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https://www.readbyqxmd.com/read/28454048/antibacterial-activity-of-biochemically-capped-iron-oxide-nanoparticles-a-view-towards-green-chemistry
#1
Rabia Irshad, Kamran Tahir, Baoshan Li, Aftab Ahmad, Azka R Siddiqui, Sadia Nazir
A green approach to fabricate nanoparticles has been evolved as a revolutionary discipline. Eco-compatible reaction set ups, use of non-toxic materials and production of highly active biological and photocatalytic products are few benefits of this greener approach. Here, we introduce a green method to synthesize Fe oxide NPs using Punica granatum peel extract. The formation of Fe oxide NPs was optimized using different concentrations of peel extract (20mL, 40mL and 60mL) to achieve small size and better morphology...
April 19, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28453538/variation-of-iron-redox-kinetics-and-its-relation-with-molecular-composition-of-standard-humic-substances-at-circumneutral-ph
#2
Ying Ping Lee, Manabu Fujii, Tetsuro Kikuchi, Koumei Terao, Chihiro Yoshimura
Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II) oxidation were examined in air-saturated solution using luminol chemiluminescence technique...
2017: PloS One
https://www.readbyqxmd.com/read/28453309/combination-of-cyclodextrin-and-ionic-liquid-in-analytical-chemistry-current-and-future-perspectives
#3
Y H Boon, M Raoov, N N M Zain, S Mohamad, H Osman
The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. Cyclodextrins belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds...
April 28, 2017: Critical Reviews in Analytical Chemistry
https://www.readbyqxmd.com/read/28453276/computational-chemical-kinetics-for-the-reaction-of-criegee-intermediate-ch2oo-with-hno3-and-its-catalytic-conversion-to-oh-and-hco
#4
Putikam Raghunath, Yuan-Pern Lee, Ming-Chang Lin
The kinetics and mechanisms for the reaction of the Criegee intermediate CH2OO with HNO3 and the unimolecular decomposition of its reaction product CH2(O)NO3 are important in atmospheric chemistry. The potential-energy profile of the reactions predicted with the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ method shows that the initial association yields a pre-reaction complex that isomerizes by H migration to yield excited intermediate nitrooxymethyl hydroperoxide NO3CH2OOH* with internal energy ~44 kcal mol(-1)...
April 28, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28453260/origin-of-outstanding-phase-and-moisture-stability-in-na3p1-xasxs4-superionic-conductor
#5
Shun-Li Shang, Zhaoxin Yu, Yi Wang, Donghai Wang, Zi-Kui Liu
Sodium-ion (Na) solid-state electrolytes (SSEs) are critical to address notorious safety issue associated with liquid electrolytes used in the current Na-ion batteries. Fulfilling multiple innovations is a grand challenge but imperative for advanced Na-ion SSE such as a combination of high ionic conductivity and excellent chemical stability. Here, our first-principles and phonon calculations reveal that Na3P1-xAsxS4 (0 ≤ x ≤ 1) is a solid-state superionic conductor stabilized at 0 K by zero-point vibrational energy and at finite temperatures by vibrational and configurational entropies...
April 28, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28449545/structural-variety-and-adsorptive-properties-of-mesoporous-silicas-with-immobilized-oligosaccharide-groups
#6
Iryna Trofymchuk, Nadiia Roik, Lyudmila Belyakova
In this research, we report on the synthesis of mesoporous silicas with various quantities of immobilized oligosaccharide groups and different pore ordering degree. The hydrothermal co-condensation of tetraethyl orthosilicate and β-cyclodextrin-containing organosilane in the presence of cetyltrimethylammonium bromide template was employed. The purpose of this investigation was to show the opportunity of increasing β-cyclodextrin content in silica matrix by changing the molar ratio of initial reagents during organosilane synthesis and to determine whether the enhancing of immobilized groups on the surface influences on model aromatic compound adsorption from water...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28449411/spectroscopic-characterization-of-the-reaction-products-between-criegee-intermediate-ch2oo-and-hcl
#7
Carlos Cabezas, Yasuki Endo
Pulsed Fourier-transform microwave experiments have been performed to probe the products resulting from the reaction between HCl and the simplest Criegee intermediate, CH₂OO, where the reaction is considered to be important in atmospheric chemistry. The experimentally determined rotational parameters interpreted with the help of quantum chemical calculations support the identification of chloro-methyl hydroperoxide molecule as the primary product of this reaction.
April 27, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28448880/rapid-green-synthesis-of-gold-nanocatalyst-for-high-efficiency-degradation-of-quinclorac
#8
Guorong Shi, Yulu Li, Gaihong Xi, Qinqin Xu, Zijun He, Yating Liu, Jianhui Zhang, Jun Cai
Porous chemical pretreated Saccharomyces cerevisiae was used as support, stabilizer, and reducing agent for the rapid green synthesis of gold nanocatalyst. Au nanoparticles (Au NPs) were generated through in-situ reduction of the absorbed Au(III) by the reductive functional groups of mannoproteins in yeast cell wall. The obtained spherical mono-dispersed Au NPs have an average particle diameter of 9.99±1.63nm as evidenced by TEM image, and exhibits excellent catalytic activity for the dechlorination of quinclorac to 8-quinoline-carboxylic acid by sodium borohydride...
April 18, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28448638/a-minimal-model-of-burst-noise-induced-bistability
#9
Johannes Falk, Marc Mendler, Barbara Drossel
We investigate the influence of intrinsic noise on stable states of a one-dimensional dynamical system that shows in its deterministic version a saddle-node bifurcation between monostable and bistable behaviour. The system is a modified version of the Schlögl model, which is a chemical reaction system with only one type of molecule. The strength of the intrinsic noise is varied without changing the deterministic description by introducing bursts in the autocatalytic production step. We study the transitions between monostable and bistable behavior in this system by evaluating the number of maxima of the stationary probability distribution...
2017: PloS One
https://www.readbyqxmd.com/read/28448553/a-computational-toxicogenomics-approach-identifies-a-list-of-highly-hepatotoxic-compounds-from-a-large-microarray-database
#10
Héctor A Rueda-Zárate, Iván Imaz-Rosshandler, Roberto A Cárdenas-Ovando, Juan E Castillo-Fernández, Julieta Noguez-Monroy, Claudia Rangel-Escareño
The liver and the kidney are the most common targets of chemical toxicity, due to their major metabolic and excretory functions. However, since the liver is directly involved in biotransformation, compounds in many currently and normally used drugs could affect it adversely. Most chemical compounds are already labeled according to FDA-approved labels using DILI-concern scale. Drug Induced Liver Injury (DILI) scale refers to an adverse drug reaction. Many compounds do not exhibit hepatotoxicity at early stages of development, so it is important to detect anomalies at gene expression level that could predict adverse reactions in later stages...
2017: PloS One
https://www.readbyqxmd.com/read/28448113/a-solvent-free-chemical-approach-to-synthesize-various-morphological-co3o4-for-co-oxidation
#11
Kun Wang, Yali Cao, Jindou Hu, Yizhao Li, Jing Xie, Dianzeng Jia
The synthesis of Co3O4 nanomaterials with diverse morphologies were usually synthesized in liquid phase accompanied by the template or surfactant, even harsh conditions, which further restricted their practical application. Herein, we reported an extremely simple and practical solid-state chemical method to synthesize Co3O4-octahedrons, -plates and -rods. Among these, the shape control of Co3O4-octahedrons and Co3O4-plates involve the variation of the amount of reactant, and the formation of Co3O4-rods with {110} facet can be achieved by replacing the reactant...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28447088/determination-of-the-diffusion-coefficient-of-hydrogen-ion-in-hydrogels
#12
Gábor Schuszter, Tünde Gehér-Herczegh, Árpád Szűcs, Ágota Tóth, Dezső Horváth
The role of diffusion in chemical pattern formation has been widely studied due to the great diversity of patterns emerging in reaction-diffusion systems, particularly in H(+)-autocatalytic reactions where hydrogels are applied to avoid convection. A custom-made conductometric cell is designed to measure the effective diffusion coefficient of a pair of strong electrolytes containing sodium ions or hydrogen ions with a common anion. This together with the individual diffusion coefficient for sodium ions, obtained from PFGSE-NMR spectroscopy, allows the determination of the diffusion coefficient of hydrogen ions in hydrogels...
April 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28446756/a-chemically-patterned-microfluidic-paper-based-analytical-device-c-%C3%A2%C2%B5pad-for-point-of-care-diagnostics
#13
Trinh Lam, Jasmine P Devadhasan, Ryan Howse, Jungkyu Kim
A chemically patterned microfluidic paper-based analytical device (C-µPAD) is developed to create fluidic networks by forming hydrophobic barriers using chemical vapor deposition (CVD) of trichlorosilane (TCS) on a chromatography paper. By controlling temperature, pattern size, and CVD duration, optimal conditions were determined by characterizing hydrophobicity, spreading patterns, and flow behavior on various sized fluidic patterns. With these optimal conditions, we demonstrated glucose assay, immunoassay, and heavy metal detection on well-spot C-µPAD and lateral flow C-µPAD...
April 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28446748/discovering-charge-density-functionals-and-structure-property-relationships-with-prophet-a-general-framework-for-coupling-machine-learning-and-first-principles-methods
#14
Brian Kolb, Levi C Lentz, Alexie M Kolpak
Modern ab initio methods have rapidly increased our understanding of solid state materials properties, chemical reactions, and the quantum interactions between atoms. However, poor scaling often renders direct ab initio calculations intractable for large or complex systems. There are two obvious avenues through which to remedy this problem: (i) develop new, less expensive methods to calculate system properties, or (ii) make existing methods faster. This paper describes an open source framework designed to pursue both of these avenues...
April 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28446335/quantitative-nano-characterization-of-polymers-using-atomic-force-microscopy
#15
Milad Radiom, Svilen Kozhuharov, Phally Kong, Michela di Giannantonio, Mathieu A Ayer, Plinio Maroni, Andreas F M Kilbinger, Katharina M Fromm, Christoph Weder, Michal Borkovec
The present article offers an overview on the use of atomic force microscopy (AFM) to characterize the nanomechanical properties of polymers. AFM imaging reveals the conformations of polymer molecules at solid- liquid interfaces. In particular, for polyelectrolytes, the effect of ionic strength on the conformations of molecules can be studied. Examination of force versus extension profiles obtained using AFM-based single molecule force spectroscopy gives information on the entropic and enthalpic elasticities in pN to nN force range...
April 26, 2017: Chimia
https://www.readbyqxmd.com/read/28446331/mechanistic-investigations-of-c-h-activations-on-silica-supported-co-ii-sites-in-catalytic-propane-dehydrogenation
#16
Deven P Estes
Catalytic reactions involving C-H bond activations are central to the chemical industry. One such example, alkane dehydrogenation, has recently become very important due to shortfalls in propene production and a large supply of cheap propane. However, current technologies are inefficient and have only moderate selectivity. In order to understand how to improve currently used catalysts, we must know more about the mechanism by which propane is dehydrogenated. We show here that Co(<small>ii</small>) sites on silica are good catalysts for the dehydrogenation of propane, having high activity and selectivity that is reasonably stable over the course of 10 h...
April 26, 2017: Chimia
https://www.readbyqxmd.com/read/28446330/automated-identification-of-relevant-frontier-orbitals-for-chemical-compounds-and-processes
#17
Christopher J Stein, Markus Reiher
Quantum-chemical multi-configurational methods are required for a proper description of static electron correlation, a phenomenon inherent to the electronic structure of molecules with multiple (near-)degenerate frontier orbitals. Here, we review how a property of these frontier orbitals, namely the entanglement entropy is related to static electron correlation. A subset of orbitals, the so-called active orbital space is an essential ingredient for all multi-configurational methods. We proposed an automated selection of this active orbital space, that would otherwise be a tedious and error prone manual procedure, based on entanglement measures...
April 26, 2017: Chimia
https://www.readbyqxmd.com/read/28446160/hydro-ethanolic-leaf-extract-of-ziziphus-abyssinica-hochst-ex-a-rich-rhamnaceae-exhibits-anti-nociceptive-effects-in-murine-models
#18
Eric Boakye-Gyasi, Isaac Tabiri Henneh, Wonder Kofi Mensah Abotsi, Elvis Ofori Ameyaw, Eric Woode
BACKGROUND: Despite substantial advances in pain research and treatment, millions of people continue to suffer from pain and this has been attributed mainly to the unavailability of effective and safer analgesics. The use of plants as medicines is still widespread and plants constitute a large source of novel phytocompounds that might become leads for the discovery of newer, effective and safer alternatives. Various parts of Ziziphus abyssinica have been used in folk medicine in several African countries as painkillers...
April 26, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28445748/directional-force-originating-from-atp-hydrolysis-drives-the-groel-conformational-change
#19
Jie Liu, Kannan Sankar, Yuan Wang, Kejue Jia, Robert L Jernigan
Protein functional mechanisms usually require conformational changes, and often there are known structures for the different conformational states. However, usually neither the origin of the driving force nor the underlying pathways for these conformational transitions is known. Exothermic chemical reactions may be an important source of forces that drive conformational changes. Here we investigate this type of force originating from ATP hydrolysis in the chaperonin GroEL, by applying forces originating from the chemical reaction...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445042/structural-transformation-of-mno2-during-the-oxidation-of-bisphenol-a
#20
Sarah Balgooyen, Peter J Alaimo, Christina K Remucal, Matthew Ginder-Vogel
Bisphenol A (BPA) is an endocrine-disrupting compound widely used in the plastic industry and found in natural waters at concentrations considered harmful for aquatic life. BPA is susceptible to oxidation by Mn(III/IV) oxides, which are commonly found in near-surface environments. Here, we quantify BPA oxidation rates and the formation of its predominant product, 4-hydroxycumyl alcohol (HCA), in tandem with transformation of a synthetic, Mn(III)-rich δ-MnO2. To investigate the effect of Mn oxide structural changes on BPA oxidation rate, twelve sequential additions of 80 μM BPA are performed at pH 7...
April 26, 2017: Environmental Science & Technology
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