The 3d transition metal-catalyzed enantioconvergent radical cross-coupling provides a powerful tool for chiral molecule synthesis. In the classic mechanism, the bond formation relies on the ...interaction between nucleophile-sequestered metal complexes and radicals, limiting the nucleophile scope to sterically uncongested ones. The coupling of sterically congested nucleophiles poses a significant challenge due to difficulties in transmetalation, restricting the reaction generality. Here, we describe a probable outer-sphere nucleophilic attack mechanism that circumvents the challenging transmetalation associated with sterically congested nucleophiles. This strategy enables a general copper-catalyzed enantioconvergent radical N-alkylation of aromatic amines with secondary/tertiary alkyl halides and exhibits catalyst-controlled stereoselectivity. It accommodates diverse aromatic amines, especially bulky secondary and primary ones to deliver value-added chiral amines (>110 examples). It is expected to inspire the coupling of more nucleophiles, particularly challenging sterically congested ones, and accelerate reaction generality.
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IJS, KILJ, NUK, PNG, UL, UM
Quantum networks will enable extraordinary capabilities for communicating and processing quantum information. These networks require a reliable means of storage, retrieval, and manipulation of ...quantum states at the network nodes. A node receives one or more coherent inputs and sends a conditional output to the next cascaded node in the network through a quantum channel. Here, we demonstrate this basic functionality by using the quantum interference mechanism of electromagnetically induced transparency in a transmon qubit coupled to a superconducting resonator. First, we apply a microwave bias, i.e., drive, to the qubit-cavity system to prepare a Λ-type three-level system of polariton states. Second, we input two interchangeable microwave signals, i.e., a probe tone and a control tone, and observe that transmission of the probe tone is conditional upon the presence of the control tone that switches the state of the device with up to 99.73% transmission extinction. Importantly, our electromagnetically induced transparency scheme uses all dipole allowed transitions. We infer high dark state preparation fidelities of >99.39% and negative group velocities of up to -0.52±0.09 km/s based on our data.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
The purpose of this study was to investigate the prevalence and epidemiological characteristics of late-onset hypogonadism (LOH) in middle-aged and elderly Chinese men. Two cross-sectional studies ...were conducted at 5-year intervals in community-dwelling men living in the same area. A total of 1472 (Study 1, S1) and 944 (Study 2, S2) men aged 40–69 years old were recruited as subjects. Subjects were evaluated through combining serum reproductive hormone levels with the Androgen Deficiency in Aging Males (ADAM) questionnaire and the Aging Males’ Symptoms (AMS) scale. A significant difference was found in mean testosterone deficiency (TD) prevalence between S1 and S2, using either serum total testosterone (TT; 14.02% vs. 6.36%) or serum calculated free testosterone (cFT; 43.69% vs. 16.53%) cutoff values. According to the S1 or S2 data, the mean prevalence of LOH was 37.85%/15.47% in the positive ADAM test and 15.42%/9.43% in the positive AMS test (p < .01). According to classifications of TD based on gonadal status, the prevalence of secondary TD (27.34%) was higher than the primary (16.36%) and compensated (15.42%) TD in S1 (p < .01). However, there were significant differences among the prevalence of primary (6.89%), secondary (9.64%), and compensated (27.65%) TD in S2 (p < .05). Different types of testosterone levels, TD cutoff values, and questionnaires influenced the prevalence of TD and LOH. The serum FT cutoff value was an optimal threshold for evaluating and diagnosing TD and LOH, whose prevalence increased gradually with male aging.
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•An integrated strategy of cell metabolomics and plasma metabolomics was adopted to clarify the potential mechanism of the hypouricemic effect of Inonotus hispidus for the first ...time.•Inonotus hispidus may inhibit uric acid synthesis by regulating a variety of metabolic pathways.•The results highlight Inonotus hispidus as an effective adjunct in the treatment of hyperuricemia.
As an easy recurrent metabolic disease, hyperuricemia affected the life quality of patients seriously. Inonotus hispidus is a kind of edible and medicinal fungi with hypouricemic effect. However, the mechanism remains unclear. In this study, cell metabolomics integrated with serum metabolomics were carried out to explore the potential mechanism of Inonotus hispidus in the treatment of hyperuricemia. The results indicate that the potential regulatory mechanism was mainly related to amino acid metabolism and glycerophospholipid metabolism, involving the regulation of 27 metabolites, including 12 in HHL-5 human primary hepatocytes and 15 in mouse plasma. Inonotus hispidus may show efficacy by regulating the synthesis of uric acid, and the fungi can also regulate the lipid disturbances caused by hyperuricemia. This work elucidated potential biomarkers and mechanisms of action in the hypouricemic effect of Inonotus hispidus from the perspective of endogenous metabolites, which provides a scientific basis for its further development and application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Type 2 diabetes (T2DM) as a non-communicable disease imposes heavy disease burdens on society. Limited studies have been conducted to assess the effects of short-term air pollution exposure on T2DM, ...especially in Asian regions. Our research aimed to determine the association between short-term exposure to ambient nitrogen dioxide (NO2) and outpatient visits for T2DM in Chongqing, the largest city in western China, based on the data collected from November 28, 2013 to December 31, 2019. A generalized additive model (GAM) was applied, and stratified analyses were performed to investigate the potential modifying effects by age, gender, and season. Meanwhile, the disease burden was revealed from attributable risk. Positive associations between short-term NO2 and daily T2DM outpatient visits were observed. The strongest association was observed at lag 04, with per 10 μg/m3 increase of NO2 corresponded to increased T2DM outpatient visits at 1.57% 95% confidence interval (CI): 0.48%, 2.65%. Stronger associations were presented in middle-aged group (35–64 years old), male group, and cool seasons (October to March). Moreover, there were 1.553% (8664.535 cases) of T2DM outpatient visits attributable to NO2. Middle-aged adults, males, and patients who visited in cool seasons suffered heavier burdens. Conclusively, short-term exposure to NO2 was associated with increased outpatient visits for T2DM. Attention should be paid to the impact of NO2 on the burden of T2DM, especially for those vulnerable groups.
•Short-term NO2 exposure was related to increased outpatient T2DM visits.•The association was more obvious in middle-aged adults, males, and cool seasons.•New evidence of positive associations between short-term NO2 and T2DM in China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Single-atom catalysts (SACs), combining the merits of homogeneous and heterogeneous catalysts, have attracted significant interest. Rational design and synthesis of SACs requires a clear ...understanding of the real active sites in different pH solutions. Here, by recognizing the distinct physicochemical properties of H+ and OH− in the oxygen reduction reaction (ORR), we identify two key structures, FeN4 and graphitic-type N-CH (g-type N-CH), to be the catalytic active sites toward the ORR in acidic and alkaline solutions, respectively. This insight is confirmed experimentally by the careful design of a carbon-supported single Fe-atom catalyst (Fe-SAC) containing both of the active sites, which are found to work in synergy. The bi-active site Fe-SAC shows enhanced ORR activity, good long-term stability, and methanol tolerance, as well as the anticipated pH universality. By pinpointing and clarifying the active sites of SACs, this work may inspire chemists to design and synthesize cost-efficient SACs for the ORR.
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Model catalyst exploiting distinct behavior of H+ and OH− in oxygen reduction reactionFeN4 determined to be active oxygen reduction site in acidic solutionGraphitic-type N-CH determined to be active oxygen reduction site in alkaline solutionClarifying active sites in single-atom catalysts may improve future catalyst design
By recognizing the distinct physicochemical effects of H+ and OH− on oxygen reduction, Zhong et al. demonstrate that the structural units of FeN4 and g-type N-CH in their carbon supported single-atom iron catalyst are the main active sites in acidic and alkaline solutions, respectively. This sheds light on the pH dependency of oxygen reduction over cost-efficient single-atom catalysts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background
Increasing nitrogen (N) deposition has altered plant communities globally, however the changes in species abundances with short-term vs. long-term N enrichment remains unclear. ...Stoichiometric homeostasis, quantified by the homoeostatic regulation coefficient (
H
) is a key trait predictive of plant species dominance and species responses to short-term global changes. It is unknown whether
H
changes with N enrichment over time, thereby affecting species responses to long-term N addition.
Methods
Here we investigated three representative plant species how species dominance changed to short-term and long-term N addition with a field N addition experiment (2006–2013) in an Inner Mongolia grassland. Changes in species
H
with long-term N addition were analyzed using a sand culture experiment, and the correlation between species
H
and species abundances were explored to address the above research gaps.
Results
The abundance of
Leymus chinensis
decreased with short-term N addition, and increased with long-term N addition, while
Chenopodium glaucum
exhibited the opposite pattern.
Cleistogenes squarrosa
was only favored by 1-year N addition, and depressed by two or more years of N addition. The
H
values of
L. chinensis
and
C. glaucum
decreased significantly with long-term N addition, but did not change for
C. squarrosa
. The
H
values were significantly related with the abundance both in Control and long-term N addition treatments.
Conclusion
Species abundance had opposite responses to short-term vs. long-term N addition. The decrease of
H
suggested the nutrients use strategy became more progressive, which mediated the responses of species abundances to short- and long-term N addition.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Key message
Thirty significant associations between 22 SNPs and five plant architecture component traits in Chinese upland cotton were identified via GWAS. Four peak SNP loci located on chromosome ...D03 were simultaneously associated with more plant architecture component traits. A candidate gene,
Gh_D03G0922
, might be responsible for plant height in upland cotton.
A compact plant architecture is increasingly required for mechanized harvesting processes in China. Therefore, cotton plant architecture is an important trait, and its components, such as plant height, fruit branch length and fruit branch angle, affect the suitability of a cultivar for mechanized harvesting. To determine the genetic basis of cotton plant architecture, a genome-wide association study (GWAS) was performed using a panel composed of 355 accessions and 93,250 single nucleotide polymorphisms (SNPs) identified using the specific-locus amplified fragment sequencing method. Thirty significant associations between 22 SNPs and five plant architecture component traits were identified via GWAS. Most importantly, four peak SNP loci located on chromosome D03 were simultaneously associated with more plant architecture component traits, and these SNPs were harbored in one linkage disequilibrium block. Furthermore, 21 candidate genes for plant architecture were predicted in a 0.95-Mb region including the four peak SNPs. One of these genes (
Gh_D03G0922
) was near the significant SNP D03_31584163 (8.40 kb), and its
Arabidopsis
homologs contain MADS-box domains that might be involved in plant growth and development. qRT-PCR showed that the expression of
Gh_D03G0922
was upregulated in the apical buds and young leaves of the short and compact cotton varieties, and virus-induced gene silencing (VIGS) proved that the silenced plants exhibited increased PH. These results indicate that
Gh_D03G0922
is likely the candidate gene for PH in cotton. The genetic variations and candidate genes identified in this study lay a foundation for cultivating moderately short and compact varieties in future Chinese cotton-breeding programs.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Three-dimensional (3D) microstructures have various applications in many fields due to their unique physical properties. Manufacturing 3D microstructures with precise micron-scale features is ...difficult. Although the assembly of two-dimensional (2D) structures is a smart way to construct complex 3D microstructures, the way to assemble those 2D structures precisely is still immature. One key issue is that alignment errors often occur during the assembly process, affecting the architecture accuracy of the assembled 3D structures. In this paper, we propose a method to eliminate the alignment error during the self-assembly process only by lateral fluid force. Theoretical analysis has been conducted to demonstrate how alignment errors in the assembly channel are automatically corrected, during which a force perpendicular to the flow direction is generated by the channel’s local spatial asymmetry to automatically correct those alignment errors. Besides, the movement of microstructures in the channel has been numerically simulated, whose results were consistent with the theoretical analysis, and there was indeed a lateral force that causes the self-aligning of the microstructure in the channel. The effect of the microstructure’s dimensions and the channel’s size for self-alignment procedure has also been analyzed. It shows that the self-alignment of the microstructure can complete when the ratio of the diameter of microstructures to the width of the channel is greater than 85%. Besides, experiments of the self-alignment between adjacent layers of microstructures were successful, which show the presented idea using lateral fluid force is a promising way to build 3D structures with less assembly errors.
Boron neutron capture therapy (BNCT) combines neutron irradiation with boron compounds that are selectively uptaken by tumor cells. Boronophenylalanine (BPA) is a boron compound used to treat ...malignant brain tumors. The determination of boron concentration in cells is of great relevance to the field of BNCT. This study was designed to develop a novel method for simultaneously measuring the uptake of BPA by U87 and U251 cells (two brain tumor cell lines) and number of cells using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results revealed a linear correlation between phosphorus intensity and the numbers of U87 and U251 cells, with correlation coefficients (R2) of 0.9995 and 0.9994, respectively. High accuracy and reliability of phosphorus concentration standard curve were also found. Using this new method, we found that BPA had no significant effect on phosphorus concentration in either U87 or U251 cells. However, BPA increased the boron concentration in U87 and U251 cells in a concentration-dependent manner, with the boron concentration in U87 cells being higher than that in U251 cells. In both U87 and U251 cells, boron was mainly distributed in the cytoplasm and nucleus, accounting for 85% and 13% of the total boron uptake by U87 cells and 86% and 11% of the total boron uptake by U251 cells, respectively. In the U87 and U251 cell-derived xenograft (CDX) animal model, tumor exhibited higher boron concentration values than blood, heart, liver, lung, and brain, with a tumor/blood ratio of 2.87 for U87 cells and 3.11 for U251 cells, respectively. These results suggest that the phosphorus concentration in U87 and U251 cells can represent the number of cells and BPA is easily uptaken by tumor cells as well as in tumor tissue.
•Phosphorus can be used for representing cell numbers of U87 and U251.•U87 and U251 cells concentration-dependently uptakes boronophenylalanine.•In U87 and U251 cells, boron was mainly located in cytoplasm and nucleus.•In U87 and U251 CDX model, boron is preferentially distributed in tumor tissue.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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