A novel interferometric wavelength converter

The fiber Kerr effect employment in a wavelength conversion version, owing to low silica nonlinearity, has been prevented by the lack of an efficient interferometric architecture. A novel all-fiber wavelength converter is presented and characterized. The proposed scheme while taking advantage of the Kerr effect properties in standard communication optical fiber overcomes classical interferometric structure limitations, such as high environmental sensitivity and difficult operating management. A comparison with these architectures is discussed. Operation up to 3 Gb/s is demonstrated in the whole third communication window     

Dynamics of cyanide binding to ferrous Scapharca inaequivalvis homodimeric hemoglobin

Flash photolysis experiments have been carried out for the first time on a hemoglobin ferrous cyanide adduct with an 8 ns laser pulse. A 95% nonexponential rebinding process occurs within 2 micros after full photolysis in ferrous cyanide dimeric Scapharca inaequivalvis hemoglobin (HbI), indicating that once photolyzed the cyanide anion is not able to escape from the protein matrix and rebinds to the heme iron. The resonance Raman spectrum of the 10 ns photoproduct is identical to that of the fully relaxed deoxy derivative, indicating that in the ferrous cyanide HbI adduct protein relaxation occurs within 10 ns after photolysis. This behavior is at variance with that of the carbonmonoxy HbI derivative in which very little geminate rebinding is observed and the photoproduct relaxes with a lifetime of 1 micros. The fast relaxation of the cyanide HbI photoproduct can be accounted for by the small perturbation of the heme structure induced by cyanide binding to ferrous HbI. This is consistent with a deoxy-like conformation of the HbI ferrous cyanide adduct and implies that the pathway for relaxation involves only minor local rearrangements of the heme moiety. Photolysis experiments carried out on ferrous cyanide horse myoglobin, which can be saturated only partially, show a qualitatively similar behavior in ligand rebinding, indicating that the geminate process of the cyanide anion is a general phenomenon in hemoproteins.     

Eighteen years of home care: from assistance by phone to a complete service within the health care system

A postal questionnaire was undertaken to assess the current facilities available for adolescents in Irish hospitals. A previous survey showned that no facilities existed whereas this survey demonstrates some improvements but adolescents are still admitted to adult wards, have inappropriate waiting facilities at outpatients and a limited number of joint Paediatric-Adult clinics. The ability of paediatricians to assess risk taking behaviour and the provision of age appropriate information at ward and outpatient level was assessed. The results demonstrate there is need for improvement in all aspects of adolescent care in Irish hospital services. This needs to be addressed promptly as 66% of the paediatricians surveyed were considering the development adolescent services in their hospitals.     

Spectral analysis of the rotational component of seismic ground motion

An algorithm for the spectrum of the rotational component of surface ground motion during earthquake is derived. To obtain the rotation the total motion is decomposed into the wave components. Then the rotational motion is obtained in terms of the horizontal and vertical components treated as non-stationary random processes. The evolutionary spectrum of the rotational acceleration is a function of respective translational spectra, their co-spectrum and respective wave parameters. The analysis shows a shift of the higher frequency components in the rotational spectrum. The rotation is a function of the time derivative of translational components.     

Evaluation of the electrical conductivity via the time-dependent integral boltzmann equation

Following the integral method developed in neutron transport theory, the exact time-dependent density distribution and current density describing electron motion under the influence of a conservative force are obtained. From the expression for the current density, the validity of Ohm's law for various scattering interaction models can be verified.     

20-Gb/s PolDM Duobinary Transmission Over 350-km SSMF Supported by a Polarization Stabilizer and an Optical Dispersion Compensator

A 20-Gb/s transmission over 350-km standard single-mode fiber exploiting duobinary dispersion robustness and polarization-division multiplexing has been demonstrated. The system performance is evaluated employing an automatic endless polarization stabilizer and a suitably designed transmitter-side optical dispersion compensator.     

The apolar distal histidine mutant (His69-->Val) of the homodimeric Scapharca hemoglobin is in an R-like conformation

The effect of the apolar mutation of the distal histidine (His69-->Val) has been studied in the cooperative homodimeric hemoglobin from the mollusc Scapharca inaequivalvis. Absorption, circular dichroism, and resonance Raman spectroscopy point to a more symmetric heme structure of the deoxy derivative, which is indicative of an R-like conformation of the deoxy heme. Resonance Raman spectroscopy also brings out alterations in the geometry and interactions of the bound CO molecule. The iron-carbon stretching frequency is decreased by about 30 cm-1 with respect to the native protein, while the diatomic ligand stretching frequency is increased by about the same degree. Consistent with the structural changes, the ligand binding properties are significantly altered. In the mutant the overall rate and the affinity for CO binding are increased about 100-fold with respect to the native protein, and cooperativity is abolished. In addition, the amplitude and the rate of the geminate rebinding process increase significantly. This finding may be correlated to the longer average residence time of the photolyzed CO molecule within the heme pocket of the H69V mutant, as indicated by molecular dynamics simulations.     

Immobilization of Lathyrus cicera Amine Oxidase on Magnetic Microparticles for Biocatalytic Applications

Amine oxidases are enzymes belonging to the class of oxidoreductases that are widespread, from bacteria to humans. The amine oxidase from Lathyrus cicera has recently appeared in the landscape of biocatalysis, showing good potential in the green synthesis of aldehydes. This enzyme catalyzes the oxidative deamination of a wide range of primary amines into the corresponding aldehydes but its use as a biocatalyst is challenging due to the possible inactivation that might occur at high product concentrations. Here, we show that the enzyme’s performance can be greatly improved by immobilization on solid supports. The best results are achieved using amino-functionalized magnetic microparticles: the immobilized enzyme retains its activity, greatly improves its thermostability (4 h at 75 °C), and can be recycled up to 8 times with a set of aromatic ethylamines. After the last reaction cycle, the overall conversion is about 90% for all tested substrates, with an aldehyde production ranging between 100 and 270 mg depending on the substrate used. As a proof concept, one of the aldehydes thus produced was successfully used for the biomimetic synthesis of a non-natural benzylisoquinoline alkaloid.