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1.
De novo synthesis of noncompetitive glycosidase inhibitors l-gulo-DNJ and l-talo-DNJ has been achieved in 9-10 steps starting from Garner’s aldehyde. Key to the success of this procedure was the construction of the 2,3-unsaturated piperidine 14, which syn dihydroxylation under Kishi’s and Donohoe’s conditions led to the desired iminosugars. 相似文献
2.
A straightforward procedure for the preparation of nucleoside analogue 1 and its regioisomer 2 containing a dihydro-1,4-dithiin as sugar moiety has been accomplished in four steps by our readily available heterocyclic system 5. Nucleobase insertion was carried out by direct addition of N4-acetylcytosine to sulfoxide derivatives via Pummerer-type glycosidation reaction. 相似文献
3.
Sara Paolella Mariangela Bencivenni Francesca Lambertini Barbara Prandi Andrea Faccini Cinzia Tonetti Claudia Vineis Stefano Sforza 《Journal of mass spectrometry : JMS》2013,48(8):919-926
In the present paper, a proteomic method for species determination in fibres has been developed. Keratin was extracted from yak, wool and cashmere fibres and digested by trypsin, providing peptide mixtures that were analyzed by liquid chromatography coupled with electrospray mass spectrometry (LC/ESI‐MS) in order to identify peptidic species‐specific markers able to differentiate the fibres. Several suitable peptide markers were identified and validated in different fibres of different origin and having undergone different technological treatments, showing 100% specificity and 100% selectivity. Most of the peptide markers were also identified by means of high‐resolution mass spectrometry, confirming the origin from species‐specific keratin sequences. Some peptides were also used for the quantification of the different species in mixed fibres by LC/ESI‐MS. Validation experiments and blind tests confirmed their ability to act as very specific quantitative and qualitative markers. The method here developed is a valid complement to the standard benchmark methods for fibre identification and quantification and will be very useful for assessing the authenticity of textile products. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
4.
In this paper we study the link between formal group of dimension one and integrable derivations of a ring of unequal characteristic.
Partially supported by M.U.R.S.T. (60%) and members of C.N.R.-G.N.S.A.G.A. 相似文献
5.
Gaetana Restuccia Cristodor Ionescu 《Rendiconti del Circolo Matematico di Palermo》1997,46(3):329-346
Letq be an integer ≥1, we study theq-torsion freeness of the symmetric powers of a module of projective dimension ≥2, by using the approximation complex of the module. 相似文献
6.
Gaetana Laricchia 《Hyperfine Interactions》1996,100(1):71-89
Recent progress in the study of atomic collisions using positronic projectiles is outlined and advances which might ensue from the production of more intense positron beams are indicated. Material in this paper was contained in a lecture delivered at the Workshop on Intense Positron Beams in Europe held at UCL on the 18th and 19th September, 1995. 相似文献
7.
Gaetana Restuccia 《Annali dell'Universita di Ferrara》1977,23(1):1-10
Riassunto Nel presente lavoro studiamo il problema seguente: seA è un anellom-adico eccellente, è pure eccellente l’anello (A, m) {X
1,…,X
n
} delle serie ristrette? I risultati che presentiamo sono relativi ad anelli baseA di char. 0, ma con quozienti di char.p>0; essi sono basati su tecniche che sfruttano fortemente i criteri jacobiani di regolarità. Perciò ci riferiamo sempre ad
anelli base ?di tipo analitico? (nel senso di [5], def. 1.1), cioè ad anelli muniti di un numero sufficiente di derivazioni,
tale da garantire la validità di criteri jacobiani. Proviamo che, seA è locale regolare di tipo analitico eA/pA è finito come modulo su (A/pA)
p
, allora (A, m) {X
1,…,X
n
} è eccellente; evitando così, rispetto a [10] (teorema 10), ogni condizione restrittiva sui corpi residui. Estendiamo inoltre
in modo naturale la definizione di anello di tipo analitico al caso non locale e troviamo condizioni necessarie e sufficienti
per la permanenza dell’analiticità nel passaggio alle serie ristrette. Proviamo infine che gli anelli analitici sono eccellenti
se lo sono modulop.
Lavoro eseguito nell’ambito dell’attività dei Gruppi di Ricerca Matematica del CNR (GNSAGA). 相似文献
Summary In the present paper we investigate the following problem: ifA is anm-adic excellent ring, is the restricted power series ring(A, m){X 1,…,X n } also excellent? Here we are able to produce some results when the basic ringsA are of char. 0, but with quotients of char.p>0. We need to use techniques which exploit strongly the jacobian criteria of regularity; hence we limit ourselves to the class of the basic rings ?of analytic type? (in the sense of [5], def. 1.1), i.e. rings with enough derivations to make jacobian criteria true. We prove that, ifA is a regular local ring of analytic type andA/pA is a finite module over (A/pA)p, then (A, m){X 1,…,X n } is excellent. With regard to [10], theorem 10, we can avoid every restrictive condition over the residue fields. Moreover we extend in a natural way the definition of a ring of analytic type in the case of a regular domain of char. 0 not necessarily local and we find necessary and sufficient conditions for the permanence of the analytic property in the passage to the restricted power series. At last we prove that the analytic rings are excellent if they are so modulop.
Lavoro eseguito nell’ambito dell’attività dei Gruppi di Ricerca Matematica del CNR (GNSAGA). 相似文献
8.
Paul L. Anderson James P. Hasak Alicia D. Kahle Nicholas A. Paolella Michael J. Shapiro 《Journal of heterocyclic chemistry》1981,18(6):1149-1152
Addition of pyridine-N-imine to a variety of acetylenic mono- (Scheme I) and di- (Scheme II) carboxylic ester dipolarophiles was carried out. Several of the 3-azapyrrocoline esters obtained were further converted into acids, amides and hydrazides as shown in Schemes I and II. 相似文献
9.
Gaetana Restuccia 《Rendiconti del Circolo Matematico di Palermo》1995,44(3):351-364
LetR be a regular ring containing a fieldk andE be a finitely generatedR-module of projective dimension two and with the second Betti number two or three. We prove sufficient conditions for the moduleE admitting an acyclic approximation complex. The argument implies that the symmetric algebra ofE is an integral domain. 相似文献
10.
Gaetana Restuccia 《Rendiconti del Circolo Matematico di Palermo》1983,32(3):289-306
Si considera il seguente problema posto da Grothendieck (E.G.A.): SeA è un anello eccellente edm un ideale diA, (A, m) ^=m-adico completamento diA è eccellente? Si mostra che la risposta è positiva nei seguenti casi:
- A=algebra di tipo finito su un DVR completo di caratteristicap>0;
- A=algebra di tipo finito su un DVRC contenente un corpok di caratteristicap>0 e finito suk [C p ] oppure tale che:
- per ogni sottocampok′ dik contenentek p tale che [k:k′]<∞, il modulo universale finito dei differenzialiD k′ (C) esiste;
- il corpo residuoK diC soddisfa rank KK ? K/k <∞
- C ha una Der-base.