Stereospecific vinyl substitutions occurring by free radical addition-elimination

The free radical chain reaction between cyclohexyl-HgCl and ($\text{E}$) or ($\text{Z}$) MeO₂CCH=CHSnBu₃, MeO₂CCH=CHI, or ClCH=CHHgCl forms MeO₂CCH=CHC₆H₁₁ or ClCH=CHC₆H₁₁ in a stereospecific manner with retention of stereochemistry.     

Corchorusides A and B, new flavonol glycosides as α-glucosidase inhibitors from the leaves of Corchorus olitorius

Corchorus olitorius, a highly fibrous vegetable commonly known as moroheiya, has long been recognized for its hypoglycemic activity. Bioassay-guided fractionation of the leaf extract led to the isolation of two new flavonol glycosides named corchorusides A and B, in addition to a major component, capsugenin-25,30-O-β-diglucopyranoside. Corchoruside A comprises a kaempferol moiety connected with caffeic acid, glucose, and a rare methyl glucuronate (MeGlcA). The occurrence of a caffeoyl moiety in corchoruside A enhanced significantly its inhibitory effect toward α-glucosidase compared to that in corchoruside B.     

Two dimension photonic crystal Y-branch beam splitter with variation of splitting ratio based on hybrid defect controlled

This article represents a new Y-branch hybrid design of 2D photonic crystal with defect control. The structure is made of hexagonal arrays of InP nano-rods surrounded by air. This system is comprised of a modified add/change to a polymethylmethacrylate (PMMA) rod, which can be applied to the beam splitter selection device. The optical properties and radial of PMMA defect rods have been transfigured. By selecting an appropriate temperature, a change of refractive index and expanded radius are occurred. The obtained results have shown that the selected optical amplitude in a hybrid semiconductor-polymer Y-branch can be separated to 50–50, 60–40 and 67–33 % at wavelength 1.557 µm. Both of the photonic band gap and transmission spectra are calculated by using 2D finite different time domain (FDTD) method via OptiFDTD software. Such a device can be useful for photonic crystal switching devices in the integrated optical circuit.     

Azocalix[4]arene Strapped Calix[4]pyrrole: A Confirmable Fluoride Sensor

A new chromogenic fluoride sensor based on 1,3-di-p-nitrophenylazocalix[4]arene-calix[4]pyrrole (1) was designed and synthesized. The color of the solution of probe 1 changed upon the addition of any F(-), CH(3)CO(2)(-), PhCO(2)(-), and H(2)PO(4)(-) ions. However, from these ions the highly specific sensing of F(-) is achieved by the addition of Ca(2+) which leads to a color change from light sky blue (of 1·F(-)) back to the original light orange color of 1.     

Shinsonefuran, a cytotoxic furanosesterterpene with a novel carbon skeleton, from the deep-sea sponge Stoeba extensa

Shinsonefuran, a cytotoxic sesterterpene with a novel carbon skeleton, was isolated from the deep-sea sponge Stoeba extensa. The gross structure and relative stereochemistry of shinsonefuran were determined by spectral and chemical methods. In addition, relative stereochemistry of halisulfate 7, previously reported from a marine sponge Coscinoderma sp., was revised. Shinsonefuran exhibited cytotoxicity against HeLa cells with an IC₅₀ value of 16 μg/mL.     

Breakdown voltage investigation of fusion SiO2 optical coupler switch using Pockel effect model

This paper describes a new model for the breakdown voltage of SiO₂ fiber coupler using the Pockel effect and empirical equation. The model is evaluated by using the coupling coefficient and the changes in the refractive index. We found that the breakdown voltage is in the order of 10² V correspond to coupling coefficient by the order of mm^?1. Increasing the value of coupling coefficient between the electrodes leads to a reduction in the breakdown voltage.     

Feroniellins A-C, novel cytotoxic furanocoumarins with highly oxygenated C10 moieties from Feroniella lucida

Three new furanocoumarins, named feroniellins A (1), B (2), and C (3), were isolated from the roots of Feroniella lucida. Compounds 1-3 are novel structures having an oxolane, oxane, and oxepane moiety. Their overall structures and configurations were determined by spectral and chemical methods. The cytotoxicities of 1-3 were evaluated against human KB and HeLa carcinoma cells.     

Dispersion stability of a ceramic glaze achieved through ionic surfactant adsorption

The adsorption of cetylpyridinium chloride (CPC) and sodium dodecylbenzenesulfonate (SDBS) onto a ceramic glaze mixture composed of limestone, feldspar, quartz, and kaolin has been investigated. Both adsorption isotherms and the average particle zeta potential have been studied in order to understand the suspension stability as a function of pH, ionic strength, and surfactant concentration. The adsorption of small amounts of cationic CPC onto the primarily negatively charged surfaces of the particles at pH 7 and 9 results in strong attraction and flocculation due to hydrophobic interactions. At higher surfactant concentrations a zeta potential of more than +60 mV results from the bilayered adsorbed surfactant, providing stability at salt concentrations < or = 0.01 M. At 0.1 M salt poor stability results despite substantial zeta potential values. Three mechanisms for SDBS adsorption have been identified. When anionic SDBS monomers either adsorb by electrostatic interactions with the few positive surface sites at high pH or adsorb onto like charged negative surface sites due to dispersion or hydrophobic interactions, the magnitude of the negative zeta potential increases slightly. At pH 9 this increase is enough to promote stability with an average zeta potential of more than -55 mV, whereas at pH 7 the zeta potential is lower at about -45 mV. The stability of suspensions at pH 7 is additionally due to steric repulsion caused by the adsorption of thick layers of neutrally charged Ca(DBS)2 complexes created when the surfactant interacts with dissolved calcium ions from the calcium carbonate component.     

Anhydrocochlioquinone A, a new antitumor compound from Bipolaris oryzae

In the search for antitumor compounds from Bipolaris oryzae, the coexistence of ophiobolins and cochlioquinones is reported for the first time. Of the compounds isolated, anhydrocochlioquinone A (7) was identified as a new antitumor agent. The structure of 7 was fully characterized by spectroscopic data, including COSY, HSQC, HMBC, and NOESY. The cytotoxicity of isolated compounds against HeLa and KB cells is also described.