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Abstract: A small fraction of the total cellular amount of nuclear transcription factor p53 seems to be located at and within mitochondria. Transcription factors of the steroid receptor superfamily that, like p53, lack a classical mitochondrial leader sequence are nonetheless imported into mitochondria where they regulate mtDNA transcription through binding to specific recognition sequences. Here, we examined seven candidate sequences from the human mitochondrial genome with similarity to the consensus p53 binding motif. Two imperfect half-sites at coordinate 1553 with homology to the nuclear IGF-BP3 box A binding sequence are demonstrated to confer responsivity to p53 and the p53 relatives p73α and β in the context of the cell nucleus. Mitochondrial p53 may thus bind directly to mtDNA and, perhaps, be involved in the regulation of mitochondrial transcription/replication. [Copyright &y& Elsevier]

Discusses the use of blood group antigens of the ABO system to illustrate O-linked glycoprotein synthesis. Result of a series of exergonic non-template glycosyltransferase reactions; Presence of intermediate A[sub 1] and A[sub 2] blood group constellation in erythrocytes of a patient with a type I carbohydrate deficient glycoprotein syndrome; Effect of GDP-fucose deficiency on membrane bound and soluble glycoconjugates.

The water distribution of a Nafion-based membrane in a direct methanol fuel cell was analyzed in-operando using high resolved synchrotron X-ray radiography. A specially developed fuel cell design that meets the requirements for radiography as well as for stable cell operation was used. Different electric loads were applied during cell operation. A correlation between the electric load of the cell and the thickness of the membrane was found: the membrane thickness increased with increasing current density. The impact of local water drop dynamics on the water distribution in the membrane and the electrodes have been analyzed. We found a strong influence of water drops in the cathode channel on the water distribution in the adjacent area of the Nafion membrane. [ABSTRACT FROM AUTHOR]

Abstract: We present a traveling-wave-type optical parametric amplifier (OPA) pumped at 1.03μm by a Yb:KGW laser that produces tunable high-energy pulses of 6.5–4μJ in the mid-infrared (mid-IR) region from 3.6 to 7μm. Pumping with negatively chirped pulses generates nearly transform-limited (TL) mid-IR pulses of 300–330fs length. Pumping with TL pulses of 200fs not only decreases the output energy by a factor of 1.5, but also decreases the mid-IR pulse-length to 160fs after additional compression. The compact and simple OPA setup is ideal for femtosecond infrared experiments in the fingerprint region. [Copyright &y& Elsevier]

The alcoholysis reaction of phenylisocyanate with cyclohexanol ( I ) and of 2,4-toluene-diisocyanate with chloraldhydrate ( II ) is studied by infrared absorption spectroscopy in combination with anharmonic frequency calculations using density functional theory. It is shown that the progress of the reaction can be monitored by measuring infrared marker bands in the isocyanate NCO and alcohol OH stretching regions. Analysis of spectra obtained as a function of time for different temperatures yields a second-order kinetics with an Arrhenius activation energy of 6.7 ± 0.2 and 2.8 ± 0.3 kcal/mol for reaction I and II , respectively. [ABSTRACT FROM AUTHOR]

We report on combined simultaneous temporal and spatial laser pulse shaping by utilizing light polarization properties. Thereto, a setup comprising a temporal pulse shaper, a waveplate, and a spatial shaper was developed and characterized by comparison with simulations. This enables to simultaneously shape one polarization component temporally and spatially while the perpendicular polarization component is modified temporally. The spatially and temporally modulated light fields were recorded and visualized by suitable contour plots, which was particularly demonstrated for cylindrically symmetric pulse profiles. Moreover, temporally and spatially shaped pulses were applied for two-photon excited fluorescence of dyes. These measurements were conducted by scanning third order phase functions for specific spatial pulse components which yields an enhanced contrast difference between fluorescing dyes. The presented temporal and spatial shaping method of ultrashort laser pulses has a high potential for biophotonic applications. [ABSTRACT FROM AUTHOR]