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Lei Cao, Jintang Guo, Jianhua Tian, Yang Xu, Miaomiao Hu, Chun Guo, Meiyu Wang, Jinjie Fan
Synthetic polymer fluid loss additive (FLA), an important type of admixture, was broadly applied in modern well cementation. However, the filter loss volume and fluidity of cement pastes containing polymer-FLA would deteriorate remarkably when sea water was used in mixing slurries instead of fresh water. In this study, a novel sustained-release-type fluid loss additive(S-FLA) was synthesized by means of anion-exchange intercalation reaction between an anionic type-copolymer and a calcium/aluminum type-Layered Double Hydroxide (Ca/Al-LDH)...
April 4, 2018: Journal of Colloid and Interface Science
Archana Khosa, Satish Reddi, Ranendra N Saha
Nanostructured lipid carriers (NLC), comprises of a blend of solid and liquid lipids which results in a partially crystallized lipid system and imparts many advantages over solid lipid nanoparticles such as enhanced drug loading capacity, drug release modulation flexibility and improved stability. NLC have found numerous applications in both pharmaceutical and cosmetic industry due to ease of preparation, the feasibility of scale-up, biocompatibility, non-toxicity, enhanced targeting efficiency and the possibility of site-specific delivery via various routes of administration...
April 17, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Ikuro Abe, Takayoshi Awakawa, Takahiro Mori, Yu Nakashima, Rui Zhai, Chin Piow Wong, Matthew Hillwig, Xinyu Liu
AmbP1 is a cyanobacterial aromatic prenyltransferase and a dedicated synthase for (R)-3-geranyl-3-isocyanovinyl indolenine (2), the biogenetic precursor for hapalindole-type alkaloids. The regioselective geranylation of cis-indolyl vinyl isonitrile (1) by the standalone AmbP1 to give 2 has been shown to require magnesium ion (Mg2+) to suppress the formation of cis-2-geranylindolyl vinyl isonitrile (3). Here, we report the high-resolution crystal structures of AmbP1 in complex with 1 and geranyl S-thiodiphosphate (GSPP) in the presence and absence of Mg2+ effector...
April 20, 2018: Angewandte Chemie
Orsolya Gyulai, Anita Kovács, Tamás Sovány, Ildikó Csóka, Zoltán Aigner
This research work presents the use of the Quality by Design (QbD) concept for optimization of the spherical agglomeration crystallization method in the case of the active agent, ambroxol hydrochloride (AMB HCl). AMB HCl spherical crystals were formulated by the spherical agglomeration method, which was applied as an antisolvent technique. Spherical crystals have good flowing properties, which makes the direct compression tableting method applicable. This means that the amount of additives used can be reduced and smaller tablets can be formed...
April 20, 2018: Materials
Song Zhang, Jiajia Liu, Karla Hernandez Ruiz, Rong Tu, Meijun Yang, Qizhong Li, Ji Shi, Haiwen Li, Lianmeng Zhang, Takashi Goto
In this study, we demonstrated the chemical vapor deposition (CVD) of vertically standing molybdenum disulfide (MoS₂) nanosheets, with an unconventional combination of molybdenum hexacarbonyl (Mo(CO)₆) and 1,2-ethanedithiol (C₂H₆S₂) as the novel kind of Mo and S precursors respectively. The effect of the distance between the precursor’s outlet and substrates (denoted as d ) on the growth characteristics of MoS₂, including surface morphology and nanosheet structure, was investigated. Meanwhile, the relationship between the structure characteristics of MoS₂ nanosheets and their catalytic performance for hydrogen evolution reaction (HER) was elucidated...
April 20, 2018: Materials
Jianbin Zheng, Long Chen, Owen S Skinner, Daniel Ysselstein, Jonathan Remis, Peter Lansbury, Renato Skerlj, Michael Mrosek, Ursula Heunisch, Stephan Krapp, Joel Charrow, Michael Schwake, Neil L Kelleher, Richard B Silverman, Dimitri Krainc
β-Glucocerebrosidase (GCase) mutations cause Gaucher's disease and are a high risk factor in Parkinson's disease. The implementation of a small molecule modulator is a strategy to restore proper folding and lysosome delivery of degradation-prone mutant GCase. Here, we present a potent quinazoline modulator, JZ-4109, which stabilizes wild-type and N370S mutant GCase and increases GCase abundance in patient-derived fibroblast cells. We then developed a covalent modification strategy using a lysine targeted inactivator (JZ-5029) for in vitro mechanistic studies...
April 20, 2018: Journal of the American Chemical Society
Nian-Tzu Suen, Sheng-Ping Guo, James Hoos, Svilen Bobev
Reported are the syntheses, crystal structures, and electronic structures of six rare-earth metal-lithium stannides with the general formulas RE3 Li4- x Sn4+ x (RE = La-Nd, Sm) and Eu7 Li8- x Sn10+ x . These new ternary compounds have been synthesized by high-temperature reactions of the corresponding elements. Their crystal structures have been established using single-crystal X-ray diffraction methods. The RE3 Li4- x Sn4+ x phases crystallize in the orthorhombic body-centered space group Immm (No. 71) with the Zr3 Cu4 Si4 structure type (Pearson code oI22), and the Eu7 Li8- x Sn10+ x phase crystallizes in the orthorhombic base-centered space group Cmmm (No...
April 20, 2018: Inorganic Chemistry
Elena Meirzadeh, Isabelle Weissbuch, David Ehre, Meir Lahav, Igor Lubomirsky
Crystals are physical arrays delineated by polar surfaces and often contain imperfections of a polar nature. Understanding the structure of such defects on the molecular level is of topical importance since they strongly affect the macroscopic properties of materials. Moreover, polar imperfections in crystals can be created intentionally and specifically designed by doping nonpolar crystals with "tailor-made" additives as dopants, since their incorporation generally takes place in a polar mode. Insertion of dopants also induces a polar deformation of neighboring host molecules, resulting in the creation of polar domains within the crystals...
April 20, 2018: Accounts of Chemical Research
Xianghe Meng, Fei Liang, Mingjun Xia, Zheshuai Lin
Two gallium-based borates, K3 Ba3 Li2 Ga4 B6 O20 F (I) and Rb3 Ba3 Li2 Ga4 B6 O20 F (II), have been successfully grown in the M2 O (M = K, Rb)-LiF-B2 O3 flux. They can be recognized as the element cosubstitutions of Sr for K/Rb and Ba and of Be for Li and Ga from Sr2 Be2 (BO3 )2 O (SBBO), which uses poisonous beryllium oxide during the synthesis and crystal growth process and also exhibits the problem of structural instability. The isostructural borates crystallize into the noncentrosymmetric space group P6̅2 c, with a = 8...
April 20, 2018: Inorganic Chemistry
Jun Wang, Jinlei Li, Jiani Yu, Hongwu Zhang, Bingbo Zhang
Persistent luminous nanoparticles (PLNPs) have been capturing increasing attention in biomedical imaging because of their long-life emission and concomitant benefits (e.g., zero-autofluorescence background, high signal-to-noise ratio). Although there are quite some synthetic methodologies to synthesize PLNPs, those for constructing functional structured PLNPs remain largely unexplored. Herein we report the design principle, synthesis route, and proof-of-concept applications of hollow structured PLNPs with near-infrared (NIR) persistent luminescence, namely afterglow, and tunable sizes for tumor afterglow imaging and chemical/photodynamic therapies...
April 20, 2018: ACS Nano
Akira Miura, Masanori Nagao, Yosuke Goto, Yoshikazu Mizuguchi, Tatsuma D Matsuda, Yuji Aoki, Chikako Moriyoshi, Yoshihiro Kuroiwa, Yoshihiko Takano, Satoshi Watauchi, Isao Tanaka, Nataly Carolina Rosero-Navarro, Kiyoharu Tadanaga
Ce1- x Pr x OBiS2 powders and Ce0.5 Pr0.5 OBiS2 single crystals were synthesized and their structure and superconductive properties were examined by X-ray diffraction, X-ray absorption, electronic resistivity, and magnetization. While PrOBiS2 was found to be in a monoclinic phase with one-dimensional Bi-S zigzag chains showing no superconductive transition above 0.1 K, CeOBiS2 was in a tetragonal phase with two-dimensional Bi-S planes showing zero resistivity below 1.3 K. In the range x = 0.3-0.9 in Ce1- x Pr x OBiS2 , both monoclinic and tetragonal phases were formed together with zero resistivity up to a maximum temperature of 2...
April 20, 2018: Inorganic Chemistry
Fabian Spitzer, Gabor Balazs, Christian Graßl, Martin Keilwerth, Karsten Meyer, Manfred Scheer
A first systematic study of the activation of As4 by Co complexes is presented. Three different low-valent [LCo(tol)] (L = β-diiminato) complexes reveal different steric influences as well as the electronic influence of their adjacent substituents. Dipp (2,6-diisopropylphenyl) and dmp (2,6-dimethylphenyl) flanking groups were applied, one of the ligands with H backbone substituents (β-dialdiminate L0) and two with Me substituents (β-diketiminates L3 and L1). In the reaction with As4, different dinuclear products [(LCo)2As4] (LM = L0 (1), L1 (2), L3 (3)) were isolated, each of them representing an individually shaped [Co2As4] core in the solid state: octahedral in 1, prismatic in 2 and asterane-like in 3...
April 20, 2018: Angewandte Chemie
Szymon Sobczak, Wojciech Drożdż, Giulio Lampronti, Anna Belenguer, Andrzej Katrusiak, Artur Ryszard Stefankiewicz
We describe here for the first time the application of combined pressure and temperature stimuli in disulfide metathesis reactions. In the system studied, above a pressure of 0.2 GPa equimolar amounts of symmetric disulfides bis 4-chlorophenyl disulfide [(4-ClPhS)2] and bis 2-nitrophenyl disulfide [(2-NO2PhS)2] react to give the heterodimeric product 4-ClPhSSPh2-NO2. In contrast to experiments conducted in solution at atmospheric pressure or in mechanochemical experiments under ball-mill grinding conditions, there is no necessity to use a base or thiolate anion as a catalyst for the exchange reaction under investigated conditions...
April 20, 2018: Chemistry: a European Journal
Wei Liu, Qun Xu
Localized surface plasmon resonances (LSPRs) of ultra-thin two-dimensional (2D) nanomaterials opened a new regime in plasmonics in the last several years. 2D plasmonic materials are yet concentrated on the crystal structure, amorphous materials are hardly reported because of their limited preparation methods rather than undesired plasmonic properties. Taking molybdenum oxides as an example, herein, we elaborate the 2D amorphous plasmons prepared with the assistance of supercritical CO2. In brief, we examine the reported characteristic plasmonic properties of molybdenum oxides, and applications of supercritical CO2 in formations of 2D layer materials as well as introduced phase and disorder engineering based on our researchs...
April 20, 2018: Chemistry: a European Journal
Matthias Tamm, Tobias Schnabel, Daniel Melcher, Kai Brandhorst, Dirk Bockfeld
Complex [PhCΞW{OSi(OtBu)3}3] (1) catalyzed the cross-metathesis between 1,4-bis(trimethylsilyl)-1,3-butadiyne (2) and symmetrical 1,3-diynes (3) efficiently, which gave access to TMS-capped 1,3-diynes RCΞC-CΞCSiMe3 (4). Diyne cross-metathesis (DYCM) studies with 13C-labeled diyne PhCΞ13C-13CΞCPh (3*) revealed that this reaction proceeds through reversible carbon-carbon triple-bond cleavage and formation according to the conventional mechanism of alkyne metathesis. The reaction between 1 and 3* afforded the complex PhCΞ13C-13CΞW{OSi(OtBu)3}3] (5*), indicating that alkynylalkylidyne complexes are likely to act as catalytically active species...
April 20, 2018: Chemistry: a European Journal
Wei Wang, Xing Tang, Fang Hua, Tie-Jun Ling, Xiao-Chun Wan, Guan-Hu Bao
Three new dimeric imidazole alkaloids with a methylene bridge, camellimidazole A-C (1-3), were isolated from Keemum black tea. Their structures were completely elucidated by a combination of diverse spectroscopic and single-crystal X-ray diffraction analyses. The plausible formation pathway of camellimidazole A-C was proposed. Compounds 1 and 2 exhibited remarkable protection against H2 O2 -induced neuronal damage at the concentration of 1.0 μM.
April 20, 2018: Organic Letters
Tamil Selvan Natarajan, Shigeru Okamoto, Klaus Werner Stöckelhuber, Sven Wiessner, Uta Reuter, Dieter Fischer, Anik Ghosh, Gert Heinrich, Amit Das
A mechanically adaptable elastomer composite is prepared with reversible soft-stiff properties that can be easily controlled. By the exploitation of different morphological structures of calcium sulphate, which is acting as active filler in soft elastomer matrix, the magnitude of filler reinforcement can be reversibly altered that will be reflected in changes of the final stiffness of the material. The higher stiffness, in other words, the higher modulus of the composites, is realized by the in-situ development of fine nano-structured calcium sulphate di-hydrate crystals, which are formed during exposure to water and, further, this highly reinforcing crystals can be transformed to a non-reinforcing hemi-hydrate mesocrystalline structure by simply heating the system in a controlled way...
April 20, 2018: ACS Applied Materials & Interfaces
Jitendra Pal Singh, Baljeet Kaur, Aditya Sharma, So Hee Kim, Sanjeev Gautam, Ramesh Chandra Srivastava, Navdeep Goyal, Weol Cheol Lim, H-J Lin, J M Chen, K Asokan, D Kanjilal, Sung Ok Won, Ik-Jae Lee, Keun Hwa Chae
The interactions of energetic ions with multi-cation compounds and their consequences in terms of changes in the local electronic structure, which may facilitate intriguing hybridization between O 2p and metal d orbitals and magnetic ordering, are the subject of debate and require a deep understanding of energy transfer processes and magnetic exchange mechanisms. In this study, nanocrystals of ZnFe2O4 were exposed to O7+ ions with an energy of 100 MeV to understand, qualitatively and quantitatively, the metal-ligand field interactions, cation migration and magnetic exchange interactions by employing X-ray absorption fine structure measurements and X-ray magnetic circular dichroism to get deeper mechanistic insights...
April 20, 2018: Physical Chemistry Chemical Physics: PCCP
Xiaoming Zhao, Tianjun Liu, Yuzhou Cui, Xueyan Hou, Zilu Liu, Xingyi Dai, Jie Kong, Wenda Shi, T John S Dennis
There are only a few reported methods by which the size and morphology of organic single crystals for high-performance organic field-effect transistors (OFETs) or other devices can be controlled. Here, a facile solution-processed antisolvent vapor diffusion method was employed to grow millimeter-length C60 single crystal microwires directly in solution. The size of the microwires can be controllably varied via the C60 concentration and/or the choice of antisolvent. OFETs fabricated from the as-produced microwires exhibit mobilities as high as 2...
April 20, 2018: Nanoscale
Seema Sharma, Ram Nawal Rao, Krushna Chandra Pani, Paramita Paul
Systemic oxalosis can be either primary or secondary hyperoxaluria. Oxalosis is a phenomenon in which calcium oxalate crystals deposit in various visceral organs leading to bone marrow (BM) failure and recurrent renal stones. We describe two rare cases of BM oxalosis. Hyperoxaluria is strongly associated with nephrolithiasis and nephrocalcinosis. Both the patients presented with recurrent renal stones and a variable degree of BM failure. BM oxalosis should be considered as a possible diagnosis in patients in recurrent nephrolithiasis and cytopenia...
April 2018: Indian Journal of Pathology & Microbiology
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