Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels...Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels and mineralization remains limited.In this study,we summarize the deformation patterns and associated mineral deposits observed at different crustal levels(i.e.,surface,shallow,middle,and deep structural levels,corresponding to depths of<2,2-8,8-15,and>15 km,respectively).Furthermore,we examine the genetic association between structural levels and metallogenesis,demonstrating that distinct structural levels are linked to specific types of mineralization.Key factors that vary across crustal levels include temperature,pressure,and fluid circulation.Ore-forming processes involve interactions between structures and fluids under varying temperatures and pressures.Structural levels influence mineralization by controlling the temperatures,pressures,and deformation mechanisms that drive the activation,migration,and enrichment of ore-forming materials.展开更多
The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global se...The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global sea level rise [1]. If it melted completely, sea levels would climb 65 cm, and follow-on effects could lead to a 3 m increase [2]. But if some scientists' vision becomes reality, in 10–15 years construction crews will sail into the Amundsen Sea off Antarctica to begin building an 80 km long underwater curtain that will shield the glacier from the warm currents that are accelerating its decline [3].展开更多
BackgroundIt's crucial to study the effect of changes in thresholds(T)and most comfortable levels(M)on behavioral measurements in young children using cochlear implants.This would help the clinician with the optim...BackgroundIt's crucial to study the effect of changes in thresholds(T)and most comfortable levels(M)on behavioral measurements in young children using cochlear implants.This would help the clinician with the optimization and validation of programming parameters.ObjectiveThe study has attempted to describe the changes in behavioral responses with modification of T and M levels.MethodsTwenty-five participants in the age range 5 to 12 years using HR90K/HiFocus1J or HR90KAdvantage/HiFocus1J with Harmony speech processors participated in the study.A decrease in T levels,a rise in T levels,or a decrease in M levels in the everyday program were used to create experimental programs.Sound field thresholds and speech perception were measured at 50 dBHL for three experimental and everyday programs.ConclusionThe results indicated that only reductions of M levels resulted in significantly(p<0.01)poor aided thresholds and speech perception.On the other hand,variation in T levels did not have significant changes in either sound field thresholds or speech perception.The results highlight that M levels must be correctly established in order to prevent decreased speech perception and audibility.展开更多
For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models...For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models and physical models,each offering unique advantages but also facing limitations.Physics-informed neural networks(PINNs)provide a robust framework to integrate data-driven models with physical principles,ensuring consistency with underlying physics while enabling generalization across diverse operational conditions.This study introduces a PINN-based approach to reconstruct open circuit voltage(OCV)curves and estimate key ageing parameters at both the cell and electrode levels.These parameters include available capacity,electrode capacities,and lithium inventory capacity.The proposed method integrates OCV reconstruction models as functional components into convolutional neural networks(CNNs)and is validated using a public dataset.The results reveal that the estimated ageing parameters closely align with those obtained through offline OCV tests,with errors in reconstructed OCV curves remaining within 15 mV.This demonstrates the ability of the method to deliver fast and accurate degradation diagnostics at the electrode level,advancing the potential for precise and efficient battery health management.展开更多
Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study...Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study aims to survey the level of radiation doses delivered to child patients during head exams in CT imaging to set up the Dosimetric Reference Levels (DRLs), a routine dose optimization tool, based on data acquired at the University Hospital of Angré (UHA), the University Hospital of Treichville (UHT) and the Polyclinic Hospital Farah (Farah) for optimizing procedures in Ivorian hospitals. Prospectively performed on 334 CT images of 186 child patients, this study was carried out on CT systems such as Hitachi Scenaria, Sinovision Insitum, and Philips Incisive used respectively at UHA, UHT and Farah. Children’s scan data were classified into four age bands: vol or dose-length product as DLP) value, whatever the hospital, increases with respect to the age of child patients. Based on the 75th percentile of the whole dose distributions, the DRLs of the CTDIvol is 54.37 mGy whatever the age groups and those of the DLP with respect to age bands are 1224.55 mGy∙cm, 1414.06 mGy∙cm, 1632.24 mGy.cm and 1544.57 mGy∙cm, respectively. The averaged values of CTDIvol and DLP smaller than the corresponding DRLs values suggest that practices in our three facilities are optimized. However, comparing our results with those from different international studies, we see that the CTDIvol and DLP values obtained in the present work are higher. These results suggest additional surveys to ensure our DRLs values and efforts from radiologists, imaging technicians and medical physicists to strengthen clinical procedures for the radiation protection of children undergoing CT scans in Côte d’Ivoire.展开更多
Water level is the overriding control on carbon cycles in peatlands,which are important for global carbon cycles and ecosystem services.To date,our knowledge of the pattern of water level fluctuations in peatlands and...Water level is the overriding control on carbon cycles in peatlands,which are important for global carbon cycles and ecosystem services.To date,our knowledge of the pattern of water level fluctuations in peatlands and the influence of precipitation and air temperature on them in the subtropical remains poor.In this study,we conducted continuous high-resolution monitoring of water levels from 2014 to 2021 in the Dajiuhu peatland,a typically subtropical peatland in central China.Monitoring results showed that the water level had strong annual(370 days) and seasonal(130 days) oscillations in the Dajiuhu peatland.The annual oscillation is associated with both precipitation and temperature,while the seasonal oscillation is mainly controlled by precipitation.In addition,the depth of peat surface to the water table(DWT) has weak but significant correlations with precipitation and temperature on the daily and weekly scales(r = 0.1–0.21,p<0.01).Once replacing DWT with water table fluctuation cumulation,the correlation coefficients increase apparently(r = 0.47–0.69,p<0.01),especially on the monthly scale.These findings highlight a more important role of the fluctuation than the mean position of water level and have the potential to improve the interpretation of water-level related paleoenvironmental proxies and the understanding of the relationship between water level and biogeochemical processes.展开更多
The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, ...The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, including 10 radiologists working in the hospitals covered by the survey, to assess the practice of pediatric radiology and the degree of compliance with radiation protection principles for the safety of children and the environment. We collected radiophysical parameters to calculate entrance doses in pediatric radiology in radiology departments to determine the dosimetric level by comparison with the diagnostic reference levels of the International Commission on Radiological Protection (ICRP). All in all, we found that in Kongo Central in the DRC, many health personnel surveyed reported that more than 30% of requested radiological examinations are not justified. Also, after comparing the entrance doses produced in the surveyed departments with those of the International Commission on Radiological Protection (ICRP), a statistically significant difference was found in pediatric radiology between the average doses in five out of six surveyed departments and those of the ICRP. Therefore, almost all of the surveyed departments were found to be highly irradiating in children, while excessive X-ray irradiation in children can have significant effects due to their increased sensitivity to radiation. Among the risks are: increased cancer risks, damage to developing cells, potential genetic effects, and neurological effects. This is why support for implementing radiation protection principles is a necessity to promote the safety of patients and the environment against the harmful effects of X-rays in conventional radiology.展开更多
A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching...A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.展开更多
Objective:To explore the associations between income levels,employment risk,lifestyles,occupational stress,and male fertility.Methods:This cross-sectional study analyzed 294 men seeking fertility treatment at fertilit...Objective:To explore the associations between income levels,employment risk,lifestyles,occupational stress,and male fertility.Methods:This cross-sectional study analyzed 294 men seeking fertility treatment at fertility clinics in Terengganu,Pahang,and Kuala Lumpur from November 2021 to June 2023.Data were collected through structured questionnaires covering income levels,lifestyles,employment risks,occupational stress,and semen quality.Multinomial logistic regression was employed to assess predictors of semen quality,with crude and adjusted odds ratios(OR)reported.Results:The lower-income group exhibited higher odds of having abnormal semen quality compared to normal semen quality.Specifically,these participants were more likely to experience azoospermia[crude OR 6.68,95%confidence interval(CI)1.84-52.63;adjusted OR 6.26,95%CI 1.76-51.38],indicating a link between low income and infertility issues.Lifestyle factors did not show significant associations with semen abnormalities after adjustment.High employment risks had significant associations with oligozoospermia after adjustment(crude OR 5.50,95%CI 2.14-14.11;adjusted OR 5.15,95%CI 1.93-13.71),while high occupational stress was linked to asthenozoospermia(crude OR 2.26,95%CI 1.09-4.68;adjusted OR 2.25,95%CI 1.07-4.69).Conclusions:The findings underscore the influence of socioeconomic and occupational factors on male fertility,showing associations between lower income levels,high-risk occupations,and semen abnormalities.In contrast,lifestyle factors did not show significant associations with semen abnormalities after adjustment.Nevertheless,the current findings should be further confirmed through more extensive studies focusing on abnormal semen and lifestyle factors.展开更多
In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of...In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of life and aquatic ecosystems in the lower basin water bodies.Analyzing long-term trends in rainfall and water levels is crucial for enhancing our understanding.This study aims to examine the evolving patterns of water level and rainfall in the region.Data on water levels and rainfall from observation stations were gathered from the National Center for Hydrometeorological Forecasting,Vietnam,spanning from 2000 to 2014.The assessment of homogeneity and identification of trend changes were conducted using the Standard Normal Homogeneity Test(SNHT)and the Mann-Kendall test.The results indicate that changes in water levels at the Tan Chau and Chau Doc stations have been observed since 2010 due to the operation of flow-regulating structures in the upper Mekong River.Following the commencement of upstream dam operations,the water level at the headwater stations of the Mekong River has been higher than the long-term average during the dry season and lower than the average during the flood season.The study findings highlight the influence of altered rainfall patterns under the impact of climate variability(ICC)on water level trends in the study area.While rainfall plays a significant role in increasing water levels during the flood season,the operation of hydropower dams(UHDs)stands out as the primary factor driving water level reductions in the study area.展开更多
Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a r...Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a reliable temperature compensation method for the system,improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.Design/methodology/approach–Combined with theoretical analysis and experimental verification,the temperature compensation method is explored.The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula,the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived.The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.Findings–The experimental results show that this method can reduce the error of the static level monitoring system by about 40%.The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation,which has certain practicability.Originality/value–The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method.The accuracy of the system is improved,which provides a reference for slope stability monitoring under complex environment(especially railway geotechnical engineering)and promotes the development of precision monitoring technology.展开更多
Separation between water and land is vital for marine scientific research and coastal zone planning and management.The contrasting backscatter properties of land and ocean enable clear water edge line identification i...Separation between water and land is vital for marine scientific research and coastal zone planning and management.The contrasting backscatter properties of land and ocean enable clear water edge line identification in synthetic aperture radar(SAR)imagery.However,SAR images are prone to speckle noise,and the complexity of the water-land boundaries environment makes accurate water-land separation challenging.To overcome noise and complex background interference in remote sensing images,an improved level set method was employed to enhance water-land separation.In the traditional distance regularized level set method,the selection of the image correlation weight coefficient and the edge indicator function directly influences the accuracy of the final segmentation results.A novel level set segmentation algorithm incorporating an improved edge indicator function is proposed to efficiently and accurately separate the water edge lines in SAR images.The distance regularized level set evolution model is enhanced by incorporating the signed pressure force function as an adaptive parameter,which serves as an external constraint for curve evolution.A novel level set model with an adaptive edge indicator function,combining gradient and regional information,is proposed.Experimental results demonstrate that the proposed model enhances the accuracy of waterland separation in SAR images.However,further research is needed to evaluate its potential for detecting boundaries in diverse marine environments and across different types of SAR imagery.展开更多
Collaborative changes in the hydro-sediment regime and erosional base level are vital factors that influence the evolution of wandering rivers.In the wandering Xiaobeiganliu reach of the Middle Yellow River(MYR),the r...Collaborative changes in the hydro-sediment regime and erosional base level are vital factors that influence the evolution of wandering rivers.In the wandering Xiaobeiganliu reach of the Middle Yellow River(MYR),the rapidly decreasing sediment discharge and lowering base level,i.e.,the Tongguan elevation,have resulted in new features of thalweg migration in river morphology.In this work,on the basis of topographic measurements of the reach from 2003–2021,the thalweg migration distance and intensity were calculated at both the section scale and reach scale.The results revealed that the annual sediment discharge decreased by 72%from 1986–2002,and the reach exhibited sustained scouring from deposition,leading to the Tongguan elevation decreasing by 1.69 m compared with that in 2002.Accordingly,the distance and intensity of thalweg migration have been reduced to varying degrees in both section and reach scales.The maximum section-scale thalweg migration distance was reduced by 11%,whereas the average thalweg migration distance and intensity at the reach scale decreased by 14%and 43%,respectively.During this sustained scouring period,the fluvial erosion intensity at the reach scale increased as the sediment discharge decreased.However,because the base level remained high,riverbed undercutting was deeply limited,which exacerbated lateral erosion of the bank and floodplain,enhancing thalweg migration.Flow-sediment regulation and training can be coupled to increase undercutting efficiency in the main channel and to protect banks from lateral erosion in river reach management.展开更多
Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based ...Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.展开更多
A cylindrical chamber with a rotating bottom holds significant potential for application in cell culture bioreactors due to its ability to generate more stable swirling flows.In order to control vortex breakdown withi...A cylindrical chamber with a rotating bottom holds significant potential for application in cell culture bioreactors due to its ability to generate more stable swirling flows.In order to control vortex breakdown within the chamber,this study first establishes a computational fluid dynamics simulation coupled with the level set method.Verified by experimental results in literature,this method accurately simulates the position and shape of vortex breakdown,and also predicts the critical Reynolds numbers for the appearance and detachment of vortex breakdown bubbles from the center.Additionally,it precisely captures the gas-liquid interface and depicts the vortex breakdown phenomenon in the air above the liquid for the first time.Finally,it predicts the impact of physical property of gas-liquid systems on vortex breakdown in response to significant changes in viscosity of microbial process systems.展开更多
The optimization of hole transport layer(HTL)is crucial for achieving high efficiency and stability in inverted perovskite solar cells(PSCs)due to its role in facilitating hole transport and passivating the perovskite...The optimization of hole transport layer(HTL)is crucial for achieving high efficiency and stability in inverted perovskite solar cells(PSCs)due to its role in facilitating hole transport and passivating the perovskite bottom interface.While self-assembled monolayers(SAMs)are commonly used for this purpose,the inherent limitations of a single SAM,such as fixed energy levels and rigid structure,restrict their adaptability for different perovskite components and further efficiency enhancement.Here,we demonstrate a stepwise deposition method for SAM-based HTLs to address this issue.We regulated the energy level gradient by depositing two SAMs with distinct energy levels,while the interactions between the phosphate groups in the SAMs and perovskite effectively reduce defect density at the bottom interface of the perovskite film.The as-fabricated PSCs achieved enhanced efficiency and stability with PCEs of 25.7% and 24.0% for rigid and flexible PSCs,respectively;these devices maintain 90% of their initial PCE after 500 h of maximum power point tracking,and retain 98% of their initial PCE after 4,000 bending cycles,representing one of the most stable flexible PSCs reported to date.展开更多
BACKGROUND Colorectal cancer(CRC)has become the third leading cancer with the third highest occurrence rate and the second highest death ratio globally.Its incidence and mortality rates have been increasing annually i...BACKGROUND Colorectal cancer(CRC)has become the third leading cancer with the third highest occurrence rate and the second highest death ratio globally.Its incidence and mortality rates have been increasing annually in recent years,posing a serious threat to global public health.Digestive endoscopy technology can not only be used for the diagnosis of CRC,but it can also be used in determining the depth of infiltration in early CRC.There are significant deficiencies in care measures in this area.METHODS A total of 120 CRC patients were randomly and equally divided into a control group and an observation group.The patients in the control group received basic routine nursing care,and the patients in the observation group received sys-tematic digestive endoscopy center nursing care.The patients'compliance and nursing satisfaction were observed and recorded,as well as the Self-Rating Anxiety Scale(SAS),Self-Rating Depression Scale(SDS)and Visual Analogue Scale(VAS)scores.RESULTS After care,the SAS and SDS scale scores of patients in both groups significantly decreased compared to before care(P<0.05).The VAS scale scores significantly increased for each group compared to before examination(P<0.05).The SAS,SDS and VAS scale scores of the observation group were significantly lower than those of the control group after nursing care(P<0.05),and compliance and satisfaction of nursing care were significantly higher than those of the control group(P<0.05).CONCLUSION Digestive endoscopy center nursing can effectively intervene in and improve the psychological state and pain level of CRC patients,suggesting it is a valuable approach to adopt in the clinic.展开更多
基金supported by National Key Research and Development Program of China(Grant Nos.2022YFF0800903 and 2024YFC2909905)the National Natural Science Foundation of China(NSFC)(Grant Nos.42261144669,42262026,and 42273073).
文摘Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels and mineralization remains limited.In this study,we summarize the deformation patterns and associated mineral deposits observed at different crustal levels(i.e.,surface,shallow,middle,and deep structural levels,corresponding to depths of<2,2-8,8-15,and>15 km,respectively).Furthermore,we examine the genetic association between structural levels and metallogenesis,demonstrating that distinct structural levels are linked to specific types of mineralization.Key factors that vary across crustal levels include temperature,pressure,and fluid circulation.Ore-forming processes involve interactions between structures and fluids under varying temperatures and pressures.Structural levels influence mineralization by controlling the temperatures,pressures,and deformation mechanisms that drive the activation,migration,and enrichment of ore-forming materials.
文摘The Thwaites Glacier in western Antarctica(Fig. 1) keeps glaciologists and climate scientists awake at night. The 120 kmwide glacier loses about 45 billion tonnes of ice each year, accounting for about 4% of global sea level rise [1]. If it melted completely, sea levels would climb 65 cm, and follow-on effects could lead to a 3 m increase [2]. But if some scientists' vision becomes reality, in 10–15 years construction crews will sail into the Amundsen Sea off Antarctica to begin building an 80 km long underwater curtain that will shield the glacier from the warm currents that are accelerating its decline [3].
文摘BackgroundIt's crucial to study the effect of changes in thresholds(T)and most comfortable levels(M)on behavioral measurements in young children using cochlear implants.This would help the clinician with the optimization and validation of programming parameters.ObjectiveThe study has attempted to describe the changes in behavioral responses with modification of T and M levels.MethodsTwenty-five participants in the age range 5 to 12 years using HR90K/HiFocus1J or HR90KAdvantage/HiFocus1J with Harmony speech processors participated in the study.A decrease in T levels,a rise in T levels,or a decrease in M levels in the everyday program were used to create experimental programs.Sound field thresholds and speech perception were measured at 50 dBHL for three experimental and everyday programs.ConclusionThe results indicated that only reductions of M levels resulted in significantly(p<0.01)poor aided thresholds and speech perception.On the other hand,variation in T levels did not have significant changes in either sound field thresholds or speech perception.The results highlight that M levels must be correctly established in order to prevent decreased speech perception and audibility.
基金supported by the Beijing Natural Science Foundation(Grant No.L223013)。
文摘For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models and physical models,each offering unique advantages but also facing limitations.Physics-informed neural networks(PINNs)provide a robust framework to integrate data-driven models with physical principles,ensuring consistency with underlying physics while enabling generalization across diverse operational conditions.This study introduces a PINN-based approach to reconstruct open circuit voltage(OCV)curves and estimate key ageing parameters at both the cell and electrode levels.These parameters include available capacity,electrode capacities,and lithium inventory capacity.The proposed method integrates OCV reconstruction models as functional components into convolutional neural networks(CNNs)and is validated using a public dataset.The results reveal that the estimated ageing parameters closely align with those obtained through offline OCV tests,with errors in reconstructed OCV curves remaining within 15 mV.This demonstrates the ability of the method to deliver fast and accurate degradation diagnostics at the electrode level,advancing the potential for precise and efficient battery health management.
文摘Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study aims to survey the level of radiation doses delivered to child patients during head exams in CT imaging to set up the Dosimetric Reference Levels (DRLs), a routine dose optimization tool, based on data acquired at the University Hospital of Angré (UHA), the University Hospital of Treichville (UHT) and the Polyclinic Hospital Farah (Farah) for optimizing procedures in Ivorian hospitals. Prospectively performed on 334 CT images of 186 child patients, this study was carried out on CT systems such as Hitachi Scenaria, Sinovision Insitum, and Philips Incisive used respectively at UHA, UHT and Farah. Children’s scan data were classified into four age bands: vol or dose-length product as DLP) value, whatever the hospital, increases with respect to the age of child patients. Based on the 75th percentile of the whole dose distributions, the DRLs of the CTDIvol is 54.37 mGy whatever the age groups and those of the DLP with respect to age bands are 1224.55 mGy∙cm, 1414.06 mGy∙cm, 1632.24 mGy.cm and 1544.57 mGy∙cm, respectively. The averaged values of CTDIvol and DLP smaller than the corresponding DRLs values suggest that practices in our three facilities are optimized. However, comparing our results with those from different international studies, we see that the CTDIvol and DLP values obtained in the present work are higher. These results suggest additional surveys to ensure our DRLs values and efforts from radiologists, imaging technicians and medical physicists to strengthen clinical procedures for the radiation protection of children undergoing CT scans in Côte d’Ivoire.
基金supported by the National Natural Science Foundation of China(No.U20A2094)。
文摘Water level is the overriding control on carbon cycles in peatlands,which are important for global carbon cycles and ecosystem services.To date,our knowledge of the pattern of water level fluctuations in peatlands and the influence of precipitation and air temperature on them in the subtropical remains poor.In this study,we conducted continuous high-resolution monitoring of water levels from 2014 to 2021 in the Dajiuhu peatland,a typically subtropical peatland in central China.Monitoring results showed that the water level had strong annual(370 days) and seasonal(130 days) oscillations in the Dajiuhu peatland.The annual oscillation is associated with both precipitation and temperature,while the seasonal oscillation is mainly controlled by precipitation.In addition,the depth of peat surface to the water table(DWT) has weak but significant correlations with precipitation and temperature on the daily and weekly scales(r = 0.1–0.21,p<0.01).Once replacing DWT with water table fluctuation cumulation,the correlation coefficients increase apparently(r = 0.47–0.69,p<0.01),especially on the monthly scale.These findings highlight a more important role of the fluctuation than the mean position of water level and have the potential to improve the interpretation of water-level related paleoenvironmental proxies and the understanding of the relationship between water level and biogeochemical processes.
文摘The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, including 10 radiologists working in the hospitals covered by the survey, to assess the practice of pediatric radiology and the degree of compliance with radiation protection principles for the safety of children and the environment. We collected radiophysical parameters to calculate entrance doses in pediatric radiology in radiology departments to determine the dosimetric level by comparison with the diagnostic reference levels of the International Commission on Radiological Protection (ICRP). All in all, we found that in Kongo Central in the DRC, many health personnel surveyed reported that more than 30% of requested radiological examinations are not justified. Also, after comparing the entrance doses produced in the surveyed departments with those of the International Commission on Radiological Protection (ICRP), a statistically significant difference was found in pediatric radiology between the average doses in five out of six surveyed departments and those of the ICRP. Therefore, almost all of the surveyed departments were found to be highly irradiating in children, while excessive X-ray irradiation in children can have significant effects due to their increased sensitivity to radiation. Among the risks are: increased cancer risks, damage to developing cells, potential genetic effects, and neurological effects. This is why support for implementing radiation protection principles is a necessity to promote the safety of patients and the environment against the harmful effects of X-rays in conventional radiology.
基金supported by the National Natural Science Foundation of China(Grant No.12272144).
文摘A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.
基金supported by Malaysia's Ministry of Higher Education through the Fundamental Research Grant Scheme(FRGS)under the reference code FRGS/1/2020/SS0/UMT/02/3 and vote number 59637.
文摘Objective:To explore the associations between income levels,employment risk,lifestyles,occupational stress,and male fertility.Methods:This cross-sectional study analyzed 294 men seeking fertility treatment at fertility clinics in Terengganu,Pahang,and Kuala Lumpur from November 2021 to June 2023.Data were collected through structured questionnaires covering income levels,lifestyles,employment risks,occupational stress,and semen quality.Multinomial logistic regression was employed to assess predictors of semen quality,with crude and adjusted odds ratios(OR)reported.Results:The lower-income group exhibited higher odds of having abnormal semen quality compared to normal semen quality.Specifically,these participants were more likely to experience azoospermia[crude OR 6.68,95%confidence interval(CI)1.84-52.63;adjusted OR 6.26,95%CI 1.76-51.38],indicating a link between low income and infertility issues.Lifestyle factors did not show significant associations with semen abnormalities after adjustment.High employment risks had significant associations with oligozoospermia after adjustment(crude OR 5.50,95%CI 2.14-14.11;adjusted OR 5.15,95%CI 1.93-13.71),while high occupational stress was linked to asthenozoospermia(crude OR 2.26,95%CI 1.09-4.68;adjusted OR 2.25,95%CI 1.07-4.69).Conclusions:The findings underscore the influence of socioeconomic and occupational factors on male fertility,showing associations between lower income levels,high-risk occupations,and semen abnormalities.In contrast,lifestyle factors did not show significant associations with semen abnormalities after adjustment.Nevertheless,the current findings should be further confirmed through more extensive studies focusing on abnormal semen and lifestyle factors.
基金funded by the University of Science,VNU-HCM under grant number T2022-10 project entitled“Water level variability in the Mekong Delta under the impacts of anthropogenic and climatic factors”.
文摘In recent years,the water level in the Mekong Delta(MD)has undergone changes,attributed to the impacts of anthropogenic activities and climate change.Declining water levels have had implications for various aspects of life and aquatic ecosystems in the lower basin water bodies.Analyzing long-term trends in rainfall and water levels is crucial for enhancing our understanding.This study aims to examine the evolving patterns of water level and rainfall in the region.Data on water levels and rainfall from observation stations were gathered from the National Center for Hydrometeorological Forecasting,Vietnam,spanning from 2000 to 2014.The assessment of homogeneity and identification of trend changes were conducted using the Standard Normal Homogeneity Test(SNHT)and the Mann-Kendall test.The results indicate that changes in water levels at the Tan Chau and Chau Doc stations have been observed since 2010 due to the operation of flow-regulating structures in the upper Mekong River.Following the commencement of upstream dam operations,the water level at the headwater stations of the Mekong River has been higher than the long-term average during the dry season and lower than the average during the flood season.The study findings highlight the influence of altered rainfall patterns under the impact of climate variability(ICC)on water level trends in the study area.While rainfall plays a significant role in increasing water levels during the flood season,the operation of hydropower dams(UHDs)stands out as the primary factor driving water level reductions in the study area.
基金funded by the Scientific Research Project of China Academy of Railway Sciences Group Co.,Ltd(No.2024YJ332 and No.2024QT005)Scientific Research Special Project of China State Railway Group Co.,Ltd(No.TICSTR-2024-Ⅳ-007).
文摘Purpose–This study solves the key problem that the static level monitoring is susceptible to temperature interference and affects the accuracy in slope instability/deformation monitoring.The purpose is to develop a reliable temperature compensation method for the system,improve the accuracy of slope stability monitoring and provide support for improving the safety and safety monitoring of engineering spoil slope and other projects.Design/methodology/approach–Combined with theoretical analysis and experimental verification,the temperature compensation method is explored.The working principle of the hydrostatic leveling monitoring system is analyzed and the data processing formula,the temperature error calculation formula and the calculation formula for eliminating the error settlement value are derived.The temperature compensation method is established and verified by the field test of the engineering spoil slope which is disturbed by a debris flow.Findings–The experimental results show that this method can reduce the error of the static level monitoring system by about 40%.The field test shows that the fluctuation of slope settlement monitoring value is reduced after temperature compensation and the monitoring value is consistent with the actual situation,which has certain practicability.Originality/value–The originality of this study is to derive a theoretical formula for quantifying/eliminating temperature errors in static leveling and to establish a practical temperature compensation method.The accuracy of the system is improved,which provides a reference for slope stability monitoring under complex environment(especially railway geotechnical engineering)and promotes the development of precision monitoring technology.
基金The National Natural Science Foundation of China under contract Nos 61701416 and 61901195Natural Science Foundation of Jiangsu Province of China under contract No.BK20211341China Postdoctoral Science Foundation under contract No.2022M712687.
文摘Separation between water and land is vital for marine scientific research and coastal zone planning and management.The contrasting backscatter properties of land and ocean enable clear water edge line identification in synthetic aperture radar(SAR)imagery.However,SAR images are prone to speckle noise,and the complexity of the water-land boundaries environment makes accurate water-land separation challenging.To overcome noise and complex background interference in remote sensing images,an improved level set method was employed to enhance water-land separation.In the traditional distance regularized level set method,the selection of the image correlation weight coefficient and the edge indicator function directly influences the accuracy of the final segmentation results.A novel level set segmentation algorithm incorporating an improved edge indicator function is proposed to efficiently and accurately separate the water edge lines in SAR images.The distance regularized level set evolution model is enhanced by incorporating the signed pressure force function as an adaptive parameter,which serves as an external constraint for curve evolution.A novel level set model with an adaptive edge indicator function,combining gradient and regional information,is proposed.Experimental results demonstrate that the proposed model enhances the accuracy of waterland separation in SAR images.However,further research is needed to evaluate its potential for detecting boundaries in diverse marine environments and across different types of SAR imagery.
基金National Key R&D Program of China,No.2023YFC3206205National Natural Science Foundation of China,No.U22A20237Independent Research Project of Yellow River Engineering Consulting Co.,Ltd.,No.2025KY001。
文摘Collaborative changes in the hydro-sediment regime and erosional base level are vital factors that influence the evolution of wandering rivers.In the wandering Xiaobeiganliu reach of the Middle Yellow River(MYR),the rapidly decreasing sediment discharge and lowering base level,i.e.,the Tongguan elevation,have resulted in new features of thalweg migration in river morphology.In this work,on the basis of topographic measurements of the reach from 2003–2021,the thalweg migration distance and intensity were calculated at both the section scale and reach scale.The results revealed that the annual sediment discharge decreased by 72%from 1986–2002,and the reach exhibited sustained scouring from deposition,leading to the Tongguan elevation decreasing by 1.69 m compared with that in 2002.Accordingly,the distance and intensity of thalweg migration have been reduced to varying degrees in both section and reach scales.The maximum section-scale thalweg migration distance was reduced by 11%,whereas the average thalweg migration distance and intensity at the reach scale decreased by 14%and 43%,respectively.During this sustained scouring period,the fluvial erosion intensity at the reach scale increased as the sediment discharge decreased.However,because the base level remained high,riverbed undercutting was deeply limited,which exacerbated lateral erosion of the bank and floodplain,enhancing thalweg migration.Flow-sediment regulation and training can be coupled to increase undercutting efficiency in the main channel and to protect banks from lateral erosion in river reach management.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3005401)the National Natural Science Foundation of China(Grant No.52239009)。
文摘Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.
基金National Natural Science Foundation of China(22178228,22178326)
文摘A cylindrical chamber with a rotating bottom holds significant potential for application in cell culture bioreactors due to its ability to generate more stable swirling flows.In order to control vortex breakdown within the chamber,this study first establishes a computational fluid dynamics simulation coupled with the level set method.Verified by experimental results in literature,this method accurately simulates the position and shape of vortex breakdown,and also predicts the critical Reynolds numbers for the appearance and detachment of vortex breakdown bubbles from the center.Additionally,it precisely captures the gas-liquid interface and depicts the vortex breakdown phenomenon in the air above the liquid for the first time.Finally,it predicts the impact of physical property of gas-liquid systems on vortex breakdown in response to significant changes in viscosity of microbial process systems.
基金supported by the National Natural Science Foundation of China(22305119,12204234)the Natural Science Foundation of Jiangsu Province(BK20220878)+3 种基金the Fundamental Research Funds for the Central Universities(NS2023059)the China Postdoctoral Science Foundation(2022TQ0157,2023M741695)the Liaoning University Talent Introduction Research Startup Project(d295000048)the Center for Microscopy and Analysis of Nanjing University of Aeronautics and Astronautics for characterization support。
文摘The optimization of hole transport layer(HTL)is crucial for achieving high efficiency and stability in inverted perovskite solar cells(PSCs)due to its role in facilitating hole transport and passivating the perovskite bottom interface.While self-assembled monolayers(SAMs)are commonly used for this purpose,the inherent limitations of a single SAM,such as fixed energy levels and rigid structure,restrict their adaptability for different perovskite components and further efficiency enhancement.Here,we demonstrate a stepwise deposition method for SAM-based HTLs to address this issue.We regulated the energy level gradient by depositing two SAMs with distinct energy levels,while the interactions between the phosphate groups in the SAMs and perovskite effectively reduce defect density at the bottom interface of the perovskite film.The as-fabricated PSCs achieved enhanced efficiency and stability with PCEs of 25.7% and 24.0% for rigid and flexible PSCs,respectively;these devices maintain 90% of their initial PCE after 500 h of maximum power point tracking,and retain 98% of their initial PCE after 4,000 bending cycles,representing one of the most stable flexible PSCs reported to date.
文摘BACKGROUND Colorectal cancer(CRC)has become the third leading cancer with the third highest occurrence rate and the second highest death ratio globally.Its incidence and mortality rates have been increasing annually in recent years,posing a serious threat to global public health.Digestive endoscopy technology can not only be used for the diagnosis of CRC,but it can also be used in determining the depth of infiltration in early CRC.There are significant deficiencies in care measures in this area.METHODS A total of 120 CRC patients were randomly and equally divided into a control group and an observation group.The patients in the control group received basic routine nursing care,and the patients in the observation group received sys-tematic digestive endoscopy center nursing care.The patients'compliance and nursing satisfaction were observed and recorded,as well as the Self-Rating Anxiety Scale(SAS),Self-Rating Depression Scale(SDS)and Visual Analogue Scale(VAS)scores.RESULTS After care,the SAS and SDS scale scores of patients in both groups significantly decreased compared to before care(P<0.05).The VAS scale scores significantly increased for each group compared to before examination(P<0.05).The SAS,SDS and VAS scale scores of the observation group were significantly lower than those of the control group after nursing care(P<0.05),and compliance and satisfaction of nursing care were significantly higher than those of the control group(P<0.05).CONCLUSION Digestive endoscopy center nursing can effectively intervene in and improve the psychological state and pain level of CRC patients,suggesting it is a valuable approach to adopt in the clinic.
