Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al...Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable.展开更多
Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically inves...Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.展开更多
This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al al...This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al alloy containing Fe impurity using a focused ion beam aided transmission electron microscope technique:(1^(-)011)[011^(-)1]_(Mg)//(011^(-))[011]_(Al_(2)Fe).Mg-3Al alloy was inoculated by adding 0.02wt%Fe to verify the nucleating potency of the Al_(2)Fe phase forα-Mg grain.The results indicated that Mg-3Al alloy was effectively refined with an average grain size declining from 1135 to 540μm.Among the potential Al-Fe phases of Mg-3Al-0.02Fe alloy,only the precipitation of the Al_(2)Fe phase occurs earlier than that ofα-Mg grain,and the Al_(2)Fe phase is stable in the nucleation stage ofα-Mg grain.Therefore,the Al_(2)Fe particle is the only available nucleating site for Mg-Al alloy with Fe impurity.The heterogeneous nucleation event ofα-Mg grain on the Al_(2)Fe particle is responsible for the grain refinement of Mg-3Al alloy inoculated by Fe.展开更多
Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, w...Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.展开更多
Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational...Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.展开更多
Overexpression of heat shock protein 27(HSP27)in gastric cancer is correlated with poor clinical prognosis.Melatonin,an endogenous hormone,shows promise in gastric cancer therapy.However,there is limited study on the ...Overexpression of heat shock protein 27(HSP27)in gastric cancer is correlated with poor clinical prognosis.Melatonin,an endogenous hormone,shows promise in gastric cancer therapy.However,there is limited study on the biological activity of HSP27 in response to melatonin treatment.In this study,we show an anti-proliferative action of melatonin on human gastric cancer cell lines BGC-823 and MGC-803.Biochemically,the inhibitory effect of melatonin is accompanied by the upregulation of HSP27 phosphorylation level.Transfection of gastric cancer cells with HSP27-specific siRNA effectively reduces HSP27 phosphorylation and potentiated melatonininduced inhibitory effect on cell proliferation.The reduction of cyclin D1 in melatonin-treated cells is also aggravated by HSP27 depletion.Moreover,melatonin stimulation increases p38 phosphorylation.Pretreatment with p38 inhibitor SB203580 not only remarkably suppresses melatonin-induced HSP27 phosphorylation,but also augment the inhibitory effect of melatonin on cyclin D1 expression as well as cell proliferation.Taken together,our study indicates the protective pathway of p38/HSP27 against melatonin-induced inhibitory effect on gastric cancer cell proliferation,suggesting that combined with p38/HSP27 pathway inhibitor,the therapeutic efficacy of melatonin on gastric cancer may be improved.展开更多
AIM： TO investigate the role of a-fetoprotein （AFP）, a cancer-associated fetal glycoprotein, in glucocorticoidinduced precocious maturation in rat colon. METHODS： Colons from suckling Sprague-Dawley rats were used...AIM： TO investigate the role of a-fetoprotein （AFP）, a cancer-associated fetal glycoprotein, in glucocorticoidinduced precocious maturation in rat colon. METHODS： Colons from suckling Sprague-Dawley rats were used in this study. Corticosterone acetate at a dose of 100 μg/g body weight was given to normal pups on days 7, 9 and 11 after birth to induce hypercorticoidism. Control animals were injected with identical volumes of normal saline. Some rats receiving corticosterone 7 d after birth were also treated with mifepristone （RU38486）, a glucocorticoid cytoplasm receptor antagonist to investigate the effects of glucocorticoids （GCs）. The morphological changes of the crypt depth and villous height of the villous zone in colon were observed as indicesof colon maturation. Expression levels of AFP in colons were detected by reverse transcriptase polymerase chain reaction and Western blotting. To identify the cellular lo- calization of AFP in developing rat colons, double-immu- nofluorescent staining was performed using antibodies to specific mesenchymal cell marker and AFP. RESULTS： Corticosterone increased the crypt depth and villous height in the colon of 8- and 10-d-old rats with hypercorticoidism compared with that in the control ani- mals （120% in 8-d-old rats and 118% in 10-d-old rats in villous height, P = 0.021; 145% in 8-d-old rats and 124% in 10-d-old rats in crypt depth, P = 0.017）. These increases were accompanied by an increase of AFP ex- pression in both mRNA and protein （2.5-folds in 8-d- old and 2.5-folds in 10-d-old rats higher than in control animals, P = 0.035; 1.8-folds in 8-d-old and 1.3-folds in 10-d-old rats higher than in control animals, P = 0.023）. Increased crypt depth and villous height and increased expression of AFP in the colon of rats with hypercorti- coidism were blocked by mifepristone. Both had positive staining for AFP or vimentin, and overlapped in mesen- chymal cells at each tested colon. CONCLUSION： GCs promote the development of rat colon. AFP appears to be involved, in part, in mediating the effects of GCs in the developmental colon.展开更多
Precipitation is an important component of global water and energy transport and a major aspect of climate change. Due to the scarcity of meteorological observations, the precipitation climate over Tibet has been insu...Precipitation is an important component of global water and energy transport and a major aspect of climate change. Due to the scarcity of meteorological observations, the precipitation climate over Tibet has been insufficiently documented. In this study, the distribution of precipitation during the rainy season over Tibet from 1980 to 2013 is described on monthly to annual time scales with meteorological observations. Furthermore, four precipitation products are compared to observations over Tibet. These datasets include products derived from the Asian Precipitation-Highly-Resolved Observational Data(APHRO), the Global Precipitation Climatology Centre(GPCC), the University of Delaware(UDel), and the China Meteorological Administration(CMA). The error, relative error, standard deviation, root-mean-square error, correlations and trends between these products for the same period are analyzed with in situ precipitation during the rainy season from May to September. The results indicate that these datasets can broadly capture the temporal and spatial precipitation distribution over Tibet. The precipitation gradually increases from northwest to southeast. The spatial precipitation in GPCC and CMA are similar and positively correlated to observations. Areas with the largest deviations are located in southwestern Tibet along the Himalayas. The APHRO product underestimates, while the UDel, GPCC, and CMA datasets overestimates precipitation on the basis of monthly and inter-annual variation. The biases in GPCC and CMA are smaller than those in APHRO and UDel with a mean relative error lower than 10% during the same periods. The linear trend of precipitation indicates that the increase in precipitation has accelerated extensively during the last 30 years in most regions of Tibet. The CMA generally achieves the best performance of these four precipitation products. Data uncertainty in Tibet might be caused by the low density of stations, complex topography between the grid points and stations, and the interpolation methods, which can also produce an obvious difference between the gridded data and observations.展开更多
In combination with the data of loss-making listed companies in manufacturing industry at capital market in 2008-2010,this paper analyzed the characteristics of loss of listed companies.Major reasons include the blind...In combination with the data of loss-making listed companies in manufacturing industry at capital market in 2008-2010,this paper analyzed the characteristics of loss of listed companies.Major reasons include the blind investment of management personnel,low operation and management level,blind pursuit of diversified operation,improper stock right structure,weak supervision of government,and imperfect delisting system.Finally,it came up with some countermeasures,including improving quality of management personnel,management personnel selecting proper investment projects,strengthening internal management of enterprise,implementing effective asset rearrangement,setting up effective incentive and restrictive mechanism,bringing into play regulation function of banks,improving delisting mechanism,reducing centralization of state owned stock right,and establishing and improving market information disclosure system.展开更多
Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a b...Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a binary nanophotocatalyst fabricated by blending two polymers,PS-PEG5(PS)and PBT-PEG5(PBT),with matched absorption and emission spectra,enabling a Forster resonance energy transfer(FRET)process for enhanced photocatalysis.These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation(FNP)technique with precious kinetic control over binary nanoparticle formation.The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g^(-1) h^(-1),2.5 times higher than that single component nanoparticles.Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles,which prolongs the excited-state lifetime and extends the namely“effective exciton diffusion length”.Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.展开更多
The quality of wrought magnesium(Mg)alloys is closely linked to the quality of the cast ingots.Conventionally casting(CC)Mg-2Y ingots exhibit relatively coarse grain sizes.When CC ingots undergo rolling processing(CC-...The quality of wrought magnesium(Mg)alloys is closely linked to the quality of the cast ingots.Conventionally casting(CC)Mg-2Y ingots exhibit relatively coarse grain sizes.When CC ingots undergo rolling processing(CC-10-R),the resulting Mg-2Y sheets retain coarse grain sizes(~11.87μm),while precipitating a small number of Mg_(24)Y_(5) nanoparticles(~0.26%),as well as forming a strong C-type texture(~10.91).The implementation of controlled diffusion solidification(CDS)effectively refines the grain size of Mg-2Y ingots and increases the content of Mg_(24)Y_(5) particles.When CDS is combined with rolling(CDS-10-R),the grain size is refined to~5.57μm,the precipitation of Mg_(24)Y_(5) nanoparticles is increased to~1.79%,and the C-type texture was weakened to~7.74.The CDS-10-R shows an increase in strength of~51.8% and an enhancement in plasticity of~32.6% compared to CC-10-R.The enhancement in strength is primarily due to fine-grain strengthening(~42.1% contributions)and precipitating strengthening(~39.6% contributions).The improvement in plasticity is attributed to the weakening of the{0001}basal texture,which facilitates the activation of<c+a>slips.Compared to other wrought Mg-Y alloys,Mg-2Y sheets produced by combining CDS with rolling possess exceptional strength-plasticity combinations.This finding presents a novel route to achieving high strength and plasticity in low-alloyed rare-earth Mg alloys.展开更多
Objective:Patients with homologous recombination deficiency(HRD)demonstrate distinct clinicopathological and prognostic features.However,standardised and clinically validated HRD detection methodologies specifically t...Objective:Patients with homologous recombination deficiency(HRD)demonstrate distinct clinicopathological and prognostic features.However,standardised and clinically validated HRD detection methodologies specifically tailored for non-small cell lung cancer(NSCLC)have yet to be established.Further research is needed to clarify the precise role and clinical implications of HRD in NSCLC.Methods:A cohort of 580 treatment-naive NSCLC patients was retrospectively enrolled.Comprehensive genomic profiling(CGP)was performed for all patients,and HRD status was evaluated using two genomic scar score(GSS)-based algorithms:a machine learning-based GSS(ML-GSS)and a continuous linear regression-based GSS(CLR-GSS).To assess the diagnostic performance(sensitivity and specificity)of the ML-GSS and CLR-GSS algorithms for HRD detection,immunohistochemical(IHC)staining was conducted for two HRD-related biomarkers:Schlafen 11(SLFN11)and RAD51.Survival analysis,including progression-free survival(PFS),along with multivariable Cox proportional hazards models,was performed to compare the prognostic value of the two HRD algorithms.Results:Among all patients,146(25.2%)and 46(7.9%)were classified as HRD-positive(HRD+)by ML-GSS and CLR-GSS,respectively.Using SLFN11 IHC expression as the reference standard,comparative analysis demonstrated that ML-GSS exhibited significantly higher sensitivity but lower specificity than CLR-GSS.This trend was consistently observed in RAD51 staining analysis.Compared to HRD-negative(HRD-)patients,MLGSS-defined HRD+cases displayed distinct clinicopathological and genomic features,including a higher prevalence of homologous recombination(HR)-related genes mutations,BRCA1/2 mutations,TP53 mutations,elevated tumor mutation burden(TMB),and increased copy number variations(CNVs).In contrast,CLR-GSSdefined HRD+patients were only enriched for BRCA1/2 mutations,TP53 mutations,and elevated TMB.Furthermore,ML-GSS-defined HRD+status was associated with significantly worse prognosis following first-line therapy compared to HRD-patients.Univariate and multivariable Cox analyses identified ML-GSS-defined HRD+and TP53 mutations as significant predictors and independent risk factors,respectively.No such associations were observed in the CLR-GSS-defined HRD+cohort.Conclusions:ML-GSS demonstrated superior performance to CLR-GSS in assessing chromosomal instability(CIN)and showed greater clinical utility.We recommend the ML-GSS algorithm as a robust and clinically validated tool for HRD/CIN evaluation in NSCLC.Furthermore,ML-GSS-defined HRD+status was identified as both a significant predictor and an independent risk factor.展开更多
Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During...Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.展开更多
Genistein is effective against amyloid-β toxicity, but the underlying mechanisms are unclear. We hypothesized that genistein may protect neurons by inhibiting the mitochondrial apoptotic pathway, and thereby play a r...Genistein is effective against amyloid-β toxicity, but the underlying mechanisms are unclear. We hypothesized that genistein may protect neurons by inhibiting the mitochondrial apoptotic pathway, and thereby play a role in the prevention of Alzheimer＇s disease. A rat model of Alzheimer＇s disease was established by intraperitoneal injection of D-galactose and intracerebral injection of amyloid-β peptide （25-35）. In the genistein treatment groups, a 7-day pretreatment with genistein （10, 30, 90 mg/kg） was given prior to establishing Alzheimer＇s disease model, for 49 consecutive days. Terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay demonstrated a reduction in apoptosis in the hippocampus of rats treated with genistein. Western blot analysis showed that expression levels of capase-3, Bax and cytochrome c were decreased compared with the model group. Furthermore, immunohistochemical staining revealed reductions in cytochrome c and Bax immunoreactivity in these rats. Morris water maze revealed a substantial shortening of escape latency by genistein in Alzheimer＇s disease rats. These findings suggest that genistein decreases neuronal loss in the hippocampus, and improves learning and memory ability. The neuroprotective effects of genistein are associated with the inhibition of the mitochondrial apoptotic pathway, as shown by its ability to reduce levels of caspase-3, Bax and cytochrome c.展开更多
Total dissolved gas supersaturation(TDGS) appears when the pressures of gases in a solution exceed the barometric pressures.TDGS is often caused by flood discharge at dams.It may lead to gas bubble disease(GBD) for fi...Total dissolved gas supersaturation(TDGS) appears when the pressures of gases in a solution exceed the barometric pressures.TDGS is often caused by flood discharge at dams.It may lead to gas bubble disease(GBD) for fish and biochemical responses of selected fish and other aquatic organisms.The purpose of this study was to determine the impact of long-term TDGS levels on the growth and biochemical responses of rock carp(Procypris rabaudi Tchang) dwelling in the upper reaches of the Yangtze River.Three-year-old rock carp were exposed to TDGS levels at 100%,104%,108%,112%,and 116% for 42 d.Samples were taken every 7 d after the start of the trial in order to determine catalase(CAT) and superoxide dismutase(SOD) activities in gill and muscle tissues.Samples were taken at Days 0 and 42 of exposure to determine growth rate.Little effect was found on growth rate in all treatment groups.SOD and CAT activities varied in different tissues,according to time of exposure and TDGS levels.The biochemical response of fish exposed to TDGS was more obvious in gill tissue than in muscle tissue.Surveys of SOD and CAT activities in different tissues offer important information about the effect of TDGS on the rare fish in the Yangtze River,and may help evaluate the risk to the aquatic eco-environment and aquatic ecosystem in the downstream of the Yangtze River.展开更多
Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were expose...Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).展开更多
基金Project(2013B090500091)supported by Industry-University-Research Combined Project of Guangdong Province,ChinaProject(20180358)supported by the Shenzhen Jiansheng Technology Inc.Cooperation Project,China。
文摘Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable.
基金financially supported by the National Natural Science Foundation of China(No.52174363)the GDAS Project of Science and Technology Development,China(No.2019GDASYL-0203002)+2 种基金the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)the Science and Technology Project of Zhaoqing City,China(Nos.2021C003,2018K006)the Development of Key Technologies for Material and Microstructure Control of High Thermal Conductivity Casting Aluminum Alloy,China(No.2014A030313221)。
文摘Ce element was introduced to modify Al−2%Fe(mass fraction)binary alloy.The microstructures,crystallization behavior,electrical/thermal conductivities and mechanical properties of these alloys were systematically investigated.The results indicated that the appropriate Ce addition decreased the recalescence temperature and growth temperature of Al−Fe eutectic structure,improved the morphology and distribution of Fe-containing phase,and simultaneously increased the conductivity and mechanical properties.The annealed treatment improved the thermal conductivity of these alloys due to the decreasing concentration of point defects.Rolling process further broke up the coarser Fe-containing phases into finer particles and made the secondary phases uniformly distributed in theα(Al)matrix.After subsequent annealing treatment and rolling deformation,the thermal conductivity,ultimate tensile strength and hardness of the Al−2%Fe−0.3%Ce(mass fraction)alloy reached 226 W/(m·K),(182±1.4)MPa and HBW(49.5±1.7),respectively.
基金financially supported by the National Natural Science Foundation of China(No.51871100)。
文摘This study revealed the nucleation event and grain refinement mechanism of Mg-Al alloy induced by Fe impurity.The following orientation relationship was observed between Al-Fe particle andα-Mg matrix in the Mg-3Al alloy containing Fe impurity using a focused ion beam aided transmission electron microscope technique:(1^(-)011)[011^(-)1]_(Mg)//(011^(-))[011]_(Al_(2)Fe).Mg-3Al alloy was inoculated by adding 0.02wt%Fe to verify the nucleating potency of the Al_(2)Fe phase forα-Mg grain.The results indicated that Mg-3Al alloy was effectively refined with an average grain size declining from 1135 to 540μm.Among the potential Al-Fe phases of Mg-3Al-0.02Fe alloy,only the precipitation of the Al_(2)Fe phase occurs earlier than that ofα-Mg grain,and the Al_(2)Fe phase is stable in the nucleation stage ofα-Mg grain.Therefore,the Al_(2)Fe particle is the only available nucleating site for Mg-Al alloy with Fe impurity.The heterogeneous nucleation event ofα-Mg grain on the Al_(2)Fe particle is responsible for the grain refinement of Mg-3Al alloy inoculated by Fe.
基金supported by grants from the National Natural Science Foundation of China (No. 30872926)the Program for AdvancedTalents within Six Industries of Jiangsu Province (08-D) to Dr. Luo Gu+1 种基金the Science Development Foundation of Nanjing Medical University (No. 2010NJMUZ35)the Research Program funded by Schoolof Basic Medical Science, Nanjing Medical University to Dr. Jun Du
文摘Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.
基金This work was jointly supported by the National Natural Science Foundation of China(Grant Nos.41975137,42175012,and 41475097)the National Key Research and Development Program(Grant No.2018YFF0300103).
文摘Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems.
基金supported by the Training Programs of Innovation and Entrepreneurship for Undergraduates by Jiangsu Province(201810312018Z)to Jun Du,Chenchen Zhu,Kaiquan Lithe Training Programs of Innovation and Entrepreneurship for Undergraduates by Nanjing Medical University to Jun Du,Yuting Wang
文摘Overexpression of heat shock protein 27(HSP27)in gastric cancer is correlated with poor clinical prognosis.Melatonin,an endogenous hormone,shows promise in gastric cancer therapy.However,there is limited study on the biological activity of HSP27 in response to melatonin treatment.In this study,we show an anti-proliferative action of melatonin on human gastric cancer cell lines BGC-823 and MGC-803.Biochemically,the inhibitory effect of melatonin is accompanied by the upregulation of HSP27 phosphorylation level.Transfection of gastric cancer cells with HSP27-specific siRNA effectively reduces HSP27 phosphorylation and potentiated melatonininduced inhibitory effect on cell proliferation.The reduction of cyclin D1 in melatonin-treated cells is also aggravated by HSP27 depletion.Moreover,melatonin stimulation increases p38 phosphorylation.Pretreatment with p38 inhibitor SB203580 not only remarkably suppresses melatonin-induced HSP27 phosphorylation,but also augment the inhibitory effect of melatonin on cyclin D1 expression as well as cell proliferation.Taken together,our study indicates the protective pathway of p38/HSP27 against melatonin-induced inhibitory effect on gastric cancer cell proliferation,suggesting that combined with p38/HSP27 pathway inhibitor,the therapeutic efficacy of melatonin on gastric cancer may be improved.
文摘AIM： TO investigate the role of a-fetoprotein （AFP）, a cancer-associated fetal glycoprotein, in glucocorticoidinduced precocious maturation in rat colon. METHODS： Colons from suckling Sprague-Dawley rats were used in this study. Corticosterone acetate at a dose of 100 μg/g body weight was given to normal pups on days 7, 9 and 11 after birth to induce hypercorticoidism. Control animals were injected with identical volumes of normal saline. Some rats receiving corticosterone 7 d after birth were also treated with mifepristone （RU38486）, a glucocorticoid cytoplasm receptor antagonist to investigate the effects of glucocorticoids （GCs）. The morphological changes of the crypt depth and villous height of the villous zone in colon were observed as indicesof colon maturation. Expression levels of AFP in colons were detected by reverse transcriptase polymerase chain reaction and Western blotting. To identify the cellular lo- calization of AFP in developing rat colons, double-immu- nofluorescent staining was performed using antibodies to specific mesenchymal cell marker and AFP. RESULTS： Corticosterone increased the crypt depth and villous height in the colon of 8- and 10-d-old rats with hypercorticoidism compared with that in the control ani- mals （120% in 8-d-old rats and 118% in 10-d-old rats in villous height, P = 0.021; 145% in 8-d-old rats and 124% in 10-d-old rats in crypt depth, P = 0.017）. These increases were accompanied by an increase of AFP ex- pression in both mRNA and protein （2.5-folds in 8-d- old and 2.5-folds in 10-d-old rats higher than in control animals, P = 0.035; 1.8-folds in 8-d-old and 1.3-folds in 10-d-old rats higher than in control animals, P = 0.023）. Increased crypt depth and villous height and increased expression of AFP in the colon of rats with hypercorti- coidism were blocked by mifepristone. Both had positive staining for AFP or vimentin, and overlapped in mesen- chymal cells at each tested colon. CONCLUSION： GCs promote the development of rat colon. AFP appears to be involved, in part, in mediating the effects of GCs in the developmental colon.
基金supported by the National Natural Science Foundation of China (Grant No. 41130960)Key Science and Technology Plan of Tibet Autonomous Region (Grant No. XZ201703-GA-01)
文摘Precipitation is an important component of global water and energy transport and a major aspect of climate change. Due to the scarcity of meteorological observations, the precipitation climate over Tibet has been insufficiently documented. In this study, the distribution of precipitation during the rainy season over Tibet from 1980 to 2013 is described on monthly to annual time scales with meteorological observations. Furthermore, four precipitation products are compared to observations over Tibet. These datasets include products derived from the Asian Precipitation-Highly-Resolved Observational Data(APHRO), the Global Precipitation Climatology Centre(GPCC), the University of Delaware(UDel), and the China Meteorological Administration(CMA). The error, relative error, standard deviation, root-mean-square error, correlations and trends between these products for the same period are analyzed with in situ precipitation during the rainy season from May to September. The results indicate that these datasets can broadly capture the temporal and spatial precipitation distribution over Tibet. The precipitation gradually increases from northwest to southeast. The spatial precipitation in GPCC and CMA are similar and positively correlated to observations. Areas with the largest deviations are located in southwestern Tibet along the Himalayas. The APHRO product underestimates, while the UDel, GPCC, and CMA datasets overestimates precipitation on the basis of monthly and inter-annual variation. The biases in GPCC and CMA are smaller than those in APHRO and UDel with a mean relative error lower than 10% during the same periods. The linear trend of precipitation indicates that the increase in precipitation has accelerated extensively during the last 30 years in most regions of Tibet. The CMA generally achieves the best performance of these four precipitation products. Data uncertainty in Tibet might be caused by the low density of stations, complex topography between the grid points and stations, and the interpolation methods, which can also produce an obvious difference between the gridded data and observations.
基金China National Social Science Fund Project(13CGL050)Hu-manities and Social Science Research Youth Project of the Ministry of Educa-tion(13YJC630027,11YJC630243,12YJC630010)Basic Research Fund of Central Universities(SWU1309116,SWU1309202)
文摘In combination with the data of loss-making listed companies in manufacturing industry at capital market in 2008-2010,this paper analyzed the characteristics of loss of listed companies.Major reasons include the blind investment of management personnel,low operation and management level,blind pursuit of diversified operation,improper stock right structure,weak supervision of government,and imperfect delisting system.Finally,it came up with some countermeasures,including improving quality of management personnel,management personnel selecting proper investment projects,strengthening internal management of enterprise,implementing effective asset rearrangement,setting up effective incentive and restrictive mechanism,bringing into play regulation function of banks,improving delisting mechanism,reducing centralization of state owned stock right,and establishing and improving market information disclosure system.
基金supported by National Natural Science Foundation of China(NSFC,22338006,92356301,9235630033 and 22375062)Shanghai Municipal Science and Technology Major Project(21JC1401700)+4 种基金Shanghai Pilot Program for Basic Research(22TQ1400100-10)Fundamental Research Funds for the Central UniversitiesShanghai Pujiang Program(22PJ1402400)“Chenguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22CGA32)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001).
文摘Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a binary nanophotocatalyst fabricated by blending two polymers,PS-PEG5(PS)and PBT-PEG5(PBT),with matched absorption and emission spectra,enabling a Forster resonance energy transfer(FRET)process for enhanced photocatalysis.These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation(FNP)technique with precious kinetic control over binary nanoparticle formation.The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g^(-1) h^(-1),2.5 times higher than that single component nanoparticles.Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles,which prolongs the excited-state lifetime and extends the namely“effective exciton diffusion length”.Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.
基金supported by the National Natural Science Foundation of China(No.52474437).
文摘The quality of wrought magnesium(Mg)alloys is closely linked to the quality of the cast ingots.Conventionally casting(CC)Mg-2Y ingots exhibit relatively coarse grain sizes.When CC ingots undergo rolling processing(CC-10-R),the resulting Mg-2Y sheets retain coarse grain sizes(~11.87μm),while precipitating a small number of Mg_(24)Y_(5) nanoparticles(~0.26%),as well as forming a strong C-type texture(~10.91).The implementation of controlled diffusion solidification(CDS)effectively refines the grain size of Mg-2Y ingots and increases the content of Mg_(24)Y_(5) particles.When CDS is combined with rolling(CDS-10-R),the grain size is refined to~5.57μm,the precipitation of Mg_(24)Y_(5) nanoparticles is increased to~1.79%,and the C-type texture was weakened to~7.74.The CDS-10-R shows an increase in strength of~51.8% and an enhancement in plasticity of~32.6% compared to CC-10-R.The enhancement in strength is primarily due to fine-grain strengthening(~42.1% contributions)and precipitating strengthening(~39.6% contributions).The improvement in plasticity is attributed to the weakening of the{0001}basal texture,which facilitates the activation of<c+a>slips.Compared to other wrought Mg-Y alloys,Mg-2Y sheets produced by combining CDS with rolling possess exceptional strength-plasticity combinations.This finding presents a novel route to achieving high strength and plasticity in low-alloyed rare-earth Mg alloys.
基金supported by the National High Level Hospital Clinical Research Funding(No.BJ-2019-195)the National High Level Hospital Clinical Research Funding(No.BJ-2023-090)。
文摘Objective:Patients with homologous recombination deficiency(HRD)demonstrate distinct clinicopathological and prognostic features.However,standardised and clinically validated HRD detection methodologies specifically tailored for non-small cell lung cancer(NSCLC)have yet to be established.Further research is needed to clarify the precise role and clinical implications of HRD in NSCLC.Methods:A cohort of 580 treatment-naive NSCLC patients was retrospectively enrolled.Comprehensive genomic profiling(CGP)was performed for all patients,and HRD status was evaluated using two genomic scar score(GSS)-based algorithms:a machine learning-based GSS(ML-GSS)and a continuous linear regression-based GSS(CLR-GSS).To assess the diagnostic performance(sensitivity and specificity)of the ML-GSS and CLR-GSS algorithms for HRD detection,immunohistochemical(IHC)staining was conducted for two HRD-related biomarkers:Schlafen 11(SLFN11)and RAD51.Survival analysis,including progression-free survival(PFS),along with multivariable Cox proportional hazards models,was performed to compare the prognostic value of the two HRD algorithms.Results:Among all patients,146(25.2%)and 46(7.9%)were classified as HRD-positive(HRD+)by ML-GSS and CLR-GSS,respectively.Using SLFN11 IHC expression as the reference standard,comparative analysis demonstrated that ML-GSS exhibited significantly higher sensitivity but lower specificity than CLR-GSS.This trend was consistently observed in RAD51 staining analysis.Compared to HRD-negative(HRD-)patients,MLGSS-defined HRD+cases displayed distinct clinicopathological and genomic features,including a higher prevalence of homologous recombination(HR)-related genes mutations,BRCA1/2 mutations,TP53 mutations,elevated tumor mutation burden(TMB),and increased copy number variations(CNVs).In contrast,CLR-GSSdefined HRD+patients were only enriched for BRCA1/2 mutations,TP53 mutations,and elevated TMB.Furthermore,ML-GSS-defined HRD+status was associated with significantly worse prognosis following first-line therapy compared to HRD-patients.Univariate and multivariable Cox analyses identified ML-GSS-defined HRD+and TP53 mutations as significant predictors and independent risk factors,respectively.No such associations were observed in the CLR-GSS-defined HRD+cohort.Conclusions:ML-GSS demonstrated superior performance to CLR-GSS in assessing chromosomal instability(CIN)and showed greater clinical utility.We recommend the ML-GSS algorithm as a robust and clinically validated tool for HRD/CIN evaluation in NSCLC.Furthermore,ML-GSS-defined HRD+status was identified as both a significant predictor and an independent risk factor.
基金supported by the National Natural Science Foundation of China(Nos.51871100 and 12074126).
文摘Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.
基金supported by the National Natural Science Foundation of China,No.81202941the Key Project Foundation of Oversea Visiting and Research for the Excellent Young and Middle-aged Faculties in Universities of Anhui Province in China,No.gxfx ZD2016119the Key Project Foundation of Natural Science Research in Universities of Anhui Province in China,No.KJ2016A406
文摘Genistein is effective against amyloid-β toxicity, but the underlying mechanisms are unclear. We hypothesized that genistein may protect neurons by inhibiting the mitochondrial apoptotic pathway, and thereby play a role in the prevention of Alzheimer＇s disease. A rat model of Alzheimer＇s disease was established by intraperitoneal injection of D-galactose and intracerebral injection of amyloid-β peptide （25-35）. In the genistein treatment groups, a 7-day pretreatment with genistein （10, 30, 90 mg/kg） was given prior to establishing Alzheimer＇s disease model, for 49 consecutive days. Terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay demonstrated a reduction in apoptosis in the hippocampus of rats treated with genistein. Western blot analysis showed that expression levels of capase-3, Bax and cytochrome c were decreased compared with the model group. Furthermore, immunohistochemical staining revealed reductions in cytochrome c and Bax immunoreactivity in these rats. Morris water maze revealed a substantial shortening of escape latency by genistein in Alzheimer＇s disease rats. These findings suggest that genistein decreases neuronal loss in the hippocampus, and improves learning and memory ability. The neuroprotective effects of genistein are associated with the inhibition of the mitochondrial apoptotic pathway, as shown by its ability to reduce levels of caspase-3, Bax and cytochrome c.
基金Project (No. 50979063) supported by the National Natural Science Foundation of China
文摘Total dissolved gas supersaturation(TDGS) appears when the pressures of gases in a solution exceed the barometric pressures.TDGS is often caused by flood discharge at dams.It may lead to gas bubble disease(GBD) for fish and biochemical responses of selected fish and other aquatic organisms.The purpose of this study was to determine the impact of long-term TDGS levels on the growth and biochemical responses of rock carp(Procypris rabaudi Tchang) dwelling in the upper reaches of the Yangtze River.Three-year-old rock carp were exposed to TDGS levels at 100%,104%,108%,112%,and 116% for 42 d.Samples were taken every 7 d after the start of the trial in order to determine catalase(CAT) and superoxide dismutase(SOD) activities in gill and muscle tissues.Samples were taken at Days 0 and 42 of exposure to determine growth rate.Little effect was found on growth rate in all treatment groups.SOD and CAT activities varied in different tissues,according to time of exposure and TDGS levels.The biochemical response of fish exposed to TDGS was more obvious in gill tissue than in muscle tissue.Surveys of SOD and CAT activities in different tissues offer important information about the effect of TDGS on the rare fish in the Yangtze River,and may help evaluate the risk to the aquatic eco-environment and aquatic ecosystem in the downstream of the Yangtze River.
基金Project supported by the National Natural Science Foundation ofChina (No. 50979063)the Scientific Research Foundation for Young Teachers of Xihua University (No. Z1120412),China
文摘Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).
