The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizin...The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.展开更多
The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of...The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of Austrophorocera hirsute(Mesnil,1946),syn.nov.A key to the two Chinese species is provided.展开更多
The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop pro...The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.展开更多
Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense ...Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense planting conditions.Future model modifications and corrections should focus on the leaf area index dynamics and harvest index.展开更多
Gastric cancer(GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis,as...Gastric cancer(GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis,as best exemplified by elucidating the fundamental role of several major signaling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these signaling pathways,such as gene mutations,copy number variants,aberrant gene methylation and histone modification,nucleosome positioning,and microRNAs. Some of these genetic/epigenetic alterations represent effective diagnostic and prognostic biomarkers and therapeutic targets for GC. This information has now opened unprecedented opportunities for better understanding of the molecular mechanisms of gastric carcinogenesis and the development of novel therapeutic strategies for this cancer. The pathogenetic mechanisms of GC are the focus of this review.展开更多
Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yiel...Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.展开更多
This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization ...This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization approaches to detect and observe the CO2-formation fluid displacement mechanism at the micro-scale, namely, magnetic resonance imaging, X-ray computed tomography and fabricated micromodels, but they are not capable of investigating the dis- placement process at the nano-scale. Though a lab-on-chip approach for the direct visualization of the fluid flow behaviour in nanoscale channels has been developed using an advanced epi-fluorescence microscopy method combined with a nanofluidic chip, it is still a qualitative analysis method. The lattice Boltzmann method （LBM） can simulate the CO2 displacement processes in a two-dimensional or three-dimensional （3D） pore structure, but until now, the CO2 displace- ment mechanisms had not been thoroughly investigated and the 3D pore structure of real rock had not been directly taken into account in the simulation of the CO2 displacement process. The status of research on the applications of CO2 displacement to enhance shale gas recovery is also analyzed in this paper. The coupling of molecular dynamics and LBM in tandem is proposed to simulate the CO2-shale gas displacement process based on the 3D digital model of shale obtained from focused ion beams and scanning electron microscopy.展开更多
AIM:To investigate the effect of plasmapheresis via the portal vein for"small-for-size"syndrome(SFSS)aided by extracorporeal continuous portal diversion(ECPD).METHODS:Extensive or total hepatectomy in the pi...AIM:To investigate the effect of plasmapheresis via the portal vein for"small-for-size"syndrome(SFSS)aided by extracorporeal continuous portal diversion(ECPD).METHODS:Extensive or total hepatectomy in the pig is usually adopted as a postoperative liver failure(PLF)or SFSS model.In this study,animals which underwent85%-90%hepatectomy were randomized into either the Systemic group(n=7)or the Portal group(n=7).In the Systemic group,all pigs received temporal plasmapheresis(PP)via the extracorporeal catheter circuit(systemic to systemic circulation)from 24 to 30 h posthepatectomy(PH);in the Portal group,all pigs received ECPD to divert partial portal vein flow(PVF)to the systemic circulation after hepatectomy,then converted to temporal PP from 24 to 30 h PH,and subsequently converted to ECPD again until 48 h PH.In the Portal group,the PVF was preserved at 3.0-3.3 times that of the baseline value,similar to that following 70%hepatectomy,which was regarded as the optimal PVF to the hypertrophic liver remnant.At 48 h PH,all pigs were re-opened and the portal vein pressure(PVP),PVF,and HAF(hepatic artery flow)were measured,and then diversion of the portal venous flow was terminated.After1 h the PVP,PVF,and HAF were re-measured.The portal hemodynamic changes,liver injury,liver regeneration and bacterial/lipopolysaccharide(LPS)translocation were evaluated in the two groups.RESULTS:The PVP in the Portal group was significantly lower than that in the Systemic group during the time period from 2 to 49 h PH(P<0.05).Serum alanine aminotransferase(ALT),total bilirubin(TB)and ammonia were significantly reduced in the Portal group compared with the Systemic group from 24 to 48 h PH(P<0.05).The Portal group may have attenuated sinusoidal endothelial injury and decreased the level of HA compared with the Systemic group.In the Systemic group,there was significant sinusoidal dilation,hydropic changes in hepatocytes and hemorrhage into the hepatic parenchyma,and the sinusoidal endothelial lining was partially destroyed and detached into the sinusoidal space.CD31immunostaining revealed significant destruction of the endothelial lining.In the Portal group,there was no intraparenchymal hemorrhage and the sinusoidal endothelial cells and hepatocytes were well preserved.CD31immunostaining was mild which indicated less destruction of the endothelial lining.HA was significantly decreased in the Portal group compared with the Systemic group from 2 to 48 h PH.The rate of liver remnant regeneration was elevated,while apoptosis was attenuated in the Portal group compared with the Systemic group.Thymidine kinase activity was much higher in the Portal group than in the Systemic group at 48 h PH.The PCNA index was significantly increased and the apoptotic index was significantly decreased in the Portal group compared with the Systemic group.Bacterial translocation and endotoxin,as well as the inflammatory response,were significantly attenuated in the Portal group compared with the Systemic group.LPS,tumor necrosis factor-and interleukin-6 levels were all significantly decreased in the Portal group compared with the Systemic group from 24 to48 h PH,while bacterial DNA level was significantly decreased from 2 to 48 h PH.CONCLUSION:PP plus ECPD via the portal vein can attenuate toxic load and hyperperfusion injury,and should be undertaken instead of PP via the systemic circulation in SFSS or PLF.展开更多
AIM: To investigate the association between colorectal cancer(CRC) genetic susceptibility variants and esophageal cancer in a Chinese Han population.METHODS: A case-control study was conducted including 360 esophageal...AIM: To investigate the association between colorectal cancer(CRC) genetic susceptibility variants and esophageal cancer in a Chinese Han population.METHODS: A case-control study was conducted including 360 esophageal cancer patients and310 healthy controls. Thirty-one single-nucleotide polymorphisms(SNPs) associated with CRC risk from previous genome-wide association studies were analyzed. SNPs were genotyped using Sequenom Mass-ARRAY technology, and genotypic frequencies in controls were tested for departure from HardyWeinberg equilibrium using a Fisher's exact test. The allelic frequencies were compared between cases and controls using a χ 2 test. Associations between the SNPs and the risk of esophageal cancer were tested using various genetic models(codominant, dominant,recessive, overdominant, and additive). ORs and95%CIs were calculated by unconditional logistic regression with adjustments for age and sex.RESULTS: The minor alleles of rs1321311 and rs4444235 were associated with a 1.53-fold(95%CI:1.15-2.06; P = 0.004) and 1.28-fold(95%CI: 1.03-1.60;P = 0.028) increased risk of esophageal cancer in the allelic model analysis, respectively. In the genetic model analysis, the C/C genotype of rs3802842 was associated with a reduced risk of esophageal cancer in the codominant model(OR = 0.52, 95%CI:0.31-0.88; P = 0.033) and recessive model(OR =0.55, 95%CI: 0.34-0.87; P = 0.010). The rs4939827C/T-T/T genotype was associated with a 0.67-fold(95%CI: 0.46-0.98; P = 0.038) decreased esophageal cancer risk under the dominant model. In addition,rs6687758, rs1321311, and rs4444235 were associated with an increased risk. In particular, the T/T genotype of rs1321311 was associated with an 8.06-fold(95%CI: 1.96-33.07; P = 0.004) increased risk in the codominant model.CONCLUSION: These results provide evidence that known genetic variants associated with CRC risk confer risk for esophageal cancer, and may bring risk for other digestive system tumors.展开更多
In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to incre...In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to increase maize yield in this area,because it increases topsoil temperature and moisture content as well as water use efficiency.However,the physiological and anatomical bases of maize yield improvement with plastic film mulching are not well understood.The effects of plastic film mulching and planting density on maize yield,photosynthetic characteristics,respiration,leaf anatomy,and root growth were studied in a two-year field experiment conducted on the Loess Plateau of China in 2017 and 2018.The experiment used a split-split plot design with two mulching treatments(plastic film mulching and no mulching),two planting densities(7.5×104 and10.5×104 plants ha-1),and two maize cultivars,Zhengdan 958 and Xianyu 335.Compared with no mulching,plastic film mulching increased maize yields by 31.1%–46.4%in 2017 and3.6%–34.7%in 2018.Compared with low planting density,high planting density significantly increased and slightly reduced yields of both cultivars in the dry year 2017 and the rainy year 2018,respectively.Plastic film mulching increased photosynthesis and respiration as well as leaf stomatal density and aperture.Photosynthetic rate,dark respiration,and stomatal conductance and aperture were lower at high planting than at low planting density.Maize yield was positively correlated with photosynthesis,dark respiration,and stomatal aperture.Mulching increased root dry weight and length in the 0–20 cm soil layer and root activity at maturity.Overall,the changes in root growth and leaf anatomy resulted in increased photosynthesis and dark respiration,and the increased photosynthesis contributed to the increase in grain yield and biomass production under plastic film mulching conditions.Our results increase understanding of the physiological mechanisms by which plastic film mulching increases maize yield in water-and temperature-limited areas.展开更多
The appropriate fuze-warhead coordination method is important to improve the damage efficiency of air defense missiles against aircraft targets. In this paper, an adaptive fuze-warhead coordination method based on the...The appropriate fuze-warhead coordination method is important to improve the damage efficiency of air defense missiles against aircraft targets. In this paper, an adaptive fuze-warhead coordination method based on the Back Propagation Artificial Neural Network(BP-ANN) is proposed, which uses the parameters of missile-target intersection to adaptively calculate the initiation delay. The damage probabilities at different radial locations along the same shot line of a given intersection situation are calculated, so as to determine the optimal detonation position. On this basis, the BP-ANN model is used to describe the complex and highly nonlinear relationship between different intersection parameters and the corresponding optimal detonating point position. In the actual terminal engagement process, the fuze initiation delay is quickly determined by the constructed BP-ANN model combined with the missiletarget intersection parameters. The method is validated in the case of the single-shot damage probability evaluation. Comparing with other fuze-warhead coordination methods, the proposed method can produce higher single-shot damage probability under various intersection conditions, while the fuzewarhead coordination effect is less influenced by the location of the aim point.展开更多
Accurate leaf area simulation is critical for the performance of crop growth models. Area of fully expanded individual leaves of maize hybrids released before 1995 (defined as old hybrids) has been simulated using a b...Accurate leaf area simulation is critical for the performance of crop growth models. Area of fully expanded individual leaves of maize hybrids released before 1995 (defined as old hybrids) has been simulated using a bell-shaped function (BSF) and the relationship between its parameters and total leaf number (TLNO). However, modern high-yielding maize hybrids show different canopy architectures. The function parameters calibrated for old hybrids will not accurately represent modern hybrids. In this study, we evaluated these functions using a dataset including old and modern hybrids that have been widely planted in China in recent years. Maximum individual leaf area (Y_0) and corresponding leaf position (X_0) were not predicted well by TLNO (R^2= 0.56 and R^2= 0.70) for modern hybrids. Using recalibrated shape parameters a and b with values of Y_0 and X_0 for modern hybrids, the BSF accurately predicted individual leaf area (R^2= 0.95–0.99) and total leaf area of modern hybrids (R^2= 0.98). The results show that the BSF is still a robust way to predict the fully expanded leaf area of maize when parameters a and b are modified and Y_0 and X_0 are fitted. Breeding programs have led to increases in TLNO of maize but have not altered Y_0 and X_0, reducing the correlation between Y_0, X_0, and TLNO. For modern hybrids, the values of Y_0 and X_0 are hybrid-specific. Modern hybrids tend to have less-negative values of parameter a and more-positive values of parameter b in the leaf profile. Growth conditions, such as plant density and environmental conditions, also affect the fully expanded leaf area but were not considered in the original published equations. Thus, further research is needed to accurately estimate values of Y_0 and X_0 of individual modern hybrids to improve simulation of maize leaf area in crop growth models.展开更多
Magnesium(Mg)is a promising biomedical metal because of its biodegradability.The crevice between tissue and Mg implant can not be neglected in some implantation sites due to inducing crevice corrosion of Mg.In this pa...Magnesium(Mg)is a promising biomedical metal because of its biodegradability.The crevice between tissue and Mg implant can not be neglected in some implantation sites due to inducing crevice corrosion of Mg.In this paper,a new single mold was designed to build the in vitro experimental setup and four kinds of solutions,i.e.the deionized water(DW),the 0.9 wt.%sodium chloride solution(NaCl),the phosphate buffer saline(PBS)and the modified simulated body fluid(m-SBF)were used to explore necessary factors of crevice corrosion in Mg.It was observed that crevice corrosion in Mg sheets would occur in NaCl and PBS solution under 0.2,0.5 and 0.8 mm crevice thickness.And it was found that there were two necessary factors,i.e.chloride ion and crevice dimension,in crevice corrosion.For the high-purity Mg cannulated screws,crevice corrosion could occur inside tunnel when immersed in PBS.展开更多
To solve the special requirements of the high orbit optical remote sensing satellite for the thermal deformation of the platform the thermal deformation test and measurement scheme of the satellite platform is designe...To solve the special requirements of the high orbit optical remote sensing satellite for the thermal deformation of the platform the thermal deformation test and measurement scheme of the satellite platform is designed. Through the comparative analysis of test results the rationality of the thermal deformation design of the platform structure is verified. The results of thermal deformation measurement show that the maximum deformation of A camera mounting surface is 57.5〃 and the maximum deformation of B camera mounting surface points to 79.3〃 which can be used as the basis for thermal deformation prediction of satellite during the orbit operation.展开更多
The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft targets.In this paper,three missile terminal attitude selection methods are propo...The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft targets.In this paper,three missile terminal attitude selection methods are proposed to solve the problem of terminal attitude selection in different situations according to their respective evaluation indexes.The MVE-based method uses the damage probability of each detonation point around the aircraft at a given attitude of missile to calculate the Mean Volume of Effectiveness(MVE)at the corresponding attitude,and then uses the MVE for different attitudes to select the terminal strike attitude.The detonation position-based method addresses the case where the missile detonation position can be assessed in advance.Given the effects of missile guidance errors and fuze activation position errors,Monte Carlo simulations are used to calculate the damage probability of aircraft with different strike attitudes,from which the terminal strike attitude is selected.The BP-ANN model-based method uses the constructed Back Propagation Artificial Neural Network(BP-ANN)model instead of simulation to calculate the evaluation indexes in the corresponding cases of MVE-based method and Detonation position-based method,which can improve the efficiency of attitude selection.Simulations are conducted for different scenarios to verify the feasibility and effectiveness of the proposed method.展开更多
The decreasing cost of solar photovoltaics(PVs)and battery storage systems is driving their adoption in the residential distribution system,where more consumers are becoming prosumers.Accompanying this trend is the po...The decreasing cost of solar photovoltaics(PVs)and battery storage systems is driving their adoption in the residential distribution system,where more consumers are becoming prosumers.Accompanying this trend is the potential roll-out of home energy management systems(HEMSs),which provide a means for prosumers to respond to externalities such as energy price,weather,and energy demands.However,the economic operation of prosumers can affect grid security,especially when energy prices are extremely low or high.Therefore,it is paramount to design a framework that can accommodate the interests of the key stakeholders in distribution systems—namely,the network operator,prosumer,and aggregator.In this paper,a novel transactive energy(TE)-based operational framework is proposed.Under this frame-work,aggregators interact with the distribution grid operator through a negotiation process to ensure network security,while at the lower level,prosumers submit their schedule to the aggregator through the HEMS.If network security is at risk,aggregators will send an additional price component representing the cost of security(CoS)to the prosumer to stimulate further response.The simulation results show that the proposed framework can effectively ensure the economic operation of aggregators and prosumers in distribution systems while maintaining grid security.展开更多
High-throughput SNP detection microarrays were used here to explore the relationship between 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T and the risk of gastric carcinoma among population...High-throughput SNP detection microarrays were used here to explore the relationship between 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T and the risk of gastric carcinoma among population in Jiangsu region,by genotyping the specimens from 170 patients with gastric carcinoma and 140 age-and sex- matched control subjects.PCR products were spotted onto a 3-aminopropyltriethoxysilane coated glass slide to fabricate a microarray,then interrogated by hybridization with dual-color probes (Cy3,CyS) to determine the SNP genotype of each sample,and the relation between the genotypes and the risk of gastric carcinoma was analyzed.The frequencies of C677T genotype were CC(47.9%),CT(40%),CT(12.1%) in control group and CC(35.9%),CT(45.9%),TT(18.2%) in gastric carcinoma group,respectively.The individuals with 677CT+TT genotype group or 677TT had a 1.67-fold (95% CI:1.06-2.64) or 2.67-fold (95% CI:1.382-5.341) increased risk to develop gastric carcinoma compared with those having 677CC genotype. It was shown that the single nucleotide polymorphisms in the MTHFR gene are associated with the risk of gastric carcinoma in the Chinese population.展开更多
基金supported by the grants from National Key Research and Development Program of China(2023YFD2303300)China Agriculture Research System(CARS-02-15)the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202004).
文摘The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.
基金supported by the Science&Technology Fundamental Resources Investigation Program(2023FY100302)the National Natural Science Foundation of China(32470459+1 种基金31272279)the Natural Science Foundation of Liaoning Province(2022-BS-332).
文摘The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of Austrophorocera hirsute(Mesnil,1946),syn.nov.A key to the two Chinese species is provided.
基金supported by the National Natural Science Foundation of China(32172118)the National Key Research and Development Program of China(2016YFD0300110 and 2016YFD0300101)+1 种基金the Basic Scientific Research Fund of Chinese Academy of Agricultural Sciences,China(S2022ZD05)the Agricultural Science and Technology Innovation Program,China(CAAS-ZDRW202004)。
文摘The distributions of light and nitrogen within a plant's canopy reflect the growth adaptation of crops to the environment and are conducive to improving the carbon assimilation ability.So can the yield in crop production be maximized by improving the light and nitrogen distributions without adding any additional inputs?In this study,the effects of different nitrogen application rates and planting densities on the canopy light and nitrogen distributions of two highyielding maize cultivars(XY335 and DH618)and the regulatory effects of canopy physiological characteristics on radiation use efficiency(RUE)and yield were studied based on high-yield field experiments in Qitai,Xinjiang Uygur Autonomous Region,China,during 2019 and 2020.The results showed that the distribution of photosynthetically active photon flux density(PPFD)in the maize canopy decreased from top to bottom,while the vertical distribution of specific leaf nitrogen(SLN)initially increased and then decreased from top to bottom in the canopy.When SLN began to decrease,the PPDF values of XY335 and DH618 were 0.5 and 0.3,respectively,corresponding to 40.6 and49.3%of the total leaf area index(LAI).Nitrogen extinction coefficient(K_(N))/light extinction coefficient(K_(L))ratio in the middle and lower canopy of XY335(0.32)was 0.08 higher than that of DH618(0.24).The yield and RUE of XY335(17.2 t ha^(-1)and 1.8g MJ^(-1))were 7.0%(1.1 t ha^(-1))and 13.7%(0.2 g MJ^(-1))higher than those of DH618(16.1 t ha^(-1)and 1.6 g MJ^(-1)).Therefore,better light conditions(where the proportion of LAI in the upper and middle canopy was small)improved the light distribution when SLN started to decline,thus helping to mobilize the nitrogen distribution and maintain a high K_(N)and K_(N)/K_(L)ratio.In addition,K_(N)/K_(L)was a key parameter for yield improvement when the maize nutrient requirements were met at 360 kg N ha^(-1).At this level,an appropriately optimized high planting density could promote nitrogen utilization and produce higher yields and greater efficiency.The results of this study will be important for achieving high maize yields and the high efficiency cultivation and breeding of maize in the future.
基金supported by the National Key Research and Development Program of China(2023YFD1900603)the National Natural Science Foundation of China(32172118)the China Agriculture Research System of MOF and MARA(CARS-02)。
文摘Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense planting conditions.Future model modifications and corrections should focus on the leaf area index dynamics and harvest index.
基金Supported by National Key Program for Developing Basic Research,No.2010CB933903the National Natural Science Foundation of China,No.81171969,No.81272933 and No.81372217the Fundamental Research Funds for the Central Universities
文摘Gastric cancer(GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis,as best exemplified by elucidating the fundamental role of several major signaling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these signaling pathways,such as gene mutations,copy number variants,aberrant gene methylation and histone modification,nucleosome positioning,and microRNAs. Some of these genetic/epigenetic alterations represent effective diagnostic and prognostic biomarkers and therapeutic targets for GC. This information has now opened unprecedented opportunities for better understanding of the molecular mechanisms of gastric carcinogenesis and the development of novel therapeutic strategies for this cancer. The pathogenetic mechanisms of GC are the focus of this review.
基金research support from the National Key Research and Development Program of China (2016YFD0300110, 2016YFD0300101)the National Basic Research Program of China (2015CB150401)+2 种基金the National Natural Science Foundation of China (31360302)the Science and Technology Program of the Sixth Division of Xinjiang Construction Corps in China (1703)the Agricultural Science and Technology Innovation Program for financial support.
文摘Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.
基金The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China （Grant Nos. 51374213 and 51674251）, the State Key Research Development Program of China （Grant No. 2016YFC0600705）, the National Natural Science Fund for Distinguished Young Scholars of China （Grant No. 51125017）, the Fund for Innovative Research and Development Group Program of Jiangsu Province （Grant No. 2014- 27）, the Science Fund for Creative Research Groups of the National Natural Science Foundation of China （Grant No. 51421003）, and the Priority Academic Program Development of the Jiangsu Higher Education Institutions （PAPD 2014）.
文摘This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization approaches to detect and observe the CO2-formation fluid displacement mechanism at the micro-scale, namely, magnetic resonance imaging, X-ray computed tomography and fabricated micromodels, but they are not capable of investigating the dis- placement process at the nano-scale. Though a lab-on-chip approach for the direct visualization of the fluid flow behaviour in nanoscale channels has been developed using an advanced epi-fluorescence microscopy method combined with a nanofluidic chip, it is still a qualitative analysis method. The lattice Boltzmann method （LBM） can simulate the CO2 displacement processes in a two-dimensional or three-dimensional （3D） pore structure, but until now, the CO2 displace- ment mechanisms had not been thoroughly investigated and the 3D pore structure of real rock had not been directly taken into account in the simulation of the CO2 displacement process. The status of research on the applications of CO2 displacement to enhance shale gas recovery is also analyzed in this paper. The coupling of molecular dynamics and LBM in tandem is proposed to simulate the CO2-shale gas displacement process based on the 3D digital model of shale obtained from focused ion beams and scanning electron microscopy.
文摘AIM:To investigate the effect of plasmapheresis via the portal vein for"small-for-size"syndrome(SFSS)aided by extracorporeal continuous portal diversion(ECPD).METHODS:Extensive or total hepatectomy in the pig is usually adopted as a postoperative liver failure(PLF)or SFSS model.In this study,animals which underwent85%-90%hepatectomy were randomized into either the Systemic group(n=7)or the Portal group(n=7).In the Systemic group,all pigs received temporal plasmapheresis(PP)via the extracorporeal catheter circuit(systemic to systemic circulation)from 24 to 30 h posthepatectomy(PH);in the Portal group,all pigs received ECPD to divert partial portal vein flow(PVF)to the systemic circulation after hepatectomy,then converted to temporal PP from 24 to 30 h PH,and subsequently converted to ECPD again until 48 h PH.In the Portal group,the PVF was preserved at 3.0-3.3 times that of the baseline value,similar to that following 70%hepatectomy,which was regarded as the optimal PVF to the hypertrophic liver remnant.At 48 h PH,all pigs were re-opened and the portal vein pressure(PVP),PVF,and HAF(hepatic artery flow)were measured,and then diversion of the portal venous flow was terminated.After1 h the PVP,PVF,and HAF were re-measured.The portal hemodynamic changes,liver injury,liver regeneration and bacterial/lipopolysaccharide(LPS)translocation were evaluated in the two groups.RESULTS:The PVP in the Portal group was significantly lower than that in the Systemic group during the time period from 2 to 49 h PH(P<0.05).Serum alanine aminotransferase(ALT),total bilirubin(TB)and ammonia were significantly reduced in the Portal group compared with the Systemic group from 24 to 48 h PH(P<0.05).The Portal group may have attenuated sinusoidal endothelial injury and decreased the level of HA compared with the Systemic group.In the Systemic group,there was significant sinusoidal dilation,hydropic changes in hepatocytes and hemorrhage into the hepatic parenchyma,and the sinusoidal endothelial lining was partially destroyed and detached into the sinusoidal space.CD31immunostaining revealed significant destruction of the endothelial lining.In the Portal group,there was no intraparenchymal hemorrhage and the sinusoidal endothelial cells and hepatocytes were well preserved.CD31immunostaining was mild which indicated less destruction of the endothelial lining.HA was significantly decreased in the Portal group compared with the Systemic group from 2 to 48 h PH.The rate of liver remnant regeneration was elevated,while apoptosis was attenuated in the Portal group compared with the Systemic group.Thymidine kinase activity was much higher in the Portal group than in the Systemic group at 48 h PH.The PCNA index was significantly increased and the apoptotic index was significantly decreased in the Portal group compared with the Systemic group.Bacterial translocation and endotoxin,as well as the inflammatory response,were significantly attenuated in the Portal group compared with the Systemic group.LPS,tumor necrosis factor-and interleukin-6 levels were all significantly decreased in the Portal group compared with the Systemic group from 24 to48 h PH,while bacterial DNA level was significantly decreased from 2 to 48 h PH.CONCLUSION:PP plus ECPD via the portal vein can attenuate toxic load and hyperperfusion injury,and should be undertaken instead of PP via the systemic circulation in SFSS or PLF.
基金Supported by National 863 High-Technology Research and Development Program,No.2012AA02A519
文摘AIM: To investigate the association between colorectal cancer(CRC) genetic susceptibility variants and esophageal cancer in a Chinese Han population.METHODS: A case-control study was conducted including 360 esophageal cancer patients and310 healthy controls. Thirty-one single-nucleotide polymorphisms(SNPs) associated with CRC risk from previous genome-wide association studies were analyzed. SNPs were genotyped using Sequenom Mass-ARRAY technology, and genotypic frequencies in controls were tested for departure from HardyWeinberg equilibrium using a Fisher's exact test. The allelic frequencies were compared between cases and controls using a χ 2 test. Associations between the SNPs and the risk of esophageal cancer were tested using various genetic models(codominant, dominant,recessive, overdominant, and additive). ORs and95%CIs were calculated by unconditional logistic regression with adjustments for age and sex.RESULTS: The minor alleles of rs1321311 and rs4444235 were associated with a 1.53-fold(95%CI:1.15-2.06; P = 0.004) and 1.28-fold(95%CI: 1.03-1.60;P = 0.028) increased risk of esophageal cancer in the allelic model analysis, respectively. In the genetic model analysis, the C/C genotype of rs3802842 was associated with a reduced risk of esophageal cancer in the codominant model(OR = 0.52, 95%CI:0.31-0.88; P = 0.033) and recessive model(OR =0.55, 95%CI: 0.34-0.87; P = 0.010). The rs4939827C/T-T/T genotype was associated with a 0.67-fold(95%CI: 0.46-0.98; P = 0.038) decreased esophageal cancer risk under the dominant model. In addition,rs6687758, rs1321311, and rs4444235 were associated with an increased risk. In particular, the T/T genotype of rs1321311 was associated with an 8.06-fold(95%CI: 1.96-33.07; P = 0.004) increased risk in the codominant model.CONCLUSION: These results provide evidence that known genetic variants associated with CRC risk confer risk for esophageal cancer, and may bring risk for other digestive system tumors.
基金supported by the National Key Research and Development Program of China(2016YFD0300102)supported by the Innovation Program of the Chinese Academy of Agricultural Sciences and the Elite Youth Program of the Chinese Academy of Agricultural Sciences。
文摘In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to increase maize yield in this area,because it increases topsoil temperature and moisture content as well as water use efficiency.However,the physiological and anatomical bases of maize yield improvement with plastic film mulching are not well understood.The effects of plastic film mulching and planting density on maize yield,photosynthetic characteristics,respiration,leaf anatomy,and root growth were studied in a two-year field experiment conducted on the Loess Plateau of China in 2017 and 2018.The experiment used a split-split plot design with two mulching treatments(plastic film mulching and no mulching),two planting densities(7.5×104 and10.5×104 plants ha-1),and two maize cultivars,Zhengdan 958 and Xianyu 335.Compared with no mulching,plastic film mulching increased maize yields by 31.1%–46.4%in 2017 and3.6%–34.7%in 2018.Compared with low planting density,high planting density significantly increased and slightly reduced yields of both cultivars in the dry year 2017 and the rainy year 2018,respectively.Plastic film mulching increased photosynthesis and respiration as well as leaf stomatal density and aperture.Photosynthetic rate,dark respiration,and stomatal conductance and aperture were lower at high planting than at low planting density.Maize yield was positively correlated with photosynthesis,dark respiration,and stomatal aperture.Mulching increased root dry weight and length in the 0–20 cm soil layer and root activity at maturity.Overall,the changes in root growth and leaf anatomy resulted in increased photosynthesis and dark respiration,and the increased photosynthesis contributed to the increase in grain yield and biomass production under plastic film mulching conditions.Our results increase understanding of the physiological mechanisms by which plastic film mulching increases maize yield in water-and temperature-limited areas.
文摘The appropriate fuze-warhead coordination method is important to improve the damage efficiency of air defense missiles against aircraft targets. In this paper, an adaptive fuze-warhead coordination method based on the Back Propagation Artificial Neural Network(BP-ANN) is proposed, which uses the parameters of missile-target intersection to adaptively calculate the initiation delay. The damage probabilities at different radial locations along the same shot line of a given intersection situation are calculated, so as to determine the optimal detonation position. On this basis, the BP-ANN model is used to describe the complex and highly nonlinear relationship between different intersection parameters and the corresponding optimal detonating point position. In the actual terminal engagement process, the fuze initiation delay is quickly determined by the constructed BP-ANN model combined with the missiletarget intersection parameters. The method is validated in the case of the single-shot damage probability evaluation. Comparing with other fuze-warhead coordination methods, the proposed method can produce higher single-shot damage probability under various intersection conditions, while the fuzewarhead coordination effect is less influenced by the location of the aim point.
基金the National Basic Research Program of China (973-2015CB150400)the National Institute of Food and Agriculture (ALA014-1-16016)U.S. Department of Agriculture,Hatch project under ALA014-1-16016
文摘Accurate leaf area simulation is critical for the performance of crop growth models. Area of fully expanded individual leaves of maize hybrids released before 1995 (defined as old hybrids) has been simulated using a bell-shaped function (BSF) and the relationship between its parameters and total leaf number (TLNO). However, modern high-yielding maize hybrids show different canopy architectures. The function parameters calibrated for old hybrids will not accurately represent modern hybrids. In this study, we evaluated these functions using a dataset including old and modern hybrids that have been widely planted in China in recent years. Maximum individual leaf area (Y_0) and corresponding leaf position (X_0) were not predicted well by TLNO (R^2= 0.56 and R^2= 0.70) for modern hybrids. Using recalibrated shape parameters a and b with values of Y_0 and X_0 for modern hybrids, the BSF accurately predicted individual leaf area (R^2= 0.95–0.99) and total leaf area of modern hybrids (R^2= 0.98). The results show that the BSF is still a robust way to predict the fully expanded leaf area of maize when parameters a and b are modified and Y_0 and X_0 are fitted. Breeding programs have led to increases in TLNO of maize but have not altered Y_0 and X_0, reducing the correlation between Y_0, X_0, and TLNO. For modern hybrids, the values of Y_0 and X_0 are hybrid-specific. Modern hybrids tend to have less-negative values of parameter a and more-positive values of parameter b in the leaf profile. Growth conditions, such as plant density and environmental conditions, also affect the fully expanded leaf area but were not considered in the original published equations. Thus, further research is needed to accurately estimate values of Y_0 and X_0 of individual modern hybrids to improve simulation of maize leaf area in crop growth models.
基金financially supported by the Natural Science Foundation of China(No.51571142)the National Key Research and Development Program of China(No.2018YFC1106600)。
文摘Magnesium(Mg)is a promising biomedical metal because of its biodegradability.The crevice between tissue and Mg implant can not be neglected in some implantation sites due to inducing crevice corrosion of Mg.In this paper,a new single mold was designed to build the in vitro experimental setup and four kinds of solutions,i.e.the deionized water(DW),the 0.9 wt.%sodium chloride solution(NaCl),the phosphate buffer saline(PBS)and the modified simulated body fluid(m-SBF)were used to explore necessary factors of crevice corrosion in Mg.It was observed that crevice corrosion in Mg sheets would occur in NaCl and PBS solution under 0.2,0.5 and 0.8 mm crevice thickness.And it was found that there were two necessary factors,i.e.chloride ion and crevice dimension,in crevice corrosion.For the high-purity Mg cannulated screws,crevice corrosion could occur inside tunnel when immersed in PBS.
基金Sponsored by the Military Commission on Science and Technology(Grant No.17-163-18-XJ-001-054-01)
文摘To solve the special requirements of the high orbit optical remote sensing satellite for the thermal deformation of the platform the thermal deformation test and measurement scheme of the satellite platform is designed. Through the comparative analysis of test results the rationality of the thermal deformation design of the platform structure is verified. The results of thermal deformation measurement show that the maximum deformation of A camera mounting surface is 57.5〃 and the maximum deformation of B camera mounting surface points to 79.3〃 which can be used as the basis for thermal deformation prediction of satellite during the orbit operation.
基金partly funded by the National Natural Science Foundation of China (31272279, 31970443)the Liaoning Provincial Natural Science Foundation (2022-BS-332)the Ministry of Science and Technology of the People’s Republic of China (2005DKA21402)。
基金supported by The Fundamental Research Funds for the Central Universities,China。
文摘The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft targets.In this paper,three missile terminal attitude selection methods are proposed to solve the problem of terminal attitude selection in different situations according to their respective evaluation indexes.The MVE-based method uses the damage probability of each detonation point around the aircraft at a given attitude of missile to calculate the Mean Volume of Effectiveness(MVE)at the corresponding attitude,and then uses the MVE for different attitudes to select the terminal strike attitude.The detonation position-based method addresses the case where the missile detonation position can be assessed in advance.Given the effects of missile guidance errors and fuze activation position errors,Monte Carlo simulations are used to calculate the damage probability of aircraft with different strike attitudes,from which the terminal strike attitude is selected.The BP-ANN model-based method uses the constructed Back Propagation Artificial Neural Network(BP-ANN)model instead of simulation to calculate the evaluation indexes in the corresponding cases of MVE-based method and Detonation position-based method,which can improve the efficiency of attitude selection.Simulations are conducted for different scenarios to verify the feasibility and effectiveness of the proposed method.
基金supported by PVST project, funded under the Danish Energiteknologiske Udviklings-og Demonstrationsprogram (EUDP) programme (64017-0041)the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (LAPS21)
文摘The decreasing cost of solar photovoltaics(PVs)and battery storage systems is driving their adoption in the residential distribution system,where more consumers are becoming prosumers.Accompanying this trend is the potential roll-out of home energy management systems(HEMSs),which provide a means for prosumers to respond to externalities such as energy price,weather,and energy demands.However,the economic operation of prosumers can affect grid security,especially when energy prices are extremely low or high.Therefore,it is paramount to design a framework that can accommodate the interests of the key stakeholders in distribution systems—namely,the network operator,prosumer,and aggregator.In this paper,a novel transactive energy(TE)-based operational framework is proposed.Under this frame-work,aggregators interact with the distribution grid operator through a negotiation process to ensure network security,while at the lower level,prosumers submit their schedule to the aggregator through the HEMS.If network security is at risk,aggregators will send an additional price component representing the cost of security(CoS)to the prosumer to stimulate further response.The simulation results show that the proposed framework can effectively ensure the economic operation of aggregators and prosumers in distribution systems while maintaining grid security.
基金financially supported by the National Natural Science Foundation of China(No.60571032,60121101)the Trans-Century Training Programme Foundation for the Talents by the Ministry of Education of China(2003)+1 种基金the Doctoral Program of Higher Education for funding(20050286014)the Natural Science Foundation of Guangdong,Province,China(No.04008782).
文摘High-throughput SNP detection microarrays were used here to explore the relationship between 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T and the risk of gastric carcinoma among population in Jiangsu region,by genotyping the specimens from 170 patients with gastric carcinoma and 140 age-and sex- matched control subjects.PCR products were spotted onto a 3-aminopropyltriethoxysilane coated glass slide to fabricate a microarray,then interrogated by hybridization with dual-color probes (Cy3,CyS) to determine the SNP genotype of each sample,and the relation between the genotypes and the risk of gastric carcinoma was analyzed.The frequencies of C677T genotype were CC(47.9%),CT(40%),CT(12.1%) in control group and CC(35.9%),CT(45.9%),TT(18.2%) in gastric carcinoma group,respectively.The individuals with 677CT+TT genotype group or 677TT had a 1.67-fold (95% CI:1.06-2.64) or 2.67-fold (95% CI:1.382-5.341) increased risk to develop gastric carcinoma compared with those having 677CC genotype. It was shown that the single nucleotide polymorphisms in the MTHFR gene are associated with the risk of gastric carcinoma in the Chinese population.
