Acetylene-reducing activity of detached pea nodules was determined by submerging the nodules in buffer solution [tris(hydroxymethyl)aminomethane-hydrochloride, pH 7.4] containing 100 mM sodium succinate and incubating under a gas phase of 90% O(2) and 10% C(2)H(2). The nitrogenase activity was 4 to 8 mumol of C(2)H(4) formed per g of nodule fresh weight per h and remained constant for at least ...

An ultra-high vacuum experimental study of acetylene chemisorption on Pt(111) and Pt(100) and of the reaction of hydrogen with the acetylene adsorbate has established distinguishing features of carbon-hydrogen bond breaking and making processes as a function of pressure, temperature, and surface crystallography. The rates for both processes are substantially higher on the Pt(100) surface. Net a...

A simple model is proposed for calculating the reaction yield of a surface reaction of molecules chemisorbed on regular surfaces. An application to benzene from acetylene tricyclization on Pd(111) is performed. The analysis relies on random adsorption of acetylene on the clean crystal surface. The benzene yield is calculated in terms of the acetylene coverage. Analytical results are compared wi...

Cell-free extracts of Clostridiiumii p(lste'rtr'i lm il (8) aind( of A2otoboctcr viiell(tlfdii (2) in the presence of an ATP generating system alndI anl appropriate electron donior, catalvze the redcuction of N. gas to ammonia. In recent investigations (3,4, 9) of the properties of nitrogenase from these organiisms, it has been established that the enzyme system is non-specific for electron acc...

Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea. High NH4+ ion concentrations were protective. The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. If acetylene was added in the absence of O2, the cells remained active until O2 was re-introdu...

Non-adiabatic dynamics of the acetylene cation is investigated using mixed quantum-classical dynamics based on trajectory surface hopping. To describe the non-adiabatic effects, two surface hopping methods are used, namely, Tully's fewest switches and Landau-Zener surface hopping. Similarities and differences between the results based on those two methods are discussed. We find that the photoio...

Characterization of nodule growth and functioning, phosphorus status of plant tissues and hostplant growth of nodulated soybean (Glycine max L. Merr.) plants grown under different phosphorus conditions was studied in order to evaluate the role of phosphorus in symbiotic nitrogen fixation. Phosphorus deficiency treatment decreased the whole plant fresh and dry mass, nodule weight, number and fun...

Optimization of continuous synthesis of high purity carbon nanotubes (CNTs) using chemical vapour deposition (CVD) method was studied experimentally and theoretically. Iron pentacarbonyl (Fe(CO)5), acetylene (C2H2) and Ar were used as the catalyst source, carbon source and carrier gas respectively. The synthesis temperature and flow rates of Ar and acetylene were optimized to produce CNTs at a ...

In 1937, Wilson and Umbreit1 reported that H2 inhibited N2 fixation in red clover plants and when this inhibition proved to be competitive, it implied that N2 and H2 were bound at the same site on the enzyme. The enzyme also binds CO2 and N20' competitively with N2. The first evidence that any compound other than N2 bound at the N2-fixing site could be reduced was supplied when Mozen and Burris...