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Brett A Duguay, Kate Wei-Chen Huang, Marianna Kulka
Mast cells are important immune cells that have significant roles in mediating allergy and asthma. Therefore, studying the molecular mechanisms regulating these and other processes in mast cells is important to elucidate. Methods such as lipofection, transduction, and electroporation are often employed to dissect these mechanisms by disrupting gene expression in mast cell lines. However, as with other leukocytes, human mast cells (HMCs) are often refractory to the delivery of plasmids by lipofection. In this study, we investigated the utility of lipid nanoparticles (LNPs) containing the ionizable cationic lipids 1,2-dioleoyloxy-3-dimethylaminopropane, 1,2-dioleyloxy-3-dimethylaminopropane, or 2,2-dilinoleyl-4-(2-dimethylaminoethyl)-[1,3]-dioxolane for the delivery of plasmid DNA into HMC lines...
April 18, 2018: Journal of Leukocyte Biology
Asha Brown, Thanthapatra Bunchuay, Christopher Crane, Nicholas White, Amber Thompson, Paul D Beer
A new bis-triazacyclononane tris-pyridyl N9-azacryptand ligand is synthesised via a convenient one-pot [2 + 3] condensation reaction between triazacyclononane and 2,6-bis(bromomethyl) pyridine in the presence of M2CO3 (M = Na, K). The proton, lithium, sodium, potassium and lead(II) complexes of the ligand are characterised in the solid state. A preliminary solution-phase competition experiment indicates that the cryptand ligand preferentially binds lead(II) in the presence of sodium, calcium, potassium and zinc cations in methanol solution...
April 18, 2018: Chemistry: a European Journal
José Manuel Vicent-Luna, Eneko Azaceta, Said Hamad, José Manuel Ortiz-Roldán, Ramón Tena-Zaera, Sofía Calero, Juan Antonio Anta
Among many other applications, room-temperature ionic liquids (ILs) are used as electrolytes for storage and energy-conversion devices. In this work, we investigate, at the microscopic level, the structural and dynamical properties of 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide [C4 PYR]+ [Tf2 N]- IL-based electrolytes for metal-ion batteries. We carried out molecular dynamics simulations of electrolytes mainly composed of [C4 PYR]+ [Tf2 N]- IL with the addition of Mn+ -[Tf2 N]- metal salts (M=Li+ , Na+ , Ni2+ , Zn2+ , Co2+ , Cd2+ , and Al3+ , n=1, 2, and 3) dissolved in the IL...
April 18, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Simon J Pope, Thomas Stonelake, Kaitlin Phillips, Simon Coles, Peter Horton, Shannon Keane, Emily Stokes, Ian Fallis, Joseph Beames, Jianzhang Zhao, Kepeng Chen, Yuqi Hou, Andrew Hallett, Sean O'Kell
A series of substituted 2-phenylquinoxaline ligands have been explored to finely tune the visible emission properties of a corresponding set of cationic, cyclometalated iridium(III) complexes. The electronic and redox properties of the complexes were investigated using experimental (including time-resolved luminescence and transient absorption spectroscopy) and theoretical methods. The complexes display absorption and phosphorescent emission in the visible region attributed to MLCT transitions. The different substitution patterns of the ligands induce variations in these parameters...
April 18, 2018: Chemistry: a European Journal
Richard Burkett Dewell, Fabrizio Gabbiani
Collision avoidance is critical for survival, including in humans, and many species possess visual neurons exquisitely sensitive to objects approaching on a collision course. Here, we demonstrate that a collision-detecting neuron can detect the spatial coherence of a simulated impending object, thereby carrying out a computation akin to object segmentation critical for proper escape behavior. At the cellular level, object segmentation relies on a precise selection of the spatiotemporal pattern of synaptic inputs by dendritic membrane potential-activated channels...
April 18, 2018: ELife
Xiuxia Zhao, Shaowei Zhang, Junqing Yan, Landong Li, Guangjun Wu, Wei Shi, Guangming Yang, Naijia Guan, Peng Cheng
Two stable 3D polyoxometalate-based metal-organic frameworks (PMOFs), [CuI 12 (trz)8 (H2 O)2 ][α-SiW12 O40 ]·2H2 O (1) and [CuI 12 (trz)8 Cl][α-PW12 O40 ] (2) (Htrz = 1- H-1,2,4-triazole) based on Keggin-type POMs were successfully obtained and fully characterized. The basic building units of the two PMOFs are [CuI 12 (trz)8 ], but polyoxoanion (POA) template effect leads to different structures and properties: 1 represents an interesting example that [α-SiW12 O40 ]4- locate in the nine-membered Cu-trz rings through Cu···O weak interactions to form a 3D framework, whereas 2 shows a 3D structure constructed from 2D bilayer cationic network [CuI 12 (trz)8 Cl]3+ and [α-PW12 O40 ]3- lying in the adjacent layers via Cu···O weak interactions...
April 18, 2018: Inorganic Chemistry
Hui Yang, Siobhan J Bradley, Xin Wu, Andrew Chan, Geoffrey I N Waterhouse, Thomas Nann, Jian Zhang, Paul E Kruger, Shengqian Ma, Shane G Telfer
Nanoparticles comprising three or more different metals are challenging to prepare. General methods that tackle this challenge are highly sought after as multicomponent metal nanoparticles display favorable properties in applications such as catalysis, biomedicine, and imaging. Herein, we report a practical and versatile approach for the synthesis of nanoparticles composed of up to four different metals. This method relies on the thermal decomposition of nanostructured composite materials assembled from platinum nanoparticles, a metal-organic framework (ZIF-8), and a tannic acid coordination polymer...
April 18, 2018: ACS Nano
Jing Xie, Harrison A Neal, Jennifer Szymanowski, Peter C Burns, Todd M Alam, May Nyman, Laura Gagliardi
We obtained a kerosene-soluble form of the lithium salt [UO2 (O2 )(OH)2 ]24 phase (Li-U24 ), by adding cetyltrimethylammonium bromide surfactant to aqueous Li-U24 . Interestingly, its variable-temperature solution 7 Li NMR spectroscopy resolves two narrowly spaced resonances down to -10 °C, which shift upfield with increasing temperature, and finally coalesce at temperatures > 85 °C. Comparison with solid-state NMR demonstrates that the Li dynamics in the Li-U24 -CTA phase involves only exchange between different local encapsulated environments...
April 18, 2018: Inorganic Chemistry
Hiromitsu Maeda, Yuka Takeda, Yohei Haketa, Yuta Morimoto, Nobuhiro Yasuda
π-Extended nitro-substituted dipyrrolylphenol derivatives were synthesized, providing π-electronic anions upon deprotonation and stabilization of the phenolate (phenoxide) moiety by the pyrrole NH, which served as a hydrogen-bonding donor. Ion-pairing assemblies of the deprotonated anions were formed in the solid state and as mesophases. In the solid state, the extended π-plane is more suitable to form charge-by-charge assemblies in combination with tetraalkylammonium cations with highly anisotropic orientations through its more efficient stacking...
April 18, 2018: Chemistry: a European Journal
Heejune Park, Giovanni Meloni
In this study, interactions between the superalkali species Li3F2 and four volatile organic compounds (VOCs), methanol, ethanol, formaldehyde, and acetaldehyde, are assessed using the CBS-QB3 composite model. Adiabatic ionization energy (AIE), adiabatic electron affinity (AEA), binding energy (BE), charge transfer (∆q), and highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO-LUMO) gaps have been computed. Stronger interactions are observed between Li3F2 and the aldehydes than alcohols...
April 18, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Bohuslav Drahoš, Zdeněk Trávníček
A cross-bridged cyclam derivative containing two 2-pyridylmethyl pendant arms (L = 4,11-bis((pyridin-2-yl)methyl)-1,4,8,11-tetraaza-bicyclo[6.6.2]hexadecane) was synthesized by dialkylation of the cross-bridged cyclam with 2-chloromethylpyridine. A series of Fe(ii) complexes with L and different counter-anions of the formulas [Fe(L)][FeCl4]·H2O (1·H2O), [Fe(L)]Cl2·4H2O (2·4H2O), [Fe(L)](BF4)2·0.5CH3CN (3·0.5CH3CN) and [Fe(L)](BPh4)2·CH3OH (4·CH3OH) was prepared and thoroughly characterized. In all the cases, the [Fe(L)]2+ cation adopts a cis-V configuration with a distorted octahedral geometry, and with the FeN6 donor set...
April 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Stefan K Kolev, Petko St Petkov, Miroslav A Rangelov, Dimitar V Trifonov, Teodor I Milenov, Georgi N Vayssilov
Alkaline and alkaline earth ions, namely Na+, K+, Mg2+ and Ca2+, are critical for the stability, proper folding and functioning of RNA. Moreover, those metal ions help to facilitate macromolecular interactions as well as the formation of supramolecular structures (e.g. the ribosome and the ribozymes). Therefore, identifying the interactions between ions and nucleic acids is a key to the better comprehension of the physical nature and biological functions of those biomolecules. The scope of this review is to highlight the preferential location and binding sites of alkaline and alkaline earth metal ions compensating the negatively charged backbone of nucleic acids and interacting with other electronegative centers, focusing on RNA...
April 18, 2018: Metallomics: Integrated Biometal Science
Diana Rafael, Petra Gener, Fernanda Andrade, Joaquin Seras-Franzoso, Sara Montero, Yolanda Fernández, Manuel Hidalgo, Diego Arango, Joan Sayós, Helena F Florindo, Ibane Abasolo, Simó Schwartz, Mafalda Videira
Development of RNA interference-based therapies with appropriate therapeutic window remains a challenge for advanced cancers. Because cancer stem cells (CSC) are responsible of sustaining the metastatic spread of the disease to distal organs and the progressive gain of resistance of advanced cancers, new anticancer therapies should be validated specifically for this subpopulation of cells. A new amphihilic-based gene delivery system that combines Pluronic® F127 micelles with polyplexes spontaneously formed by electrostatic interaction between anionic siRNA and cationic polyethylenimine (PEI) 10K, was designed (PM)...
November 2018: Drug Delivery
Tingting Jiang, Michael E Hoover, Matthew V Holt, Michael A Freitas, Alan G Marshall, Nicolas L Young
Post-translational modifications (PTMs) of histones are important epigenetic regulatory mechanisms that are often dysregulated in cancer. We employ middle-down proteomics to investigate the PTMs and proteoforms of histone H4 during cell cycle progression. We use pH gradient weak cation exchange-hydrophilic interaction liquid chromatography (WCX-HILIC) for on-line liquid chromatography-mass spectrometry analysis to separate and analyze the proteoforms of histone H4. This provides enhanced separation of proteoforms, including positional isomers, and simplifies downstream data analysis...
April 17, 2018: Proteomics
Atsuhiro Osuka, Koki Kise, Yongseok Hong, Norihito Fukui, Daiki Shimizu, Dongho Kim
Diarylamine-fused subporphyrins 1a and 1b were synthesized from β,β-diiodo-meso-chloro subporphyrin 2 via one-pot procedure involving nucleophilic aromatic substitution and SRN1-type intramolecular fusion reaction as the first example of meso-nitrogen-embedded subporphyrin. While non-fused counterparts 3b and 3b display effective fluorescence quenching due to TICT in CH2Cl2 at room temperature, 1b emits fluorescence with ΦF = 0.18 under the same conditions, because conformational twisting is not allowed due to the fused structure...
April 17, 2018: Chemistry: a European Journal
Reza Nickmanesh, Rachel C Stewart, Brian D Snyder, Mark W Grinstaff, Bassam A Masri, David R Wilson
Contrast-enhanced computed tomography (CECT) using charged contrast-agents enables quantification of cartilage glycosaminoglycan content. Since glycosaminoglycan content is a key determinant of cartilage compressive stiffness, CECT measurements have the potential to non-invasively assess cartilage stiffness. The objective of this study was to determine whether CECT attenuation, using a cationic contrast-agent (CA4 +), correlates with the stiffness of intact cartilage. Six fresh femoral and six fresh tibial compartments with intact cartilage were obtained from patients undergoing total knee replacement surgery...
April 17, 2018: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Erik Schneider, Katrina Brendle, Patrick Jäger, Patrick Weis, Manfred M Kappes
We present gas-phase structures of dimers of MnIII and FeIII meso-tetra(4-sulfonatophenyl)porphyrin multianions with various amounts of sodium and hydrogen counterions. The structural assignments are achieved by combining mass spectrometry, ion mobility measurements, quantum chemical calculations, and trajectory method collision cross section calculations. For a common charge state, we observe significant topological variations in the dimer structures of [(MTPPS)2 +nX](6-n)- (M=MnIII , FeIII ; X=H, Na; n = 1-3) induced by replacing hydrogen counterions by sodium...
April 17, 2018: Journal of the American Society for Mass Spectrometry
Maria-Gabriela Alexandru, Diana Visinescu, Sergiu Shova, Willian X C Oliveira, Francesc Lloret, Miguel Julve
A new series of {FeIII2LnIII2} heterobimetallic squares of general formula [FeIII{HB(pz)3}(CN)(μ-CN)2Ln(pyim)x(NO3)2(H2O)y]2·zH2O [Ln = La (1), Gd (2), Tb (3) and Dy (4); {HB(pz)3}- = hydrotris(pyrazolyl)borate and pyim = 2-(1H-imidazol-2-yl)pyridine; x = 2, y = 0 (1), x = y = 1 (2-4) and z = 10 (1), 6 (2), 2.76 (3), 4 (4)] were synthesized by reacting the low-spin [FeIII{HB(pz)3}(CN)3]- complex anion with the preformed [LnIII(pyim)x(NO3)2(H2O)y]+ complex cation [formed in situ by mixing the lanthanide(iii) salt and the pyim ligand]...
April 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Ana-Maria Chiorcea-Paquim, Ramon Eritja, Ana Maria Oliveira-Brett
Guanine-rich DNA sequences are able to form G-quadruplexes, being involved in important biological processes and representing smart self-assembling nanomaterials that are increasingly used in DNA nanotechnology and biosensor technology. G-quadruplex electrochemical biosensors have received particular attention, since the electrochemical response is particularly sensitive to the DNA structural changes from single-stranded, double-stranded, or hairpin into a G-quadruplex configuration. Furthermore, the development of an increased number of G-quadruplex aptamers that combine the G-quadruplex stiffness and self-assembling versatility with the aptamer high specificity of binding to a variety of molecular targets allowed the construction of biosensors with increased selectivity and sensitivity...
2018: Journal of Nucleic Acids
Weiqiong Ma, Qi Xie, Baolin Zhang, Huixian Chen, Jianyi Tang, Zhengxian Lei, Minyi Wu, Dingxuan Zhang, Jiani Hu
Magnetic resonance imaging (MRI) combined with contrast agents is believed to be useful for stem cell tracking in vivo, and the aim of this research was to investigate the biosafety and neural induction of SD rat-originated adipose derived stem cells (ADSCs) using cationic superparamagnetic iron oxide (SPIO) nanoparticle which was synthesized by the improved polyol method, in order to allow visualization using in vitro MRI. The scan protocols were performed with T2-mapping sequence; meanwhile, the ultrastructure of labeled cells was observed by transmission electron microscopy (TEM) while the iron content was measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES)...
2018: Contrast Media & Molecular Imaging
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