Based on the concept of translational medicine in the exploration and practice of teaching reform of pathophysiology

Objective: To investigate the application of the teaching mode in pathophysiology, based on the thought of translational medicine and combined basic medicine with clinical medicine. Methods: Choosing the five-year period medical undergraduates in our university, who were enrolled in the year of 2012, through developing comprehensive case-based teaching (CCBT) in large class teaching, having case-problem based learning (CPBL) in small class teaching, and carrying out comprehensive open experiments during the experiment teaching, the pathophysiology teachers participated in clinical (internal medicine) practice, to apply the concept of translational medicine into Pathophysiology teaching reform, setting up a teaching mode, which was based on the thought of translational medicine and combined basic medicine with clinical medicine. Results: This model of education further stimulated students’ interest in study, enlightened their creative thought, enhanced the initiative of students greatly, raised students' ability to think and solve problems independently. At the same time, it improved the teachers' teaching level, and made this curriculum serving as a bridge between basic medicine and clinical medicine. Conclusion: The pedagogical reform of pathophysiology, which was based on the idea of translational medicine, improved educational effect and was worthy to be applied further

Effect of ligustrazine injection on the change of oxidative stress system during renal ischemia reperfusion injury in rabbits

目的  通过由兔肾脏缺血/再灌注损伤（IRI）导致的氧化应激体系中的变化，研究中药川芎嗪对IRI干预下的作用机制。方法  建立持续性阻断兔双侧肾动脉血流1h，再灌注5h的肾IRI动物模型。日本大耳兔32只，随机分成3组（n=10）：假手术组(sham，S组)，缺血/再灌注组(ischemia-reperfusion，IR组)，川芎嗪干预缺血/再灌注组（ligustrazine+ ischemia-reperfusion，LZ组），另外两只作为补充实验中意外死亡之用。于缺血前、缺血1h、再灌注1h、3h和5h依次经颈总动脉抽血用以检测超氧化物歧化酶（SOD）活力、黄嘌呤氧化酶（XO）活力以及丙二醛（MDA）含量。在实验结束后取兔肾组织依次检测SOD、XO活力以及MDA含量，并对其进行电镜观察。结果  随着肾缺血和再灌注时间的增加，IR组和LZ组血浆中的XO活力和MDA含量逐渐呈上升趋势，但同时间点LZ组较于IR组明显降低（均P<0.01）；SOD活力随着肾缺血和再灌注时间的增加而逐渐呈下降趋势，但同时间点下，LZ组较于IR组均明显偏高（均P<0.01）。IR组和LZ组相较于S组，肾组织XO活力、MDA含量均明显升高，SOD活力均明显降低（均P<0.01）；而LZ组肾组织中的XO活力、MDA含量均显著低于IR组，SOD活力均显著高于IR组，差异有非常显著性（均P<0.01），LZ组肾组织细胞的超微结构异常改变较IR组显著减轻。结论  川芎嗪能够使氧自由基水平降低，氧化应激损伤减轻，具有保护肾缺血/再灌注损伤的作用。Objective: To investigate the change of oxidative stress system during renal ischemia-reperfusion injury, and to study the mechanism of Ligustrazine on IRI under the intervention. Methods: Establish the IRI animal model by persistent blocking rabbits’ bilateral renal artery blood flow for 1 hour, then reperfusion for another 5 hours. Japanese big ear rabbits, 32, were randomly divided into three groups (n=10): sham operation group (group S), ischemia/reperfusion group (group IR), the effect of ligustrazine on ischemia/ reperfusion group (LZ group), the other two being added in the experiment for accidental death. In 1 hour before ischemia, ischemia, reperfusion 1h, 3h and 5h in turn to check the enzyme activity of superoxide dismutase (SOD), xanthine oxidase (XO) and the content of malondialdehyde (MDA) by getting the blood from common carotid artery. At the end of the experiment, the rabbit’s kidney was used to check the enzyme activity of XO, SOD and the content of MDA, then to observe the morphological changes under the electron microscopy. Results: With the increase of renal ischemia and reperfusion time, XO activity and MDA content of IR group and LZ group in plasma gradually up, they were significantly lower in LZ group than in IR group at same time point (all P<0.01), the activity of SOD in plasma was shown a time-dependent decline in both IR group and LZ group, whereas it was significant higher in LZ group compared with IR group at same time point during ischemia reperfusion (all P<0.01). SOD activity gradually decreased with the increase of renal ischemia and reperfusion time, but at the same time point, LZ group compared with IR group were significantly higher (P<0.01), however, for LZ group, as compared with IR group, activity of XO, content of MDA were increased remarkably while activity of SOD was decreased significantly in kidney tissue (all P<0.01) the abnormal changes of ultrastructure were mitigated significantly. Conclusion: Ligustrazine may attenuate renal ischemia-reperfusion injury by dropping oxygen free radical generation and enhancing oxygen free radical scavenge so that it can antagonize oxidative stress

FAST observations of an extremely active episode of FRB 20201124A: IV. Spin Period Search

We report the properties of more than 800 bursts detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio telescope (FAST) during an extremely active episode on UTC September 25th-28th, 2021 in a series of four papers. In this fourth paper of the series, we present a systematic search of the spin period and linear acceleration of the source object from both 996 individual pulse peaks and the dedispersed time series. No credible spin period was found from this data set. We rule out the presence of significant periodicity in the range between 1 ms to 100 s with a pulse duty cycle $< 0.49\pm0.08$ (when the profile is defined by a von-Mises function, not a boxcar function) and linear acceleration up to $300$ m s$^{-2}$ in each of the four one-hour observing sessions, and up to $0.6$ m s$^{-2}$ in all 4 days. These searches contest theoretical scenarios involving a 1 ms to 100 s isolated magnetar/pulsar with surface magnetic field $<10^{15}$ G and a small duty cycle (such as in a polar-cap emission mode) or a pulsar with a companion star or black hole up to 100 M$_{\rm \odot}$ and $P_b>10$ hours. We also perform a periodicity search of the fine structures and identify 53 unrelated millisecond-timescale "periods" in multi-components with the highest significance of 3.9 $\sigma$. The "periods" recovered from the fine structures are neither consistent nor harmonically related. Thus they are not likely to come from a spin period. We caution against claiming spin periodicity with significance below $\sim$ 4 $\sigma$ with multi-components from one-off FRBs. We discuss the implications of our results and the possible connections between FRB multi-components and pulsar micro-structures.Comment: Accepted by Research in Astronomy and Astrophysics (RAA

FAST observations of an extremely active episode of FRB 20201124A: III. Polarimetry

As the third paper in the multiple-part series, we report the statistical properties of radio bursts detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio telescope (FAST) during an extremely active episode between the 25th and the 28th of September 2021 (UT). We focus on the polarisation properties of 536 bright bursts with $\mathrm{S/N}>50$. We found that the Faraday rotation measures (RMs) monotonically dropped from $-579 \ {\rm rad \ m^{-2}}$ to $-605 \ {\rm rad \ m^{-2}}$ in the 4-day window. The RM values were compatible with the values ($-300$ to $-900\ {\rm rad \ m^{-2}}$ ) reported 4 month ago (Xu et al. 2022). However, the RM evolution rate in the current observation window was at least an order of magnitude smaller than the one ($\sim 500\ {\rm rad \ m^{-2}\, day^{-1}}$) previously reported during the rapid RM-variation phase, but is still higher than the one ($\le 1\ {\rm rad \ m^{-2} day^{-1}}$) during the later RM no-evolution phase. The bursts of FRB 20201124A were highly polarised with the total degree of polarisation (circular plus linear) greater than 90polarisation position angles (PAs), degree of linear polarisation ($L/I$), and degree of circular polarisation ($V/I$) can be characterised with unimodal distribution functions. During the observation window, the distributions became wider with time, i.e. with larger scatter, but the centroids of the distribution functions remained nearly constant. For individual bursts, significant PA variations (confidence level 5-$\sigma$) were observed in 33% of all bursts. The polarisation of single pulses seems to follow certain complex trajectories on the Poincar\'e sphere, which may shed light on the radiation mechanism at the source or the plasma properties along the path of FRB propagation.Comment: 25 pages, 16 figures. Accepted by Research in Astronomy and Astrophysics (RAA

Corrigendum to: The TianQin project: current progress on science and technology

In the originally published version, this manuscript included an error related to indicating the corresponding author within the author list. This has now been corrected online to reflect the fact that author Jun Luo is the corresponding author of the article