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Gas phase ion-molecule reactions in systems containing CH 3 GeH 3 and oxygen, or ammonia, or unsaturated hydrocarbons (C 2 H 4 , C 3 H 6 , C 3 H 4 ) have been studied by Fourier-transform mass spectrometry and high-pressure mass spectrometry. The self-condensation processes of CH 3 GeH 3 as well as the effects of the nature and the concentration of the reagent, and of the total pressure of the system on the formation of new GeO, GeN and GeC bonds are investigated. For each system the reaction pattern is presented and the gas phase reactivity of CH 3 GeH 3 compared with that of GeH 4 towards the same reagents. The formation of ionic species containing new GeC bonds observed in the CH 3 GeH 3 /unsaturated hydrocarbons systems is discussed in relation to the preparation of amorphous germanium carbides, which are promising materials for photovoltaic applications.

Bulk YBCO samples have been prepared for the first time by using Metal-Organic Deposition (MOD) technique.Solutions of Y, Ba and Cu neodecanoates have been used in order to obtain directly YBCO powders (not exactly, but approximately stoichiometric) after a back-up and a pyrolysis step at 500°C. The powders have been successively pressed and subjected to two annealing steps in order to built up the YBCO structure, to increase grain dimensions and to adjust oxygen stoichiometry. The samples, which are disk-shaped, 1 mm thick and 1 cm wide, display a sharp superconducting transition at 93 K and possess a relatively large critical current.Diffraction patterns indicate a strong degree of orientation of (a,b) planes along the surface. The superconducting gap has been measured by SIS' tunneling with Nb and by investigation on SS' Andreev reflection.

Objective: The use of additional US markers during the first trimester screening permitted an increase of sensibility of the test and/or reduction of the false positive rate. The objective of this study was to analyze the feasibility and the duration of a complete structural examination of the fetus. Methods: All examinations included evaluation of nuchal translucency, nasal bone, tricuspid valve, ductus venosus, facial angle, head, brain, stomach, bladder, spine, kidneys, abdominal wall, umbilical arteries and extremities. When was not possible to conclude the examination due to the fetal position the patient was invited for a walk and re-examined later. When the visualization of the fetal structures was not satisfactory due to increased maternal MBI or retroverted uterus a TV examination was added. Facial angle was measured in 2D sections or volumes were acquired after a midsagittal section was obtained. Results: In the period May 2008 – January 2009, 838 screening test were performed. Mean CRL was 62mm. The mean duration was 16,8 (5–60) min. TV examination was needed in 12% of cases. 62% of the examinations were done in a single section while 10% were seen in 3 or more sections. The duration was increased with maternal BMI, additional TV approach and number of sections performed. The need of TV scan was associated with maternal BMI while the number of US sections depended on the fetal position. Fetal bladder and kidneys were the most frequently difficult to assess structures. Nuchal translucency, nasal bone and tricuspid valve were successfully examined in all scans. Ductus venosus waves were not satisfactory in 1% of our series. Facial angle was not feasible in 2,5% of the cases. Conclusion: A complete examination of all the fetal structures and of all US markers for abnormalities is feasible with a mean duration of 16–17min. The only factors increasing the time of the examination were maternal BMI and fetal position.

Objective: To evaluate the reproducibility and accuracy of the diagnosis of fetal heart conditions using a standardized methodology of analysis of STIC volume datasets (VD) Methods: Two fetal echocardiographers were invited to participate in the study. VD from 65 patients was selected. Most of the cases were submitted by Internet through our telemedicine program based on STIC (Tele-STIC). All the acquisitions were taken in a transverse view, beginning at the level of the four-chamber view, with an angle of acquisition necessary to include information from the upper abdomen until the upper mediastinum. There were 13 normal and 52 abnormal cases. In 37 of the cases, only one VD was included. No patient in the study had more than 2 VDs. Only 10 cases had color Doppler STIC acquisitions. Each of the examiners analyzed the VD independently and only received information regarding the gestational age. Each volume was specifically displayed in the acquisition plane as full screen. They were able to adjust the zoom, gain, and heart rate and to scroll through the A-plane. No multiplanar manipulation or rendering was allowed. Four categories were used to denote the degree of seriousness of error. Category 1 was a serious error and categories 2–4 were defined as partially correct diagnoses Results: Examiners did offline evaluations of the cases in 7 hours. There was a complete agreement between the prenatal and the postnatal diagnosis in 74% and 69% of the cases (p = 0.5598). From the normal cases, they were correct in 84%–69% (p = 0.3519) and in 71%–69% of the abnormal cases (p = 0.8303). Examiners have minor discrepancies with the postnatal diagnosis in 14–17 of the cases (p = 0.8277) and major discrepancies in 3 cases each one of them Conclusions: In experienced hands, a standardized methodology of analysis of STIC volume datasets using transverse sequential views is a reliable, reproducible and accurate tool for prenatal diagnosis, particularly for the telemedicine program.

sinus, the Torcula Herophili, dural folds of the inferior attachments of the falx cerebelli, or bridging arachnoid septations. Through improved knowledge of posterior fossa embryology, anatomy and malformations and our own observations in fetuses and neonates, we believe that these septa represent a remnant of Blake’s pouch, a normal dorsal extension of the developing 4th ventricle. We also demonstrate the probable relationship between these septa, the Dandy-Walker continuum, mega cisterna magna and Blake’s pouch cyst. Results: Observations that we will demonstrate on fetal and neonatal cranial sonography include

Objectives: To assess the characteristics and the outcome of right and double aortic arch without any associated major intracardiac defect. Methods: Observational trial of 16 fetuses with a confirmed diagnosis of right aortic arch (14 cases) or double aortic arch (2 cases). All of them underwent fetal echocardiography and detailed anatomic scan. Karyotyping was performed in 13/16 cases; FISH analysis to detect 22q11 microdeletion in 12/16 cases. The following variables were retrieved from databases and evaluated: indication for referral, gestational age at diagnosis, associated anomalies, fetal growth restriction, fetal/neonatal outcome. Results: Sixteen fetuses were identified with a median gestational age at diagnosis of 26 weeks (range 21–35). Arch anomalies included: double aortic arch (2 cases, 12.5%), right aortic arch with an aberrant left subclavian artery (5 cases, 31.3%), and right aortic arch with mirror image branching (9 cases, 56.2%). In all but 2 cases the correct diagnosis was made at the first US examination; in the remaining 2 cases at the subsequent follow up examination. In two fetuses a ventricular septal defect was associated. Extracardiac anomalies were found in six cases, and were associated with 22q11 microdeletion in two cases. The 22q11 microdeletion was present in 3/12 cases. Fetal growth restriction was present in 3 cases. Fetal/neonatal outcome was as follows: 3 terminations of pregnancy, 1 post-neonatal death and 12 neonates alive. One case was already symptomatic within the first 3 months of life. Conclusion: Although there are only few reports, because of its not easily detection and rarity, right and double aortic arch can be characterized in prenatal life. However in 2/16 cases the correct diagnosis was made at the subsequent follow up examination. The use of 3-D PDU rendering facilitates significantly the spatial understanding of these anomalies.

Results: DC was detected in 19 cases (0.3%) and premature closure of FO in 2 (0.03%). Two fetuses with DC presented with ascites and polyhydramnion. In two cases DC coexisted with CALM. Once there was DC of one of the twins. DC was present at mean 33 wks of gestation. In 12 cases there was maternal pharmacotherapy. Abnormal DC was present at the mean on 3rd day of pharmacotherapy. In addition to DC there were also other abnormalities: myocardial hypertrophy, tricuspid valve regurgitation, pulmonary regurgitation, pericardial effusion, or disproportion. Two fetuses presented arrhythmias. Mean 25 days after DC there was or vaginal delivery (10×) or CS (9×). Mean birth weight was 3074, mediana of Apgar score-9. There was 17 survivors. In neonatal echo in all cases still right ventricular hypertrophy was present with no clinical adverse outcome. During the same period 2 cases of premature closure of FO were observed. The first one presented with ascites at 28 wks of gestation and died in utero. The second one presented with acute cardiomegaly, disproportion, right ventricular wall hypokinesis and tricuspid valve regurgitation, had emergency CS at 35 wks of gestation. This baby was discharged home at 15th day of life with no clinical symptoms. Conclusions: 1. Premature DC usually caused by maternal pharmacotherapy with transient myocardial hypertrophy, TR, disproportion, but without cardiomegaly and this anomaly was reversible during fetal life. 2. Premature closure of foramen ovale was very rare phenomenon presented with acute cardiomegaly, right ventricle dyskinesis, TR and should prompt to emergency CS.

The radiation-induced synthesis of gdot; 2 (η 2 -cyclohexyne)hexacarbonyl dicobalt (CoCo) and gdot; 3 (2-cyclopenten-1 methylidine)-cyclo-tris(tricarbonyl cobalt)(3CoCo) from benzene and Co 2 (CO) 8 is reported. The metal carbonyl species act as traps for some of the radiation-induced excited species.

The gas phase ion-molecule reactions of GeH 4 with some carbon-containing compounds (CO, CO 2 , and C 2 H 4 ) have been studied by high pressure mass spectrometry and Fourier transform mass spectrometry. The effects of the total pressure and of the relative concentrations of the reagent gases on the ion pattern are reported. In the presence of CO and CO 2 , GeH n CO + or GeH n CO 2 + , GeH n O + , and GeH n C + ions are observed, all of which show very low abundances. In contrast, condensation processes of GeH 4 with C 2 H 4 give GeC n H m + ( n = 1–4) species, in very high yield for n = 1, 2 but lower for n = 3, 4. For all three systems, reaction mechanisms are suggested and are discussed in relation to the preparation of amorphous materials containing germanium carbides for photovoltaic applications.

Ni(CO)4 reacts with ionic species produced by the γ-radiolysis of n-butane and n-pentane modifying ion-molecule reaction paths. The major effect is a tenfold increase of the ethylene yield and a loss of other light products. The effect of ionic and radical reactions with Ni(CO)4 is briefly discussed.

Positive chemical ionization mass spectra of arenetricarbonylchromium compounds with propene, benzene and toluene, at about 0.5 torr, are reported. Protonation, charge exchange, fragmentation and CO substitution processes occur for all these complexes. The abundances of the [M + H]+ and substituted ions strongly depend on the reagent gas and, for any given gas, on the coordinated arene. The effects of the nature of the reagent gas and of the coordinated arene on the ion abundances are discussed and reaction mechanisms suggested.

H2, Ge2H6 and a solid material (GeHx)n (x = 0.55–1.81) are produced by γ-radiolysis of GeH4. The relative amount of all the products and the composition of the solid are reported vs the pressure of GeH4 in the sample and the radiation dose. The composition of the solid approaches the formula GenH2n as the pressure increases while the production of H2 and Ge2H6 decreases.

Doubly charged ions observed in the mass spectra of trimetal carbonyl compounds of the iron group and of their derivatives at different ionizing energy are reported. In the case of Os 3 (CO) 12 , Ru 3 (CO) 12 , RuOs 2 (CO) 12 and Ru 2 Os(CO) 12 the abundances of the doubly charged ions decrease gradually when osmium atoms are substituted by ruthenium atoms and when ionizing electrons energy is decreased. They follow a characteristic trend in which the highest charge is transported by fragments containing a number of carbonyl groups which increases with decreasing ionizing energy. The mass spectrum of Fe 3 (CO) 12 contains very weak doubly charged species. H 2 Os 3 (CO) 12 exhibits a behaviour similar to that of Os 3 (CO) 12 , while Os 3 (CO) 10 Br 2 and Os 3 (CO) 12 Br 2 show that different structures do not appreciably affect the occurrence of doubly charged ions. The strong increase of the stabilization of doubly charged species, observed in the mass spectra of Fe 3 (CO) 8 [C 2 (C 6 H 5 ) 2 ] 2 , Ru 3 (CO) 8 [C 2 (C 6 H 5 ) 2 ] 2 and Os 3 (CO) 8 [C 2 (C 6 H 5 ) 2 ] 2 , shows a drastic influence of the organic ligands superimposed to that of the nature of metal atoms. In the mass spectrum of Os 3 (CO) 8 [C 2 (C 6 H 5 ) 2 ] 2 at 70 eV a rather strong [M  8CO] 3+ is observed.

The addition of Ni(CO) 4 and Fe(CO) 5 to the C 4 H 10 + recoil T system causes remarkable increase of ethylene-T and light hydrocarbons-T yields. The effect of metal carbonyls on products yield variation has been ascribed to an intermediate containing the metal and the radicals produced in the reactions. By the use of inert moderators and pressure effect, which enhance the radical density, the essential role of T• and alkyl radicals as limiting reactants is discussed.

A method is described for the evaluation of the natural/synthetic ratio in citric acid samples. The method is based on measurements of the activity of carbon-14 present in citric acid of natural origin. The parameters that affect the radiocarbon counting (background emission, scintillation quenching and relative efficiency) are discussed. Two different procedures are described which can also be applied to the evaluation of the natural/synthetic origin of other carbon-containing compounds.

A simple method for the radio-gas chromatographic analysis of species that contain labile tritrium is described. The method can be also applied to mixtures that contain, in addition to other tritium-labelled compounds, one labile tritium species. The procedure consists of the use of an exchangeable carrier or a mixture of an inert carrier with an exchangeable compound. The analyses of some test mixtures are reported and the applicability of the method is briefly discussed.

The heterometallic cluster (η5-C5H5)NiOs3(μ-H)3(CO)9 is decomposed under H2 to metal particles on the inert support of a gas chromatographic column. The column is used as a catalytic reactor to hydrogenate CC and CO multiple bonds and to study the H-for-Cl substitution reactions on chlorinated hydrocarbons. The performance of such a column and its possible use are briefly discussed.

In this paper we study a first-order language that allows to express and prove properties regarding the sharing of variables between non-ground terms and their types. The class of true formulas is proved to be decidable through a procedure of elimination of quantifiers and the language, with its proof procedure, is shown to have interesting applications in validation and debugging of logic programs. An interesting parallel is pointed out between the language of aliasing properties and the first order theories of Boolean algebras.

An accurate gas-phase acidity for germane (enthalpy scale, equivalent to the proton affinity of GeH3 −), ΔH acid o(GeH4) = 1502.0 ± 5.1 kJ mol−1, is obtained by constructing a consistent acidity ladder between GeH4, and H2S by using Fourier transform-ion cyclotron resonance spectrometry, and 0 and 298.15 K values for the first bond dissociation energy of GeH4 are proposed: D0 o(H3Ge-H) = 352 ± 9 kJ mol−1; D o(H3Ge-H) = 358 ± 9 kJ mol−1, respectively. These results are compared with experimental and theoretical data reported in the literature. Methylgermane was found to be a weaker acid than germane by approximately 35 kJ mol−1: ΔH acid o = 1536.6 kJ mol−1.

This paper is an overview of our results on the application of abstract interpretation concepts to various problems related to the verification of logic programs. These include the systematic design of semantics modeling various proof methods and the characterization of assertions as abstract domains. We derive an assertion based verification method and we show two instances based on different assertion languages: a decidable assertion language and CLP used as an assertion language.

The negative ion mass spectra of Ni(LH)2 (where LH2 is glyoxime, methylglyoxime, dimethylglyoxime and diphenylglyoxime), in the presence of ammonia or methane at 0.5 torr, are reported and compared with the spectra of the free ligands. In each case, the base peak of the complex is the molecular negative ion and the extent of fragmentation was found to decrease gradually going from the glyoximato to the diphenylglyoximato derivative. In the chemical ionization mass spectra of the free ligands, the [M]− ion is absent in all cases. The base peak is [M  H]− for methylglyoximine, dimethylglyoxime and diphenylglyoxime and [M  H  H2]− for glyoxime. The fragmentation occurs largely by loss of H, OH, H2O and NO species. The positive ion chemical ionization mass spectra of the same complexes show very abundant [M + H]+ and [M]+ ions and weak fragments, whilst a rather high fragmentation is observed for the corresponding free ligands.

The positive chemical ionization mass spectra, with ammonia and isobutane at 0.5 torr of (η6-arene)Cr(CO)3, where arene is C6H5COMe, C6H5COEt, C6H5COC3H7, C6H5COCMe3, 2-MeC6H4COC3H7, C6H5COOMe, C6H5CH2 COEt, C6H5Me and 1,3,5-Me3C6H3 are reported. All these compounds exhibit [M + H]+ as base peak, with isobutane. In the presence of ammonia, [M + NH4]+ is the most abundant ion, when the arene is a ketone or an ester and the addition site is suggested to be the ligand. Conversely [M + H]+ is the base peak when arene is toluene and mesitylene and the protonation site is likely to be the metal atom. In the presence of ammonia, ions such as [M — 3 CO + NH3]+ and [M — 3 CO + 2 NH3]+ are also observed and their abundances strongly depend on the pressure of the reagent gas.

The positive ion chemical ionization mass spectra, with ammonia, dimethylamine and methane at 0.5 torr, of RR'C2Co2(CO)6, where alkyne is HC2CH2OH, HC2CMe2OH, HC2CH2NMe2, HC2Ph, PhC2Ph, MeC2Me and MeO2CC2- CO2Me are reported. The nature of the coordinated ligands affects the ion affinity and the addition site for the reagent gas ion. In the complexes with alkynes containing appropriate functional groups, such as hydroxo- and amino-groups, addition of the ionic species occurs on the ligand, whereas it occurs on one of the cobalt atoms when the ligand is phenylacetylene, diphenylacetylene and 2-butyne. Ammonia and dimethylamine also give substitution reactions in which neutral reagent gas molecules replace carbonyl groups of metal containing ions. A comparison between the spectra of the free ligands and those of the corresponding carbonylcobalt complexes is also discussed.

The negative ion chemical ionization mass spectra, with ammonia and methane as reagent gases, of the (η6-arene)Cr(CO)3 complexes, where the arene is C6H5COCH3, C6H5COC2H5, C6H5COC3H7, C6H5COC(CH3)3, 2-CH3C6H4COC3H7, C6H5COOCH3, C6H5CH3, 1,3,5-(CH3)3C6H3 and C6H5CH2COC2H5, are reported. Similar behaviour is observed with the two reagent gases, but ammonia shows a much higher abundance for the ions produced by reactions of [NH2]− with sample molecules. The compounds containing the C6H5CO group display an abundant [M]− ˙, whereas the other compounds exhibit [MH]− as base peak, produced by ion/molecule reactions. A comparison of the negative ion chemical ionization mass spectra of the (η6-arene)Cr(CO)3 complexes with those of the corresponding ligands shows the strong electron withdrawing power of the Cr(CO)3 group in the gas phase.

High pressure and Fourier transform mass spectrometry have been used to study the ion-molecule reactions of germanium-containing ions with oxygen, ammonia, and GeH4 itself. The effects of the total pressure and of the ratio between GeH4 and oxygen or ammonia are reported. In self-condensation reactions the most reactive species are Ge+ and GeH2P+, which give dimer ions containing an even number of hydrogen atoms. Formation of GeHnO2+ (n = 0, 1) and GeHnO+ (n = 0−3) ions is observed in GeH4/O2 mixture. The most abundant species is GeHO+, which originates in the reaction of Ge2H2+ with one O2 molecule, as demonstrated by FTMS. High pressure experiments suggest that oxygen-containing ions are also formed by pathways involving monogermanium ions. Analogous behaviour is observed in the GeH4/NH3 mixtures, where GeNHn+ (n = 2, 3, 4, 6) ions are formed in higher abundances than GeHO+ (n = 1−3) ions under similar conditions.

TGA, MS and DSC of a solid polymeric Ge hydride, obtained by γ-radiolysis of GeH 4 , are reported. Upon heating, it undergoes two successive weight losses at 463 and 1173 K. At 948 K two crystal phases are formed, one of them is pure germanium. Some comparisons with a-Ge: H produced via RF sputtering or glow discharge are reported.

The radiation-induced synthesis of gdot; 2 (η 2 -cyclohexyne)hexacarbonyl dicobalt (CoCo) and gdot; 3 (2-cyclopenten-1 methylidine)-cyclo-tris(tricarbonyl cobalt)(3CoCo) from benzene and Co 2 (CO) 8 is reported. The metal carbonyl species act as traps for some of the radiation-induced excited species.

Gaseous mixtures of phosphine and germane have been investigated by ion trap mass spectrometry. Reaction pathways together with rate constants of the main reactions are reported. The mechanisms of ion/molecule reactions have been elucidated by single and multiple isolation steps. The GeHn+ (n = 1–3) ions react with phosphine to give GePHn+ (n = 2–4) ions. The GePH4+ ion further reacts with GeH4 to yield Ge2PH6+. The GePHn+ (n = 2–4) mixed ionic family also originates from the P+ phosphine primary ion, as well as from the P2Hn+ (n = 0–3) secondary ions of phosphine reacting with neutral germane and from Ge2H2+ reacting with phosphine. The main reaction pathways of the PHn+ (n = 0–2) ions with GeH4 lead to the formation of the GeH2+ and GeH3+ ionic species. Protonation of phosphine from different ionic precursors is a very common process and yields the stable phosphonium ion, PH4+. Trends in total abundances of secondary GePHn+ (n = 2–4) ions as function of reaction time for different PH3/GeH4 pressure ratios show that excess of germane slightly affects the nucleation of mixed Ge-P ions.

Phosphine/silane mixtures have been investigated by ion trap mass spectrometry, and reaction pathways together with rate constants of the main reactions are reported. Mechanisms of ion−molecule reactions have been elucidated by single and multiple isolation steps, and exact mass measurements have been performed by Fourier transform mass spectrometry. The SiHn+ (n = 0−3) ions react with phosphine to give SiPHn+ (n = 1−4) ions. These ions further react and yield SiP2Hn+ (n = 2−5) and Si2PHn+ (n = 3−7) ions, which, in turn, react following different pathways with silane or phosphine to give Si2P2Hn+ (n = 5, 6, 8) and Si3PHn+ (n = 5−7), respectively. Mixed SiPHn+ (n = 1−4) ions also originate from the PHn+ (n = 0, 1) phosphine primary ions, as well as from the P2Hn+ (n = 0−3) secondary ions of phosphine. Protonation of phosphine from several ionic precursors is a very common process and yields the stable phosphonium ion, PH4+. Trends in total abundances of tertiary SiP2Hn+ (n = 2−4) and Si2PHn+ (n = 3−7) ions...

The silane/propane and silane/propene gaseous mixtures have been investigated by ion trap mass spectrometry. The variations of ion abundances observed under different partial and total pressures are reported. The mechanisms of ion/molecule reactions have been elucidated by successive isolation steps. Moreover, the rate constants for the main processes have been experimentally measured and compared with the collisional rate constants to determine the reaction efficiencies. A great number of processes have been observed in SiH 4 /C 3 H 6 leading to the formation of silicon and carbon containing ions with high efficiency, whereas propane and silane give very few ion products with low efficiencies. Chain propagation in the SiH 4 /C 3 H 6 system gives clusters of increasing size, such as Si 2 C 2 H 7 + and Si 3 CH 7 + , with rather high efficiencies starting from silicon containing ions and neutral propene.

The T + CH3SiD3 system has been studied to evaluate the effect of reactant pressure on parent-T yield. The substitution yields for C—H and Si—D bonds have been found to be in the ratio 1 : 1.7. The decomposition rate of the excited parent-T has been calculated on the basis of the above ratio and compared with experimental yields at low pressure. Hypotheses to explain the discrepancy between calculated and experimental values are discussed.

This paper presents an experimental method to estimate the structural damping. In aerospace, but also in other sectors, the study of structural damping is very important be- cause it characterizes the structural dynamic behaviour. The vibrations and more generally how they are transmitted in the structure are a topic of great interest for aircraft noise sup- pression (Structure-Borne noise) and also for other aerospace applications (eg. space launch and satellite) wherein the high frequencies vibration are very dangerous. Many methods for damping measurements in literature are based on modal behaviour of the structure, so the maximum frequency at which they can operate is very limited. The proposed method is able to overcome this limitation and brings some advantages in the study of damping parameters. This method has been implemented starting from the Impulse Response Decay Method (IRDM) and allows the study at high frequencies and high modal density conditions. The method is based on the application of Hilbert transform directly on the time history of the signal also when it is not possible to isolate the structural modes, thus overcoming the limitations of the methods mentioned above. During the studies it has been shown how, in the tests, the choice of an impulsive excitation is very signicant in order to reduce the computational complexity of the extraction algorithm. In fact this choice allows to release the study by the frequency response of the structure, allowing to operate directly in time domain. Some devices operating on the function returned by the Hilbert transform permitted to achieve a reduction of numerical errors obtaining results much more reliable and closer to reality. Finally, some results obtained for a fuselage composite skin have been reported, as example of application of aforesaid method.