Campbell method

D. P. Wilkinson, M. C. Johnson, K. M. Colbow, and S. A. Campbell. Method and apparatus for reducing reactant crossover in a liquid feed electrochemical fuel cell. US Patent 5874182 (1999). 

Polyphenylene sulfide is an important electronic polymer and can be synthesized using /7-dichlorobenzene with Na2S in n-pyrolidone (Campbell method). Its initiation step is as follows ... 

This approximation is a special case of the Baker-Campbell-Hausdorff lemma for additional discu.ssion and extensions to more general classes of methods. 

Although XRF is generally the X-ray spectrometry method of choice for analysis of major and trace elements in bulk specimens, useful PIXE measurements can be made. A detailed review of the main considerations for thick-target PEXE provides guidance for trace analysis with known and unknown matrices and bulk analysis when the constituents are unknown. Campbell and Cookson also discuss the increased importance of secondary fluorescence and geometrical accuracy for bulk measurements. 

Because physiological deterioration is generally accompanied by an increase in bacterial population, as pointed out by Nielsen, Wolford, and Campbell (33), estimation of bacterial numbers might serve as the basis of a test for condition. Obviously, the plate count method is not adaptable because of the time limitations imposed. Direct microscopic count would be much more appropriate, especially if a positive field count were substituted for cell count as suggested by Wolford (39). 

Roberts et al. (198 7) and Muller and Campbell (1990) used slightly different methods to extract and purify pholasin. They used lOmM ascorbate, instead of diethyldithiocarbamate, to inhibit luciferase in the process of extraction and purification, which enabled them to obtain the purified preparations of both pholasin and the luciferase. 

Minute amounts of coelenterazine can also be measured utilizing apoaequorin or apoobelin (Campbell and Herring, 1990 Thompson et ah, 1995). In this method, a sample containing coelenterazine is treated with an excess amount of apophotoprotein (apoaequorin or apoobelin) to convert it to a Ca2+-sensitive photoprotein (aequorin or obelin). The photoprotein formed is assayed by luminescing it with Ca2+ to determine the amount of coelenterazine originally existed. With this method, the luminescence reaction is fast and usually complete in a few seconds, in contrast to the slower luminescence reactions with luciferases that sometimes require a few minutes to complete. However, the formation of photoprotein from apoaequorin is slow and not necessarily quantitative, and the overall accuracy of the photoprotein method does not compare favorably with that of the luciferase method that directly measures coelenterazine. The author recommends using a luciferase if the enzyme is available. 

Carbodiimides have been prepared by desulfurization of thioureas by metal oxides, by sodium hypochlorite,4 or by ethyl chloroformate in the presence of a tertiary amine by halogena-tion of ureas or thioureas followed by dehydrohalogenation of the N,N -disubstituted carbamic chloride 8 and by dehydration of disubstituted ureas using -toluenesulfonyl chloride and pyridine.7 The method described above is a modification of that of Campbell and Verbanc. ... 

W. R. Sorensen and T. W. Campbell, Preparative Methods of Polymer Chemistry, Wiley-Interscience, New York, 1961, p. 74. 

Sorenson, W. R., Campbell, T. W. Preparative methods of polymer chemistry. 2nd edit New York Wiley 1968... 

C. D. Campbell, S. J. Grayston, and D. J. Hurst, Use of rhizosphere carbon sources in sole carbon source tests to discriminate soil microbial communities, J. Microh. Methods 50 33 (1997). 

M. M. Wong, R. E. Campbell, D. C. Fleck and D. H. Baker Jr., Electrolytic Methods of Preparing Cell Feed for Electrorefining Titanium, U. S. Bureau of Mines, Rept. Invst. No. 6161,1963. 

As mosquito larvae are relatively easy to kill with insecticides, any toxic spray residue is likely to be detected. Two species of mosquito larvae were used, the yellow fever mosquito (Aedes aegypti L.) and the southern house mosquito (Culex quinquefasdatus Say). Tests with the southern house mosquito were made essentially according to the method of Campbell, Sullivan, and Smith (I), except for the kind of food supplied and size of containers used. 

PPII helix-forming propensities have been measured by Kelly et al. (2001) and A. L. Rucker, M. N. Campbell, and T. P. Creamer (unpublished results). In the simulations the peptide backbone was constrained to be in the PPII conformation, defined as (0,VO = ( — 75 25°, +145 25°), using constraint potentials described previously (Yun and Hermans, 1991 Creamer and Rose, 1994). The AMBER/ OPLS potential (Jorgensen and Tirado-Rives, 1988 Jorgensen and Severance, 1990) was employed at a temperature of 298° K, with solvent treated as a dielectric continuum of s = 78. After an initial equilibration period of 1 x 104 cycles, simulations were run for 2 x 106 cycles. Each cycle consisted of a number of attempted rotations about dihedrals equal to the total number of rotatable bonds in the peptide. Conformations were saved for analysis every 100 cycles. Solvent-accessible surface areas were calculated using the method of Richmond (1984) and a probe of 1.40 A radius. 

Turek, J.W., Kang, C.H., Campbell, J.E., Americ, S.P., Sullivan, J.P. A sensitive technique for the detection of the alpha 7 neuronal nicotinic acetylcholine receptor antagonist, methyllycaconitine, in rat plasma and brain. J. Neurosci. Methods. 61 113, 1995. 

This equation must be solved for yn +l. The Newton-Raphson method can be used, and if convergence is not achieved within a few iterations, the time step can be reduced and the step repeated. In actuality, the higher-order backward-difference Gear methods are used in DASSL [Ascher, U. M., and L. R. Petzold, Computer Methods for Ordinary Differential Equations and Differential-Algebraic Equations, SIAM, Philadelphia (1998) and Brenan, K. E., S. L. Campbell, and L. R. Petzold, Numerical Solution of Initial-Value Problems in Differential-Algebraic Equations, North Holland Elsevier (1989)]. 

Campbell and Ottaway [136] also used selective volatilisation of the cadmium analyte to determine cadmium in seawater. They could detect 0.04 pg/1 cadmium (2pg in 50 pi) in seawater. They dried at 100 °C and atomised at 1500 °C with no char step. Cadmium was lost above 350 °C. They could not use ammonium nitrate because the char temperature required to remove the ammonium nitrate also volatilised the cadmium. Sodium nitrate and sodium and magnesium chloride salts provided reduced signals for cadmium at much lower concentrations than their concentration in seawater if the atomisation temperature was in excess of 1800 °C. The determination required lower atomisation temperatures to avoid atomising the salts. Even this left the magnesium interference, which required the method of additions. 

Campbell and Ottaway [672] have described a simple and rapid method for the determination of cadmium and zinc in seawater, using atomic absorption spectrometry with carbon furnace atomisation. Samples, diluted 1 + 1 with deionised water, are injected into the carbon furnace and atomised in an HGA-72 furnace atomiser under gas-stop conditions. A low atomisation temperature... 

Stoker, P.W., M.R. Plasterer, R.L. McDowell, R. Campbell, S. Fields, R. Price, C. Muehle, W.R. West, G.M. Both, J.R. Larsen, and M.L. Lee. 1984. Effects of coal-derived tars on selected aquatic and mammalian organisms. Pages 1239-1257 in M. Cooke and A.J. Dennis (eds.). Polynuclear Aromatic Hydrocarbons Mechanisms, Methods and Metabolism. Battelle Press, Columbus, OH. 

Shumaker Parry, J. S. Campbell, C. T., Quantitative methods for spatially resolved adsorption/desorption measurements in real time by surface plasmon resonance microscopy, Anal. Chem. 2004, 76, 907 917... 

---