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Whether China can avoid falling into the “ageing trap” and find the main causes of the persistent ageing problem are theoretical and practical issues that need to be explored in depth. Based on inter-provincial panel data from 2006–2019, this paper uses stepwise regression to investigate whether economic growth can influence population ageing through housing prices. The study finds that: firstly, economic growth has a positive effect on population ageing. Secondly, economic growth exacerbates population ageing through the mediating effect of housing prices. Thirdly, economic growth causes regional economic disparities, resulting in a higher level of population ageing in economically developed regions than in non-economically developed regions. From the results of the study, it appears that economic growth has resulted in a larger gap between the income of people of the right age and the price of housing, accompanied by a decline in mortality rates and an increase in the burden of old age under higher levels of medical care, a disincentive to have children and an increase in the problem of ageing. It is recommended that the reform of the housing system should be deepened to facilitate the release of fertility intentions and to overcome the “ageing trap”. JEL: F012.4, F015, F036, F016, F037

The gene fatty acid desaturase 2 (FAD2) exists in multiple copies in the Brassica napus genome and encodes an enzyme that catalyzes the conversion of oleic acid to linoleic acid. In the present study, we characterized the regulatory region controlling the expression of an FAD2 gene located on chromosome C5 of Brassica napus and named it BnFAD2-C5. A long intron was found within the 5′-untranslated region (5′-UTR) of the BnFAD2-C5 gene. This intron, compared with an intron-less control, conferred up to a sixfold increase in green fluorescent protein (GFP) expression in transgenic Arabidopsis, thus suggesting that it makes function through intron-mediated enhancement. The sequence containing the promoter and intron was identified to promote high levels of gene expression in genital organs, particularly in seeds, using qRT-PCR and transgenic Arabidopsis. We identified the different promoter regions responsible for the tissue-specific gene expression through a deletion analysis of the BnFAD2-C5 promoter and a β-glucuronidase and GFP reporter system. The results showed that the −1020 to −319 bp region primarily controls BnFAD2-C5 gene expression in the root, whereas the −1020 to −581 bp region controls expression in the stem, the −581 to −319 bp region controls expression in the leaf, and the −1257 to −1020 bp region probably controls expression in the floral parts. The −319 to −1 bp region is also important, conferring high-level transcription in the seeds. The transcription of BnFAD2-C5 could be induced by salicylic acid and jasmonic acid, and the relative response elements were identified in the −1257 to −1020 bp region and −319 to −1 bp region, respectively.

Accumulated evidence suggests that M2-like polarized tumor associated macrophages (TAMs) plays an important role in cancer progression and metastasis, establishing TAMs, especially M2-like TAMs as an appealing target for therapy intervention. Here we found that metformin significantly suppressed IL-13 induced M2-like polarization of macrophages, as illustrated by reduced expression of CD206, down-regulation of M2 marker mRNAs, and inhibition of M2-like macrophages promoted migration of cancer cells and endothelial cells. Metformin triggered AMPKα1 activation in macrophage and silencing of AMPKα1 partially abrogated the inhibitory effect of metformin in IL-13 induced M2-like polarization. Administration of AICAR, another activator of AMPK, also blocked the M2-like polarization of macrophages. Metformin greatly reduced the number of metastases of Lewis lung cancer without affecting tumor growth. In tumor tissues, the percentage of M2-like macrophage was decreased and the area of pericyte-coated vessels was increased. Further, the anti-metastatic effect of metformin was abolished when the animals were treated with macrophages eliminating agent clodronate liposome. These findings suggest that metformin is able to block the M2-like polarization of macrophages partially through AMPKα1, which plays an important role in metformin inhibited metastasis of Lewis lung cancer.

As a durable and renewable fuel, hydrogen has attracted a huge amount of global interest in its production via different routes. Among these methods, the electrocatalytic hydrogen evolution reaction (HER) is one of the most promising ways for low-cost hydrogen production in the future. In this work, a simple redox hydrothermal method has been developed to fabricate a noble-metal-free MoO2/rGO composite for a highly efficient HER. GO nanosheets provide oxygen-containing functional groups for precursor attachment, and restrict growth of MoO2 nanoparticles (NPs) with a small size due to the space confinement effect among GO layers as well. Benefitting from a synergistic effect between metallic MoO2 NPs and graphene, the obtained MoO2/rGO composite exhibits excellent HER activity with a small onset overpotential of 190 mV, a large cathodic current density, and a small Tafel slope of 49 mV per decade, while MoO2 NPs or rGO itself is not a very efficient HER catalyst. Additionally, the MoO2/rGO composite displays good stability after 1000 potential cycles under both acidic and alkaline conditions. Dramatically improved HER activity and excellent stability are attributed to small size, more active sites, high conductivity and a synergistic effect of MoO2 NPs and graphene. The development of the MoO2/rGO composite as an enhanced active HER catalyst broadens the members of Mo-based HER catalysts and provides an insight into the design and synthesis of other noble-metal-free materials for the cost-effective and environmentally friendly catalyst in electrochemical hydrogen production.

Artificial nacre-like graphene oxide paper has sparked great excitement in the scientific community for its unique properties. The preparation of a bioinspired high-strength nanocomposite paper via a simple vacuum-assisted assembly technique from graphene oxide (GO), tannic acid (TA) and Fe3+ ions is reported in this article. The fabricated papers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic mechanical analysis (DMA). We show that Fe3+ ions only induce limited improvement in the mechanical properties of the graphene oxide paper, while the efficient cross-linking of neighboring sheets by Fe3+–TA complex network can significantly improve the fracture strength and Young's modulus of graphene oxide paper by 150% and 521%, respectively, with an optimal content of 5.7 wt% Fe3+. With general surface binding affinity, TA molecules can be adsorbed to GO sheets and provide binding sites for Fe3+. The Fe3+–TA coordinated compound serves as the “mortar” to stick the GO “bricks” together. The mechanical properties of our paper can be simply varied by controlling the cross-linking condition. The obtained nacre-like ultrastrong GO papers could find potential in energy and sustainability applications.

A high oleic acid rapeseed material M15 (derived from Xiangyou 15 variety) has been received more attention for its significant effect for human health. And it has almost the same physiological characteristic with Xiangyou 15 variety. To find out the difference between high oleic acid rapeseed material and Xiangyou 15 seedling, a comparative proteomic approach based on 2-DE and mass spectrometry was adopted. A total of 277 protein spots showed a significant change in intensity by more than 2.0-fold from M15 compared with Xiangyou 15 variety. Among them, 48 spots that changed at least 3.0-fold were excised from gels and successfully identified by MALDI-TOF/TOF MS. The identified proteins involved in metabolism of carbohydrate and energy (75%), stress and defense (8.3%), photosynthesis (6.3%), protein metabolism (2.1%) and other functions (8.3%). Then real-time quantitative PCR (qPCR) analysis was used to verify the expression levels of differentially expressed proteins, but the results did well agree with the proteomic results. In this work, most of the proteins involved in metabolism of carbohydrate and energy have higher expression in M15, which may reveal M15 has higher metabolism ability. These results provided much information to understand the differences between high oleic acid rapeseed material and Xiangyou 15 variety, which will be useful to screen high oleic rapeseed materials in seedling period.

Based on the sequence of a novel expressed sequence tag (EST), the full-length cDNA of 1 017 nucleotides was cloned from Brassica napus cv. Xiangyou 15 through rapid amplification of cDNA ends (RACE). The gene was designated as Bnhol34 (HQ585980), encoding a protein of 338 amino acids. BLAST analysis showed no high degree of sequence identity to any known gene. The calculated molecular weight of the Bnhol34 protein was 36.23 kDa, and the theoretical isoelectric point was 8.74. The Bnhol34 was also cloned from a high oleic acid mutant 854-1 through homologous cloning. There was no difference between the two Bnhol34 genes. Bnhol34 was localized in a tissue-specific manner in B. napus, and its expression level was about eight-fold greater in Xiangyou 15 seeds than in 854-1. The promoter region sequences of Bnhol34 were then isolated from Xiangyou 15 and 854-1, and a 93-bp deletion was found to occur in the Bnhol34 promoter region of 854-1. Three abscisic acid-responsive cis-elements (ABRE) were identified in the promoter region of Xiangyou 15. Real-time PCR analyses revealed that exogenous abscisic acid increased Bnhol34 expression by about four-fold in Xiangyou 15 seeds, yet did not change Bnhol34 expression in 854-1. It appeared that Bnhol34 might be abscisic acid insensitive in 854-1.

To evaluate the anti-tumor effect of the combination of suberoylanilide hydroxamic acid(SAHA) with statins(lovastatin or simvastatin) on non-small cell lung carcinoma(NSCLC) cells.Human NSCLC A549 cells were treated with SAHA in combination of lovastatin or simvastatin. The cell growth was analyzed by SRB method, and the apoptosis of A549 cells was assessed by flow cytometer. The expression of cleaved poly-ADP-ribose polymerase(cleaved-PARP) and p21 protein was analyzed by Western-blotting when A549 cells were challenged with 2.5μmol/L SAHA and 5μmol/L lovastatin.Lovastatin and simvastatin synergized SAHA in the inhibition of A549 cells. SAHA induced apoptosis was also enhanced by lovastatin. Treatment with 2.5μmol/L SAHA significantly up-regulated the expression of p21 protein in 48 h, while the protein expression was reduced in combined treatment with 5μmol/L lovastatin.Statins can synergize the anti-tumor effect of SAHA in human NSCLC cells through a p21-dependent way.

In the present study, we characterized the transcriptional regulatory region (KF038144) controlling the expression of a constitutive FAD2 in Brassica napus . There are multiple FAD2 gene copies in B. napus genome. The FAD2 gene characterized and analyzed in the study is located on chromosome A5 and was designated as BnFAD 2A5-1. BnFAD 2A5-1 harbors an intron (1192 bp) within its 5′-untranslated region (5′-UTR). This intron demonstrated promoter activity. Deletion analysis of the BnFAD 2A5-1 promoter and intron through the β-glucuronidase (GUS) reporter system revealed that the − 220 to − 1 bp is the minimum promoter region, while − 220 to − 110 bp and + 34 to + 285 bp are two important regions conferring high-levels of transcription. BnFAD 2 transcripts were induced by light, low temperature, and abscisic acid (ABA). These observations demonstrated that not only the promoter but also the intron are involved in controlling the expression of the BnFAD 2A5-1 gene. The intron-mediated regulation is an essential aspect of the gene expression regulation.

The asymmetric benzannulation of chiral Fischer car- bene complexes were investigated with a series of complexes bear- ing either chiral alcohols or chiral amines at the heteroatom stabilizing substituent. A set of seven alkenyl complexes and one aryl complex were prepared from five chiral alcohols; (1S,2R,5S)- (+)-menthol, (1R,2S)-(−)-trans-2-phenylcyclohexanol, (±)-trans-2- methylcyclopentanol, (±)-isoborneol, and (−)-8-phenylmenthol. The reaction of all seven of the alkenyl complexes with pent-1-yne and 3,3-dimethylbut-1-yne gave (arene)chromium tricarbonyl com- plexes with very low asymmetric inductions (0−20% de). The phe- nyl carbene complex derived from (+)-menthol gave good asymmetric induction with 3,3-dimethylbut-1-yne as had been pre- viously reported, but the reaction with pent-1-yne gave lower induc- tion and a much lower chemical yield. Alkenyl complexes bearing prolinol derivatives as the heteroatom stabilizing substituent also gave very low induction in reactions with pent-1-yne and this held true for both E- and Z-isomers of these complexes. An alkenyl car- bene complex derived from the C-2 symmetrical amine, 3,5-dime- thylmorpholine, reacted with pent-1-yne to give moderate yields of the (arene)chromium tricarbonyl complex but only in 10% de. High asymmetric inductions were observed for the cyclohexadienone an- nulation of atropisomeric 2-(N-methyl-3-methylindolyl) carbene complexes prepared from the chiral auxiliary, (4R,5S)-5-phenyl-4- methylimidazolidinone. Each atropisomer gives a single and differ- ent diastereomer of the same 4H-carbazol-4-one where it is the chiral axis of each atropisomer that controls the sense of induction and not the chirality of the auxiliary. Thus it is likely that these com- plexes, unlike all of the others examined in this work, react with acetylenes in a process in which the chiral auxiliary is not free to ro- tate about the carbene carbon in any of the reaction intermediates leading to product formation.

The asymmetric benzannulation of chiral Fischer car- bene complexes were investigated with a series of complexes bear- ing either chiral alcohols or chiral amines at the heteroatom stabilizing substituent. A set of seven alkenyl complexes and one aryl complex were prepared from five chiral alcohols; (1S,2R,5S)- (+)-menthol, (1R,2S)-(−)-trans-2-phenylcyclohexanol, (±)-trans-2- methylcyclopentanol, (±)-isoborneol, and (−)-8-phenylmenthol. The reaction of all seven of the alkenyl complexes with pent-1-yne and 3,3-dimethylbut-1-yne gave (arene)chromium tricarbonyl com- plexes with very low asymmetric inductions (0−20% de). The phe- nyl carbene complex derived from (+)-menthol gave good asymmetric induction with 3,3-dimethylbut-1-yne as had been pre- viously reported, but the reaction with pent-1-yne gave lower induc- tion and a much lower chemical yield. Alkenyl complexes bearing prolinol derivatives as the heteroatom stabilizing substituent also gave very low induction in reactions with pent-1-yne and this held true for both E- and Z-isomers of these complexes. An alkenyl car- bene complex derived from the C-2 symmetrical amine, 3,5-dime- thylmorpholine, reacted with pent-1-yne to give moderate yields of the (arene)chromium tricarbonyl complex but only in 10% de. High asymmetric inductions were observed for the cyclohexadienone an- nulation of atropisomeric 2-(N-methyl-3-methylindolyl) carbene complexes prepared from the chiral auxiliary, (4R,5S)-5-phenyl-4- methylimidazolidinone. Each atropisomer gives a single and differ- ent diastereomer of the same 4H-carbazol-4-one where it is the chiral axis of each atropisomer that controls the sense of induction and not the chirality of the auxiliary. Thus it is likely that these com- plexes, unlike all of the others examined in this work, react with acetylenes in a process in which the chiral auxiliary is not free to ro- tate about the carbene carbon in any of the reaction intermediates leading to product formation.