Search

Using nationally representative data from China, this paper investigated the impact of internal migration on sexual attitudes and whether this relationship is moderated by Internet use. We provide evidence that internal migration had a significantly positive impact on attitudes toward the acceptance of premarital sex, extramarital sex, and homosexuality. We also found that the positive nexus between internal migration and sexual attitudes was moderated by Internet use. The results further indicated that internal migration influenced sexual attitudes through extrication from traditional gender role values, the deterioration of subjective well-being, and the improvement of economic status.

This paper explored the role of farmland holding in urban settlement intentions of rural-to-urban migrants in China by decomposing the difference in urban settlement intentions between younger and ...

The differentiation of oligodendroglia from oligodendrocyte precursor cells (OPCs) to complex and extensive myelinating oligodendrocytes (OLs) is a multistep process that involves largescale morphological changes with significant strain on the cytoskeleton. While key chromatin and transcriptional regulators of differentiation have been identified, their target genes responsible for the morphological changes occurring during OL myelination are still largely unknown. Here, we show that the regulator of focal adhesion, Tensin3 (Tns3), is a direct target gene of Olig2, Chd7, and Chd8, transcriptional regulators of OL differentiation. Tns3 is transiently upregulated and localized to cell processes of immature OLs, together with integrin-β1, a key mediator of survival at this transient stage. Constitutive Tns3 loss-of-function leads to reduced viability in mouse and humans, with surviving knockout mice still expressing Tns3 in oligodendroglia. Acute deletion of Tns3 in vivo, either in postnatal neural stem cells (NSCs) or in OPCs, leads to a two-fold reduction in OL numbers. We find that the transient upregulation of Tns3 is required to protect differentiating OPCs and immature OLs from cell death by preventing the upregulation of p53, a key regulator of apoptosis. Altogether, our findings reveal a specific time window during which transcriptional upregulation of Tns3 in immature OLs is required for OL differentiation likely by mediating integrin-β1 survival signaling to the actin cytoskeleton as OL undergo the large morphological changes required for their terminal differentiation.

Although reducing poverty has become an important issue for rural development in China, few studies have analyzed the role of mobile Internet use in multidimensional poverty. To fill this gap, this study investigated the impact of mobile Internet use on multidimensional poverty, using data collected from a household survey in rural China. Because households generally decide whether to use mobile Internet by themselves, an endogenous switching regression model was employed to control for potential selection bias. In total, 9.63% of the households were identified as multidimensionally poor and the adjusted multidimensional poverty incidence was 5.47%. The results also showed that mobile Internet use has a significant negative impact on multidimensional poverty. Further, we provide evidence of heterogeneity in the effect of mobile Internet use across regions. These findings highlight the importance of mobile Internet use in multidimensional poverty reduction strategies for rural households.

Electrocatalytic hydrogenation (ECH) enables the sustainable production of chemicals under ambient condition; however, suffers from serious competition with hydrogen (H2) evolution and the use of precious metals as electrocatalysts. Herein, molybdenum disulfide is for the first time developed as an efficient and noble-metal-free catalyst for ECH via in situ intercalation of ammonia or alkyl-amine cations. This interlayer engineering regulates phase transition (2H → 1 T), and effectively ameliorates electronic configurations and surface hydrophobicity to promote the ECH of biomass-derived oxygenates, while prohibiting H2 evolution. The optimal one intercalated by dimethylamine (MoS2-DMA) is capable of hydrogenating furfural (FAL) to furfuryl alcohol with high Faradaic efficiency of 86.3%–73.3% and outstanding selectivity of >95.0% at −0.25 to −0.65 V (vs. RHE), outperforming MoS2 and other conventional metals. Such prominent performance stems from the enhanced chemisorption and surface hydrophobicity. The chemisorption of H intermediate and FAL, synchronously strengthened on the edge-sites of MoS2-DMA, accelerates the surface elementary step following Langmuir-Hinshelwood mechanism. Moreover, the improved hydrophobicity benefits FAL affinity to overcome diffusion limitation. Discovering the effective modulation of MoS2 from a typical H2 evolution electrocatalyst to a promising candidate for ECH, this study broadens the scope to exploit catalysts used for electrochemical synthesis.

Although mobile Internet has become an integral part of people’s daily life in the world today, research on whether and to what extent mobile Internet use (MIU) affects the subjective well-being (SWB) of older adults is scant. This paper focuses on the SWB-MIU gradients among older Chinese adults and contributes to the literature by exploring the relationship between MIU and SWB across the entire distribution of older adults’ SWB. Using nationally representative data from the China Family Panel Studies, we find that MIU has a significant positive impact on the SWB of older adults in China. Employing an instrumental variable quantile regression approach, we provide robust evidence of an asymmetric distributional impact of MIU on SWB among older Chinese adults. In particular, we find that individuals with lower levels of SWB benefit more from the usage of mobile Internet. The results further indicate that MIU can improve the relationship between older adults and their adult children, and is conducive to the maintenance of kin ties, which we interpret as potential mechanisms through which MIU positively affects SWB among older Chinese adults.

Background The lesion of primary gastric non-Hodgkin’s lymphoma (PGL) originates from the submucosa, so conventional gastroscopy has limited diagnostic potential. This study evaluated the diagnosis and follow-up value of endoscopic ultrasonography (EUS) in PGL. Methods Seventy-nine patients diagnosed with PGL either by EUS and biopsy pathology or by postoperative pathology were included in the study. All subjects underwent EUS with deep targeted biopsy and regular follow-up. Results We found sensitivity and specificity of EUS combined with deep targeted biopsy for PGL as 87.3% (69/79) and 80.0% (20/25) respectively, and the diagnostic accuracy as 85.6% (89/104). EUS combined with deep targeted biopsy had significantly greater diagnostic accuracy than gastroscopy [85.6% (89/104) vs. 57.7% (60/104); (P

An efficient electrocatalyst of molybdenum carbide nanodots on carbon nanosheets (nano-MoC/C-Ns) is prepared via a novel interlayer-confined strategy with the aid of MCM-22(P), a kind of multilayered two-dimensional (2D) zeolite precursor. In this strategy, the confined space of the surfactant-swollen MCM-22(P) plays a critical role in creating a unique sandwich-like structure with Mo-based organic–inorganic nanohybrids which further in situ evolve into ultrafine ∼2 nm MoC nanodots on carbon nanosheets in the following carbonization process. After etching the zeolite layers, the nano-MoC/C-Ns is successfully obtained as an efficient noble-metal-free electrocatalyst for hydrogen evolution. The intimate contact between ultrafine MoC nanodots and C nanosheets, as well as their synergetic effects, endows this catalyst with large exposed active sites and accelerated electron transport. The optimal sample achieves excellent hydrogen evolution reaction performance in acidic, neutral and alkaline media with low η10 values of 126, 185 and 92 mV (vs. the values of 28, 36 and 37 mV for a Pt/C reference in acidic, neutral and alkaline media), respectively. This synthetic strategy provides some hints for designing high-performance carbides for energy conversion and storage.

To explore high-performance carbide catalysts for hydrogen evolution reaction (HER), the rational design of hierarchically porous catalyst benefitting active-site exposure and fast mass transport is extremely demanded. Herein, Chinese ink (CI), used for writing and drawing for thousands of years, is adopted to promote the formation of co-assembly of carbon nanoparticles and Mo-based lamellar organic-inorganic hybrids, which, after pyrolysis in Ar atmosphere, is further converted to 3D hierarchically structured and porous MoCx/C nanocomposites (HSP-MoCx/C) for high-efficient HER. Their skeleton structure, porosity, carbon amounts, phase composition and active species dispersity are well modulated by simply tuning the CI dosage in starting mixture, and its mechanism is monitored via a series of physicochemical characterization techniques. The optimal composite exhibits remarkable HER activity with low overpotentials of 112 and 86 mV at current density of 10 mA cm-2, and the small Tafel slopes of 52 and 50 mV dec-1 in 0.5 M H2SO4 and 1 M KOH solution, respectively. Such performance stems from the combined effects of enhanced ion/mass transport, abundant exposed active sites and high conductivity due to the 3D hierarchically skeleton architecture of catalysts. This work paves a new strategy to design hierarchically porous materials for chemical conversion and energy storage.

While there is a large literature on the determinants of generalized trust, few studies have explored the impact of internal migration and attempted to tackle potential endogeneity issues. Using na...

Laser wakefield acceleration (LWFA) using PW-class laser pulses generally requires cm-scale laser–plasma interaction Rayleigh length, which can be realized by focusing such pulses inside a long underdense plasma with a large f-number focusing optic. Here, we present a new PW-based LWFA instrument at the SG-II 5 PW laser facility, which employs f/23 focusing. The setup also adapted an online probing of the plasma density via Nomarski interferometry using a probe laser beam having 30 fs pulse duration. By focusing 1-PW, 30-fs laser pulses down to a focal spot of 230 µm, the peak laser intensity reached a mild-relativistic level of 2.6 × 1018 W/cm2, a level modest for standard LWFA experiments. Despite the large aspect ratio of >25:1 (transverse to longitudinal dimensions) of the laser pulse, electron beams were observed in our experiment only when the laser pulse experienced relativistic self-focusing at high gas-pressure thresholds, corresponding to plasma densities higher than 3 × 1018 cm−3.

Although the strong positive correlation between parental educational expectations (PEE) and child academic achievement is widely documented, little is known about PEE’s effects on child psychological outcomes and the mechanisms through which it may work. Hence, in this paper, using nationally representative data from the 2013–2014 and 2014–2015 waves of the China Education Panel Survey, we investigated PEE’s causal impact on adolescent subjective well-being (SWB) and the moderating role of the academic pressures that these adolescents perceive. While we provided robust evidence for a positive causal relation between PEE and adolescent SWB, we also found that this relationship is negatively moderated by adolescent-perceived academic pressure, indicating that academic pressure is likely to attenuate the beneficial impact of PEE on adolescent SWB. In addition, the facts that the benefits of PEE are greater for female adolescents and those from migrant, one-child, and non-poor families suggested that it may operate on adolescent SWB through increased family resources, improved family relationships, and higher adolescent aspirations linked to higher PEE.

While quarantine has become a widely used control strategy during the outbreak of the 2019 novel coronavirus disease (COVID-19), empirical research on whether and to what extent quarantine and attitudes towards COVID-19 affect mental health is scant. Using a cross-sectional online survey, this paper is the first from the Chinese outbreak to investigate how quarantine experiences and attitudes towards COVID-19 are related to mental health, and how these relationships change across the distribution of mental health scores. Using quantile regression analysis, we found that home self-quarantine is associated with a decrease in depression and an increase in happiness, while community-level quarantine is associated with decreased happiness, especially for those in the lower happiness quantile. We also found that favorable attitudes towards COVID-19 regarding the credibility of real-time updates and confidence in the epidemic control are associated with lower levels of depression and higher levels of happiness. These effects are stronger in the upper quantile of depression and the median quantile of happiness.

Molybdenum carbides (MoxC) are regarded as low-cost non-noble metal electrocatalysts for the hydrogen evolution reaction (HER). However, most reported powdery MoxC materials suffer from several drawbacks of polymer binders (such as Nafion) including partial blocking of active sites and decreased long-term stability. The recently developed binder-free MoxC materials are based on pre-treated commercial current-collecting substrates such as carbon cloth and carbon fibers, which make it basically impossible to design hierarchical porosity and achieve uniform distribution of active sites. Herein, we successfully synthesized self-supporting binder-free Mo2C composited electrocatalytic materials by integrating Mo2C nanoparticles with three-dimensional (3D) hierarchical porous carbon monoliths (PCMs) via a facile impregnation followed by in situ carbonization treatment (denoted as 3D Mo2C/PCM). As a result, Mo2C nanoparticles of ∼5 nm were uniformly distributed on the in situ transformed carbon matrix, and their uniform macropores (∼9 μm) and open ordered mesopores (5.6 nm) guaranteed fast mass transport and full exposure of active sites. The optimal 3D Mo2C/PCM sample displayed overpotentials of 81 and 47 mV at 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH, respectively, and the corresponding Tafel slopes were 63 and 45 mV dec−1. Benefiting from the outstanding mechanical strength and the easy-to-adjust macromorphology, 3D Mo2C/PCM could be directly used as a self-supporting working electrode without adding any binders. The synthesis strategy in this work may be extended to fabricate other bulky self-supporting carbon-based catalysts.

Migration experience is considered to be an important factor affecting mental health. With the increasing number of rural-to-urban migrant workers returning to their hometowns, the impact of migration experience on rural residents is worthy of noting. Using the data from the 2018 China Labor Dynamics Survey, this paper took migration experience as the identification criteria for returning migrant workers and empirically examined the impact of migration experience on rural residents’ mental health. Our results indicated that migration experience had a significant negative impact on the mental health of rural residents. That is, returning migrant workers had a worse mental health status than that of rural residents who never left their hometowns. Mechanism analysis showed that social support and social comparison played an intermediary role in the impact of migration experience on the mental health of rural residents. We also detected considerable heterogeneity in the effects of migration experience: the short-term returning migrant workers and the passive returning migrant workers are more likely to be negatively affected by the migration experience. Our results emphasized the mental health problem faced by returning migrant workers. The policy makers should strengthen psychological education and mental health consultation according to the intergenerational differences and individual characteristics of returning migrant workers.

Although the Internet has had a profound influence on China’s economy and society, the empirical research pertaining to political consequences of the Internet is highly sparse. This paper investigates the potential relationship between Internet use and trust in government of Chinese netizens. We find robust evidence of a significant positive effect of Internet use on trust in government of netizens in China. The beneficial impact of Internet use on trust in government is found to be heterogeneous across genders and age groups. We also find that the source of information plays a role in explaining Chinese netizens’ attitudes towards their governments. In addition, we find that the key mechanisms through which Internet use affects trust in government are the changes in netizens’ appraisal of government performance, deference to government authority and internal efficacy.

Electrically conductive polymer fibers with high woven properties are in demand by broad application fields. The design of these materials for massive production requires high electrical conductivity, efficient fabrication yield, and economic accessibility. Here, we proposed a technique for fabricating continuous polymer fibers coated with 1D materials. By alternately coating conducting carbon black/polyurethane (PU) composites, single-walled carbon nanotubes (SWCNTs), and/or Ag nanowires (AgNWs) on Nylon-6 continuous fiber, lamellar cladding forms a compact conducting shell on the core fiber. The conductive fiber was continuously fabricated using the coaxial micro-painting technique of a 1D material solution. By keeping the size of the droplet constant at the vicinity of the tip of the flexible micro-painter, the Plateau-Rayleigh (P-R) instability of the wetting layer was depressed at fiber velocity far beyond inertial wetting. The fiber with a 2 μm-thick shell exhibits a conductivity of 53 ± 8 Ω/cm at a coating weight ratio of ∼6 wt % silver corresponding to a fiber conductivity of about 1665 S/cm. The much higher strain durability of the fiber coated with SWCNTs and AgNWs' lamellar structure than the fiber coated with only silver nanowires was explained by the local interlayer conducting paths from the AgNW layer to the SWCNT layer. The fiber maintains 90% conductivity after 105 repeated folding or knotting on the monofilament. The conducting yarns were designed and fabricated into electric circuits in textile. As a typical biomedical and flexible electronic application, a low-frequency electrocardiogram (ECG) signal on these circuits was demonstrated.

To improve the surface corrosion resistance of 42CrMo4 high-strength steel used in a marine environment, this article studied the effects of hard turning on the surface integrity and corrosion resistance of 42CrMo4 high-strength steel through the single factor experimental method, namely hard turning, polarization corrosion, electrochemical impedance spectroscopy, potentiodynamic polarization curve, and salt spray tests. The results indicated that the surface integrity was modified by the hard turning, with a surface roughness lower than Ra 0.8 μm, decreased surface microhardness, fine and uniform surface microstructure, and dominant surface residual compressive stress. The hard turning process was feasible to strengthen the surface corrosion resistance of 42CrMo4 high-strength steel. The better corrosion resistance of the surface layer than that of the substrate material can be ascribed to the uniform carbides and compact microstructure. The corrosion resistance varied with cutting speeds as a result of the changed surface microhardness and residual compressive stress, varied with feed rates as a result of the changed surface roughness, and varied with cutting depths as a result of the changed surface residual compressive stress, respectively. The surface integrity with smaller surface roughness and microhardness and bigger surface residual compressive stress was beneficial for corrosion resistance.

Background: While several studies have found that lower levels of social integration may lead to a deterioration in the health status of migrants, previous research on the nexus between social integration and health has generally ignored the potential endogeneity of social integration. This paper examines the heterogeneous impact of social integration on the health of rural-to-urban migrants in China by exploiting plausibly exogenous, long-term, geographic variation in dialectal diversity. Methods: Drawing on nationally representative data from the 2017 China Migrants Dynamic Survey (n = 117,446), we first regressed self-reported health on social integration using ordinary least squares estimation and then used an ordered probit model as a robustness check. Additionally, to rule out the potential endogeneity of social integration, we relied mainly on an instrumental variable approach and used dialectal diversity as a source of exogenous variation for social integration. Results: We found that social integration has a significant positive impact on rural-to-urban migrants’ health. We also detected considerable heterogeneity in the effects of social integration across gender, generation, and wage levels: the health status of women, more recent generation migrants, and migrants with wages in the middle of wage distribution are more likely to be affected by social integration. Conclusions: We confirmed the beneficial impact of social integration on migrants’ health, which has some important policy implications. Successful migration policies should take the fundamental issue of migrants’ social integration into account.

Microbiota-induced tumorigenesis is well established in solid tumors of the gastrointestinal tract but rarely explored in hematologic malignancies. To determine the role of gut microbiota in lymphoma progression, we performed metagenomic sequencing on human primary gastrointestinal B cell lymphomas. We identified a distinct microbiota profile of intestinal lymphoma, with significantly decreased symbiotic microbes, particularly the genus Eubacterium and notably butyrate-producing Eubacterium rectale. Transfer of E. rectale-deficit microbiota of intestinal lymphoma patients to mice caused inflammation and tumor necrosis factor (TNF) production. Conversely, E. rectale treatment reduced TNF levels and the incidence of lymphoma in sensitized Eμ-Myc mice. Moreover, lipopolysaccharide from the resident microbiota of lymphoma patients and mice synergizes with TNF signaling and reinforces the NF-κB pathway via the MyD88-dependent TLR4 signaling, amalgamating in enhanced intestinal B cell survival and proliferation. These findings reveal a mechanism of inflammation-associated lymphomagenesis and a potential clinical rationale for therapeutic targeting of gut microbiota.

The theoretical and technological achievements in the damage mechanism and evaluation model obtained through the national basic research program “Key Fundamental Scientific Problems on Mechanical Equipment Remanufacturing” are reviewed in this work. Large centrifugal compressor impeller blanks were used as the study object. The materials of the blanks were FV520B and KMN. The mechanism and evaluation model of ultra-high cycle fatigue, erosion wear, and corrosion damage were studied via theoretical calculation, finite element simulation, and experimentation. For ultra-high cycle fatigue damage, the characteristics of ultra-high cycle fatigue of the impeller material were clarified, and prediction models of ultra-high cycle fatigue strength were established. A residual life evaluation technique based on the “β-HV-N” (where β was the nonlinear parameter, HV was the Vickers hardness, and N was the fatigue life) double criterion method was proposed. For erosion wear, the flow field of gas-solid two-phase flow inside the impeller was simulated, and the erosion wear law was clarified. Two models for erosion rate and erosion depth calculation were established. For corrosion damage, the electrochemical and stress corrosion behaviors of the impeller material and welded joints in H2S/CO2 environment were investigated. KISCC (critical stress intensity factor) and da/dt (crack growth rate, where a is the total crack length and t is time) varied with H2S concentration and temperature, and their variation laws were revealed. Through this research, the key scientific problems of the damage behavior and mechanism of remanufacturing objects in the multistrength field and cross-scale were solved. The findings provide theoretical and evaluation model support for the analysis and evaluation of large centrifugal compressor impellers before remanufacturing.

Previous studies examining the impact of social trust on happiness often face the difficulties of tackling the problems of potential endogeneity. Using an instrumental variables strategy and a two-stage residual inclusion approach, this paper explores the causal impact of social trust on individual happiness in China. We find robust evidence that a positive, causal relationship between social trust and happiness exist in China. We also find significant heterogeneity in the impact across genders and places of residence. The happiness of males and urban residents is more likely to be affected by social trust, compared to the happiness of female and rural residents, respectively. We further show that the key mechanisms through which social trust affects happiness are changes in self-reported health, social ties, perceived fairness of the society and subjective socioeconomic status.

We report an automated target positioning method with an accuracy of 2 μ m for a compact laser proton accelerator. This method is based on micrometer-scale dots on the images of transparent targets. In order to interpret the variation of these dots quantitatively, we developed a defocusing method making transparent targets visible as phase objects and applied it in target positioning. Automated positioning of transparent targets can be realized by means of minimizing the standard deviations σ of the pixel values of the images. Fast positioning based on the relationship between the radius of spherical aberration ring and defocusing distance is also discussed. Laser proton acceleration experiments have been carried out to demonstrate the performance of this positioning method.

The percent level energy spread and large divergence of laser-plasma beam are the main challenges of realizing compact short-wavelength free-electron lasers based on laser-plasma accelerators. These issues can be solved with proposed transverse gradient undulator method or bunch decompression method along with proper transport design. We present a study of using an expected 500 MeV laser-plasma beam with 0.3 m m ⋅ m r a d normalized emittance and 0.3 m r a d divergence at Peking University to drive compact free-electron laser at 30 nm. We employ the bunch decompression method with a chromatic matching beamline as well as the transverse gradient undulator method with assumed matched beam. Simulation shows that 700 MW power, 9.7 fs pulse duration and 0.85% relative bandwidth FEL output can be obtained using chromatic matched bunch decompression method. FEL with similar performance can be obtained using the transverse gradient undulator scheme.