247 research outputs found

    Phosphorus-doped porous carbons as efficient electrocatalysts for oxygen reduction

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Efficient electrocatalysts for the oxygen reduction reaction (ORR) play a critical role in the performance of fuel cells and metal–air batteries. In this study, we report a facile synthesis of phosphorus (P)-doped porous carbon as a highly active electrocatalyst for the ORR. Phosphorus-doped porous carbon was prepared by simultaneous doping and activation of carbon with phosphoric acid (H3PO4) in the presence of Co. Both phosphorus and cobalt were found to play significant roles in improving the catalytic activity of carbon for the ORR. The as-prepared phosphorus-doped porous carbon exhibited considerable catalytic activity for the ORR as evidenced by rotating ring-disk electrode studies. At the same mass loading, the Tafel slope of phosphorus-doped porous carbon electrocatalysts is comparable to that of the commercial Pt/C catalysts (20 wt% Pt on Vulcan XC-72, Johnson Matthey) with stability superior to Pt/C in alkaline solutions

    High genetic abundance of Rpi-blb2/Mi-1.2/Cami gene family in Solanaceae

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    Relative genomic positions of genes among potato (upper), pepper (middle) and tomato (lower) along chromosome 6. (DOCX 282 kb

    Bond-Slip Behavior of Basalt Fiber Reinforced Polymer Bar in Concrete Subjected to Simulated Marine Environment: Effects of BFRP Bar Size, Corrosion Age, and Concrete Strength

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    Basalt Fiber Reinforced Polymer (BFRP) bars have bright potential application in concrete structures subjected to marine environment due to their superior corrosion resistance. Available literatures mainly focused on the mechanical properties of BFRP concrete structures, while the bond-slip behavior of BFRP bars, which is a key factor influencing the safety and service life of ocean concrete structures, has not been clarified yet. In this paper, effects of BFRP bars size, corrosion age, and concrete strength on the bond-slip behavior of BFRP bars in concrete cured in artificial seawater were investigated, and then an improved Bertero, Popov, and Eligehausen (BPE) model was employed to describe the bond-slip behavior of BFRP bars in concrete. The results indicated that the maximum bond stress and corresponding slip decreased gradually with the increase of corrosion age and size of BFRP bars, and ultimate slip also decreased sharply. The ascending segment of bond-slip curve tends to be more rigid and the descending segment tends to be softer after corrosion. A horizontal end in bond-slip curve indicates that the friction between BFRP bars and concrete decreased sharply

    Enhancing a Wnt-Telomere Feedback Loop Restores Intestinal Stem Cell Function in a Human Organotypic Model of Dyskeratosis Congenita

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    Patients with dyskeratosis congenita (DC) suffer from stem cell failure in highly proliferative tissues, including the intestinal epithelium. Few therapeutic options exist for this disorder, and patients are treated primarily with bone marrow transplantation to restore hematopoietic function. Here, we generate isogenic DC patient and disease allele-corrected intestinal tissue using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated gene correction in induced pluripotent stem cells and directed differentiation. We show that DC tissue has suboptimal Wnt pathway activity causing intestinal stem cell failure and that enhanced expression of the telomere-capping protein TRF2, a Wnt target gene, can alleviate DC phenotypes. Treatment with the clinically relevant Wnt agonists LiCl or CHIR99021 restored TRF2 expression and reversed gastrointestinal DC phenotypes, including organoid formation in vitro, and maturation of intestinal tissue and xenografted organoids in vivo. Thus, the isogenic DC cell model provides a platform for therapeutic discovery and identifies Wnt modulation as a potential strategy for treatment of DC patients
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