The coalescence of two droplets with unequal lengths through a head-to-rear collision in the microchannel with a double T-junction is an important passive method to construct droplet reactors. However, the accurate prediction of the coalescence position is still not achievable. This work aimed to explore the coalescence position by analyzing the droplet dynamics. Firstly, the velocity variation of the paired droplets moving in a straight microchannel was analyzed to divide the whole process into several stages. Then, based on the experimental investigations, mathematical models were developed to describe the distances of the droplet-pairs moving in each stage to predict the coalescence position in the straight microchannel. In addition, the coalescence position, as well as the coalescence mechanism, was analyzed for the paired droplets in an expansion microchannel to explore the more possibilities of intensifying the construction of droplet reactors in microchannels.

中国式现代化是人口规模巨大条件下实现全体人民共同富裕的现代化,中国新型城镇化战略推进过程中,中西部地区农业转移人口的家庭功能与可持续发展问题需要重点关注.通过梳理新型城镇化发展的问题,发现新型城镇化面临少子老龄化与性别失衡的人口态势、日趋明显的家庭化迁移趋势、不断弱化的家庭功能、外部风险频发的宏观环境、严重滞后且情况复杂的中西部城镇化发展现状等挑战.将加强以家庭成员就业为代表的经济功能,以婚姻、生育、抚幼和养老为代表的非经济功能作为核心研究问题,提出包括以人为核心的新型城镇化理论与态势研究、农业转移人口家庭经济功能与生计转型、农业转移人口家庭非经济功能与家庭发展、县域新型城镇化进程中的政策响应及成本测算与优化等重点内容在内的多学科交叉研究框架.未来研究新型城镇化应体现微观研究与宏观研究相结合、定性研究与定量研究相结合、静态研究与动态研究相结合、理论研究与政策研究相结合.

利用2018年"中国家庭追踪调查"相关数据,分析同胞数量和结构对现阶段中国家庭教育投入的影响.研究发现,家庭教育投入在不同个体以及家庭存在明显不同.同胞数量对各项家庭教育投入均具有显著负面影响,且在不同个体及不同家庭存在明显差异.在二孩家庭中,同胞结构对各项家庭教育投入具有显著影响,与有长姐的儿童相比,有年龄接近哥哥的儿童得到的金钱投入明显更少;但有年龄接近弟弟的儿童,得到的时间投入明显更多,"长姐效应"没有得到验证.对多子女家庭、尤其是二孩家庭的教育投入状况的研究,有助于理解当代中国家庭内部的教育资源分配特征及教育投入的代内公平问题.

为应对人口老龄化与低生育率,国家提倡一对夫妻可以生育三个子女并将婚嫁、生育、养育、教育一体考虑,因此完善家庭抚幼功能迫在眉睫.本文基于2021年陕西N县城乡家庭专项调查数据,运用多元线性回归分析与多分类回归分析等方法,分析西部典型农业县中家庭人口禀赋对夫妻抚幼投入与分工的影响.研究发现城乡女性在家庭抚幼中依然占据绝对主导地位,男性参与度较差,农村男性尤甚;伴随家庭抚幼负担加重,仅妻子的抚幼投入增加,"父职"缺位明显;祖辈健康状况越好,对家庭抚幼的帮助效应越显著;作为家庭的刚性需求,抚幼功能表现出较强的稳定性,家庭养老负担的增加并未对家庭抚幼产生挤占效应;县外流动的打工经历明显削弱了夫妻的抚幼投入.研究揭示了西部县域家庭抚幼功能发挥面临的诸多阻力,为进一步发挥与完善西部县域家庭功能,须持续关注家庭内部两性分工的科学性与平等性,促进教育体系改革,提升西部地区男性受教育程度,强化其个体资源与家庭责任意识,促进就地城镇化,避免远距离流动带来的家庭离散,保障西部地区家庭抚幼功能与儿童成长权益.

(1) Aims: This paper aims to analyze the factors affecting children’s mental health during home quarantine from the perspective of family composition in a specific Chinese context where historically, families are small in size. (2) Methods: Here, 10,210 online questionnaires from 3 junior high schools in Xi’an and Hanzhong from 23 to 27 February 2020, were collected to explore the impact of family factors on children’s mental health in Northwest China during home quarantine based on the ecosystem theory, by using OLS, logit regression models, and the Shapley value decomposition method. (3) Results: The mental health of northwestern Chinese children changed significantly after home quarantine. We also found that during home quarantine, some factors, such as a high-income family, lack of siblings, living with parents, mothers with middle- or high-level occupations, frequent parent–child communication, and better parent–child relationships, were positively related to children’s mental health. (4) Conclusions: Different from previous studies, this paper found that the psychological condition of children in Northwest China tended to be improved during the epidemic. In addition, family factors, especially the parent–child interaction, played an important role in the mental health of children during the epidemic.

National parks, as an important type of nature protected areas, are the cornerstone that can effectively maintain biodiversity and mitigate global climate change. At present, China is making every effort to build a nature-protection system, with national parks as the main body, and this approach considers China′s urgent goals of obtaining carbon neutrality and mitigating climate change. It is of great significance to the national carbon-neutralization strategy to accurately predict the carbon sink capacity of national park ecosystems under the background of global change. To evaluate and predict the dynamics of the carbon sink capacity of national parks under climate change and different management measures, we combined remote-sensing observations, model simulations and scenario analyses to simulate the change in the carbon sink capacity of the proposed Kunlun Mountain National Park ecosystem over the past two decades (2000–2020) and the change in the carbon sink capacity under different zoning controls and various climate change scenarios from 2020 to 2060. Our results show that the carbon sink capacity of the proposed Kunlun Mountain National Park area is increasing. Simultaneously, the carbon sink capacity will be improved with the implementation of park management and control measures; which will be increased by 2.04% to 2.13% by 2060 in the research area under multiple climate change scenarios. The research results provide a scientific basis for the establishment and final boundary determination of the proposed Kunlun Mountain National Park.

基于2021年陕西N县儿童生存与发展调查数据,通过构建多分类逻辑回归模型分析家庭人口禀赋对中国农村已婚女性劳动参与的影响.结果显示:相比于男性群体,家庭人口禀赋对农村已婚女性劳动参与的影响更强,子女年龄和配偶家务支持有正向影响,向父辈的家务支持有负向影响;家庭人口禀赋对已婚女性劳动参与的影响效应在不同流动经历群体间存在差异,女性的近期流动和县外流动均会增加其劳动参与的概率,而配偶的流动距离则会负向降低其劳动参与的可能性.据此,释放性别红利、促进农村已婚女性参与劳动,要因地制宜、因人而异地拓宽个体就业选择,从增强家庭人口禀赋着手,充分发挥配偶与社会力量,创新养老与抚幼方式,宣传正确的性别角色观念,营造公平竞争的劳动环境.

在快速城镇化背景下,中国农民工家庭的代际关系也处在不断变迁中.本文利用2018年"百村调查"数据,使用潜在类别分析方法,发现农民工家庭存在紧密型、传统型、接受型、亲近型和疏离型等五种代际关系类型,传统农村家庭代际关系已经衍生发展出多种类型.其中,男性农民工更容易与父母产生紧密型或接受型关系,女性农民工更可能与父母有亲近型、传统型、疏离型关系;而新一代农民工更容易与父母产生紧密型、接受型、亲近型关系,老一代农民工更可能与父母有传统型或疏离型关系.同时,人口流动特征对农民工家庭代际关系的影响存在性别与代次差异,异地流动的男性农民工和新一代农民工与父母形成疏离型关系的可能性较低,但对女性农民工和老一代农民工的疏离型家庭代际关系具有显著正向影响.

农业转移人口在城镇化中的角色举足轻重,推进农业转移人口市民化有利于新型城镇化发展目标的高质量实现.土地承载着物质保障和情感依附功能,是农业转移人口留置于农村最重要的资源.生计资本是生计活动的基础,是在城镇稳定居住的决策基础,也是农地政策对农村家庭禀赋提升的结果.因此,农地政策作为生计系统的外部因子对于市民化决策的影响可能隐含着"农地政策回应→生计资本→市民化意愿"这一因果链条.本文采用11个省份开展的"全国百村农业转移人口调查"数据,分析了农业转移人口农地政策回应、生计资本现状及市民化意愿选择之间的关系,探索农地政策回应、生计资本影响市民化的具体路径,最终得出结论并提出对策建议.研究发现:(1)农业转移人口对农地政策回应程度较高,农地流转参与经历对于市民化选择有较强的促进作用.(2)多数农业转移人口具有定居城镇的意愿,自然资本发挥推力作用,社会资本、物质资本、金融资本拉力作用显著.(3)在农地政策回应、生计资本与市民化意愿的影响机制上,农地政策回应通过促进农业转移人口社会资本、物质资本、人力资本对市民化产生正面影响.研究的可能性贡献在于证明了政策回应、生计资本和市民化之间的因果链条;强调了农地政策在推行过程中要及时关注政策执行细节及反馈,适当的政策引导将保障低生计资本群体的发展权利,促进高生计资本群体的城镇生活取向;提出农地政策、农村人力资本开发和住房政策之间需要进行有效的契合,以更好地弥合农业转移人口市民化过程中"不想"和"不能"之间的差距.

Inflammatory bowel diseases (IBD) are kind of recurrent inflammatory issues that occur in the gastrointestinal tract, and currently clinical treatment is still unideal due to the complex pathogenesis of IBD. Basically, gut barrier dysfunction is triggered by gut microbiota dysbiosis that is closely associated with the development of IBD, we thus investigated the therapeutic capacity of berberine (BBR) to improve the dysregulated gut microbiota, against IBD in rats, using a combinational strategy of targeted metabolomics and 16 s rDNA amplicon sequencing technology. Expectedly, our data revealed that BBR administration could greatly improve the pathological phenotype, gut barrier disruption, and the colon inflammation in rats with dextran sulfate sodium (DSS)-induced colitis. In addition, 16S rDNA-based microbiota analysis demonstrated that BBR could alleviate gut dysbiosis in rats. Furthermore, our targeted metabolomics analysis illustrated that the levels of microbial tryptophan catabolites in the gastrointestinal tract were significantly changed during the development of the colitis in rats, and BBR treatment can significantly restore such changes of the tryptophan catabolites accordingly. At last, our in vitro mechanism exploration was implemented with a Caco-2 cell monolayer model, which verified that the modulation of the dysregulated gut microbiota to change microbial metabolites coordinated the improvement effect of BBR on gut barrier disruption in the colitis, and we also confirmed that the activation of AhR induced by microbial metabolites is indispensable to the improvement of gut barrier disruption by BBR. Collectively, BBR has the capacity to treat DSS-induced colitis in rats through the regulation of gut microbiota associated tryptophan metabolite to activate AhR, which can greatly improve the disrupted gut barrier function. Importantly, our finding elucidated a novel mechanism of BBR to improve gut barrier function, which holds the expected capacity to promote the BBR derived drug discovery and development against the colitis in clinic setting.

With the population aging and urbanization in China, vulnerable older adults tend to show more complex characteristics, bringing great challenges to public health policies. Using China Longitudinal Aging Social Survey data 2014, this paper builds a comprehensive index system for the identification of vulnerable older adults from three dimensions, including health, economy, and social support, then divides older adults into four support levels and six small classes by using the typological method. The results show that older adults in urgent need of assistance or priority are those poor in health and economic conditions, 1.46% of them are highly vulnerable because of the lack of social support; 12.76% of them obtain a certain social support are moderately vulnerable; and 34.72% of them are slightly vulnerable with disadvantage in only one dimension. The geographic distribution of different types of vulnerable older adults varies significantly. The paper provides evidence to design more feasible and specific policies with comprehensive considerations for different types of vulnerable older adults residing in different regions.

Structural balance in fully signed networks consisting of both individual attributes and social interactions has great importance on social computing, but its sociological or physical mechanisms still need further exploration, and its measurement is still lacking. In this article, we discuss the new mechanism of balance theory and design a new energy function to measure the global structural balance. An optimization algorithm that minimizes the energy function to detect the communities in structural balance is proposed as well, and experiment results show the excellent effectiveness and efficiency of our proposed method. An application on the investigated data from Shenzhen, China, is also provided to explain the social significance of structural balance.

Nowadays, the research on the recognition and separation of proteins has attracted extensive attention in the fields of materials science, bioengineering and life science. Protein imprinted polymers are ideal recognition materials, due to its high selectivity, good stability, easy preparation, and low cost. Herein, novel surface imprinting biowaste-derived molecularly imprinted polymers (BD-MIPs) were synthesized for specific recognition and purification of lysozyme (Lyz). This is the first time that magnetic pomegranate rind-derived carbon was used as a carrier to immobilize Lyz. Then, with the self-polymerization of dopamine, a large number of biocompatible recognition sites were generated under mild conditions. The physical/chemical properties and surface morphologies of the synthetic BD-MIPs were characterized, indicating that the imprinted film was successfully synthesized, and the BD-MIPs had good thermal stability and magnetic property. To investigate the recognition performance of BD-MIPs, four adsorption experiments were performed. The results show that BD-MIPs had a high adsorption capacity of 301.87 mg g(-1), fast equilibrium time within 40 min, satisfactory selectivity and good reusability for Lyz. Furthermore, the practicability of BD-MIPs was confirmed by the isolation of Lyz from a biological sample. The good adsorption capacity and gentle one-step preparation make the BD-MIPs attractive for Lyz recognition, which shows potential values in basic biomedical research, industrial protein purification and clinical diagnostics.

本文借鉴消费者信任-行动理论,利用2013年深圳P区的农民工调查数据,从公众信任视角切入,从政府信任和人员信任两个维度对农民工公共服务参与影响因素进行研究.研究发现:农民工对于流入地政府的总体信任对其积极主动参与公共服务具有显著的正向影响;同时,农民工对于流入地政府工作人员的信任水平越高,公共服务参与率越高;而农民工对流入地政府机构的不同信任水平对其参与公共服务均不存在显著影响.研究对于提升新型城镇化背景下公共服务均等化,引导农民工有序参与流入地公共服务,进而推进"以人为本"城镇化发展有积极的指导意义.

基于可持续生计框架与生计恢复力理论框架,结合就地就近城镇化背景下农民工的个体特征,建立农民工生计恢复力指标体系.采用主成分分析法对指标赋权,使用一手调查数据定量测算生计恢复力,分析发现:农民工生计恢复力总体偏低,整体弹性大;各项生计恢复力差异较大,内部优化尚有待发展;学习能力总体来说较强,但技能培训、教育程度对于农民工生计恢复力来说是明显短板;男性农民工、老一代农民工和在经济水平较好县域工作的农民工生计恢复力较强,在不同维度表现形式存在差异.政策制定应着眼于全面增强农民工缓冲能力、自组织能力、学习能力,针对不同恢复力维度提升政策扶持力度,增强农民工生计的恢复力.

如何在新型城镇化背景下"因城施策"保证农民工"住有所居"是亟待回答的重要问题.基于4787个实地调查样本,针对东部大型城市和中西部中小城镇、 人口异地城镇化和就地就近城镇化的农民工,分代次讨论其居住意愿和购房能力,发现:农民工已具备一定的购房意愿基础和购房能力,但不同城镇和代次之间具有异质性;大城市周边的农民工青睐在大城市租住"小而精"的房屋,中小城镇的农民工倾向于就地就近购买家乡周边县城的"大面积"住房;经济因素是造成不同代次农民工居住意愿差异的首要因素,地域文化和家庭因素构成次要影响;第一代农民工城市购房可能性和可行性较小,第二代农民工是当前住房购买的主力军,第三代农民工是未来中西部地区房地产去库存的潜力所在.据此,从"因城施策、 分批推进、 政策联动、 营造环境"四个方面提出政策建议.

Nowadays, the abuse of antibiotics in aquaculture has generated considerable problems for food safety. Therefore, it is imperative to develop a simple and selective method for monitoring illegal use of antibiotics in aquatic products. In this study, a method combined molecularly imprinted membranes (MIMs) extraction and liquid chromatography was developed for the selective analysis of cloxacillin from shrimp samples. The MIMs was synthesized by UV photopolymerization, and characterized by scanning electron microscope, Fourier transform infrared spectra, thermo-gravimetric analysis and swelling test. The results showed that the MIMs exhibited excellent permselectivity, high adsorption capacity and fast adsorption rate for cloxacillin. Finally, the method was utilized to determine cloxacillin from shrimp samples, with good accuracies and acceptable relative standard deviation values for precision. The proposed method was a promising alternative for selective analysis of cloxacillin in shrimp samples, due to the easy-operation and excellent selectivity.

基于可持续生计框架,结合就地就近城镇化背景下农民工的个体特征,建立可持续生计评价指标体系;采用层次分析法(AHP)对指标赋权,使用一手调查数据定量测算生计资本,通过多维视角比较分析发现:就地就近城镇化有利于农民工生计资本改善,但生计资本内部依然存在优化空间;当前人力和物质资本最为丰富,但教育、职业培训和住房面积是其短板;自然资本水平较低,土地盘活是关键;社会资本的有效提高,将协同解决金融资本借贷帮助问题;资本弹性区间与指标权重对农民工未来生计提升较为重要,而政策制定需重点注意农民工群体内的差异.据此,提出培育农民工生计资本的对策建议.

Estrone molecularly imprinted polymers were synthesized through the self-polymerization of dopamine on the surface of silica gels, which had the characteristics of mild polymerization conditions, simple reaction procedure and good specific recognition ability for estrone. The estrone molecularly imprinted polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis and nitrogen adsorption-desorption tests. The characterization confirmed that the imprinted polymers were successfully grafted on the surface of silica gels. Through investigating the adsorption performance, the prepared estrone molecularly imprinted polymers exhibited high adsorption capacity, fast mass transfer, as well as excellent selectivity toward estrone. The estrone molecularly imprinted polymers as the solid-phase extraction adsorbent coupled with high-performance liquid chromatography was developed to determine estrone from the milk samples. The developed estrone molecularly imprinted polymer solid-phase extraction with high-performance liquid chromatography method exhibited satisfactory specificity, precision, accuracy and good linearity relationship in the range of 0.2-20 μg/mL. The developed method is simple, fast, effective and high specificity method and it provides a new method to detect the residues of estrone in animal foods.

Dexamethasone-imprinted polymers were fabricated by reversible addition-fragmentation chain transfer polymerization on the surface of magnetic nanoparticles under mild polymerization conditions, which exhibited a narrow polydispersity and high selectivity for dexamethasone extraction. The dexamethasone-imprinted polymers were characterized by scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive spectrometry, and vibrating sample magnetometry. The adsorption performance was evaluated by static adsorption, kinetic adsorption and selectivity tests. The results confirmed the successful construction of an imprinted polymer layer on the surface of the magnetic nanoparticles, which benefits the characteristics of high adsorption capacity, fast mass transfer, specific molecular recognition, and simple magnetic separation. Combined with high-performance liquid chromatography, molecularly imprinted polymers as magnetic extraction sorbents were used for the rapid and selective extraction and determination of dexamethasone in skincare cosmetic samples, with the accuracies of the spiked samples ranging from 93.8 to 97.6%. The relative standard deviations were less than 2.7%. The limit of detection and limit of quantification were 0.05 and 0.20 μg/mL, respectively. The developed method was simple, fast and highly selective and could be a promising method for dexamethasone monitoring in cosmetic products.