Subjects: Pharmaceutical Science >> Structural Biology submitted time 2024-02-29
Abstract： Succinic acid, a tricarboxylic acid (TCA) cycle intermediate, significantly influences mitochondrial reactive oxygen species homeostasis through the G protein-coupled succinate receptor (SUCR1, also called GPR91), linking it to various physiological and pathological processes. Despite SUCR1’s pivotal role in mediating effects leading to liver fibrosis, hypertension, angiogenesis, inflammation, and offering a therapeutic target for multiple diseases, its activation mechanism by diverse ligands and interaction with downwards G protein remains poorly understood. This study presents the cryo-electron microscopy (cryo-EM) structures of SUCR1 in complex with inhibitory G protein (Gi) bound to succinic acid, maleic acid, and compound 31, a high-affinity agonist. These structures elucidate the distinct ligand binding modes, uncover the activation signal cascade, and detail the G protein coupling mechanism of SUCR1. Our findings provide a comprehensive structural basis for SUCR1 activation, paving the way for structure-based drug design aimed at SUCR1-related pathologies.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-02-29
Yang Jiao
Jie Liu
Pei-Xiong Zhao
Li-Hua Mo
Jin-Hu Yang
Yu-Zhu Liu
Ya-Nan Yin
Liang Wang
Qi-Yu Chen
Xiao-Yu Yan
Shi-Wei Zhao
Bo Li
You-Mei Sun
Abstract： The 28nm process has a high cost-performance ratio and has gradually become the standard for the field
of radiation-hardened devices. However, owing to the minimum physical gate length of only 35nm, the physical
area of a standard 6T SRAM unit is approximately 0.16 μm2, resulting in a significant enhancement of
multi-cell charge-sharing effects. Multiple-cell upsets (MCUs) have become the primary physical mechanism
behind single-event upsets (SEUs) in advanced nanometer node devices. The range of ionization track effects
increases with higher ion energies, and spacecraft in orbit primarily experience SEUs caused by high-energy
ions. However, ground accelerator experiments have mainly obtained low-energy ion irradiation data. Therefore,
the impact of ion energy on the SEU cross-section, charge collection mechanisms, and MCU patterns and
quantities in advanced nanometer devices remains unclear. In this study, based on the experimental platform
of the Heavy Ion Research Facility in Lanzhou (HIRFL), low- and high-energy heavy-ion beams were used
to study the SEUs of 28nm SRAM devices. The influence of ion energy on the charge collection processes
of small-sensitive-volume devices, MCU patterns, and upset cross-sections was obtained, and the applicable
range of the inverse-cosine law was clarified. The findings of this study are an important guide for the accurate
evaluation of SEUs in advanced nanometer devices and for the development of radiation-hardening techniques.
Subjects: Psychology >> Applied Psychology submitted time 2024-02-29
Abstract： HPV vaccination can not only effectively prevent the development of cervical cancer and its precancerous lesions, but also prevent other parts of the disease caused by HPV infection. However, the vaccination situation in China is not optimistic, and many young people are hesitant to get the HPV vaccine. Based on the planning theory model, this study aims to explore the influencing factors of HPV vaccination intention, compile a questionnaire with good reliability and validity to evaluate the importance of influencing factors of HPV vaccination intention, and explore the importance degree of influencing factors of different vaccination intention. In experiment 1, this study explored the influencing factors of individual HPV vaccination intention through semi-structured interview method, and obtained 25 influencing factors such as vaccine safety, vaccine effectiveness, vaccination convenience, professionalism, conformity and data. In experiment 2, through exploratory factor analysis, confirmatory factor analysis and reliability and validity test, a 17-question, 4-dimensional questionnaire was constructed to evaluate the importance of factors influencing HPV vaccination intention. Among them, confirmatory factor analysis supported the 4-factor model (χ²/df<3, RMR=0.059, RMSEA=0.054, GFI=0.928, TLI=0.914, IFI=0.929), showing good model fit. The Cronbach’s α coefficient of the questionnaire was 0.853, and the retest reliability at a 4-week interval was 0.804. It shows that our questionnaire has good reliability and validity. In addition, there are significant differences in the evaluation of the importance of different influencing factors, and there are also significant differences in the evaluation of the importance of factors among individuals with or without a family history of cancer and different levels of education. This study will provide valuable insights into vaccination promotion strategies and provide scientific basis and reference for developing targeted approaches.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Applied Psychology Subjects: Computer Science >> Computer Application Technology submitted time 2024-02-29
Abstract： Objective With the development of network big data and machine learning, more and more studies starting to combine text analysis and machine learning algorithms to predict individual satisfaction. In the studies focused on building life satisfaction prediction models, it is often difficult to obtain large amounts of valid and labeled data. This study aims at solving this problem using data augmentation and optimizing the prediction model of life satisfaction. Method Using 357 life status descriptions annotated by self-rating life satisfaction scale scores as original text data. After preprocessing using DLUT-Emotionontology, EAD and back-translation method was applied and the prediction model was built using traditional machine learning algorithms. Results Results showed that (1) the prediction accuracy was largely enhanced after using the adapted version of DLUT-Emotionontology; (2) only linear regression model was enhanced after data augmentation; (3) rigid regression model showed the greatest prediction accuracy when trained by original data (r = 0.4131). Conclusion The improvement of feature extraction accuracy can optimize the current life satisfaction prediction model, but the text data augmentation methods, such as back translation and EDA may not be applicable for the life satisfaction prediction model based on word frequency.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Social Psychology submitted time 2024-02-28
Abstract： Post of Wanna back to senior high and take a break for days goes virus on social media. To study nostalgia for senior high in college students, we use a questionnaire and innovatively combines two interdisciplinary methods, statistical analysis and corpus analysis. We raise a method for calculating the composite nostalgia score of college students, and draws 3 conclusions: (1) college students’ nostalgia is higher among males than females; (2) freshmen are less nostalgic than other grades; (3) except for the National I Paper region, the higher the overall level of high school education, the more nostalgic students are. This study also proposes 8 hypotheses for further research and reference to multiple groups. The shortcomings of this study lie in the part of the questionnaire design and the way of data analysis that is not reasonable, and the part of the small probability event that is not correctly viewed.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Other Disciplines of Nuclear Science Subjects: Physics >> Nuclear Physics submitted time 2024-02-28
Lei Peng
Shangming Chen
Jingyi Shi
Yongjie Sun
Yifei Liu
Yinzhong Shen
Hongya He
Huijuan Wang
Jie Tian
Abstract： Ferritic/martensitic (F/M) steel is widely used as a structural material in thermal and nuclear power plants. However, it is susceptible to intergranular damage, which is a critical issue, under service conditions. In this study, to improve the resistance to intergranular damage of F/M steel, a thermomechanical process (TMP) was employed to achieve a grain boundary engineering (GBE) microstructure in F/M steel P92. The TMP, including cold-rolling thickness reduction of 6%, 9%, and 12%, followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min, was applied to the as-received (AR) P92 steel. The prior austenite grain (PAG) size, prior austenite grain boundary character distribution (GBCD), and connectivity of prior austenite grain boundaries (PAGBs) were investigated. Compared to the AR specimen, the PAG size did not change significantly. The fraction of coincident site lattice boundaries (CSLBs, 3 ≤ Σ ≤ 29) and Σ3n boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction ratio. The PAGB connectivity of the 6% deformed specimen slightly deteriorated compared with that of the AR specimen. Moreover, potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs, indicating that the TMP, which involves low deformation, could enhance the intergranular damage resistance.
Subjects: Mathematics >> Geometry and Topology submitted time 2024-02-28
Abstract： In this paper, we study biharmonic Riemannian submersions $ pi:M^2 times r to (N^2,h)$ from a product manifold onto a surface and obtain some local characterizations of such biharmonic maps. Our results show that when the target surface is flat, then a proper biharmonic Riemannian submersion $ pi:M^2 times r to (N^2,h)$ is locally a projection of a special twisted product, and when the target surface is non-flat, $ pi$ is locally a special map between two warped product spaces with a warping function that solves a single ODE. As a by-product, we also prove that there is a unique proper biharmonic Riemannian submersion $H^2 times r to r^2$ given by the projection of a warped product.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-02-28
Xu Hanghua
Liu Longxiang
Zhang Yue
Hao Zirui
Yang Yuxuang
Jin Sheng
Chen Kaijie
Li Zhicai
Jiao Pu
Zhou Mengdie
Wang Zhenwei
Wang Hongwei
Fan Gongtao
Abstract： : Introduces the construction and trial operation of Shanghai Laser Electron Gamma Source (SLEGS) beamline station, one
of the Shanghai light source(SSRF) projects II, which can carry out basic research on nuclear physics and nuclear astrophysics, and
carry out applied research such as gamma irradiation, gamma imaging and gamma activation at SLEGS gamma source. The SLEGS
beamline station passed the process acceptance in December 2021, entered the trial operation stage in October 2022, and have open
to users in September 2023. SLEGS is the first in the world to use the continuous collision angle mode to change the energy of the
gamma beam, with the best energy scanning accuracy, flow intensity density and efficient energy regulation ability. In the trial
operation stage, the SLEGS beamline station focused on solving the problem of online monitoring of gamma beam energy spectrum
and flow intensity, mainly completed the experimental methodology research of optical neutron cross-section measurement by flat
efficiency spectrometer (FED), and carried out the expansion and research of application platforms such as gamma imaging, gamma
activation, and positron source generation. With the development of inverse Compton scattering techniques, short-pulse,
high-polarization, high-throughput, and miniaturized laser Compton scattering light sources will usher in better development
opportunities in the future, and will play an important role in nuclear physics, astrophysics, particle physics, polarization physics, as
well as aerospace, medical testing, energy development and other gamma source application research fields.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： We tested a new model of CMOS detector manufactured by the Gpixel Inc, for potential space astronomical application. In laboratory, we obtain some bias images under the typical application environment. In these bias images, clear random row noise pattern is observed. The row noise also contains some characteristic spatial frequencies. We quantitatively estimated the impact of this feature to photometric measurements, by making simulated images. We compared different bias noise types under strict parameter control. The result shows the row noise will significantly deteriorate the photometric accuracy. It effectively increases the readout noise by a factor of 2–10. However, if it is properly removed, the image quality and photometric accuracy will be significantly improved.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： The scattered stray light of a coronagraph is a type of stray light that is generated by the objective lens as its surface defects are irradiated by sunlight. The defects mainly include dust and blemishes on the lens surface, microroughness of the lens surface, and impurity and inhomogeneity of the glass. Unlike the other types of relatively stable defects introduced when the objective lens is being manufactured, the scattered stray light caused by dusts on the lens surface is difficult to quantify accurately due to the disorder and randomness of the dust accumulation. The contribution of this type of stray light to the overall stray light level is difficult to determine through simulations and experiments. This can result in continuous deterioration of the stray light level of a coronagraph and thus affect the observation capabilities of the instrument. To solve this issue, through analyzing the forming mechanism of scattered stray light and ghost image generated by the inner-occulted coronagraph, we propose a novel method to monitor the scattered stray light from dusts by utilizing different stray light correlation coefficients. In this method, we first simulate and measure the level of stray light from the ghost image of the objective lens, and then determine the flux ratio of scattered light and ghost image on the conjugate plane. Although the flux ratio varies with the accumulation of dusts on the lens surface, it remains constant on the image plane. Therefore, the level of dust scattering light on the image plane can be obtained by using this ratio together with the level of ghost image stray light. The accuracy of this method has been validated in a laboratory by applying the objective lens with numerous surface cleanliness levels.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： The equilibrium configuration of a solid strange star in the final inspiral phase with another compact object is generally discussed, and the starquake-related issue is revisited, for a special purpose to understand the precursor emission of binary compact star merger events (e.g., that of GRB211211A). As the binary system inspirals inward due to gravitational wave radiation, the ellipticity of the solid strangeon star increases due to the growing tidal field of its compact companion. Elastic energy is hence accumulated during the inspiral stage which might trigger a starquake before the merger when the energy exceeds a critical value. The energy released during such starquakes is calculated and compared to the precursor observation of GRB211211A. The result shows that the energy might be insufficient for binary strangeon-star case unless the entire solid strangeon star shatters, and hence favors a black hole-strangeon star scenario for GRB211211A. The timescale of the precursor as well as the frequency of the observed quasi-periodic-oscillation have also been discussed in the starquake model.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： The γ-ray emitting compact symmetric objects (CSOs) PKS 1718–649, NGC 3894, and TXS 0128+554 are lobe-dominated in the radio emission. In order to investigate their γ-ray radiation properties, we analyze the ∼14 yr Fermi/LAT observation data of the three CSOs. They all show the low luminosity (1041–1043 erg s−1) and no significant variability in the γ-ray band. Their γ-ray average spectra can be well fitted by a power-law function. These properties of γ-rays are clearly different from the γ-ray emitting CSOs CTD 135 and PKS 1413+135, for which the γ-rays are produced by a restarted aligned jet. In the Lγ − Γγ plane, the three CSOs are also located at the region occupied by radio galaxies (RGs) while CTD 135 and PKS 1413+135 display a similar feature to blazars. Together with a similar radio emission property to γ-ray emitting RGs Cen A and Fornax A, we speculate that the γ-rays of the three CSOs stem from their extended mini-lobes. The broadband spectral energy distributions of the three CSOs can be well explained by the two-zone leptonic model, where their γ-rays are produced by the inverse Compton process of the relativistic electrons in extended regions. By extrapolating the observed Fermi/LAT spectra to the very high energy band, we find that TXS 0128+554 among the three CSOs may be detected by the Cherenkov Telescope Array in the future.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： GRB 200612A could be classified as an ultralong gamma-ray burst due to its prompt emission lasting up to ∼1020 s and the true timescale of the central engine activity tburst ≥ 4 × 104 s. The late X-ray light curve with a decay index of α = 7.53 is steeper than the steepest possible decay from an external shock model. We propose that this X-ray afterglow can be driven by dipolar radiation from the magnetar spindown during its early stage, while the magnetar collapsed into the black hole before its spindown, resulting in a very steep decay of the late X-ray light curve. The optical data show that the light curve is still rising after 1.1 ks, suggesting a late onset. We show that GRB 200612A's optical afterglow light curve is fitted with the forward shock model by Gaussian structured off-axis jet. This is a special case among GRBs, as it may be an ultralong gamma-ray burst powered by a magnetar in an off-axis observation scenario.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： This paper explores the correlation between the fractional variation of the ionizing continuum and C iv broad absorption lines (BALs) with different ionization levels. Our results reveal anti-correlations between fractional variation of the continuum and fractional equivalency width (EW) variation of the C iv BALs without Al iii BAL/mini-BALs at corresponding velocities, providing evidence for the widespread influence of the ionizing continuum variability on the variation of HiBALs. Conversely, for C iv BALs accompanied by Al iii BAL/mini-BALs (LoBAL groups), no significant correction is detected. The absence of such a correlation does not rule out the possibility that variations in these low-ionization lines are caused by ionizing continuum variability, but rather suggests the influence of BAL saturation to some extent. This saturation effect is reflected in the distribution of the fractional EW variation, where the C iv BAL group accompanied by Al iii BAL has a smaller standard deviation for the best-fitting Gaussian component than the two BAL groups without Al iii BAL. However, the distribution of fractional variation of their continuum does not show any significant difference. Besides the saturation influence, another potential explanation for the lack of correlations in the LoBAL groups may be the effects of other variability mechanisms besides the ionization change, such as clouds transiting across the line of sight.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： We analyze electron acceleration by a large-scale electric field E in a collisional hydrogen plasma under the solar flare coronal conditions based on approaches proposed by Dreicer and Spitzer for the dynamic friction force of electrons. The Dreicer electric field EDr is determined as a critical electric field at which the entire electron population runs away. Two regimes of strong (E ≲ EDr) and weak (E ≪ EDr) electric field are discussed. It is shown that the commonly used formal definition of the Dreicer field leads to an overestimation of its value by about five times. The critical velocity at which the electrons of the "tail" of the Maxwell distribution become runaway under the action of the sub-Dreiser electric fields turns out to be underestimated by times in some works because the Coulomb collisions between runaway and thermal electrons are not taken into account. The electron acceleration by sub-Dreicer electric fields generated in the solar corona faces difficulties.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Remote-sensing measurements indicate that heavy ions in the corona undergo an anisotropic and mass-charge dependent energization. A popular explanation to this phenomenon is the damping of the Alfvén/ion cyclotron waves. In this paper, we propose that the ion beam instability can be an important source of the Alfvén/ion cyclotron waves, and we study the excitation of the ion beam instability in the corona at the heliocentric distance ∼3R⊙ and the corresponding energy transfer process therein based on plasma kinetic theory. The results indicate that the existence of the motionless heavy ions inhibits the ion beam instability. However, the anisotropic beams of heavy ions promote the excitation of the ion beam instability. Besides, the existence of α beams can provide a second energy source for exciting beam instability. However, when both the proton beam and the α beam reach the instability excitation threshold, the proton beam driven instability excites preferentially. Moreover, the excitation threshold of the Alfvén/ion cyclotron instability driven by ion beam is of the local Alfvén speed or even less in the corona.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： We conduct a statistical analysis of the hardness ratio (HR) for bright sources in the 4 yr Galactic Plane Scanning Survey catalog of Insight-HXMT. Depending on the stable (variable) flux Fs (Fv) or spectrum Ss(Sv) of each source, the bright sources are classified into three groups: Fv&Sv, Fv&Ss, and Fs&Ss. Our study of the HR characteristics in different types of sources reveals that accretion-powered neutron star (NS) low-mass X-ray binaries (LMXBs) exhibit softer energy spectra than NS high-mass X-ray binaries (HMXBs), but harder energy spectra than black hole binaries in most cases. This difference is probably due to their different magnetic field strengths. Additionally, Fv&Sv LMXBs tend to be harder than Fv&Ss LMXBs below 7 keV, while the opposite is true for HMXBs. Our results suggest that LMXBs may dominate unclassified sources, and NS binaries are likely to be the primary type of X-ray binaries with ambiguous compact stars. By comparing the HR of transient sources in their outburst and low-flux states, it is found that the averaged HR of four sources in the two states are roughly comparable within uncertainties. We also investigate the spatial properties of the three groups and find that Fv&Sv sources are mainly located in the longitude of −20° < l < 9°, Fv&Ss sources cross the Galactic Plane, and Fs&Ss sources are predominantly concentrated in 19° < l < 42°. In addition, analyzing the HR spatial distributions shows the absorption of soft X-rays (primarily below 2 keV) in the Galactic Plane.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： In this present study, we have analyzed different types of X-ray solar flares (C, M, and X classes) coming out from different classes of sunspot groups (SSGs). The data which we have taken under this study cover the duration of 24 yr from 1996 to 2019. During this, we observed a total of 15015 flares (8417 in SC-23 and 6598 in SC-24) emitted from a total of 33780 active regions (21746 in SC-23 and 12034 in SC-24) with sunspot only. We defined the flaring potential or flare-production potential as the ratio of the total number of flares produced from a particular type of SSG to the total number of the same-class SSGs observed on the solar surface. Here we studied yearly changes in the flaring potential of different McIntosh class groups of sunspots in different phases of SC-23 and 24. In addition, we investigated yearly variations in the potential of producing flares by different SSGs (A, B, C, D, E, F, and H) during different phases (ascending, maximum, descending, and minimum) of SC-23 and 24. These are our findings: (1) D, E, and F SSGs have the potential of producing flares ≥8 times greater than A, B, C and H SSGs; (2) The larger and more complex D, E, and F SSGs produced nearly 80% of flares in SC-23 and 24; (3) The A, B, C and H SSGs, which are smaller and simpler, produced only 20% of flares in SC-23 and 24; (4) The biggest and most complex SSGs of F-class have flaring potential 1.996 and 3.443 per SSG in SC-23 and 24, respectively. (5) The potential for producing flares in each SSG is higher in SC-24 than in SC-23, although SC-24 is a weaker cycle than SC-23. (6) The alterations in the number of flares (C+M+X) show different time profiles than the alterations in sunspot numbers during SC-23 and 24, with several peaks. (7) The SSGs of C, D, E, and H-class have the highest flaring potential in the descending phase of both SC-23 and 24. (8) F-class SSGs have the highest flaring potential in the descending phase of SC-23 but also in the maximum phase of SC-24.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： The Gaia DR3 parallax approach was used to estimate the absolute parameters of 2375 δ Scuti stars from the ASAS catalog. The selected stars have a variety of observational characteristics, with a higher than 80% probability of being δ Scuti stars. We have displayed all the stars in the Hertzsprung–Russell diagram along with the δ Scuti instability strip, the Zero Age Main Sequence and the Terminal Age Main Sequence. Then, we determined which fundamental and overtone modes each star belongs to using pulsation constant (Q) calculations. In addition, we evaluated the parameters in the Q calculation equation using three machine learning methods, which showed that surface gravity and temperature have the greatest effect on its calculation. The Period–Luminosity (P-L) relationship of the δ Scuti stars was also revisited. Eventually, using least squares linear regression, we made four linear fits for fundamental and overtone modes and updated their relationships.
Subjects: Astronomy >> Astrophysical processes submitted time 2024-02-28 Cooperative journals: 《Research in Astronomy and Astrophysics》
Abstract： Pulsar detection has become an active research topic in radio astronomy recently. One of the essential procedures for pulsar detection is pulsar candidate sifting (PCS), a procedure for identifying potential pulsar signals in a survey. However, pulsar candidates are always class-imbalanced, as most candidates are non-pulsars such as RFI and only a tiny part of them are from real pulsars. Class imbalance can greatly affect the performance of machine learning (ML) models, resulting in a heavy cost as some real pulsars are misjudged. To deal with the problem, techniques of choosing relevant features to discriminate pulsars from non-pulsars are focused on, which is known as feature selection. Feature selection is a process of selecting a subset of the most relevant features from a feature pool. The distinguishing features between pulsars and non-pulsars can significantly improve the performance of the classifier even if the data are highly imbalanced. In this work, an algorithm for feature selection called the K-fold Relief-Greedy (KFRG) algorithm is designed. KFRG is a two-stage algorithm. In the first stage, it filters out some irrelevant features according to their K-fold Relief scores, while in the second stage, it removes the redundant features and selects the most relevant features by a forward greedy search strategy. Experiments on the data set of the High Time Resolution Universe survey verified that ML models based on KFRG are capable of PCS, correctly separating pulsars from non-pulsars even if the candidates are highly class-imbalanced.
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