Carbon-13 NMR analysis of cyclobutane dimers from benzocycloalkenes

¹³C NMR Spectra for a series of 11 substituted cyclobutanes derived from photodimerization of benzocycloalkenes were recorded. Comparison of the carbon chemical shifts for the head-to-head and head-to-tail cis-syn-cis and cis-anti-cis isomers reveals shielding trends which should facilitate structural and stereochemical assignments for related compounds. The head-to-head isomers show a larger separation of cyclobutane carbon resonances than the head-to-tail isomers. The cis-syn-cis isomers relative to the cis-anti-cis isomers exhibit distinctive upfield shifts of all carbon resonances, except those of aromatic carbons ortho to alkyl-substituted aromatic carbons.     

Abstract Riemann surfaces of integral domains and spectral spaces

Sunto La superficie astratta di Riemann di un dominio R, introdotta da Zariski, è uno spazio topologico X(R) il cui insieme sostegno consiste di tutti i sovranelli di valutazione di R. L'applicazione canonica suriettiva f_R: X(R) Spec(R), V centro di V su R, è un'applicazione chiusa, dunque Spec(R) è uno spazio-quoziente di X(R). Il teorema principale di questo lavoro è il seguente: X(R) è uno spazio spettrale, nel senso di M. Hochster, e f_R è un'applicazione spettrale. Inoltre, facendo uso della cosiddetta topologia costruttibile, viene dimostrato che se R è integralmente chiuso e Spec(R) è uno spazio noetheriano allora f_R è un'applicazione aperta se e soltanto se R è un going-down dominio.

---

---

Supported in part by the University of Tennessee Faculty Development Grant, by Dipartimento di Matematica dell'Università di Roma «La Sapienza» and by a NATO Collaborative research Grant N. 35/85.

---

Supported in part by a grant from the Research Council of the Graduate School of the University of Missouri, Columbia.

---

Work done under the auspices of GNSAGA of the Consiglio Nazionale delle Ricerche, partially supported by a NATO Grant N. 35/85.     

Conducive integral domains as pullbacks

This article presents a characterization of conducive (integral) domains as the pullbacks in certain types of Cartesian squares in the category of commutative rings. Such squares behave well with respect to (semi)normalization, thus permitting us to recover the recent characterization by Dobbs-Fedder of seminormal conducive domains. The conducive domains satisfying various finiteness conditions (Noetherian, Archimedean, accp) are characterized by identifying suitable restrictions on the data in the corresponding Cartesian squares. Various necessary or sufficient conditions are given for Mori conducive domains. Consequently, one has examples of several (accp non-Mori; Mori non-Noetherian) conducive domains.Work performed under the auspices of GNSAGA of Consiglio Nazionale delle Ricerche and Dipartimento di Matematica, Università di Roma La SapienzaSupported in part by grants from University of Tennessee Faculty Development Program and the Università di Roma La Sapienza     

Measurement of epidoxorubicin and its metabolites by high-performance liquid chromatography using an advanced automated sample processor.

A sensitive and rapid method for measuring epidoxorubicin and its six metabolites by high-performance liquid chromatography using an advanced automated sample processor is described. Plasma samples (1 ml) were extracted using C2 cassettes, and reversed-phase chromatography was performed with an Apex II ODS column. The isocratic mobile phase of acetonitrile-0.019 M NaH2PO4 (pH 4.0) had a flow-rate of 1 ml/min and the fluorescence detector an excitation wavelength of 480 nm with an emission at 580 nm. Linear calibration curves were obtained which were reproducible both within-day and day-to-day (coefficients of variation less than 10%). The extraction efficacy of epidoxorubicin was 88% and ranged from 51 to 88% for the metabolites. This method has been successfully applied to measure the plasma levels of these compounds in patients receiving epidoxorubicin over a wide dose range (12-120 mg/m2) and in patients with disturbed liver biochemistry.     

Pseudo-almost valuation domains are quasilocal going-down domains,but not conversely

Abstract  Ayman Badawi has recently introduced the PAVDs, a class of (commutative integral) domains which is found strictly between the class of APVDs (“almost pseudo valuation domains”) and that of the (necessarily quasilocal) domains having a linearly ordered prime spectrum. It is known that the latter class strictly contains the class of quasilocal going-down domains; it is proved that the class of quasilocal going-down domains strictly contains the class of PAVDs. Consequently, each seminormal PAVD is a divided domain. Moreover, for each n, 1 ≤ n ≤ ∞, an example is constructed of a divided domain (necessarily a quasilocal going-down domain) of Krull dimension n which is not a PAVD. Keywords Pseudo-almost valuation domain, Prime ideal, Going-down domain, Divided domain, Quasilocal, Valuation overring, Root extension, Seminormal, D+M construction, Krull dimension Mathematics Subject Classification (2000) Primary 13B24, 13G05, Secondary 13A15, 13F05     

First observation of the decay Ds+-->pn

Using e+e--->Ds*-Ds+ data collected near the peak Ds production energy, Ecm=4170 MeV, with the CLEO-c detector, we present the first observation of the decay Ds+-->pn. We measure a branching fraction B(Ds+-->pn)=(1.30+/-0.36(-0.16)+0.12)x10(-3). This is the first observation of a charmed meson decaying into a baryon-antibaryon final state.     

Absolute measurement of hadronic branching fractions of the Ds+ meson

The branching fractions of D(s)(+/-) meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 pb(-1) of e(+)e(-) collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D(s)(+/-) decays with a double tag technique. In particular we determine the branching fraction B(D(s)(+)-->K(-)K(+}pi(+))=(5.50+/-0.23+/-0.16)%, where the uncertainties are statistical and systematic, respectively. We also provide partial branching fractions for kinematic subsets of the K(-)K(+)pi(+) decay mode.     

Study of the decays D0-->pi{-}e{+}nu{e}, D{0}-->K{-}e{+}nu{e}, D{+}-->pi{0}e{+}nu{e}, and D{+}-->K0e{+}nu{e}

By using 1.8x10{6} DDpairs, we have measured B(D{0}-->pi{-}e{+}nu{e})=0.299(11)(9)%, B(D{+}-->pi{0}e{+}nu{e})=0.373(22)(13)%, B(D{0}-->K{-}e{+}nu{e})=3.56(3)(9)%, and B(D{+}-->K{0}e{+}nu{e})=8.53(13)(23)% and have studied the q;{2} dependence of the form factors. By combining our results with recent lattice calculations, we obtain |V{cd}|=0.217(9)(4)(23) and |V{cs}|=1.015(10)(11)(106).     

Precision measurement of the mass of the hc(1P1) state of charmonium

A precision measurement of the mass of the h_{c}(1P1) state of charmonium has been made using a sample of 24.5x10;{6} psi(2S) events produced in e;{+}e;{-} annihilation at the Cornell Electron Storage Ring (CESR). The reaction used was psi(2S)-->pi;{0}h_{c}, pi;{0}-->gammagamma, h_{c}-->gammaeta_{c}, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_{c} decays are reconstructed in 15 hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_{c})=3525.28+/-0.19(stat.)+/-0.12(syst.) MeV, and B(psi(2S)-->pi;{0}h_{c})xB(h_{c}-->gammaeta_{c})=(4.19+/-0.32+/-0.45)x10;{-4}. Using the ;{3}P_{J} centroid mass, DeltaM_{hf}(1P) identical withM(chi_{cJ})-M(h_{c})=+0.02+/-0.19+/-0.13 MeV.