BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly dec...BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly declined,leaving a large number of patients with previous treatment histories.AIM To investigate secondary resistance rates,explore risk factors for antibiotic resistance,and assess the efficacy of susceptibility-guided therapy.METHODS We recruited 154 subjects positive for Urea Breath Test who attended The First Affiliated Hospital of China Medical University between July 2022 and April 2023.Participants underwent a string test after an overnight fast.The gastric juice was obtained and transferred to vials containing storage solution.Subsequently,DNA extraction and the specific DNA amplification were performed using quantitative polymerase chain reaction(qPCR).Demographic information was also analyzed as part of the study.Based on these results,the participants were administered susceptibility-guided treatment.Efficacy was compared with that of the empiric treatment group.RESULTS A total of 132 individuals tested positive for the H.pylori ureA gene by qPCR technique.CLA resistance rate reached a high level of 82.6%(n=109),LFX resistance rate was 69.7%(n=92)and dual resistance was 62.1%(n=82).Gastric symptoms[odds ratio(OR)=2.782;95%confidence interval(95%CI):1.076-7.194;P=0.035]and rural residence(OR=5.152;95%CI:1.407-18.861;P=0.013)were independent risk factors for secondary resistance to CLA and LFX,respectively.A total of 102 and 100 individuals received susceptibility-guided therapies and empiric treatment,respectively.The antibiotic susceptibility-guided treatment and empiric treatment groups achieved successful eradication rates of 75.5%(77/102)and 59.0%(59/411)by the intention-to-treat(ITT)analysis and 90.6%(77/85)and 70.2%(59/84)by the per-protocol(PP)analysis,respectively.The eradication rates of these two treatment strategies were significantly different in both ITT(P=0.001)and PP(P=0.012)analyses.CONCLUSION H.pylori presented high secondary resistance rates to CLA and LFX.For patients with previous treatment failures,treatments should be guided by antibiotic susceptibility tests or regional antibiotic resistance profile.展开更多
Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performa...Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performance is severely affected at high temperatures.Drag reducing agent is the key to determine the drag reducing performance of slickwater.In this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant slickwater.The slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and evaluated.In contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ability.Notably,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing period.Additionally,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.展开更多
Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,ligni...Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant density.We compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.The optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin content.The application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.Internode diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging percentage.In conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.展开更多
In the last decades,vanadium alloyed coatings have been introduced as potential candidates for self-lubrication due to their perfect tribological properties.In this work,the influence of V incorporation on the wear pe...In the last decades,vanadium alloyed coatings have been introduced as potential candidates for self-lubrication due to their perfect tribological properties.In this work,the influence of V incorporation on the wear performance and oxidation resistance of TiSiN/CrN film coatings deposited by direct current(DC)reactive magnetron sputtering is investigated.The results show that vanadium incorporation significantly decreases the oxidation resistance of the coatings.In general,two layers are formed during the oxidation process:i)Ti(V)O_(2) on top,followed by a protective layer,which is subdivided into two layers,Cr_(2)O_(3) and Si-O.ii)The diffusion of V controls the oxidation of V-containing coatings.The addition of vanadium improves the wear resistance of coatings,and the wear rate decreases with increasing V content in the coatings;however,the friction coefficient is independent of the chemical composition of the coatings.The wear of the V-containing coatings is driven by polishing wear.展开更多
Mg?1Zn?0.5Ca alloys were prepared by traditional steel mould casting and water-cooled copper mould injection casting at higher cooling rate. Microstructure, mechanical properties and bio-corrosion resistance of two al...Mg?1Zn?0.5Ca alloys were prepared by traditional steel mould casting and water-cooled copper mould injection casting at higher cooling rate. Microstructure, mechanical properties and bio-corrosion resistance of two alloys were contrastively investigated. Grain size reduces remarkably and microstructure becomes homogenous when raising cooling rate. The bio-corrosion behaviour in 3.5% sodium chloride solution (3.5% NaCl) and Hank’s solution at 37°C was investigated using electrochemical polarization measurement and the results indicate that the alloy prepared at higher cooling rates has better corrosion resistance in both types of solution. Further mass loss immersion test in Hank’s solution reveals the same result. The reason of corrosion resistance improvement is that raising cooling rate brings about homogeneous microstructure, which leads to micro-galvanic corrosion alleviation. The tensile test results show that yield strength, ultimate tensile strength and elongation are improved by raising cooling rate and the improvement is mainly due to grain refinement.展开更多
The function of serrate(SE)in miRNA biogenesis in Arabidopsis is well elucidated,whereas its role in plant drought resistance is largely unknown.In this study,we report that MdSE acts as a negative regulator of apple(...The function of serrate(SE)in miRNA biogenesis in Arabidopsis is well elucidated,whereas its role in plant drought resistance is largely unknown.In this study,we report that MdSE acts as a negative regulator of apple(Malus×domestica)drought resistance by regulating the expression levels of MdMYB88 and MdMYB124 and miRNAs,including mdm-miR156,mdm-miR166,mdm-miR172,mdm-miR319,and mdm-miR399.MdSE interacts with MdMYB88 and MdMYB124,two positive regulators of apple drought resistance.MdSE decreases the transcript and protein levels of MdMYB88 and MdMYB124,which directly regulate the expression of MdNCED3,a key enzyme in abscisic acid(ABA)biosynthesis.Furthermore,MdSE is enriched in the same region of the MdNECD3 promoter where MdMYB88/MdMYB124 binds.Consistently,MdSE RNAi transgenic plants are more sensitive to ABA-induced stomatal closure,whereas MdSE OE plants are less sensitive.In addition,under drought stress,MdSE is responsible for the biogenesis of mdm-miR399,a negative regulator of drought resistance,and negatively regulates miRNAs,including mdm-miR156,mdm-miR166,mdm-miR172,and mdm-miR319,which are positive regulators of drought resistance.Taken together,by revealing the negative role of MdSE,our results broaden our understanding of the apple drought response and provide a candidate gene for apple drought improvement through molecular breeding.展开更多
This study explores the efficacy of advanced antibiotic compounds against P. aeruginosa, focusing on Antibiotic B, an enhanced derivative of Ceftriaxone. The study measured the intracellular uptake of Antibiotic B and...This study explores the efficacy of advanced antibiotic compounds against P. aeruginosa, focusing on Antibiotic B, an enhanced derivative of Ceftriaxone. The study measured the intracellular uptake of Antibiotic B and introduced a novel adjuvant, Influximax, which augmented its antibacterial activity. Results showed a diminished potential for resistance emergence with Antibiotic B, particularly when used in combination with Influximax. The study suggests that optimizing antibiotic delivery into bacterial cells and leveraging syner-gistic adjuvant combinations can enhance drug resistance combat. .展开更多
Magnesium alloy is one of the most widely used lightweight structural materials,and the development of high strength-toughness magnesium alloy is an important research field at present and even in the future.The prepa...Magnesium alloy is one of the most widely used lightweight structural materials,and the development of high strength-toughness magnesium alloy is an important research field at present and even in the future.The preparation process parameters of magnesium alloy directly affect the microstructure of the magnesium alloy,and then determine the properties of the magnesium alloy.The cooling rate has important effects on the microstructure and properties of the magnesium alloy,and is an important preparation process parameter that cannot be ignored.Both the cooling rate from liquid phase to solid phase and the cooling rate of the magnesium alloy after heat treatment will change the microstructure of the magnesium alloy.Furthermore,the properties of magnesium alloy will be affected.In this paper,the effects of cooling rate on the solidification behavior,the rheological behavior,the change of microstructure(the solid solution of alloying elements in matrix,the composition,size,distribution and morphology of second phase,the diffusion and segregation of alloying elements,the grain size,the formation and morphology of dendrite,etc.),and the effects of cooling rate of magnesium alloy after heat treatment on the microstructure and stress distribution are reviewed.The reasons for the divergence about the influence of cooling rate on the microstructure of magnesium alloy are analyzed in detail.The effects of cooling rate on the mechanical properties,corrosion resistance and oxidation resistance of magnesium alloy are also analyzed and discussed deeply.Finally,the new methods and approaches to study the effects of cooling rate on the microstructure and properties of magnesium alloy are prospected.展开更多
The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of pro...The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of properties. The results show that for the cast steel after deformed, the amount of granular carbides of precipitation during the cooling decreased with the increase of the cooling rate, but the hardness was obviously enhanced, as a result, better mechanical properties will be obtained by force air cooling(cooling rate is about 7 ℃·s-1). And the reason of the change for structure and mechanical properties of the cast steel were analyzed.展开更多
Helicobacter pylori (H. pylori) eradication rates achieved with a proton pump inhibitor (PPI), amoxicillin and clarithromycin have recently decreased to about 75% because of the increase in clarithromycin resistance i...Helicobacter pylori (H. pylori) eradication rates achieved with a proton pump inhibitor (PPI), amoxicillin and clarithromycin have recently decreased to about 75% because of the increase in clarithromycin resistance in Japan. In the present study, H. pylori resistance rates against clarithromycin, amoxicillin and metronidazole were investigated in pediatric patients and eradication rates were evaluated when tailored antibiotics regimens based on antibiotic sensitivity data were used. We isolated H. pylori endoscopically from 77 pediatric patients suffering from abdominal symptoms. The susceptibility tests of H. pylori strains to clarithromycin, amoxicillin and metronidazole were examined and eradication therapy was tailored using the appropriate antibiotics. Seventy-seven patients were treated with a mean age of 12.16 ± 3.34 years (range, 4.92-19.75) consisting of 40 males and 37 females. The average resistance rates between 1998 and 2016 to clarithromycin, amoxicillin and metronidazole were 54.5% (42 of 77), 6.5% (5 of 77) and 5.2% (4 of 77) respectively. The prevalence of clarithromycin resistance increased significantly over time to reach 88.9% by 2013-2016. Successful eradication rates using tailored antibiotic treatment was 93.8% (61 of 65). Clarithromycin-based eradication therapy rate reached 92.6% against clarithromycin-sensitive strains. Metronidazole-based initial eradication therapy also had a high successful rate (97.0%) to clarithromycin-resistant strains. Although high rates of clarithromycin resistant H. pylori reaching about 90% were observed in Japanese children, tailored eradication therapy using the appropriate antibiotic agents were highly successful. H. pylori sensitivity testing and eradication therapy with appropriate antibacterial agents may contribute to accomplishment of high initial eradication rates and consequently reducing the incidence of developing gastric cancer.展开更多
2195 aluminum-lithium alloy was widely applied in the aviation and aerospace industry, but it is highly susceptible to pitting and intergranular corrosion undergoing sever corrosive circumstance and moisture atmospher...2195 aluminum-lithium alloy was widely applied in the aviation and aerospace industry, but it is highly susceptible to pitting and intergranular corrosion undergoing sever corrosive circumstance and moisture atmosphere. To solve this problem and consequently to prolong its service life, a multi-step-heating-rate(MSRC) process was carried out. Investigations were carried out to find the effect of the MSRC process on the alloys corrosion resistance. It is found that the MSRC process is more favorable for the uniform phase precipitation by comparing the corrosion resistance of samples treated by traditional heat treatments. The potential difference between phases can be reduced and intergranular corrosion is able to be prohibited efficiently. Besides, the rare earth infiltration is beneficial to improving the corrosion resistance. As heating time increases, the corrosion resistance declines gradually, samples treated by artificial aging and solid solution also exhibit a better corrosion resistance.展开更多
Mg-Gd-Y-Zr alloys were purified by filtering purification with and without vacuum. The type, morphology, size distribution and volume fraction of inclusion were analyzed with OM and SEM. The effect of inclusion in Mg-...Mg-Gd-Y-Zr alloys were purified by filtering purification with and without vacuum. The type, morphology, size distribution and volume fraction of inclusion were analyzed with OM and SEM. The effect of inclusion in Mg-Gd-Y-Zr alloys on anticorrosion ability was investigated with salt spray test and electrochemical test. The results show that the inclusions in the alloy can be removed effectively by filtering purification. The average size of inclusions in the alloys is decreased from 12.7 μm to 2.0 μm and the volume fraction of inclusions is reduced from 0.30% to 0.04%. With the decrease of the size of inclusions in the alloys, the corrosion rate of the alloys decreases dramatically from 38.8 g/(m 2 ·d) to 2.4 g/(m 2 ·d) in the salt spray test. The corrosion potential increases while the corrosion current decreases and the polarization resistance increases in the electrochemical tests, which indicates that the anticorrosion ability is improved.展开更多
xCu/(10NiO-NiFe2O4) cermet and 1BaO-xCu/(10NiO-NiFe2O4) cermet(x=5,10,17) inert anodes were prepared as potential inert anodes for aluminum electrolysis and their corrosion resistance to traditional electrolyte ...xCu/(10NiO-NiFe2O4) cermet and 1BaO-xCu/(10NiO-NiFe2O4) cermet(x=5,10,17) inert anodes were prepared as potential inert anodes for aluminum electrolysis and their corrosion resistance to traditional electrolyte was studied with anodic current density of 1.0 A/cm2 in laboratory electrolysis.The substantial corrosion of metal Cu was observed,many pores appeared on the surface of anode and electrolytes infiltrated inside anodes during the electrolysis.The wear rates of 5Cu/(10NiO-NiFe2O4),10Cu/(10NiO-NiFe2O4),17Cu/(10NiO-NiFe2O4),1BaO-5Cu/(10NiO-NiFe2O4),1BaO-10Cu/(10NiO-NiFe2O4) and 1BaO-17Cu/(10NiO-NiFe2O4) are 2.15,6.50,8.30,4.88,4.70 and 4.48 cm/a,respectively.The addition of BaO to 10Cu/(10NiO-NiFe2O4) cermet and 17Cu/(10NiO-NiFe2O4) cermet is advantageous because BaO can effectively promote densification and thus improve corrosion resistance.But the addition of BaO to 5Cu/(10NiO-NiFe2O4) cermet is unfavorable to corrosion resistance because additive BaO at the grain boundary of anode accelerates possibly the corrosion of cermet.展开更多
The influence of chemical composition on corrosion resistance of AZ91D magnesium alloys ingots has been investigated. Mass loss method was applied to evaluate the corrosion resistance of AZ91D alloys and the data were...The influence of chemical composition on corrosion resistance of AZ91D magnesium alloys ingots has been investigated. Mass loss method was applied to evaluate the corrosion resistance of AZ91D alloys and the data were analyzed by multiple regression. The results show that the corrosion resistance of this alloy can be improved by increasing Al, Zn and Mn in a certain degree, and will drop with increasing Si and heavy metals (Fe, Cu, Ni). It is found that ingots received from company F should be listed into unusable materials in terms of the corrosion resistance, while among the five suppliers, the only local company E supplied excellent AZ91D magnesium alloy ingots with the best corrosion resistance.展开更多
To evaluate the efficacy of antimicrobial susceptibility-guided therapy before first-line treatment for infection in patients with dual or triple antibiotic resistance.METHODSA total of 1034 patients infected by Helic...To evaluate the efficacy of antimicrobial susceptibility-guided therapy before first-line treatment for infection in patients with dual or triple antibiotic resistance.METHODSA total of 1034 patients infected by Helicobacter pylori (H. pylori) during 2013-2014 were tested for antimicrobial susceptibility. 157 of 1034 (15%) patients showed resistance to two (127/1034; 12%) and to three (30/1034; 3%) antibiotics. Sixty-eight patients with dual H. pylori-resistance (clarithromycin, metronidazole or levofloxacin) were treated for 10 d with triple therapies: OAL (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and levofloxacin 500 mg b.i.d.) 43 cases, OAM (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and metronidazole 500 mg b.i.d.) 12 cases and OAC (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and clarithromycin 500 mg b.i.d.) 13 cases based on the antimicrobial susceptibility testing. Twelve patients showed triple H. pylori-resistance (clarithromycin, metronidazole and levofloxacin) and received for 10 d triple therapy with OAR (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and rifabutin 150 mg b.i.d.). Eradication was confirmed by 13C-urea breath test. Adverse effects and compliance were assessed by a questionnaire.RESULTSIntention-to-treat eradication rates were: OAL (97.6%), OAM (91.6%), OAC (92.3%) and OAR (58.3%). Cure rate was significantly higher in naïve patients treated with OAR-10 compared to patients who had two or three previous treatment failures (83% vs 33%). Adverse events rates for OAL, OAM, OAC and OAR were 22%, 25%, 23% and 17%, respectively, all of them mild-moderate.CONCLUSIONAntimicrobial susceptibility-guided triple therapies during 10 d for first-line treatment leads to an eradication rate superior to 90% in patients with dual antibiotic H. pylori resistance.展开更多
Objective: To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods: Pathogenic...Objective: To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods: Pathogenic bacteria identification and drug sensitivity tests were performed with a VITEK 2 compact automatic identification system and data were analyzed using WHONET5.6 software.Results: Of the 1,378 strains tested, 980 were Gram-negative bacilli, accounting for 71.1%, in which Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa were the dominant strains. We found 328 Gram-positive coccus, accounting for 23.8%, in which the amount of Staphylococcus aureus was the highest. We identified 46 fungi, accounting for 4.1%. According to the departmental distribution within the hospital, the surgical departments isolated the major strains, accounting for 49.7%. According to disease types, lung cancer, intestinal cancer and esophagus cancer were the top three, accounting for 20.9%, 17.3% and 14.2%, respectively. No strains were resistant to imipenem, ertapenem or vancomycin.Conclusions: Pathogenic bacteria isolated from the specialized cancer hospital have different resistance rates compared to commonly used antimicrobial agents; therefore antimicrobial agents to reduce the morbidity and mortality of infections should be used.展开更多
To identify the major factors that contribute to the difference in lodging among different rice varieties under machine transplanting and their responses to nitrogen(N),field experiments were conducted at Danyang Coun...To identify the major factors that contribute to the difference in lodging among different rice varieties under machine transplanting and their responses to nitrogen(N),field experiments were conducted at Danyang County(a representative eco-site of the Lower Yangtze River)in Jiangsu Province,China in 2017 and 2018,22 hybrid indica varieties(HIs),22 inbred japonica varieties(IJs)and two indica japonica hybrid varieties(IJHs)were transplanted by machine with three N rates(N0,N150 and N300,0,150 and 300 kg ha–1,respectively).Lodging-related physical parameters,morphological characteristics and apparent transport rates of dry matter were examined.Significant difference in yield was observed among different types of rice,and followed by IJs<HIs<IJHs.The average lodging index(LI)of hybrid varieties(HIs and IJHs)was higher than that of the inbred varieties(IJs)with higher plant height;moreover,lower apparent export rate of dry matter resulted lower LI in IJHs than in HIs.The HIs had a large difference in the LI,which came from the difference in bending stress(BS)induced by the difference in the apparent export rate of dry matter,varieties with lower leaf angle of upper three leaves possess strong lodging resistance capacity;however,the gap among the IJs was due to the difference in the cross section modulus(Z).The LI in the IJs or IJHs increased slightly with the increased N application,and there was no lodging incidence under the high N level,which was due to the low leaf angle and barely changed under high N;there was a significant interaction between varieties(HIs)and N rates in lodging rate and LI,varieties with lower leaf angle of upper three leaves were resistant to high N.These results suggest that compact plant type rice has higher lodging and N resistance at machine-transplanting method.展开更多
To improve the crack-resistance of the mould for silica sol bonded quartz based ceramic mould casting,aluminum silicate fibers with the diameter ranging from 5 μm to 25 μm and the length about 1 mm were dispersed in...To improve the crack-resistance of the mould for silica sol bonded quartz based ceramic mould casting,aluminum silicate fibers with the diameter ranging from 5 μm to 25 μm and the length about 1 mm were dispersed in the ceramic mould.The effect of the aluminum silicate fibers on the tensile strength,shrinkage rate and the cracking trend of the ceramic mould were investigated.In the ceramic slurry,quartz sand was applied as ceramic aggregate,silica sol containing 30% silicon dioxide as bonder,and the weight ratio of quartz sand to silica sol was 2.69;the dispersed fibers changed from 0 to 0.24vol.%.The mould samples were formed after the slurry was poured and gelled at room temperature,and then sintered at different temperatures ranging from 100 to 800 ℃ to measure the tensile strength and shrinkage rate.The results show that,with the aluminum silicate fiber addition increasing from 0 to 0.24vol.%,the tensile strength increases linearly from 0.175 MPa to 0.236 MPa,and the shrinkage rate decreases linearly from 1.75% to 1.68% for the ceramic mould sintered at 400 ℃,from 1.37% to 1.31% for the ceramic mould at room temperature.As the sintering temperature was raised from 100 ℃ to 800 ℃,the tensile strength increases,and the shrinkage rate decreases at all temperatures,compared with those without fiber dispersion,but their variation patterns remain the same.Furthermore,the cracking trend of the mould and its decreasing proportion were defined and analyzed quantitatively considering both effects of the fiber dispersion on the strength and shrinkage.The cracking trend appears to decrease linearly with increasing fiber content and to reach the maximum reduction of 28.8% when 0.24vol.% fiber was dispersed.Therefore,the investigation proposes a new method to improve the crack-resistance of the ceramic mould,i.e.,inorganic fiber dispersion into the ceramic mould.展开更多
Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification st...Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.展开更多
In this study, the plant biomass production, biomass translocation rates across tissues and the lodging resistant-associated traits of millet ( Setaria italica L.) in North China were investigated. Among the four su...In this study, the plant biomass production, biomass translocation rates across tissues and the lodging resistant-associated traits of millet ( Setaria italica L.) in North China were investigated. Among the four summer millet cultivars, Baogu 19 exhibited improved plant biomass (PB) production at flowering and maturity stages, biomass translocation amount (BTA) from vegetative tissues to seeds during filling period, and lodging resistant-associated (LRA) traits compared with other cultivars, including enhanced stem lignin contents, increased anti-broken resistance (ABR), anti-puncturing resistance (APR), and stem diameter (SD) of plants. Compared with treatment regular cultivation (RC), high fertility treatment (HF) increased the plant BP, BTA from vegetative tissue to seed at filling stage, and the plant LRA traits; whereas high density treatment (HD) decreased the plant BP at plant level, plant BTA from vegetative tissues to seeds at filling stage, and the plant LRA traits. Correlation analysis revealed that stem ABR is significantly correlated with the plant lodging resistant-associated traits including APR and SD in the summer millet cultivars examined under various cultivation treatments. Our investigation indicates that cultivar Baogu 19 together with suitable fertilization and density can promote the plant biomass production, enhance vegetative tissue biomass translocation to seeds, and improve the lodging resistance of summer millet plants in North China.展开更多
基金The study was reviewed and approved by the the Human Ethics Review Committee of the First Affiliated Hospital of China Medical University(Approval No.2021325).
文摘BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly declined,leaving a large number of patients with previous treatment histories.AIM To investigate secondary resistance rates,explore risk factors for antibiotic resistance,and assess the efficacy of susceptibility-guided therapy.METHODS We recruited 154 subjects positive for Urea Breath Test who attended The First Affiliated Hospital of China Medical University between July 2022 and April 2023.Participants underwent a string test after an overnight fast.The gastric juice was obtained and transferred to vials containing storage solution.Subsequently,DNA extraction and the specific DNA amplification were performed using quantitative polymerase chain reaction(qPCR).Demographic information was also analyzed as part of the study.Based on these results,the participants were administered susceptibility-guided treatment.Efficacy was compared with that of the empiric treatment group.RESULTS A total of 132 individuals tested positive for the H.pylori ureA gene by qPCR technique.CLA resistance rate reached a high level of 82.6%(n=109),LFX resistance rate was 69.7%(n=92)and dual resistance was 62.1%(n=82).Gastric symptoms[odds ratio(OR)=2.782;95%confidence interval(95%CI):1.076-7.194;P=0.035]and rural residence(OR=5.152;95%CI:1.407-18.861;P=0.013)were independent risk factors for secondary resistance to CLA and LFX,respectively.A total of 102 and 100 individuals received susceptibility-guided therapies and empiric treatment,respectively.The antibiotic susceptibility-guided treatment and empiric treatment groups achieved successful eradication rates of 75.5%(77/102)and 59.0%(59/411)by the intention-to-treat(ITT)analysis and 90.6%(77/85)and 70.2%(59/84)by the per-protocol(PP)analysis,respectively.The eradication rates of these two treatment strategies were significantly different in both ITT(P=0.001)and PP(P=0.012)analyses.CONCLUSION H.pylori presented high secondary resistance rates to CLA and LFX.For patients with previous treatment failures,treatments should be guided by antibiotic susceptibility tests or regional antibiotic resistance profile.
基金supported by the National Natural Science Foundation of China(Nos.52222403,52074333,52120105007)Taishan Scholar Young Expert(No.tsqn202211079)。
文摘Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performance is severely affected at high temperatures.Drag reducing agent is the key to determine the drag reducing performance of slickwater.In this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant slickwater.The slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and evaluated.In contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ability.Notably,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing period.Additionally,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.
基金supported by projects funded by the China Postdoctoral Science Foundation(2019M663837 and 2021M701521)the National High-Tech Research and Development Programs of China(2013AA102902)the special fund for Agro-scientific Research in the Public Interest,China(201303104)。
文摘Lodging in maize leads to yield losses worldwide.In this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant density.We compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.The optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin content.The application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging percentage.Internode diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging percentage.In conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.
基金financially supported by the National Natural Science Foundation of China(Nos.51801081 and 52171071)national funds through FCT of Portugal-Fundacao para a Ciencia e a Tecnologia,under a scientific contract of 2021.04115,CEMMPRE-ref.“UIDB/00285/2020”and LA/P/0112/2020 projects+2 种基金FEDER funds through the COMPETE program-Operational Program on Competitiveness Factorsnational funds through FCT-Foundation for Science and Technology,Outstanding University Young Teachers of“Qing Lan Project”of Jiangsu Province of China,Excellent Talents of“Shenlan Project”of Jiangsu University of Science and Technology of ChinaA part of this study was supported by the Directorate-General of Scientific Research and Technological Development(Algeria)。
文摘In the last decades,vanadium alloyed coatings have been introduced as potential candidates for self-lubrication due to their perfect tribological properties.In this work,the influence of V incorporation on the wear performance and oxidation resistance of TiSiN/CrN film coatings deposited by direct current(DC)reactive magnetron sputtering is investigated.The results show that vanadium incorporation significantly decreases the oxidation resistance of the coatings.In general,two layers are formed during the oxidation process:i)Ti(V)O_(2) on top,followed by a protective layer,which is subdivided into two layers,Cr_(2)O_(3) and Si-O.ii)The diffusion of V controls the oxidation of V-containing coatings.The addition of vanadium improves the wear resistance of coatings,and the wear rate decreases with increasing V content in the coatings;however,the friction coefficient is independent of the chemical composition of the coatings.The wear of the V-containing coatings is driven by polishing wear.
基金Project(20921002)supported by the Innovative Research Groups of the National Natural Science Foundation of ChinaProject(21221061)supported by the National Natural Science Foundation of China+1 种基金Project(201105007)supported by the Science and Technology Program of Jilin Province,ChinaProject(20140325003GX)supported by the Science and Technology Support Project of Jilin Province,China
文摘Mg?1Zn?0.5Ca alloys were prepared by traditional steel mould casting and water-cooled copper mould injection casting at higher cooling rate. Microstructure, mechanical properties and bio-corrosion resistance of two alloys were contrastively investigated. Grain size reduces remarkably and microstructure becomes homogenous when raising cooling rate. The bio-corrosion behaviour in 3.5% sodium chloride solution (3.5% NaCl) and Hank’s solution at 37°C was investigated using electrochemical polarization measurement and the results indicate that the alloy prepared at higher cooling rates has better corrosion resistance in both types of solution. Further mass loss immersion test in Hank’s solution reveals the same result. The reason of corrosion resistance improvement is that raising cooling rate brings about homogeneous microstructure, which leads to micro-galvanic corrosion alleviation. The tensile test results show that yield strength, ultimate tensile strength and elongation are improved by raising cooling rate and the improvement is mainly due to grain refinement.
基金supported by the National Key Research and Development Program of China(2019YFD1000100)the National Natural Science Foundation of China(31622049 and 31872080).
文摘The function of serrate(SE)in miRNA biogenesis in Arabidopsis is well elucidated,whereas its role in plant drought resistance is largely unknown.In this study,we report that MdSE acts as a negative regulator of apple(Malus×domestica)drought resistance by regulating the expression levels of MdMYB88 and MdMYB124 and miRNAs,including mdm-miR156,mdm-miR166,mdm-miR172,mdm-miR319,and mdm-miR399.MdSE interacts with MdMYB88 and MdMYB124,two positive regulators of apple drought resistance.MdSE decreases the transcript and protein levels of MdMYB88 and MdMYB124,which directly regulate the expression of MdNCED3,a key enzyme in abscisic acid(ABA)biosynthesis.Furthermore,MdSE is enriched in the same region of the MdNECD3 promoter where MdMYB88/MdMYB124 binds.Consistently,MdSE RNAi transgenic plants are more sensitive to ABA-induced stomatal closure,whereas MdSE OE plants are less sensitive.In addition,under drought stress,MdSE is responsible for the biogenesis of mdm-miR399,a negative regulator of drought resistance,and negatively regulates miRNAs,including mdm-miR156,mdm-miR166,mdm-miR172,and mdm-miR319,which are positive regulators of drought resistance.Taken together,by revealing the negative role of MdSE,our results broaden our understanding of the apple drought response and provide a candidate gene for apple drought improvement through molecular breeding.
文摘This study explores the efficacy of advanced antibiotic compounds against P. aeruginosa, focusing on Antibiotic B, an enhanced derivative of Ceftriaxone. The study measured the intracellular uptake of Antibiotic B and introduced a novel adjuvant, Influximax, which augmented its antibacterial activity. Results showed a diminished potential for resistance emergence with Antibiotic B, particularly when used in combination with Influximax. The study suggests that optimizing antibiotic delivery into bacterial cells and leveraging syner-gistic adjuvant combinations can enhance drug resistance combat. .
基金supports from the Natural Science Foundation of Inner Mongolia Autonomous Region of china(2024MS05009)National Natural Science Foundation of China(51661025)+1 种基金Research Program of science and technology at Universities of Inner Mongolia Autonomous Region(NJZY21315)Scientific research project of Inner Mongolia University of Technology(ZY202001 and BS2020003).
文摘Magnesium alloy is one of the most widely used lightweight structural materials,and the development of high strength-toughness magnesium alloy is an important research field at present and even in the future.The preparation process parameters of magnesium alloy directly affect the microstructure of the magnesium alloy,and then determine the properties of the magnesium alloy.The cooling rate has important effects on the microstructure and properties of the magnesium alloy,and is an important preparation process parameter that cannot be ignored.Both the cooling rate from liquid phase to solid phase and the cooling rate of the magnesium alloy after heat treatment will change the microstructure of the magnesium alloy.Furthermore,the properties of magnesium alloy will be affected.In this paper,the effects of cooling rate on the solidification behavior,the rheological behavior,the change of microstructure(the solid solution of alloying elements in matrix,the composition,size,distribution and morphology of second phase,the diffusion and segregation of alloying elements,the grain size,the formation and morphology of dendrite,etc.),and the effects of cooling rate of magnesium alloy after heat treatment on the microstructure and stress distribution are reviewed.The reasons for the divergence about the influence of cooling rate on the microstructure of magnesium alloy are analyzed in detail.The effects of cooling rate on the mechanical properties,corrosion resistance and oxidation resistance of magnesium alloy are also analyzed and discussed deeply.Finally,the new methods and approaches to study the effects of cooling rate on the microstructure and properties of magnesium alloy are prospected.
文摘The effect of cooling rate after 40% hot deformation on structure and mechanical properties of low alloy wear resistance cast iron was investigated by metallographic, scanning electron microscopes and detection of properties. The results show that for the cast steel after deformed, the amount of granular carbides of precipitation during the cooling decreased with the increase of the cooling rate, but the hardness was obviously enhanced, as a result, better mechanical properties will be obtained by force air cooling(cooling rate is about 7 ℃·s-1). And the reason of the change for structure and mechanical properties of the cast steel were analyzed.
文摘Helicobacter pylori (H. pylori) eradication rates achieved with a proton pump inhibitor (PPI), amoxicillin and clarithromycin have recently decreased to about 75% because of the increase in clarithromycin resistance in Japan. In the present study, H. pylori resistance rates against clarithromycin, amoxicillin and metronidazole were investigated in pediatric patients and eradication rates were evaluated when tailored antibiotics regimens based on antibiotic sensitivity data were used. We isolated H. pylori endoscopically from 77 pediatric patients suffering from abdominal symptoms. The susceptibility tests of H. pylori strains to clarithromycin, amoxicillin and metronidazole were examined and eradication therapy was tailored using the appropriate antibiotics. Seventy-seven patients were treated with a mean age of 12.16 ± 3.34 years (range, 4.92-19.75) consisting of 40 males and 37 females. The average resistance rates between 1998 and 2016 to clarithromycin, amoxicillin and metronidazole were 54.5% (42 of 77), 6.5% (5 of 77) and 5.2% (4 of 77) respectively. The prevalence of clarithromycin resistance increased significantly over time to reach 88.9% by 2013-2016. Successful eradication rates using tailored antibiotic treatment was 93.8% (61 of 65). Clarithromycin-based eradication therapy rate reached 92.6% against clarithromycin-sensitive strains. Metronidazole-based initial eradication therapy also had a high successful rate (97.0%) to clarithromycin-resistant strains. Although high rates of clarithromycin resistant H. pylori reaching about 90% were observed in Japanese children, tailored eradication therapy using the appropriate antibiotic agents were highly successful. H. pylori sensitivity testing and eradication therapy with appropriate antibacterial agents may contribute to accomplishment of high initial eradication rates and consequently reducing the incidence of developing gastric cancer.
基金Project(51471050105HK0101) supported by the National Key Laboratory of Precision Thermal Treatment, Harbin Institute of Technology,China
文摘2195 aluminum-lithium alloy was widely applied in the aviation and aerospace industry, but it is highly susceptible to pitting and intergranular corrosion undergoing sever corrosive circumstance and moisture atmosphere. To solve this problem and consequently to prolong its service life, a multi-step-heating-rate(MSRC) process was carried out. Investigations were carried out to find the effect of the MSRC process on the alloys corrosion resistance. It is found that the MSRC process is more favorable for the uniform phase precipitation by comparing the corrosion resistance of samples treated by traditional heat treatments. The potential difference between phases can be reduced and intergranular corrosion is able to be prohibited efficiently. Besides, the rare earth infiltration is beneficial to improving the corrosion resistance. As heating time increases, the corrosion resistance declines gradually, samples treated by artificial aging and solid solution also exhibit a better corrosion resistance.
基金Project(2007CB613700)supported by the National Basic Research Program of China
文摘Mg-Gd-Y-Zr alloys were purified by filtering purification with and without vacuum. The type, morphology, size distribution and volume fraction of inclusion were analyzed with OM and SEM. The effect of inclusion in Mg-Gd-Y-Zr alloys on anticorrosion ability was investigated with salt spray test and electrochemical test. The results show that the inclusions in the alloy can be removed effectively by filtering purification. The average size of inclusions in the alloys is decreased from 12.7 μm to 2.0 μm and the volume fraction of inclusions is reduced from 0.30% to 0.04%. With the decrease of the size of inclusions in the alloys, the corrosion rate of the alloys decreases dramatically from 38.8 g/(m 2 ·d) to 2.4 g/(m 2 ·d) in the salt spray test. The corrosion potential increases while the corrosion current decreases and the polarization resistance increases in the electrochemical tests, which indicates that the anticorrosion ability is improved.
基金Project(2005CB623703)supported by the National Basic Research Program of ChinaProject(50721003)supported by the National Natural Science Foundation for Innovation Group of China+1 种基金Project(2008AA030501)supported by the National High-tech Research and Development Program of ChinaProject(201012200021)supported by the Basic Scientific Research Program of Central South University,China
文摘xCu/(10NiO-NiFe2O4) cermet and 1BaO-xCu/(10NiO-NiFe2O4) cermet(x=5,10,17) inert anodes were prepared as potential inert anodes for aluminum electrolysis and their corrosion resistance to traditional electrolyte was studied with anodic current density of 1.0 A/cm2 in laboratory electrolysis.The substantial corrosion of metal Cu was observed,many pores appeared on the surface of anode and electrolytes infiltrated inside anodes during the electrolysis.The wear rates of 5Cu/(10NiO-NiFe2O4),10Cu/(10NiO-NiFe2O4),17Cu/(10NiO-NiFe2O4),1BaO-5Cu/(10NiO-NiFe2O4),1BaO-10Cu/(10NiO-NiFe2O4) and 1BaO-17Cu/(10NiO-NiFe2O4) are 2.15,6.50,8.30,4.88,4.70 and 4.48 cm/a,respectively.The addition of BaO to 10Cu/(10NiO-NiFe2O4) cermet and 17Cu/(10NiO-NiFe2O4) cermet is advantageous because BaO can effectively promote densification and thus improve corrosion resistance.But the addition of BaO to 5Cu/(10NiO-NiFe2O4) cermet is unfavorable to corrosion resistance because additive BaO at the grain boundary of anode accelerates possibly the corrosion of cermet.
文摘The influence of chemical composition on corrosion resistance of AZ91D magnesium alloys ingots has been investigated. Mass loss method was applied to evaluate the corrosion resistance of AZ91D alloys and the data were analyzed by multiple regression. The results show that the corrosion resistance of this alloy can be improved by increasing Al, Zn and Mn in a certain degree, and will drop with increasing Si and heavy metals (Fe, Cu, Ni). It is found that ingots received from company F should be listed into unusable materials in terms of the corrosion resistance, while among the five suppliers, the only local company E supplied excellent AZ91D magnesium alloy ingots with the best corrosion resistance.
文摘To evaluate the efficacy of antimicrobial susceptibility-guided therapy before first-line treatment for infection in patients with dual or triple antibiotic resistance.METHODSA total of 1034 patients infected by Helicobacter pylori (H. pylori) during 2013-2014 were tested for antimicrobial susceptibility. 157 of 1034 (15%) patients showed resistance to two (127/1034; 12%) and to three (30/1034; 3%) antibiotics. Sixty-eight patients with dual H. pylori-resistance (clarithromycin, metronidazole or levofloxacin) were treated for 10 d with triple therapies: OAL (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and levofloxacin 500 mg b.i.d.) 43 cases, OAM (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and metronidazole 500 mg b.i.d.) 12 cases and OAC (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and clarithromycin 500 mg b.i.d.) 13 cases based on the antimicrobial susceptibility testing. Twelve patients showed triple H. pylori-resistance (clarithromycin, metronidazole and levofloxacin) and received for 10 d triple therapy with OAR (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and rifabutin 150 mg b.i.d.). Eradication was confirmed by 13C-urea breath test. Adverse effects and compliance were assessed by a questionnaire.RESULTSIntention-to-treat eradication rates were: OAL (97.6%), OAM (91.6%), OAC (92.3%) and OAR (58.3%). Cure rate was significantly higher in naïve patients treated with OAR-10 compared to patients who had two or three previous treatment failures (83% vs 33%). Adverse events rates for OAL, OAM, OAC and OAR were 22%, 25%, 23% and 17%, respectively, all of them mild-moderate.CONCLUSIONAntimicrobial susceptibility-guided triple therapies during 10 d for first-line treatment leads to an eradication rate superior to 90% in patients with dual antibiotic H. pylori resistance.
文摘Objective: To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods: Pathogenic bacteria identification and drug sensitivity tests were performed with a VITEK 2 compact automatic identification system and data were analyzed using WHONET5.6 software.Results: Of the 1,378 strains tested, 980 were Gram-negative bacilli, accounting for 71.1%, in which Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa were the dominant strains. We found 328 Gram-positive coccus, accounting for 23.8%, in which the amount of Staphylococcus aureus was the highest. We identified 46 fungi, accounting for 4.1%. According to the departmental distribution within the hospital, the surgical departments isolated the major strains, accounting for 49.7%. According to disease types, lung cancer, intestinal cancer and esophagus cancer were the top three, accounting for 20.9%, 17.3% and 14.2%, respectively. No strains were resistant to imipenem, ertapenem or vancomycin.Conclusions: Pathogenic bacteria isolated from the specialized cancer hospital have different resistance rates compared to commonly used antimicrobial agents; therefore antimicrobial agents to reduce the morbidity and mortality of infections should be used.
基金the National Natural Science Foundation of China (31871573)the National Key Research and Development Program of China (2016YFD0300505,2017YFD0301200 and 2018YFD0300803)the Jiangsu Key Research and Development Program,China (BE2017369)。
文摘To identify the major factors that contribute to the difference in lodging among different rice varieties under machine transplanting and their responses to nitrogen(N),field experiments were conducted at Danyang County(a representative eco-site of the Lower Yangtze River)in Jiangsu Province,China in 2017 and 2018,22 hybrid indica varieties(HIs),22 inbred japonica varieties(IJs)and two indica japonica hybrid varieties(IJHs)were transplanted by machine with three N rates(N0,N150 and N300,0,150 and 300 kg ha–1,respectively).Lodging-related physical parameters,morphological characteristics and apparent transport rates of dry matter were examined.Significant difference in yield was observed among different types of rice,and followed by IJs<HIs<IJHs.The average lodging index(LI)of hybrid varieties(HIs and IJHs)was higher than that of the inbred varieties(IJs)with higher plant height;moreover,lower apparent export rate of dry matter resulted lower LI in IJHs than in HIs.The HIs had a large difference in the LI,which came from the difference in bending stress(BS)induced by the difference in the apparent export rate of dry matter,varieties with lower leaf angle of upper three leaves possess strong lodging resistance capacity;however,the gap among the IJs was due to the difference in the cross section modulus(Z).The LI in the IJs or IJHs increased slightly with the increased N application,and there was no lodging incidence under the high N level,which was due to the low leaf angle and barely changed under high N;there was a significant interaction between varieties(HIs)and N rates in lodging rate and LI,varieties with lower leaf angle of upper three leaves were resistant to high N.These results suggest that compact plant type rice has higher lodging and N resistance at machine-transplanting method.
文摘To improve the crack-resistance of the mould for silica sol bonded quartz based ceramic mould casting,aluminum silicate fibers with the diameter ranging from 5 μm to 25 μm and the length about 1 mm were dispersed in the ceramic mould.The effect of the aluminum silicate fibers on the tensile strength,shrinkage rate and the cracking trend of the ceramic mould were investigated.In the ceramic slurry,quartz sand was applied as ceramic aggregate,silica sol containing 30% silicon dioxide as bonder,and the weight ratio of quartz sand to silica sol was 2.69;the dispersed fibers changed from 0 to 0.24vol.%.The mould samples were formed after the slurry was poured and gelled at room temperature,and then sintered at different temperatures ranging from 100 to 800 ℃ to measure the tensile strength and shrinkage rate.The results show that,with the aluminum silicate fiber addition increasing from 0 to 0.24vol.%,the tensile strength increases linearly from 0.175 MPa to 0.236 MPa,and the shrinkage rate decreases linearly from 1.75% to 1.68% for the ceramic mould sintered at 400 ℃,from 1.37% to 1.31% for the ceramic mould at room temperature.As the sintering temperature was raised from 100 ℃ to 800 ℃,the tensile strength increases,and the shrinkage rate decreases at all temperatures,compared with those without fiber dispersion,but their variation patterns remain the same.Furthermore,the cracking trend of the mould and its decreasing proportion were defined and analyzed quantitatively considering both effects of the fiber dispersion on the strength and shrinkage.The cracking trend appears to decrease linearly with increasing fiber content and to reach the maximum reduction of 28.8% when 0.24vol.% fiber was dispersed.Therefore,the investigation proposes a new method to improve the crack-resistance of the ceramic mould,i.e.,inorganic fiber dispersion into the ceramic mould.
基金Supported by Major Science and Technology Project of Henan Province"Gene Mining of Important Agronomic Traits in Major Crops and Breeding of New Corn Varieties"(161100110500-0104)
文摘Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.
基金Supported by Special Fund of Agricultural Science and Technology Achievement Transformation in Hebei Province(17826335D)Baoding Comprehensive Experimental Station of National Millet and Sorghum Industry Technology System(CARS-06-13.5-B2)
文摘In this study, the plant biomass production, biomass translocation rates across tissues and the lodging resistant-associated traits of millet ( Setaria italica L.) in North China were investigated. Among the four summer millet cultivars, Baogu 19 exhibited improved plant biomass (PB) production at flowering and maturity stages, biomass translocation amount (BTA) from vegetative tissues to seeds during filling period, and lodging resistant-associated (LRA) traits compared with other cultivars, including enhanced stem lignin contents, increased anti-broken resistance (ABR), anti-puncturing resistance (APR), and stem diameter (SD) of plants. Compared with treatment regular cultivation (RC), high fertility treatment (HF) increased the plant BP, BTA from vegetative tissue to seed at filling stage, and the plant LRA traits; whereas high density treatment (HD) decreased the plant BP at plant level, plant BTA from vegetative tissues to seeds at filling stage, and the plant LRA traits. Correlation analysis revealed that stem ABR is significantly correlated with the plant lodging resistant-associated traits including APR and SD in the summer millet cultivars examined under various cultivation treatments. Our investigation indicates that cultivar Baogu 19 together with suitable fertilization and density can promote the plant biomass production, enhance vegetative tissue biomass translocation to seeds, and improve the lodging resistance of summer millet plants in North China.