We report a further investigation of the optical low frequency quasi periodic oscillations(LF QPOs)detected in the black hole transient MAXI J1820+070 in the 2018 observations with the YFOSC mounted on Lijiang 2.4 m t...We report a further investigation of the optical low frequency quasi periodic oscillations(LF QPOs)detected in the black hole transient MAXI J1820+070 in the 2018 observations with the YFOSC mounted on Lijiang 2.4 m telescope(LJT).In addition,we make use of the Insight-HXMT/HE observations to measure the properties of the quasi-simultaneous X-ray LF QPOs of MAXI J1820+070 on the same day.We compared the centroid frequency,the full width at half maximum(FWHM)and the fractional rms of the LF QPOs in both wavelength ranges.We found that the centroid frequency of the optical QPO is at a frequency of 51.58 m Hz,which is consistent with that of the X-ray LF QPO detected on the same day within 1 m Hz.We also found that the FWHM of the optical LF QPO is significantly smaller than that of the X-ray LF QPO,indicating that the optical QPO has a higher coherence.The quasi-simultaneous optical and the X-ray LF QPO at a centroid frequency of about 52 m Hz suggests that the actual mechanisms of these LF QPOs as the Lense-Thirring precession should work in the vicinity of a radius of about 80-117 gravitational radii(R_(g)=GM/c^(2),M is the mass of the black hole)from the black hole if the QPO frequency is related to a proxy of the orbital frequency in the accretion fiow as the Lense-Thirring precession model suggests.Furthermore,the apparent higher coherence of the optical QPO favors that it is a more original signal as compared with the X-ray QPO.展开更多
BACKGROUND Nonalcoholic fatty liver disease(NAFLD)includes a spectrum of conditions,progressing from mild steatosis to advanced fibrosis.Sarcopenia,characterized by decreased muscle strength and mass,shares common pat...BACKGROUND Nonalcoholic fatty liver disease(NAFLD)includes a spectrum of conditions,progressing from mild steatosis to advanced fibrosis.Sarcopenia,characterized by decreased muscle strength and mass,shares common pathophysiological traits with NAFLD.An association exists between sarcopenia and increased NAFLD prevalence.However,data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent.AIM To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD.METHODS We conducted a comprehensive search for relevant studies in MEDLINE,Embase,and Scopus from their inception to June 2023.We included studies that focused on patients with NAFLD,reported the prevalence of sarcopenia as the primary outcome,and examined secondary outcomes,such as liver fibrosis and other adverse events.We also used the Newcastle-Ottawa scale for quality assessment.RESULTS Of the 29 studies included,the prevalence of sarcopenia in NAFLD varied widely(1.6%to 63.0%),with 20 studies reporting a prevalence of more than 10.0%.Substantial heterogeneity was noted in the measurement modalities for sarcopenia.Sarcopenia was associated with a higher risk of advanced fibrosis(odd ratio:1.97,95%confidence interval:1.44-2.70).Increased odds were consistently observed in fibrosis assessment through biopsy,NAFLD fibrosis score/body mass index,aspartate aminotransferase to alanine aminotransferase ratio,diabetes(BARD)score,and transient elastography,whereas the fibrosis-4 score showed no such association.Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis,insulin resistance,cardiovascular risks,and mortality.CONCLUSION This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients.The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings.This review demonstrates the multidimensional impact of sarcopenia on NAFLD,indicating its importance beyond liver-related events to include cardiovascular risks,mortality,and metabolic complications.展开更多
The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radi...The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radius has been calculated by taking into account the effect of feedback radiation and the deviation of disk rotation from Keplerian. Results have been applied to the observations and possible interpretations have been proposed for the X-ray spectra and quasiperiodic oscillations.展开更多
Fe+ ion beams with the energy of 110 keV were implanted into films of L(+)-cysteine (HSCH2CH(NH2)COOH). One of the single crystals grown in hydrochloric acid solution with the implanted samples through slow evaporatio...Fe+ ion beams with the energy of 110 keV were implanted into films of L(+)-cysteine (HSCH2CH(NH2)COOH). One of the single crystals grown in hydrochloric acid solution with the implanted samples through slow evaporation was structurally characterized by the X-ray crystallography. The crystal is monoclinic, space group C2, with a = 1.8534(4) nm, b=0.5234(1) nm, c = 0.7212(1) nm, β=103.722°, V = 0.67965(3) nm3, Z = 4, F(000) = 144.0, Dclac = 1.763 g·cm-3, μ (MoKa) = 1.06 mm-1, T = 293(2) K.R = 0.0379, wR = 0.0835 for 660 observed reflections (I】2σ(I)). The structural formula of the crystal compound is (CH2CH(NH2)NO2)ClFe (Mr = 180.38u). Products of heavy ion beam irradiation were purified and it was directly confirmed that the implanted Fe+ ions had been deposited in the novel molecules. The same doses of Fe+ ion beams of the same energy were implanted into films of L(+)-cysteine hydrochloride monohydrate. FTIR spectroscopy of the implanted samples proved that some of the original molecules were展开更多
We review recent progress in theoretical understanding of X-ray binaries,which has largely been driven by new observations.We select several topics including formation of compact low-mass X-ray binaries,the evolutiona...We review recent progress in theoretical understanding of X-ray binaries,which has largely been driven by new observations.We select several topics including formation of compact low-mass X-ray binaries,the evolutionary connection between low-mass X-ray binaries and binary and millisecond radio pulsars,and ultraluminous X-ray sources,to illustrate the interplay between theories and observations.展开更多
In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry(eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting wh...In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry(eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-ray binaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-ray bursts. eXTP will be excellently suited to study one common aspect of these objects: their often transient nature. Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.展开更多
Based the Alfven wave oscillation model(AWOM) and relativistic precession model(RPM) for twin kHz QPOs,we estimate the emission positions of most detected kHz QPOs to be at r=18+/-3 km(R/15 km),except Cir X-1 at r-30+...Based the Alfven wave oscillation model(AWOM) and relativistic precession model(RPM) for twin kHz QPOs,we estimate the emission positions of most detected kHz QPOs to be at r=18+/-3 km(R/15 km),except Cir X-1 at r-30+/-5 km(R/15 km).For the proposed Keplerian frequency as an upper limit to kHz QPO,the spin effects in Kerr Spacetime are discussed,which have about a 5%(2%) modification for that of the Schwarzchild case for the spin frequency of 1000(400) Hz.The application to the four typical QPO sources,Cir X-1,Sco X-1,SAX J1808.4-3658 and XTE 1807-294,is mentioned.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘We report a further investigation of the optical low frequency quasi periodic oscillations(LF QPOs)detected in the black hole transient MAXI J1820+070 in the 2018 observations with the YFOSC mounted on Lijiang 2.4 m telescope(LJT).In addition,we make use of the Insight-HXMT/HE observations to measure the properties of the quasi-simultaneous X-ray LF QPOs of MAXI J1820+070 on the same day.We compared the centroid frequency,the full width at half maximum(FWHM)and the fractional rms of the LF QPOs in both wavelength ranges.We found that the centroid frequency of the optical QPO is at a frequency of 51.58 m Hz,which is consistent with that of the X-ray LF QPO detected on the same day within 1 m Hz.We also found that the FWHM of the optical LF QPO is significantly smaller than that of the X-ray LF QPO,indicating that the optical QPO has a higher coherence.The quasi-simultaneous optical and the X-ray LF QPO at a centroid frequency of about 52 m Hz suggests that the actual mechanisms of these LF QPOs as the Lense-Thirring precession should work in the vicinity of a radius of about 80-117 gravitational radii(R_(g)=GM/c^(2),M is the mass of the black hole)from the black hole if the QPO frequency is related to a proxy of the orbital frequency in the accretion fiow as the Lense-Thirring precession model suggests.Furthermore,the apparent higher coherence of the optical QPO favors that it is a more original signal as compared with the X-ray QPO.
文摘BACKGROUND Nonalcoholic fatty liver disease(NAFLD)includes a spectrum of conditions,progressing from mild steatosis to advanced fibrosis.Sarcopenia,characterized by decreased muscle strength and mass,shares common pathophysiological traits with NAFLD.An association exists between sarcopenia and increased NAFLD prevalence.However,data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent.AIM To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD.METHODS We conducted a comprehensive search for relevant studies in MEDLINE,Embase,and Scopus from their inception to June 2023.We included studies that focused on patients with NAFLD,reported the prevalence of sarcopenia as the primary outcome,and examined secondary outcomes,such as liver fibrosis and other adverse events.We also used the Newcastle-Ottawa scale for quality assessment.RESULTS Of the 29 studies included,the prevalence of sarcopenia in NAFLD varied widely(1.6%to 63.0%),with 20 studies reporting a prevalence of more than 10.0%.Substantial heterogeneity was noted in the measurement modalities for sarcopenia.Sarcopenia was associated with a higher risk of advanced fibrosis(odd ratio:1.97,95%confidence interval:1.44-2.70).Increased odds were consistently observed in fibrosis assessment through biopsy,NAFLD fibrosis score/body mass index,aspartate aminotransferase to alanine aminotransferase ratio,diabetes(BARD)score,and transient elastography,whereas the fibrosis-4 score showed no such association.Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis,insulin resistance,cardiovascular risks,and mortality.CONCLUSION This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients.The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings.This review demonstrates the multidimensional impact of sarcopenia on NAFLD,indicating its importance beyond liver-related events to include cardiovascular risks,mortality,and metabolic complications.
基金the National Natural Science Foundation of China and Ph.D. Research Funds
文摘The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radius has been calculated by taking into account the effect of feedback radiation and the deviation of disk rotation from Keplerian. Results have been applied to the observations and possible interpretations have been proposed for the X-ray spectra and quasiperiodic oscillations.
基金National Natural Science Foundation of the People’s Republic of China“The thermal evolution and X-ray bursts in accreting strange stars”(12263006)“A combining study of the theoretical simulations and observations about the structure and evolution of magnetic massive stars and related objects”(U2031204)Natural Science Foundation of Xinjiang“The study of crust cooling of soft X-ray transients”(2020D01C063).
基金This work was supported by the National Natural Science Foundation of China (Grant No.19975060)the Scientific Foundation of "95" Fundamental Research from the Chinese Academy of Sciences (Grant No. KJ952-S1-424).
文摘Fe+ ion beams with the energy of 110 keV were implanted into films of L(+)-cysteine (HSCH2CH(NH2)COOH). One of the single crystals grown in hydrochloric acid solution with the implanted samples through slow evaporation was structurally characterized by the X-ray crystallography. The crystal is monoclinic, space group C2, with a = 1.8534(4) nm, b=0.5234(1) nm, c = 0.7212(1) nm, β=103.722°, V = 0.67965(3) nm3, Z = 4, F(000) = 144.0, Dclac = 1.763 g·cm-3, μ (MoKa) = 1.06 mm-1, T = 293(2) K.R = 0.0379, wR = 0.0835 for 660 observed reflections (I】2σ(I)). The structural formula of the crystal compound is (CH2CH(NH2)NO2)ClFe (Mr = 180.38u). Products of heavy ion beam irradiation were purified and it was directly confirmed that the implanted Fe+ ions had been deposited in the novel molecules. The same doses of Fe+ ion beams of the same energy were implanted into films of L(+)-cysteine hydrochloride monohydrate. FTIR spectroscopy of the implanted samples proved that some of the original molecules were
基金supported by the National Basic Research Program of China (Grant No. 2009CB-824800)the National Natural Science Foundation of China (Grant No. 10873008)
文摘We review recent progress in theoretical understanding of X-ray binaries,which has largely been driven by new observations.We select several topics including formation of compact low-mass X-ray binaries,the evolutionary connection between low-mass X-ray binaries and binary and millisecond radio pulsars,and ultraluminous X-ray sources,to illustrate the interplay between theories and observations.
基金supported by the Royal Society,ERC Starting(Grant No.639217)he European Union Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Global Fellowship(Grant No.703916)+10 种基金the National Natural Science Foundation of China(Grant Nos.11233001,11773014,11633007,11403074,11333005,11503008,and 11590781)the National Basic Research Program of China(Grant No.2015CB857100)NASA(Grant No.NNX13AD28A)an ARC Future Fellowship(Grant No.FT120100363)the National Science Foundation(Grant No.PHY-1430152)the Spanish MINECO(Grant No.AYA2016-76012-C3-1-P)the ICCUB(Unidad de Excelencia’Maria de Maeztu’)(Grant No.MDM-2014-0369)EU’s Horizon Programme through a Marie Sklodowska-Curie Fellowship(Grant No.702638)the Polish National Science Center(Grant Nos.2015/17/B/ST9/03422,2015/18/M/ST9/00541,2013/10/M/ST9/00729,and 2015/18/A/ST9/00746)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA15020100)the NWO Veni Fellowship(Grant No.639.041.647)
文摘In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry(eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-ray binaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-ray bursts. eXTP will be excellently suited to study one common aspect of these objects: their often transient nature. Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.
基金supported by the National Basic Research Program of China (Grant No. 2009CB824800)the National Natural Science Foundation of China (Grant No. 10773017)
文摘Based the Alfven wave oscillation model(AWOM) and relativistic precession model(RPM) for twin kHz QPOs,we estimate the emission positions of most detected kHz QPOs to be at r=18+/-3 km(R/15 km),except Cir X-1 at r-30+/-5 km(R/15 km).For the proposed Keplerian frequency as an upper limit to kHz QPO,the spin effects in Kerr Spacetime are discussed,which have about a 5%(2%) modification for that of the Schwarzchild case for the spin frequency of 1000(400) Hz.The application to the four typical QPO sources,Cir X-1,Sco X-1,SAX J1808.4-3658 and XTE 1807-294,is mentioned.
