Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
Not a member yet
3266 research outputs found
Sort by
Improved photovoltaic performance of D-A-D-type small molecules with isoindigo and pyrene units by inserting different pi-conjugated bridge
No full textTwo novel D-pi-A-pi-D-type small molecules (SMs) of IID(Ac-Py)(2) and IID(Th-Py)(2) were synthesized and characterized, in which isoindigo (IID), acetylene (Ac) or thiophene (Th), and pyrene (Py) were used as the acceptor (A) core, extended pi-bridges, and donor (D) terminal units, respectively. Significantly improved photophysical and photovoltaic performances were observed for both SMs containing extended pi-bridge in comparison with those for their parent D-A-D type molecule of IID(Py)(2). Compared to IID(Ac-Py)(2), IID(Th-Py)(2) shows a better photovoltaic performance due to broader absorption, deeper HOMO levels (-5.44 eV) and better morphology of the devices. A maximum power conversion efficiency (PCE) of 1.88% with a short-circuit current density Usc) of 6.90 mA cm(-2) was obtained in the IID(Th-Py)(2)/PC71BM-based solar cells, which is 235 times the value of IID(Ac-Py)(2)-based cells. Particularly, the IID(Th-Py)(2)/PC61BM-based device exhibited a Vac value up to 1.01 V, which is 0.27 V and 0.12 V higher than IID(Py)(2)/and IlD(Ac-Py)(2)/PC61BM-based devices, respectively. To our best knowledge, the Vac of 1.01 V is among the highest values in literature for solution processed SMs OSCs without any post processing. (C) 2016 Published by Elsevier Ltd
Good Low-Temperature Properties of Nitrogen-Enriched Porous Carbon as Sulfur Hosts for High-Performance Li-S Batteries
No full textDespite the increased attention devoted to exploring cathode construction based on various nitrogen enriched carbon scaffolds at room temperature, the low temperature behaviors of Li-S cathodes have yet to be studied. Herein, we demonstrate the good low-temperature electrochemical performances of nitrogen-enriched carbon/sulfur composite cathodes. Electrochemical evaluation indicates that a reversible capacity of 368 mAh g(-1) (0.5 C) over 100 cycles is achieved at -20 degrees C. After returning to 25 degrees C, a capacity of 620 mAh g(-1) (0.5 C) is achieved over 350 cycles with a low-capacity attenuation rate (0.071% per cycle) and an initial capacity of 1151 mAh g(-1) (0.1C). This positive electrochemical property was speculated to result from the good surface chemistry of the various amine groups in the nitrogen-enriched carbon materials with enhanced polysulfide immobilization
Synthesis and Evaluation of Microspherical Li1.2Mn0.54Co0.13Ni0.13O2 through Carbon Dioxides-assisted Co-precipitation Method for Lithium-ion Battery
No full textLithium-rich layered electrode materials are of interest as a promising candidate of cathodes for lithiumion batteries because of their excellent electrochemical properties. The electrochemical performance of these materials is mainly regulated by preparation conditions during synthesis and calcination process. Here, microspherical Li1.2Mn0.54Co0.13Ni0.13O2 (LMNCO) particles are synthesized through steady pH value control with carbon dioxides bubbling method in co-precipitation process using a simple reactor. SEM images present that CP-LMNCO sample prepared through the assistance of carbon dioxides has spherical particle morphology, while sample (TP-LMNCO) without carbon dioxides assistance shows large nanoparticles agglomeration. The CP-LMNCO electrode demonstrates superior electrochemical performance, which exhibits capacity retention of 97.76% after 100 cycles compared with only 81.94% for TP-LMNCO electrode at 1C (250mAg(-1)). Even at a higher current density (5C), the CP-LMNCO electrode shows reversible capacity up to 105.4mA h g(-1). The remarkably improved electrochemical performance of CP-LMNCO electrode is ascribed to spherical morphology with small surface area which decreases side reactions with electrolyte during cycling and smaller primary sizes which reduce lithium ion (Li+) diffusion distance. Furthermore, the synthesis of spherical materials using metal sulfate with high concentration (up to 5M) as starting agents are attempted under carbon dioxides assisted conditions, and as-prepared materials also show improved performance. (C) 2016 Elsevier Ltd. All rights reserved
Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods
No full textIn this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO -mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. (C) 2016 Elsevier Ltd. All rights reserved
Alkoxyl Side Chain Substituted Thieno[3,4-c]pyrrole-4,6-dione To Enhance Photovoltaic Performance with Low Steric Hindrance and High Dipole Moment
No full textA series of N-OR substituted thieno[3,4-c]pyrrole-4,6-dione (TPD) and benzo[1,2-b:4,5-b']dithiophene (BDT) based copolymers are systematically investigated. The replacing CH2 with smaller size oxygen atom not only reduces the steric hindrance but also enhances the dipole moment (Delta mu(ge)), which is in favor of charge separation. while the optical and electrochemical properties almost remain unchanged due to the alkoxyl chain on TPD unit not conjugated with the backbone. Consequently, the PBT-O8 based solar cell devices yield a remarkable short-circuit current density (J(SC)) of up to 14.3 mA/cm(2) and power conversion efficiency (PCE) of 8.22%, which exhibits an increase of 10% in comparison with that of PBT-C8 (PCE 7.50%). Furthermore, the PCEs increase almost linearly with decreasing side chain length from 012 to 010 to 08. Apart from the novel TPD analogues reported here, this work also provides a new insight into the ingenious use of alkoxyl side chain to improve the photovoltaic performance
Irregular xylem 7 (IRX7) is required for anchoring seed coat mucilage in Arabidopsis
No full textLarge quantities of mucilage are synthesized in seed coat epidermis cells during seed coat differentiation. This process is an ideal model system for the study of plant cell wall biosynthesis and modifications. In this study, we show that mutation in Irregular Xylem 7 (IRX7) results in a defect in mucilage adherence due to reduced xylan biosynthesis. IRX7 was expressed in the seeds from 4 days post-anthesis (DPA) to 13 DPA, with the peak of expression at 13 DPA. The seed coat epidermis cells of irx7 displayed no aberrant morphology during differentiation, and these cells synthesized and deposited the same amount of mucilage as did wild type (WT) cells. However, the distribution of the water-soluble vs. adherent mucilage layers was significantly altered in irx7 compared to the WT. Both the amount of xylose and the extent of glycosyl linkages of xylan was dramatically decreased in irx7 water-soluble and adherent mucilage compared to the WT. The polymeric structure of water-soluble mucilage was altered in irx7, with a total loss of the higher molecular weight polymer components present in the WT. Correspondingly, whole-seed immunolabeling assays and dot-immunoassays of extracted mucilage indicated dramatic changes in rhamnogalacturonan I (RG I) and xylan epitopes in irx7 mucilage. Furthermore, the crystalline cellulose content was significantly reduced in irx7 mucilage. Taken together, these results indicate that xylan synthesized by IRX7 plays an essential role in maintaining the adhesive property of seed coat mucilage, and its structural role is potentially implemented through its interaction with cellulose
Identification of an itaconic acid degrading pathway in itaconic acid producing Aspergillus terreus
No full text<p>
Itaconic acid, one of the most promising and flexible bio-based chemicals, is mainly produced by Aspergillus terreus. Previous studies to improve itaconic acid production in A. terreus through metabolic engineering were mainly focused on its biosynthesis pathway, while the itaconic acid-degrading pathway has largely been ignored. In this study, we used transcriptomic, proteomic, bioinformatic, and in vitro enzymatic analyses to identify three key enzymes, itaconyl-CoA transferase (IctA), itaconyl-CoA hydratase (IchA), and citramalyl-CoA lyase (CclA), that are involved in the catabolic pathway of itaconic acid in A. terreus. In the itaconic acid catabolic pathway in A. terreus, itaconic acid is first converted by IctA into itaconyl-CoA with succinyl-CoA as the CoA donor, and then itaconyl-CoA is hydrated into citramalyl-CoA by IchA. Finally, citramalyl-CoA is cleaved into acetyl-CoA and pyruvate by CclA. Moreover, IctA can also catalyze the reaction between citramalyl-CoA and succinate to generate succinyl-CoA and citramalate. These results, for the first time, identify the three key enzymes, IctA, IchA, and CclA, involved in the itaconic acid degrading pathway in itaconic acid producing A. terreus. The results will facilitate the improvement of itaconic acid production by metabolically engineering the catabolic pathway of itaconic acid in A. terreus.</p
Selective and Full Derivatization of Amino Group in Chitosan with Alkyl Chloroformate of Low Stereo-Hindrance
No full textHigh-specificity synthesis of novel monomers by remodeled alcohol hydroxylase
No full textBackground: Diols are important monomers for the production of plastics and polyurethanes, which are widely used in our daily life. The medium-chain diols with one hydroxyl group at its subterminal end are able to confer more flexibility upon the synthesized materials. But unfortunately, this type of diols has not been synthesized so far. The strong need for advanced materials impelled us to develop a new strategy for the production of these novel diols. In this study, we use the remodeled P450(BM3) for high-specificity production of 1,7-decanediol
Putative methyltransferase LaeA and transcription factor CreA are necessary for proper asexual development and controlling secondary metabolic gene cluster expression
No full textThe morphological development of fungi is a complex process and is often coupled with secondary metabolite production. In this study, we assessed the function of putative methyltransferase LaeA and transcription factor CreA in controlling asexual development and secondary metabolic gene cluster expression in Penicillium oxalicum. The deletion of laeA (Delta laeA) impaired the conidiation in P. oxalicum, with a downregulated expression of brlA. Overexpression of P. oxalicum brlA in Delta laeA could upregulate brlA and abaA remarkably, but could not rescue the conidiation defect; therefore, brlA and abaA expression were necessary but not sufficient for conidiation. Deletion of creA in Delta laeA background (Delta laeA Delta creA) blocked conidiation with a white fluffy phenotype. Nutrient-rich medium could not rescue developmental defects in Delta laeA Delta creA mutant but could rescue defects in Delta laeA. Expression of 10 genes, namely, albA/wA, abrB/yA, arpA, aygA, arpA-like, arpB, arpB-like, rodA, rodA-like, and rodB, for pigmentation and spore wall protein genes was silenced in Delta laeA Delta creA, whereas only six of them were downregulated in Delta laeA. Among the 28 secondary metabolism gene clusters in P. oxalicum, four secondary metabolism gene clusters were silenced in Delta laeA and two were also silenced in Delta brlA mutant. A total of 10 physically linked and coregulated genes were distributed over five chromosomes in Delta laeA. Six of these genes were located in subtelomeric regions, thus demonstrating a positional bias for LaeA-regulated clusters toward subtelomeric regions. All of silenced clusters located in subtelomeric regions were derepressed in Delta laeA Delta creA, hence showing that lack of CreA could remediate the repression of gene clusters in Delta laeA background. Results show that both putative methyltransferase LaeA and transcription factor CreA are necessary for proper asexual development and controlling secondary metabolic gene cluster expression. (C) 2016 Elsevier Inc. All rights reserved