Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessit...Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessitating the extensive use of in-situ monitoring to enable real-time adjustments of process parameters by detecting molten-pool features.To address the challenge of accurately extracting the molten-pool morphology from an undetached spatter,an innovative monitoring method based on the U-Net(U-shaped network)is proposed herein.A lightweight architecture accelerates the processing speed,whereas an enhanced loss function incorporating weight maps augments the segmentation precision.The model performance is evaluated by comparing its segmentation accuracy and processing speed with those of the conventional U-Net,using the mean intersection over union(MIoU)as the segmentation metric.The improved model demonstrates superior segmentation accuracy at the interface between the molten pool and spatter,with a peak MIoU of 0.9798 achieved on the test set.Furthermore,this model processes each image in an extremely short time of 17.9 ms.Using this segmentation algorithm,the error in extracting the molten-pool width from single-track experiments is within 0.1 mm.The proposed method for monitoring the molten-pool morphology is suitable for deployment in online monitoring systems,thus providing a foundation for subsequent process-parameter regulation.展开更多
Two-dimensional transition metal dichalcogenides(2D TMDCs)have received considerable attention in local strain engineering due to their extraordinary mechanical flexibility,electonic structure,and optical properties.T...Two-dimensional transition metal dichalcogenides(2D TMDCs)have received considerable attention in local strain engineering due to their extraordinary mechanical flexibility,electonic structure,and optical properties.The strain-induced out-of-plane deformations in 2D TMDCs lead to diverse excitonic behaviors and versatile modulations in optical properties,paving the way for the development of advanced quantum technologies,flexible optoelectronic materials,and straintronic devices.Research on local strain engineering on 2D TMDCs has been delved into fabrication techniques,electronic state variations,and quantum optical applications.This review begins by summarizing the state-of-the-art methods for introducing local strain into 2D TMDCs,followed by an exploration of the impact of local strain engineering on optical properties.The intriguing phenomena resulting from local strain,such as exciton funnelling and anti-funnelling,are also discussed.We then shift the focus to the application of locally strained 2D TMDCs as quantum emitters,with various strategies outlined for modulating the properties of TMDC-based quantum emitters.Finally,we discuss the remaining questions in this field and provide an outlook on the future of local strain engineering on 2D TMDCs.展开更多
Plant root systems,a crucial component of biogeotechnics,have been recognized as a promising and sustainable strategy to address novel challenges in geotechnical engineering,i.e.,climate change(Ng et al.,2022).Root-so...Plant root systems,a crucial component of biogeotechnics,have been recognized as a promising and sustainable strategy to address novel challenges in geotechnical engineering,i.e.,climate change(Ng et al.,2022).Root-soil composite and root-reinforced slopes have re-ceived widespread attention in recent decades,due to the ability of root to regulate soil properties through mechanical reinforcement and hy-draulic transpiration(Li&Duan,2023;Ni et al.,2024).Fig.1 provides a co-occurrence network plot of plant root-based soil reinforcement strategies published over the last decade,where three clusters are identified with different colors.On the left of the network map,clusters in red and blue are primarily driven by geotechnical investigations of vegetated slopes(i.e.,plant root reinforced slopes)and root-soil com-posite/root-permeated soils,as denoted by the terms like"model","test","slope","strength"and"vegetation",while the green cluster on the right side demonstrates botany-related domains,for instance,"plant growth",Indeed,the reinforcement of vegetated soil strength is com-plex and varies significantly with an abundance of factors,both me-chanically and hydraulically.Particularly,the impact of root mor-phology and architecture cannot be negligible,including keywords"root area ratio"root distribution""root morphology"root diame-ter"root density"in Fig.1 with the root size and root depth ranking foremost.展开更多
The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There i...The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There is a need to evaluate and enhance wildfire prediction methods,focusing on their application during extended periods of intense heat and drought.This study reviews various wildfire modelling approaches,including traditional physical,semi-empirical,numerical,and emerging machine learning(ML)-based models.We critically assess these models’capabilities in predicting fire susceptibility and post-ignition spread,highlighting their strengths and limitations.Our findings indicate that while traditional models provide foundational insights,they often fall short in dynamically estimating parameters and predicting ignition events.Cellular automata models,despite their potential,face challenges in data integration and computational demands.Conversely,ML models demonstrate superior efficiency and accuracy by leveraging diverse datasets,though they encounter interpretability issues.This review recommends hybrid modelling approaches that integrate multiple methods to harness their combined strengths.By incorporating data assimilation techniques with dynamic forecasting models,the predictive capabilities of ML-based predictions can be significantly enhanced.This review underscores the necessity for continued refinement of these models to ensure their reliability in real-world applications,ultimately contributing to more effective wildfire mitigation and management strategies.Future research should focus on improving hybrid models and exploring new data integration methods to advance predictive capabilities.展开更多
The discontinuation of denosumab[antibody targeting receptor activator of nuclear factor kappa B ligand(RANKL)]therapy may increase the risk of multiple vertebral fractures;however,the underlying pathophysiology is la...The discontinuation of denosumab[antibody targeting receptor activator of nuclear factor kappa B ligand(RANKL)]therapy may increase the risk of multiple vertebral fractures;however,the underlying pathophysiology is largely unknown.In patients who underwent discontinuation after multiple injections of denosumab,the levels of tartrate-resistant acid phosphatase 5b increased compared to pretreatment levels,indicating a phenomenon known as“overshoot.”The rate of decrease in bone mineral density during the withdrawal period was higher than the rate of decrease associated with aging,suggesting that the physiological bone metabolism had broken down.Overshoot and significant bone loss were also observed in mice receiving continuous administration of anti-RANKL antibody after treatment was interrupted,resembling the original pathology.In mice long out of overshoot,bone resorption recovered,but osteoblast numbers and bone formation remained markedly reduced.The bone marrow exhibited a significant reduction in stem cell(SC)antigen 1-and platelet-derived growth factor receptor alpha-expressing osteoblast progenitors(PαS cells)and alkaline phosphatase-positive early osteoblasts.Just before the overshoot phase,the osteoclast precursor cell population expands and RANKL-bearing extracellular vesicles(EVs)became abundant in the serum,leading to robust osteoclastogenesis after cessation of anti-RANKL treatment.Thus,accelerated bone resorption due to the accumulation of RANKLbearing EVs and long-term suppression of bone formation uncoupled from bone resorption leads to the severe bone loss characteristic of denosumab discontinuation.展开更多
The treatment of ammonia nitrogen wastewater(ANW)has garnered significant attention due to the ecology,and even biology is under increasing threat from over discharge ANW.Conventional ANW treatment methods often encou...The treatment of ammonia nitrogen wastewater(ANW)has garnered significant attention due to the ecology,and even biology is under increasing threat from over discharge ANW.Conventional ANW treatment methods often encounter challenges such as complex processes,high costs and secondary pollution.Considerable progress has been made in employing solar-induced evaporators for wastewater treatment.However,there remain notable barriers to transitioning from fundamental research to practical applications,including insufficient evaporation rates and inadequate resistance to biofouling.Herein,we propose a novel evaporator,which comprises a bio-enzyme-treated wood aerogel that serves as water pumping and storage layer,a cost-effective multi-walled carbon nanotubes coated hydrophobic/hydrophilic fibrous nonwoven mat functioning as photothermal evaporation layer,and aggregation-induced emission(AIE)molecules incorporated as anti-biofouling agent.The resultant bioinspired evaporator demonstrates a high evaporation rate of 12.83 kg m^(−2) h^(−1) when treating simulated ANW containing 30 wt%NH4Cl under 1.0 sun of illumination.AIE-doped evaporator exhibits remarkable photodynamic antibacterial activity against mildew and bacteria,ensuring outstanding resistance to biofouling over extended periods of wastewater treatment.When enhanced by natural wind under 1.0 sun irradiation,the evaporator achieves an impressive evaporation rate exceeding 20 kg m^(−2) h^(−1) .This advancement represents a promising and viable approach for the effective removal of ammonia nitrogen wastewater.展开更多
Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 20...Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 2008 （from Aug 27 to Sep 08）. Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy （SEM/EDX）. Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence （SRXRF）. Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 ± 2.18, 8.82 ± 3.52, and 2.02 ± 0.41 μg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.展开更多
Recent studies have shown that base-isolated objects with long fundamental natural periods are highly influenced by long-period earthquakes. These long-period waves result in large displacements for isolators, possibl...Recent studies have shown that base-isolated objects with long fundamental natural periods are highly influenced by long-period earthquakes. These long-period waves result in large displacements for isolators, possibly leading to exceedance of the allowable displacement limits. Conventional isolation systems, in general, fail to resist such large displacements. This has prompted the need to modify conventional base isolation systems. The current work focuses on the development of an external device, comprising a unit of negative and positive springs, for improving the performance of conventional base isolation systems. This unit accelerates the change in the stiffness of the isolation system where the stiffness of the positive spring varies linearly in terms of the displacement response of the isolated objects. The target objects of the present study are small structures such as computer servers, sensitive instruments and machinery. Numerical studies show that the increase in the damping of the system and the slope of the linear function is effective in reducing the displacement response. An optimal range of damping values and slope, satisfying the stability condition and the allowable limits of both displacement and acceleration responses when the system is subjected to near-fault and long-period ground motions simultaneously, is proposed.展开更多
The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of cro...The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of crop water consumption and net irrigation water consumption is crucial to guarantee the management of agricultural water resources. An actual crop evapotranspiration(ET) estimation model was proposed, by combining FAO Penman-Monteith method with remote sensing data. The planting area of winter wheat has a significant impact on water consumption; therefore, the planting area was also retrieved. The estimated ET showed good agreement with field-observed ET at four stations. The average relative bias and root mean square error(RMSE) for ET estimation were –2.2% and 25.5 mm, respectively. The results showed the planting area and water consumption of winter wheat had a decreasing trend in the Northern Hebei Plain(N-HBP) and Southern Hebei Plain(S-HBP). Moreover, in these two regions, there was a significant negative correlation between accumulated net irrigation water consumption and groundwater table. The total net irrigation water consumption in the N-HBP and S-HBP accounted for 12.9×10~9 m^3 and 31.9×10~9 m^3 during 2001–2016, respectively. Before and after 2001, the decline rate of groundwater table had a decreasing trend, as did the planting area of winter wheat in the N-HBP and S-HBP. The decrease of winter wheat planting area alleviated the decline of groundwater table in these two regions while the total net irrigation water consumption was both up to 28.5×10~9 m^3 during 2001–2016 in the Northwestern Shandong Plain(NW-SDP) and Northern Henan Plain(N-HNP). In these two regions, there was no significant correlation between accumulated net irrigation water consumption and groundwater table. The Yellow River was able to supply irrigation and the groundwater table had no significant declining trend.展开更多
Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen p...Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen peroxide by solar-light-driven oxidation of water by dioxygen and its usage as a green oxidant and fuel.The photocatalytic production of hydrogen peroxide is made possible by combining the e^(-)and 4e-oxidation of water with the e^(-)reduction of dioxygen using solar energy.The catalytic control of the selectivity of the e^(-)vs.4e-oxidation of water is discussed together with the selectivity of the e^(-)vs.4e-reduction of dioxygen.The combination of the photocatalytic e^(-)oxidation of water and the e^(-)reduction of dioxygen provides the best efficiency because both processes afford hydrogen peroxide.The solar-light-driven hydrogen peroxide production by oxidation of water and by reduction of dioxygen is combined with the catalytic oxidation of substrates with hydrogen peroxides,in which dioxygen is used as the greenest oxidant.展开更多
Past researchers have anticipated the occurrence of a great earthquake in the central Himalayas in the near future.This may cause serious damage in the Kathmandu Valley,which sits on an ancient lake bed zone,with lacu...Past researchers have anticipated the occurrence of a great earthquake in the central Himalayas in the near future.This may cause serious damage in the Kathmandu Valley,which sits on an ancient lake bed zone,with lacustrine sediments of more than 500 m depth.In this study,the predominant frequency of ground motion is evaluated using the Horizontal-to-Vertical (H/V) spectral ratio technique and recordings of ambient noise.The results of the H/V ratio show two peaks in about 20 percent of the locations,which are distributed mainly in and around the center and northern part of the Kathmandu Valley.The predominant frequencies vary from 0.5 Hz to 8.9 Hz in the study area,whereas the second resonance fiequency varies from 4 Hz to 6 Hz in the center and northern part of the valley.This indicates that the center and northern part of the valley have a wide range of resonance frequency due to two levels of impedance contrast- one may be from the surface layer and the other may be from the layer undemeath.These two levels of resonance indicate the importance of considering the effects of surface and lower layers during the planning and designing of infrastructures in the Kathmandu Valley.展开更多
Mass level of fine particles(PM2.5)in main cities in China has decreased significantly in recent years due to implementation of Chinese Clean Air Action Plan since 2013,however,03 pollution is getting worse than befor...Mass level of fine particles(PM2.5)in main cities in China has decreased significantly in recent years due to implementation of Chinese Clean Air Action Plan since 2013,however,03 pollution is getting worse than before,especially in megacities such as in Shanghai.In this work,O3 and PM2.5 were continuously monitored from May 27,2018 to March 31,2019.Our data showed that the annual average concentration of PM2.5 and O3(O3-8 hr,maximum8-hour moving average of ozone days)was 39.35±35.74 and 86.49±41.65μg/m3,respectively.The concentrations of PM2.5 showed clear seasonal trends,with higher concentrations in winter(83.36±18.66μg/m3)and lower concentrations in summer(19.85±7.23μg/m3),however,the seasonal trends of O3 were different with 103.75±41.77μg/m3 in summer and58.59±21.40μg/m3 in winter.Air mass backward trajectory,analyzing results of potential source contribution function model and concentration weighted trajectory model implied that pollutants from northwestern China contributed significantly to the mass concentration of Shanghai PM2.5,while pollutants from areas of eastern coastal provinces and South China Sea contributed significantly to the mass level of ozone in Shanghai atmosphere.Mass concentration of twenty-one elements in the PM2.5 were investigated,and their relationships with O3 were analyzed.Mass level of ozone had good correlation with that of Ba(r=0.64,p<0.05)and V(r=0.30,p>0.05),suggesting vehicle emission pollutants contribute to the increasing concentration of ozone in Shanghai atmosphere.展开更多
With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shieldin...With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.展开更多
To study the effects of different proportions of aluminum hydroxide and expandable graphite （EG） composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/ex...To study the effects of different proportions of aluminum hydroxide and expandable graphite （EG） composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/expandable graphite （ATH/EG） and silicone rubber composites were prepared by the compression molding method. The experimental results show that heat resistance improves with the increase of proportion of EG. Although the resistance coefficient changes, the composite materials still keep good electrical insulating property. Moreover, oxygen index and expansion index rise first then fall. When ATH/EG is 1：1, the oxygen index reaches the highest; the mechanical property of the silicone rubber is not affected under various environments such as acid, alkali, oily, artificial sea water environments, etc.展开更多
An integrally coupled wave-tide-surge model was developed and then applied to the simulation of the wave-typhoon surge for the typhoon Isewan （typhoon Vera （5915））, which is the strongest typhoon that has struck J...An integrally coupled wave-tide-surge model was developed and then applied to the simulation of the wave-typhoon surge for the typhoon Isewan （typhoon Vera （5915））, which is the strongest typhoon that has struck Japan and caused incalculable damage. An integrally coupled tide-surge-wave model using identical and homogeneous meshes in an unstructured grid system was used to correctly resolve the physics of wave-circulation interaction in both models. All model components were validated independently. The storm surge and wave properties such as the surge height, the significant wave height, wave period and direction were reproduced reasonably under the meteorological forcing, which was reprocessed to be close to the observations. The resulting modeling system can be used extensively for the prediction of the storm surge and waves and the usual barotropic forecast.展开更多
Ghrelin was isolated as an endogenous ligand for the GH secretagogue receptor from the rat stomach. Although physiological effects of ghrelin have been revealed by numerous studies, the regulation of stomach ghrelin r...Ghrelin was isolated as an endogenous ligand for the GH secretagogue receptor from the rat stomach. Although physiological effects of ghrelin have been revealed by numerous studies, the regulation of stomach ghrelin remains obscure, and the factor that directly regulates ghrelin expression and production has not been identified. Here, we show some data regarding the characteristic features of ghrelin cells and the regulation of stomach ghrelin. In the gastrointestinal tract, ghrelin cells were identified as opened- and closed-type cells, and it was found that the number of ghrelin cells decreased from the stomach to the colon. The postnatal change in number of ghrelin cells in the stomach showed a sexually dimorphic pattern, indicating a role of estrogen in the regulation of stomach ghrelin. In vitro studies revealed that estrogen stimulated both ghrelin expression and production and that treatment with formestane, an aromatase (estrogen synthetase) inhibitor, decreased ghrelin expression level. On the other hand, leptin was found to inhibit both basal and estrogen-stimulated ghrelin expression. Moreover, both aromatase mRNA- expressing cells and leptin cells were found to be located close to ghrelin cells in the gastric mucosa. Furthermore, we found an inverse relationship between gastric ghrelin and leptin levels in a fasting state, and we revealed relative changes in expression of gastric ghrelin, estrogen and leptin in the postnatal rats. We propose that gastric estrogen and leptin directly regulate stomach ghrelin and that the balance control through gastric estrogen and leptin contributes to the altered ghrelin expression level in some physiological states.展开更多
This work describes the development,optimisation and validation of an analytical method for the rapid determination of 17 priority pharmaceutical compounds and endocrine disrupting chemicals(EDCs).Rather than studying...This work describes the development,optimisation and validation of an analytical method for the rapid determination of 17 priority pharmaceutical compounds and endocrine disrupting chemicals(EDCs).Rather than studying compounds from the same therapeutic class,the analyses aimed to determine target compounds with the highest risk potential(with particular regard to Scotland),providing a tool for further monitoring in different water matrices.Prioritisation was based on a systematic environmental risk assessment approach,using consumption data;wastewater treatment removal efficiency;environmental occurrence;toxicological effects;and pre-existing regulatory indicators.This process highlighted 17 compounds across various therapeutic classes,which were then quantified,at environmentally relevant concentrations,by a single analytical methodology.Analytical determination was achieved using a single-step solid phase extraction(SPE)procedure followed by high-performance liquid chromatography with tandem mass spectrometry(HPLC-MS/MS).The fully optimised method performed well for the majority of target compounds,with recoveries>71%for 15 of 17 analytes.The limits of quantification for most target analytes(14 of 17)ranged from 0.07 ng/L to 1.88 ng/L in river waters.The utility of this method was then demonstrated using real water samples associated with a rural hospital/setting.Eight compounds were targeted and detected,with the highest levels found for the analgesic,paracetamol(at up to 105,910 ng/L in the hospital discharge).This method offers a robust tool to monitor high priority pharmaceutical and EDC levels in various aqueous sample matrices.展开更多
To improve the burial flux calculations of bioavailable phosphorus （P） and study opal-associated P （Opal-P） in the East China Sea （ECS）, surface and core sediments were collected in the Changjiang Estuary （CE）...To improve the burial flux calculations of bioavailable phosphorus （P） and study opal-associated P （Opal-P） in the East China Sea （ECS）, surface and core sediments were collected in the Changjiang Estuary （CE） and the south of the Cheju Island. In this study, sedimentary P was operationally divided into seven different forms using modified sedimentary extraction （SEDEX） technique： LSor-P （exchangeable or loosely sorbed P）, Fe-P （easily reducible or reactive ferric Fe-bound P）, CFA-P （authigenic carbonate fluorapatite and biogenic apatite and CaCO3-bound P）, Detr-P （detrital apatite）, Org-P （organic P）, Opal-P and Ref-P （refractory P）. The data revealed that the concentrations of the seven different P forms rank as Detr-P 〉 CFA-P 〉 Org-P 〉 Ref-P 〉 Opal-P 〉 Fe-P 〉 LSor-P in surface sediments and CFA-P 〉 Detr-P 〉 Org-P 〉 Ref-P 〉 Fe-P 〉 Opal-P 〉 LSor-P in core sediments. The distributions of the total phosphorus （TP）, TIP, CFA-P, Detr-P are similar and decrease from the CE to the south of the Cheju Island. Meanwhile, Org-P and Opal-P exhibit different distribution trends; this may be affected by the grain size and TOM. The concentrations of potentially bioavailable P are 9.6-13.0 μmol g^-1 and 10.0-13.6 μmol g^-1, representing 61%-70% and 41%？64% of the TP in surface and core sediments, respectively. The concentrations of Opal-P are 0.6-2.3 μmol g^-1 and 0.6-1.4 μmol g^-1 in surface and core sediments, ac-counting for 5.3%？19.8% and 4.2%？10.6% of bioavailable P, respectively. The total burial fluxes of Opal-P and bioavailable P are 1.4×10^9 mol y^-1 and 1.1×10^10 mol yr^-1 in the ECS, respectively. Opal-P represents about 12.7% of potentially bioavailable P, which should be recognized when studying P cycling in marine ecosystems.展开更多
Ficus (Moraceae) is a well-known group with specific pollination mutualisms, and hybridization is considered to be rare. Here, we report the presence of interspecific hybrids between Ficus pumila L. and F. thunbergii ...Ficus (Moraceae) is a well-known group with specific pollination mutualisms, and hybridization is considered to be rare. Here, we report the presence of interspecific hybrids between Ficus pumila L. and F. thunbergii Maxim. on Okinoshima, a small island offshore of Shikoku, western Japan. AFLP (amplified fragment length polymorphism of genomic DNA) data suggested that more than one-fourth of individuals of morphological F. pumila were assigned as intermediate genotypes, suggesting hybrids. The hybridization between the two species was introgressive and unidirectional from F. thunbergii to F. pumila. The findings of this study, combined with other previous reports, suggest that the breakdown of mutualistic systems can occur in isolated populations such as those on islands.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.52305440,52204263)Natural Science Foundation of Changsha City(Grant Nos.kq2208272,kq2208274)+1 种基金Tribology Science Fund of the State Key Laboratory of Tribology in Advanced Equipment(Grant SKLTKF22B09)National Key Research and Development Program of China(2022YFB3706902).
文摘Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessitating the extensive use of in-situ monitoring to enable real-time adjustments of process parameters by detecting molten-pool features.To address the challenge of accurately extracting the molten-pool morphology from an undetached spatter,an innovative monitoring method based on the U-Net(U-shaped network)is proposed herein.A lightweight architecture accelerates the processing speed,whereas an enhanced loss function incorporating weight maps augments the segmentation precision.The model performance is evaluated by comparing its segmentation accuracy and processing speed with those of the conventional U-Net,using the mean intersection over union(MIoU)as the segmentation metric.The improved model demonstrates superior segmentation accuracy at the interface between the molten pool and spatter,with a peak MIoU of 0.9798 achieved on the test set.Furthermore,this model processes each image in an extremely short time of 17.9 ms.Using this segmentation algorithm,the error in extracting the molten-pool width from single-track experiments is within 0.1 mm.The proposed method for monitoring the molten-pool morphology is suitable for deployment in online monitoring systems,thus providing a foundation for subsequent process-parameter regulation.
基金support from National Natural Science Foundation of China(Grant Nos.62205223)Natural Science Foundation of Guangdong Province(Grant Nos.2023A1515011455)+6 种基金Science and Technology Innovation Commission of Shenzhen(Grant Nos.20231121120748002)support from Guangdong Introducing Innovative and Entrepreneurial Teams(Grant Nos.2019ZT08L101)Natural Science Foundation of Guangdong Province(Grant Nos.2023A1515110091)Science and Technology Innovation Commission of Shenzhen(Grant Nos.JSGGKQTD20221101115701006)support from National Key R&D Program of China(Grant Nos.2021YFA1401100)National Natural Science Foundation of China(Grant Nos.12104317)Scientific Instrument Developing Project of Shenzhen University(Grant Nos.2023YQ003)。
文摘Two-dimensional transition metal dichalcogenides(2D TMDCs)have received considerable attention in local strain engineering due to their extraordinary mechanical flexibility,electonic structure,and optical properties.The strain-induced out-of-plane deformations in 2D TMDCs lead to diverse excitonic behaviors and versatile modulations in optical properties,paving the way for the development of advanced quantum technologies,flexible optoelectronic materials,and straintronic devices.Research on local strain engineering on 2D TMDCs has been delved into fabrication techniques,electronic state variations,and quantum optical applications.This review begins by summarizing the state-of-the-art methods for introducing local strain into 2D TMDCs,followed by an exploration of the impact of local strain engineering on optical properties.The intriguing phenomena resulting from local strain,such as exciton funnelling and anti-funnelling,are also discussed.We then shift the focus to the application of locally strained 2D TMDCs as quantum emitters,with various strategies outlined for modulating the properties of TMDC-based quantum emitters.Finally,we discuss the remaining questions in this field and provide an outlook on the future of local strain engineering on 2D TMDCs.
基金supported by Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-LZX0001)High-end Foreign Expert Introduction program(No.G2022165004L)+1 种基金High-end Foreign Expert Introduction program(No.DL2021165001L)The fi-nancial supports are gratefully acknowledged.
文摘Plant root systems,a crucial component of biogeotechnics,have been recognized as a promising and sustainable strategy to address novel challenges in geotechnical engineering,i.e.,climate change(Ng et al.,2022).Root-soil composite and root-reinforced slopes have re-ceived widespread attention in recent decades,due to the ability of root to regulate soil properties through mechanical reinforcement and hy-draulic transpiration(Li&Duan,2023;Ni et al.,2024).Fig.1 provides a co-occurrence network plot of plant root-based soil reinforcement strategies published over the last decade,where three clusters are identified with different colors.On the left of the network map,clusters in red and blue are primarily driven by geotechnical investigations of vegetated slopes(i.e.,plant root reinforced slopes)and root-soil com-posite/root-permeated soils,as denoted by the terms like"model","test","slope","strength"and"vegetation",while the green cluster on the right side demonstrates botany-related domains,for instance,"plant growth",Indeed,the reinforcement of vegetated soil strength is com-plex and varies significantly with an abundance of factors,both me-chanically and hydraulically.Particularly,the impact of root mor-phology and architecture cannot be negligible,including keywords"root area ratio"root distribution""root morphology"root diame-ter"root density"in Fig.1 with the root size and root depth ranking foremost.
基金funding enabled and organized by CAUL and its Member Institutions.
文摘The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There is a need to evaluate and enhance wildfire prediction methods,focusing on their application during extended periods of intense heat and drought.This study reviews various wildfire modelling approaches,including traditional physical,semi-empirical,numerical,and emerging machine learning(ML)-based models.We critically assess these models’capabilities in predicting fire susceptibility and post-ignition spread,highlighting their strengths and limitations.Our findings indicate that while traditional models provide foundational insights,they often fall short in dynamically estimating parameters and predicting ignition events.Cellular automata models,despite their potential,face challenges in data integration and computational demands.Conversely,ML models demonstrate superior efficiency and accuracy by leveraging diverse datasets,though they encounter interpretability issues.This review recommends hybrid modelling approaches that integrate multiple methods to harness their combined strengths.By incorporating data assimilation techniques with dynamic forecasting models,the predictive capabilities of ML-based predictions can be significantly enhanced.This review underscores the necessity for continued refinement of these models to ensure their reliability in real-world applications,ultimately contributing to more effective wildfire mitigation and management strategies.Future research should focus on improving hybrid models and exploring new data integration methods to advance predictive capabilities.
文摘The discontinuation of denosumab[antibody targeting receptor activator of nuclear factor kappa B ligand(RANKL)]therapy may increase the risk of multiple vertebral fractures;however,the underlying pathophysiology is largely unknown.In patients who underwent discontinuation after multiple injections of denosumab,the levels of tartrate-resistant acid phosphatase 5b increased compared to pretreatment levels,indicating a phenomenon known as“overshoot.”The rate of decrease in bone mineral density during the withdrawal period was higher than the rate of decrease associated with aging,suggesting that the physiological bone metabolism had broken down.Overshoot and significant bone loss were also observed in mice receiving continuous administration of anti-RANKL antibody after treatment was interrupted,resembling the original pathology.In mice long out of overshoot,bone resorption recovered,but osteoblast numbers and bone formation remained markedly reduced.The bone marrow exhibited a significant reduction in stem cell(SC)antigen 1-and platelet-derived growth factor receptor alpha-expressing osteoblast progenitors(PαS cells)and alkaline phosphatase-positive early osteoblasts.Just before the overshoot phase,the osteoclast precursor cell population expands and RANKL-bearing extracellular vesicles(EVs)became abundant in the serum,leading to robust osteoclastogenesis after cessation of anti-RANKL treatment.Thus,accelerated bone resorption due to the accumulation of RANKLbearing EVs and long-term suppression of bone formation uncoupled from bone resorption leads to the severe bone loss characteristic of denosumab discontinuation.
基金supported by the National Natural Science Foundation of China(52203226)the Fundamental Research Funds for the Central Universities(2232023G-06).
文摘The treatment of ammonia nitrogen wastewater(ANW)has garnered significant attention due to the ecology,and even biology is under increasing threat from over discharge ANW.Conventional ANW treatment methods often encounter challenges such as complex processes,high costs and secondary pollution.Considerable progress has been made in employing solar-induced evaporators for wastewater treatment.However,there remain notable barriers to transitioning from fundamental research to practical applications,including insufficient evaporation rates and inadequate resistance to biofouling.Herein,we propose a novel evaporator,which comprises a bio-enzyme-treated wood aerogel that serves as water pumping and storage layer,a cost-effective multi-walled carbon nanotubes coated hydrophobic/hydrophilic fibrous nonwoven mat functioning as photothermal evaporation layer,and aggregation-induced emission(AIE)molecules incorporated as anti-biofouling agent.The resultant bioinspired evaporator demonstrates a high evaporation rate of 12.83 kg m^(−2) h^(−1) when treating simulated ANW containing 30 wt%NH4Cl under 1.0 sun of illumination.AIE-doped evaporator exhibits remarkable photodynamic antibacterial activity against mildew and bacteria,ensuring outstanding resistance to biofouling over extended periods of wastewater treatment.When enhanced by natural wind under 1.0 sun irradiation,the evaporator achieves an impressive evaporation rate exceeding 20 kg m^(−2) h^(−1) .This advancement represents a promising and viable approach for the effective removal of ammonia nitrogen wastewater.
基金supported by the National Natural Science Foundation of China (No. 10775094, 40973072,41073073)the Shanghai Pujiang Talent Program,the Shanghai Committee of Science and Technology (No.10JC1405500)+1 种基金the Innovation Program of Shanghai Municipal Education Commission (No. 11ZZ80)the Shanghai Leading Academic Discipline Project (No.S30109)
文摘Ambient coarse particles （diameter 1.8-10 μm）, fine particles （diameter 0.1-1.8 μm）, and ultrafine particles （diameter 〈 0.1 μm） in the atmosphere of the city of Shanghai were sampled during the summer of 2008 （from Aug 27 to Sep 08）. Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy （SEM/EDX）. Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence （SRXRF）. Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 ± 2.18, 8.82 ± 3.52, and 2.02 ± 0.41 μg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.
文摘Recent studies have shown that base-isolated objects with long fundamental natural periods are highly influenced by long-period earthquakes. These long-period waves result in large displacements for isolators, possibly leading to exceedance of the allowable displacement limits. Conventional isolation systems, in general, fail to resist such large displacements. This has prompted the need to modify conventional base isolation systems. The current work focuses on the development of an external device, comprising a unit of negative and positive springs, for improving the performance of conventional base isolation systems. This unit accelerates the change in the stiffness of the isolation system where the stiffness of the positive spring varies linearly in terms of the displacement response of the isolated objects. The target objects of the present study are small structures such as computer servers, sensitive instruments and machinery. Numerical studies show that the increase in the damping of the system and the slope of the linear function is effective in reducing the displacement response. An optimal range of damping values and slope, satisfying the stability condition and the allowable limits of both displacement and acceleration responses when the system is subjected to near-fault and long-period ground motions simultaneously, is proposed.
基金National Natural Science Foundation of China,No.41471027National Key Research and Development Plan,No.2016YFC0401403
文摘The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of crop water consumption and net irrigation water consumption is crucial to guarantee the management of agricultural water resources. An actual crop evapotranspiration(ET) estimation model was proposed, by combining FAO Penman-Monteith method with remote sensing data. The planting area of winter wheat has a significant impact on water consumption; therefore, the planting area was also retrieved. The estimated ET showed good agreement with field-observed ET at four stations. The average relative bias and root mean square error(RMSE) for ET estimation were –2.2% and 25.5 mm, respectively. The results showed the planting area and water consumption of winter wheat had a decreasing trend in the Northern Hebei Plain(N-HBP) and Southern Hebei Plain(S-HBP). Moreover, in these two regions, there was a significant negative correlation between accumulated net irrigation water consumption and groundwater table. The total net irrigation water consumption in the N-HBP and S-HBP accounted for 12.9×10~9 m^3 and 31.9×10~9 m^3 during 2001–2016, respectively. Before and after 2001, the decline rate of groundwater table had a decreasing trend, as did the planting area of winter wheat in the N-HBP and S-HBP. The decrease of winter wheat planting area alleviated the decline of groundwater table in these two regions while the total net irrigation water consumption was both up to 28.5×10~9 m^3 during 2001–2016 in the Northwestern Shandong Plain(NW-SDP) and Northern Henan Plain(N-HNP). In these two regions, there was no significant correlation between accumulated net irrigation water consumption and groundwater table. The Yellow River was able to supply irrigation and the groundwater table had no significant declining trend.
基金supported by the JSPS KAKENHI(16H02268)from MEXTJapan and by the CRI(2012R1A3A2048842)Basic Science Research Program(NRF-2020R1I1A1A01074630)through NRF of Korea.
文摘Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen peroxide by solar-light-driven oxidation of water by dioxygen and its usage as a green oxidant and fuel.The photocatalytic production of hydrogen peroxide is made possible by combining the e^(-)and 4e-oxidation of water with the e^(-)reduction of dioxygen using solar energy.The catalytic control of the selectivity of the e^(-)vs.4e-oxidation of water is discussed together with the selectivity of the e^(-)vs.4e-reduction of dioxygen.The combination of the photocatalytic e^(-)oxidation of water and the e^(-)reduction of dioxygen provides the best efficiency because both processes afford hydrogen peroxide.The solar-light-driven hydrogen peroxide production by oxidation of water and by reduction of dioxygen is combined with the catalytic oxidation of substrates with hydrogen peroxides,in which dioxygen is used as the greenest oxidant.
文摘Past researchers have anticipated the occurrence of a great earthquake in the central Himalayas in the near future.This may cause serious damage in the Kathmandu Valley,which sits on an ancient lake bed zone,with lacustrine sediments of more than 500 m depth.In this study,the predominant frequency of ground motion is evaluated using the Horizontal-to-Vertical (H/V) spectral ratio technique and recordings of ambient noise.The results of the H/V ratio show two peaks in about 20 percent of the locations,which are distributed mainly in and around the center and northern part of the Kathmandu Valley.The predominant frequencies vary from 0.5 Hz to 8.9 Hz in the study area,whereas the second resonance fiequency varies from 4 Hz to 6 Hz in the center and northern part of the valley.This indicates that the center and northern part of the valley have a wide range of resonance frequency due to two levels of impedance contrast- one may be from the surface layer and the other may be from the layer undemeath.These two levels of resonance indicate the importance of considering the effects of surface and lower layers during the planning and designing of infrastructures in the Kathmandu Valley.
基金The National Natural Science Foundation of China(No.21477073)for supporting us to conduct this research
文摘Mass level of fine particles(PM2.5)in main cities in China has decreased significantly in recent years due to implementation of Chinese Clean Air Action Plan since 2013,however,03 pollution is getting worse than before,especially in megacities such as in Shanghai.In this work,O3 and PM2.5 were continuously monitored from May 27,2018 to March 31,2019.Our data showed that the annual average concentration of PM2.5 and O3(O3-8 hr,maximum8-hour moving average of ozone days)was 39.35±35.74 and 86.49±41.65μg/m3,respectively.The concentrations of PM2.5 showed clear seasonal trends,with higher concentrations in winter(83.36±18.66μg/m3)and lower concentrations in summer(19.85±7.23μg/m3),however,the seasonal trends of O3 were different with 103.75±41.77μg/m3 in summer and58.59±21.40μg/m3 in winter.Air mass backward trajectory,analyzing results of potential source contribution function model and concentration weighted trajectory model implied that pollutants from northwestern China contributed significantly to the mass concentration of Shanghai PM2.5,while pollutants from areas of eastern coastal provinces and South China Sea contributed significantly to the mass level of ozone in Shanghai atmosphere.Mass concentration of twenty-one elements in the PM2.5 were investigated,and their relationships with O3 were analyzed.Mass level of ozone had good correlation with that of Ba(r=0.64,p<0.05)and V(r=0.30,p>0.05),suggesting vehicle emission pollutants contribute to the increasing concentration of ozone in Shanghai atmosphere.
基金This work was financially supported by the National Natural Science Foundation of China(51725101,11727807,51672050,61790581,52102368,52101213)the Ministry of Science and Technology of China(973 Project No.2018YFA0209102)+6 种基金University Development Fund(UDF0100152)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(Grant No.2017ZT07C291)Shenzhen Science and Technology Program(Grant No.KQTD20170810141424366)China Postdoctoral Science Foundation(Grant No.2020M680085)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905)Science and Technology Department of Jiangsu Province of China(Grant No.BK20210261)Open access funding provided by Shanghai Jiao Tong University
文摘With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.
文摘To study the effects of different proportions of aluminum hydroxide and expandable graphite （EG） composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/expandable graphite （ATH/EG） and silicone rubber composites were prepared by the compression molding method. The experimental results show that heat resistance improves with the increase of proportion of EG. Although the resistance coefficient changes, the composite materials still keep good electrical insulating property. Moreover, oxygen index and expansion index rise first then fall. When ATH/EG is 1：1, the oxygen index reaches the highest; the mechanical property of the silicone rubber is not affected under various environments such as acid, alkali, oily, artificial sea water environments, etc.
基金supported by the China-Korea Cooperative Research Project funded by CKJORCa major project titled the development of the marine environmental impact prediction system funded by KIOSTsupported by the project of KISTI for the development of HPC-based management system against national-scale disaster
文摘An integrally coupled wave-tide-surge model was developed and then applied to the simulation of the wave-typhoon surge for the typhoon Isewan （typhoon Vera （5915））, which is the strongest typhoon that has struck Japan and caused incalculable damage. An integrally coupled tide-surge-wave model using identical and homogeneous meshes in an unstructured grid system was used to correctly resolve the physics of wave-circulation interaction in both models. All model components were validated independently. The storm surge and wave properties such as the surge height, the significant wave height, wave period and direction were reproduced reasonably under the meteorological forcing, which was reprocessed to be close to the observations. The resulting modeling system can be used extensively for the prediction of the storm surge and waves and the usual barotropic forecast.
基金Supported by (in part) Grants for research fellowships from the Japan Society for the Promotion of Science for Young Scientists by the Program for Promotion of Fundamental Studies in Health Sciences of the National Institute of Biomedical Innovation (NIBIO)
文摘Ghrelin was isolated as an endogenous ligand for the GH secretagogue receptor from the rat stomach. Although physiological effects of ghrelin have been revealed by numerous studies, the regulation of stomach ghrelin remains obscure, and the factor that directly regulates ghrelin expression and production has not been identified. Here, we show some data regarding the characteristic features of ghrelin cells and the regulation of stomach ghrelin. In the gastrointestinal tract, ghrelin cells were identified as opened- and closed-type cells, and it was found that the number of ghrelin cells decreased from the stomach to the colon. The postnatal change in number of ghrelin cells in the stomach showed a sexually dimorphic pattern, indicating a role of estrogen in the regulation of stomach ghrelin. In vitro studies revealed that estrogen stimulated both ghrelin expression and production and that treatment with formestane, an aromatase (estrogen synthetase) inhibitor, decreased ghrelin expression level. On the other hand, leptin was found to inhibit both basal and estrogen-stimulated ghrelin expression. Moreover, both aromatase mRNA- expressing cells and leptin cells were found to be located close to ghrelin cells in the gastric mucosa. Furthermore, we found an inverse relationship between gastric ghrelin and leptin levels in a fasting state, and we revealed relative changes in expression of gastric ghrelin, estrogen and leptin in the postnatal rats. We propose that gastric estrogen and leptin directly regulate stomach ghrelin and that the balance control through gastric estrogen and leptin contributes to the altered ghrelin expression level in some physiological states.
文摘This work describes the development,optimisation and validation of an analytical method for the rapid determination of 17 priority pharmaceutical compounds and endocrine disrupting chemicals(EDCs).Rather than studying compounds from the same therapeutic class,the analyses aimed to determine target compounds with the highest risk potential(with particular regard to Scotland),providing a tool for further monitoring in different water matrices.Prioritisation was based on a systematic environmental risk assessment approach,using consumption data;wastewater treatment removal efficiency;environmental occurrence;toxicological effects;and pre-existing regulatory indicators.This process highlighted 17 compounds across various therapeutic classes,which were then quantified,at environmentally relevant concentrations,by a single analytical methodology.Analytical determination was achieved using a single-step solid phase extraction(SPE)procedure followed by high-performance liquid chromatography with tandem mass spectrometry(HPLC-MS/MS).The fully optimised method performed well for the majority of target compounds,with recoveries>71%for 15 of 17 analytes.The limits of quantification for most target analytes(14 of 17)ranged from 0.07 ng/L to 1.88 ng/L in river waters.The utility of this method was then demonstrated using real water samples associated with a rural hospital/setting.Eight compounds were targeted and detected,with the highest levels found for the analgesic,paracetamol(at up to 105,910 ng/L in the hospital discharge).This method offers a robust tool to monitor high priority pharmaceutical and EDC levels in various aqueous sample matrices.
基金financially supported by the National Natural Science Foundation of China (Nos. 41530965, 41276071, 41003052)the Fundamental Research Funds for the Central Universities (No. 201564008)
文摘To improve the burial flux calculations of bioavailable phosphorus （P） and study opal-associated P （Opal-P） in the East China Sea （ECS）, surface and core sediments were collected in the Changjiang Estuary （CE） and the south of the Cheju Island. In this study, sedimentary P was operationally divided into seven different forms using modified sedimentary extraction （SEDEX） technique： LSor-P （exchangeable or loosely sorbed P）, Fe-P （easily reducible or reactive ferric Fe-bound P）, CFA-P （authigenic carbonate fluorapatite and biogenic apatite and CaCO3-bound P）, Detr-P （detrital apatite）, Org-P （organic P）, Opal-P and Ref-P （refractory P）. The data revealed that the concentrations of the seven different P forms rank as Detr-P 〉 CFA-P 〉 Org-P 〉 Ref-P 〉 Opal-P 〉 Fe-P 〉 LSor-P in surface sediments and CFA-P 〉 Detr-P 〉 Org-P 〉 Ref-P 〉 Fe-P 〉 Opal-P 〉 LSor-P in core sediments. The distributions of the total phosphorus （TP）, TIP, CFA-P, Detr-P are similar and decrease from the CE to the south of the Cheju Island. Meanwhile, Org-P and Opal-P exhibit different distribution trends; this may be affected by the grain size and TOM. The concentrations of potentially bioavailable P are 9.6-13.0 μmol g^-1 and 10.0-13.6 μmol g^-1, representing 61%-70% and 41%？64% of the TP in surface and core sediments, respectively. The concentrations of Opal-P are 0.6-2.3 μmol g^-1 and 0.6-1.4 μmol g^-1 in surface and core sediments, ac-counting for 5.3%？19.8% and 4.2%？10.6% of bioavailable P, respectively. The total burial fluxes of Opal-P and bioavailable P are 1.4×10^9 mol y^-1 and 1.1×10^10 mol yr^-1 in the ECS, respectively. Opal-P represents about 12.7% of potentially bioavailable P, which should be recognized when studying P cycling in marine ecosystems.
文摘Ficus (Moraceae) is a well-known group with specific pollination mutualisms, and hybridization is considered to be rare. Here, we report the presence of interspecific hybrids between Ficus pumila L. and F. thunbergii Maxim. on Okinoshima, a small island offshore of Shikoku, western Japan. AFLP (amplified fragment length polymorphism of genomic DNA) data suggested that more than one-fourth of individuals of morphological F. pumila were assigned as intermediate genotypes, suggesting hybrids. The hybridization between the two species was introgressive and unidirectional from F. thunbergii to F. pumila. The findings of this study, combined with other previous reports, suggest that the breakdown of mutualistic systems can occur in isolated populations such as those on islands.
