Cropland productivity has been significantly impacted by soil acidification resulted from nitrogen （N） fertilization, especially as a result of excess ammoniacal N input. With decades＇ intensive agricultural cultiv...Cropland productivity has been significantly impacted by soil acidification resulted from nitrogen （N） fertilization, especially as a result of excess ammoniacal N input. With decades＇ intensive agricultural cultivation and heavy chemical N input in the Huang-Huai-Hai Plain, the impact extent of induced proton input on soil pH in the long term was not yet clear. In this study, acidification rates of different soil layers in the soil profile （0-120 cm） were calculated by pH buffer capacity （pHBC） and net input of protons due to chemical N incorporation. Topsoil （0-20 cm） pH changes of a long-term fertilization field （from 1989） were determined to validate the predicted values. The results showed that the acid and alkali buffer capacities varied significantly in the soil profile, averaged 692 and 39.8 mmolc kg-1 pH-1, respectively. A significant （P〈0.05） correlation was found between pHRC and the content of calcium carbonate. Based on the commonly used application rate of urea （500 kg N ha-1 yr-1）, the induced proton input in this region was predicted to be 16.1 kmol ha-1 yr-1, and nitrification and plant uptake of nitrate were the most important mechanisms for proton producing and consuming, respectively. The acidification rate of topsoil （0-20 cm） was estimated to be 0.01 unit pH yr-1 at the assumed N fertilization level. From 1989 to 2009, topsoil pH （0-20 cm） of the long-term fertilization field decreased from 8.65 to 8.50 for the PK （phosphorus, 150 kg P205 ha-1 yr-1; potassium, 300 kg K20 ha-1 yr-1; without N fertilization）, and 8.30 for NPK （nitrogen, 300 kg N ha-1 yr-1; phosphorus, 150 kg P2Os ha-1 yr-1; potassium, 300 kg K20 ha -1 yr-1）, respectively. Therefore, the apparent soil acidification rate induced by N fertilization equaled to 0.01 unit pH yr-1, which can be a reference to the estimated result, considering the effect of atmospheric N deposition, crop biomass, field management and plant uptake of other nutrients and cations. As protons could be consum展开更多
The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structu...The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests： the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength.展开更多
Background:The downstaging of hepatocellular carcinoma(HCC)has been confirmed to benefit liver transplantation(LT)patients whose tumors are beyond the transplantation criteria.Milan criteria(MC),a tumor size and numbe...Background:The downstaging of hepatocellular carcinoma(HCC)has been confirmed to benefit liver transplantation(LT)patients whose tumors are beyond the transplantation criteria.Milan criteria(MC),a tumor size and number-based assessment,is currently used as the endpoint in these patients.However,many studies believe that tumor biological behavior should be added to the evaluation criteria for downstaging efficacy.Hence,this study aimed to explore the feasibility of Hangzhou criteria(HC),which introduced tumor grading and alpha-fetoprotein in addition to tumor size and number,as an endpoint of downstaging.Methods:We performed a multicenter and retrospective study of 206 patients accepted locoregional therapy(LRT)as downstaging/bridge treatment prior to LT in three centers of China.Results:Recipients were divided into four groups:failed downstaging to the HC(group A,n=46),successful downstaging to the HC(group B,n=30),remained within the HC all the time(group C,n=113),and tumor progressed(group D,n=17).The 3-year HCC recurrence probabilities of groups B and C were not significantly different(10.3%vs.11.6%,P=0.87).The HCC recurrent rate was significantly higher in group A(52.3%)compared with that in group B/C(P<0.05).Seven patients(7/76,9.2%)whose tumor exceeded the the HC were successfully downstaged to the MC,and 39.5%(30/76)to the the HC.In group B,23 patients remained beyond the MC and their survivals were as well as those of patients within the MC.Conclusions:Compared to the MC,HC downstaging criteria can give more HCC patients access to LT and furthermore,the outcome of these patients is the same as those matching MC downstaging criteria.Hangzhou downstaging criteria therefore is applicable in clinical practice.展开更多
AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by...AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by lipid-mediated transfection, including transient and stable transfection. Positive clones were screened by incubating in the selective medium with 600 μg/mL G418 and named HL-7702/HBV-encoded X protein （HBx） cells. The expressions of Fas/FasL, Bax/Bcl-2, and c-myc mRNA were measured by semi-quantitative RT-PCR in HL-7702/HBx and control group, respectively.RESULTS： RT-PCR analysis confirmed that HBV X gene was transfected into HL-7702 cells successfully. By semiquantitative RT-PCR analysis, Bax and c-myc mRNA levels in HL-7702/HBx cells of transient transfection were significantly higher than those in control, FasL and c-myc mRNA levels in HL-7702/HBx cells of stable transfection were significantly higher than those in control, whereas the Bcl-2 mRNA levels in HL-7702/HBx cells of transient and stable transfection were significantly lower than thosein control.CONCLUSION： HBV X gene may promote the apoptosis of hepatocytes by regulating the expressions of Fas/FasL, Bax/Bcl-2, and c-myc gene in a dose-dependent manner.展开更多
Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson’s disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment...Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson’s disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment of a variety of diseases. However, whether they can protect neurons in Parkinson’s disease by inhibiting microglia-mediated inflammatory responses is not yet known. In this study, exosomes were isolated from human umbilical cord mesenchymal stem cells and injected into a 6-hydroxydopamine-induced rat model of Parkinson’s disease. We found that the exosomes injected through the tail vein and lateral ventricle were absorbed by dopaminergic neurons and microglia on the affected side of the brain, where they repaired nigral-striatal dopamine system damage and inhibited microglial activation. Furthermore, in an in vitro cell model, pretreating lipopolysaccharide-stimulated BV2 cells with exosomes reduced interleukin-1β and interleukin-18 secretion, prevented the adoption of pyroptosis-associated morphology by BV2 cells, and increased the survival rate of SH-SY5Y cells. Potential targets for treatment with human umbilical cord mesenchymal stem cells and exosomes were further identified by high-throughput microRNA sequencing and protein spectrum sequencing. Our findings suggest that human umbilical cord mesenchymal stem cells and exosomes are a potential treatment for Parkinson’s disease, and that their neuroprotective effects may be mediated by inhibition of excessive microglial proliferation.展开更多
AIM： To investigate the effect of hepatitis B virus （HBV） X gene on apoptosis and expressions of apoptosis factors in X gene-transfected HepG2 cells.METHODS： The HBV X gene eukaryon expression vector pcDNA3-X was ...AIM： To investigate the effect of hepatitis B virus （HBV） X gene on apoptosis and expressions of apoptosis factors in X gene-transfected HepG2 cells.METHODS： The HBV X gene eukaryon expression vector pcDNA3-X was transiently transfected into HepG2 cells by lipid-media transfection. Untransfected HepG2 and HepG2 transfected with pcDNA3 were used as controls. Expression of HBx in HepG2 was identified by RT-PCR. MTT and TUNEL were employed to measure proliferation and apoptosis of cells in.three groups. Semi-quantified RT-PCR was used to evaluate the expression levels of Fas/FasL, Bax/Bcl-xL, and c-myc in each group.RESULTS： HBV X gene was transfected into HepG2 cells successfully. RT-PCR showed that HBx was only expressed in HepG2/pcDNA3-X cells, but not expressed in HepG2 and HepG2/pcDNA3 cells. Analyzed by MTT, cell proliferationcapacity was obviously lower in HepG2/pcDNA3-X cells （0.08910±0.003164） than in HepG2 （0.14410±0.004927） and HepG2/pcDNA3 cells （0.12150±0.007159） （P〈0.05 and P〈0.01）. Analyzed by TUNEL, cell apoptosis was much more in HepG2/pcDNA3-X cells （980/2 000） than HepG2 （420/2 000）, HepG2/pcDNA3 cells （520/2 000） （P〈0.05 and P〈0.01）. Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasL was significantly higher in HepG2 cells transfected with HBx than in HepG2 and HepG2/pcDNA3 cells （P〈0.05 and P〈0.01）. Bax/Bcl-xL expression level was also elevated in HepG2/pcDNA3-X cells （P〈0.05 and P〈0.01）. Expression of c-myc was markedly higher in HepG2/pcDNA3-X cells than in HepG2 and HepG2/pcDNA3 cells （P〈0.05 and P〈0.01）.CONCLUSION： HBV X gene can impair cell proliferation capacity, improve cell apoptosis, and upregulate expression of apoptosis factors. The intervention of HBV X gene on the expression of apoptosis factors may be a possible mechanism responsible for the change in cell apoptosis and proliferation.展开更多
Background Our previous studies have indicated that the beneficial effects of grafting neural stem cells （NSCs） overexpressing glial cell line-derived neurotrophic factor （GDNF） in rats after stroke. However, the ...Background Our previous studies have indicated that the beneficial effects of grafting neural stem cells （NSCs） overexpressing glial cell line-derived neurotrophic factor （GDNF） in rats after stroke. However, the underlying mechanisms are highly debatable. In this study, we investigated whether neurogenesis, Akt, and extracellular signal- regulated kinase 1/2 （Erkl/2） signaling were involved in this process. Methods Transient ischemic stroke were induced by occluding middle cerebral artery for 2 hours and reperfusion. At 3 days after reperfusion, GDNF/NSCs, NSCs, and vehicle were administered. Immunohistochemical staining was used to evaluate neurogenesis by nestin antibody; phosphorylation of Akt and Erkl/2 was investigated by Western blotting analysis. Results Transplantation of GDNF/NSCs and NSCs significantly increased nestin-positive cells compared to control group （vehicle） from 1 to 7 weeks after reperfusion, and GDNF/NSCs showed stronger effect than NSCs at 2 and 3 weeks after reperfusion. Meanwhile, enhanced phosphorylation level of Erkl/2 was observed in the GDNF/NSCs and NSCs groups compared with control group, and phosphorylation level of Erkl/2 in GDNF/NSCs group was remarkably higher than that of NSCs group at any given time. In contrast, expression of mitogen-activated protein kinase phosphatase-1 （MKP-1）, known as inhibitor of Erkl/2 signaling, was significantly decreased in the GDNF/NSCs and NSCs groups compared with the control group. Moreover, much enhanced and prolonged phosphorylation level of Akt of GDNF/NSCs group was detected compared with control and NSCs group. Conclusion Grafting GDNF/NSCs enhances neurogenesis and activates Akt and Erkl/2 signaling, that may provide the potential for GDNF/NSCs in stroke treatment.展开更多
Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important loc...Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important location of neural stem cells, regulate survival, proliferation and differentiation of neural stem cells. However, the effects of activated glial cells on neural stem cells remain unclear. In the present study, we explored the effects of activated astrocytes and microglia on neural stem cells in vitro stroke models. We also investigated the effects of combined transplantation of neural stem cells and glial cells after stroke in rats. In a Transwell co-culture system, primary cultured astrocytes, microglia or mixed glial cells were exposed to glutamate or H_2O_2 and then seeded in the upper inserts, while primary neural stem cells were seeded in the lower uncoated wells and cultured for 7 days. Our results showed that microglia were conducive to neurosphere formation and had no effects on apoptosis within neurospheres, while astrocytes and mixed glial cells were conducive to neurosphere differentiation and reduced apoptosis within neurospheres, regardless of their pretreatment. In contrast, microglia and astrocytes induced neuronal differentiation of neural stem cells in differentiation medium, regardless of their pretreatment, with an exception of astrocytes pretreated with H_2O_2. Rat models of ischemic stroke were established by occlusion of the middle cerebral artery. Three days later, 5 × 10~5 neural stem cells with microglia or astrocytes were injected into the right lateral ventricle. Neural stem cell/astrocyte-treated rats displayed better improvement of neurological deficits than neural stem cell only-treated rats at 4 days after cell transplantation. Moreover, neural stem cell/microglia-, and neural stem cell/astrocyte-treated rats showed a significant decrease in ischemic volume compared with neural stem celltreated rats. These findings indicate that microglia and astrocytes exert different e展开更多
Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectros...Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectroscopic techniques.In vitro,compounds 1 and 2 were found to show signifcant cytotoxic activity against selected cancer cells,including P-388,HONE-1 and HT-29.展开更多
Designing a heterojunction photocatalyst to improve the separation efficiency of photogenerated electrons and holes is of great significance to improve the hydrogen production efficiency.In this work,we report a ratio...Designing a heterojunction photocatalyst to improve the separation efficiency of photogenerated electrons and holes is of great significance to improve the hydrogen production efficiency.In this work,we report a rational design to grow ZnIN_(2)S_(4)on Mo-MOF-derived N-doped C-coated MoO_(2)(MOZIS),and it has excellent photocatalytic hydrogen production with triethanolamine(TEOA)as sacrificial agent.N-doped C improves the electron transport efficiency between MoO_(2)and ZnIN_(2)S_(4)·The systematic study shows that MOZIS has good properties to promote the effective separation and transfer of photocatalytic charges,which is attributed to the tight contact interface and good energy band structure between MoO_(2)and ZnlN_(2)S_(4).The optimized nanocomposites have a high hydrogen production efficiency of 10.89 mmol·g^(-1)(4 h)under visible light.MOF-derived N-doped C-coated MoO_(2)is an effective strategy to improve the photocatalytic hydrogen production efficiency of ZnIN_(2)S_(4).展开更多
In this paper,we study the partial multi-label(PML)image classification problem,where each image is annotated with a candidate label set consisting of multiple relevant labels and other noisy labels.Existing PML metho...In this paper,we study the partial multi-label(PML)image classification problem,where each image is annotated with a candidate label set consisting of multiple relevant labels and other noisy labels.Existing PML methods typically design a disambiguation strategy to filter out noisy labels by utilizing prior knowledge with extra assumptions,which unfortunately is unavailable in many real tasks.Furthermore,because the objective function for disambiguation is usually elaborately designed on the whole training set,it can hardly be optimized in a deep model with stochastic gradient descent(SGD)on mini-batches.In this paper,for the first time,we propose a deep model for PML to enhance the representation and discrimination ability.On the one hand,we propose a novel curriculum-based disambiguation strategy to progressively identify ground-truth labels by incorporating the varied difficulties of different classes.On the other hand,consistency regularization is introduced for model training to balance fitting identified easy labels and exploiting potential relevant labels.Extensive experimental results on the commonly used benchmark datasets show that the proposed method significantlyoutperforms the SOTA methods.展开更多
The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage t...The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage test combined with the AE theory on rock damage. During different mining courses, the degree of wall rock suffered from mining disturbed process in mined-out area was different, so did the AE density of initial damage and fracture. Some characteristic parameters, including large events, total events, and energy rate, presented fluctuations with temporal and spatial change and take on a certain extent statistic relation. Subsequently, the percent of damage degree was defined and divided into 4 stages, and the localization damage and deformation characteristics of surrounding rock in mined-out area and coal pillars were analyzed quantitatively.展开更多
Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode m...Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Manganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high electrical conductivity.In this work,MnSe and ReS_(2) core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS_(2)) have been successfully synthesized from growing ReS_(2) nanosheets array on the surface of MnSe@NC nano wires,which present excellent Na^(+)/K^(+) storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g^(-1) was maintwined after 400 cycles at the current density of 1.0 A·g^(-1).Besides,it could also keep 120 mAh·g^(-1) specific capacity after 900 cycles at 1.0 A·g^(-1) for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-dimensional(1D-2D) hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.展开更多
5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TE...5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA demethylation.In this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,respectively.Additionally,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),respectively.Various DNA demethylation pathways possess critical functional implications and roles in biological processes.This Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.展开更多
Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,simila...Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,similar to metal oxides and sulfides,also suffer from severe volume explosion during repeated charge/discharge processes,which results in the structure collapse and the following pulverization of electrode materials.Hence,it leads to poor cycle stability and influencing their further application.In order to solve these issues,some special strategies,including elemental doping,coupling with carbon materials,synthesis of the bimetal selenides with heterostructure,etc.,have been gradually applied to design novel electrode materials with outstanding electrochemical performance.Herein,the recent research progress on metal selenides as anodes for alkali ion batteries is summarized,including the regulation of crystal structure,synthesis strategies,modification methods,and electrochemical mechanisms and kinetics.Besides,the challenges of metal selenides and the perspective for future electrode material design are proposed.It is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries.展开更多
Excessive dexamethasone (Dex) administrated into pregnant mice during critical periods of palatal development can produce a high incidence of cleft palate. Its mechanisms remain unknown. Vitamin B12 has been shown to ...Excessive dexamethasone (Dex) administrated into pregnant mice during critical periods of palatal development can produce a high incidence of cleft palate. Its mechanisms remain unknown. Vitamin B12 has been shown to antagonize the tera- togenic effects of Dex, which, however, remains controversial. In this study, we investigated the effects of Dex and vitamin B12 on murine embryonic palatal shelf fusion using organ culture of murine embryonic shelves. The explanted palatal shelves on em- bryonic day 14 (E14) were cultured for 24, 48, 72 or 96 h in different concentrations of Dex and/or vitamin B12. The palatal shelves were examined histologically for the morphological alterations on the medial edge epithelium (MEE) and fusion rates among different groups. It was found that the palatal shelves were not fused at 72 h or less of culture in Dex group, while they were completely fused in the control and vitamin B12-treated groups at 72 and 96 h, respectively. The MEE still existed and proliferated. In Dex+vitamin B12 group the palatal shelves were fused at each time point in a similar rate to controls. These results may suggest that Dex causes teratogenesis of murine embryonic palatal shelves and vitamin B12 prevents the teratogenic effect of Dex on palatogenesis on murine embryos in vitro.展开更多
基金financially supported by the National Basic Research Program of China (2011CB100506)the China Agriculture Research System-Wheat (CARS-03-02A)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences (KSCX2-EW-N-08)Research Fund of State Key Laboratory of Soil and Sustainable Agriculture, Nanjing Institute of Soil Science, Chinese Academy of Sciences (Y412201401)
文摘Cropland productivity has been significantly impacted by soil acidification resulted from nitrogen （N） fertilization, especially as a result of excess ammoniacal N input. With decades＇ intensive agricultural cultivation and heavy chemical N input in the Huang-Huai-Hai Plain, the impact extent of induced proton input on soil pH in the long term was not yet clear. In this study, acidification rates of different soil layers in the soil profile （0-120 cm） were calculated by pH buffer capacity （pHBC） and net input of protons due to chemical N incorporation. Topsoil （0-20 cm） pH changes of a long-term fertilization field （from 1989） were determined to validate the predicted values. The results showed that the acid and alkali buffer capacities varied significantly in the soil profile, averaged 692 and 39.8 mmolc kg-1 pH-1, respectively. A significant （P〈0.05） correlation was found between pHRC and the content of calcium carbonate. Based on the commonly used application rate of urea （500 kg N ha-1 yr-1）, the induced proton input in this region was predicted to be 16.1 kmol ha-1 yr-1, and nitrification and plant uptake of nitrate were the most important mechanisms for proton producing and consuming, respectively. The acidification rate of topsoil （0-20 cm） was estimated to be 0.01 unit pH yr-1 at the assumed N fertilization level. From 1989 to 2009, topsoil pH （0-20 cm） of the long-term fertilization field decreased from 8.65 to 8.50 for the PK （phosphorus, 150 kg P205 ha-1 yr-1; potassium, 300 kg K20 ha-1 yr-1; without N fertilization）, and 8.30 for NPK （nitrogen, 300 kg N ha-1 yr-1; phosphorus, 150 kg P2Os ha-1 yr-1; potassium, 300 kg K20 ha -1 yr-1）, respectively. Therefore, the apparent soil acidification rate induced by N fertilization equaled to 0.01 unit pH yr-1, which can be a reference to the estimated result, considering the effect of atmospheric N deposition, crop biomass, field management and plant uptake of other nutrients and cations. As protons could be consum
基金supported by the National Natural Science Foundation of China(Grant No.11072193)the Fundamental Research Funds for the Central Universities(Grant No.2013G1502009)the China Postdoctoral Science Foundation(Grant No.20100481354)
文摘The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress （ Kf line）, and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests： the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural loess comprehensively and reasonably, a joint strength formula for structural loess was established. This formula comprehensively considers tensile and shear properties. Studies have shown that the tensile strength exhibits a decreasing trend with increasing water content. When the water content is constant, the tensile strength of the structurally intact soil is greater than that ofremolded soil. In the studies, no loss of the originally cured cohesion in the structurally intact soil samples was observed, given that the soil samples did not experience loading disturbance during the uniaxial compressive strength test, meaning there is a high initial structural strength. The results of the conventional triaxial shear strength test show that the water content is correlated with the strength of the structural loess. When the water content is low, the structural properties are strong, and when the water content is high, the structural properties are weak, which means that the water content and the ambient pressure have significant effects on the stress-strain relationship of structural loess. The established joint strength formula of structural loess effectively avoids overestimating the role of soil tensile strength in the traditional theory of Mohr-Coulomb strength.
基金grants from the National Science and Technology Major Project of China(No.2017ZX10203205)the National Natural Science Founds for Distinguished Young Scholar of China(No.81625003)+1 种基金the State Key Program of National Natural Science Foundation of China(No.81930016)the National Natural Science Foundation of China(No.81902407).
文摘Background:The downstaging of hepatocellular carcinoma(HCC)has been confirmed to benefit liver transplantation(LT)patients whose tumors are beyond the transplantation criteria.Milan criteria(MC),a tumor size and number-based assessment,is currently used as the endpoint in these patients.However,many studies believe that tumor biological behavior should be added to the evaluation criteria for downstaging efficacy.Hence,this study aimed to explore the feasibility of Hangzhou criteria(HC),which introduced tumor grading and alpha-fetoprotein in addition to tumor size and number,as an endpoint of downstaging.Methods:We performed a multicenter and retrospective study of 206 patients accepted locoregional therapy(LRT)as downstaging/bridge treatment prior to LT in three centers of China.Results:Recipients were divided into four groups:failed downstaging to the HC(group A,n=46),successful downstaging to the HC(group B,n=30),remained within the HC all the time(group C,n=113),and tumor progressed(group D,n=17).The 3-year HCC recurrence probabilities of groups B and C were not significantly different(10.3%vs.11.6%,P=0.87).The HCC recurrent rate was significantly higher in group A(52.3%)compared with that in group B/C(P<0.05).Seven patients(7/76,9.2%)whose tumor exceeded the the HC were successfully downstaged to the MC,and 39.5%(30/76)to the the HC.In group B,23 patients remained beyond the MC and their survivals were as well as those of patients within the MC.Conclusions:Compared to the MC,HC downstaging criteria can give more HCC patients access to LT and furthermore,the outcome of these patients is the same as those matching MC downstaging criteria.Hangzhou downstaging criteria therefore is applicable in clinical practice.
基金Supported by the Science and Technology Fund of Fujian Province, No. 99-Z-162
文摘AIM： To investigate the possible mechanism for HBV X gene to induce apoptosis of hepatocyte HL-7702 cells.METHODS： HBV X gene eukaryon expression vector pcDNA3-X was established and transfected into HL-7702 cells by lipid-mediated transfection, including transient and stable transfection. Positive clones were screened by incubating in the selective medium with 600 μg/mL G418 and named HL-7702/HBV-encoded X protein （HBx） cells. The expressions of Fas/FasL, Bax/Bcl-2, and c-myc mRNA were measured by semi-quantitative RT-PCR in HL-7702/HBx and control group, respectively.RESULTS： RT-PCR analysis confirmed that HBV X gene was transfected into HL-7702 cells successfully. By semiquantitative RT-PCR analysis, Bax and c-myc mRNA levels in HL-7702/HBx cells of transient transfection were significantly higher than those in control, FasL and c-myc mRNA levels in HL-7702/HBx cells of stable transfection were significantly higher than those in control, whereas the Bcl-2 mRNA levels in HL-7702/HBx cells of transient and stable transfection were significantly lower than thosein control.CONCLUSION： HBV X gene may promote the apoptosis of hepatocytes by regulating the expressions of Fas/FasL, Bax/Bcl-2, and c-myc gene in a dose-dependent manner.
基金supported by the Natural Science Foundation of Hebei Province,Nos.18967728D (to XQC),H2021423063 (to HXC)Youth Top Talent Project of Colleges and Universities in Hebei Province,No.BJ2021033 (to HXC)。
文摘Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson’s disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment of a variety of diseases. However, whether they can protect neurons in Parkinson’s disease by inhibiting microglia-mediated inflammatory responses is not yet known. In this study, exosomes were isolated from human umbilical cord mesenchymal stem cells and injected into a 6-hydroxydopamine-induced rat model of Parkinson’s disease. We found that the exosomes injected through the tail vein and lateral ventricle were absorbed by dopaminergic neurons and microglia on the affected side of the brain, where they repaired nigral-striatal dopamine system damage and inhibited microglial activation. Furthermore, in an in vitro cell model, pretreating lipopolysaccharide-stimulated BV2 cells with exosomes reduced interleukin-1β and interleukin-18 secretion, prevented the adoption of pyroptosis-associated morphology by BV2 cells, and increased the survival rate of SH-SY5Y cells. Potential targets for treatment with human umbilical cord mesenchymal stem cells and exosomes were further identified by high-throughput microRNA sequencing and protein spectrum sequencing. Our findings suggest that human umbilical cord mesenchymal stem cells and exosomes are a potential treatment for Parkinson’s disease, and that their neuroprotective effects may be mediated by inhibition of excessive microglial proliferation.
文摘AIM： To investigate the effect of hepatitis B virus （HBV） X gene on apoptosis and expressions of apoptosis factors in X gene-transfected HepG2 cells.METHODS： The HBV X gene eukaryon expression vector pcDNA3-X was transiently transfected into HepG2 cells by lipid-media transfection. Untransfected HepG2 and HepG2 transfected with pcDNA3 were used as controls. Expression of HBx in HepG2 was identified by RT-PCR. MTT and TUNEL were employed to measure proliferation and apoptosis of cells in.three groups. Semi-quantified RT-PCR was used to evaluate the expression levels of Fas/FasL, Bax/Bcl-xL, and c-myc in each group.RESULTS： HBV X gene was transfected into HepG2 cells successfully. RT-PCR showed that HBx was only expressed in HepG2/pcDNA3-X cells, but not expressed in HepG2 and HepG2/pcDNA3 cells. Analyzed by MTT, cell proliferationcapacity was obviously lower in HepG2/pcDNA3-X cells （0.08910±0.003164） than in HepG2 （0.14410±0.004927） and HepG2/pcDNA3 cells （0.12150±0.007159） （P〈0.05 and P〈0.01）. Analyzed by TUNEL, cell apoptosis was much more in HepG2/pcDNA3-X cells （980/2 000） than HepG2 （420/2 000）, HepG2/pcDNA3 cells （520/2 000） （P〈0.05 and P〈0.01）. Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasL was significantly higher in HepG2 cells transfected with HBx than in HepG2 and HepG2/pcDNA3 cells （P〈0.05 and P〈0.01）. Bax/Bcl-xL expression level was also elevated in HepG2/pcDNA3-X cells （P〈0.05 and P〈0.01）. Expression of c-myc was markedly higher in HepG2/pcDNA3-X cells than in HepG2 and HepG2/pcDNA3 cells （P〈0.05 and P〈0.01）.CONCLUSION： HBV X gene can impair cell proliferation capacity, improve cell apoptosis, and upregulate expression of apoptosis factors. The intervention of HBV X gene on the expression of apoptosis factors may be a possible mechanism responsible for the change in cell apoptosis and proliferation.
基金This study was supported by grants from State Key Laboratory of Medical Neurobiology, Fudan University, and the programs from the Ministry of Science and Technology of China （No. 2010CB945600 and No. 2011CB965100）, the National Natural Science Foundation of China （No. 81070987, No. 30971531）, Shanghai Science Foundation （No. 11PJ1407800）, and National Education Ministry （IRT1168）, International Science ＆ Technology Collaboration Program （No. 2011DF30010）.
文摘Background Our previous studies have indicated that the beneficial effects of grafting neural stem cells （NSCs） overexpressing glial cell line-derived neurotrophic factor （GDNF） in rats after stroke. However, the underlying mechanisms are highly debatable. In this study, we investigated whether neurogenesis, Akt, and extracellular signal- regulated kinase 1/2 （Erkl/2） signaling were involved in this process. Methods Transient ischemic stroke were induced by occluding middle cerebral artery for 2 hours and reperfusion. At 3 days after reperfusion, GDNF/NSCs, NSCs, and vehicle were administered. Immunohistochemical staining was used to evaluate neurogenesis by nestin antibody; phosphorylation of Akt and Erkl/2 was investigated by Western blotting analysis. Results Transplantation of GDNF/NSCs and NSCs significantly increased nestin-positive cells compared to control group （vehicle） from 1 to 7 weeks after reperfusion, and GDNF/NSCs showed stronger effect than NSCs at 2 and 3 weeks after reperfusion. Meanwhile, enhanced phosphorylation level of Erkl/2 was observed in the GDNF/NSCs and NSCs groups compared with control group, and phosphorylation level of Erkl/2 in GDNF/NSCs group was remarkably higher than that of NSCs group at any given time. In contrast, expression of mitogen-activated protein kinase phosphatase-1 （MKP-1）, known as inhibitor of Erkl/2 signaling, was significantly decreased in the GDNF/NSCs and NSCs groups compared with the control group. Moreover, much enhanced and prolonged phosphorylation level of Akt of GDNF/NSCs group was detected compared with control and NSCs group. Conclusion Grafting GDNF/NSCs enhances neurogenesis and activates Akt and Erkl/2 signaling, that may provide the potential for GDNF/NSCs in stroke treatment.
基金supported by the National Natural Science Foundation of China,Nos.81371213,81070987,30971531grants from the Ministry of Science and Technology of China,Nos.2010CB945600,2010CB945601(all to QLY)。
文摘Transplantation of neural stem cells(NSCs) can protect neurons in animal stroke models;however, their low rates of survival and neuronal differentiation limit their clinical application. Glial niches, an important location of neural stem cells, regulate survival, proliferation and differentiation of neural stem cells. However, the effects of activated glial cells on neural stem cells remain unclear. In the present study, we explored the effects of activated astrocytes and microglia on neural stem cells in vitro stroke models. We also investigated the effects of combined transplantation of neural stem cells and glial cells after stroke in rats. In a Transwell co-culture system, primary cultured astrocytes, microglia or mixed glial cells were exposed to glutamate or H_2O_2 and then seeded in the upper inserts, while primary neural stem cells were seeded in the lower uncoated wells and cultured for 7 days. Our results showed that microglia were conducive to neurosphere formation and had no effects on apoptosis within neurospheres, while astrocytes and mixed glial cells were conducive to neurosphere differentiation and reduced apoptosis within neurospheres, regardless of their pretreatment. In contrast, microglia and astrocytes induced neuronal differentiation of neural stem cells in differentiation medium, regardless of their pretreatment, with an exception of astrocytes pretreated with H_2O_2. Rat models of ischemic stroke were established by occlusion of the middle cerebral artery. Three days later, 5 × 10~5 neural stem cells with microglia or astrocytes were injected into the right lateral ventricle. Neural stem cell/astrocyte-treated rats displayed better improvement of neurological deficits than neural stem cell only-treated rats at 4 days after cell transplantation. Moreover, neural stem cell/microglia-, and neural stem cell/astrocyte-treated rats showed a significant decrease in ischemic volume compared with neural stem celltreated rats. These findings indicate that microglia and astrocytes exert different e
基金financially supported by the Natural Science Foundation of Shandong Province (No. ZR2009CZ004)
文摘Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectroscopic techniques.In vitro,compounds 1 and 2 were found to show signifcant cytotoxic activity against selected cancer cells,including P-388,HONE-1 and HT-29.
基金financially supported by the Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education(No.JKF21-08)the Open Project of Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education(No.BWPU2021KF05)+3 种基金the National Natural Science Foundation of China(No.62104003)the Natural Science Foundation of Anhui Province(No.1908085QB75)Anhui Provincial Scientific and Technological Major Project(No.18030801109)the Opening Project of Engineering Technology Research Center of Anhui Education Department for Energy Saving and Pollutant Control in metallurgical process(No.GKF20-7)。
文摘Designing a heterojunction photocatalyst to improve the separation efficiency of photogenerated electrons and holes is of great significance to improve the hydrogen production efficiency.In this work,we report a rational design to grow ZnIN_(2)S_(4)on Mo-MOF-derived N-doped C-coated MoO_(2)(MOZIS),and it has excellent photocatalytic hydrogen production with triethanolamine(TEOA)as sacrificial agent.N-doped C improves the electron transport efficiency between MoO_(2)and ZnIN_(2)S_(4)·The systematic study shows that MOZIS has good properties to promote the effective separation and transfer of photocatalytic charges,which is attributed to the tight contact interface and good energy band structure between MoO_(2)and ZnlN_(2)S_(4).The optimized nanocomposites have a high hydrogen production efficiency of 10.89 mmol·g^(-1)(4 h)under visible light.MOF-derived N-doped C-coated MoO_(2)is an effective strategy to improve the photocatalytic hydrogen production efficiency of ZnIN_(2)S_(4).
文摘In this paper,we study the partial multi-label(PML)image classification problem,where each image is annotated with a candidate label set consisting of multiple relevant labels and other noisy labels.Existing PML methods typically design a disambiguation strategy to filter out noisy labels by utilizing prior knowledge with extra assumptions,which unfortunately is unavailable in many real tasks.Furthermore,because the objective function for disambiguation is usually elaborately designed on the whole training set,it can hardly be optimized in a deep model with stochastic gradient descent(SGD)on mini-batches.In this paper,for the first time,we propose a deep model for PML to enhance the representation and discrimination ability.On the one hand,we propose a novel curriculum-based disambiguation strategy to progressively identify ground-truth labels by incorporating the varied difficulties of different classes.On the other hand,consistency regularization is introduced for model training to balance fitting identified easy labels and exploiting potential relevant labels.Extensive experimental results on the commonly used benchmark datasets show that the proposed method significantlyoutperforms the SOTA methods.
基金supported by the National Natural Science Foundation of China (No.10402033)
文摘The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage test combined with the AE theory on rock damage. During different mining courses, the degree of wall rock suffered from mining disturbed process in mined-out area was different, so did the AE density of initial damage and fracture. Some characteristic parameters, including large events, total events, and energy rate, presented fluctuations with temporal and spatial change and take on a certain extent statistic relation. Subsequently, the percent of damage degree was defined and divided into 4 stages, and the localization damage and deformation characteristics of surrounding rock in mined-out area and coal pillars were analyzed quantitatively.
基金financially supported by the National Natural Science Foundation of China (No.52101243)the Natural Science Foundation of Guangdong Province (No.2023A1515012619)the Science and Technology Planning Project of Guangzhou (No.202102010373)。
文摘Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Manganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high electrical conductivity.In this work,MnSe and ReS_(2) core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS_(2)) have been successfully synthesized from growing ReS_(2) nanosheets array on the surface of MnSe@NC nano wires,which present excellent Na^(+)/K^(+) storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g^(-1) was maintwined after 400 cycles at the current density of 1.0 A·g^(-1).Besides,it could also keep 120 mAh·g^(-1) specific capacity after 900 cycles at 1.0 A·g^(-1) for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-dimensional(1D-2D) hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.
基金supported by the National Natural Science Foundation of China(22074110)Guangdong Basic and Applied Basic Research Foundation(2022A1515110550)+2 种基金Central Public-interest Scientific Institution Basal Research Fund,South China Sea Fisheries Research institute,CAFS(No.2021TS02)Guangzhou Basic and Applied Basic Research Foundation(2023A04J1337)Central Public-interest Scientific Institution Basal Research Fund,CAFS(No.2023TD78).
文摘5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA demethylation.In this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,respectively.Additionally,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),respectively.Various DNA demethylation pathways possess critical functional implications and roles in biological processes.This Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.
基金supported by the National Natural Science Foundation of China(Nos.51563002 and 52101243)the"100-level"Innovative Talents Project of Guizhou Province,China(No.[2016]5653)+1 种基金the Natural Science Foundation of Guangdong Province(No.2020A1515010886)the Science and Technology Planning Project of Guangzhou(No.202102010373)。
文摘Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,similar to metal oxides and sulfides,also suffer from severe volume explosion during repeated charge/discharge processes,which results in the structure collapse and the following pulverization of electrode materials.Hence,it leads to poor cycle stability and influencing their further application.In order to solve these issues,some special strategies,including elemental doping,coupling with carbon materials,synthesis of the bimetal selenides with heterostructure,etc.,have been gradually applied to design novel electrode materials with outstanding electrochemical performance.Herein,the recent research progress on metal selenides as anodes for alkali ion batteries is summarized,including the regulation of crystal structure,synthesis strategies,modification methods,and electrochemical mechanisms and kinetics.Besides,the challenges of metal selenides and the perspective for future electrode material design are proposed.It is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries.
基金Project (No. 30530730) supported by the National Natural ScienceFoundation of China
文摘Excessive dexamethasone (Dex) administrated into pregnant mice during critical periods of palatal development can produce a high incidence of cleft palate. Its mechanisms remain unknown. Vitamin B12 has been shown to antagonize the tera- togenic effects of Dex, which, however, remains controversial. In this study, we investigated the effects of Dex and vitamin B12 on murine embryonic palatal shelf fusion using organ culture of murine embryonic shelves. The explanted palatal shelves on em- bryonic day 14 (E14) were cultured for 24, 48, 72 or 96 h in different concentrations of Dex and/or vitamin B12. The palatal shelves were examined histologically for the morphological alterations on the medial edge epithelium (MEE) and fusion rates among different groups. It was found that the palatal shelves were not fused at 72 h or less of culture in Dex group, while they were completely fused in the control and vitamin B12-treated groups at 72 and 96 h, respectively. The MEE still existed and proliferated. In Dex+vitamin B12 group the palatal shelves were fused at each time point in a similar rate to controls. These results may suggest that Dex causes teratogenesis of murine embryonic palatal shelves and vitamin B12 prevents the teratogenic effect of Dex on palatogenesis on murine embryos in vitro.
