keyword
MENU ▼
Read by QxMD icon Read
search

EPR

keyword
https://www.readbyqxmd.com/read/28212040/synthesis-and-speciation-dependent-properties-of-a-multimetallic-model-complex-of-nisod-that-exhibits-unique-hydrogen-bonding
#1
Ramsey A Steiner, Stephen P Dzul, Timothy L Stemmler, Todd C Harrop
The complex Na3[{Ni(II)(nmp)}3S3BTA(alk))] (1) (nmp(2-) = deprotonated form of N-(2-mercaptoethyl)picolinamide; H3S3BTA(alk) = N(1),N(3),N(5)-tris(2-mercaptoethyl)benzene-1,3,5-tricarboxamide, where H = dissociable protons), supported by the thiolate-benzenetricarboxamide scaffold (S3BTA(alk)), has been synthesized as a trimetallic model of nickel-containing superoxide dismutase (NiSOD). X-ray absorption spectroscopy (XAS) and (1)H NMR measurements on 1 indicate that the Ni(II) centers are square-planar with N2S2 coordination, and Ni-N and Ni-S distances of 1...
February 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28211967/generation-of-the-scf3-radical-by-photoredox-catalysis-intra-and-intermolecular-carbotrifluoromethylthiolation-of-alkenes
#2
Guillaume Dagousset, Cédric Simon, Elsa Anselmi, Béatrice Tuccio, Thierry Billard, Emmanuel Magnier
We report herein the first use of N-trifluoromethylthiosaccharin as the source of SCF3 radical under photoredox catalysis. This allowed an efficient and general visible-light-mediated carbotrifluoromethylthiolation of alkenes. Under the optimized conditions using fac-Ir(ppy)3 as the photocatalyst, various N-aryl acrylamides as well as a wide range of substituted styrenes can readily be difunctionalized in an intra- or intermolecular fashion, affording the corresponding SCF3-containing products in good to excellent yield...
February 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28211204/evaluation-of-the-enhanced-permeability-and-retention-effect-in-the-early-stages-of-lymph-node-metastasis
#3
Mamoru Mikada, Ariunbuyan Sukhbaatar, Yoshinobu Miura, Sachiko Horie, Maya Sakamoto, Shiro Mori, Tetsuya Kodama
Most solid cancers spread to new sites via the lymphatics before hematogenous dissemination. However, only a small fraction of an intravenously administered anti-cancer drug enters the lymphatic system to reach metastatic lymph nodes (LNs). Here, we show that the enhanced permeability and retention (EPR) effect is not induced during the early stages of LN metastasis. Luciferase-expressing tumor cells were injected into the subiliac LN of the MXH10/Mo-lpr/lpr mouse to induce metastasis to the proper axillary LN (PALN)...
February 17, 2017: Cancer Science
https://www.readbyqxmd.com/read/28210984/effect-of-solution-ionic-strength-on-the-pka-of-the-nitroxide-ph-epr-probe-2-2-3-4-5-5-hexamethylimidazolidin-1-oxyl
#4
Kaleigh Margita, Maxim A Voinov, Alex I Smirnov
Spin probe and spin labeling Electron Paramagnetic Resonance methods are indispensable research tools for solving a wide range of bioanalytical problems-from measuring microviscosity and polarity of phase-separated liquids to oxygen concentrations in tissues. One of the emerging uses of spin probes are the studies of proton transfer-related and surface electrostatic phenomena. The latter Electron Paramagnetic Resonance methods rely on molecular probes containing an additional functionality capable of reversible ionization (protonation, in particular) in the immediate proximity to an Electron Paramagnetic Resonance-active reporter group, such as (N-O(•)) for nitroxides...
February 17, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28210718/synthesis-and-epr-spectroscopic-characterization-of-the-perchlorotriarylmethyl-tricarboxylic-acid-radical-ptmtc-and-its-13-c-labelled-analogue-13c-ptmtc
#5
Marwa Elewa, Nadica Maltar-Strmečki, Mohamed M Said, Hosam A El Shihawy, Mohamed El-Sadek, Juliane Frank, Simon Drescher, Malte Drescher, Karsten Mäder, Dariush Hinderberger, Peter Imming
A hydrophilic tris(tetrachlorotriaryl)methyl (tetrachloro-TAM) radical labelled 50% with (13)C at the central carbon atom was prepared. The mixture of isotopologue radicals was characterised by continuous wave and pulsed X-band electron paramagnetic spectroscopy (EPS). For the pharmaceutical and medical applications planned, the quantitative influence of oxygen, viscosity, temperature and pH on EPR line widths was studied in aqueous buffer, DMSO, water-methanol and water-glycerol mixtures. Under in vivo conditions, pH can be disregarded...
February 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28208774/cytotoxicity-and-antioxidant-potential-of-novel-2-2-1h-indol-5yl-methylene-hydrazinyl-thiazole-derivatives
#6
Adriana Grozav, Ioan-Dan Porumb, Luiza Ioana Găină, Lorena Filip, Daniela Hanganu
Newly synthesized 2-(2-((1H-indol-5yl)methylene)-hydrazinyl)-thiazole derivatives were evaluated for their in vitro cytotoxicity on two carcinoma cell lines A2780 and HeLa. Significant cytotoxic activity for 2-(2-((1H-indol-5-yl)methylene)hydrazinyl)-4-methylthiazole (1) and 2-(2-((1H-indol-5-yl)methylene)hydrazinyl)-4-phenylthiazole (3), on both A2780 [IC50: 11.6 μM (1), and 12.4 μM (3)] and HeLa [IC50: 22.4 μM (1) and 19.4μM (3)] cell lines is reported. Their antioxidant potential was evaluated by spectrophotometric method, using DPPH radical or Fe (TPTZ)(3+) complex, and EPR spectroscopy, therefore the compounds 1 and 3 showed remarkable antioxidant activity simultaneously with a cytotoxic effect on A2780 and HeLa cell lines...
February 9, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28208266/link-between-affinity-and-cu-ii-binding-sites-to-amyloid-%C3%AE-peptides-evaluated-by-a-new-water-soluble-uv-visible-ratiometric-dye-with-a-moderate-cu-ii-affinity
#7
Amandine Conte-Daban, Valentina Borghesani, Stéphanie Sayen, Emmanuel Guillon, Yves Journaux, Geoffrey Gontard, Laurent Lisnard, Christelle Hureau
Being able to easily determine the Cu(II) affinity for biomolecules of moderate affinity is important. Such biomolecules include amyloidogenic peptides, such as the well-known amyloid-β peptide involved in Alzheimer's disease. Here, we report the synthesis of a new water-soluble ratiometric Cu(II) dye with a moderate affinity (10(9) M(-1) at pH 7.1) and the characterizations of the Cu(II) corresponding complex by X-ray crystallography, EPR, and XAS spectroscopic methods. UV-vis competition was performed on the Aβ peptide as well as on a wide series of modified peptides, leading to an affinity value of 1...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28207252/metal-metal-bridging-using-the-dppp-dye-system-electronic-configurations-within-multiple-redox-series
#8
Arijit Singha Hazari, Abhishek Mandal, Katharina Beyer, Alexa Paretzki, Wolfgang Kaim, Goutam Kumar Lahiri
Redox series [LnRu(μ-DPPP)RuLn](k), H2DPPP = 2,5-dihydro-3,6-di-2-pyridylpyrrolo(3,4-c)pyrrole-1,4-dione and L = 2,4-pentanedionato (acac(-)), 2,2'-bipyridine (bpy), and 2-phenylazopyridine (pap), have been studied by voltammetry (CV, DPV), EPR, and UV-vis-NIR spectroelectrochemistry, supported by TD-DFT calculations. Crystal structure analysis and (1)H NMR revealed oxidation states [(acac)2Ru(III)(μ-DPPP(2-))Ru(III)(acac)2] and [(bpy)2Ru(II)(μ-DPPP(2-))Ru(II)(bpy)2](2+) for the corresponding precursors, isolated as rac diastereomers...
February 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28205420/tetrabutylammonium-salts-of-aluminum-iii-and-gallium-iii-phthalocyanine-radical-anions-bonded-with-fluoren-9-olato%C3%AF-anions-and-indium-iii-bromide-phthalocyanine-radical-anions
#9
Dmitri Konarev, Salavat Khasanov, Manabu Ishikawa, Yoshiaki Nakano, Akihiro Otsuka, Hideki Yamochi, Gunzi Saito, Rimma N Lyubovskaya
Reduction of aluminum(III), gallium(III) and indium(III) chloride phthalocyanines by sodium fluorenone ketyl in the presence of tetrabutylammonium cations yielded crystalline salts (Bu4N+)2[M(III)(HFl-O-)(Pc*3-)](*-)(Br-).1.5C6H4Cl2 (M = Al (1), Ga(2), HFl-O- = Fluoren-9-olato- anion) and (Bu4N+)[In(III)Br(Pc*3-)]*-.0.875C6H4Cl2.0.125C6H14 (3). The salts contain Pc(*3-) radical anions with negatively charged phthalocyanine macrocycles evidenced by the presence of intense bands of (Pc*3-) in the NIR range and noticeable blue shift of both Q- and Soret bands of phthalocyanine...
February 15, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28202542/m%C3%A3-ssbauer-spectra-of-mouse-hearts-reveal-age-dependent-changes-in-mitochondrial-and-ferritin-iron-levels
#10
Joshua D Wofford, Mrinmoy Chakrabarti, Paul Alan Lindahl
Cardiac function requires continuous high levels of energy, and so iron, a critical player in mitochondrial respiration, is an important component of the heart. Hearts from (57)Fe-enriched mice were evaluated by Mossbauer spectroscopy. Spectra consisted of a sextet and two quadrupole doublets. One doublet was due to residual blood while the other was due to [Fe4S4](2+) clusters and Fe(II) hemes, most of which were associated with mitochondrial respiration. The sextet was due to ferritin; there was no evidence of hemosiderin, a ferritin decomposition product...
February 15, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28199865/non-photochemical-production-of-singlet-oxygen-via-activation-of-persulfate-by-carbon-nanotubes
#11
Xin Cheng, Hongguang Guo, Yongli Zhang, Xiao Wu, Yang Liu
The reaction between persulfate (PS) and carbon nanotubes (CNTs) for the degradation of 2,4-dichlorophenol (2,4-DCP) was investigated. It was demonstrated that CNTs could efficiently activate PS for the degradation of 2,4-DCP. Results suggested that the neither hydroxyl radical (OH) nor sulfate radical (SO4(-)) was produced therein. For the first time, the generation of singlet oxygen ((1)O2) was proved by several methods including electron paramagnetic resonance spectrometry (EPR) and liquid chromatography mass spectrometry measurements...
February 8, 2017: Water Research
https://www.readbyqxmd.com/read/28198492/redox-state-manipulation-of-a-tris-p-tetrazolylphenyl-amine-ligand-and-its-mn-2-coordination-frameworks
#12
Carol Hua, Jing-Yuan Ge, Floriana Tuna, David Collison, Jing-Lin Zuo, Deanna M D'Alessandro
In situ spectroelectrochemical experiments coupled with UV/Vis/NIR, EPR, magnetism and fluorescence techniques have enabled insights into the electronic properties of the tris(p-tetrazolylphenyl)amine (H3TTPA) ligand and the new Mn(2+) frameworks [Mn3(TTPA)2(MeOH)6]n (1) and [Mn3(TTPA)2(DMF)6]n (2). Oxidation of H3TTPA generated the triarylamine radical which was found to be delocalised throughout the ligand backbone. Solid state Vis/NIR and EPR spectroelectrochemical experiments on the frameworks were used to probe the optical properties of the accessible redox states and their relative stabilities, as well as the charge transfer interactions which were generated upon infiltration of electron acceptor guests...
February 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28198148/stimuli-responsive-liposomes-for-drug-delivery
#13
REVIEW
Y Lee, D H Thompson
The ultimate goal of drug delivery is to increase the bioavailability and reduce the toxic side effects of the active pharmaceutical ingredient (API) by releasing them at a specific site of action. In the case of antitumor therapy, association of the therapeutic agent with a carrier system can minimize damage to healthy, nontarget tissues, while limit systemic release and promoting long circulation to enhance uptake at the cancerous site due to the enhanced permeation and retention effect (EPR). Stimuli-responsive systems have become a promising way to deliver and release payloads in a site-selective manner...
February 15, 2017: Wiley Interdisciplinary Reviews. Nanomedicine and Nanobiotechnology
https://www.readbyqxmd.com/read/28195741/behavior-of-ppi-g2-dendrimer-in-a-microemulsion
#14
Shifra Rokach, Maria Francesca Ottaviani, Alexander I Shames, Abraham Aserin, Nissim Garti
Dendrimer nanostructures are of eminent interest in biomedical applications because of their uniform and well-defined molecular size and shape, and their ability to cross cell membranes and reduce the risk of premature clearance from the human body. Dendrimers perform as gene and drug carriers and have also shown significant therapeutic properties for treating cancer and neurodegenerative diseases. A complex drug delivery system, based on a dendrimer solubilized in the aqueous core of a water-in-oil (W/O) microemulsion (ME) along with the drug may combine the advantages of both dendrimers and MEs to provide better control of drug release...
February 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28195462/molecular-and-electronic-structures-of-eight-coordinate-uranium-bipyridine-complexes-a-rare-example-of-a-bipy-2-ligand-coordinated-to-a-u-4-ion
#15
Michael W Rosenzweig, Frank W Heinemann, Laurent Maron, Karsten Meyer
Reaction of trivalent [(((Ad,tBu)ArO)3tacn)U] (1) with 2,2'-bipyridine (bipy) yields [(((Ad,tBu)ArO)3tacn)U(bipy)] (2) and subsequent reduction of 2 with KC8 in the presence of Kryptofix222 furnishes [K(2.2.2-crypt)][(((Ad,tBu)ArO)3tacn)U(bipy)] (3). Alternatively, complex 3 can be synthesized from 1 by addition of [K(bipy)] in the presence of the cryptand. New complexes 2 and 3 are characterized by a variety of spectroscopic, electrochemical, and magnetochemical methods, single-crystal X-ray diffraction, computational methods, and CHN elemental analysis...
February 14, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28194969/spin-frustration-in-the-triradical-trianion-of-a-naphthalenediimide-molecular-triangle
#16
Yilei Wu, Matthew D Krzyaniak, J Fraser Stoddart, Michael R Wasielewski
Crystalline supramolecular frameworks consisting of charged molecules, held together by hydrogen bonds and Coulomb interactions, have attracted great interest because of their unusual structural, chemical, electronic and magnetic properties. Herein, we report the preparation, structure and magnetic properties of the triradical trianion of a shape-persistent chiral equilateral molecular triangle having three naphthalene-1,4:5,8-bis(dicarboximide)s ((+)-NDI-(Δ3(-•))). Single-crystal X-ray diffraction of its tris(cobaltocenium) salt ([(+)-NDI--(Δ3(-•))(CoCp2(+))(3)]) reveals accessible one-dimensional tubular cavities, and variable-temperature electron paramagnetic resonance (EPR) spectroscopy shows that a dilute solution of [(+)-NDI--(Δ3(-•))(CoCp2(+))(3)] in an organic glass has a spin-frustrated doublet ground state and a thermally accessible quartet state...
February 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28194458/an-assessment-of-hydrocarbon-species-in-the-methanol-to-hydrocarbon-reaction-over-a-zsm-5-catalyst
#17
Suwardiyanto, Russell F Howe, Emma K Gibson, C Richard A Catlow, Ali Hameed, James McGregor, Paul Collier, Stewart F Parker, David Lennon
A ZSM-5 catalyst is examined in relation to the methanol-to-hydrocarbon (MTH) reaction as a function of reaction temperature and time-on-stream. The reaction profile is characterised using in-line mass spectrometry. Furthermore, the material contained within a catch-pot downstream from the reactor is analysed using gas chromatography-mass spectrometry. For a fixed methanol feed, reaction conditions are selected to define various stages of the reaction coordinate: (i) initial methanol adsorption at a sub-optimum reaction temperature (1 h at 200 °C); (ii) initial stages of reaction at an optimised reaction temperature (1 h at 350 °C); (iii) steady-state operation at an optimised reaction temperature (3 days at 350 °C); and (iv) accelerated ageing (3 days at 400 °C)...
February 14, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28192155/modality-of-tumor-endothelial-vegfr2-silencing-mediated-improvement-in-intratumoral-distribution-of-lipid-nanoparticles
#18
Shoshiro Yamamoto, Akari Kato, Yu Sakurai, Tomoya Hada, Hideyoshi Harashima
The vascular endothelial growth factor (VEGF)-mediated enhancement in vascular permeability is considered to be a major factor in tumor-targeting delivery via the enhanced permeability and retention (EPR) effect. We previously reported that the silencing of the endothelial VEGF receptor (VEGFR2) by a liposomal siRNA system (RGD-MEND) resulted in an enhanced intratumoral distribution of polyethylene glycol (PEG)-modified liposomes (LPs) in a renal cell carcinoma, a type of hypervascularized cancer, although the inhibition of VEGF signaling would be expected to decrease the permeability of the tumor vasculature...
February 10, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28191964/understanding-and-curing-structural-defects-in-colloidal-gaas-nanocrystals
#19
Vishwas Srivastava, Wenyong Liu, Eric M Janke, Vladislav Kamysbayev, Alexander S Filatov, Chengjun Sun, Byeongdu Lee, Tijana Rajh, Richard D Schaller, Dmitri V Talapin
GaAs is one of the most important semiconductors. However, colloidal GaAs nanocrystals remain largely unexplored because of the difficulties with their synthesis. Traditional synthetic routes either fail to produce pure GaAs phase or result in materials whose optical properties are very different from the behavior expected for quantum dots of direct-gap semiconductors. In this work, we demonstrate a variety of synthetic routes toward crystalline GaAs NCs. By using a combination of Raman, EXAFS, transient absorption, and EPR spectroscopies, we conclude that unusual optical properties of colloidal GaAs NCs can be related to the presence of Ga vacancies and lattice disorder...
February 13, 2017: Nano Letters
https://www.readbyqxmd.com/read/28191934/electronic-structure-of-corrole-derivatives-insights-from-molecular-structures-spectroscopy-electrochemistry-and-quantum-chemical-calculations
#20
Abhik Ghosh
Presented herein is a comprehensive account of the electronic structure of corrole derivatives. Our knowledge in this area derives from a broad range of methods, including UV-vis-NIR absorption and MCD spectroscopies, single-crystal X-ray structure determination, vibrational spectroscopy, NMR and EPR spectroscopies, electrochemistry, X-ray absorption spectroscopy, and quantum chemical calculations, the latter including both density functional theory and ab initio multiconfigurational methods. The review is organized according to the Periodic Table, describing free-base and main-group element corrole derivatives, then transition-metal corroles, and finally f-block element corroles...
February 13, 2017: Chemical Reviews
keyword
keyword
94905
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"