulses...
October 30, 2017: Optics Express
E Nazaretski, H Yan, K Lauer, N Bouet, X Huang, W Xu, J Zhou, D Shu, Y Hwu, Y S Chu
A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ∼15 nm × 15 nm spatial resolution using multilayer Laue lenses and 25 nm × 26 nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques...
November 1, 2017: Journal of Synchrotron Radiation
J Kuva, J Sammaljärvi, J Parkkonen, M Siitari-Kauppi, M Lehtonen, T Turpeinen, J Timonen, M Voutilainen
We set out to study connected porosity of crystalline rock using X-ray microtomography and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) with caesium chloride as a contrast agent. Caesium is an important radionuclide regarding the final deposition of nuclear waste and also forms dense phases that can be readily distinguished by X-ray microtomography and SEM-EDS. Six samples from two sites, Olkiluoto (Finland) and Grimsel (Switzerland), where transport properties of crystalline rock are being studied in situ, were investigated using X-ray microtomography and SEM-EDS...
October 26, 2017: Journal of Microscopy
Toshinari Ezawa, Yutaka Inoue, Isamu Murata, Koichi Takao, Yoshiaki Sugita, Ikuo Kanamoto
In this study, the physicochemical properties and solubility of inclusion complexes of ground mixtures (GMs) of piperine (PP), a pungent ingredient of pepper, with α- and γ-cyclodextrin (CD) were studied. From the solubility results, the PP/αCD inclusion molar ratio was determined to be 1/2, while that of PP/γCD was 1/1, according to the AP-type phase diagram of PP/αCD and the BS-type one of PP/γCD. The powder X-ray diffraction and differential scanning calorimetry analyses confirmed the formation of GM complexes with molar ratios of PP/αCD = 1/2 and PP/γCD = 1/1...
October 25, 2017: AAPS PharmSciTech
Mauro Ferraro, Bram Trachet, Lydia Aslanidou, Heleen Fehervary, Patrick Segers, Nikolaos Stergiopulos
In order to advance the state-of-the-art in computational aortic biomechanics, we investigated the influence of (i) a non-uniform wall thickness, (ii) minor aortic side branches and (iii) a non-uniform axial stretch distribution on the location of predicted hotspots of principal strain in a mouse model for dissecting aneurysms. After 3 days of angiotensin II infusion, a murine abdominal aorta was scanned in vivo with contrast-enhanced micro-CT. The animal was subsequently sacrificed and its aorta was scanned ex vivo with phase-contrast X-ray tomographic microscopy (PCXTM)...
October 25, 2017: Annals of Biomedical Engineering
Korinna Bader, Manuel M Neidhardt, Tobias Wöhrle, Robert Forschner, Angelika Baro, Frank Giesselmann, Sabine Laschat
To probe the influence of electrostatic interactions on the mesomorphic self-assembly and phase behaviour of hybrid liquid crystals a series of crown ether/tyrosine hybrid systems was prepared by Steglich esterification of alkyl N-(tert-butoxycarbonyl)-l-tyrosinates with 4-carboxybenzo[15]crown-5 and 4-carboxybenzo[18]crown-6. The obtained derivatives allowed further manipulations at the NH functional group and complexation of the crown ether unit with NaI to give neutral or charged hybrid materials. All compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) measurements...
October 24, 2017: Soft Matter
Anna Zamir, Charlotte Hagen, Paul C Diemoz, Marco Endrizzi, Fabio Vittoria, Yujia Chen, Mark A Anastasio, Alessandro Olivo
Edge illumination (EI) is an x-ray phase-contrast imaging technique, exploiting sensitivity to x-ray refraction to visualize features, which are often not detected by conventional absorption-based radiography. The method does not require a high degree of spatial coherence and is achromatic and, therefore, can be implemented with both synchrotron radiation and commercial x-ray tubes. Using different retrieval algorithms, information about an object's attenuation, refraction, and scattering properties can be obtained...
October 2017: Journal of Medical Imaging
Jessica R Crawshaw, Marcus J Kitchen, Corinna Binder-Heschl, Marta Thio, Megan J Wallace, Lauren T Kerr, Charles C Roehr, Katie L Lee, Genevieve A Buckley, Peter G Davis, Andreas Flemmer, Arjan B Te Pas, Stuart B Hooper
BACKGROUND: Non-invasive ventilation is sometimes unable to provide the respiratory needs of very premature infants in the delivery room. While airway obstruction is thought to be the main problem, the site of obstruction is unknown. We investigated whether closure of the larynx and epiglottis is a major site of airway obstruction. METHODS: We used phase contrast X-ray imaging to visualise laryngeal function in spontaneously breathing premature rabbits immediately after birth and at approximately 1 hour after birth...
October 20, 2017: Archives of Disease in Childhood. Fetal and Neonatal Edition
Emma Bauer, Xavier Domingo, Cristina Balcells, Ibrahim H Polat, Margarita Crespo, Josefina Quirante, Josefa Badía, Laura Baldomà, Mercè Font-Bardia, Marta Cascante
The synthesis of six novel cyclometallated platinum(iv) iodido complexes is accomplished by intermolecular oxidative addition of methyl iodide (compounds 2a-2c) or iodine (compounds 3a-3c) upon cyclometallated platinum(ii) compounds [PtX{(CH3)2N(CH2)3NCH(4-ClC6H3)}] (1a-1c: X = Cl, CH3 or I). The X-ray molecular structures of platinum(ii) compound 1c and platinum(iv) compounds 3b and 3a' (an isomer of 3a) are reported. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), DNA interaction, topoisomerase I, IIα, and cathepsin B inhibition, and cell cycle arrest, apoptosis and ROS generation of the investigated complexes are presented...
November 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Gwenaelle Rousse, Hania Ahouari, Vladimir Pomjakushin, Jean-Marie Tarascon, Nadir Recham, Artem M Abakumov
We report on a thorough structural study on two members of layered fluorocarbonates KMCO3F (M = Ca, Mn). The Ca-based member demonstrates a phase transition at ∼320 °C, evidenced for the first time. The crystal structure of the high temperature phase (HT-KCaCO3F) was solved using neutron powder diffraction. A new Mn-based phase KMnCO3F was synthesized, and its crystal structure was solved from electron diffraction tomography data and refined from a combination of X-ray synchrotron and neutron powder diffraction...
November 6, 2017: Inorganic Chemistry
Juan A Núñez, Alice Goring, Eric Hesse, Philipp J Thurner, Philipp Schneider, Claire E Clarkin
3D imaging of the bone vasculature is of key importance in the understanding of skeletal disease. As blood vessels in bone are deeply encased in the calcified matrix, imaging techniques that are applicable to soft tissues are generally difficult or impossible to apply to the skeleton. While canals in cortical bone can readily be identified and characterised in X-ray computed tomographic data in 3D, the soft tissue comprising blood vessels that are putatively contained within the canal structures does not provide sufficient image contrast necessary for image segmentation...
October 16, 2017: Scientific Reports
T Ramos, J S Jørgensen, J W Andreasen
X-ray computerized tomography (CT) is a 3D imaging technique that makes use of x-ray illumination and image reconstruction techniques to reproduce the internal cross-sections of a sample. Tomographic projection data usually require an initial relative alignment or knowledge of the exact object position and orientation with respect to the detector. As tomographic imaging reaches increasingly better resolution, thermal drifts, mechanical instabilities, and equipment limitations are becoming the main dominant factors contributing to sample positioning uncertainties that will further introduce reconstruction artifacts and limit the attained resolution in the final tomographic reconstruction...
October 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Ken Vidar Falch, Mikhail Lyubomirsky, Daniele Casari, Anatoly Snigirev, Irina Snigireva, Carsten Detlefs, Marco Di Michiel, Ivan Lyatun, Ragnvald H Mathiesen
The current work represents the first implementation of Zernike phase contrast for compound refractive lens based x-ray microscopy, and also the first successful Zernike phase contrast experiment at photon energies above 12 keV. Phase contrast was achieved by fitting a compound refractive lens with a circular phase plate. The resolution is demonstrated to be sub-micron, and can be improved using already existing technology. The possibility of combining the technique with polychromatic radiation is considered, and a preliminary test experiment was performed with positive results...
October 3, 2017: Ultramicroscopy
I Asela, M Noyong, U Simon, J Andrades-Lagos, J Campanini-Salinas, D Vásquez-Velásquez, M Kogan, N Yutronic, R Sierpe
While 2-amino-4-(4-chlorophenyl)thiazole (AT) drug and thiazole derivatives have several biological applications, these compounds present some drawbacks, such as low aqueous solubility and instability. A new complex of βCD-AT has been synthesized to increase AT solubility and has been used as a substrate for the deposit of solid-state AuNPs via magnetron sputtering, thus forming the βCD-AT-AuNPs ternary system, which is stable in solution. Complex formation has been confirmed through powder X-ray diffraction and 1D and 2D nuclear magnetic resonance...
2017: PloS One
Heidi A Schwartz, Selina Olthof, Dominik Schaniel, Klaus Meerholz, Uwe Ruschewitz
1,3,3-Trimethylindolino-6'-nitrobenzopyrylospiran (SP-1) as an example of a photoswitchable spiropyran was loaded into the pores of different prototypical metal-organic frameworks, namely MOF-5, MIL-68(In), and MIL-68(Ga), by a vapor-phase process. The successful incorporation in the pores of the MOF was proven by X-ray powder diffraction, and the amount of the embedded photoswitchable guest was determined by X-ray photoelectron spectroscopy and elemental analysis. In contrast to the sterically hindered crystalline state, SP-1 embedded in solid MOF hosts shows photoswitching under irradiation with UV light from the spiropyran to its merocyanine form with a nearly complete photoisomerization...
November 6, 2017: Inorganic Chemistry
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