34 research outputs found
Research on Ecological Corridor Planning of Lanzhou Yuzhong Ecological Innovation City from the Perspective of Ecological Civilization
The practice and research of ecological civilization is a focus of current planning and design, as well as a scientific strategy under the current situation of resource constraint, environmental degradation and ecosystem degradation. Urban elements such as buildings, green land, farmland,water systems and mountains can be connected by ecological corridors into a green ecological system design.At present, many ecological and environmental problems, such as urban heat island effect, fog and haze, automobile exhaust have a negative effect on the construction of social ecological environment. In order to build a new modern city with prosperous economy, beautiful environment and social civilization, scientific and efficient ecological corridors should be designed to improve the environmental quality of the eco-city, and promote the construction and development of ecological civilization and green cities. Based on the relevant research and specific practices of ecological corridors at home and abroad,combine the needs of the planning and construction of the Yuzhong Ecological Innovation City, and discuss on the connotation and characteristics of ecological corridors, and discuss the key elements of ecological corridor planning.This article will take the ecological corridor planning of Yuzhong Eco Innovation City as an example. We design ecological corridor based on field investigation, literature and geographic information system..The planning and design of the ecological corridor in the planning area proposed in this paper can provide positive suggestion on the planning and design of the ecological corridor in other ecological innovation cities
An ENU-Induced Mutation of Nrg1 Causes Dilated Pupils and a Reduction in Muscarinic Receptors in the Sphincter Pupillae
BACKGROUND: N-ethyl-N-nitrosourea (ENU)-induced mutagenesis is a powerful tool for the study of gene function and the generation of human disease models. A large number of mouse mutants obtained by ENU-induced mutagenesis with a variety of phenotypes have been recovered. However, after genetic confirmation testing, only approximately 50% of the abnormal phenotypes were found to be heritable. METHODOLOGY/PRINCIPAL FINDINGS: A mouse mutant, Dp1, with a dilated pupil phenotype was induced with an N-ethyl-N-nitrosourea (ENU) mutagenesis strategy. Sequence analysis for Nrg1 reveals a G>A base substitution that flanks exon E59, encoding for an EGFβ domain, in the 5' splice donor site. The mutation affects but does not abolish the splicing of EGFβ-type Nrg1 mRNA in Dp1 mice and produces several different transcripts by activating other, cryptic splice sites. These types of protein isoforms are expected, and the result shows that, in the mutant, the effect is a decrease in but not an elimination of the high affinity EGFβ-type Nrg1 isoforms. This is partially compensated for by an increase in expression of the low affinity alpha forms or inactive proteins, suggesting that the mutation results in a hypomorphic allele. Interestingly, genetic model testing shows that Dp1 is a mutation that results in a dilated pupil phenotype that is inherited with very low penetrance when heterozygous and with complete penetrance when homozygous. Pharmacological and immunohistochemical tests show a reduction of muscarinic (M) receptors in the sphincter pupillae of Dp1 mice, which is a major cause of dilated pupils. CONCLUSIONS/SIGNIFICANCE: This study is the first report of an Nrg1 mutation being associated with a dilated pupil phenotype and the reduction of M receptors. This report may help in establishing more mutant mouse lines and models of human genetic disease and can be applied to other organisms. Dp1 mice are a valuable resource for the further clarification of Nrg1 biological function
DOX/IL-2/IFN-γ co-loaded thermo-sensitive polypeptide hydrogel for efficient melanoma treatment
Melanoma has been a serious threat to the human health; however, effective therapeutic methods of this cancer are still limited. Combined local therapy is a crucial approach for achieving a superior anti-tumor efficacy. In this paper, a chemo-immunotherapy system of DOX, IL-2 and IFN-γ based on poly(γ-ethyl-L-glutamate)-poly(ethylene glycol)-poly(γ-ethyl-L-glutamate) (PELG-PEG-PELG) hydrogel was developed for local treatment of melanoma xenograft. The drug release process of this system exhibited a short term of burst release (the first 3 days), followed by a long-term sustained release (the following 26 days). The hydrogel degraded completely within 3 weeks without obvious inflammatory responses in the subcutaneous layer of rats, showing a good biodegradability and biocompatibility. The DOX/IL-2/IFN-γ co-loaded hydrogel also showed enhanced anti-tumor effect against B16F10 cells in vitro, through increasing the ratio of cell apoptosis and G2/S phage cycle arrest. Moreover, the combined strategy presented improved therapy efficacy against B16F10 melanoma xenograft without obvious systemic side effects in a nude mice model, which was likely related to both the enhanced tumor cell apoptosis and the increased proliferation of the CD3+/CD4+ T-lymphocytes and CD3+/CD8+ T-lymphocytes. Overall, the strategy of localized co-delivery of DOX/IL-2/IFN-γ using the polypeptide hydrogel provided a promising approach for efficient melanoma therapy
The complete mitochondrial genome of common greenshank Tringa nebularia
The complete mitochondrial genome of Common Greenshank Tringa nebularia was obtained using next-generation sequencing. The circular genome was 16,682 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a control region. The overall nucleotide composition was A: 31.8%, T: 24.9%, C: 29.8%, and G: 13.4%. Nine genes were encoded on the light strand, and the remaining 28 genes were encoded on the heavy strand. Most of the PCGs began with the ATG as the start codon, and four kinds of termination codons were used in this mitogenome. This study improves our understanding of the mitogenomic characteristics and its phylogenetic relationships within Charadriiformes
A Visual Salience Model of Landmark Based on Virtual Geographical Experiments
In this paper,a visual salience model of landmark based on virtual geography experiments is proposed for landmark discrimination and salience calculation.Taking the calculation of salience model of city buildings as an example,visual factors of landmarks and their calculation are first analyzed,and then a virtual experiment environment is developed to incorporate eye tracking as well as controllable and computable visual factors.Furthermore,a quantitative model of the relationship between eye movement factors and visual salience of landmark is derived from empirical results.Based on the quantitative model,further experiment is designed to solve the equation of visual salience model of landmark by fitting experimental data,which describes the relationship between a visual salience of landmark and visual factors.The key to the proposed method is to use eye movement factors to represent a salience model in a virtual environment with controllable and computable visual factors,and then the salience model can be calculated through landmark cognition experiments and data analysis.This method can not only reduce the complexity of landmark research,but also overcome the difficulty of repeating the experiments,which makes it a unique advantage to solve problem that tackles interaction mechanism between human and environments such as landmark discrimination
Variation Characteristics of Stable Isotopes in Precipitation and Response to Regional Climate Conditions during Pre-monsoon, Monsoon and Post-monsoon Periods in the Tianshui Area
The stable isotopes in precipitation provide a new understanding for the mechanism study of water cycles in the Loess Plateau. However, there has never been an introduction for the Tianshui area, which is transitioning from semi-humid to semi-arid. We analyzed the time series changes of stable isotopes in precipitation at seven sampling points during pre-monsoon, monsoon and post-monsoon periods (April to October) in the Tianshui area. The results show that the temperature effect not only shows spatial differences but also seasonal changes and a weak precipitation effect is only found during the monsoon period. At the same time, the variation characteristics of precipitation isotopes before and after the monsoon clearly record the advancing and retreating time of the monsoon. We captured this important time node around 7 May and 21 September. Due to the influence of the regional microclimate formed by different natural conditions, the kinetic fractionation effect of isotopes in precipitation cause obvious differences in the slope and intercept of the meteoric water line in different natural regions, which shows that the stable isotopes in precipitation with high-resolution changes in a short period of time are of great significance to deeply explore the hydrological process of regional microclimates
A Stable Isotope Approach for Estimating the Contribution of Recycled Moisture to Precipitation in Lanzhou City, China
The proportional contribution of recycled moisture to local precipitation is a geographically dependent parameter that cannot be ignored in water budgets. Stable hydrogen and oxygen isotopes are sensitive to environmental changes and can be applied to investigate the modern water cycle. In this study, a three-component mixing model is used to calculate the contribution of different water vapors (advection, evaporation and transpiration) to summer precipitation in Lanzhou city, Northwest China. The results show that for all sampling sites in Lanzhou, the contribution of advection vapor to precipitation is the largest, followed by the plant transpiration vapor, and the contribution of surface evaporation water vapor is usually the least, with the average values of 87.96%, 9.1% and 2.9%, respectively. The spatial differences of plant transpiration vapor are generally larger than those of advection vapor and surface evaporation vapor, and the high values appear in Yongdeng, Daheng and Gaolan
Chemical Reaction Spectrum: A Holographic Image for Characterizing Multi-component Chemical Mixtures
Abstract: Multi-component chemical mixtures (MCMs) and their various effects always concerned in analytical chemistry, but current analytical techniques based on test-tube experiments often involves many high-cost and laborious operations. Today’s pop machine-learning (ML) technology has exhibited their successes in dealing with the analysis task of various complex systems. Predictably, the introduction of ML will radically accelerate the exploration of many fields involving mixture analysis. But the biggest challenge ahead for this process is how to provide some intelligible and sufficient data for various algorithms. In this study, we proposed a chemical imaging strategy to visualize various mixtures as some feature images by using ink-jet printing technology based on combinatorial chemistry. Here, these feature images were as a novel data form of chemical reaction spectrum (CRS), which can comprehensively describe and record the reaction characteristics of the complex sample. Compared with common imaging methods, the CRS with high-throughput chemical reaction dots is an efficient and economic information visualization way for the MCM sample. It is expected to be an important data acquisition approach for the application of ML in the field of chemistry in future
Stable Isotope Ratios in Tap Water of a Riverside City in a Semi-Arid Climate: An Application to Water Source Determination
Stable isotopes (e.g., δ2H and δ18O) in tap water are important tools to understand the local climate or environment background, water sources and the state of regional water supply. Based on 242 tap water samples, 35 precipitation samples and 24 surface water samples gathered in the urban area of Lanzhou, the basic spatiotemporal characteristics of isotopes in tap water, their connection with isotopes in other water bodies and change during the process from raw water to tap water are discussed in detail, combining the information of local tap water supply and water source. It can provide reliable help for understanding the isotope characteristics of local tap water, regional water supply management and determination of tap water source of in a small area. Except for the establishment of a new data set of isotopes in tap water with complete time series and uniform spatial distribution of sampling sites, other results show that: (1) The Local Tap Water Line (LTWL) of Lanzhou is δ2H = (6.03 ± 0.57) δ18O + (−8.63 ± 5.44) (r2 = 0.41, p < 0.01). (2) For seasonal variations, δ2H and δ18O in tap water both are higher in autumn and lower in spring. The diurnal and daily variations of isotopes in tap water are not large. As for spatial variations, the monthly mean values of δ2H and δ18O in tap water at each sampling site show little difference. The isotopes in tap water collected from one single sampling site can be considered as a representative for isotopes in tap water in the area with a single tap water source. (3) Isotopes in tap water show weak connection with precipitation isotopes, but exhibit good connection (consistent seasonal variation, similar numerical range, small numerical difference and high correlation) with isotopes in surface water, which is the direct water source. Isotopes in water change little from raw water to tap water. Isotopic composition of tap water in Lanzhou can be used as a representative of isotopes in surface water