A Wohlfahrtiimonas chitiniclastica with a novel type of blaVEB–1-carrying plasmid isolated from a zebra in China

BackgroundWohlfahrtiimonas chitiniclastica is an emerging fly-borne zoonotic pathogen, which causes infections in immunocompromised patients and some animals. Herein, we reported a W. chitiniclastica BM-Y from a dead zebra in China.MethodsThe complete genome sequencing of BM-Y showed that this isolate carried one chromosome and one novel type of blaVEB–1-carrying plasmid. Detailed genetic dissection was applied to this plasmid to display the genetic environment of blaVEB–1.ResultsThree novel insertion sequence (IS) elements, namely ISWoch1, ISWoch2, and ISWoch3, were found in this plasmid. aadB, aacA1, and gcuG were located downstream of blaVEB–1, composing a gene cassette array blaVEB–1–aadB–aacA1–gcuG bracketed by an intact ISWoch1 and a truncated one, which was named the blaVEB–1 region. The 5′-RACE experiments revealed that the transcription start site of the blaVEB–1 region was located in the intact ISWoch1 and this IS provided a strong promoter for the blaVEB–1 region.ConclusionThe spread of the blaVEB–1-carrying plasmid might enhance the ability of W. chitiniclastica to survive under drug selection pressure and aggravate the difficulty in treating infections caused by blaVEB–1-carrying W. chitiniclastica. To the best of our knowledge, this is the first report of the genetic characterization of a novel blaVEB–1-carrying plasmid with new ISs from W. chitiniclastica

A clinical Pseudomonas juntendi strain with blaIMP−1 carried by an integrative and conjugative element in China

ObjectiveTo precisely determine the species of a carbapenem-resistant Pseudomonas strain 1809276 isolated from the urine of a Chinese patient and analyze its integrative and conjugative element (ICE) 1276 formation mechanism.MethodsSingle-molecule real-time (SMRT) sequencing was carried out on strain 18091276 to obtain the complete chromosome and plasmid (pCN1276) sequences, and average nucleotide identity (ANI) was used for precise species identification. The ICEs in GenBank with the same integrase structure as ICE 1276 were aligned. At the same time, the transfer ability of blaIMP−1 and the antibiotic sensitivity of Pseudomonas juntendi 18091276 were tested.ResultsThis bacterium was P. juntendi, and its drug resistance mechanism is the capture of the accA4' gene cassette by the Tn402-like type 1 integron (IntI1-blaIMP−1) to form In1886 before its capture by the ΔTn4662a-carrying ICE 1276. The acquisition of blaIMP−1 confers carbapenem resistance to P. juntendi 18091276.ConclusionThe formation of blaIMP−1-carrying ICE 1276, its further integration into the chromosomes, and transposition and recombination of other elements promote bacterial gene accumulation and transmission

New Generation Perovskite Solar Cells with Solution-Processed Amino-substituted Perylene Diimide Derivative as Electron-Transport Layer

In this research work, for the first time, we introduced amino-substituted perylene diimide derivative (N-PDI) as an alternative electron transport layer (ETL) to replace the commonly used TiO2 in planar heterojunction perovskite solar cells. Two types of device structures i.e., glass/FTO/N-PDI/CH3NH3PbI3-xClx/spiro-MeOTAD/Au, and polyethylene terephthalate (PET)/ITO/N-PDI/CH3NH3PbI3-xClx/spiro-MeOTAD/Au, were fabricated on both rigid and flexible substrates using room-temperature solution processing technique. Based on the proposed device structures, the power conversion efficiency (PCE) of 17.66% was obtained based on glass/FTO rigid substrates, and a PCE of 14.32% was achieved based on PET/ITO flexible substrates. Results revealed that the terminal amino group in N-PDI resulting in the enhanced wetting capability of surfaces to perovskite, and the lower the surface work function of FTO substrate as well as passivate the surface trap states of perovskite films. Our results confirm that small molecule semiconductor N-PDI can serve as an effective electron-transport material for achieving high-performance perovskite solar cells and draw molecular design guidelines for electron-selective contacts with perovskite

Controllable synthesis of indium oxide nanorod‐flowers for high field emission performance

Abstract In this paper, indium oxide (In2O3) nanomaterials are successfully synthesized on the silicon substrates by hydrothermal method and calcination. By changing the ratio of raw materials, In2O3 exhibits three morphologies of nanorods, nanomaces, and nanorod‐flowers. Among the three morphologies of In2O3 nanomaterials, the nanorod‐flowers shaped In2O3 shows a strong field emission property, the turn‐on electric field as low as 0.97 V/µm and the field enhancement factor β up to 1053. The excellent performance is attributed to the higher length to diameter (L/D) ratio of the emitting tips and the better crystal quality for nanorod‐flowers shaped In2O3. The authors also show that for the nanorod‐flowers shaped In2O3, increasing separation distance, the turn‐on electric field increases up to about 3.67 V/µm and β decreases to 573 at d = 900 µm. This work provides new insights to design and synthesize nanomaterials with excellent field emission properties

Microstructure and Properties of Semisolid A356 Alloy Strip Affected by Nozzle Temperature of a Novel Micro Fused-Casting

The semisolid A356 alloy strip was prepared by a novel continuous micro fused-casting process. The microstructure evolution and mechanical property of A356 aluminum alloy strip with different nozzle temperatures were investigated. The nozzle temperature had great influences on the microstructure and property primarily accompanied with the crystal change in the fused-casting area through the cooling conditions. The results showed that the semisolid A356 alloy strip samples fabricated by micro fused-casting demonstrated good performances and uniform structures with the nozzle temperature at 593 degrees C and the stirring velocity at 700 r/min. The fine grains of the primary alpha-Al phase with average grain size of 51 mu m and shape factor up to 0.71 were obtained under the micro fused-casting process, and the ultimate average vickers hardness came up to 83.39 +/- 0.89 HV, and the tensile strength and elongation of the A356 alloy strip reached 245.32 MPa and 7.85%, respectively

Non-Fullerene Polymer Solar Cells Based on Alkylthio and Fluorine Substituted 2D-Conjugated Polymers Reach 9.5% Efficiency

Non-fullerene polymer solar cells (PSCs) with solution-processable n-type organic semiconductor (n-OS) as acceptor have seen rapid progress recently owing to the synthesis of new low bandgap n-OS, such as ITIC. To further increase power conversion efficiency (PCE) of the devices, it is of a great challenge to develop suitable polymer donor material that matches well with the low bandgap n-OS acceptors thus providing complementary absorption and nanoscaled blend, morphology, as well as suppressed recombination and minimized energy loss. To address this challenge, we synthesized three medium bandgap 2D-conjugated bithienyl-benzo dithiophene-alt-fluorobenzotriazole copolymers J52, J60, and J61 for the application as donor in the PSCs with low bandgap n-OS ITIC as acceptor. The three polymers were designed with branched alkyl 052), branched alkylthio (J60), and linear alkylthio (J61) substituent on the thiophene conjugated side chain of the benzodithiophene (BDT) units for studying effect of the substituents on the photovoltaic performance of the polymers. The alkylthio side chain, red-shifted absorption down-shifted the highest occupied molecular orbital (HOMO) level and improved crystallinity of the 2D conjugated polymers. With linear alkylthio side chain, the tailored polymer J61 exhibits an enhanced J(sc) of 17.43 mA/cm(2), a high V-oc of 0.89 V, and a PCE of 9.53% in the best non-fullerene PSCs with the polymer as donor and ITIC as acceptor. To the best of our knowledge, the PCE of 9.53% is one of the highest values reported in literature to date for the non-fullerene PSCs. The results indicate that J61 is a promising medium bandgap polymer donor in non-fullerene PSCs.clos

Side-Chain Isomerization on an n-type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar Cells

Low bandgap n-type organic semiconductor (n-OS) ITIC has attracted great attention for the application as an acceptor with medium bandgap p-type conjugated polymer as donor in nonfullerene polymer solar cells (PSCs) because of its attractive photovoltaic performance. Here we report a modification on the molecular structure of ITIC by side-chain isomerization with meta-alkyl-phenyl substitution, m-ITIC, to further improve its photovoltaic performance. In a comparison with its isomeric counterpart ITIC with para-alkyl-phenyl substitution, m-ITIC shows a higher film absorption coefficient, a larger crystalline coherence, and higher electron mobility. These inherent advantages of m-ITIC resulted in a higher power conversion efficiency (PCE) of 11.77% for the nonfullerene PSCs with m-ITIC as acceptor and a medium bandgap polymer J61 as donor, which is significantly improved over that (10.57%) of the corresponding devices with ITIC as acceptor. To the best of our knowledge, the PCE of 11.77% is one of the highest values reported in the literature to date for nonfullerene PSCs. More importantly, the m-ITIC-based device shows less thickness-dependent photovoltaic behavior than ITIC-based devices in the active-layer thickness range of 80-360 nm, which is beneficial for large area device fabrication. These results indicate that m-ITIC is a promising low bandgap n-OS for the application as an acceptor in PSCs, and the side-chain isomerization could be an easy and convenient way to further improve the photovoltaic performance of the donor and acceptor materials for high efficiency PSCs.close

Insights into the working mechanism of cathode interlayers in polymer solar cells via [(C8H17)(4)N](4)[SiW12O40]

A low-cost (amp;lt;$1 per g), high-yield (amp;gt;90%), alcohol soluble surfactant-encapsulated polyoxometalate complex [(C8H17)(4)N](4)[SiW12O40] has been synthesized and utilized as a cathode interlayer (CIL) in polymer solar cells (PSCs). A power conversion efficiency of 10.1% can be obtained for PSCs based on PTB7-Th (poly[[2,6-4,8-di(5-ethylhexylthienyl) benzo[1,2-b;3,3-b]-dithiophene][3-fluoro-2[(2-ethylhexyl) carbonyl] thieno [3,4-b]-thiophenediyl]]):PC71BM ([6,6]-phenyl C71-butyric acidmethyl ester) due to the incorporation of [(C8H17)(4)N](4)[SiW12O40]. Combined measurements of current density-voltage characteristics, transient photocurrent, charge carrier mobility and capacitance-voltage characteristics demonstrate that [(C8H17)(4)N](4)[SiW12O40] can effectively increase the built-in potential, charge carrier density and mobility and accelerate the charge carrier extraction in PSCs. Most importantly, the mechanism of using [(C8H17)(4)N](4)[SiW12O40] as the CIL is further brought to light by X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) of the metal/ [(C8H17)(4)N](4)[SiW12O40] interface. The findings suggest that [(C8H17)(4)N](4)[SiW12O40] not only decreased the work function of the metal cathodes but also was n-doped upon contact with the metals, which provide insights into the working mechanism of the CILs simultaneously improving the open circuit voltage, short circuit current and fill factor in the PSCs.Funding Agencies|National Basic Research Program of China [2014CB643505]; Natural Science Foundation of China [51273077]</p