822 research outputs found

    An Empirical Study on the Evolution of Employment Structure of Transport, Storage and Post Industry of Beijing During Economic Transition in China

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    Employment structure of transport, storage and post industry is in continuous evolution along with the economic transition, and this paper makes an empirical study on it. This paper analyzes the change in employed laborers, employment structure and industry structure in transport, storage and post industry in Beijing, and makes a comparison with the employment proportion in third industry. Based on the above analysis, this paper gives some policy suggestions to both promote the healthy development of transport, storage and post industry in Beijing and further enhance the industry to absorb laborers

    High-speed rail to prosperity? Assessing the role of transportation improvement in the urban economy

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    Investigate the impact of high-speed rail (HSR) on local economy is of great importance and interest to policy makers and scholars. Though there is a big body of literature in this area, the estimates of such impact are inconsistent or even contradictory. The empirical evidence remains problematic for several reasons: endogenous route placement; omitted variable bias; heterogeneity across different regions; various confounding factors. In this paper, we assess this impact by constructing the appropriate counterfactual in the absence of HSR services with similar GDP level and GDP trend before the debut of HSR services. The control group forms a good fit for the treatment group, and the economic performance of the control group was even slightly stronger than that of the treatment group before 2007. Using the DID method, we find the HSR network promoted local GDP by approximately 3.3 percentage points. The introduction of HSR service helped cities attract more industrial enterprises and achieve more industrial output, but its effect on the service sector was not pronounced. Our results are robust to different sample selection procedures, to the dynamic analyses, to different empirical strategies. Our study thus provides new and solid empirical support to the argument that HSR benefits local economic development

    Oriented self-assembly of anisotropic layered double hydroxides (LDHs) with 2D-on-3D hierarchical structure

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    Layered double hydroxides (LDHs) have been the subject of increasing research due to their unique 2D or 3D structures and promising applications. However, achieving precise control over their morphology and architecture has proven to be a significant challenge. In this work, we present an oriented self-assembly strategy for the synthesis of ultrathin 2D-on-3D CoNi-LDHs nanoflowers (NFs) at ambient temperature. Ex situ and in situ characterization techniques were employed to elucidate the formation process of the 2D-on-3D CoNi-LDHs hierarchical structure. The 2D nanosheets are composed of CoNi(OH)2 seeds that undergo rapid nucleation and growth. Under the influence of oriented attachment and Ostwald ripening, the 2D nanosheets continue to crystallize along the axial and radial directions, resulting in the formation of 2D-on-3D CoNi-LDH NFs. This unique 2D-on-3D LDHs structure possesses an ultrathin thickness of approximately 1.5 nm, nanopores with a diameter of approximately 3.8 nm, and a large surface area of approximately 154 m2/g. These properties manifest excellent energy-storage performance in supercapacitors. Our approach provides important insights into the precise synthesis of LDHs with a 2D-on-3D hierarchical structure. The synthesis of LDHs with well-defined structures is a significant challenge in materials science. Our work contributes to the advancement of this field and has the potential to facilitate the development of new, high-performance energy-storage devices.publishedVersio

    Overexpression of long non-coding RNA NORAD promotes invasion and migration in malignant melanoma via regulating the MIR-205-EGLN2 pathway.

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    Growing evidence suggests that long non-coding RNAs NORAD and miR-205 play a significant role in regulating cancer progression and metastasis. In this study, high expression of NORAD was firstly observed in melanoma tissues and human malignant melanoma cell lines, our aim was to study the interaction of them in the process of invasion and migration of malignant melanoma cells. NORAD, miR-205, and EGLN2 mRNA level in MM cells was detected by qRT-PCR. In situ hybridization (ISH) was performed to detect NORAD expression in MM tissues specimens. Effects of NORAD and miR-205 on Prolyl hydroxylase 2 (EGLN2) expression was explored by western blot in MM cells line. Dual-luciferase reporter assay was performed to verify the interaction relationship between NORAD and miR-205, as well as, miR-205 and EGLN2. Transwell assay was conducted to explore the effects of NORAD and miR-205 in vitro. Xenografts in nude mice experiment were used to confirm the role of NORAD and miR-205 in vivo. In vitro, NORAD knockdown significantly inhibited migration and invasion of malignant melanoma cells and elevated the expression of miR-205, there was an interaction between miR-205 and NORAD in the RNA-induced silencing complex. Upregulation of miR-205 induced significant inhibition of migratory and invasive ability compared with the scrambled control. However, downregulating NORAD largely reversed this effect. Furthermore, the regulatory effects of miR-205 on EGLN2 levels and the induction of endoplasmic reticulum stress were reversed by NORAD. In vivo, deletion of miR-205 induced tumor growth in nude mice. NORAD may play critical roles in tumorigenesis and progression of malignant melanoma by regulating of the miR-205-EGLN2 pathway, and may serve as a new therapeutic target

    Specific Targeting MRI of Chitosan Oligosaccharide Modified Fe3O4 Nanoprobe on Macrophage and the Inhibition of Macrophage Foaming Induced by ox-LDL

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    Atherosclerosis (AS) is a primary cause of morbidity and mortality all over the world. Molecular imaging techniques can enable early localization and diagnosis of atherosclerosis plaques. Recent newly developed chitooligosaccharides (CSO) is considered to be capable of target mannose receptors on the surface of macrophages and to inhibit foam cell formation. Here we present a targeting magnetic resonance imaging (MRI) nanoprobe, which was successfully constructed with polyacrylic acid (PAA) modified nanometer iron oxide (Fe3O4) as the core, and coating with CSO molecules, possessing the abilities of targeted MRI and specifically inhibition of the formation of foamy macrophages in the atherosclerotic process. The experimental results showed that the distributions of PAA-Fe3O4 and CSO-PAA-Fe3O4 were uniform and the corresponding sizes were about 5.93 nm and 8.15 nm, respectively. The Fourier transform infrared spectra (FTIR) testified the CSO was coupled with PAA-Fe3O4 successfully. After coupled with CSO, the r1 of PAA-Fe3O4 was increased from 5.317 mM s-1 to 6.147 mM s-1, indicating their potential as MRI contrast agent. Oil Red O staining and total cholesterols (TC) determination showed that CSO-PAA-Fe3O4 could significantly inhibit the foaming process of RAW264.7 cells induced by oxidatively modified low density lipoprotein (ox-LDL). In vitro cellular MRI displayed that, compared with PAA-Fe3O4,CSO-PAA-Fe3O4 could lower the T1 relaxation time of RAW264.7 cells better. In summary, construction of CSO-PAA-Fe3O4 nanoprobe in this study could realize the targeted MRI of macrophages and inhibition of ox-LDL induced macrophage foaming process. This will provide a new avenue in the diagnosis and treatment of AS

    Effective exploitation potential of shale gas from lower cambrian niutitang formation, Northwestern Hunan, China

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    The marine shale in the Lower Cambrian Niutitang Formation is the dominant shale-gas reservoir in northwestern Hunan, which accounts for more than 70% of unconventional energy in Hunan province. Accurately evaluating the shale-gas exploitation potential is a key to determining whether commercial exploitation standards can be met. In the literature, most existing studies have focused on evaluating the shale-gas exploitation potential based on either accumulation conditions or the shale fracability, which will lead to a gap between the real production and proven gas reserves due to the characteristics of the shaleā€™s low permeability and low porosity. Therefore, further studies are needed to evaluate the effective shale-gas exploitation potential. To address this need, the outcrop shale samples in the Niutitang Formation were collected from the target regions, and the geological characteristics, mechanics behavior, and microstructure performance were discussed via both field data and laboratory tests. The results revealed that the shale-gas exploitation potential in the Niutitang Formation was indicated to be comparable to that of five validated shale-gas exploitation regions in the United States. To further illustrate the effective shale-gas exploitation potential, this study suggested using a comprehensive evaluation framework for this purpose, in which both accumulation condition and the shale fracability are simultaneously considered. Therefore, the shale gas reservoir in the Niutitang Formation has highly effective shale-gas exploitation potential by considering both the accumulation conditions and the shale fracability
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