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•Multiple methods have been introduced for the structure-activity relationship study.•Difference in structure has been firstly used for illustrating the interaction with BSA.•The ...effects of functional group have been discussed thoroughly.•Antioxidant and antibacterial activity of baicalein and wogonin has been compared on structural level.
Flavones (e.g. baicalein and wogonin) extensively used worldwide in food preparation and traditional medicine. In this study, a systematically comparative study of their structure-activity relationships (SAR) on their interaction with BSA, antioxidant activity and antibacterial activity has been carried out by spectrometry, molecular docking and microcalorimetry. Our results show that the skeleton structure of flavones, the number of hydroxyl groups, the type of functional group, conjugated system and the steric hindrance may be responsible for their different biological activity. These findings not only would lay a scientific foundation for discovering and designing flavones-based food and drug, may also help us to understanding the structure-activity relationship between flavones at the molecular level.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Selective separation of acetylene (C2H2) from carbon dioxide (CO2) or ethylene (C2H4) needs specific porous materials whose pores can realize sieving effects while pore surfaces can differentiate ...their recognitions for these molecules of similar molecular sizes and physical properties. We report a microporous material Zn(dps)2(SiF6) (UTSA-300, dps = 4,4′-dipyridylsulfide) with two-dimensional channels of about 3.3 Å, well-matched for the molecular sizes of C2H2. After activation, the network was transformed to its closed-pore phase, UTSA-300a, with dispersed 0D cavities, accompanied by conformation change of the pyridyl ligand and rotation of SiF6 2– pillars. Strong C–H···F and π–π stacking interactions are found in closed-pore UTSA-300a, resulting in shrinkage of the structure. Interestingly, UTSA-300a takes up quite a large amounts of acetylene (76.4 cm3 g–1), while showing complete C2H4 and CO2 exclusion from C2H2 under ambient conditions. Neutron powder diffraction and molecular modeling studies clearly reveal that a C2H2 molecule primarily binds to two hexafluorosilicate F atoms in a head-on orientation, breaking the original intranetwork hydrogen bond and subsequently expanding to open-pore structure. Crystal structures, gas sorption isotherms, molecular modeling, experimental breakthrough experiment, and selectivity calculation comprehensively demonstrated this unique metal–organic framework material for highly selective C2H2/CO2 and C2H2/C2H4 separation.
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IJS, KILJ, NUK, PNG, UL, UM
Polycystic ovarian syndrome (PCOS) is a major severe ovary disorder affecting 5–10% of reproductive women around the world. PCOS can be considered a metabolic disease because it is often accompanied ...by obesity and diabetes. Brown adipose tissue (BAT) contains abundant mitochondria and adipokines and has been proven to be effective for treating various metabolic diseases. Recently, allotransplanted BAT successfully recovered the ovarian function of PCOS rat. However, BAT allotransplantation could not be applied to human PCOS; the most potent BAT is from infants, so voluntary donors are almost inaccessible. We recently reported that single BAT xenotransplantation significantly prolonged the fertility of aging mice and did not cause obvious immunorejection. However, PCOS individuals have distinct physiologies from aging mice; thus, it remains essential to study whether xenotransplanted rat BAT can be used for treating PCOS mice. In this study, rat-to-mouse BAT xenotransplantation, fortunately, did not cause severe rejection reaction, and significantly recovered ovarian functions, indicated by the recovery of fertility, oocyte quality, and the levels of multiple essential genes and kinases. Besides, the blood biochemical index, glucose resistance, and insulin resistance were improved. Moreover, transcriptome analysis showed that the recovered PCOS F0 mother following BAT xenotransplantation could also benefit the F1 generation. Finally, BAT xenotransplantation corrected characteristic gene expression abnormalities found in the ovaries of human PCOS patients. These findings suggest that BAT xenotransplantation could be a novel therapeutic strategy for treating PCOS patients.
In order to take advantage of hybrid materials in their structural diversity and richness of their photoelectric properties, the research in polar materials has been extended to metal‐organic ...compounds in recent years. The main synthesis strategy is to use the molecular dynamics. Here, we describe that the second harmonic generation (SHG) switching effect can be effectively achieved by combination of coordination distortion of metal ions with s2 electrons and molecular dynamics. We synthesized a noncentrosymmetric complex, (1S,4S)‐(+)‐2‐aza‐5‐oxabicyclo2.2.1heptane)2SbCl5, and found that it undergoes an isomorphic phase transition at 382 K. Accompanying the phase transition, the SHG experiences a switching process, and its strength changes from 0.2 times of that of KDP to only noise level. Systematic characterization reveals that the significant change of coordination distortion of the Sb3+ and the change of thermal motion of organic cations lead to the SHG switching effect. This finding shows that the combination of lone pair electron effect of metal ion and molecular dynamics characteristics would be a feasible strategy in development of polar hybrid materials.
A chiral organic‐inorganic hybrid compound (1S, 4S)‐(+)‐2‐Aza‐5‐oxabicyclo2.2.1heptane)2SbCl5 was constructed and found to show SHG switching effect at transition temperature 382 K. The SHG switching effect is due to the coordination distortion caused by the lone pair electron effect. This finding reveals that the lone pair electron effect might be an effective element in the synthesis of polar hybrid materials.
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BFBNIB, FZAB, GIS, IJS, KILJ, OILJ, SBCE, SBMB, UPUK
Highly-efficient oxygen evolution reaction (OER) and reduction of carbon dioxide (CO 2 RR) represent the two biggest scientific challenges in artificial photosynthesis. Many efficient and ...cost-affordable electrocatalysts have been reported in the development of electrochemical OER and CO 2 RR; however, during the electro-derived oxidation or reduction processes, a critical fact that, most catalysts tend to undergo structural reconstruction and/or surface rearrangement, has been widely observed, which greatly subverts the traditional conception of “catalysts”. In this respect, the research trends have gradually transferred from optimizing catalyst materials to elucidating the real active sites of the catalysts as well as understanding the underlying mechanisms behind these complex reactions. Most importantly, the in situ / operando characterization techniques are powerful tools to achieve this goal. Herein, recent advances in the in situ X-ray diffraction and absorption spectroscopy that have provided a unique opportunity to investigate the structural reconstruction and/or surface rearrangement of catalysts under realistic OER and CO 2 RR conditions are thoroughly reviewed. Finally, the challenges of the material design are discussed, and the future perspective for developing next-generation catalysts with imperative requirements of material nature is provided.
The catalytic asymmetric construction of N−N atropisomeric biaryls remains a formidable challenge. Studies of them lag far behind studies of the more classical carbon‐carbon biaryl atropisomers, ...hampering meaningful development. Herein, the first palladium‐catalyzed enantioselective C−H activation of pyrroles for the synthesis of N−N atropisomers is presented. Structurally diverse indole‐pyrrole atropisomers possessing a chiral N−N axis were produced with good yields and high enantioselectivities by alkenylation, alkynylation, allylation, or arylation reactions. Furthermore, the kinetic resolution of trisubstituted N−N heterobiaryls with more sterically demanding substituents was also achieved. Importantly, this versatile C−H functionalization strategy enables iterative functionalization of pyrroles with exquisite selectivity, expediting the formation of valuable, complex, N−N atropisomers.
Enantioselective synthesis of N−N indole‐pyrrole and bisindole atropisomers was achieved by a palladium‐catalyzed TDG‐enabled C−H functionalization. A wide variety of the N−N atropisomers were produced in good yields with excellent enantioselectivities by C−H alkenylation, alkynylation, allylation or arylation reactions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Obesity increases the risk of developing cardiovascular disease and other metabolic diseases. We intended to compare three different anthropometric indicators of obesity, in predicting the incidence ...of cardiovascular events in Chinese type 2 diabetes. Beijing Community Diabetes Study was a prospective multi-center study conducted in Beijing community health centers. Type 2 diabetes patients from fourteen community health centers were enrolled at baseline. The primary endpoint was cardiovascular events. The upper quartile of neck circumference (NC) was set as greater NC. A total of 3299 diabetes patients were enrolled. In which, 941 (28.52%) had cardiovascular disease at baseline. Logistic analysis showed that central obesity (waist circumference (WC) above 90 cm in men and 85 cm in women) and greater NC were all related to baseline cardiovascular disease (adjusted OR = 1.49, and 1.55). After 10-year follow-up, 340 (10.31%) had cardiovascular events. Compared with patients without cardiovascular events, those having cardiovascular events had higher BMI, larger WC and NC. Cox regression analysis showed that greater WC and NC were all associated with the occurrence of cardiovascular events (adjusted HR = 1.41, and 1.38). A higher NC and WC might increase the risk of cardiovascular events by about 40% in type 2 diabetes patients in Beijing communities.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this study, we reported the covalent post-synthetic modification (PSM) of a luminescent complex to achieve aggregation-induced emission (AIE), prepared using the Schiff base reaction of TPE–CHO ...and HLC–NH2, denoted by HLC–NH2–TPE. HLC–NH2 formed a 2D luminescent complex which was constructed using 4,4′-diamino-1,1′-biphenyl-2,2′-dicarboxylic acid and zinc ions via a solvothermal reaction. HLC–NH2–TPE inherited the luminescence properties of HLC–NH2 and exhibited noticeable AIE properties in response to environmental viscosities and temperature changes. Interestingly, HLC–NH2–TPE displayed a time-dependent luminescence conversion phenomenon in a mixed solution of DMF/H 2 O (v : v/1 : 9).
Mosquito-borne flaviviruses infect both mammals and mosquitoes. RNA interference (RNAi) has been demonstrated as an anti-flavivirus mechanism in mosquitoes; however, whether and how flaviviruses ...induce and antagonize RNAi-mediated antiviral immunity in mammals remains unknown. We show that the nonstructural protein NS2A of dengue virus-2 (DENV2) act as a viral suppressor of RNAi (VSR). When NS2A-mediated RNAi suppression was disabled, the resulting mutant DENV2 induced Dicer-dependent production of abundant DENV2-derived siRNAs in differentiated mammalian cells. VSR-disabled DENV2 showed severe replication defects in mosquito and mammalian cells and in mice that were rescued by RNAi deficiency. Moreover, NS2As of multiple flaviviruses act as VSRs in vitro and during viral infection in both organisms. Overall, our findings demonstrate that antiviral RNAi can be induced by flavivirus, while flavivirus uses NS2A as a bona fide VSR to evade RNAi in mammals and mosquitoes, highlighting the importance of RNAi in flaviviral vector-host life cycles.
Despite many decades of study, the kinematics of the broad-line region of 3C 273 are still poorly understood. We report a new, high signal-to-noise, reverberation mapping campaign carried out from ...2008 November to 2018 March that allows the determination of time lags between emission lines and the variable continuum with high precision. The time lag of variations in Hβ relative to those of the 5100 continuum is days in the rest frame, which agrees very well with the Paschen- region measured by the GRAVITY at The Very Large Telescope Interferometer. The time lag of the Hγ emission line is found to be nearly the same as that for Hβ. The lag of the Fe ii emission is days, longer by a factor of ∼2 than that of the Balmer lines. The velocity-resolved lag measurements of the Hβ line show a complex structure that can be possibly explained by a rotation-dominated disk with some inflowing radial velocity in the Hβ-emitting region. Taking the virial factor of fBLR = 1.3, we derive a BH mass of and an accretion rate of from the Hβ line. The decomposition of its Hubble Space Telescope images yields a host stellar mass of , and a ratio of in agreement with the Magorrian relation. In the near future, it is expected to compare the geometrically thick BLR discovered by the GRAVITY in 3C 273 with its spatially resolved torus in order to understand the potential connection between the BLR and the torus.
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