W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a po...W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.展开更多
As femtosecond(fs)laser machining advances from micro/nanoscale to macroscale,approaches capable of machining macroscale geometries that sustain micro/nanoscale precisions are in great demand.In this research,an fs la...As femtosecond(fs)laser machining advances from micro/nanoscale to macroscale,approaches capable of machining macroscale geometries that sustain micro/nanoscale precisions are in great demand.In this research,an fs laser sharp shaping approach was developed to address two key challenges in macroscale machining(i.e.defects on edges and tapered sidewalls).The evolution of edge sharpness(edge transition width)and sidewall tapers were systematically investigated through which the dilemma of simultaneously achieving sharp edges and vertical sidewalls were addressed.Through decreasing the angle of incidence(AOI)from 0◦to−5◦,the edge transition width could be reduced to below 10µm but at the cost of increased sidewall tapers.Furthermore,by analyzing lateral and vertical ablation behaviors,a parameter-compensation strategy was developed by gradually decreasing the scanning diameters along depth and using optimal laser powers to produce non-tapered sidewalls.The fs laser ablation behaviors were precisely controlled and coordinated to optimize the parameter compensations in general manufacturing applications.The AOI control together with the parameter compensation provides a versatile solution to simultaneously achieve vertical sidewalls as well as sharp edges of entrances and exits for geometries of different shapes and dimensions.Both mm-scale diameters and depths were realized with dimensional precisions below 10µm and surface roughness below 1µm.This research establishes a novel strategy to finely control the fs laser machining process,enabling the fs laser applications in macroscale machining with micro/nanoscale precisions.展开更多
The concept of multi-principal component has created promising opportunities for the development of novel high-entropy ceramics for extreme environments encountered in advanced turbine engines, nuclear reactors, and h...The concept of multi-principal component has created promising opportunities for the development of novel high-entropy ceramics for extreme environments encountered in advanced turbine engines, nuclear reactors, and hypersonic vehicles, as it expands the compositional space of ceramic materials with tailored properties within a single-phase solid solution. The unique physical properties of some high-entropy carbides and borides, such as higher hardness, high-temperature strength, lower thermal conductivity, and improved irradiation resistance than the constitute ceramics, have been observed. These promising properties may be attributed to the compositional complexity, atomic-level disorder, lattice distortion, and other fundamental processes related to defect formation and phonon scattering.This manuscript serves as a critical review of the recent progress in high-entropy carbides and borides, focusing on synthesis and evaluations of their performance in extreme high-temperature, irradiation, and gaseous environments.展开更多
回顾性分析青岛大学附属医院1例COQ2基因突变所致的原发性辅酶Q10缺乏症患儿的临床特征及基因突变特点,提高对该疾病的认识。收集患儿临床资料,基因测序明确患儿基因突变并进行分析。患儿,男,1岁8个月,以激素耐药型肾病综合征为临床表型...回顾性分析青岛大学附属医院1例COQ2基因突变所致的原发性辅酶Q10缺乏症患儿的临床特征及基因突变特点,提高对该疾病的认识。收集患儿临床资料,基因测序明确患儿基因突变并进行分析。患儿,男,1岁8个月,以激素耐药型肾病综合征为临床表型,低蛋白血症难以纠正,水肿进行性加重。基因检测发现存在COQ2基因复合杂合突变,分别为COQ2基因c.854A>G突变(来自母亲)和c.912+1 del G突变(来自父亲);肾活检病理结果为局灶节段性肾小球硬化。诊断为COQ2基因突变导致的原发性辅酶Q10缺乏症。COQ2基因突变导致的原发性辅酶Q10缺乏症可仅表现为激素耐型肾病综合征,病理类型多为局灶节段性肾小球硬化,早期大剂量补充外源性辅酶Q10可能有良好的临床疗效。展开更多
In this work,we demonstrate that ultraviolet(UV)laser photolysis of hydrocarbon species alters the flame chemistry such that it promotes the diamond growth rate and film quality.Optical emission spectroscopy and laser...In this work,we demonstrate that ultraviolet(UV)laser photolysis of hydrocarbon species alters the flame chemistry such that it promotes the diamond growth rate and film quality.Optical emission spectroscopy and laser-induced fluorescence demonstrate that direct UV laser irradiation of a diamond-forming combustion flame produces a large amount of reactive species that play critical roles in diamond growth,thereby leading to enhanced diamond growth.The diamond growth rate is more than doubled,and diamond quality is improved by 4.2%.Investigation of the diamond nucleation process suggests that the diamond nucleation time is significantly shortened and nondiamond carbon accumulation is greatly suppressed with UV laser irradiation of the combustion flame in a laser-parallel-to-substrate geometry.A narrow amorphous carbon transition zone,averaging 4 nm in thickness,is identified at the film–substrate interface area using transmission electron microscopy,confirming the suppression effect of UV laser irradiation on nondiamond carbon formation.The discovery of the advantages of UV photochemistry in diamond growth is of great significance for vastly improving the synthesis of a broad range of technically important materials.展开更多
Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive...Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive.Here,a pan-cancer transcriptomic screening for 10852 samples of 33 TCGA cancer types reveals that cAMP-responsive element(CRE)transcription factors are convergent activators for cancer stemness.Deconvolution of transcriptomic profiles,specification of neural markers and illustration of norepinephrine dynamics uncover a bond between TME neural signals and cancer-cell CRE activity.Specifically,neural signal norepinephrine potentiates the stemness of proximal cancer cells by activating cAMP-CRE axis,where ATF1 serves as a conserved hub.Upon activation by norepinephrine,ATF1 potentiates cancer stemness by coordinated trans-activation of both nuclear pluripotency factors MYC/NANOG and mitochondrial biogenesis regulators NRF1/TFAM,thereby orchestrating nuclear reprograming and mitochondrial rejuvenating.Accordingly,single-cell transcriptomes confirm the coordinated activation of nuclear pluripotency with mitochondrial biogenesis in cancer stem-like cells.These findings elucidate that cancer cell acquires stemness via a norepinephrine-ATF1 driven nucleus-mitochondria collaborated program,suggesting a spatialized stemness acquisition by hijacking microenvironmental neural signals.展开更多
基金supported by the National Science Foundation under Grant No.CMMI-1762190The research was performed in part in the Nebraska Nanoscale Facility:National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Materials and Nanoscience (and/or NERCF),which are supported by the National Science Foundation under Award ECCS:2025298+1 种基金the Nebraska Research Initiativesupported by the U.S.Department of Energy,Office of Nuclear Energy under DOE Idaho Operations Office Contract DE-AC07-051D14517 as part of a Nuclear Science User Facilities experiment。
文摘W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.
基金This study was supported by the National Science Foundation(CMMI 1826392)and the Nebraska Center for Energy Sci-ences Research(NCESR)The research was performed in part in the Nebraska Nanoscale Facility:National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Mater-ials and Nanoscience,which are supported by the National Sci-ence Foundation under Award ECCS:1542182,and the Neb-raska Research Initiative.
文摘As femtosecond(fs)laser machining advances from micro/nanoscale to macroscale,approaches capable of machining macroscale geometries that sustain micro/nanoscale precisions are in great demand.In this research,an fs laser sharp shaping approach was developed to address two key challenges in macroscale machining(i.e.defects on edges and tapered sidewalls).The evolution of edge sharpness(edge transition width)and sidewall tapers were systematically investigated through which the dilemma of simultaneously achieving sharp edges and vertical sidewalls were addressed.Through decreasing the angle of incidence(AOI)from 0◦to−5◦,the edge transition width could be reduced to below 10µm but at the cost of increased sidewall tapers.Furthermore,by analyzing lateral and vertical ablation behaviors,a parameter-compensation strategy was developed by gradually decreasing the scanning diameters along depth and using optimal laser powers to produce non-tapered sidewalls.The fs laser ablation behaviors were precisely controlled and coordinated to optimize the parameter compensations in general manufacturing applications.The AOI control together with the parameter compensation provides a versatile solution to simultaneously achieve vertical sidewalls as well as sharp edges of entrances and exits for geometries of different shapes and dimensions.Both mm-scale diameters and depths were realized with dimensional precisions below 10µm and surface roughness below 1µm.This research establishes a novel strategy to finely control the fs laser machining process,enabling the fs laser applications in macroscale machining with micro/nanoscale precisions.
基金funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0001428supported by the National Science Foundation under Award ECCS: 2025298the Nebraska Research Initiative。
文摘The concept of multi-principal component has created promising opportunities for the development of novel high-entropy ceramics for extreme environments encountered in advanced turbine engines, nuclear reactors, and hypersonic vehicles, as it expands the compositional space of ceramic materials with tailored properties within a single-phase solid solution. The unique physical properties of some high-entropy carbides and borides, such as higher hardness, high-temperature strength, lower thermal conductivity, and improved irradiation resistance than the constitute ceramics, have been observed. These promising properties may be attributed to the compositional complexity, atomic-level disorder, lattice distortion, and other fundamental processes related to defect formation and phonon scattering.This manuscript serves as a critical review of the recent progress in high-entropy carbides and borides, focusing on synthesis and evaluations of their performance in extreme high-temperature, irradiation, and gaseous environments.
文摘回顾性分析青岛大学附属医院1例COQ2基因突变所致的原发性辅酶Q10缺乏症患儿的临床特征及基因突变特点,提高对该疾病的认识。收集患儿临床资料,基因测序明确患儿基因突变并进行分析。患儿,男,1岁8个月,以激素耐药型肾病综合征为临床表型,低蛋白血症难以纠正,水肿进行性加重。基因检测发现存在COQ2基因复合杂合突变,分别为COQ2基因c.854A>G突变(来自母亲)和c.912+1 del G突变(来自父亲);肾活检病理结果为局灶节段性肾小球硬化。诊断为COQ2基因突变导致的原发性辅酶Q10缺乏症。COQ2基因突变导致的原发性辅酶Q10缺乏症可仅表现为激素耐型肾病综合征,病理类型多为局灶节段性肾小球硬化,早期大剂量补充外源性辅酶Q10可能有良好的临床疗效。
基金the financial support from the National Science Foundation(CMMI 1265122)the Nebraska Center for Energy Sciences Research(NCESR).
文摘In this work,we demonstrate that ultraviolet(UV)laser photolysis of hydrocarbon species alters the flame chemistry such that it promotes the diamond growth rate and film quality.Optical emission spectroscopy and laser-induced fluorescence demonstrate that direct UV laser irradiation of a diamond-forming combustion flame produces a large amount of reactive species that play critical roles in diamond growth,thereby leading to enhanced diamond growth.The diamond growth rate is more than doubled,and diamond quality is improved by 4.2%.Investigation of the diamond nucleation process suggests that the diamond nucleation time is significantly shortened and nondiamond carbon accumulation is greatly suppressed with UV laser irradiation of the combustion flame in a laser-parallel-to-substrate geometry.A narrow amorphous carbon transition zone,averaging 4 nm in thickness,is identified at the film–substrate interface area using transmission electron microscopy,confirming the suppression effect of UV laser irradiation on nondiamond carbon formation.The discovery of the advantages of UV photochemistry in diamond growth is of great significance for vastly improving the synthesis of a broad range of technically important materials.
基金This research work was supported by the National Key R&D Program of China(2019YFA0110300 to Q.L.)the National Natural Science Foundation of China(No.82003096 to R.G.,No.82002943 to B.H.,No.81820108024 to Q.L.and No.81972594 to M.Y.)+1 种基金the Natural Science Foundation of Guangdong(2017A030313608 to Q.L.)the Science and Technology Planning Project of Guangzhou(201804020044 to Q.L.).
文摘Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive.Here,a pan-cancer transcriptomic screening for 10852 samples of 33 TCGA cancer types reveals that cAMP-responsive element(CRE)transcription factors are convergent activators for cancer stemness.Deconvolution of transcriptomic profiles,specification of neural markers and illustration of norepinephrine dynamics uncover a bond between TME neural signals and cancer-cell CRE activity.Specifically,neural signal norepinephrine potentiates the stemness of proximal cancer cells by activating cAMP-CRE axis,where ATF1 serves as a conserved hub.Upon activation by norepinephrine,ATF1 potentiates cancer stemness by coordinated trans-activation of both nuclear pluripotency factors MYC/NANOG and mitochondrial biogenesis regulators NRF1/TFAM,thereby orchestrating nuclear reprograming and mitochondrial rejuvenating.Accordingly,single-cell transcriptomes confirm the coordinated activation of nuclear pluripotency with mitochondrial biogenesis in cancer stem-like cells.These findings elucidate that cancer cell acquires stemness via a norepinephrine-ATF1 driven nucleus-mitochondria collaborated program,suggesting a spatialized stemness acquisition by hijacking microenvironmental neural signals.
