A Search for Radio Pulsars in Supernova Remnants Using FAST with One Pulsar Discovered

We report the results of a search for radio pulsars in five supernova remnants(SNRs)with the FAST telescope.The observations were made using the 19-beam receiver in“snapshot”mode.The integration time for each pointing was 10 min.We discovered a new pulsar,PSR J1845–0306,which has a spin period of 983.6 ms and a dispersion measure of 444.6±2.0 cm^(−3)·pc,in observations of SNR G29.6+0.1.To judge the association between the pulsar and the SNR,further verification is needed.We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3.No pulsars were detected in the observations of the other three SNRs.

The control of astronomical cycles on lacustrine fine-grained event Sedimentation——A case study of the Chunshang sub-member of the upper Es_(4) in the Dongying Sag

Fine-grained lacustrine sedimentation controlled by astronomical cycles remains a research weakness in sedimentology studies,as most studies have concentrated on how astronomical cycles affect the normal lacustrine fine-grained sedimentation,but how they affect the lacustrine fine-grained event sedimen-tation has been rarely studied.Therefore,this work researched the characteristics of event sedimentation by systematically observing the cores from 30 cored wells in the Shahejie Formation of the Dongying Sag at a depth of over 1800 m,with more than 4000 thin sections being authenticated and over 1000 whole rocks being analyzed by X-ray diffraction(XRD).The research object was the Chunshang Sub-member of Upper Es_(4) in the Fanye 1 well,as it had the most comprehensive analysis data and underwent the most continuous coring.We divided astronomical cycles into different orders and made corresponding curves using the gamma-ray(GR)curve,spectral analysis,power spectrum estimation,and module extreme values,there were 6 long eccentricity periods,22 short eccentricity periods,65.5 obliquity cycles,and 110.5 precession cycles in this sub-member.On this basis,this study analyzed the control of astronomical cycles on the lacustrine fine-grained event sedimentation,and the research shows deposits were developed by slide-slump,turbidities,hyperpycnites,and tempestites in the Chunshang Sub-member of the Upper Es_(4),with higher long eccentricity,the monsoon climate contributes to the formation of storm currents,while with lower long eccentricity,the surface deposits are severely eroded by rivers and rainfalls,thus developing the slide-slump,turbidities,and hyperpycnites.The relationship between the lacustrine fine-grained event sedimentation and astronomical cycles was studied in this case study,which can promote research on fine-grained sedimentary rocks in genetic dynamics and boost the theoretical and disciplinary development in fine-grained sedimentology.

Clinical significance of serum oxidative stress and serum uric acid levels before surgery for hepatitis B-related liver cancer

BACKGROUND The incidence and mortality of liver cancer are among the highest of all malignant tumors in China.The high recurrence rate after conventional hepatectomy is worrying.There is a lack of effective prognostic indicators for liver cancer.AIM To explore the clinical significance of preoperative serum oxidative stress and serum uric acid(UA)levels in hepatitis B-related liver cancer.METHODS The medical records of 110 hepatitis B-related liver cancer patients who under-went hepatectomy in Gansu Provincial Hospital were retrospectively analyzed.Recurrence in patients within 3 years after surgery was determined.The logistic regression model and Pearson or Spearman correlation were used to analyze the correlation between oxidative stress level and UA,and the recurrence of hepatitis B-related liver cancer.RESULTS Compared with the non-recurrence group,the levels of superoxide dismutase(SOD)and glutathione(GSH)in the recurrence group were lower and the levels of malondialdehyde(MDA)and UA were higher(all P<0.05).UA,SOD,MDA,and GSH were risk factors for postoperative recurrence in hepatitis B-related liver cancer patients(P<0.05).UA was positively correlated with MDA(r=0.395,P<0.001)and negatively correlated with GSH(r=-0.204,P=0.032).The area under the receiver operating characteristic curve(AUC)of SOD,MDA,GSH,and UA in predicting the prognosis was 0.276,0.910,0.199,and 0.784,respectively(all P<0.001).CONCLUSION The preoperative serum SOD,GSH,MDA,and UA levels had significant predictive effects on postoperative recurrence of hepatitis B-related liver cancer.

人胚胎干细胞来源的成纤维细胞支持无动物源污染条件下的人精原干细胞生长

精原干细胞在人出生后可以连续分裂以支持精子形成，将遗传信息传递给下一代。在本文中，我们成功地从睾丸组织中分离并鉴别人精原干细胞的一种新方法，并在人胚胎干细胞来源的成纤维细胞上扩增人精原干细胞。在这种人胚胎干细胞来源的成纤维细胞上可维持大量的人精原干细胞并且在组合生长因子，特别是胶质细胞来源的神经生长因子存在的条件下扩增至少2个月。细胞表面标志分析显示这些精原干细胞具有高水平的碱性磷酸酶的表达并保持了高水平的胚胎特异阶段抗原SSEA-1，OCT4和CD49f的表达。用逆转录PCR反应检测出OCT4，SOX3，STRA8基因的表达。这些数据清晰地表明运用人胚胎干细胞来源的成纤维细胞来支持人精原干细胞的一个新的策略，并排除了异源物种的污染。这个系统提供了新的机会去了解干细胞巢对于控制精原干细胞自我更新的调节机制，并将对于精原干细胞潜在的临床应用提供有用的精原干细胞。

The Multiple Images of the Plasma Lensing FRB

We investigate the formation of multiple images as the radio signals from fast radio bursts(FRBs)pass through the plane of a plasma clump.The exponential model for the plasma clump is adopted to analyze the properties of the multiple images.By comparing with the classical dispersion relations,we find that one image has exhibited specific inverse properties to others,such as their delay times at high frequency is higher than that at low frequency,owing to the lensing effects of the plasma clump.We demonstrate that these inverse effects should be observable in some repeating FRBs.Our results predict deviation in the estimated dispersion measure(DM)across multiple images,consistent with the observations of FRB 121102 and FRB 180916.J0158+65.If other plasma lenses have effects similar to an exponential lens,we find that they should also give rise to a similar dispersion relation in the multiple images.For some repeating FRBs,analysis of the differences in time delay and in DM between multiple images at different frequencies can serve as a method to reveal the plasma distribution.

The r-mode instability windows of strange stars

With the constraint from gravitational wave emission of a binary merger system(GW170817)and two-solar-mass pulsar observations, we investigate the r-mode instability windows of strange stars with unpaired and color-flavor-locked phase strange quark matter. Shear viscosities due to surface rubbing and electron-electron scattering are taken into account in this work. The results show that the effects of the equation of state of unpaired strange quark matter are only dominant at low temperature, but do not have significant effects on strange stars in the color-flavor-locked phase. A color-flavor-locked phase strange star,which is surrounded by an insulating nuclear crust, seems to be consistent with observational data of young pulsars. We find that an additional enhanced dissipation mechanisms might exist in SAX J1808.4–3658.Fast spinning young pulsar PSR J0537–6910 is a primary source for detecting gravitational waves from a rotating strange star, and young pulsars might be strange stars with color-flavor-locked phase strange quark matter.

Targeted Search for Fast Radio Bursts with Nanshan 26m Radio Telescope

Fast radio bursts(FRBs)are radio transients that are bright and have short duration,with their physical mechanism not being fully understood.We conducted a targeted search for bursts from FRB 20201124A between 2021 June 2and July 20.High time-resolution data were collected for 104.5 hr using the ROACH2-based digital backend.We introduce the details of our FRB search pipeline which is based on HEIMDALL and FETCH.Testing of the injected mock FRBs search could help us better understand the performance of the pipelines,and improve the search algorithms and classifiers.To study the efficiency of our pipeline,5000 mock FRBs were injected into the data and searched using the pipeline.The results of the mock FRB search show that our pipeline can recover almost all(?90%)the injected mock FRBs above a signal-to-noise ratio(S/N)threshold of 15,and the performance is still acceptable(?80%)for injected S/Ns from 10 to 15.The recovery fraction displays relations with S/N,dispersion measure and pulse width.No bursts were detected from FRB 20201124A in the middle of 2021.The non-detection of FRB 20201124A may be due to its quiet phase window or no emission above the threshold of the Nanshan telescope.

Polyether-polyester and HMDI Based Polyurethanes:Effect of PLLA Content on Structure and Property

Thermoplastic poly(ether-ester-urethane)s were synthesized from poly(L-lactide) diols (PLLA diols), polytetrahydrofuran diol (PTMG diols), 4,4'-dicyclohexylmethane diisocyanate (HMDI), and 1,4-butanediol (BDO) by a two-step reaction, and the morphology and property of the resultant TPU could be adjusted by varying the PLLA contents. The soft segment was composed of PLLA and PTMG diols. By controlling the percentage of PLLA in the soft segment, the glass transition temperature and mechanical properties of the polyurethanes could be regulated. Based on the FTIR spectrum, we found that two kinds of hydrogen bonding existed individually in soft matrix and hard domain. The hydrogen bonding in soft matrix was unstable, which could be destroyed during elongation. With in situ stretching WAXS and SAXS experiments, we found that the PLLA crystal was destroyed and the PLLA domain oriented along the stretch direction. Finally, we proposed a schematic model to illustrate the microstructures of these elastomers before and after stretch.