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61.
Michael Kleinman Alessandro Achille Stefano Soatto Jonathan C. Kao 《Entropy (Basel, Switzerland)》2021,23(7)
We introduce the Redundant Information Neural Estimator (RINE), a method that allows efficient estimation for the component of information about a target variable that is common to a set of sources, known as the “redundant information”. We show that existing definitions of the redundant information can be recast in terms of an optimization over a family of functions. In contrast to previous information decompositions, which can only be evaluated for discrete variables over small alphabets, we show that optimizing over functions enables the approximation of the redundant information for high-dimensional and continuous predictors. We demonstrate this on high-dimensional image classification and motor-neuroscience tasks. 相似文献
62.
Determination of selected endocrine disrupting compounds in human fetal and newborn tissues by GC-MS
Achille Cappiello Giorgio Famiglini Pierangela Palma Veronica Termopoli Anna Maria Lavezzi Luigi Matturri 《Analytical and bioanalytical chemistry》2014,406(12):2779-2788
Endocrine disrupting compounds (EDCs) include organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), carbamate pesticides, and plasticizers, such as bisphenol A (BPA). They persist in the environment because of their degradation resistance and bioaccumulate in the body tissues of humans and other mammals. Many studies are focused on the possible correlation between in utero exposure to EDCs and adverse health hazards in fetuses and newborns. In the last decade, environmental pollution has been considered a possible trigger for Sudden Infant Death Syndrome (SIDS) and Sudden Intrauterine Unexplained Death Syndrome (SIUDS), the most important death-causing syndromes in fetuses and newborns in developed countries. In this work, a rapid and sensitive analytical method was developed to determine the level of OCPs and OPPs, carbamates, and phenols in human fetal and newborn tissues (liver and brain) and to unveil the possible presence of non-targeted compounds. The target analytes where selected on the basis of their documented presence in the Trentino-Alto Adige region, an intensive agricultural area in northern Italy. A liquid-solid extraction procedure was applied on human and animal tissues and the extracts, after a solid phase extraction (SPE) clean-up procedure, were analyzed by gas chromatography coupled to a quadrupole mass spectrometric detector (GC-qMS). A GC-TOFMS (time-of-flight) instrument, because of its higher full-scan sensitivity, was used for a parallel detection of non-targeted compounds. Method validation included accuracy, precision, detection, and quantification limits (LODs; LOQs), and linearity response using swine liver and lamb brain spiked at different concentrations in the range of 0.4–8000.0 ng/g. The method gave good repeatability and extraction efficiency. Method LOQs ranged from 0.4–4.0 ng/g in the selected matrices. Good linearity was obtained over four orders of magnitude starting from LOQs. Isotopically labeled internal standards were used for quantitative calculations. The method was then successfully applied to the analysis of liver and brain tissues from SIUDS and SIDS victims coming from the above mentioned region. 相似文献
63.
Achille BarcoNikla Baricordi Simonetta Benetti Gisella BiondiniCarmela De Risi Gian Piero Pollini 《Tetrahedron》2003,59(42):8439-8444
Optically active carbacephams can be efficiently prepared generating the β-lactam ring on 2-substituted-piperidin-4-ones. These can, in turn, be prepared diastereoselectively through a Michael-Michael reaction sequence initiated by benzylamine on precursors derived by Wittig reaction between serinals and 4-[(4-methylphenyl)sulfonyl]-1-(triphenylphosphoranylidene)-2-butanone. 相似文献
64.
Bandini M Cozzi PG Giacomini M Melchiorre P Selva S Umani-Ronchi A 《The Journal of organic chemistry》2002,67(11):3700-3704
Low sensitivity toward traces of moisture and high tolerance of different functional groups make indium tribromide suitable for carrying out multistep synthetic sequences. In particular, we have realized a 1,4-conjugated addition of indoles/thiols to alpha,beta-unsaturated ketones mediated by a catalytic amount (10 mol %) of InBr(3) obtaining the desired beta-substituted ketones in good yields. The Lewis acidity of indium salts was not affected by coordinating and acid nucleophiles; therefore, the subsequent catalytic 1,2-addition of Me(3)SiCN to carbonyl compounds can be performed in one pot. With the optimized atom-efficient protocol, several polyfunctionalized alpha-silyloxy cyanohydrins were synthesized in good to excellent yields (up to 97%) and a notable level of simple 1,3-diastereoselection (up to 84:16) was recorded in the case of 2-cyclohexen-1-one 2c. 相似文献
65.
Pier Giovanni Baraldi Achille Barco Simonetta Benetti Mario Guarneri Stefano Manfredini Gian Piero Pollini Daniele Simoni 《Tetrahedron letters》1985,26(43):5319-5322
Geiparvarin 1 has been synthesized utilizing the 3,5-disubstituted isoxazole 8 as protected synthon for the 3(2h)furanone system, the desired α′-hydroxy-1,3-diketone precursor being eventually revealed by Mo(CO)6 promoted reductive cleavage. 相似文献
66.
Diego Savoia Emilio Tagliavini Claudio Trombini Achille Umani-Ronchi 《Journal of organometallic chemistry》1980,204(3):281-286
Highly dispersed potassium on alumina (K/Al2O3) acts as a metalating agent towards enolizable compounds and the intermediate organopotassium derivatives can be alkylated with primary alkyl bromides. The reaction conditions are dependent on the substrate. In particular, tetrahydrofuran is the solvent of choice for the metalation of nitriles and aldehydeN,N-dimethylhydrazones at ?60°C and of N-cyclohexyl ketimines at room temperature, whereas hexane must be used for ketones. 相似文献
67.
Gian Paolo Boldrini Diego Savoia Emilio Tagliavini Claudio Trombini Achille Umani-Ronchi 《Journal of organometallic chemistry》1985,280(3):307-312
The potassium—graphite route to active forms of metals has been extended to the preparation of titanium—graphite (Ti---Gr) and tin—graphite (Sn---Gr). The Ti---Gr is used to achieve the reductive coupling of ketones to give alkenes, and Sn---Gr is used in the preparation of diallyltin dibromide complexes which react with aldehydes to give homoallylic alcohols. 相似文献
68.
Achille De Battisti Vincenzo Faggiano Sergio Trasatti 《Journal of Electroanalytical Chemistry》1976,73(3):327-346
The adsorption of succinonitrile (SN) on a polarized Hg electrode has been studied from 0.25 M NaF aqueous solutions by means of both capacity and electrocapillary curves. Adsorption isotherms have been found to be strictly congruent with respect to both charge and potential. The charge of maximum adsorption is at ?4.6 μC cm?2 and ΔGads0, the free energy of adsorption at zero coverage, decreases more rapidly as the charge is made positive with respect to OmaxM than on the other side. The adsorption obeys a Frumkin isotherm with a=?1.87 corresponding to attraction and saturation concentration of 4.8×10?10 mol cm?2 corresponding to an area per molecule of about 34.5 Å2. Experimental results suggest that SN adsorbs flat on the surface but, unlike acetonitrile and propionitrile, the CN groups are slightly turned towards the solution. This is responsible for the absence of electronic interaction of the CN groups with the metal at positive charges, which is apparent with the other two nitriles. Implications of the particular structure of the adsorbed molecule on the other adsorption parameters are discussed in detail. 相似文献
69.
Bandini M Melloni A Umani-Ronchi A 《Angewandte Chemie (International ed. in English)》2004,43(5):550-556
After more than 125 years, the Friedel–Crafts alkylation is still one of the most studied and most utilized reactions in organic synthesis. What is the secret of this astonishing success? Perhaps the great versatility in scope and applicability continues to justify its crucial role in the synthesis of more and more complex molecules. However, it has taken more than a century for asymmetric catalytic versions of this reaction to be developed and subsequently extended to a range of aromatic compounds and alkylating agents. Herein we review recent developments in the design and use of catalytic and stereoselective strategies for the alkylation of aromatic systems and synthesis of a wide range of polyfunctionalized enantiomerically enriched compounds. 相似文献
70.
Kodama K Ushida N Mokhtarani A Paolone VS Volk JT Wilcox JO Yager PM Edelstein RM Freyberger AP Gibaut DB Lipton RJ Nichols WR Potter DM Russ JS Zhang Y Jang HI Kim JY Lim IT Pac MY Baller BR Stefanski RJ Nakazawa K Tasaka S Choi YS Chung KH Kim DC Park IG Song JS Yoon CS Chikawa M Abe T Fujii T Fujioka G Fujiwara K Fukushima H Hara T Takahashi Y Taruma K Tsuzuki Y Yokoyama C Chang SD Cheon BG Cho JH Kang JS Kim CO Kim KY Kim TY Lee JC Lee SB Lim GY Nam SW Shin TS Sim KS Woo JK Isokane Y 《Physical review letters》1991,66(14):1819-1822