基于壳聚糖的吸附材料在六价铬吸附中的应用

铬作为在工业中广泛使用的一种过渡金属,具有重要的应用价值,但过量的铬会污染水和土壤,危害环境和人类健康。其中,六价铬是铬的氧化态中毒性最高的一种,利用吸附的方法将六价铬从污染水中去除是消除水体中铬污染的一种重要方法,而开发简单高效且不产生二次污染的吸附材料对六价铬进行去除十分必要。壳聚糖作为一种优良的天然绿色生物材料,具有良好的生物相容性和可降解性,近年来广泛被用于六价铬的吸附。由于单纯的壳聚糖存在酸性不稳定性、吸附位点不足等缺点,利用壳聚糖分子链中的氨基和羟基官能团对其进行改性和复合,可以生成更为稳定的改性壳聚糖,并显著提升其对六价铬的吸附能力。文中详细介绍了近年来报道的壳聚糖化学改性和复合改性的2种方法,以及其对六价铬的吸附性能的影响,并探讨了六价铬的吸附机理及其主要影响因素。

A high-quality chromosome-level genome assembly reveals genetics for important traits in eggplant

Eggplant(Solanum melongena L.)is an economically important vegetable crop in the Solanaceae family,with extensive diversity among landraces and close relatives.Here,we report a high-quality reference genome for the eggplant inbred line HQ-1315(S.melongena-HQ)using a combination of Illumina,Nanopore and 10X genomics sequencing technologies and Hi-C technology for genome assembly.The assembled genome has a total size of~1.17 Gb and 12 chromosomes,with a contig N50 of 5.26 Mb,consisting of 36,582 protein-coding genes.Repetitive sequences comprise 70.09%(811.14 Mb)of the eggplant genome,most of which are long terminal repeat(LTR)retrotransposons(65.80%),followed by long interspersed nuclear elements(LINEs,1.54%)and DNA transposons(0.85%).The S.melongena-HQ eggplant genome carries a total of 563 accession-specific gene families containing 1009 genes.In total,73 expanded gene families(892 genes)and 34 contraction gene families(114 genes)were functionally annotated.Comparative analysis of different eggplant genomes identified three types of variations,including singlenucleotide polymorphisms(SNPs),insertions/deletions(indels)and structural variants(SVs).Asymmetric SV accumulation was found in potential regulatory regions of protein-coding genes among the different eggplant genomes.Furthermore,we performed QTL-seq for eggplant fruit length using the S.melongena-HQ reference genome and detected a QTL interval of 71.29–78.26 Mb on chromosome E03.The gene Smechr0301963,which belongs to the SUN gene family,is predicted to be a key candidate gene for eggplant fruit length regulation.Moreover,we anchored a total of 210 linkage markers associated with 71 traits to the eggplant chromosomes and finally obtained 26 QTL hotspots.The eggplant HQ-1315 genome assembly can be accessed at http://eggplant-hq.cn.In conclusion,the eggplant genome presented herein provides a global view of genomic divergence at the whole-genome level and powerful tools for the identification of candidate genes for important traits in eggplant.

Endogenous Governance:Governance Way and Realization Path for Construction of Chinese Characteristic Town

As an important carrier of China's new urbanization,characteristic town can inject new vitality into local development,thus it is of great significance to urban-rural integration and rural revitalization.From the perspective of endogenous governance,it is able to fully understand the governance connotations of characteristic towns in the governance framework of image,instrument and action.Interest integration and sustainable development are the essential attributes that endogenous governance endows characteristic towns with vitality.The construction of characteristic towns follows a certain development logic.Roughly,it undergoes the development and transformation process of policy guidance,multiple governance,and endogenous governance.On the basis of this development logic,it is feasible to come up with a realization path for endogenous governance in characteristic towns in terms of functional elements,internal motivation and content innovation.

Assessing climate effects on wheat yield heterogeneity in the North China Plain and evolution from 1960 to 2020

This study quantified climate effects on wheat yield heterogeneity in the North China Plain from 1960 to 2020,by integrating the Agricultural Production Systems sIMulator,Optimal Parameters–based Geographical Detector model,and Ensemble Empirical Mode Decomposition model.The factors dominating yield heterogeneity varied by growth stage.For sowing to anthesis,anthesis to maturation,and the entire growth season,minimum temperature,radiation,and vapor pressure deficit has the greatest effect on yield heterogeneity.Interannual periodic oscillations govern the long–term evolution of climate effects on yield heterogeneity from 1960 to 2020.

Pan-genome of Raphanus highlights genetic variation and introgression among domesticated,wild,and weedy radishes

Post-polyploid diploidization associated with descending dysploidy and interspecific introgression drives plant genome evolution by unclear mechanisms.Raphanus is an economically and ecologically important Brassiceae genus and model system for studying post-polyploidization genome evolution and introgres-sion.Here,we report the de novo sequence assemblies for 11 genomes covering most of the typical sub-species and varieties of domesticated,wild and weedy radishes from East Asia,South Asia,Europe,and America.Divergence among the species,sub-species,and South/East Asian types coincided with Quaternary glaciations.A genus-level pan-genome was constructed with family-based,locus-based,and graph-based methods,and whole-genome comparisons revealed genetic variations ranging from single-nucleotide polymorphisms(SNPs)to inversions and translocations of whole ancestral karyotype(AK)blocks.Extensive gene flow occurred between wild,weedy,and domesticated radishes.High fre-quencies of genome reshuffling,biased retention,and large-fragment translocation have shaped the genomic diversity.Most variety-specific gene-rich blocks showed large structural variations.Extensive translocation and tandem duplication of dispensable genes were revealed in two large rearrangement-rich islands.Disease resistance genes mostly resided on specific and dispensable loci.Variations causing the loss of function of enzymes modulating gibberellin deactivation were identified and could play an important role in phenotype divergence and adaptive evolution.This study provides new insights into the genomic evolution underlying post-polyploid diploidization and lays the foundation for genetic improve-ment of radish crops,biological control of weeds,and protection of wild species'germplasms.

Impact of scientific and technological innovation policies on innovation efficiency of high-technology industrial parks-A dual analysis with linear regression and QCA

Scientific and technological innovation policies play a critical role in the innovative development of high-technology industrial parks.However,it remains unclear how scientific and technological innovation policies impact the innovation efficiency of hightechnology industrial parks and what the impact pathways are.An in-depth investigation of this topic can give an insight into the inherent relation between the scientific and technological innovation policies and technological innovation.By conducting a theoretical analysis,this study empirically analyzed the impact of scientific and technological innovation policies on the innovation efficiency of high-technology industrial parks.The main research methods applied in this study were linear regression and qualitative comparative analysis(QCA).The results showed that the policy targets drove innovation efficiency in a relatively minor way.Among all policy tools,the demand-based policy tools had the most significant influence on innovation efficiency.The supply-based and environment-based policy tools had notable positive impacts during the lag periods of policies.The policy mix pathways for scientific and technological innovation policies that impact innovation efficiency come in four forms,namely,the targets-directed,demand-driven,supplydominated environment optimization,and environment-dominated comprehensive pathways.Therefore,this study put forward proposals on classifying and refining the scientific and technological innovation policies and optimizing the policy mix-driven models.

Diet and Nutrition of Healthcare Workers in COVID-19 Epidemic—Hubei,China,2019

From late January to March,more than 42,000 doctors,nurses,public health workers,and health administrators across China went to Hubei Province to assist in the response to coronavirus disease 2019(COVID-19).There are many studies on nutrition status of affected people amid natural disasters or pandemics(1–3),but the diet and nutrition status of healthcare workers receive little attention.The aim of this article is to provide evidence for addressing this issue by investigating food supply and nutrition status during the COVID-19 response period.

Nanomedicine for tumor therapy-current status and challenges

The field of nanomedicine in controlled drug delivery systems, especially for tumor targeting, has tremendously progressed over the past decades because of its plentiful benefits, such as biocompatibility, stability in blood circulation, and ability to reduce side effects. Although a large number of relevant papers are published every year, few nanodrugs are available for clinical treatment. The present review aimed to explore the barriers in nanomedicine delivery and tumor targeting. Rational design of nanomedicine should consider not only tumor heterogeneity, in vivo metabolism, and physicochemical properties, but also more efficient innovations in particulate formulations for clinical application.

Health Status and Food Intake Frequency of Elderly Residents During COVID-19 Community Closure—Jiangxia District,Wuhan City,China,2020

What is already known about this topic?Elderly persons are vulnerable to infectious diseases,and nutritional status and health conditions were important to evaluate for disease prevention and ability to recover for the elderly during the coronavirus disease 2019(COVID-19)pandemic.What is added by this report?In our study,a rapid assessment questionnaire was used to investigate the change of household life and dietary intake of the elderly(aged 60 years or more)during community closure.Food consumption frequency of aquatic food products,soybeans,and fresh fruits declined dramatically with reductions of 70.9%,70.9%,and 53.0%,respectively,and 49.6%of the elderly lived with chronic non-communicable diseases but had little knowledge of nutrition and health.What are the implications for public health practice?Community closure measures in Wuhan City have played a key role in cutting off the transmission route of COVID-19 and protecting vulnerable groups.As a high-risk population,the elderly should be advised to maintain and strengthen a balanced diet with proper nutrition through increasing intake of aquatic food products,soybeans,fruits,and vegetables,reducing total caloric intake,and decreasing oil and salt consumption.These measures will be significant for the elderly to reduce the risk of chronic disease complications and COVID-19 infection and to decrease the chance of critical illness.