Solar-CO2 -to-Syngas Conversion Enabled by Precise Charge Transport Modulation.

The rational design of the directional charge transfer channel represents an important strategy to finely tune the charge migration and separation in photocatalytic CO2 -to-fuel conversion. Despite the progress made in crafting high-performance photocatalysts, developing elegant photosystems with precisely modulated interfacial charge transfer feature remains a grand challenge. Here, a facile one-pot method is developed to achieve in situ self-assembly of Pd nanocrystals (NYs) on the transition metal chalcogenide (TMC) substrate with the aid of a non-conjugated insulating polymer, i.e., branched polyethylenimine (bPEI), for photoreduction of CO2 to syngas (CO/H2 ). The generic reducing capability of the abundant amine groups grafted on the molecular backbone of bPEI fosters the homogeneous growth of Pd NYs on the TMC framework. Intriguingly, the self-assembled TMCs@bPEI@Pd heterostructure with bi-directional spatial charge transport pathways exhibit significantly boosted photoactivity toward CO2 -to-syngas conversion under visible light irradiation, wherein bPEI serves as an efficient hole transfer mediator, and simultaneously Pd NYs act as an electron-withdrawing modulator for accelerating spatially vectorial charge separation. Furthermore, in-depth understanding of the in situ formed intermediates during the CO2 photoreduction process are exquisitely probed. This work provides a quintessential paradigm for in situ construction of multi-component heterojunction photosystem for solar-to-fuel energy conversion.

Robust and Stable Atomically Precise Metal Nanoclusters Mediated Solar Water Splitting.

Atomically precise metal nanoclusters (NCs) represent an emerging sector of light-harvesting antennas by virtue of peculiar atomic stacking fashion, quantum confinement effect, and molecular-like discrete energy band structure. Nevertheless, precise control of charge carriers over metal NCs has yet to be achieved by the short carrier lifetime and intrinsic instability of metal NCs, which renders the complexity of metal NCs-based photosystems with photoredox mechanisms remaining elusive. Herein, fine tuning of charge migration over metal NCs is demonstrated by constructing directional charge transfer channels in multilayered heterostructure enabled by a facile layer-by-layer (LbL) assembly approach, wherein oppositely charged branched poly-ethylenimine (BPEI) and glutathione (GSH)-capped gold NCs [Aux NCs, Au25 (GSH)18 NCs] are alternately deposited on the metal oxide (MOs: TiO2 , WO3 , Fe2 O3 ) substrates. TheAux (Au25 ) NCs layer serves as light-harvesting antennas for engendering charge carriers, andBPEI interim layer uniformly intercalated at the interface of Aux NCs layer constitutes the tandem hole transport channel for motivating the charge transfer cascade, resulting in the considerably enhanced photoelectrochemical water oxidation performances. Besides, poor photo-stability of Aux NCs is surmounted by stimulating the hole transfer kinetics process.

Alloy Metal Nanocluster: A Robust and Stable Photosensitizer for Steering Solar Water Oxidation.

Metal nanoclusters (NCs) have been unleashed as an emerging category of metal materials by virtue of integrated merits including the unusual atom-stacking mode, quantum confinement effect, and fruitful catalytically active sites. Nonetheless, development of metal NCs as photosensitizers is blocked by light-induced instability and ultrashort carrier lifespan, which remarkably retards the design of metal NC-involved photosystems, hence resulting in the decreased photoactivities. To solve these obstacles, herein, we conceptually probed the charge transfer characteristics of the BiVO4 photoanode photosensitized by atomically precise alloy metal NCs, wherein tailor-made l-glutathione-capped gold-silver bimetallic (AuAg) NCs were controllably self-assembled on the BiVO4 substrate. It was uncovered that alien Ag atom doping is able to effectively stabilize the alloy AuAg NCs and simultaneously photosensitize the BiVO4 photoanode, significantly boosting the photoelectrochemical (PEC) water oxidation performances. The reasons for the robust and stable PEC water oxidation activities of the AuAg NCs/BiVO4 composite photoanode were unambiguously unleashed. We ascertain that Ag atom doping in the staple motif of Aux NCs efficaciously protects the NCs from rapid oxidation, enhancing the photostability, boosting the photosensitization efficiency, and thus leading to the considerably improved PEC water splitting activities compared with the homometallic counterpart. This work could afford a new strategy to judiciously tackle the inherent detrimental instability of metal NCs for solar energy conversion.

Atomically Precise Metal Nanoclusters versus Metal Nanocrystals: Maneuvering Tunable Charge Transfer in an Integrated Photosystem.

Atomically precise metal nanoclusters (NCs) have recently emerged as a promising sector of metal nanomaterials in terms of peculiar atomic stacking fashion, quantum confinement effect, and enriched catalytically active sites, which are wholly distinct from conventional metal nanocrystals (NYs) in all respects. However, atomically precise metal NCs inevitably suffer from intrinsic poor instability either under light irradiation or thermal treatment owing to the ultrahigh surface energy, thereby resulting in substantial loss of photosensitization efficiency and retarding their emerging utilization in photoredox catalysis. Here, we first conceptually reveal the charge transfer characteristic difference between atomically precise metal NCs and metal NYs attained by self-transformation in boosting interfacial charge migration and separation. The results signify that the interfacial charge transfer impetus of atomically precise metal NCs as a photosensitizer versus metal NYs as a Schottky-type electron-withdrawing mediator is closely associated with the loading amount on the semiconductor substrate. The photosensitization effect of atomically precise metal NCs is superior to the electron trapping capability of metal NYs when the loading amount of the metal ingredient is relatively high and vice versa. Our work would significantly bridge the gap between atomically precise metal NCs and metal NYs in fine tuning of the charge transfer pathway in photocatalysis toward solar energy conversion.

Steering Photocatalytic CO2 Conversion over CsPbBr3 Perovskite Nanocrystals by Coupling with Transition-Metal Chalcogenides.

Transition-metal chalcogenides (TMCs) have received enormous attention by virtue of their large light absorption coefficient, abundant catalytically active sites, and markedly reduced spatially vectorial charge-transfer distance originating from generic structural merits. However, the controllable construction of TMC-based heterostructured photosystems for photocatalytic carbon dioxide (CO2) reduction is retarded by the ultrashort charge lifetime, sluggish charge-transfer kinetics, and low target product selectivity. Herein, we present the rational design of two-dimensional (2D)/zero-dimensional (0D) heterostructured CO2 reduction photosystems by an electrostatic self-assembly strategy, which is enabled by precisely anchoring CsPbBr3 quantum dots (QDs) on the 2D TMC (CdIn2S4, ZnIn2S4, In2S3) frameworks. The peculiar 2D/0D integration mode and suitable energy-level alignment between these two assembly units afford maximal interfacial contact and applicable potential for CO2 photoreduction, thus endowing the self-assembled TMCs/CsPbBr3 nanocomposites with considerably improved visible-light-driven photocatalytic performances toward CO2 reduction to carbon monoxide with high selectivity. The enhanced photocatalytic performances of TMCs/CsPbBr3 heterostructures are attributed to the abundant active sites on the TMC frameworks, excellent light absorption of CsPbBr3 QDs, and well-defined 2D/0D heterostructures of TMCs/CsPbBr3 QDs photosystems, which synergistically boosts the directional charge transport from CsPbBr3 QDs to TMCs, enhancing the interfacial charge migration/separation. Our work would inspire the construction of novel TMCs-involved photosystems for solar-to-fuel conversion.

Unleashing non-conjugated polymers as charge relay mediators.

The core factors affecting the efficiency of photocatalysis are predominantly centered on controllable modulation of anisotropic spatial charge separation/transfer and regulating vectorial charge transport pathways in photoredox catalysis, yet it still meets with limited success. Herein, we first conceptually demonstrate the rational design of unidirectional cascade charge transfer channels over transition metal chalcogenide nanosheets (TMC NSs: ZnIn2S4, CdS, CdIn2S4, and In2S3), which is synergistically enabled by a solid-state non-conjugated polymer, i.e., poly(diallyldimethyl ammonium chloride) (PDDA), and MXene quantum dots (MQDs). In such elaborately designed photosystems, an ultrathin PDDA layer functions as an intermediate charge transport mediator to relay the directional electron transfer from TMC NSs to MQDs that serve as the ultimate electron traps, resulting in a considerably boosted charge separation/migration efficiency. The suitable energy level alignment between TMC NSs and MQDs, concurrent electron-withdrawing capabilities of the ultrathin PDDA interim layer and MQDs, and the charge transport cascade endow the self-assembled TMC/PDDA/MQD heterostructured photosystems with conspicuously improved photoactivities toward anaerobic selective reduction of nitroaromatics to amino derivatives and photocatalytic hydrogen evolution under visible light irradiation. Furthermore, we ascertain that this concept of constructing a charge transfer cascade in such TMC-insulating polymer-MQD photosystems is universal. Our work would afford novel insights into smart design of spatial vectorial charge transport pathways by precise interface modulation via non-conjugated polymers for solar energy conversion.

Precisely Modulating the Photosensitization Efficiency of Transition-Metal Chalcogenide Quantum Dots toward Solar Water Oxidation.

Precisely modulating the spatial charge migration/separation constitutes the central issue in dictating the solar conversion efficiency of photoelectrochemical (PEC) cells, whereas it still remains a grand challenge. Here, we conceptually demonstrate the construction of hierarchically ordered metal oxide (MO)/transition-metal chalcogenide quantum dots (TMC QDs) multilayered heterostructured photoanodes, that is, MO/[TMC QDs(+)/TMC QDs(-)]n (TMC QDs: CdTe, CdSe, CdS), by a simple and general bottom-up self-assembly route. Tailor-made intrinsically oppositely charged TMC QDs are alternately deposited on the highly ordered MO via a generic ligand-triggered electrostatic interaction to craft heterostructured photoanodes. The charge-transfer pathway stimulated by the photosensitization of TMC QDs is finely tuned by the assembly sequence. The advantageous multilayered nanoarchitecture renders the MO/[TMC QDs(+)/TMC QDs(-)]n photoanodes exhibit substantially enhanced PEC performances under light irradiation, owing to the applicable energy-level configuration and peculiar combination fashion between building blocks and considerably boosted interfacial charge separation resulting from generating spatial tandem charge transport. Furthermore, photosensitization efficiency comparison among TMC QDs is comprehensively performed with PEC mechanisms elucidated.

miR­155­5p downregulation inhibits epithelial­to­mesenchymal transition by targeting SIRT1 in human nasal epithelial cells.

Epithelial-to-mesenchymal transition (EMT) in nasal epithelial cells is involved with tissue remodeling of nasal polyps. The present study investigated the molecular mechanisms through which miR­155­5p regulated EMT in chronic rhinosinusitis (CRS). Patients were divided into the following groups: CRSsNP, CRS without nasal polyposis group, CRSwNP, CRS with nasal polyposis and controls. The expression of transforming growth factor (TGF)­ß1, EMT markers, sirtuin 1 (SIRT1) and miR­155­5p were determined by western blotting and reverse transcription­quantitative PCR. Cell morphology following TGF­ß1 treatment in the presence of miR­155­5p inhibitors or controls was observed under a microscope. Target genes and potential binding sites between miR­155­5p and SIRT1 were predicted by TargetScan and confirmed using dual­luciferase reporter assay. In patients with CRS, the expression levels of E­cadherin were downregulated and the expression levels of TGF­ß1, mesenchymal markers and miR­155­5p were upregulated. Additionally, these changes in expression levels were reduced or increased to a greater extent in the CRSwNP group compared with the CRSsNP group. Furthermore, TGF­ß1 expression promoted EMT in human nasal epithelial cells (HNEpCs) and upregulated miR­155­5p expression. These effects were reversed by miR­155­5p inhibitors. Additionally, SIRT1 was predicted as a target gene of miR­155­5p. Downregulation of miR­155­5p upregulated epithelial marker expression and downregulated mesenchymal marker expression by regulating SIRT1. Therefore, the downregulation of miR­155­5p inhibited EMT in HNEpCs by targeting SIRT1.

lncRNA DGCR5 inhibits the proliferation of colorectal cancer cells by downregulating miR-21.

Long non-coding RNA (lncRNA) DiGeorge syndrome critical region gene 5 (DGCR5) serves roles as a tumor suppressor or oncogene in different types of cancer. The current study aimed to explore the role of DGCR5 in colorectal cancer (CRC). It was revealed that the expression of DGCR5 was downregulated, while microRNA (miR)-21 was upregulated in CRC. The expression level of DGCR5 in tumor tissue decreased, while expression levels of miR-21 increased, with advancing stages of the disease. The expression levels of DGCR5 and miR-21 were inversely associated in tumor tissues. In CRC cells in vitro, miR-21 overexpression failed to significantly affect DGCR5, while DGCR5 overexpression resulted in reduced expression levels of miR-21. DGCR5 overexpression showed no significant effects on cancer cell migration and invasion, but suppressed cancer cell proliferation in vitro. miR-21 overexpression increased cancer cell proliferation and attenuated the effects of DGCR5 overexpression. Therefore, lncRNA DGCR5 may inhibit the proliferation of CRC cells by downregulating miR-21.

[Preliminary Study of Lonicera hypoglauca on Germination Conditions of Sand Culture Seeds and Sterilization Method of Sand Culture Seedling Sterilization].

OBJECTIVE: To explore the germination conditions of Lonicera hypoglauca sand culture seeds and the effects of sand culture seedlings sterilization. METHODS: 0.1% HgCl2 with different sterilization time, different illumination time and temperature culture condition were adopted to study the germination conditions of sand culture seeds. Different sterilization treatments and different hardening-seedling days were used to test the sterilization effect of sand culture seedlings. RESULTS: The sterilization effect of the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min on Lonicera hypoglauca seeds was the optimum,with the average pollution rate of 15.56%, and the average germination rate reached 51.11%. The combination of varied temperature-room temperature under light for 12 h/d was the best, with the average germination rate peaked at 75.49%, and the average germination potential reached 68.36%. The treatment of detergent liquor scrub-tap water wash on the part above the hypocotyl, which was sand cultured under the opening condition and had no root, showed the best sterilization effect, with the average pollution rate was zero, and the average survival rate peaked at 100.00%. The sterilization effect of sand culture seedlings, which was disinfected after cleaning by detergent liquor scrub-tap water wash after hardening-seeding for 30 days, was the best, with the average pollution rate of 50.00%, and the average survival rate of 100.00%. CONCLUSION: The best sterilization effect is the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min; Lighting for 12 h/d of varied temperature-room temperature is regarded as the optimum culture condition. The treatment of detergent liquor scrub-tap water wash treatment on the part above the hypocotyl,which is sand cultured under the opening condition and had no root, shows the best sterilization effect. For the sand culture seedlings, before inoculated in subculture medium, should be hardening-seedling for some days and sterilized after detergent liquor scrub-tap water wash.

Decreased expression of BATF2 is significantly associated with poor prognosis in oral tongue squamous cell carcinoma.

BATF2, also called SARI, is associated with several cancer types, and loss of BATF2 expression is frequently detected in aggressive and metastatic cancers. The expression of BATF2 was previously shown to slow the growth rate of malignant tumor cells injected into athymic nude mice, and decreased expression of BATF2 has been correlated to poor prognosis in hepatocellular carcinoma. However, the functional role of BATF2 in oral tongue squamous cell carcinoma (OTSCC) remains unknown. In the present study, we examined BATF2 expression in 16 fresh, paired OTSCC and adjacent non-tumor tissues, as well as in a normal tongue epithelial cell line and in 5 OTSCC cell lines by quantitative PCR and western blot analysis. We also evaluated BATF2 expression in 202 paraffin­embedded OTSCC and 30 adjacent non-tumor samples by immunohistochemistry, and its relationship with clinicopathological features and prognosis was investigated. We found that BATF2 expression was significantly reduced in the majority of the 16 OTSCC tumor tissues and the 5 OTSCC cell lines when compared with the non-tumor tissues and the normal tongue epithelial cell line, respectively. Consistent with these results, our immunohistochemistry analysis revealed that decreased BATF2 expression was present in 124 of the 202 cases and was significantly correlated with poor tumor differentiation (P=0.002). Patients with decreased BATF2 expression showed reduced survival when compared to those with high expression (P<0.001). Multivariate analysis revealed that BATF2 expression is an independent predictor of overall survival (P=0.001). These results demonstrate that BATF2 plays a tumor-suppressor role in the development of OTSCC and that BATF2 may serve as a prognostic biomarker and potential therapeutic target for this disease.

[Determination of chlorogenic acid and luteoloside in lonicerae flos of different habitats and germplasms].

OBJECTIVE: To establish an UPLC-PDA method for simultaneous determination of chlorogenic acid and luteoloside in Lonicerae Flos. On the basis of developed method, the quality of Lonicerae Flos from nine habitats and two local germplasms introduced from Qufu in Shandong to Wuming in Guangxi was evaluated. METHODS: The analysis was performed on a Waters Acquity UPLC H-Class system. An Acquity UPLC BEH RP18 (100 mm x 2.1 mm,1.7 µm) column was used for all analyses. The investigated compounds were separated with a gradient mobile phase consisting of acetonitrile and 0.4% phosphoric acid solution at a flow rate of 0.2 mL/min, and the detection wavelength was set at 242 nm. RESULTS: The quality of Lonicerae Flos from Qufu was the best among Lonicerae Flos of nine habitats for its content of chlorogenic acid and luteoloside at 35.715 and 1.270 mg/g, respectively. The content of chlorogenic acid and luteoloside in Lonicerae Flos of "Jiufengyihao" and "Shuxing" introduced from Qufu to Wuming both complied with the standard of Chinese Pharmacopoeia (2010 edition). CONCLUSION: The developed UPLC-PDA method is simple, reliable and repeatable, which is helpful for the quality control of Lonicerae Flos. "Jiufengyihao" and "Shuxing" are potential germplasms for the introduction of Lonicerae Flos in Wuming.

[Transporter associated with antigen processing 1 637A/G gene polymorphisms and susceptibility to nasopharyngeal carcinoma in Han population in Yunnan Province, China].

OBJECTIVE: To study the relationship between 637A/G gene polymorphisms of the transporter associated with antigen processing 1 gene and nasopharyngeal carcinomas (NPC) and to find out the susceptible genes of NPC in Han population in Yunnan Province, China. METHODS: Two hundred and thirty-three cases with NPC and 296 cases matched cancer-free controls were genotyped for the TAP1 637A/G polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Epstein-Barr virus infection was detected by PCR. The adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated by using unconditional logistic regression model. RESULTS: Contrast with homozygous TAP1 637 AA, G allele significantly increasing risk of NPC was associated with homozygous 637 GG OR = 4.26 (95%CI were 2.08 - 8.66, P < 0.001) and heterozygous 637 AG OR = 1.56 (95%CI were 1.12 - 2.33, P < 0.05). The subjects at least having one TAP1 637 G allele had OR of 1.88 (95%CI were 1.35 - 2.82, P < 0.001). Furthermore, EBV infection may increase the risk of developing NPC interacting with TAP1 637 A/G polymorphism OR = 2.76(95% CI were 1.69 - 4.63, P < 0.001). CONCLUSIONS: The TAP1 637G allele is associated with the NPC in Han population in Yunnan China, EBV pathogenesis in NPC might be facilitated by polymorphisms in the TAP1 proteins.