Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent ye...Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent years, which causes watery diarrhea in newborn piglets. The host inflammatory responses to PEAV and its metabolic regulation mechanisms remain unclear, and no antiviral studies have been reported. Therefore, we investigated the pathogenic mechanism and antiviral drugs of PEAV. The transcriptomic analysis of PEAV-infected host cells revealed that PEAV could upregulate lipid metabolism pathways. In lipid metabolism, steady-state energy processes, which can be mediated by lipid droplets(LDs), are the main functions of organelles. LDs are also important in viral infection and inflammation. In infected cells, PEAV increased LD accumulation, upregulated NF-κB signaling, promoted the production of the inflammatory cytokines IL-1β and IL-8, and induced cell death. Inhibiting LD accumulation with a DGAT-1 inhibitor significantly inhibited PEAV replication, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. The NF-κB signaling pathway inhibitor BAY11-7082 significantly inhibited LD accumulation and PEAV replication. Metformin hydrochloride also exerted anti-PEAV effects and significantly inhibited LD accumulation, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. LD accumulation in the lipid metabolism pathway therefore plays an important role in the replication and pathogenesis of PEAV, and metformin hydrochloride inhibits LD accumulation and the inflammatory response to exert anti-PEAV activity and reducing pathological injury. These findings contribute new targets for developing treatments for PEAV infections.展开更多
The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Tibet,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of...The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Tibet,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of focused Cherenkov detectors.Its objective is to observe transient sources such as gamma-ray bursts and the counterparts of gravitational waves.This study aims to utilize the latest AI technology to enhance the sensitivity of HADAR experiments.Training datasets and models with distinctive creativity were constructed by incorporating the relevant physical theories for various applications.These models can determine the type,energy,and direction of the incident particles after careful design.We obtained a background identification accuracy of 98.6%,a relative energy reconstruction error of 10.0%,and an angular resolution of 0.22°in a test dataset at 10 TeV.These findings demonstrate the significant potential for enhancing the precision and dependability of detector data analysis in astrophysical research.By using deep learning techniques,the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and H.E.S.S.at energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher energies.In addition,our experiment offers a new approach for dealing with strongly connected,scattered data.展开更多
The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with t...The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with the strain-based isotropic damage theory to uncover the cooling-dominated cracking behaviors through three typical cases,i.e.coal reservoirs containing a wellbore,a primary fracture,and a natural fracture network,respectively.The progressive cracking processes,from thermal fracture initiation,propagation or cessation,deflection,bifurcation to multi-fracture interactions,can be well captured by the numerical model.It is observed that two hierarchical levels of thermal fractures are formed,in which the number of shorter thermal fractures consistently exceeds that of the longer ones.The effects of coal properties related to thermal stress levels and thermal diffusivity on the fracture morphology are quantified by the fracture fractal dimension and the statistical fracture number.The induced fracture morphology is most sensitive to changes in the elastic modulus and thermal expansion coefficient,both of which dominate the complexity of the fracture networks.Coal reservoir candidates with preferred thermal-mechanical properties are also recommended for improving the stimulation effect.Further findings are that there exists a critical injection temperature and a critical in-situ stress difference,above which no thermal fractures would be formed.Preexisting natural fractures with higher density and preferred orientations are also essential for the formation of complex fracture networks.The obtained results can provide some theoretical support for cryogenic fracturing design in coal reservoirs.展开更多
Ground-based arrays of imaging atmospheric Cherenkov telescopes(IACTs)are the most sensitiveγ-ray detectors for energies of approximately 100 Ge V and above.One such IACT is the High Altitude Detection of Astronomica...Ground-based arrays of imaging atmospheric Cherenkov telescopes(IACTs)are the most sensitiveγ-ray detectors for energies of approximately 100 Ge V and above.One such IACT is the High Altitude Detection of Astronomical Radiation(HADAR)experiment,which uses a large aperture refractive water lens system to capture atmospheric Cherenkov photons(i.e.,the imaging atmospheric Cherenkov technique).The telescope array has a low threshold energy and large field of view,and can continuously scan the area of the sky being observed,which is conducive to monitoring and promptly responding to transient phenomena.The process ofγ-hadron separation is essential in very-high-energy(>30 Ge V)γ-ray astronomy and is a key factor for the successful utilization of IACTs.In this study,Monte Carlo simulations were carried out to model the response of cosmic rays within the HADAR detectors.By analyzing the Hillas parameters and the distance between the event core and the telescope,the distinction between air showers initiated byγ-rays and those initiated by cosmic rays was determined.Additionally,a Quality Factor was introduced to assess the telescope’s ability to suppress the background and to provide a more effective characterization of its performance.展开更多
We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemet...We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemetallicity relation,integrals of motion,action space and the GC orbits to identify the GCs as either formed in situ(Bulge and Disk) or ex situ(via accretion).We find that 45.3% have formed in situ,while 38.4% may be related to known merger events:Gaia-Sausage-Enceladus,the Sagittarius dwarf galaxy,the Helmi streams,the Sequoia galaxy and the Kraken galaxy.We also further identify three new sub-structures associated with the Gaia-Sausage-Enceladus.The remaining 16.3% of GCs are unrelated to the known mergers and thought to be from small accretion events.We select 46 GCs which have radii 8.0 <r<37.3 kpc and obtain the anisotropy parameter β=0.315_(-0.049)^(+0.055),which is lower than the recent result using the sample of GCs in Gaia Data Release 2,but still in agreement with it by considering the error bar.By using the same sample,we obtain the MW mass inside the outermost GC as M(<37.3 kpc)=0.423_(-0.02)^(+0.02)×10^(12)M_(⊙),and the corresponding M_(200)=1.11_(-0.18)^(+0.25)×10^(12)M_(⊙).The estimated mass is consistent with the results in many recent studies.We also find that the estimated β and mass depend on the selected sample of GCs.However,it is difficult to determine whether a GC fully traces the potential of the MW.展开更多
Being one of the most fundamental physical parameter of astronomical objects,mass plays a vital role in the study of exoplanets,including their temperature structure,chemical composition,formation,and evolution.Howeve...Being one of the most fundamental physical parameter of astronomical objects,mass plays a vital role in the study of exoplanets,including their temperature structure,chemical composition,formation,and evolution.However,nearly a quarter of the known confirmed exoplanets lack measurements of their masses.This is particularly severe for those discovered via the radial velocity(RV)technique,which alone could only yield the minimum mass of planets.In this study,we use published RV data combined with astrometric data from a cross-calibrated Hipparcos-Gaia Catalog of Accelerations to jointly constrain the masses of 115 RV-detected substellar companions,by conducting full orbital fits using the public tool orvara.Among them,9 exoplanets with M_(p)sini<13.5M_(Jup)are reclassified to the brown dwarf(BD)regime,and 16 BD candidates(13.5≤Mp sini<80M_(Jup))turn out to be low-mass M dwarfs.We point out the presence of a transition in the BD regime as seen in the distributions of host star metallicity and orbital eccentricity with respect to planet masses.We confirm the previous findings that companions with masses below 42.5 M_(Jup)might primarily form in the protoplanetary disk through core accretion or disk gravitational instability,while those with masses above 42.5 M_(Jup)formed through the gravitational instability of a molecular cloud like stars.Selection effects and detection biases,which may affect our analysis to some extent,are discussed.展开更多
Light is an important environmental signal that influences plant growth and development.Among the photoreceptors,phytochromes can sense red/far-red light to coordinate various biological processes.However,their functi...Light is an important environmental signal that influences plant growth and development.Among the photoreceptors,phytochromes can sense red/far-red light to coordinate various biological processes.However,their functions in strawberry are not yet known.In this study,we identified an EMS mutant,named P8,in woodland strawberry(Fragaria vesca)that showed greatly increased plant height and reduced anthocyanin content.Mapping-by-sequencing revealed that the causal mutation in FvePhyB leads to premature termination of translation.The light treatment assay revealed that FvePhyB is a bona fide red/far-red light photoreceptor,as it specifically inhibits hypocotyl length under red light.Transcriptome analysis showed that the FvePhyB mutation affects the expression levels of genes involved in hormone synthesis and signaling and anthocyanin biosynthesis in petioles and fruits.The srl mutant with a longer internode is caused by a mutation in the DELLA gene FveRGA1(Repressor of GA1)in the gibberellin pathway.We found that the P8 srl double mutant has much longer internodes than srl,suggesting a synergistic role of FvePhyB and FveRGA1 in this process.Taken together,these results demonstrate the important role of FvePhyB in regulating plant architecture and anthocyanin content in woodland strawberry.展开更多
Dear Editor,We reported a case of a multidisciplinary therapy for late recovered facial paralysis 2y after the initial diagnosis.Facial paralysis has an incidence of 20-30 people out of 100000 per year,and up to 1 in ...Dear Editor,We reported a case of a multidisciplinary therapy for late recovered facial paralysis 2y after the initial diagnosis.Facial paralysis has an incidence of 20-30 people out of 100000 per year,and up to 1 in 60 people will be affected during their life time[1].展开更多
Objective: To evaluate the effect of early intrajejunalnutrition in attenuating bacterial and/or endotoxintranslocation and improving gut barrier function ofsevere acute pancreatitis (SAP) in dogs.Methods: 15 dogs wer...Objective: To evaluate the effect of early intrajejunalnutrition in attenuating bacterial and/or endotoxintranslocation and improving gut barrier function ofsevere acute pancreatitis (SAP) in dogs.Methods: 15 dogs were divided into parenteral nutrition(PN) group(7 dogs)and early intrajejunal nutrition(EIN) group(8). EIN was delivered nutrients via a nee-dle jejunostomy catheter feeding at 48h after operation.SAP model was induced by injecting 1 ml/kg of com-bined solution of 5% sodium taurocholate and 8000-10000 BAEE units trypsin/ml into the pancreas via thepancreatic duct. Systemic blood samples were ob-tained before and 1, 3, 5, 7 d following SAP, and culturedby aerobic as well as anaerobic bacterial growth. Systemicplasma and portal vein endotoxin levels were quantifiedby the chromogenic limulus amebocyte lysate (LAL)technique. Portal vein blood and specimens of tissuefrom the mesenteriolum and mesocolon lymph nodes,lung, pulmonary portal lymph nodes, pancreatitis tissueand periopancreas tissue were adopted before the experi-ment was finished. Aliquots of the homogenata were cul-tured as blood mentioned above to determine the magnitudeof the bacteria DNA, protein and the villi, the thickness ofmucosa, and the whole bowel wall of the ileum and trans-verse colon were measured.Results: The study showed that the levels of systemicplasma endotoxin and the magnitude of bacterialtranslocation to the portal and systemic blood and dis-tant organ were reduced significantly in the EINgroup as compared with the TPN group. The contentsof protein and DNA, the height of villi, the thicknessof mucosa and whole bowel wall of the ileum andtransverse colon in the EIN group were higher thanthose in the PN group.Conclusion: Our results suggested that EIN is safe andeffective to be adopted by intrajejunal delivery of nu-trients in SAP, decreases the occurrence of gut bacterialtranslocation, and improves the gut barrier function.展开更多
In situ forming hydrogels with simple sol–gel transition are more practicable as injectable hydrogels for drug delivery and tissue regeneration. State-of-the-art in situ gelling systems can easily and efficiently be ...In situ forming hydrogels with simple sol–gel transition are more practicable as injectable hydrogels for drug delivery and tissue regeneration. State-of-the-art in situ gelling systems can easily and efficiently be formed by different mechanisms in situ. Chitosan is a kind of natural polysaccharide that is widely exploited for biomedical applications due to its good biocompatibility, low immunogenicity and specific biological activities. Chitosan-based in situ gelling systems have already gained much attention as smart biomaterials in the development of several biomedical applications, such as for drug delivery systems and regeneration medicine. Herein, we review the typical in situ gelling systems based on chitosan and mechanisms involved in hydrogel forming, and report advances of chitosan-based in situ gels for the applications in drug delivery and tissue regeneration. Finally, development prospects of in situ forming hydrogels based on chitosan are also discussed in brief.展开更多
A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The...A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The rabbits were treated with anodal block stimulation at sacral anterior roots for 4 weeks. Electrical stimulation of sacral anterior roots improved urodynamic parameters of neurogenic bladder in rabbit models of complete spinal cord injury, effectively promoted urinary function, and relieved urinary retention. Immunohistochemistry results showed that a balance was achieved among expression of muscarinic receptor subunits M2, M3, ATP-gated ion channel P2X3 receptors, and 132-adrenergic receptor, and nerve growth factor expression decreased. These results suggested that long-term sacral anterior root stimulation of anodal block could'be used to treat neurogenic bladder in a rabbit model of complete spinal cord injury.展开更多
Idealized numerical simulations are conducted in this study to comparatively investigate the characteristics of the stratiform sector in the outer rainbands of tropical cyclones(TCs)in lower-and upper-layer vertical w...Idealized numerical simulations are conducted in this study to comparatively investigate the characteristics of the stratiform sector in the outer rainbands of tropical cyclones(TCs)in lower-and upper-layer vertical wind shear(VWS)with moderate magnitude.Consistent with the results in previous studies,the outer rainband stratiform sector of the TCs simulated in both experiments is generally located downshear left.Upper-layer VWS tends to produce stronger asymmetric outflow at upper levels in the downshear-left quadrant than lower-layer shear.This stronger asymmetric outflow transports more water vapor radially outward from the inner core to the outer core at upper levels in the downshear-left quadrant in the upper-layer shear experiment.More depositional growth of both graupel and cloud ice thus occurs downshear left in upper layers in the outer core,yielding more diabatic heating and stronger upward motions,particularly in the stratiformdominated part of the stratiform sector in the upper-layer shear experiment.Resultingly,a better-organized stratiform sector in the outer rainbands is found in the upper-layer VWS experiment than in the lower-layer VWS experiment.The diabatic heating associated with the stratiform sector produces strong midlevel outflow on the radially inward side of,and weak midlevel inflow on the radially outward side of,the heating core,with lower-level inflow beneath the midlevel outflow and upper-level inflow above.The upper-layer VWS tends to produce a deeper asymmetric inflow layer in the outer rainband stratiform sector,with more significant lower-level inflow and tangential jets in the upper-layer VWS experiment.展开更多
Osteoporosis(OP)is a common skeletal disease involving low bone mineral density(BMD)that often leads to fragility fracture,and its development is affected by multiple cellular pathologies and associated with marked ep...Osteoporosis(OP)is a common skeletal disease involving low bone mineral density(BMD)that often leads to fragility fracture,and its development is affected by multiple cellular pathologies and associated with marked epigenetic alterations of osteogenic genes.Proper physical exercise is beneficial for bone health and OP and reportedly possesses epigenetic modulating capacities;however,whether the protective effects of exercise on OP involve epigenetic mechanisms is unclear.Here,we report that epigenetic derepression of nuclear factor erythroid derived 2-related factor-2(Nrf2),a master regulator of oxidative stress critically involved in the pathogenesis of OP,mediates the significant osteoprotective effects of running exercise(RE)in a mouse model of OP induced by ovariectomy.We showed that Nrf2 gene knockout(Nfe2l2^(−/−))ovariectomized mice displayed a worse BMD reduction than the controls,identifying Nrf2 as a critical antiosteoporotic factor.Further,femoral Nrf2 was markedly repressed with concomitant DNA methyltransferase(Dnmt)1/Dnmt3a/Dnmt3b elevations and Nrf2 promoter hypermethylation in both patients with OP and ovariectomized mice.However,daily 1-h treadmill RE significantly corrected epigenetic alterations,recovered Nrf2 loss and improved the femur bone mass and trabecular microstructure.Consistently,RE also normalized the adverse expression of major osteogenic factors,including osteoblast/osteoclast markers,Nrf2 downstream antioxidant enzymes and proinflammatory cytokines.More importantly,the RE-conferred osteoprotective effects observed in the wild-type control mice were largely abolished in the Nfe2l2^(−/−)mice.Thus,Nrf2 repression due to aberrant Dnmt elevation and subsequent Nrf2 promoter hypermethylation is likely an important epigenetic feature of the pathogenesis of OP,and Nrf2 derepression is essential for the antiosteoporotic effects of RE.展开更多
The sacral nerve anterior root consists of parasympathetic nerves(dominating urinary bladder detrusor)and somatic motor nerves(dominating urethral sphincter),and electrical stimulation to the sacral nerve anterior...The sacral nerve anterior root consists of parasympathetic nerves(dominating urinary bladder detrusor)and somatic motor nerves(dominating urethral sphincter),and electrical stimulation to the sacral nerve anterior root induces simultaneous contraction of the bladder detrusor and urethral sphincter.Accordingly,urethral pressure exceeds intravesical pressure,resulting in little or no urination,kidney damage,and trembling of lower limbs due to high intravesical pressure.In the present study,sacral nerve posterior roots were transected in a spastic bladder rabbit model,followed by three-pole electrode and long-pulse electrical stimulation to the sacral anterior root.Intravesical and urethral pressures were simultaneously measured to verify the feasibility of anode inhibition to the sacral anterior root following induced detrusor contraction.As stimulus intensity increased,somatic motor nerves were increasingly inhibited; with a stimulus pulse width of 300 μs and stimulus current of 1.05 mA,urethral pressure was zero and average intravesical pressure was 3.84 kPa.In addition,detrusor contraction was displayed,and lower extremity trembling was significantly reduced.Three-pole electrode and long-pulse electrical stimulation to the sacral nerve anterior root induced detrusor contraction and inhibited low extremity trembling under electrical stimulation.展开更多
基金funded by the National Natural Science Foundation of China(32102646)the Natural Science Foundation of Guangdong Province,China(2020A1515110315)+1 种基金the Start-up Research Project of Maoming Laboratory,China(2021TDQD002)the China Agriculture Research System of MOF and MARA(cars-35)。
文摘Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent years, which causes watery diarrhea in newborn piglets. The host inflammatory responses to PEAV and its metabolic regulation mechanisms remain unclear, and no antiviral studies have been reported. Therefore, we investigated the pathogenic mechanism and antiviral drugs of PEAV. The transcriptomic analysis of PEAV-infected host cells revealed that PEAV could upregulate lipid metabolism pathways. In lipid metabolism, steady-state energy processes, which can be mediated by lipid droplets(LDs), are the main functions of organelles. LDs are also important in viral infection and inflammation. In infected cells, PEAV increased LD accumulation, upregulated NF-κB signaling, promoted the production of the inflammatory cytokines IL-1β and IL-8, and induced cell death. Inhibiting LD accumulation with a DGAT-1 inhibitor significantly inhibited PEAV replication, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. The NF-κB signaling pathway inhibitor BAY11-7082 significantly inhibited LD accumulation and PEAV replication. Metformin hydrochloride also exerted anti-PEAV effects and significantly inhibited LD accumulation, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. LD accumulation in the lipid metabolism pathway therefore plays an important role in the replication and pathogenesis of PEAV, and metformin hydrochloride inhibits LD accumulation and the inflammatory response to exert anti-PEAV activity and reducing pathological injury. These findings contribute new targets for developing treatments for PEAV infections.
文摘The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Tibet,China,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of focused Cherenkov detectors.Its objective is to observe transient sources such as gamma-ray bursts and the counterparts of gravitational waves.This study aims to utilize the latest AI technology to enhance the sensitivity of HADAR experiments.Training datasets and models with distinctive creativity were constructed by incorporating the relevant physical theories for various applications.These models can determine the type,energy,and direction of the incident particles after careful design.We obtained a background identification accuracy of 98.6%,a relative energy reconstruction error of 10.0%,and an angular resolution of 0.22°in a test dataset at 10 TeV.These findings demonstrate the significant potential for enhancing the precision and dependability of detector data analysis in astrophysical research.By using deep learning techniques,the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and H.E.S.S.at energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher energies.In addition,our experiment offers a new approach for dealing with strongly connected,scattered data.
基金funding support from the Natural Science Foundation of Sichuan,China(Grant No.2022NSFSC1227)the National Natural Science Foundation of China(Grant Nos.U1762216 and 51574270).
文摘The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives.In this paper,we develop a fully coupled thermo-elastic model in combination with the strain-based isotropic damage theory to uncover the cooling-dominated cracking behaviors through three typical cases,i.e.coal reservoirs containing a wellbore,a primary fracture,and a natural fracture network,respectively.The progressive cracking processes,from thermal fracture initiation,propagation or cessation,deflection,bifurcation to multi-fracture interactions,can be well captured by the numerical model.It is observed that two hierarchical levels of thermal fractures are formed,in which the number of shorter thermal fractures consistently exceeds that of the longer ones.The effects of coal properties related to thermal stress levels and thermal diffusivity on the fracture morphology are quantified by the fracture fractal dimension and the statistical fracture number.The induced fracture morphology is most sensitive to changes in the elastic modulus and thermal expansion coefficient,both of which dominate the complexity of the fracture networks.Coal reservoir candidates with preferred thermal-mechanical properties are also recommended for improving the stimulation effect.Further findings are that there exists a critical injection temperature and a critical in-situ stress difference,above which no thermal fractures would be formed.Preexisting natural fractures with higher density and preferred orientations are also essential for the formation of complex fracture networks.The obtained results can provide some theoretical support for cryogenic fracturing design in coal reservoirs.
基金supported by the Central Government Funds for Local Scientific and Technological Development(grant No.JDRC2023000009)Tibet University Postgraduate Students’High-Level Talent Training Plan Project(grant No.2021-GSP-S038)。
文摘Ground-based arrays of imaging atmospheric Cherenkov telescopes(IACTs)are the most sensitiveγ-ray detectors for energies of approximately 100 Ge V and above.One such IACT is the High Altitude Detection of Astronomical Radiation(HADAR)experiment,which uses a large aperture refractive water lens system to capture atmospheric Cherenkov photons(i.e.,the imaging atmospheric Cherenkov technique).The telescope array has a low threshold energy and large field of view,and can continuously scan the area of the sky being observed,which is conducive to monitoring and promptly responding to transient phenomena.The process ofγ-hadron separation is essential in very-high-energy(>30 Ge V)γ-ray astronomy and is a key factor for the successful utilization of IACTs.In this study,Monte Carlo simulations were carried out to model the response of cosmic rays within the HADAR detectors.By analyzing the Hillas parameters and the distance between the event core and the telescope,the distinction between air showers initiated byγ-rays and those initiated by cosmic rays was determined.Additionally,a Quality Factor was introduced to assess the telescope’s ability to suppress the background and to provide a more effective characterization of its performance.
基金supported by the Central Government Funds for Local Scientific and Technological Development(grant No.JDRC2023000009)supported by the Natural Science Foundation of Tibet Autonomous Region(grant No.XZ202401ZR0064)."。
基金support by the National Key R&D Program(No.2017YFA0402603)the Inter-government cooperation Flagship program(Grant No.2018YFE0120800)+2 种基金the National Natural Science Foundation of China(NSFC,Grant Nos.11773034 and 11633004)the Chinese Academy of Sciences(CAS)Strategic Priority Research Program XDA15020200the CAS Interdisciplinary Innovation Team(JCTD-2019-05)。
文摘We combine the kinematics of 159 globular clusters(GCs) provided by the Gaia Early Data Release 3(EDR3) with other observational data to classify the GCs,and to estimate the mass of the Milky Way(MW).We use the agemetallicity relation,integrals of motion,action space and the GC orbits to identify the GCs as either formed in situ(Bulge and Disk) or ex situ(via accretion).We find that 45.3% have formed in situ,while 38.4% may be related to known merger events:Gaia-Sausage-Enceladus,the Sagittarius dwarf galaxy,the Helmi streams,the Sequoia galaxy and the Kraken galaxy.We also further identify three new sub-structures associated with the Gaia-Sausage-Enceladus.The remaining 16.3% of GCs are unrelated to the known mergers and thought to be from small accretion events.We select 46 GCs which have radii 8.0 <r<37.3 kpc and obtain the anisotropy parameter β=0.315_(-0.049)^(+0.055),which is lower than the recent result using the sample of GCs in Gaia Data Release 2,but still in agreement with it by considering the error bar.By using the same sample,we obtain the MW mass inside the outermost GC as M(<37.3 kpc)=0.423_(-0.02)^(+0.02)×10^(12)M_(⊙),and the corresponding M_(200)=1.11_(-0.18)^(+0.25)×10^(12)M_(⊙).The estimated mass is consistent with the results in many recent studies.We also find that the estimated β and mass depend on the selected sample of GCs.However,it is difficult to determine whether a GC fully traces the potential of the MW.
基金supported by the National Key R&D Program of China Nos.2019YFA0405102 and 2019YFA0405502supported by the National Natural Science Foundation of China(NSFC,Grant Nos.12073044 and 11988101)。
文摘Being one of the most fundamental physical parameter of astronomical objects,mass plays a vital role in the study of exoplanets,including their temperature structure,chemical composition,formation,and evolution.However,nearly a quarter of the known confirmed exoplanets lack measurements of their masses.This is particularly severe for those discovered via the radial velocity(RV)technique,which alone could only yield the minimum mass of planets.In this study,we use published RV data combined with astrometric data from a cross-calibrated Hipparcos-Gaia Catalog of Accelerations to jointly constrain the masses of 115 RV-detected substellar companions,by conducting full orbital fits using the public tool orvara.Among them,9 exoplanets with M_(p)sini<13.5M_(Jup)are reclassified to the brown dwarf(BD)regime,and 16 BD candidates(13.5≤Mp sini<80M_(Jup))turn out to be low-mass M dwarfs.We point out the presence of a transition in the BD regime as seen in the distributions of host star metallicity and orbital eccentricity with respect to planet masses.We confirm the previous findings that companions with masses below 42.5 M_(Jup)might primarily form in the protoplanetary disk through core accretion or disk gravitational instability,while those with masses above 42.5 M_(Jup)formed through the gravitational instability of a molecular cloud like stars.Selection effects and detection biases,which may affect our analysis to some extent,are discussed.
基金This work was supported by the National Natural Science Foundation of China(32172539)the Fundamental Research Funds for the Central Universities(2662022YLPY002).
文摘Light is an important environmental signal that influences plant growth and development.Among the photoreceptors,phytochromes can sense red/far-red light to coordinate various biological processes.However,their functions in strawberry are not yet known.In this study,we identified an EMS mutant,named P8,in woodland strawberry(Fragaria vesca)that showed greatly increased plant height and reduced anthocyanin content.Mapping-by-sequencing revealed that the causal mutation in FvePhyB leads to premature termination of translation.The light treatment assay revealed that FvePhyB is a bona fide red/far-red light photoreceptor,as it specifically inhibits hypocotyl length under red light.Transcriptome analysis showed that the FvePhyB mutation affects the expression levels of genes involved in hormone synthesis and signaling and anthocyanin biosynthesis in petioles and fruits.The srl mutant with a longer internode is caused by a mutation in the DELLA gene FveRGA1(Repressor of GA1)in the gibberellin pathway.We found that the P8 srl double mutant has much longer internodes than srl,suggesting a synergistic role of FvePhyB and FveRGA1 in this process.Taken together,these results demonstrate the important role of FvePhyB in regulating plant architecture and anthocyanin content in woodland strawberry.
基金Supported by the National Natural Science Foundation of China (No.82000938,No.81900906,No.82000857)。
文摘Dear Editor,We reported a case of a multidisciplinary therapy for late recovered facial paralysis 2y after the initial diagnosis.Facial paralysis has an incidence of 20-30 people out of 100000 per year,and up to 1 in 60 people will be affected during their life time[1].
文摘Objective: To evaluate the effect of early intrajejunalnutrition in attenuating bacterial and/or endotoxintranslocation and improving gut barrier function ofsevere acute pancreatitis (SAP) in dogs.Methods: 15 dogs were divided into parenteral nutrition(PN) group(7 dogs)and early intrajejunal nutrition(EIN) group(8). EIN was delivered nutrients via a nee-dle jejunostomy catheter feeding at 48h after operation.SAP model was induced by injecting 1 ml/kg of com-bined solution of 5% sodium taurocholate and 8000-10000 BAEE units trypsin/ml into the pancreas via thepancreatic duct. Systemic blood samples were ob-tained before and 1, 3, 5, 7 d following SAP, and culturedby aerobic as well as anaerobic bacterial growth. Systemicplasma and portal vein endotoxin levels were quantifiedby the chromogenic limulus amebocyte lysate (LAL)technique. Portal vein blood and specimens of tissuefrom the mesenteriolum and mesocolon lymph nodes,lung, pulmonary portal lymph nodes, pancreatitis tissueand periopancreas tissue were adopted before the experi-ment was finished. Aliquots of the homogenata were cul-tured as blood mentioned above to determine the magnitudeof the bacteria DNA, protein and the villi, the thickness ofmucosa, and the whole bowel wall of the ileum and trans-verse colon were measured.Results: The study showed that the levels of systemicplasma endotoxin and the magnitude of bacterialtranslocation to the portal and systemic blood and dis-tant organ were reduced significantly in the EINgroup as compared with the TPN group. The contentsof protein and DNA, the height of villi, the thicknessof mucosa and whole bowel wall of the ileum andtransverse colon in the EIN group were higher thanthose in the PN group.Conclusion: Our results suggested that EIN is safe andeffective to be adopted by intrajejunal delivery of nu-trients in SAP, decreases the occurrence of gut bacterialtranslocation, and improves the gut barrier function.
文摘In situ forming hydrogels with simple sol–gel transition are more practicable as injectable hydrogels for drug delivery and tissue regeneration. State-of-the-art in situ gelling systems can easily and efficiently be formed by different mechanisms in situ. Chitosan is a kind of natural polysaccharide that is widely exploited for biomedical applications due to its good biocompatibility, low immunogenicity and specific biological activities. Chitosan-based in situ gelling systems have already gained much attention as smart biomaterials in the development of several biomedical applications, such as for drug delivery systems and regeneration medicine. Herein, we review the typical in situ gelling systems based on chitosan and mechanisms involved in hydrogel forming, and report advances of chitosan-based in situ gels for the applications in drug delivery and tissue regeneration. Finally, development prospects of in situ forming hydrogels based on chitosan are also discussed in brief.
文摘A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The rabbits were treated with anodal block stimulation at sacral anterior roots for 4 weeks. Electrical stimulation of sacral anterior roots improved urodynamic parameters of neurogenic bladder in rabbit models of complete spinal cord injury, effectively promoted urinary function, and relieved urinary retention. Immunohistochemistry results showed that a balance was achieved among expression of muscarinic receptor subunits M2, M3, ATP-gated ion channel P2X3 receptors, and 132-adrenergic receptor, and nerve growth factor expression decreased. These results suggested that long-term sacral anterior root stimulation of anodal block could'be used to treat neurogenic bladder in a rabbit model of complete spinal cord injury.
基金the National Key Research and Development Program of China(Grant No.2017YFC1501601)the Key Program of the Ministry of Science and Technology of China(Grant No.2017YFE0107700)the National Natural Science Foundation of China(Grant Nos.41875054,41730961,41730960,and 41775065).
文摘Idealized numerical simulations are conducted in this study to comparatively investigate the characteristics of the stratiform sector in the outer rainbands of tropical cyclones(TCs)in lower-and upper-layer vertical wind shear(VWS)with moderate magnitude.Consistent with the results in previous studies,the outer rainband stratiform sector of the TCs simulated in both experiments is generally located downshear left.Upper-layer VWS tends to produce stronger asymmetric outflow at upper levels in the downshear-left quadrant than lower-layer shear.This stronger asymmetric outflow transports more water vapor radially outward from the inner core to the outer core at upper levels in the downshear-left quadrant in the upper-layer shear experiment.More depositional growth of both graupel and cloud ice thus occurs downshear left in upper layers in the outer core,yielding more diabatic heating and stronger upward motions,particularly in the stratiformdominated part of the stratiform sector in the upper-layer shear experiment.Resultingly,a better-organized stratiform sector in the outer rainbands is found in the upper-layer VWS experiment than in the lower-layer VWS experiment.The diabatic heating associated with the stratiform sector produces strong midlevel outflow on the radially inward side of,and weak midlevel inflow on the radially outward side of,the heating core,with lower-level inflow beneath the midlevel outflow and upper-level inflow above.The upper-layer VWS tends to produce a deeper asymmetric inflow layer in the outer rainband stratiform sector,with more significant lower-level inflow and tangential jets in the upper-layer VWS experiment.
基金supported by research grants from the National Nature and Science Foundation of China(NSFC)Key Program(81730067)the NSFC General Program(81670762 and 81970577)the NSFC Major Project(81991514).
文摘Osteoporosis(OP)is a common skeletal disease involving low bone mineral density(BMD)that often leads to fragility fracture,and its development is affected by multiple cellular pathologies and associated with marked epigenetic alterations of osteogenic genes.Proper physical exercise is beneficial for bone health and OP and reportedly possesses epigenetic modulating capacities;however,whether the protective effects of exercise on OP involve epigenetic mechanisms is unclear.Here,we report that epigenetic derepression of nuclear factor erythroid derived 2-related factor-2(Nrf2),a master regulator of oxidative stress critically involved in the pathogenesis of OP,mediates the significant osteoprotective effects of running exercise(RE)in a mouse model of OP induced by ovariectomy.We showed that Nrf2 gene knockout(Nfe2l2^(−/−))ovariectomized mice displayed a worse BMD reduction than the controls,identifying Nrf2 as a critical antiosteoporotic factor.Further,femoral Nrf2 was markedly repressed with concomitant DNA methyltransferase(Dnmt)1/Dnmt3a/Dnmt3b elevations and Nrf2 promoter hypermethylation in both patients with OP and ovariectomized mice.However,daily 1-h treadmill RE significantly corrected epigenetic alterations,recovered Nrf2 loss and improved the femur bone mass and trabecular microstructure.Consistently,RE also normalized the adverse expression of major osteogenic factors,including osteoblast/osteoclast markers,Nrf2 downstream antioxidant enzymes and proinflammatory cytokines.More importantly,the RE-conferred osteoprotective effects observed in the wild-type control mice were largely abolished in the Nfe2l2^(−/−)mice.Thus,Nrf2 repression due to aberrant Dnmt elevation and subsequent Nrf2 promoter hypermethylation is likely an important epigenetic feature of the pathogenesis of OP,and Nrf2 derepression is essential for the antiosteoporotic effects of RE.
基金a grant for International Cooperation Project by Jilin Provincial Science and Technology Commission,No.20100735
文摘The sacral nerve anterior root consists of parasympathetic nerves(dominating urinary bladder detrusor)and somatic motor nerves(dominating urethral sphincter),and electrical stimulation to the sacral nerve anterior root induces simultaneous contraction of the bladder detrusor and urethral sphincter.Accordingly,urethral pressure exceeds intravesical pressure,resulting in little or no urination,kidney damage,and trembling of lower limbs due to high intravesical pressure.In the present study,sacral nerve posterior roots were transected in a spastic bladder rabbit model,followed by three-pole electrode and long-pulse electrical stimulation to the sacral anterior root.Intravesical and urethral pressures were simultaneously measured to verify the feasibility of anode inhibition to the sacral anterior root following induced detrusor contraction.As stimulus intensity increased,somatic motor nerves were increasingly inhibited; with a stimulus pulse width of 300 μs and stimulus current of 1.05 mA,urethral pressure was zero and average intravesical pressure was 3.84 kPa.In addition,detrusor contraction was displayed,and lower extremity trembling was significantly reduced.Three-pole electrode and long-pulse electrical stimulation to the sacral nerve anterior root induced detrusor contraction and inhibited low extremity trembling under electrical stimulation.