Alessandro Innocenti

Organosilane‐Induced Synthesis and Functionalization of Sulfur‐Containing Compounds

Reactions of organothiosilanes with organic substrates generally lead to delivery of a sulfur moiety onto the target molecule, the precise outcome being related to the structure of the silyl sulfide used. Aromatic and aliphatic silyl sulfides react with carbonyl compounds under acidic or basic conditions to afford thioacetals and thioketals, but reactions with more activated compounds such as α,β-unsaturated acylsilanes give the Michael adducts, which represent versatile intermediates in organic synthesis. Silyl sulfides can also participate in substitution reactions of silyl enol ethers to afford vinyl sulfides. On the contrary, hexamethyldisilathiane reacts with various carbonyl compounds under the catalysis of CoCl2·6H2O or CF3SO3SiMe3 with thionation of the carbonyl unit, thereby providing a general access to thioketones and thioaldehydes, which can be trapped in situ by dienes. The use of CF3SO3SiMe3 in the reaction with cyclohexadiene gives rise to the interesting feature that stereopredetermined access to either the endo or the exo isomer can be obtained. Furthermore, when using aromatic or heteroaromatic o-azidoaldehydes, the reactivity of hexamethyldisilathiane may be finely tuned to drive the reaction towards the synthesis of o-azidothioaldehydes, fused isothiazole ring systems, or aromatic and heteroaromatic o-amino aldehydes and o-amino thioaldehydes. Lastly, by taking advantage of the high reactivity of the C−Si bond under fluoride ion catalysis, selective regiospecific thiophilic functionalizations of thioketones, dithioesters, trithiocarbonates, and their sulfines by various organosilanes such as allylsilanes, benzylsilane, and α-hetero-substituted silyl nucleophiles can be realized.

Aesthetic Calf Augmentation with Silicone Implants

So-called “skinny legs” are commonly held to be aesthetically negative in both men and women. Taking care of ones body in terms of aesthetics is a practice that is continuously spreading and being refined to the smallest details. Indeed, a leg with underdeveloped muscles, lacking a sculptured look is considered to be unattractive and therefore deserving of surgical correction. The present article illustrates a surgical technique for correcting this marginal, yet valid, aesthetic complaint as well as the relative indications, methods, and preliminary results that have been obtained in 11 patients.

Discussion: Surgical Management of Gynecomastia—Subcutaneous Mastectomy and Liposuction

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Synthesis of enantiomerically pure anti-1,2-diaryl and syn-1,2-alkylaryl vic-selenoamines.

Phenylselenyl benzylcarbanion stabilized by an (S)-2-p-tolylsulfinyl group evolves in a highly stereoselective way in the reactions with (S)-N-(p-tolylsulfinyl)imines at -98 °C affording diastereomerically pure 1,2-selenoamino derivatives in good yields. The syn or anti relationship of the obtained compounds depends on the alkyl or aryl character of the imine. They are easily transformed into enantiomerically pure (1R,2S)-1-aryl[or (1S,2S)-1-alkyl]-2-(phenylseleno)-2-phenylethylamines by reaction with t-BuLi and subsequent methanolysis of the generated sulfinamide derivatives with TFA.

Comment to “No-Drain Single Incision Liposuction Pull-Through Technique for Gynecomastia”

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Numerical analysis of the dynamic flame response of a spray flame for aero-engine applications

Incoming standards on NO x emissions are motivating many aero-engine manufacturers to adopt the lean burn combustion concept. One of the most critical issues affecting this kind of technology is the occurrence of thermo-acoustic instabilities that may compromise combustor life and integrity. Therefore the prediction of the thermo-acoustic behaviour of the system becomes of primary importance. In this paper, the complex interaction between the system acoustics and a turbulent spray flame for aero-engine applications is numerically studied. The dynamic flame response is computed exploiting reactive URANS simulations and system identification techniques. Great attention has been devoted to the impact of liquid fuel evolution and droplet dynamics. For this purpose, the GE Avio PERM (partially evaporating and rapid mixing) lean injection system has been analysed, focussing attention on the effect of several modelling parameters on the combustion and on the predicted flame response. A frequency analysis has also been set up and exploited to obtain even more insight on the dynamic flame response of the spray flame. The application is one of the few in the literature where the dynamic flame response of spray flames is numerically investigated, providing a description in terms of flame transfer function and detailed information on the physical phenomena.

Discussion: “Long-Term Follow-Up of Recurrence and Patient Satisfaction After Surgical Treatment of Gynecomastia”

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Aziridines Ring Opening by Silyl Chalcogenides: a Stereoselective Access to Polyfunctionalized Molecules as Precursor of Sulfurated and Selenated Heterocycles

GRAPHICAL ABSTRACT Abstract Aziridines react efficiently with bis(trimethyl)silyl-sulfide and -selenide to afford a direct access to β-amino thiols and selenols. Synthesis of 2,4-disubstituted 1,3-selenazolidines is obtained through reaction of 1,2-amino selenols with aldehydes.

Design Improvement Survey for NOx Emissions Reduction of a Heavy-Duty Gas Turbine Partially Premixed Fuel Nozzle Operating With Natural Gas: Numerical Assessment

As government regulations become increasingly strict with regards to combustion pollutant emissions, new gas turbine combustor designs must produce lower NOx while also maintaining acceptable combustor operability. The design and implementation of an efficient fuel/air premixer is paramount to achieving low emissions.Options for improving the design of a natural gas fired heavy-duty gas turbine partially premixed fuel nozzle have been considered in the current study. In particular, the study focused on fuel injection and pilot/main interaction at high pressure and high inlet temperature.NOx emissions results have been reported and analyzed for a baseline nozzle first. Available experience is shared in this paper in the form of a NOx correlative model, giving evidence of the consistency of current results with past campaigns.Subsequently, new fuel nozzle premixer designs have been investigated and compared, mainly in terms of NOx emissions performance. The operating range of investigation has been preliminarily checked by means of a flame stability assessment. Adequate margin to lean blow out and thermo-acoustic instabilities onset has been found while also maintaining acceptable CO emissions.NOx emission data were collected over a variety of fuel/air ratios and pilot/main splits for all the fuel nozzle configurations. Results clearly indicated the most effective design option in reducing NOx. In addition, the impact of each design modification has been quantified and the baseline correlative NOx emissions model calibrated to describe the new fuel nozzles behavior.Effect of inlet air pressure has been evaluated and included in the models, allowing the extensive use of less costly reduced pressure test campaigns hereafter. Although the observed effect of combustor pressure drop on NOx is not dominant for this particular fuel nozzle, sensitivity has been performed to consolidate gathered experience and to make the model able to evaluate even small design changes affecting pressure drop.Copyright

Synthesis of A New Class of Sulfurated and Selenated Silyl Heterocycles

Abstract 2-Trimethylsilyl-1,3-thiaselenolanes and 2-trimethylsilyl-1,3-oxaselenolanes can be accessed through the reaction of a silyl acetal with β-mercapto- and β-hydroxyselenols under Lewis acid conditions. GRAPHICAL ABSTRACT