Ecological models based on physical, chemical, and biological processes are diicult to develop and calibrate. Neural network methods provide an attractive alternative where the model is constructed automatically. We compared the MAPSS global vegetation model to a collection of neural network models trained on a data set covering current climate and vegetation distribution in the coterminous Uni...

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to chang...

The purpose of this article is to expand the available knowledge on CO2 transfer across the gas/liquid interface in two ways: (1) propose a new mathematical model to describe the pH dependence of CO2 flux across the gas/liquid interface; and (2) propose new relationships that quantitatively describe the contributions of each of the carbonate species ( 3 2CO H , − 3 HCO , and − 2 3 CO ) to total...

Hydrogenase pleiotropically acting protein (Hyp)E plays a role in biosynthesis of the cyano groups for the NiFe(CN)2CO center of [NiFe] hydrogenases by catalyzing the ATP-dependent dehydration of the carbamoylated C-terminal cysteine of HypE to thiocyanate. Although structures of HypE proteins have been determined, until now there has been no structural evidence to explain how HypE dehydrates t...

Clostridium thermoaceticum was cultivated in glucose-limited media, and the dissimilation of CO to acetic acid was evaluated. We found that cultures catalyzed the rapid dissimilation of CO to acetic acid and CO(2), with the stoichiometry obtained for conversion approximating that predicted from the following reaction: 4CO + 2H(2)O --> CH(3)CO(2)H + 2CO(2). Growing cultures formed approximately ...

Co2(CO)8 has proved a key material for the preparation of a variety of cobalt carbonyl com­ plexes. Although most of its reactions involve oxi­ dation, reduction, disproportionation or substitu­ tion [2], addition reactions are scarce. Moreover, Co2(CO)8 is one of the few compounds to form ad­ dition products with strong Lewis acids such as AlBr3 [3]. The acid adds to the oxygen atom of a bridg...

High-performance liquid chromatography coupled to electrospray ionization (ESI) tandem mass spectrometry and photodiode array detection (HPLC-DAD-ESI-MS(n)) was developed to identify and characterize the flavonoids in a Chinese formulated preparation, Longdan Xiegan Decoction (LXD). In total, fifty-one flavonoids (27 flavones, 10 flavanones, 7 chalcones, 5 flavonols and 2 isoflavones) were char...

Reactions of Co(PMe3)3Cl or CoCl2 with 3,5-(CF3)2-PzNa in hexane give Co(PMe3)3(3,5-(CF3)2-Pz) (1) and Co(PMe3)3(3,5-(CF3)2-Pz)2 (2) respectively (3,5-(CF3)2-PzNa = sodium bis-trifluoromethylpyrazolate). Reaction of (3,5-(CF3)2-PzH) with Co(PMe3)4 produces the unusual complex [cis-Co(PMe3)4H2][Co(PMe3)(3,5-(CF3)2-Pz)3] (3) which formally contains a [Co(III)](+)[Co(II)](-) complex ion pair. Reac...

Friedel-Crafts alkylation of 4-tert-butylaniline with 2 equiv of benzhydrol affords bulky 2,6-bis(diphenylmethyl)-4-tert-butylaniline (Ar*NH2) in good yield, which can be readily synthesized on a tens of grams scale. The reaction of 6 equiv of Ar*NH2 with triphosgene generates the symmetric urea (Ar*NH)2CO, which, upon dehydration with a P2O5/Al2O3 slurry in pyridine, produces the sterically en...