Annealing Effect on Photovoltaic Performance of CdSe Quantum-Dots-Sensitized TiO2 Nanorod Solar Cells

Large area rutile TiO₂ nanorod arrays were grown on F:SnO₂ (FTO) conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs) were deposited onto single-crystalline TiO₂ nanorod arrays by a chemical bath deposition (CBD) method to make a photoelectrode. The solar cell was assembled using a CdSe-TiO₂ nanostructure as the photoanode and polysulfide solution as the electrolyte. The annealing effect on optical and photovoltaic properties of CdSe quantum-dotssensitized TiO₂ nanorod solar cells was studied systematically. A significant change of the morphology and a regular red shift of band gap of CdSe nanoparticles were observed after annealing treatment. At the same time, an improved photovoltaic performance was obtained for quantum-dots-sensitized solar cell using the annealed CdSe-TiO₂ nanostructure electrode. The power conversion efficiency improved from 0.59% to 1.45% as a consequence of the annealing effect. This improvement can be explained by considering the changes in the morphology, the crystalline quality, and the optical properties caused by annealing treatment

SPAN: A Stochastic Projected Approximate Newton Method

Second-order optimization methods have desirable convergence properties. However, the exact Newton method requires expensive computation for the Hessian and its inverse. In this paper, we propose SPAN, a novel approximate and fast Newton method. SPAN computes the inverse of the Hessian matrix via low-rank approximation and stochastic Hessian-vector products. Our experiments on multiple benchmark datasets demonstrate that SPAN outperforms existing first-order and second-order optimization methods in terms of the convergence wall-clock time. Furthermore, we provide a theoretical analysis of the per-iteration complexity, the approximation error, and the convergence rate. Both the theoretical analysis and experimental results show that our proposed method achieves a better trade-off between the convergence rate and the per-iteration efficiency.Comment: Appeared in the AAAI 2020, 25 pages, 6 figure

Mutations in porin LamB contribute to ceftazidime-avibactam resistance in KPC-producing Klebsiella pneumoniae.

Ceftazidime-avibactam (CAZ-AVI) shows promising activity against carbapenem-resistant Klebsiella pneumoniae (CRKP), however, CAZ-AVI resistance have emerged recently. Mutations in KPCs, porins OmpK35 and/or OmpK36, and PBPs are known to contribute to the resistance to CAZ-AVI in CRKP. To identify novel CAZ-AVI resistance mechanism, we generated 10 CAZ-AVI-resistant strains from 14 CAZ-AVI susceptible KPC-producing K. pneumoniae (KPC-Kp) strains through in vitro multipassage resistance selection using low concentrations of CAZ-AVI. Comparative genomic analysis for the original and derived mutants identified CAZ-AVI resistance-associated mutations in KPCs, PBP3 (encoded by ftsI), and LamB, an outer membrane maltoporin. CAZ-AVI susceptible KPC-Kp strains became resistant when complemented with mutated blaKPC genes. Complementation experiments also showed that a plasmid borne copy of wild-type lamB or ftsI gene reduced the MIC value of CAZ-AVI in the induced resistant strains. In addition, blaKPC expression level increased in four of the six CAZ-AVI-resistant strains without KPC mutations, indicating a probable association between increased blaKPC expression and increased resistance in these strains. In conclusion, we here identified a novel mechanism of CAZ-AVI resistance associated with mutations in porin LamB in KPC-Kp

MR Imaging Radiomics Signatures for Predicting the Risk of Breast Cancer Recurrence as Given by Research Versions of MammaPrint, Oncotype DX, and PAM50 Gene Assays

To investigate relationships between computer-extracted breast magnetic resonance (MR) imaging phenotypes with multigene assays of MammaPrint, Oncotype DX, and PAM50 to assess the role of radiomics in evaluating the risk of breast cancer recurrence

Wielding the sword: President Xi’s new anti-corruption campaign

A state achieves legitimacy through multiple sources, one of which is the effectiveness of its governance. Generations of scholars since Hobbes have identified the maintenance of peace and order as core functions of a legitimate state. In the modern world, economic prosperity, social stability and effective control of corruption often provide adequate compensation for a deficit of democracy. Corruption closely correlates with legitimacy. While a perceived pervasive, endemic corruption undermines the legitimacy of a regime, a successful anti-corruption campaign can allow a regime to recover from a crisis of legitimacy (Gilley 2009; Seligson and Booth 2009). This is the rationale behind the periodical campaigns against corruption that have been conducted by the Chinese Communist Party (‘Party’ or ‘CCP’) (Manion 2004; Wedeman 2012). Political leaders in China have found it expedient to use anti-corruption campaigns to remove their political foes, to rein in the bureaucracy and to restore public confidence in their ability to rule. Through anti-corruption campaigns, emerging political leaders consolidate their political power, secure loyalty from political factions and regional political forces, and enhance their legitimacy in the eyes of the general public. In an authoritarian state that experiences a high level of corruption, an anti-corruption campaign is a delicate political battle that addresses two significant concerns. The first concern is to orchestrate the campaign so that it is regime-reinforcing instead of regime-undermining. To remain credible, the regime must demonstrate its willingness and capacity to punish corrupt officials at the highest levels.preprin