Nitrogen-Embedded Quintuple [7]Helicene: A Helicene-Azacorannulene Hybrid with Strong Near-Infrared Fluorescence.

Herein, a nitrogen-embedded quintuple [7]helicene (N-Q7H) with an azapentabenzocorannulene core, which can be considered to be a helicene/azacorannulene hybrid π-system, was synthesized from azapentabenzocorannulene in a three-step process. N-Q7H is the first example of a multiple helicene with an azabuckybowl core. Single-crystal X-ray diffractometry unambiguously confirmed the structure of the propeller-shaped hybrid π-system. Owing to nitrogen-atom doping in the multiple helicenes and effective hybridization between the helicene and azacorannulene, N-Q7H exhibits considerably redshifted absorption and emission (yellow-to-green color change and green-to-near-infrared fluorescence change) relative to the azapentabenzocorannulene core. The broad absorption from the ultraviolet-visible to the NIR region is ascribable to the allowed transition between the highest occupied molecular orbital and the lowest unoccupied molecular orbital after symmetry breaking, as revealed by density functional theory calculations. Compared to previous propeller-shaped multiple helicenes with corannulene or hexabenzocoronene (etc.) as cores, N-Q7H demonstrates a significantly higher NIR fluorescence quantum efficiency of 28%. Additionally, the chiral-resolution and redox properties of N-Q7H were investigated. The excellent photophysical and inherent chiral properties of N-Q7H suggest that azapentabenzocorannulene can be used as an outstanding nitrogen-embedded core to construct novel multiple helicenes with wide application potential, including as NIR fluorescent bio-probes.

Improving Thermal and Photostability of Polymer Solar Cells by Robust Interface Engineering.

As the power conversion efficiency (PCE) of organic photovoltaics (OPVs) approaches 19%, increasing research attention is being paid to enhancing the device's long-term stability. In this study, a robust interface engineering of graphene oxide nanosheets (GNS) is expounded on improving the thermal and photostability of non-fullerene bulk-heterojunction (NFA BHJ) OPVs to a practical level. Three distinct GNSs (GNS, N-doped GNS (N-GNS), and N,S-doped GNS (NS-GNS)) synthesized through a pyrolysis method are applied as the ZnO modifier in inverted OPVs. The results reveal that the GNS modification introduces passivation and dipole effects to enable better energy-level alignment and to facilitate charge transfer across the ZnO/BHJ interface. Besides, it optimizes the BHJ morphology of the photoactive layer, and the N,S doping of GNS further enhances the interaction with the photoactive components to enable a more idea BHJ morphology. Consequently, the NS-GNS device delivers enhanced performance from 14.5% (control device) to 16.5%. Moreover, the thermally/chemically stable GNS is shown to stabilize the morphology of the ZnO electron transport layer (ETL) and to endow the BHJ morphology of the photoactive layer grown atop with a more stable thermodynamic property. This largely reduces the microstructure changes and the associated charge recombination in the BHJ layer under constant thermal/light stresses. Finally, the NS-GNS device is demonstrated to exhibit an impressive T80 lifetime (time at which PCE of the device decays to 80% of the initial PCE) of 2712 h under a constant thermal condition at 65 °C in a glovebox and an outstanding photostability with a T80 lifetime of 2000 h under constant AM1.5G 1-sun illumination in an N2 -controlled environment.

Inflammasome activation involved in early inflammation reaction after liver transplantation.

Liver transplantation has emerged as a vital therapy for end-stage liver diseases. Acute -phase inflammation play an important role in liver graft injury.Recent studies have revealed that inflammasome are responsible for initiating inflammation in early stage of acute organ rejection in liver transplantation, however the underlying mechanism remains unclear. Here we explored to block inflammasome activation to see whether it can alleviate early inflammation reaction during rejection of allgrafts in a rat model and gain further insights into the mechanism of inhibiting inflammation in allografts. By using Ac-YVAD-CMK, a highly selective caspase-1 inhibitor, to inhibit inflammation reaction involved in allograft rejection in a rat model. Our results showed that the rejection activity index (RAI) of Ac-YVAD-CMK-treated allografts is significantly diminished in similar magnitude to that of isografts. Compared with isografts, the expression of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and IL-1ß in allograft group increased significantly with the development of rejection, exhibiting apparent correlation. Expression of IFN-γ mRNA in untreated allografts was maximal on day 3 while in Ac-YVAD-CMK-treated allografts and isografts, IFN-γ mRNA levels remained low over the duration of the time course. ELISA results revealed serum elevation of IL-1ß by day 7 after othotopic liver transplantation (OLT) in comparison with isografts. There were no statistically significant differences between isografts and Ac-YVAD-CMK-treated allografts. For the first time, our data reveal that inhibition of the inflammasome activation pathway attenuates inflammation reaction of hepatic transplant rejection.

[Expression of Toll-like receptors in mononuclear cells from children with acute rotavirus diarrhea].

OBJECTIVE: Rotavirus is the single most common cause of severe dehydrating diarrhea in young children worldwide, but the pathogenesis and immunity against this disease are not completely understood. A prospective study was conducted to assess gene expression of toll-like receptors (TLR) in children with acute rotavirus diarrhea. METHODS: Seventy-five children with acute rotavirus diarrhea and 38 control children were enrolled in this study from Sep. 2004 to Jan. 2005. All the 75 patients had detailed records of clinical characteristics. Rotavirus antigen was detected by ELISA from stools. Peripheral blood mononuclear cells (PBMC) were separated by Ficoll reagent and RNA was extracted by Trizol. The levels of mRNA for five TLRs in PBMC were examined by fluorescent quantitative RT-PCR. RESULTS: Patients with acute rotavirus infection had elevated mean levels of TLR 2, 3, 4, 7, 8 mRNA expressions in PBMC within 3 days since onset of the disease, P less than 0.05. But only TLR 2, 3, 8 mRNA levels remained increased in patients within 7 or 14 days since onset (P less than 0.05). Mean levels of mRNA for TLR 4 in PBMC was higher in patients with more severe diarrhea including longer duration of diarrhea, more episodes of diarrhea per day and higher severity scores (P less than 0.05). CONCLUSION: Manifold TLR may play roles in the start-up and regulation of immune responses in children with acute rotavirus diarrhea. These findings will be helpful to further recognize immune response in Chinese children with rotavirus diarrhea and, consequently, may provide directions and insights that could prove critical to the prevention or treatment of this important disease.