Activity-guided isolation of saponins from Kalopanax pictus with anti-inflammatory activity

By bioassay-guided separation, a known saponin, kalopanaxsaponin A (1) and a new saponin, pictoside A (2) were isolated from the stem bark of Kalopanax pictus as anti-inflammatory components when evaluated by vascular permeability test. Another novel saponin, pictoside B (3) was also isolated but was inactive in the test system used. The structures of pictosides A and B were elucidated as caulophyllogenin 3-O-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside (2) and pictogenin (3beta,6beta,16alpha,23-tetrahydroxyolean-12-ene-28-oic acid) 3-O-alpha-L-arabinopyranoside (3), respectively, by spectral analysis and by chemical degradation. Kalopanaxsaponin A and pictoside A showed significant anti-inflammatory activity at the oral doses of 50 mg/kg.     

Microcalorimetric determination of metal cations

Summary Silver and lead, respectively, are determined in a microcalorimeter by measuring the effect of the cation concentration upon an enzyme catalyzed reaction. The reduction in heat of the glucose oxidase catalyzed reaction in presence of Ag⁺ and Pb²⁺ is confirmed.

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Zusammenfassung Silber bzw. Blei kann man mit einem Mikrokalorimeter bestimmen, indem die Wirkung der Konzentration des Kations auf eine enzymatische Reaktion gemessen wird. Die Herabsetzung der Wärmetönung der durch Glukoseoxydase katalysierten Reaktion in Gegenwart von Ag⁺ bzw. Pb²⁺ wurde bestätigt.

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This work was supported by USPHS Grant CA 08023.     

An improved nearly-orthogonal structured mesh generation system with smoothness control functions

This paper presents an improved nearly-orthogonal structured mesh generation system with a set of smoothness control functions, which were derived based on the ratio between the Jacobian of the transformation matrix and the Jacobian of the metric tensor. The proposed smoothness control functions are capable of relaxing the local strong orthogonal conditions so that nearly orthogonal but smooth mesh can be achieved. Examples and applications are also investigated in this paper to demonstrate the effects of the proposed mesh generation system.     

Nonparametric estimation of the anisotropic probability density of mixed variables

The problem of nonparametric estimation of the joint probability density of a vector of continuous and ordinal/nominal categorical random variables with bounded support is considered. There are numerous publications devoted to the cases of either continuous or categorical variables, and the curse of dimensionality and strong regularity assumptions are the two familiar issues in the literature. Mixed variables occur in practically all applications of the statistical science and, nonetheless, the literature devoted to the joint density estimation is practically next to none. This paper develops the theory of estimation of the density of mixed variables which is on par with results known for simpler settings. Specifically, a data-driven estimator is developed that adapts to unknown anisotropic smoothness of the joint density and, whenever the density depends on a smaller number of variables, performs a dimension reduction that implies the corresponding optimal rate of the mean integrated squared error (MISE) convergence. The results hold without traditional, in the density estimation literature, minimal regularity assumptions like differentiability or continuity of the density. The procedure of estimation is based on mimicking an oracle-estimator that knows the underlying density, and the main theoretical result is the oracle inequality which relates the MISEs of the estimator and the oracle-estimator. The proof is based on a new exponential inequality for Sobolev statistics which is of interest on its own merits.     

Stabilization and tracking control for a class of nonlinear systems

This paper discusses stabilization and tracking control using linear matrix inequalities for a class of systems with Lipschitz nonlinearities. A nonlinear state feedback stabilization control is proposed for systems containing a more general case of Lipschitz nonlinearity. The main objective of the present study is to provide, for multi-input multi-output nonlinear systems, a tracking control approach based on nonlinear state feedback, which guarantees global asymptotic output and state tracking with zero tracking error in the steady state. Further, the tracking control is formulated for optimal disturbance rejection, using $L_2$ gain reduction based performance criteria. The proposed methodologies are illustrated herein using two simulation examples of chaotic and unstable dynamical systems.     

Adjoints of composition operators on Hardy spaces of the half-plane

Building on techniques used in the case of the disc, we use a variety of methods to develop formulae for the adjoints of composition operators on Hardy spaces of the upper half-plane. In doing so, we prove a slight extension of a known necessary condition for the boundedness of such operators, and use it to provide a complete classification of the bounded composition operators with rational symbol. We then consider some specific examples, comparing our formulae with each other, and with other easily deduced formulae for simple cases.     

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.     

A space-indexed formulation of packing boxes into a larger box

Current integer programming solvers fail to decide whether 12 unit cubes can be packed into a 1×1×11 box within an hour using the natural relaxation of Chen/Padberg. We present an alternative relaxation of the problem of packing boxes into a larger box, which makes it possible to solve much larger instances.     

Splash suppression during wafer wet cleaning through drop penetration across metal meshes and porous fiber mats

Journal of Visualization - Semiconducting silicon wafers were subjected to centrifugal wet cleaning to remove micro-contaminants. The circular wafers were rotated while a cleaning liquid was...