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We have developed a lightweight tool, RapidGBM, featuring a web-based interface and capabilities of rapid calculation of Fermi Gamma-ray Burst Monitor (GBM) visibilities and performance of basic data analysis. It has two key features: (1) it can immediately check the visibility of Fermi-GBM for new transients, and (2) it can check the light curve and perform spectral analysis after the hourly Time-Tagged Event data are released. The visibility check and the response matrix generation required for spectral analysis can be achieved through the historical pointing file after the orbit calculation, even when the real-time pointing file is not yet available. As a case study, we apply the tool to EP240617a, an X-ray transient triggered by Einstein Probe (EP). We demonstrate the workflow of visibility checking, data processing, and spectral analysis for this event. The results suggest that EP240617a can be classified as an X-ray-rich gamma-ray burst and confirm the feasibility of using historical pointing files for rapid analysis. Further, we discuss possible physical interpretations of such events, including implications for jet launching and progenitor scenarios. Therefore, RapidGBM is expected to assist EP transient advocates, Space-based multiband astronomical Variable Objects Monitor burst advocates, and other members of the community in cross checking high-energy transients. Based on prompt emission parameter relations (e.g., Ep–Eγ,iso), it can also help identify peculiar GRBs (e.g., long-short burst, magnetar giant flare, etc.) and provide useful references (e.g., more accurate T0) for scheduling follow-up observations.

We present a systematic search for changing-look (CL) quasars at high redshift z > 0.9 by crossmatching the spectroscopic data sets from the Dark Energy Spectroscopic Instrument Data Release 1 and Sloan Digital Sky Survey Data Release 18. We identify 97 CL quasars showing significant variability in high-ionization broad emission lines, including 45 turn-on and 52 turn-off events, corresponding to a detection rate of ∼0.042%. The low rate relative to low-ionization CL quasar searches is likely due to selection and physical effects in high-ionization lines. Based on the CL quasar sample, we find that CL quasars generally exhibit lower accretion rates compared to typical quasars, with average Eddington ratios of logλEdd ∼ −1.14 in the bright state and ∼−1.39 in the dim state, compared to ∼−0.65 for typical quasars. Furthermore, while high-ionization lines in CL quasars follow the Baldwin effect on a population level, some sources can display inverse Baldwin trends. In addition, we find a positive correlation between the variability in high-ionization lines (e.g., Mg ii, C iii]) and the change in bolometric luminosity. We also estimate a characteristic rest-frame timescale of ∼3 yr for CL transitions, with no significant difference between turn-on and turn-off cases. Taken as a whole, these findings support an accretion-driven origin of the CL phenomenon, and provide new insights into the variability of high-ionization emission lines.

A novel boost converter named tri-state boost converter is introduced in this paper. According to the operation principle of the tri-state boost converter, the Euler-Lagrange model is set up. Based on the passivity-based control theory and Euler-Lagrange model, a passivity-based controller of the tri-state boost converter is designed. By damping injecting, the input current and output voltage of the tri-state boost converter can reach the desired equilibrium values rapidly. The speed of the tri-state boost converter to reach the desired equilibrium values varies when the damping values changes. The controller is simple to design and makes the tri-state boost converter having better dynamic and steady performances. The passivity-based controller proposed in the paper is proved feasible by simulation results.

Extragalactic fast X-ray transients (eFXTs) represent a rapidly growing class of high-energy phenomena, whose physical origins remain poorly understood. With its wide-field, sensitive all-sky monitoring, the Einstein Probe (EP) has greatly increased the discovery rate of eFXTs. The search and identification of the optical counterparts of eFXT are vital for understanding their classification and constraining their physical origin. Yet, a considerable fraction of eFXTs still lack secure classifications due to the absence of timely follow-up observations. We carry out a systematic search of publicly available optical survey data and transient databases (including the Zwicky Transient Facility, ZTF, and the Transient Name Server, TNS) for optical counterparts to eFXT candidates detected by EP. In this paper, we describe our ongoing program and report the first results. Specifically, we identified the eFXT EP240506a to be associated with a UV/optical counterpart, AT 2024ofs. Spectroscopy of its host galaxy with VLT yields a redshift of \\(z = 0.120 \\pm 0.002\\). By combining archival survey data with early-time multiwavelength observations, we find that the luminosity and light-curve evolution of AT~2024ofs are consistent with a core-collapse supernova origin. From detectability simulations, we estimate a local event rate density \\(\\rho_{0}=8.8^{+21.2}_{-3.9}\\ \\mathrm{yr^{-1}\\, Gpc^{-3}}\\) for EP240506a-like events, and completeness-corrected rate of about \\(36\\)--\\(78\\ \\mathrm{yr^{-1}\\ Gpc^{-3}}\\) for EP-detected X-ray transients associated with supernovae. Our results demonstrate the potential of EP to uncover prompt high-energy emission from core-collapse supernovae and underscore the critical importance of timely follow-up of future eFXT events.

The physical origin of fast radio bursts (FRBs) remains uncertain. Although multiwavelength observations have been widely conducted, only Galactic FRB 20200428D is associated with an X-ray burst from the magnetar SGR J1935+2154. Here we present multiwavelength follow-up observations of the nearby bright FRB 20250316A, including the Five-hundred-meter Aperture Spherical radio Telescope (FAST), Einstein Probe (EP) X-ray mission, Chandra X-ray Observatory, Wide Field Survey Telescope (WFST), and Space Variable Objects Monitor/Visible Telescope (SVOM/VT). The 13.08 hr FAST follow-up campaign without pulse detection requires an energy distribution flatter than those of well-known repeating FRBs, suggesting that this burst is likely a one-off event. A prompt EP follow-up and multiepoch observational campaign totaling >100 ks led to the detection of an X-ray source within the angular resolution of its Follow-up X-ray Telescope (FXT; 10″). A subsequent Chandra observation revealed this source to be offset by 7″ from the FRB position and established a 0.5–10 keV flux upper limit of 7.6 × 10−15 erg cm−2 s−1 at the FRB position, corresponding to ∼1039 erg s−1 at the 40 Mpc distance of the host galaxy NGC 4141. These results set one of the most stringent limits on X-ray emission from a nonrepeating FRB, disfavoring ultraluminous X-ray sources as counterparts of apparently one-off FRBs and offering critical insights into afterglow models. Our study suggests that an arcsecond localization of both the FRB and its potential X-ray counterpart is essential for exploring the X-ray counterpart of an FRB.

We present multiband observations and analysis of EP240801a, a low-energy, extremely soft gamma-ray burst (GRB) discovered on 2024 August 1 by the Einstein Probe (EP) satellite with a weak contemporaneous signal also detected by the Fermi Gamma-ray Burst Monitor (GBM). Optical spectroscopy of the afterglow, obtained by Gran Telescopio Canarias and Keck, identified the redshift of z = 1.6734. EP240801a exhibits a burst duration of 148 s in X-rays and 22.3 s in gamma rays, with X-rays leading by 80.61 s. Spectral lag analysis indicates that the gamma-ray signal arrived 8.3 s earlier than the X-rays. Joint spectral fitting of EP Wide-field X-ray Telescope and Fermi/GBM data yields an isotropic energy Eγ,iso=(5.57−0.50+0.54)×1051erg , a peak energy Epeak=14.90−4.71+7.08keV , and a fluence ratio S(25–50 keV)/S (50–100keV)=1.67−0.46+0.74 , classifying EP240801a as an X-ray flash (XRF). The host-galaxy continuum spectrum, inferred using Prospector, was used to correct its contribution for the observed outburst optical data. Unusual early R-band behavior and EP Follow-up X-ray Telescope observations suggest multiple components in the afterglow. Three models are considered: a two-component jet model, a forward-reverse shock model, and a forward shock model with energy injection. All three provide reasonable explanations. The two-component jet model and the energy injection model imply a relatively small initial energy and velocity of the jet in the line of sight, while the forward-reverse shock model remains typical. Under the two-component jet model, EP240801a may resemble GRB 221009A (BOAT) if the bright narrow beam is viewed on-axis. Therefore, EP240801a can be interpreted as an off-beam (narrow) jet or an intrinsically weak GRB jet. Our findings provide crucial clues for uncovering the origin of XRFs.

Extragalactic fast X-ray transients (eFXTs) represent a rapidly growing class of high-energy phenomena, whose physical origins remain poorly understood. With its wide-field, sensitive all-sky monitoring, the Einstein Probe (EP) has greatly increased the discovery rate of eFXTs. The search for and identification of the optical counterparts of eFXTs are vital for understanding their classification and constraining their physical origin. Yet, a considerable fraction of eFXTs still lack secure classifications due to the absence of timely follow-up observations. We carry out a systematic search of publicly available optical survey data and transient databases (including the Zwicky Transient Facility and the Transient Name Server) for optical counterparts to eFXT candidates detected by EP. In this paper, we describe our ongoing program and report the first results. Specifically, we identified the eFXT EP240506a to be associated with a UV/optical counterpart, AT 2024ofs. Spectroscopy of its host galaxy with the Very Large Telescope yields a redshift of z = 0.120 ± 0.002. By combining archival survey data with early-time multiwavelength observations, we find that the luminosity and light-curve evolution of AT 2024ofs are consistent with a core-collapse supernova origin. From detectability simulations, we estimate a local event rate density ρ0=8.8−3.9+21.2yr−1Gpc−3 for EP240506a-like events, and completeness-corrected rate of about 36–78 yr−1 Gpc−3 for EP-detected X-ray transients associated with supernovae. Our results demonstrate the potential of EP to uncover prompt high-energy emission from core-collapse supernovae and underscore the critical importance of timely follow-up of future eFXT events.

The gene-guided dosing strategy of warfarin generally leads to over-dose in patients at doses lower than 2 mg/kg, and only 50% of individual variability in daily stable doses can be explained, In this study, we developed a novel population pharmacokinetic （PK） model based on a warfarin dose algorithm for Han Chinese patients with valve replacement for improving the dose prediction accuracy, especially in patients with low doses. The individual pharmacokinetic （PK） parameter - apparent clearance of S- and R-warfarin （CLs） was obtained after establishing and validating the population PK model from 296 recruited patients with valve replacement. Then, the individual estimation of CLs, VKORCl genotypes, the steady-state international normalized ratio （INR） values and age were used to describe the maintenance doses by multiple linear regression for 144 steady-state patients. The newly established dosing algorithm was then validated in an independent group of 42 patients and was compared with other dosing algorithms for the accuracy and precision of prediction. The final regression model developed was as follows： Dose=-0.023×AGE＋1.834×VKORC1＋0.952×1NR＋2.156×CLs （the target INR value ranges from 1.8 to 2.5）. The validation of the algorithm in another group of 42 patients showed that the individual variation rate （71.6%） was higher than in the gene-guided dosing models. The over-estimation rate in patients with low doses （〈2 mg/kg） was lower than the other dosing methods. This novel dosing algorithm based on a population PK model improves the predictive performance of the maintenance dose of warfarin, especially for low dose （〈2 mg/d） patients.

A new Cuk converter with high step-down ratio was proposed. The operating principle and operating mode of the new Cuk converter were analyzed in detail and the EL model of the new Cuk converter was established. Based on passivity-based control theory, a passivity-based controller of the new Cuk converter was designed by the method called damping injection. The controller can enable the new Cuk converter achieve good dynamic and static performance and robustness to the load. Compared with Buck converters, the new Cuk converter has a higher step-down capability and a smaller ripple of the input current. Simulation results show that the new Cuk converter is feasible.

In order to prepare a novel hemostatic dressing for uncontrolled hemorrhage, a porous chitosan sponge was coated with self-assembled (thrombin/tannic acid)n films, which were based on hydrogen bonding interactions between thrombin and tannic acid at physiologic pH. According to the whole blood clotting test, the coated chitosan sponges showed a significantly high rate of blood clotting due to the addition of thrombin. On the other hand, the storable half-life of immobilized thrombin is extended to 66.9 days at room temperature, which is 8.5 times longer than unfixed thrombin. It is because of the immobilization effect of, not only the porous structure of chitosan sponge but also the interactions between thrombin and tannic acid. In addition, the tannic acid has similar antibacterial effect to chitosan. Therefore, it is an excellent combination of chitosan, thrombin and tannic acid. Besides, all of materials in this research have been approved by the United States Food and Drug Administration (FDA). So the chitosan-based sponge is a promising candidate dressing for uncontrolled hemorrhage due to its storable, bio-safe and highly effective hemostatic properties.