Cepheids in M31: The PAndromeda Cepheid Sample

We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r P1, i P1, and g P1 bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the method developed by Kodric et al., we identify Cepheids by using a three-dimensional parameter space of Fourier parameters of the Cepheid light curves combined with a color cut and other selection criteria. This is an unbiased approach to identify Cepheids and results in a homogeneous Cepheid sample. The period–luminosity relations obtained for our sample have smaller dispersions than in our previous work. We find a broken slope that we previously observed with HST data in Kodric et al., albeit with a lower significance

Carbon-Nanotube-Embedded Hydrogel Sheets for Engineering Cardiac Constructs and Bioactuators

We engineered functional cardiac patches by seeding neonatal rat cardiomyocytes onto carbon nanotube (CNT)-incorporated photo-cross-linkable gelatin methacrylate (GelMA) hydrogels. The resulting cardiac constructs showed excellent mechanical integrity and advanced electrophysiological functions. Specifically, myocardial tissues cultured on 50 μm thick CNT-GelMA showed 3 times higher spontaneous synchronous beating rates and 85% lower excitation threshold, compared to those cultured on pristine GelMA hydrogels. Our results indicate that the electrically conductive and nanofibrous networks formed by CNTs within a porous gelatin framework are the key characteristics of CNT-GelMA leading to improved cardiac cell adhesion, organization, and cell–cell coupling. Centimeter-scale patches were released from glass substrates to form 3D biohybrid actuators, which showed controllable linear cyclic contraction/extension, pumping, and swimming actuations. In addition, we demonstrate for the first time that cardiac tissues cultured on CNT-GelMA resist damage by a model cardiac inhibitor as well as a cytotoxic compound. Therefore, incorporation of CNTs into gelatin, and potentially other biomaterials, could be useful in creating multifunctional cardiac scaffolds for both therapeutic purposes and in vitro studies. These hybrid materials could also be used for neuron and other muscle cells to create tissue constructs with improved organization, electroactivity, and mechanical integrity.United States. Army Research Office. Institute for Soldier NanotechnologiesNational Institutes of Health (U.S.) (HL092836)National Institutes of Health (U.S.) (EB02597)National Institutes of Health (U.S.) (AR057837)National Institutes of Health (U.S.) (HL099073)National Science Foundation (U.S.) (DMR0847287)United States. Office of Naval Research (ONR PECASE Award)United States. Office of Naval Research (Young Investigator award)National Research Foundation of Korea (grant (NRF-2010-220-D00014)

Identification and characterization of a mechanical transmissible begomovirus causing leaf curl on oriental melon

Oriental melon plants, Cucumis melo var. makuwa cv. Silver Light, showing virus-induced symptoms of mosaic, leaf curl and puckering were observed in the fields of eastern Taiwan in 2007. A virus culture, designated as SL-1, isolated from the diseased melon was established in systemic host plants, Nicotiana benthamiana and oriental melon, by mechanical inoculation. SL-1 did not react to the antisera against common cucurbit-infecting RNA viruses. Viral DNAs extracted from the diseased plant were amplified with the degenerate primers for begomoviruses. The full-length genomic DNA-A and DNA-B of SL-1 were sequenced and found to be closest, with 97.7% and 90.6% nucleotide identity, respectively, to Tomato leaf curl New Delhi begomovirus (ToLCNDV) cucumber isolate from a group of cucurbit-infecting begomoviruses. The virus SL-1 was designated as ToLCNDV oriental melon isolate (ToLCNDV-OM). The pathogenicity of ToLCNDV-OM was confirmed by agroinfection. Progeny virus from the agroinfected N. benthamiana plants was able to infect oriental melon by mechanical inoculation and caused symptoms similar to the original diseased melon in the field. The ToLCNDV-OM also infected five other species of cucurbitaceous plants by mechanical inoculation. This is the first report of a new ToLCNDV isolate causing severe disease on oriental melon in Taiwan