Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-36078514

RESUMO

The low-carbon city has become an important global urban development-oriented goal. One important aspect of urban space is low-carbon urban planning, which has a vital role in urban carbon emissions. Which types of urban form and function allocations are conducive to reducing carbon emissions is therefore a key issue. In this study, the Futian and Luohu Districts of Shenzhen, Guangdong Province, China, are taken as an example to investigate this issue. Firstly, a "head/tail" breaks method based on the third fractal theory is adopted to obtain the minimum evaluation parcel of urban space. Then, the Landscape Shape Index (LSI), Fragmentation Index (C), Shannon's Diversity Index (SHDI), and Density of Public Facilities (Den) are used to evaluate the form and function allocation of each parcel. In addition, the CO2 concentration distribution in this study area is acquired from remote sensing satellite data. Finally, the relationships between urban form, function allocation, and CO2 concentration are obtained. The results show that the lower the urban form index or the higher the urban function index, the less the CO2 concentration. To verify this conclusion, three experiments are designed and carried out. In experiment A, the CO2 concentration of the tested area is reduced by 14.31% by decreasing the LSI and C by 6.1% and 9.4%, respectively. In experiment B, the CO2 concentration is reduced by 15.15% by increasing the SHDI and Den by 16.3% and 12.1%, respectively. In experiment C, the CO2 concentration is reduced by 27.72% when the urban form and function are adjusted in the same was as in experiments A and B.


Assuntos
Carbono , Crowdsourcing , Carbono/análise , Dióxido de Carbono/análise , China , Cidades , Planejamento de Cidades
2.
Huan Jing Ke Xue ; 43(8): 4253-4261, 2022 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-35971721

RESUMO

Taraxacum kok-saghyz Rodin (TSK) is an energy plant that can be used as a raw material for natural rubber. The aim of this study was to examine the remediation potential of TSK to lead (Pb)- and cadmium (Cd)-contaminated farmland soil. In this study, a pot experiment was conducted, and the "Soil Environmental Quality and Agricultural Land Soil Pollution Risk Control Standard (GB 15618-2018)" was used as reference. We set up four different concentrations of Pb and Cd pollution treatment to study the characteristics of the accumulation and tolerance of TSK to Pb and Cd. The results showed that as the content of Pb and Cd in the soil increased, the chlorophyll content and biomass of TSK gradually decreased, and the SOD, POD, and CAT enzyme activities gradually increased. The BCF and TF of Cd were between 1.20 and 1.50, indicating that TSK presented some characteristics of a Cd hyperaccumulator. The BCF and TF of Pb were between 0.71 and 1.11. Thus, TSK was a good Pb enrichment plant and possessed the potential to repair soil with ω(Pb) below 400 mg·kg-1. The accumulation of Pb and Cd gradually increased, and the maximum accumulation of Cd and Pb in the shoots was 9.832 µg·plant-1 and 1091.185 µg·plant-1, respectively. However, in lower concentrations of Pb- and Cd-contaminated soil, the removal rate was greater, and the remediation efficiency was better. Overall, using TSK to repair Pb- and Cd-contaminated farmland soil has good application prospects and economic value.


Assuntos
Poluentes do Solo , Taraxacum , Biodegradação Ambiental , Cádmio/análise , Fazendas , Chumbo , Plantas , Solo , Poluentes do Solo/análise
3.
Artigo em Inglês | MEDLINE | ID: mdl-34574756

RESUMO

The precise simulation of urban space evolution and grasping of the leading factors are the most important basis for urban space planning. However, the simulation ability of current models is lacking when it comes to complicated/unpredictable urban space changes, resulting in flawed government decision-making and wasting of urban resources. In this study, a macro-micro joint decision model was proposed to improve the ability of urban space evolution simulation. The simulation objects were unified into production, living and ecological space to realize "multiple planning in one". For validation of the proposed model and method, remote sensing images, geographic information and socio-economic data of Xuzhou, China from 2000 to 2020 were collected and tested. The results showed that the simulation precision of the cellular automata (CA) model was about 87% (Kappa coefficient), which improved to 89% if using a CA and multi-agent system (MAS) joint model. The simulation precision could be better than 92% using the prosed model. The result of factor weight determination indicated that the micro factors affected the evolution of production and living space more than the macro factors, while the macro factors had more influence on the evolution of ecological space than the micro factors. Therefore, active policies should be formulated to strengthen the ideological guidance towards micro individuals (e.g., a resident, farmer, or entrepreneur), and avoid disordered development of living and production space. In addition, ecological space planning should closely link with the local environment and natural conditions, to improve urban ecological carrying capacity and realize urban sustainable development.


Assuntos
Planejamento de Cidades , Conservação dos Recursos Naturais , China , Cidades , Simulação por Computador , Ecossistema , Humanos , Reforma Urbana
4.
J Biomater Sci Polym Ed ; 30(6): 462-485, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30755095

RESUMO

In this study, a solution chitosan fibroin emulsion with added Silver Nanoparticles (AgNPs) was freeze-dried to be the scaffold, and an asymmetric coating was formed on one side. PRP was loaded onto the composite scaffold using a secondary lyophilization technology to prepare the tissue engineering dressings. AgNPs were characterized using a transmission electron microscope. The morphologies of the composite dressing were examined under a scanning electron microscope. The silver content of the dressing was measured by inductively coupled plasma mass spectrometry. The asymmetric wettability of the composite dressing was demonstrated by water contact angle measurement. Relatively high porosity, favourable moisture retention capability and appropriate tensile strength were observed by measuring the physical and mechanical properties. Satisfactory antibacterial properties against various bacteria and microbial isolation performance were observed by the antibacterial effect analysis in vitro. The total protein slow-release property was measured using the BCA assay. Good biocompatibility and lower sensitization were examined both in vitro and in vivo. In addition, the healing effciency of the composite dressing on infected wound were examined in mice infected wound models. Analysis of wound healing rates, bacterial cultures of wound exudate, whole blood cell analysis and histological examination all showed satisfactory results. These results are demonstrated to provide a potential and possible pathway to promote wound tissue repair and regeneration.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Bandagens/microbiologia , Portadores de Fármacos/química , Plasma Rico em Plaquetas/química , Plasma Rico em Plaquetas/metabolismo , Cicatrização/efeitos dos fármacos , Quitosana/química , Fibroínas/química , Fenômenos Mecânicos , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Prata/química , Molhabilidade
5.
Sensors (Basel) ; 18(11)2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30424568

RESUMO

For ultra-rapid orbits provided by the Global Navigation Satellite System (GNSS), the key parameters, accuracy and timeliness, must be taken into consideration in real-time and near real-time applications. However, insufficient observations in later epochs appear to generate low accuracy in observed orbits, for which a correlation between the Dilution of Precision (DOP) of the orbit parameters and their accuracy is found. To correct the observed GNSS ultra-rapid orbit, a correction method based on the DOP values is proposed by building the function models between DOP values and the orbit accuracy. With 10-day orbit determination experiments, the results show that the observed ultra-rapid-orbit errors, generated by insufficient observations, can be corrected by 12⁻22% for the last three hours of the observed orbits. Moreover, considering the timeliness constraints in ultra-rapid-orbit determination, a DOP amplification factor is defined to weight the contribution of each tracking station and optimize the station distribution in the orbit determination procedure. Finally, six schemes are designed to verify the method and strategy in determining the ultra-rapid orbit based on one-month observations. The orbit accuracy is found to decrease by 1.27⁻6.34 cm with increasing amplification factor from 5⁻20%. Thus, the observed ultra-orbit correction method proposed is ideal when considering accuracy and timeliness in ultra-rapid orbit determination.

6.
Sensors (Basel) ; 18(5)2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29724062

RESUMO

Currently, five new-generation BeiDou (BDS-3) experimental satellites are working in orbit and broadcast B1I, B3I, and other new signals. Precise satellite orbit determination of the BDS-3 is essential for the future global services of the BeiDou system. However, BDS-3 experimental satellites are mainly tracked by the international GNSS Monitoring and Assessment Service (iGMAS) network. Under the current constraints of the limited data sources and poor data quality of iGMAS, this study proposes an improved cycle-slip detection and repair algorithm, which is based on a polynomial prediction of ionospheric delays. The improved algorithm takes the correlation of ionospheric delays into consideration to accurately estimate and repair cycle slips in the iGMAS data. Moreover, two methods of BDS-3 experimental satellite orbit determination, namely, normal equation stacking (NES) and step-by-step (SS), are designed to strengthen orbit estimations and to make full use of the BeiDou observations in different tracking networks. In addition, a method to improve computational efficiency based on a matrix eigenvalue decomposition algorithm is derived in the NES. Then, one-year of BDS-3 experimental satellite precise orbit determinations were conducted based on iGMAS and Multi-GNSS Experiment (MGEX) networks. Furthermore, the orbit accuracies were analyzed from the discrepancy of overlapping arcs and satellite laser range (SLR) residuals. The results showed that the average three-dimensional root-mean-square error (3D RMS) of one-day overlapping arcs for BDS-3 experimental satellites (C31, C32, C33, and C34) acquired by NES and SS are 31.0, 36.0, 40.3, and 50.1 cm, and 34.6, 39.4, 43.4, and 55.5 cm, respectively; the RMS of SLR residuals are 55.1, 49.6, 61.5, and 70.9 cm and 60.5, 53.6, 65.8, and 73.9 cm, respectively. Finally, one month of observations were used in four schemes of BDS-3 experimental satellite orbit determination to further investigate the reliability and advantages of the improved methods. It was suggested that the scheme with improved cycle-slip detection and repair algorithm based on NES was optimal, which improved the accuracy of BDS-3 experimental satellite orbits by 34.07%, 41.05%, 72.29%, and 74.33%, respectively, compared with the widely-used strategy. Therefore, improved methods for the BDS-3 experimental satellites proposed in this study are very beneficial for the determination of new-generation BeiDou satellite precise orbits.

7.
J Am Dent Assoc ; 148(10): 743-749.e9, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28712412

RESUMO

BACKGROUND: The relationship between levels of salivary and serum interleukin (IL)-6 and oral lichen planus (OLP) is not understood fully. The authors conducted a systematic review and meta-analysis to compare levels of salivary and serum IL-6 among people with OLP and healthy control participants. METHODS: The authors searched the literature for studies whose investigators had evaluated the relationships between IL-6 and OLP before treatment. The authors used meta-analysis to compare the standardized mean differences (SMD) of the levels of salivary and serum IL-6 between people who had OLP and people who did not have OLP and between patients with erosive OLP and patients with nonerosive OLP. RESULTS: The results of separate meta-analyses, which included 5 studies each, indicated that the levels of salivary and serum IL-6 were significantly higher among patients with OLP than among healthy control participants (SMD, 2.35; 95% confidence interval [CI], 0.50 to 4.19; P = .01; and SMD, 2.03; 95% CI, 0.74 to 3.33; P = .002; respectively). The results of a meta-analysis of 4 studies indicated that the levels of IL-6 were not significantly different between patients with erosive OLP and patients with nonerosive OLP (SMD, 1.37; 95% CI, -0.26 to 3.00; P = .10). There was significant heterogeneity among the studies (P < .00001). CONCLUSIONS: Through the results of this meta-analysis, the authors found significant differences in the levels of IL-6 in saliva and serum between patients with OLP and healthy control participants. The authors found no differences in the levels of serum IL-6 between patients with erosive OLP and patients with nonerosive OLP. These results should be considered with caution because there was a high degree of heterogeneity among studies. PRACTICAL IMPLICATIONS: Levels of IL-6 in saliva and serum may be potential biomarkers for OLP. However, additional research is needed to confirm findings of this meta-analysis.


Assuntos
Interleucina-6/análise , Líquen Plano Bucal/metabolismo , Saliva/química , Humanos , Interleucina-6/sangue , Líquen Plano Bucal/sangue
8.
Recent Pat Food Nutr Agric ; 6(1): 23-6, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25342148

RESUMO

It is known that the Mediterranean diet (MD), which is characterized by high consumption of vegetables, fruits, cereals, beans, nuts, and olive oil, moderate consumption of fish, white meat, eggs, dairy products, and alcohol, and low consumption of red meat, processed meats, and foods rich in sugars or fats, can reduce the risk of cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, and cancers. Previous epidemiologic studies had confirmed the protective role in the incidence and mortality of gastrointestinal cancers. This review discusses MD and gastrointestinal cancers risk through the studies which examined esophageal cancer, gastric cancer, pancreatic cancer, or colorectal cancer. According to recent studies, MD is associated with a significant reduction in the risk of gastrointestinal cancers. But there is a lack of decisive evidence for the association between MD and its adjuvant treatment effect for gastrointestinal cancers. Considering the complexity of tumor etiology, we propose to design more related researches and more comprehensive data, which include diet, exercise and psychological integrated researches to reveal the relationship between MD and cancer.


Assuntos
Neoplasias Colorretais/prevenção & controle , Dieta Mediterrânea , Neoplasias Esofágicas/prevenção & controle , Neoplasias Pancreáticas/prevenção & controle , Neoplasias Gástricas/prevenção & controle , Animais , Comportamento Alimentar , Humanos , Patentes como Assunto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...