(S)‐Selectivity in Phenylacetyl Carbinol Synthesis Using the Wild‐Type Enzyme Acetoin:Dichlorophenolindophenol Oxidoreductase from Bacillus licheniformis

Thiamine diphosphate (ThDP)‐dependent enzymes are well known biocatalysts for the asymmetric synthesis of α‐hydroxy ketones with preferential (R)‐selectivity. Pharmaceutically relevant phenylacetyl carbinol (PAC) has been prepared with absolute (S)‐configuration only on a few occasions using enzyme variants suitably designed through rational site‐directed mutagenesis approaches. Herein, we describe the synthesis of (S)‐phenylacetyl carbinol products with extended reaction scope employing the readily available wild‐type ThDP‐dependent enzyme acetoin:dichlorophenolindophenol oxidoreductase (Ao:DCPIP OR) from Bacillus licheniformis. On a semipreparative scale, cross‐benzoin‐like condensations of methylacetoin (donor) and differently substituted benzaldehydes proceed with almost complete chemoselectivity yielding the target (S)‐1‐hydroxy‐1‐phenylpropan‐2‐one derivatives with high conversion efficiencies (up to 95%) and good enantioselectivities (up to 99%). Ao:DCPIP OR accepts hydroxy‐ and nitrobenzaldehydes and also sterically demanding substrates such as 1‐naphthaldehyde and 4‐(tert‐butyl)benzaldehyde, which are typically poor acceptors in enzymatic transformations. The explorative synthesis of (S)‐phenylpropionyl carbinol mediated by Ao:DCPIP OR via carboligation of benzaldehyde with 3,4‐hexanedione is also reported.

     

Finite element analysis of ion-implanted diamond surface swelling

We present experimental results and numerical finite element analysis to describe surface swelling due to the creation of buried graphite-like inclusions in diamond substrates subjected to MeV ion implantation. Numerical predictions are compared to experimental data for MeV proton and helium implantations, performed with scanning ion microbeams. Swelling values are measured with white-light interferometric profilometry in both cases. Simulations are based on a model which accounts for the through-the-thickness variation of mechanical parameters in the material, as a function of ion type, fluence and energy. Surface deformation profiles and internal stress distributions are analyzed and numerical results are seen to adequately fit experimental data. Results allow us to draw conclusions on structural damage mechanisms in diamond for different MeV ion implantations.     

IBIC analysis of CdTe/CdS solar cells

This paper reports on the investigation of the electronic properties of a thin film CdS/CdTe solar cell with the Ion Beam Induced Charge (IBIC) technique. The device under test is a thin film (total thickness around 10 μm) multilayer heterojunction solar cell, displaying an efficiency of 14% under AM1.5 illumination conditions. The IBIC measurements were carried out using focused 3.150 MeV He ions raster scanned onto the surface of the back electrode. The charge collection efficiency (CCE) maps show inhomogeneous response of the cell to be attributed to the polycrystalline nature of the CdTe bulk material.Finally, the evolution of the IBIC signal versus the ion fluence was studied in order to evaluate the radiation hardness of the CdS/CdTe solar cells in a view of their use in solar modules for space applications.     

Effect of different air-abrasion protocols on topography,surface wettability and adhesion of MDP monomer-based resin cement to zirconia

This study evaluated the effect of air-abrasion protocols on the topography, surface wettability and adhesion of resin cement to zirconia. Ceramic specimens (N?=?49; n?=?7) (15?mm × 2?mm) were randomly allocated to seven groups to be treated with: (1) Air-abrasion with 45?μm Al₂O₃ (A45), (2) 80?μm Al₂O₃ (A80), (3) 30?μm Al₂O₃ coated with SiO₂ (CoJet) (C30), (4) 30?μm Al₂O₃ coated with SiO₂ (Rocatec Soft) (R30), (5) 110?μm Al₂O₃ coated with SiO₂ (Rocatec Plus) (R110); (6) R110R30 (Rocatec) (R110R30) and (7) control, no conditioning (NC). Air-abrasion was performed using a chairside air-abrasion device (2.5?bar, 10?mm, 90?s). Contact angle measurements were performed using goniometry (n?=?5). MDP-based dual resin cement (Panavia F2.0) was bonded on four locations after air-abrasion protocols (n?=?20 per group). Half of the specimens were tested after 24?h and the other half after thermal cycling (×3000, 5–55?°C). Data were analyzed using 1-, 2-way ANOVA and Tukey’s test (alpha = 0.05). Significantly lower contact angle values were observed for groups C30 (62.6?±?0.91), R30 (61.91?±?1.05) and R110R30 (61.54?±?1.02) compared to those of other groups (65.5?±?0.9–110.61?±?0.9) (p?<?0.05). In dry conditions, surface conditioning methods tested did not show significant effect on bond strength (MPa) (10.57?±?1.42–16.86?±?2.54) (p?=?0.238). After thermocycling, bond strength results decreased significantly (p?<?0.05) (12.6–51.2%). R110 (7.18?±?1.34) and A80 (4.92?±?1.53) showed significantly higher bond strength compared to other groups (2.13?±?0.73–4.16?±?1.34) (p?<?0.05). The best wettability and adhesion results with MDP-based resin cement to zirconia was achieved with A80 and R110 air-abrasion.     

A 24-h forecast of solar irradiance using artificial neural network: Application for performance prediction of a grid-connected PV plant at Trieste, Italy

Forecasting of solar irradiance is in general significant for planning the operations of power plants which convert renewable energies into electricity. In particular, the possibility to predict the solar irradiance (up to 24 h or even more) can became - with reference to the Grid Connected Photovoltaic Plants (GCPV) - fundamental in making power dispatching plans and - with reference to stand alone and hybrid systems - also a useful reference for improving the control algorithms of charge controllers. In this paper, a practical method for solar irradiance forecast using artificial neural network (ANN) is presented. The proposed Multilayer Perceptron MLP-model makes it possible to forecast the solar irradiance on a base of 24 h using the present values of the mean daily solar irradiance and air temperature. An experimental database of solar irradiance and air temperature data (from July 1st 2008 to May 23rd 2009 and from November 23rd 2009 to January 24th 2010) has been used. The database has been collected in Trieste (latitude 45°40′N, longitude 13°46′E), Italy. In order to check the generalization capability of the MLP-forecaster, a K-fold cross-validation was carried out. The results indicate that the proposed model performs well, while the correlation coefficient is in the range 98-99% for sunny days and 94-96% for cloudy days. As an application, the comparison between the forecasted one and the energy produced by the GCPV plant installed on the rooftop of the municipality of Trieste shows the goodness of the proposed model.     

HPHT treatment of CO2 containing and CO2-related brown diamonds

Ten type I diamonds containing CO₂ and three diamonds related to these (referred to as “Pseudo CO₂” diamonds) were treated by the HPHT process to observe changes in colour, colour distribution, inclusions, luminescence and spectral features in the visible to the mid-infrared regions. All samples were of predominantly brown colour before the treatment and had rather inhomogeneous colour distribution not related to strain like in classic type Ia brown diamonds. Upon HPHT treatment most of them changed to a more yellow hue, with a greenish modifying colour, but the dominant colour was still brown. The modification of colour was found to be much more discreet than it is the case for deformation-related type Ia brown diamond and the colour was not at all related to known centers such as H3. The colour modifications were caused by the destruction of broad absorption bands in the Vis–NIR spectrum by the HPHT process and generally increased transmission from 400 to 700 nm, likely related to a slight increase in single nitrogen, but no typical HPHT annealing related colour centers such as H3 and H2 were produced in the spectra of the samples. This could be confirmed by the luminescence when excited by shortwave and longwave UV light, under which all samples showed a yellow emission that was practically not modified by the treatment.The infrared spectra of the 10 CO₂ diamonds, defined by the presence of at least the CO₂ stretching (ν₃) and bending (ν₂) absorptions, were unusually modified by the HPHT treatment: the treatment caused the CO₂ bands to increase in intensity in diamonds with low to medium CO₂ content, and the apparently diminished the intensity of the nitrogen-related one phonon absorptions (when present). In the spectra of the three “Pseudo CO₂” samples, which lack by definition the CO₂ peaks, the CO₂ peaks were created and the one phonon absorption reduced by the treatment. The photoluminescence spectra exhibiting several unpublished emission peaks remained practically unchanged by HPHT processing: none of the emissions were annealed out and no new centers created.The data obtained by HPHT treatment leads us to propose, that the theory of solid CO₂ inclusions being responsible for the CO₂ absorptions in diamond may be erroneous, and that the CO₂ may be present structurally. Thus it is proposed that structurally bonded oxygen may play an important role in such diamonds.The present study indicates that treated CO₂ and “Pseudo CO₂” diamonds can in most cases not be identified by the methods available in well-equipped gemmological laboratories, since no detectable defect centers appear to be induced by the treatment.     

Comparison of two nonlinear models for fitting saccadic eye movement data

Saccadic eye movements are rapid shifts in the direction of gaze which are being studied increasingly for clinical and pharmacological purposes. The evaluation of the relationship between amplitude and peak velocity of these ocular movements (the so-called 'main sequence' plot) is particularly useful for characterising the saccade pattern in individual patients. This relationship is nonlinear and the peak velocity tends to achieve an asymptote for high values of amplitude. Since a standard parametrisation of the main sequence based on specific mathematical models has not yet been achieved, in the present study two simple models based on the Michaelis-Menten equation and on an exponential equation are proposed together with their implementation on a microcomputer. Two microcomputer programs are described which estimate the model parameters from the experimental data of the patients using a weighted nonlinear least-squares fit. The two procedures have been tested and compared in a series of 23 healthy volunteers. The following results (mean +/- S.D.) were obtained: Michaelis-Menten model. Km (degrees) = 31.2 +/- 7.7, Vmax (degrees/s) = 841.0 +/- 165.5, root-mean-squared error(%) = 6.0 +/- 1.6; exponential model. K (degrees) = 23.4 +/- 4.6, Vmax (degrees/s) = 578.0 +/- 97.4, root-mean-squared error(%) = 5.4 +/- 1.6. The two techniques of parametrisation provided similar indices of intra-individual variability in 4 healthy volunteers. In conclusion, our methods for saccade parametrisation can be regarded as simple but efficient tools for facilitating research on these ocular movements.     

Effects of the selective tachykinin NK3 receptor agonist NH2-senktide on intraoral intake and taste reactivity responses elicited by NaCl in sodium-replete rats

The purpose of the paper was to find and discuss methods for teaching secure communication. A survey to a sample of nursing schools was executed. The teachers were asked to define 'secure communication' and to relate teaching methods used. Theories supporting the proposed methods were discussed. Conclusively it was found that a joint task force including IMIA WG4 and the IMIA and EFMI nursing groups for selecting an educational strategy in teaching 'secure communication' is highly recommended.     

Intestinal anastomosis with the biofragmentable anastomosis ring

BACKGROUND: The fear of anastomotic complications prevents the spread of the use of the biofragmentable anastomosis ring (BAR) in intestinal surgery. PATIENTS AND METHODS: A total of 453 patients underwent intestinal resection and anastomosis with the BAR. RESULTS: In all, 514 anastomoses have been carried out, 424 (83%) in elective settings, and 90 (18%) in emergency. Fifty-one patients had multiple anastomoses. Reoperation was performed in 4 patients (1%) who had a complete anastomotic leakage. In 13 patients (3%), anastomotic leakage was partial, and only 1 patient required reoperation. No postoperative intestinal obstruction occurred. Four patients (1%) developed late anastomotic strictures, which have been treated by endoscopic dilation. CONCLUSIONS: The results of our experience and those of other large clinical series definitely confirm the effectiveness of the BAR method, which seems to be a standard, easy, rapid, and safe technique either in elective or emergency surgery.     

Nitrogen doping of SiC thin films deposited by RF magnetron sputtering

Silicon carbide thin films (Si _x C _y ) were deposited in a RF (13.56 MHz) magnetron sputtering system using a sintered SiC target (99.5% purity). In situ doping was achieved by introducing nitrogen into the electric discharge during the growth process of the films. The N₂/Ar flow ratio was adjusted by varying the N₂ flow rate and maintaining constant the Ar flow rate. The structure, composition and bonds formed in the nitrogen-doped Si _x C _y thin films were investigated by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Raman spectroscopy and Fourier transform infrared spectrometry (FTIR) techniques. RBS results indicate that the carbon content in the film decreases as the N₂/Ar flow ratio increases. Raman spectra clearly reveal that the deposited nitrogen-doped SiC films are amorphous and exhibited C–C bonds corresponding to D and G bands. After thermal annealing, the films present structural modifications that were identified by XRD, Raman and FTIR analyses.