Ecological effect of urban spatial expansion in river valleys: A case study in the main urban area of Lanzhou City

[Objective] The ecological effect of urban spatial expansion is the key problem of human-environment relationship in the process of urbanization. It is of great significance to explore the complex scientific problem of ecological effect caused by urban spatial expansion from multiple angles to promote the sustainable and high-quality development of urban and ecological space. [Methods] Taking the main urban area of Lanzhou City in China as an example, this study calculated the scale, intensity, and landscape pattern indices of urban spatial expansion in 1995, 2005, 2015, and 2020 to reflect the spatiotemporal variation characteristics of urban spatial expansion in the city from 1995 to 2020, and divided the research area into 12184 grids. Using the spatial principal component analysis method, atmospheric radiation transfer equation method, and revised ecosystem service value estimation model, this study analyzed the ecological risk effect, heat island effect, and ecosystem service effect of urban spatial expansion from various angles, and discussed the impact of natural environment conditions on the ecological effect of urban spatial expansion of cities in river valleys. [Results] The results show that from 1995 to 2020, the scale and intensity of urban expansion in Lanzhou City have increased, the fragmentation of urban landscape has decreased, urban expansion has mainly occurred in the western and northern parts of the city, and the urban expansion mode has changed from group expansion to leaping expansion. The overall ecological risk effect and heat island effect in the city have shown a weakening trend, but a rising trend was observed in the river valley, and the overall pattern of effects has been characterized by high in the valley and low at the peripheries. There is a slight improvement in the ecosystem service effect, which mainly shows that the ecosystem service value in the surrounding areas of the river valley has improved significantly, and some areas in the built-up area have changed from low-value area to medium-value area. Urban expansion negatively affects the natural substrates of the region, while the natural substrates also affects the scale, direction, and mode of urban expansion. Coordinating the relationship between the two is essential for the sustainable and harmonious development of human beings and nature. [Conclusion] The research framework of ecological effects of urban spatial expansion was constructed from multiple perspectives. Urban spatial expansion has a significant impact on ecological risk, heat island, and ecosystem service effects at the grid scale, which provides a new way of quantitative visualization of the dynamic relationships between urban evolution and ecological environment

A method to prolong lithium-ion battery life during the full life cycle

Extended lifetime of lithium-ion batteries decreases economic costs and environmental burdens in achieving sustainable development. Cycle life tests are conducted on 18650-type commercial batteries, exhibiting nonlinear and inconsistent degradation. The accelerated fade dispersion is proposed to be triggered by the evolution of an additional potential of the anode during cycling as measured vs. Li$^+$/Li. A method to prolong the battery cycle lifetime is proposed, in which the lower cutoff voltage is raised to 3 V when the battery reaches a capacity degradation threshold. The results demonstrate a 38.1% increase in throughput at 70% of their beginning of life (BoL) capacity. The method is applied to two other types of lithium-ion batteries. A cycle lifetime extension of 16.7% and 33.7% is achieved at 70% of their BoL capacity, respectively. The proposed method enables lithium-ion batteries to provide long service time, cost savings, and environmental relief while facilitating suitable second-use applications

Mutagenicity of Chinese traditional medicine Semen Armeniacae amarum by two modified Ames tests

<p>Abstract</p> <p>Background</p> <p>Semen armeniacae amarum (SAA) is a Chinese traditional medicine and has long been used to control acute lower respiratory tract infection and asthma, as a result of its expectorant and antiasthmatic activities. However, its mutagenicity <it>in vitro </it>and <it>in vivo </it>has not yet been reported. The Ames test for mutagenicity is used worldwide. The histidine contained in biological samples can induce histidine-deficient cells to replicate, which results in more <it>his</it>⁺colonies than in negative control cells, therefore false-positive results may be obtained. So, it becomes a prerequisite to exclude the effects of any residual histidine from samples when they are assayed for their mutagenicity. Chinese traditional herbs, such as SAA, are histidine-containing biological sample, need modified Ames tests to assay their <it>in vitro </it>mutagenicity.</p> <p>Methods</p> <p>The mutagenicity of SAA was evaluated by the standard and two modified Ames tests. The first modification used the plate incorporation test same as standard Ames teat, but with new negative control systems, in which different amounts of histidine corresponding to different concentrations of SAA was incorporated. When the number of his⁺revertants in SAA experiments was compared with that in new negative control, the effect of histidine contained in SAA could be eliminated. The second modification used a liquid suspension test similar to the standard Ames test, except with histidine-rich instead of histidine-limited medium. The aim of this change was to conceal the effect of histidine contained in SAA on the final counting of <it>his</it>⁺revertants, and therefore to exclude false-positive results of SAA in the Ames test. Furthermore, the effect of SAA on chromosomal aberration in mammalian bone marrow cells was tested.</p> <p>Results</p> <p>The standard Ames test showed a positive result for mutagenicity of SAA. In contrast, a negative response was obtained with the modified plate incorporation and modified suspension Ames tests. Moreover, no apparent chromosomal aberrations were observed in mammalian bone marrow cells treated with SAA.</p> <p>Conclusion</p> <p>The standard Ames test was not suitable for evaluating the mutagenicity of SAA, because false-positive result could be resulted by the histidine content in SAA. However, the two modified Ames tests were suitable, because the experimental results proved that the effect of histidine in SAA and therefore the false-positive result were effectively excluded in these two modified Ames tests. This conclusion needs more experimental data to support in the future. Moreover, the experimental results illustrated that SAA had no mutagenicity <it>in vitro </it>and <it>in vivo</it>. This was in agreement with the clinical safety of SAA long-term used in China.</p

Identification of the Virtual Organization Breeding Environment Based on the Cooperation Network

Part 19: Identification of PatternsInternational audienceCurrent studies argue that through building the virtual organization breeding environment one can quickly find partners and create a virtual enterprise. The creation of the virtual organization breeding environment requires its own social capital to satisfy some social requirements, but such researches are few This paper, based on complex network theory, proposes a new method to identify the virtual organization breeding environment, which consists of four steps: first is to build the cooperation network from the history of cooperation between enterprises, then is to translate social requirements of the virtual organization breeding environment into structural characteristics, next is to establish the problem model, and final is to design the algorithm of searching for sub-networks (namely virtual organization breeding environments) in the cooperation network, which must meet specific structural characteristics. The proposed method in this paper is based on practical cooperation networks, and therefore is a good guidance to the creation of the virtual organization breeding environment

A Predefined-Time Control for the Laser Acquisition in Space Gravitational Wave Detection Mission

The establishment of a laser link between satellites, i.e., the acquisition phase, is a key technology for space-based gravitational detection missions, and it becomes extremely complicated when the long distance between satellites, the inherent limits of the sensor accuracy, the narrow laser beam divergence and the complex space environment are considered. In this paper, we investigate the laser acquisition problem of a new type of satellite equipped with two two-degree-of-freedom telescopes. A predefined-time controller law for the acquisition phase is proposed. Finally, a numerical simulation was conducted to demonstrate the effectiveness of the proposed controller. The results showed that the new strategy has a higher efficiency and the control performance can meet the requirements of the gravitational detection mission

Decreased circulating dipeptidyl peptidase-4 activity after short-term intensive insulin therapy predicts clinical outcomes in patients with newly diagnosed type 2 diabetes

BackgroundThis study aims to investigate the changes in circulating dipeptidyl peptidase-4 (DPP-4) activity following short-term intensive insulin therapy (SIIT) in newly diagnosed type 2 diabetes (T2D) patients and to assess its potential in predicting long-term remission.MethodsNinety-five patients underwent SIIT for 2-3 weeks to attain and sustain near-normal glycemia. Insulin was then discontinued, and patients were followed for a year to evaluate glycemic outcomes. Biochemical tests, serum DPP-4 activity, and mixed meal tolerance tests were conducted at baseline, post-SIIT, and the 3-month follow-up.ResultsDPP-4 activity decreased from 44.08 ± 9.58 to 40.53 ± 8.83 nmol/min/mL after SIIT (P&lt;0.001). After three months post-SIIT, DPP-4 activity remained stable in the remission group (39.63 ± 8.53 nmol/L) but increased in the non-remission group (42.34 ± 6.64 nmol/L). This resulted in a more pronounced decrease in DPP-4 activity from baseline in the remission group (-3.39 ± 8.90 vs. -1.10 ± 8.95, P = 0.035). Logistic regression analyses showed that patients with greater DPP-4 activity reduction had a higher likelihood of 1-year remission (70% vs. 51.1%, OR: 7.939 [1.829, 34.467], P = 0.006 in the fully adjusted model). A non-linear relationship between △DPP-4 and 1-year remission rate was observed, with a clear threshold and saturation effect.ConclusionCirculating DPP-4 activity significantly decreases after SIIT. The change in circulating DPP-4 activity during the 3-month post-treatment phase has the potential to predict long-term remission