Mechanistic Investigation of RhI-Catalyzed Cycloisomerization of Benzylallene-Internal Alkynes via C-H Activation

Treatment of the benzylallene-internal alkynes with [RhCl(CO)2]2 effected a cycloisomerization via a Csp2-H bond activation to produce the tricyclo[9.4.0.03,8]pentadecapentaene skeleton. The reaction mechanism via formation of the rhodabicyclo[4.3.0] intermediates and σ-bond metathesis between the Csp2-H bond on the benzene ring and the Csp2-RhIII bond was proposed. In addition, a plausible alternative mechanism for the previously reported cycloisomerization of the benzylallene-terminal alkynes could also be proposed. © 2017 American Chemical Society.Embargo Period 12 month

Morphological and molecular phylogenetic studies of a red alga, Halymenia durvillei, (Halymeniaceae, Halymeniales) from Indo-Pacific

Morphological and molecular phylogenetic studies were made on recently collected Halymenia plants widely from Japan, the Philippines, Indonesia, Malaysia and Thailand. Although the external morphology (branching pattern, blade width, or degree of dentation) was very variable, no special differences were found in their vegetative and reproductive structures. The features are close to Halymenia durvillei. Our rbcL gene sequence analysis has shown that the branched Halymenia plants are all included in a distinct, monophyletic clade, separate from those including the foliose plants. The branched plants studied here are, therefore, concluded to belong in a single species, Halymenia durvillei, irrespective of their great external variations. As Halymenia microcarpa clearly fall within the range of external variations of H. durvillei, it was concluded to be synonymous with H. durvillei. The taxonomic interrelationship among the four varieties (var. formosa, var. ceylanica, var. denudata and var. edentata) remained unresolved, although apprently encompassed within the morphological range of H. durvillei

Preliminary report on the molecular phylogeny of the Laurencia complex (Rhodomelaceae)

A molecular phylogenetic analysis of three closely related red algal genera, Laurencia, Chondrophycus and Osmundea (Rhodomelaceae) that are often called the Laurencia complex or Laurencia sensu lato, mainly of the north-western Pacific species, was carried out based on rbcL gene sequences. The sequence data downloaded from GenBank were also included in our analysis. The monophyly of the clade of Osmundea species was supported by high bootstrap value. All examined species of Laurencia sensu stricto with typical features (four periaxial cells per vegetative axial segment, longitudinally oriented secondary pit-connections between contiguous superficial cortical cells, corps en cerise within superficial cortical and trichoblast cells) also constituted a monophyletic clade with high bootstrap value. On the other hand, Chondrophycus species were divided into two separated clades with relatively high bootstrap values respectively. Furthermore, L. flexilis, which has four periaxial cells per vegetative axial segment but lacks secondary pit-connections between contiguous superficial cortical cells, constituted an independent monophyletic clade with high bootstrap value. These results suggest that only two groups, Osmundea and the typical Laurencia, are monophyletic and Chondrophycus is polyphyletic within the Laurencia complex. The phylogenetic position of L. flexilis, an intermediate species between the typical Laurencia and Chondrophycus, must be clarified to determine the key features to distinguish Chondrophycus and Laurencia sensu stricto. Further investigations based on the other genes are expected

J1406+0102: Dust Obscured Galaxy Hiding Super Eddington Accretion System with Bright Radio Emission

Recent high-$z$ quasar observations strongly indicate that super-Eddington accretion is a crucial phase to describe the existence of supermassive black holes (SMBHs) with $M_\mathrm{BH} \gtrsim 10^9 M_\odot$ at $z \gtrsim 7$. Motivated by the theoretical suggestion that the super-Eddington phase efficiently produces outflows and jets bright in radio bands, we search and find a super-Eddington radio-loud dust-obscured galaxy (DOG) J1406+0102 at $z=0.236$, through cross-matching of the infrared-bright DOGs of Noboriguchi et al. (2019) with the VLA/FIRST 1.4 GHz radio and the SDSS optical spectral catalog. DOG J1406+0102 shows broad components in the Balmer lines. Assuming those lines are from the broad line region, it gives BH mass estimation of $\log\ (M_\mathrm{BH}/M_\odot)=7.30 \pm 0.25$, and AGN luminosity of $\log (L_\mathrm{bol,[OIII]}/\mathrm{erg}~\mathrm{s}^{-1}) = 45.91\pm0.38$ estimated from the intrinsic [OIII] luminosity, resulting in super-Eddington accretion of $\lambda_\mathrm{Edd}\simeq 3$. We show that 1) DOG J1406+0102 is operating strong AGN feedback: the [OIII] outflow velocity exceeds the escape velocity of the host galaxy halo and the kinetic efficiency is obtained as $\approx$ 8% that can be sufficient to quench the host galaxy, 2) the expected future growth pathway of DOG J1406+0102 would join an over-massive BH trajectory and 3) radio-loud DOGs can provide a significant contribution to the high-energy ($\gtrsim$ 100 TeV) cosmic neutrino background if we assume DOG J1406+0102 as a representative of radio-loud DOGs.Comment: 10 pages, 5 figures, submitted to ApJ