The process of rapid urbanization results in the flow and agglomeration of regional production factors, which leads to the transformation of the urban-rural territorial system and changes the spatial ...patterns of urban and rural areas. On the basis of the dynamic changes about urban and rural construction land, this research focuses on the processes, influencing factors, and driving mechanisms motivating the urban-rural transformation in the Pearl River Delta Region. Vector data of urban construction land use in 1990, 2000, 2005, and 2017, natural elements, socioeconomic data, geostatistical analysis method, and logistic regression model were all utilized to identify the characteristics of the processes and influencing factors. The driving mechanisms of spatial evolution in urban-rural transformation from regional growth, market development, and government controls were also explained according to analytics. The results reveal the following: (1) The spatial agglomeration of urban-rural transformation was highlighted, and a stable “A” regional spatial structure was formed around Guangzhou, Foshan, Zhuhai, Shenzhen, and Dongguan. (2) The urban-rural transformation changed from a high-intensity expansion mode in the core region to a low-intensity expansion mode in the core periphery region. (3) The urban-rural transformation in the east coast of the Pearl River Delta was better than that in the west coast, and the transformation pace of the Pearl River estuary was faster than that of the periphery region. (4) The urban-rural transformation was affected by natural conditions and socioeconomic development, of which traffic location was the most significant factor. (5) The urban-rural spatial variation originated from the combined effects of regional growth forces, market driving forces, and government control forces.
•We show urban-rural transformations of the Pearl River Delta Region from 1990 to 2017.•Quantitative identification and qualitative analysis show spatial transformations.•Transformation was influenced by external development conditions and internal resources.•Urban-rural development transformation changed from rapid to slow growth.•Spatial configuration of transformation was intense in Guangfo and Shenzhen.
Developing novel approaches to reverse the drug resistance of tumor-repopulating cells （TRCs） or stem cell-like cancer cells is an urgent clinical need to improve outcomes of cancer patients. Here we ...show an innovative approach that reverses drug resistance of TRCs using tumor cell-derived microparficles （T-MPs） containing anti-tumor drugs. TRCs, by virtue of being more deformable than differentiated cancer cells, preferentially take up T-MPs that release anti-tumor drugs after entering cells, which in turn lead to death of TRCs. The underlying mechanisms include interfering with drug efflux and promoting nuclear entry of the drugs. Our findings demonstrate the importance of tu- mor cell softness in uptake of T-MPs and effectiveness of a novel approach in reversing drug resistance of TRCs with promising clinical applications.
Lead (Pb) exposure and heart failure risk Chen, Zihan; Huo, Xia; Chen, Guangcan ...
Environmental science and pollution research international,
06/2021, Letnik:
28, Številka:
23
Journal Article
Recenzirano
Lead (Pb) is a heavy metal with widespread industrial use, but it is also a widespread environmental contaminant with serious toxicological consequences to many species. Pb exposure adversely impacts ...the cardiovascular system in humans, leading to cardiac dysfunction, but its effects on heart failure risk remain poorly elucidated. To better understand the pathophysiological effects of Pb, we review potential mechanisms by which Pb exposure leads to cardiac dysfunction. Adverse effects of Pb exposure on cardiac function include heart failure risk, pressure overload, arrhythmia, myocardial ischemia, and cardiotoxicity. The data reviewed clearly establish that Pb exposure can play an important role in the occurrence and development of heart failure. Future epidemiological and mechanistic studies should be developed to better understand the involvement of Pb exposure in heart failure.
In recent years, time-frequency analysis (TFA) methods have received widespread attention and undergone rapid development. However, traditional TFA methods cannot achieve the desired effect when ...dealing with nonstationary signals. Therefore, this study proposes a new TFA method called the local maximum synchrosqueezing scaling-basis chirplet transform (LMSBCT), which is a further improvement of the scaling-basis chirplet transform (SBCT) with energy rearrangement in frequency and can be viewed as a good combination of SBCT and local maximum synchrosqueezing transform. A better concentration in terms of the time-frequency energy and a more accurate instantaneous frequency trajectory can be achieved using LMSBCT. The time-frequency distribution of strong frequency-modulated signals and multicomponent signals can be handled well, even for signals with close signal frequencies and low signal-to-noise ratios. Numerical simulations and real experiments were conducted to prove the superiority of the proposed method over traditional methods.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In recent years, time-frequency analysis (TFA) methods have received widespread attention and undergone rapid development. However, traditional TFA methods cannot achieve the desired effect when ...dealing with nonstationary signals. Therefore, this study proposes a new TFA method called the local maximum synchrosqueezing scaling-basis chirplet transform (LMSBCT), which is a further improvement of the scaling-basis chirplet transform (SBCT) with energy rearrangement in frequency and can be viewed as a good combination of SBCT and local maximum synchrosqueezing transform. A better concentration in terms of the time-frequency energy and a more accurate instantaneous frequency trajectory can be achieved using LMSBCT. The time-frequency distribution of strong frequency-modulated signals and multicomponent signals can be handled well, even for signals with close signal frequencies and low signal-to-noise ratios. Numerical simulations and real experiments were conducted to prove the superiority of the proposed method over traditional methods.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Polycyclic aromatic hydrocarbon (PAH) exposure alters immunological responses. Research concerning PAH exposure on intestinal immunity of children in electronic waste (e-waste) areas is scarce. The ...aim of this study was to evaluate the effects of polycyclic aromatic hydrocarbon (PAH) pollutants on intestinal mucosal immunity of children in e-waste areas. Results showed higher hydroxylated PAH (OH-PAH) concentrations in e-waste-exposed children, accompanied with higher sialyl Lewis A (SLA) level, absolute lymphocyte and monocyte counts, decreased of percentage of CD4
+
T cells, and had a higher risk of diarrhea. OH-PAH concentrations were negative with child growth. 1-OHNap mediated through WBCs, along with 1-OHPyr, was correlated with an increase SLA concentration. 2-OHFlu, 1-OHPhe, 2-OHPhe, 1-OHPyr, and 6-OHChr were positively correlated with secretory immunoglobulin A (sIgA) concentration. Our results indicated that PAH pollutants caused inflammation, affected the intestinal epithelium, and led to transformation of microfold cell (M cell). M cells initiating mucosal immune responses and the subsequent increasing sIgA production might be an adaptive immune respond of children in the e-waste areas. To our knowledge, this is the first study of PAH exposure on children intestinal immunity in e-waste area, showing that PAH exposure plays a negative role in child growth and impairs the intestinal immune function.
Studies have demonstrated that the sounds of animals from many taxa with nonlinear phenomena (NLP)-caused by nonlinear characteristics of vocal organ dynamics that lead to nonlinear vocal ...phenomena-can influence the behavior of receivers. However, the specific functions of different NLP components have received less attention. In most frog species, females produce few or no vocalizations; in contrast, female Odorrana tormota exhibit a diverse range of calls that are rich in NLP components. Previous field playbacks have shown that the female calls can elicit responses from male frogs. Therefore, we conducted a phonotaxis experiment to investigate the differential effects of different NLP calls by female O. tormota on the vocal behavior of male frogs. The results revealed that calls with subharmonics elicited a greater number of short calls and answering calls from male frogs compared to calls with frequency jumps. However, calls with frequency jumps triggered more staccato calls from males than calls with subharmonics. Additionally, during the phonotaxis experiments, we recorded the initial vocalizations of males in response to playbacks of female calls. The majority of males first produced short calls. Under calls with frequency jumps, most of male frogs approaching within 10 cm of the loudspeaker produced staccato calls instead of "meow" calls or short calls. While under calls with subharmonics, most male frogs preferred to produced short calls. Our findings demonstrate that frequency jumps and subharmonic components in the calls of female O. tormota have different effects on male vocal behaviors. The current study lays a foundation for a further understanding of the function of anuran NLP components.
► We investigated the chemical compositions of Cinnamomum jensenianum oil. ► We assessed the effects of oil on mycelial growth, spore germination in Aspergillus flavus. ► We assessed the effects of ...oil on mycelium weight and AFB1 content in A. flavus. ► We observed the effects of oil on the mycelial ultrastructure changes of A. flavus. ► We assessed the effects of oil on ergosterol synthesis.
The essential oil extracted from the bark of Cinnamomum jensenianum Hand.-Mazz was tested for antifungal activity against Aspergillus flavus. Fifty-five components accounting for 96.66% of the total oil composition were identified by GC–MS. The major components were eucalyptol (17.26%) and α-terpineol (12.52%). Mycelial growth and spore germination was inhibited by the oil in a dose-dependent manner. The oil also exhibited a noticeable inhibition on the dry mycelium weight and the synthesis of aflatoxin B1 (AFB1) by A. flavus, completely restraining AFB1 production at 6μl/ml. The possible mode of action of the oil against A. flavus is discussed based on changes in the mycelial ultrastructure. To confirm the target of the oil in the plasma membrane, studies on the inhibition of ergosterol synthesis were performed. Results show that the oil caused a considerable reduction in the ergosterol quantity. Thus, the essential oil from C. jensenianum can be used as a potential source for food preservative.
With the continuous and rapid rise of urbanization in China, land use transition research has been carried out extensively. Multiple cropping is the content of land use recessive morphology research, ...and it is also a common agricultural system in China. Accordingly, further research on multiple cropping index (MCI) can enrich the land use transition research and help to evaluate China’s food security. In order to examine the spatiotemporal changes and factors influencing the MCI of cultivated land in China, we collected MODIS remote sensing image data and land use classification data and conducted a remote sensing inversion on China’s MCI from 2000, 2005, 2010, and 2015. The spatial distributions and evolution processes of the MCI were explored through spatial mapping, statistical analysis, and processing with the Geographic Information System; moreover, the influencing factors of MCI were explored quantitatively with principal component regression. The results were as follows: (1) at the provincial scale, the average MCI across Guangdong, Guangxi, Hainan, Henan, Anhui, and Jiangsu was high; meanwhile, the average MCI across Heilongjiang, Inner Mongolia, Ningxia, and Qinghai was low. Between 2000 and 2015, the number of provinces with low MCI increased gradually, and the average MCI decreased greatly in the southern provinces. (2) At the county scale, the Taihang Mountains, Qinling Mountains, and Hengduan Mountains formed the boundary of China’s single cropping and multiple cropping indices. Dynamic changes in China’s MCI were obvious, and the number of counties with MCI change values lower than 0 increased gradually. Last, (3) natural conditions, nonagricultural process, cultivated land quality, and agricultural intensification demonstrated different degrees of impact on the MCI; in particular, the influence of nonagricultural industries, pesticides, and agricultural plastic film on the MCI proved especially important. Future research should strengthen the existing work on related transformations in farmers’ livelihoods, especially in terms of the return of rural labor force, the body of agricultural production, agricultural ecological issues, and the balance between increased crop production and reduced environmental pollution. In addition, agricultural policy design should pay more attention to cultivated land quality, the farmer who cultivates the land, and the multiple cropping potential of cultivated land.
Objective To promote efficient utilization and sustainable development of territorial space, this study identified changes in territorial space functions considering different population shrinking ...characteristics, aiming to explore territorial space optimization strategies in response to population shrinking challenges. Methods By integrating multi-source data from county units in Sichuan Province from 2010 to 2020, this study measured population shrinking and territorial space function changes, and delineated territorial space zones based on population shrinking characteristics using elasticity coefficient. Results (1) The relationship between population demand and territorial space supply is the main driver of territorial space function formation and development. Population shrinking affects demand, driving changes in agricultural space management, urban space organization, and ecological space management patterns, thereby reshaping the pattern of territorial space functions. (2) Population shrinking in counties of Sichuan Province exhibited significant spatial differences and agglomeration characteristics, with 69.4% of the counties experiencing population shrinkage. This phenomenon was mainly concentrated in peripheral counties outside the central Chengdu area, as well as in most counties in the southern, northeastern, and southwestern parts of Sichuan. The simultaneous change of population quantity and structure, termed “dual shrinking”, was the main type observed. (3) The overall distribution of territorial space functions in counties of Sichuan showed a high in southeast and low in northwest spatial pattern. From 2010 to 2020, 74.9% of the counties experienced an enhancement in territorial space function. (4) Based on population shrinking characteristics, Sichuan’s county territorial space was divided into growth-oriented, extensive, lagging, intensive, declining, and deteriorating types. Territorial space optimization directions were proposed according to the population challenges and territorial space function changes faced by different types of areas. Conclusion Incorporating population aging into the measurement system for population shrinking provides a more comprehensive understanding of regional population shrinking characteristics.Future territorial space optimization at the county level in Sichuan Province should integrate population shrinking characteristics and changes in territorial space functions. This optimization should involve territorial space planning, comprehensive land consolidation, and policy support, optimizing agricultural, urban, and ecological spaces to meet the spatial development needs under varying population shrinking characteristics.
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