Four New Briarane Diterpenoids from the Gorgonian Coral Junceella fragilis

Chemical investigation of the gorgonian coral Junceella fragilis, collected by scuba diving in Taiwan, resulted in the isolation of four new briarane‐type diterpenoids, frajunolides A–D ( 1 – 4 ), along with three known briaranes. Their structures were elucidated on the basis of spectroscopic studies, especially 1‐ and 2D‐NMR as well as HR‐MS experiments. The inhibitory effect of all isolated metabolites towards superoxide‐anion generation and elastase release by human neutrophils in response to formylmethionyl‐leucyl‐phenylalanine/dihydrocytochalasin B (FMLP/CB) was evaluated.     

Structural Studies and Anticancer Activity of a Novel Class of β‐Peptides

Functionalized oligomeric organic compounds with well‐defined β‐proline scaffold have been synthesized by a cycloadditive oligomerization approach in racemic and enantiopure forms. The structure of the novel β‐peptides was investigated by NMR spectroscopic and X‐ray methods determining the conformational shapes of the β‐proline oligomers in solution and solid states. The main structural elements subject to conformational switches are β‐peptide bonds between 5‐arylpyrrolidine‐2‐carboxylic acid units existing in Z/E configurations. The whole library of short β‐peptides and intermediate acrylamides has been tested on antiproliferative activity towards the hormone‐refractory prostate cancer cell line PC‐3 revealing several oligomeric compounds with low micromolar and submicromolar activities. Bromine‐substituted dimeric and trimeric acrylamides induced caspase‐dependent apoptosis of PC‐3 cells through cell‐cycle arrest and mitochondrial damage.     

A Markov Chain Model for Medical Record Analysis

This paper presents a Markov chain model for the analysis of a centralized medical record system in a large general hospital. The model is used to describe the dynamic behaviour of the age of records associated with patients' visits to a hospital and provides a method for the long-term planning of the medical record storage facilities.     

Two new cytotoxic clerodane diterpenoids from Casearia membranacea

In addition to casearlucin A (3), two new clerodane diterpenes, caseamembrols A (1) and B (2) have been isolated from the leaves and twigs of Casearia membranacea by bioassay-guided fractionation. The structures of the new compounds were established on the basis of extensive 1D- and 2D-NMR spectroscopic analysis. Compounds 1-3 exhibited significant cytotoxicity against human prostate (PC-3) cancer cells.     

Two new sesquiterpene lactones from Ixeris chinensis

Phytochemical investigation of Ixeris chinensis NAKAI (Asteraceae) has resulted in the isolation of a new guaianolide-type sesquiterpene lactone, ixerochinolide (1) as well as the related glucoside, ixerochinoside (2). In addition, the known guaianolides, 8beta-hydroxy-3-oxo-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8beta-hydroxydehydrozaluzanin), 8beta,15-dihydroxy-2-oxo-guaia-1(10),3,11(13)-trien-5alpha,6beta,7alphaH-12,6-olide (lactucin), 3beta,8alpha,10alpha-trihydroxy-guaia-4(15),11(13)-dien-1alpha,5alpha,6beta,7alphaH-12,6-olide (10alpha-hydroxy-10,14-dihydro-desacylcynaropicrin) and 3beta-D-glucopyranosyloxy-8beta-(p-hydroxyphenylacetyloxy)-guaia-4(15),10(14),11(13)-trien-1alpha,5alpha,6beta,7alphaH-12,6-olide (8-epicrepioside) were identified. The structures were determined on the basis of spectral analyses, especially 1- and 2D NMR. Compound 1 exhibited significant cytotoxicity against human PC-3 tumor cells.     

Ligand sorption and chromatographic separation of metals with XAD-2 resin

Summary A macroreticular adsorbent (crosslinked copolymer of styrene and divinylbenzene) is used as the solid support. Ligands immobilized to the resin via physical forces selectively form complexes with metal ions in the solution, thus achieving separation or preconcentration. The compounds studied are sodium tetraphenylboron, 1,10-phenanthroline, 8,8(ethylenediimino)-diquinoline, 8-hydroxyquinoline and 5-chlorobenzotriazole. Since these agents possess properties of acids and bases, the pH of solution exerts great influence on the adsorption of ligands on the resin. pH-dependent studies on the distribution coefficient shows that, when conditions favor the existence of neutral species, the adsorption reaches maximum.

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Zusammenfassung Ein grobmaschiges Adsorptionsmittel (Copolymerisat aus Styrol und Divinylbenzol) wurde als feste Trägersubstanz verwendet. Daran durch physikalische Kräfte gebundene Liganden bilden selektiv Komplexe mit Metallionen in der Lösung und ermöglichen so deren Trennung oder Anreicherung. Als derartige Verbindungen wurden Bortetraphenylnatrium, 1,10-Phenanthrolin, 8,8-(Äthylendiimino)-dichinolin, 8-Hydroxychinolin und 5-Chlorbenzotriazol untersucht. Da es sich hierbei um Zwitterionenbildner handelt, hat das pH der Lösung großen Einfluß auf die Adsorption von Liganden an das Harz. Die Untersuchung der pH-Abhängigkeit des Verteilungskoeffizienten zeigt, daß die Adsorption ihr Maximum erreicht, wenn die Lösungsbedingungen die Bildung neutraler Formen begünstigen.

     

Synthesis and anti-cancer activity of a glycosyl library of \varvec{N}-acetylglucosamine-bearing oleanolic acid

N-Acetylglucosamine-bearing triterpenoid saponins (GNTS) were reported to be a unique type of saponins with potent anti-tumor activity. In order to study the structure–activity relationship of GNTS, 24 oleanolic acid saponins with ( $1 \rightarrow 3$ )-linked, ( $1\rightarrow 4$ )-linked, ( $1\rightarrow 6$ )-linked $N$ -acetylglucosamine oligosaccharide residues were synthesized in a combinatorial and concise method. The cytotoxicity of these compounds toward the leukemia cell line HL-60 and the colorectal cancer cell line HT-29 could not be improved. Half maximal inhibition below $10\,\upmu \hbox {M}$ was achieved in one single case. The study revealed that the activity decreased following the order of $3^{\prime }>4^{\prime }>6^{\prime }$ glycosyl modifications. GNTS that incorporated (d/l)-xylose and l-arabinose at positions $3^{\prime }$ and $4^{\prime }$ were more potent than those bearing other sugars.     

Organic‐Stabilizer‐Free Polyol Synthesis of Silver Nanowires for Electrode Applications

The polyol reduction of a Ag precursor in the presence of an organic stabilizer, such as poly(vinylpyrrolidone), is a widely used method for the production of Ag nanowires (NWs). However, organic capping molecules introduce insulating layers around each NW. Herein we demonstrate that Ag NWs can be produced in high yield without any organic stabilizers simply by introducing trace amounts of NaCl and Fe(NO₃)₃ during low‐temperature polyol synthesis. The heterogeneous nucleation and growth of Ag NWs on initially formed AgCl particles, combined with oxidative etching of unwanted Ag nanoparticles, resulted in the selective formation of long NWs with an average length of about 40 μm in the absence of a capping or stabilizing effect provided by surface‐adsorbing molecules. These organic‐stabilizer‐free Ag NWs were directly used for the fabrication of high‐performance transparent or stretchable electrodes without a complicated process for the removal of capping molecules from the NW surface.     

A Novel Secobetulinic Acid 3,4‐Lactone from Viburnum aboricolum

Bio‐assay‐guided fractionation of the CHCl₃‐soluble extract from the leaves of Viburnum aboricolum led to the isolation of a novel secobetulinic acid 3,4‐lactone, viburolide (=(6β)‐4,6‐dihydroxy‐3,4‐secolup‐20(29)‐ene‐3,28‐dioic acid 3,4‐lactone; 1 ). This is the first lupane‐type compound possessing such a lactone skeleton from natural products. Its structure was elucidated by spectral analysis and comparison with 6‐dehydroxy‐20,29‐dihydroviburolide ( 6 ) prepared from benzyl betulinate ( 2 ). Compound 6 was found to inhibit androgen‐independent human prostate cancer cells (PC‐3) with an IC₅₀ of 12.3 μM .     

A new clustering approach using data envelopment analysis

In this paper, we present a new clustering method that involves data envelopment analysis (DEA). The proposed DEA-based clustering approach employs the piecewise production functions derived from the DEA method to cluster the data with input and output items. Thus, each evaluated decision-making unit (DMU) not only knows the cluster that it belongs to, but also checks the production function type that it confronts. It is important for managerial decision-making where decision-makers are interested in knowing the changes required in combining input resources so it can be classified into a desired cluster/class. In particular, we examine the fundamental CCR model to set up the DEA clustering approach. While this approach has been carried for the CCR model, the proposed approach can be easily extended to other DEA models without loss of generality. Two examples are given to explain the use and effectiveness of the proposed DEA-based clustering method.