Lobocrasol (1), possessing an unprecedented diterpenoid skeleton, was isolated from the soft coral Lobophytum crassum. The structure of lobocrasol was established by extensive analysis of spectroscopic data.

A comparative analysis of phenanthrenequinone-doped poly(methyl methacrylate) materials fabricated at California Institute of Technology and National Chiao Tung University is performed in order to understand the dierences exhibited in their recording and baking dynamics. Ó 2001 Published by Elsevier Science B.V.Keywords: Holography; Photopolymer material; PQ-PMMA; Grating dynamics; Temperature eect Phenanthrenequinone-(PQ-) doped poly(methyl methacrylate) (PMMA) [1,2] has been used as a recording material in optical memories and other holographic systems [3±6]. This material consists of a polymeric basis doped with chromophores, the PQ molecules. This material is lightweight and durable, and does not suer from shrinkage. High optical quality samples of dierent shapes and thicknesses can be obtained. These properties make it an excellent candidate for holographic memory modules. In this paper, we compare the PQ±PMMA samples that we use at California Institute of Technology (Caltech) with those fabricated at National Chiao Tung University (NCTU) and try to understand the dierences in behavior they exhibit.Sample preparation consists of dissolving PQ molecules ( 6 0.7%) in liquid methyl methacrylate (MMA) together with azo-bis-isobutyrolnitrile, a polymerization thermal initiator. This solution is poured into molds and allowed to polymerize in a pressure chamber. The preparation process followed at Caltech diers from the one followed at NCTU in the temperature at which the pressure chamber is set during polymerization. For the Caltech material, the temperature of the chamber is set to 80°C. On the other hand, at NCTU the polymerization process is split into two steps [4,7]. First, the solution is let to rest at room temperature for approximately 120 h until the solution turns homogeneously viscid. At this point, the

Chemical investigation of the Dongsha Atoll soft coral Lobophytum crassum has afforded four new cembranoids, crassumols A–C (1–3) and 13-acetoxysarcophytoxide (4). The structures of these isolated compounds were elucidated by extensive NMR and HRESIMS experiments. The cytotoxicity and anti-HCMV (Human cytomegalovirus) activities of 1–4 were evaluated in vitro. Compound 4 exhibited cytotoxicity against A-549 (human lung carcinoma) cell line with an ED50 of 3.6 μg/mL.

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