Synthesis and optical properties of composite films from P3HT and sandwich-like Ag-C-Ag nanoparticles

This document is the Accepted Manuscript of the following article: Lingpeng Yan, Yamin Hao, Xiaoting Feng, Yongzhen Yang, Xuguang Liu, Yongkang Chen, and Bingshe Xu, ‘Synthesis and optical properties of composite films from P3HT and sandwich-like Ag–C–Ag nanoparticles’, RSC Advances, Vol. 5(97): 79860-79867, 2015, DOI: https://doi.org/10.1039/C5RA16854F. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Sandwich-like Ag-C-Ag nanoparticles (Ag-C-Ag NPs) were synthesized under mild hydrothermal conditions in a one-step method. With this approach, Ag was not only encapsulated in the centre of an individual carbon nanosphere, but was also uniformly dispersed within the carbon matrix up to the sphere's shell. Then, poly(3-hexylthiophene):Ag-C-Ag NPs (P3HT:Ag-C-Ag NPs) composite films were prepared by a spin coating method with a chlorobenzene solution of Ag-C-Ag NPs and P3HT. Both morphology and microstructure of Ag-C-Ag NPs were investigated by field emission scanning electron microscopy and high resolution transmission electron microscopy. The possible formation mechanism was proposed. The results have indicated that the Ag-C-Ag NPs present many functional groups and their energy levels match with those of P3HT. It has been observed that an introduction of Ag-C-Ag NPs to P3HT can induce broad and high-absorbing spectra as well as great photoluminescence quenching of P3HT. It is evident that sandwich-like Ag-C-Ag NPs have a great potential to be a new acceptor material in photovoltaic devices.Peer reviewe

Antenna arrangement and energy-transfer pathways of PSI-LHCI from the moss Physcomitrella patens

Plants harvest light energy utilized for photosynthesis by light-harvesting complex I and II (LHCI and LHCII) surrounding photosystem I and II (PSI and PSII), respectively. During the evolution of green plants, moss is at an evolutionarily intermediate position from aquatic photosynthetic organisms to land plants, being the first photosynthetic organisms that landed. Here, we report the structure of the PSI-LHCI supercomplex from the moss Physcomitrella patens (Pp) at 3.23 angstrom resolution solved by cryo-electron microscopy. Our structure revealed that four Lhca subunits are associated with the PSI core in an order of Lhca1-Lhca5-Lhca2-Lhca3. This number is much decreased from 8 to 10, the number of subunits in most green algal PSI-LHCI, but the same as those of land plants. Although Pp PSI-LHCI has a similar structure as PSI-LHCI of land plants, it has Lhca5, instead of Lhca4, in the second position of Lhca, and several differences were found in the arrangement of chlorophylls among green algal, moss, and land plant PSI-LHCI. One chlorophyll, PsaF-Chl 305, which is found in the moss PSI-LHCI, is located at the gap region between the two middle Lhca subunits and the PSI core, and therefore may make the excitation energy transfer from LHCI to the core more efficient than that of land plants. On the other hand, energy-transfer paths at the two side Lhca subunits are relatively conserved. These results provide a structural basis for unravelling the mechanisms of light-energy harvesting and transfer in the moss PSI-LHCI, as well as important clues on the changes of PSI-LHCI after landing

Salidroside Ameliorates Renal Interstitial Fibrosis by Inhibiting the TLR4/NF-κB and MAPK Signaling Pathways

Salidroside (Sal) is an active ingredient that is isolated from Rhodiola rosea, which has been reported to have anti-inflammatory activities and a renal protective effect. However, the role of Sal on renal fibrosis has not yet been elucidated. Here, the purpose of the current study is to test the protective effects of Sal against renal interstitial fibrosis (RIF), and to explore the underlying mechanisms using both in vivo and in vitro models. In this study, we establish the unilateral ureteric obstruction (UUO) or folic acid (FA)-induced mice renal interstitial fibrosis in vivo and the transforming growth factor (TGF)-β1-stimulated human proximal tubular epithelial cell (HK-2) model in vitro. The levels of kidney functional parameters and inflammatory cytokines in serum are examined. The degree of renal damage and fibrosis is determined by histological assessment. Immunohistochemistry and western blotting are used to determine the mechanisms of Sal against RIF. Our results show that treatment with Sal can ameliorate tubular injury and deposition of the extracellular matrix (ECM) components (including collagen Ш and collagen I). Furthermore, Sal administration significantly suppresses epithelial-mesenchymal transition (EMT), as evidenced by a decreased expression of α-SMA, vimentin, TGF-β1, snail, slug, and a largely restored expression of E-cadherin. Additionally, Sal also reduces the levels of serum biochemical markers (serum creatinine, Scr; blood urea nitrogen, BUN; and uric acid, UA) and decreases the release of inflammatory cytokines (IL-1β, IL-6, TNF-α). Further study revealed that the effect of Sal on renal interstitial fibrosis is associated with the lower expression of TLR4, p-IκBα, p-NF-κB and mitogen-activated protein kinases (MAPK), both in vivo and in vitro. In conclusion, Sal treatment improves kidney function, ameliorates the deposition of the ECM components and relieves the protein levels of EMT markers in mouse kidneys and HK-2 cells. Furthermore, Sal treatment significantly decreases the release of inflammatory cytokines and inhibits the TLR4/NF-κB and MAPK signaling pathways. Collectively, these results suggest that the administration of Sal could be a novel therapeutic strategy in treating renal fibrosis

P3HT/Dodecylamine Functioned Carbon Microspheres Composite Films for Polymer Solar Cells

P3HT/dodecylamine functioned carbon microspheres (D-CMSs) composite films were prepared by spin-coating method with D-CMSs and P3HT mixture chloroform solution, and the photovoltaic devices with structures ITO/PEDOT:PASS/P3HT:D-CMSs/Al were also fabricated. Morphology and structure of the composite films were characterized by field emission scanning electron microscopy, atomic force microscopy, Fourier transformation infrared spectrometry and X-raydiffractometry. Ultraviolet-visible spectrophotometry and photoluminescence spectrometry were used to characterize the optical property of the composite films. The results show that composite films with 1:1 ratio of D-CMSs to P3HT had optimum morphology and optical performance. The absorption of annealed P3HT:D-CMSs composite films was enhanced with a red-shift, and the crystallinity of film enhanced after annealing. The polymer solar cells based on P3HT:D-CMSs composite films exhibited a high Voc of 0.840 V, suggesting D-CMSs is a promising acceptor for polymer cells. This would lay an experimental and theoretical foundation for further researching the fabricating polymer solar cells with new acceptors

A Contrastive Framework for Neural Text Generation

Text generation is of great importance to many natural language processing applications. However, maximization-based decoding methods (e.g. beam search) of neural language models often lead to degenerate solutions -- the generated text is unnatural and contains undesirable repetitions. Existing approaches introduce stochasticity via sampling or modify training objectives to decrease probabilities of certain tokens (e.g., unlikelihood training). However, they often lead to solutions that lack coherence. In this work, we show that an underlying reason for model degeneration is the anisotropic distribution of token representations. We present a contrastive solution: (i) SimCTG, a contrastive training objective to calibrate the model's representation space, and (ii) a decoding method -- contrastive search -- to encourage diversity while maintaining coherence in the generated text. Extensive experiments and analyses on three benchmarks from two languages demonstrate that our proposed approach outperforms state-of-the-art text generation methods as evaluated by both human and automatic metrics.Comment: 22 pages, 8 figures, and 10 tables (v2 adds some experimental results

Linkage and sequence analysis of neutral oligosaccharides by negative-ion MALDI tandem mass spectrometry with laser-induced dissociation

Mass spectrometry (MS) has become the primary method for high-sensitivity structural determination of oligosaccharides. Fragmentation in the negative-ion MS can provide a wealth of structural information and these can be used for sequence determination. However, although negative-ion MS of neutral oligosaccharide using the deprotonated molecule [M-H](-) as the precursor has been very successful for electrospray ionization (ESI), it has only limited success for matrix-assisted laser desorption/ionization (MALDI). In the present study, the features of negative-ion MALDI primary spectra were investigated in detail and the product-ion spectra using [M-H](-) and [M+Cl](-) as the precursors were carefully compared. The formation of [M-H](- )was the main difficulty for MALDI while [M+Cl](-) was proved to be useful as alternative precursor anion for MALDI-MS/MS to produce similar fragmentation for sequencing of neutral oligosaccharides. N-(1-naphthyl)ethylenediamine dihydrochloride was then used as both the matrix and the Cl- dopant to evaluate the extent of structural information that can be obtained by negative-ion fragmentation from [M+Cl](-) using laser-induced dissociation (LID)-MS/MS for linkage assignment of gluco-oligosaccharides and for typing of blood-group ABO(H) and Lewis antigens on either type 1 or type 2 backbone-chains. (C) 2019 Elsevier B.V. All rights reserved

Fluorescent carbon quantum dots synthesized by chemical vapor deposition: : An alternative candidate for electron acceptor in polymer solar cells

Excitation-wavelength-dependent blue-greenish fluorescent carbon quantum dots (CQDs) with graphite structure were synthesized by chemical vapor deposition (CVD) method. In comparison with those synthesized by hydrothermal method (named H-CQDs), C-CQDs have less hydrophilic terminal groups, showing good solubility in common organic solvents. Furthermore, these synthesized C-CQDs show a low LUMO energy level (LUMO = −3.84 eV), which is close to that of phenyl-C61-butyric acid methyl ester (PC61BM, LUMO = −4.01 eV), the most widely used electron acceptor in polymer solar cells. Photoluminescence quenching of the poly(3-hexylthiophene-2,5-diyl):C-CQDs blended film (P3HT:C-CQDs) indicated that a photo-induced charge transfer between P3HT and C-CQDs occurs in such a composite film. Bulk heterojunction solar cells using C-CQDs as electron acceptors or doping materials were fabricated and tested. High fill factors were achieved for these C-CQDs based polymer solar cells, demonstrating that CQDs synthesized by CVD could be alternative to the fullerene derivatives for applying in polymer solar cells.Peer reviewe