The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytot...The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.展开更多
Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces ...Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.展开更多
The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN subs...The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off(LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of(002) and(102) planes, alongside a low dislocation density of 1.6 × 10^(6) cm^(-2). This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics.展开更多
Ultraviolet(UV) photodetectors(PDs) have drawn great attention in recent years due to their potential application in civil and military fields. Because of its ultrawide bandgap, low cost, strong radiation hardness, an...Ultraviolet(UV) photodetectors(PDs) have drawn great attention in recent years due to their potential application in civil and military fields. Because of its ultrawide bandgap, low cost, strong radiation hardness, and high thermal and chemical stability with high visible-light transparency, Ga_2O_3 is regarded as the most promising candidate for UV detection.Furthermore, the bandgap of Ga_2O_3 is as high as 4.7–4.9 eV, directly corresponding to the solar-blind UV detection band with wavelength less than 280 nm. There is no need of doping in Ga_2O_3 to tune its bandgap, compared to AlGaN, MgZnO,etc, thereby avoiding alloy composition fluctuations and phase separation. At present, solar-blind Ga_2O_3 photodetectors based on single crystal or amorphous Ga_2O_3 are mainly focused on metal–semiconductor–metal and Schottky photodiodes.In this work, the recent achievements of Ga_2O_3 photodetectors are systematically reviewed. The characteristics and performances of different photodetector structures based on single crystal Ga_2O_3 and amorphous Ga_2O_3 thin film are analyzed and compared. Finally, the prospects of Ga_2O_3 UV photodetectors are forecast.展开更多
A series of experimental results of field-reversed configurations(FRCs) on a KMAX(Keda Mirror with AXisymmetricity) tandem mirror machine are reported.Single-side FRC translation processes with three different gas spe...A series of experimental results of field-reversed configurations(FRCs) on a KMAX(Keda Mirror with AXisymmetricity) tandem mirror machine are reported.Single-side FRC translation processes with three different gas species were measured by avalanche photodiodes.Consistent with the theoretical prediction, the measured FRC speeds were inversely proportional to the square root of the ion mass.However, the speeds of the hydrogen FRC increased even in a uniform magnetic field region while the speeds of the helium and argon FRCs decreased.Possible mechanisms are discussed.The speed of the second pass due to the reflection of the mirror fields was found to be ~1/3 of the first pass speed.The internal magnetic fields were measured for a colliding-merging argon FRC, and the results show that, even for very slowmoving FRCs, merging can occur.展开更多
Large accelerator facilities require clocks and triggers with high accuracy to synchronize equipment and devices. A new femtosecond timing system was designed to meet the demands of new facilities. In this system, the...Large accelerator facilities require clocks and triggers with high accuracy to synchronize equipment and devices. A new femtosecond timing system was designed to meet the demands of new facilities. In this system, the radio-frequency signal is modulated in a continuous-wave laser carrier with frequency stabilization, and timing events are distributed in the same fiber. The phase drift is detected precisely, based on the principle of the Michelson interferometer. The phase drift is compensated with coarse and fine correctors afterward. We aim to realize the stable transmission of the RF signal and timing events for a long distance and duration, with the phase drift and additive jitter in femtoseconds. After the extension, the system will become a complete solution for the clock-and-trigger distribution of synchrotron radiation facilities, free-electron lasers, and other accelerators. The physics design, simulation analysis, and preliminary results are included in the paper.展开更多
AIM:To evaluate the effect of bone morphogenetic protein-6(BMP-6)on transforming growth factor(TGF)-β_(2)-induced epithelial-mesenchymal transition(EMT)in retinal pigment epithelium(RPE).METHODS:Adult retinal pigment...AIM:To evaluate the effect of bone morphogenetic protein-6(BMP-6)on transforming growth factor(TGF)-β_(2)-induced epithelial-mesenchymal transition(EMT)in retinal pigment epithelium(RPE).METHODS:Adult retinal pigment epithelial cell line(ARPE-19)were randomly divided into control,TGF-β_(2)(5μg/L),and BMP-6 small interfering RNA(siRNA)group.The cell morphology was observed by microscopy,and the cell migration ability were detected by Transwell chamber.The EMT-related indexes and BMP-6 protein levels were detected by Western blotting.Furthermore,a BMP-6 overexpression plasmid was constructed and RPE cells were divided into the control group,TGF-β_(2)+empty plasmid group,BMP-6 overexpression group,and TGF-β_(2)+BMP-6 overexpression group.The EMT-related indexes and extracellular regulated protein kinases(ERK)protein levels were detected.RESULTS:Compared with the control group,the migration of RPE cells in the TGF-β_(2) group was significantly enhanced.TGF-β_(2) increased the protein expression levels ofα-smooth muscle actin(α-SMA),fibronectin and vimentin but significantly decreased the protein levels of E-cadherin and BMP-6(P<0.05)in RPE.Similarly,the migration of RPE cells in the BMP-6 siRNA group was also significantly enhanced.BMP-6 siRNA increased the protein expression levels ofα-SMA,fibronectin and vimentin but significantly decreased the protein expression levels of E-cadherin(P<0.05).Overexpression of BMP-6 inhibited the migration of RPE cells induced by TGF-β_(2) and prevented TGF-β_(2) from affecting EMT-related biomarkers(P<0.05).CONCLUSION:BMP-6 prevents the EMT in RPE cells induced by TGF-β_(2),which may provide a theoretical basis for the prevention and treatment of proliferative vitreoretinopathy.展开更多
0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,...0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.展开更多
Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research probl...Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research problem.Previous studies relied on statistical regression models that failed to capture the complex nonlinear relationships between carbon emissions and characteristic variables.In this study,we propose a machine learning algorithm for carbon emissions,a Bayesian optimized XGboost regression model,using multi-year energy carbon emission data and nighttime lights(NTL)remote sensing data from Shaanxi Province,China.Our results demonstrate that the XGboost algorithm outperforms linear regression and four other machine learning models,with an R^(2)of 0.906 and RMSE of 5.687.We observe an annual increase in carbon emissions,with high-emission counties primarily concentrated in northern and central Shaanxi Province,displaying a shift from discrete,sporadic points to contiguous,extended spatial distribution.Spatial autocorrelation clustering reveals predominantly high-high and low-low clustering patterns,with economically developed counties showing high-emission clustering and economically relatively backward counties displaying low-emission clustering.Our findings show that the use of NTL data and the XGboost algorithm can estimate and predict carbon emissionsmore accurately and provide a complementary reference for satellite remote sensing image data to serve carbon emission monitoring and assessment.This research provides an important theoretical basis for formulating practical carbon emission reduction policies and contributes to the development of techniques for accurate carbon emission estimation using remote sensing data.展开更多
Objective This systematic review aimed to identify the predictors of recovery from dysphagia after stroke in the last ten years,thereby providing an evidence-based basis for nurses to identify high-risk patients and d...Objective This systematic review aimed to identify the predictors of recovery from dysphagia after stroke in the last ten years,thereby providing an evidence-based basis for nurses to identify high-risk patients and develop individualized rehabilitation plans to improve patient prognosis.Methods Databases including the China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBMdisc),China Science and Technology Journal(VIP),WanFang,PubMed,Embase,CINAHL,Web of Science,the Cochrane Library,and Scopus were retrieved to search for literature on the predictors of recovery from dysphagia after stroke.The retrieval period was from January 2013 to December 2023.The quality of studies was assessed using the Newcastle-Ottawa Scale(NOS)and the Prediction model Risk of Bias Assessment Tool(PROBAST).Meta-analysis was performed using Revman5.3 and Stata15.1 software.The review protocol has been registered with PROSPERO(CRD42024605570).Results A total of 1,216 results were obtained,including 599 in English and 617 in Chinese.A total of 34 studies were included,involving 156,309 patients with post-stroke dysphagia,and the rate of dysphagia recovery increased from 13.53%at 1 week to 95%at 6 months after stroke.Meta-analysis results showed that older age[OR=1.06,95%CI(1.04,1.08),P<0.001],lower BMI[OR=1.28,95%CI(1.17,1.40),P<0.001],bilateral stroke[OR=3.10,95%CI(2.04,4.72),P<0.001],higher National Institutes of Health Stroke Scale(NIHSS)score[OR=1.19,95%CI(1.01,1.39),P=0.030],tracheal intubation[OR=5.08,95%CI(1.57,16.39),P=0.007]and aspiration[OR=4.70,95%CI(3.06,7.20),P<0.001]were unfavorable factors for the recovery of swallowing function in patients with post-stroke dysphagia.Conclusions The lack of standardized criteria for rehabilitation assessment of post-stroke dysphagia has resulted in reported recovery rates of swallowing function exhibiting wide variability.Nurses should take targeted preventive measures for patients aged≥70 years,low BMI,bilateral stroke,high NIHSS score,tracheal intubation,and aspiration to promote the recovery of swallowing function in patients with post-stroke dysphagia.展开更多
Composite solid electrolytes(CSEs)are considered among the most promising candidates for solid-state batteries.However,their practical application is hindered by low ionic conductivity and a limited lithium-ion transf...Composite solid electrolytes(CSEs)are considered among the most promising candidates for solid-state batteries.However,their practical application is hindered by low ionic conductivity and a limited lithium-ion transference number,primarily owing to the insufficient mobility of Li+.In this work,we design a heterojunc-tion nanoparticle composed of bimetallic zeolitic imidazolate frameworks(ZIFs)coupled with amorphous tita-nium oxide(TiO_(2)@Zn/Co–ZIF)as a filler to fabricate a composite solid-state electrolyte(PVZT).The amor-phous TiO_(2) coating facilitates salt dissociation through Lewis acid–base interactions with the anions of the lithium salt.Meanwhile,the Zn/Co–ZIF framework not only provides additional selective pathways for Li+transport but also effectively restricts anion migration through its confined pore size.The synergistic effect results in a high room-temperature ionic conductivity(8.8×10^(-4) S·cm^(-1))and a lithium-ion transference number of 0.47 for PVZT.A symmetrical cell using PVZT demonstrates stable Li+deposition/stripping for over 1100 h at a current density of 0.1 mA·cm^(-2).Additionally,a LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li full cell using PVZT retains 75.0%of its capacity after 1200 cycles at a 2 C rate.This work offers valuable insights into the design of func-tional fillers for CSEs with highly efficient ion transport.展开更多
Background:The aim was to elucidate the function of IL-37 in middle east respiratory syndrome coronavirus(MERS-CoV)infection,thereby providing a novel therapeutic strategy for managing the clinical treatment of inflam...Background:The aim was to elucidate the function of IL-37 in middle east respiratory syndrome coronavirus(MERS-CoV)infection,thereby providing a novel therapeutic strategy for managing the clinical treatment of inflammatory response caused by respiratory virus infection.Methods:We investigated the development of MERS by infecting hDPP4 mice with hCoV-EMC(107 TCID50[50%tissue culture infectious dose])intranasally.We infected A549 cells with MERS-CoV,which concurrently interfered with IL-37,detecting the viral titer,viral load,and cytokine expression at certain points postinfection.Meanwhile,we administered IL-37(12.5μg/kg)intravenously to hDPP4 mice 2 h after MERS-CoV-2 infection and collected the serum and lungs 5 days after infection to investigate the efficacy of IL-37 in MERS-CoV infection.Results:The viral titer of MERS-CoV-infected A549 cells interfering with IL-37 was significantly reduced by 4.7-fold,and the viral load of MERS-CoV-infected hDPP4 mice was decreased by 59-fold in lung tissue.Furthermore,the administration of IL-37 suppressed inflammatory cytokine and chemokine(monocyte chemoattractant protein 1,interferon-γ,and IL-17A)expression and ameliorated the infiltration of inflammatory cells in hDPP4 mice.Conclusion:IL-37 exhibits protective properties in severe pneumonia induced by MERS-CoV infection.This effect is achieved through attenuation of lung viral load,suppression of inflammatory cytokine secretion,reduction in inflammatory cell infiltration,and mitigation of pulmonary injury.展开更多
目的:探讨保留肝实质的治疗方式在结直肠癌肝转移(colorectal liver metastases,CRLM)手术切除中的意义。方法:回顾性分析北京大学肿瘤医院2000年1月至2016年5月手术切除的CRLM患者377例,根据手术方式分为保留肝实质(parenchymalsparing...目的:探讨保留肝实质的治疗方式在结直肠癌肝转移(colorectal liver metastases,CRLM)手术切除中的意义。方法:回顾性分析北京大学肿瘤医院2000年1月至2016年5月手术切除的CRLM患者377例,根据手术方式分为保留肝实质(parenchymalsparing hepatectomy,PSH)组305例和大范围肝切除(major hepatectomy,MH)组72例。比较两组患者的临床特征、手术情况、术后并发症及预后。结果:PSH组肝转移灶个数少于MH组,差异比较具有统计学意义(P=0.000)。全组采用PSH治疗的患者占80.9%,且随时间增长逐渐增多。PSH组手术时间比MH组短(177.5 min vs.220 min,P=0.000),手术出血比MH组少(150 m L vs.300 m L,P=0.000),术后并发症发生率比MH组低(47.4%vs.64.8%,P=0.008)。PSH组与MH组患者的总生存(overall survival,OS)时间、肝内无复发生存(hepatic recurrence free survival,HFRS)时间差异无统计学意义。PSH组患者复发后接受局部治疗的比例明显增加(42.8%vs.25.6%,P=0.040),复发患者中接受局部治疗的患者生存期明显延长(58个月vs.24个月,P=0.000)。结论:CRLM患者手术时采用PSH的治疗方式肝内复发率更低,安全性更高,复发后再次接受局部治疗的可能性明显增加,是推荐的治疗模式。展开更多
Based on questionnaire surveys and field interviews conducted with various types of agricultural production organizations across five districts and four counties in Daqing City,this study combines relevant theoretical...Based on questionnaire surveys and field interviews conducted with various types of agricultural production organizations across five districts and four counties in Daqing City,this study combines relevant theoretical frameworks to systematically examine the evolution,performance,and influencing factors of governance mechanisms within these organizations.Using both quantitative and inductive analytical methods,the paper proposes innovative designs and supporting measures for improving governance mechanisms.The findings reveal that,amid large-scale farmland circulation,the governance mechanisms of agricultural production organizations in Daqing City are evolving from traditional to modern structures.However,challenges remain in areas such as decision-making efficiency,benefit distribution,and supervision mechanisms.In response,this study proposes innovative governance designs focusing on decision-making processes,profit-sharing mechanisms,and risk prevention.Corresponding policy recommendations are also provided to support the sustainable development of agricultural modernization in China.展开更多
Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)mole...Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)molecular dynamics(MD)simulation offers a microscopic angle to view the self-assembly of BCPs.Although some molecular details are sacrificed during CG processes,this method exhibits remarkable computational efficiency.In this study,a comprehensive CG model for polystyrene-block-poly(2-vinylpyridine),PS-b-P2VP,one of the most extensively studied BCPs for its high Flory-Huggins interaction parameter,is constructed,with parameters optimized using target values derived from all-atom MD simulations.The CG model precisely coincides with various classical self-assembling morphologies observed in experimental studies,matching the theoretical phase diagrams.Moreover,the conformational asymmetry of the experimental phase diagram is also clearly revealed by our simulation results,and the phase boundaries obtained from simulations are highly consistent with experimental results.The CG model is expected to extend to simulate the self-assembly behaviors of other BCPs in addition to PS-b-P2VP,thus increasing understanding of the microphase separation of BCPs from the molecular level.展开更多
基金supported by the National Natural Science Foundation of China (Nos.22208218,22078196,and 22278268)the Natural Science Foundation of Shanghai (No.22ZR1460400)Collaborative Innovation Center of Fragrance Flavour and Cosmetics,and Collaborative Innovation Project of Shanghai Institute of Technology (No.XTCX2023-07)。
文摘The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.
基金supported by the Major Research Instrument Development Project of the National Natural Science Foundation of China(32527801)the National Natural Science Foundation of China(32301168)+1 种基金the Ningbo Natural Science Foundation of China(2023J351)the Yongjiang Innovative Talents Project of Ningbo City(2024A-172-G).
文摘Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.
基金supported by the National Key Research and Development Program of China (Nos. 2022YFB3605203 and 2022YFB3608100)the National Natural Science Foundation of China (Nos. 62321004, 62227817, and 62374001)。
文摘The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off(LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of(002) and(102) planes, alongside a low dislocation density of 1.6 × 10^(6) cm^(-2). This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61521064,61522408,61574169,61334007,61474136,and 61574166)the Ministry of Science and Technology of China(Grant Nos.2018YFB0406504,2016YFA0201803,2016YFA0203800,and 2017YFB0405603)+1 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Grant Nos.QYZDB-SSW-JSC048 and QYZDY-SSW-JSC001)the Beijing Municipal Science and Technology Project,China(Grant No.Z171100002017011)
文摘Ultraviolet(UV) photodetectors(PDs) have drawn great attention in recent years due to their potential application in civil and military fields. Because of its ultrawide bandgap, low cost, strong radiation hardness, and high thermal and chemical stability with high visible-light transparency, Ga_2O_3 is regarded as the most promising candidate for UV detection.Furthermore, the bandgap of Ga_2O_3 is as high as 4.7–4.9 eV, directly corresponding to the solar-blind UV detection band with wavelength less than 280 nm. There is no need of doping in Ga_2O_3 to tune its bandgap, compared to AlGaN, MgZnO,etc, thereby avoiding alloy composition fluctuations and phase separation. At present, solar-blind Ga_2O_3 photodetectors based on single crystal or amorphous Ga_2O_3 are mainly focused on metal–semiconductor–metal and Schottky photodiodes.In this work, the recent achievements of Ga_2O_3 photodetectors are systematically reviewed. The characteristics and performances of different photodetector structures based on single crystal Ga_2O_3 and amorphous Ga_2O_3 thin film are analyzed and compared. Finally, the prospects of Ga_2O_3 UV photodetectors are forecast.
基金supported by the National Key R&D Program of China (Nos.2017YFA0402500 and 2017YFE0301802)National Natural Science Foundation (No.11475172)the Key Research Program of Frontier Sciences, CAS (No.QYZDJ-SSW-DQC010)
文摘A series of experimental results of field-reversed configurations(FRCs) on a KMAX(Keda Mirror with AXisymmetricity) tandem mirror machine are reported.Single-side FRC translation processes with three different gas species were measured by avalanche photodiodes.Consistent with the theoretical prediction, the measured FRC speeds were inversely proportional to the square root of the ion mass.However, the speeds of the hydrogen FRC increased even in a uniform magnetic field region while the speeds of the helium and argon FRCs decreased.Possible mechanisms are discussed.The speed of the second pass due to the reflection of the mirror fields was found to be ~1/3 of the first pass speed.The internal magnetic fields were measured for a colliding-merging argon FRC, and the results show that, even for very slowmoving FRCs, merging can occur.
基金supported by the Youth Innovation Promotion Association CAS(No.2016238)the National Natural Science Foundation of China(No.11305246)
文摘Large accelerator facilities require clocks and triggers with high accuracy to synchronize equipment and devices. A new femtosecond timing system was designed to meet the demands of new facilities. In this system, the radio-frequency signal is modulated in a continuous-wave laser carrier with frequency stabilization, and timing events are distributed in the same fiber. The phase drift is detected precisely, based on the principle of the Michelson interferometer. The phase drift is compensated with coarse and fine correctors afterward. We aim to realize the stable transmission of the RF signal and timing events for a long distance and duration, with the phase drift and additive jitter in femtoseconds. After the extension, the system will become a complete solution for the clock-and-trigger distribution of synchrotron radiation facilities, free-electron lasers, and other accelerators. The physics design, simulation analysis, and preliminary results are included in the paper.
基金Supported by the Key Research&Development Program of Shaanxi Province(No.2022SF-311,No.2024SFYBXM-328,No.2024SF-YBXM-325)the Natural Science Basic Research Program of Shaanxi Province,China(No.2021JQ-385).
文摘AIM:To evaluate the effect of bone morphogenetic protein-6(BMP-6)on transforming growth factor(TGF)-β_(2)-induced epithelial-mesenchymal transition(EMT)in retinal pigment epithelium(RPE).METHODS:Adult retinal pigment epithelial cell line(ARPE-19)were randomly divided into control,TGF-β_(2)(5μg/L),and BMP-6 small interfering RNA(siRNA)group.The cell morphology was observed by microscopy,and the cell migration ability were detected by Transwell chamber.The EMT-related indexes and BMP-6 protein levels were detected by Western blotting.Furthermore,a BMP-6 overexpression plasmid was constructed and RPE cells were divided into the control group,TGF-β_(2)+empty plasmid group,BMP-6 overexpression group,and TGF-β_(2)+BMP-6 overexpression group.The EMT-related indexes and extracellular regulated protein kinases(ERK)protein levels were detected.RESULTS:Compared with the control group,the migration of RPE cells in the TGF-β_(2) group was significantly enhanced.TGF-β_(2) increased the protein expression levels ofα-smooth muscle actin(α-SMA),fibronectin and vimentin but significantly decreased the protein levels of E-cadherin and BMP-6(P<0.05)in RPE.Similarly,the migration of RPE cells in the BMP-6 siRNA group was also significantly enhanced.BMP-6 siRNA increased the protein expression levels ofα-SMA,fibronectin and vimentin but significantly decreased the protein expression levels of E-cadherin(P<0.05).Overexpression of BMP-6 inhibited the migration of RPE cells induced by TGF-β_(2) and prevented TGF-β_(2) from affecting EMT-related biomarkers(P<0.05).CONCLUSION:BMP-6 prevents the EMT in RPE cells induced by TGF-β_(2),which may provide a theoretical basis for the prevention and treatment of proliferative vitreoretinopathy.
基金funded by the National Key R&D Program of China(No.2020YFC150071)partly supported by the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)and the Research Funds for the Interdisciplinary Projects,CHU(No.300104240914)。
文摘0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.
基金supported by the Key Research and Development Program in Shaanxi Province,China(No.2022ZDLSF07-05)the Fundamental Research Funds for the Central Universities,CHD(No.300102352901)。
文摘Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research problem.Previous studies relied on statistical regression models that failed to capture the complex nonlinear relationships between carbon emissions and characteristic variables.In this study,we propose a machine learning algorithm for carbon emissions,a Bayesian optimized XGboost regression model,using multi-year energy carbon emission data and nighttime lights(NTL)remote sensing data from Shaanxi Province,China.Our results demonstrate that the XGboost algorithm outperforms linear regression and four other machine learning models,with an R^(2)of 0.906 and RMSE of 5.687.We observe an annual increase in carbon emissions,with high-emission counties primarily concentrated in northern and central Shaanxi Province,displaying a shift from discrete,sporadic points to contiguous,extended spatial distribution.Spatial autocorrelation clustering reveals predominantly high-high and low-low clustering patterns,with economically developed counties showing high-emission clustering and economically relatively backward counties displaying low-emission clustering.Our findings show that the use of NTL data and the XGboost algorithm can estimate and predict carbon emissionsmore accurately and provide a complementary reference for satellite remote sensing image data to serve carbon emission monitoring and assessment.This research provides an important theoretical basis for formulating practical carbon emission reduction policies and contributes to the development of techniques for accurate carbon emission estimation using remote sensing data.
文摘Objective This systematic review aimed to identify the predictors of recovery from dysphagia after stroke in the last ten years,thereby providing an evidence-based basis for nurses to identify high-risk patients and develop individualized rehabilitation plans to improve patient prognosis.Methods Databases including the China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBMdisc),China Science and Technology Journal(VIP),WanFang,PubMed,Embase,CINAHL,Web of Science,the Cochrane Library,and Scopus were retrieved to search for literature on the predictors of recovery from dysphagia after stroke.The retrieval period was from January 2013 to December 2023.The quality of studies was assessed using the Newcastle-Ottawa Scale(NOS)and the Prediction model Risk of Bias Assessment Tool(PROBAST).Meta-analysis was performed using Revman5.3 and Stata15.1 software.The review protocol has been registered with PROSPERO(CRD42024605570).Results A total of 1,216 results were obtained,including 599 in English and 617 in Chinese.A total of 34 studies were included,involving 156,309 patients with post-stroke dysphagia,and the rate of dysphagia recovery increased from 13.53%at 1 week to 95%at 6 months after stroke.Meta-analysis results showed that older age[OR=1.06,95%CI(1.04,1.08),P<0.001],lower BMI[OR=1.28,95%CI(1.17,1.40),P<0.001],bilateral stroke[OR=3.10,95%CI(2.04,4.72),P<0.001],higher National Institutes of Health Stroke Scale(NIHSS)score[OR=1.19,95%CI(1.01,1.39),P=0.030],tracheal intubation[OR=5.08,95%CI(1.57,16.39),P=0.007]and aspiration[OR=4.70,95%CI(3.06,7.20),P<0.001]were unfavorable factors for the recovery of swallowing function in patients with post-stroke dysphagia.Conclusions The lack of standardized criteria for rehabilitation assessment of post-stroke dysphagia has resulted in reported recovery rates of swallowing function exhibiting wide variability.Nurses should take targeted preventive measures for patients aged≥70 years,low BMI,bilateral stroke,high NIHSS score,tracheal intubation,and aspiration to promote the recovery of swallowing function in patients with post-stroke dysphagia.
基金supported by National Science Fund for Distinguished Young Scholars(Grant No.52325206)National Key Research and Development Program of China(Grant No.2021YFF0500600)+3 种基金National Natural Science Foundation of China(Grant Nos.U2001220 and 52203298)Shenzhen Technical Plan Project(Grant Nos.RCJC20200714114436091,JCYJ20220530143012027,JCYJ20220818101003008,and JCYJ20220818101003007)Tsinghua Shenzhen International Graduate School-Shenzhen Pengrui Young Faculty Program of Shenzhen Pengrui Foundation(Grant No.SZPR2023006)Shenzhen Science and Technology Program(Grant No.WDZC20231126160733001).
文摘Composite solid electrolytes(CSEs)are considered among the most promising candidates for solid-state batteries.However,their practical application is hindered by low ionic conductivity and a limited lithium-ion transference number,primarily owing to the insufficient mobility of Li+.In this work,we design a heterojunc-tion nanoparticle composed of bimetallic zeolitic imidazolate frameworks(ZIFs)coupled with amorphous tita-nium oxide(TiO_(2)@Zn/Co–ZIF)as a filler to fabricate a composite solid-state electrolyte(PVZT).The amor-phous TiO_(2) coating facilitates salt dissociation through Lewis acid–base interactions with the anions of the lithium salt.Meanwhile,the Zn/Co–ZIF framework not only provides additional selective pathways for Li+transport but also effectively restricts anion migration through its confined pore size.The synergistic effect results in a high room-temperature ionic conductivity(8.8×10^(-4) S·cm^(-1))and a lithium-ion transference number of 0.47 for PVZT.A symmetrical cell using PVZT demonstrates stable Li+deposition/stripping for over 1100 h at a current density of 0.1 mA·cm^(-2).Additionally,a LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li full cell using PVZT retains 75.0%of its capacity after 1200 cycles at a 2 C rate.This work offers valuable insights into the design of func-tional fillers for CSEs with highly efficient ion transport.
基金the National Natural Science Foundation of China,Grant/Award Number:32000358the CAMS initiative for Innovative Medicine of China,Grant/Award Number:2021-I2M-1-035Young Elite Scientists Sponsorship Program by CAST(YESS),Grant/Award Number:2020QNRC001。
文摘Background:The aim was to elucidate the function of IL-37 in middle east respiratory syndrome coronavirus(MERS-CoV)infection,thereby providing a novel therapeutic strategy for managing the clinical treatment of inflammatory response caused by respiratory virus infection.Methods:We investigated the development of MERS by infecting hDPP4 mice with hCoV-EMC(107 TCID50[50%tissue culture infectious dose])intranasally.We infected A549 cells with MERS-CoV,which concurrently interfered with IL-37,detecting the viral titer,viral load,and cytokine expression at certain points postinfection.Meanwhile,we administered IL-37(12.5μg/kg)intravenously to hDPP4 mice 2 h after MERS-CoV-2 infection and collected the serum and lungs 5 days after infection to investigate the efficacy of IL-37 in MERS-CoV infection.Results:The viral titer of MERS-CoV-infected A549 cells interfering with IL-37 was significantly reduced by 4.7-fold,and the viral load of MERS-CoV-infected hDPP4 mice was decreased by 59-fold in lung tissue.Furthermore,the administration of IL-37 suppressed inflammatory cytokine and chemokine(monocyte chemoattractant protein 1,interferon-γ,and IL-17A)expression and ameliorated the infiltration of inflammatory cells in hDPP4 mice.Conclusion:IL-37 exhibits protective properties in severe pneumonia induced by MERS-CoV infection.This effect is achieved through attenuation of lung viral load,suppression of inflammatory cytokine secretion,reduction in inflammatory cell infiltration,and mitigation of pulmonary injury.
文摘目的:探讨保留肝实质的治疗方式在结直肠癌肝转移(colorectal liver metastases,CRLM)手术切除中的意义。方法:回顾性分析北京大学肿瘤医院2000年1月至2016年5月手术切除的CRLM患者377例,根据手术方式分为保留肝实质(parenchymalsparing hepatectomy,PSH)组305例和大范围肝切除(major hepatectomy,MH)组72例。比较两组患者的临床特征、手术情况、术后并发症及预后。结果:PSH组肝转移灶个数少于MH组,差异比较具有统计学意义(P=0.000)。全组采用PSH治疗的患者占80.9%,且随时间增长逐渐增多。PSH组手术时间比MH组短(177.5 min vs.220 min,P=0.000),手术出血比MH组少(150 m L vs.300 m L,P=0.000),术后并发症发生率比MH组低(47.4%vs.64.8%,P=0.008)。PSH组与MH组患者的总生存(overall survival,OS)时间、肝内无复发生存(hepatic recurrence free survival,HFRS)时间差异无统计学意义。PSH组患者复发后接受局部治疗的比例明显增加(42.8%vs.25.6%,P=0.040),复发患者中接受局部治疗的患者生存期明显延长(58个月vs.24个月,P=0.000)。结论:CRLM患者手术时采用PSH的治疗方式肝内复发率更低,安全性更高,复发后再次接受局部治疗的可能性明显增加,是推荐的治疗模式。
基金Supported by Daqing City Philosophy and Social Sciences Planning Research Project(DSGB 2025011)the Heilongjiang Province Education Science Planning Key Project(GJB1320229).
文摘Based on questionnaire surveys and field interviews conducted with various types of agricultural production organizations across five districts and four counties in Daqing City,this study combines relevant theoretical frameworks to systematically examine the evolution,performance,and influencing factors of governance mechanisms within these organizations.Using both quantitative and inductive analytical methods,the paper proposes innovative designs and supporting measures for improving governance mechanisms.The findings reveal that,amid large-scale farmland circulation,the governance mechanisms of agricultural production organizations in Daqing City are evolving from traditional to modern structures.However,challenges remain in areas such as decision-making efficiency,benefit distribution,and supervision mechanisms.In response,this study proposes innovative governance designs focusing on decision-making processes,profit-sharing mechanisms,and risk prevention.Corresponding policy recommendations are also provided to support the sustainable development of agricultural modernization in China.
基金supported by the National Natural Science Foundation of China(22438005,22108117).
文摘Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)molecular dynamics(MD)simulation offers a microscopic angle to view the self-assembly of BCPs.Although some molecular details are sacrificed during CG processes,this method exhibits remarkable computational efficiency.In this study,a comprehensive CG model for polystyrene-block-poly(2-vinylpyridine),PS-b-P2VP,one of the most extensively studied BCPs for its high Flory-Huggins interaction parameter,is constructed,with parameters optimized using target values derived from all-atom MD simulations.The CG model precisely coincides with various classical self-assembling morphologies observed in experimental studies,matching the theoretical phase diagrams.Moreover,the conformational asymmetry of the experimental phase diagram is also clearly revealed by our simulation results,and the phase boundaries obtained from simulations are highly consistent with experimental results.The CG model is expected to extend to simulate the self-assembly behaviors of other BCPs in addition to PS-b-P2VP,thus increasing understanding of the microphase separation of BCPs from the molecular level.
