Novel Polyhydroxysteroids from the Formosan Soft Coral Sarcophyton Glaucum

Two novel polyhydroxysteroids, (24S)‐24‐methylcholestane‐3β,5α,6β,25ξ;,26‐pentol 26‐n‐decanoate ( 1 ), (24S)‐24‐methylcholestane‐3β,5α,6β,25ξ;,26‐pentol 25,26‐diacetate ( 2 ), and three known sterols ( 3‐5 ), have been isolated from a Formosan soft coral Sarcophyton glaucum. The molecular structures of these compounds were determined by spectral methods. The cytotoxicity of these compounds toward various cancer cell lines has also been determined.     

Simultaneous determination of sweeteners and preservatives in preserved fruits by micellar electrokinetic capillary chromatography

A micellar electrokinetic capillary method for the simultaneous determination of the sweeteners dulcin, aspartame, saccharin, and acesulfame-K and the preservatives sorbic acid; benzoic acid; sodium dehydroacetate; and methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutyl-p-hydroxybenzoate in preserved fruits is developed. These additives are ion-paired and extracted using sonication followed by solid-phase extraction from the sample. Separation is achieved using a 57-cm fused-silica capillary with a buffer comprised of 0.05 M sodium deoxycholate, 0.02 M borate-phosphate buffer (pH 8.6), and 5% acetonitrile, and the wavelength for detection is 214 nm. The average recovery rate for all sweeteners and preservatives is approximately 90% with good reproducibility, and the detection limits range from 10 to 25 microg/g. Fifty preserved fruit samples are analyzed for the content of sweeteners and preservatives. The sweeteners found in 28 samples was aspartame (0.17-11.59 g/kg) or saccharin (0.09-5.64 g/kg). Benzoic acid (0.02-1.72 g/kg) and sorbic acid (0.27-1.15 g/kg) were found as preservatives in 29 samples.     

The Regioselectivity of (Dimethylvinylidene)carbene Directed by Aromatic Ring upon the Addition into Aryl Alkenes in the Presence of Other Olefins

Regioselective cycloaddition of (dimethylvinylidene)carbene (1) into aryl alkenes in the presence of other olefins is reported. The reaction is presumably controlled by the phenyl group, which forms an aromatic π-complex with the carbene C-3 orbital, followed by the selective addition of 1 to the closest phenyl-substituted double bond. Also, this selectivity is assumed to be attributed to delocalization of aromatic π electrons which increases the electron density of the conjugated carbon-carbon double bond, thus leading to the facile addition of vinylidenecarbene.     

New Norcembranoids from the Soft Coral Sinularia Lochmodes

Two new C‐4 norcembranoids sinulochmodins D ( 1 ) and E ( 2 ), along with three known norditerpenoids ( 3–5 ), have been isolated from the organic extract of a Taiwanese soft coral Sinularia lochmodes (Kolonko). The structures of 1 and 2 were determined on the basis of extensive spectroscopic analyses and by comparison of their spectral data with those of related metabolites.     

Drying induced phase transformation of mesoporous silica

Solvent evaporation upon drying the precipitate was found to be the key factor for the phase transformation of cubic mesoporous silica SBA-1 to hexagonal SBA-3 studied by in-situ X-ray diffraction and 29Si solid state NMR on the precipitates formed various crystallisation conditions.     

A hybrid fuzzy-optimization approach to customer grouping-based logistics distribution operations

This paper presents an integrated fuzzy-optimization customer grouping based logistics distribution methodology for quickly responding to a variety of customer demands. The proposed methodology involves three main mechanisms: (1) pre-route customer classification using fuzzy clustering techniques, (2) determination of customer group-based delivery service priority and (3) en-route goods delivery using multi-objective optimization programming methods. In the process of pre-route customer classification, the proposed method groups customers’ orders primarily based on the multiple attributes of customer demands, rather than by static geographic attributes, which are mainly considered in classical vehicle routing algorithms. Numerical studies including a real-world application are conducted to illustrate the applicability of the proposed method and its potential advantages over existing operational strategies. Using the proposed method, it is shown that the overall performance of a logistics distribution system can be improved by more than 20%, according to the numerical results from the case studied.     

Generic Algorithm for Generalized Fractional Programming

We propose a unified framework to study various versions of Dinkelbach-type algorithms for solving the generalized fractional programming problem. Classical algorithms used carefully selected iterate points and incorporated subtle convergence proofs. Our generic algorithm, however, is natural and simple. Moreover, the convergence analysis can be carried out through geometric observations and fundamental properties of convex functions. Consequently, the classical results are either refined or strengthened with new insights.     

Economic optimization of off-line inspection with rework consideration

This paper addresses issues relating to off-line inspection with rework consideration. We develop a mathematical model to determine the first unit inspected and the average number to be inspected in a batch, assuming the involvement of a quality-control department with a standard procedure. Numerical analyses are used to simulate the effect of changes in the various parameters on the optimal solution when the probability of a transition between states follows the discrete Weibull distribution.     

Ultrasound Promoted 1, 3-Dipolar Cycloaddition Reactions of Nitrile Oxides with α, β-Unsaturated Acetals

The 1,3-dipolar cycloaddition reactions of nitrile oxides and α,β-unsaturated 1,3-dioxolanes were effectively accelerated by ultrasound irradiation to give the A²-isoxazolines with yields and regioselectivities surpassing those of the corresponding thermal reactions.     

Oxidative modification of neurogranin by nitric oxide: an amperometric study

Neurogranin (Ng) is a neuron-specific protein kinase C (PKC) substrate, which contains four cysteine (Cys) residues. Recently, it has been shown that Ng is a redox-sensitive protein and is a likely target of nitric oxide (NO) and other oxidants [F.-S. Sheu, C.W. Mahoney, K. Seki, K.-P. Huang, Nitric oxide modification of rat brain neurogranin affects its phosphorylation by protein kinase C and affinity for calmodulin, J. Biol. Chem. 271 (1996) 22407-22413: J. Li, J.H. Pak, F.L. Huang, K.-P. Huang, N-methyl-D-aspartate induces neurogranin/RC3 oxidation in rat brain slices, J. Biol. Chem. 274 (1999) 1294-1300]. In this study, we directly examine the redox reactions between dissolved NO and Cys as well as between NO and bacterial expressed Ng in its reduced form, at concentrations approximate to the physiological levels in phosphate buffer solution (PBS) under aerobic conditions. The reaction kinetics are measured directly by our newly developed electrochemical sensor. Our sensor is based on the chemical modification of electrode with immobilized nanoparticles of transition metal palladium (Pd) which serves as catalytic centers for the electrochemical oxidation of thiol and NO selectively and quantitatively at different potentials. It detects Cys and Ng in a linear range from nano to micromolar concentration at + 450 mV, vs. a saturated calomel reference electrode (SCE), while the detection of NO at the sensor can be optimally achieved at + 700 mV (vs. SCE) with a linear current-to-concentration range of nM to microM. It thus provides a selective control to monitor two reactants independently. With this sensor as a detector, we found that (1) the oxidation of either Cys or Ng by NO is a fast reaction which reaches a near completion within 1-2 min at its physiological concentration; and (2) after the completion of reaction, NO is mostly, if not all, regenerated, an observation consistent with the reaction mechanism involving the formation of S-nitrosothiol as an intermediate. The reaction kinetics of both NO to Cys and NO to Ng implies that NO can achieve local action on cellular proteins in addition to its effect on targets located in neighboring cells via concentration-gradient-dependent diffusion.