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The confinement effect of carbon nanotubes plays a significant role in the field of catalysis. A bamboo-structured N-doped carbon nanotubes (NCNT) encapsulated PdCo nanoparticles (PdCo@NCNT) was prepared by pyrolysis method with melamine as carbon and nitrogen source. The preparation conditions of PdCo@NCNT and the growth mechanism of NCNT were studied. TEM test showed that the PdCo nanoparticles are fully encapsulated by the graphitic shell on the top of carbon nanotubes. There exists electron transfer between Pd and Co, and a bimetallic PdCo active center with electron-rich Pd and electron-deficient Co formed. PdCo@NCNT exhibited higher catalytic activity for furfural hydrogenation than Co@NCNT. PdCo@NCNT with PdCo encapsulated within NCNT showed better furfural hydrogenation activity and reusability property compared with PdCo/NCNT with NCNT external loading method. [ABSTRACT FROM AUTHOR]

Hydrogenation of furfural to furfuryl alcohol under H2 and N2 atmosphere was studied over zirconium phosphonate (ZrPO)‐supported PdCu (PdCu/ZrPO) catalysts. The direct hydrogenation and transfer hydrogenation activities of PdCu metal active sites and the transfer hydrogenation activity of Zr4+−O2− Lewis acid‐basic sites were investigated, respectively. The size and the distribution of Cu particles could be adjusted by altering the P/Zr molar ratio. Bimetallic PdCu could enhance the acidity of the PdCu/ZrPO catalysts, and improve the ratio of Lewis/Brønsted acid, which led to an increase in the transfer hydrogenation activity of Lewis acid‐basic pairs. The electronic effect between Pd and Cu promoted furfural to absorb onto electron‐deficient Cu through η1(O)‐aldehyde configuration, which contributed to the direct hydrogenation and the transfer hydrogenation at metal active sites. Especially, the adsorption and dissociation of H2 in electron‐rich Pd were promoted, which significantly improved the direct hydrogenation activity. [ABSTRACT FROM AUTHOR]

Background and Aims Vascular patterning is intimately related to plant form and function. Here, using barley (Hordeum vulgare) as a model, we studied the vascular anatomy of the spike-type inflorescence. The main aim of the present work was to clarify the relationship between rachis (spike axis) vasculature and spike size, to define vascular dynamics and to discuss the implications for transport capacity and its interaction with the spikelets. Methods We used serial transverse internode sections to determine the internode area, vascular area and number of veins along the rachis of several barley lines. Key Results Internode area and total vascular area show a clear positive correlation with spike size, whereas the number of veins is only weakly correlated. The lateral periphery of the rachis contains large mature veins of constant size, whereas the central part is occupied by small immature veins. Spikelet-derived veins entering the rachis often merge with the immature rachis veins but never merge with the mature veins. An increase in floret fertility through the conversion of a two-rowed barley into an isogenic six-rowed line, in addition to a decrease in floret fertility owing to enhanced pre-anthesis tip degeneration caused by the mutation tip sterile 2.b (tst2.b), significantly affected vein size but had limited to no effects on the number of veins or internode area. Conclusions The rachis vasculature is the result of a two-step process involving an initial layout followed by size adjustment according to floret fertility/spike size. The restriction of large mature vessels to the periphery and that of small immature vessels to the centre of the rachis suggests that long-distance transport and local supply to spikelets are spatially separated processes. The identification of spikelet-derived veins entering the rachis without fusing with its vasculature indicates that a vascular continuity between rachis and spikelets might be non-essential. [ABSTRACT FROM AUTHOR]

Two aliphatic diamine-bridged ferrocene ligands (C2-Fe-Ligand and C6-Fe-Ligand) were synthesized with aliphatic diamine and formylferrocene, and the corresponding bimetallic active site complexes (Ni-C2-Fe, Co-C2-Fe, and Ni-C6-Fe) were prepared to catalyze ethylene oligomerization. The ligands and the corresponding complexes were characterized by FTIR, 1H NMR, TG, ESI-MS, XRD, and SEM. The SEM results of the ligands confirmed that the length of the bridged group had an influence on the morphology, and an increase in the carbon length led to irregular short rods to the irregular flakes with a large size. The bimetallic complexes catalyzed efficiently ethylene oligomerization with MAO as co-catalyst, and these complexes produced C4 and C6 olefins. Ni-C2-Fe showed higher activity of 6.31 × 104 g·(mol Ni·h)−1 in cyclohexane at Al/Ni molar ratio of 700, temperature of 25 °C, and pressure of 0.5 MPa. Compared with single active site catalysts, the bimetallic active site catalysts had a higher selectivity for C4 olefin because of the competitive insertion of ethylene between different active centers. The modification of the metal center tuned the catalytic performance of the complexes in ethylene oligomerization. [ABSTRACT FROM AUTHOR]

Purpose: To investigate and compare the efficacy of amniotic membrane transplantation, corneal limbus stem cell conjunctival transplantation and pedicle conjunctival flap transposition in the treatment of pterygium., Methods: A total of 155 patients with pterygium were retrospectively analysed: 53 cases who received amniotic membrane transplantation, 41 who underwent corneal limbus stem cells conjunctival transplantation, and 63 patients who had pedicle conjunctival flap transposition., Results: Patients in the three groups had no significant differences in terms of age, times since surgery, or extent of pterygium extension onto the cornea (F:1.194, 0.639, 0.140 respectively; all P>0.05). A total of 137 out of 155 patients (88.4%) completed 6 months of follow up. The recurrence rates of pterygium for the three surgeries (amniotic membrane transplantation, corneal limbus stem cells conjunctival transplantation and pedicle conjunctival flap transposition) were 14.6%, 13.9% and 7.7%, respectively. No significant difference was identified when comparing the recurrence rate between any two groups (X2: 0.008, 1.211 and 0.890; P: 0.593, 0.218 and 0.276). Five patients presented with postoperative complications, including 3 cases of sub-conjunctival hemorrhage, 1 case of amniotic membrane dissolution, and 1 case of conjunctival cyst, accounting for 3.64% of all participants., Conclusion: These three surgical methods are equally effective in preventing the recurrence of pterygium after excision.