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X-ray diffraction

Hira Tahir, Yasser Shahzad, Laura J Waters, Talib Hussain, Abid Mehmood Yousaf, Tariq Mahmood, Rizwan Sheikh
Poor aqueous solubility is often linked with a poor dissolution rate and ultimately, limited bioavailability of pharmaceutical compounds. This study describes the application of mesoporous materials (Syloid 244 and Syloid AL1) in improving the dissolution rate of a drug with poor aqueous solubility, namely artemether, utilising different processing methods including physical mixing, co-grinding and solid dispersions prepared by solvent evaporation and the lyophilisation technique. The prepared formulations were extensively characterised for their solid-state properties and the drug release attributes were studied...
November 19, 2017: European Journal of Pharmaceutical Sciences
Hom N Sharma, Elizabeth A Sangalang, Cheng K Saw, Gareth A Cairns, William McLean, Robert S Maxwell, Long N Dinh
Measurements of equilibrium vapor pressures by effusion thermogravimetry and melting points by differential scanning calorimetry reveal that the melting temperature and equilibrium vapor pressures of 1,4-bis(phenylethynyl)benzene (DEB) do not vary monotonically with the hydrogenation extent. Contrary to intuition which suggests increasing volatility with hydrogenation, results indicate decreasing volatility for the first two hydrogenation steps before a non-monotonic upward trend, in which trans-isomers are less volatile...
November 21, 2017: Journal of Chemical Physics
Brian M May, Young-Sang Yu, Martin Holt, Fiona C Strobridge, Ulrike Bösenberg, Clare P Grey, Jordi Cabana
Redox-driven phase transformations in solids determine the performance of lithium-ion batteries, crucial in the technological transition from fossil fuels. Couplings between chemistry and strain define reversibility and fatigue of an electrode. The accurate definition of all phases in the transformation, their energetics and nanoscale location within a particle produces fundamental understanding of these couplings needed to design materials with ultimate performance. Here we demonstrate that scanning X-ray diffraction microscopy (SXDM) extends our ability to image battery processes in single particles...
November 22, 2017: Nano Letters
Anton Werwein, Florian Maaß, Leonhard Y Dorsch, Oliver Janka, Rainer Pöttgen, Thomas C Hansen, Justin Kimpton, Holger Kohlmann
The hydrogenation properties of Laves phases LnMg2 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb) were investigated by thermal analysis, X-ray, synchrotron, and neutron powder diffraction. At 14.0 MPa hydrogen gas pressure and 393 K, PrMg2 and NdMg2 take up hydrogen and form the colorless, ternary hydrides PrMg2H7 (P41212, a = 632.386(6) pm, c = 945.722(11) pm) and NdMg2H7 (P41212, a = 630.354(9) pm, c = 943.018(16) pm). The crystal structures were refined by the Rietveld method from neutron powder diffraction data on the deuterides (PrMg2D7, P41212, a = 630...
November 22, 2017: Inorganic Chemistry
Aliakbar Gholampour, Meisam Valizadeh Kiamahalleh, Diana N H Tran, Togay Ozbakkaloglu, Dusan Losic
Graphene materials have been extensively explored and successfully used to improve performances of cement composites. These formulations were mainly optimized based on different dosages of graphene additives, but with lack of understanding how other parameters such as surface chemistry, size, charge, and defects of graphene structures could impact on physiochemical and mechanical properties of final material. This paper presents the first experimental study to evaluate the influence of oxygen functional groups of graphene and defectiveness of graphene structures on the axial tension and compression properties of graphene-cement mortar composites...
November 22, 2017: ACS Applied Materials & Interfaces
Eloy Isarain-Chávez, Maria Dolors Baró, Carlos Alcantara, Salvador Pané, Jordi Sort, Eva Pellicer
Mesoporous Fe-Pt thin films are obtained by micelle-assisted electrodeposition onto metallic substrates with dissimilar activity (namely, gold, copper, and aluminum seed-layers evaporated on Si/Ti) under constant applied potential (E= -1.1 V vs. Ag/AgCl) and deposition time (600 s). The amphiphilic triblock copolymer Pluronic P-123 is used as a soft-template to guide the formation of mesopores. The occurrence of pores (ca. 7 nm in diameter) with narrow size distribution, regularly distributed over the surface, is observed in all cases...
November 22, 2017: ChemSusChem
Srinivas Katam, Prabusankar Ganesan
Two mega size copper(i) cubic cages, [{Cu(Bptp)1.5}8(PF6(-))](PF6(-))7 (1) and [{Cu(Bpsp)1.5}8(PF6(-))](PF6(-))7 (2), supported by imidazole-2-chalcogenone ligands (Bptp = 2,6-bis(1-isopropylimidazole-2-thione)pyridine and Bpsp = 2,6-bis(1-isopropylimidazole-2-selone)pyridine) have been synthesized and characterized. The formation of ionic salts 1 and 2 was confirmed by FT-IR, multinuclear ((1)H, (13)C, (31)P and (19)F) NMR, UV-vis, TGA, CHN analysis, BET analysis, single crystal X-ray diffraction and powder X-ray diffraction techniques...
November 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Roosevelt D S Bezerra, Régis C Leal, Mateus S da Silva, Alan I S Morais, Thiago H C Marques, Josy A Osajima, Andréia B Meneguin, Hernane da S Barud, Edson C da Silva Filho
Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution...
November 22, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Chengbo Gu, Ziwei Liu, Xiaohan Yuan, Wang Li, Yuangang Zu, Yujie Fu
Vitexin, a natural flavonoid found in many medicinal plants, is well known for its rich pharmacological activities. However, the poor water solubility of vitexin has limited its therapeutic application. The aim of this study was to prepare the nanoparticles of vitexin by combining the antisolvent precipitation (ASP) and high pressure homogenization (HPH) approaches followed by lyophilization for improving the dissolution rate of this poorly water-soluble drug. The effects of main factors influencing the mean particle size (MPS) of vitexin were investigated and optimized...
November 22, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Saijie Zhu, Huisheng Gao, Sreehari Babu, Sudhakar Garad
Solubilization of parenteral drugs is a high unmet need in both pre-clinical and clinical drug development. Recently, co-amorphous drug formulation has emerged as a new strategy to solubilize orally dosed drugs. The aim of the present study is to explore the feasibility of using the co-amorphous strategy to enable the dosing of parenteral zwitterionic drugs at a high concentration. A new screening procedure was established with solubility as the indicator for co-amorphous co-former selection, and lyophilization was established as the method for co-amorphous formulation preparation...
November 22, 2017: Molecular Pharmaceutics
Wiebke Saal, Alfred Ross, Nicole Wyttenbach, Jochem Alsenz, Martin Kuentz
The methacrylate-copolymer Eudragit® EPO (EPO) has previously shown to greatly enhance solubilization of acidic drugs via ionic interactions and by multiple hydrophobic contacts with polymeric side chains. The latter type of interaction could also play a role for solubilization of other compounds than acids. The aim of this study was therefore to investigate the solubility of six poorly soluble bases in presence and absence of EPO by quantitative ultra-pressure liquid chromatography with concomitant X-ray powder diffraction (XRPD) analysis of the solid state...
November 22, 2017: Molecular Pharmaceutics
Rui Liu, Guiliang Xu, Qi Li, Shiyao Zheng, Guorui Zheng, Zhengliang Gong, Yixiao Li, Elizaveta Kruskop, Riqiang Fu, Zonghai Chen, Khalil Amine, Yong Yang
Development of highly reversible multi-electron reaction per redox center in NASICON-structured cathode materials is desired to improve the energy density of Sodium-ion batteries. Here, we investigated more than one electron storage of Na in Na3VCr(PO4)3. Combining a series of advanced characterization techniques such as ex situ 51V solid-state nuclear magnetic resonance, X-ray absorption near edge structure and in situ X-ray diffraction, we reveal that, V3+/V4+ and V4+/V5+ redox couples in the materials can be accessed, leading to 1...
November 22, 2017: ACS Applied Materials & Interfaces
Hemalatha Parangusan, Deepalekshmi Ponnamma, Mariam Al Ali Al-Maadeed, Alagar Marimuthu
Pure ZnO and Yttrium doped (Y-doped) ZnO at various mol% with flower-like nanostructures are synthesized by a microwave-assisted sol-gel method, followed by investigating the morphologies, crystal structures, optical properties and photocatalytic performances. While the phase formations are detected by X-ray diffraction technique, both scanning and transmission electron microscopy images clearly depict the flower-like morphology of ZnO and Y-doped ZnO samples. Formation of flower petals are from the nanoparticles that grew and connected by orientation attachment process...
November 22, 2017: Photochemistry and Photobiology
Xu-Jian Yang, Zhihong Xu, Hong Shen
Iron plaque (IP) is valuable in nutrient management and contaminant tolerance for rice (Oryza sativa) because it can adsorb various nutrients and toxic ions. Crystalline ratio (CR) can be defined as the proportion of crystalline iron (CI) to total IP to describe IP crystallinity. Although the knowledge on IP has abounded, the information on the relationship among its formation condition, surface properties, and CR remains insufficient. In this study, quartz sand-soil cultivation with rice was conducted to explore the effect of drying-submergence alternation (DSA) on CI, amorphous iron (AI), CR, root oxidizing capacity (ROC), and surface properties of IP with different treatment durations and at different stages...
November 21, 2017: Environmental Science and Pollution Research International
Gui-Yang Xia, Tie Yao, Bing-Yang Zhang, Yang Li, Ning Kang, Shi-Jie Cao, Li-Qin Ding, Li-Xia Chen, Feng Qiu
Four new steroid glycosides, withapubesides A-D (1-4), were isolated from the stems of Physalis pubescens L. Their structures were elucidated primarily by NMR experiments. The absolute configurations of 1 and 2 were deduced by single-crystal X-ray diffraction and ECD data analysis, respectively. Compound 3 has shown significant inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages with an IC50 value of 12.8 μM and moderate cytostatic activity against human carcinoma cells (786-O, C4-2B, 22Rvl, A375 and A375S2) with IC50 values in the range of 3...
November 22, 2017: Organic & Biomolecular Chemistry
Lorenzo Biancalana, Stefano Zacchini, Nicola Ferri, Maria Giovanna Lupo, Guido Pampaloni, Fabio Marchetti
The new complexes [RuCl2(η(6)-p-cymene)(κP-Ph2PR)] [R = 4-C6H4OSiMe2(t)Bu, 1; R = 4-C6H4Br, 2; R = OC([double bond, length as m-dash]O)CHCl2, 3; R = OPh, 4; R = O(2-C6H4SiMe2(t)Bu), 5] and [Ru(C2O4)(η(6)-p-cymene){κP-Ph2PO(2-C6H4(SiMe2(t)Bu))}], 6, were obtained in 83-98% yield from Ru(ii) arene precursors by three different synthetic strategies. The unprecedented phosphine Ph2P(O(2-C6H4SiMe2(t)Bu)) was synthesized in 86% yield from 2-C6H4Br(OSiMe2(t)Bu) and Ph2PCl, via intramolecular oxygen to carbon 1,3 migration of the silyl group (retro-Brook rearrangement)...
November 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Chun-Ting He, Zi-Ming Ye, Yan-Tong Xu, Dong-Dong Zhou, Hao-Long Zhou, Da Chen, Jie-Peng Zhang, Xiao-Ming Chen
The pore size and framework flexibility of hosts are of vital importance for molecular recognition and related applications, but accurate control of these parameters is very challenging. We use the slight difference of metal ion size to achieve continuous hundredth-nanometer pore-size adjustments and drastic flexibility modulations in an ultramicroporous metal-organic framework, giving controllable N2 adsorption isotherm steps, unprecedented/reversed loading-dependence of H2 adsorption enthalpy, quadrupole-moment sieving of C2H2/CO2, and an exceptionally high working capacity for C2H2 storage under practical conditions (98 times that of an empty cylinder)...
November 1, 2017: Chemical Science
Yuanting Su, Yongxin Li, Rakesh Ganguly, Rei Kinjo
Single-electron oxidation of neutral boryl-linked tetraaminoethylene derivatives 4 led to the formation of radical cations 4˙(+) , which have been isolated and fully characterized. X-ray diffraction analysis, EPR spectroscopy, and computational studies revealed that the unpaired electron is delocalized over the B2N4C2 skeleton and the spin density mainly resides on the carbon and boron atoms.
November 1, 2017: Chemical Science
Yue Guo, Sung Heum Park, Byung Chun Choi, Jung Hyun Jeong, Jung Hwan Kim
A Bi(3+) and Eu(3+) ion co-doped Ba9Lu2Si6O24 single-phased phosphor was synthesized successfully via a conventional high-temperature solid-state reaction. X-ray diffraction, crystal structure analysis, diffuse reflectance and luminescent spectra, quantum efficiency measurements, and thermal stability analysis were applied to investigate the phase, structure, luminescent and thermal stability properties. From the analyses of the crystal structure and luminescent spectra, we observed four discernible Bi(3+) luminescent centers with peaks at ~363...
November 21, 2017: Scientific Reports
Wei Liu, Xuebang Wu, Yunfeng Liang, Changsong Liu, Caetano R Miranda, Sandro Scandolo
High-pressure single-crystal X-ray diffraction method with precise control of hydrostatic conditions, typically with helium or neon as the pressure-transmitting medium, has significantly changed our view on what happens with low-density silica phases under pressure. Coesite is a prototype material for pressure-induced amorphization. However, it was found to transform into a high-pressure octahedral (HPO) phase, or coesite-II and coesite-III. Given that the pressure is believed to be hydrostatic in two recent experiments, the different transformation pathways are striking...
November 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
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