Research on the quasi-isentropic driving model of aluminized explosives in the detonation wave propagation direction

Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation direction.The research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was slowed down and even reversed to a slight rise due to the aftereffect reaction between the Al powder and the detonation products.

Epigenetic control on transcription of vernalization genes and whole-genome gene expression profile induced by vernalization in common wheat

Vernalization is necessary for winter wheat to flower.However,it is unclear whether vernalization is also required for spring wheat,which is frequently sown in fall,and what molecular mechanisms underlie the vernalization response in wheat varieties.In this study,we examined the molecular mechanisms that regulate vernalization response in winter and spring wheat varieties.For this purpose,we determined how major vernalization genes(VRN1,VRN2,and VRN3)respond to vernalization in these varieties and whether modifications to histones play a role in changes in gene expression.We also identified genes that are differentially regulated in response to vernalization in winter and spring wheat varieties.We found that in winter wheat,but not in spring wheat,VRN1 expression decreases when returned to warm temperature following vernalization.This finding may be associated with differences between spring and winter wheat in the levels of tri-methylation of lysine 27 on histone H3(H3K27me3)and tri-methylation of lysine 4 on histone H3(H3K4me3)at the VRN1 gene.Analysis of winter wheat transcriptomes before and after vernalization revealed that vernalization influences the expression of several genes,including those involved in leucine catabolism,cysteine biosynthesis,and flavonoid biosynthesis.These findings provide new candidates for further study on the mechanism of vernalization regulation in wheat.

Comprehensive integration of single-cell transcriptomic data illuminates the regulatory network architecture of plant cell fate specification

Plant morphogenesis relies on precise gene expression programs at the proper time and position which is orchestrated by transcription factors(TFs)in intricate regulatory networks in a cell-type specific manner.Here we introduced a comprehensive single-cell transcriptomic atlas of Arabidopsis seedlings.This atlas is the result of meticulous integration of 63 previously published scRNA-seq datasets,addressing batch effects and conserving biological variance.This integration spans a broad spectrum of tissues,including both below-and above-ground parts.Utilizing a rigorous approach for cell type annotation,we identified 47 distinct cell types or states,largely expanding our current view of plant cell compositions.We systematically constructed cell-type specific gene regulatory networks and uncovered key regulators that act in a coordinated manner to control cell-type specific gene expression.Taken together,our study not only offers extensive plant cell atlas exploration that serves as a valuable resource,but also provides molecular insights into gene-regulatory programs that varies from different cell types.

Surface ozone in global cities:A synthesis of basic features,exposure risk,and leading meteorological driving factors

Long-term exposure to high surface ozone(O_(3))concentrations,a complex oxidative atmospheric pollutant,can adversely impact human health.Based on O_(3)monitoring data from 261 cities worldwide in 2020,generalized additive model(GAM)and spatial data analysis(SDA)methods were applied in this study to quantitatively evaluate the spatiotemporal distribution of O_(3)concentration,exposure risk,and dominant meteorological factors.Results indicated that over 40%of the cities worldwide were exposed to harmful O_(3)concentration ranges(40-60μg/m^(3)),with most cities distributed in China and India.Moreover,significant seasonal variations in global O_(3)concentrations were observed,presenting as summer(45.6μg/m^(3))>spring(47.3μg/m^(3))>autumn(38.0μg/m^(3))>winter(33.6μg/m^(3)).Exposure analysis revealed that approximately 12.2%of the population in 261 cities were exposed to an environment with high O_(3)concentrations(80-160μg/m^(3)),with about 36.32 million people in major countries.Thus,the persistent increase in high O_(3)levels worldwide is a critical factor contributing to threats to human health.Furthermore,GAM results indicated temperature,relative humidity,and wind speed as primary determinants of O_(3)variability.The synergy of meteorological factors is critical for understanding O_(3)changes.Our findings are important for enforcing robust air quality policies and mitigating public risk.

Effects of Torreya grandis Root Rot on Seedling Growth and Screening of Its Chemical Control Agents

[Objectives]This study was conducted to prevent the occurrence of root rot disease in Torreya grandis and improve the yield and quality of T.grandis.[Methods]One-year-old and two-year-old seedlings of Torreya grandis‘Xifei’and‘Cufei’were inoculated with the root rot pathogen Fusarium fujikuroi,and the changes in photosynthesis,chlorophyll content,malondialdehyde,and defense enzyme system(superoxide dismutase,peroxidase,and catalase)activity in leaves of T.grandis seedlings were investigated using water as a control.Meanwhile,the control effects of 80%carbendazim wettable powder,64%metalaxyl·mancozeb wettable powder,430 g/L tebuconazole suspension and 30%difenoconazole·cyproconazole EC on root rot in T.grandis were investigated.[Results]After inoculation with the pathogen F.fujikuroi,the net photosynthetic rates and transpiration rates in leaves of T.grandis‘Xifei’and‘Cufei’decreased,and the contents of chlorophyll decreased,while the contents of malondialdehyde increased,and the contents of superoxide dismutase and catalase increased with time.However,peroxidase showed a high activity in T.grandis‘Cufei’only,but a trend of"increasing-decreasing-increasing"in T.grandis‘Xifei’.Among the four chemical control agents,64%metalaxyl·mancozeb wettable powder had the best control effect on root rot of T.grandis caused by the pathogenic fungus F.fujikuroi.[Conclusions]The net photosynthetic rate,transpiration rate,chlorophyll content,malondialdehyde content,superoxide dismutase activity and catalase activity could all be used as screening indicators for T.grandis varieties resistant to root rot.Meanwhile,64%metalaxyl·mancozeb wettable powder could be used as a control agent for root rot on T.grandis.

Three-dimensional conformal radiotherapy combined with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer

AIM： To investigate the effect of three-dimensional conformal radiotherapy （3-DCRT） in combination with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer. METHODS： Forty-eight patients with unresectable recurrent rectal cancer were randomized and treated by 3-DCRT or 3-DCRT combined with FOLFOX4 chemotherapy between September 2001 and October 2003. For the patients without prior radiation history, the initial radiation was given to the whole pelvis by traditional methods with tumor dose of 40 Gy, followed by 3-DCRT for the recurrent lesions to the median total cumulative tumor dose of 60 Gy （range 56-66 Gy）; for the post-radiation recurrent patients, 3-DCRT was directly given for the recurrent lesions to the median tumor dose of 40 Gy （36-46 Gy）. For patients in the study group, two cycles chemotherapy with FOLFOX4 regimen were given concurrently with radiotherapy, with the first cycle given simultaneously with the initiation of radiation and the second cycle given in the fifth week for patients receiving conventional pelvis radiation or given in the last week of 3-DCRT for patients receiving 3-DCRT directly. Another 2-4 cycles （average 3.6 cycles） sequential FOLFOX4 regimen chemotherapy were given to the patients in the study group, beginning at 2-3 wk after chemoradiation. The outcomes of symptoms relieve, tumor response, survival and toxicity were recorded and compared between the study group and the control group. RESULTS： For the study group and the control group, the pain-alleviation rates were 95.2% and 91.3%（P〉 0.05）; the overall response rates were 56.5% and 40.0% （P〉0.05）; the 1-year and 2-year survival rates were 86.9%, 50.2% and 80.0%, 23.9%, with median survival time of 25 mo and 16 mo （P〈 0.05）; the 2-year distant metastasis rates were 39.1% and 56.0% （P= 0.054）, respectively. The side effects, except peripheral neuropathy which was relatively severer in the study group, were similar in the the two groups and well tolerated. CONCLUSION： Three-dimensional conformal radiotherapy combined with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer is a feasible and effective therapeutic approach, and can reduce distant metastasis rate and improve the survival rate.

A Robustness Analysis of CMIP5 Models over the East Asia-Western North Pacific Domain

The Coupled Model Intercomparison Project （CMIP） is an international community-based infrastructure that supports climate model intercomparison, climate variability, climate prediction, and climate projection. Improving the performance of climate models over East Asia and the western North Pacific has been a challenge for the climate-modeling community. In this paper, we provide a synthesis robustness analysis of the climate models participating in CMIP-Phase 5 （CMIP5）. The strengths and weaknesses of the CMIP5 models are assessed from the perspective of climate mean state, interannual variability, past climate change during the mid-Pliocene （MP） and the last millennium, and climate projection. The added values of regional climate models relative to the driving global climate models are also assessed. Although an encouraging increase in credibility and an improvement in the simulation of mean states, interannual variability, and past climate changes are visible in the progression from CMIP3 to CMIPS, some previously noticed biases such as the ridge position of the western North Pacific subtropical high and the associated rainfall bias are still evident in CMIP5 models. Weaknesses are also evident in simulations of the interannual amplitude, such as El Nino- Southern Oscillation （ENSO）-monsoon relationships. Coupled models generally show better results than standalone atmospheric models in simulating both mean states and interannual variability. Multi-model intercomparison indicates significant uncertainties in the future projection of climate change, although precipitation increases consistently across models constrained by the Clausius-Clapeyron relation. Regional ocean-atmosphere coupled models are recommended for the dynamical downscaling of climate change oroiections over the East Asia-western North Pacific domain.

Recent progress in the study of methylated tumor suppressor genes in gastric cancer

Gastric cancer is one of the most common malignancies and a leading cause of cancer mortality worldwide.The pathogenesis mechanisms of gastric cancer are still not fully clear.Inactivation of tumor suppressor genes and activation of oncogenes caused by genetic and epigenetic alterations are known to play significant roles in carcinogenesis.Accumulating evidence has shown that epigenetic silencing of the tumor suppressor genes,particularly caused by hypermethylation of CpG islands in promoters,is critical to carcinogenesis and metastasis.Here,we review the recent progress in the study of methylations of tumor suppressor genes involved in the pathogenesis of gastric cancer.We also briefly describe the mechanisms that induce tumor suppressor gene methylation and the status of translating these molecular mechanisms into clinical applications.

Enhanced mechanical properties of Mg-3Al-1Zn alloy sheets through slope extrusion

A novel extrusion approach,entitled slope extrusion(SE),was employed to manufacture AZ31(Mg-3Al-1 Zn,wt%)alloy sheets.The microstructures,textures,and mechanical properties were investigated,compared with those of the AZ31 sheet fabricated by conventional extrusion(CE).Through the combination of finite element simulation and actual experiment,the ultimate results indicated that significant grain refinement(from 9.1 to 7.7 and 5.6μm)and strong basal texture(from 12.6 to 17.6 and 19.5 mrd)were achieved by the SE process.The essence was associated with the additional introduced inclined interface in the process of SE,which could bring about more asymmetric deformation and stronger accumulated strain along the ND when compared with the process of CE.As a consequence,the SE sheets exhibited a higher yield strength(YS)and ultimate tensile strength(UTS)than the counterparts of the CE sheet,which was mainly assigned to the synergistic effects from grain refining and texture strengthening.

Improving the room-temperature bendability of Mg-3Al-1Zn alloy sheet by introducing a bimodal microstructure and the texture re-orientation

A significant enhancement of bendability was achieved by the introduction of bimodal microstructure for AZ31B alloy sheets via pre-compression and subsequent annealing(PCA)process.This combined treatment led to the c-axis of the extracted samples that were inclined by 30°to the rolling direction(30°sample)further shifting toward the rolling direction(RD)and resulting in a higher Schmid factor(SF)value of basal slip under the RD tensile stress.Furthermore,the bimodal microstructure that was introduced by the PCA process broke the damage bands(DBs)in the initial hot rolled AZ31B alloy sheets and gave rise to a more uniform strain distribution in the outer tension region of the bending samples,in which the tensile deformation was accommodated by the equally distributed{101^(-)2}tension twinning and basal slip.Consequently,the bimodal microstructure,shifted basal texture and the modification of DBs were responsible for the significant enhancement in the bendability of the AZ31 alloys.

In situ Raman spectroscopy reveals the mechanism of titanium substitution in P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2): Cathode materials for sodium batteries

Layered P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 is a promising cathode material. It exhibits a high capacity and suitable operating voltage and undergoes a phase transition from P2 to O2 during charge/discharge.Researchers have used Ti substitution to improve the cathode, yet the chemical principles that underpin elemental substitution and functional improvement remain unclear. To clarify these principles, we used in situ Raman spectroscopy to monitor chemical changes in P2–Na2/3 Ni1/3 Mn1/3 Ti1/3 O2 and P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 during charge/discharge. Based on the change in the A_(1g) and E_g peaks during charge/discharge, we concluded that Ti substitution compressed the transition metal layer and expanded the planar oxygen layer in the unit cell. Titanium stabilized the P2 phase structure, which improved the cycling stability of P2–NaNMT. Our results provide clear theoretical support for future research on modifying electrodes by elemental substitution.

Effect of ultrasonic peening treatment on the fatigue behaviors of a magnesium alloy up to very high cycle regime

Ultrasonic fatigue tests are performed on a magnesium alloy with and without ultrasonic peening treatment(UPT).Surface enhancement layer leads to the complete change of crack initiation sites.However,crack initiation mechanism keeps the same and results in a single-faceted morphology at crack initiation site.Microcracks initiate as Mode Ⅱ crack within the original grain,but deflect to Mode I crack outside of the original cracked grain.A threshold SIF value is proposed to evaluate the retarding effect of grain boundary on microcrack propagation.Outside of the original cracked grain,Mode I crack propagation below the threshold ΔK_(σ-th) is responsible for the formation of fine granular area(FGA,a nano-grain layer).Based on the Numerous Cyclic Pressing(NCP) model,it is proposed that crack type should be another necessary condition for the formation of FGA.

基于弯曲定径带模具挤压的Mg-3Al-1Zn合金力学性能优化

设计了一种采用弯曲定径带模具的新型非对称挤压工艺(TBE),用以改善Mg-3Al-1Zn合金板材的力学性能和成形性能。运用有限元分析揭示了挤压过程中的应变、温度等状态变量的分布。结果表明,在TBE模具的模口处,应变沿板面法向(ND)呈梯度分布,这导致挤压板材显微组织的厚向梯度分布,同时得到TD择优取向的织构,少量基面取向晶粒向挤压方向(ED)偏转。与传统挤压相比,TBE过程中产生更多挤压热,模腔内温度更高,使大量非基面滑移开启,导致板材TD择优取向织构的形成。通过改善织构,TBE板材的塑性和弯曲性能均得到明显提升,沿45°方向的伸长率达到33%,弯曲角度达到83.5°。

Effect of long-period stacking ordered structure on very high cycle fatigue properties of Mg-Gd-Y-Zn-Zr alloys

Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on the crack behaviors of Mg alloys in a very high cycle fatigue(VHCF)regime.The LPSO lamellas lead to a facet-like cracking process along the basal planes at the crack initiation site and strongly prohibit the early crack propagation by deflecting the growth direction.The stress intensity factor at the periphery of the faceted area is much higher than the conventional LPSO-free Mg alloys,contributing higher fatigue crack propagation threshold of LPSO-containing Mg alloys.Microstructure observation at the facets reveals a layer of ultrafine grains at the fracture surface due to the cyclic contact of the crack surface,which supports the numerous cyclic pressing model describing the VHCF crack initiation behavior.

Dissecting the molecular basis of spike traits by integrating gene regulatory networks and genetic variation in wheat

Spike architecture influences both grain weight and grain number per spike,which are the two major components of grain yield in bread wheat(Triticum aestivum L.).However,the complex wheat genome and the influence of various environmental factors pose challenges in mapping the causal genes that affect spike traits.Here,we systematically identified genes involved in spike trait formation by integrating information on genomic variation and gene regulatory networks controlling young spike development in wheat.We identified 170 loci that are responsible for variations in spike length,spikelet number per spike,and grain number per spike through genome-wide association study and meta-QTL analyses.We constructed gene regulatory networks for young inflorescences at the double ridge stage and thefloret primordium stage,in which the spikelet meristem and thefloret meristem are predominant,respec-tively,by integrating transcriptome,histone modification,chromatin accessibility,eQTL,and protein–pro-tein interactome data.From these networks,we identified 169 hub genes located in 76 of the 170 QTL regions whose polymorphisms are significantly associated with variation in spike traits.The functions of TaZF-B1,VRT-B2,and TaSPL15-A/D in establishment of wheat spike architecture were verified.This study provides valuable molecular resources for understanding spike traits and demonstrates that combining genetic analysis and developmental regulatory networks is a robust approach for dissection of complex traits.

Effect of gradient microstructure on the bendability of AZ31 alloy sheet

Extensive researches have elucidated the pronounced benefits of gradient microstructures for the me-chanical properties of metallic materials.However,the ramifications of gradient microstructures on formability,particularly regarding their effects on bendability,remain inadequately understood.In this work,the effects of gradient microstructure on the bendability of AZ31 Mg alloy sheet are systematically investigated by comparing the microstructure evolution and strain distribution in the sheets with uni-form microstructure(grain size=12.8 μm and 91.3 μm)and gradient microstructure(grain size=11.5-75.4 μm).The results show that the bendability of the sheet with gradient microstructure is significantly improved when the fine grains(FGs)are placed at the outer side(TBE-FG sample)and the bendability is increased by 93.1%compared to the sample with fine and uniform microstructure(CE-FG sample).With coarse grains(CGs)placed at the inner side,the strain at the compressive region of the TBE-FG sample is higher than its counterparts,while the tensile strain at the extended region is lowest among the four samples.Quasi-in-situ bending experiments reveal that the CGs at the inner side of the TBE-FG sample undergo more twinning.Moreover,the increment of residual dislocation density at the outer side of the TBE-FG sample is lower than those of other samples,which extends the bending potential.This work provides a novel perspective to improve the bendability of the Mg alloy sheet.

Overcoming genotypic dependency and bypassing immature embryos in wheat transformation by using morphogenic regulators

Dear Editor,Agrobacterium-mediated transformation technology is of vital importance for functional genomics studies and precision breeding in crops due to low cost and clear genetic manifestation.A morphogenic gene pair,BABY BOOM and WUSCHEL(BBM-WUS).

Layered(C_(5)H_(6)ON)_(2)[Sb_(2)O(C_(2)O_(4))_(3)]with a large birefringence derived from the uniform arrangement of π-conjugated units

An organic-inorganic hybrid antimony(Ⅲ)oxalate(C_(5)H_(6)ON)_(2)[Sb_(2)O(C_(2)O_(4))_(3)]has been successfully obtained by simultaneous combination of a-conjugated 4-hydroxypyridine and(C_(2)O_(4))^(2-)group with stereochemical active Sb(Ⅲ)cation.The compound features a layered structure,and the equatorial planes of SbO6 units,π-conjugated(C_(2)O_(4))^(2-)and(C5H6ON)+groups are closer to a planar arrangement,representing strong structural anisotropy that favors a large birefringence.As expected,(C_(5)H_(6)ON)_(2)[Sb_(2)O(C_(2)O_(4))_(3)]exhibits a large birefringence of 0.279 at 546 nm.Structural and theoretical analyses indicate that the combination of multipleπ-conjugated units is a feasible approach for designing and exploring new superior birefringent materials.

Synergistic PM_(2.5)and O_(3)control to address the emerging global PM_(2.5)-O_(3)compound pollution challenges

In recent years,the issue of PM_(2.5)-O_(3)compound pollution has become a significant global environmental concern.This study examines the spatial and temporal patterns of global PM_(2.5)-O_(3)compound pollution and exposure risks,firstly at the global and urban scale,using spatial statistical regression,exposure risk assessment,and trend analyses based on the datasets of daily PM_(2.5)and surface O_(3)concentrations monitored in 120 cities around the world from 2019 to 2022.Additionally,on the basis of the common emission sources,spatial heterogeneity,interacting chemical mechanisms,and synergistic exposure risk levels between PM_(2.5)and O_(3)pollution,we proposed a synergistic PM_(2.5)-O_(3)control framework for the joint control of PM_(2.5)and O3.The results indicated that:(1)Nearly 50%of cities worldwide were affected by PM_(2.5)-O_(3)compound pollution,with China,South Korea,Japan,and India being the global hotspots for PM2.5-O3 compound pollution;(2)Cities with PM_(2.5)-O_(3)compound pollution have exposure risk levels dominated by ST t ST(Stabilization)and ST t HR(High Risk).Exposure risk levels of compound pollution in developing countries are significantly higher than those in developed countries,with unequal exposure characteristics;(3)The selected cities showed significant positive spatial correlations between PM_(2.5)and O_(3)concentrations,which were consistent with the spatial distribution of the precursors NOx and VOCs;(4)During the study period,52.5%of cities worldwide achieved synergistic reductions in annual average PM_(2.5)and O_(3)concentrations.The average PM_(2.5)concentration in these cities decreased by 13.97%,while the average O_(3)concentration decreased by 19.18%.This new solution offers the opportunity to construct intelligent and healthy cities in the upcoming low–carbon transition.

子宫内膜搔刮术对不孕女性妊娠结局的影响

目的探索子宫内膜搔刮术对首次行IVF/ICSI-ET的不孕女性妊娠结局的影响。方法分析2012年1月至2014年12月在我院行IVF/ICSI-ET的助孕患者142例,根据随机数字表法,将患者分为干预组(70例)和对照组(72例)。干预组于胚胎移植前一周期的卵泡期或黄体期行子宫内膜搔刮,对照组不予任何处理,比较两组患者的一般情况及妊娠结局。结果两组患者的年龄、不孕年限、不孕原因、体重指数等一般情况均无显著性差异(P均>0.05)。干预组的种植率、生化妊娠率、临床妊娠率、流产率、多胎率及活产率分别为27.2%、54.3%、41.4%、3.4%、34.5%及35.7%,对照组分别为26.7%、52.8%、41.7%、3.3%、30.0%及40.3%,两组间比较无显著性差异(P均>0.05)。结论在胚胎移植前一周期的卵泡期或黄体期对首次行IVF/ICSI助孕的不孕女性行1次内膜搔刮,并不能改善不孕女性的妊娠结局。