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Polymorphic materials are ubiquitous in nature. Their structural features play a critical role in determining the characteristics. The investigation of phase transition mechanisms between different phases of polymorphs is of great significance for designing material structures, tuning phase components and creating novel materials with specific properties. In the current work, the phase transition of titanium dioxide (TiO2) crystals from brookite to columbite was successfully revealed by quantum dynamics simulations. The reconstructive phase transition mechanism of brookite-to-columbite TiO2 was proposed by systematically simulating the XRD spectra of various states, tracking the breakage and formation of Ti-O bonds, counting the connections of the [TiO6] octahedra, and calculating the Lindemann parameter. This work is expected to shed light on the theoretical basis for regulating the crystal phase composition of TiO2 materials and the phase transition mechanisms between polymorphs.
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Global ornamental horticulture is a major pathway for plant invasions, while urban parks are key areas for introducing non-native ornamental plants. To react appropriately to the challenges (e.g., biological invasion issues) and opportunities (e.g., urban ecosystem services) of herbaceous ornamentals in urban parks, we conducted a comprehensive invasive risk assessment in 363 urban parks in Chongqing, a subtropical city in China. The results found more than 1/3 of the 119 non-native species recorded in urban parks had a high invasion risk, and more than five species had potential invasion risk in 96.29% of the study area, indicating herbaceous ornamentals in urban parks are potentially a pool of invasive species that deserves attention. Moreover, humans have chosen herbaceous ornamentals with more aesthetic characteristics in urban parks, where exotic species were more prominent than native species in floral traits, such as more conspicuous flowers and longer flowering periods. The findings can inform urban plant management, provide an integrated approach to assessing herbaceous ornamentals' invasion risk, and offer insights into understanding the filtering effects of human aesthetic preferences.
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Ecosistema , Parques Recreativos , Humanos , Plantas , Especies Introducidas , ReproducciónRESUMEN
Spontaneous urban plants (SUPs) constitute an important component of urban vegetation, but they have received less attention in urban biodiversity and ecological research, especially at the regional scale. We comprehensively reviewed the occurrence records of SUPs in 59 major cities across China's geographical regions. We systematically analyzed floristic composition profiles and diversity patterns of SUPs at the regional scale and explored their influencing factors. The study identified 1211 SUP species through an extensive search of existing field research studies and fieldwork. The species composition pattern of SUPs, displaying a spatial association with climatic zones, was mainly affected by climatic factors and also anthropogenic factors. At different geographic scales, the life-form characteristics revealed some patterns, with more diverse perennials at the regional scale. The abundance of SUPs and the high proportion of native species suggested that limited urban habitats can still contribute to the enrichment and accumulation of urban biodiversity. However, in the context of globalization, continual species exchanges between neighboring regions at different scales may significantly exacerbate urban-biota homogenization. In conclusion, our study provided a regional-scale case of a synoptic SUP profile. The results furnished a scientific basis for understanding the general patterns of SUPs. The findings could inform sustainable solutions for urban ecological planning and management of spontaneous nature in cities.
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Biodiversidad , Plantas , Biota , China , Ciudades , EcosistemaRESUMEN
Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.
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Bosques , Filogenia , Plantas/clasificación , Plantas/genética , Clima Tropical , Biodiversidad , Conservación de los Recursos Naturales , Monitoreo del AmbienteRESUMEN
Background and Aims: Climate change is expected to have major impacts on high alpine and arctic ecosystems in the future, but empirical data on the impact of long-term warming on lichen diversity and richness are sparse. This study report the effects of 18 years of ambient and experimental warming on lichens and vascular plant cover in two alpine plant communities, a dry heath with sparse canopy cover (54 %) and a mesic meadow with a more developed (67 %) canopy cover, in sub-arctic Sweden. Methods: The effects of long-term passive experimental warming using open top chambers (OTCs) on lichens and total vascular plant cover, and the impact of plant cover on lichen community parameters, were analysed. Key Results: Between 1993 and 2013, mean annual temperature increased about 2 °C. Both site and experimental warming had a significant effect on cover, species richness, effective number of species evenness of lichens, and total plant canopy cover. Lichen cover increased in the heath under ambient conditions, and remained more stable under experimental warming. The negative effect on species richness and effective number of species was driven by a decrease in lichens under experimental warming in the meadow. Lichen cover, species richness, effective number of species evenness were negatively correlated with plant canopy cover. There was a significant negative impact on one species and a non-significant tendency of lower abundance of the most common species in response to experimental warming. Conclusions: The results from the long-term warming study imply that arctic and high alpine lichen communities are likely to be negatively affected by climate change and an increase in plant canopy cover. Both biotic and abiotic factors are thus important for future impacts of climate change on lichens.
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Cambio Climático , Ecosistema , Líquenes/fisiología , Regiones Árticas , Plantas , SueciaRESUMEN
Benign prostatic hyperplasia (BPH) occurs when there is an imbalance between the proliferation and death of prostate cells, which is regulated tightly by estrogen signaling. However, the role of G protein-coupled estrogen receptor (GPER) in prostate cell survival remains ambiguous. In this study, we observed that prostates with epithelial hyperplasia showed increased yes-associated protein 1 (YAP) expression and decreased levels of estrogen and GPER. Blocking YAP through genetic or drug interventions led to reduced proliferation and increased apoptosis in the prostate epithelial cells. Interestingly, GPER agonists produced similar effects. GPER activation enhanced the phosphorylation and degradation of YAP, which was crucial for suppressing cell proliferation and survival. The Gαs/cAMP/PKA/LATS pathway, downstream of GPER, transmitted signals that facilitated YAP inhibition. This study investigated the interaction between GPER and YAP in the prostate epithelial cells and its contribution to BPH development. It lays the groundwork for future research on developing BPH treatments.
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Zeolites are a very important family of catalysts. The catalytic activity of zeolites depends on the distribution of acid sites, which has been extensively studied. However, the relationship between the acid site distribution and catalytic efficiency remains unestablished. An onerous computational burden can be imposed when static calculations are applied to analyze the relationship between a catalyst structure and its energy. To resolve this issue, the current work uses neural network (NN) models to evaluate the relationship. By taking the typical HZSM-5 zeolite as an example, we applied the provided atomic coordinates to predict the energy. The network performances of the artificial neural network (ANN) and high-dimensional neural network (HDNN) are compared using the trained results from a dataset containing the identical number of acid sites. Furthermore, the importance of the feature is examined with the aid of a random forest model to identify the pivotal variables influencing the energy. In addition, the HDNN is employed to forecast the energy of an HZSM-5 system with varying numbers of acid sites. This study emphasizes that the energy of zeolites can be rapidly and accurately predicted through the NN, which can assist our understanding of the relationship between the structure and properties, thereby providing more accurate and efficient methods for the application of zeolite materials.
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Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, this study examined impacts of long-term warming on bryophyte communities. Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Species composition changed significantly from original communities in the heath, but remained similar in mesic meadow. Experimental warming increased beta diversity in the heath. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43 % to 11 % in heath and from 68 % to 35 % in meadow (75 % and 48 % decline, respectively, in original cover), while richness declined by 39 % and 26 %, respectively. Importantly, the decline in cover and richness first emerged after 7 years. Warming caused significant increase in litter in both plant communities. Deciduous shrub and litter cover had negative impact on bryophyte cover. We show that bryophyte species do not respond similarly to climate change. Total bryophyte cover declined in both heath and mesic meadow under experimental long-term warming (by 1.5-3 °C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath are more susceptible to warming than in meadow, supporting the suggestion that bryophytes may be less resistant in drier environments than in wetter habitats. Species loss was slower than the decline in bryophyte abundance, and diversity remained similar in both communities. Increased deciduous shrub and litter cover led to decline in bryophyte cover. The non-linear response to warming over time underlines the importance of long-term experiments and monitoring.
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BACKGROUND: Obesity has been widely recognized as a chronic inflammatory condition and associated with elevated inflammatory indicators including C-reactive protein (CRP) and white blood cell count (WBC). Recent studies have shown elevated CRP or WBC is a significant risk factor for cardiac events and stroke but the clinical significance of CRP and WBC has not been clearly studied in morbidly obese patients. This study is aimed at the clinical significance of WBC and CRP in morbidly obese patients and the change after bariatric surgery. METHODS: The study was a prospectively controlled clinical study. From December 1, 2001 to January 31, 2006, of 640 (442 females and 198 males) consecutive morbid obese patients enrolled in a surgically supervised weight loss program with at least 1 year's follow-up were examined. RESULTS: Of the patients, 476 (74.4%) had elevated CRP and 100 (15.6%) had elevated WBC at preoperative study. CRP and WBC were significantly related and both increased with increasing body mass index (BMI). CRP is also increased with increasing waist, glucose level, hemoglobin, albumin, Ca, insulin, C-peptide, and metabolic syndrome while WBC is increased with metabolic syndrome but decreased with increasing age. Multivariate analysis confirmed fasting glucose level and hemoglobin are independent predictors of the elevation of CRP while age is the only independent predictor for elevated WBC. Both WBC and CRP levels decreased rapidly after obesity surgery. These improvements resulted in a 69.8% reduction of CRP and 26.4% reduction of WBC 1 year after surgery. Although individuals who underwent laparoscopic gastric bypass lost significantly more weight (36.8 +/- 11.7 kg vs. 17.3 +/- 10.8 kg; p = 0.000) and achieved a lower BMI (27.8 +/- 4.6 vs. 35.0 +/- 5.5; p = 0.000) than individuals who underwent laparoscopic gastric banding, there was no difference in the resolution of elevated CRP 1 year after surgery (95.9% vs. 84.5%; p = 0.169) and WBC (99.4% vs. 98.3%; p = 0.323). CONCLUSIONS: Both baseline WBC and CRP are elevated in morbid obese patients but CRP has a better clinical significance. Significant weight reduction 1 year after surgery markedly reduced CRP and WBC with a resolution rate of 93.9% and 98.2% separately. Obesity surgery performed by laparoscopic surgery is recommended for obese patients with elevated CRP or WBC.
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Proteína C-Reactiva/análisis , Gastroplastia , Recuento de Leucocitos , Obesidad Mórbida/sangre , Adulto , Factores de Edad , Glucemia/análisis , Índice de Masa Corporal , Femenino , Hemoglobinas/análisis , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Obesidad Mórbida/cirugía , Periodo PosoperatorioRESUMEN
Lower posterior mediastinal tumors are traditionally excised by conventional thoracotomy or thoracoscopic approaches; however, use of the transdiaphragmatic retroperitoneoscopic approach for these tumors has rarely been reported. Herein, we report a case of a left lower posterior mediastinal paravertebral benign schwannoma in an adult male that was successfully treated with transdiaphragmatic retroperitoneoscopic surgery. The patient presented with no symptoms but had noticed a lesion in the left lower posterior mediastinum two months prior. He underwent transdiaphragmatic retroperitoneoscopic surgery with total resection of the mediastinal mass. To the best of our knowledge, this is the most detailed and challenging case of transdiaphragmatic retroperitoneoscopic surgery to treat a schwannoma in the left lower posterior mediastinum reported to date.
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Laparoscopía/métodos , Neoplasias del Mediastino/cirugía , Neurilemoma/cirugía , Anciano , Diafragma/cirugía , Humanos , Masculino , Procedimientos Quirúrgicos Torácicos/métodos , Resultado del TratamientoRESUMEN
Niche-based and neutrality-based theories are two major classes of theories explaining the assembly mechanisms of local communities. Both theories have been frequently used to explain species diversity and composition in local communities but their relative importance remains unclear. Here, we analyzed 57 assemblages of angiosperm trees in 0.1-ha forest plots across China to examine the effects of environmental heterogeneity (relevant to niche-based processes) and spatial contingency (relevant to neutrality-based processes) on phylogenetic structure of angiosperm tree assemblages distributed across a wide range of environment and space. Phylogenetic structure was quantified with six phylogenetic metrics (i.e., phylogenetic diversity, mean pairwise distance, mean nearest taxon distance, and the standardized effect sizes of these three metrics), which emphasize on different depths of evolutionary histories and account for different degrees of species richness effects. Our results showed that the variation in phylogenetic metrics explained independently by environmental variables was on average much greater than that explained independently by spatial structure, and the vast majority of the variation in phylogenetic metrics was explained by spatially structured environmental variables. We conclude that niche-based processes have played a more important role than neutrality-based processes in driving phylogenetic structure of angiosperm tree species in forest communities in China.
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Magnoliopsida/clasificación , Biodiversidad , Evolución Biológica , China , Bosques , Filogenia , Especificidad de la Especie , Clima TropicalRESUMEN
Species assemblage in a local community is determined by the interplay of evolutionary and ecological processes. The Tropical Niche Conservatism hypothesis proposes mechanisms underlying patterns of biodiversity in biological communities along environmental gradients. This hypothesis predicts that, among other things, clades in areas with warm or wet environments are, on average, older than those in areas with cold or dry environments. Focusing on angiosperm trees in forests, this study tested the age-related prediction of the Tropical Niche Conservatism hypothesis. We related the mean family age of angiosperm trees in 57 local forests from across China with 23 current and paleo-environmental variables, which included all major temperature- and precipitation-related variables. Our study shows that the mean family age of angiosperm trees in local forests was positively correlated with temperature and precipitation. This finding is consistent with the age-related prediction of the Tropical Niche Conservatism hypothesis. Approximately 85% of the variance in the mean family age of angiosperm trees was explained by temperature-related variables, and 81% of the variance in the mean family age of angiosperm trees was explained by precipitation-related variables. Climatic conditions at the Last Glacial Maximum did not explain additional variation in mean family age after accounting for current environmental conditions.
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Evolución Biológica , Clima , Bosques , Magnoliopsida/crecimiento & desarrollo , China , Magnoliopsida/clasificaciónRESUMEN
Irrespective of which side is taken in the densification-sprawl debate, insights into the relationship between urban green space coverage and urbanization have been recognized as essential for guiding sustainable urban development. However, knowledge of the relationships between socio-economic variables of urbanization and long-term green space change is still limited. In this paper, using simple regression, hierarchical partitioning and multi-regression, the temporal trend in green space coverage and its relationship with urbanization were investigated using data from 286 cities between 1989 and 2009, covering all provinces in mainland China with the exception of Tibet. We found that: [1] average green space coverage of cities investigated increased steadily from 17.0% in 1989 to 37.3% in 2009; [2] cities with higher recent green space coverage also had relatively higher green space coverage historically; [3] cities in the same region exhibited similar long-term trends in green space coverage; [4] eight of the nine variables characterizing urbanization showed a significant positive linear relationship with green space coverage, with 'per capita GDP' having the highest independent contribution (24.2%); [5] among the climatic and geographic factors investigated, only mean elevation showed a significant effect; and [6] using the seven largest contributing individual factors, a linear model to predict variance in green space coverage was constructed. Here, we demonstrated that green space coverage in built-up areas tended to reflect the effects of urbanization rather than those of climatic or geographic factors. Quantification of the urbanization effects and the characteristics of green space development in China may provide a valuable reference for research into the processes of urban sprawl and its relationship with green space change.
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Planificación de Ciudades , Conservación de los Recursos Naturales , Urbanización/tendencias , China , Conservación de los Recursos Naturales/economía , Conservación de los Recursos Naturales/métodos , Conservación de los Recursos Naturales/tendencias , Factores Socioeconómicos , Factores de TiempoRESUMEN
The diverse natural environment in China causes the spatial heterogeneity of China population distribution. It is essential to understand the interrelations between the population distribution pattern and natural environment to enhance the understanding of the man-land relationship and the realization of the sustainable management for the population, resources, and environment. This paper analyzed the China population distribution by adopting the index of population density (PD) in combining with spatial statistic method and Lorenz curve, and discussed the effects of the natural factors on the population distribution and the interrelations between the population distribution and 16 indices including average annual precipitation (AAP), average annual temperature (AAT), average annual sunshine duration (AASD), precipitation variation (PV), temperature variation (TV), sunshine duration variation (SDV), relative humidity (RH), aridity index (AI), warmth index ( WI), > or = 5 degrees C annual accumulated temperature (AACT), average elevation (AE), relative height difference (RHD), surface roughness (SR), water system density (WSD), net primary productivity (NPP), and shortest distance to seashore (SDTS). There existed an obvious aggregation phenomenon in the population distribution in China. The PD was high in east China, medium in central China, and low in west China, presenting an obvious positive spatial association. The PD was significantly positively correlated with WSD, AAT, AAP, NPP, AACT, PV, RH, and WI, and significantly negatively correlated with RHD, AE, SDV, SR, and SDTS. The climate factors (AAT, WI, PV, and NPP), topography factors (SR and RHD), and water system factor (WSD) together determined the basic pattern of the population distribution in China. It was suggested that the monitoring of the eco-environment in the east China of high population density should be strengthened to avoid the eco-environmental degradation due to the expanding population, and the conservation of the eco-environment in the central and west China with vulnerable eco-environment should also be strengthened to enhance the population carrying ability of these regions and to mitigate the eco-environmental pressure in the east China of high population density.
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Conservación de los Recursos Naturales , Economía , Ambiente , Densidad de Población , Dinámica Poblacional , China , Demografía , HumanosRESUMEN
Socio-economic factors have significant influences on air quality and are commonly used to guide environmental planning and management. Based on data from 85 long-term daily monitoring cities in China, air quality as evaluated by AOFDAQ-A (Annual Occurrence Frequency of Daily Air Quality above Level III), was correlated to socio-economic variable groups of urbanization, pollution and environmental treatment by variation partitioning and hierarchical partitioning methods. We found: (1) the three groups explained 43.5% of the variance in AOFDAQ-A; (2) the contribution of "environmental investment" to AOFDAQ-A shown a time lag effect; (3) "population in mining sector" and "coverage of green space in built-up area" were respectively the most significant negative and positive explanatory socio-economic variables; (4) using eight largest contributing individual factors, a linear model to predict variance in AOFDAQ-A was constructed. Results from our study provide a valuable reference for the management and control of air quality in Chinese cities.
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Contaminantes Atmosféricos/análisis , Contaminación del Aire/estadística & datos numéricos , Exposición a Riesgos Ambientales/estadística & datos numéricos , China , Ciudades , Exposición a Riesgos Ambientales/análisis , Humanos , Factores Socioeconómicos , UrbanizaciónRESUMEN
BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder in modern society and closely associated with obesity. Because OSA increases the likelihood of complications in the perioperative period, preoperative recognition is very important for bariatric patients. Polysomnography (PSG) remains the gold standard for diagnosis, but it is a time-consuming and expensive examination. Our study is aimed at identifying practical clinical predictors of OSA for bariatric patients. METHODS: From April 2006 to December 2007, 101 morbid obese patients [41 men and 60 women, mean age 30.3 +/- 8.5, mean body mass index (BMI) 43.3 +/- 6.9] who underwent PSG before bariatric surgery were retrospectively studied. The severity of OSA was categorized by the apnea-hypopnea index (AHI) as follows: normal, 0 to 4.9; mild, 5 to 14.9; moderate, 15 to 29.9; and severe, >/=30. Chi-squared tests and linear regression models were used to assess associations between clinical parameters and AHI; P < 0.05 was considered statistically significant. RESULTS: The mean Epworth sleepiness scale (ESS) score was 8.2 +/- 4.7, and the mean AHI was 28.9 +/- 33.8 per hour. Of 101 patients, 83 patients had OSA; including severe (32.7%), moderate (17.8%), and mild (31.7%) OSA; 18.5% had no OSA. Patients with severe OSA are significantly male predominant and had higher BMI, systolic blood pressure, hemoglobin, neck and waist circumference, and ESS scores. In linear regression model analysis, the parameters which positively correlated with AHI were body weight, BMI, systolic blood pressure, diastolic blood pressure, hemoglobin, waist and neck circumferences, and the scores of ESS. Multivariate analysis confirmed that BMI, neck circumference, and scores of ESS are independent predictors of the increasing of AHI. CONCLUSIONS: OSA is highly prevalent (82.2%) in Asian bariatric patients. BMI, neck circumference, and scores of ESS are independent predictors of OSA in these patients.
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Obesidad Mórbida/epidemiología , Apnea Obstructiva del Sueño/diagnóstico , Apnea Obstructiva del Sueño/epidemiología , Adulto , Índice de Masa Corporal , Comorbilidad , Femenino , Humanos , Masculino , Análisis Multivariante , Cuello/anatomía & histología , Obesidad Mórbida/cirugía , Polisomnografía , Factores de Riesgo , Taiwán/epidemiología , Adulto JovenRESUMEN
Based on the analysis of characteristics of forest light environmental heterogeneity, this paper reviewed the research advance in the response of forest seedlings to light environmental heterogeneity from the aspects of photosynthesis, thermal dissipation, biomass accumulation and distribution, morphological traits, germination, and population dynamics, and discussed the ecological significance of different responses of seedling regeneration to light environmental heterogeneity in forest biodiversity maintenance, forest succession, and revegetation. Some suggestions for future research in this field were put forward.