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https://www.readbyqxmd.com/read/28732322/effects-of-environmental-pollutants-on-signaling-pathways-in-rat-pituitary-gh3-adenoma-cells
#1
Nicoletta Fortunati, Federica Guaraldi, Valentina Zunino, Federica Penner, Valentina D'Angelo, Francesco Zenga, Francesca Pecori Giraldi, Maria Graziella Catalano, Emanuela Arvat
An increased rate of acromegaly was reported in industrialized areas, suggesting an involvement of environmental pollutants in the pathogenesis and behavior of GH-secreting pituitary adenomas. Based on these premises, the aim of the study was to evaluate the effects of some widely diffused pollutants (i.e. benzene, BZ; bis(2-ethylhexyl) phthalate, DEHP and polychlorinated biphenyls, PCB) on growth hormone secretion, the somatostatin and estrogenic pathways, viability and proliferation of rat GH-producing pituitary adenoma (GH3) cells...
July 18, 2017: Environmental Research
https://www.readbyqxmd.com/read/28732133/ionization-and-collision-induced-dissociation-of-steroid-bis-glucuronides
#2
Argitxu Esquivel, Xavier Matabosch, Aristotelis Kotronoulas, Georgina Balcells, Jesús Joglar, Rosa Ventura
Studies on steroid metabolism are of utmost importance to improve the detection capabilities of anabolic androgenic steroids (AAS) misuse in sports drug testing. In humans, glucuronoconjugates are the most abundant phase II metabolites of AAS. Bis-glucuronidation is a reaction where two separated functional groups on the same molecule are conjugated with glucuronic acid. These metabolites have not been studied in depth for steroids and could be interesting markers for doping control. The aim of the present work was to study the ionization and collision induced dissociation of steroid bis-glucuronides to be able to develop mass spectrometric analytical strategies for their detection in urine samples after AAS administration...
July 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28731701/a-model-for-the-enantioselectivity-of-asymmetric-intramolecular-alkylations-by-bis-quaternized-cinchona-alkaloid-derived-catalysts
#3
Cyndi Qixin He, Adam Simon, Yu-Hong Lam, Andrew P J Brunskill, Nobuyoshi Yasuda, Jiajing Tan, Alan M Hyde, Edward C Sherer, Kendall N Houk
A model for the stereoselectivity of intramolecular alkylations by N,N'-disubstituted cinchona alkaloids reported by Xiang et al. was established using density functional theory (DFT) calculations. The stereocontrol is based on the minimal distortion of the TS and catalyst required to achieve favorable electrostatic interactions in the favored TS. Counterions must be included in computational modeling of ion-paired catalysis in order to reproduce experimental enantioselectivity.
July 21, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28731693/isolable-bis-triarylamine-dications-analogues-of-thiele-s-chichibabin-s-and-m%C3%A3-ller-s-hydrocarbons
#4
Gengwen Tan, Xinping Wang
Since the pioneering work by Thiele and Chichibabin, who synthesized the first diradicals bridged by phenylene and biphenylene groups in 1904 and 1907, respectively, numerous efforts have been devoted to synthesizing stable diradicals during the last few decades, and several strategies have been developed to stabilize these highly reactive diradicals. In this Account, we describe the synthesis and characterization of isolable bis(triarylamine) dications, nitrogen analogues of Thiele's, Chichibabin's, and Müller's hydrocarbons, which represent facilely accessible, stable diradicals by replacing carbinyl centers with isoelectronic aminium centers...
July 21, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28731587/reversible-pressure-controlled-depolymerization-of-a-copper-ii-containing-coordination-polymer
#5
Jack Kay Clegg, Aidan Brock, Katrina Jolliffe, Simon Parsons, Leonard Lindoy, Peter Tasker, Fraser White
A unique pressure-induced Cu-N bond breaking/bond forming reaction is reported. The variation of pressure on a single crystal of a one-dimensional copper(II)-containing coordination polymer (Cu2L2(1-methylpiperazine)2]n, where H2L is 1,1'-(1,3-phenylene)-bis(4,4-dimethylpentane-1,3-dione)), was monitored using single crystal X-ray diffraction with the aid of a diamond anvil cell. At a very low elevated pressure (~0.05 GPa) a remarkable reversible phase change was observed. The phase change results in the depolymerization of the material through the cleavage and formation of axial Cu-N bonds as well as "ring flips" of individual axially coordinated 1-methylpiperazine ligands...
July 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28731354/anionic-surfactants-on-anionic-substrate-monovalent-cation-binding
#6
Finian J Allen, Lucy Griffin, Richard M Alloway, Philipp Gutfreund, Seung Yeon Lee, Chris Leslie Truscott, Rebecca J L Welbourn, Mary H Wood, Stuart Matthew Clarke
Neutron reflectometry has been used to study the adsorption of the anionic surfactant bis(2-ethylhexyl) sulfosuccinate cesium salt (CsAOT) on the anionic surface of mica. Evidence of significant adsorption is reported. The adsorption is reversible and changes little with pH. This somewhat unexpected adsorption behaviour of an anionic molecule on an anionic surface is discussed in terms of recent models for surfactant adsorption such as cation bridging, where adsorption has been reported with the divalent ion calcium but not previously observed with monovalent ions...
July 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28731301/lead-ii-complexes-of-amino-acids-peptides-and-other-related-ligands-of-biological-interest
#7
Etelka Farkas, Péter Buglyó
Lead(II) forms (NH2,COO-)-chelated mono- and bis-complexes with simple amino acids, while mono-complexes with pH-dependent coordination modes exist with simple dipeptides. These mostly hemidirected complexes have moderate stability. While a weak interaction of side chain imidazole and carboxylate in lead(II)-aminoacidato complexes is found, the thiolate group has an exceptionally high affinity to this metal ion. For example, tridentate (NH2,COO-,S-)-coordination of penicillamine (Pen) and cysteine (Cys) results in an extremely strong interaction with lead(II), but, owing to the sterical effect of the 6s2 pair, a second ligand is not able to coordinate in the above mentioned tridentate way...
April 10, 2017: Metal Ions in Life Sciences
https://www.readbyqxmd.com/read/28730816/multi-functional-octamethyltetrasila-2-2-cyclophanes-conformational-variations-circularly-polarized-luminescence-and-organic-electroluminescence
#8
Masaki Shimada, Yoshinori Yamanoi, Tatsuhiko Ohto, Song-Toan Pham, Ryo Yamada, Hirokazu Tada, Kenichiro Omoto, Shohei Tashiro, Mitsuhiko Shionoya, Mineyuki Hattori, Keiko Jimura, Shigenobu Hayashi, Hikaru Koike, Munetaka Iwamura, Koichi Nozaki, Hiroshi Nishihara
Both symmetrical and unsymmetrical cyclophanes containing disilane units, tetrasila[2.2]cyclophanes 1-9, were synthesized. The syn and anti conformation and the kinetics of inversion between two anti-isomers were investigated by X-ray diffraction and variable-temperature NMR analysis, respectively. The flipping motion of two aromatic rings was affected by the bulkiness of the aromatic moiety (1 vs 6), the phase (solid vs solution), and the inclusion by host molecules (1 vs 1⊂[Ag2L](2)(+)). The photophysical, electrochemical, and structural properties of the compounds were thoroughly investigated...
July 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28730205/dithieno-3-2-b-2-3-d-pyrrole-benzo-c-1-2-5-thiadiazole-conjugate-small-molecule-donors-effect-of-fluorine-content-on-their-photovoltaic-properties
#9
Manohar Reddy Busireddy, Narendra Reddy Chereddy, Balaiah Shanigaram, Bhanuprakash Kotamarthi, Subhayan Biswas, Ganesh Datt Sharma, Jayathirtha Rao Vaidya
Two new small molecule donors, namely ICT4 and ICT6 with D1-A-D2-A-D1 architecture having 2,4-bis(2-ethylhexyl)-4H-dithieno[3,2-b:2',3'-d]pyrrole (EHDTP, D1) and 4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene (OBDT, D2) as the terminal and central donor, and benzo[c][1,2,5]thiadiazole (BT for ICT4) and 5,6-difluorobenzo[c][1,2,5]thiadiazole (F2BT for ICT6) as the acceptor (A) moieties, are synthesized and their optical, electronic and photovoltaic properties are investigated. Both ICT4 and ICT6 have considerable solubility in various solvents and possess efficient light absorption ability [ε (×10(5) mol(-1) cm(-1)) is 0...
July 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28729892/reversible-charge-trapping-in-bis-carbazole-diimide-redox-polymers-with-complete-luminescence-quenching-enabling-nondestructive-read-out-by-resonance-raman-spectroscopy
#10
Luuk Kortekaas, Federico Lancia, Jorn D Steen, Wesley R Browne
The coupling of substituted carbazole compounds through carbon-carbon bond formation upon one-electron oxidation is shown to be a highly versatile approach to the formation of redox polymer films. Although the polymerization of single carbazole units has been proposed earlier, we show that by tethering pairs of carbazoles double sequential dimerization allows for facile formation of redox polymer films with fine control over film thickness. We show that the design of the monomers and in particular the bridging units is key to polymer formation, with the diaminobenzene motif proving advantageous, in terms of the matching to the redox potentials of the monomer and polymer film and thereby avoiding limitations in film thickness (autoinsulation), but introduces unacceptable instability due to the intrinsic redox activity of this moiety...
July 13, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28729647/neural-determinants-of-human-goal-directed-vs-habitual-action-control-and-their-relation-to-trait-motivation
#11
Hamdi Eryilmaz, Anais Rodriguez-Thompson, Alexandra S Tanner, Madeline Giegold, Franklin C Huntington, Joshua L Roffman
Instrumental learning is mediated by goal-directed and habit systems in the brain. While rodent studies implicate distinct prefrontal/striatal regions in goal-directed and habit learning, neural systems underpinning these two processes in humans remain poorly understood. Here, using a validated discrimination learning task that distinguishes goal-directed learning from habit learning in 72 subjects in fMRI, we investigated the corticostriatal correlates of goal-directed learning and tested whether brain activation during learning is associated with trait motivation and behavioral performance in the post-learning test phase...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28728414/putting-a-new-spin-on-supramolecular-metallacycles-co3-triangle-and-co4-square-bearing-tetrazine-based-radicals-as-bridges
#12
Dimitris I Alexandropoulos, Brian S Dolinar, Kuduva R Vignesh, Kim R Dunbar
The synthesis of two new radical bridged compounds [Co3(bptz)3(dbm)3]∙2toluene (1) and [Co4(bptz)4(dbm)4]∙4MeCN (2) (bptz = 3,6-bis(pyridyl)-1,2,4,5-tetrazine; dbm = 1,3-diphenyl-1,3-propanedione) is reported. The presence of the ligand-centered radical has been confirmed by X-ray crystallography and SQUID magnetometry. These complexes are the first metallacycles bearing nitrogen heterocyclic radicals as bridges. Magnetic studies reveal strong antiferromagnetic metal···radical coupling with coupling constants of J = -67...
July 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28728108/new-tacrine-dimers-with-antioxidant-linkers-as-dual-drugs-anti-alzheimer-s-and-antiproliferative-agents
#13
Jesús M Roldán-Peña, Daniel Alejandre-Ramos, Óscar López, Inés Maya, Irene Lagunes, José M Padrón, Luis Emiliano Peña-Altamira, Manuela Bartolini, Barbara Monti, Maria L Bolognesi, José G Fernández-Bolaños
We have designed a series of tacrine-based homo- and heterodimers that incorporate an antioxidant tether (selenoureido, chalcogenide) as new dual compounds: for the treatment of Alzheimer's disease and as antiproliferative agents. Symmetrical homodimers bearing a dichalcogenide or selenide-based tether, the best compounds in the series, were found to be strong and highly selective electric eel AChE inhibitors, with inhibition constants within the low nanomolar range. This high inhibitory activity was confirmed on recombinant human AChE for the most interesting derivatives...
June 27, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28727440/sensitization-of-nanocrystalline-metal-oxides-with-a-phosphonate-functionalized-perylene-diimide-for-photoelectrochemical-water-oxidation-with-a-coo%C3%A2-catalyst
#14
Joel Thomas Kirner, Richard G Finke
A planar organic thin-film composed of a perylene diimide dye (N,N´-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoOx) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MOₓ) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO₂ > SnO₂ > WO₃...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28727018/evaluation-of-electrical-broad-bandwidth-impedance-spectroscopy-as-a-tool-for-body-composition-measurement-in-cows-in-comparison-with-body-measurements-and-the-deuterium-oxide-dilution-method
#15
C T Schäff, U Pliquett, A Tuchscherer, R Pfuhl, S Görs, C C Metges, H M Hammon, C Kröger-Koch
Body fatness and degree of body fat mobilization in cows vary enormously during their reproduction cycle and influence energy partitioning and metabolic adaptation. The objective of the study was to test bioelectrical impedance spectroscopy (BIS) as a method for predicting fat depot mass (FDM), in living cows. The FDM is defined as the sum of subcutaneous, omental, mesenteric, retroperitoneal, and carcass fat mass. Bioelectrical impedance spectroscopy is compared with the prediction of FDM from the deuterium oxide (DO) dilution method and from body conformation measurements...
May 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28726891/frontier-orbitals-of-photosubstitutionally-active-ruthenium-complexes-an-experimental-study-of-the-spectator-ligands-electronic-properties-influence-on-photoreactivity
#16
Hyo Jin Jang, Samantha L Hopkins, Maxime A Siegler, Sylvestre Bonnet
The synthesis and characterization of [Ru(tpy)(R2bpy)(L)](X)n complexes (tpy = 2,2':6',2''-terpyridine, R2bpy = 4,4'-dimethyl-2,2'-bipyridine (dmbpy), or 4,4'-bis(trifluoromethyl)-2,2'-bipyridine (tfmbpy), X = Cl(-) or PF6(-), and n = 1 or 2) are described. The dmbpy and tfmbpy bidentate ligands allow for investigating the effects of electron-donating and electron-withdrawing ligands, respectively, on the frontier orbital energetics as well as the photoreactivity of these ruthenium polypyridyl complexes for five prototypical monodentate ligands L = Cl(-), H2O, CH3CN, 2-(methylthio)ethanol (Hmte), or pyridine...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726673/off-on-fluorescence-monitoring-of-intracellular-ag-in-single-living-cells-using-an-ag-responsive-probe
#17
Jian Lv, Li-Jun Zhao, Ruo-Can Qian, Yi-Tao Long
Detection of silver ions (Ag+) in living cells has becoming more and more attractive due to the important biological impact of Ag+ on cellular functions. Here, we put forward a new approach to realize the in situ fluorescence imaging and detection of Ag+ in single cells via an ultrasensitive Ag+-responsive probe, 3', 6'-bis (diethylamino)-2-(2-iodoethyl) spiro[isoindoline-1, 9'-xanthen]-3-one (BDISIX). In the presence of Ag+, the fluorescence of the probe can be turned "on", generating strong red fluorescence...
July 20, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28726093/the-fluorescence-lifetime-of-lipofuscin-granule-fluorophores-contained-in-the-retinal-pigment-epithelium-cells-from-human-cadaver-eyes-in-normal-state-and-in-the-case-of-visualized-pathology
#18
M A Yakovleva, T B Feldman, P M Arbukhanova, S A Borzenok, V A Kuzmin, M A Ostrovsky
A comparative analysis of fluorescence lifetime of lipofuscin granule fluorophores contained in the retinal pigment epithelium cells from human cadaver eyes in normal state and in the case of visualized pathology was carried out. Measurements of fluorescence lifetimes of bis-retinoids and their photooxidation and photodegradation products were carried out using the method of counting time-correlated photons. Comparative analysis showed that, in the case of visualized pathology, the contribution of photooxidation and photodegradation products of bis-retinoids to the total fluorescence of the retinal pigment epithelium cell suspension increases in comparison with the norm...
May 2017: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28724198/direct-and-topoisomerase-ii-mediated-dna-damage-by-bis-3-chloropiperidines-the-importance-of-being-an-earnest-g
#19
Alice Sosic, Ivonne Zuravka, Nina-Katharina Schmitt, Angelica Miola, Richard Göttlich, Dan Fabris, Barbara Gatto
Bis-3-chloropiperidines are a new class of DNA-active compounds capable of alkylating nucleobases and inducing strand cleavage. In this report, we investigated the reactivity of these mustard-based agents with both single- and double-stranded DNA constructs. Polyacrylamide gel electrophoresis (PAGE) and electrospray ionization mass spectrometry (ESI-MS) were employed to obtain valuable insights into their mechanism at the molecular level and to investigate their time- and concentration-dependence. The results revealed the preferential formation of mono- and bifunctional adducts at nucleophilic guanine sites...
July 19, 2017: ChemMedChem
https://www.readbyqxmd.com/read/28723222/extraction-of-2-phenylethanol-pea-from-aqueous-solution-using-ionic-liquids-synthesis-phase-equilibrium-investigation-selectivity-in-separation-and-thermodynamic-models
#20
Urszula Maria Domanska, Patrycja Okuniewska, Kamil Paduszyński, Marta Królikowska, Maciej Zawadzki, Mikolaj Wieckowski
This work presents some important issues and topics related to possible extraction of 2-phenylethanol (PEA) from aqueous phase "in situ" during the biosynthesis. It consist of a series of experimental phase equilibrium measurements in binary and ternary systems. Ionic liquids (ILs) are an important new media for imaging and sensing applications because of their solvation property, thermal stability and negligible vapor pressure. However, complex procedures and non-miscibility with water are often required in PEA extraction...
July 19, 2017: Journal of Physical Chemistry. B
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