Cozymase. A study of purification methods

Cozymase is one of the essential components of the complex enzyme mixture which effects alcoholic fermentation in the absence of living cells. The separation of the mixture into zymase and cozymase was first accomplished by Harden and Young [1] by means of ultrafiltration through a gelatin-impregnated Chamberland filter candle. The residue and filtrate as thus prepared possessed, separately, no fermentative action, but when mixed were found to produce a rapid fermentation. The active constituent of the residue was named zymase, while that constituent of the filtrate responsible for the reactivation of the residue was named cozymase. We studied the purification produced in our material by a variety of reagents. In the investigation we have repeated much of the work done by von Euler and Myrbäk [2], and several differences have been found, which appear difficult to explain solely upon the basis of the lower initial purity of our material. As certain of the experiments show distinct promise, we hope to be able to extend the work upon a material of considerably higher original purity, such as was employed by von Euler and Myrbäk

Experimental results for a two-dimensional supersonic inlet used as a thrust deflecting nozzle

Nearly all supersonic V/STOL aircraft concepts are dependent on the thrust deflecting capability of a nozzle. In one unique concept, referred to as the reverse flow dual fan, not only is there a thrust deflecting nozzle for the fan and core engine exit flow, but because of the way the propulsion system operates during vertical takeoff and landing, the supersonic inlet is also used as a thrust deflecting nozzle. This paper presents results of an experimental study to evaluate the performance of a supersonic inlet used as a thrust deflecting nozzle for this reverse flow dual fan concept. Results are presented in terms of nozzle thrust coefficient and thrust vector angle for a number of inlet/nozzle configurations. Flow visualization and nozzle exit flow survey results are also shown

Zinc abundances of planetary nebulae

Zinc is a useful surrogate element for measuring Fe/H as, unlike iron, it is not depleted in the gas phase media. Zn/H and O/Zn ratios have been derived using the [Zn IV] emission line at 3.625um for a sample of nine Galactic planetary nebulae, seven of which are based upon new observations using the VLT. Based on photoionization models, O/O++ is the most reliable ionisation correction factor for zinc that can readily be determined from optical emission lines, with an estimated accuracy of 10% or better for all targets in our sample. The majority of the sample is found to be sub-solar in [Zn/H]. [O/Zn] in half of the sample is found to be consistent with Solar within uncertainties, whereas the remaining half are enhanced in [O/Zn]. [Zn/H] and [O/Zn] as functions of Galactocentric distance have been investigated and there is little evidence to support a trend in either case.Comment: Accepted MNRAS, 11 pages, 8 figure

Bose-Einstein condensation in complex networks

The evolution of many complex systems, including the world wide web, business and citation networks is encoded in the dynamic web describing the interactions between the system's constituents. Despite their irreversible and non-equilibrium nature these networks follow Bose statistics and can undergo Bose-Einstein condensation. Addressing the dynamical properties of these non-equilibrium systems within the framework of equilibrium quantum gases predicts that the 'first-mover-advantage', 'fit-get-rich' and 'winner-takes-all' phenomena observed in competitive systems are thermodynamically distinct phases of the underlying evolving networks

The rise of the skilled city

For more than a century, educated cities have grown more quickly than comparable cities with less human capital. This fact survives a battery of other control variables, metropolitan area fixed effects, and tests for reverse causality. The authors also find that skilled cities are growing because they are becoming more economically productive (relative to less skilled cities), not because these cities are becoming more attractive places to live. Most surprisingly, the authors find evidence suggesting that the skills-city growth connection occurs mainly in declining areas and occurs in large part because skilled cities are better at adapting to economic shocks. As in Schultz (1964), skills appear to permit adaptationCities and towns

The Rise of the Skilled City

For more than a century, educated cities have grown more quickly than comparable cities with less human capital. This fact survives a battery of other control variables, metropolitan area fixed effects and tests for reverse causality. We also find that skilled cities are growing because they are becoming more economically productive (relative to less skilled cities), not because these cities are becoming more attractive places to live. Most surprisingly, we find evidence suggesting that the skills-city growth connection occurs mainly in declining areas and occurs in large part because skilled cities are better at adapting to economic shocks. As in Schultz (1964), skills appear to permit adaptation.

The Rise of the Skilled City

For more than a century, educated cities have grown more quickly than comparable cities with less human capital. This fact survives a battery of other control variables, metropolitan area fixed effects and tests for reverse causality. We also find that skilled cities are growing because they are becoming more economically productive (relative to less skilled cities), not because these cities are becoming more attractive places to live. Most surprisingly, we find evidence suggesting that the skills-city growth connection occurs mainly in declining areas and occurs in large part because skilled cities are better at adapting to economic shocks. As in Schultz (1964), skills appear to permit adaptation.

Three-dimensional negative index of refraction at optical frequencies by coupling plasmonic waveguides

We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. By properly controlling coupling between adjacent waveguides, a metamaterial consisting of a one-dimensional multilayer stack exhibiting an isotropic index of -1 can be achieved at a free-space wavelength of 400 nm. The general concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.Comment: 8 pages, 7 figure