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https://www.readbyqxmd.com/read/28545253/encapsulation-of-the-antioxidant-r-%C3%AE-lipoic-acid-in-permethylated-%C3%AE-and-%C3%AE-cyclodextrins-thermal-and-x-ray-structural-characterization-of-the-1-1-inclusion-complexes
#1
Mino R Caira, Susan A Bourne, Buntubonke Mzondo
The naturally occurring compound α-lipoic acid (ALA) is implicated in manifold critical biological roles and its potent antioxidant properties and potential for treatment of various diseases have led to its widespread use as a dietary supplement. However, shortcomings of poor aqueous solubility and low thermal stability have hampered its development as a medicinal agent, prompting the use of cyclodextrins (CDs) to address these problems. The paucity of published structural data on the nature of the interactions between ALA and CDs motivated the present study, which describes the synthesis and X-ray structural elucidation of crystalline inclusion complexes between the biologically relevant R-(+)-α-lipoic acid (RALA) and the host molecules permethylated α-CD (TMA) and permethylated β-CD (TMB)...
May 23, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28545193/synthesis-characterization-and-cytotoxic-evaluation-of-graphene-oxide-nanosheets-in-vitro-liver-cancer-model
#2
Samah A Loutfy, Taher A Salaheldin, Marwa A Ramadan, Khaled Yehia Farroh, Zeinab F Abdallah, Tareq Youssef Abd Eloahed
Background: Graphene nanosheets have a broad spectrum of biomedical applications. Hepatocellular cancer (HCC) is a major health problem in the Egyptian population. Currently, treatment strategies are invasive and have several adverse side effects. Thus, other approaches are required for managing this aggressive type of cancer. Our objective here was to prepare and characterize graphene oxide nanosheets and evaluate cytotoxic effect at the molecular level in an in vitro human liver cancer cell model (HepG2)...
April 1, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/28545054/an-optimized-small-animal-tumour-model-for-experimentation-with-low-energy-protons
#3
Elke Beyreuther, Kerstin Brüchner, Mechthild Krause, Margret Schmidt, Rita Szabo, Jörg Pawelke
BACKGROUND: The long-term aim of developing laser based particle acceleration towards clinical application requires not only substantial technological progress, but also the radiobiological characterization of the resulting ultra-short and ultra-intensive particle beam pulses. After comprehensive cell studies a mouse ear tumour model was established allowing for the penetration of low energy protons (~20 MeV) currently available at laser driven accelerators. The model was successfully applied for a first tumour growth delay study with laser driven electrons, whereby the need of improvements crop out...
2017: PloS One
https://www.readbyqxmd.com/read/28544977/environmental-radiation-dosimetry-at-argentine-antarctic-marambio-base-64%C3%A2-13-s-56%C3%A2-43-w-preliminary-results
#4
Alba Zanini, Vicente Ciancio, Monica Laurenza, Marisa Storini, Adolfo Esposito, Juan Carlos Terrazas, Paolo Morfino, Alessandro Liberatore, Gustavo Di Giovan
The preliminary results obtained in the first environmental radiation dosimetry campaign performed in the Antarctic region are presented. This experiment is carried out in the framework of CORA (COsmic Rays in Antarctica) Project, a collaboration between Argentine and Italian institutions. After a feasibility study performed in the Antarctic summer 2013, a new campaign has been carried out, started in March 2015, to measure various components of cosmic ray induced secondary atmospheric radiation at the Argentine Marambio Base (Antarctica; 196 m a...
May 22, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28544849/co-catalytic-effects-of-cos2-on-activity-of-mos2-catalyst-for-electrochemical-hydrogen-evolution
#5
Ranjith Bose, Zhenyu Jin, Seokhee Shin, Sungjoon Kim, Sun Young Lee, Yo-Sep Min
MoS2 is a promising material to replace Pt catalyst for electrochemical hydrogen evolution reaction (HER). It is well known that the activity of the MoS2 catalyst in the HER is significantly promoted by doping cobalt atoms. Recently, the Co-Mo-S phase, in which cobalt atoms decorate the edge positions of the MoS2 slabs, has been identified as a co-catalytic phase in the Co-doped MoS2 (Co-MoSx) with a low Co content. Here, we report the effect of the incorporation of cobalt atoms on the chemical state of Co-MoSx catalyst which gives rise to the co-catalytic effect...
May 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28544781/pd-nanoparticles-immobilized-on-individual-calcium-carbonate-plate-derived-from-mussel-shell-waste-an-eco-friendly-catalyst-for-copper-free-sonogashira-coupling-reaction
#6
Trin Saetan, Chutiparn Lertvachirapaiboon, Ekgasit Sanong, Mongkol Sukwattanasinitt, Sumrit Wacharasindhu
Conversion of waste into high value materials has been considered an important sustainability strategy in modern chemical industries. Large volume of shell waste is generated globally from mussel cultivation. In this work, mussel shell wastes (Perna viridis) are transformed into individual calcium carbonate plate (ICCP) and apply as a support for heterogeneous catalyst. Palladium nanoparticles (3-6 nm) are deposited with even dispersion on ICCP surface as demonstrated by X-ray diffraction and scanning electron microscopy...
May 22, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28544757/eight-electron-silver-and-mixed-gold-silver-nanoclusters-stabilized-by-se-donor-ligands
#7
Wan-Ting Chang, Po-Yi Lee, Jian-Hong Liao, Samia Kahlal, Jean-Yves Saillard, Chen-Wei Liu
The first atomically and structurally precise silver-nanoclusters stabilized by Se-donor ligands, [Ag20{Se2P(OiPr)2}12] (3) and [Ag21{Se2P(OEt)2}12]+(4), have been isolated by ligand replacement reaction of [Ag20{S2P(OiPr)2}12] (1) and [Ag21{S2P(OiPr)2}12]+ (2), respectively. Further, doping reactions of 4 with Au(PPh3)Cl resulted in the formation of [AuAg20{Se2P(OEt)2}12]+, (5). Structures of 3, 4 and 5 were determined by single crystal X-ray diffraction. The anatomy of cluster 3 with an Ag20 core having C3 symmetry is very similar to that of its dithiophosphate analogue 1...
May 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544634/hydrogen-bond-driven-self-assembly-between-amidinium-cations-and-carboxylate-anions-a-combined-molecular-dynamics-nmr-spectroscopy-and-single-crystal-x-ray-diffraction-study
#8
Michael Thomas, Thomas Anglim Lagones, Martyna Judd, Mahbod Morshedi, Megan L O'Mara, Nicholas G White
A combination of molecular dynamics (MD), NMR spectroscopy, and single crystal X-ray diffraction (SCXRD) techniques was used to probe the self-assembly of para- and meta-bis(amidinium) compounds with para-, meta-, and ortho-dicarboxylates. Good concordance was observed between the MD and experimental results. In DMSO solution, the systems form several rapidly exchanging assemblies, in part because a range of hydrogen bonding interactions is possible between the amidinium and carboxylate moieties. Upon crystallization, the majority of the systems form 1D supramolecular polymers, which are held together by short N-H⋅⋅⋅O hydrogen bonds...
May 23, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28544632/understanding-the-limiting-factors-of-solvent-annealed-small-molecule-bulk-heterojunction-organic-solar-cells-from-a-chemical-perspective
#9
Aurelien Viterisi, Daniel Fernandez, Vijay Kumar Challuri, James William Ryan, Eugenia Martinez-Ferrero, Francesc Guispert-Guirado, Marta Martinez, Eduardo Escudero, Caterina Stenta, Lluis Francisco Marsal, Emilio Palomares
A detailed account on the limiting factors of solvent annealed bulk-heterojunction small molecule organic solars cell is given. This account is based on the extensive characterization of solar cell devices made from a library of five diketopyrolopyrole (DPP) donor dyes. Their chemical structure is designed in such a way as to provide insights on the energetics of solar cell active layer microstructure formation. Numerous chemical and physical properties of the active layers are assessed and interrelated such as light absorption, molecular packing in the solid state, crystal-forming properties in thin films, charge carrier mobility and charge carrier recombination kinetics...
May 24, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28544565/base-selective-five-versus-six-membered-ring-annulation-in-palladium-catalyzed-c-c-coupling-cascade-reactions-new-access-to-electron-poor-polycyclic-aromatic-dicarboximides
#10
Sabine Seifert, David Schmidt, Kazutaka Shoyama, Frank Würthner
Palladium-catalyzed base-selective annulation of dibromonaphthalimide to different aryl boronate esters by combined Suzuki-Miyaura cross-coupling and direct C-H arylation afforded a series of new five- and six-membered ring annulated electron-poor polycyclic aromatic hydrocarbons. Cesium carbonate (Cs2 CO3 ) as auxiliary base in these C-C coupling cascade reactions led exclusively to six-membered ring annulation, while the use of organic base diazabicycloundecene (DBU) afforded the corresponding five-membered ring annulated products...
May 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544495/posterior-lumbar-interbody-fusion-with-interspinous-fastener-provides-comparable-clinical-outcome-and-fusion-rate-to-pedicle-screws
#11
Wei-Min Huang, Xing-Ming Yu, Xiao-Duo Xu, Ruo-Xian Song, Li-Li Yu, Xiu-Chun Yu
OBJECTIVE: To investigate the clinical feasibility and validity of interspinous fastener (ISF) for lumbar degenerative diseases. METHODS: From October 2013 to March 2014, a total of 46 patients suffering from lumbar degenerative diseases underwent posterior lumbar interbody fusion (PLIF) randomly augmented by ISF or pedicle screws. The clinical outcome was primarily measured by Oswestry Disability Index (ODI) score. The minimal clinical important difference (MCID) was defined as an eight-point decrease in ODI...
May 24, 2017: Orthopaedic Surgery
https://www.readbyqxmd.com/read/28544434/strain-stiffening-hydrogels-through-self-assembly-and-covalent-fixation-of-semi-flexible-fibers
#12
Rint P Sijbesma, Marcos Fernandez-Castano Romera, Clément Guibert, Ilja K Voets, Cornelis Storm
Biomimetic, strain-stiffening materials are reported, made through self-assembly and covalent fixation of small building blocks to form fibrous hydrogels able to stiffen by an order of magnitude in response to applied stress. The gels consist of semi-flexible rodlike micelles of bisurea bolaamphiphiles with oligo(ethylene oxide) (EO) outer blocks and a polydiacetylene (PDA) backbone. The micelles are fibers composed of 9-10 ribbons. A gelation method based on Cu-catalyzed azide-alkyne cycloaddition (CuAAC) was developed that leads to strain-stiffening hydrogels with unusual yet universal linear and nonlinear stress-strain response...
May 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544372/deprotonation-of-a-seemingly-hydridic-diborane-6-to-build-a-b-b-bond
#13
Thomas Kaese, Hendrik Budy, Michael Bolte, Hans-Wolfram Lerner, Matthias Wagner
Deprotonation of the doubly arylene-bridged diborane(6) derivative 1H2 with (Me3 Si)3 CLi or (Me3 Si)2 NK gives the B-B σ-bonded species M[1H] in essentially quantitative yields (THF, room temperature; M=Li, K, arylene=4,4'-di-tert-butyl-2,2'-biphenylylene). With nBuLi as the base, the yield of Li[1H] drops to 20 % and the 1,1-bis(9-borafluorenyl)butane Li[2H] is formed as a side product (30 %). In addition to the 1,1-butanediyl fragment, the two boron atoms of Li[2H] are linked by a μ-H bridge. In the closely related molecule Li[3H], the corresponding μ-H atom can be abstracted with (Me3 Si)3 CLi to afford the B-B-bonded conjugated base Li2 [3] (THF, 150 °C; 15 %)...
May 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544371/high-loading-crystals-of-tetraaryladamantanes-and-the-uptake-and-release-of-aromatic-hydrocarbons-from-the-gas-phase
#14
Clemens Richert, Pierre-Emmanuel Alexandre, Alexander Schwenger, Wolfgang Frey
Recently, a tetraphenyladamantane octamethylether was shown to encapsulate a wide range of small molecules in its crystals. Uptake and release from the liquid phase were demonstrated, and crystalline inclusion complexes were prepared that act as formulation for obnoxious reagents. Less than two equivalents of guest molecules were found in the crystal structures, though. Here we report the synthesis of 1,3,5,7-tetrakis(2,4-diethoxyphenyl)-adamantane (TEO) and twelve X-ray crystal structures that contain up to 3...
May 23, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28544340/a-high-valent-non-heme-%C3%AE-oxo-mniv-dimer-generated-from-a-thiolate-bound-mnii-complex-and-o2
#15
Carole Duboc, Deborah Brazzolotto, Fabián G Cantú Reinhard, Julian Smith-Jones, Marius Retegan, Lucia Amidani, Abayomi S Faponle, Kallol Ray, Christian Philouze, Sam P de Visser, Marcello Gennari
This study deals with the unprecedented reactivity of dinuclear non heme MnII-thiolate complexes with O2, which dependent on the protonation state of the initial MnII dimer selectively generates either a di-μ-oxo or μ-oxo-μ-hydroxo MnIV complex. Both dimers have been characterized by different techniques including single-crystal X-ray diffraction and mass spectrometry. Oxygenation reactions carried out with labeled 18O2 unambiguously shows that the oxygen atoms present in the MnIV dimers originate from O2...
May 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544330/%C3%AE-radical-phosphines-synthesis-structure-and-reactivity
#16
Manuel Alcarazo, Lianghu Gu, Yiying Zheng, Estela Haldón, Richard Goddard, Eckhard Bill, Walter Thiel
A series of phosphines featuring a persistent radical were synthesized in two steps by condensation of dialkyl-/diarylchlorophosphines with stable cyclic (alkyl)(amino)carbenes (cAACs) followed by one-electron reduction of the corresponding cationic intermediates. Structural, spectroscopic and computational data indicate that the spin density in these phosphines is mainly localized on the original carbene carbon from the cAAC fragment; thus, it remains in the α-position to the central phosphorus. The potential of these α-radical phosphines to serve as spin-labeled ligands is demonstrated through the preparation of several Au(I) derivatives, which were also structurally characterized by single-crystal X-ray diffraction...
May 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544304/strong-improvement-of-long-term-chemical-and-thermal-stability-of-plasmonic-silver-nanoantennas-and-films
#17
Xiaolong Wang, Christian Santschi, Olivier J F Martin
Silver (Ag) nanostructures and thin films are advantageous plasmonic materials as they have significantly lower losses than gold (Au). Unfortunately, Ag nanostructures suffer from poor chemical and thermal stability, which limit their applications. Here, the mechanisms leading to the deterioration of Ag nanostructures are clarified. It is first shown that oxygen alone cannot oxidize Ag nanostructures. Then, experiments using X-ray photoelectron spectroscopy reveal that the amount of sulfur in ambient air is too low for efficient tarnishing of the Ag surface...
May 24, 2017: Small
https://www.readbyqxmd.com/read/28544234/clinical-microscopic-and-ultrastructural-findings-in-a-case-of-short-anagen-syndrome
#18
Jose M Martin, Encarnacion Montesinos, Sara Sanchez, Catalina Torres, Dolores Ramon
Short anagen syndrome is an uncommon and recently described disease characterized by many telogen hairs and short maximum hair length. We report here the case of a 3-year-old girl whose short, sparse, fine hair since birth was consistent with short anagen syndrome. X-ray microanalysis demonstrated normal composition of the main bioelements of her hairs.
May 23, 2017: Pediatric Dermatology
https://www.readbyqxmd.com/read/28544178/transition-metal-nitride-core-noble-metal-shell-nanoparticles-as-highly-co-tolerant-catalysts
#19
Aaron Garg, Maria Milina, Madelyn Ball, Daniela Zanchet, Sean T Hunt, James A Dumesic, Yuriy Roman-Leshkov
Core-shell architectures offer an effective way to tune and enhance the properties of noble metal catalysts. Here, we demonstrate the synthesis of Pt shell on titanium tungsten nitride core nanoparticles (Pt/TiWN) by high temperature ammonia nitridation of a parent core-shell carbide material (Pt/TiWC). X-ray photoelectron spectroscopy revealed significant core-level shifts for Pt shells supported on TiWN cores, corresponding to increased stabilization of the Pt valence d-states. The modulation of the electronic structure of the Pt shell by the nitride core translated into enhanced CO tolerance during hydrogen electrooxidation in the presence of CO...
May 25, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544098/crystal-structure-of-the-sensor-domain-of-baes-from-serratia-marcescens-fs14
#20
Ya Zhang, Shenshen Qiu, Shanshan Jia, Dongqing Xu, Tingting Ran, Weiwu Wang
The sensor histidine kinases of two-component signal-transduction systems (TCSs) are essential for bacteria to adapt to variable environmental conditions. The two-component regulatory system BaeS/R increases multidrug and metal resistance in Salmonella and Escherichia coli. In this study, we report the X-ray structure of the periplasmic sensor domain of BaeS from Serratia marcescens FS14. The BaeS sensor domain (34-160) adopts a mixed α/β-fold containing a central four-stranded antiparallel β-sheet flanked by a long N-terminal α-helix and additional loops and a short C-terminal α-helix on each side...
May 24, 2017: Proteins
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