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911.
A large amount of inedible plant material, generated as a result of plant growth in a Controlled Ecological Life Support System
(CELSS), should be pretreated and converted into forms that can be recycled on earth as well as in space. The main portion
of the inedible biomass is lignocellulosic material. Enzymatic hydrolysis of this cellulose would provide sugars for many
other uses by recycling carbon, hydrogen, oxygen, and nitrogen through formation of carbon dioxide, heat, and sugars, which
are potential foodstuffs. To obtain monosaccharides from cellulose, the protective effect of lignin should be removed. White-rot
fungi degrade lignin more extensively and rapidly than other microorganisms.Pleurotus ostreatus degrades lignin effectively, and produces edible and flavorful mushrooms that increase the quality and nutritional value
of the diet. This mushroom is also capable of metabolizing hemicellulose, thereby providing a food use of this pentose containing
polysaccharide. This study presents the current knowledge of physiology and biochemistry of primary and secondary metabolisms
of basidiomycetes, and degradation mechanism of lignin. A better understanding of the ligninolytic activity of white-rot fungi
will impact the CELSS Program by providing insights on how edible fungi might be used to recycle the inedible portions of
the crops. 相似文献
912.
Michael P. Scannell Syun-Ru Yeh Daniel E. Falvey 《Photochemistry and photobiology》1996,64(5):764-768
Abstract— The enzyme DNA photolyase mediates the repair of pyrimidine dimers. This repair step, a net retro [2 +2] reaction, proceeds through either the cation or anion radical of the pyrimidine dimer. In order to understand how electron transfer makes the repair process possible, its energetics have been examined by photothermal beam deflection calorimetry, fluorescence quenching and quantum yield studies. The enthalpy for the cleavage reaction of cis-syn 1,3-dimethylthymine dimer itself was found to be -19 kcal/mol. In addition, from the redox potentials, the enthalpies for the cleavage reactions of the dimer cation radical and the anion radical were determined to be -19 kcal/mol and -28 kcal/mol, respectively. 相似文献
913.
Frequency responses associated with adsorption of gas-phase toluene, o-nitrotoluene, valproic acid and the pesticides parathion, malathion and disulfoton on uncoated and protein-coated piezoelectric sensors are reported. Valproic acid antiserum and antibody against parathion were included among the set of protein films studied. Responses, which were reversible in all cases, are attributed to chemisorption or physisorption on electrode and protein surfaces. Under the conditions used, no signals corresponding to selective immunochemical binding were found. Highly sensitive responses of protein-coated sensors to the pesticide species were confirmed, with the lower limit of detection being about 0.01 μg l?1 in nitrogen carrier gas. 相似文献
914.
Chris J. Adams Michael I. Bruce Brian W. Skelton Allan H. White 《Journal of Cluster Science》1994,5(3):419-441
The reactions between Ru5(
5-C2PPh2)(gm-PPh2(CO)13 (1) and cyclopentadienes afforded the hexanuclear clusters Ru6(
6-C)(
3-PPh2)2(CO)10(-C5
R
5) [R
5 = H5 (2), H4Me (3), Me5 (4)] which contain an encapsulated carbide and a face-capping
3-CH group, formed by cleavage of CC and CP bonds of the C2PPh2 moiety in1. In the reaction with cyclopentadiene, the unusual ligand C13H12O, formed by combination of C2, CO and two molecules of C5H6 (or one molecule of dicyclopentadien), was characterized in the complex Ru5(
4-PPh) (
4-C13H12O)(-PPh2(CO)11(-C5H5) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru5(
3-CCHPh)(
4-PPh)(
4-PPh) (-PPh2)(CO)9(-C5Me5) (6) was also formed. 相似文献
915.
Ni/SiO2 exhibits higher activity for CO dissociation than coprecipitated Na–Mn–Ni, which is a higher oxygenate synthesis catalyst at 303 K, while Na–Mn–Ni exhibited higher CO dissociation activities at 673 K. 相似文献
916.
Michael H. Abraham Angela F. Danil de Namor Ronald A. Schulz 《Journal of solution chemistry》1977,6(8):491-500
Heats of solution of 13 11 electrolytes in 1-propanol have been determined calorimetrically at various electrolyte concentrations, and extrapolated to zero concentration to give H
s
o
values for these electrolytes. Together with literature data on three additional 11 electrolytes, these measurements yield a self-consistent set of single-ion enthalpies of transfer from water to 1-propanol. Values are tabulated for 10 univalent cations and five univalent anions. It is shown that the H
t
o
(Ph
4
As+)=H
t
o
(Ph
4
B–) assumption yields chemically reasonable single-ion values. Using this assumption, it may be deduced that all the univalent ions studied have about the same enthalpy in 1-propanol as in methanol. 相似文献
917.
Moilanen DE Piletic IR Fayer MD 《The journal of physical chemistry. C, Nanomaterials and interfaces》2007,111(25):8884-8891
The complex environments experienced by water molecules in the hydrophilic channels of Nafion membranes are studied by ultrafast infrared pump-probe spectroscopy. A wavelength dependent study of the vibrational lifetime of the O-D stretch of dilute HOD in H(2)O confined in Nafion membranes provides evidence of two distinct ensembles of water molecules. While only two ensembles are present at each level of membrane hydration studied, the characteristics of the two ensembles change as the water content of the membrane changes. Time dependent anisotropy measurements show that the orientational motions of water molecules in Nafion membranes are significantly slower than in bulk water and that lower hydration levels result in slower orientational relaxation. Initial wavelength dependent results for the anisotropy show no clear variation in the time scale for orientational motion across a broad range of frequencies. The anisotropy decay is analyzed using a model based on restricted orientational diffusion within a hydrogen bond configuration followed by total reorientation through jump diffusion. 相似文献
918.
919.
Hanna C. Wentz Grigorii Skorupskii Ana B. Bonfim Jenna L. Mancuso Christopher H. Hendon Evan H. Oriel Graham T. Sazama Michael G. Campbell 《Chemical science》2020,11(5):1342
Redox-active metal–organic frameworks (MOFs) are promising materials for a number of next-generation technologies, and recent work has shown that redox manipulation can dramatically enhance electrical conductivity in MOFs. However, ligand-based strategies for controlling conductivity remain under-developed, particularly those that make use of reversible redox processes. Here we report the first use of ligand n-doping to engender electrical conductivity in a porous 3D MOF, leading to tunable conductivity values that span over six orders of magnitude. Moreover, this work represents the first example of redox switching leading to reversible conductivity changes in a 3D MOF.Redox-active ligands are used to reversibly tune electrical conductivity in a porous 3D metal–organic framework (MOF). 相似文献
920.
Lei Liu Wes Lee Cassandra R. Youshaw Mingbin Yuan Michael B. Geherty Peter Y. Zavalij Osvaldo Gutierrez 《Chemical science》2020,11(31):8301
A highly chemoselective iron-catalyzed three-component dicarbofunctionalization of unactivated olefins with alkyl halides (iodides and bromides) and sp2-hybridized Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles (electron-rich and electron-deficient (hetero)aryl and alkenyl Grignard reagents), alkyl halides (tertiary alkyl iodides/bromides and perfluorinated bromides), and unactivated olefins bearing diverse functional groups including tethered alkenes, ethers, protected alcohols, aldehydes, and amines to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C–C bonds.A highly selective iron-catalyzed three-component dicarbofunctionalization of unactivated alkenes with alkyl halides and sp2-hybridized Grignard reagents is reported. 相似文献