Ovarian cancer is one of the female genital malignant tumors. Because its early clinical symptoms axe not obvious and there is no specific early diagnosis method, about 70% of patients are in advanced stage (stage II...Ovarian cancer is one of the female genital malignant tumors. Because its early clinical symptoms axe not obvious and there is no specific early diagnosis method, about 70% of patients are in advanced stage (stage III-IV) at the time of diagnosis. Ovarian cancer mortality is the highest in female reproductive system tumor. According to the 2017 edition of the National Comprehensive Cancer Network (NCCN) published in the "Ophthalmic Cancer Clinical Practice Guide", the main treatment plan is surgery-based, postoperative adjuvant chemotherapy and other comprehensive treatment. Ovarian cancer is similar to "Jia Ju" in traditional Chinese medicine. In recent years, traditional Chinese medicine has been widely used in clinical practice. Postoperative patients with Chinese medicine, acupuncture, et al. promote rapid recovery, and traditional Chinese medical methods can also reduce the side effects caused by radiotherapy and chemotherapy.展开更多
Localized corrosion of aluminum(Al)alloys,such as pitting corrosion,intergranular corrosion,and stress corrosion cracking is closely related to the micro-galvanic corrosion between the second phase and the Al matrix.U...Localized corrosion of aluminum(Al)alloys,such as pitting corrosion,intergranular corrosion,and stress corrosion cracking is closely related to the micro-galvanic corrosion between the second phase and the Al matrix.Using high-resolution transmission electron microscopy and first principles calculations,the factors that affect corrosion mechanisms of the second phase in Al alloys at micro-scale and atomic-scale were examined,including the composition and structure of second phase,pH of the environment,stress and adsorption behavior of adsorbates(such as Cl^(−),H_(2)O,OH−and O_(2)^(−).展开更多
Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors ...Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors the transient gamma-ray sky in the multi-mes-senger astronomy era.A compact CubeSat gamma-ray detector,including its hardware and firmware,was designed and implemented for the mission.The detector employs four Gd 2 Al 2 Ga 3 O 12:Ce(GAGG:Ce)scintillators coupled with four silicon photomultiplier(SiPM)arrays to achieve a high gamma-ray detection efficiency between 10 keV and 2 MeV with low power and small dimensions.The first detector designed by the undergraduate student team onboard a commercial CubeSat was launched into a Sun-synchronous orbit on October 29,2018.The detector was in a normal observation state and accumulated data for approximately one month after on-orbit functional and performance tests,which were conducted in 2019.展开更多
The phenomenon of gamma-ray burst (GRB) spectral lags is very common, but a definitive explanation has not yet been given. From a sample of 82 GRB pulses we find that the spectral lags are correlated with the pulse ...The phenomenon of gamma-ray burst (GRB) spectral lags is very common, but a definitive explanation has not yet been given. From a sample of 82 GRB pulses we find that the spectral lags are correlated with the pulse widths, however, there is no correlation between the relative spectral lags and the relative pulse widths. We suspect that the correlations between spectral lags and pulse widths might be caused by the Lorentz factor of the GRBs concerned. Our analysis on the relative quantities suggests that the intrinsic spectral lag might reflect other aspect of pulses than the aspect associated with the dynamical time of shocks or that associated with the time delay due to the curvature effect.展开更多
BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and H...BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.展开更多
All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clu...All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clusters limit the charge-transport behaviors.Herein,the defect halide perovskite based on trivalent Bi^(3+)is expanded to Cs_(3)Bi_(2)I_(6)Br_(3)(CBIB).Centimeter-size CBIB single crystal(Φ15×70 mm^(3))was grown by the vertical Bridgeman method.The powder X-ray diffraction analysis shows that CBIB has structure with lattice parameters of a=b=8.223Å,c=10.024Å,α=β=90°andγ=120°.The density functional theory(DFT)calculations demonstrate that the charge density distribution was enhanced after the dimensional expansion.The enhancement of carrier transport ability of(00l)in-plane is characterized before and after dimensional improvement.The obtained CBIB(001)exhibited an electron mobility up to 40.03 cm^(2)V^(−1)s^(−1)by time-of-flight(TOF)technique,higher than 26.46 cm^(2)V^(−1)s^(−1)of CBI(001).Furthermore,the X-ray sensitivity increases from 707.81μC Gy^(−1)cm^(−2)for CBI(001)to 3194.59μC Gy−1 cm^(−2)for CBIB(001).This research will deepen our understanding of Bi-based perovskite materials and afford more promising strategies for lead-free perovskite optoelectronic devices modification.展开更多
BACKGROUND Prophylactic enterostomy surgery is a common surgical approach used to reduce the risk of anastomotic leakage in patients who have undergone partial intestinal resection due to trauma or tumors.However,the ...BACKGROUND Prophylactic enterostomy surgery is a common surgical approach used to reduce the risk of anastomotic leakage in patients who have undergone partial intestinal resection due to trauma or tumors.However,the traditional interrupted suturing technique used in enterostomy closure surgery has several issues,including longer surgical incisions and higher incision tension,which can increase the risk of postoperative complications.To address these issues,scholars have proposed the use of a“gunsight suture”technique.This technique involves using a gunsight incision instead of a traditional linear incision,leaving a gap in the center for the drainage of blood and fluid to reduce the risk of infection.Building on this technique,we propose an improved gunsight suture technique.A drainage tube is placed at the lowest point of the incision and close the gap in the center of the gunsight suture,which theoretically facilitates early postoperative mobility and reduces the burden of dressing changes,thereby reducing the risk of postoperative complications.AIM To compare the effectiveness of improved gunsight suture technique with traditional interrupted suture in closing intestinal stomas.METHODS In this study,a retrospective,single-center case analysis was conducted on 270 patients who underwent prophylactic ileostomy closure surgery at the Department of Colorectal Surgery of Qilu Hospital from April 2017 to December 2021.The patients were divided into two groups:135 patients received sutures using the improved gunsight method,while the remaining 135 patients were sutured with the traditional interrupted suture method.We collected data on a variety of parameters,such as operation time,postoperative pain score,body temperature,length of hospital stays,laboratory indicators,incidence of incisional complications,number of wound dressing changes,and hospitalization costs.Non-parametric tests and chi-square tests were utilized for data analysis.RESULTS There were no statistically significant differences in general patient information between the two groups,including the interval between the first surgery and the stoma closure[132(105,184)d vs 134(109,181)d,P=0.63],gender ratio(0.64 vs 0.69,P=0.44),age[62(52,68)years vs 60(52,68)years,P=0.33],preoperative body mass index(BMI)[23.83(21.60,25.95)kg/m²vs 23.12(20.94,25.06)kg/m²,P=0.17].The incidence of incision infection in the improved gunsight suture group tended to be lower than that in the traditional interrupted suture group[(n=2/135,1.4%)vs(n=10/135,7.4%),P<0.05],and the postoperative hospital stay in the improved gunsight suture group was significantly shorter than that in the traditional interrupted suture group[5(4,7)d vs 7(6,8)d,P<0.05].Additionally,the surgical cost in the modified gunsight suture group was slightly lower than that in the traditional suture group[4840(4330,5138)yuan vs 4980(4726,5221)yuan,P>0.05],but there was no significant difference in the total hospitalization cost between the two groups.CONCLUSION In stoma closure surgery,the improved gunsight technique can reduce the incision infection rate,shorten the postoperative hospital stay,reduce wound tension,and provide better wound cosmetic effects compared to traditional interrupted suture.展开更多
BACKGROUND Autoimmune pancreatitis(AIP)is a particular type of chronic pancreatitis,and steroid treatment of AIP is effective.Spontaneous remission(SR)of AIP without steroids is relatively rare.The international conse...BACKGROUND Autoimmune pancreatitis(AIP)is a particular type of chronic pancreatitis,and steroid treatment of AIP is effective.Spontaneous remission(SR)of AIP without steroids is relatively rare.The international consensus for the treatment of autoimmune pancreatitis suggests that patients with AIP with obstructive jaundice,abdominal pain,and back pain related to the pancreas or the bile duct should be treated with steroids;most asymptomatic patients with AIP may improve without steroids.However,in our clinical work,we found that the clinical characteristics of AIP patients with SR vary.Four of these cases are described here.In addition,to our knowledge,there is no previously published report of dynamic imaging before and after SR of AIP at present.CASE SUMMARY We present the cases of four patients with AIP(two females and two males)in which the AIP improved spontaneously without steroid treatment.Two patients were asymptomatic,one patient had abdominal pain with obstructive jaundice,and one patient had intermittent right upper abdominal pain.Three patients presented with localized pancreatic enlargement and one with diffuse pancreatic enlargement.In addition to the pancreatic lesions,bile duct involvement was seen in two patients,and no extra-pancreatic organ involvement was found in the other two patients.The serum IgG4 level of all patients was more than twice the normal level.After SR in the four patients,the affected pancreases exhibited three types of image features:Return to normal,progressive fibrosis,and atrophy and calcification.CONCLUSION The clinical features of SR in our four patients with AIP differ,but the imaging findings share some characteristics.After SR,in some cases the affected pancreas could return to normal,although some patients suffer from progressive fibrosis and atrophy as well as calcification.展开更多
The growing observed evidence shows that the long-and short-duration gamma-ray bursts(GRBs) originate from massive star core-collapse and the merger of compact stars,respectively.GRB 201221 D is a short-duration GRB l...The growing observed evidence shows that the long-and short-duration gamma-ray bursts(GRBs) originate from massive star core-collapse and the merger of compact stars,respectively.GRB 201221 D is a short-duration GRB lasting~0.1 s without extended emission at high redshift z=1.046.By analyzing data observed with the Swift/BAT and Fermi/GBM,we find that a cutoff power-law model can adequately fit the spectrum with a soft E=113keV,and isotropic energy E=1.36× 10erg.In order to reveal the possible physical origin of GRB 201221 D,we adopted multi-wavelength criteria(e.g.,Amati relation,ε-parameter,amplitude parameter,local event rate density,luminosity function,and properties of the host galaxy),and find that most of the observations of GRB 201221 D favor a compact star merger origin.Moreover,we find that α is larger than 2+βin the prompt emission phase which suggests that the emission region is possibly undergoing acceleration during the prompt emission phase with a Poynting-flux-dominated jet.展开更多
The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection.Factors which determine the electric field distribution are not o...The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection.Factors which determine the electric field distribution are not only electric contact,but also intrinsic defects,especially grown-in twin boundaries.Here,the electric field distribution around twin boundaries is investigated in a CdZnTe bicrystal detector with a{111}–{111}twin plane using the Pockels electro-optic effect.The results of laser beam induced current pulses are also obtained by the transient current technique,and we discuss the influence of the twin boundary on the electric field evolution.These studies reveal a significant distortion of the electric field,which is attributed to the buildup of space charges at twin boundaries.Also,the position of these space charge regions depends on the polarity of the detector bias.An energy band model based on the formation of an n–n+–n junction across the twin boundary has been established to explain the observed results.展开更多
Fast radio bursts(FRBs)are extragalactic radio transients with millisecond duration and brightness temperature.An FRB-associated X-ray burst(XRB)was recently found to arise from the Galactic magnetar SGR J1935+2154.Fo...Fast radio bursts(FRBs)are extragalactic radio transients with millisecond duration and brightness temperature.An FRB-associated X-ray burst(XRB)was recently found to arise from the Galactic magnetar SGR J1935+2154.Following the model of Dai,in which an FRB may originate from a magnetar encountering an asteroid,we focus on explaining the spectrum of the XRB associated with FRB 200428 from SGR J1935+2154.Collisions between asteroidal fragments and the magnetar surface produce a fireball,which further expands relativistically.Due to the velocity difference among some shells in the fireball,internal shocks would form far away from the magnetar,and further emit X-ray emission.We propose that the FRB-associated XRB can be produced by synchrotron emission from the internal shocks,and then constrain the physical parameters by the observed XRB spectrum.展开更多
Giant flares(GFs)are unusual bursts from soft gamma-ray repeaters(SGRs)that release an enormous amount of energy in a fraction of a second.The afterglow emission of these SGR-GFs or GF candidates is a highly beneficia...Giant flares(GFs)are unusual bursts from soft gamma-ray repeaters(SGRs)that release an enormous amount of energy in a fraction of a second.The afterglow emission of these SGR-GFs or GF candidates is a highly beneficial means of discerning their composition,relativistic speed and emission mechanisms.GRB 200415A is a recent GF candidate observed in a direction coincident with the nearby Sculptor galaxy at 3.5 Mpc.In this work,we searched for transient gamma-ray emission in past observations by Fermi-LAT in the direction of GRB 200415A.These observations confirm that GRB 200415A is observed as a transient GeV source only once.A pure pair-plasma fireball cannot provide the required energy for the interpretation of GeV afterglow emission and a baryonic poor outflow is additionally needed to explain the afterglow emission.A baryonic rich outflow is also viable,as it can explain the variability and observed quasi-thermal spectrum of the prompt emission if dissipation is happening below the photosphere via internal shocks.Using the peak energy(Ep)of the time-resolved prompt emission spectra and their fluxes(Fp),we found a correlation between Ep and Fp or isotropic luminosity Liso for GRB 200415A.This supports the intrinsic nature of Ep-Liso correlation found in SGRs-GFs,hence favoring a baryonic poor outflow.Our results also indicate a different mechanism at work during the initial spike,and that the evolution of the prompt emission spectral properties in this outflow would be intrinsically due to the injection process.展开更多
Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B ...Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B by examining both its temporal and spectral consistency with the predictions of the model.As one of the recently confirmed GRBs observed by our GRID CubeSat mission,GRB 220408B is noteworthy as it exhibits three apparently similar emission episodes.Furthermore,the similarities are reinforced by their strong temporal correlations and similar features in terms of spectral evolution and spectral lags.Our analysis demonstrates that these features can be well explained by the modulated emission of a Fast-Rise-Exponential-Decay(FRED)shape light curve intrinsically produced by a precessing jet with a precession period of 18.4_(-0.2)~(+0.2)s,a nutation period of11.1_(-0.2)~(+0.2)s and viewed off-axis.This study provides a straightforward explanation for the complex yet similar multiepisode GRB light curves.展开更多
The afterglow of GRB 170817 A has been detected for more than three years,but the origin of the multi-band afterglow light curves remains under debate.A classical top-hat jet model is faced with difficulties in produc...The afterglow of GRB 170817 A has been detected for more than three years,but the origin of the multi-band afterglow light curves remains under debate.A classical top-hat jet model is faced with difficulties in producing a shallow rise of the afterglow light curves as observed(E_(v) ∝ T^(0.8)).Here we reconsider the model of stratified ejecta with an energy profile of E(> Γβ)=E_0(Γβ)^(-k) as the origin of the afterglow light curves of the burst,where Γ and β are the Lorentz factor and speed of the ejecta,respectively.k is the power-law slope of the energy profile.We consider that the ejecta are collimated into jets.Two kinds of jet evolutions are investigated,including a lateral-spreading jet and a non-lateral-spreading jet.We fit the multi-band afterglow light curves,including the X-ray data at one thousand days post-burst,and find that both the models of the spreading and non-spreading jets can fit the light curves well,but the observed angular size of the source and the apparent velocity of the flux centroid for the spreading jet model are beyond the observation limits,while the non-spreading jet model meets the observation limits.Some of the best-fit parameters for the non-spreading jet model,such as the number density of the circumburst medium~10^(-2) cm^(-3) and the total jet kinetic energy E ~ 4.8 × 10^(51) erg,also appear plausible.The best-fit slope of the jet energy profile is k ~7.1.Our results suggest that the afterglow of GRB 170817 A may arise from the stratified jet and that the lateral spreading of the jet is not significant.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
Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, ...Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.展开更多
Binary neutron star(NS)mergers may result in remnants of supra-massive or even stable NS,which have been supported indirectly by observed X-ray plateau of some gamma-ray burst(GRB)afterglows.Recently,Xue et al.(2019)d...Binary neutron star(NS)mergers may result in remnants of supra-massive or even stable NS,which have been supported indirectly by observed X-ray plateau of some gamma-ray burst(GRB)afterglows.Recently,Xue et al.(2019)discovered an X-ray transient CDF-S XT2 that is powered by a magnetar from merger of double NS via X-ray plateau and following stepper phase.However,the decay slope after the plateau emission is slightly larger than the theoretical value of spin-down in electromagnetic(EM)dominated by losing its rotation energy.In this paper,we assume that the feature of X-ray emission is caused by a supra-massive magnetar central engine for surviving thousands of seconds to collapse into a black hole.Within this scenario,we present the comparisons of the X-ray plateau luminosity,break time,and the parameters of magnetar between CDF-S XT2 and other short GRBs with internal plateau samples.By adopting the collapse time to constrain the equation of state(EOS),we find that three EOSs(GM1,DD2,and DDME2)are consistent with the observational data.On the other hand,if the most released rotation energy of magnetar is dominated by GW radiation,we also constrain the upper limit of ellipticity of NS for given EOS,and its range is[0.32-1.3]×10^(-3).Its GW signal cannot be detected by Advanced LIGO or even for more sensitive Einstein Telescope in the future.展开更多
The observations with Swift X-ray telescope (XRT) challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segme...The observations with Swift X-ray telescope (XRT) challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segment, a shallow decay segment, a normal decay segment, a jet-like steep decay segment, and sometimes erratic flares as well. The physical origin of the X-ray emission is highly debatable. We focus here on the physical origin of the X-ray emissions of GRBs 050318 and 060124. We present the XRT light curves and spectra of the two bursts. The light curve decay slopes of the two bursts are normal, and their relations to the spectral indices are consistent with the prediction of the standard forward shock model. The multi-wavelength light curves at 0.5 keV, 1.0 keV, 2.0 keV and 4.0 keV can be reproduced by this model with an isotropic kinetic energy Ek = 2.2 × 10^52 erg, εe = 0.04, εB = 0.01 for GRB 050318 and Ek = 4.2 × 10^53 erg, εe = 0.05, εB = 0.01 for GRB 060124. These facts suggest that the normal decay phases of the X-rays for the two bursts are of the forward shock origin.展开更多
Background:Sexual transmission among men who have sex with men(MSM)is the dominant route of HIV transmission in China.Extensive use of geosocial networking(GSN)smartphone application(app)has dramatically changed the p...Background:Sexual transmission among men who have sex with men(MSM)is the dominant route of HIV transmission in China.Extensive use of geosocial networking(GSN)smartphone application(app)has dramatically changed the pattern of sexual behaviors and HIV risk among MSM;but data on HIV incidence and the changing risk behaviors of GSN app-using MSM are limited.We aims to assess the HIV incidence and its correlates among gay GSN app-using MSM in China.Methods:We constructed an open cohort which was initiated and maintained using a GSN app to assess the HIV incidence among app-using MSM,recruited from June 2017 to December 2018.MSM completed an online questionnaire on their sociodemographic characteristics,sexual behaviors,recreational drug use and sexually transmitted infections status.Then each man had an HIV test,and those tested negatives were enrolled into the cohort.Participants completed follow-ups with additional HIV tests though the app during the study period,and were censored at HIV seroconversion or study end date.HIV incidence was calculated by dividing the sum of observed HIV seroconversions by the observed person-time.Univariate(Chi-square test and Fisher's exact test)and multivariate(proportional hazards regression)analyses were used to examine correlates of HIV incidence.Results:A total of 6957 HIV negative MSM were enrolled in the open cohort,37 seroconversions occurred among 1937 men contributing 1065 observed person-years:HIV incidence was 3.47 per 100 person-years[95%confidence interval(Cl):2.37-4.57].More than five sexual partners[hazard ratio(HR)=2.65,95%Cl:1.04-6.67],and sex with HIV positive partners(HR=3.82,95%Cl:1.16-12.64)in the preceding six months were positively associated with HIV seroconversion.Consistent condom use for anal sex(HR=0.27,95%Cl:0.07-0.96),and reporting insertive anal sex only(HR=0.23,95%Cl:0.08-0.62)in the preceding six months were protective factors for HIV seroconversion.Conclusions:Tailored interventions targeting app-using MSM are urgently needed given their high risk of HIV.As a new tool for accessing MSM at higher HIV risk,GSN smartphone app could play an important role in HIV research among MSM.展开更多
Objective To investigate the expression of centromere protein-C (CENP-C) in villus tissue of the first-trimester spontaneous abortion (SA) and the correlation study of CENP-C expression with chromosome segregation...Objective To investigate the expression of centromere protein-C (CENP-C) in villus tissue of the first-trimester spontaneous abortion (SA) and the correlation study of CENP-C expression with chromosome segregation. Methods Fluorescence in situ hybridization (FISH) and G-banded karyotype analysis were used to detect the numerical chromosome abnormality in 94 villus tissues of women with SA. The participants were separated into case group (n=30) and control group (n--30) according to the results with FISH. The qRT-PCR and Western blotting analysis were used to assess the expression level of CENP-C. Results Forty-eight (51.06%) cases had observed the numerical chromosome abnormality, including 30positive cases and the positive rate was 31.91%. The main types of variation included trisomy 16, 21, 22, X monosomy and triploid. The expression levels of CENP-C mRNA and protein in case group were statistically higher than that in control group (P〈0.05). Conclusion Expression of CENP-C in the villus tissues of women might be related to SA induced by chromosomal aneuploid.展开更多
文摘Ovarian cancer is one of the female genital malignant tumors. Because its early clinical symptoms axe not obvious and there is no specific early diagnosis method, about 70% of patients are in advanced stage (stage III-IV) at the time of diagnosis. Ovarian cancer mortality is the highest in female reproductive system tumor. According to the 2017 edition of the National Comprehensive Cancer Network (NCCN) published in the "Ophthalmic Cancer Clinical Practice Guide", the main treatment plan is surgery-based, postoperative adjuvant chemotherapy and other comprehensive treatment. Ovarian cancer is similar to "Jia Ju" in traditional Chinese medicine. In recent years, traditional Chinese medicine has been widely used in clinical practice. Postoperative patients with Chinese medicine, acupuncture, et al. promote rapid recovery, and traditional Chinese medical methods can also reduce the side effects caused by radiotherapy and chemotherapy.
基金financial support from the National Natural Science Foundation of China (No. 52171077)。
文摘Localized corrosion of aluminum(Al)alloys,such as pitting corrosion,intergranular corrosion,and stress corrosion cracking is closely related to the micro-galvanic corrosion between the second phase and the Al matrix.Using high-resolution transmission electron microscopy and first principles calculations,the factors that affect corrosion mechanisms of the second phase in Al alloys at micro-scale and atomic-scale were examined,including the composition and structure of second phase,pH of the environment,stress and adsorption behavior of adsorbates(such as Cl^(−),H_(2)O,OH−and O_(2)^(−).
基金supported by the Tsinghua University Initiative Scientific Research Program,the National Natural Science Foundation of China(Nos.11633003,12025301,and 11821303)the National Key R&D Program of China(Nos.2018YFA0404502 and 2016YFA040080X).
文摘Gamma-Ray Integrated Detectors(GRID)mis-sion is a student project designed to use multiple gamma-ray detectors carried by nanosatellites(CubeSats),forming a full-time all-sky gamma-ray detection network that monitors the transient gamma-ray sky in the multi-mes-senger astronomy era.A compact CubeSat gamma-ray detector,including its hardware and firmware,was designed and implemented for the mission.The detector employs four Gd 2 Al 2 Ga 3 O 12:Ce(GAGG:Ce)scintillators coupled with four silicon photomultiplier(SiPM)arrays to achieve a high gamma-ray detection efficiency between 10 keV and 2 MeV with low power and small dimensions.The first detector designed by the undergraduate student team onboard a commercial CubeSat was launched into a Sun-synchronous orbit on October 29,2018.The detector was in a normal observation state and accumulated data for approximately one month after on-orbit functional and performance tests,which were conducted in 2019.
基金the National Natural Science Foundation of China.
文摘The phenomenon of gamma-ray burst (GRB) spectral lags is very common, but a definitive explanation has not yet been given. From a sample of 82 GRB pulses we find that the spectral lags are correlated with the pulse widths, however, there is no correlation between the relative spectral lags and the relative pulse widths. We suspect that the correlations between spectral lags and pulse widths might be caused by the Lorentz factor of the GRBs concerned. Our analysis on the relative quantities suggests that the intrinsic spectral lag might reflect other aspect of pulses than the aspect associated with the dynamical time of shocks or that associated with the time delay due to the curvature effect.
基金Supported by the Key Research and Development Plan of Shaanxi Province,No.2021SF-298.
文摘BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.
基金supported by the National Natural Science Foundations of China(Nos.51872228,U2032170 and 51802262)the National Key Research and Development Program of China(2016YFE0115200 and 2016YFF0101301)+2 种基金the Natural Science Foundations of Shaanxi Province(2019JQ-459 and 2020JC-12)the Natural Science Basic Research Plan in Shaanxi Province of China(2019ZDLGY04-07)the Fundamental Research Funds for the Central Universities(D5000210906 and 3102020QD0408)。
文摘All-inorganic Cs_(3)Bi_(2)I_(9)(CBI)halide perovskites are sought to be candidate for photoelectrical materials because of their low toxicity and satisfactory stability.Unfortunately,the discrete molecular[Bi2I9]3−clusters limit the charge-transport behaviors.Herein,the defect halide perovskite based on trivalent Bi^(3+)is expanded to Cs_(3)Bi_(2)I_(6)Br_(3)(CBIB).Centimeter-size CBIB single crystal(Φ15×70 mm^(3))was grown by the vertical Bridgeman method.The powder X-ray diffraction analysis shows that CBIB has structure with lattice parameters of a=b=8.223Å,c=10.024Å,α=β=90°andγ=120°.The density functional theory(DFT)calculations demonstrate that the charge density distribution was enhanced after the dimensional expansion.The enhancement of carrier transport ability of(00l)in-plane is characterized before and after dimensional improvement.The obtained CBIB(001)exhibited an electron mobility up to 40.03 cm^(2)V^(−1)s^(−1)by time-of-flight(TOF)technique,higher than 26.46 cm^(2)V^(−1)s^(−1)of CBI(001).Furthermore,the X-ray sensitivity increases from 707.81μC Gy^(−1)cm^(−2)for CBI(001)to 3194.59μC Gy−1 cm^(−2)for CBIB(001).This research will deepen our understanding of Bi-based perovskite materials and afford more promising strategies for lead-free perovskite optoelectronic devices modification.
基金the Natural Science Foundation of Shandong Province,No.ZR2020MH257。
文摘BACKGROUND Prophylactic enterostomy surgery is a common surgical approach used to reduce the risk of anastomotic leakage in patients who have undergone partial intestinal resection due to trauma or tumors.However,the traditional interrupted suturing technique used in enterostomy closure surgery has several issues,including longer surgical incisions and higher incision tension,which can increase the risk of postoperative complications.To address these issues,scholars have proposed the use of a“gunsight suture”technique.This technique involves using a gunsight incision instead of a traditional linear incision,leaving a gap in the center for the drainage of blood and fluid to reduce the risk of infection.Building on this technique,we propose an improved gunsight suture technique.A drainage tube is placed at the lowest point of the incision and close the gap in the center of the gunsight suture,which theoretically facilitates early postoperative mobility and reduces the burden of dressing changes,thereby reducing the risk of postoperative complications.AIM To compare the effectiveness of improved gunsight suture technique with traditional interrupted suture in closing intestinal stomas.METHODS In this study,a retrospective,single-center case analysis was conducted on 270 patients who underwent prophylactic ileostomy closure surgery at the Department of Colorectal Surgery of Qilu Hospital from April 2017 to December 2021.The patients were divided into two groups:135 patients received sutures using the improved gunsight method,while the remaining 135 patients were sutured with the traditional interrupted suture method.We collected data on a variety of parameters,such as operation time,postoperative pain score,body temperature,length of hospital stays,laboratory indicators,incidence of incisional complications,number of wound dressing changes,and hospitalization costs.Non-parametric tests and chi-square tests were utilized for data analysis.RESULTS There were no statistically significant differences in general patient information between the two groups,including the interval between the first surgery and the stoma closure[132(105,184)d vs 134(109,181)d,P=0.63],gender ratio(0.64 vs 0.69,P=0.44),age[62(52,68)years vs 60(52,68)years,P=0.33],preoperative body mass index(BMI)[23.83(21.60,25.95)kg/m²vs 23.12(20.94,25.06)kg/m²,P=0.17].The incidence of incision infection in the improved gunsight suture group tended to be lower than that in the traditional interrupted suture group[(n=2/135,1.4%)vs(n=10/135,7.4%),P<0.05],and the postoperative hospital stay in the improved gunsight suture group was significantly shorter than that in the traditional interrupted suture group[5(4,7)d vs 7(6,8)d,P<0.05].Additionally,the surgical cost in the modified gunsight suture group was slightly lower than that in the traditional suture group[4840(4330,5138)yuan vs 4980(4726,5221)yuan,P>0.05],but there was no significant difference in the total hospitalization cost between the two groups.CONCLUSION In stoma closure surgery,the improved gunsight technique can reduce the incision infection rate,shorten the postoperative hospital stay,reduce wound tension,and provide better wound cosmetic effects compared to traditional interrupted suture.
文摘BACKGROUND Autoimmune pancreatitis(AIP)is a particular type of chronic pancreatitis,and steroid treatment of AIP is effective.Spontaneous remission(SR)of AIP without steroids is relatively rare.The international consensus for the treatment of autoimmune pancreatitis suggests that patients with AIP with obstructive jaundice,abdominal pain,and back pain related to the pancreas or the bile duct should be treated with steroids;most asymptomatic patients with AIP may improve without steroids.However,in our clinical work,we found that the clinical characteristics of AIP patients with SR vary.Four of these cases are described here.In addition,to our knowledge,there is no previously published report of dynamic imaging before and after SR of AIP at present.CASE SUMMARY We present the cases of four patients with AIP(two females and two males)in which the AIP improved spontaneously without steroid treatment.Two patients were asymptomatic,one patient had abdominal pain with obstructive jaundice,and one patient had intermittent right upper abdominal pain.Three patients presented with localized pancreatic enlargement and one with diffuse pancreatic enlargement.In addition to the pancreatic lesions,bile duct involvement was seen in two patients,and no extra-pancreatic organ involvement was found in the other two patients.The serum IgG4 level of all patients was more than twice the normal level.After SR in the four patients,the affected pancreases exhibited three types of image features:Return to normal,progressive fibrosis,and atrophy and calcification.CONCLUSION The clinical features of SR in our four patients with AIP differ,but the imaging findings share some characteristics.After SR,in some cases the affected pancreas could return to normal,although some patients suffer from progressive fibrosis and atrophy as well as calcification.
基金supported by the National Natural Science Foundation of China (grant Nos. 11922301 and 12133003)the Guangxi Science Foundation (grant Nos. 2017GXNSFFA198008 and AD17129006)+6 种基金support by the Program of Bagui Young Scholars Program, and special funding for Guangxi distinguished professors (Bagui Yingcai & Bagui Xuezhe)support by the National Key Research and Development Programs of China (2018YFA0404204)the National Natural Science Foundation of China (grant Nos. 11833003 and U2038105)the Program for Innovative Talents, Entrepreneur in Jiangsusupport by the Strategic Priority Research Program of the Chinese Academy of Sciences (grant Nos. XDA15310300, XDA15052100 and XDB23040000)support by the National Natural Science Foundation of China (grant Nos. 12041306 and 12103089)the Natural Science Foundation of Jiangsu Province (grant No. BK20211000)。
文摘The growing observed evidence shows that the long-and short-duration gamma-ray bursts(GRBs) originate from massive star core-collapse and the merger of compact stars,respectively.GRB 201221 D is a short-duration GRB lasting~0.1 s without extended emission at high redshift z=1.046.By analyzing data observed with the Swift/BAT and Fermi/GBM,we find that a cutoff power-law model can adequately fit the spectrum with a soft E=113keV,and isotropic energy E=1.36× 10erg.In order to reveal the possible physical origin of GRB 201221 D,we adopted multi-wavelength criteria(e.g.,Amati relation,ε-parameter,amplitude parameter,local event rate density,luminosity function,and properties of the host galaxy),and find that most of the observations of GRB 201221 D favor a compact star merger origin.Moreover,we find that α is larger than 2+βin the prompt emission phase which suggests that the emission region is possibly undergoing acceleration during the prompt emission phase with a Poynting-flux-dominated jet.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1631116 and 51702271)the National Key Research and Development Program of China(Grant No.2016YFE0115200)+3 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2017KW-029)Austrian Academic Exchange Service(ÖD-WTZ)through project CN 02/2016the Fundamental Research Funds for the Central Universities of China(Grant Nos.3102017zy057 and 3102018jcc036)the Young and Middle-aged Teachers Education and Scientific Research Foundation of Fujian Province,China(Grant No.JAT170407)
文摘The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection.Factors which determine the electric field distribution are not only electric contact,but also intrinsic defects,especially grown-in twin boundaries.Here,the electric field distribution around twin boundaries is investigated in a CdZnTe bicrystal detector with a{111}–{111}twin plane using the Pockels electro-optic effect.The results of laser beam induced current pulses are also obtained by the transient current technique,and we discuss the influence of the twin boundary on the electric field evolution.These studies reveal a significant distortion of the electric field,which is attributed to the buildup of space charges at twin boundaries.Also,the position of these space charge regions depends on the polarity of the detector bias.An energy band model based on the formation of an n–n+–n junction across the twin boundary has been established to explain the observed results.
基金supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0402600,2018YFA0404204)the National SKA Program of China(Grant No.2020SKA0120300)+9 种基金the National Natural Science Foundation of China(NSFC,Grant Nos.11833003,U2038105)supported by the National Natural Science Foundation of China(NSFC,Grant No.12003028)support from the National Natural Science Foundation of China(NSFC,Grant No.U1838113)the National Natural Science Foundation of China(NSFC,Grant Nos.11833003 and U2038105)the Program for Innovative Talents,Entrepreneur in JiangsuYunnan University(Grant No.C176220100087)support by Fundamental Research Funds for the Central Universities(14380046)the National Key Research and Development Programs of China(2018YFA0404204)the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-B11the Program for Innovative Talents,Entrepreneur in Jiangsu。
文摘Fast radio bursts(FRBs)are extragalactic radio transients with millisecond duration and brightness temperature.An FRB-associated X-ray burst(XRB)was recently found to arise from the Galactic magnetar SGR J1935+2154.Following the model of Dai,in which an FRB may originate from a magnetar encountering an asteroid,we focus on explaining the spectrum of the XRB associated with FRB 200428 from SGR J1935+2154.Collisions between asteroidal fragments and the magnetar surface produce a fireball,which further expands relativistically.Due to the velocity difference among some shells in the fireball,internal shocks would form far away from the magnetar,and further emit X-ray emission.We propose that the FRB-associated XRB can be produced by synchrotron emission from the internal shocks,and then constrain the physical parameters by the observed XRB spectrum.
基金support by the Fundamental Research Funds for the Central Universities(14380035)supported by National Key Research and Development Programs of China(2018YFA0404204)+3 种基金the National Natural Science Foundation of China(Grant Nos.11833003,U1838105 and U1831135)the Program for Innovative Talents,Entrepreneur in Jiangsuthe Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDB23040400)BRICS grant DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G)for the financial support。
文摘Giant flares(GFs)are unusual bursts from soft gamma-ray repeaters(SGRs)that release an enormous amount of energy in a fraction of a second.The afterglow emission of these SGR-GFs or GF candidates is a highly beneficial means of discerning their composition,relativistic speed and emission mechanisms.GRB 200415A is a recent GF candidate observed in a direction coincident with the nearby Sculptor galaxy at 3.5 Mpc.In this work,we searched for transient gamma-ray emission in past observations by Fermi-LAT in the direction of GRB 200415A.These observations confirm that GRB 200415A is observed as a transient GeV source only once.A pure pair-plasma fireball cannot provide the required energy for the interpretation of GeV afterglow emission and a baryonic poor outflow is additionally needed to explain the afterglow emission.A baryonic rich outflow is also viable,as it can explain the variability and observed quasi-thermal spectrum of the prompt emission if dissipation is happening below the photosphere via internal shocks.Using the peak energy(Ep)of the time-resolved prompt emission spectra and their fluxes(Fp),we found a correlation between Ep and Fp or isotropic luminosity Liso for GRB 200415A.This supports the intrinsic nature of Ep-Liso correlation found in SGRs-GFs,hence favoring a baryonic poor outflow.Our results also indicate a different mechanism at work during the initial spike,and that the evolution of the prompt emission spectral properties in this outflow would be intrinsically due to the injection process.
基金support by the National Key Research and Development Programs of China(2022YFF0711404,2022SKA0130102)the National SKA Program of China(2022SKA0130100)+4 种基金the National Natural Science Foundation of China(grant Nos.11833003,U2038105,U1831135,12121003)the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-B11the Fundamental Research Funds for the Central Universitiesthe Program for Innovative Talents and Entrepreneur in Jiangsusupported by the National Postdoctoral Program for Innovative Talents(grant No.BX20200164)。
文摘Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B by examining both its temporal and spectral consistency with the predictions of the model.As one of the recently confirmed GRBs observed by our GRID CubeSat mission,GRB 220408B is noteworthy as it exhibits three apparently similar emission episodes.Furthermore,the similarities are reinforced by their strong temporal correlations and similar features in terms of spectral evolution and spectral lags.Our analysis demonstrates that these features can be well explained by the modulated emission of a Fast-Rise-Exponential-Decay(FRED)shape light curve intrinsically produced by a precessing jet with a precession period of 18.4_(-0.2)~(+0.2)s,a nutation period of11.1_(-0.2)~(+0.2)s and viewed off-axis.This study provides a straightforward explanation for the complex yet similar multiepisode GRB light curves.
基金supported by the National Natural Science Foundation of China(Nos.U1831135 and 11833003)Yunnan Natural Science Foundation(2014FB188)+2 种基金support by the National Key Research and Development Programs of China(2018YFA0404204)the National Natural Science Foundation of China(grant Nos.11833003 and U2038105)the Program for Innovative Talents,Entrepreneur in Jiangsu。
文摘The afterglow of GRB 170817 A has been detected for more than three years,but the origin of the multi-band afterglow light curves remains under debate.A classical top-hat jet model is faced with difficulties in producing a shallow rise of the afterglow light curves as observed(E_(v) ∝ T^(0.8)).Here we reconsider the model of stratified ejecta with an energy profile of E(> Γβ)=E_0(Γβ)^(-k) as the origin of the afterglow light curves of the burst,where Γ and β are the Lorentz factor and speed of the ejecta,respectively.k is the power-law slope of the energy profile.We consider that the ejecta are collimated into jets.Two kinds of jet evolutions are investigated,including a lateral-spreading jet and a non-lateral-spreading jet.We fit the multi-band afterglow light curves,including the X-ray data at one thousand days post-burst,and find that both the models of the spreading and non-spreading jets can fit the light curves well,but the observed angular size of the source and the apparent velocity of the flux centroid for the spreading jet model are beyond the observation limits,while the non-spreading jet model meets the observation limits.Some of the best-fit parameters for the non-spreading jet model,such as the number density of the circumburst medium~10^(-2) cm^(-3) and the total jet kinetic energy E ~ 4.8 × 10^(51) erg,also appear plausible.The best-fit slope of the jet energy profile is k ~7.1.Our results suggest that the afterglow of GRB 170817 A may arise from the stratified jet and that the lateral spreading of the jet is not significant.
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.
基金supported by the National SKA Program of China (Grant Nos. 2020SKA0120100 and 2020SKA0120200)the National Natural Science Foundation of China (Grant Nos. 12041304, 11873067, 11988101, 12041303, 11725313, 11725314, 11833003, 12003028, 12041306, 12103089, U2031209, U2038105, and U1831207)+8 种基金the National Key Research and Development Program of China (Grant Nos. 2019YFA0405100, 2017YFA0402602, 2018YFA0404204, and 2016YFA0400801)Key Research Program of the Chinese Academy of Sciences (Grant No. QYZDJ-SSW-SLH021)Natural Science Foundation of Jiangsu Province (Grant No. BK20211000)Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, the Strategic Priority Research Program on Space Science, the Western Light Youth Project of Chinese Academy of Sciences (Grant Nos. XDA15360000, XDA15052700, and XDB23040400)funding from the MaxPlanck Partner Group, the science research grants from the China Manned Space Project (Grant Nos. CMS-CSST2021-B11 and CMS-CSST-2021-A11)PKU development (Grant No. 7101502590)support from the XPLORER PRIZEsupported by Fundamental Research Funds for the Central Universities (Grant No. 14380046)the Program for Innovative Talents, Entrepreneur in Jiangsu。
文摘Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.
基金supported by the National Natural Science Foundation of China(Grant Nos.11922301,11851304,11533003 and 11833003)the Guangxi Science Foundation(2017GXNSFFA198008,2018GXNSFGA281007 and AD17129006)+2 种基金support from a national program for young scholars in ChinaProgram for Innovative Talents and Entrepreneur in Jiangsuthe National Key Research and Development Program of China(2018YFA0404204)。
文摘Binary neutron star(NS)mergers may result in remnants of supra-massive or even stable NS,which have been supported indirectly by observed X-ray plateau of some gamma-ray burst(GRB)afterglows.Recently,Xue et al.(2019)discovered an X-ray transient CDF-S XT2 that is powered by a magnetar from merger of double NS via X-ray plateau and following stepper phase.However,the decay slope after the plateau emission is slightly larger than the theoretical value of spin-down in electromagnetic(EM)dominated by losing its rotation energy.In this paper,we assume that the feature of X-ray emission is caused by a supra-massive magnetar central engine for surviving thousands of seconds to collapse into a black hole.Within this scenario,we present the comparisons of the X-ray plateau luminosity,break time,and the parameters of magnetar between CDF-S XT2 and other short GRBs with internal plateau samples.By adopting the collapse time to constrain the equation of state(EOS),we find that three EOSs(GM1,DD2,and DDME2)are consistent with the observational data.On the other hand,if the most released rotation energy of magnetar is dominated by GW radiation,we also constrain the upper limit of ellipticity of NS for given EOS,and its range is[0.32-1.3]×10^(-3).Its GW signal cannot be detected by Advanced LIGO or even for more sensitive Einstein Telescope in the future.
基金the National Natural Science Foundation of China.
文摘The observations with Swift X-ray telescope (XRT) challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segment, a shallow decay segment, a normal decay segment, a jet-like steep decay segment, and sometimes erratic flares as well. The physical origin of the X-ray emission is highly debatable. We focus here on the physical origin of the X-ray emissions of GRBs 050318 and 060124. We present the XRT light curves and spectra of the two bursts. The light curve decay slopes of the two bursts are normal, and their relations to the spectral indices are consistent with the prediction of the standard forward shock model. The multi-wavelength light curves at 0.5 keV, 1.0 keV, 2.0 keV and 4.0 keV can be reproduced by this model with an isotropic kinetic energy Ek = 2.2 × 10^52 erg, εe = 0.04, εB = 0.01 for GRB 050318 and Ek = 4.2 × 10^53 erg, εe = 0.05, εB = 0.01 for GRB 060124. These facts suggest that the normal decay phases of the X-rays for the two bursts are of the forward shock origin.
基金funded by a grant from Beijing Municipal Science and Technology Project[D17110700670000]the funding body had no other input into the research.
文摘Background:Sexual transmission among men who have sex with men(MSM)is the dominant route of HIV transmission in China.Extensive use of geosocial networking(GSN)smartphone application(app)has dramatically changed the pattern of sexual behaviors and HIV risk among MSM;but data on HIV incidence and the changing risk behaviors of GSN app-using MSM are limited.We aims to assess the HIV incidence and its correlates among gay GSN app-using MSM in China.Methods:We constructed an open cohort which was initiated and maintained using a GSN app to assess the HIV incidence among app-using MSM,recruited from June 2017 to December 2018.MSM completed an online questionnaire on their sociodemographic characteristics,sexual behaviors,recreational drug use and sexually transmitted infections status.Then each man had an HIV test,and those tested negatives were enrolled into the cohort.Participants completed follow-ups with additional HIV tests though the app during the study period,and were censored at HIV seroconversion or study end date.HIV incidence was calculated by dividing the sum of observed HIV seroconversions by the observed person-time.Univariate(Chi-square test and Fisher's exact test)and multivariate(proportional hazards regression)analyses were used to examine correlates of HIV incidence.Results:A total of 6957 HIV negative MSM were enrolled in the open cohort,37 seroconversions occurred among 1937 men contributing 1065 observed person-years:HIV incidence was 3.47 per 100 person-years[95%confidence interval(Cl):2.37-4.57].More than five sexual partners[hazard ratio(HR)=2.65,95%Cl:1.04-6.67],and sex with HIV positive partners(HR=3.82,95%Cl:1.16-12.64)in the preceding six months were positively associated with HIV seroconversion.Consistent condom use for anal sex(HR=0.27,95%Cl:0.07-0.96),and reporting insertive anal sex only(HR=0.23,95%Cl:0.08-0.62)in the preceding six months were protective factors for HIV seroconversion.Conclusions:Tailored interventions targeting app-using MSM are urgently needed given their high risk of HIV.As a new tool for accessing MSM at higher HIV risk,GSN smartphone app could play an important role in HIV research among MSM.
基金supported by the Natural Science Foundation of Shanxi province[2012021035-1]
文摘Objective To investigate the expression of centromere protein-C (CENP-C) in villus tissue of the first-trimester spontaneous abortion (SA) and the correlation study of CENP-C expression with chromosome segregation. Methods Fluorescence in situ hybridization (FISH) and G-banded karyotype analysis were used to detect the numerical chromosome abnormality in 94 villus tissues of women with SA. The participants were separated into case group (n=30) and control group (n--30) according to the results with FISH. The qRT-PCR and Western blotting analysis were used to assess the expression level of CENP-C. Results Forty-eight (51.06%) cases had observed the numerical chromosome abnormality, including 30positive cases and the positive rate was 31.91%. The main types of variation included trisomy 16, 21, 22, X monosomy and triploid. The expression levels of CENP-C mRNA and protein in case group were statistically higher than that in control group (P〈0.05). Conclusion Expression of CENP-C in the villus tissues of women might be related to SA induced by chromosomal aneuploid.