Single-pulse stimulated Raman scattering spectroscopy

We demonstrate the acquisition of stimulated Raman scattering spectra with the use of a single femtosecond pulse. High-resolution vibrational spectra are obtained by shifting the phase of a narrow band of frequencies within the input pulse spectrum, using spectral shaping. The vibrational lines are resolved via amplitude features formed in the spectrum after interaction with the sample. Using this technique, low-frequency Raman lines (<100 cm?1) are observed on both the Stokes and anti-Stokes sides.     

Observation ofD S ** (2536) meson production by neutrinos in BEBC

Zeitschrift für Physik C Particles and Fields - Neutrino interactions in BEBC produce theD ** (2536) charmed strange meson. The mass of this state is 2534.2±1.2 MeV. The production rate...     

Determination of the ratior v =d v u v of the valence quark distributions in the proton from neutrino and antineutrino reactions on hydrogen and deuterium

Zeitschrift für Physik C Particles and Fields - A set of proton longitudinal polarized distributions, worked out under the assumption of small gluon polarization, is used to evaluate several...     

An Improved Method for the Mono-Hydroxymethylation of Pyridines. A Modification of the Minisci Procedure

The reaction of N-methoxy-derivatives of pyridines in methanol with ammonium persulphate gives improved yields of mono-hydroxymethylated products. In contrast to the original Minisci procedure the reaction requires only catalytic amounts of ammonium persulphate. Evidence is presented which establishes that the reaction does not proceed via an intramolecular pathway.     

Biomolecular Release Stimulated by Electrochemical Signals at a Very Small Potential Applied

DNA release electrochemically stimulated by applying ?10 mV on the modified electrode was studied. The release process was based on the local (interfacial) pH change produced upon H₂O₂ reduction electrocatalyzed by the immobilized microperoxidase‐11. SiO₂ nanoparticles attached to the electrode surface and functionalized with trigonelline and boronic acid species changed their electrical charge from positive to negative upon the interfacial pH change, thus allowing electrostatic adsorption of negatively charged DNA on the positive interface and then its repulsion/release from the negative interface. The loaded/released DNA molecules were labeled with a fluorescent dye to allow easy detection of the released DNA molecules. The important feature of the developed system is the controlled DNA release upon applying very small electrical potential on the modified electrode.     

Einfluß von Form und Polarität der Moleküle auf das Röntgenspektrum von Flüssigkeiten

Zeitschrift für Physik A Hadrons and nuclei - Im Röntgenspektrogramm der meisten Flüssigkeiten tritt nur ein einziger intensiver „amorpher Ring“ auf. Dessen Zusammenhang...     

Cofibrations of algebras

Summary The chain complex of a twisted free product A_*t, FK, is chain homotopy equivalent to a differential graded algebra, which is identified to be a confibration of algebras as defined by Quillen. Under certain connectivity conditions we obtain a long exact sequence connecting the homologies of A, K, and A_*t FK. In particular we derive a long exact sequence connecting the homologies of Y, X and (Y U_g CX) (, C, are the loop, the cone and the suspension constructions respectively). A chain complex equivalent to the chain complex of the Milnor free group FX is recognized, from which results a theorem of Bott and Samelson that H(X) is freely generated as a graded algebra by H(X).     

An Enzyme‐Based Half‐Adder and Half‐Subtractor with a Modular Design

A half‐adder and a half‐subtractor have been realized using enzymatic reaction cascades performed in a flow cell device. The individual cells were modified with different enzymes and assembled in complex networks to perform logic operations and arithmetic functions. The modular design of the logic devices allowed for easy re‐configuration, enabling them to perform various functions. The final output signals, represented by redox species [Fe(CN)₆]^3?/4? or NADH/NAD⁺, were analyzed optically to derive the calculation results. These output signals might be applicable in the future for actuation processes, for example, substance release activated by logically processed signals.     

Biofuel cell controlled by enzyme logic network — Approaching physiologically regulated devices

A “smart” biofuel cell switchable ON and OFF upon application of several chemical signals processed by an enzyme logic network was designed. The biocomputing system performing logic operations on the input signals was composed of four enzymes: alcohol dehydrogenase (ADH), amyloglucosidase (AGS), invertase (INV) and glucose dehydrogenase (GDH). These enzymes were activated by different combinations of chemical input signals: NADH, acetaldehyde, maltose and sucrose. The sequence of biochemical reactions catalyzed by the enzymes models a logic network composed of concatenated AND/OR gates. Upon application of specific “successful” patterns of the chemical input signals, the cascade of biochemical reactions resulted in the formation of gluconic acid, thus producing acidic pH in the solution. This resulted in the activation of a pH-sensitive redox-polymer-modified cathode in the biofuel cell, thus, switching ON the entire cell and dramatically increasing its power output. Application of another chemical signal (urea in the presence of urease) resulted in the return to the initial neutral pH value, when the O₂-reducing cathode and the entire cell are in the mute state. The reversible activation–inactivation of the biofuel cell was controlled by the enzymatic reactions logically processing a number of chemical input signals applied in different combinations. The studied biofuel cell exemplifies a new kind of bioelectronic device where the bioelectronic function is controlled by a biocomputing system. Such devices will provide a new dimension in bioelectronics and biocomputing benefiting from the integration of both concepts.     

Implanted biofuel cell operating in a living snail

Implantable biofuel cells have been suggested as sustainable micropower sources operating in living organisms, but such bioelectronic systems are still exotic and very challenging to design. Very few examples of abiotic and enzyme-based biofuel cells operating in animals in vivo have been reported. Implantation of biocatalytic electrodes and extraction of electrical power from small living creatures is even more difficult and has not been achieved to date. Here we report on the first implanted biofuel cell continuously operating in a snail and producing electrical power over a long period of time using physiologically produced glucose as a fuel. The "electrified" snail, being a biotechnological living "device", was able to regenerate glucose consumed by biocatalytic electrodes, upon appropriate feeding and relaxing, and then produce a new "portion" of electrical energy. The snail with the implanted biofuel cell will be able to operate in a natural environment, producing sustainable electrical micropower for activating various bioelectronic devices.