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We present a stepwise optimal genome halving algorithm designed for large eukaryote genomes with largely single-copy genes, taking advantage of a signature pattern of paralog distribution in ancient polyploids. This is applied to the genome of Nelumbo nucifera, the sacred lotus, which is the descendant of a duplicated basal eudicot genome. In concert with the reconstructed ancestor of the grape, we investigate early events in eudicot evolution and show that the chromosome number of the common ancestor of lotus and grape was likely between 5 and 7. We show that the duplication of the ancestor of lotus and the triplication of the ancestor of grape were not closely preceded by any additional such event before the divergence of their two lineages. 相似文献
95.
This paper gives lower estimates for the frequency modules of almost periodic solutions to equations of the form
, where A generates a strongly continuous semigroup in a Banach space
, F(t,x) is 2π-periodic in t and continuous in (t,x), and f is almost periodic. We show that the frequency module ℳ(u) of any almost periodic mild solution u of (*) and the frequency module ℳ(f) of f satisfy the estimate e
2π
iℳ(f)⊂e
2π
iℳ(u). If F is independent of t, then the estimate can be improved: ℳ(f)⊂ℳ(u). Applications to the nonexistence of quasi-periodic solutions are also given. 相似文献
96.
97.
Wenbo Dong Zhiying Qin Kuixing Wang Yueyuan Xiao Xiangyang Liu Shijie Ren Longyu Li 《Angewandte Chemie (International ed. in English)》2023,62(5):e202216073
Imine-linked covalent organic frameworks (COFs) have been extensively studied in photocatalysis because of their easy synthesis and excellent crystallinity. The effect of imine-bond orientation on the photocatalytic properties of COFs, however, is still rarely studied. Herein, we report two novel COFs with different orientations of imine bonds using oligo(phenylenevinylene) moieties. The COFs showed similar structures but great differences in their photoelectric properties. COF-932 demonstrated a superior hydrogen evolution performance compared to COF-923 when triethanolamine was used as the sacrificial agent. Interestingly, the use of ascorbic acid led to the protonation of the COFs, further altering the direction of electron transfer. The photocatalytic performances were increased to 23.4 and 0.73 mmol g−1 h−1 for protonated COF-923 and COF-932, respectively. This study provides a clear strategy for the design of imine-linked COF-based photocatalysts and advances the development of COFs. 相似文献
98.
Dr. Liping Liu Dr. Haibing Meng Dr. Yongqiang Chai Dr. Xianjie Chen Dr. Jingyi Xu Dr. Xiaolong Liu Dr. Weixu Liu Prof. Dirk M. Guldi Prof. Yongfa Zhu 《Angewandte Chemie (International ed. in English)》2023,62(11):e202217897
High-efficiency photocatalysts based on metal-organic frameworks (MOFs) are often limited by poor charge separation and slow charge-transfer kinetics. Herein, a novel MOF photocatalyst is successfully constructed by encapsulating C60 into a nano-sized zirconium-based MOF, NU-901. By virtue of host-guest interactions and uneven charge distribution, a substantial electrostatic potential difference is set-up in C60@NU-901. The direct consequence is a robust built-in electric field, which tends to be 10.7 times higher in C60@NU-901 than that found in NU-901. In the catalyst, photogenerated charge carriers are efficiently separated and transported to the surface. For example, photocatalytic hydrogen evolution reaches 22.3 mmol g−1 h−1 for C60@NU-901, which is among the highest values for MOFs. Our concept of enhancing charge separation by harnessing host-guest interactions constitutes a promising strategy to design photocatalysts for efficient solar-to-chemical energy conversion. 相似文献
99.
Kuixing Wang Yuelin Zhong Wenbo Dong Yueyuan Xiao Prof. Shijie Ren Prof. Longyu Li 《Angewandte Chemie (International ed. in English)》2023,62(30):e202304611
Covalent organic frameworks (COFs) have gained significant attention as key photocatalysts for efficient solar light conversion into hydrogen production. Unfortunately, the harsh synthetic conditions and intricate growth process required to obtain highly crystalline COFs greatly hinder their practical application. Herein, we report a simple strategy for the efficient crystallization of 2D COFs based on the intermediate formation of hexagonal macrocycles. Mechanistic investigation suggests that the use of 2,4,6-triformyl resorcinol (TFR) as the asymmetrical aldehyde build block allows the equilibration between irreversible enol-to-keto tautomerization and dynamic imine bonds to produce the hexagonal β-ketoenamine-linked macrocycles, the formation of which could provide COFs with high crystallinity in half hour. We show that COF-935 with 3 wt % Pt as cocatalyst exhibit a high hydrogen evolution rate of 67.55 mmol g−1 h−1 for water splitting when exposed to visible light. More importantly, COF-935 exhibits an average hydrogen evolution rate of 19.80 mmol g−1 h−1 even at a low loading of only 0.1 wt % Pt, which is a significant breakthrough in this field. This strategy would provide valuable insights into the design of highly crystalline COFs as efficient organic semiconductor photocatalysts. 相似文献
100.
Xiaofang Bai Xiuping Zhang Yujiao Sun Mingcheng Huang Prof. Dr. Jiantao Fan Prof. Dr. Shaoyi Xu Prof. Dr. Hui Li 《Angewandte Chemie (International ed. in English)》2023,62(38):e202308704
To date, only a few noble metal oxides exhibit the required efficiency and stability as oxygen evolution reaction (OER) catalysts under the acidic, high-voltage conditions that exist during proton exchange membrane water electrolysis (PEMWE). The high cost and scarcity of these catalysts hinder the large-scale application of PEMWE. Here, we report a novel OER electrocatalyst for OER comprised of uniformly dispersed Ru clusters confined on boron carbon nitride (BCN) support. Compared to RuO2, our BCN-supported catalyst shows enhanced charge transfer. It displays a low overpotential of 164 mV at a current density of 10 mA cm−2, suggesting its excellent OER catalytic activity. This catalyst was able to operate continuously for over 12 h under acidic conditions, whereas RuO2 without any support fails in 1 h. Density functional theory (DFT) calculations confirm that the interaction between the N on BCN support and Ru clusters changes the adsorption capacity and reduces the OER energy barrier, which increases the electrocatalytic activity of Ru. 相似文献