The distribution of undeformed chip thicknesses is the kinematic “copy” of grain space distribution on a workpiece and has an important influence on the grinding results. In this study, a wheel ...topography model is developed that can be integrated with a workpiece model, a kinematic model and a calculation model of undeformed chip thickness of a single grain to obtain the distribution of undeformed chip thicknesses. In order to verify the integrated model, a single-layer brazed diamond grinding wheel is fabricated, and the topography measurements of the grinding wheel are conducted. The measured data are used in the integrated model to perform a simulation; the simulation results are consistent with the test results. At the same time, the model is verified with grains that are uniformly distributed. Then, simulations utilizing the integrated model are used to thoroughly study the grinding process. The distribution of grain protrusion height can be controlled by radial numerical dressings on the grinding wheel. Thus, the role of the distribution of grain protrusion height on the undeformed chip thickness distribution can be quantified by using radial numerical dressings on the grinding wheel. Additionally, the relationship between the average value of the distribution of undeformed chip thicknesses, hmean, and the surface roughness can be determined by simulation. It is shown that the surface roughness can be controlled quantitatively by radial numerical dressings on the wheel.
•A universal model for the undeformed chip thickness distribution is established.•The model for maximum undeformed chip thickness is only a special case of the universal model.•The surface roughness can be quantitative controlled by adjusting the grain protrusion height distribution.
Urban agglomerations are emerging as new regional units for national participation in global competition and the international division of labor. However, they face increasingly severe resource and ...eco-environment pressures during urbanization. The coordination of the relationship between urbanization and the eco-environment has attracted global attention. In this study, we used Coupling Coordination Degree and Vector Autoregression models to examine the dynamic evolution, coupling relationships, coordinated development patterns, and interaction mechanisms between urbanization and the eco-environment. The results indicate that: (1) The level of urbanization in the Chengdu-Chongqing Urban agglomeration was relatively low, and the region showed a good eco-environment background. However, rapid urbanization is gradually straining the carrying capacity of the eco-environment. (2) A close and stable coupling relationship exists between urbanization and the eco-environment, which has reached an advanced coupling stage. The status of coordinated development among cities differs considerably, and multiple stable forms may exist simultaneously. (3) Urbanization has a substantial impact on environmental changes, whereas the restrictive effect of the eco-environment on urbanization development is not particularly notable. (4) Various interactive relationships exist between the urbanization and eco-environment subsystems, including positive promotion and negative constraint effects. The positive promotion effect mainly manifests between the economic, social, and ecological response subsystems, while the negative constraint effect is most evident in the mutual coercion and inhibition between the regional urbanization, economic urbanization, ecological status, and ecological pressure subsystems. These findings have important policy implications for decision makers exploring the path of coordinated and sustainable development in urbanization and the eco-environment in Urban agglomerations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An important adaptation during colonization of land by plants is gravitropic growth of roots, which enabled roots to reach water and nutrients, and firmly anchor plants in the ground. Here we provide ...insights into the evolution of an efficient root gravitropic mechanism in the seed plants. Architectural innovation, with gravity perception constrained in the root tips along with a shootward transport route for the phytohormone auxin, appeared only upon the emergence of seed plants. Interspecies complementation and protein domain swapping revealed functional innovations within the PIN family of auxin transporters leading to the evolution of gravitropism-specific PINs. The unique apical/shootward subcellular localization of PIN proteins is the major evolutionary innovation that connected the anatomically separated sites of gravity perception and growth response via the mobile auxin signal. We conclude that the crucial anatomical and functional components emerged hand-in-hand to facilitate the evolution of fast gravitropic response, which is one of the major adaptations of seed plants to dry land.
The development of urbanization and the protection of the ecological environment are important aspects of sustainable development in urban agglomerations; thus, their coordination and synergy are ...crucial. Scholars in both China and other countries have conducted extensive research on the relationship between urbanization and the ecological environment from the perspective of coordinated development. However, there is a lack of research on the synergistic effects of urbanization and the ecological environment. Taking the Chengdu-Chongqing urban agglomeration as an example, this study uses the Haken model to analyze the synergistic evolution mechanism, development patterns, and future trends of urbanization and the ecological environment. This study draws the following conclusions: (1) while a synergistic development mechanism has been established between urbanization and the ecological environment, the current system is still in a stage of low-level synergy, and the control system's parameter for the direction and path of evolution is urbanization. (2) From 2001 to 2020, the level of synergistic development between urbanization and the ecological environment was relatively low, mainly moving from low-level synergy to medium-low-level synergy to medium-level synergy. (3) There is a significant spatial disparity in the levels of synergistic development, for which the leading region centers on Chengdu and Chongqing in the northwest and southeast, respectively, and the lagging region comprises the eastern part of the urban agglomeration, mainly represented by Dazhou, Kaizhou, and Yunyang. (4) The future trend of synergistic development between urbanization and the ecological environment in the Chengdu-Chongqing urban agglomeration is promising but requires increased infrastructure construction in mountainous urban areas, enhanced cooperation and circulation in transportation, logistics, information and other aspects, and balanced improvements in the level of synergistic development between urbanization and the ecological environment. The study of the synergistic development effect of urbanization and the ecological environment in urban agglomerations is of great significance for reducing the negative impact of urbanization on the ecological environment, increasing the positive interaction between the two, and promoting sustainable development in urban agglomerations.
Long-term exposure to air pollution has been associated with increased lung cancer incidence and mortality. However, the short-term association between air pollution and lung cancer mortality (LCM) ...remains largely unknown.
We collected daily data on particulate matter with diameter <2.5 μm (PM2.5), particulate matter with diameter < 10 μm (PM10), sulfur dioxide (SO2), and ozone (O3), and LCM in three of the biggest cities in China, i.e. Beijing, Chongqing, and Guangzhou, from 2013 to 2015. We first estimated city-specific relationships between air pollutants and LCM using time-series generalized linear models, adjusting for potential confounders. A classification and regression tree (CART) model was used to stratify LCM risk based on combinations of air pollutants and meteorological factors in each city. Then we pooled the city-specific associations using random-effects meta-analysis. Meta regression was used to explore if city-specific characteristics modified the air pollution-LCM association. Finally, we stratified the analyses by season, age, and sex.
Over the entire period, the current-day concentrations of PM2.5 and PM10 in Chongqing and PM2.5, PM10, and SO2 in Guangzhou were positively associated with LCM (Excess risk ranged from 0.72% (95% CI 0.27%–1.17%) to 6.06% (95% CI 0.76%–11.64%) with each 10 μg/m3 increment in different pollutants), but the association between current-day air pollution and LCM in Beijing was not significant (P > 0.05). When considering the environmental and weather factors simultaneously, current-day PM2.5, relative humidity, and PM10 were the most important factors associated with LCM in Beijing, Chongqing, and Guangzhou, respectively. LCM risk related with daily PM2.5, PM10, and SO2 significantly increased with the increasing annual mean temperature and humidity of the city, while LCM risk related with daily O3 significantly increased with the increases of latitude, annual mean O3 concentration, and socioeconomic level. After stratification, the current-day PM2.5, PM10, and O3 during the warm season in Beijing and PM2.5, PM10, and SO2 during the cool season in Chongqing and Guangzhou were positively associated with LCM (Excess risk ranged from 0.93% (95% CI 0.42%–1.45%) to 7.16% (95% CI 0.64%–14.09%) with each 10 μg/m3 increment in different pollutants). Male and the elderly lung cancer patients were more sensitive to the short-term effect of air pollution.
Lung cancer patients should enhance protection measures against air pollution. More attentions should be paid for the high PM2.5, PM10, and O3 during the warm season in Beijing, and high PM2.5, PM10, and SO2 during the cool season in Chongqing and Guangzhou.
•Short-term exposure to air pollution may increase the risk of lung cancer mortality.•The short-term associations between air pollutants and lung cancer mortality varied by city and season.•Daily air pollutants and weather factors had synergistic effects on daily lung cancer mortality.•Male and elder lung cancer patients were more susceptible to air pollution.
Background C3 glomerulonephritis (GN) is a proliferative GN resulting from glomerular deposition of complement factors due to dysregulation of the alternative pathway of complement. Dysregulation of ...the alternative pathway of complement may occur as a result of mutations or functional inhibition of complement-regulating proteins. Functional inhibition of the complement-regulating proteins may result from a monoclonal gammopathy. Study Design Case series. Setting & Participants 32 Mayo Clinic patients with C3 GN, 10 (31%) of whom had evidence of a monoclonal immunoglobulin in serum. Outcomes Clinical features, hematologic and bone marrow biopsy findings, kidney biopsy findings, kidney measures, complement pathway abnormalities, treatment, and follow-up of patients with C3 GN that was associated with a monoclonal gammopathy. Results Mean age of patients with C3 GN associated with monoclonal gammopathy was 54.5 years. Bone marrow biopsy done in 9 patients revealed monoclonal gammopathy of undetermined significance in 5 patients, small lymphocytic lymphoma/chronic lymphocytic leukemia in one patient, and no abnormal clones in the other 3 patients. Kidney biopsy showed membranoproliferative GN with bright capillary wall C3 staining in all 10 patients. Evaluation of the alternative pathway of complement showed abnormalities in 7 of 9 patients tested. No mutation in complement-regulating proteins was detected in any patient. As an index case, one patient with C3 GN and chronic lymphocytic leukemia was treated with rituximab, cyclophosphamide, vincristine, and prednisone, and one patient with C3 GN and monoclonal gammopathy of undetermined significance was treated with dexamethasone and bortezomib. Both patients showed significant decreases in hematuria and proteinuria and stabilization of kidney function. Limitations Studies to show evidence of direct activation of the alternative pathway by monoclonal immunoglobulin were not done. Conclusions The study highlights the association of C3 GN and monoclonal gammopathy, in particular in the older population, and the importance of targeting the underlying hematologic malignancy as an approach to treating C3 GN.
IMPORTANCE: Early onset of myopia is associated with high myopia later in life, and myopia is irreversible once developed. OBJECTIVE: To evaluate the efficacy of low-concentration atropine eyedrops ...at 0.05% and 0.01% concentration for delaying the onset of myopia. DESIGN, SETTING, AND PARTICIPANTS: This randomized, placebo-controlled, double-masked trial conducted at the Chinese University of Hong Kong Eye Centre enrolled 474 nonmyopic children aged 4 through 9 years with cycloplegic spherical equivalent between +1.00 D to 0.00 D and astigmatism less than −1.00 D. The first recruited participant started treatment on July 11, 2017, and the last participant was enrolled on June 4, 2020; the date of the final follow-up session was June 4, 2022. INTERVENTIONS: Participants were assigned at random to the 0.05% atropine (n = 160), 0.01% atropine (n = 159), and placebo (n = 155) groups and had eyedrops applied once nightly in both eyes over 2 years. MAIN OUTCOMES AND MEASURES: The primary outcomes were the 2-year cumulative incidence rate of myopia (cycloplegic spherical equivalent of at least −0.50 D in either eye) and the percentage of participants with fast myopic shift (spherical equivalent myopic shift of at least 1.00 D). RESULTS: Of the 474 randomized patients (mean age, 6.8 years; 50% female), 353 (74.5%) completed the trial. The 2-year cumulative incidence of myopia in the 0.05% atropine, 0.01% atropine, and placebo groups were 28.4% (33/116), 45.9% (56/122), and 53.0% (61/115), respectively, and the percentages of participants with fast myopic shift at 2 years were 25.0%, 45.1%, and 53.9%. Compared with the placebo group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 24.6% 95% CI, 12.0%-36.4%) and percentage of patients with fast myopic shift (difference, 28.9% 95% CI, 16.5%-40.5%). Compared with the 0.01% atropine group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 17.5% 95% CI, 5.2%-29.2%) and percentage of patients with fast myopic shift (difference, 20.1% 95% CI, 8.0%-31.6%). The 0.01% atropine and placebo groups were not significantly different in 2-year cumulative myopia incidence or percentage of patients with fast myopic shift. Photophobia was the most common adverse event and was reported by 12.9% of participants in the 0.05% atropine group, 18.9% in the 0.01% atropine group, and 12.2% in the placebo group in the second year. CONCLUSIONS AND RELEVANCE: Among children aged 4 to 9 years without myopia, nightly use of 0.05% atropine eyedrops compared with placebo resulted in a significantly lower incidence of myopia and lower percentage of participants with fast myopic shift at 2 years. There was no significant difference between 0.01% atropine and placebo. Further research is needed to replicate the findings, to understand whether this represents a delay or prevention of myopia, and to assess longer-term safety. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR-IPR-15006883
RNA editing is a posttranscriptional modification process that alters the RNA sequence so that it deviates from the genomic DNA sequence. RNA editing mainly occurs in chloroplasts and mitochondrial ...genomes, and the number of editing sites varies in terrestrial plants. Why and how RNA editing systems evolved remains a mystery. Ginkgo biloba is one of the oldest seed plants and has an important evolutionary position. Determining the patterns and distribution of RNA editing in the ancient plant provides insights into the evolutionary trend of RNA editing, and helping us to further understand their biological significance.
In this paper, we investigated 82 protein-coding genes in the chloroplast genome of G. biloba and identified 255 editing sites, which is the highest number of RNA editing events reported in a gymnosperm. All of the editing sites were C-to-U conversions, which mainly occurred in the second codon position, biased towards to the U_A context, and caused an increase in hydrophobic amino acids. RNA editing could change the secondary structures of 82 proteins, and create or eliminate a transmembrane region in five proteins as determined in silico. Finally, the evolutionary tendencies of RNA editing in different gene groups were estimated using the nonsynonymous-synonymous substitution rate selection mode.
The G. biloba chloroplast genome possesses the highest number of RNA editing events reported so far in a seed plant. Most of the RNA editing sites can restore amino acid conservation, increase hydrophobicity, and even influence protein structures. Similar purifying selections constitute the dominant evolutionary force at the editing sites of essential genes, such as the psa, some psb and pet groups, and a positive selection occurred in the editing sites of nonessential genes, such as most ndh and a few psb genes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Economic forecasting is a scientific decision-making tool, and it is one of the important basis for the government to formulate economic plans, predict the implementation of the plan, and ...guide the implementation of the plan. Current knowledge about the use of online news in the prediction of economic patterns in China is limited, especially considering the spatio-temporal dynamics over time. This study explored the spatio-temporal patterns of economic output values in Yinzhou, Ningbo, China between 2018 and 2021, and proposed generalized linear model (GLM) and Geographically weighted regression (GWR) model to predict the dynamics using online news data. The results indicated that there were spatio-temporal variations in the economic dynamics in the study area. The online news showed a great potential to predict economic dynamics, with better performance in the GWR model. The findings suggested online news combining with spatio-temporal approach can better forecast economic dynamics, which can be seen as a pre-requisite for developing an online news-based surveillance system The advanced spatio-temporal analysis enables governments to garner insights about the patterns of economic dynamics over time, which may enhance the ability of government to formulate economic plans and to predict the implementation of the plan. The proposed model may be extended to greater geographic area to validate such approach.
The use of Internet-based systems for infectious disease surveillance has been increasingly explored in recent years. However, few studies have used Internet search query or social media data to ...monitor spatial and temporal trends of avian influenza in China. This study investigated the potential of using search query and social media data in detecting and monitoring avian influenza A (H7N9) cases in humans in China. We collected weekly data on laboratory-confirmed H7N9 cases in humans, as well as H7N9-related Baidu Search Index (BSI) and Weibo Posting Index (WPI) data in China from 2013 to 2017, to explore the spatial and temporal trends of H7N9 cases and H7N9-related Internet search queries. Our findings showed a positive relationship of H7N9 cases with BSI and WPI search queries spatially and temporally. The outbreak threshold time and peak time of H7N9-related BSI and WPI searches preceded H7N9 cases in most years. Seasonal autoregressive integrated moving average (SARIMA) models with BSI (β = 0.008, p < 0.001) and WPI (β = 0.002, p = 0.036) were used to predict the number of H7N9 cases. Regression tree model analysis showed that the average H7N9 cases increased by over 2.4-fold (26.8/11) when BSI for H7N9 was > = 11524. Both BSI and WPI data could be used as indicators to develop an early warning system for H7N9 outbreaks in the future.
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