Spatial distribution characteristics of bacterial community structure and gene abundance in sediments of the Bohai Sea

This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.

Q690高强钢在单调荷载下的延性断裂判据研究

Q690高强钢由于其优越的强度和自重比在工程结构中受到越来越多的关注。螺栓连接是钢结构节点组成的重要形式,了解Q690钢的延性断裂行为对于研究Q690构件之间螺栓连接的破坏形式至关重要。为了解决这一问题,使用传统的延性断裂分析方法对Q690钢进行了全面的初步研究,包括校准空穴扩张模型(VGM)和应力修正临界应变(SMCS)模型。对标准拉伸试件和不同缺口半径的圆棒缺口试件进行单调拉伸试验,通过对试验数据的分析得到了Q690钢的真实应力-应变关系和在不同应力三轴度下的工程应力-应变曲线。随后对断口进行电镜扫描试验,区分了试验试件的破坏模式,并对断口表面韧窝形成的凸起和凹陷进行分析,计算出Q690钢的特征长度,用于确定后续有限元模型的网格尺寸。建立有限元模型对试验加载过程进行模拟,使用校准后的本构模型计算出的工程应力-应变曲线与试验结果吻合较好。通过提取不同试件延性断裂发生时断裂起始点的应力应变状态确定了空穴扩张模型(VGM)和应力修正临界应变(SMCS)模型的断裂参数,并用其对试验试件的断裂位移进行预测。结果表明,传统的VGM和SMCS模型不能准确预测Q690试件的断裂,预测误差达到了31%和39%。在此基础上,提出了一种改进的孔洞生长模型,充分考虑了应力三轴度对断裂时临界塑性应变的影响。数值分析表明,改进后的断裂模型对试验试件的断裂位移的预测值与实测值吻合较好,平均误差控制在5%以内。研究强调了了解Q690高强钢延性断裂行为的重要性,并提出了一种改进的延性断裂模型,以提高预测其延性断裂的准确性。

Expansion and improvement of ChinaMu by MuT-seq and chromosome-level assembly of the Mu-starter genome

ChinaMu is the largest sequence-indexed Mutator(Mu)transposon insertional library in maize(Zea mays).In this study,we made significant improvements to the size and quality of the ChinaMu library.We developed a new Mu-tag isolation method Mu-Tn5-seq(MuT-seq).Compared to the previous method used by ChinaMu,MuT-seq recovered 1/3 more germinal insertions,while requiring only about 1/14 of the sequencing volume and 1/5 of the experimental time.Using MuT-seq,we identified 113,879 germinal insertions from 3,168 Mu-active F1 families.We also assembled a high-quality genome for the Mu-active line Mu-starter,which harbors the initial active MuDR element and was used as the pollen donor for the mutation population.Using the Mu-starter genome,we recovered 33,662(15.6%)additional germinal insertions in 3,244(7.4%)genes in the Mu-starter line.The Mu-starter genome also improved the assignment of 117,689(54.5%)germinal insertions.The newly upgraded ChinaMu dataset currently contains 215,889 high-quality germinal insertions.These insertions cover 32,224 pan-genes in the Mu-starter and B73Ref5 genomes,including 23,006(80.4%)core genes shared by the two genomes.As a test model,we investigated Mu insertions in the pentatricopeptide repeat(PPR)superfamily,discovering insertions for 92%(449/487)of PPR genes in ChinaMu,demonstrating the usefulness of ChinaMu as a functional genomics resource for maize.

Reliable sensors based on graphene textile with negative resistance variation in three dimensions

The weft-knitted reduced graphene oxide(r-GO)textile that is made up of many conductive r-GO coated fibers was successfully prepared dependent on the electrospray deposition technique.Interestingly,the r-GO textile presents negative resistance variation not only in axial direction as the pressure increases but also in transverse direction as the lateral stretch increases which makes it has the advantage to fabricate the reliable sensors based on strain-resistance effect.The transverse-strain and pressure sensors based on the r-GO textiles all show the excellent sensing characteristics such as high sensitivity,reliability,and good durability,etc.The maximum gauge factors(GF)of the transverse-sensor are 27.1 and 153.5 in the x-and/-direction,respectively.And the practical detection range can up to 40%in the x-direction and 35%in the y-direction,respectively.The r-GO textile pressure sensor also shows high sensitivity for a broad pressure range that with a GF up to 716.8 kPa-1 for less than 4.5 kPa region and still has more sensitive pressure sensing characteristics even the pressure goes up to 14 kPa.Based on those good performances of r-GO textile sensors,its potential applications in human body states monitoring have been studied.

Effect of high temperature cooking on the quality of rice porridge

In order to explore the effect of high-temperature cooking instant porridge on the taste and quality of porridge,this study explored the changes in the taste quality of rice porridge under different heating times(15 min,20 min,25 min and 30 min)at a higher initial temperature(100°C),and compared with that cooked at room temperature(25°C),and explained the reasons for the change.From the perspective of migration rate in moisture content,the rice porridge with special treatment has a more rapid moisture change,which makes texture,whiteness,smell and other factors change in a shorter time and increases the taste quality.It was concluded that under special treatment condition of starting with 100°C water and heating for 15 min,the kinds of rice flavor increased 2.2 times,the white of rice decreased by 10.04%,hardness decreased by 3.54 times,and the elasticity decreased by 35.48%respectively.In general,cooking with higher initial temperature(100°C)is more valuable than cooking from 25°C,in terms of the texture,flavor,saving time,and stable quality during the household and industrial production of instant porridge.

Phosphorus-doped iron-nitrogen-carbon catalyst with pentacoordinated single atom sites for efficient oxygen reduction

Single-atomic Fe-N4 is the well-acknowledged active site in iron-nitrogen-carbon(Fe-N-C)material for oxygen reduction reaction(ORR).The adjusting of the electronic distribution of Fe-N4 is promising for further enhancing the performance of the Fe-N-C catalyst.Herein,a phosphorus(P)-doped Fe-N-C catalyst with penta-coordinated single atom sites(FeNPC)is reported for efficient oxygen reduction.Fe K-edge X-ray absorption spectroscopy(XAS)verifies the coordination environment of single Fe atom,while density functional theory(DFT)calculations reveal that the penta-coordination and neighboring doped P atoms can simultaneously change the electronic distribution of Fe-N_(4)and its adsorption strength of key intermediates,reducing the reactionfree energy of the potential-limiting step.Electrochemical tests validate the remarkable intrinsic ORR activity of FeNPC in alkaline media(a half-wave potential(E_(1/2))of 0.904 V vs.reversible hydrogen electrode(RHE)and limited current density(JL)of 6.23 mA·cm^(−2))and an enhanced ORR performance in neutral(E_(1/2)=0.751 V,J_(L)=5.27 mA·cm^(−2))and acidic media(E_(1/2)=0.735 V,JL=5.82 mA·cm^(−2))with excellent stability,highlighting the benefits of optimizing the local environment of singleatomic Fe-N4.

Furan Donor for NIR-II Molecular Fluorophores with Enhanced Bioimaging Performance

The second near-infrared(NIR-II,1,000 to 1,700 nm)molecular fluorophores containing donor–acceptor–donor conjugated backbone have attracted substantial attention due to their outstanding advantages,such as stable emission and facilely tuned photophysical properties.However,it is still challenging for them to simultaneously achieve high brightness and red-shifted absorption and emission.Herein,furan is adopted as the D unit to construct NIR-II fluorophores,demonstrating red shift of absorption,enhanced absorption coefficient,and fluorescent quantum yield when compared with the generally used thiophene counterparts.The high brightness and desirable pharmacokinetics of the optimized fluorophore,IR-FFCHP,endows improved performance for angiography and tumor-targeting imaging.Furthermore,dual-NIR-II imaging of tumor and sentinel lymph nodes(LNs)has been achieved with IR-FFCHP and PbS/CdS quantum dots,enabling the in vivo imaging navigated LN surgery in tumor-bearing mice.This work demonstrates the potential of furan for constructing bright NIR-II fluorophores for biological imaging.

Characteristics of flax oil and milk mixture

In order to develop milk products both with better taste and more health benefits,a blended system of dairy products and flax oil was studied based on the Budwig diet.The amounts of flax oil added to the pure milk or yogurt were varied and the system was fully mixed without adversely affecting the flavor.The effects of flax oil addition on the frictional and rheological properties of different dairy products were investigated,and the optimal addition ratio was determined combined with the sensory evaluation.The experimental results showed that the addition ratio of flax oil significantly affected the friction characteristics and rheological properties of dairy products,in which the friction coefficient of the mixture tended to decrease as the addition of flax oil increased,and with the added increase the viscosities of both ordinary yogurt mixture and pure milk mixture tended to increase.Furthermore,based on physical characteristics and sensory properties the optimal addition ratios of flax oil to pure milk,ordinary yogurt,and non-fat yogurt are obtained,which are 2.5wt%,2.5wt%,and 5wt%,respectively.The study provides a quantified analysis way for the additions to the dairy products and the obtained data can be used for reference in production.