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https://www.readbyqxmd.com/read/29035522/cobalt-ion-promoted-redox-cascade-a-route-to-spiro-oxazine-oxazepine-derivatives-and-a-dinuclear-cobalt-iii-complex-of-an-n-1-4-naphthoquinone-o-aminophenol-derivative
#1
Sandip Mondal, Sachinath Bera, Suvendu Maity, Prasanta Ghosh
The study discloses that the redox activity of N-(1,4-naphthoquinone)-o-aminophenol derivatives (L(R)H2) containing a (phenol)-NH-(1,4-naphthoquinone) fragment is notably different from that of a (phenol)-NH-(phenol) precursor. The former is a platform for a redox cascade. L(R)H2 is redox noninnocent and exists in Cat-N-(1,4-naphthoquinone)(2-) (L(R 2-)) and SQ-N-(1,4-naphthoquinone) (L(R •-)) states in the complexes. Reactions of L(R)H2 with cobalt(II) salts in MeOH in air promote a cascade affording spiro oxazine-oxazepine derivatives ((OX)L(R)) in good yields, when R = H, Me, (t)Bu...
October 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29033177/arsenic-phosphorus-interactions-in-the-soil-plant-microbe-system-dynamics-of-uptake-suppression-and-toxicity-to-plants
#2
Hossain M Anawar, Zed Rengel, Paul Damon, Mark Tibbett
High arsenic (As) concentrations in the soil, water and plant systems can pose a direct health risk to humans and ecosystems. Phosphate (Pi) ions strongly influence As availability in soil, its uptake and toxicity to plants. Better understanding of As(V)-Pi interactions in soils and plants will facilitate a potential remediation strategy for As contaminated soils, reducing As uptake by crop plants and toxicity to human populations via manipulation of soil Pi content. However, the As(V)-Pi interactions in soil-plant systems are complex, leading to contradictory findings among different studies...
October 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29031252/reorientation-induced-spectral-diffusion-of-non-isotropic-orientation-distributions
#3
Zhe Ren, Sean Garrett-Roe
When reorientation of a vibrational chromophore is faster than the relaxation of its local environment, the frequency fluctuation correlation function (FFCF) measured by two-dimensional infrared spectroscopy (2D-IR) spectroscopy is an interplay of scalar structural spectral diffusion and vectorial reorientation-induced spectral diffusion (RISD). Theory has been established to calculate the RISD component of different polarization configurations with the assumption that the molecule orients randomly in a local electric field...
October 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29031247/extracting-spectroscopic-molecular-parameters-from-short-pulse-photo-electron-angular-distributions
#4
R Chamakhi, R Puthumpally-Joseph, M Telmini, E Charron
Using a quantum wave packet simulation including the nuclear and electronic degrees of freedom, we investigate the femtosecond and picosecond energy- and angle-resolved photoelectron spectra of the E(Σg+1) electronic state of Li2. We find that the angular distributions of the emitted photoelectrons depend strongly on the pulse duration in the regime of ultrashort laser pulses. This effect is illustrated by the extraction of a time-dependent asymmetry parameter whose variation with pulse duration can be explained by an incoherent average over different ion rotational quantum numbers...
October 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29028384/effect-of-metal-surfaces-on-matrix-assisted-laser-desorption-ionization-analyte-peak-intensities
#5
Vidhyullatha Kancharla, Sajid Bashir, Jingbo L Liu, Oscar M Ramirez, Peter J Derrick, Kyle A Beran
Different metal surfaces in the form of transmission electron microscope grids were examined as support surfaces in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with a view towards enhancement of peptide signal intensity. The observed enhancement between 5-fold and 20-fold relative to the normal stainless steel slide was investigated by applying the thermal desorption model for matrix-assisted laser desorption/ionization. A simple model evaluates the impact that the thermal properties of the metals have on the ion yield of the analyte...
October 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/29027934/angiotensin-i-converting-enzyme-ace-inhibitory-activity-antioxidant-properties-phenolic-content-and-amino-acid-profiles-of-fucus-spiralis-l-protein-hydrolysate-fractions
#6
Lisete Paiva, Elisabete Lima, Ana Isabel Neto, José Baptista
Food protein-derived hydrolysates with multi-bioactivities such as antihypertensive and antioxidant properties have recently received special attention since both activities can play significant roles in preventing cardiovascular diseases. This study reports, for the first time, the angiotensin I-converting enzyme (ACE)-inhibition and antioxidant properties of ultrafiltrate fractions (UF) with different molecular weight ranges (<1, 1-3 and ≥3 kDa) obtained from Fucus spiralis protein hydrolysate (FSPH) digested with cellulase-bromelain...
October 13, 2017: Marine Drugs
https://www.readbyqxmd.com/read/29027561/influence-of-temperature-gradients-on-charge-transport-in-asymmetric-nanochannels
#7
Anne M Benneker, Hans David Wendt, Rob G H Lammertink, Jeffery A Wood
Charge selective asymmetric nanochannels are used for a variety of applications, such as nanofluidic sensing devices and energy conversion applications. In this paper, we numerically investigate the influence of an applied temperature difference over tapered nanochannels on the resulting charge transport and flow behavior. Using a temperature-dependent formulation of the coupled Poisson-Nernst-Planck and Navier-Stokes equations, various nanochannel geometries are investigated. Temperature has a large influence on the total ion transport, as the diffusivity of ions and viscosity of the solution are strongly affected by temperature...
October 13, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29026151/synthesis-and-absorption-properties-of-hollow-spherical-dy2cu2o5-via-a-coordination-compound-method-with-dycu-3-4-pdc-2-oac-h2o-2-%C3%A2-10-5h2o-precursor
#8
Xuanwen Liu, Junhua You, Renchao Wang, Zhiyuan Ni, Fei Han, Lei Jin, Zhiqi Ye, Zhao Fang, Rui Guo
Dy2Cu2O5 nanoparticles with perovskite structures were synthesized via a simple solution method (SSM) and a coordination compound method (CCM) using [DyCu(3,4-pdc)2(OAc)(H2O)2]•10.5H2O (pdc = 3,4-pyridinedicarboxylic acid) as precursor. The as-prepared samples were structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS) and standard Brunauer-Emmett-Teller (BET) methods. Compared to the aggregated hexahedral particles prepared by SSM, the Dy2Cu2O5 of CCM showed hollow spherical morphology composed of nanoparticles with average diameters of 100-150 nm and a larger special surface area up to 36...
October 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29025657/novel-fluoridated-silk-fibroin-tio2-nanocomposite-scaffolds-for-bone-tissue-engineering
#9
Narges Johari, Hamid Reza Madaah Hosseini, Ali Samadikuchaksaraei
It is known that Fluoride ions strongly affect bone mineralization and formation. In the present study, the engineered bone tissue scaffolds are fabricated using silk fibroin (SF) and flouridated TiO2 nanoparticles. TiO2 nanoparticles are modified by fluoride ions, and different levels (0, 5, 10, 15 and 20wt%) of the fluoridated TiO2 nanoparticles (TiO2-F) were subsequently added to the SF matrix through phase separation method to prepare silk fibroin/flouridated TiO2 nanocomposite scaffolds (SF/TiO2-F). Phase structure, functional groups, morphology and mechanical properties of the obtained scaffolds were evaluated by X-ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and compressive testing, respectively...
January 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/29022974/the-mechanism-of-cesium-ions-immobilization-in-the-nanometer-channel-of-calcium-silicate-hydrate-a-molecular-dynamics-study
#10
Jinyang Jiang, Pan Wang, Dongshuai Hou
The cement-based matrices are preferred candidates in disposing nuclear waste due to the immobilization role of the calcium-silicate-hydrate (C-S-H) gel. To better understand the immobilization mechanism of cementitious materials, molecular dynamics was utilized to investigate the intensity distribution, local structure and dynamics properties of Cs(+) ions in the vicinity of the calcium silicate surface. The strong inner-sphere adsorbed cesium ions were restricted by coordinated oxygen atoms in bridging and pair silicate tetrahedron and water molecules were fixed in the silicate channel by H-bonds network...
October 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29022343/synthesis-and-crystal-structure-of-li-fluoreno-60-fullerene-effect-of-encapsulated-lithium-ion-on-electrochemistry-of-spiroannelated-fullerene
#11
Hiroshi Ueno, Hiroshi Okada, Shinobu Aoyagi, Yutaka Matsuo
The reaction of [Li+@C60]TFSI- (TFSI = bis(trifluoromethanesulfonyl)imide) with 9-diazofluorene directly produced a [6,6]-adduct of lithium-ion-containing fluoreno[60]fullerene, [6,6]-[Li+@C60(fluoreno)]TFSI-. X-ray structure analysis revealed the spiro-fullerene structure of fluoreno[60]fullerene and unusual localization of the encapsulated Li+ at three different positions. Cyclic voltammetry of the compound showed a reversible one-electron reduction wave at -0.51 V (vs Fc/Fc+) and an irreversible reduction wave for the second electron...
October 12, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29019037/role-of-sulfate-chloride-and-nitrate-anions-on-the-degradation-of-fluoroquinolone-antibiotics-by-photoelectro-fenton
#12
Paola Villegas-Guzman, Florian Hofer, Javier Silva-Agredo, Ricardo A Torres-Palma
Taking ciprofloxacin (CIP) as a fluoroquinolone antibiotic model, this work explores the role of common anions (sulfate, nitrate, and chloride) during the application of photoelectro-Fenton (PEF) at natural pH to degrade this type of compound in water. The system was composed of an IrO2 anode, Ti, or gas diffusion electrode (GDE) as cathode, Fe(2+), and UV (254 nm). To determine the implications of these anions, the degradation pathway and efficiency of the PEF sub-processes (UV photolysis, anodic oxidation, and electro-Fenton at natural pH) were studied in the individual presence of the anions...
October 10, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29016141/an-x-ray-and-neutron-reflectivity-study-shows-clic1-undergoes-cholesterol-dependant-structural-re-organisation-in-lipid-monolayers
#13
Khondker Rufaka Hossain, Stephen Andrew Holt, Anton P Le Brun, Heba Al Khamici, Stella M Valenzuela
CLIC1 belongs to the ubiquitous family of Chloride Intracellular Ion Channel proteins that are evolutionarily conserved across species. The CLICs are unusual in that they exist mainly as soluble proteins but possess the intriguing property of spontaneous conversion from the soluble to an integral membrane-bound form. This conversion is regulated by the membrane lipid composition especially cholesterol together with external factors such as oxidation and pH. However, the precise physiological mechanism regulating CLIC1 membrane insertion is currently unknown...
October 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28994233/large-continuous-mechanical-gradient-formation-via-metal-ligand-interactions
#14
James A Neal, Nathan J Oldenhuis, Emil Samson, Andrea L Novitsky, William J Thrift, Regina Ragan, Zhibin Nm Guan
Mechanical gradients are often employed in nature to prevent damage from large forces by creating a smooth transition from strong to weak biological materials. Synthetic mimics of these natural structures are highly desired to improve distribution of stresses at interfaces and reduce contact deformation in manmade materials. Current synthetic gradient materials commonly suffer from non-continuous transitions, relatively small gradients in mechanical properties, and difficult syntheses. Inspired by the polychaete worm jaw, we report a novel approach to generate stiffness gradients in polymeric materials via incorporation of monodentate, dynamic metal-ligand crosslinks...
October 9, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28990530/isoform-separation-by-a-mixed-mode-resin-toyopearl-mx-trp-650m
#15
Tsutomu Arakawa
TOYOPEARL particles are cross-linked hydroxylated methacrylic polymers available in different pore and particle sizes. They are conjugated with different ligands to generate ion-exchange, hydrophobic interaction and affinity resins. They have excellent physical and chemical properties. A mixed-mode resin, TOYOPEARL MX-Trp-650M, is made of this particle with tryptophan conjugated via N-terminal amino group and hence has both hydrophobic/aromatic side chain and carboxyl group. In this review, I will summarize the properties of the TOYOPEARL particles and MX-Trp-650M resin and application of this resin for purification of proteins and in some detail the separation of disulfide (SS)-scrambled oligomers of insulin-like growth factor-1 (IGF-1)...
October 9, 2017: Current Protein & Peptide Science
https://www.readbyqxmd.com/read/28989032/system-map-for-the-ionic-liquid-stationary-phase-tri-tripropylphosphoniumhexanamido-triethylamine-bis-trifluoromethylsulfonyl-imide-for-gas-chromatography
#16
Nicole Lenca, Colin F Poole
The solvation parameter model is used to construct a system map for the retention of volatile organic compounds on the ionic liquid stationary phase tri(tripropypphosphoniumhexanamido)triethylamine bis(trifluoromethylsulfonyl)imide (SLB-IL76) over the temperature range 80-240°C. The SLB-IL76 stationary phase is moderately cohesive and strongly dipolar/polarizable and hydrogen-bond basic but only a weak hydrogen-bond acid. Electron lone pair interactions are weak and make only a minor contribution to the retention mechanism...
September 28, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28986473/mouse-red-blood-cell-mediated-rare-xenobiotic-phosphorylation-of-a-drug-molecule-not-intended-to-be-a-kinase-substrate
#17
Chungang Gu, Shenghua Wen, Peter Doig, Eric Gangl, Xiaolan Zheng, Yanjun Wang, Jeffrey W Johannes
Phosphorylation of xenobiotics is rare, probably due to a strong evolutionary pressure against it. This rarity may have attracted more attention recently, owing to intentionally designed kinase-substrate analogs which depend on kinase-catalyzed activation to form phosphorylated active drugs. We report a rare phosphorylated metabolite observed unexpectedly in mouse plasma samples after an oral dose of a Tankyrase inhibitor that was not intended to be a kinase substrate, i.e. (S)-2-(4-(6-(3,4-dimethylpiperazin-1-yl)-4-methylpyridin-3-yl)phenyl)-8-(hydroxymethyl)quinazolin-4(3H)-one (AZ2381)...
October 6, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28985904/facile-preparation-of-multi-functionalized-hybrid-monoliths-via-two-step-photo-initiated-reactions-for-two-dimensional-liquid-chromatography-mass-spectrometry
#18
Haiyang Zhang, Shujuan Ma, Yating Yao, Yanan Li, Ya Li, Junjie Ou, Mingliang Ye, Yinmao Wei
A facile approach was developed to prepare hybrid monoliths with different functions via two-step photo-initiated reactions. Firstly, acrylopropyl polyhedral oligomertic silsesquioxane (acryl-POSS) and propargyl acrylate (PA) were used as precursors to synthesize alkynyl-functionalized hybrid monoliths via photo-initiated free radical polymerization. Secondly, the hybrid monoliths were modified with 1-octadecanethiol (ODT) and sodium 3-mercapto-1-propanesulfonate (SMPS) via photo-initiated thiol-yne click reaction to prepare reversed-phase (RP) and strong cation-exchange (SCX) hybrid monoliths, respectively...
September 28, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28985870/polymeric-micelles-loaded-with-1-2-diaminocyclohexane-platinum-ii-against-colorectal-cancer
#19
Takako Nirei, Soichiro Ishihara, Toshiaki Tanaka, Tomomichi Kiyomatsu, Kazushige Kawai, Keisuke Hata, Hioaki Nozawa, Toshiaki Watanabe
BACKGROUND: We investigated the potential of nanomedicine in loading the oxaliplatin parent complex (1,2-diaminocyclohexane)platinum(II)-loaded polymeric micelles (DACHPt/m) against multiple liver metastases from colon cancer in a mouse model. MATERIALS AND METHODS: The efficacy of DACHPt/m or oxaliplatin (on days 14 and 21 after inoculation of tumor cells) was evaluated in a mouse model of liver metastasis for murine colon adenocarcinoma C26 cells. In vivo antitumor effects were evaluated by recording the number of liver metastases and weights of metastatic livers after treatment (day 28)...
October 2017: Journal of Surgical Research
https://www.readbyqxmd.com/read/28981909/cellular-ion-interactions-in-two-endemic-tropical-rainforest-species-of-a-novel-metallophytic-tree-genus
#20
Denise R Fernando, Alan T Marshall, Peter T Green
Gossia, a small genus of physiologically novel rainforest trees restricted to the Western Pacific and belonging to a key neotropical Southern Hemisphere family, the Myrtaceae, is characterized by high foliar manganese (Mn) concentrations. This field study provides a quantitative in planta snapshot detailing cellular localization of foliar Mn and other mineral nutrients in sympatric Gossia grayi N. Snow & Guymer and Gossia shepherdii N. Snow & Guymer endemic to far northeastern Australia, and previously not examined...
September 6, 2017: Tree Physiology
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