Ultrasonographic Segmentation of Fetal Lung with Deep Learning

The morbidity and mortality of the fetus is related closely with the neonatal respiratory morbidity, which was caused by the immaturity of the fetal lung primarily. The amniocentesis has been used in clinics to evaluate the maturity of the fetal lung, which is invasive, expensive and time-consuming. Ultrasonography has been developed to examine the fetal lung quantitatively in the past decades as a non-invasive method. However, the contour of the fetal lung required by existing studies was delineated in manual. An automated segmentation approach could not only improve the objectiveness of those studies, but also offer a quantitative way to monitor the development of the fetal lung in terms of morphological parameters based on the segmentation. In view of this, we proposed a deep learning model for automated fetal lung segmentation and measurement. The model was constructed based on the U-Net. It was trained by 3500 data sets augmented from 250 ultrasound images with both the fetal lung and heart manually delineated, and then tested on 50 ultrasound data sets. With the proposed method, the fetal lung and cardiac area were automatically segmented with the accuracy, average IoU, sensitivity and precision being 0.98, 0.79, 0.881 and 0.886, respectively.

界面电子扰动促进的C–H键活化

丙烯是重要的化工原料,广泛用于生产聚丙烯、环氧丙烷、丙烯醛、丙烯腈和丙酮等重要化工中间体以及合成树脂、合成橡胶和许多精细化工产品.目前生产丙烯的方法主要有石脑油裂解、催化流化裂化、丙烷脱氢、烯烃复分解和甲醇制烯烃等.其中丙烷脱氢因具有较高的丙烯选择性和较低的原料成本而备受关注,尤其是页岩气在全球的大量发现和开采,使得丙烷的原料成本持续下降,丙烷脱氢技术的迅速发展,但高效催化剂研发成为提升生产效率的关键.商业Pt基催化剂通常采用合金化的手段优化Pt颗粒的表面结构和中间体的吸附状态,进而获得较好的催化性能,但金属助剂的引入在一定程度上会弱化Pt位点的C–H键活化能力.针对该问题,本文从惰性C–H键活化角度出发,揭示了一种新的C–H键界面活化机制.通过金属-载体强相互作用诱导形成Pt-Ga_(2)O_(3)反向界面结构,密度泛函理论计算结果表明,Pt与Ga_(2)O_(3)之间存在强烈的电子扰动现象,使得界面处O位点表现出类金属的电子特性,在费米能级附近存在连续的电子态,这与Ga_(2)O_(3)本身离散性电子态呈明显对比,显示出Pt-Ga_(2)O_(3)反向界面结构的独特性质,使得界面O位点表现出极强的H吸附能和C–H键活化能力,其催化丙烷分子中亚甲基C–H键断裂的活化能仅为0.21 eV,远低于Pt(111)晶面的0.64 eV.原位红外光谱结果表明,反应过程中该界面结构会产生大量的羟基.根据过渡态的精细结构可知,反应位点是通过抓取H原子并随即稳定产生的C自由基完成C–H键的断裂,分析结果表明,H吸附能与反应能垒有着紧密的关联,而Pt-Ga_(2)O_(3)反向界面结构中,Pt基底赋予界面O位点独特的电子结构,同时也可以作为电子受体接收H传递的电子,从而表现出极强的H结合能和C–H键活化能力,其C–H断裂能垒要远低于各类Pt位点.进一步的分析表明,首个C–H键在Pt–O界面位发生断裂后,所形成的H物种会由O位点溢流至Pt颗粒表面,最终以H_(2)形式释放,留下的2-丙基碎片再经历甲基的C–H键断裂、H溢流、脱氢等步骤形成丙烯分子.而Pt颗粒表面的Ga_(2)O_(3)团簇也起到分割表面位点的作用,促进丙烯脱附的同时,有效弱化C–C键的断裂趋势,减少裂解副产物,生成丙烯的选择性超过99%.综上所述,本文构建的Pt/Ga-Al_(2)O_(3)界面位催化剂在丙烷脱氢反应中的性能要明显优于Pt/Al_(2)O_(3)以及工业常用的PtSn/Al_(2)O_(3)催化剂,揭示了一种全新的C–H键活化策略,并探究其中的化学机制,既可以深化对界面协同催化的理解,又可以为高性能催化剂的设计提供借鉴和指导.

Status quo and factors of depression and anxiety in patients with non-muscle invasive bladder cancer after plasma electrocision

BACKGROUND Bladder cancer is a type of cancer with a high incidence in men.Plasma electrosurgery(PES)is often used in the treatment of bladder cancer.Postoperative complications often cause depression and anxiety in patients after surgery.AIM To investigate the current state of depression and anxiety after PES in patients with non-muscle-invasive bladder cancer and analyze the factors affecting them.METHODS A retrospective study was conducted to compare the baseline data of patients by collecting their medical history and grouping them according to their mental status into negative and normal groups.Logistic regression analysis was used to explore the risk factors affecting the occurrence of anxiety and depression after surgery in patients with bladder cancer.RESULTS Comparative analyses of baseline differences showed that the patients in the negative and normal groups differed in terms of their first surgery,economic status,educational level,and marital status.A logistic regression analysis showed that it affected the occurrence of anxiety in patients with bladder cancer,and the results showed that whether the risk factors were whether or not it was the first surgery,monthly income between 3000 and 3000-6000,secondary or junior high school education level,single,divorced,and widowed statuses.CONCLUSION The risk factors affecting the onset of anxiety and depression in bladder cancer patients after PES are the number of surgeries,economic status,level of education,and marital status.This study provides a reference for the clinical treatment and prognosis of bladder cancer patients in the future.

Immobilization of Laccase from Ganoderma lucidum LYL 263 in Sol-gel System

[Objective] The aim was to study the immobilization of laccase from Canoderma lucidum in three different sol-gel systems to find out the optimum ma- terials for laccase immobilization. [ Method ] Laccase from G. lucidum LYL 263 was immobilized in sodium alginate-gelatin, sodium alginate-chitosan and sodium alginate-gelatin-chitosan sol-gel systems, respectively; and the laccase activity was preliminarily analyzed. [ Result] The activity of laccase immobilized in sodium alginate-gelatin-chitosan was 2.14 folds and 2.75 folds respectively, compared to sodium alginate-gelatin and sodium alginate-chitosan; and this optimum system contained sodium alginate 2.0% , gelatin 1.0%, chitosan 0.3% and calcium chloride 56%. Benzoic acid was firstly used to embed immobilized laccase in this study, and single-factor experiments revealed that the activity of laccase could be effectively improved by suitable content of benzoic acid. The optimal conditions for laccase immobilization in the system were be^oie acid 2 retool/L, glutaraldehyde 0.32%, cross-linking reaction time 50 rain and enzyme concentration 10.0% ; and then the activity of the immobilized enzyme reached 635.7 U/g with these conditions. The thermal stability of the immobilized laccase was higher than free lac- case, and the activity of immobilized enzyme treated by freeze-drying was 1.59 folds compared to the non-freeze-dried, but the freeze-dried immobilized laccase had poor operational stability. [ Conclusion] The compositions of the material had significant influence on laccase immobilization and this study will provide reference to select materials for immobilization of laccase from G. lacidum LYL 263.

Impact of the Horizontal Heat Flux in the Mixed Layer on an Extreme Heat Event in North China:A Case Study

Extreme heat over the North China Plain is typically induced by anomalous descending flows associated with anticyclonic circulation anomalies. However, an extreme heat event that happened in the North China Plain region on 12–13 July 2015,with maximum temperature higher than 40℃ at some stations, was characterized by only a weak simultaneous appearance of an anomalous anticyclone and descending flow, suggesting that some other factor(s) may have induced this heat event. In this study, we used the forecast data produced by the Beijing Rapid Updated Cycling operational forecast system, which predicted the heat event well, to investigate the formation mechanism of this extreme heat event. We calculated the cumulative heat in the mixed-layer air column of North China to represent the change in surface air temperature. The cumulative heat was composed of sensible heat flux from the ground surface and the horizontal heat flux convergence. The results indicated that the horizontal heat flux in the mixed layer played a crucial role in the temporal and spatial distribution of high temperatures.The horizontal heat flux was found to be induced by distinct distributions of air temperatures and horizontal winds at low levels during the two days, implying a complexity of the low-level atmosphere in causing the extreme heat.

用于高精度催化性能预测的精细结构敏感型深度学习框架

催化剂表面的精细结构对结构敏感型反应有很大影响,高通量(HT)筛选和机器学习(ML)可以有效地探索这些影响因素.为了将ML与化学相结合,必须首先将化学结构转换为可用作ML模型输入的特征编码,目前常用的两种转换方法为描述符和图.然而,描述符的构建往往忽略原子连接,这使得ML模型难以捕获与催化性能最相关的几何信息.基于图的ML模型在更新节点的过程中会不可避免地丢失吸附位点的几何排列信息,同时消息传递神经网络复杂,导致其对电子或几何结构不敏感、缺乏可解释性.因此,目前仍然缺乏可以同时兼顾多相催化中电子和几何精细结构的可解释ML框架.相比之下,将化学结构转换为网格数据可以完全保留精细的几何信息.鉴于此,通过将催化剂表面结构和吸附位点信息分别转换为二维网格和一维描述符,本文创建了一个名为“整体+局部”卷积神经网络(GLCNN)的数据增强(DA)卷积神经网络(CNN)ML框架,其结合“整体+局部”特征,无需复杂的编码即可捕获原始精细结构,DA的加入可以扩充数据集并减缓过拟合.GLCNN可以很好地预测和区分碳基过渡金属单原子催化剂上OH的吸附能,平均绝对误差小于0.1 eV,这是在大型数据集上训练的ML模型所能达到的较好结果.将GLCNN与基于描述符或图的模型对比,结果表明,对比模型无法完全准确预测包含IB和IIB过渡金属或者顺式/反式构型催化剂的OH吸附能.而GLCNN模型的预测效果明显好于对比模型,表明网格和描述符的组合可以更好地体现催化活性中心的电子和精细几何结构信息.另外,对DA处理后的样本计算平均标准误差后发现,通过DA获得的不同晶胞几乎不影响预测结果,说明DA对晶胞的平移并不改变晶胞的性质,表明GLCNN可以学习到周期性表面的边界条件信息.与传统的CNN和基于描述符的单边特征提取不同,本文中对精细结构敏感的ML框架可以通过不包含人类偏见的可解释性分析,从几何和化学/电子特征中提取影响催化性能的关键因素,如对称和配位元素.一维描述符的特征重要性分析表明,吸附位点的电子结构和对称性特征至关重要,且金属对于催化性能的影响强于其配位环境.将CNN卷积部分的中间输出可视化后发现,碳基载体上远离金属的区域中很大一部分对催化性能几乎没有直接影响,且卷积层会优先对金属原子反复关注,再次强调金属的重要性高于其配位环境,表明卷积核可以自动提取符合催化常识化学结构的几何信息.对全连接层(FC)进行降维可视化分析后发现,随着层数的增加,FC基于基本催化知识逐渐寻找特征提取的方向,提取出更抽象的有利于吸附能预测的高维特征,这与卷积部分类似.综上,GLCNN框架为具有广阔物理和化学空间的多相催化剂的高精度HT筛选提供了可行方案.

Tuning magneto-dielectric properties of Co_(2)Z ferrites via Gd doping for high-frequency applications

Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,and 0.20)materials are successfully prepared by using solid-state method at 925℃for 4 h with 2.5-wt%Bi_(2)O_(3)sintering aids.The content of Gd^(3+)ion can affect micromorphology,grain size,bulk density,and magneto-dielectric properties of the ferrite.With Gd^(3+)ion content increasing,saturation magnetization(Ms)first increases and then decreases.The maximum value of Ms is 44.86 emu/g at x=0.15.Additionally,sites occupied by Gd^(3+)ions can change magnetic anisotropy constant of the ferrite.Magnetocrystalline anisotropy constant(K_1)is derived from initial magnetization curve,and found to be related to spin-orbit coupling and intersublattice interactions between metal ions.The real part of magnetic permeability(μ′)and real part of dielectric permittivity(ε′)are measured in a frequency range of 10 MHz-1 GHz.When x=0.15,material has excellent magneto-dielectric properties(μ′≈12.2 andε′≈17.61),low magnetic loss(tanδμ≈0.03 at 500 MHz),and dielectric loss(tanδε≈0.04 at 500 MHz).The results show that Gd-doped Co_(2)Z ferrite has broad application prospects in multilayer filters and high-frequency antennas.

全球价值链网络中的“三足鼎立”格局分析

本文基于全球贸易、生产及消费数据测算分析了全球价值链从2000年到2017年的结构演变,我们发现,2000年全球贸易、生产及消费都呈现出以美国为核心的亚太区块和以德国为核心的欧洲区块的“双极结构”。而到2017年,以美国为核心的亚太区块分裂成以美国为核心的北美区块和以中国为核心的亚洲区块。当前全球价值链网络已呈现出“北美-欧洲-亚洲”的三足鼎立区块格局,美国、德国及中国作为其中的核心节点存在。在此背景下,各区块内、区块间如何实现协作共赢、中国如何发挥对亚洲经济的支撑作用,均是当前值得思考的重要问题。

A Deep Learning Method for Bias Correction of ECMWF 24–240 h Forecasts

Correcting the forecast bias of numerical weather prediction models is important for severe weather warnings.The refined grid forecast requires direct correction on gridded forecast products,as opposed to correcting forecast data only at individual weather stations.In this study,a deep learning method called CU-net is proposed to correct the gridded forecasts of four weather variables from the European Centre for Medium-Range Weather Forecast Integrated Forecasting System global model(ECMWF-IFS): 2-m temperature,2-m relative humidity,10-m wind speed,and 10-m wind direction,with a forecast lead time of 24 h to 240 h in North China.First,the forecast correction problem is transformed into an image-toimage translation problem in deep learning under the CU-net architecture,which is based on convolutional neural networks.Second,the ECMWF-IFS forecasts and ECMWF reanalysis data(ERA5) from 2005 to 2018 are used as training,validation,and testing datasets.The predictors and labels(ground truth) of the model are created using the ECMWF-IFS and ERA5,respectively.Finally,the correction performance of CU-net is compared with a conventional method,anomaly numerical correction with observations(ANO).Results show that forecasts from CU-net have lower root mean square error,bias,mean absolute error,and higher correlation coefficient than those from ANO for all forecast lead times from 24 h to 240 h.CU-net improves upon the ECMWF-IFS forecast for all four weather variables in terms of the above evaluation metrics,whereas ANO improves upon ECMWF-IFS performance only for 2-m temperature and relative humidity.For the correction of the 10-m wind direction forecast,which is often difficult to achieve,CU-net also improves the correction performance.

Protective Effect of Irbesartan by Inhibiting ANGPTL2 Expression in Diabetic Kidney Disease

Angiopoietin-like protein 2(ANGPTL2)stimulates inflammation and is important in the pathogenesis of diabetic kidney disease(DKD).Irbesartan is helpful in reducing diabetes-induced renal damage.In this study,the effects of irbesartan on DKD and its renal protective role involving ANGPTL2 in DKD rats were examined.Wistar rats were divided into normal,DKD,and DKD+irbesartan groups.The DKD+irbesartan group was treated once daily for 8 weeks with 50 mg/kg irbesartan via intragastric gavage.The 24-h urinary albumin was determined each week,renal pathological changes were observed,and expression of ANGPTL2 and nuclear factor-kappa B(NF-κB)in rat renal tissue was assessed by immunohistochemistry.Mouse podocytes cultured in a high concentration of glucose were classified into four groups based on the irbesartan concentrations(0,25,50,and 75ºg/mL).Expression of ANGPTL2 and phosphorylated IκB-αwas assessed by Western blotting.The mRNA levels of ANGPTL2 and monocyte chemotactic protein 1(MCP-1)were assessed by real-time polymerase chain reaction.The DKD rats displayed proteinuria,podocyte injury,and increased ANGPTL2 and NF-κB expression.All were relieved by irbesartan treatment.In podocytes cultured in elevated glucose,ANGPTL2 and phosphorylated IκB-αwere overexpressed at the protein level,and ANGPTL2 and MCP-1 were highly expressed at the mRNA level.Irbesartan down-regulated ANGPTL2 and phosphorylated IκB-αexpression at the protein level and inhibited ANGPTL2 and MCP-1 expression at the mRNA level.The ameliorative effects of irbesartan against DKD involves podocyte protection and suppression of ANGPTL2.

Enhancement of magnetic and dielectric properties of low temperature sintered NiCuZn ferrite by Bi_(2)O_(3)-CuO additives

With a series of 1.0 wt%Bi_(2)O_(3)-x wt%CuO(x=0.0,0.2,0.4,0.6,and 0.8)serving as sintering additives,Ni_(0.23)Cu_(0.32)Zn_(0.45)Ee_(2)O_(4)ferrites are successfully synthesized at a low temperature(900℃)by using the solid state reaction method.The effects of the additives on the phase formation,magnetic and dielectric properties as well as the structural and gyromagnetic properties are investigated.The x-ray diffraction(XRD)results indicate that the added Bi_(2)O_(3)-CuO can lower the synthesis temperature significantly without the appearing of the second phase.The scanning electron microscope(SEM)images confirm that Bi_(2)O_(3)is an important factor that determines the sintering behaviors,while CuO affects the grain size and densification.With CuO content x=0.4 or 0.6,the sample shows high saturation magnetization,low coercivity,high real part of magnetic permeability,dielectric permittivity,and small ferromagnetic resonance linewidth(ΔH).The NiCuZn ferrites are a promising new generation of high-performance microwave devices,such as phase shifters and isolators.

Genetic characteristics of a patient with multiple primary cancers:A case report

BACKGROUND Two or multiple primary malignant neoplasms(MPMNs)rarely occur in the same patient.It has been reported that MPMNs are easily misdiagnosed as the recurrence or metastasis of malignancies in clinical practice,affecting the choice of treatment for the patients,thereby resulting in the delay of optimal diagnosis.Next generation sequencing(NGS)can be used to distinguish between multiple primary lung cancers and intrapulmonary metastasis,and may distinguish the origin of tumours in different sites of the body.CASE SUMMARY We report the case of 66-year-old woman who suffered from different malignant neoplasms in the rectum and esophageal and gastrointestinal tract.The first neoplasm rectal adenocarcinoma was diagnosed and removed in 2016.The second and third lesions were diagnosed with esophageal squamous-cell carcinoma(ESCC)and gastrointestinal stromal tumour(GIST),respectively,in 2019.Nextgeneration whole exome sequencing was performed on the tissue specimens of rectal carcinoma,esophageal cancer,GIST,and white blood cells to investigate the relationship between malignancies at different timeframe and determine whether the ESCC and GIST evolved from the rectal adenocarcinoma.Mutations including v-Ki-ras2-Kirsten rat sarcoma viral oncogene homolog,adenomatosis polyposis coli,and mothers against decapentaplegic homolog 4 were detected in rectal adenocarcinoma sample,mast/stem cell growth factor receptor was detected in GIST tissue,and lysine methyltransferase 2D was detected in ESCC specimen.Overall,ESCC and GIST were not genetically evolved from rectal adenocarcinoma,and this patient did not have a trunk driven clone.CONCLUSION NGS is an effective tool to study clonal evolution of tumours and distinguish between MPMNs and intrapulmonary metastasis.

KIAA1199 induces advanced biological behavior and development of ovarian cancer through activation of the IL-6/STAT3 pathway

Recently,abnormal expression of KIAA1199 has been detected in Epithelial Ovarian Cancer(EOC).However,the underlined anti-ovarian cancer mechanism of KIAA1199 remains to be enlightened.In our study,we performed to elucidate the effects of KIAA1199 on the advanced biological behavior of EOC cells through activation of the IL-6/STAT3 pathway.Confirmed by immunohistochemistry,KIAA1199 was highly expressed in ovarian borderline and malignant epithelial tumors.A retrospective analysis found that EOC patients with low expression of KIAA1199 had a significantly higher 5-year survival rate than those with high expression.Mechanistically,IL-6 was used to stimulate EOC cells,and the expression of KIAA1199,STAT3 and p-STAT3 increased after IL-6 stimulation.These results could show that KIAA1199 is transcriptionally activated by IL6/STAT3 pathway,thereby accelerating the deterioration of EOC.KIAA1199 could also be used as a poor prognosis factor and potential target in treatment.

Prediction of the short-term efficacy of anti-VEGF therapy for neovascular age-related macular degeneration using optical coherence tomography angiography

Background To evaluate whether the specific choroidal neovascularization(CNV)characteristics measured using optical coherence tomography angiography(OCTA)can predict the 6-month prognosis of neovascular age-related macular degeneration(nAMD)after anti-vascular endothelial growth factor(anti-VEGF)therapy.Methods Patients with type 1,type 2,or mixed-type neovascularization(NV)were prospectively included.Participants underwent an initial loading phase of three consecutive monthly intravitreal injections of Conbercept(0.5 mg)and were switched to a pro re nata(PRN)treatment strategy.OCTA images were evaluated for eyes that underwent follow-up assessments for more than 6 months.CNV lesions were manually segmented,and the CNV area,vessel area,greatest vascular caliber(GVC),and greatest linear dimension(GLD)were compared between responders and non-responders.Two masked graders independently measured the above-mentioned parameters using OCTA,and consistency was assessed using the intraclass correlation coefficient(ICC)values.Multiple logistic regression analysis was performed to evaluate the effect of a 3-month change in the CNV area,GLD,and GVC on the 6-month response to anti-VEGF agents.Results Among the 60 eyes of 60 patients with nAMD,39 were responders and 21 were non-responders.The proportion of CNV types was significantly different between responders and non-responders(P=0.009).Patients with type 2 or mixed NV seemed more likely to respond to the treatment(28.2%vs.0.0%,and 30.8%vs.23.8%,respectively).The change in GVC showed a significant difference between responders(−4.98±17.17μm)and non-responders(11.01±14.10μm)after three monthly intravitreal anti-VEGF injections.Multiple logistic regression analysis showed that only the change in GVC remained significant after controlling for baseline GVC,injection number,and CNV type(adjusted OR=1.083;P=0.008).Conclusions Type 2 and mixed-type NV were significantly associated with a better response to anti-VEGF therapy.Changes in GVC after 3 months of treatment were significantly associated with a response to anti-VEGF therapy at 6 months.

Drug-eluting intraocular lens with sustained bromfenac release for conquering posterior capsular opacification

Cataract is the leading cause of visual impairment,and posterior capsular opacification(PCO)is the most common long-term complication of modern cataract surgery,which can cause severe visual impairment after surgery.The proliferation,migration,and epithelial-mesenchymal transition(EMT)of residual lens epithelial cells(LECs)stimulated by growth factors and cytokines,are the key pathological mechanisms involved in the development of PCO.This study demonstrated that non-steroidal anti-inflammatory drug(NSAID),bromfenac,was capable of effectively inhibiting cell migration,overexpression of EMT markers,such as fibronectin(FN),matrix metalloproteinase 2(MMP2),α-smooth muscle actin(α-SMA),and transcription factor Snail,and extracellular signal-regulated kinase(ERK)/glycogen synthase kinase-3β(GSK-3β)signaling induced by transforming growth factor-β2(TGF-β2)in vitro.The inhibitory effect of bromfenac on TGF-β2-induced EMT was also verified on a primary lens epithelial cell model using human anterior capsules.Furthermore,based on ultrasonic spray technology,we developed a drug-eluting intraocular lens(IOL)using poly(lactic-co-glycolic acid)(PLGA)with sustained bromfenac release ability for the prevention of PCO development.In the rabbit models of cataract surgery,bromfenac-eluting IOL exhibited remarkable PCO prevention and inflammation suppression effects with excellent biocompatibility.In conclusion,bromfenac can inhibit TGF-β2-induced cell migration and the EMT of LECs via ERK/GSK-3β/Snail signaling.The present study offers a novel approach for preventing PCO through PLGA-based drug sustained-release IOLs.

Influence of Near Real-Time Green Vegetation Fraction Data on Numerical Weather Prediction by WRF over North China

The green vegetation fraction(GVF)can greatly influence the partitioning of surface sensible and latent heat fluxes in numerical weather prediction(NWP)models.However,the multiyear averaged monthly GVF climatology—the most commonly used representation of the vegetation state in models—cannot capture the real-time vegetation state well.In this study,a near real-time(NRT)GVF dataset generated from an 8-day composite of the normalized difference vegetation index is compared with the 10-yr averaged monthly GVF provided by the WRF model.The annual variability of the GVF over North China is examined in detail.Many differences between the two GVF datasets are found over dryland,grassland,and cropland/grassland mosaic areas.Two experiments using different GVF datasets are performed to assess the impacts of GVF on forecasts of screen-level temperature and humidity.The results show that using NRT GVF can lead to a widespread reduction of 2-m temperature forecast errors from April to October.Evaluation against in-situ observations shows that the positive impact on 2-m temperature forecasts in the morning is more distinct than that in the afternoon.Our study demonstrates that NRT GVF can provide a more realistic representation of the vegetation state,which in turn helps to improve short-range forecasts in arid and semiarid regions of North China.Moreover,our study shows that the negative effect of using NRT GVF is closely related to the initial soil moisture.

Water-soluble pillar[4]arene[1]quinone: Synthesis, host-guest property and application in the fluorescence turn-on sensing of ethylenediamine in aqueous solution, organic solvent and air

Water-soluble pillar[5]arenes are a class of typical macrocycles and have aroused tremendous attention for its easy to modify, abundant host-guest properties and extensive applications. However, up to now, all the reported water-soluble pillar[5]arenes acted as the host molecules, whereas they failed to be postsynthetically modified, which seriously impeded the development of the pillar[5]arene-based supramolecular chemistry. In this work, a new water-soluble pillar[5]arene, pillar[4]arene[1]quinone, was designed and synthsized with eight quaternary ammonium groups as well as a quinone units. Such a new water-soluble pillar[4]arene[1]quinone was capable of forming 1:1 stable complex with sodium 1-octanesulfonate in aqueous solution. Since the 1,4-quinone unit of WP[4]Q[1] could react with ethylenediamine (EDA) to form a conjugated quinoxaline structure, so pillar[4]arene[1]quinone could apply to the facile fluorescence turn-on sensing of EDA in aqueous solution, organic solvent and air.

Strength and ductility enhancement of twin-roll cast Al-Zn-Mg-Cu alloys with high solidification intervals through a synergistic segregation-controlling strategy

Center segregation and banded intergranular segregation(B-IGS)should be well controlled to improve the mechanical properties of twin-roll cast(TRC)aluminum alloys,especially for alloys with high solid-ification intervals.In the present work,a synergistic grain refinement strategy was designed using an Al-5Ti-B grain refiner and Ti,Zr,and Sc microalloying elements to simultaneously control center seg-regation and B-IGS in TRC Al-Zn-Mg-Cu alloys.As the grain size decreased,center segregation defects were eliminated and transformed into dispersed B-IGS defects;simultaneously,the width and length of the B-IGS were also reduced.Moreover,the macro-distributions of the alloying elements along the thickness direction became more homogeneous due to a weak shear-induced dilation effect.The well-controlled multiscale segregation improved the uniformity of the alloy macrostructure,accelerated the redissolution of the crystalline phase,dispersed the aggregated residual phase,and refined grains under the T6 state.Hence,the strength and ductility of the alloys under the T6 state were simultaneously improved,and the hardness distribution along the thickness direction became more homogenous.Furthermore,the underlying mechanisms of segregation evolution and strength and ductility enhancements were elucidated.This work provides a novel strategy to effectively control multiscale segregation and produce high-performance aluminum alloys with high solidification intervals by TRC.

Pillar[6]arenes: From preparation, host-guest property to self-assembly and applications

Pillar[n]arenes primarily comprise pillar[5]arenes and pillar[6]arenes, which belong to the new class of supramolecular macrocyclic hosts. Pillar[n]arenes have aroused wide attention because of their highly rigid and symmetrical architectures, controllable cavity size, and wide applications in a wide variety of areas. Although pillar[6]arene is difficult to synthesize, numerous studies have been conducted on it. In this review, the strategies to synthesize and functionalize pillar[6]arenes are investigated systematically.In addition, their host-guest properties in organic solvents and in aqueous solution are described. Moreover, pillar[6]arenes applied in different fields(e.g., molecular recognition, drug release, cancer therapy,and gas separation) are clarified. Hopefully, this study is capable of arousing more attention from increasing scientists to study large-cavity pillar[n]arenes.

All-in-one functional supramolecular nanoparticles based on pillar[5]arene for controlled generation,storage and release of singlet oxygen

The storage and controlled release of singlet oxygen(^(1)O_(2))have attracted increasing attention due to the wide application and microsecond lifetime of^(1)O_(2)in water.Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative,a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin(TPP),that may provide the controlled generation,storage and release of singlet oxygen.We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene.The formed nanocarriers can be used to load TPP through their supramolecular self-assembly.The resulting nanoparticles show good water-solubility and uniform spherical morphology.After laser irradiation(660 nm),the nanoparticles exhibit excellent ability for the generation and storage of^(1)O_(2).When the irradiated nanoparticles are heated above 80°C,^(1)O_(2)can be released from the system.Therefore,in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system,which provides a new strategy for the controlled generation,storage and release of singlet oxygen.We believe this groundbreaking strategy will have a great potential in providing necessary amounts of^(1)O_(2)for the photodynamic therapy of tumors in dark.