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121.
Abstract

The purpose of the study was to acquire the source and evaluate the risk posed by heavy metals in road dust of steel industrial city (Anshan), Liaoning, Northeast China. Potential ecological risk index (RI), pollution index (PI) and geo-accumulation index (Igeo) were applied to evaluate the heavy metal pollution level, and the carcinogenic risk (RI) and hazard index (HI) were calculated to estimate the human health risk. The geographic information system maps clearly reveal the hot spots of heavy metal spatial distribution. Principle component analysis (PCA) and cluster analysis (CA) classified heavy metals into three groups. The metal Zn and Pb originate from the traffic emission, while Cd, Cr, Fe, Mn, Ni and Sb primarily come from industrial activities. These two pathways were the major source of heavy metals pollution by positive matrix factorization (PMF). The Igeo and PI values of heavy metals were decreased in the following order: Cd?>?Sb?>?Zn?>?Fe?>?Pb?>?Cu?>?Cr?>?Sn?>?Mn?>?Ni. The RI index showed the heavy metals were moderate to very high potential ecological risk. The HI values for children and adults presented a decreasing order of Cr?>?Pb?>?Ni?>?Cu?>?Cd?>?Zn. The HI also predicted a possibility of non-carcinogenic risk for children living in urban areas in comparison with adults.  相似文献   
122.
Estuaries are productive ecosystems providing important habitat for a diversity of species, yet they also experience intense levels of anthropogenic development. To inform decision‐making, it is essential to understand the pathways of impacts of particular human activities, especially those that affect species such as salmon, which have high ecological, social‐cultural and economic values. Salmon systems provide an opportunity to build from the substantial body of research on responses to estuary developments and take stock of what is known. We conducted a systematic English‐language literature review on the responses of juvenile salmon to anthropogenic activities in estuaries and nearshore areas asking: what has been studied, where are the major knowledge gaps and how do stressors affect salmon? We found a substantial body of research (n = 167 studies; 1,369 comparative tests) to help understand responses of juvenile salmon to 24 activities and their 14 stressors. Across studies, 82% of the research was conducted in the eastern Pacific (Oregon and Washington, USA and British Columbia, Canada) showing a limited geographical scope. Using a semiquantitative approach to summarize the literature, including a weight‐of‐evidence metric, we found a range of results from low to moderate–high confidence in the consequences of the stressors. For example, we found moderate–high confidence in the negative impacts of pollutants and sea lice and moderate confidence in negative impacts from connectivity loss and changes in flow. Our results suggest that overall, multiple anthropogenic activities cause negative impacts across ecological scales. However, our results also reveal knowledge gaps resulting from minimal research on particular species (e.g. sockeye salmon), regions (e.g. Atlantic) or stressors (e.g. entrainment) that would be expedient areas for future research. With estuaries acting as a nexus of biological and societal importance and hotspots of ongoing development, the insights gained here can contribute to informed decision‐making.  相似文献   
123.
ObjectiveThe objective of this study is to explore the construction of a digital three-dimensional model of virtual technology that plays an auxiliary role in orthopedic treatment.MethodsThree fracture patients were selected, with no abnormality was observed in bone examination, no musculoskeletal disease in the past; and spiral CT scan of the spine and pelvis, upper limbs, and lower limbs was performed. The virtual technology was used to build a digital 3D model, mainly using the editing software Mimics10.0 software. In addition, the virtual three-dimensional model was verified by virtual surgery, data storage security, work efficiency of the model, model validity, three-dimensional characteristics of the model, the interaction mode of the model, and the data accuracy of the model were studied.ResultsThe digital 3D model was successfully established by Mimics10.0 software. The data fitting efficiency was very high. The data storage security of the 3D model was greatly improved compared with the 2D model, and the work efficiency was improved by at least 50%. There was also a significant change in the accuracy and interaction of data acquisition. Therefore, the detection of digital 3D model work through virtual surgery simulation fully demonstrated the positive auxiliary role of 3D model in orthopedic treatment.ConclusionThe digital 3D model based on Mimics10.0 software is efficient and accurate in obtaining data. It is very effective for subsequent adjuvant therapy in the field of orthopedics, reducing the probability of misdiagnosis by doctors, saving time and improving efficiency, reducing patient's physical pain and unnecessary economic expenses.  相似文献   
124.
Afforestation is considered a cost‐effective and readily available climate change mitigation option. In recent studies afforestation is presented as a major solution to limit climate change. However, estimates of afforestation potential vary widely. Moreover, the risks in global mitigation policy and the negative trade‐offs with food security are often not considered. Here we present a new approach to assess the economic potential of afforestation with the IMAGE 3.0 integrated assessment model framework. In addition, we discuss the role of afforestation in mitigation pathways and the effects of afforestation on the food system under increasingly ambitious climate targets. We show that afforestation has a mitigation potential of 4.9 GtCO2/year at 200 US$/tCO2 in 2050 leading to large‐scale application in an SSP2 scenario aiming for 2°C (410 GtCO2 cumulative up to 2100). Afforestation reduces the overall costs of mitigation policy. However, it may lead to lower mitigation ambition and lock‐in situations in other sectors. Moreover, it bears risks to implementation and permanence as the negative emissions are increasingly located in regions with high investment risks and weak governance, for example in Sub‐Saharan Africa. Afforestation also requires large amounts of land (up to 1,100 Mha) leading to large reductions in agricultural land. The increased competition for land could lead to higher food prices and an increased population at risk of hunger. Our results confirm that afforestation has substantial potential for mitigation. At the same time, we highlight that major risks and trade‐offs are involved. Pathways aiming to limit climate change to 2°C or even 1.5°C need to minimize these risks and trade‐offs in order to achieve mitigation sustainably.  相似文献   
125.
Life cycle assessment (LCA) was combined with primary data from nine forest harvesting operations in New York, Maine, Massachusetts, and Vermont, from 2013 to 2019 where forest biomass (FB) for bioenergy was one of several products. The objective was to conduct a data‐driven study of greenhouse gas emissions associated with FB feedstock harvesting operations in the Northeast United States. Deterministic and stochastic LCA models were built to simulate the current FB bioenergy feedstock supply chain in the Northeast US with a cradle‐to‐gate scope (forest harvest through roadside loading) and a functional unit of 1.0 Mg of green FB feedstock at a 50% moisture content. Baseline LCA, sensitivity analysis, and uncertainty analyses were conducted for three different FB feedstock types—dirty chips, clean chips, and grindings—enabling an empirically driven investigation of differences between feedstock types, individual harvesting process contributions, and literature comparisons. The baseline LCA average impacts were lower for grindings (4.57 kg CO2eq/Mg) and dirty chips (7.16 kg CO2eq/Mg) than for clean chips (23.99 kg CO2eq/Mg) under economic allocation, but impacts were of similar magnitude under mass allocation, ranging from 24.42 to 27.89 kg CO2eq/Mg. Uncertainty analysis showed a wider range of probable results under mass allocation compared to economic allocation. Sensitivity analysis revealed the impact of variations in the production masses and total economic values of primary products of forest harvests on the LCA results due to allocation of supply chain emissions. The high variability in fuel use between logging contractors also had a distinct influence on LCA results. The results of this study can aid decision‐makers in energy policy and guide emissions reductions efforts while informing future LCAs that expand the system boundary to regional FB energy pathways, including electricity generation, transportation fuels, pellets for heat, and combined heat and power.  相似文献   
126.
It is expected that Brazil could play an important role in biojet fuel (BJF) production in the future due to the long experience in biofuel production and the good agro‐ecological conditions. However, it is difficult to quantify the techno‐economic potential of BJF because of the high spatiotemporal variability of available land, biomass yield, and infrastructure as well as the technological developments in BJF production pathways. The objective of this research is to assess the recent and future techno‐economic potential of BJF production in Brazil and to identify location‐specific optimal combinations of biomass crops and technological conversion pathways. In total, 13 production routes (supply chains) are assessed through the combination of various biomass crops and BJF technologies. We consider temporal land use data to identify potential land availability for biomass production. With the spatial distribution of the land availability and potential yield of biomass crops, biomass production potential and costs are calculated. The BJF production cost is calculated by taking into account the development in the technological pathways and in plant scales. We estimate the techno‐economic potential by determining the minimum BJF total costs and comparing this with the range of fossil jet fuel prices. The techno‐economic potential of BJF production ranges from 0 to 6.4 EJ in 2015 and between 1.2 and 7.8 EJ in 2030, depending on the reference fossil jet fuel price, which varies from 19 to 65 US$/GJ across the airports. The techno‐economic potential consists of a diverse set of production routes. The Northeast and Southeast region of Brazil present the highest potentials with several viable production routes, whereas the remaining regions only have a few promising production routes. The maximum techno‐economic potential of BJF in Brazil could meet almost half of the projected global jet fuel demand toward 2030.  相似文献   
127.
The microenvironment plays a major role in conferring chemoresistance to cancer cells. In order to better inform clinical response to chemoresistance, preclinical models that recapitulate its hallmark features are needed to enable screening for resistance‐specific therapeutic targets. A novel platform for seeding cancer cells in 3D hydrogels is presented utilizing derivatives of chitosan and alginate that, critically, is amenable to high throughput screening: cell seeding in hydrogels, media changes, dosing of anticancer compounds, and cell viability assays are all automated using a standard and commercially available liquid handling robot. Culture in these hydrogels elicits resistance in ovarian, lung, and prostate cancer cells to treatment by doxorubicin and paclitaxel. In correlation, proteomics analysis of SKOV3 cells cultured in 3D reveals enrichment of proteins associated with extreme drug resistance including HMOX1 and ALDH2. Subsequently, therapeutic antibodies targeted to tumor‐associated antigens upregulated in 3D cultures are shown to have higher efficacy compared to 2D cultures. Collectively, this automated 3D cell culture platform provides a powerful tool with utility in identification of drugs that may overcome chemoresistance.  相似文献   
128.
Molecular recognition displayed by naturally occurring receptors has continued to inspire new innovations aimed at developing systems that can mimic this natural phenomenon. Since 1930s, a technology called molecular imprinting for producing biomimetic receptors has been in place. In this technology, tailor made binding sites that selectively bind a given target analyte (also called template) are incorporated in a polymer matrix by polymerizing functional monomers and cross‐linking monomers around a target analyte followed by removal of the analyte to leave behind cavities specific to the analyte. The success of the imprinting process is defined by two main figures of merit, that is, the imprinting factor, and selectivity, which are determined by comparing the amount of target analyte or structural analogue bound by the molecularly imprinted polymer (MIP) and the nonimprinted polymer (NIP). NIP is a control synthesized alongside the MIP but in the absence of the template. However, questions arise on whether these figures of merit are reliable measures of the imprinting effect because of the significant differences between the MIP and the NIP in terms of their physical and chemical characteristics. Therefore, this review critically looks into this subject, with a view of defining the best approaches for determining the imprinting effect.  相似文献   
129.
李雪良  钱钧弢  刘金  房峻  陈坚 《生物工程学报》2020,36(11):2241-2249
微小型生物反应器体积微小但在线分析检测和过程控制功能媲美台式装备。其核心支撑技术包括一次性材料及微加工技术、非接触式光学传感器、自动化以及实验设计 (DOE)、数据分析软件与过程控制的整合。由于体积微小、湍流程度和单位能耗较低,微小型反应器内的混合、传质、剪切特性与工业规模设备有一定的区别。现阶段微小型生物反应器主要用于菌株和细胞系筛选和工艺优化,在实现高通量工艺的同时确保了数据的丰度,对缩短研发周期和加速产品上市,尤其是在应对突发性传染性疾病方面有着重要的意义。未来,精准医疗概念的落实也依赖功能柔性化的微小型生物反应器系统。  相似文献   
130.
2011年安徽白鹭洲发现战国时期保存完整的楚国贵族墓葬,因墓主人头发和发簪保存完好、墓主身份显赫而备受关注。该头骨保存完整,具有亚洲蒙古人种的特征,根据骨骼的形态推测其为女性,年龄为35-39岁。为展现该地区战国贵族妇女的容貌、丰富该地区考古多样性提供研究材料。本文首先使用高分辨率CT对该个体的头骨及下颌骨进行了扫描和重建,然后采用基于偏最小二乘回归的颅面复原方法实现生前容貌基本形态的复原。最后,结合考古资料,利用三维模型处理软件对面貌复原模型及其发饰进行了三维建模和纹理贴图等处理,提高了颅面复原模型的真实感,生动形象地再现战国贵族女性面部的形态特征。  相似文献   
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