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https://www.readbyqxmd.com/read/28350469/synthesis-of-sugar-boronic-acid-derivatives-a-class-of-potential-agents-for-boron-neutron-capture-therapy
#1
Daniela Imperio, Erika Del Grosso, Silvia Fallarini, Grazia Lombardi, Luigi Panza
To date, sugar analogues that contain boronic acids as substitutes for hydroxyl groups are a class of compounds nearly unknown in the literature. The challenging synthesis of two sugar-boronic acid analogues is described, and data are retrieved on their solution behavior, stability, and toxicity. As these compounds were expected to mimic the behavior of carbohydrates, they were tested in regards to their future development as potential boron neutron capture therapy agents.
March 28, 2017: Organic Letters
https://www.readbyqxmd.com/read/28346554/fundamental-insights-into-interfacial-catalysis
#2
EDITORIAL
Jinlong Gong, Xinhe Bao
Surface and interfacial catalysis plays a vital role in chemical industries, electrochemistry and photochemical reactions. The challenges of modern chemistry are to optimize the chemical reaction processes and understand the detailed mechanism of chemical reactions. Since the early 1960s, the foundation of surface science systems has allowed the study of surface and interfacial phenomena on atomic/molecular level, and thus brought a number of significant developments to fundamental and technological processes, such as catalysis, material science and biochemistry, just to name a few...
March 27, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28345908/rapid-low-temperature-formation-of-imine-linked-cofs-catalyzed-by-metal-triflates
#3
Michio Matsumoto, Raghunath R Dasari, Woojung Ji, Cameron H Feriante, Timothy C Parker, Seth R Marder, William R Dichtel
Imine-linked two-dimensional covalent organic frameworks (2D COFs) are crystalline polymer networks with enhanced stability and broader monomer scope compared to boronate ester-linked systems. They are traditionally prepared by condensing polyfunctional aldehydes and amines at elevated temperature in a mixture of organic solvents and aqueous CH3CO2H, which catalyzes imine formation and exchange. Under these conditions, an amorphous imine-linked polymer network precipitates quickly and then crystallizes after extended reaction times (hours to days)...
March 27, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28345866/biocompatible-hydroxylated-boron-nitride-nanosheets-polyvinyl-alcohol-interpenetrating-hydrogels-with-enhanced-mechanical-and-thermal-responses
#4
Lin Jing, Hongling Li, Roland Yingjie Tay, Bo Sun, Siu Hon Tsang, Olivier Cometto, Jinjun Lin, Edwin Hang Tong Teo, Alfred Iing Yoong Tok
Polyvinyl alcohol (PVA) hydrogels with tissue-like viscoelasticity, excellent biocompatibility and high hydrophilicity have been considered as promising cartilage replacement materials. However, lack of sufficient mechanical properties is a critical barrier to their usage as load-bearing cartilage substitutes. Herein, we report hydroxylated boron nitride nanosheets (OH-BNNS)/PVA interpenetrating hydrogels by cyclically freezing/thawing the aqueous mixture of PVA and highly hydrophilic OH-BNNS (up to 0.6 mg/mL, two times the highest reported so far)...
March 27, 2017: ACS Nano
https://www.readbyqxmd.com/read/28345350/boron-enhanced-growth-of-micron-length-carbon-based-nanowalls-a-route-towards-high-rates-electrochemical-biosensing
#5
Katarzyna Siuzdak, Mateusz Ficek, Michal Sobaszek, Jacek Ryl, Marcin Gnyba, Paweł Niedziałkowski, Natalia Malinowska, Jakub Karczewski, Robert Bogdanowicz
In this study we have demonstrated the fabrication of novel material called boron-doped carbon nanowalls (B:CNW) which is characterized by remarkable electrochemical properties like high standard rate constant k°, low peak to peak separation value (ΔE) for oxidation and reduction processes of [Fe(CN)6]3-/4- redox system and low surface resistivity. The B:CNW samples were deposited by the microwave plasma assisted chemical vapor deposition (CVD) using a gas mixture of H2:CH4:B2H6 and N2. Growth results in sharp edge, flat and long carbon nanowalls rich in sp2 as well as sp3 hybridized phases...
March 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28345349/a-self-assembled-ratiometric-polymeric-nanoprobe-for-highly-selective-fluorescence-detection-of-hydrogen-peroxide
#6
Chongchong Feng, Fengyang Wang, Yijing Dang, Zhiai Xu, Haijun Yu, Wen Zhang
In this study, a dual-emission fluorescence resonance energy transfer (FRET) polymeric nanoprobe by single-wavelength excitation was developed for sensitive and selective hydrogen peroxide (H2O2) detection. Polymeric nanoprobe was prepared by simple self-assembly of functional lipopolymers, which were 4-carboxy-3-fluorophenylboronic acid (FPBA)-modified DSPE-PEG (DSPE-PEG-FPBA) and 7-hydroxycoumarin (HC)-conjugated DSPE-PEG (DSPE-PEG-HC). Subsequent binding of alizarin red S (ARS) to FPBA endowed the nanoprobe with a new fluorescence emission peak at around 600 nm...
March 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28345090/exhaustive-suzuki-miyaura-reactions-of-polyhalogenated-heteroarenes-with-alkyl-boronic-pinacol-esters
#7
Sébastien Laulhé, J Miles Blackburn, Jennifer L Roizen
A novel Suzuki-Miyaura protocol is described that enables the exhaustive alkylation of polychlorinated pyridines. This method facilitates a formal synthesis of normuscopyridine and the rapid assembly of a dumbbell shaped portion of a [2]rotaxane.
March 27, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28342380/optimization-of-the-compton-camera-for-measuring-prompt-gamma-rays-in-boron-neutron-capture-therapy
#8
Chun-Hui Gong, Xiao-Bin Tang, Di-Yun Shu, Hai-Yan Yu, Chang-Ran Geng
Optimization of the Compton camera for measuring prompt gamma rays (0.478MeV) emitted during boron neutron capture therapy (BNCT) was performed with Geant4. The parameters of the Compton camera were determined as follows: 3cm thick - 10cm wide scatter detector (Silicon), 10cm thick - 10cm wide absorber detector (Germanium), and 1cm distance between the scatter and absorber detectors. For a typical brain tumor treatment, the overall detection efficiency of the optimized Compton camera was approximately 0.1425% using the Snyder's head phantom with a sphere tumor (4cm diameter and ~1cm depth)...
March 19, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28342369/sensing-properties-of-monolayer-borophane-nanosheet-towards-alcohol-vapors-a-first-principles-study
#9
V Nagarajan, R Chandiramouli
The electronic properties of borophane nanosheet and adsorption behavior of three distinct alcohol vapors namely methanol, ethanol and 1-propanol on borophane nanosheet is studied using density functional theory method for the first time. The state-of-the-art provides insights on to the development of new two dimensional materials with the surface passivation on boron nanostructures. The density of states spectrum provides a clear perception on charge transfer upon adsorption of alcohol vapors on borophane nanosheets...
February 8, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28342198/an-isolable-diboron-centered-diradical-with-a-triplet-ground-state
#10
Lei Wang, Yong Fang, Haochuan Mao, Yi Qu, Jiacheng Zuo, Zaichao Zhang, Gengwen Tan, Xinping Wang
Two new diboranes 2,6-bis(BMes2)mesitylene (1) and 3,3'-bis(BMes2)bimesitylene (3) were synthesized. Two-electron reduction of 1 with elemental potassium afforded the C-H activation product [(18-c-6)K(THF)2]2+*22- bearing a BC3 four-membered ring as colorless crystals, whereas the reduction of 3 with potassium led to the isolation of [(18-c-6)K(THF)2]2+*32-** as dark blue crystals. Both reduction products were characterized by structural and spectroscopic methods. The EPR spectroscopy and theoretical calculations reveal that the electron spin density of 32-** mainly resides on the two boron nuclei, and it features a triplet ground state, which was confirmed by SQUID measurements as well as theoretical calculations...
March 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28341806/polar-localization-of-the-nip5-1-boric-acid-channel-is-maintained-by-endocytosis-and-facilitates-boron-transport-in-arabidopsis-roots
#11
Sheliang Wang, Akira Yoshinari, Tomoo Shimada, Ikuko Hara-Nishimura, Namiki Mitani-Ueno, Jian Feng Ma, Satoshi Naito, Junpei Takano
Boron uptake in Arabidopsis thaliana is mediated by nodulin 26-like intrinsic protein (NIP)5;1, a boric acid channel that is located preferentially on the soil side of the plasma membrane in root cells. However, the mechanism underlying this polar localization is poorly understood. Here, we show that the polar localization of NIP5;1 in epidermal and endodermal root cells is mediated by the phosphorylation of Thr residues in the conserved TPG (ThrProGly) repeat in the N-terminal region of NIP5;1. Although substitutions of Ala for three Thr residues in the TPG repeat did not affect lateral diffusion in the plasma membrane, these substitutions inhibited endocytosis and strongly compromised the polar localization of GFP-NIP5;1...
March 24, 2017: Plant Cell
https://www.readbyqxmd.com/read/28340712/a-double-mediator-based-whole-cell-electrochemical-biosensor-for-acute-biotoxicity-assessment-of-wastewater
#12
Guanyue Gao, Deyu Fang, Yuan Yu, Liangzhuan Wu, Yu Wang, Jinfang Zhi
This work investigates the feasibility and sensitivity of a double-mediator based whole cell electrochemical biosensor to detect the acute biotoxicity of wastewater. The lipophilic mediator menadione was used to mediate the intracellular metabolic activities whereas hydrophilic potassium ferricyanide was employed as extracellular electron acceptor to transport the electron from the menadiol to anode. A chitosan hydrogel polymer film with boron-doped nanocrystalline diamond (BND) particles was electrodeposited onto a glassy carbon (GC) electrode to immobilize Saccharomyces cerevisiae cells and the mediators...
May 15, 2017: Talanta
https://www.readbyqxmd.com/read/28339256/analytic-interatomic-forces-in-the-random-phase-approximation
#13
Benjamin Ramberger, Tobias Schäfer, Georg Kresse
We discuss that in the random phase approximation (RPA) the first derivative of the energy with respect to the Green's function is the self-energy in the GW approximation. This relationship allows us to derive compact equations for the RPA interatomic forces. We also show that position dependent overlap operators are elegantly incorporated in the present framework. The RPA force equations have been implemented in the projector augmented wave formalism, and we present illustrative applications, including ab initio molecular dynamics simulations, the calculation of phonon dispersion relations for diamond and graphite, as well as structural relaxations for water on boron nitride...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339229/first-principles-based-method-for-electron-localization-application-to-monolayer-hexagonal-boron-nitride
#14
C E Ekuma, V Dobrosavljević, D Gunlycke
We present a first-principles-based many-body typical medium dynamical cluster approximation and density function theory method for characterizing electron localization in disordered structures. This method applied to monolayer hexagonal boron nitride shows that the presence of boron vacancies could turn this wide-gap insulator into a correlated metal. Depending on the strength of the electron interactions, these calculations suggest that conduction could be obtained at a boron vacancy concentration as low as 1...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339126/boron-doped-polygonal-carbon-nano-onions-synthesis-and-applications-in-electrochemical-energy-storage
#15
Marta Eliza Plonska-Brzezinska, Olena Mykhailiv, Krzysztof Brzezinski, Bogdan Sulikowski, Zbigniew Olejniczak, Malgorzata Gras, Grzegorz Lota, Agustin Molina-Ontoria, Michal Jakubczyk, Luis Echegoyen
Doping of carbon nanostructures with heteroatoms, such as boron or nitrogen, is one of the most effective ways to change their properties to make them suitable for various applications. Carbon nano-onions (CNOs) doped with boron (B-CNOs) have been prepared by annealing (1650°C) nanodiamond particles (NDs) under an inert He atmosphere in the presence of B. Their physicochemical properties were measured using transmission (TEM) and scanning (SEM) electron microscopy, X-ray photoelectron spectroscopy (XPS), 10B and 11B solid-state MAS NMR spectroscopy, X-ray powder diffractions (XRD), Raman spectroscopy, porosimetry, and differential-thermogravimetric analyses (TGA-DTG)...
March 24, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28338895/photosynthesis-nutrient-accumulation-and-growth-of-two-betula-species-exposed-to-waterlogging-in-late-dormancy-and-in-the-early-growing-season
#16
Ai-Fang Wang, Marja Roitto, Tarja Lehto, Sirkka Sutinen, Jaakko Heinonen, Gang Zhang, Tapani Repo, Ram Oren
Increased risk of soil waterlogging in winter and spring at northern latitudes will potentially affect forest production in the future. We studied gas exchange, chlorophyll content index, chlorophyll fluorescence, nutrient concentration and biomass accumulation in 1-year-old silver (Betula pendula Roth) and pubescent birch (Betula pubescens Ehrh.) seedlings. We hypothesized that B. pubescens has different physiological mechanisms that make it tolerate waterlogging better than B. pendula. The treatments were: (i) no waterlogging throughout the experiment; (ii) 4-week waterlogging during dormancy (dormancy waterlogging 'DW'); (iii) 4-week waterlogging during the early growing season (growth waterlogging 'GW'); and (iv) 4-week DW followed by 4-week GW during the early growing season ('DWGW')...
March 15, 2017: Tree Physiology
https://www.readbyqxmd.com/read/28338284/palladium-catalyzed-enantioselective-synthesis-of-2-aryl-cyclohex-2-enone-atropisomers-platform-molecules-for-the-divergent-synthesis-of-axially-chiral-biaryl-compounds
#17
Chongqing Pan, Zixi Zhu, Mingkai Zhang, Zhenhua Gu
The palladium-catalyzed asymmetric synthesis of enone-based atropisomers from 2-iodo-3-methylcyclohex-2-enones and aryl boronic acid is reported. BoPhoz-type phosphine-aminophosphine ligands showed superior enantioselectivity over other ligands. These cyclohexenone-based atropisomers are useful compounds for further elaboration. The divergent synthesis of biaryl atropisomers with different ortho substituents was demonstrated.
March 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28338279/elemental-boron-for-efficient-carbon-dioxide-reduction-under-light-irradiation
#18
Guigao Liu, Xianguang Meng, Huabin Zhang, Guixia Zhao, Hong Pang, Tao Wang, Peng Li, Tetsuya Kako, Jinhua Ye
The photoreduction of CO2 is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO2 reduction over elemental boron catalysts in the presence of only water and light irradiation through a photothermocatalytic process. Owing to its high solar-light absorption and effective photothermal conversion, the illuminated boron catalyst experiences remarkable self-heating. This process favors CO2 activation and also induces localized boron hydrolysis to in situ produce H2 as an active proton source and electron donor for CO2 reduction as well as boron oxides as promoters of CO2 adsorption...
March 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28337401/a-rapid-approach-for-fabricating-boronic-acid-functionalized-plates-for-on-probe-detection-of-glycoprotein-and-glycopeptide
#19
Yu-Ching Liu, Chao-Jung Chen
We developed a rapid and simple approach without using complex mechanical or chemical protocols to fabricate boronic acid-functionalized plates for glycoprotein or glycopeptide enrichment and mass spectrometry (MS) analysis. By coating the boronic acid-functionalized silica particles on a polydimethylsiloxane (PDMS)-coated matrix-assisted laser desorption/ionization (MALDI) plate, these particles can form a firmly monolayer of particles on PDMS membrane for sample handling without peeling off. The boronic acid particles-coated PDMS plate (BP plate) was successfully applied to the enrichment of horseradish peroxidase (HRP) protein and their digested glycopeptides...
2017: Mass Spectrometry
https://www.readbyqxmd.com/read/28336931/observation-of-biexcitonic-emission-at-extremely-low-power-density-in-tungsten-disulfide-atomic-layers-grown-on-hexagonal-boron-nitride
#20
Mitsuhiro Okada, Yuhei Miyauchi, Kazunari Matsuda, Takashi Taniguchi, Kenji Watanabe, Hisanori Shinohara, Ryo Kitaura
Monolayer transition metal dichalcogenides (TMDCs) including WS2, MoS2, WSe2 and WS2, are two-dimensional semiconductors with direct bandgap, providing an excellent field for exploration of many-body effects in 2-dimensions (2D) through optical measurements. To fully explore the physics of TMDCs, the prerequisite is preparation of high-quality samples to observe their intrinsic properties. For this purpose, we have focused on high-quality samples, WS2 grown by chemical vapor deposition method with hexagonal boron nitride as substrates...
March 23, 2017: Scientific Reports
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