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1.
Orphanet J Rare Dis ; 16(1): 293, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210339

RESUMO

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare, highly heterogeneous genetic disorder involving the impairment of motile cilia. With no single gold standard for PCD diagnosis and complicated multiorgan dysfunction, the diagnosis of PCD can be difficult in clinical settings. Some methods for diagnosis, such as nasal nitric oxide measurement and digital high-speed video microscopy with ciliary beat pattern analysis, can be expensive or unavailable. To confirm PCD diagnosis, we used a strategy combining assessment of typical symptoms with whole-exome sequencing (WES) and/or low-pass whole-genome sequencing (WGS) as an unbiased detection tool to identify known pathogenic mutations, novel variations, and copy number variations. RESULTS: A total of 26 individuals of Chinese origin with a confirmed PCD diagnosis aged 13 to 61 years (median age, 24.5 years) were included. Biallelic pathogenic mutations were identified in 19 of the 26 patients, including 8 recorded HGMD mutations and 24 novel mutations. The detection rate reached 73.1%. DNAH5 was the most frequently mutated gene, and c.8383C > T was the most common mutated variant, but it is relatively rare in PCD patients from other ethnic groups. CONCLUSION: This study demonstrates the practical clinical utility of combining WES and low-pass WGS as a no-bias detecting tool in adult patients with PCD, showing a clinical characteristics and genetic spectrum of Chinese PCD patients.

2.
Dig Dis Sci ; 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34240323

RESUMO

BACKGROUND: The current study set out to elucidate the specific role of microRNA (miR)-206 in cholangiocarcinoma (CCA) cell biological activities by negatively modulating jumonji AT-rich interactive domain 2 (JARID2). METHODS: Firstly, human intrahepatic biliary epithelial cells and CCA cell lines were selected via the analysis of miR-206 and JARID2 expression patterns in CCA by qRT-PCR. Next, the target relation between miR-206 and JARID2 was predicted by Targetscan and validated using dual-luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay. Subsequently, CCK-8 method, colony formation assay, scratch test, Transwell assay, and western blot analysis were performed to evaluate cancer cell development after the overexpression of miR-206 and/or JARID2, with levels of invasion-related proteins assessed. In addition, xenograft transplantation was also employed to confirm the role of miR-206 in vivo. Lastly, Ki-67 expression pattern was also quantified with immunohistochemistry. RESULTS: It was found that miR-206 was poorly expressed and JARID2 was highly expressed in CCA cell lines. Also, miR-206 overexpression brought about a suppressive effect on cancer cell proliferation, migration, and invasion. Furthermore, miR-206 was observed to target JARID2. Meanwhile, JARID2 overexpression promoted cell growth, while simultaneous overexpression of miR-206 and JARID2 impeded malignant cancer progression, indicating that miR-206 overexpression inhibited cell progression via targeting JARID2. Finally, in vivo experimentation illustrated that miR-206 overexpression suppressed tumor growth and weight, and inhibited the expressions of JARID2 N-cadherin, vimentin, and Ki-67. CONCLUSION: Altogether, our findings clarified that miR-206 inhibited CCA malignancy by negatively regulating JARID2.

3.
Surg Radiol Anat ; 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34232369

RESUMO

PURPOSE: Vascularized pedicled bone-grafting from the cuboid to the talus provides low donor site morbidity and satisfactory outcomes in patients with early-stage talar avascular necrosis. We investigated the anatomy of the rotational vascularized pedicled bone graft from the cuboid. METHODS: 15 embalmed cadaver specimens were perfused with red latex via the popliteal artery. The lateral malleolus was dissected. The course of the lateral tarsal artery and the vascular territory in the cuboid supplied by the lateral tarsal artery were observed. Vessel diameters were measured. RESULTS: The course of the lateral tarsal artery to the cuboid was consistent, and a vascularized pedicle of the lateral tarsal artery was present in all specimens. Mean diameter of the lateral tarsal artery was 1.40 ± 0.12 mm (range 1.67-1.25). Mean length of the vascularized pedicle was 67.15 ± 3.18 mm (range 62.43-74.36). The pedicle bone graft was long enough to reach the bony border of both the lateral and medial malleolus. CONCLUSION: A vascularized pedicled cuboid bone graft based on the lateral tarsal artery has clinical utility for early-stage talar avascular necrosis.

4.
J Asian Nat Prod Res ; 23(8): 724-730, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34253100

RESUMO

Three new flavonoid glycosides, embeliaflavosides A-C (1-3), together with eight known flavonoid glycosides (4-11), were isolated from the fruits of Embelia ribes. Their structures were established based on the analyses of spectroscopic data. Compounds 1-11 were evaluated for antioxidant and α-glucosidase inhibitory activities. The results revealed that compounds 1-11 owned significant ABTS radical scavenging activity with IC50 values of 2.52-9.78 µM, and DPPH scavenging activity with IC50 values of 7.56-26.47 µM, respectively. However, α-glucosidase inhibition assay indicated that all the isolates were inactive.[Formula: see text].

5.
Artigo em Inglês | MEDLINE | ID: mdl-34279165

RESUMO

Background: Amyotrophic lateral sclerosis (ALS) has a complex genetic origin, and how immune dysregulation may contribute to ALS etiology remain unclear. Given the roles played by apolipoprotein E (APOE) signaling in neuroinflammation and neurodegeneration, an improved knowledge of the association between APOE genotypes and ALS risk in Chinese population may help to understand the underlying etiology of the disease. Methods: A retrospective case-control study with participants of Chinese ancestry was conducted, with a total of 683 ALS patients and 369 healthy controls analyzed for APOE genotypes using Sanger sequencing. In addition, 282 of these patients were further analyzed for known ALS risk variants and rare deleterious variants related to immune disorders via whole exome sequencing. Results: Among the 683 ALS patients analyzed (346 males, 337 females; mean age at onset [SD]: 51.9 [10.9]), 145 patients (21.1%) carried ε4, the proportion of which was significantly higher than 16.0% in controls (59/369; OR, 1.42; 95%CI, 1.02-1.98; p = 0.02). There is no evidence supporting the association between APOE genotypes and disease phenotypes. We also didn't find any enrichment of currently known ALS risk variants or variants in genes related to immune abnormality in specific APOE genotypes. Conclusion: Our study highlighted the importance of trans-ethnic studies in identifying genetic risk factors, and the relevance of APOE in ALS etiopathogenesis in Chinese population.

6.
Sci Rep ; 11(1): 13814, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34226605

RESUMO

The study aimed to evaluate the prognostic significance of preoperative systemic inflammatory biomarkers including albumin to globulin ratio (AGR), neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), and platelet to lymphocyte ratio (PLR) and establish a nomogram in hepatocellular carcinoma (HCC) patients after microwave ablation (MWA). 192 HCC patients receiving MWA as initial therapy from the first ward of hepatobiliary surgery were classified as training cohort. Whereas, 84 patients from the second of hepatobiliary surgery were classified as validation cohort. Kaplan-Meier (KM) method and univariate analyses showed that AGR, NLR, LMR, and PLR were significantly associated with OS in the training cohort. Multivariate analysis including clinicopathologic features screened out independent predictors including ascites, tumor size, cancer embolus, AGR, and PLR. Based on those variables, a nomogram for predicting OS was established. The C-index was 0.794 in the training cohort and 0.772 in the validation cohort. Calibration plots identified the nomogram performed well with an ideal model. Compared with Barcelona Clinic Liver Cancer (BCLC) staging system and simple tumor size, the nomogram showed better predictive ability. Besides, the nomogram discovered the highest diagnostic accuracy in predicting postoperative clinical outcome than the combination of the present models with tumor size. In conclusion, the constructed nomogram could accurately predict individualized survival probability and might support clinician in individual treatment optimization and clinical decision-making.

7.
Chin Med J (Engl) ; 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267065

RESUMO

BACKGROUND: Psoriatic arthritis (PsA) is an inflammatory arthropathy characterized by psoriasis and bone erosion on radiology. Dickkopf-1 (Dkk-1) is considered to be the main inhibitor of the Wnt signaling pathway and results in reduced osteoblast proliferation. The aim of this study was to investigate the serum level of Dkk-1 and its association with bone erosion in PsA patients. METHODS: Serum Dkk-1 levels were measured by enzyme-linked immunosorbent assay (ELISA) in 69 patients with PsA and 60 controls, including 39 rheumatoid arthritis (RA) patients, and 21 healthy controls (HCs). Rheumatoid factor and anti-cyclic citrullinated peptide levels were also determined by ELISA. The association of Dkk-1 level with clinical and laboratory features of PsA was analyzed. Logistic regression analysis was used to analyze the risk factors for bone erosion in PsA. RESULTS: Dkk-1 was elevated in 68.1% (47/69) of the patients with PsA, 46.2% (18/39) of RA patients, and 9.5% (2/21) of HCs. Serum Dkk-1 concentration was significantly higher in PsA patients compared with that in HCs. The level of serum Dkk-1 was correlated with a swollen joint count, and levels of complement components 3 and 4. Elevated Dkk-1 level (odds ratio = 4.440, 95% confidence interval: 1.246-15.817, P = 0.021) was identified as the risk factor for bone erosion in PsA. CONCLUSIONS: The serum level of Dkk-1 is abnormally elevated in PsA patients. The elevation of Dkk-1 might be involved in the mechanism of bone erosion in patients with PsA.

8.
Korean J Parasitol ; 59(3): 311-317, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34218604

RESUMO

The present study reports a rare case of Taenia saginata infection, which was initially diagnosed as acute cholecystitis in a Tibetan patient at the Qinghai-Tibetan Plateau pastoral area, China. A 45-year-old female was initially diagnosed with acute cholecystitis at a hospital in China. She had a slight fever, weight loss and constipation and complained of pain in the upper abdomen and left back areas. Increase of monocyte, eosinophil and basophil levels were shown. Taenia sp. eggs were detected in a fecal examination. An adult tapeworm approximately 146 cm in length, whitish-yellow color, was collected from the patient after treatment with traditional Chinese medicine. The adult tapeworm had a scolex and proglottids with genital pores. The scolex was rectangular shape with 4 suckers and rostellum without hooklet. The cox1 gene sequence shared 99.5-99.8% homology with that of T. saginata from other regions in China. The patient was diagnosed finally infected with T. saginata by morphological and molecular charateristics.

9.
J Org Chem ; 2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34242504

RESUMO

The Rh(III)-catalyzed migratory insertion of bis(phenylsulfonyl)carbene into aromatic C-H bonds has been developed. A variety of bis(phenylsulfonyl)methyl derivatives were prepared with good yields under mild conditions. The methylated products were readily obtained after reductive desulfonylation. Furthermore, the diverse transformations of bis(phenylsulfonyl)methyl to trideuteriomethyl, aldehyde, and other functional groups were demonstrated.

10.
Adv Clin Chem ; 103: 1-45, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34229848

RESUMO

Lung cancer (LC) accounts for the majority of cancer-related deaths worldwide. Although screening the high-risk population by low-dose CT (LDCT) has reduced mortality, the cost and high false positivity rate has prevented its general diagnostic use. As such, better and more specific minimally invasive biomarkers are needed in general and for early LC detection, specifically. Autoantibodies produced by humoral immune response to tumor-associated antigens (TAA) are emerging as a promising noninvasive biomarker for LC. Given the low sensitivity of any one single autoantibody, a panel approach could provide a more robust and promising strategy to detect early stage LC. In this review, we summarize the background of TAA autoantibodies (TAAb) and the techniques currently used for identifying TAA, as well as recent findings of LC specific antigens and TAAb. This review provides guidance toward the development of accurate and reliable TAAb as immunodiagnostic biomarkers in the early detection of LC.

11.
PLoS Pathog ; 17(7): e1009745, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34252166

RESUMO

Norovirus (NoV) is the major pathogen causing the outbreaks of the viral gastroenteritis across the world. Among the various genotypes of NoV, GII.4 is the most predominant over the past decades. GII.4 NoVs interact with the histo-blood group antigens (HBGAs) to invade the host cell, and it is believed that the receptor HBGAs may play important roles in selecting the predominate variants by the nature during the evolution of GII.4 NoVs. However, the evolution-induced changes in the HBGA-binding affinity for the GII.4 NoV variants and the mechanism behind the evolution of the NoV-HBGA interactions remain elusive. In the present work, the virus-like particles (VLPs) of the representative GII.4 NoV stains epidemic in the past decades were expressed by using the Hansenula polymorpha yeast expression platform constructed by our laboratory, and then the enzyme linked immunosorbent assay (ELISA)-based HBGA-binding assays as well as the molecular dynamics (MD) simulations combined with the molecular mechanics/generalized born surface area (MMGBSA) calculations were performed to investigate the interactions between various GII.4 strains and different types of HBGAs. The HBGA-binding assays show that for all the studied types of HBGAs, the evolution of GII.4 NoVs results in the increased NoV-HBGA binding affinities, where the early epidemic strains have the lower binding activity and the newly epidemic strains exhibit relative stronger binding intensity. Based on the MD simulation and MMGBSA calculation results, a physical mechanism that accounts for the increased HBGA-binding affinity was proposed. The evolution-involved residue mutations cause the conformational rearrangements of loop-2 (residues 390-396), which result in the narrowing of the receptor-binding pocket and thus tighten the binding of the receptor HBGAs. Our experimental and computational studies are helpful for better understanding the mechanism behind the evolution-induced increasing of HBGA-binding affinity, which may provide useful information for the drug and vaccine designs against GII.4 NoVs.

12.
Ultrason Sonochem ; 76: 105662, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34265635

RESUMO

Fe3O4 was obtained by reacting FeCl2 and FeCl3 with polyethylene glycol, and labeled onto a amphiphilic Janus nanosheet. It was confirmed by infrared spectroscopy, SEM, AFM and EDS that the Fe3O4 nanoparticles changed from hydrophilic to amphiphilic. The oxidative desulfurization performance of amphiphilic iron oxide was studied. Results showed that the Janus nanosheets labeled with Fe3O4 could significantly improve the removal rate of thiophene sulfide in simulated oil synergistically with ultrasonic waves, and the desulfurization rate could reach 100%. Further, the effect of ultrasound on the sensing ability of the oil-water interface was studied and the ultrasonic attenuation coefficient was calculated. In addition to the desulfurization mechanism of Fe3O4, it was found that although the ultrasonic attenuation coefficient of the amphiphilic nanosheets was high, the number of hydroxyl radicals determined the desulfurization efficiency. The amphiphilic Fe ions were more favorable for the formation of hydroxyl radicals than the single hydrophilic ones.

13.
Brain Res Bull ; 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34280480

RESUMO

Poststroke cognitive impairment (PSCI) occurs frequently after stroke, but lacks effective treatments. Previous studies have revealed that high-frequency repetitive transcranial magnetic stimulation (rTMS) has a beneficial effect on PSCI and is often used with other cognitive training methods to improve its effect. This study aimed to evaluate the effect of different combinations of rTMS and cognitive training (rTMS-COG) on PSCI and identify the optimal combination protocol. A cerebral infarction rat model was established by transient middle cerebral artery occlusion (tMCAO). The Morris water maze test was conducted to assess the cognitive function of rats. RNA sequencing and bioinformatics analysis were employed to study the underlying mechanisms. rTMS, COG and rTMS-COG all had beneficial effects on PSCI, while cognitive training immediately after rTMS (rTMS-COG0h) achieved a better effect than cognitive training 1 h and 4 h after rTMS, rTMS and COG. We identified 179 differentially expressed genes (DEGs), including 24 upregulated and 155 downregulated genes, between the rTMS-COG0h and rTMS groups. GO analysis revealed that the major categories associated with the DEGs were antigen procession and presentation, regulation of protein phosphorylation and axoneme assembly. KEGG analysis showed that the DEGs were enriched in processes related to phagosome, circadian entrainment, dopaminergic synapse, apelin signaling pathway, long-term depression, neuroactive ligand-receptor interaction, axon guidance and glucagon signaling pathway. PPI analysis identified Calb2, Rsph1, Ccdc114, Acta2, Ttll9, Dnah1, Dlx2, Dlx1, Ccdc40 and Ccdc113 as related genes. These findings prompt exploration of the potential mechanisms and key genes involved in the effect of rTMS-COG0h on PSCI.

14.
Artigo em Inglês | MEDLINE | ID: mdl-34281117

RESUMO

As one of the most important methods for limiting urban sprawl, the accurate delineation of the urban-rural boundary not only promotes the intensive use of urban resources, but also helps to alleviate the urban issues caused by urban sprawl, realizing the intensive and healthy development of urban cities. Previous studies on delineating urban-rural boundaries were only based on the level of urban and rural development reflected by night-time light (NTL) data, ignoring the differences in the spatial development between urban and rural areas; so, the comprehensive consideration of NTL and point of interest (POI) data can help improve the accuracy of urban-rural boundary delineation. In this study, the NTL and POI data were fused using wavelet transform, and then the urban-rural boundary before and after data fusion was delineated by multiresolution segmentation. Finally, the delineation results were verified. The verification result shows that the accuracy of delineating the urban-rural boundary using only NTL data is 84.20%, and the Kappa value is 0.6549; the accuracy using the fusion of NTL and POI data on the basis of wavelet transform is 93.2%, and the Kappa value is 0.8132. Therefore, we concluded that the proposed method of using wavelet transform to fuse NTL and POI data considers the differences between urban and rural development, which significantly improves the accuracy of the delineation of urban-rural boundaries. Accurate delineation of urban-rural boundaries is helpful for optimizing internal spatial structure in both urban and rural areas, alleviating environmental problems resulting from urban development, assisting the formulation of development policies for urban and rural fringes, and promoting the intensive and healthy development of urban areas.

15.
BMC Med ; 19(1): 150, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34281550

RESUMO

BACKGROUND: Environmental factors are associated with human longevity, but their specificity and causality remain mostly unclear. By integrating the innovative "exposome" concept developed in the field of environmental epidemiology, this study aims to determine the components of exposome causally linked to longevity using Mendelian randomization (MR) approach. METHODS: A total of 4587 environmental exposures extracting from 361,194 individuals from the UK biobank, in exogenous and endogenous domains of exposome were assessed. We examined the relationship between each environmental factor and two longevity outcomes (i.e., surviving to the 90th or 99th percentile age) from various cohorts of European ancestry. Significant results after false discovery rates correction underwent validation using an independent exposure dataset. RESULTS: Out of all the environmental exposures, eight age-related diseases and pathological conditions were causally associated with lower odds of longevity, including coronary atherosclerosis (odds ratio = 0.77, 95% confidence interval [0.70, 0.84], P = 4.2 × 10-8), ischemic heart disease (0.66, [0.51, 0.87], P = 0.0029), angina (0.73, [0.65, 0.83], P = 5.4 × 10-7), Alzheimer's disease (0.80, [0.72, 0.89], P = 3.0 × 10-5), hypertension (0.70, [0.64, 0.77], P = 4.5 × 10-14), type 2 diabetes (0.88 [0.80, 0.96], P = 0.004), high cholesterol (0.81, [0.72, 0.91], P = 0.0003), and venous thromboembolism (0.92, [0.87, 0.97], P = 0.0028). After adjusting for genetic correlation between different types of blood lipids, higher levels of low-density lipoprotein cholesterol (0.72 [0.64, 0.80], P = 2.3 × 10-9) was associated with lower odds of longevity, while high-density lipoprotein cholesterol (1.36 [1.13, 1.62], P = 0.001) showed the opposite. Genetically predicted sitting/standing height was unrelated to longevity, while higher comparative height size at 10 was negatively associated with longevity. Greater body fat, especially the trunk fat mass, and never eat sugar or foods/drinks containing sugar were adversely associated with longevity, while education attainment showed the opposite. CONCLUSIONS: The present study supports that some age-related diseases as well as education are causally related to longevity and highlights several new targets for achieving longevity, including management of venous thromboembolism, appropriate intake of sugar, and control of body fat. Our results warrant further studies to elucidate the underlying mechanisms of these reported causal associations.

16.
Plant Dis ; 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282928

RESUMO

Fusarium graminearum is an important fungus causing a variety of maize diseases, including stalk rot, ear rot and sheath rot. However, conidia of F. graminearum are not easily obtained under normal culture conditions, which seriously affects the identification and pathogenicity assessment of the isolates and screening of resistance sources. This study was undertaken to develop and utilize a rapid sporulation technique of F. graminearum using liquid cultivation, which could meet the needs of various tests. The results show that the optimum conditions for sporulation of F. graminearum were as follows: culture medium, 0.154 mol/L saline; temperature, 28-30℃; incubation time, 96 h; initial pH, 9-10; illumination, continuous ultraviolet light; and shaking speed, 150 rpm. Using this culture method, conidial concentration of tested F. graminearum strains can reach more than 1.5×105 conidia/ml. Compared with the existing methods using mung bean (MB) and carboxylmethyl cellulose (CMC) as matrix, saline is relatively low expensive, and the culture process is relatively quick. Overall, this study provided a systematic, rapid, and simple method to obtain a large number of conidia of F. graminearum.

17.
Psychoneuroendocrinology ; 132: 105353, 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34271522

RESUMO

Consolation is a complex empathic behavior that has recently been observed in some socially living rodents. Despite the growing body of literature suggesting that stress affects some simple form of empathy, the relationship between stress and consolation remains largely understudied. Using monogamous mandarin voles, we found that an acute restraint stress exposure significantly reduced consolation-like behaviors and induced anxiety-like behaviors. Along with these behavioral changes, corticotropin-releasing factor (CRF) and CRF receptor 1 (CRFR1) neurons were activated within the anterior cingulate cortex (ACC) and prelimbic cortex (PrL) but not within the infralimbic cortex (IL). Chemogenetic activation of CRF neurons in the ACC and PrL, recaptured acute stress-induced behavioral dysfunctions. We further observed that intracellular PKA and PKC signaling pathways mediate CRF-induced behavioral dysfunctions, but they work in a regional-specific, sex-biased manner. Together, these results suggest that the local CRF-CRFR1 system within the ACC and PrL is involved in the consolation deficits and anxiety induced by acute stress.

18.
Chaos ; 31(5): 051104, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34240935

RESUMO

Identification of multiple influential spreaders on complex networks is of great significance, which can help us speed up information diffusion and prevent disease from spreading to some extent. The traditional top-k strategy to solve an influence maximization problem based on node centrality is unsuitable for selecting several spreaders simultaneously because of influence overlapping. Besides, other heuristic methods have a poor ability to keep the balance between efficiency and computing time. In this paper, an efficient method is proposed to identify the decentralized influential spreaders on networks by edge percolation under the Susceptible-Infected-Recovered (SIR) model. Thanks to the average size of the connected component where one node is located under the edge percolation equivalent to the final spread range of this node under the SIR model approximately, it inspires us to choose suitable spreaders maximize the spread of influence. The experimental results show that our method has high efficiency compared with other benchmark methods on three synthetic networks and six empirical networks, and it also requires less time and cost.

19.
Ying Yong Sheng Tai Xue Bao ; 32(6): 2169-2179, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34212623

RESUMO

Using the four periods of land use data and socio-economic statistics of Lanzhou City in 1995, 2005, 2015 and 2018, we examined the evolution characteristics and driving forces of urban land use in Lanzhou, with expansion intensity index, Logistic regression, and principal component analysis method. Based on the multi-agent model, the expansion of urban land use in Lanzhou under multiple scenarios in 2025 was simulated using Netlogo software. The results showed that the intensity and scale of urban land expansion in Lanzhou City from 1995 to 2018 showed an increasing trend, with a total of 307 km2 of cultivated land and water area. The expansion of urban land in Lanzhou City was significantly related to regional GDP, social fixed asset investment, population density, population, policy, and terrain. The multi-agent model on the Netlogo software could simulate the expansion trend of urban land in Lanzhou, which provided a reliable simulation method for the expansion of valley-type cities. From 2020 to 2025, urban land use under the comprehensive development scenario, natural expansion development scenario, ecological and farmland protection development scenario all showed an increasing trend. The scale of expansion would range between 42.6-134.3 km2. The expansion mode would mainly be infilled expansion. Our results could provide decision support for the land space planning and ecological environment layout optimization for Lanzhou City.


Assuntos
Conservação dos Recursos Naturais , Urbanização , China , Cidades , Simulação por Computador
20.
Artigo em Inglês | MEDLINE | ID: mdl-34227193

RESUMO

Dielectric constant is a crucial physicochemical property of liquids in tuning solute-solvent interactions and solvation microstructures. Herein the dielectric constant variation of liquid electrolytes regarding to temperatures and electrolyte compositions is probed by molecular dynamics simulations. Dielectric constants of solvents reduce as temperatures increase due to accelerated mobility of molecules. For solvent mixtures with different mixing ratios, their dielectric constants either follow a linear superposition rule or satisfy a polynomial function, depending on weak or strong intermolecular interactions. Dielectric constants of electrolytes exhibit a volcano trend with increasing salt concentrations, which can be attributed to dielectric contributions from salts and formation of solvation structures. This work affords an atomic insight into the dielectric constant variation and its chemical origin, which can deepen the fundamental understanding in solution chemistry.

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