Resilient High Catalytic Performance of Platinum Nanocatalysts with Porous Graphene Envelope.

Despite the innumerable developments of nanosized and well dispersed noble metal catalysts, the degradation of metal nanoparticle catalysts has proven to be a significant obstacle for the commercialization of the hydrogen fuel cell. Here, the formation of Pt nanoparticle catalysts with a porous graphene envelope has been achieved using a single step low temperature vaporization process. While these Pt-Gr core-shell nanoparticles possess superior resilience to degradation, it comes at the cost of degraded overall catalyst efficacy. However, it is possible to combat this lower overall performance through inclusion of low concentrations of nitrogen precursor in the initial stage of single-step synthesis, inhibiting the formation of complete graphene shells, as verified by atomic resolution aberration-corrected transmission electron microscopy (AC-TEM) imaging. The resultant porous graphene encapsulated Pt catalysts are found to have both the high peak performance of the bare Pt nanoparticle catalysts and the increased resilience of the fully shielded Pt-Gr core-shells, with the optimal N-doped Pt-Gr yielding a peak efficiency of 87% compared to bare Pt, and maintaining 90% of its catalytic activity after extended potential cycling. The nitrogen treated Pt-Gr core-shells thus act as an effective substitute catalyst for conventional bare Pt nanoparticles, maintaining their catalytic performance over prolonged use

Large-Scale Genomics Reveals the Genetic Characteristics of Seven Species and Importance of Phylogenetic Distance for Estimating Pan-Genome Size

For more than a decade, pan-genome analysis has been applied as an effective method for explaining the genetic contents variation of prokaryotic species. However, genomic characteristics and detailed structures of gene pools have not been fully clarified, because most studies have used a small number of genomes. Here, we constructed pan-genomes of seven species in order to elucidate variations in the genetic contents of >27,000 genomes belonging to Streptococcus pneumoniae, Staphylococcus aureus subsp. aureus, Salmonella enterica subsp. enterica, Escherichia coli and Shigella spp., Mycobacterium tuberculosis complex, Pseudomonas aeruginosa, and Acinetobacter baumannii. This work showed the pan-genomes of all seven species has open property. Additionally, systematic evaluation of the characteristics of their pan-genome revealed that phylogenetic distance provided valuable information for estimating the parameters for pan-genome size among several models including Heaps' law. Our results provide a better understanding of the species and a solution to minimize sampling biases associated with genome-sequencing preferences for pathogenic strains.

Hybrid organic-inorganic light-emitting electrochemical cells using fluorescent polymer and ionic liquid blend as an active layer

We demonstrate enhanced device performance by using a blend of emissive polymer and mobile ionic liquid molecules in hybrid organic-inorganic polymeric light-emitting electrochemical cells with high air stability. The mobile anions and cations redistributed near each electrode/active layer interface make ohmic contacts, thereby enhancing current density and electroluminescence efficiency at relatively low operating voltage.open12

Efficient hybrid organic-inorganic light emitting diodes with self-assembled dipole molecule deposited metal oxides

We investigate the effect of self-assembled dipole molecules (SADMs) on ZnO surface in hybrid organic-inorganic polymeric light-emitting diodes (HyPLEDs). Despite the SADM being extremely thin, the magnitude and orientation of SADM dipole moment effectively influenced the work function of the ZnO. As a consequence, the charge injection barrier between the conduction band of the ZnO and the lowest unoccupied molecular orbital of poly(9,9(')-dioctylfluorene)-co-benzothiadiazole could be efficiently controlled resulting that electron injection efficiency is remarkably enhanced. The HyPLEDs modified with a negative dipolar SADM exhibited enhanced device performances, which correspond to approximately a fourfold compared to those of unmodified HyPLEDs.open442

Investigation of Responsiveness to Thyrotropin-Releasing Hormone in Growth Hormone-Producing Pituitary Adenomas

Objective. The aim of this study was to investigate how the paradoxical response of GH secretion to TRH changes according to tumor volumes. Methods. Patients with newly diagnosed acromegaly were classified as either TRH responders or nonresponders according to the results of a TRH stimulation test (TST), and their clinical characteristics were compared according to responsiveness to TRH and tumor volumes. Results. A total of 41 acromegalic patients who underwent the TST were included in this study. Between TRH responders and nonresponders, basal GH, IGF-I levels, peak GH levels, and tumor volume were not significantly different, but the between-group difference of GH levels remained near significant over the entire TST time. during the TST were significantly different according to the responsiveness to TRH. Peak GH levels and during the TST showed significantly positive correlations with tumor volume with higher levels in macroadenomas than in microadenomas. GH levels over the entire TST time also remained significantly higher in macroadenomas than in microadenomas. Conclusion. Our data demonstrated that the paradoxical response of GH secretion to TRH in GH-producing pituitary adenomas was not inversely correlated with tumor volumes

High performance polymer light-emitting diodes with N-type metal oxide/conjugated polyelectrolyte hybrid charge transport layers

We present an interfacial engineering strategy employing n-type-metal-oxide/conjugated-polyelectrolyte (CPE) hybrid charge-transport layers for highly efficient polymer light-emitting diodes (PLEDs). The hybrid metal-oxide/CPE layer facilitates electron-injection, while blocking hole-transport, and thereby maximizes electron-hole recombination within the emitting layer. A series of metal-oxide/CPE combinations were tested in inverted PLEDs (FTO/metal-oxide/CPF8BT/MoO3/Au). Specifically, HfO2/CPE double layer achieved an electroluminescence (EL) efficiency of up to 25.8 cd/A (@ 6.4 V, one of the highest values reported for fluorescent PLEDs).open11