Spontaneous exciton dissociation in organic photocatalyst under ambient conditions for highly efficient synthesis of hydrogen peroxide.

SignificanceHydrogen peroxide is a highly competitive ready-to-use product for solar energy transformation. Nevertheless, the contemporary photosynthetic systems are not efficient enough, due to severe charge recombination caused by high activation energy and binding energy of the exciton. Herein, we achieve spontaneous exciton dissociation at room temperature. Moreover, the photosynthesis of H2O2 reaches between 9,366 and 12,324 µmol·g-1 from 9 AM to 4 PM in ambient conditions, that is, sunlight irradiation, real water including fresh water and seawater, room temperature, and open air. The ultrahigh photocatalytic efficiency in ambient conditions allows the solar-to-chemical conversion in a real cost-effective and sustainable way, which represents an important step toward real applications.

A solar-to-chemical conversion efficiency up to 0.26% achieved in ambient conditions.

Artificial photosynthesis in ambient conditions is much less efficient than the solar-to-biomass conversion (SBC) processes in nature. Here, we successfully mimic the NADP-mediated photosynthetic processes in green plants by introducing redox moieties as the electron acceptors in the present conjugated polymeric photocatalyst. The current artificial process substantially promotes the charge carrier separation efficiency and the oxygen reduction efficiency, achieving a photosynthesis rate for converting Earth-abundant water and oxygen in air into hydrogen peroxide as high as 909 µmol⋅g-1⋅h-1 and a solar-to-chemical conversion (SCC) efficiency up to 0.26%. The SCC efficiency is more than two times higher than the average SBC efficiency in nature (0.1%) and the highest value under ambient conditions. This study presents a strategy for efficient SCC in the future.

Identification of circRNA-miRNA-mRNA networks contributes to explore underlying pathogenesis and therapy strategy of gastric cancer.

BACKGROUND: Circular RNAs (circRNAs) are a new class of noncoding RNAs that have gained increased attention in human tumor research. However, the identification and function of circRNAs are largely unknown in the context of gastric cancer (GC). This study aims to identify novel circRNAs and determine their action networks in GC. METHODS: A comprehensive strategy of data mining, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and computational biology were conducted to discover novel circRNAs and to explore their potential mechanisms in GC. Promising therapeutic drugs for GC were determined by connectivity map (CMap) analysis. RESULTS: Six overlapped differentially expressed circRNAs (DECs) were screened from selected microarray and RNA-Seq datasets of GC, and the six DECs were then validated by sanger sequencing and RNase R treatment. Subsequent RT-qPCR analysis of GC samples confirmed decreased expressions of the six DECs (hsa_circ_0000390, hsa_circ_0000615, hsa_circ_0001438, hsa_circ_0002190, hsa_circ_0002449 and hsa_circ_0003120), all of which accumulated preferentially in the cytoplasm. MiRNA binding sites and AGO2 occupation of the six circRNAs were predicted using online databases, and circRNA-miRNA interactions including the six circRNAs and 33 miRNAs were determined. Then, 5320 target genes of the above 33 miRNAs and 1492 differently expressed genes (DEGs) from The Cancer Genome Atlas (TCGA) database were identified. After intersecting the miRNA target genes and the 889 downregulated DEGs, 320 overlapped target genes were acquired. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that these target genes were related to two critical tumor-associated signaling pathways. A protein-protein interaction network with the 320 target genes was constructed using STRING, and fifteen hubgenes (ATF3, BTG2, DUSP1, EGR1, FGF2, FOSB, GNAO1, GNAI1, GNAZ, GNG7, ITPR1, ITPKB, JUND, NR4A3, PRKCB) in the network were identified. Finally, bioactive chemicals (including vorinostat, trichostatin A and astemizole) based on the fifteen hubgenes were identifed as therapeutic agents for GC through the CMap analysis. CONCLUSIONS: This study provides a novel insight for further exploration of the pathogenesis and therapy of GC from the circRNA-miRNA-mRNA network perspective.

Highly efficient photosynthesis of hydrogen peroxide in ambient conditions.

Photosynthesis of hydrogen peroxide (H2O2) in ambient conditions remains neither cost effective nor environmentally friendly enough because of the rapid charge recombination. Here, a photocatalytic rate of as high as 114 µmol⋅g-1⋅h-1 for the production of H2O2 in pure water and open air is achieved by using a Z-scheme heterojunction, which outperforms almost all reported photocatalysts under the same conditions. An extensive study at the atomic level demonstrates that Z-scheme electron transfer is realized by improving the photoresponse of the oxidation semiconductor under visible light, when the difference between the Fermi levels of the two constituent semiconductors is not sufficiently large. Moreover, it is verified that a type II electron transfer pathway can be converted to the desired Z-scheme pathway by tuning the excitation wavelengths. This study demonstrates a feasible strategy for developing efficient Z-scheme photocatalysts by regulating photoresponses.

Valence-dependent catalytic activities of iron terpyridine complexes for pollutant degradation.

Herein, iron-terpyridine complexes with the iron centers at different initial valence states were utilized as homogeneous catalysts for the degradation of phenol in water. The iron(iii)-terpyridine complex induced the formation of more high-valent iron-oxo centers and hydroxyl radicals than the iron(ii)-terpyridine complex, leading to a higher catalytic activity.

Functional role of lncRNA LOC101927497 in N-methyl-N'-nitro-N-nitrosoguanidine-induced malignantly transformed human gastric epithelial cells.

AIMS: Evidence shows that aberrant expression of long non-coding RNA (lncRNA) is closely associated with tumor development and progression. However, the role of lncRNA in environmental carcinogen induced gastric tumorigenesis remains largely unknown. This study aimed at investigating the function role of lncRNA in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induce malignantly transformed human gastric epithelial cells. MAIN METHODS: In this study, high-throughput sequencing and qRT-PCR assay revealed marked downregulation of lncRNA LOC101927497 in the malignant transformed gastric epithelial cells induced by MNNG (GES-1-T cells), gain-of-function and loss-of-function assays showed that LOC101927497 can suppress the proliferation and migration of GES-1-T cells in vitro. RNA antisense purification experiment showed that LOC101927497 interacted with miR-574-5p in GES-1-T cells the most obvious. Further studies suggested that LOC101927497 may function as a tumor suppressor by interacting with miR-574-5p. KEY FINDINGS: LncRNA LOC101927497 functions as a suppressor by interacting with miR-574-5p, thus inhibiting the malignant phenotype of GES-1-T cells. SIGNIFICANCE: To the best of our knowledge, this is the first study to demonstrate the role of lncRNA in MNNG-induced gastric tumorigenesis, and it will provide new insights into the role of lncRNA in environmental carcinogen-induced gastric cancer.

[Hematologic toxicity of Gynura segetum and effects on vascular endothelium in a rat model of hepatic veno-occlusive disease].

OBJECTIVE: To observe the effects ofGynura segetum in rats with hepatic veno-occlusive disease (HVOD). METHODS: Sixty Sprague-Dawley rats were assigned to a blank control group, one of three Gynura segetum treatment groups (low-dose group, 5.0 g/kg; mid-dose group, 10 g/kg; high-dose group, 20 g/kg), or a pseudo-drug group (10 g/kg of pseudo-ginseng). After 28 days of treatment, effects on white blood cell count, coagulation, secreted factors from vascular endothelium, and histopathology of the spleen were observed and inter-group differences were statistically assessed. RESULTS: After the 4-week administration, all rats in the Gynura segetum treatment groups showed decrease in body weight, increases in numbers of leukocytes, neutrophils, lymphocytes, monocytes and eosinophils.decreases in platelets and platelet hematocrit, and increases in mean platelet volume and platelet distribution.In addition, the Gynura segetum treatments increased the prothrombin time, activated partial thromboplastin time, thrombin time, prothrombin ratio and international normalized ratio, but decreased the PT%, fibrinogen level and platelet aggregation.Serum levels of endothelin and nitric oxide were also elevated by the Gynura segetum treatments.All measured parameters showed significant differences from the control group (P less than 0.01 or less than 0.05).Finally, the splenic follicles were significantly reduced and the spleens showed an absence of germinal centers along with a large number of diffuse lymphocytes and reduced red pulp sinusoids. CONCLUSION: The Gynura segetum treatment has some toxic effects; it can reduce platelet count and platelet hematocrit, inhibit blood clotting time and platelet aggregation, increase the secretion of factors from the vascular endothelium and disrupt spleen histology.

Automatic clustering of flow cytometry data with density-based merging.

The ability of flow cytometry to allow fast single cell interrogation of a large number of cells has made this technology ubiquitous and indispensable in the clinical and laboratory setting. A current limit to the potential of this technology is the lack of automated tools for analyzing the resulting data. We describe methodology and software to automatically identify cell populations in flow cytometry data. Our approach advances the paradigm of manually gating sequential two-dimensional projections of the data to a procedure that automatically produces gates based on statistical theory. Our approach is nonparametric and can reproduce nonconvex subpopulations that are known to occur in flow cytometry samples, but which cannot be produced with current parametric model-based approaches. We illustrate the methodology with a sample of mouse spleen and peritoneal cavity cells.