Studies on the Formosan Soft Corals I-Cytotoxic Cembrane Diterpenes from Sarcophyton Trocheliophorum

Two cytotoxic cembranoid diterpenes, (+)-isosarcophytoxide (1) and ( + )-isosarcophine (2), were isolated from the soft coral Sarcophyton trocheliophorum by cytotoxicity-guided fractionation. These two compounds demonstrated potent cytotoxicity against P-388 and HL-60 cells.     

Amplification of small analytes in polymer solution by capillary electrophoresis

We report concentration methods for the analysis of small solutes by capillary electrophoresis in conjunction with laser-induced native fluorescence using a Nd:YAG laser. After injecting samples, poly(ethylene oxide) (PEO) in the anode reservoir entered a capillary filled with Tris-borate buffer. When migrating in PEO solution, the analytes slowed down and stacked at the interface between the sample zone and PEO solution. As a result, the limits of detection (LODs) down to 8 pM for 2-naphthalenesulfonic acid and 70 pM for L-tryptophan have been achieved when injecting at 30 cm height for 120 s and 230 s, respectively. Such low LODs are partially due to the effects of NaCl in the samples and PEO on the fluorescence characteristics of the analytes. In addition, the concentrations of NaCl and PEO have great impacts on the migration of the analytes and electroosmotic flow, thereby affecting resolution and speed. Without pretreatment, the determinations of five important markers in urine samples and two acids in a cerebrospinal fluid sample have been performed separately, with the relative standard deviations of the concentrations less than 3.6%. Furthermore, by applying a short plug of low-pH buffer after injection, the analysis of greater volumes of the urine sample has been carried out, resulting in detecting more peaks.     

Borromean rings and linkings

For links of 3 components, such as Borromean rings, which escape the detection of Gauss linking, we define and compute combinatorically and explicitly the higher linking. And as in perturbative quantum field theory, this higher linking is presented as a sum of Chern–Simons–Witten configuration space integrals.     

Capacity allocation,ordering, and pricing decisions in a supply chain with demand and supply uncertainties

This paper studies coordinated decisions in a decentralized supply chain that consists of one Original Equipment Manufacturer (OEM), one manufacturer, and one distributor, and possesses uncertainties at both demand and supply sides. These uncertainties emerge, respectively, from random demand the distributor faces and randomness of capacity with which the OEM processes the manufacturer’s outsourced quantity. Sharing supply and demand uncertainty information along the supply chain enables us to develop three models with different coordination efforts—the OEM and manufacturer coordination, the manufacturer and distributor coordination, and the OEM, manufacturer, and distributor coordination—and quantify the coordinated decisions in these three models. Our analysis of these coordination models suggests that coordinating with the OEM improves the manufacturer’s probability of meeting downstream demand and his expected profit, yet coordinating with the manufacturer is not necessarily beneficial to the OEM when downstream coordination is lacking.     

Synthesis of oligo(phenyleneethynylene)s containing central pyromellitdiimide or naphthalenediimide groups and bearing terminal isocyanide groups: molecular components for single-electron transistors

Oligo(phenyleneethynylene)s that are of variable length, contain a central arenediimide unit, either a pyromellitdiimide or a naphthalenediimide group, and are terminated by isocyanide groups have been prepared. The extended frameworks were assembled from appropriately functionalized arenediimide and areneformamide units whose lengths were adjusted by adding phenyleneethynylene units. Final transformation of the formamide groups into isocyanide groups gave the title compounds. Several isocyanide-terminated oligo(phenyleneethynylene)s without an arenediimide unit have also been prepared.     

Effects of centralization on expected profits in a multi-location newsboy problem

This paper develops a single-period, single-product inventory model with several individual sources of demand. It is a multi-location problem with an opportunity for centralization. Both decentralized and centralized inventory systems are also examined to extend the Ravindram, Phillips and Solberg (RPS) model to constitute a new inventory model. Two theorems that include the results of the RPS model are proved in the new inventory model.     

Studies on the conducting nanocomposite prepared by in situ polymerization of aniline monomers in a neat (aqueous) synthetic mica clay

The in situ polymerization of the anilinium‐intercalated synthetic mica clay can easily result in an intercalated polyaniline (PANI)/clay nanocomposite. The FT‐IR spectra demonstrated a significant shift for ν_{(C? N)} at 1292 cm^?1 of the templated polymerized and intercalated PANI molecules. A red shift of λ_max for PANI was found from UV–vis spectra. The intercalated PANI also expanded the clay basal spacing seen from WAXD patterns. The degradation rate and temperature of the nanocomposites were found to alleviate and increase compared to neat PANI, respectively. The microscopic examinations including TEM, SEM, and AFM pictures of the nanocomposite demonstrated an entirely different and more compatible morphology. Conductivity of nanocomposite gradually increased with PANI and apparent increase was found when intercalated PANI content reached 40.6 wt %, the possible percolation threshold. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1800–1809, 2008     

Ordering and pricing decisions in a two-echelon supply chain with asymmetric demand information

This article examines coordinated decisions in a decentralized supply chain that consists of one supplier and one retailer, and faces random demand of a single product with a short life cycle. We consider a setting where the retailer has accurate demand information while the supplier does not. Such a problem with asymmetric demand information can be viewed as an extension of the newsboy problem in which both the supplier and the retailer possess the same demand information. Combining the mechanism of sharing demand information and that of quantity discount and return policy enables us to develop three coordinated models in contrast with the basic and uncoordinated model. We are able to show the ordinal relationship among the retailer’s optimal order quantities in these four models under a general form of random demand, and compare the supply chain profits and conduct sensitivity analysis analytically in four models under uniform random demand. We also provide numerical results under normal random demand that bear a resemblance to those under uniform random demand.     

Protein Folding and β‐Sheet Proteins

The aim of this comprehensive review is to critically evaluate the progress in research in the area of protein folding. In the first section, we discuss the various models proposed to explain the protein folding paradox. In the succeeding section of the review, a detailed account of the developments in our understanding of the folding path ways of β‐sheet proteins is provided.