Search for D0-D(-)0 mixing and a measurement of the doubly Cabibbo-suppressed decay rate in D0-->Kpi decays

We present results of a search for D0-D(-)0 mixing and a measurement of R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays, using D0-->K+pi- decays from 57.1 fb(-1) of data collected near sqrt[s]=10.6 GeV with the BABAR detector at the PEP-II collider. At the 95% confidence level, allowing for CP violation, we find the mixing parameters x('2)<0.0022 and -0.056相似文献   

Beta-lactams or gamma-lactams by 4-exo-trig or 5-endo-trig anionic cyclisation of lithiated acrylamide derivatives

Substituted acrylamide derivatives of benzylamine are lithiated alpha to nitrogen by LDA. The benzyllithium thus formed undergoes either 5-endo-trig anionic cyclisation, formally by intramolecular conjugate addition to the acrylamide, to yield 5-membered lactams, or, if the acrylamide bears a beta-electron withdrawing group, 4-exo-trig cyclisation to a beta-lactam.     

Sequential reaction of p-toluidine with 2,3-dichloromaleic anhydride: Synthesis and molecular structure of 2-chloro-3-p-toluidino-N-p-tolylmaleimide

The reaction of equimolar amounts of p-toluidine with 2,3-dichloromaleic anhydride in refluxing toluene affords 2,3-dichloro-N-p-tolylmaleimide (1) and 2-chloro-3-p-toluidino-N-p-tolylmaleimide (2), as the major and minor products, respectively. While increasing the amount of p-toluidine relative to 2,3-dichloromaleic anhydride yields the latter compound as the major product, the replacement of the chloro group in 2-chloro-3-p-toluidino-N-p-tolylmaleimide by added p-toluidine was not observed in refluxing toluene. Both 1 and 2 were isolated by column chromatography and characterized in solution by IR and NMR spectroscopies. The solid-state structure of 2-chloro-3-p-toluidino-N-p-tolylmaleimide was solved by X-ray crystallography. Further, 2-Chloro-3-p-toluidino-N-p-tolylmaleimide crystallizes in the monoclinic space group C2/c, a = 33.191(8) Å, b = 4.037(1) Å, c = 24.876(6) Å, = 107.050(4)°, V = 3187(1) ų, Z = 8, and d _calc = 1.362 mg/m³; R = 0.0561, R _w = 0.1246 for 2087 reflections with I > 2 (I).     

Liquid chromatography-mass spectrometry in the study of the metabolism of drugs and other xenobiotics

The application of liquid chromatography-mass spectrometry (LC/MS) to the study of metabolism of drugs and other xenobiotics is reviewed. Original research papers covering the period from 1998 to early 2000 and concerning the use of LC/MS in the study of xenobiotic metabolism in humans and other mammalian species are reviewed. LC/MS interfaces, sample preparation steps, column types, mobile phases and additives, and the type of metabolites detected are summarized and discussed in an attempt to identify the current and future trends in the use of LC/MS for metabolism studies. Applications are listed according to the parent xenobiotic type and include substances used in therapeutics, drug candidates, compounds being evaluated in clinical trials, environmental pollutants, adulterants and naturally occurring substances.     

M-matrix asymptotics for Sturm–Liouville problems on graphs

We consider a system formulation for Sturm–Liouville operators with formally self-adjoint boundary conditions on a graph. An M-matrix associated with the boundary value problem is defined and related to the matrix Prüfer angle associated with the system boundary value problem, and consequently with the boundary value problem on the graph. Asymptotics for the M-matrix are obtained as the eigenparameter tends to negative infinity. We show that the boundary conditions may be recovered, up to a unitary equivalence, from the M-matrix and that the M-matrix is a Herglotz function. This is the first in a series of papers devoted to the reconstruction of the Sturm–Liouville problem on a graph from its M-matrix.     

To breathe or not to breathe—That is the question: An investigation of speech breathing kinematics in world class Shakespearean actors

Anteroposterior diameter changes of the rib cage and abdomen were recorded during respiratory and speaking activities in four adult subjects, three men and one woman, all of whom had extensive dramatic training and experience and were earning their livelihood as professional actors. Data were charted to solve for lung volume, and volume displacements of the rib cage and abdomen. The more vigorous and louder monologue performances by the professional actor subjects differed from other speaking and reading activities in the following parameters of lung volume, separate volumes, relative volume contributions, and the frequent use of respiratory phase transitions. Novice actor subjects' monologue performances are compared to the monologue performances of the professional actor subjects.