The Potassium Transporter AtKUP12 Enhances Tolerance to Salt Stress through the Maintenance of the K^(+)/Na^(+)Ratio in Arabidopsis

Potassium(K^(+))is a necessary nutrient for plant growth and crop production.The K^(+)transporter plays crucial roles in the absorption and transport of K^(+)in plants.Most K^(+)transporters in Arabidopsis have been reported,but AtKUP12,which is a member of the KT/KUP/HAK family,has not yet been the subject of relevant in-depth research.In the present study,we demonstrated that AtKUP12 plays a crucial role in K^(+)uptake in Arabidopsis under 100μM low-K^(+)and 125 mM salt stress conditions.AtKUP12 transcripts were induced by K^(+)deficiency and salt stress.We analyzed the K^(+)uptake of AtKUP12 using the K^(+)uptake-deficient yeast R5421 and Arabidopsis mutant atkup12.Transformation with AtKUP12 rescued the growth defect of mutant yeast and atkup12 mutant plants at the low-K^(+)concentration,which suggested that AtKUP12 might be involved in high-affinity K^(+)uptake in low-K^(+)environments.In comparison to the wild-type(WT)and atkup12-AtKUP12 complementation lines,atkup12 showed a dramatic reduction in potassium concentration,K^(+)/Na^(+)ratio,and root and shoot growth on 12-day-old seedlings under the salt conditions;however,there was no significant difference between the complementation and WT lines.Taken together,these results demonstrate that AtKUP12 might participate in salt tolerance in Arabidopsis through K^(+)uptake and K^(+)/Na^(+)homeostasis.

Surface Metallurgy of Nickle Base Superalloy

The Double Glow Plasma Surface Alloying Technique, the Xu-Tee Process, is a new method to produce high quality alloying layer on the surface of less expensive materials. By using thes technique, the surface alloying layer similar to superalloy Inconel 625 has been obtained on the surface of three kinds of melallic materials (low carbon steel, industrial pure iron, stainless steel Cr18Ni9). The results of the composition and microstructure analyzed by Scanning Electron Microscopy (SEM) and X-Ray Uffrachon (XRD) show that the alloying layer consistS of y matrix and several precipitates (Laves intermetallic phase and carbide etc.). The electrochemical corrosion results show that the surface alloying layer formed on the surface of stainless steel and industrial pure iron have better corrosion resistance than that of nickel base alloy inconel 625 and stainless steel Cr18Ni9 in 3.5%NaCl solution. The exper iments indicate that it is an effective way to obtain the gradient surface alloying layer on the surfaces of steels by using Double Glow Plasma Surface Alloying Technique.

Investigation and Analysis of Harmful Organisms Intercepted from Imported Seeds and Seedlings during 2011-2014

In this study,records published by General Administration of Quality Supervision,Inspection and Quarantine of China and related literature on harmful organisms intercepted from imported seeds and seedlings during 2011-2014 were investigated and analyzed.The results showed that the species and amount of harmful organisms intercepted from imported seeds and seedlings increased gradually during 2011-2014,which posed a realistic or potential threat to agriculture production in China.Based on the present situation,corresponding suggestions and countermeasures were proposed:1 strengthening the study on rapid detection technology of harmful organisms;2 improving the ability of animal and plant quarantine in China.

Nonlinear chirped pulse amplification for a 100-W-class GHz femtosecond all-fiber laser system at 1.5μm

In this work,we present a high-power,high-repetition-rate,all-fiber femtosecond laser system operating at 1.5μm.This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W–the highest average power reported so far from an all-fiber femtosecond laser at 1.5μm,to the best of our knowledge.By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion,the amplified pulses are compressed to 239 fs in an all-fiber configuration.Empowered by such a high-power ultrafast fiber laser system,we further explore the nonlinear interaction among transverse modes LP01,LP11 and LP21 that are expected to potentially exist in fiber laser systems using large-mode-area fibers.The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments.Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.

Transparent glassy composites incorporating lead-free anti-perovskite halide nanocrystals enable tunable emission and ultrastable X-ray imaging

Lead halide perovskite materials exhibit excellent scintillation performance,which,however,suffer from serious stability and toxicity problems.In contrast,the heavy metal-free anti-perovskite materials[MX_(4)]XA_(3)(A=alkali metal;M=transition metal;X=Cl,Br,I),a class of electron-inverted perovskite derivatives,exhibit robust structural and photophysical stability.Here,we design and prepare a lead-free[MnBr_(4)]BrCs_(3) anti-perovskite nanocrystal(NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 Ip mm^(-1).Due to the unique crystal structure and the protection of the glass matrix,the Cs_(3)MnBr_(5) NC-embedded glass exhibits excellent X-ray irradiation stability,thermal stability,and water resistance.These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite.This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.

miR-126-5p affects the chemosensitivity of colorectal cancer cells by regulating SPRED1, ERK1/2 pathway and apoptosis

Chemoresistance is still one of the main obstacles to treat colorectal cancer(CRC).Substantial studies on biomarkers related to chemoresistance have emerged in recent years.Many microRNAs(miRNA)have been reported to involved in drug resistance and CRC.1 MiR-126-5p participates in malignant behaviors of numerous cancers.2,3 However,it is not known if miR-126-5p participates in multidrug resistance in CRC.Especially,the impact of miR-126-5p on drug resistance of CRC and its drug resistance mechanism have not been reported.

Haplotype-resolved and chromosome-level genome assembly of Colorado potato beetle

As the most important non-cereal food crop,potatoes are a staple food for 1.3 billion people(Stokstad,2019).However,these cultivated potatoes are challenged with multiple biotic stresses(i.e.,pathogens and pests),some of which can evade host resistance,leading to a serious dampening of potato yield.One of these pests is the Colorado potato beetle(hereafter referred to as CPB,Leptinotarsa decemlineata Say).CPB is a member of the order Coleoptera,and originated in the southwestern United States and Mexico(Alyokhin et al.,2008).

Aggregated carbon dots-loaded macrophages treat sepsis by eliminating multidrug-resistant bacteria and attenuating inflammation

Sepsis,caused by uncontrollable infection and inflammatory response,leads to more than 30 million infected patients and results in high morbidity worldwide every year.Currently,no efficient approaches have been developed for sepsis therapy due to antimicrobial resistance and inflammatory storm.Here,we report macrophages loaded with aggregated carbon dots(ACDs)in the lysosome,termed MCDs,to treat sepsis in immunosuppressive mice.The ACDs are constructed by negative CDs and amine-abundant polyethyleneimine(PEI),enabling them to bear the strong antibacterial ability and enhanced photoluminescent efficacy.The ACDs are specifically located in the macrophage lysosomes,efficiently enhancing the multidrug-resistant bacteria-killing ability of MCDs.More importantly,the MCDs possess superior anti-inflammatory effects such as reducing the number of pro-inflammatory(M1)and stimulating anti-inflammatory(M2)macrophages.These effects upregulate the inflammatory cytokines(TNF-α,IL-1β,IL-4,and IL-10),ultimately resulting in increased sepsis survival.Our work provides an intelligent approach to overcoming multidrug-resistant bacteria-induced infection from sepsis patients and paves a new avenue on employing nanoparticle-loaded cells for combating inflammation-related infection.

多元微合金化耐火钢研究进展

随着社会经济的不断发展,建筑行业对于建筑材料强度的要求也越来越高,建筑结构用钢的组织类型也由铁素体/珠光体向铁素体/贝氏体、全贝氏体和多相多尺度亚稳(M~3)组织方向发展。耐火钢以其优异的综合性能和良好的耐火安全性等优点,被广泛应用于高层及大跨度建筑中。对于耐火性能的调控方式也从高成本的高Mo(≥0.40%)加单一元素的微合金化为主的方式向经济型的节Mo(≤0.30%)加Nb、V和Ti等多元复合微合金化方式发展。详细介绍了国内外耐火钢的发展历史、产品种类和应用工程以及提高耐火钢室温强度和耐火性能的理论和技术,对比研究了不同组织和微合金元素的耐火性能的差异。研究表明,多元复合微合金化钢在室温和600℃高温的性能要优于单一元素的微合金化钢的性能,因此提出了多元复合微合金纳米碳化物遇火析出增强高温耐火性能的新思路。针对Q345~Q690不同强度级别耐火钢,形成了差异化的合金与组织设计及其热轧/热处理技术,利用扫描电镜(SEM)观察不同强度级别耐火钢的组织类型,阐明了典型多元复合微合金化耐火钢升温-加载过程中显微组织和力学性能的变化规律。采用透射电镜(TEM)、物理化学相分析和三维原子探针(3DAP)等研究方法观察和统计热轧态、不同热处理态和600℃高温拉伸态析出相的分布、尺寸和数量,探讨了纳米碳化物高温沉淀强化、基体组织高温稳定的耐火机理。研究表明,经过弛豫处理的Q345级别钢板为先共析铁素体+少量贝氏体/珠光体组织,具有较高的细晶和沉淀强化增量;轧后直接进行层流冷却的Q345级别钢板为全贝氏体组织,有着较高的位错和固溶强化增量,600℃拉伸的屈服强度(Yield Strength,YS)仍能达到327 MPa。Q460级别钢板为全贝氏体组织,600℃时组织具有良好的高温稳定性,随着在600℃时保温时间的延长,直径小于10 nm的纳米析出相显著增加。Q690级别钢板为马氏体+亚稳奥氏体+纳米析出相和低碳高强贝氏体组织,室温下具有690 MPa的屈服强度和良好的延伸性能,经600℃高温拉伸试验后,其屈服强度不低于室温标准屈服强度的2/3。采用多元微合金化设计、遇火纳米析出强化的调控思路可实现Q345~Q690不同级别耐火钢的耐火功能。

微合金元素对690MPa级耐火钢组织性能的影响

针对690 MPa级空冷贝氏体耐火钢目前存在的屈强比过高无法满足抗震性能,以及冲击韧性过低和高温600℃下屈服强度降低的问题,设计了两种成分的低碳贝氏体耐火钢,分别为低V高Nb+Ti和高V低Nb+Ti两种成分,目的是获得室温屈服强度大于690 MPa,屈强比小于0.85,高温600℃屈服强度大于室温屈服强度的2/3,即460 MPa,以及-40℃低温冲击韧性均值大于69 J的高强韧耐火钢。试验过程中首先在冶炼炉进行冶炼,后将铸锭加热到1200℃以上保温,在900℃左右锻造,锻造完成后采用两阶段控制轧制工艺。为了改善试验钢的力学性能和显微组织,对试验钢采取最终热处理方法,热处理工艺采用正火空冷+回火空冷,正火温度选取Ac3以上30~50℃之间,回火温度采用贝氏体转变温度范围内的温度。对热轧态的试样和经过热处理后的试样进行对比分析,通过金相、扫描等对试样显微组织进行分析,通过常温力学拉伸试验、600℃高温拉伸试验和-40℃低温冲击试验,对试验钢的力学性能进行对比分析,同时对微合金元素Nb、V、Ti对过冷奥氏体连续冷却转变曲线(CCT曲线)的影响进行了研究分析。结果表明:通过微合金元素Nb、V、Ti的调整,能使F+P转变线明显右移,贝氏体转变线趋于扁平化,组织由原来的粒状贝氏体转变为粒状贝氏体与板条贝氏体的混合组织。通过增加V,降低Nb+Ti的含量,对热轧态的组织对比,发现可以获得的粒状贝氏体组织中M-A岛更加细小均匀,更有利于改善材料的塑韧性。对热处理后的试验钢的组织和性能进行对比发现,通过增加V,降低Nb+Ti的含量,组织由粒状贝氏体转变为粒状贝氏体与板条贝氏体的混合组织,而板条贝氏体对试验钢的力学性能有利。Y1试验钢中大块的粒状贝氏体组织对试验钢的低温冲击韧性不利,Y2试验钢中细小的粒状与板条状贝氏体的混合组织,能显著改善试验钢的冲击韧性。因此,在实际生产中,应尽量获得细化的板条贝氏体组织才能使材料的性能更好。与此同时,对比相同成分的热处理后的试验钢发现,回火温度对试验钢的屈服强度的影响更为明显,对抗拉强度影响较小,通过采取合理的调控回火温度,发现Y1试验钢在350℃时力学性能最佳,但高温屈服强度和低温冲击韧性不理想,而Y2试验钢在400℃时力学性能最佳。综上所述,Y2经过正火+400℃回火、1 h热处理工艺后具有优秀的综合性能,即抗拉强度为1009 MPa、屈服强度为855 MPa,600℃的屈服强度为481 MPa,满足屈服强度大于室温屈服强度的2/3,-40℃冲击功均值为145 J,大于69 J,满足690 MPa级耐火钢的要求。

Noise-sidebands-free and ultra-low-RIN 1.5 μm single-frequency fiber laser towards coherent optical detection

A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a booster optical amplifier, the noise sidebands with relative amplitudes as high as 20 dB are completely suppressed.The RIN is remarkably reduced by more than 64 dB at the relaxation oscillation peak to retain below-150 dB∕Hz in a frequency range from 75 kHz to 50 MHz, while the quantum noise limit is -152.9 d B∕Hz.Furthermore, a laser linewidth narrower than 600 Hz, a polarization-extinction ratio of more than 23 dB, and an optical signal-to-noise ratio of more than 73 dB are acquired simultaneously. This noise-sidebands-free and ultralow-RIN single-frequency fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.

Genomics Approaches to Domestication Studies of Horticultural Crops

The majority of crops we eat today are derived from the domestication of their wild progenitors. Crop domestication satisfies the human need for food and nutrition. Characterization of the history and genetic basis of crop domestication is essential for us to conduct modern breeding practices. Genomics provide unprecedented opportunities for us to study domestication. In this review, the typical domestication syndromes of horticultural crops will be introduced. Using the tomato as a typical example, we will discuss how genetic and genomic data were used to decipher the origins, progenitors, and domestication processes of this crop. In the domestication exploration of the genetic basis especially,genome-scaled diversity scanning approaches have gained great popularity. Combining these approaches with QTL(Quantitative trait locus)-mapping, GWAS(Genome wide association study), metabolomics and homology-based searches as well as pan-genomics have demonstrated tremendous advantages and significantly contribute to our understanding of domestication. Genomics studies will accelerate domestication research and further breeding of crops.

Multi-functional bismuth-doped bioglasses: combining bioactivity and photothermal response for bone tumor treatment and tissue repair

Treatment of large bone defects derived from bone tumor surgery is typically performed in multiple separate operations,such as hyperthermia to extinguish residual malignant cells or implanting bioactive materials to initiate apatite remineralization for tissue repair;it is very challenging to combine these functions into a material.Herein,we report the first photothermal(PT)effect in bismuth(Bi)-doped glasses.On the basis of this discovery,we have developed a new type of Bi-doped bioactive glass that integrates both functions,thus reducing the number of treatment cycles.We demonstrate that Bi-doped bioglasses(BGs)provide high PT efficiency,potentially facilitating photoinduced hyperthermia and bioactivity to allow bone tissue remineralization.The PT effect of Bi-doped BGs can be effectively controlled by managing radiative and non-radiative processes of the active Bi species by quenching photoluminescence(PL)or depolymerizing glass networks.In vitro studies demonstrate that such glasses are biocompatible to tumor and normal cells and that they can promote osteogenic cell proliferation,differentiation,and mineralization.Upon illumination with near-infrared(NIR)light,the bioglass(BG)can efficiently kill bone tumor cells,as demonstrated via in vitro and in vivo experiments.This indicates excellent potential for the integration of multiple functions within the new materials,which will aid in the development and application of novel biomaterials.

High-efficiency and high-power single-frequency fiber laser at 1.6μm based on cascaded energy-transfer pumping

In this paper,a technique combining the cascaded energy-transfer pumping(CEP)method and master-oscillator power-amplifier(MOPA)configuration is proposed for power scaling of 1.6-μm-band single-frequency fiber lasers(SFFLs),where the Er^(3+)ion has a limited gain.The CEP technique is fulfilled by coupling a primary signal light at 1.6μm and a C-band auxiliary laser.The numerical model of the fiber amplifier with the CEP technique reveals that the energy transfer process involves the pump competition and the in-band particle transition between the signal and auxiliary lights.Moreover,for the signal emission,the population density in the upper level is enhanced,and the effective population inversion is achieved thanks to the CEP.A single-frequency MOPA laser at 1603 nm with an output power of 52.6 W and an improved slope efficiency of 30.4%is experimentally obtained through the CEP technique.Besides,a laser linewidth of 5.2 k Hz and a signal-to-auxiliary laser ratio of 60.7 d B are obtained at the maximum output power.The proposed technique is anticipated to be promising for increasing the slope efficiency and power scaling for fiber lasers operating at L band.

Three-level all-fiber laser at 915 nm based on polarization-maintaining Nd^3+-doped silica fiber

Nd3+-doped fiber lasers at around 900 nm based on the 4F3/2→4I9/2 transition have obtained much research attention since they can be used as the laser sources for generating pure blue fiber lasers through the frequency doubling.Here,an all-fiber laser at 915 nm was realized by polarization-maintaining Nd3+-doped silica fiber.A net gain per unit length of up to 1.0 dB/cm at 915 nm was obtained from a 4.5 cm fiber,which to our best knowledge is the highest gain coefficient reported in this kind of silica fiber.The optical-to-optical conversion efficiency varies with the active fiber length and the reflectivity of the output fiber Bragg grating(FBG),presenting an optimal value of 5.3%at 5.1 cm fiber length and 70%reflectivity of the low reflection FBG.Additionally,the linear distributed Bragg reflector short cavity was constructed to explore its potential in realizing single-frequency 915 nm fiber laser.The measurement result of longitudinal-mode properties shows it is still multi-longitudinal mode laser operation with 40 mm laser cavity.These results indicate that the Nd3+-doped silica fiber could be used to realize all-fiber laser at 915 nm,which presents potential to be the seed source of high-power fiber laser.

In situ instant generation of an ultrabroadband near-infrared emission center in bismuth-doped borosilicate glasses via a femtosecond laser

Bismuth(Bi)-doped photonic materials, which exhibit broadband near-infrared(NIR) luminescence(1000–1600 nm), are evolving into interesting gain media. However, the traditional methods have shown their limitations in enhancing Bi NIR emission, especially in the microregion. Consequently, the typical NIR emission has seldom been achieved in Bi-doped waveguides, which highly restricts the application of Bi-activated materials.Here, superbroadband Bi NIR emission is induced in situ instantly in the grating region by a femtosecond(fs)laser inside borosilicate glasses. A series of structural and spectroscopic characterizations are summoned to probe the generation mechanism. And we show how this novel NIR emission in the grating region can be enhanced significantly and erased reversibly. Furthermore, we successfully demonstrate Bi-activated optical waveguides.These results present new insights into Bi-doped materials and push the development of broadband waveguide amplification.

Experimental demonstration of transverse mode instability enhancement by a counter-pumped scheme in a 2 kW all-fiberized laser

Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals TMI threshold enhancement through a semi-analytical model calculation.We demonstrated a 2 kW high-power counter-pumped all-fiberized laser without observation of TMI.Compared with the co-pumped scheme,the TMI threshold is enhanced at least 50%in counter-pumped scheme,moreover,stimulated Raman scattering and four-wave mixing are suppressed simultaneously.

用于偏振光探测的自组装超细CsPbBr_(3)钙钛矿纳米线

一维金属卤化物钙钛矿纳米线因具有较高的吸收和发射效率、较大的介电常数以及各向异性的光电特性等优势而在能源收集、柔性电子和生物成像设备等领域展现出潜在的应用价值.本论文提出了一种改进的两步溶剂热法用于制备自组装的立方相CsPbBr_(3)纳米线阵列,为获得连续均匀的超细钙钛矿纳米线和有序排列的纯钙钛矿纳米线阵列提供了一个更为简便的方法.在365 nm紫外光的激发下,肉眼可见地观测到来自CsPbBr_(3)纳米线的蓝光发射.同时,在800 nm脉冲激光的激发下,CsPbBr_(3)纳米线也表现出较强的双光子发射.改变800 nm脉冲激光的偏振方向,可以发现,CsPbBr_(3)纳米线虽然具有各向同性的立方结构,但其自组装的纳米线阵列仍表现出较强的偏振依赖性,偏振度达到0.49.基于密度泛函理论计算,CsPbBr_(3)纳米线阵列的偏振依赖发射与其各向异性的电荷密度分布有关.上述结果表明具有良好自组装特性的超细CsPbBr_(3)钙钛矿纳米线有望用于下一代偏振敏感光电探测器件.

Correction:Multi-functional bismuth-doped bioglasses:combining bioactivity and photothermal response for bone tumor treatment and tissue repair

In this originally published article,we have noticed several mistakes.They should be corrected as follows:1.On page 1,the second affiliation(No.5)of the author“Chuanbin Mao”should be deleted as he does not belong to that affiliation.Namely,he should be only listed with(Department of Chemistry and Biochemistry Stephenson Life Sciences Research Center,University of Oklahoma,Norman,OK 73072,USA).

Tailoring microstructure and electrical transportation through tensile stress in Bi_(2)Te_(3) thermoelectric fibers

Bismuth telluride(Bi_(2)Te_(3))has attracted much attention in the field of thermoelectrics since it is one kind of commercial room-temperature thermoelectric material.Herein three kinds of Bi_(2)Te_(3) thermoelectric fibers with internal tensile stress are fabricated utilizing an optical fiber template method.The effects of internal stress on the microstructure and the electrical transportation of Bi_(2)Te_(3) thermoelectric fibers are investigated.The Bi_(2)Te_(3) cores in the fibers are highly crystalline and possess a tensile nanosheet structure with preferential orientation as evidenced by X-ray diffraction and Raman studies.Tensile stress can enhance electrical properties of the fibers.And a paper cup generator covered with 20 pieces of optimized fibers provides a μW-level output power.It is inferred that tensile stress tuning can be an effective tool for the material optimization of thermoelectric performance.