Cobalt sulfide materials have attracted enormous interest as low‐cost alternatives to noble‐metal catalysts capable of catalyzing both oxygen reduction and oxygen evolution reactions. Although recent advances have been achieved in the development of various cobalt sulfide composites to expedite their oxygen reduction reaction properties, to improve their poor oxygen evolution reaction (OER) activity is still challenging, which significantly limits their utilization. Here, the synthesis of Fe3O4‐decorated Co9S8 nanoparticles in situ grown on a reduced graphene oxide surface (Fe3O4@Co9S8/rGO) and the use of it as a remarkably active and stable OER catalyst are first reported. Loading of Fe3O4 on cobalt sulfide induces the formation of pure phase Co9S8 and highly improves the catalytic activity for OER. The composite exhibits superior OER performance with a small overpotential of 0.34 V at the current density of 10 mA cm−2 and high stability. It is believed that the electron transfer trend from Fe species to Co9S8 promotes the breaking of the Co–O bond in the stable configuration (Co–O–O superoxo group), attributing to the excellent catalytic activity. This development offers a new and effective cobalt sulfide‐based oxygen evolution electrocatalysts to replace the expensive commercial catalysts such as RuO2 or IrO2.

Resistance switching characteristics of natural sericin protein film is demonstrated for nonvolatile memory application for the first time. Excellent memory characteristics with a resistance OFF/ON ratio larger than 10(6) have been obtained and a multilevel memory based on sericin has been achieved. The environmentally friendly high performance biomaterial based memory devices may hold a place in the future of electronic device development.

A highly sensitive and tailorable pressure sensor is designed based on the variation of contact resistance between an Au covered micropillar array and a conductive polymer film. The sensitivity of such pressure sensors can be tuned from 0.03 kPa−1 to 17 kPa−1 at pressures less than 1 kPa, and a limit of detection of 2 Pa has been demonstrated.

application. [ 1,2 ] However, bulk or microsize red P materials suffer from dramatic capacity reduction and poor cyclability with continued usage [ 1h ] due to their electronic insulation (≈10 −14 S cm −1 ) [ 1f ] and irreversible reaction related to the pulverization of particles, [ 1c , 3 ] which is caused by drastic volume change (>300%) [ 1h ] during cycling process. In light of this, black P is an alternative electrode material for high-performance LIB application due to its high electrical conductivity (≈10 2 S cm −1 ) [ 1h , 4 ] and fast kinetics during the Li + intercalating process. [ 4a,c ] Nevertheless, the traditional high-pressure method (>1 GPa, Scheme 1 a) through a pressure-induced structure-change mechanism is extremely diffi cult as it relies on specifi cally designed apparatus under controlled temperature (≥200 °C). [ 4c , 5 ] Recently, a facile mineralizer-assisted gas-phase transformation method was developed to produce large-size bulk black P. [ 6 ] However, the resultant particles by the above approaches are more than tens of micrometers in size, [ 5a , 6 ] which renders them unsuitable for high-rate LIB application. Therefore, material nanostructuring and engineering of the red/black P toward the improvement of electrical/ionic conductivity and the alleviation of volume expansion is desired for high-rate LIBs. [ 7 ] To this end, conductive confi gurations of nanostructured phosphorus materials (amorphous or red P, P-C composites, and metal phosphide, Scheme 1 a) [ 1d,e , 2e , 8 ] with buffering of volume change are widely explored through mechanical approaches (e.g., hand-grinding, mechanical milling, etc., as shown in Table S1, Supporting Information). [ 1f , 2a , 3,9 ] Furthermore, an emerging high energy mechanical milling by generating the suffi cient pressure (≈6 GPa) and temperature, [ 1c ] (Scheme 1 a), could even produce the most thermodynamically stable black P or composites with the particles size down to subhundred nanometer, which showed improved LIB performance. [ 1c,h ] Impressively, these nanostructured phosphorus or its composites [ 1d,e , 8 ] could realize high capacity (>1000 mAh g −1 ) as well as long-cycling life (>100 cycles) for LIBs. However, these top-down mechanical approaches remain diffi cult with respect to obtaining largescale uniform distribution of phosphorus nanostructures, as Phosphorus-based materials are promising for high-performance lithium-ion battery (LIB) applications due to their high theoretical specifi c capacity. Currently, the existing physical methods render great diffi culty toward rational engineering on the nanostructural phosphorus or its composites, thus limiting its high-rate LIB applications. For the fi rst time, a sublimation-induced synthesis of phosphorus-based composite nanosheets by a chemistry-based solvothermal reaction is reported. Its formation mechanism involves solidvapor-solid transformation driven by continuous vaporization-condensation process, as well as subsequent bottom-up assembly growth. The proof-o...

dHydrosalpinx induction in mice by Chlamydia muridarum infection, a model that has been used to study C. trachomatis pathogenesis in women, is known to depend on the cryptic plasmid that encodes eight genes designated pgp1 to pgp8. To identify the plasmid-encoded pathogenic determinants, we evaluated C. muridarum transformants deficient in the plasmid-borne gene pgp3, -4, or -7 for induction of hydrosalpinx. C. muridarum transformants with an in-frame deletion of either pgp3 or -4 but not -7 failed to induce hydrosalpinx. The deletion mutant phenotype was reproduced by using transformants with premature termination codon insertions in the corresponding pgp genes (to minimize polar effects inherent in the deletion mutants). Pgp4 is known to regulate pgp3 expression, while lack of Pgp3 does not significantly affect Pgp4 function. Thus, we conclude that Pgp3 is an effector virulence factor and that lack of Pgp3 may be responsible for the attenuation in C. muridarum pathogenicity described above. This attenuated pathogenicity was further correlated with a rapid decrease in chlamydial survival in the lower genital tract and reduced ascension to the upper genital tract in mice infected with C. muridarum deficient in Pgp3 but not Pgp7. The Pgp3-deficient C. muridarum organisms were also less invasive when delivered directly to the oviduct on day 7 after inoculation. These observations demonstrate that plasmid-encoded Pgp3 is required for C. muridarum survival in the mouse genital tract and represents a major virulence factor in C. muridarum pathogenesis in mice.

b Transformation of Chlamydia trachomatis should greatly advance the chlamydial research. However, significant progress has been hindered by the failure of C. trachomatis to induce clinically relevant pathology in animal models. Chlamydia muridarum, which naturally infects mice, can induce hydrosalpinx in mice, a tubal pathology also seen in women infected with C. trachomatis. We have developed a C. muridarum transformation system and confirmed Pgp1, -2, -6, and -8 as plasmid maintenance factors, Pgp3, -5, and -7 as dispensable for in vitro growth, and Pgp4 as a positive regulator of genes that are dependent on plasmid for expression. More importantly, we have discovered that Pgp5 can negatively regulate the same plasmid-dependent genes. Deletion of Pgp5 led to a significant increase in expression of the plasmid-dependent genes, suggesting that Pgp5 can suppress the expression of these genes. Replacement of pgp5 with a mCherry gene, or premature termination of pgp5 translation, also increased expression of the plasmid-dependent genes, indicating that Pgp5 protein but not its DNA sequence is required for the inhibitory effect. Replacing C. muridarum pgp5 with a C. trachomatis pgp5 still inhibited the plasmid-dependent gene expression, indicating that the negative regulation of plasmid-dependent genes is a common feature of all Pgp5 regardless of its origin. Nevertheless, C. muridarum Pgp5 is more potent than C. trachomatis Pgp5 in suppressing gene expression. Thus, we have uncovered a novel function of Pgp5 and developed a C. muridarum transformation system for further mapping chlamydial pathogenic and protective determinants in animal models.

Hierarchically porous CuO architectures were successfully fabricated via copper basic carbonate precursor obtained with a facile hydrothermal route. The shape of the precursor is preserved after its conversion to porous CuO architectures by calcination. The obtained CuO are systemically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller N(2) adsorption-desorption analysis. The results reveal that hierarchical CuO microspheres are monoclinic structure and are assembled by porous single-crystal sub-microplatelets. The Brunauer-Emmett-Teller N(2) adsorption-desorption analysis indicates that the obtained CuO has a surface area of 12.0 m(2)/g with pore size of around 30 nm. The gas sensing performance of the as-prepared hierarchical CuO microspheres were investigated towards a series of typical organic solvents and fuels. They exhibit higher sensing response than that of commercial CuO powder. Their sensing properties can be further improved by loading of Ag nanoparticles on them, suggesting their potential applications in gas sensors.

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