We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the de...We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the deep learning method.Among them,optical and/or infrared counterparts are identified for 41,425 FR-Ⅱs.This catalog spans luminosities 2.63×10^(22)≤L_(rad)≤6.76×10^(29)W Hz^(-1)and redshifts up to z=5.01.The spectroscopic classification indicates that there are 1431 low-excitation radio galaxies and 260 high-excitation radio galaxies.Among the spectroscopically identified sources,black hole masses are estimated for 4837 FR-Is,which are in 10^(7.5)■M_(BH)■10^(9.5)M_(⊙).Interestingly,this catalog reveals a couple of giant radio galaxies(GRGs),which are already in the existing GRG catalog,confirming the efficiency of this FR-I catalog.Furthermore,284new GRGs are unveiled in this new FR-I sample;they have the largest projected sizes ranging from 701 to1209 kpc and are located at redshifts 0.31<z<2.42.Finally,we explore the distribution of the jet position angle and it shows that the faint Images of the FIRST images are significantly affected by the systematic effect(the observing beams).The method presented in this work is expected to be applicable to the radio sky surveys that are currently being conducted because they have finely refined telescope arrays.On the other hand,we are expecting that further new methods will be dedicated to solving this problem.展开更多
Objective:To compare the eflect of zoledronic acid in treatment and prevention of osteoporosis with placebo.Methods:Random control trials regarding zoleilroiiic acid in treatment of osteoporosis were retrieved by sele...Objective:To compare the eflect of zoledronic acid in treatment and prevention of osteoporosis with placebo.Methods:Random control trials regarding zoleilroiiic acid in treatment of osteoporosis were retrieved by selecting Medline.EMbase and Pubmed databases till April 2012. The RevMan software was used for all of the statistical analysis.Results:A total of 9 trials were included in this meta-analysis.The pooled effect shewed that zoledronic acid could increase the bone mineral density by 2.98 times compared with placebo,and reduce the rate of fracture in patients by 32%.The results should the zoledronic acid intervention had significantly less serious adverse events than controls,and the odds ratio was 0.81(0.76-0.87).The longer term intervention, more than 12 months intervention,could gain a better prevention effect for osteoporosis(OR,95% CI for RMD was 3.35.2.77-3.92:for fracture was 0.67.0.54-0.82).Conclusions:This present study shows that zoledronic acid could be effective approach in the prevention of osteoporosis,and could increase the bone mineral density and reduce the risk ol facture.展开更多
BACKGROUND Granulomatous lobular mastitis(GLM)is a type of benign chronic inflammatory disease that poses therapeutic challenges to healthcare providers.The diagnosis of GLM relies on tissue biopsy,and incorrect treat...BACKGROUND Granulomatous lobular mastitis(GLM)is a type of benign chronic inflammatory disease that poses therapeutic challenges to healthcare providers.The diagnosis of GLM relies on tissue biopsy,and incorrect treatment may lead to delayed diagnosis,considerable aesthetic damage,and even mastectomy.CASE SUMMARY We report the case of a 37-year-old Chinese woman who was lactating and had GLM in both breasts.At the time of treatment,the right breast had a mass of approximately 15 cm×11 cm,which was hard and had poor mobility.Multiple skin ulcerations and pus spills were also observed on the surface of the breast.The left breast had a mass of about 13 cm×9 cm,which was hard and had poor mobility.CONCLUSION Herein,we report a case of bilateral GLM in a lactating woman that was successfully treated with traditional Chinese medicine(TCM),without the requirement for surgery or other treatments.Therefore,TCM may have advantages in the nonsurgical treatment of GLM.展开更多
A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multi...A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well.展开更多
Objective:Estimate predictive associations of marital status with social dysfunction in schizophrenia patients.Methods:817 schizophrenia patients lived in the community of Dongguan,Guangdong province,China,were invest...Objective:Estimate predictive associations of marital status with social dysfunction in schizophrenia patients.Methods:817 schizophrenia patients lived in the community of Dongguan,Guangdong province,China,were investigated with the Social Disability Screening Schedule(SDSS)during a three-month period(1.2010e3.2010).The demographic data were harvested.The c2 test,t test,and fisher's exact were used for comparisons between groups,as appropriate.Multinomial logistic regression(MLR)was used to analyze the predictive associations of demographic variables to the grading of social dysfunctions.Results:The study group consisted of male and female patients aged 16e59 years,407 females,and 410 males with the mean age(40.7±9.5)years.Analysis of the data revealed significant differences in course of disease and marital status among patients(with and without dysfunction).The married patient made a significant difference with divorced/widowed patient in mildlyemoderately social dysfunction.There was a significant difference in married and never-married patient with mildly and profoundly social dysfunction.Significant differences were noticed in the self care and occupational roles of the married patient with that of the never-married.Conclusion:This study confirmed that bad marital status is associated with higher odds of social dysfunction among patients with schizophrenia living in the community.These effects should be included in considerations of public health investments in preventing and treating mental disorders.展开更多
The relativistic electrons rotate in the enhanced magnetic field of the supernova remnants and emit the synchrotron radio emission.We aim to use the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to obtain...The relativistic electrons rotate in the enhanced magnetic field of the supernova remnants and emit the synchrotron radio emission.We aim to use the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to obtain a sensitive continuum map of the supernova remnant VRO 42.05.01(G166.0+4.3)at 1240 MHz.The 500 MHz bandwidth is divided into low and high-frequency bands centered at 1085 and 1383 MHz to investigate the spectral index variations within the remnant,together with the Effelsberg 2695 MHz data.We obtained an integrated flux density of 6.2±0.4 Jy at 1240 MHz for VRO 42.05.01,consistent with previous results.The spectral index found from temperature-temperature plot(TT-plot)between 1240 and 2695 MHz agrees with previous values from408 MHz up to 5 GHz.The three-band spectral index distribution shows a clear flatter value ofα~-0.33 in the shell region and steeper index ofα=-0.36 to-0.54 in the wing region.The flatter spectral index in the shell region could be attributed to a second-order Fermi process in the turbulent medium in the vicinity of the shock and/or a higher compression ratio of shock and a high post-shock density than that in elsewhere.展开更多
We discovered three large HⅡ regions: G148.8+2.3, G149.5+0.0 and G169.9+2.0 in the Sino-German A6 cm polarization survey of the Galactic plane. They have been identified based on the flat spectral indexes and the...We discovered three large HⅡ regions: G148.8+2.3, G149.5+0.0 and G169.9+2.0 in the Sino-German A6 cm polarization survey of the Galactic plane. They have been identified based on the flat spectral indexes and the strong infrared emission properties.展开更多
The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simul...The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simulated numerically and its aerodynamic force coefficients are calculated under the condition of the deflection angles vary from 0° to 8°, angles of attack, 0°-8°, and mach numbers, 2 to 5. Coupling these aerodynamic coefficients with the plumb plane ballistic equations, the extended flight range has been calculated. Furthermore, the genetic algorithm(GA) is employed for the solution of maximum range of the deflected missile.展开更多
The shell-type TeV source HESS J1912+101 was tentatively identified as an old supernova remnant, but is missing counterparts at radio and other frequencies. We analysed the Sino-German Urumqiλ6 cm survey and the Effe...The shell-type TeV source HESS J1912+101 was tentatively identified as an old supernova remnant, but is missing counterparts at radio and other frequencies. We analysed the Sino-German Urumqiλ6 cm survey and the Effelsberg λ11 cm and λ21 cm surveys to identify radio emission from HESS J1912+101 to clarify the question of a supernova origin. We find a partial shell of excessive polarisation at λ6 cm at the periphery of HESS J1912+101. At λ11 cm, its polarised emission is faint and suffers from depolarisation, while at λ21 cm, no related polarisation is seen. We could not separate the shell's total intensity signal from the confusing intense diffuse emission from the inner Galactic plane. However, a high percentage of polarisation in the shell's synchrotron emission is indicated. Our results support earlier suggestions that HESS J1912+101 is an old supernova remnant. The synchrotron emission is highly polarised,which is typical for evolved supernova remnants with low surface brightness.展开更多
We present a radio polarization study of the supernova remnant CTB 80 based on images at1420 MHz from the Canadian Galactic Plane Survey,at 2695 MHz from the Effelsberg survey of the Galactic plane and at 4800 MHz fro...We present a radio polarization study of the supernova remnant CTB 80 based on images at1420 MHz from the Canadian Galactic Plane Survey,at 2695 MHz from the Effelsberg survey of the Galactic plane and at 4800 MHz from the Sino-Germanλ6 cm polarization survey of the Galactic plane.We obtained a rotation measure(RM)map using polarization angles at 2695 MHz and 4800 MHz as the polarization percentages are similar at these two frequencies.RM exhibits a transition from positive values to negative values along one of the shells hosting the pulsar PSR B1951+32 and its pulsar wind nebula.The reason for the change in sign remains unclear.We identified a partial shell structure,which is bright in polarized intensity but weak in total intensity.This structure could be part of CTB 80 or part of a new supernova remnant unrelated to CTB 80.展开更多
We present total-intensity and polarized-intensity images of the Cygnus Loop supernova remnant(SNR)observed by the Five-hundred-meter Aperture Spherical radio Telescope.The high angular-resolution and high-sensitivity...We present total-intensity and polarized-intensity images of the Cygnus Loop supernova remnant(SNR)observed by the Five-hundred-meter Aperture Spherical radio Telescope.The high angular-resolution and high-sensitivity images enable us to thoroughly compare the properties of the northern part with the southern part of the SNR.The central filament in the northern part and the southern part have a similar foreground rotation measure,meaning their distances are likely similar.The polarization analysis indicates that the random magnetic field is larger than the regular field in the northern part,but negligible in the southern part.The total-intensity image is decomposed into components of various angular scales,and the brightness-temperature spectral index of the shell structures in the northern part is similar to that in the southern part in the component images.All the evidence suggests that the northern and southern parts of the Cygnus Loop are situated and thus evolved in different environments of interstellar medium,while belonging to the same SNR.展开更多
We report on the continuum and polarization observations of the Cygnus Loop supernova remnant(SNR)conducted by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).FAST observations provide high angular res...We report on the continuum and polarization observations of the Cygnus Loop supernova remnant(SNR)conducted by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).FAST observations provide high angular resolution and high sensitivity images of the SNR,which will help to disentangle its nature.We obtained Stokes I,Q and U maps over the frequency range of 1.03-1.46 GHz split into channels of 7.63 kHz.The original angular resolution is in the range of~3’-~3.’8,and we combined all the data at a common resolution of 4’.The temperature scale of the total intensity and the spectral index from the in-band temperature-temperature plot are consistent with previous observations,which validates the data calibration and map-making procedures.The rms sensitivity for the band-averaged total-intensity map is about 20 mK in brightness temperature,which is at the level of confusion limit.For the first time,we apply rotation measure(RM)synthesis to the Cygnus Loop to obtain the polarization intensity and RM maps.The rms sensitivity for polarization is about 5 mK,far below the total-intensity confusion limit.We also obtained RMs of eight extragalactic sources,and demonstrate that the wide-band frequency coverage helps to overcome the ambiguity of RM determinations.展开更多
Objective: Aberrant expression of ten-eleven translocation 1 (TET1) plays a critical role in tumor development and progression. We systematically summarized the latest research progress on the role and mechanisms o...Objective: Aberrant expression of ten-eleven translocation 1 (TET1) plays a critical role in tumor development and progression. We systematically summarized the latest research progress on the role and mechanisms of TET1 in cancer biology. Data Sources: Relevant articles published in English from 1980 to April 2016 were selected from the PubMed database. Tile terms "'ten-eleven translocation 1," "'SmC," '5hmC," 'microRNA,'" "hypoxia," and "'embryonic stem cell'" were used tbr the search. Study Selection: Articles focusing on the role and mechanism ofTETI in tumor were reviewed, including clinical and basic research articles. Results: TET proteins, the key enzymes converting 5-methylcytosine to 5-hydroxymethylcytosine, play vital roles in DNA demethylation regulation. Recent studies have shown that loss of TETI is associated with tumorigenesis and can be used as a potential biomarker for cancer therapy, which indicates that TETI serves as tumor suppressor gene. Moreover, besides its dioxygenase activity, TET1 could induce epithelial-mesenchymal transition and act as a coactivator to regulate gene transcription, such as developmental regulator in embryonic stem cells (ESCs) and hypoxia-responsive gene in cancer. The regulation of TETl is also correlated with microRNA in a posttranscriptional modification process. Hence, it is complex but critical to coaprehend the mechanisms of TETI in the biology of ESCs and cancer. Conclusions: TET I not only serves as a demethylation enzyme but also plays multiple roles during tumorigenesis and progression. More studies should be carried out to elucidate the exact mechanisms of TETI and its associations with cancer betbre considering it as a therapeutic tool.展开更多
One new stenine-type alkaloid, tuberostemonine D (1), together with five known stenine-type alkaloids (2-6) and two known stemoninine-type alkaloids (7 and 8), were isolated from the roots of Stemona tuberosa. T...One new stenine-type alkaloid, tuberostemonine D (1), together with five known stenine-type alkaloids (2-6) and two known stemoninine-type alkaloids (7 and 8), were isolated from the roots of Stemona tuberosa. Their structures were elucidated by extensive spectroscopic methods (IR, UV, MS, 1D and 2D NMR), and the structure of I was further confirmed by X-ray diffraction analysis. First simultaneous isolation ofstenine- and stemoninine-type alkaloids not only added a new chemical type and increased the chemical diversity of Stemona tuberosa, but also provided chemotaxonomic clues for the close relationship between genera Stemona and Stichoneuron, and favored retaining them in the same family.展开更多
As the rate-determining step in native chemical ligation reactions, the thiol–thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoreti...As the rate-determining step in native chemical ligation reactions, the thiol–thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol–thioester exchange step. According to the calculation results, the thiol–thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect(i.e. conjugation and hyper-conjugation effects) becomes important when the steric hindrance is insignificant.展开更多
基金supported by the National SKA Program of China(2022SKA0120101,2022SKA0130100,2022SKA 0130104)the National Natural Science Foundation of China(NSFC,grant No.12103013)+5 种基金the Foundation of Science and Technology of Guizhou Province(Nos.(2021)023)the Foundation of Guizhou Provincial Education Department(Nos.KY(2021)303,KY(2020)003,KY(2023)059)supported by the National Natural Science Foundation of China(NSFC,grant Nos.12103076 and 12233005)the National Key R&D Program of China(2020YFE0202100)the Shanghai Sailing Program(21YF1455300)the China Postdoctoral Science Foundation(2021M693267)。
文摘We present an independent catalog(FRIIRGcat)of 45,241 Fanaroff–Riley TypeⅡ(FR-Ⅱ)radio galaxies compiled from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters(FIRST)survey and employed the deep learning method.Among them,optical and/or infrared counterparts are identified for 41,425 FR-Ⅱs.This catalog spans luminosities 2.63×10^(22)≤L_(rad)≤6.76×10^(29)W Hz^(-1)and redshifts up to z=5.01.The spectroscopic classification indicates that there are 1431 low-excitation radio galaxies and 260 high-excitation radio galaxies.Among the spectroscopically identified sources,black hole masses are estimated for 4837 FR-Is,which are in 10^(7.5)■M_(BH)■10^(9.5)M_(⊙).Interestingly,this catalog reveals a couple of giant radio galaxies(GRGs),which are already in the existing GRG catalog,confirming the efficiency of this FR-I catalog.Furthermore,284new GRGs are unveiled in this new FR-I sample;they have the largest projected sizes ranging from 701 to1209 kpc and are located at redshifts 0.31<z<2.42.Finally,we explore the distribution of the jet position angle and it shows that the faint Images of the FIRST images are significantly affected by the systematic effect(the observing beams).The method presented in this work is expected to be applicable to the radio sky surveys that are currently being conducted because they have finely refined telescope arrays.On the other hand,we are expecting that further new methods will be dedicated to solving this problem.
文摘Objective:To compare the eflect of zoledronic acid in treatment and prevention of osteoporosis with placebo.Methods:Random control trials regarding zoleilroiiic acid in treatment of osteoporosis were retrieved by selecting Medline.EMbase and Pubmed databases till April 2012. The RevMan software was used for all of the statistical analysis.Results:A total of 9 trials were included in this meta-analysis.The pooled effect shewed that zoledronic acid could increase the bone mineral density by 2.98 times compared with placebo,and reduce the rate of fracture in patients by 32%.The results should the zoledronic acid intervention had significantly less serious adverse events than controls,and the odds ratio was 0.81(0.76-0.87).The longer term intervention, more than 12 months intervention,could gain a better prevention effect for osteoporosis(OR,95% CI for RMD was 3.35.2.77-3.92:for fracture was 0.67.0.54-0.82).Conclusions:This present study shows that zoledronic acid could be effective approach in the prevention of osteoporosis,and could increase the bone mineral density and reduce the risk ol facture.
基金Supported by Natural Science Foundation of Shandong Province,No.ZR2017BH107the Shandong Province TCM Science and Technology Development Program,No.2019-0090 and No.2019-0160+2 种基金Jinan Clinical Science and Technology Innovation Plan,No.202019157the Qilu Hygiene and Health Leading Talent Cultivation Project,Lwrz[2020]No.3the Zhaoyang Talent Project of the Affiliated Hospital of Shandong University of Traditional Chinese Medicine。
文摘BACKGROUND Granulomatous lobular mastitis(GLM)is a type of benign chronic inflammatory disease that poses therapeutic challenges to healthcare providers.The diagnosis of GLM relies on tissue biopsy,and incorrect treatment may lead to delayed diagnosis,considerable aesthetic damage,and even mastectomy.CASE SUMMARY We report the case of a 37-year-old Chinese woman who was lactating and had GLM in both breasts.At the time of treatment,the right breast had a mass of approximately 15 cm×11 cm,which was hard and had poor mobility.Multiple skin ulcerations and pus spills were also observed on the surface of the breast.The left breast had a mass of about 13 cm×9 cm,which was hard and had poor mobility.CONCLUSION Herein,we report a case of bilateral GLM in a lactating woman that was successfully treated with traditional Chinese medicine(TCM),without the requirement for surgery or other treatments.Therefore,TCM may have advantages in the nonsurgical treatment of GLM.
基金The work was supported by the National Natural Science Foundation of China(No.51874045)National Natural Science Foundation-Youth Foundation(52104056)+2 种基金Department of Natural Resources of Guangdong Province(GDNRC[2021]56)Postdoctoral innovative talents support program in China(BX2021374)Scientific Research Program of Hubei Provincial Department of Education(T2021004).
文摘A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well.
文摘Objective:Estimate predictive associations of marital status with social dysfunction in schizophrenia patients.Methods:817 schizophrenia patients lived in the community of Dongguan,Guangdong province,China,were investigated with the Social Disability Screening Schedule(SDSS)during a three-month period(1.2010e3.2010).The demographic data were harvested.The c2 test,t test,and fisher's exact were used for comparisons between groups,as appropriate.Multinomial logistic regression(MLR)was used to analyze the predictive associations of demographic variables to the grading of social dysfunctions.Results:The study group consisted of male and female patients aged 16e59 years,407 females,and 410 males with the mean age(40.7±9.5)years.Analysis of the data revealed significant differences in course of disease and marital status among patients(with and without dysfunction).The married patient made a significant difference with divorced/widowed patient in mildlyemoderately social dysfunction.There was a significant difference in married and never-married patient with mildly and profoundly social dysfunction.Significant differences were noticed in the self care and occupational roles of the married patient with that of the never-married.Conclusion:This study confirmed that bad marital status is associated with higher odds of social dysfunction among patients with schizophrenia living in the community.These effects should be included in considerations of public health investments in preventing and treating mental disorders.
基金support from the National Key R&D Program of China(2018YFE0202900)the early science Project Program of the Key Laboratory of FAST。
文摘The relativistic electrons rotate in the enhanced magnetic field of the supernova remnants and emit the synchrotron radio emission.We aim to use the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to obtain a sensitive continuum map of the supernova remnant VRO 42.05.01(G166.0+4.3)at 1240 MHz.The 500 MHz bandwidth is divided into low and high-frequency bands centered at 1085 and 1383 MHz to investigate the spectral index variations within the remnant,together with the Effelsberg 2695 MHz data.We obtained an integrated flux density of 6.2±0.4 Jy at 1240 MHz for VRO 42.05.01,consistent with previous results.The spectral index found from temperature-temperature plot(TT-plot)between 1240 and 2695 MHz agrees with previous values from408 MHz up to 5 GHz.The three-band spectral index distribution shows a clear flatter value ofα~-0.33 in the shell region and steeper index ofα=-0.36 to-0.54 in the wing region.The flatter spectral index in the shell region could be attributed to a second-order Fermi process in the turbulent medium in the vicinity of the shock and/or a higher compression ratio of shock and a high post-shock density than that in elsewhere.
基金the National Natural Science Foundation of China
文摘We discovered three large HⅡ regions: G148.8+2.3, G149.5+0.0 and G169.9+2.0 in the Sino-German A6 cm polarization survey of the Galactic plane. They have been identified based on the flat spectral indexes and the strong infrared emission properties.
文摘The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simulated numerically and its aerodynamic force coefficients are calculated under the condition of the deflection angles vary from 0° to 8°, angles of attack, 0°-8°, and mach numbers, 2 to 5. Coupling these aerodynamic coefficients with the plumb plane ballistic equations, the extended flight range has been calculated. Furthermore, the genetic algorithm(GA) is employed for the solution of maximum range of the deflected missile.
基金supported by the National Natural Science Foundation of China (Grant No.11763008)
文摘The shell-type TeV source HESS J1912+101 was tentatively identified as an old supernova remnant, but is missing counterparts at radio and other frequencies. We analysed the Sino-German Urumqiλ6 cm survey and the Effelsberg λ11 cm and λ21 cm surveys to identify radio emission from HESS J1912+101 to clarify the question of a supernova origin. We find a partial shell of excessive polarisation at λ6 cm at the periphery of HESS J1912+101. At λ11 cm, its polarised emission is faint and suffers from depolarisation, while at λ21 cm, no related polarisation is seen. We could not separate the shell's total intensity signal from the confusing intense diffuse emission from the inner Galactic plane. However, a high percentage of polarisation in the shell's synchrotron emission is indicated. Our results support earlier suggestions that HESS J1912+101 is an old supernova remnant. The synchrotron emission is highly polarised,which is typical for evolved supernova remnants with low surface brightness.
基金supported by the National Natural Science Foundation of China (Grant No. 11763008)supported by the CAS-NWO cooperation programme (Grant No. GJHZ1865)the National Natural Science Foundation of China (Grant No. U1831103).
文摘We present a radio polarization study of the supernova remnant CTB 80 based on images at1420 MHz from the Canadian Galactic Plane Survey,at 2695 MHz from the Effelsberg survey of the Galactic plane and at 4800 MHz from the Sino-Germanλ6 cm polarization survey of the Galactic plane.We obtained a rotation measure(RM)map using polarization angles at 2695 MHz and 4800 MHz as the polarization percentages are similar at these two frequencies.RM exhibits a transition from positive values to negative values along one of the shells hosting the pulsar PSR B1951+32 and its pulsar wind nebula.The reason for the change in sign remains unclear.We identified a partial shell structure,which is bright in polarized intensity but weak in total intensity.This structure could be part of CTB 80 or part of a new supernova remnant unrelated to CTB 80.
基金supported by the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CASsupported by the Science&Technology Department of Yunnan Province—Yunnan University Joint Funding(2019FY003005)supported by the CASNWO cooperation program(Grant No.GJHZ1865)。
文摘We present total-intensity and polarized-intensity images of the Cygnus Loop supernova remnant(SNR)observed by the Five-hundred-meter Aperture Spherical radio Telescope.The high angular-resolution and high-sensitivity images enable us to thoroughly compare the properties of the northern part with the southern part of the SNR.The central filament in the northern part and the southern part have a similar foreground rotation measure,meaning their distances are likely similar.The polarization analysis indicates that the random magnetic field is larger than the regular field in the northern part,but negligible in the southern part.The total-intensity image is decomposed into components of various angular scales,and the brightness-temperature spectral index of the shell structures in the northern part is similar to that in the southern part in the component images.All the evidence suggests that the northern and southern parts of the Cygnus Loop are situated and thus evolved in different environments of interstellar medium,while belonging to the same SNR.
基金supported by the National Natural Science Foundation of China (NSFC, No. 11763008)the Science & Technology Department of Yunnan Province-Yunnan University Joint Funding (2019FY003005)+2 种基金supported by the CAS-NWO cooperation programme (Grant No. GJHZ1865)supported by the National Natural Science Foundation of China (Grant No. U1831103)supported by the Key Lab of FAST, National Astronomical Observatories, Chinese Academy of Sciences
文摘We report on the continuum and polarization observations of the Cygnus Loop supernova remnant(SNR)conducted by the Five-hundred-meter Aperture Spherical radio Telescope(FAST).FAST observations provide high angular resolution and high sensitivity images of the SNR,which will help to disentangle its nature.We obtained Stokes I,Q and U maps over the frequency range of 1.03-1.46 GHz split into channels of 7.63 kHz.The original angular resolution is in the range of~3’-~3.’8,and we combined all the data at a common resolution of 4’.The temperature scale of the total intensity and the spectral index from the in-band temperature-temperature plot are consistent with previous observations,which validates the data calibration and map-making procedures.The rms sensitivity for the band-averaged total-intensity map is about 20 mK in brightness temperature,which is at the level of confusion limit.For the first time,we apply rotation measure(RM)synthesis to the Cygnus Loop to obtain the polarization intensity and RM maps.The rms sensitivity for polarization is about 5 mK,far below the total-intensity confusion limit.We also obtained RMs of eight extragalactic sources,and demonstrate that the wide-band frequency coverage helps to overcome the ambiguity of RM determinations.
文摘Objective: Aberrant expression of ten-eleven translocation 1 (TET1) plays a critical role in tumor development and progression. We systematically summarized the latest research progress on the role and mechanisms of TET1 in cancer biology. Data Sources: Relevant articles published in English from 1980 to April 2016 were selected from the PubMed database. Tile terms "'ten-eleven translocation 1," "'SmC," '5hmC," 'microRNA,'" "hypoxia," and "'embryonic stem cell'" were used tbr the search. Study Selection: Articles focusing on the role and mechanism ofTETI in tumor were reviewed, including clinical and basic research articles. Results: TET proteins, the key enzymes converting 5-methylcytosine to 5-hydroxymethylcytosine, play vital roles in DNA demethylation regulation. Recent studies have shown that loss of TETI is associated with tumorigenesis and can be used as a potential biomarker for cancer therapy, which indicates that TETI serves as tumor suppressor gene. Moreover, besides its dioxygenase activity, TET1 could induce epithelial-mesenchymal transition and act as a coactivator to regulate gene transcription, such as developmental regulator in embryonic stem cells (ESCs) and hypoxia-responsive gene in cancer. The regulation of TETl is also correlated with microRNA in a posttranscriptional modification process. Hence, it is complex but critical to coaprehend the mechanisms of TETI in the biology of ESCs and cancer. Conclusions: TET I not only serves as a demethylation enzyme but also plays multiple roles during tumorigenesis and progression. More studies should be carried out to elucidate the exact mechanisms of TETI and its associations with cancer betbre considering it as a therapeutic tool.
基金supported by the Fundamental Research Funds for the Central Universities (No.11612603)the Science and Technology Planning Project of Zhongshan City (No.2013A3FC0325)
文摘One new stenine-type alkaloid, tuberostemonine D (1), together with five known stenine-type alkaloids (2-6) and two known stemoninine-type alkaloids (7 and 8), were isolated from the roots of Stemona tuberosa. Their structures were elucidated by extensive spectroscopic methods (IR, UV, MS, 1D and 2D NMR), and the structure of I was further confirmed by X-ray diffraction analysis. First simultaneous isolation ofstenine- and stemoninine-type alkaloids not only added a new chemical type and increased the chemical diversity of Stemona tuberosa, but also provided chemotaxonomic clues for the close relationship between genera Stemona and Stichoneuron, and favored retaining them in the same family.
基金NSFC (No. 21202006)FRFCU (No. FRF-TP14-015A2) for financial supports and Super-computer Center of Shanghai and Shenzhen for technical supports
文摘As the rate-determining step in native chemical ligation reactions, the thiol–thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol–thioester exchange step. According to the calculation results, the thiol–thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect(i.e. conjugation and hyper-conjugation effects) becomes important when the steric hindrance is insignificant.