Control of dangerous substances in discharges and microbiological abatement: European framework and a case study of an ozone disinfection system.

Directive 2000/60/EC requires the achievement of a 'good chemical status' for surface water within pre-established dates. Disinfection is needed to achieve compulsory final microbial limit values (in Italy for wastewater discharges the parameter Escherichia coli - EC - is imposed by law with a maximum limit value of 5,000 cfu/100 mL). Liquid waste and disinfection by-products must be considered when designing appropriate monitoring of dangerous substances; the specific classes of substances must be investigated according to the typology of received wastewaters and liquid wastes (where applicable) and specific analytical techniques, with Limit of Detection (LOD) lower than the limit values, must be applied; the difficulties faced by national and regional environmental control Agencies is that these techniques have to be applied during ordinary activity and not only for research purposes. The study aims to present the control of dangerous substances, as a screening view, in wastewater treatment plant (WWTP) discharges in the province of Venice (Northern Italy) for the period 2007-2010 based on available data from institutional controls. In addition, the wastewater disinfection process with ozone applied to a medium size WWTP (45,000 Population Equivalents) is presented as a case study, with a view to assessing the microbiological abatement efficacy and the presence of dangerous substances. Discharge quality of the WWTPs in the province of Venice presented mean values that were higher than the LOD, but only for certain metals. For the Paese plant, zinc and chloroform were the only micro-pollutants detected with a higher level than the LOD. From microbiological data in the period 2006-2011 the disinfection abatement efficiency for Paese was, in most cases above 99% for EC, faecal coliform (FC), faecal streptococci (FS) while efficiency was slightly lower for total coliform (TC); however, the proposed criterion aimed at respecting 99.99% abatement was not completely satisfied. Therefore, despite the high organic and industrial load of the considered plant and the need to find an alternative system for chlorine, as chlorine disinfection has been banned in the Veneto region since December 2012, ozone efficiency is not completely satisfactory and other systems such as peracetic or performic acids and UV systems must be considered.

Multilayer architectures based on a-SiC:H material: tunable wavelength filters in optical processing devices.

The characteristics of tunable wavelength filters based on a-SiC:H multilayered stacked pin cells are studied both theoretically and experimentally. The optical transducers were produced by PECVD and tested for a proper fine tuning of the cyan and yellow fluorescent proteins emission. The active device consists of a p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructures sandwiched between two transparent contacts. Experimental data on spectral response analysis, current-voltage characteristics and color and transmission rate discrimination are reported. Cyan and yellow fluorescent input channels were transmitted together, each one with a specific transmission rate and different intensities. The multiplexed optical signal was analyzed by reading out, under positive and negative applied voltages, the generated photocurrents. Results show that the optimized optical transducer has the capability of combining the transient fluorescent signals onto a single output signal without losing any specificity (color and intensity). It acts as a voltage controlled optical filter: when the applied voltages are chosen appropriately the transducer can select separately the cyan and yellow channel emissions (wavelength and frequency) and also to quantify their relative intensities. A theoretical analysis supported by a numerical simulation is presented.

Semiconductor device as optical demultiplexer for short range optical communications.

In this paper we present results on the use of a multilayered a-SiC:H heterostructure as a wavelength-division demultiplexing device for the visible light spectrum. The proposed device is composed of two stacked p-i-n photodiodes with intrinsic absorber regions adjusted to short and long wavelength absorption and carrier collection. An optoelectronic characterisation of the device was performed in the visible spectrum. Demonstration of the device functionality for WDM applications was done with three different input channels covering the long, the medium and the short wavelengths in the visible range. The recovery of the input channels is explained using the photo-current spectral dependence on the applied voltage. An electrical model of the WDM device is proposed and supported by the solution of the respective circuit equations. Short range optical communications constitute the major application field, however other applications are also foreseen.

Detection of change in fluorescence between reactive cyan and the yellow fluorophores using a-SiC:H multilayer transducers.

Optical colour sensors based on multilayered a-SiC:H heterostructures can act as voltage controlled optical filters in the visible range. In this article we investigate the application of these structures for Fluorescence Resonance Energy Transfer (FRET) detection, The characteristics of a-SiC:H multilayered structure are studied both theoretically and experimentally in several wavelengths corresponding to different fluorophores. The tunable optical p-i'(a-SiC:H)-n/p-i(a-Si:H)-n heterostructures were produced by PECVD and tested for a proper fine tuning in the violet, cyan and yellow wavelengths. The devices were characterized through transmittance and spectral response measurements, under different electrical bias and frequencies. Violet, cyan and yellow signals were applied in simultaneous and results have shown that they can be recovered under suitable applied bias. A theoretical analysis supported by numerical simulation is presented.

Pinpi'n and pinpii'n multilayer devices with voltage controlled optical readout.

In this paper we present results on the optimization of a pinpii'n type a-Si:H based three color detector with voltage controlled spectral sensitivity. The sensor element consists on a glass/ITO/p-i-n a-SiC:H multilayer structure which faces the incident illumination, followed by a-SiC:H(-p)/a-SiC:H(-i)/Si:H(-i')/SiC:H(-n)/ITO heterostructure, that allows the optically addressed readout. Results show that this approach leads to regionally different collection parameters resulting in multispectral photodiodes, coding for red (R), blue (B), and two green (G) components. In the polychromatic operation mode different sensitivity ranges are selected by switching between different biases so that the basic colors can be resolved with a single device. Positive bias is needed under blue irradiation and moderate reverse bias under green. The threshold voltage between green and red sensitivity depends on the thickness of the bottom a-SiC:H (-i) layer, and corresponds to the complete confinement of the absorbed green photons across the pinpi sequence. As the thickness of the a-Si:H i'-layer increases, the self-reverse effect due to the front absorption will be balanced by the decrease of the self-forward effect due to the back absorption shifting the threshold voltage to lower reverse bias. The various design parameters are discussed and supported by a numerical simulation.

Modeling a-SiC:H tandem pinpin and pinip photodiodes for color sensor application.

The present paper reports the optical properties of multilayer structures composed by p-i-n cells based on a-SiC:H or a-Si:H material. Different structures are studied in order to obtain image sensors that accomplish color filtering in addition to image pattern recognition. A simple theoretical model is developed to explain sensors behavior and to derive the optical-readout experimental procedure. Electrical models for the sensors are established for simulation purposes and to compare photocurrent signals with experimental data. A numerical simulation of the JV characteristic and of the spectral response is also presented in order to show possible future optimization of the device. Two main structures are studied, namely p-i-n/p-i-n and p-i-n/n-i-p tandem cells.

Photocurrent and spectral response analysis of a-SiC:H pinip and pinpin photodiodes.

We present in this paper results about the analysis of photocurrent and spectral response in a-SiC:H/a-Si:H pinpin and pinip structures. Our experiments and analysis reveal the photocurrent profile to have a strong nonlinear dependence on the externally applied bias and on the light absorption profile, i.e., on the incident light wavelength and intensity. Our interpretation points out the cause of such effect to a self biasing of the junctions under certain unbalanced light generation of carriers and to an asymmetric reaction of the internal electric fields to the externally imposed bias. The possibility to relate such a behavior to the light intensity and wavelength indicates realistic hypothesis of using these structures and this effect for color recognition sensors. We present results about the experimental characterization of the structures and numerical simulations obtained with the program ASCA. Considerations about electrical field profiles and inversion layers will be taken into account to explain the optical and voltage bias dependence of the spectral response. Our results show that in both structures the application of an external electrical bias (forward or reverse) mainly influences the field distribution within the less photo excited sub-cell.

Observation of the naive-T-odd Sivers effect in deep-inelastic scattering.

Azimuthal single-spin asymmetries of leptoproduced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from nonvanishing Sivers effects for pi(+), pi(0), and K(+/-), as well as in the difference of the pi(+) and pi(-) cross sections.

Double-hadron leptoproduction in the nuclear medium.

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Measurement of the tensor structure function b1 of the deuteron.

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target.

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.

Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering.

Double-spin asymmetries of semiinclusive cross sections for the production of identified pions and kaons have been measured in deep inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with reanalyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.

Evidence for quark-hadron duality in the proton spin asymmetry A1.

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2 above 1.6 GeV2.

Q2 dependence of nuclear transparency for exclusive rho0 production.

Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.

[Tracheostomy in pediatrics patients]. / Tracheostomia in et pediatrica.

This is a case study of 79 children who under-went a tracheostomy with three different techniques, used in succession on three different groups of patients: surgical, percutaneous with progressive probes and translaryngeal technique. The pediatric patient, only under the age of 10, starts showing clear-cut anatomical differences compared to an adult, which gradually become more marked the younger the patient is. The causes of increased difficulties that can normally be found in these patients are obviously due to the reduced diameter of the airway and, above all, the high degree of pliability of the cartilaginous frame. After the discovery that even minimal external pressure can cause the collapse of the tracheal walls, it was decided to adopt the systematic use of a rigid bronchoscope, in order to be able to offer internal support to the anterior wall. The following advantages were obtained in the various techniques: In surgery it permitted the reduction, through the protrusion of the trachea, of the size of the operatory field, of the tracheal opening and consequently of the local trauma. It also caused less bleeding and reduced the risk of lesion to the pleural dome which are very frequent when a bronchoscope is not used. In the percutaneous method the bronchoscope allowed the application of the technique without complications, even in infants of only a few months' old, because it eliminated tracheal squashing, caused by the introduction of the needle, dilators and especially cannula, and the relative danger of lesion to the posterior wall of the trachea. This complication which was always impending in the original technique, which does not involve the use of a rigid bronchoscope, is the main reason which lead to the ban on PDT for patients younger than 16-18. In the translaryngeal method the advantages are of minor importance because they are limited to the initial stage of the procedure, the introduction of the needle and guide wire which are quicker and more precise. As regard the dilation, the TLT mode has a high level of intrinsic safety and is perfectly suitable to the anatomy of the child. In fact it is carried out from the inside towards the outside, causing a tendency to evertion of the tracheal wall which the physician must even limit with external pressure. It is remarkable that this contrast in pressure and the resulting compression of the peristomal tissues creates advantages, which are essential in younger children, that cannot be found in other tracheal techniques. These advantages are the complete absence of loss of blood, minimal local trauma and a perfect adherence of the stoma to the cannula, particularly effective at level of the tracheal wall.

Infrared and Raman spectra and theoretical study of methyl trifluoromethyl sulfone, CF3SO2CH3.

The infrared and Raman spectra were obtained for liquid CF3SO2CH3, as well as the infrared spectrum of the gaseous substance. The molecular geometry was optimized by means of the Hartree-Fock (HF), second order electron correlation (MP2) and density functional theory (DFT) procedures of quantum chemistry, resulting in a structure with Cs symmetry. The wavenumbers corresponding to the normal modes of vibration were calculated using the DFT (B3LYP/6-31G**) approximation and their agreement with the measured values improved after scaling of the associated force field. An assignment of bands is proposed on the basis of such calculations and the comparison with related molecules.

Molecular dynamics simulation of double proton transfer: adenine-thymine base pair.

Molecular dynamics of proton transfer was simulated from normal (N) to tautomeric (T) form of the base pair (bp) adenine-thymine (A-T). The results for the model system, consisting of one A-T base pair in SPC/E water, was analysed in terms of its hydration properties, difference on free energy, conformational changes, and magnetic properties. It is suggested that during proton transfer the base pair remains on the same conformational state. The free energy of the protons transfer appears to be almost insensitive to the presence of water. The overall hydrophobicity of the A-T pairs is slightly modified by the proton transfer the N form being a little more hydrophobic. The behavior of the magnetic shielding suggests that a current is produced in the ring of the hydrogen bonds due to strong pi -electron delocalization in the amide-amidine complex.

The second exon-encoded factor XII region is involved in the interaction of factor XII with factor XI and does not contribute to the binding site for negatively charged surfaces.

Contact system activation, in vitro, is triggered by activation of factor XII (FXII) on binding to an activator, such as negatively charged surfaces. A putative surface-binding site of FXII has been located within the amino acid residues 1-28 by identifying the epitope recognized by a monoclonal antibody (MoAb), B7C9, which inhibits kaolin-induced clotting activity. To further elucidate the role of the amino terminal binding site in the regulation of FXII activation, we have characterized a FXII recombinant protein (rFXII-triangle up19) deleted of the amino acid residues 3-19, which are encoded by the second exon of FXII gene. A plasmid encoding for rFXII-triangle up19 was constructed and expressed in HepG2 cells by using vaccinia virus. Purified rFXII-triangle up19 migrated as a single band of Mr 77,000 on sodium dodecyl sulfate (SDS)-polyacrylamide gel, did not bind to MoAb B7C9 immobilized on Protein A-Sepharose, thus confirming that it lacked the epitope for this MoAb, and had no amidolytic activity towards the chromogenic substrate S-2302 in the absence of activator. rFXII-triangle up19 specific clotting activity was lower (44%) than that of native FXII. The activation rate of rFXII-triangle up19 by kallikrein in the absence of dextran sulfate was about four times higher than that of full-length FXII and was increased in the presence of dextran sulfate. However, rFXII-triangle up19 underwent autoactivation in the presence of dextran sulfate. Labeled rFXII-triangle up19 bound to kaolin, which binding was equally well inhibited by either, rFXII-triangle up19 or full-length FXII (IC50 = 7.2 +/- 2.2 nmol/L for both proteins). Accordingly, a synthetic peptide corresponding to FXII amino acid residues 3-19 did not inhibit the binding of labeled full-length FXII to kaolin. rFXII-triangle up19 generated a similar amount of FXIIa- and kallikrein-C1-inhibitor complexes in FXII-deficient plasma in the presence of kaolin, as did full-length FXII; but generated less factor XIa-C1-inhibitor complexes (50%) than full-length FXII. This impaired factor XI activation by rFXII-triangle up19a was also observed in a purified system and was independent of the presence of high molecular weight kininogen. Furthermore, the synthetic peptide 3-19, preincubated with factor XI, inhibited up to 30% activation of factor XI both in the purified system as well as in plasma. These results together indicate that amino acid residues 3-19 of FXII are involved in the activation of factor XI and do not contribute to the binding of FXII to negatively charged surfaces.

Hematopoietic support and cytokine expression of murine-stable hepatocyte cell lines (MMH).

It was recently reported that transgenic expression in the liver of truncated human Met renders hepatocytes constitutively resistant to apoptosis and reproducibly permits their immortalization. The derived stable cell lines (MMH from Met murine hepatocyte) are highly differentiated and nontransformed. In this report, the capacity of MMHs to support in vitro hematopoiesis is characterized. By reverse-transcription polymerase chain reaction, the expression by MMHs of cytokines involved in the survival and self-renewal of early progenitor cells (stem cell factor and FLT3 ligand) as well as those acting at different stages of progenitor differentiation (interleukin [IL] 1beta, IL-3, leukemia inhibitory factor, IL-6, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, macrophage colony-stimulating factor, and thrombopoietin) was shown. A ribonuclease protection assay further substantiated the presence of at least six cytokine transcripts in MMH lines. Cocultures between MMH layers and progenitor-enriched fetal liver hematopoietic cells resulted in a 40-fold to 80-fold expansion of total hematopoietic cells and in a 2.5-fold expansion of clonogenic progenitors after 1 to 2 weeks. Hematopoiesis was maintained for up to 6 weeks with formation of typical cobblestone cell areas and continuous differentiation of precursor into cells at various degrees of maturation. At 5 weeks of coculture, clonogenic progenitors were maintained at 20% of the input level in coculture with embryonic-derived hepatocytes, showing the ability of hepatocyte feeder layer to support survival and possibly self-renewal of clonogenic progenitors. Therefore, the data emphasize a direct role of the hepatocyte in sustaining hematopoietic cell proliferation and differentiation.