Abstract  Aldehyde-deformylating oxygenase (ADO) catalyzes O2-dependent release of the terminal carbon of a biological substrate, octadecanal, to yield formate and heptadecane in a reaction that requires external reducing equivalents. We show here that ADO also catalyzes incorporation of an oxygen atom from O2 into the alkane product to yield alcohol and aldehyde products. Oxygenation of the alkane product is much more pronounced with C9-10 aldehyde substrates, so that use of nonanal as the substrate yields similar amounts of octane, octanal, and octanol products. When using doubly-labeled [1,2-(13)C]-octanal as the substrate, the heptane, heptanal and heptanol products each contained a single (13)C-label in the C-1 carbons atoms. The only one-carbon product identified was formate. [(18)O]-O2 incorporation studies demonstrated formation of [(18)O]-alcohol product, but rapid solvent exchange prevented similar determination for the aldehyde product. Addition of [1-(13)C]-nonanol with decanal as the substrate at the outset of the reaction resulted in formation of [1-(13)C]-nonanal. No (13)C-product was formed in the absence of decanal. ADO contains an oxygen-bridged dinuclear iron cluster. The observation of alcohol and aldehyde products derived from the initially formed alkane product suggests a reactive species similar to that formed by methane monooxygenase (MMO) and other members of the bacterial multicomponent monooxygenase family. Accordingly, characterization by EPR and Mössbauer spectroscopies shows that the electronic structure of the ADO cluster is similar, but not identical, to that of MMO hydroxylase component. In particular, the two irons of ADO reside in nearly identical environments in both the oxidized and fully reduced states, whereas those of MMOH show distinct differences. These favorable characteristics of the iron sites allow a comprehensive determination of the spin Hamiltonian parameters describing the electronic state of the diferrous cluster for the first time for any biological system. The nature of the diiron cluster and the newly recognized products from ADO catalysis hold implications for the mechanism of C-C bond cleavage.

Abstract  Using a strongly polar cyanopropyl capillary column we have investigated the gas chromatography (GC) separation behaviors of 24 octadecadienoic acid methyl ester (18:2ME) isomers compared against saturated methyl stearate (18:0ME) and arachidic acid methyl ester (20:0ME), and the dependency on the GC column temperature. The 24 isomers were obtained by performing cis-to trans-isomerization of six regioisomers: five of the 18:2ME isomers were prepared by the partial reduction of methyl α-linolenate and methyl γ-linolenate C18 trienoic acids with different double bond positions, whereas the sixth isomer, 18:2ME (c5, c9), was obtained from a raw constituent fatty acid methyl ester (FAME) sample extracted from Japanese yew seeds. There are no reference standards commercially available for 18:2ME isomers, and in elucidating the elution order of these isomers this study should help the future identification of cis- and trans-type of 18:2ME. We also report the identification method of cis- and trans-type of FAME using equivalent chain lengths and attempt the identification of cis- and trans-type of 18:2ME isomers from partially hydrogenated canola oil.

Abstract  Structural characteristics of benzene-ethanol-extracted lignin (BEL) and acetone-extracted lignin (AL) precipitated from black liquor were identified by elemental analysis, FTIR, (13)C NMR, and (1)H NMR, while the thermal behaviors were examined with thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR). The frequency of β-O-4 bonds per 100 C9 monomeric units was 28 and 17 for BEL and AL. Two-stage pyrolysis processes were observed for the two lignins. The mass loss rate of the initial solvent evolution stage (110-180 °C) of BEL was greater than that of AL. The two lignins presented slightly different mass loss curves and evolution profiles of gases in the main pyrolysis stage (280-500 °C). A global kinetic model was proposed for lignin pyrolysis and activation energies of 39.5 and 38.8 kJ/mol was obtained for BEL and AL. The results enhance understanding of lignin pyrolysis and facilitate commercial utilization of black-liquor lignin.

Abstract  Purification of 278 tons of liquid scintillator and 889 tons of buffer shielding for the Borexino solar neutrino detector is performed with a system of combined distillation, water extraction, gas stripping and filtration. The purification system removed K, U and Th by distillation of the pseudocumene solvent and the PPO fluor. Noble gases, Rn, Kr and Ar were removed by gas stripping. Distillation was also employed to remove optical impurities and reduce the attenuation of scintillation light. The success of the purification system has facilitated the first time real time detection of low energy solar neutrinos.

Abstract  Mesoporous titanium-silicates have been prepared following the evaporation-induced self-assembly (EISA) methodology and characterized by elemental analysis, XRD, N-2 adsorption, SEM, DRS UV-Vis and Raman techniques. The use of acetylacetone during synthesis allowed the formation of highly dispersed dimeric and/or small oligomeric Ti species, within the mesostructured silica network, to be realized. The materials catalyse oxidation of alkylsubstituted phenols to corresponding p-benzoquinones with 100% selectivity using the green oxidant - 30% aqueous hydrogen peroxide. The titanium-silicates prepared by the convenient and versatile EISA-based procedure reveal the true heterogeneous nature of the catalysis and do not suffer from titanium leaching. They show advantages over other types of mesoporous Ti, Si-catalysts, such as TiO2-SiO2 mixed oxides and grafted Ti/SiO2, in terms of the catalyst stability and reusability.

Abstract  Ultrasmall FeRu bimetallic nanoparticles were prepared by co-decomposition of two organometallic precursors, {Fe[N(Si(CH3)(3))(2)](2)}(2) and (eta(4)-1,5-cyclooctadiene)(eta(6)-1,3,5-cyclooctatriene)ruthenium(0) (Ru(COD)(COT)), under dihydrogen at 150 degrees C in mesitylene. A series of FeRu nanoparticles of sizes of approximately 1.8 nm and incorporating different ratios of iron to ruthenium were synthesized by varying the quantity of the ruthenium complex introduced (Fe/Ru = 1:1, 1:0.5, 1:0.2, and 1:0.1). FeRu nanoparticles were characterized by TEM, high-resolution TEM, and wide-angle X-ray scattering analyses. Their surface was studied by hydride titration and IR spectroscopy after CO adsorption and their magnetic properties were analyzed by using a superconducting quantum interference device (SQUID). The FeRu nanoparticles were used as catalysts in the hydrogenation of styrene and 2-butanone. The results indicate that the selectivity of the nanoparticle catalysts can be modulated according to their composition and therefore represent a case study on fine-tuning the reactivity of nanocatalysts and adjusting their selectivity in a given reaction.

Abstract  Monodisperse Au-Ag alloy nanoparticles of different compositions are prepared through the mild decomposition of the bimetallic precursor [Au2Ag2(C6F5)(4)(OEt2)(2)](n) in an organic solvent using hexadecylamine (HDA) as a stabilizing ligand. The effects of different reaction parameters on the size and composition of the nanoparticles, such as the metal : HDA ratio, the use of H-2 reducing gas or the solvent (toluene, THF or mesitylene), have been studied through TEM, HRTEM, EDS, UV/Vis and F-19 NMR spectroscopy. The localized surface plasmon resonance (LSPR) displayed by the spherical Au-Ag nanoparticles can be tuned as a function of the metal composition.

Abstract  Selective photocatalytic oxygenation of various substrates has been achieved using organic photocatalysts via photoinduced electron-transfer reactions of photocatalysts with substrates and dioxygen under visible light irradiation. Photoinduced electron transfer from benzene to the singlet-excited state of the 3-cyano-1-methylquinolinium ion has enabled the oxidation of benzene by dioxygen with water to yield phenol selectively. Alkoxybenzenes were obtained when water was replaced by alcohols under otherwise the same experimental conditions. Photocatalytic selective oxygenation reactions of aromatic compounds have also been achieved using an electron donor-acceptor linked dyad, 9-mesityl-10-methylacridinium ion (Acr(+)-Mes) acting as a photocatalyst and dioxygen as an oxidant under visible light irradiation. The oxygenation reaction is initiated by intramolecular photoinduced electron transfer from the mesitylene moiety to the singlet-excited state of the acridinium moiety of Acr(+)-Mes to afford an extremely long-lived electron-transfer state. The electron-transfer state can oxidize and reduce substrates and dioxygen, respectively, leading to selective oxygenation and halogenation of substrates. C-C bond formation of substrates has also been made possible by using Acr(+)-Mes as a photocatalyst.

Abstract  In the actinorhodin type II polyketide synthase, the first polyketide modification is a regiospecific C9-carbonyl reduction, catalyzed by the ketoreductase (actKR). Our previous studies identified the actKR 94-PGG-96 motif as a determinant of stereospecificity. The molecular basis for reduction regiospecificity is, however, not well understood. In this study, we examined the activities of 20 actKR mutants through a combination of kinetic studies, PKS reconstitution, and structural analyses. Residues have been identified that are necessary for substrate interaction, and these observations have suggested a structural model for this reaction. Polyketides dock at the KR surface and are steered into the enzyme pocket where C7-C12 cyclization is mediated by the KR before C9-ketoreduction can occur. These molecular features can potentially serve as engineering targets for the biosynthesis of novel, reduced polyketides.

Abstract  The characteristics of oxygen-enriched liquid scintillators with very low afterglow are investigated and optimized for application to a single-hit neutron spectrometer for fast ignition experiments. It is found that 1,2,4-trimethylbenzene has better characteristics as a liquid scintillator solvent than the conventional solvent, p-xylene. In addition, a benzophenon-doped BBQ liquid scintillator is shown to demonstrate very rapid time response, and therefore has potential for further use in neutron diagnostics with fast time resolution. (C) 2014 AIP Publishing LLC.

Abstract  We show that heteronuclear decoupling during symmetry-based C9 TOBSY sequences can be improved by using phase-alternating pulse sequences (XiX) instead of cw irradiation. The use of XiX sequences makes the optimization of the decoupling rf-field amplitude simpler and lowers the decoupling rf-field requirements to attain a comparable performance. A Floquet analysis of the first-order resonance conditions was used to determine the correct timing of the XiX sequence to avoid interference between the C sequence and the decoupling. The decoupling performance is analyzed analytically using Floquet theory and verified using numerical simulations as well as experimental results.

Abstract  Solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy was performed to analyze two fluorinated steroids, i.e., betamethasone (BMS) and fludrocortisone acetate (FCA), that have fluorine attached to C9, as well as two non-fluorinated analogs, i.e., prednisolone (PRD) and hydrocortisone 21-acetate (HCA). The (13)C signals of BMS revealed multiplet patterns with splittings of 16-215Hz, indicating multiple ring conformations, whereas the (13)C signals of FCA, HCA, and PRD exhibited only singlet patterns, implying a unique conformation. In addition, BMS and FCA exhibited substantial deviation (>3.5ppm) in approximately half of the (13)C signals and significant deviation (>45ppm) in the (13)C9 signal compared to PRD and HCA, respectively. In this study, we demonstrate that fluorinated steroids, such as BMS and FCA, have steroidal ring conformation(s) that are distinct from non-fluorinated analogs, such as PRD and HCA.

Abstract  Batch, modified semi-continuous and continuous cultivations of Chlorella vulgaris C9-JN 2010 cells in municipal effluent were performed and analyzed. The experiments were carried out in 7.5-L photo-bioreactors, to which 2% of CO2 was supplied. Biomass and specific growth rate of C. vulgaris were 0.528-0.760gl(-1) and 0.200-0.374d(-1), respectively. Meanwhile, it could efficiently remove ammonia-N, total nitrogen, total phosphorus, CODCr and BOD5 by around 98.0%, 90.9-93.6%, 89.9-91.8%, 60.7-90.0% and 83.4-88.4%, respectively. Algal protein content was 550±30.0mgg(-1) of the harvested biomass of C. vulgaris which was rich in eight kinds of essential amino acids (around 44.5% of the total). The processes of cultivation of C. vulgaris in municipal effluent could be proposed as dual-beneficial approaches, which could produce profitable byproducts and simultaneously reduce the contaminations to environment.

Abstract  Design and synthesis of effective heterogeneous catalysts for the conversion of biomass intermediates into long chain hydrocarbon precursors and their subsequent deoxygenation to hydrocarbons is a viable strategy for upgrading lignocellulose into distillate range drop-in biofuels. Herein, we report a two-step process for upgrading 5-hydroxymethylfurfural (HMF) to C9 and C11 fuels with high yield and selectivity. The first step involves aldol condensation of HMF and acetone with a water tolerant solid base catalyst, zirconium carbonate (Zr(CO3 )x ), which gave 92 % C9 -aldol product with high selectivity at nearly 100 % HMF conversion. The as-synthesised Zr(CO3 )x was analysed by several analytical methods for elucidating its structural properties. Recyclability studies of Zr(CO3 )x revealed a negligible loss of its activity after five consecutive cycles over 120 h of operation. Isolated aldol product from the first step was hydrodeoxygenated with a bifunctional Pd/Zeolite-β catalyst in ethanol, which showed quantitative conversion of the aldol product to n-nonane and 1-ethoxynonane with 40 and 56 % selectivity, respectively. 1-Ethoxynonane, a low oxygenate diesel range fuel, which we report for the first time in this paper, is believed to form through etherification of the hydroxymethyl group of the aldol product with ethanol followed by opening of the furan ring and hydrodeoxygenation of the ether intermediate.

Abstract  The recent volatility in oil prices has fueled uncertainty about the world's ability to meet future demands. Furthermore, the growing concern over the negative environmental impacts produced by emissions has resulted in worldwide efforts for developing renewable jet-fuel alternatives. This has led current military and civilian fuel specifications to allow the use of Fischer-Tropsch (FT) and Hydroprocessed fuels (HEFA) in blends up to 50% in volume with regular Jet-A/JP-8. On the other hand, physical properties, and the broad chemical composition, including trace elements in those fuels, may result in engine performance issues found only after extensive operation. This may result in higher maintenance and operation costs. This study presents the coking depositions of several renewable fuels after being stressed in a fixed bed reactor. This was done in an effort to assess the effects (if any) on the thermal stability of renewable fuels interacting with materials representative of state of the art aircraft systems (steel, aluminum, titanium tubing) and to determine whether the use of renewable fuels enhances thermal stability when blended, up to 50%, with oil-derived fuels.

Abstract  Large oil spills and oily wastewater discharges from ships and industrial activities can have serious impacts on the environment with potentially major economic impacts. Current oil remediation techniques are inefficient and may have deleterious environmental consequences. However, nanotechnology offers a new route to potentially remediate oil pollution. In this study, a cheap and facile hydrothermal method was developed to synthesize polyvinylpyrrolidone-coated magnetite nanoparticles to separate a reference MC252 oil from oil-water mixture under environmentally relevant conditions. Fluorescence and Proton nuclear magnetic resonance spectroscopy results showed near 100% oil removal from oil-water mixture in the ultrapure water under optimum condition. Based on gas chromatography-mass spectrometry data, approximately 100% of lower molecular mass alkanes (C9-C21) were removed within 10 min of magnetic separation and by increasing the separation time to 40 min, greater than 67% of C22-25 alkanes were removed. Moreover, nanoparticles removed near 100% oil from synthetic seawater solutions in the presence and absence of fulvic acid showing excellent oil removal capacity of the nanoparticles under different conditions. Results show that these nanoparticles can be utilized to remove oil over a short time with a high removal efficiency under environmentally relevant conditions.

Abstract  The article presents the test results of an engine operating with diesel fuel (B5), turbine type JP-8 fuel and its 5 vol%, 10 vol%, 20 vol%, and 30 vol% blends with rapeseed oil methyl ester (RME). Additional fuel blend B10 was prepared by pouring 10 vol% of RME to diesel fuel to extend interpretation of the test results. The purpose of this study was to examine the effects of using jet-biodiesel fuel blends J5, J10, J20, J30, and B10 on the start of injection, ignition delay, combustion history, heat release, engine performance, and exhaust emissions. The engine performance parameters were examined at light 15% (1400 rpm) and 10% (2200 rpm), medium 50%, and high 100% loads and the two speeds: 1400 rpm at which maximum torque occurs and a rated speed of 2200 rpm. The autoignition delay and maximum heat release rate decreased, maximum cylinder pressure, and pressure gradients increased, whereas brake specific fuel consumption changed little and brake thermal efficiency was 1.0-3.6% higher when running with fuel blends J5 to J30 at rated speed compared with the data measured with neat jet fuel. The NOx emissions increased slightly, but the CO, THC emissions, and smoke opacity boosted up significantly when using jet fuel blend J10 with a smooth reduction of unburned hydrocarbons for jet-biodiesel fuel blends with higher CN ratings. Operation at a full (100%) load with fuel blend J10 produced more CO and exhaust smoke, whereas the combustion of identical fuel blend B10 showed the reverse trends reducing both pollutants at both engine speeds. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract  A new trinuclear zinc complex Zn-3(2,2'-biPY)(2)(3,5-DMBA)(6).(H2O)1,5 (1) with 3,5-dimethylbenzoic acid (3,5-DMBA) and 2,2'-bipyridine as ligands has been synthesized in the mixed solvents of methanol and water. It crystallizes in the monoclinic space group C2/c with a = 31.1497(15), b = 11.7576(6), c = 20.9049(10) A, = 118.4550(10), V = 6731.4(6) angstrom(3), D-c, = 1.412 g/cm(3), Z = 4, F(000) = 2972, GOOF = 1.069, the final R= 0.0667 and wR= 0.1917. The whole molecule consists of three zinc ions, six 3,5-DMBA molecules, two 2,2'-bipyridine molecules and one and half water molecules, in which three zinc ions are bridged by six mu(2)-eta(1):eta(0)-carboxylate groups of 3,5-DMBA". The Zn(1) atom is centrosymmetric, and adopts a distorted octahedral ZnO6 geometry, while the Zn(2) gives a distorted square pyramidal ZnO3N2 geometry. The spectroscopic characterization and thermal stability properties of the complex were investigated.

Abstract  Fluorescent probes enable detection of otherwise nonfluorescent species via highly sensitive laser-induced fluorescence. Organic amines are predominantly nonfluorescent and are of analytical interest in agricultural and food science, biomedical applications, and biowarfare detection. Alexa Fluor 488 N-hydroxysuccinimidyl ester (AF488 NHS-ester) is an amine-specific fluorescent probe. Here, we demonstrate low limit of detection of long-chain (C9 to C18) primary amines and optimize AF488 derivatization of long-chain primary amines. The reaction was found to be equally efficient in all solvents studied (dimethylsulfoxide, ethanol, and N,N-dimethylformamide). While an organic base (N,N-diisopropylethylamine) is required to achieve efficient reaction between AF488 NHS-ester and organic amines with longer hydrophobic chains, high concentrations (>5 mM) result in increased levels of ethylamine and propylamine in the blank. Optimal incubation times were found to be >12 hrs at room temperature. We present an initial capillary electrophoresis separation for analysis using a simple micellar electrokinetic chromatography (MEKC) buffer consisting of 12 mM sodium dodecylsulfate (SDS) and 5 mM carbonate, pH 10. Limits of detection using the optimized labeling conditions and these separation conditions were 5-17 nM. The method presented here represents a novel addition to the arsenal of fluorescent probes available for highly sensitive analysis of small organic molecules.

Abstract  We examined how the stereo-configurational difference affects the reaction of a carbohydrate model compound with active oxygen species (AOS) generated in situ by reactions between O-2 and a phenolic compound under conditions similar to those of oxygen delignification or with oxyl anion radical, the conjugate base of hydroxyl radical, generated by the decomposition of H2O2 under alkaline conditions. As the phenolic compound, 2,4,6-trimethylphenol or 4-hydroxy-3-methoxybenzyl alcohol (vanillyl alcohol) was used. The carbohydrate model compounds employed were methyl beta-d-glucopyranoside (MGP beta) and its 4 epimers, methyl alpha-d-glucopyranoside (MGP alpha), methyl beta-d-mannopyranoside (MMP), methyl beta-d-allopyranoside (MAP), and methyl beta-d-galactopyranoside (MGaP). Their stabilities were in the order of MGP alpha > MGP beta > MMP > MGaP > MAP, indicating that the reactivity of the carbohydrate model compound is significantly dependent on where the stereo-configurational difference is. Only the co-existence of MMP enhanced the degradation of MGP beta, when a pair of MGP beta and another carbohydrate model compound was reacted with the AOS. This result suggests that the profile of AOS in the system is dependent not only on the type of phenolic compound, the generator of AOS, but also on that of the carbohydrate model compound.

Abstract  In this research, the effects of EGR (exhaust gas recirculation) and multiple injection strategy with two pilots on the emissions and combustion characteristics of JP-8 fueled light-duty diesel engine were systemically investigated. Also, the potential of reducing NOx (nitrogen oxides) and PM (particulate matter) emissions with JP-8 in a light-duty diesel engine was evaluated. To understand the combustion phenomenon of JP-8, two different injection modes (single injection and multiple injection with two pilots) were applied. Under the single injection mode, the difference in the ignition delay between using JP-8 and diesel fuel became clear. Differently, under multiple injections with two pilots, the ignition delays of both cases were nearly the same due to the higher in the cylinder temperature cause by the combustion of the pilot injections. Finally, under multiple injection mode, more EGR (exhaust gas recirculation) could be applied to JP-8 combustion than in conventional diesel combustion while maintaining the same mass fraction burned 50% (MFB 50) to attain the same fuel conversion efficiency. As a result, NOx and PM emissions could be reduced by half when using JP-8 without decreasing the fuel conversion efficiency. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract  Diacylglycerol lipase α (DAGLα) is responsible for the formation of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the central nervous system. DAGLα inhibitors are required to study the physiological role of 2-AG. Previously, we identified the α-ketoheterocycles as potent and highly selective DAGLα inhibitors. Here, we present the first comprehensive structure-activity relationship study of α-ketoheterocycles as DAGLα inhibitors. Our findings indicate that the active site of DAGLα is remarkably sensitive to the type of heterocyclic scaffold with oxazolo-4N-pyridines as the most active framework. We uncovered a fundamental substituent effect in which electron-withdrawing meta-oxazole substituents increased inhibitor potency. (C6-C9)-acyl chains with a distal phenyl group proved to be the most potent inhibitors. The integrated SAR data was consistent with the proposed binding pose in a DAGLα homology model. Altogether our results may guide the design of future DAGLα inhibitors as leads for molecular therapies to treat neuroinflammation, obesity and related metabolic disorders.

Abstract  Direct catalytic conversion of ethanol to hydrocarbon blend-stock can increase biofuels use in current vehicles beyond the ethanol blend-wall of 10-15%. Literature reports describe quantitative conversion of ethanol over zeolite catalysts but high C2 hydrocarbon formation renders this approach unsuitable for commercialization. Furthermore, the prior mechanistic studies suggested that ethanol conversion involves endothermic dehydration step. Here, we report the complete conversion of ethanol to hydrocarbons over InV-ZSM-5 without added hydrogen and which produces lower C2 (<13%) as compared to that over H-ZSM-5. Experiments with C2H5OD and in situ DRIFT suggest that most of the products come from the hydrocarbon pool type mechanism and dehydration step is not necessary. Thus, our method of direct conversion of ethanol offers a pathway to produce suitable hydrocarbon blend-stock that may be blended at a refinery to produce fuels such as gasoline, diesel, JP-8, and jet fuel, or produce commodity chemicals such as BTX.

Abstract  With current DoD goals of switching to a common logistics fuel, there is a significant drive to develop technologies that allow small, high power density engines such as used in unmanned aerial, marine, and ground vehicles, typically fueled by volatile fuels such as gasoline, to operate on heavy fuels such as JP-8. In this paper, the potential of advanced catalytic glow plugs as an enabling component for the use of heavy fuels both as a retrofit to existing engines as well as new engine designs is demonstrated. Compared to standard spark igniters and non-catalytic glow plugs, the use of catalytic glow plugs will provide benefits of lower required compression ratio, improved igniter life, reduced electrical energy requirements, and overall reduction in system weight and size. The advanced catalytic glow plug was demonstrated to have a significant increase in surface temperature (180+degrees C) with impingement of a fuel spray. Engine testing demonstrated that the use of catalyst allowed stable engine operation at reduced power requirements. This technology would allow high power density engines to use heavy fuels, while potentially reducing electric power supply and engine complexity and weight, both of which would allow greater range and/or payload capacity.