Non-extinction of a Fleming-Viot particle model

We consider a branching particle model in which particles move inside a Euclidean domain according to the following rules. The particles move as independent Brownian motions until one of them hits the boundary. This particle is killed but another randomly chosen particle branches into two particles, to keep the population size constant. We prove that the particle population does not approach the boundary simultaneously in a finite time in some Lipschitz domains. This is used to prove a limit theorem for the empirical distribution of the particle family.     

Energy shift procedure for the inner potential in LEED crystallography

The accuracy of the assumption that LEED spectra for differing inner potentials can be found by shifting calculated spectra along the energy axis is studied. The spread in angle of refraction in typical conditions up to angle of incidence θ = 25° is shown to be small. The variation of θ with energy that minimizes the spread is found. Statistical analysis of data from three different surface structures shows the assumption to be adequate at least up to θ = 25°.     

Facile synthesis of 1-substituted c-norbenzomorphans

The olefinic-nitrile (4) undergoes a bromium ion-induced cyclisation to the tetrahydronaphthalene (5a) which on subsequent reduction and intramolecular nucleophilic displacement provides a facile route to 1-substituted C-norbenzomorphans.     

State assembles and the Bell-Wigner locality argument

The Bell-Wigner locality argument is shown to be a special case of the nonexistence of certain state assembles with preassigned densities when there are restrictions on the allowable states.     

ICP-AES法测定色漆可溶性金属含量

用ICP-AES法测定了色漆中的“可溶性”金属铬、镉、铅元素，考察了不同酸度对分析结果的影响，优化了测试条件。进行了回收率和精密度试验。并用原子吸收光谱国标方法进行对照，结果一致。     

Comparison of desorption/ionization on silicon (DIOS) time-of-flight and liquid chromatography/tandem mass spectrometry for assaying enzyme-inhibition reactions

Desorption/ionization on silicon with time-of-flight mass spectrometry (DIOS-TOFMS) was employed for rapid quantification of small molecules and the measurement of critical constants used in enzyme kinetics studies. The approach was used to determine the Michaelis constant (Km) for acetylcholine esterase and the 50% inhibition constant (IC50) for tacrine. The Km was determined from a Lineweaver-Burk plot to be 98 microM. The IC50 was determined by assaying acetylcholine esterase activity with a range of tacrine concentrations, and measuring the amount of choline produced at a fixed time point by either DIOS-TOFMS or by liquid chromatography tandem mass spectrometry (LC/MS/MS). DIOS-TOFMS indicated an IC50 of 32.0 nM while LC/MS/MS gave a value of 31.8 nM. The excellent correlation with the reported IC50 values, ranging from 30.0 to 50.0 nM, and equivalence with the LC/MS/MS results, confirms that the DIOS-TOFMS method can be used for rapid and specific quantification of enzyme-inhibition assays.