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https://www.readbyqxmd.com/read/28324643/unsymmetrical-iron-p-nh-p-catalysts-for-the-asymmetric-pressure-hydrogenation-of-aryl-ketones
#1
Robert Harold Morris, Samantha Alizabeth Michelle Smith, Paraskevi Olympia Lagaditis, Alan J Lough, Anne Lüpke
The reductive amination of -dialkylphosphine acetaldehydes with enantiopure -aminophosphines is a new, versatile route to unsymmetrical tridentate (pincer) ligands P-NH-P'. Four new ligands PR2CH2CH2NHCHR'CHR''PPh2 (R = iPr, Cy, R' = Ph, CH(CH3)2, R'' = Ph, H) prepared in this way are used to make the iron(II) complexes mer-FeCl2(CO)(P-NH-P') and mer-FeCl(H)(CO)(P-NH-P'). The hydride complex with the rigid ligand with R'= R''= Ph is an efficient and highly enantioselective homogeneous asymmetric pressure hydrogenation (APH) catalyst...
March 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28319739/mechanism-and-kinetics-of-halogenated-compound-removal-by-metallic-iron-transport-in-solution-diffusion-and-reduction-within-corrosion-films
#2
Shun Tang, Xiao-Mao Wang, Shi-Ting Liu, Hong-Wei Yang, Yuefeng F Xie, Xiao-Yi Yang
A detailed kinetic model comprised of mass transport (ktra), pore diffusion (kdif), adsorption and reduction reaction (krea), was developed to quantitatively evaluate the effect of corrosion films on the removal rate (kobs) of halogenated compounds by metallic iron. Different corrosion conditions were controlled by adjusting the iron aging time (0 or 1 yr) and dissolved oxygen concentration (0-7.09 mg/L DO). The kobs values for bromate, mono-, di- and tri-chloroacetic acids (BrO3(-), MCAA, DCAA and TCAA) were 0...
March 6, 2017: Chemosphere
https://www.readbyqxmd.com/read/28319068/iron-addiction-a-novel-therapeutic-target-in-ovarian-cancer
#3
D Basuli, L Tesfay, Z Deng, B Paul, Y Yamamoto, G Ning, W Xian, F McKeon, M Lynch, C P Crum, P Hegde, M Brewer, X Wang, L D Miller, N Dyment, F M Torti, S V Torti
Ovarian cancer is a lethal malignancy that has not seen a major therapeutic advance in over 30 years. We demonstrate that ovarian cancer exhibits a targetable alteration in iron metabolism. Ferroportin (FPN), the iron efflux pump, is decreased, and transferrin receptor (TFR1), the iron importer, is increased in tumor tissue from patients with high grade but not low grade serous ovarian cancer. A similar profile of decreased FPN and increased TFR1 is observed in a genetic model of ovarian cancer tumor-initiating cells (TICs)...
March 20, 2017: Oncogene
https://www.readbyqxmd.com/read/28318824/a-kinetic-approach-on-hexavalent-chromium-removal-with-metallic-iron
#4
M Gheju, I Balcu, A Enache, A Flueras
This paper examines the mechanism of Cr(VI) removal with Fe(0), and the possible effect of various experimental parameters, from a kinetic perspective. The experimental data was analyzed using five different kinetic models: three for chemical reactions and two for adsorption processes. It was found that the process fitted well to the zero-order kinetic model for all investigated systems, excepting experiments conducted at 6 °C and those with nano-Fe(0), when the process followed the Ho's pseudo second-order model...
March 16, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28318691/evaluation-of-simulated-dredging-to-control-internal-phosphorus-release-from-sediments-focused-on-phosphorus-transfer-and-resupply-across-the-sediment-water-interface
#5
Juhua Yu, Shiming Ding, Jicheng Zhong, Chengxin Fan, Qiuwen Chen, Hongbin Yin, Lei Zhang, Yinlong Zhang
Sediment dredging is an effective restoration method to control the internal phosphorus (P) loading of eutrophic lakes. However, the core question is that the real mechanism of dredging responsible for sediment internal P release still remains unclear. In this study, we investigated the P exchange across the sediment-water interface (SWI) and the internal P resupply ability from the sediments after dredging. The study is based on a one-year field simulation study in Lake Taihu, China, using a Rhizon soil moisture sampler, high-resolution dialysis (HR-Peeper), ZrO-Chelex diffusive gradients in thin film (ZrO-Chelex DGT), and P fractionation and adsorption isotherm techniques...
March 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28317737/identification-of-the-key-excreted-molecule-by-lactobacillus-fermentum-related-to-host-iron-absorption
#6
Ana González, Natividad Gálvez, Jesús Martín, Fernando Reyes, Ignacio Pérez-Victoria, Jose M Dominguez-Vera
We have taken a vital step towards understanding why probiotic bacteria increase iron absorption in the gastrointestinal tract. We show here that Lactobacillus fermentum, one of the main probiotics of the microbiota, exhibits an extraordinary ferric-reducing activity. This activity is predominantly due to an excreted molecule: p-hydroxyphenyllactic acid (HPLA). Reduction of Fe(III) to Fe(II) is essential for iron absorption in the gastrointestinal tract. By reducing Fe(III), HPLA boosts Fe(II) absorption through the DMT1 channels of enterocytes...
August 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28316232/in-vitro-reduction-of-arsenic-bioavailability-using-dietary-strategies
#7
M J Clemente, V Devesa, D Velez
The main route of human exposure to inorganic arsenic (As) is through consumption of food and water. Continued exposure to inorganic As [As(III) and As(V)] may cause a variety of diseases, including various types of cancer. Removal of As from these sources is complex, especially for food. One way to decrease As exposure could be by reducing intestinal absorption of it. The aim of this study is to seek dietary strategies (pure compounds, extracts, or supplements) that are capable of reducing the amount of As that is absorbed and reaches the systemic circulation...
March 20, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28316044/changes-and-relations-of-photosynthesis-and-iron-cycling-in-anoxic-paddy-soil-amended-with-high-concentrations-of-sulfate
#8
Qin Chen, Rong Jia, Dong Qu, Ming Li
Sulfate contamination is an increasingly serious environmental problem related to microbial reduction processes in anoxic paddy soil. This study revealed the changes and interrelations of ferric iron [Fe(III)] reduction, ferrous iron [Fe(II)] oxidation, and oxygenic photosynthesis in an anoxic paddy soil (Fe-accumuli-Stagnic Anthrosols) amended with a range of high sulfate concentrations. Soil slurries mixed with 0 (control), 50, 100, 200, and 400 mmol kg(-1) Na2SO4 were incubated anaerobically under dark and light conditions...
March 18, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28304018/graphene-nanobubbles-on-tio2-for-in-operando-electron-spectroscopy-of-liquid-phase-chemistry
#9
S Nappini, A Matruglio, D Naumenko, S Dal Zilio, F Bondino, M Lazzarino, E Magnano
X-Ray Photoelectron Spectroscopy (XPS) and X-Ray Absorption Spectroscopy (XAS) provide unique knowledge on the electronic structure and chemical properties of materials. Unfortunately this information is scarce when investigating solid/liquid interfaces and chemical or photochemical reactions under ambient conditions because of the short electron inelastic mean free path (IMFP) that requires a vacuum environment, which poses serious limitation on the application of XPS and XAS to samples present in the atmosphere or in the presence of a solvent...
March 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28303424/inherited-disorders-of-transition-metal-metabolism-an-update
#10
REVIEW
Peter T Clayton
Elements with a biological role include six trace transition metals: manganese, iron, cobalt, copper, zinc and molybdenum. Transition metals participate in group transfer reactions such as glycosylation and phosphorylation and those that can transfer an electron by alternating between two redox states such as iron (3+/2+) and copper (2+/1+) are also very important in biological redox reactions including the reduction of molecular oxygen and the transport of oxygen. However, these trace metals are also potentially toxic, generating reactive oxygen species through Fenton chemistry...
March 16, 2017: Journal of Inherited Metabolic Disease
https://www.readbyqxmd.com/read/28301717/glucose-triggered-insulin-release-from-fe3-cross-linked-alginate-hydrogel-experimental-study-and-theoretical-modeling
#11
Evgeny Katz, Sabrina Scheja, Sergii Domanskyi, Maria Gamella, Kelly L Wormwood, Costel C Darie, Arshak Poghossian, Michael J Schöning, Artem Melman, Vladimir Privman
We study the mechanisms involved in the release, triggered by the application of glucose, of insulin entrapped in Fe3+-cross-linked alginate hydrogel particles further stabilized with a polyelectrolyte. Platelet-shaped alginate particles are synthesized containing enzyme glucose oxidase conjugated with silica nanoparticles, which are also entrapped in the hydrogel. Glucose diffuses in from solution, and production of hydrogen peroxide is catalyzed by the enzyme within the hydrogel. We argue that, specifically for the Fe3+-cross-linked systems, the produced hydrogen peroxide is further converted to free radicals via a Fenton-type reaction catalyzed by the iron cations...
March 16, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28300773/the-low-fodmap-diet-many-question-marks-for-a-catchy-acronym
#12
REVIEW
Giulia Catassi, Elena Lionetti, Simona Gatti, Carlo Catassi
FODMAP, "Fermentable Oligo-, Di- and Mono-saccharides And Polyols", is a heterogeneous group of highly fermentable but poorly absorbed short-chain carbohydrates and polyols. Dietary FODMAPs might exacerbate intestinal symptoms by increasing small intestinal water volume, colonic gas production, and intestinal motility. In recent years the low-FODMAP diet for treatment of irritable bowel syndrome (IBS) has gained increasing popularity. In the present review we aim to summarize the physiological, clinical, and nutritional issues, suggesting caution in the prolonged use of this dietary treatment on the basis of the existing literature...
March 16, 2017: Nutrients
https://www.readbyqxmd.com/read/28299304/effects-of-phlebotomy-on-liver-enzymes-and-histology-of-patients-with-nonalcoholic-fatty-liver-disease
#13
Mahsa Khodadoostan, Maryam Zamanidoost, Ahmad Shavakhi, Hosein Sanei, Masood Shahbazi, Mehdi Ahmadian
BACKGROUND: Nonalcoholic fatty liver disease (NAFLD), defined as excessive liver fat deposition and one of end-stage liver disease causes. Increased ferritin levels are associated with insulin resistance and a higher hepatic iron and fat content. Hyperferritinemia has been associated with severity of liver damage in NAFLD. The study aimed to evaluate the effects of phlebotomy on liver enzymes and histology in such patients. MATERIALS AND METHODS: Thirty-two eligible patients who had NAFLD and after 6 months of lifestyle modification still had NAFLD, and whose ferritin serum was above 250 mg/dl, were enrolled in this clinical trial study...
2017: Advanced Biomedical Research
https://www.readbyqxmd.com/read/28294603/structural-insights-into-the-nature-of-fe-0-and-fe-i-low-valent-species-obtained-upon-the-reduction-of-iron-salts-by-aryl-grignard-reagents
#14
Martin Clémancey, Thibault Cantat, Geneviève Blondin, Jean-Marc Latour, Pierre Dorlet, Guillaume Lefèvre
Mechanistic studies of the reduction of Fe(III) and Fe(II) salts by aryl Grignard reagents in toluene/tetrahydrofuran mixtures in the absence of a supporting ligand, as well as structural insights regarding the nature of the low-valent iron species obtained at the end of this reduction process, are reported. It is shown that several reduction pathways can be followed, depending on the starting iron precursor. We demonstrate, moreover, that these pathways lead to a mixture of Fe(0) and Fe(I) complexes regardless of the nature of the precursor...
March 15, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28294213/towards-artificial-methanogenesis-biosynthesis-of-the-fe-hydrogenase-cofactor-and-characterization-of-the-semi-synthetic-hydrogenase
#15
Liping Bai, Takashi Fujishiro, Gangfeng Huang, Jürgen Koch, Atsushi Takabayashi, Makio Yokono, Ayumi Tanaka, Tao Xu, Xile Hu, Ulrich Ermler, Seigo Shima
The greenhouse gas and energy carrier methane is produced on Earth mainly by methanogenic archaea. In the hydrogenotrophic methanogenic pathway the reduction of one CO2 to one methane molecule requires four molecules of H2 containing eight electrons. Four of the electrons from two H2 are supplied for reduction of an electron carrier F420, which is catalyzed by F420-reducing [NiFe]-hydrogenase under nickel-sufficient conditions. The same reaction is catalysed under nickel-limiting conditions by [Fe]-hydrogenase coupled with a reaction catalyzed by F420-dependent methylene tetrahydromethanopterin dehydrogenase...
March 15, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28293428/photocatalytic-degradation-of-atrazine-herbicide-with-illuminated-fe-3-tio2-nanoparticles
#16
Narges Shamsedini, Mansooreh Dehghani, Simin Nasseri, Mohammad Ali Baghapour
BACKGROUND: Atrazine is a herbicide that is widely used to control broadleaf and grassy weeds for growing many crops especially in maize production. It is a frequently detected herbicide in many groundwater resources. This study aimed to assess the feasibility of using ultraviolet radiation UV and fortified nanoparticles of titanium dioxide (TiO2) doped with trivalent iron to remove atrazine from aqueous phase and determin the removal efficiency under the optimal conditions. RESULTS: The results of this study demonstrated that the maximum atrazine removal rate was at pH = 11 in the presence of Fe(+ 3)-TiO2 catalyst =25 mg/L and the initial concentration of atrazine equal to 10 mg/L...
2017: Journal of Environmental Health Science & Engineering
https://www.readbyqxmd.com/read/28291336/direct-observation-of-an-iron-bound-terminal-hydride-in-fefe-hydrogenase-by-nuclear-resonance-vibrational-spectroscopy
#17
Edward J Reijerse, Cindy C Pham, Vladimir Pelmenschikov, Ryan Gilbert-Wilson, Agnieszka Adamska-Venkatesh, Judith F Siebel, Leland B Gee, Yoshitaka Yoda, Kenji Tamasaku, Wolfgang Lubitz, Thomas B Rauchfuss, Stephen P Cramer
[FeFe]-hydrogenases catalyse the reversible reduction of protons to molecular hydrogen with extremely high efficiency. The active site ("H-cluster") consists of a [4Fe-4S]H cluster linked through a bridging cysteine to a [2Fe]H subsite coordinated by CN(-) and CO ligands featuring a dithiol-amine moiety which serves as proton shuttle between the protein proton channel and the catalytic distal iron site (Fed). Although there is broad consensus that an iron bound terminal hydride species must occur in the catalytic mechanism, such a species has never been directly observed experimentally...
March 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28289188/ligand-induced-allostery-in-the-interaction-of-the-pseudomonas-aeruginosa-heme-binding-protein-with-heme-oxygenase
#18
Daniel J Deredge, Weiliang Huang, Colleen Hui, Hirotoshi Matsumura, Zhi Yue, Pierre Moënne-Loccoz, Jana Shen, Patrick L Wintrode, Angela Wilks
A heme-dependent conformational rearrangement of the C-terminal domain of heme binding protein (PhuS) is required for interaction with the iron-regulated heme oxygenase (HemO). Herein, we further investigate the underlying mechanism of this conformational rearrangement and its implications for heme transfer via site-directed mutagenesis, resonance Raman (RR), hydrogen-deuterium exchange MS (HDX-MS) methods, and molecular dynamics (MD). HDX-MS revealed that the apo-PhuS C-terminal α6/α7/α8-helices are largely unstructured, whereas the apo-PhuS H212R variant showed an increase in structure within these regions...
March 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28287409/sirtuin-2-regulates-cellular-iron-homeostasis-via-deacetylation-of-transcription-factor-nrf2
#19
Xiaoyan Yang, Seong-Hoon Park, Hsiang-Chun Chang, Jason S Shapiro, Athanassios Vassilopoulos, Konrad T Sawicki, Chunlei Chen, Meng Shang, Paul W Burridge, Conrad L Epting, Lisa D Wilsbacher, Supak Jenkitkasemwong, Mitchell Knutson, David Gius, Hossein Ardehali
SIRT2 is a cytoplasmic sirtuin that plays a role in various cellular processes, including tumorigenesis, metabolism, and inflammation. Since these processes require iron, we hypothesized that SIRT2 directly regulates cellular iron homeostasis. Here, we have demonstrated that SIRT2 depletion results in a decrease in cellular iron levels both in vitro and in vivo. Mechanistically, we determined that SIRT2 maintains cellular iron levels by binding to and deacetylating nuclear factor erythroid-derived 2-related factor 2 (NRF2) on lysines 506 and 508, leading to a reduction in total and nuclear NRF2 levels...
March 13, 2017: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/28286378/iron-reduces-m1-macrophage-polarization-in-raw264-7-macrophages-associated-with-inhibition-of-stat1
#20
Zhen-Shun Gan, Qian-Qian Wang, Jia-Hui Li, Xu-Liang Wang, Yi-Zhen Wang, Hua-Hua Du
Iron metabolism in inflammation has been mostly characterized in macrophages exposed to pathogens or inflammatory conditions. The aim of this study is to investigate the cross-regulatory interactions between M1 macrophage polarization and iron metabolism. Firstly, we characterized the transcription of genes related to iron homeostasis in M1 RAW264.7 macrophages stimulated by IFN-γ. The molecular signature of M1 macrophages showed high levels of iron storage (ferritin), a low level of iron export (ferroportin), and changes of iron regulators (hepcidin and transferrin receptors), which favour iron sequestration in the reticuloendothelial system and are benefit for inflammatory disorders...
2017: Mediators of Inflammation
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