Chemical Abundances of Planetary Nebulae in the Substructures of M31

We present deep spectroscopy of planetary nebulae (PNe) that are associated with the substructures of the Andromeda Galaxy (M31). The spectra were obtained with the OSIRIS spectrograph on the 10.4 m GTC. Seven targets were selected for the observations, three in the Northern Spur and four associated with the Giant Stream. The most distant target in our sample, with a rectified galactocentric distance >100 kpc, was the first PN discovered in the outer streams of M31. The [O III] 4363 auroral line was well detected in the spectra of all targets, enabling electron temperature determination. Ionic abundances are derived based on the [O III] temperatures, and elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon are estimated. The relatively low N/O and He/H ratios as well as abundance ratios of alpha-elements indicate that our target PNe might belong to populations as old as ~2 Gyr. Our PN sample, including the current seven and the previous three observed by Fang et al., have rather homogeneous oxygen abundances. The study of abundances and the spatial and kinematical properties of our sample leads to the tempting conclusion that their progenitors might belong to the same stellar population, which hints at a possibility that the Northern Spur and the Giant Stream have the same origin. This may be explained by the stellar orbit proposed by Merrett et al. Judging from the position and kinematics, we emphasize that M32 might be responsible for the two substructures. Deep spectroscopy of PNe in M32 will help to assess this hypothesis.Comment: Accepted for publication in the ApJ. 23 pages, including 13 figures and 7 table

Palladium-Catalyzed Decarboxylative Alkoxycarbonylation of Potassium Aryltrifluoroborates with Potassium Oxalate Monoesters

Palladium-catalyzed decarboxylative alkoxycarbonylation of potassium aryltrifluoroborates with potassium oxalate monoesters in the presence of potassium persulfate was performed under mild conditions. A number of benzoyl esters with a wide variety of substituents at different positions were efficiently synthesized with this method. Mechanism of the palladium-catalyzed decarboxylative carbonylation of aryltrifluoroborates was studied, and a radical-mediated Pd(II)/Pd(IV) catalytic cycle was proposed

Exciton-Phonon Interaction Model for Singlet Fission in Prototypical Molecular Crystals

In singlet fission (SF), a spin-conserving splitting of one singlet exciton into two triplet excitation states, the transition between localized electronic states can be controlled and modulated by delocalized lattice phonons. In this work, we built an exciton–phonon (ex–ph) interaction model accounting local electronic states coupled with both local molecular vibrations and low frequency intermolecular phonon modes for SF in crystalline tetracene and rubrene. On the basis of the calculated electronic couplings at the equilibrium structure of the molecular dimer, a superexchange path for SF was found for tetracene while couplings between the triplet pair (TT) state and other diabatic states are zero for rubrene due to the high symmetry. Our further ex–ph spectral density analysis and quantum dynamics simulation based on our ex–ph interaction model suggested a thermal-activated mechanism for SF in rubrene crystal via symmetry breaking by nuclear vibration, which is in agreement with recent experiments. It is also shown that thermal fluctuations of electronic couplings in both tetracene and rubrene are mostly in the same order of magnitude at room temperature, and this could be one of the reasons for both tetracene and rubrene to exhibit SF time scales within a close range (hundreds to thousands of femtoseconds) in experiments

The Feasibility of Imaging Myocardial Ischemic/Reperfusion Injury Using \u3csup\u3e99m\u3c/sup\u3eTc-labeled Duramycin in a Porcine Model

When pathologically externalized, phosphatidylethanolamine (PE) is a potential surrogate marker for detecting tissue injuries. 99mTc-labeled duramycin is a peptide-based imaging agent that binds PE with high affinity and specificity. The goal of the current study was to investigate the clearance kinetics of 99mTc-labeled duramycin in a large animal model (normal pigs) and to assess its uptake in the heart using a pig model of myocardial ischemia–reperfusion injury. Methods The clearance and distribution of intravenously injected 99mTc-duramycin were characterized in sham-operated animals (n = 5). In a closed chest model of myocardial ischemia, coronary occlusion was induced by balloon angioplasty (n = 9). 99mTc-duramycin (10–15 mCi) was injected intravenously at 1 hour after reperfusion. SPECT/CT was acquired at 1 and 3 hours after injection. Cardiac tissues were analyzed for changes associated with acute cellular injuries. Autoradiography and gamma counting were used to determine radioactivity uptake. For the remaining animals, 99mTc-tetrafosamin scan was performed on the second day to identify the infarct site. Results Intravenously injected 99mTc-duramycin cleared from circulation predominantly via the renal/urinary tract with an α-phase half-life of 3.6 ± 0.3 minutes and β-phase half-life of 179.9 ± 64.7 minutes. In control animals, the ratios between normal heart and lung were 1.76 ± 0.21, 1.66 ± 0.22, 1.50 ± 0.20 and 1.75 ± 0.31 at 0.5, 1, 2 and 3 hours post-injection, respectively. The ratios between normal heart and liver were 0.88 ± 0.13, 0.80 ± 0.13, 0.82 ± 0.19 and 0.88 ± 0.14. In vivo visualization of focal radioactivity uptake in the ischemic heart was attainable as early as 30 min post-injection. The in vivo ischemic-to-normal uptake ratios were 3.57 ± 0.74 and 3.69 ± 0.91 at 1 and 3 hours post-injection, respectively. Ischemic-to-lung ratios were 4.89 ± 0.85 and 4.93 ± 0.57; and ischemic-to-liver ratios were 2.05 ± 0.30 to 3.23 ± 0.78. The size of 99mTc-duramycin positive myocardium was qualitatively larger than the infarct size delineated by the perfusion defect in 99mTc-tetrafosmin uptake. This was consistent with findings from tissue analysis and autoradiography. Conclusion 99mTc-duramycin was demonstrated, in a large animal model, to have suitable clearance and biodistribution profiles for imaging. The agent has an avid target uptake and a fast background clearance. It is appropriate for imaging myocardial injury induced by ischemia/reperfusion

A Prospective Randomized Study of Adjuvant Chemotherapy in Resected Stage IIIA-N2 Non-small Cell Lung Cancer

Background and objective Lung cancer is one of the leading cause of cancer-related death around the world. Surgery is the primary treatment for patients with stage I, II, or IIIA non-small cell lung cancer (NSCLC). However, longterm survival of NSCLC patients after surgery alone is largely unsatisfactory. We undertook to determine whether adjuvant vinorelbine/paclitaxel plus carboplatin prolong overall survival among patients with completely resected stage IIIA-N2 nonsmall cell lung cancer. Methods We randomly assigned patients with completely resected stage IIIA-N2 non-small cell lung cancer to vinorelbine/paclitaxel plus carboplatin or to observation. Results A total of 150 patients (1999-2003) underwent randomization to vinorelbine/paclitaxel plus carboplatin (79 patients) or observation. In both groups, the median age was 57 years, 73 percent were male, and 28 percents had squamous carcinoma. Chemotherapy caused neutropenia in 82 percents of patients (including grade 3 and 4 neutropenia in 42 percent) and there was no treatment-related death observed in this trial. After median follow-up of 39 months (range 1-110), overall survival was significantly prolonged in the chemotherapy group as compared with the observation group (33 months versus 24 months, χ2=4.363, P=0.037), as was disease-free survival (32 months versus 20 months, χ2=5.413, P=0.020). Five-year overall survival rates were 31.1 percent and 19.1 percent, respectively. Conclusion Adjuvant vinorelbine/paclitaxel plus carboplatin have an acceptable level of toxicity and prolongs disease-free and overall survival among patients with completely resected stage IIIA-N2 non-small cell lung cancer

Cathode ray tube addressed liquid crystal light valve projection display

Integrating an epitaxially grown monocrystalline garnet cathode ray tube\u27s (CRT\u27s) high resolution and a liquid crystal light valve\u27s (LCLV\u27s) large screen and high brightness, we develop a CRT optically addressed LCLV projection display system. The CRT\u27s phosphor screen is green chrome yttrium aluminum garnet (Cr:YAG) fabricated by liquid phase epitaxy. The LCLV\u27s fabrication and the optical system\u27s design are given. The projection display system shows good performances

Design and real-time implementation of data-driven adaptive wide-area damping controller for back-to-back VSC-HVDC

This paper proposes a data-driven adaptive wide-area damping controller (D-WADC) for back-to-back VSC-HVDC to suppress the low frequency oscillation in a large-scale interconnected power system. The proposed D-WADC adopts a dual-loop control structure to make full use of the active and reactive power control of VSC-HVDC to improve the damping of the power system. A data-driven algorithm named the goal representation heuristic dynamic programming is employed to design the proposed D-WADC, which means the design procedure only requires the input and output data rather than the mathematic model of the concerned power system. Thus, the D-WADC can adapt to the change of operating condition through online weight modification. Besides, the adaptive delay compensator (ADC) is added to effectively compensate the stochastic delay involved in the wide-area feedback signal. Case studies are conducted based on the simplified model of a practical power system and the 16-machine system with a back-to-back VSC-HVDC. Both the simulation and hardware-in-loop experiment results verify that the proposed D-WADC can effectively suppress the low-frequency oscillation under a wide range of operating conditions, disturbances, and stochastic communication delays

Transcriptome analysis of Rpl11-deficient zebrafish model of Diamond-Blackfan Anemia

AbstractTo comprehensively reflect the roles of Rpl11 on the transcriptome of zebrafish model of Diamond-Blackfan Anemia (DBA), we performed whole-genome transcriptome sequencing on the Illumina Hi-Seq 2000 sequencing platform. Two different transcriptomes of zebrafish Rpl11-deficient and control Morpholino (Mo) embryos were collected and analyzed. The experimental design and methods, including sample preparation, RNA-Seq data evaluation and treatment, were described in details so that representative high-throughput sequencing data were acquired for assessing the actual impacts of Rpl11 on zebrafish embryos. We provided the accession number GSE51326 for easy access to the database