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https://www.readbyqxmd.com/read/28813058/fine-tuning-of-catalytic-and-sorption-properties-of-metal-organic-frameworks-via-in-situ-ligand-exchange
#1
Peng Wang, Kai Chen, Qing Liu, Huai-Wei Wang, Mohammad Azam, Saud I Al-Resayes, Yi Lu, Wei-Yin Sun
Metal-organic frameworks (MOFs) are gaining considerable attention not only because of their diverse structures but also due to their interesting properties and potential applications. However, fabrication of MOFs with desired structures and properties remains a great challenge. In this study, a strategy based on ligand exchange via single-crystal-to-single-crystal (SCSC) transformation has been undertaken, which can be used to achieve MOFs not available by direct synthesis and also to enrich the family of isoreticular MOFs...
August 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28813050/on-surface-synthesis-of-heptacene-and-its-interaction-with-a-metal-surface
#2
Malte Zugermeier, Manuel Gruber, Martin Schmid, Benedikt P Klein, Lukas Ruppenthal, Philipp Müller, Ralf Einholz, Wolfgang Hieringer, Richard Berndt, Holger F Bettinger, J Michael Gottfried
Heptacene was generated by surface-assisted didecarbonylation of an α-diketone precursor on a Ag(111) surface. Monitoring of the surface reaction and characterization of the adsorbed heptacene was performed with scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and density functional theory (DFT) calculations. The surface-assisted formation of heptacene occurs around 460 K. Both the heptacene and the precursor molecules are oriented along the high-symmetry directions of the (111) surface and their molecular π systems face towards the substrate...
August 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28813044/short-bent-core-molecules-x-ray-polarization-dielectricity-texture-and-electro-optics-investigations
#3
S Torgova, S P Sreenilayam, Yu P Panarin, O Francescangeli, F Vita, J K Vij, E Pozhidaev, M Minchenko, C Ferrero, A Strigazzi
Bent-core liquid crystals based on 1,2,4-oxadiazole as a central unit have been the first mesogens to exhibit a ferroelectric response in the nematic phase. This behavior has been widely recognized as due to the presence of smectic-like polar cybotactic clusters permeating the nematic phase. Unfortunately, these compounds exhibited rather high melting points, about 120 °C, due to the presence of four benzene rings in the molecules. Here we describe the synthesis and physical characterization of a new series of BC mesogens, featuring the same bent core as the previous compounds but shorter outer substituents...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812999/synthesis-and-evaluation-of-a-sodium-alginate-4-aminosalicylic-acid-based-microporous-hydrogel-for-potential-viscosupplementation-for-joint-injuries-and-arthritis-induced-conditions
#4
Dharmesh R Chejara, Mostafa Mabrouk, Pradeep Kumar, Yahya E Choonara, Pierre P D Kondiah, Ravindra V Badhe, Lisa C du Toit, Divya Bijukumar, Viness Pillay
A microporous hydrogel was developed using sodium alginate (alg) and 4-aminosalicylic acid (4-ASA). The synthesized hydrogel was characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), Carbon-13 nuclear magnetic resonance ((13)C-NMR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Additonal carboxyl and hydroxyl functional groups of 4-ASA provided significant lubrication and stress-triggered sol-gel transition to the conjugated hydrogel...
August 16, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28812879/germanium-and-tin-monoxides-trapped-by-oxophilic-germylene-and-stannylene-ligands
#5
Yunxia Gao, Ying Yang, Wenjun Zheng, Yuanyuan Su, Xiang Zhang, Herbert W Roesky
Germanium and tin monoxides (MO, M = Ge, Sn) were trapped by the 1,2,4-diazaphospholide-based germylene and stannylene M[3,5-tBu2dp]2 (M = Ge (2), Sn (3)), resulting in the Lewis acid-base adduct of composition M(μ-O)[M{η(1)(N)-(3,5-tBu2dp)}2]2 (M = Ge (4), Sn (5)). Compounds 4 and 5 were characterized by single-crystal X-ray structural analysis. The bonding features of 4 and 5 were supported by DFT calculations.
August 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28812878/nanomechanical-imaging-of-the-diffusion-of-fullerene-into-conjugated-polymer
#6
Dong Wang, Ken Nakajima, Feng Liu, Shaowei Shi, Thomas P Russell
The large Young's modulus difference between chemically modified fullerene (PCBM) and a conjugated polymer was used to nanomechanically map the diffusion of PCBM into PTB7, a high efficiency low band gap conjugated polymer. The sharp tip in nanomechanical atomic force microscopy (AFM) ensures a high-resolution nanomechanical characterization of the diffusion front, with the intrinsic benefits of revealing the mechanical properties of the mixtures. Localized structure changes induced by diffusion were investigated by grazing incidence x-ray diffraction methods...
August 16, 2017: ACS Nano
https://www.readbyqxmd.com/read/28812877/scru2b3-and-sc2rub6-borides-featuring-a-2d-infinite-boron-clustering
#7
Leonid P Salamakha, Oksana Sologub, Berthold Stöger, Peter Franz Rogl, Monika Waas, Volodymyr B Kapustianyk, Ernst Bauer
Two borides, ScRu2B3 and Sc2RuB6, were obtained by argon-arc melting of the elements followed by annealing at 800 °C. ScRu2B3 exhibits a new structure type with the space group Cmcm (a = 3.0195(2) Å, b = 15.4056(8) Å, c = 5.4492(3) Å; single crystal X-ray data; RF(2) = 0.0105). Sc2RuB6 adopts the Y2ReB6-type structure (space group Pbam; a = 8.8545(2) Å, b = 11.1620(3) Å, c = 3.4760(1) Å; single crystal X-ray data; RF(2) = 0.0185). ScRu2B3 displays an unusual intergrowth of CeCo3B2- and AlB2-related slabs; a striking feature is a boat configuration of puckered boron hexagons within infinite graphite like boron layers (6(3) nets)...
August 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28812873/ultrathin-manganese-based-metal-organic-framework-nanosheets-low-cost-and-energy-dense-lithium-storage-anodes-with-the-coexistence-of-metal-and-ligand-redox-activities
#8
Chao Li, Xiaoshi Hu, Wei Tong, Wensheng Yan, Xiaobing Lou, Ming Shen, Bingwen Hu
We herein demonstrate the fabrication of Mn- and Ni-based ultrathin metal-organic framework nanosheets with the same coordination mode (defined as 'Mn-UMOFNs' and 'Ni-UMOFNs', respectively) through an expedient and versatile ultrasonic approach, and scrutinize their electrochemical properties as anode materials for rechargeable lithium battery for the first time. The obtained Mn-UMOFNs with structure advantages over Ni-UMOFNs (thinner nanosheets, smaller metal-ion radius, higher specific surface area) exhibit high reversible capacity (1187 mAh g-1 at 100 mA g-1 for 100 cycles), excellent rate capability (701 mAh g-1 even at 2 A g-1), rapid Li+ diffusion coefficient (2...
August 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28812749/radical-driven-processes-within-a-peptidic-sequence-of-type-i-collagen-upon-single-photon-ionisation-in-the-gas-phase
#9
Lucas Schwob, Mathieu Lalande, Dmitrii Egorov, Jimmy Rangama, Ronnie Hoekstra, Violaine Vizcaino, Thomas Schlathölter, Jean-Christophe Poully
We report on an experimental single-photon absorption study on gas-phase protonated collagen peptides employing a combination of mass spectrometry and synchrotron radiation. Partial ion yields for the main photoabsorption products vary steadily with photon energy over the range from 14 to 545 eV. At low energy, non-dissociative photoionisation competes with neutral molecule loss from the precursor ion, whereas fragmentation of the peptide backbone dominates at soft X-ray energies. Neutral molecule losses from the ionised peptide are found to have low energy barriers and most likely involve amino-acid residue side-chains with radical character, in particular aspartic acid...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28812351/structural-investigation-of-cesium-lead-halide-perovskites-for-high-efficiency-quantum-dot-light-emitting-diodes
#10
Quyet Van Le, Jong Beom Kim, Soo Young Kim, Byeongdu Lee, Dong Ryeol Lee
In this study, we have intensively investigated the effect of the reaction temperature of hot-injection method on the structural properties of CsPbX3 (X: Br, I, Cl) perovskite nanocrystals (NCs) using the small- and wide-angle X-ray scattering. Furthermore, light emitting diodes (LEDs) performance as well as photoluminescence characteristics for high-efficient LEDs is compared with reaction temperature. It is confirmed that the size of the NCs decreased as the reaction temperature decreased, resulting stronger quantum confinement...
August 16, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28812225/enhancement-of-ocular-efficacy-of-aceclofenac-using-biodegradable-plga-nanoparticles-formulation-and-characterization
#11
Rajesh Katara, Sameer Sachdeva, Dipak K Majumdar
In the present study, an effort was made to design poly (D, L-lactide-co-glycolide) acid nanoparticles of aceclofenac by direct precipitation method. The nanoparticles were found to have adequate particle size range for ocular administration of 162.6 to 244.13 nm with nearly spherical shape and with zeta potential of - 21.5 to - 25.5 mV. Drug entrapment efficiency of nanoparticle formulations ranged from 42.9 to 92.68%. Differential scanning calorimetric (DSC) and powder X-ray diffraction (PXRD) studies depicted that the drug incorporated in nanoparticles was found to be in amorphous state...
August 15, 2017: Drug Delivery and Translational Research
https://www.readbyqxmd.com/read/28812174/-magnetic-resonance-imaging-mri-diagnostics-in-axial-spondyloarthritis
#12
T Witte, X Baraliakos
BACKGROUND: Axial spondyloarthritis (axSpA) is a frequent disorder, which is difficult to diagnose in the early phase. Currently, magnetic resonance imaging (MRI) of the sacroiliac joints and the spine is frequently applied in this phase, when conventional X rays still provide inconclusive results. OBJECTIVE: To explain the typical pathological results and the role of MRI in diagnosing axSpA. RESULTS: The use of MRI of the sacroiliac joints plays a central role in the assessment of the Spondyloarthritis International Association Society (ASAS) classification criteria of axSpA...
August 15, 2017: Zeitschrift Für Rheumatologie
https://www.readbyqxmd.com/read/28812114/-thoracic-and-abdominal-imaging-in-immunocompromised-patients
#13
REVIEW
J R Kroeger, D Maintz, D-H Chang
The number of patients with immunosuppression is rising worldwide. The spectrum of diseases and pathogens in these patients differs widely from that of immunocompetent patients due to frequent opportunistic infections. Symptoms are sometimes unspecific, and imaging plays a key role in the management of these patients. The lungs are a frequent site of infection in immunosuppressed patients. Chest X‑ray is the starting point for radiological diagnostics, but shows only limited sensitivity and specificity for infections with atypical pathogens...
August 15, 2017: Medizinische Klinik, Intensivmedizin und Notfallmedizin
https://www.readbyqxmd.com/read/28812090/zero-charged-catanionic-lamellar-liquid-crystals-doped-with-fullerene-c60-for-potential-applications-in-tribology
#14
Mengjun Chen, Baoyong Liu, Xiaolin Wang, Yanxu Fu, Jingcheng Hao, Hongguang Li
The formation of lamellar liquid crystals (LLCs) has been demonstrated in a few salt-free catanionic surfactant systems and their properties have been well documented. However, examples of their combination with other materials are relatively rare. Herein, a salt-free zero-charged catanionic surfactant with low chain melting temperature was prepared by mixing equimolar tetradecyltrimethylammonium oxide (TTAOH) and oleic acid (OA) in water, and its concentration-dependent aggregate transition was investigated...
August 16, 2017: Soft Matter
https://www.readbyqxmd.com/read/28812087/spatial-differentiation-of-br%C3%A3-nsted-acid-sites-by-probe-molecule-in-zeolite-usy-using-synchrotron-x-ray-powder-diffraction
#15
Lin Ye, Ivo Teixeira, Benedict T W Lo, Pu Zhao, S C Edman Tsang
By combining synchrotron X-ray powder diffraction, Rietveld refinement and the use of a probe molecule, Brønsted Acid Sites (BAS) of different strengths in steam-treated USY zeolite can be for the first time spatially differentiated: this enables the analysis of different acid-catalysed reactions of dimethylfuran (biomass) by the zeolite using a definitive site blockage strategy.
August 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28812074/three-dimensional-microtissues-as-an-in-vitro-model-for-personalized-radiation-therapy
#16
Yuting Qiu, Dandan Ning, Peipei Zhang, Stephanie Curly, Yong Qiao, Liyuan Ma, Ming Su
This paper describes the use of 3D microtissues as an intermediate model between the 2D cell culture and the animal model to assess radiation-induced cellular and DNA damage in the context of personalized radiation therapy. An agarose microwell array was used to generate 3D microtissues with controlled size and shape. The microtissues were exposed to X-ray radiation of various doses, and the radiation damage to cells was examined using a variety of techniques with different end points. Damage to cell membranes and reduction in metabolic activity were examined with the MTT assay and dye inclusion assay...
August 16, 2017: Analyst
https://www.readbyqxmd.com/read/28812064/chiral-cobalt-ii-complex-catalyzed-friedel-crafts-aromatization-for-the-synthesis-of-axially-chiral-biaryldiols
#17
Chaoran Xu, Haifeng Zheng, Bowen Hu, Xiaohua Liu, Lili Lin, Xiaoming Feng
An efficient atroposelective synthesis of axially chiral biaryldiols via asymmetric Friedel-Crafts aromatization between p-quinones and 2-naphthols was developed. A chiral cobalt(ii) complex of N,N'-dioxide enabled the process to generate axially chiral biaryldiols in up to 98% yield and 95% ee. A large range of substituents at different positions of p-quinones and 2-naphthols was tolerable. The configuration of the product and the chiral N,N'-dioxide-Co(ClO4)2 catalyst was identified by X-ray crystal diffraction analysis and a possible catalytic model was suggested...
August 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28812029/expanded-normal-weight-obesity-and-insulin-resistance-in-us-adults-of-the-national-health-and-nutrition-examination-survey
#18
Keilah E Martinez, Larry A Tucker, Bruce W Bailey, James D LeCheminant
This study aims to expand the evaluation of normal weight obesity (NWO) and its association with insulin resistance using an NHANES (1999-2006) sample of US adults. A cross-sectional study including 5983 men and women (50.8%) was conducted. Body fat percentage (BF%) was assessed using dual-energy X-ray absorptiometry. Expanded normal weight obesity (eNWO) categories, pairings of BMI and body fat percentage classifications, were created using standard cut-points for BMI and sex-specific median for BF%. Homeostatic model assessment-insulin resistance (HOMA-IR) levels were used to index insulin resistance...
2017: Journal of Diabetes Research
https://www.readbyqxmd.com/read/28811788/clinical-results-of-femoral-head-fracture-dislocation-treated-according-to-the-pipkin-classification
#19
Xiao Yu, Qing-Jiang Pang, Xian-Jun Chen
OBJECTIVE: To summarize the clinical results of femoral head fracture-dislocation treated according to Pipkin classification. METHODS: Atotal of 19 patients with femoral head fracture-dislocation were retrospectively analyzed from Mar. 2008 to Mar. 2015. According to the classification of Pipkin criteria, there were 4 cases in Type-I, 6 cases in Type-II, 6 cases in Type-IIIand 3 cases in Type-IV. Various procedures were taken according to the different types of the fracture, the time of the fracture, and the age of the patients...
May 2017: Pakistan Journal of Medical Sciences Quarterly
https://www.readbyqxmd.com/read/28811782/clinical-effects-of-pulmonary-surfactant-in-combination-with-nasal-continuous-positive-airway-pressure-therapy-on-neonatal-respiratory-distress-syndrome
#20
Congmin Zhang, Xiaojing Zhu
OBJECTIVE: To analyze the therapeutic effect of pulmonary surfactant (PS) in combination with nasal continuous positive airway pressure (NCPAP) therapy on neonatal respiratory distress syndrome (NRDS). METHODOLOGY: Forty-nine neonates who were diagnosed as NRDS and admitted in our hospital from May 2014 to June 2015 were selected and divided into an observation group and a control group. The observation group was treated with PS and NCPAP. The control group was treated only with NCPAP...
May 2017: Pakistan Journal of Medical Sciences Quarterly
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