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Francesca Mastrogiuseppe, Srdjan Ostojic
Recurrent networks of non-linear units display a variety of dynamical regimes depending on the structure of their synaptic connectivity. A particularly remarkable phenomenon is the appearance of strongly fluctuating, chaotic activity in networks of deterministic, but randomly connected rate units. How this type of intrinsically generated fluctuations appears in more realistic networks of spiking neurons has been a long standing question. To ease the comparison between rate and spiking networks, recent works investigated the dynamical regimes of randomly-connected rate networks with segregated excitatory and inhibitory populations, and firing rates constrained to be positive...
April 24, 2017: PLoS Computational Biology
S Thamban, Arjun U, M Padmanabhan, Ramesh Chandra Nath
We present the synthesis and a detailed investigation of structural and magnetic properties of metal-organic compound Cu$_2$(IPA)$_2$(DMF)(H$_2$O) by means of x-ray diffraction, magnetization, and heat capacity measurements. Single crystals of the title compound were synthesized by judicious selection of organic ligand and employing a selective hydrothermal reaction route. It crystallizes in an orthorhombic structure with space group $Cmca$. The structural analysis revealed that two Cu$^{2+}$ ions are held together by the organic component (-O-C-O-) in a square paddle-wheel to form spin dimers which are aligned perpendicular to each other and are further coupled through organic ligands (isophthalic acid) forming two-dimensional layers...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Vinzenz Fleischer, Michaela Friedrich, Ayman Rezk, Ulrike Bühler, Esther Witsch, Timo Uphaus, Stefan Bittner, Sergiu Groppa, Björn Tackenberg, Amit Bar-Or, Frauke Zipp, Felix Luessi
BACKGROUND: The effect of dimethyl fumarate (DMF) on circulating lymphocyte subsets and their contribution as predictors of clinical efficacy have not yet been investigated in multiple sclerosis (MS). OBJECTIVE: To evaluate lymphocytes and lymphocyte subsets (analyzed 6 months after DMF start) in MS patients with and without disease activity after 1 year of treatment in a retrospective study. METHODS: Peripheral blood lymphocyte subsets were analyzed by flow cytometry...
April 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
Jing-Hui Zhang, Tai Sun, Aping Niu, Yu-Mei Tang, Shun Deng, Wei Luo, Qun Xu, Dapeng Wei, De-Sheng Pei
Graphene quantum dots (GQDs) has been widely used in enormous fields, however, the inherent molecular mechanism of GQDs for potential risks in biological system is still elusive to date. In this study, the outstanding reduced graphene quantum dots (rGOQDs) with the QY as high as 24.62% were successfully synthesized by the improved Hummers method and DMF hydrothermal treatment approach. The rGOQDs were N-doped photoluminescent nanomaterials with functional groups on the surface. The fluorescent bio-imaging was performed by exposing zebrafish in different concentrations of the as-prepared rGOQDs, and the distribution of rGOQDs was successfully observed...
April 15, 2017: Biomaterials
Payam Abdolalian, Ali Morsali, Giuseppe Bruno
Micro and nano-structures of a new mixed-ligand Zn(II) fumarate metal-organic polymer, {[Zn(tptz)(fum)].DMF}n (1), (tptz=2,4,6-tris(2-pyridyl)-s-triazine, fum=fumarate, DMF=N,N-dimethylforamide), were synthesized by sonochemical method. These new micro and nano-structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), IR spectroscopy and elemental analyses. Compound 1 was structurally characterized by single-crystal X-ray diffraction and consists of the primary unit of [Zn(tptz)(fum)]...
July 2017: Ultrasonics Sonochemistry
Sayed Ali Akbar Razavi, Mohammad Yaser Masoomi, Ali Morsali
TMU-34(-2H), [Zn(OBA)(DPT)0.5].DMF, has been sonochemically synthesized by applying H2OBA, (4,4'-oxybis(benzoic acid)), as the dicarboxylate linker, and DPT, (3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine), as pillar spacer. Sonication time, concentration of initial reagents, sonication power and molar ratio of pyridine as modulator has been optimized to synthesize nano powder of TMU-34(-2H) including uniform plate morphology. Nano TMU-34(-2H), can detect phenylhydrazine (PH) by color changing from pink to deep purple...
July 2017: Ultrasonics Sonochemistry
Fahime Bigdeli, Hosein Ghasempour, Alireza Azhdari Tehrani, Ali Morsali, Hassan Hosseini-Monfared
A 3D, porous Zn(II)-based metal-organic framework {[Zn2(oba)2(4-bpmn)]·(DMF)1.5}n (TMU-21), (4-bpmn=N,N'-Bis-pyridin-4-ylmethylene-naphtalene-1,5-diamine, H2oba=4,4'-oxybis(benzoic acid)) with nano-rods morphology under ultrasonic irradiation at ambient temperature and atmospheric pressure was prepared and characterized by scanning electron microscopy. Sonication time and concentration of initial reagents effects on the size and morphology of nano-structured MOFs were studied. Also {[Zn2(oba)2(4-bpmn)] (TMU-21) and {[Zn2(oba)2(4-bpmb)] (TMU-6), 4-bpmb=N,N'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) were easily prepared by mechanochemical synthesis...
July 2017: Ultrasonics Sonochemistry
Yuntong Zhai, Xiaofei Chen, Wei Zhou, Mengyang Fan, Yisheng Lai, Dawei Ma
Diaryl formation is achieved by coupling phenols and (hetero)aryl halides under the catalysis of CuI/N,N'-bis(2-phenylphenyl) oxalamide (BPPO) or CuI/ N-(2-phenylphenyl)-N'-benzyl oxalamide (PPBO) at 90 degrees C using DMF or MeCN as the solvent. Only 0.2-2 mol % CuI and ligand are required for completer conversion, which represents the lowest catalytic loadings for a general Cu/ligand-catalyzed diaryl ether formation.
April 21, 2017: Journal of Organic Chemistry
Andreas Konstantatos, Mikkel A Sørensen, Jesper Bendix, Høgni Weihe
Using a new polydentate Schiff-base ligand (H3L) we isolated three new tetranuclear isostructural lanthanide complexes with the general formula [LnNa2(L)4(DMF)4(H2O)2(AcO)2]·4DMF·2H2O [Ln = Dy (1), Ho (2), or Er (3)]. The structural characterization of the complexes reveals that the Na(+) ions are coordinated in the structure which gives them a structure-directing role in the molecule. The magnetic behavior of the systems was investigated by means of SQUID magnetometry which revealed that complex 1 exhibits single molecule magnet behavior at low temperatures which is enhanced by the application of a 2000 Oe static magnetic field...
April 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Georg Bieker, Julia Wellmann, Martin Kolek, Kirsi Jalkanen, Martin Winter, Peter Bieker
In order to gain a deeper understanding of Li and Mg polysulphides in Li/S and Mg/S batteries, respectively, this work investigates the impact of the two different cations as well as the influence of the electrolyte solvents' relative dielectric permittivity and Gutmann's donor number on the solubility and relative stability of different Li and Mg polysulphide species. Therefore, the disproportionation and dissociation equilibria of chemically prepared "Li2S8" and "MgS8" solutions in DMSO, DMF, ACN, THF, DME, TEGDME, and Pyr14TFSI are characterized by UV/Vis spectroscopy...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
Srinivasan Natarajan, Gargi Dutta, Ajay Kumar Jana
Three new metal-organic porphyrinic framework compounds of zinc and 5,10,15,20-tetrakis(4-pyridyl)porphyrin(TPyP) have been synthesized under solvothermal conditions. The compounds [Zn5(C40H24N8)(C8H4O4)2(NO3)6(DMA)2](DMA)3(H2O)8, 1; [Zn3(C40H24N8)(C8H4O4)2(DMF)](DMF)5(H2O)12, 2; and [Zn3(C40H24N8)(C12H6O4)2(DMA)2](H2O)7, 3 have two- (1) and three- dimensionally (2 and 3) extended structures. All the three structures contain porphyrinic unit connected through the carboxylate linkers. The nitrates binds the metal centers and not hydrogen bonded...
April 19, 2017: Chemistry: a European Journal
Yue-Ling Bai, Wei Du, Xiuping Yin, Jianhui Fang, Shourong Zhu, Jun Tao
A homochiral mixed-valence cobalt cluster [CoΙΙ16CoΙΙΙ4(μ6-O)4(μ3-OH)12(S-bme)12(OAc)6]Cl6·5CH3OH·18H2O (1, Hbme = 1H-(benzimidazol-2-yl)ethanol) was synthesized from a racemic ligand and three cobalt salts of CoCl2·6H2O, Co(Ac)2·4H2O and Co(NO3)2·6H2O in a DMF/MeOH mixed solvent. The enantioselective coordination occurs when a large excess of cobalt ions added in the solution and only the S-configuration of the racemic ligand involved in crystallization. The CD spectra of three crystal samples show identical Cotton signals, indicating the repeatability and the enantiomeric purity of the single crystals...
April 19, 2017: Chemistry: a European Journal
Iurie L Malaestean, Victor Ch Kravtsov, Janusz Lipkowski, Elena Cariati, Stefania Righetto, Daniele Marinotto, Alessandra Forni, Marina S Fonari
On the way to copper(I) iodide coordination polymers with specific luminescent properties, the in situ reduction of Cu(II) in the presence of KI and bidentate N-heteroatomic ligand, either pyrazine (pyz) or 4,4'-bipyridine (bpy), resulted in one two-dimensional and two three-dimensional new coordination networks. Starting from Cu(NO3)2·3H2O in the presence of pyz, successive precipitation of known yellow [(Cu(I)I)2(pyz)]n, new orange [Cu(I)I(pyz)]n, and new dark blue {[Cu(I)(pyz)2]·I5}n polymeric solids was observed...
April 18, 2017: Inorganic Chemistry
Mansoor Mandegari, Hossein Fashandi
Production of acrylonitrile-butadiene-styrene/polyurethane (ABS/PU) blend membrane with high rejection efficiency for disperse and vat dyes, is introduced as a facile and cost effective technique to purify textile wastewater. In this respect, membranes are produced using commercially available polymers, i.e. ABS and PU, with different compositions (ABS/PU: 100/0, 80/20, 70/30, 60/40 and 50/50 w/w) through wet casting. Casting solutions with concentration of 30 wt% are prepared using two different solvents, i...
April 13, 2017: Journal of Environmental Management
Chaoying Yang, Liang Gao, Jiaping Lin, Liquan Wang, Chunhua Cai, Yuhan Wei, Zhibo Li
Constructing polymeric toroids with a uniform, tunable size is challenging. Reported herein is the formation of uniform toroids from poly(γ-benzyl-l-glutamate)-graft-poly(ethylene glycol) (PBLG-g-PEG) graft copolymers by a two-step self-assembly process. In the first step, uniform rodlike micelles are prepared by dialyzing the polymer dissolved in tetrahydrofuran (THF)/N,N'-dimethylformamide (DMF) against water. With the addition of THF in the second step, the rodlike micelles curve and then close end-to-end to form uniform toroids, which resemble a cyclization reaction...
April 13, 2017: Angewandte Chemie
Sentayehu F Wondimu, Sebastian von der Ecken, Ralf Ahrens, Wolfgang Freude, Andreas E Guber, Christian Koos
We present a multi-sensor chip comprising an array of whispering-gallery mode (WGM) micro-goblet lasers integrated into a digital microfluidic (DMF) system. In contrast to earlier demonstrations, the lasers are fabricated from dye-doped poly-methyl methacrylate (PMMA) at low cost using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow techniques. Pumping and read-out of the devices is accomplished via simple free-space optics, thereby allowing large-scale sensor arrays to be addressed...
April 13, 2017: Lab on a Chip
Khatera Hazin, Spencer C Serin, Brian O Patrick, Maria B Ezhova, Derek P Gates
The development of solid, weighable Brønsted acids featuring the hexacoordinated phosphorous(v) anion [TRISPHAT](-) are reported. H(DMF)2[1] and H(THF)2[1] {[1](-) = [P(1,2-O2C6Cl4)3](-)} were synthesized and fully characterized by (1)H, (31)P, (13)C and 2D-NOESY NMR spectroscopy, X-ray crystallography, mass spectrometry and elemental analysis. Both, H(DMF)2[1] and H(THF)2[1] are found to be suitable initiators for the polymerization of n-butyl vinyl ether and p-methoxystyrene. Optimal polymerization results for these single-component initiators were generally obtained at -50 °C where high molecular weight polymers were isolated in high yield...
April 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiao-Yu Li, Hai-Feng Su, Mohamedally Kurmoo, Chen-Ho Tung, Di Sun, Lan-Sun Zheng
In view of elucidating potential structures and assembly mechanism of silver clusters and silver cluster-based metal-organic frameworks, we prepared four argento-organic-clusters/frameworks where the structures were directed by chromate in the presence of different thiolates. All four structures with (t)BuC6H4S(-), S(i)Bu(-), and S(i)Pr(-) consist of three core-shells, an inner CrO4(2-), an intermediate Ag-S aggregate and finally the protective organic moieties. {(HNEt3)3[Ag(CrO4)4@Ag46(SC6H4(t)Bu)24(CF3COO)18(DMF)4]} (1) is a supertetrahedron with an inner Ag(CrO4)4 tetrahedron shelled by four fused Ag11...
April 20, 2017: Nanoscale
Nicholas E Clay, Joseph J Whittenberg, Jiayu Leong, Vivek Kumar, Jinrong Chen, Insil Choi, Evangelos Liamas, Jeremy M Schieferstein, Jae Hyun Jeong, Dong Hyun Kim, Zhenyu Jason Zhang, Paul J A Kenis, Il Won Kim, Hyunjoon Kong
Recently, polymeric micelles self-assembled from amphiphilic polymers have been studied for various industrial and biomedical applications. This nanoparticle self-assembly typically occurs in a solvent-exchange process. In this process, the quality of the resulting particles is uncontrollably mediated by polymeric solubility and mixing conditions. Here, we hypothesized that improving the solubility of an amphiphilic polymer in an organic solvent via chemical modification while controlling the mixing rate of organic and aqueous phases would enhance control over particle morphology and size...
April 20, 2017: Nanoscale
Sourav Roy, Michael G B Drew, Antonio Bauzá, Antonio Frontera, Shouvik Chattopadhyay
Three new heteronuclear nickel(ii)/cadmium(ii) complexes, [(SCN)(Cl)Cd(L)Ni(DMF)2] (1), [(SCN)(CH3CO2)Cd(L)Ni(CH3OH)2] (2) and [(SCN)(Cl)Cd(L)Ni(NH2CH2CH2CH2NH2)]n (3) {where H2L = N,N'-bis(3-ethoxy-salicylidene)propane-1,3-diamine is a N2O4 compartmental Schiff base}, have been synthesized and characterized. The structures of the complexes have been confirmed by single crystal X-ray diffraction studies. In each complex, nickel(ii) is placed in the inner N2O2 environment and cadmium(ii) is placed in the outer O4 compartment of the compartmental Schiff base...
April 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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