Search

In the last decades Silicon Carbide (SiC) received special attentions, in particular as semiconductor material, because is considered as alternative to Silicon for the future high-power, low consumption, radiation-hard microelectronics devices. This ambitious goal is particularly interesting also for the physics of the detectors. In this work are discussed some of the recent results obtained by SiCILIA collaboration, a joint research activity between INFN and IMM institutions to increase the level of technological development in the field of SiC detectors.

Proximal focal femoral deficiency (PFFD) is a rare musculoskeletal malformation that occurs in 0.11-0.2 per 10,000 live births. This congenital anomaly involves the pelvis and proximal femur with widely variable manifestations, from mild femoral shortening and hypoplasia to the absence of any functional femur and acetabular aplasia. Prenatal diagnosis of PFFD is still a challenge, but early recognition of this malformation could provide useful information to both parents and physicians concerning management and therapeutic planning. For this review, we analyzed all the cases of prenatally diagnosed PFFD that were reported in the literature from 1990 to 2014 and provide a description of the most common prenatal sonographic findings.

Multiple alpha coincidence and correlations are studied in the reaction $^{12}$C+$^{12}$C at 95 MeV for fusion-evaporation events completely detected in charge. Two specific channels with Carbon and Oxygen residues in coincidence with $\alpha$-particles are addressed, which are associated with anomalously high branching ratios with respect the predictions by Hauser-Feshbach calculations. Triple alpha emission appears kinematically compatible with a sequential emission from a highly excited Mg. The phase space distribution of $\alpha$-$\alpha$ coincidences suggests a correlated emission from a Mg compound, leaving an Oxygen residue excited above the threshold for neutron decay. These observations indicate a preferential $\alpha$ emission of $^{24}$Mg at excitation energies well above the threshold for $6-\alpha$ decay., Comment: 21 pages, 17 figures, second paper of a series of two

A new measurement of the dynamical dipole emission was performed in the system O-16 + Sn-116 at 12 MeV/nucleon. These data, together with those measured at 8.1 MeV/nucleon and 15.6 MeV/nucleon on the same system, provide the dependence of the dynamical dipole total emission yield on the beam energy. The energy removed by preequilibrium charged particles emission was directly measured and this made possible the direct estimation of the compound nucleus excitation energy. The experimental results show a weak increase of the dynamical dipole total yield with beam energy and they are in agreement both in trend and in absolute values with the predictions of the theoretical model based on the Boltzmann-Nordheim-Vlasov approach. The measured gamma-ray angular distribution has a dipole character but with a strong quenching probably owing to the rotation of the dipolar axis during the fusion and thermalization processes.

The $^{12}$C+$^{12}$C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows to select a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited $^{24}$Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density of light nuclei above the threshold for particle emission. In particular, a fast increase of the level density parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or $\alpha$-clustering effects. These channels are studied in further details in the second paper of the series., Comment: 24 pages, 15 figures, first paper of a series of two

Transgenic grapefruit plants (Citrus paradisi cv. ‘Duncan’) with the isopentenyltransferase (ipt) gene under the control of APETALA3 promoter have been produced using Agrobacterium-mediated transformation. The relative expression level of the ipt gene was between 2.3 and 7 times higher in transformed plants than in the wild-type but despite the presence of a tissue-specific promoter, the expression was not limited only to flower tissue. Increased levels of trans-zeatin riboside between 9.4 and 32-fold found in transgenic grapefruit were considered the consequence of ectopic expression of the ipt gene. Chlorophyll levels in fully expanded uppermost leaves were also about 30% higher in transgenic than in wild-type plants. Involvement of cytokinins in control of expression of three pathogenesis-related protein genes: β-1,3-glucanase, a stress related PR gene 24P220, and an acidic chitinase, 24P262 was examined. Expression of β-1,3-glucanase, and 24P220 gene were significantly enhanced in transgenic plants while the expression of chitinase was reduced to low levels. Our results confirm the effect of cytokinins on expression of genes implicated in the response of grapefruit plants to pathogen attack and suggest a possible role of cytokinins in pathogen resistance.

Transgenic plants of grapefruit (Citrus paradisi Macf.) cvs. ‘Duncan’, ‘Flame’, ‘Marsh’, and ‘Ruby Red’ were obtained using Agrobacterium tumefaciens-mediated transformation of seedling epicotyl tissue. Two citrus tristeza virus (CTV)-derived candidate resistance genes: ‘392’ (3′ region of the p23 ORF plus 3′ untranslated region—UTR) and ‘p23 hairpin’ (sense-p23 ORF plus UTR plus antisense-p23 ORF) were introduced into grapefruit using Agrobacterium strains EHA105 and EHA101, respectively. Epicotyl explants from 1-mo.-old in vitro etiolated seedlings were incubated in bacterial suspension. Green shoots that formed on explants after 4–5 wk after bacterial incubation were tested for the presence of the GUS gene by histochemical analysis. The percentage of GUS-positive shoots and transformation efficiency was 30.3 ± 3.3% and 3.5% for treatment with EHA101 and 15.3 ± 1.7% and 1.3% for treatment with EHA105. GUS-positive shoots were micrografted onto Carrizo citrange (Citrus sinensis L. Osbeck × Poncirus trifoliata L. Raf.) seedling rootstocks, and the presence of transgene sequences in these plants was confirmed by polymerase chain reaction (PCR), Southern blot, and reverse transcription PCR analyses. Resulting transgenic grapefruit plants were challenged with CTV and tobacco mosaic virus using a protoplast challenge assay as an initial screen to determine the effects of the transgenes on virus replication. Although complete RNA-mediated resistance was not achieved, preliminary results showed that 5.2% of the recovered transgenic plants containing the ‘392’ CTV-derived sequence repeatedly exhibited reduced CTV replication in protoplasts. These plants are being further evaluated using the traditional method of virus inoculation followed by enzyme-linked immunosorbent assay.

A new binary vector (pT-LAB21) that contains a modification of the Aequorea victoria green fluorescent protein-GFP (erGFP7 INT ) as a reporter gene was constructed for the use in citrus transformation experiments. The gfp gene was excised from pLMNC95 plasmid and cloned into the pPZP212 binary vector containing an nptll gene for selection of putatively transformed shoots and the aadA gene for bacterial selection. pT-LAB21 was mobilized into EHA101, a hypervirulent disarmed strain of A. tumefaciens, by the freeze-thaw method. In order to test the plasmid, we performed transformation experiments on Carrizo citrange, 'Marsh' grapefruit, and 'Valencia' sweet orange by stem segment infection. Transformed plants of all three citrus cultivars were easily obtained, despite varying transformation efficiencies that were observed in these experiments. Highest efficiency of transformation was recorded for Carrizo citrange and the lowest for 'Valencia' orange. The possibility of detecting GFP fluorescence in seedlings by observing them under the microscope at an early stage and without doing any destructive assay has facilitated early screening of transgenic plants while maintaining their maximum vigor. To confirm the presence of foreign DNA in genomes of transformed citrus seedlings, we performed PCR and Southern analysis. This new binary vector is available for the transformation of citrus and other plants.

The response of silicon–silicon–CsI(Tl) telescopes, developed within the FAZIA collaboration, to fragments produced in nuclear reactions 84Kr+120-124Sn at 35 A MeV, has been used to study ion identification methods. Two techniques are considered for the identification of the nuclear products in the silicon stages. The standard ΔE−E one requires signals induced in two detection layers by ions punching through the first one. Conversely, the digital Pulse Shape Analysis (PSA) allows the identification of ions stopped in the first silicon layer. The capabilities of these two identification methods have been compared for different mountings of the silicons, i.e. rear (particles entering through the low electric field side) or front (particles entering through the high electric field side) side injection. The ΔE−E identification method gives exactly the same results in both configurations. At variance, the pulse shape discrimination is very sensitive to the detector mounting. In case of rear side injection, the identification with the “energy vs. charge rise time” PSA method presents energy thresholds which are significantly lower than in the case of front side injection.

The response of silicon–silicon–CsI(Tl) telescopes,developed within the FAZIA collaboration, to fragments produced in nuclear reactions 84Kr+120-124Sn at 35 AMeV, has been used to study ion identification methods. Two techniques are considered for thei dentification of thenuclear products in the silicon stages. The standard ΔE-E one requires signals induced in two detection layers by ions punching through the first one. Conversely, the digital Pulse Shape Analysis (PSA) allows the identification of ions stopped in the first silicon layer. The capabilities of these two identification methods have been compared for different mountings of thesilicons, i.e.rear (particles entering through the low electric field side) or front (particles entering through the high electric field side) side injection.The ΔE-E identification method gives exactly the same results in both configurations. At variance, the puls eshape discrimination is very sensitive to the detector mounting. In case of rear side injection, the identification with the‘‘energyvs.charge risetime’’ PSA method presents energy thresholds which are significantly lower than in the case of front side injection.

Dissipative 12 C + 12 C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at Laboratori Nazionali di Legnaro. A comparison to a dedicated Hauser-Feshbach calculation allows us to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24 Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain. Residual deviations from statistical behavior are observed in α yields and attributed to the persistence of cluster correlations well above the 24 Mg threshold for six-α decay.

The X6-1 xmatrix array transducer allows a completely new approach to the diagnostic ultrasound: it permits visualization of fetal heart in real time, without the need for gating, and it is unaffected by motion artefacts. It is obtained in real time, without any spatial reconstruction. The authors compared this technology with the traditional one in two case reports: a diagnostic doubt of small muscular ventricular septal defect was solved using this new technique; a diagnosis of complete atrioventricular septal defect was confirmed. Three-dimensional real-time imaging would seem very precise in the study of fetal heart: the defects were fully visualized from any angulations. This new technology is promising but from the authors' limited experience, there is no evidence to use it in routine practice. It should be very useful to commence a prospective study on fetuses at risk while testing the superiority of this technique.

Odd-even staggering effects on charge distributions are investigated for fragments produced in semiperipheral and central collisions of 112 Sn + 58 Ni at 35 MeV/nucleon. For fragments with Z :( 16 one observes a clear overproduction of even charges, which decreases for heavier fragments. Staggering persists up to Z ∼ 30. The staggering appears to be substantially independent of the centrality of the collisions, suggesting that it is mainly related to the last few steps in the decay of hot nuclei.

The reactions Ti-48+Ca-40 at 600, 450 and 300 MeV were employed at the Laboratori Nazionali di Legnaro (LNL) to investigate the charged particles and the Giant Dipole Resonance (GDR) decay of hot rotating Mo-88 nuclei. Some preliminary results about Light Charged Particles (LCP) distribution in coincidence with Evaporation Residues (ER) and fusion-fission events selection are shown

Ganglion cysts are benign masses that originate from mucinous degeneration of the connective tissues and are quite rare when arising from the knee joint. Symptoms are often represented by pain, joint tenderness, effusion and occasional swelling with a palpable mass in the popliteal region of the knee. Percutaneous aspiration followed by a corticosteroid injection of a ganglion cyst has either a diagnostic or therapeutic meaning and its guidance through ultrasound allows the operator to make more accurate the procedure, ensuring the correct placement of the needle inside the lesion. We report our experience in the treatment of a voluminous ganglion cyst of the posterior cruciate ligament performed through the ultrasound guidance in a symptomatic young patient.Le cisti gangliari sono formazioni benigne che derivano dalla degenerazione mucinosa del tessuto connettivo ed il loro sviluppo all’interno della caività articolare del ginocchio è relativamente rara. Esse si manifestano con dolore, versamento articolare, nonché occasionalmente con gonfiore e sottoforma di una massa palpabile a livello della regione poplitea. La loro aspirazione percutanea, eventualmente seguita da un’iniezione di corticosteroide, ha una valenza sia diagnostica che terapeutica e l’ausilio della guida ecografica permette all’operatore di rendere la procedura la più accurata possibile, assicurando il corretto posizionamento dell’ago all’interno della lesione. Vogliamo riportare la nostra esperienza nel trattamento percutaneo tramite guida ecografica di una voluminosa cisti gangliare del legamento crociato posteriore in una giovane paziente sintomatica.

The intrinsic depuration capability of a soil contaminated by polycyclic aromatic hydrocarbons (PAHs) originating from a contaminated industrial site was evaluated in this study by using different aerobic batch bioreactors: a slurry‐phase bioreactor, a blade‐agitated bioreactor, and a rotary vessel bioreactor. For each bioreactor, the disappearance of 14 target PAHs and of the total extractable organic matter was monitored. The three treatments exhibited rapid and extensive removal of the PAHs, which disappeared at different degradation rates according to their molecular weight and aromaticity degree. PAHs with two, three, and four aromatic rings were degraded in sequence, with average rates that generally decreased as the number of molecule rings increased. A slight increase in the bacterial biomass concentration and significant CO2 production were also observed during the time course of the treatments. Among the three treatments, the slurry‐phase system provides the most effective and fastest removal of...

Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z < 16) and velocity of the products were detected with full azimuthal acceptance at laboratory angles of 1-30 degrees. Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6-90 degrees. Central collisions representing about 1 % of the reaction cross section were selected by requiring high total transverse energy, but vanishing sideflow. The velocity space distributions and yields of the emitted fragments are reported. The data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the Quantum Molecular Model is presented., LateX text 62 pages, plus six Postscript files with a total of 34 figures, accepted by Nucl.Phys.A

iwm2001

XL Bormio

A 35-year-old woman was hospitalised at Policlinico Umberto I of Rome at 41 weeks’ gestation, for labour induction. Her previous medical and obstetric history, as well as the course of her current ...

Isospin mixing induced by Coulomb interaction has been measured in the compound nucleus Z = N = 40 80Zr at T∼2 MeV produced in a fusion‐evaporation reaction. The observable sensitive to the isospin purity of the compound nucleus is the Giant Dipole Resonance γ decay. The degree of mixing of the compound nucleus has been obtained via Statistical Model analysis of the measured γ spectrum.

Gas-liquid mass-transfer coefficient, holdup, and power consumption were measured in vessels stirred with multiple Rushton turbines. Water and glycerol-water solutions were used, with viscosity up to 70 mPa[center dot]s. For measuring k[sub L]a, the dynamic oxygen electrode technique was adopted. The following correlation is applicable for the water-glycerol solutions: k[sub L]a = C(P[sub g]/V)[sup [alpha]](U[sub s])[sup [beta]]([mu]/[mu][sub w,20])[sup [delta]]. For air-water systems the parameter C, while being the same as that for single impellers, is different from that for water-glycerol solutions. At equal P[sub g]/V and U[sub s], the mass-transfer coefficient for solutions of low glycerol concentration is higher than that for water, whereas it decreases at an increase in glycerol concentration. This behavior can be attributed to the noncoalescing characteristics of these solutions that are superimposed to the influence of viscosity. Cross-checking of k[sub L]a and holdup data confirms the interpretation given. The suitability of several equations available in the literature in interpreting the present data is also discussed.

The solids concentration distribution in solid—liquid suspensions in batch, mechanically stirred, vessels was investigated. The vessels were characterized by a high aspect ratio and were stirred with various combinations of multiple axial impellers. The suspensions were made of glass beads of various sizes in water and aqueous solutions of polyvinylpyrrolidone (PVP). The solids concentration was measured along the vertical axis of the vessel by means of an optical technique. The suspension efficiency of the impellers was compared on the basis of the departure of the solids concentration from suspension homogeneity (given as the variance of the solids concentration along the axis with respect to the mean) versus power consumption per unit mass. The solids concentration profiles were also modelled with the one-dimensional sedimentation—dispersion model having the Peclet number as a single adjustable parameter. For each geometrical configuration the Peclet number was correlated with the ratio of the tip speed to particle settling velocity and a Reynolds number based on the Kolmogorov theory. Once the difference in aspect ratio is taken into account, a single correlation for all the geometrical configurations could be obtained.

Solid distribution for solid—liquid suspensions was investigated under batch and semibatch conditions in completely closed tanks. The tanks had an aspect ratio equal to four and were stirred with multiple Rushton turbines. Spherical particles of different materials and sizes were used as the solid phase in various liquids. Average solid concentrations along the vertical axis of the tank were measured by means of an optical technique. The solid profiles can be fairly well modelled with the one-dimensional sedimentation-dispersion model. A correlation of the solid Peclet number with dimensionless groups that include physical and operating parameters was obtained for batch conditions. A procedure to apply the model also in the case of semibatch conditions was checked. The results also give additional evidence of the reduction of the settling velocities of solid particles in a stirred medium with respect to that in a quiescent liquid—at least for some operating conditions. The interaction between the particles and the turbulence field is proposed as a means to explain this behaviour.

After a short introduction to the COSMO (COnstellation of Small satellites for the Mediterranean basin Observation) system the paper presents and discusses the key results of a study-performed under contract to ESA-concerning the general problem of disaster monitoring and the utilization of COSMO for disaster warning and relief. COSMO's innovative optical and radar features-stressing high ground resolution and very frequent revisits of observed sites-seem well matched to the needs. Two representative disaster monitoring missions were selected to derive instruments and system requirements. These were compared to COSMO technical characteristics outlining which modifications to the baseline would be required to best meet the selected disaster monitoring missions.

Strictosidine synthase (STR) is a key enzyme in the biosynthesis of terpenoid indole alkaloids. This class of secondary metabolites harbours several pharmaceutically important compounds used, among other applications, in cancer treatment. Terpenoid indole alkaloid biosynthesis and expression of biosynthetic genes including Str1 is induced by fungal elicitors. To identify elicitor-responsive regulatory promoter elements and trans-acting factors, the single-copy Str1 gene was isolated from the subtropical plant species Catharanthus roseus (Madagascar periwinkle). Str1 upstream sequences conferred elicitor-responsive expression to the beta-glucuronidase (gusA) reporter gene in transgenic tobacco plants. Main enhancer sequences within the Str1 promoter region studied were shown to be located between -339 and -145. This region and two other regions of the promoter bound the tobacco nuclear protein factor GT-1. A G-box located around position -105 bound nuclear and cloned G-box-binding factors (GBFs). A mutation that knocked out GBF binding had no measurable effect on expression, which indicates that the G-box is not essential for the elicitor responsiveness of the Str1 promoter. No obvious homologies with promoter elements identified in other elicitor-responsive genes were observed, suggesting that the Str1 gene may depend on novel regulatory mechanisms.

The effect of suspension viscosity on power consumption in fully baffled stirred tanks is investigated phase solid-liquid two It is shown that the adoption of a propeir definition for the apparent viscosity makes it possible to correlate the data of single- and two-phase systems with the same power curve regardless of the flow regime.

The fluid-dynamic behaviour of a non-standard vessel working with air—water dispersions and stirred by means of multiple impellers was investigated. The study concerned the overall behaviour of the system as well as holdup and power consumption measurements. The overall behaviour can be modelled as a cascade of ideal stages with back-mixing; in the experimental range investigated the back-flow rate can be considered as independent of the presence of the dispersed gas phase. Holdup values are substantially the same as for the single impeller configuration; the applicability of published correlations for holdup prediction is discussed. The interpretation of power measurements confirms previous findings that power is unevenly consumed by the different turbines.

A previous investigation showing the influence of the viscosity of Newtonian liquids and flow rate of the feed on backmixing in baffled Mixing-Columns is extended here in order to take into account different geometrical arrangements and different rheologic behaviour of the fluids. In particular, both the influence of one of the most significant parameters which define the geometrical configuration of the apparatus (i.e. the diameter of the opening of the interstage baffle) and the backmixing characteristics of such systems when the fluid exhibits non-Newtonian pseudoplastic behaviour are considered. With reference to the first point, results, which agree well with less extensive results available in literature, are correlated in terms of dimensionless backflow rate, rotational and flow Reynolds numbers and a shape factor. With reference to the second point, a suitable “apparent” viscosity is defined and the possibility of using the general correlation introduced for Newtonian fluids even for pseudoplastic fluids is shown.

A study has been made of the influence of catalyst concentration profiles on isothermal continuous slurry reactor performance. Solid catalyst behaviour was modelled with the one dimensional sedimentation-dispersion model and that of the liquid with the one dimensional dispersion model. The Power-law kinetic model as well as Michaelis-Menten and a form of Langmuir-Hinshelwood kinetics were considered. The results of the computations are given in terms of departures of the exit concentration obtained with a selected, non-uniform, catalyst distribution with respect to constant catalyst profile (reference case). Only for intermediate mixing conditions were differences in the exit concentration found. These differences are usually negligible for power law and Michaelis-Menten kinetics (especially for conversion not very high); on the contrary, they became meaningful for the Langmuir-Hinshelwood—at least for some ranges of the parameters. The existence of an optimal catalyst distribution was also discu...

Little attention has so far been devoted to characterizing fluid-dynamic behaviour of multiple-impeller mixers which are often implicitly modelled as perfectly stirred tanks. In the present paper a study is made of this type of equipment—stirred with four turbines; either six- or four-flat-blade disc turbines were used. Mean local concentration inside the mixers was measured and experimental pulse-response curves were compared with the theoretical curves corresponding to two one-parameter models (i.e., a cascade of ideal stages with backmixing and one-dimensional diffusion model) and to perfect mixing. The results of both analyses show that both the one-parameter models considered represent the actual fluid-dynamic behaviour quite satisfactorily and the model of perfect mixing can be considered only as a first approach for macromixing modelling purposes. Extensive investigation was then carried out in order to determine the dependence of the characteristic parameter of the stagewise model on operating con...

An experimental investigation was carried out in order to test the suitability of fluid-dynamic models for the interpretation of data for multistage mixer columns of the RDC and Mixco types. Mean local concentration values in the inside of the compartments were measured and experimental impulse response curves were systematically compared with the theoretical curves corresponding to the models. Furthermore the results of static and dynamic methods of measurement of model parameters were compared. In order to bring out possible causes of error due to buoyancy phenomena, feed was introduced either into the bottom stage (ascending flow) or the top stage (descending flow). Local inspection and comparison of experimental and theoretical dynamic curves as well as results of different methods for measuring the amount of backmixing confirm the great reliability of the model of a cascade of ideal tanks with backmixing for the systems considered.