BACKGROUND Anastomotic leakage(AL)is a serious and challenging complication following low anterior resection(LAR)for low rectal cancer.This case series presents the successful management of AL in three patients using ...BACKGROUND Anastomotic leakage(AL)is a serious and challenging complication following low anterior resection(LAR)for low rectal cancer.This case series presents the successful management of AL in three patients using a combined approach of transanal opening of the intersphincteric space(TROPIS)surgery and adjuvant Kangfuxin liquid enema therapy.CASE SUMMARY Three male patients underwent laparoscopic LAR with diverting ileostomy for low rectal cancer.Case 1:A 39-year-old,presented with fever and abdominal distension 2 weeks after discharge.A digital rectal examination revealed partial anastomotic separation.Case 2:A 74-year-old,developed abdominal pain and fever on postoperative day 5,with fecal discharge through the pelvic drain,and computed tomography scan confirmed AL.Case 3:A 51-year-old,was asymptomatic but diagnosed with AL 1 week after discharge;despite 1 year of conservative management,the leakage failed to heal.All three patients were subsequently treated with TROPIS surgery combined with twice-daily Kangfuxin liquid enemas,resulting in complete resolution of AL in each case.CONCLUSION The combination of TROPIS and Kangfuxin enema appears to be a safe and effective approach for managing AL following LAR.This minimally invasive strategy offers a promising alternative to conventional surgical interventions.Further studies with larger cohorts are warranted to validate these findings.展开更多
Nitrogen is the primary nutrient limiting ecosystem productivity over most of the US. Although soil nitrogen content is important, knowledge about its spatial extent at the continental scale is limited. The objective ...Nitrogen is the primary nutrient limiting ecosystem productivity over most of the US. Although soil nitrogen content is important, knowledge about its spatial extent at the continental scale is limited. The objective of this study was to estimate net nitrogen mineralization for the conterminous US (CONUS) using an empirical modeling approach by scaling up site level measurements. Net nitrogen mineralization and total soil nitrogen data across the CONUS were obtained from three different ecosystems: low elevation forests, high elevation forests, and grasslands. Equations to predict net nitrogen mineralization were developed through stepwise linear regression using total Kjeldahl nitrogen, air temperature, precipitation, and nitrogen deposition as predictor variables for four categories: low elevation high temperature forests (coefficient of determination, R2 = 0.83), low elevation low temperature forests (R2 = 0.74), high elevation forests (R2 = 0.80), and grasslands (R2 = 0.88). A map of net nitrogen mineralization was developed in GIS using these equations and national-scale databases for the CONUS. The result shows that net nitrogen mineralization varies widely across the US. Grasslands were predicted to have the lowest net nitrogen mineralization, while low elevation forests in the east had the highest. Mean values were 14.3 kg·ha-1·yr-1 for grasslands, 22.6 kg·ha-1·yr-1 for high elevation forests, 58 kg·ha-1·yr-1 for low elevation low temperature forests, and 82.9 kg·ha-1·yr-1 for low elevation high temperature forests. This continental scale estimation of net nitrogen mineralization provides a means of comparing net nitrogen mineralization across regions, and the databases developed from this study are useful for accounting for nitrogen limitations in large scale ecosystem modeling.展开更多
Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population siz...Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population size and distribution of the Black-necked Crane(Grus nigricollis)in the Yarlung Zangbo River Basin(YZRB)from 10 to 29 January 2022,and predicted the current potentially suitable habitat distribution and its effective factors using the Max Ent model.A total of 9337 wintering Black-necked Cranes were recorded in the YZRB in 2022,76.58%of which were primarily found in Lhunzub,Samzhubze,Namling,and Lhaze.Compared to 2018,the crane population has exhibited a notable decline in Samzhubze and Taktse,likely due to farmland plowing,winter irrigation,changes in agricultural practices,road construction and hydraulic projects.The crane population within various counties exhibited a significant positive correlation with the suitable habitat area(r=0.70,P=0.002,n=17).We also found that the currently suitable habitat area covered 17,204 km~2,of which only 3244 km~2(18.86%)was effectively protected at the national level,which was predominantly distributed in farmland and rangeland habitats characterized by gentle slopes,altitudes not exceeding 4500 m,and proximity to human settlements along rivers,where suitable isothermal values(51)and less seasonal precipitation(20 mm)prevail.Our study will be helpful for formulating reasonable conservation strategies to protect the core population of this threatened highland flagship species.展开更多
Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this proble...Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this problem,the traditional particle tracking velocimetry method based on an optical flow was improved.The level set segmentation algorithm was used to obtain the boundary contour of the region with large velocity gradient changes,and the non-uniform flow field was divided into regions according to the boundary contour to obtain sub-regions with uniform velocity distribution.The particle tracking velocimetry method based on optical flow was used to measure the granular flow velocity in each sub-region,thus avoiding the problem of granular flow distribution.The simulation results show that the measurement accuracy of this method is approximately 10%higher than that of traditional methods.The method was applied to a velocity measurement experiment on dense granular flow in silos,and the velocity distribution of the granular flow was obtained,verifying the practicality of the method in granular flow fields.展开更多
Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were ...Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were generat-ed with internal excitation by multiphoton photolysis of CHBr_(3)at 248 nm,and its rotational temperature was found to relax to the flow temperature in a few microseconds by colliding with bath gas.The relaxation rate coefficients for CH(X^(2)Π,v=0)radical in He,Ar,and N_(2)flow were obtained by time-resolved laser-induced fluorescence measurements,ranging from 10^(-12)cm^(3)·molecule^(-1)·s^(-1)to 10^(-11)cm^(3)·molecule^(-1)·s^(-1).The N_(2)flow exhibits the highest relax-ation rate for CH(X^(2)Π)radical due to its additional rovibrational levels,which allow for more efficient energy dissipation during collisions compared to monoatomic gases.The Ar flow shows a larger relaxation rate than He flow due to its greater polarizability and stronger long-range interaction with the CH(X^(2)Π)radical.展开更多
Hepatitis B virus(HBV) infection is one of the most serious and prevalent viral diseases in the world. Although several anti-HBV drugs have been used clinically, their side and adverse effects limit treatment efficacy...Hepatitis B virus(HBV) infection is one of the most serious and prevalent viral diseases in the world. Although several anti-HBV drugs have been used clinically, their side and adverse effects limit treatment efficacy. Therefore, it is necessary to identify novel potential anti-HBV agents. The flavonol quercetin has shown activity against some retroviruses, but its effect on HBV remains unclear. In the present study, quercetin was incubated with Hep G2.2.15 cells, as well as Hu H-7 cells transfected with an HBV plasmid. Quercetin was shown to significantly reduce Hepatitis B surface antigen(HBs Ag) and Hepatitis B e antigen(HBe Ag), secretion and HBV genomic DNA levels in both cell lines. In addition, co-incubation with lamivudine(3TC), entecavir(ETV), or adefovir(Ade) further enhanced the quercetin-induced inhibition of HBV replication. This inhibition was partially associated with decreased heat shock proteins and HBV transcription levels. The results indicate that quercetin inhibited HBV antigen secretion and genome replication in human hepatoma cell lines, which suggests that quercetin may be a potentially effective anti-HBV agent.展开更多
Several indices and simple empirical models and ratios of single band from pre-and post-fire Landsat images have been developed to estimate and/or map burn severity.However,these models and indices are usually site-,t...Several indices and simple empirical models and ratios of single band from pre-and post-fire Landsat images have been developed to estimate and/or map burn severity.However,these models and indices are usually site-,time-and vegetation-dependent and their applications are limited.The Daxing'an Mountains range has the largest forested area in China and is prone to wildfires.Whether or not the existing models can effectively characterize the burn severity over a large region is unclear.In this study,we used the orthogonal signal correction method based on partial least squares regression(PLSR)to select those variables that better interpret the variance of burn severity.A new index and other commonly used indices were used to construct a new,multivariate PLSR model which was compared with the popular single variable models,according to three assessment indices:relative root mean square error(RMSE%),relative bias(R E%)and Nash–Sutcliffe efficiency(NSE%).The results indicate that the multivariate PLSR model performed better than the other single variable models with higher NSE%(68.2%vs.67.8%)and less RE%(3.7%vs.-8.7%),while achieving almost the same R MSE%.We also discuss the spectral characteristics of the four selected variables for constructing the multivariate PLSR model and their correlation with the field burn severity data.The new model developed from this study should help to better understand the patterns of forest burn severity and assist in vegetation restoration efforts in the region.展开更多
A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints ...A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.展开更多
The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and re...The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and related radiometric dating.A new species of angiospermous fossil plant.Platanus heilongjiangensis sp.nov.,from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2±1.7 Ma.indicating that the Upper Houshigou Formation is of Cenomanian age.This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation,but also shows that Platanus flourished in the early Late Cretaceous floras of the region.This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.展开更多
BACKGROUND Glioblastoma is the most common type of brain tumor and is invariably fatal,with a mean survival time of 8-15 mo for recently diagnosed tumors,and a 5-year survival rate of only 7.2%.The standard treatment ...BACKGROUND Glioblastoma is the most common type of brain tumor and is invariably fatal,with a mean survival time of 8-15 mo for recently diagnosed tumors,and a 5-year survival rate of only 7.2%.The standard treatment for newly diagnosed glioblastoma includes surgery followed by concurrent chemoradiotherapy and further adjuvant temozolomide.However,the prognosis remains poor and longterm survival is rare.This report aimed to demonstrate a new therapeutic strategy for the treatment of glioblastoma.CASE SUMMARY A patient was referred to the Department of Neurosurgery with an intracranial space-occupying lesion with a maximum diameter of approximately 5 cm.The tumor was compressing functional areas,and the patient accordingly underwent partial resection and concurrent chemoradiotherapy.The imaging and pathological findings were consistent with a diagnosis of glioblastoma with oligodendroglioma differentiation(World Health Organization IV).The patient was finally diagnosed with glioblastoma.However,the patient discontinued treatment due to intolerable side effects,and was prescribed Kangliu pill(KLP)7.5 g three times/d,which he has continued to date.Significant shrinkage of the tumor(maximum diameter reduced from about 3.5 to about 2 cm)was found after 3 mo of KLP therapy,and the tumor was further reduced to about 1 cm after 3 years.The patient’s symptoms of headache,limb weakness,and left hemiplegia were relieved,with no side effects.CONCLUSION KLP has been a successful intervention for glioblastoma, and the current caseindicates that traditional Chinese medicine may offer effective alternativetherapies for glioblastoma.展开更多
An early Norian flora from the Partizansk River Basin of Primorye, Far-East of Russia, is described in detail for the first time, in which over 25 taxa are reported. The flora is dominated by cycadoalean, bennettitale...An early Norian flora from the Partizansk River Basin of Primorye, Far-East of Russia, is described in detail for the first time, in which over 25 taxa are reported. The flora is dominated by cycadoalean, bennettitalean and coniferous plants, associated with a lot of ferns and czekanowskialean plants, and with a few ginkgoalean. In floristic characteristics, the flora can be well comparable with Late Triassic Mongugai flora of southwestern Primorye and its neighboring Tianqiaoling flora of eastern Jilin, China, as well with the Yamanoi and Nariwa floras from southwestern Japan. As the plant-bearing strata are sandwiched in the lower Norian marine beds yielding marine fauna, the age of the Partizansk flora is well evidenced as the early Norian. Paleophytogeographically, the flora appears to be in the ecotone of the Medio-Triassic and Arcto-Triassic floristic regions in Eurasia, and indicates probably warm temperate or subtropic vegetation in nature. Four new species are reported in this paper, including Ctenis elegantus sp. nov, Ixostrobus pacificus sp. nov., Elatocladus elegantus sp. nov. and E. prynadae sp. nov.展开更多
The ultraviolet （UV） photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236-254 nm using the high-n Rydberg-atom time-of-flight （HRTOF） technique. The H-atom photofragment...The ultraviolet （UV） photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236-254 nm using the high-n Rydberg-atom time-of-flight （HRTOF） technique. The H-atom photofragment yield spectrum of the 1-pentyl radical shows a broad UV absorption feature peaking near 245 nm, similar to the 2pz→3s absorption bands of ethyl and n-propyl. The center-of-mass translational energy distribution, P（ET）, of the H＋CsH10 product channel is bimodal, with a slow peak at -5 kcal/mol and a fast peak at -50 kcal/mol. The fraction of the average translational energy release in the total available energy, （fT）, is 0.30, with those of the slow and fast components being 0.13 and 0.58, respectively. The slow component has an isotropic product angular distribution, while the fast component is anisotropic with an anisotropy parameter -0.4. The bimodal translational energy and angular distributions of the H＋C5H10 products indicate two H-atom elimination channels in the photodissociation of 1-pentyl： （i） a direct, prompt dissociation from the electronic excited state and/or the repulsive part of the ground electronic state potential energy surface; and （ii） a unimolecular dissociation of internally hot radical in the ground electronic state after internal conversion from the electronic excited state.展开更多
Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the...Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.展开更多
Sleep is essential to the normal psychological and physiological activities of the human body.Increasing evidence indicates that sleep deprivation is associated with the occurrence,development,and poor treatment effec...Sleep is essential to the normal psychological and physiological activities of the human body.Increasing evidence indicates that sleep deprivation is associated with the occurrence,development,and poor treatment effects of various arrhythmias.Sleep deprivation affects not only the peripheral nervous system but also the central nervous system,which regulates the occurrence of arrhythmias.In addition,sleep deprivation is associated with apoptotic pathways,mitochondrial energy metabolism disorders,and immune system dysfunction.Although studies increasingly suggest that pathological sleep patterns are associated with various atrial and ventricular arrhythmias,further research is needed to identify specific mechanisms and recommend therapeutic interventions.This review summarizes the findings of sleep deprivation in animal experiments and clinical studies,current challenges,and future research directions in the field of arrhythmias.展开更多
The impacts of hurricane disturbance and climate variability on carbon dynamics in a coastal forested wetland in South Carolina of USA were simulated using the Forest-DNDC model with a spatially explicit approach. The...The impacts of hurricane disturbance and climate variability on carbon dynamics in a coastal forested wetland in South Carolina of USA were simulated using the Forest-DNDC model with a spatially explicit approach. The model was validated using the measured biomass before and after Hurricane Hugo and the biomass inventories in 2006 and 2007, showed that the Forest- DNDC model was applicable for estimating carbon dynamics with hurricane disturbance. The simulated results indicated that Hurricane Hugo in 1989 substantially influenced carbon storage immediately after the disturbance event. The simulated net ecosystem exchange (NEE) for the 58-year period (1950-2007) indicated that the hurricane reduced CO2 sequestration due primarily to the increased decomposition of a large amount of litter and woody debris, including fallen trees (over 80% of pre-hurricane trees), debris and branches, and dead roots. The inter-annual fluctuation of soil CO2 flux showed that the climate variability interfered substantially soil carbon dynamics in the forest. The results showed that there were substantial spatial and temporal differences in CO2 flux (3.2 - 4.8 Mg·C·ha–1) and wood biomass due to the differences in physical and biogeochemical characteristics in the forest.展开更多
文摘BACKGROUND Anastomotic leakage(AL)is a serious and challenging complication following low anterior resection(LAR)for low rectal cancer.This case series presents the successful management of AL in three patients using a combined approach of transanal opening of the intersphincteric space(TROPIS)surgery and adjuvant Kangfuxin liquid enema therapy.CASE SUMMARY Three male patients underwent laparoscopic LAR with diverting ileostomy for low rectal cancer.Case 1:A 39-year-old,presented with fever and abdominal distension 2 weeks after discharge.A digital rectal examination revealed partial anastomotic separation.Case 2:A 74-year-old,developed abdominal pain and fever on postoperative day 5,with fecal discharge through the pelvic drain,and computed tomography scan confirmed AL.Case 3:A 51-year-old,was asymptomatic but diagnosed with AL 1 week after discharge;despite 1 year of conservative management,the leakage failed to heal.All three patients were subsequently treated with TROPIS surgery combined with twice-daily Kangfuxin liquid enemas,resulting in complete resolution of AL in each case.CONCLUSION The combination of TROPIS and Kangfuxin enema appears to be a safe and effective approach for managing AL following LAR.This minimally invasive strategy offers a promising alternative to conventional surgical interventions.Further studies with larger cohorts are warranted to validate these findings.
文摘Nitrogen is the primary nutrient limiting ecosystem productivity over most of the US. Although soil nitrogen content is important, knowledge about its spatial extent at the continental scale is limited. The objective of this study was to estimate net nitrogen mineralization for the conterminous US (CONUS) using an empirical modeling approach by scaling up site level measurements. Net nitrogen mineralization and total soil nitrogen data across the CONUS were obtained from three different ecosystems: low elevation forests, high elevation forests, and grasslands. Equations to predict net nitrogen mineralization were developed through stepwise linear regression using total Kjeldahl nitrogen, air temperature, precipitation, and nitrogen deposition as predictor variables for four categories: low elevation high temperature forests (coefficient of determination, R2 = 0.83), low elevation low temperature forests (R2 = 0.74), high elevation forests (R2 = 0.80), and grasslands (R2 = 0.88). A map of net nitrogen mineralization was developed in GIS using these equations and national-scale databases for the CONUS. The result shows that net nitrogen mineralization varies widely across the US. Grasslands were predicted to have the lowest net nitrogen mineralization, while low elevation forests in the east had the highest. Mean values were 14.3 kg·ha-1·yr-1 for grasslands, 22.6 kg·ha-1·yr-1 for high elevation forests, 58 kg·ha-1·yr-1 for low elevation low temperature forests, and 82.9 kg·ha-1·yr-1 for low elevation high temperature forests. This continental scale estimation of net nitrogen mineralization provides a means of comparing net nitrogen mineralization across regions, and the databases developed from this study are useful for accounting for nitrogen limitations in large scale ecosystem modeling.
基金supported by the National Natural Science Foundation of China(32070530)the National Key Research and Development Program of China(2019YFA0607103)+1 种基金the Qilian Mountain National Park Qinghai Province Management Bureauthe National Forestry and Grassland Administration of China。
文摘Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population size and distribution of the Black-necked Crane(Grus nigricollis)in the Yarlung Zangbo River Basin(YZRB)from 10 to 29 January 2022,and predicted the current potentially suitable habitat distribution and its effective factors using the Max Ent model.A total of 9337 wintering Black-necked Cranes were recorded in the YZRB in 2022,76.58%of which were primarily found in Lhunzub,Samzhubze,Namling,and Lhaze.Compared to 2018,the crane population has exhibited a notable decline in Samzhubze and Taktse,likely due to farmland plowing,winter irrigation,changes in agricultural practices,road construction and hydraulic projects.The crane population within various counties exhibited a significant positive correlation with the suitable habitat area(r=0.70,P=0.002,n=17).We also found that the currently suitable habitat area covered 17,204 km~2,of which only 3244 km~2(18.86%)was effectively protected at the national level,which was predominantly distributed in farmland and rangeland habitats characterized by gentle slopes,altitudes not exceeding 4500 m,and proximity to human settlements along rivers,where suitable isothermal values(51)and less seasonal precipitation(20 mm)prevail.Our study will be helpful for formulating reasonable conservation strategies to protect the core population of this threatened highland flagship species.
文摘Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this problem,the traditional particle tracking velocimetry method based on an optical flow was improved.The level set segmentation algorithm was used to obtain the boundary contour of the region with large velocity gradient changes,and the non-uniform flow field was divided into regions according to the boundary contour to obtain sub-regions with uniform velocity distribution.The particle tracking velocimetry method based on optical flow was used to measure the granular flow velocity in each sub-region,thus avoiding the problem of granular flow distribution.The simulation results show that the measurement accuracy of this method is approximately 10%higher than that of traditional methods.The method was applied to a velocity measurement experiment on dense granular flow in silos,and the velocity distribution of the granular flow was obtained,verifying the practicality of the method in granular flow fields.
基金supported by the National Natural Science Foundation of China(No.22273103)the National Natural Science Foundation of China(NSFC Center for Chemical Dynamics)(No.22288201)+1 种基金Dalian Institute of Chemical Physics(DICP I202230)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(grant GJJSTD20220001)。
文摘Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were generat-ed with internal excitation by multiphoton photolysis of CHBr_(3)at 248 nm,and its rotational temperature was found to relax to the flow temperature in a few microseconds by colliding with bath gas.The relaxation rate coefficients for CH(X^(2)Π,v=0)radical in He,Ar,and N_(2)flow were obtained by time-resolved laser-induced fluorescence measurements,ranging from 10^(-12)cm^(3)·molecule^(-1)·s^(-1)to 10^(-11)cm^(3)·molecule^(-1)·s^(-1).The N_(2)flow exhibits the highest relax-ation rate for CH(X^(2)Π)radical due to its additional rovibrational levels,which allow for more efficient energy dissipation during collisions compared to monoatomic gases.The Ar flow shows a larger relaxation rate than He flow due to its greater polarizability and stronger long-range interaction with the CH(X^(2)Π)radical.
基金supported by grants from the National Major Science and Technology Special Projects for Infectious Diseases of China (2012ZX10004503-008, 2012ZX10001006-002, and 2012ZX10002006-002)National Natural Science Foundation of China (31300748)
文摘Hepatitis B virus(HBV) infection is one of the most serious and prevalent viral diseases in the world. Although several anti-HBV drugs have been used clinically, their side and adverse effects limit treatment efficacy. Therefore, it is necessary to identify novel potential anti-HBV agents. The flavonol quercetin has shown activity against some retroviruses, but its effect on HBV remains unclear. In the present study, quercetin was incubated with Hep G2.2.15 cells, as well as Hu H-7 cells transfected with an HBV plasmid. Quercetin was shown to significantly reduce Hepatitis B surface antigen(HBs Ag) and Hepatitis B e antigen(HBe Ag), secretion and HBV genomic DNA levels in both cell lines. In addition, co-incubation with lamivudine(3TC), entecavir(ETV), or adefovir(Ade) further enhanced the quercetin-induced inhibition of HBV replication. This inhibition was partially associated with decreased heat shock proteins and HBV transcription levels. The results indicate that quercetin inhibited HBV antigen secretion and genome replication in human hepatoma cell lines, which suggests that quercetin may be a potentially effective anti-HBV agent.
基金partially supported by the Fundamental Research Funds for the Central Universities(DL12CA12,2572017PZ05)in part by the Research Foundation for Junior Teachers from the Ministry of Education of China(20110062120010)。
文摘Several indices and simple empirical models and ratios of single band from pre-and post-fire Landsat images have been developed to estimate and/or map burn severity.However,these models and indices are usually site-,time-and vegetation-dependent and their applications are limited.The Daxing'an Mountains range has the largest forested area in China and is prone to wildfires.Whether or not the existing models can effectively characterize the burn severity over a large region is unclear.In this study,we used the orthogonal signal correction method based on partial least squares regression(PLSR)to select those variables that better interpret the variance of burn severity.A new index and other commonly used indices were used to construct a new,multivariate PLSR model which was compared with the popular single variable models,according to three assessment indices:relative root mean square error(RMSE%),relative bias(R E%)and Nash–Sutcliffe efficiency(NSE%).The results indicate that the multivariate PLSR model performed better than the other single variable models with higher NSE%(68.2%vs.67.8%)and less RE%(3.7%vs.-8.7%),while achieving almost the same R MSE%.We also discuss the spectral characteristics of the four selected variables for constructing the multivariate PLSR model and their correlation with the field burn severity data.The new model developed from this study should help to better understand the patterns of forest burn severity and assist in vegetation restoration efforts in the region.
文摘A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.
基金the Project of the MOST,China(No.2015FY310100)Project of China Geology Survey(No.DD20160120-04) for their financial supportsthe Key Lab of Evolution of Past Life in NE Asia, MLRC (in Shenyang), for research support
文摘The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and related radiometric dating.A new species of angiospermous fossil plant.Platanus heilongjiangensis sp.nov.,from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2±1.7 Ma.indicating that the Upper Houshigou Formation is of Cenomanian age.This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation,but also shows that Platanus flourished in the early Late Cretaceous floras of the region.This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.
基金the Foundation for Beijing Science and Technology Development of TCM,No.JJ2016-10the National Traditional Chinese Medicine Innovative Talents Training Project from Beijing Municipal Science and Technology Commission,No.Z171100001717006.
文摘BACKGROUND Glioblastoma is the most common type of brain tumor and is invariably fatal,with a mean survival time of 8-15 mo for recently diagnosed tumors,and a 5-year survival rate of only 7.2%.The standard treatment for newly diagnosed glioblastoma includes surgery followed by concurrent chemoradiotherapy and further adjuvant temozolomide.However,the prognosis remains poor and longterm survival is rare.This report aimed to demonstrate a new therapeutic strategy for the treatment of glioblastoma.CASE SUMMARY A patient was referred to the Department of Neurosurgery with an intracranial space-occupying lesion with a maximum diameter of approximately 5 cm.The tumor was compressing functional areas,and the patient accordingly underwent partial resection and concurrent chemoradiotherapy.The imaging and pathological findings were consistent with a diagnosis of glioblastoma with oligodendroglioma differentiation(World Health Organization IV).The patient was finally diagnosed with glioblastoma.However,the patient discontinued treatment due to intolerable side effects,and was prescribed Kangliu pill(KLP)7.5 g three times/d,which he has continued to date.Significant shrinkage of the tumor(maximum diameter reduced from about 3.5 to about 2 cm)was found after 3 mo of KLP therapy,and the tumor was further reduced to about 1 cm after 3 years.The patient’s symptoms of headache,limb weakness,and left hemiplegia were relieved,with no side effects.CONCLUSION KLP has been a successful intervention for glioblastoma, and the current caseindicates that traditional Chinese medicine may offer effective alternativetherapies for glioblastoma.
基金Supported by PP RAS Projects 06-1-P11-022 , 06-1-P18-081 , Russia and NSFC-RFBR Proj .30511120003 , Key Lab Modern Paleont . Stratig.(NIGPAS) Proj .903109 , China
文摘An early Norian flora from the Partizansk River Basin of Primorye, Far-East of Russia, is described in detail for the first time, in which over 25 taxa are reported. The flora is dominated by cycadoalean, bennettitalean and coniferous plants, associated with a lot of ferns and czekanowskialean plants, and with a few ginkgoalean. In floristic characteristics, the flora can be well comparable with Late Triassic Mongugai flora of southwestern Primorye and its neighboring Tianqiaoling flora of eastern Jilin, China, as well with the Yamanoi and Nariwa floras from southwestern Japan. As the plant-bearing strata are sandwiched in the lower Norian marine beds yielding marine fauna, the age of the Partizansk flora is well evidenced as the early Norian. Paleophytogeographically, the flora appears to be in the ecotone of the Medio-Triassic and Arcto-Triassic floristic regions in Eurasia, and indicates probably warm temperate or subtropic vegetation in nature. Four new species are reported in this paper, including Ctenis elegantus sp. nov, Ixostrobus pacificus sp. nov., Elatocladus elegantus sp. nov. and E. prynadae sp. nov.
基金supported by the US National Science Foundation(No.CHE-1566636)
文摘The ultraviolet （UV） photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236-254 nm using the high-n Rydberg-atom time-of-flight （HRTOF） technique. The H-atom photofragment yield spectrum of the 1-pentyl radical shows a broad UV absorption feature peaking near 245 nm, similar to the 2pz→3s absorption bands of ethyl and n-propyl. The center-of-mass translational energy distribution, P（ET）, of the H＋CsH10 product channel is bimodal, with a slow peak at -5 kcal/mol and a fast peak at -50 kcal/mol. The fraction of the average translational energy release in the total available energy, （fT）, is 0.30, with those of the slow and fast components being 0.13 and 0.58, respectively. The slow component has an isotropic product angular distribution, while the fast component is anisotropic with an anisotropy parameter -0.4. The bimodal translational energy and angular distributions of the H＋C5H10 products indicate two H-atom elimination channels in the photodissociation of 1-pentyl： （i） a direct, prompt dissociation from the electronic excited state and/or the repulsive part of the ground electronic state potential energy surface; and （ii） a unimolecular dissociation of internally hot radical in the ground electronic state after internal conversion from the electronic excited state.
基金supported by the US National Science Foundation (grant number CHE-1566636)UC MEXUS-CONACYT Collaborative Grant (CN-1668)DGAPA-UNAM for support through Project PAPIIT IN-115916.
文摘Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.
文摘Sleep is essential to the normal psychological and physiological activities of the human body.Increasing evidence indicates that sleep deprivation is associated with the occurrence,development,and poor treatment effects of various arrhythmias.Sleep deprivation affects not only the peripheral nervous system but also the central nervous system,which regulates the occurrence of arrhythmias.In addition,sleep deprivation is associated with apoptotic pathways,mitochondrial energy metabolism disorders,and immune system dysfunction.Although studies increasingly suggest that pathological sleep patterns are associated with various atrial and ventricular arrhythmias,further research is needed to identify specific mechanisms and recommend therapeutic interventions.This review summarizes the findings of sleep deprivation in animal experiments and clinical studies,current challenges,and future research directions in the field of arrhythmias.
文摘The impacts of hurricane disturbance and climate variability on carbon dynamics in a coastal forested wetland in South Carolina of USA were simulated using the Forest-DNDC model with a spatially explicit approach. The model was validated using the measured biomass before and after Hurricane Hugo and the biomass inventories in 2006 and 2007, showed that the Forest- DNDC model was applicable for estimating carbon dynamics with hurricane disturbance. The simulated results indicated that Hurricane Hugo in 1989 substantially influenced carbon storage immediately after the disturbance event. The simulated net ecosystem exchange (NEE) for the 58-year period (1950-2007) indicated that the hurricane reduced CO2 sequestration due primarily to the increased decomposition of a large amount of litter and woody debris, including fallen trees (over 80% of pre-hurricane trees), debris and branches, and dead roots. The inter-annual fluctuation of soil CO2 flux showed that the climate variability interfered substantially soil carbon dynamics in the forest. The results showed that there were substantial spatial and temporal differences in CO2 flux (3.2 - 4.8 Mg·C·ha–1) and wood biomass due to the differences in physical and biogeochemical characteristics in the forest.
