Intelligent reflecting surface for sum rate enhancement in MIMO systems

The research for the Intelligent Reflecting Surface(IRS)which has the advantages of cost and energy efficiency has been studied.Channel capacity can be effectively increased by appropriately setting the phase value of IRS elements according to the channel conditions.However,the problem of obtaining an appropriate phase value of IRs is difficult to solve due to the non-convex problem.This paper proposes an iterative algorithm for the alternating optimal solution in the Single User Multiple-Input-Multiple-Output(SU-MIMO)systems.The proposed iterative algorithm finds an alternating optimal solution that is the phase value of IRS one by one.The results show that the proposed method has better performance than that of the randomized IRS systems.The number of iterations for maximizing the performance of the proposed algorithm depends on the channel state between the IRS and the receiver.

Channel Estimation for Reconfigurable Intelligent Surface Aided Multiuser Millimeter-Wave/THz Systems

It is assumed that reconfigurable intelligent surface(RIS)is a key technology to enable the potential of mmWave communications.The passivity of the RIS makes channel estimation difficult because the channel can only be measured at the transceiver and not at the RIS.In this paper,we propose a novel separate channel estimator via exploiting the cascaded sparsity in the continuously valued angular domain of the cascaded channel for the RIS-enabled millimeter-wave/Tera-Hz systems,i.e.,the two-stage estimation method where the cascaded channel is separated into the base station(BS)-RIS and the RIS-user(UE)ones.Specifically,we first reveal the cascaded sparsity,i.e.,the sparsity exists in the hybrid angular domains of BS-RIS and the RIS-UEs separated channels,to construct the specific sparsity structure for RIS enabled multi-user systems.Then,we formulate the channel estimation problem using atomic norm minimization(ANM)to enhance the proposed sparsity structure in the continuous angular domains,where a low-complexity channel estimator via Alternating Direction Method of Multipliers(ADMM)is proposed.Simulation findings demonstrate that the proposed channel estimator outperforms the current state-of-the-arts in terms of performance.

不同EMS处理时间对大豆诱变后代主要品质含量变化影响分析

为探究不同EMS处理时间对大豆诱变后代主要品质含量变化的影响,文章利用0.5%EMS溶液处理大豆高蛋白品系公交1057-1,分别浸泡4、7和10 h(清水冲洗处理为对照),对播种后获得的连续4代诱变后代主要品质含量变化进行分析。结果表明,与对照相较,经EMS处理后的植株成活率随处理时间延长而降低。其中,经EMS-4处理后的植株成活率最高,为43.5%;经EMS-10处理后的植株成活率最低,仅为16.0%。不同EMS处理时间对大豆诱变后代的蛋白质含量影响显著,对脂肪含量影响不明显。其中经EMS-4处理的诱变后代蛋白质含量高于其他3组处理;经EMS-4处理后的M2代蛋白质含量发生显著分离,并出现超亲个体,脂肪含量变化不显著。

甲基磺酸乙酯(EMS)对谷子种子及幼苗活力的影响

为了探明甲基磺酸乙酯(EMS)诱变嫩选18种子构建突变体库的最适条件,加快品种选育进程,本研究对嫩选18种子进行了3种处理时间、3种EMS处理浓度的化学诱导,并对M1种子发芽及幼苗生长的诱变效应进行研究。结果表明:与对照相比,EMS处理在浓度0.4%下浸种6 h对嫩选18的发芽率及幼苗生长影响差异不显著,随着EMS浸种浓度、时间增加,种子萌发及幼苗生长逐渐受到抑制,在1.2%浓度下浸种14 h对种子萌发及幼苗生长抑制作用最强,极大降低了嫩选18的发芽势、发芽率、成苗率,并且导致幼苗生长缓慢。以存活率达到50%为标准,通过回归方程计算出在6 h、10 h、14 h浸种时间下,EMS浓度的半致死剂量分别为0.99%、0.72%、0.38%,可作为嫩选18 EMS诱变建立突变体库的适合条件。

混凝土坝面作业场景智能识别ResNet50-SEMSF方法

为提高混凝土坝面作业场景识别工作效率,提出了一种混凝土坝面作业场景智能识别方法(ResNet50-SEMSF)。将采集的坝面施工现场监控视频分割为图像,分析混凝土坝面作业人、机、料、环境等实体要素图像特征,界定坝面作业典型场景;以残差网络(ResNet50)为骨干网络结构,引入挤压激励(SE)注意力机制,关注不同通道间特征关系,提升坝面作业场景图像中多目标实体要素关键特征表达能力;融合下采样多尺度特征,保留坝面作业场景图像低级特征和高级语义信息,增强模型对图像不同层次特征的理解能力,克服尺度变化、目标变形等问题。对比分析其他3种卷积神经网络模型试验结果,使用梯度类激活映射(Grad-CAM)可视化方法,解释ResNet50-SEMSF模型对场景类别中实体要素信息的关注程度。结果表明:ResNet50-SEMSF识别效果明显优于ResNet50、MobileNetV2、VGG16等经典网络模型,表明ResNet50-SEMSF模型用于混凝土坝面作业场景智能识别的可行性,为混凝土坝面施工安全管理工作提供参考。

达乌里胡枝子愈伤组织及种子EMS诱变研究

为优化达乌里胡枝子愈伤诱导培养基的激素含量及比例,明确甲基磺酸乙酯(EMS)诱变愈伤组织及种子的最佳条件,本研究以达乌里胡枝子种子为外植体,探究了不同激素配比对愈伤诱导的影响,并针对愈伤组织和种子处理分别设置了两时间两浓度(2 h和6 h,0.3%和0.9%)及三时间两浓度(6 h、8 h、10 h,0.4%、0.8%)的EMS处理时间和浓度的组合,研究各处理对愈伤分化系数和后期植株成活率以及种子发芽率、发芽势和幼苗表型变异的影响。结果表明,达乌里胡枝子种子愈伤的最佳激素配比为0.25 mg/L NAA+0.5 mg/L 6-BA+0.5 mg/L 2,4-D,此时达乌里胡枝子愈伤诱导率为94.9%。EMS诱变达乌里胡枝子愈伤组织的适宜浓度为0.3%,处理时间为6 h,分化系数和植株相对成活率分别为46.31%和47.78%,接近半致死范围,且生根数、根长和平均株高等指标与高浓度EMS处理相比受到的负面影响较小。EMS诱变达乌里胡枝子种子的适宜浓度为0.8%,处理时间10 h,发芽率、出苗率、成苗率分别为53.61%、51.06%和53.28%,均接近半致死量,同时发现多株幼苗叶片出现了明显的形态变异。本试验在达乌里胡枝子原有种质资源基础上,丰富了达乌里胡枝子突变体库,也为后续开展达乌里胡枝子诱变育种研究提供理论依据。

禾本科植物EMS诱变研究进展

EMS是化学诱变中最常用的诱变剂,EMS诱变具有单个碱基点突变率高、成本低、易操作等优点,通过EMS诱变获得突变体可以为育种和基因功能研究提供有利的材料。EMS诱变技术的关键是确定EMS浓度和诱变时间,一般以达到半致死率的浓度和时间为最佳处理组合。禾本科植物中主要以种子为诱变材料,同时花粉、愈伤组织以及依靠营养繁殖的禾本科植物的营养器官也可以作为诱变材料。不同植物材料对EMS的耐受性不同,花粉最敏感,其次是愈伤组织,无性繁殖材料和种子的耐受性较强。突变体的筛选方式包括表型对比筛选、逆境定向筛选和正、反向遗传学筛选。本文综述了近年来EMS诱变技术在禾本科植物育种和基因功能研究中的应用,介绍了EMS的诱变原理、诱变剂浓度、处理时间、诱变处理材料的选择及突变体的筛选,并对未来禾本科植物中的EMS诱变研究进行了展望,为今后禾本科植物的EMS诱变研究提供参考。

EMS诱变对鹰嘴紫云英种子萌发及幼苗表型特征的影响

【目的】筛选适宜鹰嘴紫云英的EMS诱变条件。【方法】以鹰嘴紫云英品种甘绿2号种子为试验材料,采用不同浓度(0、0.2%、0.4%、0.6%、0.8%)的甲基磺酸乙酯(EMS)进行不同时间(2、4、6、8 h)的诱变处理,探究EMS对鹰嘴紫云英种子萌发特征及表型变化的影响。【结果】低浓度和短时间EMS处理促进鹰嘴紫云英种子的萌发,随EMS浓度升高和诱变时间的增加,对鹰嘴紫云英种子萌发产生抑制作用。种子浸出液电导率随诱变条件的加深呈上升趋势,在2~6 h时,萌发期发芽率、发芽势、幼苗苗长和根长均随处理时间和诱变浓度的增加呈先升高后降低的趋势,在8 h处理下,随EMS浓度的增加呈逐渐降低趋势,EMS浓度在0.8%时,种子发芽率和发芽势均达到最低,较对照分别降低了54.45%和56.67%;经形态学筛选,发现有鹰嘴紫云英幼苗表现出幼苗矮小、停滞生长、叶片黄化、宽叶、窄叶、叶片发紫、诸多病斑等特殊变异性状。【结论】0.8%EMS处理6 h可作为最佳诱变组合;幼苗的生长随诱变时间和浓度增加而明显受到抑制,且表型变异类型也逐步增多。

芒果^(60)Co-γ、EMS诱变及SC-SSR分子标记遗传多样性分析

诱变育种是短时间内增加物种遗传多样性和表型变异的最有效方法之一。为探明诱变创制芒果突变体基因库可行性,本研究以凯特芒果为试验材料,通过^(60)Co-γ射线辐射枝条和EMS溶液浸泡种子创制诱变群体材料,利用SC-SSR分子标记进行遗传多样性分析。结果表明:^(60)Co-γ射线辐射半致死剂量为31.37 Gy,0.2%EMS溶液浸泡半致死时间为5.9 h;利用16对SC-SSR引物分析100份诱变材料和1份凯特材料的遗传多样性,共检测出117个多态性位点,引物多态性条带百分比、多态性信息含量(PIC)、观测等位基因数(Na)、有效等位基因数(Ne)、Nei’s基因多样性指数(H)和Shannon’s信息指数(I)平均值分别为93.18%、0.610、1.923、1.583、0.334和0.493;试验材料间遗传相似系数在0.373~0.984之间,平均为0.779。诱变增加了芒果遗传信息,其中EMS诱变种子变异更大,本研究结果为芒果诱变育种提供了理论依据。

基于EMS管理模式的延续性护理在学龄前喘息性疾病儿童中的应用观察

目的·探讨基于EMS[环境管理(environment management,E)、用药指导(medicine direction,M)与自我监测(self monitoring,S)]管理模式的延续性护理在学龄前喘息性疾病儿童中的应用效果。方法·选取2019年12月至2020年11月,在上海交通大学医学院附属儿童医院呼吸科收治的67例0~6岁喘息性疾病患儿,按照随机数字表分为观察组33例和对照组34例,其中失访3例,最终每组32例。观察组采用基于EMS管理模式的延续性护理,对照组给予常规护理和出院电话随访。2组患儿出院后1、3、6个月随访评估儿童呼吸和哮喘测试(Test for Respiratory and Asthma Control in Kids,TRACK)结果、喘息复发情况;出院后6个月随访采用支气管哮喘用药依从性评分表(Medication Adherence Report Scale for Asthma,MARS-A)和护理工作满意度调查表评估用药依从性及护理工作满意度。结果·2组患儿人口学特征及临床基线特征差异无统计学意义。重复测量方差分析结果显示,时间、组别、组别×时间的交互作用对TRACK总分的影响均有统计学意义;出院后1、3、6个月,观察组TRACK总分均显著高于对照组(均P=0.000);2组患儿TRACK总分均随时间推移逐渐上升(P=0.000)。观察组1、3、6个月随访发现喘息复发率分别为25.0%、18.7%、9.4%,均显著低于对照组(分别为50.0%、43.7%、31.3%,均P<0.05);广义估计方程分析显示组间比较差异有统计学意义(P=0.013),观察组干预效果优于对照组(OR=0.292)。出院后6个月观察组MARS-A得分为(4.519±0.395)分,显著高于对照组[(3.994±0.739)分,P=0.001]。护理工作满意度调查结果显示,观察组显著高于对照组(P=0.000)。患儿MARS-A得分与护理工作满意度呈中度正相关(r=0.389,P=0.001)。结论·基于EMS管理模式的延续性护理可显著提高学龄前喘息性疾病儿童的用药依从性和喘息控制水平,明显降低喘息复发率,以及提高护理工作满意度。

籽用美洲南瓜EMS诱变突变体库的构建及表型分析

【目的】构建籽用美洲南瓜突变体库,加快籽用美洲南瓜种质资源创新进程,对南瓜品种选育、品种改良以及遗传基础的拓宽具有重要的意义。【方法】利用1.8%诱变剂甲基磺酸乙酯(EMS)处理籽用美洲南瓜ZHL4种子15 h,然后对M_(1)和M_(2)代群体单株进行表型变异观察,同时对M_(2)群体变异株系ZHL4-33进行显微组织结构观察。【结果】(1)M_(2)群体中共筛选到242个突变植株,45种表型变异,变异类型涵盖了突变株的各个生长时期以及各植物器官,总的突变频率达到25.17%。(2)突变体叶片栅栏组织厚度显著高于野生型,排列紧凑,维管形成层痕迹明显;突变体茎维管束多而密集,导管直径小于野生型,髓部发达,细胞间隙较小,细胞数目有所增加。【结论】初步构建了由425个M_(2)家系所组成的籽用美洲南瓜突变体库,为籽用美洲南瓜功能基因组研究和新品种选育奠定了材料基础。

EMS诱变对大麦种子萌发及M_(1)代植株成熟期主要性状的影响

为探究甲基磺酸乙酯(EMS)对大麦种子萌发及M_(1)代植株成熟期主要表型性状突变的影响,以啤酒大麦品种新啤6号为材料,分别用0.00%、0.05%、0.10%、0.15%和0.20%的EMS浸种10 h,分析各浓度EMS处理对种子发芽势、发芽率、致死率、畸变率、幼苗叶绿素含量、根系活力和形态指标的影响,记录0.10%EMS诱变后M_(1)代成熟期植株主要性状的突变类型和突变频率。结果表明,EMS明显抑制种子萌发和幼苗生长,并产生了大量的性状突变。与对照相比,0.10%EMS浸种显著降低了种子发芽势、发芽率、幼苗叶绿素含量和根系活力,致死率和畸变率显著提高;0.15%和0.20%EMS浸种显著降低了幼苗根和芽的长度、鲜重和干重,胚芽鞘干重显著提高。田间统计发现,0.10%EMS处理的M_(1)代植株主要突变性状集中在茎秆、叶片、穗形和育性等方面,产生了红秆、矮秆、红叶、芒卷、穗畸形、结实率低和分蘖少等性状,突变频率分别20.17%、4.87%、1.08%、16.67%、0.94%、14.00%和6.02%。因此,通过EMS诱变构建大麦突变体库和创制种质资源。

不同浓度EMS诱变不结球白菜的效果分析

为创制不结球白菜新种质,发掘新基因,探索不同浓度甲基磺酸乙酯(ethyl methane sulfonate,EMS)对不结球白菜的诱变效应。采用浓度为0.4%、0.6%和0.8%的EMS溶液对4个不结球白菜品种[黑塌菜(HTC)、香青菜(XQC)、JP241、XWZ]进行种子诱变处理,调查种子发芽情况与田间植株农艺性状表现。结果表明:4个不结球白菜品种的种子发芽势、发芽率和相对成苗率均随着EMS浓度的升高而逐渐降低,且处理间差异显著。EMS诱变可以引起不结球白菜叶色、叶形、株型、花器官等性状发生变异。不同品种不结球白菜的EMS诱变半致死剂量有所不同,产生的变异种类和变异频率也有所不同,HTC的半致死剂量为0.8%,相对变异频率为23.83%;XQC的半致死剂量为0.8%,相对变异频率为17.61%;JP241的半致死剂量为0.6%,相对变异频率为38.45%;XWZ的半致死剂量为0.6%,相对变异频率16.69%。EMS的浓度越高,诱变的不结球白菜始花开放时间越晚,莲座叶叶片数越少,雄性不育率越高。

EMS诱变的水稻不同位点突变体对ALS抑制剂类除草剂抗性差异

稻田杂草严重威胁水稻生长,培育抗除草剂水稻新品种,是高效解决稻田杂草危害的重要途径之一。本研究利用甲基磺酸乙酯(EMS)对华占水稻进行化学诱变,创建突变体,利用乙酰乳酸合成酶(ALS)抑制剂类除草剂甲咪唑烟酸(20 g/hm 2,有效成分)对突变体进行筛选,获得抗甲咪唑烟酸突变体材料,并对上述突变体的OsALS基因序列进行分析,明确其突变类型。最后对不同突变类型对甲氧咪草烟和甲基二磺隆的交互抗性进行分析。结果表明,华占水稻经EMS诱变和甲咪唑烟酸筛选后共获得11株抗甲咪唑烟酸突变体材料,其突变类型为Pro171Leu、Ser627Cys、Ser627Asn和Gly628Glu 4种。其中,Ser627Cys为首次发现的突变类型。4种突变类型对甲咪唑烟酸的抗性水平存在一定的差异,Ser627Asn、Ser627Cys、Pro171Leu、Gly628Glu突变类型的抗性指数分别为8.71、5.16、3.28和3.69。4种突变类型对甲氧咪草烟和甲基二磺隆的抗性亦存在显著差异。其中,Ser627Asn突变类型对甲氧咪草烟的抗性最高,抗性指数为20.57,Gly628Glu对甲基二磺隆抗性最高,抗性指数为5.11。综上,本研究通过EMS诱变获得了4种抗ALS抑制剂类除草剂的华占水稻突变类型,并鉴定了其对甲咪唑烟酸的抗性差异及对甲氧咪草烟和甲基二磺隆的交互抗性,为进一步的抗除草剂水稻品种培育和除草剂轮换使用提供依据。

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.

Triboelectric‘electrostatic tweezers'for manipulating droplets on lubricated slippery surfaces prepared by femtosecond laser processing

The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.

Recent progress in microbial cell surface display systems and their application on biosensors

Microbial cell surface display technology is a recombinant technology to express target proteins on the cell membrane,which can be used to redesign the cell surface with functional proteins and peptides.Bacterial and yeast surface display systems are the most common cell surface display systems of prokaryotic and eukaryotic proteins,that are widely applied as the core elements in the field of biosensors due to their advantages,including enhanced stability,high yield,good safety,expression of larger and more complex proteins.To further promote the performance of biosensors,the biomineralized microbial surface display technology was proposed.This review summarized the different microbial surface display systems and the biomineralized surface display systems,where the mechanisms of surface display and biomineralization were introduced.Then we described the recent progress of their applications on biosensors for different types of detection targets.Finally,the outlooks and tendencies were discussed and forecasted with the expectation to provide some general functions and enlightenments to this aspect of research.

EMS诱变菜豆子叶节定向筛选耐羟脯氨酸(HYP)突变体

以双丰一号菜豆子叶节为外植体,利用化学诱变剂EMS处理引发基因突变,进行突变体定向筛选抗逆突变细胞系。以0.17%EMS诱变处理2 h,子叶节的不再生率接近50%;以羟脯氨酸最大致死量3.5 mmol/L为筛选压力,定向筛选抗逆突变体。结果显示,在羟脯氨酸筛选培养基上,经EMS诱变的子叶节存活31个,突变率为8.61%,存活的子叶节再生率为74.19%,成功获得耐羟脯氨酸的突变株系。

上海某院EMS转运急性缺血性脑卒中患者院前延误的回顾性研究

目的 探究启动EMS(emergency medical service,紧急医疗服务)转运的急性缺血性脑卒中患者院前延误的影响因素,为急性缺血性脑卒中患者减少延误提高策略。方法 对132例启动EMS的急性缺血性脑卒中患者进行相关影响因素分析,包括年龄、性别、呼救时天气情况、脑卒中知识认知度,首发症状等,分为延误组(n=29)和及时组(n=103),通过多因素Logistics回归分析确定造成院前延误的影响因素。结果 两组患者在不同天气情况、卒中知识认知度、首发症状上存在差异(P<0.05)。多因素Logistics回归分析显示天气情况(OR=0.581,95%CI:0.358~0.943),卒中知识认知度(OR=0.238,95%CI:0.098~0.578)及首发症状为意识障碍(OR=0.076,95%CI:0.008~0.717)是减少院前延误的独立影响因素(P<0.05)。结论 较高卒中知识认知度、首发症状有意识障碍、天气情况良好有利于减少启动EMS转运的急性缺血性脑卒中患者的院前延误。因此,加强公众卒中知识普及培训,提高公众卒中意识,尽快启动EMS系统,可减少院前延误,改善患者预后。

Surface Metallization of Glass Fiber(GF)/Polyetheretherketone(PEEK) Composite with Cu Coatings Deposited by Magnetron Sputtering and Electroplating

Surface metallization of glass fiber(GF)/polyetheretherketone(PEEK)[GF/PEEK] is conducted by coating copper using electroplating and magnetron sputtering and the properties are determined by X-ray diffraction(XRD), scanning electron microscopy(SEM), and electron backscatter diffraction(EBSD).The coating bonding strength is assessed by pull-out tests and scribing in accordance with GB/T 9286-1998.The results show that the Cu coating with a thickness of 30 μm deposited on GF/PEEK by magnetron sputtering has lower roughness, finer grain size, higher crystallinity, as well as better macroscopic compressive stress,bonding strength, and electrical conductivity than the Cu coating deposited by electroplating.