A fully digital data acquisition system based on a field-programmable gate array(FPGA) was developed for a CsI(Tl) array at the external target facility(ETF) in the Heavy Ion Research Facility in Lanzhou(HIRFL). To pr...A fully digital data acquisition system based on a field-programmable gate array(FPGA) was developed for a CsI(Tl) array at the external target facility(ETF) in the Heavy Ion Research Facility in Lanzhou(HIRFL). To process the CsI(Tl) signals generated by γ-rays and light-charged ions, a scheme for digital pulse processing algorithms is proposed. Every step in the algorithms was benchmarked using standard γ and α sources. The scheme, which included a moving average filter, baseline restoration, leading-edge discrimination, moving window deconvolution, and digital charge comparison, was subsequently implemented on the FPGA. A good energy resolution of 5.7% for 1.33-MeV γ-rays and excellent α-γ identification using the digital charge comparison method were achieved, which satisfies CsI(Tl) array performance requirements.展开更多
Autophagy is crucial for maintaining cellular homeostasis,and can be activated after ischemic stroke.It also participates in nerve injury and repair.The purpose of this study was to investigate whether an enriched env...Autophagy is crucial for maintaining cellular homeostasis,and can be activated after ischemic stroke.It also participates in nerve injury and repair.The purpose of this study was to investigate whether an enriched environment has neuroprotective effects through affecting autophagy.A Sprague-Dawley rat model of transient ischemic stroke was prepared by occlusion of the middle cerebral artery followed by reperfusion.One week after surgery,these rats were raised in either a standard environment or an enriched environment for 4 successive weeks.The enriched environment increased Beclin-1 expression and the LC3-II/LC3-I ratio in the autophagy/lysosomal pathway in the penumbra of middle cerebral artery-occluded rats.Enriched environment-induced elevations in autophagic activity were mainly observed in neurons.Enriched environment treatment also promoted the fusion of autophagosomes with lysosomes,enhanced the lysosomal activities of lysosomal-associated membrane protein 1,cathepsin B,and cathepsin D,and reduced the expression of ubiquitin and p62.After 4 weeks of enriched environment treatment,neurological deficits and neuronal death caused by middle cerebral artery occlusion/reperfusion were significantly alleviated,and infarct volume was significantly reduced.These findings suggest that neuronal autophagy is likely the neuroprotective mechanism by which an enriched environment promotes recovery from ischemic stroke.This study was approved by the Animal Ethics Committee of the Kunming University of Science and Technology,China(approval No.5301002013855)on March 1,2019.展开更多
China plans to develop the next generation dark matter particle explorer satellite,referred to as the Very Large Area Space Telescope(VLAST).As an essential step in this process,the prototype design of detectors and e...China plans to develop the next generation dark matter particle explorer satellite,referred to as the Very Large Area Space Telescope(VLAST).As an essential step in this process,the prototype design of detectors and electronics for the VLAST is currently underway.The nuclide detector is a core detector in the VLAST.It mainly measures nuclides’charges and distinguishes high-energy gamma rays and electrons.This paper will discuss the prototype readout electronics for the VLAST’s nuclide detector,which accurately measures the charge signal of the photomultiplier tubes using the VATA160 applicationspecific integrated circuit chip;furthermore,we consider a series of critical problems,including radiation-hardening and environment monitoring.The test results show that the system exhibits stable operation,good performance,and good technical indicators.Furthermore,each electronic channel achieves a dynamic range of 0-12.5 pC,the random noise level exceeds 1.6 fC,and the integral nonlinearity exceeds 0.35%.展开更多
Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been devel...Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.展开更多
With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM...With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM)) is investigated over a temperature range from-40 to 40 ℃. With the increase in temperature, the output signal increases by ～ 24% with CsI:Tl(PD) and decreases by ～69% with CsI:Tl(SiPM). To reduce the effect of temperature in outer space, a method of bias voltage compensation is adopted for CsI:Tl(SiPM). Our study demonstrates that after correcting the temperature the variation in the analog-to-digital converter's amplitude is< 3%.展开更多
AIM:To investigate the changes of retinal nerve fiber layer(RNFL)among normal individuals,diabetic patients without diabetic retinopathy(NDR)and non-proliferative diabetic retinopathy(NPDR),and explore the possible ri...AIM:To investigate the changes of retinal nerve fiber layer(RNFL)among normal individuals,diabetic patients without diabetic retinopathy(NDR)and non-proliferative diabetic retinopathy(NPDR),and explore the possible risk factors of early diabetic retinopathy(DR).METHODS:In this cross-sectional study,107 participants were divided in three groups.Totally 31 normal individuals(control group),40 diabetic patients without DR(NDR group)and 36 patients with NPDR(NPDR group)were included.Optical coherence tomography(OCT)was used to detect RNFL thickness and other optic disc parameters among different groups.The potential association between RNFL loss and systemic risk factors were assessed for DR,including diabetes duration,body mass index(BMI),hemoglobin A1 c(Hb A1 c),serum lipids,and blood pressure.RESULTS:The average and each quadrant RNFL thickness were thinner in NPDR group compared to control group of the right(P=0.00,P=0.01,P=0.01,P=0.02,P=0.04)and left eyes(P=0.00,P=0.00,P=0.00,P=0.03,P=0.04).The average,superior and inferior RNFL thickness were thinner in NDR group compared to the NPDR group of the right(P=0.00,P=0.02,P=0.03)and left eyes(P=0.00,P=0.00,P=0.01).Diabetic duration was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.385,P=0.001;r=-0.366,P=0.001;r=-0.503,P=0.000)and left eyes(r=-0.271,P=0.018;r=0.278,P=0.015;r=-0.260,P=0.023).Hb A1 c was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.316 P=0.005;r=-0.414,P=0.000;r=-0.418,P=0.000)and left eyes(r=-0.367,P=0.001;r=-0.250,P=0.030;r=-0.393,P=0.000).Systolic pressure was negatively correlated with the inferior and average RNFL thickness of the right eye(r=-0.402,P=0.000;r=-0.371,P=0.001)and was negatively correlated with the superior and average RNFL thickness of the left eye(r=-0.264,P=0.021;r=-0.233,P=0.043).CONCLUSION:RNFL loss,especially in the superior and inferior quadrants,may be the earliest structural change of the retina in diabetic patients,and is also associated with diabetic duration,Hb A1 c,and systolic pressure.展开更多
Background:Transarterial chemoembolization(TACE)and percutaneous microwave coagulation therapy(PMCT)are commonly used to treat intrahepatic recurrent liver cancers.However,there is no informa-tion regarding their effe...Background:Transarterial chemoembolization(TACE)and percutaneous microwave coagulation therapy(PMCT)are commonly used to treat intrahepatic recurrent liver cancers.However,there is no informa-tion regarding their effectiveness in patients with recurrent intrahepatic cholangiocarcinoma(ICC)after resection.Methods:A total of 275 patients with localized recurrent ICC who received either TACE(n=183)or PMCT(n=92)were studied.A propensity score matching analysis was performed to compare prognostic impact of TACE and PMCT.Prognostic factors for TACE and PMCT were identified respectively.Predictive nomograms for each TACE and PMCT were developed using the Cox independent prognostic factors and were validated in independent patient groups by receiver operating characteristic curves and area under curve values.Results:Both TACE and PMCT provided curativeness in partial patients(5-year overall survival:21.4%and 6.1%,respectively),but TACE provided better survival benefit in both overall patients(hazard ratio[HR]=0.71;95%confidence interval[CI]:0.50–0.97;P=0.034)and propensity score matching analysis(HR=0.69;95%CI:0.47–0.98;P=0.041).Independent prognostic factors for TACE were tumor size>5 cm,poor differentiation,and major resection,whereas poor differentiation,hepatitis B virus infection,cholelithiasis,and lymph node metastasis were identified for PMCT.Both predictive nomograms for TACE and PMCT were validated to be effective with area under curve values of 0.77 and 0.70,respectively.Conclusions:TACE provided better survival benefits compared to PMCT.However,there was a disparity in prognostic factors,suggesting evaluation of the two nomograms may be supportive in modality selection.Further prospective validation studies are required for the results to be applied in clinical medicine.展开更多
BACKGROUND： Early diagnosis of gallbladder cancer（GBC） can remarkably improve the prognosis of patients. This study aimed to develop a nomogram for individualized diagnosis of stage Ⅰ-Ⅱ GBC in chronic cholecystit...BACKGROUND： Early diagnosis of gallbladder cancer（GBC） can remarkably improve the prognosis of patients. This study aimed to develop a nomogram for individualized diagnosis of stage Ⅰ-Ⅱ GBC in chronic cholecystitis patients with gallbladder wall thickening.METHODS： The nomogram was developed using logistic regression analyses based on a retrospective cohort consisting of 89 consecutive patients with stage Ⅰ-Ⅱ GBC and 1240 patients with gallbladder wall thickening treated at one biliary surgery center in Shanghai between January 2009 and December 2011. The accuracy of the nomogram was validated by discrimination, calibration and a prospective cohort treated at another center between January 2012 and December 2014（n=928）.RESULTS： Factors included in the nomogram were advanced age, hazardous alcohol consumption, long-standing diagnosed gallstones, atrophic gallbladder, gallbladder wall calcification, intraluminal polypoid lesion, higher wall thickness ratio and mucosal line disruption. The nomogram had concordance indices of 0.889 and 0.856 for the two cohorts, respectively. Internal and external calibration curves fitted well. The area under the receiver-operating characteristic curves of the nomogram was higher than that of multidetector row computed tomography in diagnosis of stage Ⅰ-Ⅱ GBC（P〈0.001）.CONCLUSION： The proposed nomogram improves individualized diagnosis of stage Ⅰ-Ⅱ GBC in chronic cholecystitis patients with gallbladder wall thickening, especially for those the imaging features alone do not allow to confirm the diagnosis.展开更多
Cholangiocarcinoma refers to malignant tumors that develop in epithelial lining of biliary system, and it is divided into two categories according to tumor location, intrahepatic cholangiocarcinoma （ICC） and extrahe...Cholangiocarcinoma refers to malignant tumors that develop in epithelial lining of biliary system, and it is divided into two categories according to tumor location, intrahepatic cholangiocarcinoma （ICC） and extrahepatic cholangiocarcinoma （ECC）. ICC occurs from the epithelial cells of the intrahepatic bile duct, its branches and interlobular biliary tree; and ECC is divided into hilar cholangiocarcinoma and distal cholangiocarcinoma by the circumscription at the confluence of cystic duct and the common hepatic duct.展开更多
The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge...The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge identification potential of PSD and to enhance its capability to identify gamma ray events, we develop an alignment method for the PSD. The path length of a given track in the volume of a PSD bar is derived taking into account the shift and rotation alignment corrections. By examining energy spectra of corner-passing events and fully contained events, position shifts and rotations of all PSD bars are obtained, and are found to be on average about 1 mm and 0.0015 radian respectively. To validate the alignment method, we introduce artificial shifts and rotations of PSD bars into the detector simulation.These shift and rotation parameters can be recovered successfully by the alignment procedure. As a result of the PSD alignment procedure, the charge resolution of the PSD is improved from 4% to 8%, depending on the nuclei.展开更多
The DArk Matter Particle Explorer(DAMPE)is a satellite-borne detector for high-energy cosmic rays and y-rays.To fully understand the detector performance and obtain reliable physical results,extensive simulations of t...The DArk Matter Particle Explorer(DAMPE)is a satellite-borne detector for high-energy cosmic rays and y-rays.To fully understand the detector performance and obtain reliable physical results,extensive simulations of the detector are necessary.The simulations are particularly important for the data analysis of cosmic ray nuclei,which relies closely on the hadronic and nuclear interactions of particles in the detector material.Widely adopted simulation softwares include the GEANT4 and FLUKA,both of which have been implemented for the DAMPE simulation tool.Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares.Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis.展开更多
The DArk Matter Particle Explorer(DAMPE) is a space-borne apparatus for detecting the highenergy cosmic-ray-like electrons, γ-rays, protons and heavy ions. The Plastic Scintillator Detector(PSD)is the top-most sub-de...The DArk Matter Particle Explorer(DAMPE) is a space-borne apparatus for detecting the highenergy cosmic-ray-like electrons, γ-rays, protons and heavy ions. The Plastic Scintillator Detector(PSD)is the top-most sub-detector of the DAMPE. The PSD is designed to measure the charge of incident highenergy particles and it also serves as a veto detector for discriminating γ-rays from charged particles. In this paper, a PSD on-orbit calibration procedure is described, which includes the five steps of pedestal, dynode correlation, response to minimum-ionizing particles, light attenuation function and energy reconstruction.A method for reconstructing the charge of incident high energy cosmic-ray particles is introduced. The detection efficiency of each PSD strip is verified to be above 99.5%; the total efficiency of the PSD for charged particles is above 99.99%.展开更多
POLAR is a compact space-borne detector initially designed to measure the polarization of hard X-rays emitted from Gamma-Ray Bursts in the energy range 50–500 ke V.This instrument was launched successfully onboard th...POLAR is a compact space-borne detector initially designed to measure the polarization of hard X-rays emitted from Gamma-Ray Bursts in the energy range 50–500 ke V.This instrument was launched successfully onboard the Chinese space laboratory Tiangong-2(TG-2) on 2016 September 15.After being switched on a few days later,tens of gigabytes of raw detection data were produced in-orbit by POLAR and transferred to the ground every day.Before the launch date,a full pipeline and related software were designed and developed for the purpose of quickly pre-processing all the raw data from POLAR,which include both science data and engineering data,then to generate the high level scientific data products that are suitable for later science analysis.This pipeline has been successfully applied for use by the POLAR Science Data Center in the Institute of High Energy Physics(IHEP) after POLAR was launched and switched on.A detailed introduction to the pipeline and some of the core relevant algorithms are presented in this paper.展开更多
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be class...We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.展开更多
Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts（GRBs） and electromagnetic（EM） counterparts of gravitational waves（GWs）. Based on n...Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts（GRBs） and electromagnetic（EM） counterparts of gravitational waves（GWs）. Based on near real-time Fermi/GBM data, we developed a low-latency pipeline to automatically calculate the temporal and spectral properties of GRBs. With this pipeline, some important parameters can be obtained, such as T_（90） and fluence, within ～ 20 min after the GRB trigger.For ～ 90% of GRBs, T90 and fluence are consistent with the GBM catalog results within 2σ errors.This pipeline has been used by the Gamma-ray Bursts Polarimeter（POLAR） and the Insight Hard Xray Modulation Telescope（Insight-HXMT） to follow up the bursts of interest. For GRB 170817 A, the first EM counterpart of GW events detected by Fermi/GBM and INTEGRAL/SPI-ACS, the pipeline gave T90 and spectral information 21 min after the GBM trigger, providing important information for POLAR and Insight-HXMT observations.展开更多
The patient was a 63-year-old female,who was diagnosed with advanced pancreatic cancer with mediastinal lymph node and lung metastases and pleural effusion in June 2019.First-line treatment with 6 cycles of gemcitabin...The patient was a 63-year-old female,who was diagnosed with advanced pancreatic cancer with mediastinal lymph node and lung metastases and pleural effusion in June 2019.First-line treatment with 6 cycles of gemcitabine plus tegafur with best response of partial response.Second-line treatment was 4 cycles of nab-paclitaxel monotherapy ended up with disease progression.Third-line treatment was sintilimab with anlotinib for 10 cycles.The patient's condition has achieved clinical complete remission so far.展开更多
The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,...The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.展开更多
The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the ...The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.展开更多
Objective: To explore the feasibility of the submental island flap in the repair of hypopharyngeal defects.Methods: We collected wet specimens of fresh cadaveric heads from the Han Chinese adult population for applied...Objective: To explore the feasibility of the submental island flap in the repair of hypopharyngeal defects.Methods: We collected wet specimens of fresh cadaveric heads from the Han Chinese adult population for applied anatomy of the submental island flap, and followed five patients with pyriform sinus carcinoma after reconstruction surgery using submental island flaps.Results: We found that the average length and width of the submental island flaps were (65.20 ± 11.69) mm and (46.70 ± 6.59) mm, respectively.The skin flap in all five patients survived after surgery, and tracheal tubes and gastric tubes were removed 7-36 days after surgery.Patients were followed up for 24-42 months, pharyngeal flaps grew well, and speech and swallowing functions were satisfactory.Conclusion: The submental island flap is a preferred material for the repair of hypopharyngeal defects after hypopharyngeal carcinoma resection, because of good blood supply, easy harvesting, and high survival rate.展开更多
Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Prev...Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.展开更多
基金supported by the Open Research Project of CAS Large Research InfrastructuresCAS Key Technology Talent ProgramNational Natural Science Foundations of China (Nos.U2031206 and 12273086)
文摘A fully digital data acquisition system based on a field-programmable gate array(FPGA) was developed for a CsI(Tl) array at the external target facility(ETF) in the Heavy Ion Research Facility in Lanzhou(HIRFL). To process the CsI(Tl) signals generated by γ-rays and light-charged ions, a scheme for digital pulse processing algorithms is proposed. Every step in the algorithms was benchmarked using standard γ and α sources. The scheme, which included a moving average filter, baseline restoration, leading-edge discrimination, moving window deconvolution, and digital charge comparison, was subsequently implemented on the FPGA. A good energy resolution of 5.7% for 1.33-MeV γ-rays and excellent α-γ identification using the digital charge comparison method were achieved, which satisfies CsI(Tl) array performance requirements.
基金This work was supported by the National Natural Science Foundation of China,Nos.81660383(to YHD),81860411(to HYH),81960418(to YHD)Yunnan Ten Thousand Talents Plan Young&Elite Talents Project of China,No.YNWR-QNBJ-2018-034(to YHD)+1 种基金Applied Basic Research Foundation of Yunnan Province of China,Nos.2017FB113(to YHD),2019FB098(to HYH)Science Research Fund of Yunnan Provincial Department of Education of China,No.2018JS016(to HYH).
文摘Autophagy is crucial for maintaining cellular homeostasis,and can be activated after ischemic stroke.It also participates in nerve injury and repair.The purpose of this study was to investigate whether an enriched environment has neuroprotective effects through affecting autophagy.A Sprague-Dawley rat model of transient ischemic stroke was prepared by occlusion of the middle cerebral artery followed by reperfusion.One week after surgery,these rats were raised in either a standard environment or an enriched environment for 4 successive weeks.The enriched environment increased Beclin-1 expression and the LC3-II/LC3-I ratio in the autophagy/lysosomal pathway in the penumbra of middle cerebral artery-occluded rats.Enriched environment-induced elevations in autophagic activity were mainly observed in neurons.Enriched environment treatment also promoted the fusion of autophagosomes with lysosomes,enhanced the lysosomal activities of lysosomal-associated membrane protein 1,cathepsin B,and cathepsin D,and reduced the expression of ubiquitin and p62.After 4 weeks of enriched environment treatment,neurological deficits and neuronal death caused by middle cerebral artery occlusion/reperfusion were significantly alleviated,and infarct volume was significantly reduced.These findings suggest that neuronal autophagy is likely the neuroprotective mechanism by which an enriched environment promotes recovery from ischemic stroke.This study was approved by the Animal Ethics Committee of the Kunming University of Science and Technology,China(approval No.5301002013855)on March 1,2019.
基金supported by the National Natural Science Foundation of China(Nos.U2031206,U1831206,11975292,11875304)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.GJJSTD20210009)+1 种基金the CAS“Light of West China”Programthe CAS Pioneer Hundred Talent Program。
文摘China plans to develop the next generation dark matter particle explorer satellite,referred to as the Very Large Area Space Telescope(VLAST).As an essential step in this process,the prototype design of detectors and electronics for the VLAST is currently underway.The nuclide detector is a core detector in the VLAST.It mainly measures nuclides’charges and distinguishes high-energy gamma rays and electrons.This paper will discuss the prototype readout electronics for the VLAST’s nuclide detector,which accurately measures the charge signal of the photomultiplier tubes using the VATA160 applicationspecific integrated circuit chip;furthermore,we consider a series of critical problems,including radiation-hardening and environment monitoring.The test results show that the system exhibits stable operation,good performance,and good technical indicators.Furthermore,each electronic channel achieves a dynamic range of 0-12.5 pC,the random noise level exceeds 1.6 fC,and the integral nonlinearity exceeds 0.35%.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Science(No.XDA04040202-3)
文摘Performance characterization for massive photomultiplier tubes(PMTs) is a frequently encountered procedure in large nuclear and particle experiments.To facilitate this work,a dedicated test bench system has been developed at the Institute of Modern Physics,Chinese Academy of Sciences.The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench,and up to 25 PMTs,with the diameter smaller than 2",can be tested simultaneously.The parameters of the light source pulses can be adjusted in a wide range,thus making it suitable for various characteristics measurements.The test bench system is highly automated with all the controlling operations integrated into a single software.Additionally,the hardware platform is extensible which allows complex testing schemes,and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient.All these features make the test bench versatile and reusable in different experiments.It has been first used in the construction of the Plastic Scintillator Detector(PSD) of DArk Matter Particle Explorer(DAMPE),and a total of 570 Hamamatsu R4443 tubes were tested successfully.The performance was verified and the testing results are also reported in this article.
基金supported by the National Natural Science Foundation of China(Nos.11575257,11575269,and U1732134)the Youth Innovation Promotion Association of the Chinese Academy of Science(No.2015342)
文摘With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal(CsI:Tl) detector readout with a PIN photodiode(CsI:Tl(PD)) and with a silicon photomultiplier(CsI:Tl(SiPM)) is investigated over a temperature range from-40 to 40 ℃. With the increase in temperature, the output signal increases by ～ 24% with CsI:Tl(PD) and decreases by ～69% with CsI:Tl(SiPM). To reduce the effect of temperature in outer space, a method of bias voltage compensation is adopted for CsI:Tl(SiPM). Our study demonstrates that after correcting the temperature the variation in the analog-to-digital converter's amplitude is< 3%.
基金Supported by National Natural Science Foundation of China(No.81472081)Natural Science Foundation of Jiangsu Province Project(No.BK2010539)2020 Qing Lan Project of Jiangsu Province。
文摘AIM:To investigate the changes of retinal nerve fiber layer(RNFL)among normal individuals,diabetic patients without diabetic retinopathy(NDR)and non-proliferative diabetic retinopathy(NPDR),and explore the possible risk factors of early diabetic retinopathy(DR).METHODS:In this cross-sectional study,107 participants were divided in three groups.Totally 31 normal individuals(control group),40 diabetic patients without DR(NDR group)and 36 patients with NPDR(NPDR group)were included.Optical coherence tomography(OCT)was used to detect RNFL thickness and other optic disc parameters among different groups.The potential association between RNFL loss and systemic risk factors were assessed for DR,including diabetes duration,body mass index(BMI),hemoglobin A1 c(Hb A1 c),serum lipids,and blood pressure.RESULTS:The average and each quadrant RNFL thickness were thinner in NPDR group compared to control group of the right(P=0.00,P=0.01,P=0.01,P=0.02,P=0.04)and left eyes(P=0.00,P=0.00,P=0.00,P=0.03,P=0.04).The average,superior and inferior RNFL thickness were thinner in NDR group compared to the NPDR group of the right(P=0.00,P=0.02,P=0.03)and left eyes(P=0.00,P=0.00,P=0.01).Diabetic duration was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.385,P=0.001;r=-0.366,P=0.001;r=-0.503,P=0.000)and left eyes(r=-0.271,P=0.018;r=0.278,P=0.015;r=-0.260,P=0.023).Hb A1 c was negatively correlated with the superior,inferior,and average RNFL thickness of the right(r=-0.316 P=0.005;r=-0.414,P=0.000;r=-0.418,P=0.000)and left eyes(r=-0.367,P=0.001;r=-0.250,P=0.030;r=-0.393,P=0.000).Systolic pressure was negatively correlated with the inferior and average RNFL thickness of the right eye(r=-0.402,P=0.000;r=-0.371,P=0.001)and was negatively correlated with the superior and average RNFL thickness of the left eye(r=-0.264,P=0.021;r=-0.233,P=0.043).CONCLUSION:RNFL loss,especially in the superior and inferior quadrants,may be the earliest structural change of the retina in diabetic patients,and is also associated with diabetic duration,Hb A1 c,and systolic pressure.
基金supported by grants from the National Natural Science Foundation of China(81902939)Startup Fund for Young Teacher from Shanghai Jiaotong University(KJ3-0214-18-0022).
文摘Background:Transarterial chemoembolization(TACE)and percutaneous microwave coagulation therapy(PMCT)are commonly used to treat intrahepatic recurrent liver cancers.However,there is no informa-tion regarding their effectiveness in patients with recurrent intrahepatic cholangiocarcinoma(ICC)after resection.Methods:A total of 275 patients with localized recurrent ICC who received either TACE(n=183)or PMCT(n=92)were studied.A propensity score matching analysis was performed to compare prognostic impact of TACE and PMCT.Prognostic factors for TACE and PMCT were identified respectively.Predictive nomograms for each TACE and PMCT were developed using the Cox independent prognostic factors and were validated in independent patient groups by receiver operating characteristic curves and area under curve values.Results:Both TACE and PMCT provided curativeness in partial patients(5-year overall survival:21.4%and 6.1%,respectively),but TACE provided better survival benefit in both overall patients(hazard ratio[HR]=0.71;95%confidence interval[CI]:0.50–0.97;P=0.034)and propensity score matching analysis(HR=0.69;95%CI:0.47–0.98;P=0.041).Independent prognostic factors for TACE were tumor size>5 cm,poor differentiation,and major resection,whereas poor differentiation,hepatitis B virus infection,cholelithiasis,and lymph node metastasis were identified for PMCT.Both predictive nomograms for TACE and PMCT were validated to be effective with area under curve values of 0.77 and 0.70,respectively.Conclusions:TACE provided better survival benefits compared to PMCT.However,there was a disparity in prognostic factors,suggesting evaluation of the two nomograms may be supportive in modality selection.Further prospective validation studies are required for the results to be applied in clinical medicine.
基金supported by grants from the National Natural Science Foundation of China(81401932,81272747 and 81372642)
文摘BACKGROUND： Early diagnosis of gallbladder cancer（GBC） can remarkably improve the prognosis of patients. This study aimed to develop a nomogram for individualized diagnosis of stage Ⅰ-Ⅱ GBC in chronic cholecystitis patients with gallbladder wall thickening.METHODS： The nomogram was developed using logistic regression analyses based on a retrospective cohort consisting of 89 consecutive patients with stage Ⅰ-Ⅱ GBC and 1240 patients with gallbladder wall thickening treated at one biliary surgery center in Shanghai between January 2009 and December 2011. The accuracy of the nomogram was validated by discrimination, calibration and a prospective cohort treated at another center between January 2012 and December 2014（n=928）.RESULTS： Factors included in the nomogram were advanced age, hazardous alcohol consumption, long-standing diagnosed gallstones, atrophic gallbladder, gallbladder wall calcification, intraluminal polypoid lesion, higher wall thickness ratio and mucosal line disruption. The nomogram had concordance indices of 0.889 and 0.856 for the two cohorts, respectively. Internal and external calibration curves fitted well. The area under the receiver-operating characteristic curves of the nomogram was higher than that of multidetector row computed tomography in diagnosis of stage Ⅰ-Ⅱ GBC（P〈0.001）.CONCLUSION： The proposed nomogram improves individualized diagnosis of stage Ⅰ-Ⅱ GBC in chronic cholecystitis patients with gallbladder wall thickening, especially for those the imaging features alone do not allow to confirm the diagnosis.
文摘Cholangiocarcinoma refers to malignant tumors that develop in epithelial lining of biliary system, and it is divided into two categories according to tumor location, intrahepatic cholangiocarcinoma （ICC） and extrahepatic cholangiocarcinoma （ECC）. ICC occurs from the epithelial cells of the intrahepatic bile duct, its branches and interlobular biliary tree; and ECC is divided into hilar cholangiocarcinoma and distal cholangiocarcinoma by the circumscription at the confluence of cystic duct and the common hepatic duct.
基金funded by the National Key Program for Research and Development (2016YFA0400200)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB23040000)the National Natural Science Foundation of China (Grant Nos. 11773086, U1738205, U1738127, 11673021, 11673047, 11673075, 11643011, 11773085, U1738207, U1738138, U1631111, U1738129 and 11703062)
文摘The Plastic Scintillator Detector(PSD) onboard the DArk Matter Particle Explorer(DAMPE)is designed to measure cosmic ray charge(Z) and to act as a veto detector for gamma ray identification.To fully exploit the charge identification potential of PSD and to enhance its capability to identify gamma ray events, we develop an alignment method for the PSD. The path length of a given track in the volume of a PSD bar is derived taking into account the shift and rotation alignment corrections. By examining energy spectra of corner-passing events and fully contained events, position shifts and rotations of all PSD bars are obtained, and are found to be on average about 1 mm and 0.0015 radian respectively. To validate the alignment method, we introduce artificial shifts and rotations of PSD bars into the detector simulation.These shift and rotation parameters can be recovered successfully by the alignment procedure. As a result of the PSD alignment procedure, the charge resolution of the PSD is improved from 4% to 8%, depending on the nuclei.
基金Supported by the National Key Research and Development Program of China(Grant No.2016YFA0400200)the National Natural Science Foundation of China(Grant Nos.11722328,11773085,U1738127,U1738138,U1738205,U1738207,and 11851305)+4 种基金the 100 Talents Program of Chinese Academy of Sciencesthe Youth Innovation Promotion Association CASthe Program for Innovative Talents and Entrepreneur in Jiangsusupported by the Swiss National Science Foundation(SNSF),Switzerlandthe National Institute for Nuclear Physics(INFN),Italy。
文摘The DArk Matter Particle Explorer(DAMPE)is a satellite-borne detector for high-energy cosmic rays and y-rays.To fully understand the detector performance and obtain reliable physical results,extensive simulations of the detector are necessary.The simulations are particularly important for the data analysis of cosmic ray nuclei,which relies closely on the hadronic and nuclear interactions of particles in the detector material.Widely adopted simulation softwares include the GEANT4 and FLUKA,both of which have been implemented for the DAMPE simulation tool.Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares.Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis.
基金funded by the National Key Research and Development Program of China (2016YFA0400201)supported by the National Natural Science Foundation of China (11673047,11673075, 11303107, U1738127 and U1738205)
文摘The DArk Matter Particle Explorer(DAMPE) is a space-borne apparatus for detecting the highenergy cosmic-ray-like electrons, γ-rays, protons and heavy ions. The Plastic Scintillator Detector(PSD)is the top-most sub-detector of the DAMPE. The PSD is designed to measure the charge of incident highenergy particles and it also serves as a veto detector for discriminating γ-rays from charged particles. In this paper, a PSD on-orbit calibration procedure is described, which includes the five steps of pedestal, dynode correlation, response to minimum-ionizing particles, light attenuation function and energy reconstruction.A method for reconstructing the charge of incident high energy cosmic-ray particles is introduced. The detection efficiency of each PSD strip is verified to be above 99.5%; the total efficiency of the PSD for charged particles is above 99.99%.
基金financial support from the Joint Research Fund in Astronomy under a cooperative agreement between the National Natural Science Foundation of China and the Chinese Academy of Sciences (Grant No. U1631242)the National Natural Science Foundation of China (Grant Nos. 11503028 and 11403028)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB23040400)the National Basic Research Program (973 Program) of China (2014CB845800)
文摘POLAR is a compact space-borne detector initially designed to measure the polarization of hard X-rays emitted from Gamma-Ray Bursts in the energy range 50–500 ke V.This instrument was launched successfully onboard the Chinese space laboratory Tiangong-2(TG-2) on 2016 September 15.After being switched on a few days later,tens of gigabytes of raw detection data were produced in-orbit by POLAR and transferred to the ground every day.Before the launch date,a full pipeline and related software were designed and developed for the purpose of quickly pre-processing all the raw data from POLAR,which include both science data and engineering data,then to generate the high level scientific data products that are suitable for later science analysis.This pipeline has been successfully applied for use by the POLAR Science Data Center in the Institute of High Energy Physics(IHEP) after POLAR was launched and switched on.A detailed introduction to the pipeline and some of the core relevant algorithms are presented in this paper.
基金the HXMT mission,a project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)supported by the National Key R&D Program of China(2016YFA0400800)the National Natural Science Foundation of China(Grant Nos.11673023,U1838201,U1838115,U1838111,U1838202,11733009 and U1838108)。
文摘We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040400)the National Natural Science Foundation of China(Grant Nos.11403026,11503028and 11673023)+4 种基金the National Basic Research Program of China(973 program,Grant No.2014CB845800)the National Thousand Young Talents program of Chinafunded by China National Space Administration(CNSA)the Chinese Academy of Sciences(CAS)the University of Geneva(UNIGE)
文摘Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts（GRBs） and electromagnetic（EM） counterparts of gravitational waves（GWs）. Based on near real-time Fermi/GBM data, we developed a low-latency pipeline to automatically calculate the temporal and spectral properties of GRBs. With this pipeline, some important parameters can be obtained, such as T_（90） and fluence, within ～ 20 min after the GRB trigger.For ～ 90% of GRBs, T90 and fluence are consistent with the GBM catalog results within 2σ errors.This pipeline has been used by the Gamma-ray Bursts Polarimeter（POLAR） and the Insight Hard Xray Modulation Telescope（Insight-HXMT） to follow up the bursts of interest. For GRB 170817 A, the first EM counterpart of GW events detected by Fermi/GBM and INTEGRAL/SPI-ACS, the pipeline gave T90 and spectral information 21 min after the GBM trigger, providing important information for POLAR and Insight-HXMT observations.
文摘The patient was a 63-year-old female,who was diagnosed with advanced pancreatic cancer with mediastinal lymph node and lung metastases and pleural effusion in June 2019.First-line treatment with 6 cycles of gemcitabine plus tegafur with best response of partial response.Second-line treatment was 4 cycles of nab-paclitaxel monotherapy ended up with disease progression.Third-line treatment was sintilimab with anlotinib for 10 cycles.The patient's condition has achieved clinical complete remission so far.
基金Financial support provided by the Fundamental Research Funds for the Central Universities of China(N2225022)is gratefully acknowledged.
文摘The velocity distribution of sinter and gas in vertical cooling furnace(VCF)has an important influence on gas-solid heat transfer.Based on the slot model of single hopper in the VCF of Meishan Iron and Steel Co.,Ltd.,the velocity and particle size distribution of sinter and the velocity and pressure distribution of gas were studied using a computational fluid dynamics-discrete element method model to obtain the gas-solid flow rule in the VCF.The results showed that the velocity of sinter near the wall and the edge of vent cowl was lower than that in the rest of the same plane.Therefore,the rectangular section of the vertical cooling furnace can be divided into a quasi-static zone,a plug flow zone and a convergent flow zone according to the flow velocity of the sinter.The average particle size and the void fraction of sinter bed were distributed in"W"and"V"shape along the width direction,respectively.The distribution of gas velocity in the furnace cavity was uneven,and the high-velocity area gradually changed from the center to the edge of the furnace cavity with the rise of gas.Reducing the ratio of edge to center gas flow from 2.7∶1 to 0.7∶1 could improve the gas velocity,but could not change the gas velocity distribution.The gas velocity distribution was more affected by the average particle size distribution of the sinter bed.It was suggested that measures need be taken to adjust it to improve the gas velocity distribution in the VCF.
文摘The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.
文摘Objective: To explore the feasibility of the submental island flap in the repair of hypopharyngeal defects.Methods: We collected wet specimens of fresh cadaveric heads from the Han Chinese adult population for applied anatomy of the submental island flap, and followed five patients with pyriform sinus carcinoma after reconstruction surgery using submental island flaps.Results: We found that the average length and width of the submental island flaps were (65.20 ± 11.69) mm and (46.70 ± 6.59) mm, respectively.The skin flap in all five patients survived after surgery, and tracheal tubes and gastric tubes were removed 7-36 days after surgery.Patients were followed up for 24-42 months, pharyngeal flaps grew well, and speech and swallowing functions were satisfactory.Conclusion: The submental island flap is a preferred material for the repair of hypopharyngeal defects after hypopharyngeal carcinoma resection, because of good blood supply, easy harvesting, and high survival rate.
基金the Na-tional Key Research and Development Program of China(No.2016YFA0400200)the National Natural Science Foundation of China(Nos.11722328,11525313,U1738205,and 11851305)the 100 Talents Program of Chinese Academy of Sciences.
文摘Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.
