Two selenium(Se)-containing peptides from Se-enriched rice,TSeMMM and SeMDPGQQ,possess neuroprotective potency against lead(Pb2+)-induced cytotoxicity.However,the crosstalk between mRNA and microRNAs(miRNA)involved in...Two selenium(Se)-containing peptides from Se-enriched rice,TSeMMM and SeMDPGQQ,possess neuroprotective potency against lead(Pb2+)-induced cytotoxicity.However,the crosstalk between mRNA and microRNAs(miRNA)involved in the neuroprotection mechanism remains to be elucidated.In this study,RNA-sequencing and miRNA-sequencing were used to independently identify differentially expressed mRNAs and small RNAs profiles in Pb^(2+)-treated primary fetal rat cortical neurons and then the correlated miRNA-mRNA target pairs were obtained.It was found that 34 mRNAs related to oxidative phosphorylation could be reversed by pretreatment of TSeMMM and SeMDPGQQ.The protective effect of TSeMMM and SeMDPGQQ was mediated by upregulation of miR-107-3p,which downregulates the ATPase H+transporting V0 subunit e1(Atp6v0e1)mRNA level.A zebrafish model was applied to verify the relevance between the targeted mRNA and miRNA by real-time quantitative PCR.The results indicated that miR-107-3p was a potential therapeutic target to achieve neuroprotection of Se-containing peptides via stimulation of Atp6v0e1.展开更多
Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other wor...Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.展开更多
Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage admini...Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.展开更多
Perovskite solar cells(PSCs)emerge as the most promising photovoltaics(PV)for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies.The printed PSC...Perovskite solar cells(PSCs)emerge as the most promising photovoltaics(PV)for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies.The printed PSCs with simplified device architecture and fabrication procedures could further enhance the competitive strength of PSC technology.In this work,we present an in-situ defect passivation(ISDP)assisted full-printing of high performance formamidine-lead bromide(FAPbBr_(3))PSCs.Only three rapid printing steps are involved for electron transporting layer(ETL),perovskite and carbon to form a complete solar cell on the low-cost fluorine-doped tin oxide(FTO)substrate.Long-chain polymer monomethyl ether polyethylene glycol is particularly utilized as the ISDP passivator,leading to conformal coating on the rough FTO and defect passivation for both ETL and perovskite during printing.A high efficiency of 10.85%(certified 10.14%)and a high V_(oc)up to 1.57 V are achieved for the printed device.The unencapsulated PSCs maintain above 90%of the initial efficiency after continuously heating at 85℃for 1000 h and over 80%of the efficiency after the maximum power point tracking for 3500 h.The fully printed semitransparent PSCs with carbon grids(CGs)show average visible light transmittance over 33%and an efficiency of 8.81%.展开更多
Aim: Lead aprons are used to protect against scattered radiation from the patient during interventional procedures and certain special conventional radiological examinations. Given the importance of the role lead apro...Aim: Lead aprons are used to protect against scattered radiation from the patient during interventional procedures and certain special conventional radiological examinations. Given the importance of the role lead aprons are supposed to play in radiation protection, we propose to assess their conformity in medical imaging departments in public and religious hospitals in Togo. Materials and method: A multi-centre survey conducted from 26 November to 06 December 2021 in the radiology departments of public and religious health facilities in Togo. All aprons in use were included. The evaluation criteria were physical (visual), quantitative (radiographic) and qualitative (dosimetric). Results: We had registred 43 aprons among wich 27 (62.79%) leaded aprons were labelled non-compliant and 16 (37.21%) were labelled compliant. Of the aprons judged to be non-compliant, 70.37% were more than 10 years old and 96.30% showed defects on the radiographic images. The most common defects were vampire marks (18.64%), multiple folds (16.96%), cracks (16.96%), multiple cracks (15.25%), tears (8.47%), absence of lead (5.08%), holes (3.39%) and lead corrosion (1.69%). Defective aprons (62.96%) had at least two defects. The defects were of thoraco-abdomino-pelvic (74.07%), thoracic (14.82%) and abdomino-pelvic (11.11%) topography. For indirect exposure at 50 and 70 kilovolts, all the aprons had an attenuation factor greater than 90%. After dosimetric measurement, 13.95% of aprons had attenuation factors below 90% for indirect exposure at 100 kilovolts. Conclusion: The compliance of the leaded decks is trifactorial (physical, radiographic and dosimetric). However, there is no significant difference in X-ray attenuation capacity between defective and normal decks.展开更多
Perforation of the right ventricle during placement of pacing wires is a welldocumented complication and can be potentially fatal.Use of temporary pacemaker,helical screw leads and steroids use prior to implant are re...Perforation of the right ventricle during placement of pacing wires is a welldocumented complication and can be potentially fatal.Use of temporary pacemaker,helical screw leads and steroids use prior to implant are recognised as risk factors for development of post-permanent pacemaker effusion.We reported an unusual case of pacing wire perforating interventricular septum into the left ventricle that occurred during the implant procedure performed in another institution.After the preoperative work-up and transfer to our tertiary cardiothoracic centre,the patient underwent successful surgical management.In conclusion,early recognition and timely diagnosis using advanced multimodality imaging can guide surgical intervention and prevent unfavourable consequences of device-related complications.展开更多
Drought events have become more frequent and intense over East Asia in recent decades,leading to huge socioeconomic impacts.Although the droughts have been studied extensively by cases or for individual regions,their ...Drought events have become more frequent and intense over East Asia in recent decades,leading to huge socioeconomic impacts.Although the droughts have been studied extensively by cases or for individual regions,their leading variability and associated causes remain unclear.Based on the Standardized Precipitation Evapotranspiration Index(SPEI)and ERA5 reanalysis product from 1979 to 2020,this study evealuates the severity of spring droughts in East Asia and investigates their variations and associated drivers.The results indicate that North China and Mongolia have experienced remarkable trends toward dryness during spring in recent decades,while southwestern China has witnessed an opposite trend toward wetness.The first Empirical Orthogonal Function mode of SPEI variability reveals a similar seesawing pattern,with more severe dryness in northwestern China,Mongolia,North China,South Korea,and Japan but increased wetness in Southwestern China and southeast Asia.Further investigation reveals that the anomalously dry(wet)surface in North(Southwestern)China is significantly associated with anomalously high(low)temperature,less(more)precipitation,and reduced(increased)soil moisture during the previous winter and early spring,regulated by an anomalous anticyclone(cyclone)and thus reduced(increased)water vapor convergence.The spring dry-wet pattern in East Asia is also linked to cold sea surface temperature anomalies in the central-eastern Pacific.The findings of this study have important implications for improving the prediction of spring drought events in East Asia.展开更多
Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological foreca...Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well known.In this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are investigated.With increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal variations.In general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary particles.In spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural dust.In summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation rate.In autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.展开更多
The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on ...The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on the Reynolds Averaged Navier-Stokes equations(RANS).The results indicate that when sand-induced holes and small pits are involved as leading edge wear features,they have a minimal influence on the lift and drag coefficients of the airfoil.However,if delamination occurs in the same airfoil region,it significantly impacts the lift and resistance characteristics of the airfoil.Specifically,as the angle of attack grows,there is a significant decrease in the lift coefficient accompanied by a sharp increase in the drag coefficient.As wear intensifies,these effects gradually increase.Moreover,the leading edge wear can exacerbate flow separation near the trailing edge suction surface of the airfoil and cause forward displacement of the separation point.展开更多
A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effec...A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.展开更多
In accordance with the pattern of"great ideology and politics",the Party and youth League organizations assume the role of vanguard in the organization of colleges and universities.Simultaneously,they serve ...In accordance with the pattern of"great ideology and politics",the Party and youth League organizations assume the role of vanguard in the organization of colleges and universities.Simultaneously,they serve as a pivotal force in ideological and political education.In order to construct a comprehensive ideological and political framework encompassing the entire educational process,it is of paramount importance to identify an efficacious methodology for Party building leading League construction.This paper employs a comprehensive analysis to elucidate the pivotal role of Party building leading League construction in facilitating ideological and political education.It also illuminates the practical challenges encountered in the implementation of Party building leading League construction initiatives within colleges and universities.The article proposes a specific path for Party building leading League construction in colleges and universities based on three key aspects:cohesion of the consensus of Party building leading League building,establishment of the institutional system of Party building leading League construction,and creation of the model brand of Party building leading League construction.The aim is to promote in-depth development of Party building in colleges and universities and enhance the quality and effect of ideological and political education.展开更多
This article analyzes the role of oxygen in lead zinc metallurgy,including shortening the metallurgical process,promoting energy conservation and environmental protection,improving metallurgical strength,enhancing raw...This article analyzes the role of oxygen in lead zinc metallurgy,including shortening the metallurgical process,promoting energy conservation and environmental protection,improving metallurgical strength,enhancing raw material adaptability,and enhancing comprehensive recovery efficiency.This article introduces different lead zinc metallurgical processes and their oxygen consumption characteristics,including oxygen enriched side blowing lead smelting,oxygen bottom blowing lead smelting,oxygen enriched top blowing lead smelting,flash smelting lead,oxygen pressure leaching zinc smelting,and atmospheric pressure oxygen leaching zinc smelting.It is pointed out that oxygen enhanced metallurgy is the direction for the transformation and upgrading of lead zinc metallurgy.展开更多
Although there are many lead-free soldering alloys on the market, none of them have ideal qualities. The researchers are combining binary alloys with a variety of additional materials to create the soldering alloys’ ...Although there are many lead-free soldering alloys on the market, none of them have ideal qualities. The researchers are combining binary alloys with a variety of additional materials to create the soldering alloys’ features. The eutectic Sn-9Zn alloy is among them. This paper investigated the mechanical and electrical properties of Sn-9Zn-x (Ag, Cu, Sb);{x = 0.2, 0.4, and 0.6} lead-free solder alloys. The mechanical properties such as elastic modulus, ultimate tensile strength (UTS), yield strength (YS), and ductility were examined at the strain rates in a range from 4.17 10−3 s−1 to 208.5 10−3 s−1 at room temperature. It is found that increasing the content of the alloying elements and strain rate increases the elastic modulus, ultimate tensile strength, and yield strength while the ductility decreases. The electrical conductivity of the alloys is found to be a little smaller than that of the Sn-9Zn eutectic alloy.展开更多
The emergence of perovskite solar cells(PSCs) has greatly promoted the progress of photovoltaic technologies.The rapid development of PSCs has been driven by the advances in optimizing perovskite films and their adjac...The emergence of perovskite solar cells(PSCs) has greatly promoted the progress of photovoltaic technologies.The rapid development of PSCs has been driven by the advances in optimizing perovskite films and their adjacent interfaces.However,the polycrystalline perovskite layers in most highly efficient PSCs still contain various defects that greatly limit photovoltaic performance and stability of the devices.Herein,we introduce a multifunctional additive ethylene diamine tetra methylene phosphonic sodium(EDTMPS) with multiple anchor points into the precursor of perovskite to improve the efficiency and stability of PSCs and provide in-situ protection of lead leakage.The addition of EDTMPS acts as a crystal growth controller and passivation agent for perovskite films,thereby slowing down the crystallization rate of the film and obtaining high-quality perovskite films.Our study also provides an insight into how the modifier modulate the interfacial energy level arrangement as well as affect transfer of charge carriers and their recombination under photoinduced excitation.As a result,the power conversion efficiency(PCE) of single subcell with a working area of 0.255 cm^(2) increases significantly from 20.03% to 23.37%.Moreover,we obtained a PCE of 19.16% for the 25 cm^(2) module.Importantly,the unencapsulated EDTMP-modified PSCs exhibit better operational and thermal stability,as well as in-situ absorption of leaked lead ions.展开更多
Despite the high efficiency that has been achieved for the perovskite solar cells(PSCs),the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into...Despite the high efficiency that has been achieved for the perovskite solar cells(PSCs),the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into the commercial market for a large-scale installation.Herein,we report a novel low-cost and biodegradable lead sequestration layer with high compatibility for up-scalable encapsulation of PSCs.Through a precisely designed cross-linking reaction of chemical agents,the as-made biodegradable chitosan composite film shows enhanced mechanical strength,chemical stability,and lead adsorption capacity.The designed encapsulation strategy reduces over 99.99% lead leakage to <2 ppb under varied simulations of weather conditions(hail,rain,or flood),which meet the safe level of drinking water set by the US Environmental Protection Agency(EPA).Moreover,the PSC efficiency is improved from 21.91% to22.82% due to the improved light absorption from the printed biodegradable lead absorption film.Finally,we present a prototype process of accumulation and recycling of lead compounds in PSCs derbies via the biodegradation process.Based on the low-cost biodegradable lead sequestration film,this environmental-friendly encapsulation strategy could address the lead leakage issue for further commercialization of PSCs.展开更多
This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the...This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the penetrable data surface were used for noise prediction. The results showed that the three kinds of wave leading edge blades were effective in reducing the rotor-stator interaction tonal noise and also have a certain inhibitory effect on broadband noise. The A10W15 stator blade can effectively reduce broadband noise in the frequency range of 2200 - 4200 Hz. When the amplitude is increased to 20, the noise reduction effect is further enhanced. However, when the amplitude is increased to 30, the broadband noise reduction effect is no longer significant. Further research shows that the wave leading edge stator blades can significantly change the pressure fluctuation distribution on the leading edge and suction surface, which control the modal energy distribution. Finally, this paper analyzed multiple factors affecting the broadband noise reduction, such as the noise source cut-off and cut-on effect and correlation. The purpose of this paper is to explore the laws of the influence of wave leading edge blades on the duct noise of real fan, and to reveal its noise control mechanism. .展开更多
The dynamical prediction of the Asian-Australian monsoon(AAM)has been an important and long-standing issue in climate science.In this study,the predictability of the first two leading modes of the AAM is studied using...The dynamical prediction of the Asian-Australian monsoon(AAM)has been an important and long-standing issue in climate science.In this study,the predictability of the first two leading modes of the AAM is studied using retrospective prediction datasets from the seasonal forecasting models in four operational centers worldwide.Results show that the model predictability of the leading AAM modes is sensitive to how they are defined in different seasonal sequences,especially for the second mode.The first AAM mode,from various seasonal sequences,coincides with the El Niño phase transition in the eastern-central Pacific.The second mode,initialized from boreal summer and autumn,leads El Niño by about one year but can exist during the decay phase of El Niño when initialized from boreal winter and spring.Our findings hint that ENSO,as an early signal,is conducive to better performance of model predictions in capturing the spatiotemporal variations of the leading AAM modes.Still,the persistence barrier of ENSO in spring leads to poor forecasting skills of spatial features.The multimodel ensemble(MME)mean shows some advantage in capturing the spatiotemporal variations of the AAM modes but does not provide a significant improvement in predicting its temporal features compared to the best individual models in predicting its temporal features.The BCC_CSM1.1M shows promising skill in predicting the two AAM indices associated with two leading AAM modes.The predictability demonstrated in this study is potentially useful for AAM prediction in operational and climate services.展开更多
Milk is one of the very important nutrients of human diet. The presence of toxic elements in milk may threaten the public health. This study reports the levels of Cadmium (Cd), Cobalt (Co) and Lead (Pb) in raw cow’s ...Milk is one of the very important nutrients of human diet. The presence of toxic elements in milk may threaten the public health. This study reports the levels of Cadmium (Cd), Cobalt (Co) and Lead (Pb) in raw cow’s milk collected from different areas of Zanzibar Island during March - May 2016. The samples of raw milk were analyzed by Thermo Scientific-Atomic Absorption Spectrophotometer for quantitative determination of the metals in the matrix. The concentration of Co in this study ranged from ND at Mwanakwerekwe (MK1 and MK2) to a maximum of 0.004 mg/L at Mshelishelini (MS5) and Fuoni (F5) sites with mean concentration of 0.020 ± 0.003 mg/L for all sites. Concentration of Pb ranged between 0.05 - 0.51 mg/L at Fuoni (F7) and Mwanakwerekwe (MK1) respectively, with mean concentration of 0.263 ± 0.031 mg/L for all sites. However, Cd was only detected in one sample collected at Fuoni (F3) with a concentration of 0.001 mg/L. The results revealed that cow’s milk is contaminated with toxic metals, particularly Pb which exceeded the WHO maximum permissible level of 0.02 mg/L. The study furthermore sheds light on possible consequences to public health. It is recommended that, stakeholders especially in Zanzibar such as Zanzibar Food and Drug Authorities (ZFDA) and Zanzibar Bureau of Standards (ZBS) as well as researchers, use the findings of this study for policy making, future study plans, formulation of technical strategies to control milk contamination, risk assessment and develop new alternative methods to measure milk contamination even at a low detection limit for the sake of the consumers’ welfare before posing any serious effects to their health.展开更多
基金supported by the National Natural Science Foundation of China(32272319,31972020,32202032)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Two selenium(Se)-containing peptides from Se-enriched rice,TSeMMM and SeMDPGQQ,possess neuroprotective potency against lead(Pb2+)-induced cytotoxicity.However,the crosstalk between mRNA and microRNAs(miRNA)involved in the neuroprotection mechanism remains to be elucidated.In this study,RNA-sequencing and miRNA-sequencing were used to independently identify differentially expressed mRNAs and small RNAs profiles in Pb^(2+)-treated primary fetal rat cortical neurons and then the correlated miRNA-mRNA target pairs were obtained.It was found that 34 mRNAs related to oxidative phosphorylation could be reversed by pretreatment of TSeMMM and SeMDPGQQ.The protective effect of TSeMMM and SeMDPGQQ was mediated by upregulation of miR-107-3p,which downregulates the ATPase H+transporting V0 subunit e1(Atp6v0e1)mRNA level.A zebrafish model was applied to verify the relevance between the targeted mRNA and miRNA by real-time quantitative PCR.The results indicated that miR-107-3p was a potential therapeutic target to achieve neuroprotection of Se-containing peptides via stimulation of Atp6v0e1.
基金financially supported by the National Natural Science Foundation of China(U21A2078,22179042,and 12104170)the Natural Science Foundation of Fujian Province(2020J06021 and 2020J01064)Scientific Research Funds of Huaqiao University(23BS109)。
文摘Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.
基金supported by the National Key Research and Development Program of China under Grant(2022YFF1102800)the Graduate Scientific Research Innovation Project of Tianji(2022SKY109)+1 种基金the Project of Tianjin Science and Technology Program(22JCYBJC00360)the Project of Tianjin Science and Technology Program(21ZYJDJC00060)。
文摘Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.
基金financially supported by the Guangdong Pearl River Talent Program (2021ZT09L400)National Natural Science Foundation of China (52072284, 21875178, 91963209)the Joint Funds of Natural Science Foundation of Hubei Province (2022CFD087)
文摘Perovskite solar cells(PSCs)emerge as the most promising photovoltaics(PV)for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies.The printed PSCs with simplified device architecture and fabrication procedures could further enhance the competitive strength of PSC technology.In this work,we present an in-situ defect passivation(ISDP)assisted full-printing of high performance formamidine-lead bromide(FAPbBr_(3))PSCs.Only three rapid printing steps are involved for electron transporting layer(ETL),perovskite and carbon to form a complete solar cell on the low-cost fluorine-doped tin oxide(FTO)substrate.Long-chain polymer monomethyl ether polyethylene glycol is particularly utilized as the ISDP passivator,leading to conformal coating on the rough FTO and defect passivation for both ETL and perovskite during printing.A high efficiency of 10.85%(certified 10.14%)and a high V_(oc)up to 1.57 V are achieved for the printed device.The unencapsulated PSCs maintain above 90%of the initial efficiency after continuously heating at 85℃for 1000 h and over 80%of the efficiency after the maximum power point tracking for 3500 h.The fully printed semitransparent PSCs with carbon grids(CGs)show average visible light transmittance over 33%and an efficiency of 8.81%.
文摘Aim: Lead aprons are used to protect against scattered radiation from the patient during interventional procedures and certain special conventional radiological examinations. Given the importance of the role lead aprons are supposed to play in radiation protection, we propose to assess their conformity in medical imaging departments in public and religious hospitals in Togo. Materials and method: A multi-centre survey conducted from 26 November to 06 December 2021 in the radiology departments of public and religious health facilities in Togo. All aprons in use were included. The evaluation criteria were physical (visual), quantitative (radiographic) and qualitative (dosimetric). Results: We had registred 43 aprons among wich 27 (62.79%) leaded aprons were labelled non-compliant and 16 (37.21%) were labelled compliant. Of the aprons judged to be non-compliant, 70.37% were more than 10 years old and 96.30% showed defects on the radiographic images. The most common defects were vampire marks (18.64%), multiple folds (16.96%), cracks (16.96%), multiple cracks (15.25%), tears (8.47%), absence of lead (5.08%), holes (3.39%) and lead corrosion (1.69%). Defective aprons (62.96%) had at least two defects. The defects were of thoraco-abdomino-pelvic (74.07%), thoracic (14.82%) and abdomino-pelvic (11.11%) topography. For indirect exposure at 50 and 70 kilovolts, all the aprons had an attenuation factor greater than 90%. After dosimetric measurement, 13.95% of aprons had attenuation factors below 90% for indirect exposure at 100 kilovolts. Conclusion: The compliance of the leaded decks is trifactorial (physical, radiographic and dosimetric). However, there is no significant difference in X-ray attenuation capacity between defective and normal decks.
文摘Perforation of the right ventricle during placement of pacing wires is a welldocumented complication and can be potentially fatal.Use of temporary pacemaker,helical screw leads and steroids use prior to implant are recognised as risk factors for development of post-permanent pacemaker effusion.We reported an unusual case of pacing wire perforating interventricular septum into the left ventricle that occurred during the implant procedure performed in another institution.After the preoperative work-up and transfer to our tertiary cardiothoracic centre,the patient underwent successful surgical management.In conclusion,early recognition and timely diagnosis using advanced multimodality imaging can guide surgical intervention and prevent unfavourable consequences of device-related complications.
基金National Natural Science Foundation of China(42230603,42275020)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)+3 种基金Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(2020B1212060025)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021001)Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,MNR(QNHX2310)Future Earth Early-Career Fellowship of the Future Earth Global Secretariat Hub China。
文摘Drought events have become more frequent and intense over East Asia in recent decades,leading to huge socioeconomic impacts.Although the droughts have been studied extensively by cases or for individual regions,their leading variability and associated causes remain unclear.Based on the Standardized Precipitation Evapotranspiration Index(SPEI)and ERA5 reanalysis product from 1979 to 2020,this study evealuates the severity of spring droughts in East Asia and investigates their variations and associated drivers.The results indicate that North China and Mongolia have experienced remarkable trends toward dryness during spring in recent decades,while southwestern China has witnessed an opposite trend toward wetness.The first Empirical Orthogonal Function mode of SPEI variability reveals a similar seesawing pattern,with more severe dryness in northwestern China,Mongolia,North China,South Korea,and Japan but increased wetness in Southwestern China and southeast Asia.Further investigation reveals that the anomalously dry(wet)surface in North(Southwestern)China is significantly associated with anomalously high(low)temperature,less(more)precipitation,and reduced(increased)soil moisture during the previous winter and early spring,regulated by an anomalous anticyclone(cyclone)and thus reduced(increased)water vapor convergence.The spring dry-wet pattern in East Asia is also linked to cold sea surface temperature anomalies in the central-eastern Pacific.The findings of this study have important implications for improving the prediction of spring drought events in East Asia.
基金supported by the National Key Research and Development Program of China(No.2022YFC3700701)National Natural Science Foundation of China(Grant Nos.41775146,42061134009)+1 种基金USTC Research Funds of the Double First-Class Initiative(YD2080002007)Strategic Priority Research Program of Chinese Academy of Sciences(XDB41000000).
文摘Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well known.In this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are investigated.With increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal variations.In general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary particles.In spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural dust.In summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation rate.In autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.
基金Natural Science Foundation of Liaoning Province(2022-MS-305)Foundation of Liaoning Province Education Administration(LJKZ1108).
文摘The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on the Reynolds Averaged Navier-Stokes equations(RANS).The results indicate that when sand-induced holes and small pits are involved as leading edge wear features,they have a minimal influence on the lift and drag coefficients of the airfoil.However,if delamination occurs in the same airfoil region,it significantly impacts the lift and resistance characteristics of the airfoil.Specifically,as the angle of attack grows,there is a significant decrease in the lift coefficient accompanied by a sharp increase in the drag coefficient.As wear intensifies,these effects gradually increase.Moreover,the leading edge wear can exacerbate flow separation near the trailing edge suction surface of the airfoil and cause forward displacement of the separation point.
基金the support from the National Key R&D Program of China(No.2018YFC1901606).
文摘A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.
基金Supported by Party Building Research Project of Hubei University of Science and Technology(2022DJ-11).
文摘In accordance with the pattern of"great ideology and politics",the Party and youth League organizations assume the role of vanguard in the organization of colleges and universities.Simultaneously,they serve as a pivotal force in ideological and political education.In order to construct a comprehensive ideological and political framework encompassing the entire educational process,it is of paramount importance to identify an efficacious methodology for Party building leading League construction.This paper employs a comprehensive analysis to elucidate the pivotal role of Party building leading League construction in facilitating ideological and political education.It also illuminates the practical challenges encountered in the implementation of Party building leading League construction initiatives within colleges and universities.The article proposes a specific path for Party building leading League construction in colleges and universities based on three key aspects:cohesion of the consensus of Party building leading League building,establishment of the institutional system of Party building leading League construction,and creation of the model brand of Party building leading League construction.The aim is to promote in-depth development of Party building in colleges and universities and enhance the quality and effect of ideological and political education.
文摘This article analyzes the role of oxygen in lead zinc metallurgy,including shortening the metallurgical process,promoting energy conservation and environmental protection,improving metallurgical strength,enhancing raw material adaptability,and enhancing comprehensive recovery efficiency.This article introduces different lead zinc metallurgical processes and their oxygen consumption characteristics,including oxygen enriched side blowing lead smelting,oxygen bottom blowing lead smelting,oxygen enriched top blowing lead smelting,flash smelting lead,oxygen pressure leaching zinc smelting,and atmospheric pressure oxygen leaching zinc smelting.It is pointed out that oxygen enhanced metallurgy is the direction for the transformation and upgrading of lead zinc metallurgy.
文摘Although there are many lead-free soldering alloys on the market, none of them have ideal qualities. The researchers are combining binary alloys with a variety of additional materials to create the soldering alloys’ features. The eutectic Sn-9Zn alloy is among them. This paper investigated the mechanical and electrical properties of Sn-9Zn-x (Ag, Cu, Sb);{x = 0.2, 0.4, and 0.6} lead-free solder alloys. The mechanical properties such as elastic modulus, ultimate tensile strength (UTS), yield strength (YS), and ductility were examined at the strain rates in a range from 4.17 10−3 s−1 to 208.5 10−3 s−1 at room temperature. It is found that increasing the content of the alloying elements and strain rate increases the elastic modulus, ultimate tensile strength, and yield strength while the ductility decreases. The electrical conductivity of the alloys is found to be a little smaller than that of the Sn-9Zn eutectic alloy.
基金the financial support from the Taishan Scholar Project of Shandong Province (tsqn201812098)the National Natural Science Foundation of China (62275115)+5 种基金the Shandong Provincial Natural Science Foundation (ZR2020MF103)the Yantai City University Integration Development Project (2021XDRHXMXK26)the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciencesthe Natural Science Foundation of the Jiangsu Higher Education Institutions of China (22KJB510038)the Carbon Neutrality Innovation Research Center in Ludong UniversityLarge Instruments Open Foundation of Nantong University。
文摘The emergence of perovskite solar cells(PSCs) has greatly promoted the progress of photovoltaic technologies.The rapid development of PSCs has been driven by the advances in optimizing perovskite films and their adjacent interfaces.However,the polycrystalline perovskite layers in most highly efficient PSCs still contain various defects that greatly limit photovoltaic performance and stability of the devices.Herein,we introduce a multifunctional additive ethylene diamine tetra methylene phosphonic sodium(EDTMPS) with multiple anchor points into the precursor of perovskite to improve the efficiency and stability of PSCs and provide in-situ protection of lead leakage.The addition of EDTMPS acts as a crystal growth controller and passivation agent for perovskite films,thereby slowing down the crystallization rate of the film and obtaining high-quality perovskite films.Our study also provides an insight into how the modifier modulate the interfacial energy level arrangement as well as affect transfer of charge carriers and their recombination under photoinduced excitation.As a result,the power conversion efficiency(PCE) of single subcell with a working area of 0.255 cm^(2) increases significantly from 20.03% to 23.37%.Moreover,we obtained a PCE of 19.16% for the 25 cm^(2) module.Importantly,the unencapsulated EDTMP-modified PSCs exhibit better operational and thermal stability,as well as in-situ absorption of leaked lead ions.
基金financially supported by the National Key Research and Development Plan (2019YFE0107200)the National Natural Science Foundation of China (52072284)the Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHD2020-001)。
文摘Despite the high efficiency that has been achieved for the perovskite solar cells(PSCs),the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into the commercial market for a large-scale installation.Herein,we report a novel low-cost and biodegradable lead sequestration layer with high compatibility for up-scalable encapsulation of PSCs.Through a precisely designed cross-linking reaction of chemical agents,the as-made biodegradable chitosan composite film shows enhanced mechanical strength,chemical stability,and lead adsorption capacity.The designed encapsulation strategy reduces over 99.99% lead leakage to <2 ppb under varied simulations of weather conditions(hail,rain,or flood),which meet the safe level of drinking water set by the US Environmental Protection Agency(EPA).Moreover,the PSC efficiency is improved from 21.91% to22.82% due to the improved light absorption from the printed biodegradable lead absorption film.Finally,we present a prototype process of accumulation and recycling of lead compounds in PSCs derbies via the biodegradation process.Based on the low-cost biodegradable lead sequestration film,this environmental-friendly encapsulation strategy could address the lead leakage issue for further commercialization of PSCs.
文摘This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the penetrable data surface were used for noise prediction. The results showed that the three kinds of wave leading edge blades were effective in reducing the rotor-stator interaction tonal noise and also have a certain inhibitory effect on broadband noise. The A10W15 stator blade can effectively reduce broadband noise in the frequency range of 2200 - 4200 Hz. When the amplitude is increased to 20, the noise reduction effect is further enhanced. However, when the amplitude is increased to 30, the broadband noise reduction effect is no longer significant. Further research shows that the wave leading edge stator blades can significantly change the pressure fluctuation distribution on the leading edge and suction surface, which control the modal energy distribution. Finally, this paper analyzed multiple factors affecting the broadband noise reduction, such as the noise source cut-off and cut-on effect and correlation. The purpose of this paper is to explore the laws of the influence of wave leading edge blades on the duct noise of real fan, and to reveal its noise control mechanism. .
基金supported by the National Natural Science Foundation of China(Grant Nos.U2242206,41975094 and 41905062)the National Key Research and Development Program on monitoring,Early Warning and Prevention of Major Natural Disaster(Grant Nos.2017YFC1502302 and 2018YFC1506005)+1 种基金the Basic Research and Operational Special Project of CAMS(Grant No.2021Z007)the Met Office Climate Science for Service Partnership(CSSP)China.
文摘The dynamical prediction of the Asian-Australian monsoon(AAM)has been an important and long-standing issue in climate science.In this study,the predictability of the first two leading modes of the AAM is studied using retrospective prediction datasets from the seasonal forecasting models in four operational centers worldwide.Results show that the model predictability of the leading AAM modes is sensitive to how they are defined in different seasonal sequences,especially for the second mode.The first AAM mode,from various seasonal sequences,coincides with the El Niño phase transition in the eastern-central Pacific.The second mode,initialized from boreal summer and autumn,leads El Niño by about one year but can exist during the decay phase of El Niño when initialized from boreal winter and spring.Our findings hint that ENSO,as an early signal,is conducive to better performance of model predictions in capturing the spatiotemporal variations of the leading AAM modes.Still,the persistence barrier of ENSO in spring leads to poor forecasting skills of spatial features.The multimodel ensemble(MME)mean shows some advantage in capturing the spatiotemporal variations of the AAM modes but does not provide a significant improvement in predicting its temporal features compared to the best individual models in predicting its temporal features.The BCC_CSM1.1M shows promising skill in predicting the two AAM indices associated with two leading AAM modes.The predictability demonstrated in this study is potentially useful for AAM prediction in operational and climate services.
文摘Milk is one of the very important nutrients of human diet. The presence of toxic elements in milk may threaten the public health. This study reports the levels of Cadmium (Cd), Cobalt (Co) and Lead (Pb) in raw cow’s milk collected from different areas of Zanzibar Island during March - May 2016. The samples of raw milk were analyzed by Thermo Scientific-Atomic Absorption Spectrophotometer for quantitative determination of the metals in the matrix. The concentration of Co in this study ranged from ND at Mwanakwerekwe (MK1 and MK2) to a maximum of 0.004 mg/L at Mshelishelini (MS5) and Fuoni (F5) sites with mean concentration of 0.020 ± 0.003 mg/L for all sites. Concentration of Pb ranged between 0.05 - 0.51 mg/L at Fuoni (F7) and Mwanakwerekwe (MK1) respectively, with mean concentration of 0.263 ± 0.031 mg/L for all sites. However, Cd was only detected in one sample collected at Fuoni (F3) with a concentration of 0.001 mg/L. The results revealed that cow’s milk is contaminated with toxic metals, particularly Pb which exceeded the WHO maximum permissible level of 0.02 mg/L. The study furthermore sheds light on possible consequences to public health. It is recommended that, stakeholders especially in Zanzibar such as Zanzibar Food and Drug Authorities (ZFDA) and Zanzibar Bureau of Standards (ZBS) as well as researchers, use the findings of this study for policy making, future study plans, formulation of technical strategies to control milk contamination, risk assessment and develop new alternative methods to measure milk contamination even at a low detection limit for the sake of the consumers’ welfare before posing any serious effects to their health.