Summary
Rice grain filling rate contributes largely to grain productivity and accumulation of nutrients. MicroRNAs (miRNAs) are key regulators of development and physiology in plants and become a ...novel key target for engineering grain size and crop yield. However, there is little studies, so far, showing the miRNA regulation of grain filling and rice yield, in consequence. Here, we show that suppressed expression of rice miR1432 (STTM1432) significantly improves grain weight by enhancing grain filling rate and leads to an increase in overall grain yield up to 17.14% in a field trial. Molecular analysis identified rice Acyl‐CoA thioesterase (OsACOT), which is conserved with ACOT13 in other species, as a major target of miR1432 by cleavage. Moreover, overexpression of miR1432‐resistant form of OsACOT (OXmACOT) resembled the STTM1432 plants, that is, a large margin of an increase in grain weight up to 46.69% through improving the grain filling rate. Further study indicated that OsACOT was involved in biosynthesis of medium‐chain fatty acids. In addition, RNA‐seq based transcriptomic analyses of transgenic plants with altered expression of miR1432 demonstrated that downstream genes of miR1432‐regulated network are involved in fatty acid metabolism and phytohormones biosynthesis and also overlap with the enrichment analysis of co‐expressed genes of OsACOT, which is consistent with the increased levels of auxin and abscisic acid in STTM1432 and OXmACOT plants. Overall, miR1432‐OsACOT module plays an important role in grain filling in rice, illustrating its capacity for engineering yield improvement in crops.
[B30]−: A Quasiplanar Chiral Boron Cluster Li, Wei-Li; Zhao, Ya-Fan; Hu, Han-Shi ...
Angewandte Chemie (International ed.),
May 26, 2014, Letnik:
53, Številka:
22
Journal Article
Recenzirano
Chirality is vital in chemistry. Its importance in atomic clusters has been recognized since the discovery of the first chiral fullerene, the D2 symmetric C76.1 A number of gold clusters have been ...found to be chiral,2 raising the possibility to use them as asymmetric catalysts. The discovery of clusters with enantiomeric structures is essential to design new chiral materials with tailored chemical and physical properties.3 Herein we report the first inherently chiral boron cluster of B30− in a joint photoelectron spectroscopy and theoretical study. The most stable structure of B30− is found to be quasiplanar with a hexagonal hole. Interestingly, a pair of enantiomers arising from different positions of the hexagonal hole are found to be degenerate in our global minimum searches and both should co‐exist experimentally because they have identical electronic structures and give rise to identical simulated photoelectron spectra.
Holey chiral: The B30− cluster was characterized by photoelectron spectroscopy and ab initio calculations. A pair of planar structures with a hexagonal hole at different positions are found to be degenerate with identical electronic structures. These two isomers are enantiomers, suggesting that B30− is the first chiral boron cluster.
A metal catalyst supported on an inert substrate could consist of both metal nanoparticles and singly dispersed metal atoms. Whether these singly dispersed metal atoms are active and how different ...their catalytic mechanism could be in contrast to a supported metal catalyst are fundamentally important for understanding catalysis on a supported metal or oxide. By taking reduction of NO with CO on singly dispersed Rh atoms anchored on an inert support SiO2 as a probe system (Rh1/SiO2), here we demonstrated how singly dispersed metal atoms on an inert support could perform a complex multi-step catalytic cycle through a mechanism distinctly different from that for a supported metal nanoparticle with continuously packed metal sites. These singly dispersed Rh1 atoms anchored on SiO2 are active in reducing nitric oxide with carbon monoxide through two reaction pathways that are different from those of Rh nanoparticles. In situ IR studies show that a CO molecule and a NO molecule coadsorb on a singly dispersed Rh atom, Rh1 anchored on SiO2, and couple to form an N atom to adsorb on the surface and a CO2 molecule to desorb. The adsorbed N atom further couples with another CO molecule in the gas phase to form an intermediate −NCO on Rh1; this intermediate can directly couple with an NO molecule adsorbed on the same Rh1 to form N2 and CO2. In another pathway, the adsorbed N atom can couple with a coadsorbed NO on the same Rh1 to form N2O; N2O further reacts with adsorbed CO on the same Rh1 to form N2 and CO2 through a high activation barrier that can be overcome at a high temperature. Our studies show that the singly dispersed metal atoms on an inert support have great potential to perform selective transformation of chemicals. The confirmed catalysis with a singly dispersed Rh1 on SiO2 through a mechanism different from a metal nanoparticle supported on the same substrate suggests the significance of taking the single-atom catalysis (SAC) into fundamental studies of catalysis of a supported metal catalyst, since metal nanoparticles and singly dispersed metal atoms likely coexist on the inert support of many supported catalysts.
Methanol synthesis from syngas (CO/CO2/H2) hydrogenation on the perfect Zn-terminated polar ZnO(0001) surface has been investigated using periodic density functional theory calculations. Our results ...show that direct CO2 hydrogenation to methanol is unlikely because, in the presence of surface atomic H and O, the highly stable formate (HCOO) and carbonate (CO3) readily produced from CO2 with low barriers of 0.11 and 0.09 eV will eventually accumulate and block the active sites of the ZnO(0001) surface. In contrast, methanol synthesis from CO hydrogenation is thermodynamically and kinetically feasible on the perfect ZnO(0001) surface. CO can be consecutively hydrogenated into formyl (HCO), formaldehyde (H2CO), and methoxy (H3CO) intermediates, leading to the final formation of methanol (H3COH). The reaction route via hydroxymethyl (H2COH) intermediate, a previously proposed species on the defective O-terminated ZnO(0001̅) surface, is kinetically inhibited on the perfect ZnO(0001) surface. The rate-determining step in the consecutive CO hydrogenation route is the hydrogenation of H3CO to H3COH. We also find that this final hydrogenation step is pronouncedly facilitated in the presence of water by lowering the activation barrier from 1.02 to 0.55 eV.
Learning burnout is a passive mental state among students. It is a common phenomenon that can cause many bad outcomes in Chinese medical students, such as mental disorders and suicide, and its causes ...are complex.
To analyze the relationship between alexithymia and learning burnout, as well as the mediating effect of mobile phone addiction, and provide clues for future interventions to deal with learning burnout among Chinese medical students.
In this cross-sectional study, convenience cluster sampling was used to produce a sample of 1200 medical universities in Chongqing, China. The Toronto Alexithymia Scale (TAS-20), Mobile Phone Addiction Tendency Scale (MPATS), and Learning Burnout Questionnaire (LBQ) were used to examine participants. Hierarchical regression was used to analyze the effect of alexithymia and mobile phone addiction on learning burnout. A structural equation model (SEM) with maximum likelihood was used to evaluate the mediating effect of mobile phone addiction on the relationship between alexithymia and learning burnout. The bootstrap method was used to confirm the significance of this mediating effect.
The final sample size was 1062, with a valid response rate of 88.5%. The prevalence of learning burnout among Chinese medical students was 39.6%. Results of hierarchical regression revealed that alexithymia (ΔR
=0.198, P<0.01) and mobile phone addiction (ΔR
=0.021, P<0.01) were independent factors of learning burnout; the SEM revealed that the mediating effect of mobile phone addiction between alexithymia and learning burnout accounted for 25.16% of the total effect of alexithymia on learning burnout; the bootstrap method revealed that the bounds of the CI did not contain 0, confirming the significance of this mediating effect.
Of the medical students, 39.6% had learning burnout. Alexithymia can positively predict learning burnout, and this relationship is partially mediated by mobile phone addiction.
Under the background of the accelerated aging of the population, comorbidity in the elderly has gradually become a social problem. At present, the related studies on chronic diseases are mainly ...focused on a single disease. This study aimed to investigate the prevalence of common chronic diseases, the conditions and patterns of comorbidity in middle-aged and elderly people in China.
We extracted the data from China Health and Retirement Longitudinal Study (CHARLS). A total of 14 diseases were included, and the prevalence was assessed by self-report. We calculate different disease combinations and perform descriptive statistics analysis of chronic disease and comorbidity status.
Among the 6754 subjects, 2833 (42.0%) people had at least one chronic disease, and 1138 (17.0%) people had two or more diseases at the same time. The top three diseases of prevalence were hypertension (15.4%), arthritis or rheumatism (11.0%), and stomach or digestive diseases (9.3%). Common dual disease combinations were hypertension and dyslipidemia, hypertension and arthritis or rheumatism, arthritis or rheumatism and stomach or digestive diseases.
Comorbidity is common in the population, and the pattern of chronic disease comorbidity is complex. Hypertension exists in a variety of comorbidity patterns, and its screening and prevention should be strengthened.
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•We developed a global minimum search program named TGMin.•TGMin program is based on the basin hopping algorithm with several improvements.•TGMin program is highly effecient in ...finding the global minima of nanoclusters.•An overview of recent improvements and applications of TGMin are presented.
Finding the global minima of nanoclusters is of great importance in cluster science and nanoscience. We have developed an efficient global minimum search program, named Tsinghua Global Minimum (TGMin, first released in 2012), based on the Basin-Hopping algorithm to find the global minima of nanoclusters, as well as periodic systems. We have recently made several improvements to the original Basin-Hopping algorithm, including a constrained perturbation function, a covalent-radius-based relaxation algorithm, an improved ultrafast shape recognition algorithm, and a planeness-check mechanism. The TGMin program has been successfully applied to search the global minima of a number of nanoclusters and periodic structures, including B30, B35, B36, B39, B40, CoB18−, RhB18−, MnB16−, and Au7 on the α-Al2O3(0001) surface. An overview of the TGMin code and several of its recent applications are presented here.
Health literacy (HL) is a risk factor for adverse outcomes in patients with cardiovascular disease, and shorter pre-hospital delay time is crucial for successful treatment of acute myocardial ...infraction (AMI) patients. Most previous studies focused on the influencing factors of pre-hospital delay but ignore the essential contribution of decision delay.
Therefore, the purpose of this study was to explore the effect of HL on decision delay.
Continuously included AMI patients admitted to a grade A class three hospital in Chongqing. HL level was assessed using Brief Health Literacy Screen and categorized as adequate or inadequate. Mann-Whitney
-test and Chi-square test were used to compare the differences between groups, and binary logistic regression was used to analyze the association between HL and decision delay.
A total of 217 AMI patients were enrolled in this study, including 166 males (76.5%) and 51 females (23.5%), with the median age was 68 years old; 135 (62.2%) patients had delayed decision-making while 82 (37.8%) did not; 157 (72.7%) patients had inadequate HL and 59 (27.3%) had adequate HL. The total HL score of non-delayed group was higher than that in delayed group (9.22 vs. 7.02,
< 0.000).
After adjusting for covariates, HL was significantly negatively associated with decision time. AMI patients with inadequate HL were more likely to delay seeking timely medical care.
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