2-Phenyl-1,3-selenazole-4-carb­oxy­lic acid

In the title compound, C10H7NO2Se, the two rings are twisted, making a dihedral angle of 12.42 (9)°. In the crystal, pairs of mol­ecules are disposed about an inversion center, generating O—H⋯O hydrogen-bonded dimers

Tris(1,10-phenanthroline-κ2 N,N′)zinc(II) chloride 2-phenyl-4-selenazole-5-car­box­yl­ate decahydrate

The asymmetric unit of the title salt, [Zn(C12H8N2)3](C10H6NO2Se)Cl·10H2O, contains a [Zn(phen)3]2+ cation (phen is 1,10-phenanthroline), uncoordinated chloride and 2-phenyl-4-selenazole-5-carboxyl­ate anions and ten uncoord­in­ated water mol­ecules. The central ZnII ion is six-coordinated by six N atoms from three phen ligands in a distorted octa­hedral geometry. An extensive O—H⋯O, O—H⋯N and O—H⋯Cl hydrogen-bonding network stabilizes the crystal structure

Towards the Properties of Long Gamma-Ray Burst Progenitors with Swift Data

We investigate the properties of both the prompt and X-ray afterglows of gamma-ray bursts (GRBs) in the burst frame with a sample of 33 Swift GRBs. Assuming that the steep decay segment in the canonical X-ray afterglow lightcurves is due to the curvature effect, we fit the lightcurves with a broken power-law to derive the zero time of the last emission epoch of the prompt emission (t1) and the beginning as well as the end time of the shallow decay segment (t2 and t3).We show that both the isotropic peak gamma-ray luminosity and gamma-ray energy are correlated with the isotropic X-ray energy of the shallow decay phase and the isotropic X-ray luminosity at t2. We infer the properties of the progenitor stars based on a model proposed by Kumar et al. who suggested that both the prompt gamma-rays and the X-ray afterglows are due to the accretions of different layers of materials of the GRB progenitor star by a central black hole (BH). We find that most of the derived masses of the core layers are 0.1-5 solar mass with a radius of 10^8-10^10 cm. The rotation parameter is correlated with the burst duration, being consistent with the expectation of collapsar models. The estimated radii and the masses of the fall-back materials for the envelope layers are 10^10-10^12 cm and 10^-3~1 solar mass, respectively. The average accretion rates in the shallow decay phase are correlated with those in the prompt gamma-ray phase, but they are much lower. The derived radii of the envelope are smaller than the photospheric radii of Wolf-Rayet (WR) stars. It is interesting that the assembled mass density profile for the bursts in our sample is also well consistent with the simulation for a pre-supernova star with 25 solar mass.Comment: 12 pages in MNRAS two-column style, 8 figures, 3 tables, accepted for publication in MNRA

Distribution patterns of small-molecule ligands in the protein universe and implications for origin of life and drug discovery

Ligand-protein mapping was found to follow a power law and the preferential attachment principle, leading to the identification of the molecules, mostly nucleotide-containing compounds, that are likely to have evolved earliest

Treatment-naive first episode depression classification based on high-order brain functional network

BACKGROUND: Recent functional connectivity (FC) studies have proved the potential value of resting-state functional magnetic resonance imaging (rs-fMRI) in the study of major depressive disorder (MDD); yet, the rs-fMRI-based individualized diagnosis of MDD is still challenging. METHODS: We enrolled 82 treatment-naïve first episode depression (FED) adults and 72 matched normal control (NC). A computer-aided diagnosis framework was utilized to classify the FEDs from the NCs based on the features extracted from not only traditional "low-order" FC networks (LON) based on temporal synchronization of original rs-fMRI signals, but also "high-order" FC networks (HON) that characterize more complex functional interactions via correlation of the dynamic (time-varying) FCs. We contrasted a classifier using HON feature (CHON) and compared its performance with using LON only (CLON). Finally, an integrated classification model with both features was proposed to further enhance FED classification. RESULTS: The CHON had significantly improved diagnostic accuracy compared to the CLON (82.47% vs. 67.53%). Joint classification further improved the performance (83.77%). The brain regions with potential diagnostic values mainly encompass the high-order cognitive function-related networks. Importantly, we found previously less-reported potential imaging biomarkers that involve the vermis and the crus II in the cerebellum. LIMITATIONS: We only used one imaging modality and did not examine data from different subtypes of depression. CONCLUSIONS: Depression classification could be significantly improved by using HON features that better capture the higher-level brain functional interactions. The findings suggest the importance of higher-level cerebro-cerebellar interactions in the pathophysiology of MDD