Discovery and Follow-up Observations of the Young Type Ia Supernova 2016coj

The Type~Ia supernova (SN~Ia) 2016coj in NGC 4125 (redshift $z=0.004523$) was discovered by the Lick Observatory Supernova Search 4.9 days after the fitted first-light time (FFLT; 11.1 days before $B$-band maximum). Our first detection (pre-discovery) is merely $0.6\pm0.5$ day after the FFLT, making SN 2016coj one of the earliest known detections of a SN Ia. A spectrum was taken only 3.7 hr after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. We performed high-quality photometry, low- and high-resolution spectroscopy, and spectropolarimetry, finding that SN 2016coj is a spectroscopically normal SN Ia, but with a high velocity of \ion{Si}{2} $\lambda$6355 ($\sim 12,600$\,\kms\ around peak brightness). The \ion{Si}{2} $\lambda$6355 velocity evolution can be well fit by a broken-power-law function for up to a month after the FFLT. SN 2016coj has a normal peak luminosity ($M_B \approx -18.9 \pm 0.2$ mag), and it reaches a $B$-band maximum \about16.0~d after the FFLT. We estimate there to be low host-galaxy extinction based on the absence of Na~I~D absorption lines in our low- and high-resolution spectra. The spectropolarimetric data exhibit weak polarization in the continuum, but the \ion{Si}{2} line polarization is quite strong ($\sim 0.9\% \pm 0.1\%$) at peak brightness.Comment: Submitte

Anomalous Josephson effect modulated by magnetic misorientation in a topological unconventional superconductor hybrid structure

We study the anomalous Josephson effect induced by magnetic misorientation of asymmetric s-wave superconductor (SC)/ferromagnet insulator (FI)/normal layer/FI/d-wave SC junctions on a surface of topological insulator (TI). For the out-of-plane case, the magnetic misorientation not only leads to anomalous Josephson effects, but also realizes $0-\pi$ state transitions. However, for the in-plane case, the $0-\pi$ state transitions do not turn up any more. In particular, the plateaus phenomenon for dxy-wave SC junction emerges all the time. In addition, in the context of the in-plane case, the supercurrent rectification can be modulated by the magnetic misorientation. These unique phenomena can be employed to identify different d-wave superconductivities of three-dimensional TI and manufacture the supercurrent devices with such functions as phase storing, rectification, and quantum computation

Effects of 3D culturing conditions on the transcriptomic profile of stem-cell-derived neurons

Understanding neurological diseases requires tractable genetic systems, and engineered three-dimensional (3D) neural tissues are an attractive choice. Yet how the cellular transcriptomic profiles in these tissues are affected by the encapsulating materials and are related to the human brain transcriptome is not well understood. Here, we report the characterization of the effects of different culturing conditions on the transcriptomic profiles of induced neuronal cells and developed a method for the rapid generation of 3D co-cultures of neuronal and astrocytic cells from the same pool of human embryonic stem cells. By comparing the gene-expression profiles of neuronal cells in culture conditions relevant to the developing human brain, we found that modifying the degree of crosslinking of composite hydrogels can tune expression patterns so that they correlate with those of specific brain regions and developmental stages. Moreover, single-cell-sequencing results showed that our engineered tissues recapitulate transcriptional patterns of cell types in the human brain. Analyses of culturing conditions will inform the development of 3D neural tissues for use as tractable models of brain diseases.NIH (Grants 1R01-HG009761, 1R01-MH110049 and 1DP1-HL141201