Isolation of Some Antimicrobial Compounds of Red Wine by OPLC Flowing Eluent Wall Technique

The first results of the combination of BioArena and OPLC with flowing eluent wall technique (FEW) show an especially attractive solution of the detection of antimicrobial activity and compound isolation based on peak collection. Because of the different separation mechanisms applied for on-line FEW–OPLC isolation of red wine constituents and for further off-line OPLC investigation of fractions, the combined system yields high selectivity.     

maxLik: A package for maximum likelihood estimation in R

This paper describes the package maxLik for the statistical environment R. The package is essentially a unified wrapper interface to various optimization routines, offering easy access to likelihood-specific features like standard errors or information matrix equality (BHHH method). More advanced features of the optimization algorithms, such as forcing the value of a particular parameter to be fixed, are also supported.     

On a theorem of Shchepin and Repovš concerning the smoothness of compacta

We show that a theorem of Shchepin and Repovš concerning the smoothness of compacta follows from the theory of semicontinuous relations.     

The Mixed Problem for the Laplacian in Lipschitz Domains

We consider the mixed boundary value problem, or Zaremba’s problem, for the Laplacian in a bounded Lipschitz domain Ω in R ⁿ , n?≥?2. We decompose the boundary $ \partial \Omega= D\cup N$ with D and N disjoint. The boundary between D and N is assumed to be a Lipschitz surface in $\partial \Omega$ . We find an exponent q ₀?>?1 so that for p between 1 and q ₀ we may solve the mixed problem for L ^p . Thus, if we specify Dirichlet data on D in the Sobolev space W ^1,p (D) and Neumann data on N in L ^p (N), the mixed problem with data f _D and f _N has a unique solution and the non-tangential maximal function of the gradient lies in $L^p( \partial \Omega)$ . We also obtain results for p?=?1 when the data comes from Hardy spaces.     

A Capped Optimal Stopping Problem for the Maximum Process

This paper concerns an optimal stopping problem driven by the running maximum of a spectrally negative Lévy process X. More precisely, we are interested in capped versions of the American lookback optimal stopping problem (Gapeev in J. Appl. Probab. 44:713–731, 2007; Guo and Shepp in J. Appl. Probab. 38:647–658, 2001; Pedersen in J. Appl. Probab. 37:972–983, 2000), which has its origins in mathematical finance, and provide semi-explicit solutions in terms of scale functions. The optimal stopping boundary is characterised by an ordinary first-order differential equation involving scale functions and, in particular, changes according to the path variation of X. Furthermore, we will link these capped problems to Peskir’s maximality principle (Peskir in Ann. Probab. 26:1614–1640, 1998).     

A very special nonexistence theorem for abelian difference sets

It is wellknown that the technique of character sums together with the tools of algebraic number theory is the adequate method for the study of difference sets in abelian groups, compare for instance Ott [5] or Turyn [6]. In this paper we use this method to prove a new non-existence theorem for certain difference sets in abelian groups of order rp^a rp^a , where r 1 2 r \neq 2 and p are distinct primes.     

Discrete storage processes and their Poisson flow and fluid flow approximations

Consider discrete storage processes that are modulated by environmental processes. Environmental processes cause interruptions in the input and/or output processes of the discrete storage processes. Due to the difficulties encountered in the exact analysis of such discrete storage systems, often Poisson flow and/or fluid flow models with the same modulating environmental processes are proposed as approximations for these systems. The analysis of Poisson flow and fluid flow models is much easier than that of the discrete storage processes. In this paper we give sufficient conditions under which the content of the discrete storage processes can be bounded by the Poisson flow and the fluid flow models. For example, we show that Poisson flow models and the fluid flow models developed by Kosten (and by Anick, Mitra and Sondhi) can be used to bound the performance of infinite (finite) source packetized voice/data communication systems. We also show that a Poisson flow model and the fluid flow model developed by Mitra can be used to bound the buffer content of a two stage automatic transfer line. The potential use of the bounding techniques presented in this paper, of course, transcends well beyond these examples.Supported in part by NSF grant DMS-9308149.     

Fluorescence properties and antiproliferative effects of mono-, bis-, and tris- thiophenylnaphthalimides: results of a comparative pilot study

A series of mono-, bis- and trisnaphthalimides with different substituents on the naphthalimide ring system was prepared. For compounds containing a thiophenyl substituent fluorescence spectroscopic measurements were performed and unexpectedly showed an increase in fluorescence emission for the bis- and trisnaphthalimide derivatives in phosphate buffered saline. Additional fluorescence microscopic experiments indicated an efficient cellular uptake of the thiophenyl substituted compound 1c into cultured tumor cells. Experiments on the inhibition of tumor cell proliferation were performed in MCF-7 breast adenocarcinoma and HT-29 colon carcinoma cells and confirmed derivatives containing a nitro substituent as the most active compounds. Compound 1c demonstrated potential as photoinducable antitumor agent.     

Die Grenzen der Titrationsanalyse

Ohne Zusammenfassung