Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells a...Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.展开更多
The coastal upwelling has profound influence on the surrounding ecosystem by supplying the nutrient-replete water to the euphotic zone.Nutrient biogeochemistry was investigated in coastal waters of the eastern Hainan ...The coastal upwelling has profound influence on the surrounding ecosystem by supplying the nutrient-replete water to the euphotic zone.Nutrient biogeochemistry was investigated in coastal waters of the eastern Hainan Island in summer 2015 and autumn 2016.From perspectives of nutrient dynamics and physical transport,the nutrient fluxes entered the upper 50 m water depth(between the mixed layer and the euphotic zone)arisen from the upwelling were estimated to be 2.5-5.4 mmol/(m^(2)·d),0.15-0.28 mmol/(m^(2)·d),and 2.2-7.2 mmol/(m^(2)·d)for dissolved inorganic nitrogen(DIN),phosphate(DIP),and dissolved silicate(DSi),respectively,which were around 6-to 12-fold those in the background area.The upwelled nutrients supported an additional plankton growth of(14.70±8.95)mg/m^(2)for chlorophyll a(Chl a).The distributions of nitrateδ^(15)N andδ^(18)O above the 300 m water depth(top of the North Pacific Intermediate Water)were different among the upwelling area,background area in summer,and the stations in autumn,and the difference of environmental and biogeochemical conditions between seasons should be the reason.The higher DIN/DIP concentration ratio,nitrate concentration anomaly,and lower nitrate isotope anomaly(Δ(15,18))in the upper ocean in summer than in autumn indicated the stronger nitrogen fixation and atmospheric deposition,and the following fixed nitrogen regeneration in summer.The higher values of Chl a and nitrateδ^(15)N andδ^(18)O within the euphotic zone in autumn than the background area in summer suggested the stronger nitrate assimilation in autumn.The differences in relatively strength of the assimilation,nitrogen fixation and atmospheric deposition,and the following remineralization and nitrification between the two seasons made the higherδ^(18)O:δ^(15)N and larger difference of enzymatic isotope fractionation factors^(15)εand^(18)εfor nitrate assimilation in summer than in autumn above the North Pacific Tropical Water.展开更多
Quantifying the gross and net production is an essential component of carbon cycling and marine ecosystem studies.Triple oxygen isotope measurements and the O_(2)/Ar ratio are powerful indices in quantifying the gross...Quantifying the gross and net production is an essential component of carbon cycling and marine ecosystem studies.Triple oxygen isotope measurements and the O_(2)/Ar ratio are powerful indices in quantifying the gross primary production and net community production of the mixed layer zone,respectively.Although there is a substantial advantage in refining the gas exchange term and water column vertical mixing calibration,application of mixed layer depth history to the gas exchange term and its contribution to reducing indices error are unclear.Therefore,two cruises were conducted in the slope regions of the northern South China Sea in October 2014(autumn)and June 2015(spring).Discrete water samples at Station L07 in the upper 150 m depth were collected for the determination ofδ^(17)0,δ^(18)O,and the O_(2)/Ar ratio of dissolved gases.Gross oxygen production(GOP)was estimated using the triple oxygen isotopes of the dissolved O_(2),and net oxygen production(NOP)was calculated using O_(2)/Ar ratio and O_(2)concentration.The vertical mixing effect in NOP was calibrated via a N_(2)O based approach.GOP for autumn and spring was(169±23)mmol/(m^(2)·d)(by O_(2))and(189±26)mmol/(m^(2)·d)(by O_(2)),respectively.While NOP was 1.5 mmol/(m^(2)·d)(by O_(2))in autumn and 8.2 mmol/(m^(2)·d)(by O_(2))in spring.Application of mixed layer depth history in the gas flux parametrization reduced up to 9.5%error in the GOP and NOP estimations.A comparison with an independent O_(2)budget calculation in the diel observation indicated a26%overestimation in the current GOP,likely due to the vertical mixing effect.Both GOP and NOP in June were higher than those in October.Potential explanations for this include the occurrence of an eddy process in June,which may have exerted a submesoscale upwelling at the sampling station,and also the markedly higher terrestrial impact in June.展开更多
To understand the temporal and spatial variations in nutrient dynamics,as well as the potential cross-shelf transport of nutrients between the East China Sea(ECS)shelf and the northwestern Pacific Ocean,six field obse...To understand the temporal and spatial variations in nutrient dynamics,as well as the potential cross-shelf transport of nutrients between the East China Sea(ECS)shelf and the northwestern Pacific Ocean,six field observations covering the ECS were conducted in spring,summer,and autumn in 2011 and 2013.Nutrient dynamics in the ECS and nutrient exchange between shelf water and the open ocean were examined.High concentrations of dissolved inorganic nutrients were detected in the nearshore surface layer and offshore bottom layer in different seasons,and the concentrations of dissolved inorganic nutrients in surface seawater were lower in summer and autumn than in spring.The concentrations of dissolved organic nutrients in Kuroshio surface water were slightly lower in summer than in spring,but the concentrations in Kuroshio subsurface water were slightly higher in summer than in spring.There were abundant nutrient reservoirs in the euphotic zone of the ECS,which explained the high primary productivity.The evaluation of cross-shelf transport indicated that nutrients from shelf water were transported out across the 200 m isobath through the surface layer with the density(σ)less than 23.0 kg/m^(3) in spring.The flux of dissolved inorganic nitrogen transported from the ECS shelf to the Northwest Pacific Ocean in spring was equivalent to 21%of the atmospheric nitrogen deposition in the Northwest Pacific Ocean.In summer,the onshore flux in the surface and bottom layers accounted for 80%of the total flux,and the transportation of nutrients along the surface layer to the continental shelf contributed to the nutrient storage and primary productivity of the euphotic zone in the ECS shelf in summer.展开更多
Curved composite bridges and curved steel bridges have already been constructed around the world;however, the calculation for shear buckling of curved bridge webs generally uses the equations for straight bridge webs ...Curved composite bridges and curved steel bridges have already been constructed around the world;however, the calculation for shear buckling of curved bridge webs generally uses the equations for straight bridge webs or just introduces a modification factor for bridge design. In this paper, the curved bridge web is equivalent to an isotropic cylindrical flat shell, and the double triangular series satisfying four-edge simply supported boundaries are used as the displacement function of the shell. Then by means of the Galerkin method, the analytical formula for elastic shear buckling stress of curved bridge webs is deduced. The parameter studies show that the shear buckling coefficient kc of curved bridge webs is positively correlated with the parameter h2 / (Rt), and negatively correlated with the length-height ratio l/ h. This implies that the elastic shear buckling stress of a curved bridge web is larger than that of an equivalent straight bridge web. For a curved bridge with the parameter h2 / (Rt) less than 2, the amount of increase is less than 4.5%. The elastic shear buckling stress of curved bridge webs can be estimated conservatively as the webs in straight bridges. While for a curved bridge with larger h2 / (Rt), using the equations for straight girders to calculate the elastic shear buckling stress is too conservative. The proposed formulas provide a more accurate estimation for shear buckling stress of curved bridge webs.展开更多
Background:Glecirasib,an inhibitor of Kirsten rat sarcoma viral oncogene homolog glycine-to-cysteine substitution at codon 12(KRAS G12C),has exhibited clinical activity in non-small-cell lung cancer(NSCLC)and colorect...Background:Glecirasib,an inhibitor of Kirsten rat sarcoma viral oncogene homolog glycine-to-cysteine substitution at codon 12(KRAS G12C),has exhibited clinical activity in non-small-cell lung cancer(NSCLC)and colorectal cancer(CRC).Here,we investigated the efficacy and safety of glecirasib in patients with pancreatic ductal adenocarcinoma(PDAC)and other solid tumors(excluding NSCLC and CRC)that rarely harbor the KRAS G12C mutation but for which effective treatment options remain limited.Methods:We conducted and analyzed two open-label,phase I/II trials in adult patients with KRAS G12C mutant solid tumors,in which glecirasib was administered orally.The two trials had similar eligibility criteria and endpoints but differed in the regions of patient recruitment.We performed a pooled analysis of all patients,excluding NSCLC and CRC,from both trials.The primary end-point in the pooled population was objective response rate(ORR).Efficacy and safety were assessed in patients who received at least one dose of glecirasib.Results:As of June 30,2024,the pooled analysis included 54 patients who were treated with glecirasib:32 PDACs,8 biliary tract cancers(BTCs),4 small intestinal cancers,3 gastric cancers,2 appendiceal cancers,and 5 other tumors.At baseline,24 received≥two prior lines of systemic therapy.Of the 53 efficacyevaluable patients,the confirmed ORR was 50.9%(95%confidence interval[CI],36.8%-64.9%),with an ORR of 46.9%(95%CI,29.1%-65.3%)in PDAC patients.Among other solid tumors,ORR was 71.4%(5/7)in BTC,100%(4/4)in small intestinal cancer,and 66.7%(2/3)in gastric cancer.Median progression-free survival and median overall survival were 6.9 and 10.8 months,respectively,in the overall population,and 5.5 and 10.8 months,respectively,in patients with PDAC.Treatment-related adverse events(TRAEs)of any grade occurred in 94.4%patients,with grade≥3 TRAEs in 27.8%.No fatal TRAEs or TRAEs leading to treatment discontinuation occurred.Conclusions:Glecirasib showed promising efficacy and was well tolerated in patients with PDAC and other advanced solid tumors(beyond NSCLC and CRC),warranting further expedited clinical development in this patient population.Trial registration:ClinicalTrials.gov identifier:NCT05009329 and NCT05002270.展开更多
During the COVID-19 pandemic,hospital wards served as crucial medical infrastructure for patient treatment.The existing ventilation systems in hospital wards are often criticized for their high energy consumption and ...During the COVID-19 pandemic,hospital wards served as crucial medical infrastructure for patient treatment.The existing ventilation systems in hospital wards are often criticized for their high energy consumption and poor pollutant removal.This study introduces an improved active chilled beam(ACB)system for wards.This system integrates an ionization module with the ACB,utilizing the ACB’s supply air jet and exhaust air convergence to create a directed airflow within the ward,effectively purifying aerosols.First,a validated CFD model is employed to simulate airflow generated by the ACB and the movement of aerosols exhaled by patients.Particle image velocimetry(PIV)is then used to visualize the indoor directed airflow created by the ACB.The targeted aerosol removal performance of the ACB system is quantitatively described using the TARGETING index.To address the cumbersome calculation of the TARGETING index,a qualitative rapid identification method for targeted ventilation is proposed.Finally,the purification effect of the ACB system in multipatient wards was optimized through theoretical analysis.Compared with existing systems,the improved ACB system enhances the targeted aerosol removal performance by 41.9%–62.5%,and achieves energy savings of 33.3%.In multipatient wards,the ACB system can reduce the cross-infection risk by 80.5%–91.0%.展开更多
Elevators,as an enclosed and often crowded space,pose a high risk of airborne infections due to ineffective ventilation.To mitigate this issue,this study introduces a reinforced exhaust at low velocity(RELV)system,spe...Elevators,as an enclosed and often crowded space,pose a high risk of airborne infections due to ineffective ventilation.To mitigate this issue,this study introduces a reinforced exhaust at low velocity(RELV)system,specifically designed to enhance aerosol removal efficiency in elevators.The performance of the RELV system was assessed through computational fluid dynamics(CFD)simulations,employing the Renormalization Group(RNG)k–εturbulence model to simulate airflow and the Lagrangian method to track particle motion.The RELV system was benchmarked against three conventional ventilation strategies:mixed ventilation(MV),displacement ventilation(DV),and local exhaust(Exhaust).Results demonstrated that the RELV system,optimized at a momentum ratio of 0.2,achieved a remarkable 72.9% aerosol removal efficiency within 120 s,significantly outperforming the 16.1%removal efficiency of the MV system under Scenario I,where the patient was located at the elevator’s center.Furthermore,the viral aerosol concentration in the breathing zone was reduced from 2.03×10^(-2) mg/cm^(3) in the MV system to 1.02×10^(-3) mg/cm^(3) in the RELV system.The RELV system features simple design and compatibility with existing ventilation systems,offering an effective solution to improve air quality in elevators and other enclosed environments.Additionally,this study provides a velocity decay curve for low-velocity jets in the RELV system.This curve offers valuable insights for designing ventilation systems in similar settings.展开更多
Erratum to BUILD SIMUL,DOI 10.1007/s12273-025-1258-2.The name of the last author Runmin Zhao was incorrectly listed as Runming Zhao in the original online version of the article.The article has been updated with the c...Erratum to BUILD SIMUL,DOI 10.1007/s12273-025-1258-2.The name of the last author Runmin Zhao was incorrectly listed as Runming Zhao in the original online version of the article.The article has been updated with the correct name.展开更多
A hydrogen peroxide[H_(2)O_(2)]detection system is demonstrated with multi-pass tunable diode laser absorption spectroscopy using a 75 m Herriott absorption cell.The system utilizes an~8μm continuous wave distributed...A hydrogen peroxide[H_(2)O_(2)]detection system is demonstrated with multi-pass tunable diode laser absorption spectroscopy using a 75 m Herriott absorption cell.The system utilizes an~8μm continuous wave distributed feedback quantum cascade laser[CW DFB-QCL]targeting a prominent H_(2)O_(2)line at 1253.1 cm^(-1)within the fundamental absorption band.A wavelength modulation spectroscopy with the first harmonic normalized second harmonic[WMS-2f/1f]detection method is employed to eliminate laser light intensity fluctuations.Calibration of the system is conducted by means of chemical titration to establish the correlation between the peak value of the 2f/1f signal and H_(2)O_(2)concentration.An Allan-Werle deviation analysis shows that a minimum detection limit[MDL]of 2.9 ppb[1 ppb=10^(-9)]for H_(2)O_(2)is achieved with an average time of 147 s.To the best of our knowledge,this is the lowest detection limit for H_(2)O_(2)at the wavenumber of 1253.1 cm^(-1).The system exhibits robust resistance to interference from other gases,especially water vapor[H_(2)O],making it suitable for measuring the residual concentration of H_(2)O_(2)post-sterilization and the concentration of H_(2)O_(2)in the atmosphere.展开更多
Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin...Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin expression is reactivated and Nestinpositive(Nestin;) cells aggregate at the injury site. However, the derivation of Nestin;cells is not clearly defined. Here, we found that Nestin expression was substantially increased in the lesion edge and lesion core after SCI. Using a tamoxifen inducible CreER(T2)-loxP system, we verified that ependymal cells contribute few Nestin;cells either to the lesion core or the lesion edge after SCI. In the lesion edge, GFAP+astrocytes were the main cell type that expressed Nestin;they then formed an astrocyte scar.In the lesion core, Nestin;cells expressed αSMA or Desmin, indicating that they might be derived from pericytes. Our results reveal that Nestin;cells in the lesion core and edge came from various cell types and rarely from ependymal cells after complete transected SCI, which may provide new insights into SCI repair.展开更多
Anthropogenic activity is an important driver of changes in the chemistry of nutrients(N,P,and Si)over watersheds at the sub-continental scale(e.g.,106km^(2))and can markedly modify their seaward fluxes to the global ...Anthropogenic activity is an important driver of changes in the chemistry of nutrients(N,P,and Si)over watersheds at the sub-continental scale(e.g.,106km^(2))and can markedly modify their seaward fluxes to the global ocean.In the present study,we reviewed the current status of nutrient chemistry in Changjiang(Yangtze River)based on data collected through 11 expeditions along a river course spanning 4,500 km and 15–20 major tributaries during 1997–2016 as well as monthly monitoring at the river mouth since 1980.The data were analyzed together with published results in the literature to synthesize the recent developments and current state of nutrients in the Changjiang.Previously published results from the Qinghai-Tibetan Plateau head waters were included to realize the systematics of nutrients for the whole drainage basin.Here,we showed that tributaries of the upper reaches of watersheds collectively determine the regime with high concentration and skewed species ratio of nutrients in the Changjiang mainstream,producing profound effects over a water course of 2,000–2,500 km further downstream and until the river mouth.Moreover,using data across the Three Gorges Reservoir(TGR)during 2003–2016,we evaluated the trapping and/or amplifying effects of the Three Gorges Dam(TGD)on nutrient chemistry.Tide-influenced river delta contributed an additional 20%dissolved inorganic phosphorus and 5–10%dissolved inorganic nitrogen and dissolved silicates to the seaward flux,dramatically affecting the stoichiometry of nutrients at the river mouth.Next,based on compiled data on supply and export,legacy nutrients were evaluated.Both nitrogen and phosphorus are in the accumulation phase over the watersheds,and the legacy nutrient fluxes are much higher than the annual riverine seaward fluxes.Finally,we demonstrated that the seaward fluxes of anthropogenic nutrients from the Changjiang exceed those from other top 10 largest rivers on this planet,which can be attributed to land use changes in the China over the last three to four decades.展开更多
The plasticity of stem cells in response to environmental change is critical for multicellular organisms.Here,we show that MYB3R-like directly activates the key plant stem-cell regulator WUSCHEL(WUS)by recruiting the ...The plasticity of stem cells in response to environmental change is critical for multicellular organisms.Here,we show that MYB3R-like directly activates the key plant stem-cell regulator WUSCHEL(WUS)by recruiting the methyltransferase ROOT INITIATION DEFECTIVE 2(RID2),which functions in m7G methylation of the 5′cap of WUS mRNA to protect it from degradation.Transcriptomic and molecular analyses showed that protein-folding genes are repressed by WUS to maintain precise protein synthesis in stem cells by preventing the reuse of misfolded proteins.Interestingly,we found that upon heat stress,the MYB3R-like/RID2 module is repressed to reduce WUS transcript abundance through decapping of nascent WUS mRNA.This releases the inhibition of protein-folding capacity in stem cells and protects them from heat shock by eliminating misfolded protein aggregation.Taken together,our results reveal a strategic trade-off whereby plants reduce the accuracy of protein synthesis in exchange for the survival of stem cells at high temperatures.展开更多
This paper introduces a novel material,low-carbon high-strength recycled aggregate concrete(LCHRAC),developed by activating ground granulated blast-furnace slag(GGBS)and silica fume(SF)in an alkaline environment and i...This paper introduces a novel material,low-carbon high-strength recycled aggregate concrete(LCHRAC),developed by activating ground granulated blast-furnace slag(GGBS)and silica fume(SF)in an alkaline environment and integrating recycled aggregate.To evaluate its mechanical properties,uniaxial compressive tests were performed,systematically analyzing the effects of recycled concrete aggregate(RCA)substitution ratios,as well as the characteristic parameters of steel and polypropylene(PP)fibers,on LCHRAC’s mechanical behavior.The results indicated that compressive strength shows a gradual decline as the RCA substitution ratio increases,with a moderate reduction of 7.1%up to 50%replacement,and a more significant drop,retaining only 68.6%at 100%replacement.In contrast,the peak strain increases linearly,showing a 29%improvement at full replacement,while the toughness index exhibits a consistent upward trend,increasing by approximately 123%at a 100%replacement rate.Based on experimental data,empirical models were developed to predict the influence of key control variables on the compressive strength,peak strain,elastic modulus,and the uniaxial compressive stress-strain behavior of LCHRAC.Additionally,advanced characterization techniques,including X-ray diffraction(XRD),thermogravimetric analysis(TGA/DTG),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS),were employed to elucidate the hydration mechanisms of the slag-silica fume composite system.These findings provide a comprehensive understanding of the mechanical performance and microstructural characteristics of LCHRAC,contributing to its potential application in sustainable construction practices.展开更多
基金supported by the Stem Cell and Translation National Key Project,No.2016YFA0101403(to ZC)the National Natural Science Foundation of China,Nos.82171250 and 81973351(to ZC)+6 种基金the Natural Science Foundation of Beijing,No.5142005(to ZC)Beijing Talents Foundation,No.2017000021223TD03(to ZC)Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan,No.CIT&TCD20180333(to ZC)Beijing Municipal Health Commission Fund,No.PXM2020_026283_000005(to ZC)Beijing One Hundred,Thousand,and Ten Thousand Talents Fund,No.2018A03(to ZC)the Royal Society-Newton Advanced Fellowship,No.NA150482(to ZC)the National Natural Science Foundation of China for Young Scientists,No.31900740(to SL)。
文摘Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.
基金The National Natural Science Foundation of China under contract No.41376086the Taishan Scholars Programme of Shandong Provincethe Aoshan Talents Program supported by the Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2015ASTP-OS08。
文摘The coastal upwelling has profound influence on the surrounding ecosystem by supplying the nutrient-replete water to the euphotic zone.Nutrient biogeochemistry was investigated in coastal waters of the eastern Hainan Island in summer 2015 and autumn 2016.From perspectives of nutrient dynamics and physical transport,the nutrient fluxes entered the upper 50 m water depth(between the mixed layer and the euphotic zone)arisen from the upwelling were estimated to be 2.5-5.4 mmol/(m^(2)·d),0.15-0.28 mmol/(m^(2)·d),and 2.2-7.2 mmol/(m^(2)·d)for dissolved inorganic nitrogen(DIN),phosphate(DIP),and dissolved silicate(DSi),respectively,which were around 6-to 12-fold those in the background area.The upwelled nutrients supported an additional plankton growth of(14.70±8.95)mg/m^(2)for chlorophyll a(Chl a).The distributions of nitrateδ^(15)N andδ^(18)O above the 300 m water depth(top of the North Pacific Intermediate Water)were different among the upwelling area,background area in summer,and the stations in autumn,and the difference of environmental and biogeochemical conditions between seasons should be the reason.The higher DIN/DIP concentration ratio,nitrate concentration anomaly,and lower nitrate isotope anomaly(Δ(15,18))in the upper ocean in summer than in autumn indicated the stronger nitrogen fixation and atmospheric deposition,and the following fixed nitrogen regeneration in summer.The higher values of Chl a and nitrateδ^(15)N andδ^(18)O within the euphotic zone in autumn than the background area in summer suggested the stronger nitrate assimilation in autumn.The differences in relatively strength of the assimilation,nitrogen fixation and atmospheric deposition,and the following remineralization and nitrification between the two seasons made the higherδ^(18)O:δ^(15)N and larger difference of enzymatic isotope fractionation factors^(15)εand^(18)εfor nitrate assimilation in summer than in autumn above the North Pacific Tropical Water.
基金The National Key Research and Development Programs of China of the Ministry of Science and Technology under contract Nos 2020YFA0608301,2014CB441503the National Natural Science Foundation of China under contract Nos 41976042,41776122+1 种基金the Fundamental Research Funds for the Central Universitiesthe Taishan Scholars Program of Shandong Province,China。
文摘Quantifying the gross and net production is an essential component of carbon cycling and marine ecosystem studies.Triple oxygen isotope measurements and the O_(2)/Ar ratio are powerful indices in quantifying the gross primary production and net community production of the mixed layer zone,respectively.Although there is a substantial advantage in refining the gas exchange term and water column vertical mixing calibration,application of mixed layer depth history to the gas exchange term and its contribution to reducing indices error are unclear.Therefore,two cruises were conducted in the slope regions of the northern South China Sea in October 2014(autumn)and June 2015(spring).Discrete water samples at Station L07 in the upper 150 m depth were collected for the determination ofδ^(17)0,δ^(18)O,and the O_(2)/Ar ratio of dissolved gases.Gross oxygen production(GOP)was estimated using the triple oxygen isotopes of the dissolved O_(2),and net oxygen production(NOP)was calculated using O_(2)/Ar ratio and O_(2)concentration.The vertical mixing effect in NOP was calibrated via a N_(2)O based approach.GOP for autumn and spring was(169±23)mmol/(m^(2)·d)(by O_(2))and(189±26)mmol/(m^(2)·d)(by O_(2)),respectively.While NOP was 1.5 mmol/(m^(2)·d)(by O_(2))in autumn and 8.2 mmol/(m^(2)·d)(by O_(2))in spring.Application of mixed layer depth history in the gas flux parametrization reduced up to 9.5%error in the GOP and NOP estimations.A comparison with an independent O_(2)budget calculation in the diel observation indicated a26%overestimation in the current GOP,likely due to the vertical mixing effect.Both GOP and NOP in June were higher than those in October.Potential explanations for this include the occurrence of an eddy process in June,which may have exerted a submesoscale upwelling at the sampling station,and also the markedly higher terrestrial impact in June.
基金The National Science Foundation of China under contract No.42176040the National(Basic)Research and Development Program of China supported by Ministry of Science and Technology under contract Nos.2016YFA0600902 and 2011CB409802/03+1 种基金the Taishan Scholars Program of Shandong Provincethe Aoshan Talents Program supported by the National Laboratory for Marine Science and Technology(Qingdao).
文摘To understand the temporal and spatial variations in nutrient dynamics,as well as the potential cross-shelf transport of nutrients between the East China Sea(ECS)shelf and the northwestern Pacific Ocean,six field observations covering the ECS were conducted in spring,summer,and autumn in 2011 and 2013.Nutrient dynamics in the ECS and nutrient exchange between shelf water and the open ocean were examined.High concentrations of dissolved inorganic nutrients were detected in the nearshore surface layer and offshore bottom layer in different seasons,and the concentrations of dissolved inorganic nutrients in surface seawater were lower in summer and autumn than in spring.The concentrations of dissolved organic nutrients in Kuroshio surface water were slightly lower in summer than in spring,but the concentrations in Kuroshio subsurface water were slightly higher in summer than in spring.There were abundant nutrient reservoirs in the euphotic zone of the ECS,which explained the high primary productivity.The evaluation of cross-shelf transport indicated that nutrients from shelf water were transported out across the 200 m isobath through the surface layer with the density(σ)less than 23.0 kg/m^(3) in spring.The flux of dissolved inorganic nitrogen transported from the ECS shelf to the Northwest Pacific Ocean in spring was equivalent to 21%of the atmospheric nitrogen deposition in the Northwest Pacific Ocean.In summer,the onshore flux in the surface and bottom layers accounted for 80%of the total flux,and the transportation of nutrients along the surface layer to the continental shelf contributed to the nutrient storage and primary productivity of the euphotic zone in the ECS shelf in summer.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51378106)
文摘Curved composite bridges and curved steel bridges have already been constructed around the world;however, the calculation for shear buckling of curved bridge webs generally uses the equations for straight bridge webs or just introduces a modification factor for bridge design. In this paper, the curved bridge web is equivalent to an isotropic cylindrical flat shell, and the double triangular series satisfying four-edge simply supported boundaries are used as the displacement function of the shell. Then by means of the Galerkin method, the analytical formula for elastic shear buckling stress of curved bridge webs is deduced. The parameter studies show that the shear buckling coefficient kc of curved bridge webs is positively correlated with the parameter h2 / (Rt), and negatively correlated with the length-height ratio l/ h. This implies that the elastic shear buckling stress of a curved bridge web is larger than that of an equivalent straight bridge web. For a curved bridge with the parameter h2 / (Rt) less than 2, the amount of increase is less than 4.5%. The elastic shear buckling stress of curved bridge webs can be estimated conservatively as the webs in straight bridges. While for a curved bridge with larger h2 / (Rt), using the equations for straight girders to calculate the elastic shear buckling stress is too conservative. The proposed formulas provide a more accurate estimation for shear buckling stress of curved bridge webs.
文摘Background:Glecirasib,an inhibitor of Kirsten rat sarcoma viral oncogene homolog glycine-to-cysteine substitution at codon 12(KRAS G12C),has exhibited clinical activity in non-small-cell lung cancer(NSCLC)and colorectal cancer(CRC).Here,we investigated the efficacy and safety of glecirasib in patients with pancreatic ductal adenocarcinoma(PDAC)and other solid tumors(excluding NSCLC and CRC)that rarely harbor the KRAS G12C mutation but for which effective treatment options remain limited.Methods:We conducted and analyzed two open-label,phase I/II trials in adult patients with KRAS G12C mutant solid tumors,in which glecirasib was administered orally.The two trials had similar eligibility criteria and endpoints but differed in the regions of patient recruitment.We performed a pooled analysis of all patients,excluding NSCLC and CRC,from both trials.The primary end-point in the pooled population was objective response rate(ORR).Efficacy and safety were assessed in patients who received at least one dose of glecirasib.Results:As of June 30,2024,the pooled analysis included 54 patients who were treated with glecirasib:32 PDACs,8 biliary tract cancers(BTCs),4 small intestinal cancers,3 gastric cancers,2 appendiceal cancers,and 5 other tumors.At baseline,24 received≥two prior lines of systemic therapy.Of the 53 efficacyevaluable patients,the confirmed ORR was 50.9%(95%confidence interval[CI],36.8%-64.9%),with an ORR of 46.9%(95%CI,29.1%-65.3%)in PDAC patients.Among other solid tumors,ORR was 71.4%(5/7)in BTC,100%(4/4)in small intestinal cancer,and 66.7%(2/3)in gastric cancer.Median progression-free survival and median overall survival were 6.9 and 10.8 months,respectively,in the overall population,and 5.5 and 10.8 months,respectively,in patients with PDAC.Treatment-related adverse events(TRAEs)of any grade occurred in 94.4%patients,with grade≥3 TRAEs in 27.8%.No fatal TRAEs or TRAEs leading to treatment discontinuation occurred.Conclusions:Glecirasib showed promising efficacy and was well tolerated in patients with PDAC and other advanced solid tumors(beyond NSCLC and CRC),warranting further expedited clinical development in this patient population.Trial registration:ClinicalTrials.gov identifier:NCT05009329 and NCT05002270.
基金the National Key R&D Program from the Ministry of Science and Technology,China,on“Comprehensive control of air,soil and groundwater pollution”through Grant No.2022YFC3702803the National Natural Science Foundation of China(NSFC)through grant No.52108084.
文摘During the COVID-19 pandemic,hospital wards served as crucial medical infrastructure for patient treatment.The existing ventilation systems in hospital wards are often criticized for their high energy consumption and poor pollutant removal.This study introduces an improved active chilled beam(ACB)system for wards.This system integrates an ionization module with the ACB,utilizing the ACB’s supply air jet and exhaust air convergence to create a directed airflow within the ward,effectively purifying aerosols.First,a validated CFD model is employed to simulate airflow generated by the ACB and the movement of aerosols exhaled by patients.Particle image velocimetry(PIV)is then used to visualize the indoor directed airflow created by the ACB.The targeted aerosol removal performance of the ACB system is quantitatively described using the TARGETING index.To address the cumbersome calculation of the TARGETING index,a qualitative rapid identification method for targeted ventilation is proposed.Finally,the purification effect of the ACB system in multipatient wards was optimized through theoretical analysis.Compared with existing systems,the improved ACB system enhances the targeted aerosol removal performance by 41.9%–62.5%,and achieves energy savings of 33.3%.In multipatient wards,the ACB system can reduce the cross-infection risk by 80.5%–91.0%.
基金supported by the National Key R&D Program of the Ministry of Science and Technology,China,on“National Quality Infrastructure(NQI)”(Grant No.2023YFF0613101)the National Natural Science Foundation of China(NSFC)through Grant No.52108084.
文摘Elevators,as an enclosed and often crowded space,pose a high risk of airborne infections due to ineffective ventilation.To mitigate this issue,this study introduces a reinforced exhaust at low velocity(RELV)system,specifically designed to enhance aerosol removal efficiency in elevators.The performance of the RELV system was assessed through computational fluid dynamics(CFD)simulations,employing the Renormalization Group(RNG)k–εturbulence model to simulate airflow and the Lagrangian method to track particle motion.The RELV system was benchmarked against three conventional ventilation strategies:mixed ventilation(MV),displacement ventilation(DV),and local exhaust(Exhaust).Results demonstrated that the RELV system,optimized at a momentum ratio of 0.2,achieved a remarkable 72.9% aerosol removal efficiency within 120 s,significantly outperforming the 16.1%removal efficiency of the MV system under Scenario I,where the patient was located at the elevator’s center.Furthermore,the viral aerosol concentration in the breathing zone was reduced from 2.03×10^(-2) mg/cm^(3) in the MV system to 1.02×10^(-3) mg/cm^(3) in the RELV system.The RELV system features simple design and compatibility with existing ventilation systems,offering an effective solution to improve air quality in elevators and other enclosed environments.Additionally,this study provides a velocity decay curve for low-velocity jets in the RELV system.This curve offers valuable insights for designing ventilation systems in similar settings.
文摘Erratum to BUILD SIMUL,DOI 10.1007/s12273-025-1258-2.The name of the last author Runmin Zhao was incorrectly listed as Runming Zhao in the original online version of the article.The article has been updated with the correct name.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Nos.2022C03065,2022C030842022C03162)+3 种基金the Primary Research and Development Plan of Zhejiang Province(No.2023C03014)the Key Research and Development Program of Zhejiang Province(No.2022C03037)the Science and Technology Program of the State Administration of Market Supervision(No.2023MK049)the Science and Technology Program of Market Supervision Administration of Zhejiang Province(Nos.QN2023419 and QN2023420)。
文摘A hydrogen peroxide[H_(2)O_(2)]detection system is demonstrated with multi-pass tunable diode laser absorption spectroscopy using a 75 m Herriott absorption cell.The system utilizes an~8μm continuous wave distributed feedback quantum cascade laser[CW DFB-QCL]targeting a prominent H_(2)O_(2)line at 1253.1 cm^(-1)within the fundamental absorption band.A wavelength modulation spectroscopy with the first harmonic normalized second harmonic[WMS-2f/1f]detection method is employed to eliminate laser light intensity fluctuations.Calibration of the system is conducted by means of chemical titration to establish the correlation between the peak value of the 2f/1f signal and H_(2)O_(2)concentration.An Allan-Werle deviation analysis shows that a minimum detection limit[MDL]of 2.9 ppb[1 ppb=10^(-9)]for H_(2)O_(2)is achieved with an average time of 147 s.To the best of our knowledge,this is the lowest detection limit for H_(2)O_(2)at the wavenumber of 1253.1 cm^(-1).The system exhibits robust resistance to interference from other gases,especially water vapor[H_(2)O],making it suitable for measuring the residual concentration of H_(2)O_(2)post-sterilization and the concentration of H_(2)O_(2)in the atmosphere.
基金supported by grants from the National Natural Science Foundation of China (81891000)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16040700)+1 种基金the National Key R&D Program of China (2017YFA0104701, 2017YFA0104704 and 2016YFC1101501)the Jiangsu Key R&D Program (BE2018664)
文摘Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin expression is reactivated and Nestinpositive(Nestin;) cells aggregate at the injury site. However, the derivation of Nestin;cells is not clearly defined. Here, we found that Nestin expression was substantially increased in the lesion edge and lesion core after SCI. Using a tamoxifen inducible CreER(T2)-loxP system, we verified that ependymal cells contribute few Nestin;cells either to the lesion core or the lesion edge after SCI. In the lesion edge, GFAP+astrocytes were the main cell type that expressed Nestin;they then formed an astrocyte scar.In the lesion core, Nestin;cells expressed αSMA or Desmin, indicating that they might be derived from pericytes. Our results reveal that Nestin;cells in the lesion core and edge came from various cell types and rarely from ependymal cells after complete transected SCI, which may provide new insights into SCI repair.
基金funded by the National Natural Science Foundation of China through the“Creative Research Team”on“Land-Sea Interactions in Highly Turbid Estuaries and Adjacent Coastal Environments”(Grant Nos.40721004 and 41021064)。
文摘Anthropogenic activity is an important driver of changes in the chemistry of nutrients(N,P,and Si)over watersheds at the sub-continental scale(e.g.,106km^(2))and can markedly modify their seaward fluxes to the global ocean.In the present study,we reviewed the current status of nutrient chemistry in Changjiang(Yangtze River)based on data collected through 11 expeditions along a river course spanning 4,500 km and 15–20 major tributaries during 1997–2016 as well as monthly monitoring at the river mouth since 1980.The data were analyzed together with published results in the literature to synthesize the recent developments and current state of nutrients in the Changjiang.Previously published results from the Qinghai-Tibetan Plateau head waters were included to realize the systematics of nutrients for the whole drainage basin.Here,we showed that tributaries of the upper reaches of watersheds collectively determine the regime with high concentration and skewed species ratio of nutrients in the Changjiang mainstream,producing profound effects over a water course of 2,000–2,500 km further downstream and until the river mouth.Moreover,using data across the Three Gorges Reservoir(TGR)during 2003–2016,we evaluated the trapping and/or amplifying effects of the Three Gorges Dam(TGD)on nutrient chemistry.Tide-influenced river delta contributed an additional 20%dissolved inorganic phosphorus and 5–10%dissolved inorganic nitrogen and dissolved silicates to the seaward flux,dramatically affecting the stoichiometry of nutrients at the river mouth.Next,based on compiled data on supply and export,legacy nutrients were evaluated.Both nitrogen and phosphorus are in the accumulation phase over the watersheds,and the legacy nutrient fluxes are much higher than the annual riverine seaward fluxes.Finally,we demonstrated that the seaward fluxes of anthropogenic nutrients from the Changjiang exceed those from other top 10 largest rivers on this planet,which can be attributed to land use changes in the China over the last three to four decades.
基金National Natural Science Foundation of China(grant nos.32321001 and 32130009 to Z.Z.)University of Science and Technology of China Research Funds of the Double First-Class Initiative(grant no.YD9100002025 to Z.Z.).
文摘The plasticity of stem cells in response to environmental change is critical for multicellular organisms.Here,we show that MYB3R-like directly activates the key plant stem-cell regulator WUSCHEL(WUS)by recruiting the methyltransferase ROOT INITIATION DEFECTIVE 2(RID2),which functions in m7G methylation of the 5′cap of WUS mRNA to protect it from degradation.Transcriptomic and molecular analyses showed that protein-folding genes are repressed by WUS to maintain precise protein synthesis in stem cells by preventing the reuse of misfolded proteins.Interestingly,we found that upon heat stress,the MYB3R-like/RID2 module is repressed to reduce WUS transcript abundance through decapping of nascent WUS mRNA.This releases the inhibition of protein-folding capacity in stem cells and protects them from heat shock by eliminating misfolded protein aggregation.Taken together,our results reveal a strategic trade-off whereby plants reduce the accuracy of protein synthesis in exchange for the survival of stem cells at high temperatures.
基金supported financially by the National Natural Science Foundation of China(Grant NO.52378258,52108169)the Key R&D Project of Hubei Province of China(Grant NO.2020BAB060).
文摘This paper introduces a novel material,low-carbon high-strength recycled aggregate concrete(LCHRAC),developed by activating ground granulated blast-furnace slag(GGBS)and silica fume(SF)in an alkaline environment and integrating recycled aggregate.To evaluate its mechanical properties,uniaxial compressive tests were performed,systematically analyzing the effects of recycled concrete aggregate(RCA)substitution ratios,as well as the characteristic parameters of steel and polypropylene(PP)fibers,on LCHRAC’s mechanical behavior.The results indicated that compressive strength shows a gradual decline as the RCA substitution ratio increases,with a moderate reduction of 7.1%up to 50%replacement,and a more significant drop,retaining only 68.6%at 100%replacement.In contrast,the peak strain increases linearly,showing a 29%improvement at full replacement,while the toughness index exhibits a consistent upward trend,increasing by approximately 123%at a 100%replacement rate.Based on experimental data,empirical models were developed to predict the influence of key control variables on the compressive strength,peak strain,elastic modulus,and the uniaxial compressive stress-strain behavior of LCHRAC.Additionally,advanced characterization techniques,including X-ray diffraction(XRD),thermogravimetric analysis(TGA/DTG),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS),were employed to elucidate the hydration mechanisms of the slag-silica fume composite system.These findings provide a comprehensive understanding of the mechanical performance and microstructural characteristics of LCHRAC,contributing to its potential application in sustainable construction practices.
