289 research outputs found

    THE MODELS FOR LAND USE DEVELOPMENT WITH THE ACCELERATION OF URBANIZATION IN URBAN CHINA - A CASE STUDY OF PEARL RIVER DELTA METROPOLIS

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    There appears bran-new models of land use development which is not entirely in accord with national policy in China, especially in the rapid urbanization zone. It results from the conflicts between the active two-system of land use policy and the rapid development of society and economy in these areas. Although it disobeys the national law of land use in some aspects, this phenomenon reveals the irrationality on the active land policy, which has to be reformed for the urban sustainability. After summarizing and analysing the typical models of land use development of the rapid urbanization areas in the Pearl-river Delta metropolitans, the paper gives some conclusions and some suggestions for land policy reform in the future

    How does neighborhood walkability affect obesity? The mediating role of commute mode

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    The walkability of a neighborhood is closely related to residents’ travel behavior and daily life and, ultimately, their health and wellbeing. Although existing studies in this area have reached some enlightening conclusions, few of them have considered residents’ travel attitudes and preferences, or the mediating role of commute mode. Do travel attitudes and preferences matter in the relationship between neighborhood walkability and residents being obese? How does commute mode work as a mediator? To answer these questions, based on the 2019 travel survey data in Guangzhou, this paper uses the Multilevel Linear Model (MLM) to examine the association between neighborhood walkability and residents’ body mass index (BMI). Furthermore, the Mediation Model is used to identify the mediating role of commute mode in the relationship between walkability and BMI. The results show that (1) travel attitudes and preferences do affect the individual’s BMI through the mediator of commute mode. (2) After controlling the individual socio-demographics and travel attitudes and preferences, neighborhood walkability has a significant negative effect on BMI. Meanwhile, walkability has a significant positive effect on the use of non-private motorized commute modes. Non-private motorized commute modes have a significant negative effect on BMI. (3) The mediating effect of commute mode in the relationship of neighborhood walkability with the individual’s BMI is significant. The proportion of mediation is 32.90%. Insights into the relationship between neighborhood walkability, commute mode, and individual BMI highlight the importance of walkable neighborhoods that encourage people to use healthy commute modes

    Impacts of altitude on plant green leaf, fresh litter, and soil stoichiometry in subtropical forests

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    BackgroundEcological stoichiometric characteristics of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) serve as crucial indicators of nutrient cycling and limitation in terrestrial ecosystems. However, our current understanding of stoichiometric characteristics in subtropical forests and their response to different climate conditions is still limited.MethodsWe selected six altitudes ranging from 700 m to 1,200 m to simulate different climate conditions of an evergreen broadleaf forest in Wuyi Mountain, Fujian Province, China. We investigated C, N, P, and K stoichiometry and homeostasis in the green leaves, newly senesced leaf litter (fresh litter), and soil of this forest.ResultsLeaf P and K levels showed a decline with increasing altitude. Notably, the stoichiometric ratios in different components exhibited a bimodal distribution along the altitudinal gradient. Additionally, a decline trend of N resorption efficiencies was observed as altitude increased. Moreover, weak homeostasis was observed in P and K in green leaves. These findings highlighted the significant impact of altitude on the stoichiometry in evergreen broadleaf forest. This study also contributed to our understanding of the nutrient cycling mechanism and plant growth strategies of evergreen forests under different climate conditions

    The ultrafine powder of atractylodis macrocephalae rhizoma improves immune function in naturally aging rats by regulating the PI3K/Akt/NF-κB signaling pathway

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    BackgroundThe phenomenon of population aging presents a significant global challenge, with the aging population in China steadily increasing. As individuals progress in age, there is a gradual deterioration of human organs and systems, as well as a decline in the immune system, referred to as immunosenescence. Atractylodis macrocephalae rhizoma (BZ) has been historically used in China for its medicinal properties, including gastrointestinal improvement, immunomodulation, anti-aging, antioxidant effects, and anti-tumor effects. Nevertheless, there remains a gap in understanding the pharmacological and molecular mechanisms underlying its anti-immunosenescence effects.MethodsThis study employed UPLC-ESI-MS and network pharmacology to create a network map of BZ ultrafine powder (BZU) and its aging targets. Enrichment analysis was then used to identify the primary mechanistic pathways underlying BZU’s anti-immunosenescence effects. The primary components of BZU were quantitatively analyzed using high-performance liquid chromatography (HPLC). Naturally aging rats were used to examine the effects of different oral doses (0.25, 0.5, and 1 g/kg) of BZU over 5 weeks on aging performance, peripheral blood immunophenotyping and cell count, and splenic lymphocyte proliferation rate. To validate the findings of network pharmacology, quantitative RT-PCR, Western blotting, and immunofluorescence analyses were conducted.ResultsOur analyses demonstrated that BZU improved various indicators of aging in naturally aging rats, such as increasing the number of voluntary activities, enhance grip strength and fatigue resistance, increasing the microcirculatory blood flow and improving hematological levels. The BZU administration enhanced T and B lymphocyte proliferation and significantly improved the lymphocyte-to-T cell subpopulation ratio. It can elevate serum IL-2 and IL-4 levels while reducing IL-6, IFN-γ and TNF-α levels in naturally aging rats. Finally, it increased CD3 protein expression in the spleen while decreasing protein levels of PI3K, p-AKT, IKKα/β, and NF-κB. It also decreased the mRNA expression of Pik3cg, Akt1, Pdk1 and Nfκb1.ConclusionThese findings suggest that BZU may enhance lymphocyte proliferation by inhibiting the PI3K/Akt/NF-κB signaling pathway, correcting immune cell imbalances, reducing inflammatory responses, and ultimately enhancing immune function and potentially delaying aging

    Association between serum uric acid and colorectal cancer risk in European population: a two-sample Mendelian randomization study

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    ObjectivesThis study aimed to explore the potential causal associations between serum uric acid (SUA) and the risk of colorectal cancer, colon cancer and rectal cancer.MethodsTwenty-six SUA-related single nucleotide polymorphisms which were identified by a large meta-analysis of genome-wide association studies (GWASs) were used as instrumental variables in the two-sample Mendelian randomization (MR) study. Meta-analyses were used to synthesize the results of multiple GWASs which were extracted from the MRC Integrative Epidemiology Unit GWAS database for each type of cancer. The inverse variance weighted (IVW) method was used as the primary MR method to analyze the association between SUA and colorectal cancer risk. Several sensitivity analyses were performed to test the robustness of results.ResultsThe IVW method showed that there were no causal relationships between SUA and the risk of colorectal cancer [odds ratio (OR): 1.0015; 95% confidence interval (CI): 0.9975–1.0056] and colon cancer (OR: 1.0015; 95% CI: 0.9974–1.0055). The SUA levels were negative correlated with rectal cancer risk (OR: 0.9984; 95% CI: 0.9971–0.9998). The similar results were observed in both males (OR: 0.9987; 95% CI: 0.9975–0.9998) and females (OR: 0.9985; 95% CI: 0.9971–0.9999). The sensitivity analyses suggested no evidence of heterogeneity or horizontal pleiotropy. The leave-one-out analyses showed that one SNP (rs1471633) significantly drove the causal effect of SUA on rectal cancer risk. The MR-Egger regression and weighted median both showed that there were no causal relationships between SUA and the risk of colorectal cancer and its subtypes.ConclusionOverall, there was no linear causal association between SUA and the risk of colorectal cancer. However, further research is needed to investigate the role of higher SUA levels such as hyperuricemia or gout in the occurrence of colorectal cancer

    Building a City with Low Noise Pollution: Exploring the Mental Health Effect Thresholds of Spatiotemporal Environmental Noise Exposure and Urban Planning Solution

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    Urban noise pollution and health hazards have become serious social problems and challenges. Noise prevention and control is the most cost-effective health strategy. However, in urban planning and noise control, reliable evidence is still lacking on individual spatiotemporal environmental noise exposure and its mental health effects. This study used real-time noise exposure data and GPS trackers from 142 volunteers aged 18 to 60 years in Guangzhou, and further analyzed the differences in environmental noise exposure and its mental health impact thresholds under individual spatiotemporal behavior. The results showed that the noise exposure of residents under daily activities has obvious differences in time, space and place. Regarding the threshold relationship between noise exposure and mental health, noise exposure at night, work, personal affairs, travel and sleep activities, as well as at home and work had a threshold effect on residents’ mental health. Noise thresholds were 60 dB, 60 dB, and about 34 dB at night, during work or at a workplace, and while sleeping, respectively. The optimal sound environment for personal affairs, traveling, and at home was around 50 dB, 55–70 dB, and 45 dB, respectively. The environmental noise exposure assessment and mental health impact threshold analysis based on the spatial and temporal activities of individuals will provide important reference for government management departments in planning and policy formulation
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