Kinetic Analysis of the Hydrolysis of Pentose-1-phosphates through Apparent Nucleoside Phosphorolysis Equilibrium Shifts**

Herein, we report an addition to the toolbox for the monitoring and quantification of the hydrolytic decay of pentose-1-phosphates, which are known to be elusive and difficult to quantify. This communication describes how apparent equilibrium shifts of a nucleoside phosphorolysis reaction can be employed to calculate hydrolytic loss of pentose-1-phosphates based on the measurement of post-hydrolysis equilibrium concentrations of a nucleoside and a nucleobase. To demonstrate this approach, we assessed the stability of the relatively stable ribose-1-phosphate at 98 °C and found half-lives of 1.8–11.7 h depending on the medium pH. This approach can be extended to other sugar phosphates and related reaction systems to quantify the stability of UV-inactive and hard-to-detect reaction products and intermediates.     

Die Bestimmung der Alkalien, insbesondere in Pflanzensubstanzen

Ohne Zusammenfassung(Mitteilung aus der agrikulturchemischen Versuchsstation Breslau.)     

Vibronisches Spektralverhalten von Molekülen: XX. Theoretische Untersuchung der S2←S0-Absorption des Pyrens im Rahmen der Herzberg-Teller-Näherung erster Ordnung

Summary On the basis of the completely-optimized S₀ and S₂ molecular geometries of pyrene the vibrational structure of the electronic S₂S₀ transition was calculated within both the Condon approach and the first-order Herzberg-Teller approach. The theoretical results demonstrate the significant influence of vibronic coupling. An analysis of the active vibrational modes is given. The theory-experiment comparison within the Herzberg-Teller approach is satisfactory.

     

Superpositioned dielectrophoresis for enhanced trapping efficiency

One of the major applications for dielectrophoresis is selective trapping and fractionation of particles. If the surrounding medium is of low conductivity, the trapping force is high, but if the conductivity increases, the attraction decreases and may even become negative. However, high-conductivity media are essential when working with biological material such as living cells. In this paper, some basic calculations have been performed, and a model has been developed which employs both positive and negative dielectrophoresis in a channel with interdigitated electrodes. The finite element method was utilized to predict the trajectories of Escherichia coli bacteria in the superpositioned electrical fields. It is shown that a drastic improvement of trapping efficiency can be obtained in this way, when a high conductivity medium is employed.     

Kinetik und Mechanismus der Diazotierung, 18. Mitt.: Kinetik und Mechanismus der Diazotierung des Anilins in chlorwasserstoffsaurem Methanol

Ohne ZusammenfassungI.H. Schmid undG. Muhr, Ber. dtsch. chem. Ges.70, 421 (1937); II.H. Schmid, Z. Elektrochem.43, 626 (1937); III.H. Schmid, Atti X. Congr. internat. Chim. Roma2, 484 (1938); IV.H. Schmid undA. Woppmann, Mh. Chem.83, 346 (1952); V. und VI.H. Schmid undR. Pfeifer, Mh. Chem.84, 829, 842 (1953); VII.H. Schmid, Mh. Chem.85, 424 (1954); zusammenfassender Ber.:H. Schmid, Chemiker-Ztg.78, 565, 683 (1954); VIII.H. Schmid, Mh. Chem.86, 668 (1955); IX.H. Schmid undA. F. Sami, Mh. Chem.86, 904 (1955); X.H. Schmid undE. Hallaba, Mh. Chem.87, 560 (1956); XI.H. Schmid undA. Woppmann, Mh. Chem.88, 411 (1957);H. Schmid, Mh. Chem.88, 161, 344 (1957); XII.H. Schmid undM. G. Fouad, Mh. Chem.88, 631 (1957);H. Schmid, Österr. Pat. 191 399, Kl. 12e₂ (Juni 1957);H. Schmid, Chemiker-Ztg.81, 603 (1957); XIII. und XIV.H. Schmid undCh. Essler, Mh. Chem.88, 1110 (1957);90, 222 (1959); XV.H. Schmid undA. Woppmann, Mh. Chem.90, 903 (1959); XVI.H. Schmid undCh. Essler, Mh. Chem.91, 484 (1960); XVII.H. Schmid undG. Muhr, Mh. Chem.91, 1198 (1960);H. Schmid, Mh. Chem.92, 174 (1961).     

Characterization of a putative sensory [FeFe]-hydrogenase provides new insight into the role of the active site architecture

[FeFe]-hydrogenases are known for their high rates of hydrogen turnover, and are intensively studied in the context of biotechnological applications. Evolution has generated a plethora of different subclasses with widely different characteristics. The M2e subclass is phylogenetically distinct from previously characterized members of this enzyme family and its biological role is unknown. It features significant differences in domain- and active site architecture, and is most closely related to the putative sensory [FeFe]-hydrogenases. Here we report the first comprehensive biochemical and spectroscopical characterization of an M2e enzyme, derived from Thermoanaerobacter mathranii. As compared to other [FeFe]-hydrogenases characterized to-date, this enzyme displays an increased H₂ affinity, higher activation enthalpies for H⁺/H₂ interconversion, and unusual reactivity towards known hydrogenase inhibitors. These properties are related to differences in active site architecture between the M2e [FeFe]-hydrogenase and “prototypical” [FeFe]-hydrogenases. Thus, this study provides new insight into the role of this subclass in hydrogen metabolism and the influence of the active site pocket on the chemistry of the H-cluster.

Characterization of a group D putative sensory [FeFe]-hydrogenase reveals how the active site can be tuned to decrease CO inhibition and increase stability of a reduced H-cluster while retaining the ability to catalyze H⁺/H₂ interconversion.     

Asymmetric Information in a Capital Accumulation Differential Game with Spillover and Learning Effects

Journal of Optimization Theory and Applications - This paper considers a capital accumulation game where the installation costs of investments are lowered by the firm’s own capital stock...     

Vibronic spectral behavior of molecules: XVIII. Theoretical contribution to the S1→S0 fluorescence of the isomeric phenyl naphthalenes within the Herzberg-Teller approach

Theoretical vibronic S₁S₀ line spectra of the isomeric phenyl naphthalenes calculated within the Condon as well as the Herzberg-Teller approaches on the basis of completely optimizedS ₀ andS ₁ molecular geometries, are presented and are contrasted with the experimental fluorescence spectra. The theory-experiment comparison is successful only within the Herzberg-Teller approximation by explicitly including the Dushinsky transformation. An analysis of the significant vibrational modes is given.