Ordered macroporous silica, a silica gel microhoneycomb (SMH), has been prepared through a method which uses micrometer-sized ice crystals as a template. Template ice crystals, which have a continuous rod shape, a polygonal cross section, and ordered diameters, were grown inside precursor silica hydrogels under a condition where the pseudo-steady-state growth of them continues. Besides their ordered macroporosity, micro-/mesopores develop inside the honeycomb walls through the freeze-drying of SMHs soaked in tert-butyl alcohol. SMHs have straight and polygonal macroporous voids, which are created and retained through the formation and removal of the ice crystals. Micromorphology including macropore size and wall thickness, micro-/mesoporosity inside the honeycomb walls, and thermal stability of SMHs were investigated in detail through scanning electron microscopy observation, nitrogen adsorptiondesorption measurements, and thermogravimetric analysis. It was found that the macropore size of the SMHs can be controlled by changing the immersion rate into a cold bath and the freezing temperature without changing the micro-/mesoporosity of their honeycomb walls. It was also found that the thickness of the honeycomb walls was affected by the SiO 2 concentration and the macropore size. On the other hand, the porosity of the honeycomb walls could be controlled to be microporous as well as mesoporous by hydrothermal treatment of as-prepared SMHs in basic aqueous solutions. Moreover, it was found that SMHs with developed mesopores showed a higher stability against heat treatment.

The aim of this study was to evaluate the effect of surface roughness on the initial attachment of mouse osteoblast-like cells on ceria stabilized zirconia/alumina nanocomposite (NANOZR) and yttria-stabilized zirconia (3Y-TZP) in comparison to those on pure titanium (Ti) and alumina oxide (AO). Specimens with smooth and rough surfaces were prepared by grinding with diamond paper or by sandblasting, respectively. For four substrates examined, the number of attached cells on the rough surface specimens was significantly higher than that on the smooth surface specimens (p < 0.05). Integrin α5 and β1 expression had a greater increase in rough surface specimens than in smooth surface specimens. Actin cytoskeleton organization was, however, similar for both smooth and rough surface specimens. NANOZR and 3Y-TZP produced good cell attachment, similar to Ti and AO. The overall results demonstrated that NANOZR and 3Y-TZP with rough surface could provide good initial cell responses, adequate for future implant usage.

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Extinctions within major pelagic groups (e.g., radiolarians and conodonts) occurred in a stepwise fashion during the last 15 Myr of the Triassic. Although a marked decline in the diversity of pelagic faunas began at the end of the middle Norian, the cause of the middle Norian extinction is uncertain. Here we show a possible link between the end-middle Norian radiolarian extinction and a bolide impact. Two palaeoenvironmental events occurred during the initial phase of the radiolarian extinction interval: (1) a post-impact shutdown of primary and biogenic silica production within a time span of 104–105 yr, and (2) a sustained reduction in the sinking flux of radiolarian silica for ~0.3 Myr after the impact. The catastrophic collapse of the pelagic ecosystem at this time was probably the dominant factor responsible for the end-middle Norian conodont extinction.

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The Zoanthus alkaloids, to which zoanthamines and (À)-norzoanthamine (1) belong, have attracted a great deal of attention in the synthetic community owing to their significant biological activity [1] as well as their unique and complex heptacyclic structure. Although several groups have attempted the synthesis of these alkaloids, [2][3][4] only the Miyashita research group has accomplished a total synthesis. [4] The most challenging steps towards the total synthesis of (À)-norzoanthamine are the construction of the bisaminal skeleton in the CDEFG ring moiety and a stereocontrolled construction of the densely functionalized C ring, which contains four quaternary chiral centers. During the course of our studies, we have already developed an excellent methodology for bisaminal formation (Scheme 1), [3] and have reported a synthesis of the ABC ring moiety in the preceding paper.[5] Herein, we report the total synthesis of (À)-norzoanthamine from the key intermediate 8.Our synthetic strategy for the preparation of 1, starting from 8, is shown in Scheme 2. (À)-Norzoanthamine could be synthesized from a ketoacid 4 or its equivalent based on our efficient method of bisaminal formation. The cyclization precursor 4, in turn, could be derived from the aldehyde 5 by the Horner-Emmons reaction with nitrogen-containing ketophosphonate 6, which can be prepared from lactone 9.[6] As mentioned in the preceding paper, we envisioned that the cyclopentanol moiety in tetracyclic 8 might serve as a handle for introducing the remaining C1-C7 fragment. Thus, oxidative cleavage of cyclopentanone 7 and subsequent functional group transformation would provide the requisite aldehyde 5. For these manipulations, the key intermediate 8 was first converted into cyclopentanone 7, in which the a,b-unsaturated cyclohexenone moiety in ring A is masked as cyclohexanol after introducing the methyl group at C26. Synthesis of aldehyde 5, a substrate for the HornerEmmons reaction, was commenced with 1,4-addition of enone 8 for introducing the methyl group at C26 (Scheme 3). Treatment of enone 8 with Gilman reagent led to the corresponding ketone in 91 % yield, which was then Scheme 1. Model study of bisaminal formation. Boc = tert-butoxycarbonyl.Scheme 2. Retrosynthetic analysis. MOM = methoxymethyl, TBDPS = tert-butyldiphenylsilyl, TBS = tert-butyldimethylsilyl.

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